WordPress/wp-includes/post.php

<?php
/**
 * Post functions and post utility function.
 *
 * @package WordPress
 * @subpackage Post
 * @since 1.5.0
 */

//
// Post Type Registration
//

/**
 * Creates the initial post types when 'init' action is fired.
 *
 * @since 2.9.0
 */
function create_initial_post_types() {
	register_post_type( 'post', array(
		'labels' => array(
			'name_admin_bar' => _x( 'Post', 'add new on admin bar' ),
		),
		'public'  => true,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'map_meta_cap' => true,
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
		'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'excerpt', 'trackbacks', 'custom-fields', 'comments', 'revisions', 'post-formats' ),
	) );

	register_post_type( 'page', array(
		'labels' => array(
			'name_admin_bar' => _x( 'Page', 'add new on admin bar' ),
		),
		'public' => true,
		'publicly_queryable' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'post.php?post=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'page',
		'map_meta_cap' => true,
		'hierarchical' => true,
		'rewrite' => false,
		'query_var' => false,
		'supports' => array( 'title', 'editor', 'author', 'thumbnail', 'page-attributes', 'custom-fields', 'comments', 'revisions' ),
	) );

	register_post_type( 'attachment', array(
		'labels' => array(
			'name' => __( 'Media' ),
			'edit_item' => __( 'Edit Media' ),
		),
		'public' => true,
		'show_ui' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'media.php?attachment_id=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'map_meta_cap' => true,
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
		'show_in_nav_menus' => false,
		'supports' => array( 'comments' ),
	) );

	register_post_type( 'revision', array(
		'labels' => array(
			'name' => __( 'Revisions' ),
			'singular_name' => __( 'Revision' ),
		),
		'public' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'_edit_link' => 'revision.php?revision=%d', /* internal use only. don't use this when registering your own post type. */
		'capability_type' => 'post',
		'map_meta_cap' => true,
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
		'can_export' => false,
	) );

	register_post_type( 'nav_menu_item', array(
		'labels' => array(
			'name' => __( 'Navigation Menu Items' ),
			'singular_name' => __( 'Navigation Menu Item' ),
		),
		'public' => false,
		'_builtin' => true, /* internal use only. don't use this when registering your own post type. */
		'hierarchical' => false,
		'rewrite' => false,
		'query_var' => false,
	) );

	register_post_status( 'publish', array(
		'label'       => _x( 'Published', 'post' ),
		'public'      => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Published <span class="count">(%s)</span>', 'Published <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'future', array(
		'label'       => _x( 'Scheduled', 'post' ),
		'protected'   => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop('Scheduled <span class="count">(%s)</span>', 'Scheduled <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'draft', array(
		'label'       => _x( 'Draft', 'post' ),
		'protected'   => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Draft <span class="count">(%s)</span>', 'Drafts <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'pending', array(
		'label'       => _x( 'Pending', 'post' ),
		'protected'   => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Pending <span class="count">(%s)</span>', 'Pending <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'private', array(
		'label'       => _x( 'Private', 'post' ),
		'private'     => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Private <span class="count">(%s)</span>', 'Private <span class="count">(%s)</span>' ),
	) );

	register_post_status( 'trash', array(
		'label'       => _x( 'Trash', 'post' ),
		'internal'    => true,
		'_builtin'    => true, /* internal use only. */
		'label_count' => _n_noop( 'Trash <span class="count">(%s)</span>', 'Trash <span class="count">(%s)</span>' ),
		'show_in_admin_status_list' => true,
	) );

	register_post_status( 'auto-draft', array(
		'label'    => 'auto-draft',
		'internal' => true,
		'_builtin' => true, /* internal use only. */
	) );

	register_post_status( 'inherit', array(
		'label'    => 'inherit',
		'internal' => true,
		'_builtin' => true, /* internal use only. */
		'exclude_from_search' => false,
	) );
}
add_action( 'init', 'create_initial_post_types', 0 ); // highest priority

/**
 * Retrieve attached file path based on attachment ID.
 *
 * You can optionally send it through the 'get_attached_file' filter, but by
 * default it will just return the file path unfiltered.
 *
 * The function works by getting the single post meta name, named
 * '_wp_attached_file' and returning it. This is a convenience function to
 * prevent looking up the meta name and provide a mechanism for sending the
 * attached filename through a filter.
 *
 * @since 2.0.0
 * @uses apply_filters() Calls 'get_attached_file' on file path and attachment ID.
 *
 * @param int $attachment_id Attachment ID.
 * @param bool $unfiltered Whether to apply filters.
 * @return string|bool The file path to the attached file, or false if the attachment does not exist.
 */
function get_attached_file( $attachment_id, $unfiltered = false ) {
	$file = get_post_meta( $attachment_id, '_wp_attached_file', true );
	// If the file is relative, prepend upload dir
	if ( $file && 0 !== strpos($file, '/') && !preg_match('|^.:\\\|', $file) && ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) )
		$file = $uploads['basedir'] . "/$file";
	if ( $unfiltered )
		return $file;
	return apply_filters( 'get_attached_file', $file, $attachment_id );
}

/**
 * Update attachment file path based on attachment ID.
 *
 * Used to update the file path of the attachment, which uses post meta name
 * '_wp_attached_file' to store the path of the attachment.
 *
 * @since 2.1.0
 * @uses apply_filters() Calls 'update_attached_file' on file path and attachment ID.
 *
 * @param int $attachment_id Attachment ID
 * @param string $file File path for the attachment
 * @return bool False on failure, true on success.
 */
function update_attached_file( $attachment_id, $file ) {
	if ( !get_post( $attachment_id ) )
		return false;

	$file = apply_filters( 'update_attached_file', $file, $attachment_id );
	$file = _wp_relative_upload_path($file);

	return update_post_meta( $attachment_id, '_wp_attached_file', $file );
}

/**
 * Return relative path to an uploaded file.
 *
 * The path is relative to the current upload dir.
 *
 * @since 2.9.0
 * @uses apply_filters() Calls '_wp_relative_upload_path' on file path.
 *
 * @param string $path Full path to the file
 * @return string relative path on success, unchanged path on failure.
 */
function _wp_relative_upload_path( $path ) {
	$new_path = $path;

	if ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) {
		if ( 0 === strpos($new_path, $uploads['basedir']) ) {
				$new_path = str_replace($uploads['basedir'], '', $new_path);
				$new_path = ltrim($new_path, '/');
		}
	}

	return apply_filters( '_wp_relative_upload_path', $new_path, $path );
}

/**
 * Retrieve all children of the post parent ID.
 *
 * Normally, without any enhancements, the children would apply to pages. In the
 * context of the inner workings of WordPress, pages, posts, and attachments
 * share the same table, so therefore the functionality could apply to any one
 * of them. It is then noted that while this function does not work on posts, it
 * does not mean that it won't work on posts. It is recommended that you know
 * what context you wish to retrieve the children of.
 *
 * Attachments may also be made the child of a post, so if that is an accurate
 * statement (which needs to be verified), it would then be possible to get
 * all of the attachments for a post. Attachments have since changed since
 * version 2.5, so this is most likely unaccurate, but serves generally as an
 * example of what is possible.
 *
 * The arguments listed as defaults are for this function and also of the
 * {@link get_posts()} function. The arguments are combined with the
 * get_children defaults and are then passed to the {@link get_posts()}
 * function, which accepts additional arguments. You can replace the defaults in
 * this function, listed below and the additional arguments listed in the
 * {@link get_posts()} function.
 *
 * The 'post_parent' is the most important argument and important attention
 * needs to be paid to the $args parameter. If you pass either an object or an
 * integer (number), then just the 'post_parent' is grabbed and everything else
 * is lost. If you don't specify any arguments, then it is assumed that you are
 * in The Loop and the post parent will be grabbed for from the current post.
 *
 * The 'post_parent' argument is the ID to get the children. The 'numberposts'
 * is the amount of posts to retrieve that has a default of '-1', which is
 * used to get all of the posts. Giving a number higher than 0 will only
 * retrieve that amount of posts.
 *
 * The 'post_type' and 'post_status' arguments can be used to choose what
 * criteria of posts to retrieve. The 'post_type' can be anything, but WordPress
 * post types are 'post', 'pages', and 'attachments'. The 'post_status'
 * argument will accept any post status within the write administration panels.
 *
 * @see get_posts() Has additional arguments that can be replaced.
 * @internal Claims made in the long description might be inaccurate.
 *
 * @since 2.0.0
 *
 * @param mixed $args Optional. User defined arguments for replacing the defaults.
 * @param string $output Optional. Constant for return type, either OBJECT (default), ARRAY_A, ARRAY_N.
 * @return array|bool False on failure and the type will be determined by $output parameter.
 */
function get_children($args = '', $output = OBJECT) {
	$kids = array();
	if ( empty( $args ) ) {
		if ( isset( $GLOBALS['post'] ) ) {
			$args = array('post_parent' => (int) $GLOBALS['post']->post_parent );
		} else {
			return $kids;
		}
	} elseif ( is_object( $args ) ) {
		$args = array('post_parent' => (int) $args->post_parent );
	} elseif ( is_numeric( $args ) ) {
		$args = array('post_parent' => (int) $args);
	}

	$defaults = array(
		'numberposts' => -1, 'post_type' => 'any',
		'post_status' => 'any', 'post_parent' => 0,
	);

	$r = wp_parse_args( $args, $defaults );

	$children = get_posts( $r );

	if ( !$children )
		return $kids;

	update_post_cache($children);

	foreach ( $children as $key => $child )
		$kids[$child->ID] = $children[$key];

	if ( $output == OBJECT ) {
		return $kids;
	} elseif ( $output == ARRAY_A ) {
		foreach ( (array) $kids as $kid )
			$weeuns[$kid->ID] = get_object_vars($kids[$kid->ID]);
		return $weeuns;
	} elseif ( $output == ARRAY_N ) {
		foreach ( (array) $kids as $kid )
			$babes[$kid->ID] = array_values(get_object_vars($kids[$kid->ID]));
		return $babes;
	} else {
		return $kids;
	}
}

/**
 * Get extended entry info (<!--more-->).
 *
 * There should not be any space after the second dash and before the word
 * 'more'. There can be text or space(s) after the word 'more', but won't be
 * referenced.
 *
 * The returned array has 'main', 'extended', and 'more_text' keys. Main has the text before
 * the <code><!--more--></code>. The 'extended' key has the content after the
 * <code><!--more--></code> comment. The 'more_text' key has the custom "Read More" text.
 *
 * @since 1.0.0
 *
 * @param string $post Post content.
 * @return array Post before ('main'), after ('extended'), and custom readmore ('more_text').
 */
function get_extended($post) {
	//Match the new style more links
	if ( preg_match('/<!--more(.*?)?-->/', $post, $matches) ) {
		list($main, $extended) = explode($matches[0], $post, 2);
		$more_text = $matches[1];
	} else {
		$main = $post;
		$extended = '';
		$more_text = '';
	}

	// Strip leading and trailing whitespace
	$main = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $main);
	$extended = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $extended);
	$more_text = preg_replace('/^[\s]*(.*)[\s]*$/', '\\1', $more_text);

	return array( 'main' => $main, 'extended' => $extended, 'more_text' => $more_text );
}

/**
 * Retrieves post data given a post ID or post object.
 *
 * See {@link sanitize_post()} for optional $filter values. Also, the parameter
 * $post, must be given as a variable, since it is passed by reference.
 *
 * @since 1.5.1
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/get_post
 *
 * @param int|object $post Post ID or post object.
 * @param string $output Optional, default is Object. Either OBJECT, ARRAY_A, or ARRAY_N.
 * @param string $filter Optional, default is raw.
 * @return mixed Post data
 */
function &get_post(&$post, $output = OBJECT, $filter = 'raw') {
	global $wpdb;
	$null = null;

	if ( empty($post) ) {
		if ( isset($GLOBALS['post']) )
			$_post = & $GLOBALS['post'];
		else
			return $null;
	} elseif ( is_object($post) && empty($post->filter) ) {
		_get_post_ancestors($post);
		$_post = sanitize_post($post, 'raw');
		wp_cache_add($post->ID, $_post, 'posts');
	} elseif ( is_object($post) && 'raw' == $post->filter ) {
		$_post = $post;
	} else {
		if ( is_object($post) )
			$post_id = $post->ID;
		else
			$post_id = $post;

		$post_id = (int) $post_id;
		if ( ! $_post = wp_cache_get($post_id, 'posts') ) {
			$_post = $wpdb->get_row($wpdb->prepare("SELECT * FROM $wpdb->posts WHERE ID = %d LIMIT 1", $post_id));
			if ( ! $_post )
				return $null;
			_get_post_ancestors($_post);
			$_post = sanitize_post($_post, 'raw');
			wp_cache_add($_post->ID, $_post, 'posts');
		}
	}

	if ($filter != 'raw')
		$_post = sanitize_post($_post, $filter);

	if ( $output == OBJECT ) {
		return $_post;
	} elseif ( $output == ARRAY_A ) {
		$__post = get_object_vars($_post);
		return $__post;
	} elseif ( $output == ARRAY_N ) {
		$__post = array_values(get_object_vars($_post));
		return $__post;
	} else {
		return $_post;
	}
}

/**
 * Retrieve ancestors of a post.
 *
 * @since 2.5.0
 *
 * @param int|object $post Post ID or post object
 * @return array Ancestor IDs or empty array if none are found.
 */
function get_post_ancestors($post) {
	$post = get_post($post);

	if ( ! isset( $post->ancestors ) )
		_get_post_ancestors( $post );

	if ( ! empty( $post->ancestors ) )
		return $post->ancestors;

	return array();
}

/**
 * Retrieve data from a post field based on Post ID.
 *
 * Examples of the post field will be, 'post_type', 'post_status', 'post_content',
 * etc and based off of the post object property or key names.
 *
 * The context values are based off of the taxonomy filter functions and
 * supported values are found within those functions.
 *
 * @since 2.3.0
 * @uses sanitize_post_field() See for possible $context values.
 *
 * @param string $field Post field name
 * @param id $post Post ID
 * @param string $context Optional. How to filter the field. Default is display.
 * @return WP_Error|string Value in post field or WP_Error on failure
 */
function get_post_field( $field, $post, $context = 'display' ) {
	$post = (int) $post;
	$post = get_post( $post );

	if ( is_wp_error($post) )
		return $post;

	if ( !is_object($post) )
		return '';

	if ( !isset($post->$field) )
		return '';

	return sanitize_post_field($field, $post->$field, $post->ID, $context);
}

/**
 * Retrieve the mime type of an attachment based on the ID.
 *
 * This function can be used with any post type, but it makes more sense with
 * attachments.
 *
 * @since 2.0.0
 *
 * @param int $ID Optional. Post ID.
 * @return bool|string False on failure or returns the mime type
 */
function get_post_mime_type($ID = '') {
	$post = & get_post($ID);

	if ( is_object($post) )
		return $post->post_mime_type;

	return false;
}

/**
 * Retrieve the format slug for a post
 *
 * @since 3.1.0
 *
 * @param int|object $post A post
 *
 * @return mixed The format if successful. False if no format is set. WP_Error if errors.
 */
function get_post_format( $post = null ) {
	$post = get_post($post);

	if ( ! post_type_supports( $post->post_type, 'post-formats' ) )
		return false;

	$_format = get_the_terms( $post->ID, 'post_format' );

	if ( empty( $_format ) )
		return false;

	$format = array_shift( $_format );

	return ( str_replace('post-format-', '', $format->slug ) );
}

/**
 * Check if a post has a particular format
 *
 * @since 3.1.0
 * @uses has_term()
 *
 * @param string $format The format to check for
 * @param object|id $post The post to check. If not supplied, defaults to the current post if used in the loop.
 * @return bool True if the post has the format, false otherwise.
 */
function has_post_format( $format, $post = null ) {
	return has_term('post-format-' . sanitize_key($format), 'post_format', $post);
}

/**
 * Assign a format to a post
 *
 * @since 3.1.0
 *
 * @param int|object $post The post for which to assign a format
 * @param string $format  A format to assign. Use an empty string or array to remove all formats from the post.
 * @return mixed WP_Error on error. Array of affected term IDs on success.
 */
function set_post_format( $post, $format ) {
	$post = get_post($post);

	if ( empty($post) )
		return new WP_Error('invalid_post', __('Invalid post'));

	if ( !empty($format) ) {
		$format = sanitize_key($format);
		if ( 'standard' == $format || !in_array( $format, array_keys( get_post_format_slugs() ) ) )
			$format = '';
		else
			$format = 'post-format-' . $format;
	}

	return wp_set_post_terms($post->ID, $format, 'post_format');
}

/**
 * Retrieve the post status based on the Post ID.
 *
 * If the post ID is of an attachment, then the parent post status will be given
 * instead.
 *
 * @since 2.0.0
 *
 * @param int $ID Post ID
 * @return string|bool Post status or false on failure.
 */
function get_post_status($ID = '') {
	$post = get_post($ID);

	if ( !is_object($post) )
		return false;

	if ( 'attachment' == $post->post_type ) {
		if ( 'private' == $post->post_status )
			return 'private';

		// Unattached attachments are assumed to be published
		if ( ( 'inherit' == $post->post_status ) && ( 0 == $post->post_parent) )
			return 'publish';

		// Inherit status from the parent
		if ( $post->post_parent && ( $post->ID != $post->post_parent ) )
			return get_post_status($post->post_parent);
	}

	return $post->post_status;
}

/**
 * Retrieve all of the WordPress supported post statuses.
 *
 * Posts have a limited set of valid status values, this provides the
 * post_status values and descriptions.
 *
 * @since 2.5.0
 *
 * @return array List of post statuses.
 */
function get_post_statuses( ) {
	$status = array(
		'draft'			=> __('Draft'),
		'pending'		=> __('Pending Review'),
		'private'		=> __('Private'),
		'publish'		=> __('Published')
	);

	return $status;
}

/**
 * Retrieve all of the WordPress support page statuses.
 *
 * Pages have a limited set of valid status values, this provides the
 * post_status values and descriptions.
 *
 * @since 2.5.0
 *
 * @return array List of page statuses.
 */
function get_page_statuses( ) {
	$status = array(
		'draft'			=> __('Draft'),
		'private'		=> __('Private'),
		'publish'		=> __('Published')
	);

	return $status;
}

/**
 * Register a post status. Do not use before init.
 *
 * A simple function for creating or modifying a post status based on the
 * parameters given. The function will accept an array (second optional
 * parameter), along with a string for the post status name.
 *
 *
 * Optional $args contents:
 *
 * label - A descriptive name for the post status marked for translation. Defaults to $post_status.
 * public - Whether posts of this status should be shown in the front end of the site. Defaults to true.
 * exclude_from_search - Whether to exclude posts with this post status from search results. Defaults to false.
 * show_in_admin_all_list - Whether to include posts in the edit listing for their post type
 * show_in_admin_status_list - Show in the list of statuses with post counts at the top of the edit
 *                             listings, e.g. All (12) | Published (9) | My Custom Status (2) ...
 *
 * Arguments prefixed with an _underscore shouldn't be used by plugins and themes.
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_statuses Inserts new post status object into the list
 *
 * @param string $post_status Name of the post status.
 * @param array|string $args See above description.
 */
function register_post_status($post_status, $args = array()) {
	global $wp_post_statuses;

	if (!is_array($wp_post_statuses))
		$wp_post_statuses = array();

	// Args prefixed with an underscore are reserved for internal use.
	$defaults = array('label' => false, 'label_count' => false, 'exclude_from_search' => null, '_builtin' => false, '_edit_link' => 'post.php?post=%d', 'capability_type' => 'post', 'hierarchical' => false, 'public' => null, 'internal' => null, 'protected' => null, 'private' => null, 'show_in_admin_all' => null, 'publicly_queryable' => null, 'show_in_admin_status_list' => null, 'show_in_admin_all_list' => null, 'single_view_cap' => null);
	$args = wp_parse_args($args, $defaults);
	$args = (object) $args;

	$post_status = sanitize_key($post_status);
	$args->name = $post_status;

	if ( null === $args->public && null === $args->internal && null === $args->protected && null === $args->private )
		$args->internal = true;

	if ( null === $args->public  )
		$args->public = false;

	if ( null === $args->private  )
		$args->private = false;

	if ( null === $args->protected  )
		$args->protected = false;

	if ( null === $args->internal  )
		$args->internal = false;

	if ( null === $args->publicly_queryable )
		$args->publicly_queryable = $args->public;

	if ( null === $args->exclude_from_search )
		$args->exclude_from_search = $args->internal;

	if ( null === $args->show_in_admin_all_list )
		$args->show_in_admin_all_list = !$args->internal;

	if ( null === $args->show_in_admin_status_list )
			$args->show_in_admin_status_list = !$args->internal;

	if ( null === $args->single_view_cap )
		$args->single_view_cap = $args->public ? '' : 'edit';

	if ( false === $args->label )
		$args->label = $post_status;

	if ( false === $args->label_count )
		$args->label_count = array( $args->label, $args->label );

	$wp_post_statuses[$post_status] = $args;

	return $args;
}

/**
 * Retrieve a post status object by name
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_statuses
 * @see register_post_status
 * @see get_post_statuses
 *
 * @param string $post_status The name of a registered post status
 * @return object A post status object
 */
function get_post_status_object( $post_status ) {
	global $wp_post_statuses;

	if ( empty($wp_post_statuses[$post_status]) )
		return null;

	return $wp_post_statuses[$post_status];
}

/**
 * Get a list of all registered post status objects.
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_statuses
 * @see register_post_status
 * @see get_post_status_object
 *
 * @param array|string $args An array of key => value arguments to match against the post status objects.
 * @param string $output The type of output to return, either post status 'names' or 'objects'. 'names' is the default.
 * @param string $operator The logical operation to perform. 'or' means only one element
 *  from the array needs to match; 'and' means all elements must match. The default is 'and'.
 * @return array A list of post type names or objects
 */
function get_post_stati( $args = array(), $output = 'names', $operator = 'and' ) {
	global $wp_post_statuses;

	$field = ('names' == $output) ? 'name' : false;

	return wp_filter_object_list($wp_post_statuses, $args, $operator, $field);
}

/**
 * Whether the post type is hierarchical.
 *
 * A false return value might also mean that the post type does not exist.
 *
 * @since 3.0.0
 * @see get_post_type_object
 *
 * @param string $post_type Post type name
 * @return bool Whether post type is hierarchical.
 */
function is_post_type_hierarchical( $post_type ) {
	if ( ! post_type_exists( $post_type ) )
		return false;

	$post_type = get_post_type_object( $post_type );
	return $post_type->hierarchical;
}

/**
 * Checks if a post type is registered.
 *
 * @since 3.0.0
 * @uses get_post_type_object()
 *
 * @param string $post_type Post type name
 * @return bool Whether post type is registered.
 */
function post_type_exists( $post_type ) {
	return (bool) get_post_type_object( $post_type );
}

/**
 * Retrieve the post type of the current post or of a given post.
 *
 * @since 2.1.0
 *
 * @uses $post The Loop current post global
 *
 * @param mixed $the_post Optional. Post object or post ID.
 * @return bool|string post type or false on failure.
 */
function get_post_type( $the_post = false ) {
	global $post;

	if ( false === $the_post )
		$the_post = $post;
	elseif ( is_numeric($the_post) )
		$the_post = get_post($the_post);

	if ( is_object($the_post) )
		return $the_post->post_type;

	return false;
}

/**
 * Retrieve a post type object by name
 *
 * @package WordPress
 * @subpackage Post
 * @since 3.0.0
 * @uses $wp_post_types
 * @see register_post_type
 * @see get_post_types
 *
 * @param string $post_type The name of a registered post type
 * @return object A post type object
 */
function get_post_type_object( $post_type ) {
	global $wp_post_types;

	if ( empty($wp_post_types[$post_type]) )
		return null;

	return $wp_post_types[$post_type];
}

/**
 * Get a list of all registered post type objects.
 *
 * @package WordPress
 * @subpackage Post
 * @since 2.9.0
 * @uses $wp_post_types
 * @see register_post_type
 *
 * @param array|string $args An array of key => value arguments to match against the post type objects.
 * @param string $output The type of output to return, either post type 'names' or 'objects'. 'names' is the default.
 * @param string $operator The logical operation to perform. 'or' means only one element
 *  from the array needs to match; 'and' means all elements must match. The default is 'and'.
 * @return array A list of post type names or objects
 */
function get_post_types( $args = array(), $output = 'names', $operator = 'and' ) {
	global $wp_post_types;

	$field = ('names' == $output) ? 'name' : false;

	return wp_filter_object_list($wp_post_types, $args, $operator, $field);
}

/**
 * Register a post type. Do not use before init.
 *
 * A function for creating or modifying a post type based on the
 * parameters given. The function will accept an array (second optional
 * parameter), along with a string for the post type name.
 *
 * Optional $args contents:
 *
 * - label - Name of the post type shown in the menu. Usually plural. If not set, labels['name'] will be used.
 * - description - A short descriptive summary of what the post type is. Defaults to blank.
 * - public - Whether posts of this type should be shown in the admin UI. Defaults to false.
 * - exclude_from_search - Whether to exclude posts with this post type from search results.
 *     Defaults to true if the type is not public, false if the type is public.
 * - publicly_queryable - Whether post_type queries can be performed from the front page.
 *     Defaults to whatever public is set as.
 * - show_ui - Whether to generate a default UI for managing this post type. Defaults to true
 *     if the type is public, false if the type is not public.
 * - show_in_menu - Where to show the post type in the admin menu. True for a top level menu,
 *     false for no menu, or can be a top level page like 'tools.php' or 'edit.php?post_type=page'.
 *     show_ui must be true.
 * - menu_position - The position in the menu order the post type should appear. Defaults to the bottom.
 * - menu_icon - The url to the icon to be used for this menu. Defaults to use the posts icon.
 * - capability_type - The string to use to build the read, edit, and delete capabilities. Defaults to 'post'.
 *   May be passed as an array to allow for alternative plurals when using this argument as a base to construct the
 *   capabilities, e.g. array('story', 'stories').
 * - capabilities - Array of capabilities for this post type. By default the capability_type is used
 *      as a base to construct capabilities. You can see accepted values in {@link get_post_type_capabilities()}.
 * - map_meta_cap - Whether to use the internal default meta capability handling. Defaults to false.
 * - hierarchical - Whether the post type is hierarchical. Defaults to false.
 * - supports - An alias for calling add_post_type_support() directly. See {@link add_post_type_support()}
 *     for documentation. Defaults to none.
 * - register_meta_box_cb - Provide a callback function that will be called when setting up the
 *     meta boxes for the edit form. Do remove_meta_box() and add_meta_box() calls in the callback.
 * - taxonomies - An array of taxonomy identifiers that will be registered for the post type.
 *     Default is no taxonomies. Taxonomies can be registered later with register_taxonomy() or
 *     register_taxonomy_for_object_type().
 * - labels - An array of labels for this post type. By default post labels are used for non-hierarchical
 *     types and page labels for hierarchical ones. You can see accepted values in {@link get_post_type_labels()}.
 * - has_archive - True to enable post type archives. Will generate the proper rewrite rules if rewrite is enabled.
 * - rewrite - false to prevent rewrite. Defaults to true. Use array('slug'=>$slug) to customize permastruct;
 *     default will use $post_type as slug. Other options include 'with_front', 'feeds', 'pages', and 'ep_mask'.
 * - query_var - false to prevent queries, or string to value of the query var to use for this post type
 * - can_export - true allows this post type to be exported.
 * - show_in_nav_menus - true makes this post type available for selection in navigation menus.
 * - _builtin - true if this post type is a native or "built-in" post_type. THIS IS FOR INTERNAL USE ONLY!
 * - _edit_link - URL segement to use for edit link of this post type. THIS IS FOR INTERNAL USE ONLY!
 *
 * @since 2.9.0
 * @uses $wp_post_types Inserts new post type object into the list
 *
 * @param string $post_type Name of the post type.
 * @param array|string $args See above description.
 * @return object|WP_Error the registered post type object, or an error object
 */
function register_post_type($post_type, $args = array()) {
	global $wp_post_types, $wp_rewrite, $wp;

	if ( !is_array($wp_post_types) )
		$wp_post_types = array();

	// Args prefixed with an underscore are reserved for internal use.
	$defaults = array(
		'labels' => array(), 'description' => '', 'publicly_queryable' => null, 'exclude_from_search' => null,
		'capability_type' => 'post', 'capabilities' => array(), 'map_meta_cap' => null,
		'_builtin' => false, '_edit_link' => 'post.php?post=%d', 'hierarchical' => false,
		'public' => false, 'rewrite' => true, 'has_archive' => false, 'query_var' => true,
		'supports' => array(), 'register_meta_box_cb' => null,
		'taxonomies' => array(), 'show_ui' => null, 'menu_position' => null, 'menu_icon' => null,
		'can_export' => true,
		'show_in_nav_menus' => null, 'show_in_menu' => null, 'show_in_admin_bar' => null,
	);
	$args = wp_parse_args($args, $defaults);
	$args = (object) $args;

	$post_type = sanitize_key($post_type);
	$args->name = $post_type;

	if ( strlen( $post_type ) > 20 )
			return new WP_Error( 'post_type_too_long', __( 'Post types cannot exceed 20 characters in length' ) );

	// If not set, default to the setting for public.
	if ( null === $args->publicly_queryable )
		$args->publicly_queryable = $args->public;

	// If not set, default to the setting for public.
	if ( null === $args->show_ui )
		$args->show_ui = $args->public;

	// If not set, default to the setting for show_ui.
	if ( null === $args->show_in_menu || ! $args->show_ui )
		$args->show_in_menu = $args->show_ui;

	// If not set, default to the whether the full UI is shown.
	if ( null === $args->show_in_admin_bar )
		$args->show_in_admin_bar = true === $args->show_in_menu;

	// Whether to show this type in nav-menus.php. Defaults to the setting for public.
	if ( null === $args->show_in_nav_menus )
		$args->show_in_nav_menus = $args->public;

	// If not set, default to true if not public, false if public.
	if ( null === $args->exclude_from_search )
		$args->exclude_from_search = !$args->public;

	// Back compat with quirky handling in version 3.0. #14122
	if ( empty( $args->capabilities ) && null === $args->map_meta_cap && in_array( $args->capability_type, array( 'post', 'page' ) ) )
		$args->map_meta_cap = true;

	if ( null === $args->map_meta_cap )
		$args->map_meta_cap = false;

	$args->cap = get_post_type_capabilities( $args );
	unset($args->capabilities);

	if ( is_array( $args->capability_type ) )
		$args->capability_type = $args->capability_type[0];

	if ( ! empty($args->supports) ) {
		add_post_type_support($post_type, $args->supports);
		unset($args->supports);
	} else {
		// Add default features
		add_post_type_support($post_type, array('title', 'editor'));
	}

	if ( false !== $args->query_var && !empty($wp) ) {
		if ( true === $args->query_var )
			$args->query_var = $post_type;
		$args->query_var = sanitize_title_with_dashes($args->query_var);
		$wp->add_query_var($args->query_var);
	}

	if ( false !== $args->rewrite && ( is_admin() || '' != get_option('permalink_structure') ) ) {
		if ( ! is_array( $args->rewrite ) )
			$args->rewrite = array();
		if ( empty( $args->rewrite['slug'] ) )
			$args->rewrite['slug'] = $post_type;
		if ( ! isset( $args->rewrite['with_front'] ) )
			$args->rewrite['with_front'] = true;
		if ( ! isset( $args->rewrite['pages'] ) )
			$args->rewrite['pages'] = true;
		if ( ! isset( $args->rewrite['feeds'] ) || ! $args->has_archive )
			$args->rewrite['feeds'] = (bool) $args->has_archive;
		if ( ! isset( $args->rewrite['ep_mask'] ) ) {
			if ( isset( $args->permalink_epmask ) )
				$args->rewrite['ep_mask'] = $args->permalink_epmask;
			else
				$args->rewrite['ep_mask'] = EP_PERMALINK;
		}

		if ( $args->hierarchical )
			add_rewrite_tag("%$post_type%", '(.+?)', $args->query_var ? "{$args->query_var}=" : "post_type=$post_type&name=");
		else
			add_rewrite_tag("%$post_type%", '([^/]+)', $args->query_var ? "{$args->query_var}=" : "post_type=$post_type&name=");

		if ( $args->has_archive ) {
			$archive_slug = $args->has_archive === true ? $args->rewrite['slug'] : $args->has_archive;
			if ( $args->rewrite['with_front'] )
				$archive_slug = substr( $wp_rewrite->front, 1 ) . $archive_slug;
			else
				$archive_slug = $wp_rewrite->root . $archive_slug;

			add_rewrite_rule( "{$archive_slug}/?$", "index.php?post_type=$post_type", 'top' );
			if ( $args->rewrite['feeds'] && $wp_rewrite->feeds ) {
				$feeds = '(' . trim( implode( '|', $wp_rewrite->feeds ) ) . ')';
				add_rewrite_rule( "{$archive_slug}/feed/$feeds/?$", "index.php?post_type=$post_type" . '&feed=$matches[1]', 'top' );
				add_rewrite_rule( "{$archive_slug}/$feeds/?$", "index.php?post_type=$post_type" . '&feed=$matches[1]', 'top' );
			}
			if ( $args->rewrite['pages'] )
				add_rewrite_rule( "{$archive_slug}/{$wp_rewrite->pagination_base}/([0-9]{1,})/?$", "index.php?post_type=$post_type" . '&paged=$matches[1]', 'top' );
		}

		add_permastruct( $post_type, "{$args->rewrite['slug']}/%$post_type%", $args->rewrite );
	}

	if ( $args->register_meta_box_cb )
		add_action('add_meta_boxes_' . $post_type, $args->register_meta_box_cb, 10, 1);

	$args->labels = get_post_type_labels( $args );
	$args->label = $args->labels->name;

	$wp_post_types[$post_type] = $args;

	add_action( 'future_' . $post_type, '_future_post_hook', 5, 2 );

	foreach ( $args->taxonomies as $taxonomy ) {
		register_taxonomy_for_object_type( $taxonomy, $post_type );
	}

	do_action( 'registered_post_type', $post_type, $args );

	return $args;
}

/**
 * Builds an object with all post type capabilities out of a post type object
 *
 * Post type capabilities use the 'capability_type' argument as a base, if the
 * capability is not set in the 'capabilities' argument array or if the
 * 'capabilities' argument is not supplied.
 *
 * The capability_type argument can optionally be registered as an array, with
 * the first value being singular and the second plural, e.g. array('story, 'stories')
 * Otherwise, an 's' will be added to the value for the plural form. After
 * registration, capability_type will always be a string of the singular value.
 *
 * By default, seven keys are accepted as part of the capabilities array:
 *
 * - edit_post, read_post, and delete_post are meta capabilities, which are then
 *   generally mapped to corresponding primitive capabilities depending on the
 *   context, which would be the post being edited/read/deleted and the user or
 *   role being checked. Thus these capabilities would generally not be granted
 *   directly to users or roles.
 *
 * - edit_posts - Controls whether objects of this post type can be edited.
 * - edit_others_posts - Controls whether objects of this type owned by other users
 *   can be edited. If the post type does not support an author, then this will
 *   behave like edit_posts.
 * - publish_posts - Controls publishing objects of this post type.
 * - read_private_posts - Controls whether private objects can be read.
 *
 * These four primitive capabilities are checked in core in various locations.
 * There are also seven other primitive capabilities which are not referenced
 * directly in core, except in map_meta_cap(), which takes the three aforementioned
 * meta capabilities and translates them into one or more primitive capabilities
 * that must then be checked against the user or role, depending on the context.
 *
 * - read - Controls whether objects of this post type can be read.
 * - delete_posts - Controls whether objects of this post type can be deleted.
 * - delete_private_posts - Controls whether private objects can be deleted.
 * - delete_published_posts - Controls whether published objects can be deleted.
 * - delete_others_posts - Controls whether objects owned by other users can be
 *   can be deleted. If the post type does not support an author, then this will
 *   behave like delete_posts.
 * - edit_private_posts - Controls whether private objects can be edited.
 * - edit_published_posts - Controls whether published objects can be edited.
 *
 * These additional capabilities are only used in map_meta_cap(). Thus, they are
 * only assigned by default if the post type is registered with the 'map_meta_cap'
 * argument set to true (default is false).
 *
 * @see map_meta_cap()
 * @since 3.0.0
 *
 * @param object $args Post type registration arguments
 * @return object object with all the capabilities as member variables
 */
function get_post_type_capabilities( $args ) {
	if ( ! is_array( $args->capability_type ) )
		$args->capability_type = array( $args->capability_type, $args->capability_type . 's' );

	// Singular base for meta capabilities, plural base for primitive capabilities.
	list( $singular_base, $plural_base ) = $args->capability_type;

	$default_capabilities = array(
		// Meta capabilities
		'edit_post'          => 'edit_'         . $singular_base,
		'read_post'          => 'read_'         . $singular_base,
		'delete_post'        => 'delete_'       . $singular_base,
		// Primitive capabilities used outside of map_meta_cap():
		'edit_posts'         => 'edit_'         . $plural_base,
		'edit_others_posts'  => 'edit_others_'  . $plural_base,
		'publish_posts'      => 'publish_'      . $plural_base,
		'read_private_posts' => 'read_private_' . $plural_base,
	);

	// Primitive capabilities used within map_meta_cap():
	if ( $args->map_meta_cap ) {
		$default_capabilities_for_mapping = array(
			'read'                   => 'read',
			'delete_posts'           => 'delete_'           . $plural_base,
			'delete_private_posts'   => 'delete_private_'   . $plural_base,
			'delete_published_posts' => 'delete_published_' . $plural_base,
			'delete_others_posts'    => 'delete_others_'    . $plural_base,
			'edit_private_posts'     => 'edit_private_'     . $plural_base,
			'edit_published_posts'   => 'edit_published_'   . $plural_base,
		);
		$default_capabilities = array_merge( $default_capabilities, $default_capabilities_for_mapping );
	}

	$capabilities = array_merge( $default_capabilities, $args->capabilities );

	// Remember meta capabilities for future reference.
	if ( $args->map_meta_cap )
		_post_type_meta_capabilities( $capabilities );

	return (object) $capabilities;
}

/**
 * Stores or returns a list of post type meta caps for map_meta_cap().
 *
 * @since 3.1.0
 * @access private
 */
function _post_type_meta_capabilities( $capabilities = null ) {
	static $meta_caps = array();
	if ( null === $capabilities )
		return $meta_caps;
	foreach ( $capabilities as $core => $custom ) {
		if ( in_array( $core, array( 'read_post', 'delete_post', 'edit_post' ) ) )
			$meta_caps[ $custom ] = $core;
	}
}

/**
 * Builds an object with all post type labels out of a post type object
 *
 * Accepted keys of the label array in the post type object:
 * - name - general name for the post type, usually plural. The same and overridden by $post_type_object->label. Default is Posts/Pages
 * - singular_name - name for one object of this post type. Default is Post/Page
 * - add_new - Default is Add New for both hierarchical and non-hierarchical types. When internationalizing this string, please use a {@link http://codex.wordpress.org/I18n_for_WordPress_Developers#Disambiguation_by_context gettext context} matching your post type. Example: <code>_x('Add New', 'product');</code>
 * - add_new_item - Default is Add New Post/Add New Page
 * - edit_item - Default is Edit Post/Edit Page
 * - new_item - Default is New Post/New Page
 * - view_item - Default is View Post/View Page
 * - search_items - Default is Search Posts/Search Pages
 * - not_found - Default is No posts found/No pages found
 * - not_found_in_trash - Default is No posts found in Trash/No pages found in Trash
 * - parent_item_colon - This string isn't used on non-hierarchical types. In hierarchical ones the default is Parent Page:
 * - all_items - String for the submenu. Default is All Posts/All Pages
 * - menu_name - Default is the same as <code>name</code>
 *
 * Above, the first default value is for non-hierarchical post types (like posts) and the second one is for hierarchical post types (like pages).
 *
 * @since 3.0.0
 * @param object $post_type_object
 * @return object object with all the labels as member variables
 */
function get_post_type_labels( $post_type_object ) {
	$nohier_vs_hier_defaults = array(
		'name' => array( _x('Posts', 'post type general name'), _x('Pages', 'post type general name') ),
		'singular_name' => array( _x('Post', 'post type singular name'), _x('Page', 'post type singular name') ),
		'add_new' => array( _x('Add New', 'post'), _x('Add New', 'page') ),
		'add_new_item' => array( __('Add New Post'), __('Add New Page') ),
		'edit_item' => array( __('Edit Post'), __('Edit Page') ),
		'new_item' => array( __('New Post'), __('New Page') ),
		'view_item' => array( __('View Post'), __('View Page') ),
		'search_items' => array( __('Search Posts'), __('Search Pages') ),
		'not_found' => array( __('No posts found.'), __('No pages found.') ),
		'not_found_in_trash' => array( __('No posts found in Trash.'), __('No pages found in Trash.') ),
		'parent_item_colon' => array( null, __('Parent Page:') ),
		'all_items' => array( __( 'All Posts' ), __( 'All Pages' ) )
	);
	$nohier_vs_hier_defaults['menu_name'] = $nohier_vs_hier_defaults['name'];
	return _get_custom_object_labels( $post_type_object, $nohier_vs_hier_defaults );
}

/**
 * Builds an object with custom-something object (post type, taxonomy) labels out of a custom-something object
 *
 * @access private
 * @since 3.0.0
 */
function _get_custom_object_labels( $object, $nohier_vs_hier_defaults ) {

	if ( isset( $object->label ) && empty( $object->labels['name'] ) )
		$object->labels['name'] = $object->label;

	if ( !isset( $object->labels['singular_name'] ) && isset( $object->labels['name'] ) )
		$object->labels['singular_name'] = $object->labels['name'];

	if ( ! isset( $object->labels['name_admin_bar'] ) )
		$object->labels['name_admin_bar'] = isset( $object->labels['singular_name'] ) ? $object->labels['singular_name'] : $object->name;

	if ( !isset( $object->labels['menu_name'] ) && isset( $object->labels['name'] ) )
		$object->labels['menu_name'] = $object->labels['name'];

	if ( !isset( $object->labels['all_items'] ) && isset( $object->labels['menu_name'] ) )
		$object->labels['all_items'] = $object->labels['menu_name'];

	foreach ( $nohier_vs_hier_defaults as $key => $value )
			$defaults[$key] = $object->hierarchical ? $value[1] : $value[0];

	$labels = array_merge( $defaults, $object->labels );
	return (object)$labels;
}

/**
 * Adds submenus for post types.
 *
 * @access private
 * @since 3.1.0
 */
function _add_post_type_submenus() {
	foreach ( get_post_types( array( 'show_ui' => true ) ) as $ptype ) {
		$ptype_obj = get_post_type_object( $ptype );
		// Submenus only.
		if ( ! $ptype_obj->show_in_menu || $ptype_obj->show_in_menu === true )
			continue;
		add_submenu_page( $ptype_obj->show_in_menu, $ptype_obj->labels->name, $ptype_obj->labels->all_items, $ptype_obj->cap->edit_posts, "edit.php?post_type=$ptype" );
	}
}
add_action( 'admin_menu', '_add_post_type_submenus' );

/**
 * Register support of certain features for a post type.
 *
 * All features are directly associated with a functional area of the edit screen, such as the
 * editor or a meta box: 'title', 'editor', 'comments', 'revisions', 'trackbacks', 'author',
 * 'excerpt', 'page-attributes', 'thumbnail', and 'custom-fields'.
 *
 * Additionally, the 'revisions' feature dictates whether the post type will store revisions,
 * and the 'comments' feature dictates whether the comments count will show on the edit screen.
 *
 * @since 3.0.0
 * @param string $post_type The post type for which to add the feature
 * @param string|array $feature the feature being added, can be an array of feature strings or a single string
 */
function add_post_type_support( $post_type, $feature ) {
	global $_wp_post_type_features;

	$features = (array) $feature;
	foreach ($features as $feature) {
		if ( func_num_args() == 2 )
			$_wp_post_type_features[$post_type][$feature] = true;
		else
			$_wp_post_type_features[$post_type][$feature] = array_slice( func_get_args(), 2 );
	}
}

/**
 * Remove support for a feature from a post type.
 *
 * @since 3.0.0
 * @param string $post_type The post type for which to remove the feature
 * @param string $feature The feature being removed
 */
function remove_post_type_support( $post_type, $feature ) {
	global $_wp_post_type_features;

	if ( !isset($_wp_post_type_features[$post_type]) )
		return;

	if ( isset($_wp_post_type_features[$post_type][$feature]) )
		unset($_wp_post_type_features[$post_type][$feature]);
}

/**
 * Get all the post type features
 *
 * @since 3.4.0
 * @param string $post_type The post type
 * @return array
 */

function get_all_post_type_supports( $post_type ) {
	global $_wp_post_type_features;

	if ( isset( $_wp_post_type_features[$post_type] ) )
		return $_wp_post_type_features[$post_type];

	return array();
}

/**
 * Checks a post type's support for a given feature
 *
 * @since 3.0.0
 * @param string $post_type The post type being checked
 * @param string $feature the feature being checked
 * @return boolean
 */

function post_type_supports( $post_type, $feature ) {
	global $_wp_post_type_features;

	if ( !isset( $_wp_post_type_features[$post_type][$feature] ) )
		return false;

	// If no args passed then no extra checks need be performed
	if ( func_num_args() <= 2 )
		return true;

	// @todo Allow pluggable arg checking
	//$args = array_slice( func_get_args(), 2 );

	return true;
}

/**
 * Updates the post type for the post ID.
 *
 * The page or post cache will be cleaned for the post ID.
 *
 * @since 2.5.0
 *
 * @uses $wpdb
 *
 * @param int $post_id Post ID to change post type. Not actually optional.
 * @param string $post_type Optional, default is post. Supported values are 'post' or 'page' to
 *  name a few.
 * @return int Amount of rows changed. Should be 1 for success and 0 for failure.
 */
function set_post_type( $post_id = 0, $post_type = 'post' ) {
	global $wpdb;

	$post_type = sanitize_post_field('post_type', $post_type, $post_id, 'db');
	$return = $wpdb->update( $wpdb->posts, array('post_type' => $post_type), array('ID' => $post_id) );

	clean_post_cache( $post_id );

	return $return;
}

/**
 * Retrieve list of latest posts or posts matching criteria.
 *
 * The defaults are as follows:
 *     'numberposts' - Default is 5. Total number of posts to retrieve.
 *     'offset' - Default is 0. See {@link WP_Query::query()} for more.
 *     'category' - What category to pull the posts from.
 *     'orderby' - Default is 'post_date'. How to order the posts.
 *     'order' - Default is 'DESC'. The order to retrieve the posts.
 *     'include' - See {@link WP_Query::query()} for more.
 *     'exclude' - See {@link WP_Query::query()} for more.
 *     'meta_key' - See {@link WP_Query::query()} for more.
 *     'meta_value' - See {@link WP_Query::query()} for more.
 *     'post_type' - Default is 'post'. Can be 'page', or 'attachment' to name a few.
 *     'post_parent' - The parent of the post or post type.
 *     'post_status' - Default is 'publish'. Post status to retrieve.
 *
 * @since 1.2.0
 * @uses $wpdb
 * @uses WP_Query::query() See for more default arguments and information.
 * @link http://codex.wordpress.org/Template_Tags/get_posts
 *
 * @param array $args Optional. Overrides defaults.
 * @return array List of posts.
 */
function get_posts($args = null) {
	$defaults = array(
		'numberposts' => 5, 'offset' => 0,
		'category' => 0, 'orderby' => 'post_date',
		'order' => 'DESC', 'include' => array(),
		'exclude' => array(), 'meta_key' => '',
		'meta_value' =>'', 'post_type' => 'post',
		'suppress_filters' => true
	);

	$r = wp_parse_args( $args, $defaults );
	if ( empty( $r['post_status'] ) )
		$r['post_status'] = ( 'attachment' == $r['post_type'] ) ? 'inherit' : 'publish';
	if ( ! empty($r['numberposts']) && empty($r['posts_per_page']) )
		$r['posts_per_page'] = $r['numberposts'];
	if ( ! empty($r['category']) )
		$r['cat'] = $r['category'];
	if ( ! empty($r['include']) ) {
		$incposts = wp_parse_id_list( $r['include'] );
		$r['posts_per_page'] = count($incposts);  // only the number of posts included
		$r['post__in'] = $incposts;
	} elseif ( ! empty($r['exclude']) )
		$r['post__not_in'] = wp_parse_id_list( $r['exclude'] );

	$r['ignore_sticky_posts'] = true;
	$r['no_found_rows'] = true;

	$get_posts = new WP_Query;
	return $get_posts->query($r);

}

//
// Post meta functions
//

/**
 * Add meta data field to a post.
 *
 * Post meta data is called "Custom Fields" on the Administration Screen.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/add_post_meta
 *
 * @param int $post_id Post ID.
 * @param string $meta_key Metadata name.
 * @param mixed $meta_value Metadata value.
 * @param bool $unique Optional, default is false. Whether the same key should not be added.
 * @return bool False for failure. True for success.
 */
function add_post_meta($post_id, $meta_key, $meta_value, $unique = false) {
	// make sure meta is added to the post, not a revision
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	return add_metadata('post', $post_id, $meta_key, $meta_value, $unique);
}

/**
 * Remove metadata matching criteria from a post.
 *
 * You can match based on the key, or key and value. Removing based on key and
 * value, will keep from removing duplicate metadata with the same key. It also
 * allows removing all metadata matching key, if needed.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/delete_post_meta
 *
 * @param int $post_id post ID
 * @param string $meta_key Metadata name.
 * @param mixed $meta_value Optional. Metadata value.
 * @return bool False for failure. True for success.
 */
function delete_post_meta($post_id, $meta_key, $meta_value = '') {
	// make sure meta is added to the post, not a revision
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	return delete_metadata('post', $post_id, $meta_key, $meta_value);
}

/**
 * Retrieve post meta field for a post.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/get_post_meta
 *
 * @param int $post_id Post ID.
 * @param string $key Optional. The meta key to retrieve. By default, returns data for all keys.
 * @param bool $single Whether to return a single value.
 * @return mixed Will be an array if $single is false. Will be value of meta data field if $single
 *  is true.
 */
function get_post_meta($post_id, $key = '', $single = false) {
	return get_metadata('post', $post_id, $key, $single);
}

/**
 * Update post meta field based on post ID.
 *
 * Use the $prev_value parameter to differentiate between meta fields with the
 * same key and post ID.
 *
 * If the meta field for the post does not exist, it will be added.
 *
 * @since 1.5.0
 * @uses $wpdb
 * @link http://codex.wordpress.org/Function_Reference/update_post_meta
 *
 * @param int $post_id Post ID.
 * @param string $meta_key Metadata key.
 * @param mixed $meta_value Metadata value.
 * @param mixed $prev_value Optional. Previous value to check before removing.
 * @return bool False on failure, true if success.
 */
function update_post_meta($post_id, $meta_key, $meta_value, $prev_value = '') {
	// make sure meta is added to the post, not a revision
	if ( $the_post = wp_is_post_revision($post_id) )
		$post_id = $the_post;

	return update_metadata('post', $post_id, $meta_key, $meta_value, $prev_value);
}

/**
 * Delete everything from post meta matching meta key.
 *
 * @since 2.3.0
 * @uses $wpdb
 *
 * @param string $post_meta_key Key to search for when deleting.
 * @return bool Whether the post meta key was deleted from the database
 */
function delete_post_meta_by_key($post_meta_key) {
	return delete_metadata( 'post', null, $post_meta_key, '', true );
}

/**
 * Retrieve post meta fields, based on post ID.
 *
 * The post meta fields are retrieved from the cache where possible,
 * so the function is optimized to be called more than once.
 *
 * @since 1.2.0
 * @link http://codex.wordpress.org/Function_Reference/get_post_custom
 *
 * @param int $post_id Post ID.
 * @return array
 */
function get_post_custom( $post_id = 0 ) {
	$post_id = absint( $post_id );
	if ( ! $post_id )
		$post_id = get_the_ID();

	return get_post_meta( $post_id );
}

/**
 * Retrieve meta field names for a post.
 *
 * If there are no meta fields, then nothing (null) will be returned.
 *
 * @since 1.2.0
 * @link http://codex.wordpress.org/Function_Reference/get_post_custom_keys
 *
 * @param int $post_id post ID
 * @return array|null Either array of the keys, or null if keys could not be retrieved.
 */
function get_post_custom_keys( $post_id = 0 ) {
	$custom = get_post_custom( $post_id );

	if ( !is_array($custom) )
		return;

	if ( $keys = array_keys($custom) )
		return $keys;
}

/**
 * Retrieve values for a custom post field.
 *
 * The parameters must not be considered optional. All of the post meta fields
 * will be retrieved and only the meta field key values returned.
 *
 * @since 1.2.0
 * @link http://codex.wordpress.org/Function_Reference/get_post_custom_values
 *
 * @param string $key Meta field key.
 * @param int $post_id Post ID
 * @return array Meta field values.
 */
function get_post_custom_values( $key = '', $post_id = 0 ) {
	if ( !$key )
		return null;

	$custom = get_post_custom($post_id);

	return isset($custom[$key]) ? $custom[$key] : null;
}

/**
 * Check if post is sticky.
 *
 * Sticky posts should remain at the top of The Loop. If the post ID is not
 * given, then The Loop ID for the current post will be used.
 *
 * @since 2.7.0
 *
 * @param int $post_id Optional. Post ID.
 * @return bool Whether post is sticky.
 */
function is_sticky( $post_id = 0 ) {
	$post_id = absint( $post_id );

	if ( ! $post_id )
		$post_id = get_the_ID();

	$stickies = get_option( 'sticky_posts' );

	if ( ! is_array( $stickies ) )
		return false;

	if ( in_array( $post_id, $stickies ) )
		return true;

	return false;
}

/**
 * Sanitize every post field.
 *
 * If the context is 'raw', then the post object or array will get minimal santization of the int fields.
 *
 * @since 2.3.0
 * @uses sanitize_post_field() Used to sanitize the fields.
 *
 * @param object|array $post The Post Object or Array
 * @param string $context Optional, default is 'display'. How to sanitize post fields.
 * @return object|array The now sanitized Post Object or Array (will be the same type as $post)
 */
function sanitize_post($post, $context = 'display') {
	if ( is_object($post) ) {
		// Check if post already filtered for this context
		if ( isset($post->filter) && $context == $post->filter )
			return $post;
		if ( !isset($post->ID) )
			$post->ID = 0;
		foreach ( array_keys(get_object_vars($post)) as $field )
			$post->$field = sanitize_post_field($field, $post->$field, $post->ID, $context);
		$post->filter = $context;
	} else {
		// Check if post already filtered for this context
		if ( isset($post['filter']) && $context == $post['filter'] )
			return $post;
		if ( !isset($post['ID']) )
			$post['ID'] = 0;
		foreach ( array_keys($post) as $field )
			$post[$field] = sanitize_post_field($field, $post[$field], $post['ID'], $context);
		$post['filter'] = $context;
	}
	return $post;
}

/**
 * Sanitize post field based on context.
 *
 * Possible context values are:  'raw', 'edit', 'db', 'display', 'attribute' and 'js'. The
 * 'display' context is used by default. 'attribute' and 'js' contexts are treated like 'display'
 * when calling filters.
 *
 * @since 2.3.0
 * @uses apply_filters() Calls 'edit_$field' and '{$field_no_prefix}_edit_pre' passing $value and
 *  $post_id if $context == 'edit' and field name prefix == 'post_'.
 *
 * @uses apply_filters() Calls 'edit_post_$field' passing $value and $post_id if $context == 'db'.
 * @uses apply_filters() Calls 'pre_$field' passing $value if $context == 'db' and field name prefix == 'post_'.
 * @uses apply_filters() Calls '{$field}_pre' passing $value if $context == 'db' and field name prefix != 'post_'.
 *
 * @uses apply_filters() Calls '$field' passing $value, $post_id and $context if $context == anything
 *  other than 'raw', 'edit' and 'db' and field name prefix == 'post_'.
 * @uses apply_filters() Calls 'post_$field' passing $value if $context == anything other than 'raw',
 *  'edit' and 'db' and field name prefix != 'post_'.
 *
 * @param string $field The Post Object field name.
 * @param mixed $value The Post Object value.
 * @param int $post_id Post ID.
 * @param string $context How to sanitize post fields. Looks for 'raw', 'edit', 'db', 'display',
 *               'attribute' and 'js'.
 * @return mixed Sanitized value.
 */
function sanitize_post_field($field, $value, $post_id, $context) {
	$int_fields = array('ID', 'post_parent', 'menu_order');
	if ( in_array($field, $int_fields) )
		$value = (int) $value;

	// Fields which contain arrays of ints.
	$array_int_fields = array( 'ancestors' );
	if ( in_array($field, $array_int_fields) ) {
		$value = array_map( 'absint', $value);
		return $value;
	}

	if ( 'raw' == $context )
		return $value;

	$prefixed = false;
	if ( false !== strpos($field, 'post_') ) {
		$prefixed = true;
		$field_no_prefix = str_replace('post_', '', $field);
	}

	if ( 'edit' == $context ) {
		$format_to_edit = array('post_content', 'post_excerpt', 'post_title', 'post_password');

		if ( $prefixed ) {
			$value = apply_filters("edit_{$field}", $value, $post_id);
			// Old school
			$value = apply_filters("{$field_no_prefix}_edit_pre", $value, $post_id);
		} else {
			$value = apply_filters("edit_post_{$field}", $value, $post_id);
		}

		if ( in_array($field, $format_to_edit) ) {
			if ( 'post_content' == $field )
				$value = format_to_edit($value, user_can_richedit());
			else
				$value = format_to_edit($value);
		} else {
			$value = esc_attr($value);
		}
	} else if ( 'db' == $context ) {
		if ( $prefixed ) {
			$value = apply_filters("pre_{$field}", $value);
			$value = apply_filters("{$field_no_prefix}_save_pre", $value);
		} else {
			$value = apply_filters("pre_post_{$field}", $value);
			$value = apply_filters("{$field}_pre", $value);
		}
	} else {
		// Use display filters by default.
		if ( $prefixed )
			$value = apply_filters($field, $value, $post_id, $context);
		else
			$value = apply_filters("post_{$field}", $value, $post_id, $context);
	}

	if ( 'attribute' == $context )
		$value = esc_attr($value);
	else if ( 'js' == $context )
		$value = esc_js($value);

	return $value;
}

/**
 * Make a post sticky.
 *
 * Sticky posts should be displayed at the top of the front page.
 *
 * @since 2.7.0
 *
 * @param int $post_id Post ID.
 */
function stick_post($post_id) {
	$stickies = get_option('sticky_posts');

	if ( !is_array($stickies) )
		$stickies = array($post_id);

	if ( ! in_array($post_id, $stickies) )
		$stickies[] = $post_id;

	update_option('sticky_posts', $stickies);
}

/**
 * Unstick a post.
 *
 * Sticky posts should be displayed at the top of the front page.
 *
 * @since 2.7.0
 *
 * @param int $post_id Post ID.
 */
function unstick_post($post_id) {
	$stickies = get_option('sticky_posts');

	if ( !is_array($stickies) )
		return;

	if ( ! in_array($post_id, $stickies) )
		return;

	$offset = array_search($post_id, $stickies);
	if ( false === $offset )
		return;

	array_splice($stickies, $offset, 1);

	update_option('sticky_posts', $stickies);
}

/**
 * Count number of posts of a post type and is user has permissions to view.
 *
 * This function provides an efficient method of finding the amount of post's
 * type a blog has. Another method is to count the amount of items in
 * get_posts(), but that method has a lot of overhead with doing so. Therefore,
 * when developing for 2.5+, use this function instead.
 *
 * The $perm parameter checks for 'readable' value and if the user can read
 * private posts, it will display that for the user that is signed in.
 *
 * @since 2.5.0
 * @link http://codex.wordpress.org/Template_Tags/wp_count_posts
 *
 * @param string $type Optional. Post type to retrieve count
 * @param string $perm Optional. 'readable' or empty.
 * @return object Number of posts for each status
 */
function wp_count_posts( $type = 'post', $perm = '' ) {
	global $wpdb;

	$user = wp_get_current_user();

	$cache_key = $type;

	$query = "SELECT post_status, COUNT( * ) AS num_posts FROM {$wpdb->posts} WHERE post_type = %s";
	if ( 'readable' == $perm && is_user_logged_in() ) {
		$post_type_object = get_post_type_object($type);
		if ( !current_user_can( $post_type_object->cap->read_private_posts ) ) {
			$cache_key .= '_' . $perm . '_' . $user->ID;
			$query .= " AND (post_status != 'private' OR ( post_author = '$user->ID' AND post_status = 'private' ))";
		}
	}
	$query .= ' GROUP BY post_status';

	$count = wp_cache_get($cache_key, 'counts');
	if ( false !== $count )
		return $count;

	$count = $wpdb->get_results( $wpdb->prepare( $query, $type ), ARRAY_A );

	$stats = array();
	foreach ( get_post_stati() as $state )
		$stats[$state] = 0;

	foreach ( (array) $count as $row )
		$stats[$row['post_status']] = $row['num_posts'];

	$stats = (object) $stats;
	wp_cache_set($cache_key, $stats, 'counts');

	return $stats;
}

/**
 * Count number of attachments for the mime type(s).
 *
 * If you set the optional mime_type parameter, then an array will still be
 * returned, but will only have the item you are looking for. It does not give
 * you the number of attachments that are children of a post. You can get that
 * by counting the number of children that post has.
 *
 * @since 2.5.0
 *
 * @param string|array $mime_type Optional. Array or comma-separated list of MIME patterns.
 * @return array Number of posts for each mime type.
 */
function wp_count_attachments( $mime_type = '' ) {
	global $wpdb;

	$and = wp_post_mime_type_where( $mime_type );
	$count = $wpdb->get_results( "SELECT post_mime_type, COUNT( * ) AS num_posts FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status != 'trash' $and GROUP BY post_mime_type", ARRAY_A );

	$stats = array( );
	foreach( (array) $count as $row ) {
		$stats[$row['post_mime_type']] = $row['num_posts'];
	}
	$stats['trash'] = $wpdb->get_var( "SELECT COUNT( * ) FROM $wpdb->posts WHERE post_type = 'attachment' AND post_status = 'trash' $and");

	return (object) $stats;
}

/**
 * Check a MIME-Type against a list.
 *
 * If the wildcard_mime_types parameter is a string, it must be comma separated
 * list. If the real_mime_types is a string, it is also comma separated to
 * create the list.
 *
 * @since 2.5.0
 *
 * @param string|array $wildcard_mime_types e.g. audio/mpeg or image (same as image/*) or
 *  flash (same as *flash*).
 * @param string|array $real_mime_types post_mime_type values
 * @return array array(wildcard=>array(real types))
 */
function wp_match_mime_types($wildcard_mime_types, $real_mime_types) {
	$matches = array();
	if ( is_string($wildcard_mime_types) )
		$wildcard_mime_types = array_map('trim', explode(',', $wildcard_mime_types));
	if ( is_string($real_mime_types) )
		$real_mime_types = array_map('trim', explode(',', $real_mime_types));
	$wild = '[-._a-z0-9]*';
	foreach ( (array) $wildcard_mime_types as $type ) {
		$type = str_replace('*', $wild, $type);
		$patternses[1][$type] = "^$type$";
		if ( false === strpos($type, '/') ) {
			$patternses[2][$type] = "^$type/";
			$patternses[3][$type] = $type;
		}
	}
	asort($patternses);
	foreach ( $patternses as $patterns )
		foreach ( $patterns as $type => $pattern )
			foreach ( (array) $real_mime_types as $real )
				if ( preg_match("#$pattern#", $real) && ( empty($matches[$type]) || false === array_search($real, $matches[$type]) ) )
					$matches[$type][] = $real;
	return $matches;
}

/**
 * Convert MIME types into SQL.
 *
 * @since 2.5.0
 *
 * @param string|array $post_mime_types List of mime types or comma separated string of mime types.
 * @param string $table_alias Optional. Specify a table alias, if needed.
 * @return string The SQL AND clause for mime searching.
 */
function wp_post_mime_type_where($post_mime_types, $table_alias = '') {
	$where = '';
	$wildcards = array('', '%', '%/%');
	if ( is_string($post_mime_types) )
		$post_mime_types = array_map('trim', explode(',', $post_mime_types));
	foreach ( (array) $post_mime_types as $mime_type ) {
		$mime_type = preg_replace('/\s/', '', $mime_type);
		$slashpos = strpos($mime_type, '/');
		if ( false !== $slashpos ) {
			$mime_group = preg_replace('/[^-*.a-zA-Z0-9]/', '', substr($mime_type, 0, $slashpos));
			$mime_subgroup = preg_replace('/[^-*.+a-zA-Z0-9]/', '', substr($mime_type, $slashpos + 1));
			if ( empty($mime_subgroup) )
				$mime_subgroup = '*';
			else
				$mime_subgroup = str_replace('/', '', $mime_subgroup);
			$mime_pattern = "$mime_group/$mime_subgroup";
		} else {
			$mime_pattern = preg_replace('/[^-*.a-zA-Z0-9]/', '', $mime_type);
			if ( false === strpos($mime_pattern, '*') )
				$mime_pattern .= '/*';
		}

		$mime_pattern = preg_replace('/\*+/', '%', $mime_pattern);

		if ( in_array( $mime_type, $wildcards ) )
			return '';

		if ( false !== strpos($mime_pattern, '%') )
			$wheres[] = empty($table_alias) ? "post_mime_type LIKE '$mime_pattern'" : "$table_alias.post_mime_type LIKE '$mime_pattern'";
		else
			$wheres[] = empty($table_alias) ? "post_mime_type = '$mime_pattern'" : "$table_alias.post_mime_type = '$mime_pattern'";
	}
	if ( !empty($wheres) )
		$where = ' AND (' . join(' OR ', $wheres) . ') ';
	return $where;
}

/**
 * Trashes or deletes a post or page.
 *
 * When the post and page is permanently deleted, everything that is tied to it is deleted also.
 * This includes comments, post meta fields, and terms associated with the post.
 *
 * The post or page is moved to trash instead of permanently deleted unless trash is
 * disabled, item is already in the trash, or $force_delete is true.
 *
 * @since 1.0.0
 * @uses do_action() on 'delete_post' before deletion unless post type is 'attachment'.
 * @uses do_action() on 'deleted_post' after deletion unless post type is 'attachment'.
 * @uses wp_delete_attachment() if post type is 'attachment'.
 * @uses wp_trash_post() if item should be trashed.
 *
 * @param int $postid Post ID.
 * @param bool $force_delete Whether to bypass trash and force deletion. Defaults to false.
 * @return mixed False on failure
 */
function wp_delete_post( $postid = 0, $force_delete = false ) {
	global $wpdb;

	if ( !$post = $wpdb->get_row($wpdb->prepare("SELECT * FROM $wpdb->posts WHERE ID = %d", $postid)) )
		return $post;

	if ( !$force_delete && ( $post->post_type == 'post' || $post->post_type == 'page') && get_post_status( $postid ) != 'trash' && EMPTY_TRASH_DAYS )
			return wp_trash_post($postid);

	if ( $post->post_type == 'attachment' )
		return wp_delete_attachment( $postid, $force_delete );

	do_action('before_delete_post', $postid);

	delete_post_meta($postid,'_wp_trash_meta_status');
	delete_post_meta($postid,'_wp_trash_meta_time');

	wp_delete_object_term_relationships($postid, get_object_taxonomies($post->post_type));

	$parent_data = array( 'post_parent' => $post->post_parent );
	$parent_where = array( 'post_parent' => $postid );

	if ( is_post_type_hierarchical( $post->post_type ) ) {
		// Point children of this page to its parent, also clean the cache of affected children
		$children_query = $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE post_parent = %d AND post_type = %s", $postid, $post->post_type );
		$children = $wpdb->get_results( $children_query );

		$wpdb->update( $wpdb->posts, $parent_data, $parent_where + array( 'post_type' => $post->post_type ) );
	}

	if ( 'page' == $post->post_type) {
	 	// if the page is defined in option page_on_front or post_for_posts,
		// adjust the corresponding options
		if ( get_option('page_on_front') == $postid ) {
			update_option('show_on_front', 'posts');
			delete_option('page_on_front');
		}
		if ( get_option('page_for_posts') == $postid ) {
			delete_option('page_for_posts');
		}
	} else {
		unstick_post($postid);
	}

	// Do raw query. wp_get_post_revisions() is filtered
	$revision_ids = $wpdb->get_col( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE post_parent = %d AND post_type = 'revision'", $postid ) );
	// Use wp_delete_post (via wp_delete_post_revision) again. Ensures any meta/misplaced data gets cleaned up.
	foreach ( $revision_ids as $revision_id )
		wp_delete_post_revision( $revision_id );

	// Point all attachments to this post up one level
	$wpdb->update( $wpdb->posts, $parent_data, $parent_where + array( 'post_type' => 'attachment' ) );

	$comment_ids = $wpdb->get_col( $wpdb->prepare( "SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = %d", $postid ));
	foreach ( $comment_ids as $comment_id )
		wp_delete_comment( $comment_id, true );

	$post_meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d ", $postid ));
	foreach ( $post_meta_ids as $mid )
		delete_metadata_by_mid( 'post', $mid );

	do_action( 'delete_post', $postid );
	$wpdb->delete( $wpdb->posts, array( 'ID' => $postid ) );
	do_action( 'deleted_post', $postid );

	clean_post_cache( $post );

	if ( is_post_type_hierarchical( $post->post_type ) ) {
		foreach ( (array) $children as $child )
			clean_post_cache( $child );
	}

	wp_clear_scheduled_hook('publish_future_post', array( $postid ) );

	do_action('after_delete_post', $postid);

	return $post;
}

/**
 * Moves a post or page to the Trash
 *
 * If trash is disabled, the post or page is permanently deleted.
 *
 * @since 2.9.0
 * @uses do_action() on 'trash_post' before trashing
 * @uses do_action() on 'trashed_post' after trashing
 * @uses wp_delete_post() if trash is disabled
 *
 * @param int $post_id Post ID.
 * @return mixed False on failure
 */
function wp_trash_post($post_id = 0) {
	if ( !EMPTY_TRASH_DAYS )
		return wp_delete_post($post_id, true);

	if ( !$post = wp_get_single_post($post_id, ARRAY_A) )
		return $post;

	if ( $post['post_status'] == 'trash' )
		return false;

	do_action('wp_trash_post', $post_id);

	add_post_meta($post_id,'_wp_trash_meta_status', $post['post_status']);
	add_post_meta($post_id,'_wp_trash_meta_time', time());

	$post['post_status'] = 'trash';
	wp_insert_post($post);

	wp_trash_post_comments($post_id);

	do_action('trashed_post', $post_id);

	return $post;
}

/**
 * Restores a post or page from the Trash
 *
 * @since 2.9.0
 * @uses do_action() on 'untrash_post' before undeletion
 * @uses do_action() on 'untrashed_post' after undeletion
 *
 * @param int $post_id Post ID.
 * @return mixed False on failure
 */
function wp_untrash_post($post_id = 0) {
	if ( !$post = wp_get_single_post($post_id, ARRAY_A) )
		return $post;

	if ( $post['post_status'] != 'trash' )
		return false;

	do_action('untrash_post', $post_id);

	$post_status = get_post_meta($post_id, '_wp_trash_meta_status', true);

	$post['post_status'] = $post_status;

	delete_post_meta($post_id, '_wp_trash_meta_status');
	delete_post_meta($post_id, '_wp_trash_meta_time');

	wp_insert_post($post);

	wp_untrash_post_comments($post_id);

	do_action('untrashed_post', $post_id);

	return $post;
}

/**
 * Moves comments for a post to the trash
 *
 * @since 2.9.0
 * @uses do_action() on 'trash_post_comments' before trashing
 * @uses do_action() on 'trashed_post_comments' after trashing
 *
 * @param int $post Post ID or object.
 * @return mixed False on failure
 */
function wp_trash_post_comments($post = null) {
	global $wpdb;

	$post = get_post($post);
	if ( empty($post) )
		return;

	$post_id = $post->ID;

	do_action('trash_post_comments', $post_id);

	$comments = $wpdb->get_results( $wpdb->prepare("SELECT comment_ID, comment_approved FROM $wpdb->comments WHERE comment_post_ID = %d", $post_id) );
	if ( empty($comments) )
		return;

	// Cache current status for each comment
	$statuses = array();
	foreach ( $comments as $comment )
		$statuses[$comment->comment_ID] = $comment->comment_approved;
	add_post_meta($post_id, '_wp_trash_meta_comments_status', $statuses);

	// Set status for all comments to post-trashed
	$result = $wpdb->update($wpdb->comments, array('comment_approved' => 'post-trashed'), array('comment_post_ID' => $post_id));

	clean_comment_cache( array_keys($statuses) );

	do_action('trashed_post_comments', $post_id, $statuses);

	return $result;
}

/**
 * Restore comments for a post from the trash
 *
 * @since 2.9.0
 * @uses do_action() on 'untrash_post_comments' before trashing
 * @uses do_action() on 'untrashed_post_comments' after trashing
 *
 * @param int $post Post ID or object.
 * @return mixed False on failure
 */
function wp_untrash_post_comments($post = null) {
	global $wpdb;

	$post = get_post($post);
	if ( empty($post) )
		return;

	$post_id = $post->ID;

	$statuses = get_post_meta($post_id, '_wp_trash_meta_comments_status', true);

	if ( empty($statuses) )
		return true;

	do_action('untrash_post_comments', $post_id);

	// Restore each comment to its original status
	$group_by_status = array();
	foreach ( $statuses as $comment_id => $comment_status )
		$group_by_status[$comment_status][] = $comment_id;

	foreach ( $group_by_status as $status => $comments ) {
		// Sanity check. This shouldn't happen.
		if ( 'post-trashed' == $status )
			$status = '0';
		$comments_in = implode( "', '", $comments );
		$wpdb->query( "UPDATE $wpdb->comments SET comment_approved = '$status' WHERE comment_ID IN ('" . $comments_in . "')" );
	}

	clean_comment_cache( array_keys($statuses) );

	delete_post_meta($post_id, '_wp_trash_meta_comments_status');

	do_action('untrashed_post_comments', $post_id);
}

/**
 * Retrieve the list of categories for a post.
 *
 * Compatibility layer for themes and plugins. Also an easy layer of abstraction
 * away from the complexity of the taxonomy layer.
 *
 * @since 2.1.0
 *
 * @uses wp_get_object_terms() Retrieves the categories. Args details can be found here.
 *
 * @param int $post_id Optional. The Post ID.
 * @param array $args Optional. Overwrite the defaults.
 * @return array
 */
function wp_get_post_categories( $post_id = 0, $args = array() ) {
	$post_id = (int) $post_id;

	$defaults = array('fields' => 'ids');
	$args = wp_parse_args( $args, $defaults );

	$cats = wp_get_object_terms($post_id, 'category', $args);
	return $cats;
}

/**
 * Retrieve the tags for a post.
 *
 * There is only one default for this function, called 'fields' and by default
 * is set to 'all'. There are other defaults that can be overridden in
 * {@link wp_get_object_terms()}.
 *
 * @package WordPress
 * @subpackage Post
 * @since 2.3.0
 *
 * @uses wp_get_object_terms() Gets the tags for returning. Args can be found here
 *
 * @param int $post_id Optional. The Post ID
 * @param array $args Optional. Overwrite the defaults
 * @return array List of post tags.
 */
function wp_get_post_tags( $post_id = 0, $args = array() ) {
	return wp_get_post_terms( $post_id, 'post_tag', $args);
}

/**
 * Retrieve the terms for a post.
 *
 * There is only one default for this function, called 'fields' and by default
 * is set to 'all'. There are other defaults that can be overridden in
 * {@link wp_get_object_terms()}.
 *
 * @package WordPress
 * @subpackage Post
 * @since 2.8.0
 *
 * @uses wp_get_object_terms() Gets the tags for returning. Args can be found here
 *
 * @param int $post_id Optional. The Post ID
 * @param string $taxonomy The taxonomy for which to retrieve terms. Defaults to post_tag.
 * @param array $args Optional. Overwrite the defaults
 * @return array List of post tags.
 */
function wp_get_post_terms( $post_id = 0, $taxonomy = 'post_tag', $args = array() ) {
	$post_id = (int) $post_id;

	$defaults = array('fields' => 'all');
	$args = wp_parse_args( $args, $defaults );

	$tags = wp_get_object_terms($post_id, $taxonomy, $args);

	return $tags;
}

/**
 * Retrieve number of recent posts.
 *
 * @since 1.0.0
 * @uses wp_parse_args()
 * @uses get_posts()
 *
 * @param string $deprecated Deprecated.
 * @param array $args Optional. Overrides defaults.
 * @param string $output Optional.
 * @return unknown.
 */
function wp_get_recent_posts( $args = array(), $output = ARRAY_A ) {

	if ( is_numeric( $args ) ) {
		_deprecated_argument( __FUNCTION__, '3.1', __( 'Passing an integer number of posts is deprecated. Pass an array of arguments instead.' ) );
		$args = array( 'numberposts' => absint( $args ) );
	}

	// Set default arguments
	$defaults = array(
		'numberposts' => 10, 'offset' => 0,
		'category' => 0, 'orderby' => 'post_date',
		'order' => 'DESC', 'include' => '',
		'exclude' => '', 'meta_key' => '',
		'meta_value' =>'', 'post_type' => 'post', 'post_status' => 'draft, publish, future, pending, private',
		'suppress_filters' => true
	);

	$r = wp_parse_args( $args, $defaults );

	$results = get_posts( $r );

	// Backward compatibility. Prior to 3.1 expected posts to be returned in array
	if ( ARRAY_A == $output ){
		foreach( $results as $key => $result ) {
			$results[$key] = get_object_vars( $result );
		}
		return $results ? $results : array();
	}

	return $results ? $results : false;

}

/**
 * Retrieve a single post, based on post ID.
 *
 * Has categories in 'post_category' property or key. Has tags in 'tags_input'
 * property or key.
 *
 * @since 1.0.0
 *
 * @param int $postid Post ID.
 * @param string $mode How to return result, either OBJECT, ARRAY_N, or ARRAY_A.
 * @return object|array Post object or array holding post contents and information
 */
function wp_get_single_post($postid = 0, $mode = OBJECT) {
	$postid = (int) $postid;

	$post = get_post($postid, $mode);

	if (
		( OBJECT == $mode && empty( $post->ID ) ) ||
		( OBJECT != $mode && empty( $post['ID'] ) )
	)
		return ( OBJECT == $mode ? null : array() );

	// Set categories and tags
	if ( $mode == OBJECT ) {
		$post->post_category = array();
		if ( is_object_in_taxonomy($post->post_type, 'category') )
			$post->post_category = wp_get_post_categories($postid);
		$post->tags_input = array();
		if ( is_object_in_taxonomy($post->post_type, 'post_tag') )
			$post->tags_input = wp_get_post_tags($postid, array('fields' => 'names'));
	} else {
		$post['post_category'] = array();
		if ( is_object_in_taxonomy($post['post_type'], 'category') )
			$post['post_category'] = wp_get_post_categories($postid);
		$post['tags_input'] = array();
		if ( is_object_in_taxonomy($post['post_type'], 'post_tag') )
			$post['tags_input'] = wp_get_post_tags($postid, array('fields' => 'names'));
	}

	return $post;
}

/**
 * Insert a post.
 *
 * If the $postarr parameter has 'ID' set to a value, then post will be updated.
 *
 * You can set the post date manually, but setting the values for 'post_date'
 * and 'post_date_gmt' keys. You can close the comments or open the comments by
 * setting the value for 'comment_status' key.
 *
 * The defaults for the parameter $postarr are:
 *     'post_status'   - Default is 'draft'.
 *     'post_type'     - Default is 'post'.
 *     'post_author'   - Default is current user ID ($user_ID). The ID of the user who added the post.
 *     'ping_status'   - Default is the value in 'default_ping_status' option.
 *                       Whether the attachment can accept pings.
 *     'post_parent'   - Default is 0. Set this for the post it belongs to, if any.
 *     'menu_order'    - Default is 0. The order it is displayed.
 *     'to_ping'       - Whether to ping.
 *     'pinged'        - Default is empty string.
 *     'post_password' - Default is empty string. The password to access the attachment.
 *     'guid'          - Global Unique ID for referencing the attachment.
 *     'post_content_filtered' - Post content filtered.
 *     'post_excerpt'  - Post excerpt.
 *
 * @since 1.0.0
 * @uses $wpdb
 * @uses $user_ID
 * @uses do_action() Calls 'pre_post_update' on post ID if this is an update.
 * @uses do_action() Calls 'edit_post' action on post ID and post data if this is an update.
 * @uses do_action() Calls 'save_post' and 'wp_insert_post' on post id and post data just before returning.
 * @uses apply_filters() Calls 'wp_insert_post_data' passing $data, $postarr prior to database update or insert.
 * @uses wp_transition_post_status()
 *
 * @param array $postarr Elements that make up post to insert.
 * @param bool $wp_error Optional. Allow return of WP_Error on failure.
 * @return int|WP_Error The value 0 or WP_Error on failure. The post ID on success.
 */
function wp_insert_post($postarr, $wp_error = false) {
	global $wpdb, $user_ID;

	$defaults = array('post_status' => 'draft', 'post_type' => 'post', 'post_author' => $user_ID,
		'ping_status' => get_option('default_ping_status'), 'post_parent' => 0,
		'menu_order' => 0, 'to_ping' =>  '', 'pinged' => '', 'post_password' => '',
		'guid' => '', 'post_content_filtered' => '', 'post_excerpt' => '', 'import_id' => 0,
		'post_content' => '', 'post_title' => '');

	$postarr = wp_parse_args($postarr, $defaults);

	unset( $postarr[ 'filter' ] );

	$postarr = sanitize_post($postarr, 'db');

	// export array as variables
	extract($postarr, EXTR_SKIP);

	// Are we updating or creating?
	$update = false;
	if ( !empty($ID) ) {
		$update = true;
		$previous_status = get_post_field('post_status', $ID);
	} else {
		$previous_status = 'new';
	}

	$maybe_empty = ! $post_content && ! $post_title && ! $post_excerpt && post_type_supports( $post_type, 'editor' )
		&& post_type_supports( $post_type, 'title' ) && post_type_supports( $post_type, 'excerpt' );
	if ( apply_filters( 'wp_insert_post_empty_content', $maybe_empty, $postarr ) ) {
		if ( $wp_error )
			return new WP_Error( 'empty_content', __( 'Content, title, and excerpt are empty.' ) );
		else
			return 0;
	}

	if ( empty($post_type) )
		$post_type = 'post';

	if ( empty($post_status) )
		$post_status = 'draft';

	if ( !empty($post_category) )
		$post_category = array_filter($post_category); // Filter out empty terms

	// Make sure we set a valid category.
	if ( empty($post_category) || 0 == count($post_category) || !is_array($post_category) ) {
		// 'post' requires at least one category.
		if ( 'post' == $post_type && 'auto-draft' != $post_status )
			$post_category = array( get_option('default_category') );
		else
			$post_category = array();
	}

	if ( empty($post_author) )
		$post_author = $user_ID;

	$post_ID = 0;

	// Get the post ID and GUID
	if ( $update ) {
		$post_ID = (int) $ID;
		$guid = get_post_field( 'guid', $post_ID );
		$post_before = get_post($post_ID);
	}

	// Don't allow contributors to set the post slug for pending review posts
	if ( 'pending' == $post_status && !current_user_can( 'publish_posts' ) )
		$post_name = '';

	// Create a valid post name. Drafts and pending posts are allowed to have an empty
	// post name.
	if ( empty($post_name) ) {
		if ( !in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )
			$post_name = sanitize_title($post_title);
		else
			$post_name = '';
	} else {
		// On updates, we need to check to see if it's using the old, fixed sanitization context.
		$check_name = sanitize_title( $post_name, '', 'old-save' );
		if ( $update && strtolower( urlencode( $post_name ) ) == $check_name && get_post_field( 'post_name', $ID ) == $check_name )
			$post_name = $check_name;
		else // new post, or slug has changed.
			$post_name = sanitize_title($post_name);
	}

	// If the post date is empty (due to having been new or a draft) and status is not 'draft' or 'pending', set date to now
	if ( empty($post_date) || '0000-00-00 00:00:00' == $post_date )
		$post_date = current_time('mysql');

	if ( empty($post_date_gmt) || '0000-00-00 00:00:00' == $post_date_gmt ) {
		if ( !in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )
			$post_date_gmt = get_gmt_from_date($post_date);
		else
			$post_date_gmt = '0000-00-00 00:00:00';
	}

	if ( $update || '0000-00-00 00:00:00' == $post_date ) {
		$post_modified     = current_time( 'mysql' );
		$post_modified_gmt = current_time( 'mysql', 1 );
	} else {
		$post_modified     = $post_date;
		$post_modified_gmt = $post_date_gmt;
	}

	if ( 'publish' == $post_status ) {
		$now = gmdate('Y-m-d H:i:59');
		if ( mysql2date('U', $post_date_gmt, false) > mysql2date('U', $now, false) )
			$post_status = 'future';
	} elseif( 'future' == $post_status ) {
		$now = gmdate('Y-m-d H:i:59');
		if ( mysql2date('U', $post_date_gmt, false) <= mysql2date('U', $now, false) )
			$post_status = 'publish';
	}

	if ( empty($comment_status) ) {
		if ( $update )
			$comment_status = 'closed';
		else
			$comment_status = get_option('default_comment_status');
	}
	if ( empty($ping_status) )
		$ping_status = get_option('default_ping_status');

	if ( isset($to_ping) )
		$to_ping = sanitize_trackback_urls( $to_ping );
	else
		$to_ping = '';

	if ( ! isset($pinged) )
		$pinged = '';

	if ( isset($post_parent) )
		$post_parent = (int) $post_parent;
	else
		$post_parent = 0;

	// Check the post_parent to see if it will cause a hierarchy loop
	$post_parent = apply_filters( 'wp_insert_post_parent', $post_parent, $post_ID, compact( array_keys( $postarr ) ), $postarr );

	if ( isset($menu_order) )
		$menu_order = (int) $menu_order;
	else
		$menu_order = 0;

	if ( !isset($post_password) || 'private' == $post_status )
		$post_password = '';

	$post_name = wp_unique_post_slug($post_name, $post_ID, $post_status, $post_type, $post_parent);

	// expected_slashed (everything!)
	$data = compact( array( 'post_author', 'post_date', 'post_date_gmt', 'post_content', 'post_content_filtered', 'post_title', 'post_excerpt', 'post_status', 'post_type', 'comment_status', 'ping_status', 'post_password', 'post_name', 'to_ping', 'pinged', 'post_modified', 'post_modified_gmt', 'post_parent', 'menu_order', 'guid' ) );
	$data = apply_filters('wp_insert_post_data', $data, $postarr);
	$data = stripslashes_deep( $data );
	$where = array( 'ID' => $post_ID );

	if ( $update ) {
		do_action( 'pre_post_update', $post_ID );
		if ( false === $wpdb->update( $wpdb->posts, $data, $where ) ) {
			if ( $wp_error )
				return new WP_Error('db_update_error', __('Could not update post in the database'), $wpdb->last_error);
			else
				return 0;
		}
	} else {
		if ( isset($post_mime_type) )
			$data['post_mime_type'] = stripslashes( $post_mime_type ); // This isn't in the update
		// If there is a suggested ID, use it if not already present
		if ( !empty($import_id) ) {
			$import_id = (int) $import_id;
			if ( ! $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE ID = %d", $import_id) ) ) {
				$data['ID'] = $import_id;
			}
		}
		if ( false === $wpdb->insert( $wpdb->posts, $data ) ) {
			if ( $wp_error )
				return new WP_Error('db_insert_error', __('Could not insert post into the database'), $wpdb->last_error);
			else
				return 0;
		}
		$post_ID = (int) $wpdb->insert_id;

		// use the newly generated $post_ID
		$where = array( 'ID' => $post_ID );
	}

	if ( empty($data['post_name']) && !in_array( $data['post_status'], array( 'draft', 'pending', 'auto-draft' ) ) ) {
		$data['post_name'] = sanitize_title($data['post_title'], $post_ID);
		$wpdb->update( $wpdb->posts, array( 'post_name' => $data['post_name'] ), $where );
	}

	if ( is_object_in_taxonomy($post_type, 'category') )
		wp_set_post_categories( $post_ID, $post_category );

	if ( isset( $tags_input ) && is_object_in_taxonomy($post_type, 'post_tag') )
		wp_set_post_tags( $post_ID, $tags_input );

	// new-style support for all custom taxonomies
	if ( !empty($tax_input) ) {
		foreach ( $tax_input as $taxonomy => $tags ) {
			$taxonomy_obj = get_taxonomy($taxonomy);
			if ( is_array($tags) ) // array = hierarchical, string = non-hierarchical.
				$tags = array_filter($tags);
			if ( current_user_can($taxonomy_obj->cap->assign_terms) )
				wp_set_post_terms( $post_ID, $tags, $taxonomy );
		}
	}

	$current_guid = get_post_field( 'guid', $post_ID );

	clean_post_cache( $post_ID );

	// Set GUID
	if ( !$update && '' == $current_guid )
		$wpdb->update( $wpdb->posts, array( 'guid' => get_permalink( $post_ID ) ), $where );

	$post = get_post($post_ID);

	if ( !empty($page_template) && 'page' == $data['post_type'] ) {
		$post->page_template = $page_template;
		$page_templates = get_page_templates();
		if ( 'default' != $page_template && !in_array($page_template, $page_templates) ) {
			if ( $wp_error )
				return new WP_Error('invalid_page_template', __('The page template is invalid.'));
			else
				return 0;
		}
		update_post_meta($post_ID, '_wp_page_template',  $page_template);
	}

	wp_transition_post_status($data['post_status'], $previous_status, $post);

	if ( $update ) {
		do_action('edit_post', $post_ID, $post);
		$post_after = get_post($post_ID);
		do_action( 'post_updated', $post_ID, $post_after, $post_before);
	}

	do_action('save_post', $post_ID, $post);
	do_action('wp_insert_post', $post_ID, $post);

	return $post_ID;
}

/**
 * Update a post with new post data.
 *
 * The date does not have to be set for drafts. You can set the date and it will
 * not be overridden.
 *
 * @since 1.0.0
 *
 * @param array|object $postarr Post data. Arrays are expected to be escaped, objects are not.
 * @return int 0 on failure, Post ID on success.
 */
function wp_update_post($postarr = array()) {
	if ( is_object($postarr) ) {
		// non-escaped post was passed
		$postarr = get_object_vars($postarr);
		$postarr = add_magic_quotes($postarr);
	}

	// First, get all of the original fields
	$post = wp_get_single_post($postarr['ID'], ARRAY_A);

	// Escape data pulled from DB.
	$post = add_magic_quotes($post);

	// Passed post category list overwrites existing category list if not empty.
	if ( isset($postarr['post_category']) && is_array($postarr['post_category'])
			 && 0 != count($postarr['post_category']) )
		$post_cats = $postarr['post_category'];
	else
		$post_cats = $post['post_category'];

	// Drafts shouldn't be assigned a date unless explicitly done so by the user
	if ( isset( $post['post_status'] ) && in_array($post['post_status'], array('draft', 'pending', 'auto-draft')) && empty($postarr['edit_date']) &&
			 ('0000-00-00 00:00:00' == $post['post_date_gmt']) )
		$clear_date = true;
	else
		$clear_date = false;

	// Merge old and new fields with new fields overwriting old ones.
	$postarr = array_merge($post, $postarr);
	$postarr['post_category'] = $post_cats;
	if ( $clear_date ) {
		$postarr['post_date'] = current_time('mysql');
		$postarr['post_date_gmt'] = '';
	}

	if ($postarr['post_type'] == 'attachment')
		return wp_insert_attachment($postarr);

	return wp_insert_post($postarr);
}

/**
 * Publish a post by transitioning the post status.
 *
 * @since 2.1.0
 * @uses $wpdb
 * @uses do_action() Calls 'edit_post', 'save_post', and 'wp_insert_post' on post_id and post data.
 *
 * @param int $post_id Post ID.
 * @return null
 */
function wp_publish_post($post_id) {
	global $wpdb;

	$post = get_post($post_id);

	if ( empty($post) )
		return;

	if ( 'publish' == $post->post_status )
		return;

	$wpdb->update( $wpdb->posts, array( 'post_status' => 'publish' ), array( 'ID' => $post_id ) );

	$old_status = $post->post_status;
	$post->post_status = 'publish';
	wp_transition_post_status('publish', $old_status, $post);

	do_action('edit_post', $post_id, $post);
	do_action('save_post', $post_id, $post);
	do_action('wp_insert_post', $post_id, $post);
}

/**
 * Publish future post and make sure post ID has future post status.
 *
 * Invoked by cron 'publish_future_post' event. This safeguard prevents cron
 * from publishing drafts, etc.
 *
 * @since 2.5.0
 *
 * @param int $post_id Post ID.
 * @return null Nothing is returned. Which can mean that no action is required or post was published.
 */
function check_and_publish_future_post($post_id) {

	$post = get_post($post_id);

	if ( empty($post) )
		return;

	if ( 'future' != $post->post_status )
		return;

	$time = strtotime( $post->post_date_gmt . ' GMT' );

	if ( $time > time() ) { // Uh oh, someone jumped the gun!
		wp_clear_scheduled_hook( 'publish_future_post', array( $post_id ) ); // clear anything else in the system
		wp_schedule_single_event( $time, 'publish_future_post', array( $post_id ) );
		return;
	}

	return wp_publish_post($post_id);
}

/**
 * Computes a unique slug for the post, when given the desired slug and some post details.
 *
 * @since 2.8.0
 *
 * @global wpdb $wpdb
 * @global WP_Rewrite $wp_rewrite
 * @param string $slug the desired slug (post_name)
 * @param integer $post_ID
 * @param string $post_status no uniqueness checks are made if the post is still draft or pending
 * @param string $post_type
 * @param integer $post_parent
 * @return string unique slug for the post, based on $post_name (with a -1, -2, etc. suffix)
 */
function wp_unique_post_slug( $slug, $post_ID, $post_status, $post_type, $post_parent ) {
	if ( in_array( $post_status, array( 'draft', 'pending', 'auto-draft' ) ) )
		return $slug;

	global $wpdb, $wp_rewrite;

	$feeds = $wp_rewrite->feeds;
	if ( ! is_array( $feeds ) )
		$feeds = array();

	$hierarchical_post_types = get_post_types( array('hierarchical' => true) );
	if ( 'attachment' == $post_type ) {
		// Attachment slugs must be unique across all types.
		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND ID != %d LIMIT 1";
		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_ID ) );

		if ( $post_name_check || in_array( $slug, $feeds ) || apply_filters( 'wp_unique_post_slug_is_bad_attachment_slug', false, $slug ) ) {
			$suffix = 2;
			do {
				$alt_post_name = substr ($slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";
				$post_name_check = $wpdb->get_var( $wpdb->prepare($check_sql, $alt_post_name, $post_ID ) );
				$suffix++;
			} while ( $post_name_check );
			$slug = $alt_post_name;
		}
	} elseif ( in_array( $post_type, $hierarchical_post_types ) ) {
		// Page slugs must be unique within their own trees. Pages are in a separate
		// namespace than posts so page slugs are allowed to overlap post slugs.
		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type IN ( '" . implode( "', '", esc_sql( $hierarchical_post_types ) ) . "' ) AND ID != %d AND post_parent = %d LIMIT 1";
		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_ID, $post_parent ) );

		if ( $post_name_check || in_array( $slug, $feeds ) || preg_match( "@^($wp_rewrite->pagination_base)?\d+$@", $slug )  || apply_filters( 'wp_unique_post_slug_is_bad_hierarchical_slug', false, $slug, $post_type, $post_parent ) ) {
			$suffix = 2;
			do {
				$alt_post_name = substr( $slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";
				$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $alt_post_name, $post_ID, $post_parent ) );
				$suffix++;
			} while ( $post_name_check );
			$slug = $alt_post_name;
		}
	} else {
		// Post slugs must be unique across all posts.
		$check_sql = "SELECT post_name FROM $wpdb->posts WHERE post_name = %s AND post_type = %s AND ID != %d LIMIT 1";
		$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $slug, $post_type, $post_ID ) );

		if ( $post_name_check || in_array( $slug, $feeds ) || apply_filters( 'wp_unique_post_slug_is_bad_flat_slug', false, $slug, $post_type ) ) {
			$suffix = 2;
			do {
				$alt_post_name = substr( $slug, 0, 200 - ( strlen( $suffix ) + 1 ) ) . "-$suffix";
				$post_name_check = $wpdb->get_var( $wpdb->prepare( $check_sql, $alt_post_name, $post_type, $post_ID ) );
				$suffix++;
			} while ( $post_name_check );
			$slug = $alt_post_name;
		}
	}

	return apply_filters( 'wp_unique_post_slug', $slug, $post_ID, $post_status, $post_type, $post_parent );
}

/**
 * Adds tags to a post.
 *
 * @uses wp_set_post_tags() Same first two parameters, but the last parameter is always set to true.
 *
 * @package WordPress
 * @subpackage Post
 * @since 2.3.0
 *
 * @param int $post_id Post ID
 * @param string $tags The tags to set for the post, separated by commas.
 * @return bool|null Will return false if $post_id is not an integer or is 0. Will return null otherwise
 */
function wp_add_post_tags($post_id = 0, $tags = '') {
	return wp_set_post_tags($post_id, $tags, true);
}

/**
 * Set the tags for a post.
 *
 * @since 2.3.0
 * @uses wp_set_object_terms() Sets the tags for the post.
 *
 * @param int $post_id Post ID.
 * @param string $tags The tags to set for the post, separated by commas.
 * @param bool $append If true, don't delete existing tags, just add on. If false, replace the tags with the new tags.
 * @return mixed Array of affected term IDs. WP_Error or false on failure.
 */
function wp_set_post_tags( $post_id = 0, $tags = '', $append = false ) {
	return wp_set_post_terms( $post_id, $tags, 'post_tag', $append);
}

/**
 * Set the terms for a post.
 *
 * @since 2.8.0
 * @uses wp_set_object_terms() Sets the tags for the post.
 *
 * @param int $post_id Post ID.
 * @param string $tags The tags to set for the post, separated by commas.
 * @param string $taxonomy Taxonomy name. Defaults to 'post_tag'.
 * @param bool $append If true, don't delete existing tags, just add on. If false, replace the tags with the new tags.
 * @return mixed Array of affected term IDs. WP_Error or false on failure.
 */
function wp_set_post_terms( $post_id = 0, $tags = '', $taxonomy = 'post_tag', $append = false ) {
	$post_id = (int) $post_id;

	if ( !$post_id )
		return false;

	if ( empty($tags) )
		$tags = array();

	if ( ! is_array( $tags ) ) {
		$comma = _x( ',', 'tag delimiter' );
		if ( ',' !== $comma )
			$tags = str_replace( $comma, ',', $tags );
		$tags = explode( ',', trim( $tags, " \n\t\r\0\x0B," ) );
	}

	// Hierarchical taxonomies must always pass IDs rather than names so that children with the same
	// names but different parents aren't confused.
	if ( is_taxonomy_hierarchical( $taxonomy ) ) {
		$tags = array_map( 'intval', $tags );
		$tags = array_unique( $tags );
	}

	return wp_set_object_terms($post_id, $tags, $taxonomy, $append);
}

/**
 * Set categories for a post.
 *
 * If the post categories parameter is not set, then the default category is
 * going used.
 *
 * @since 2.1.0
 *
 * @param int $post_ID Post ID.
 * @param array $post_categories Optional. List of categories.
 * @return bool|mixed
 */
function wp_set_post_categories($post_ID = 0, $post_categories = array()) {
	$post_ID = (int) $post_ID;
	$post_type = get_post_type( $post_ID );
	$post_status = get_post_status( $post_ID );
	// If $post_categories isn't already an array, make it one:
	if ( !is_array($post_categories) || empty($post_categories) ) {
		if ( 'post' == $post_type && 'auto-draft' != $post_status )
			$post_categories = array( get_option('default_category') );
		else
			$post_categories = array();
	} else if ( 1 == count($post_categories) && '' == reset($post_categories) ) {
		return true;
	}

	if ( !empty($post_categories) ) {
		$post_categories = array_map('intval', $post_categories);
		$post_categories = array_unique($post_categories);
	}

	return wp_set_object_terms($post_ID, $post_categories, 'category');
}

/**
 * Transition the post status of a post.
 *
 * Calls hooks to transition post status.
 *
 * The first is 'transition_post_status' with new status, old status, and post data.
 *
 * The next action called is 'OLDSTATUS_to_NEWSTATUS' the 'NEWSTATUS' is the
 * $new_status parameter and the 'OLDSTATUS' is $old_status parameter; it has the
 * post data.
 *
 * The final action is named 'NEWSTATUS_POSTTYPE', 'NEWSTATUS' is from the $new_status
 * parameter and POSTTYPE is post_type post data.
 *
 * @since 2.3.0
 * @link http://codex.wordpress.org/Post_Status_Transitions
 *
 * @uses do_action() Calls 'transition_post_status' on $new_status, $old_status and
 *  $post if there is a status change.
 * @uses do_action() Calls '{$old_status}_to_{$new_status}' on $post if there is a status change.
 * @uses do_action() Calls '{$new_status}_{$post->post_type}' on post ID and $post.
 *
 * @param string $new_status Transition to this post status.
 * @param string $old_status Previous post status.
 * @param object $post Post data.
 */
function wp_transition_post_status($new_status, $old_status, $post) {
	do_action('transition_post_status', $new_status, $old_status, $post);
	do_action("{$old_status}_to_{$new_status}", $post);
	do_action("{$new_status}_{$post->post_type}", $post->ID, $post);
}

//
// Trackback and ping functions
//

/**
 * Add a URL to those already pung.
 *
 * @since 1.5.0
 * @uses $wpdb
 *
 * @param int $post_id Post ID.
 * @param string $uri Ping URI.
 * @return int How many rows were updated.
 */
function add_ping($post_id, $uri) {
	global $wpdb;
	$pung = $wpdb->get_var( $wpdb->prepare( "SELECT pinged FROM $wpdb->posts WHERE ID = %d", $post_id ));
	$pung = trim($pung);
	$pung = preg_split('/\s/', $pung);
	$pung[] = $uri;
	$new = implode("\n", $pung);
	$new = apply_filters('add_ping', $new);
	// expected_slashed ($new)
	$new = stripslashes($new);
	return $wpdb->update( $wpdb->posts, array( 'pinged' => $new ), array( 'ID' => $post_id ) );
}

/**
 * Retrieve enclosures already enclosed for a post.
 *
 * @since 1.5.0
 * @uses $wpdb
 *
 * @param int $post_id Post ID.
 * @return array List of enclosures
 */
function get_enclosed($post_id) {
	$custom_fields = get_post_custom( $post_id );
	$pung = array();
	if ( !is_array( $custom_fields ) )
		return $pung;

	foreach ( $custom_fields as $key => $val ) {
		if ( 'enclosure' != $key || !is_array( $val ) )
			continue;
		foreach( $val as $enc ) {
			$enclosure = explode( "\n", $enc );
			$pung[] = trim( $enclosure[ 0 ] );
		}
	}
	$pung = apply_filters('get_enclosed', $pung, $post_id);
	return $pung;
}

/**
 * Retrieve URLs already pinged for a post.
 *
 * @since 1.5.0
 * @uses $wpdb
 *
 * @param int $post_id Post ID.
 * @return array
 */
function get_pung($post_id) {
	global $wpdb;
	$pung = $wpdb->get_var( $wpdb->prepare( "SELECT pinged FROM $wpdb->posts WHERE ID = %d", $post_id ));
	$pung = trim($pung);
	$pung = preg_split('/\s/', $pung);
	$pung = apply_filters('get_pung', $pung);
	return $pung;
}

/**
 * Retrieve URLs that need to be pinged.
 *
 * @since 1.5.0
 * @uses $wpdb
 *
 * @param int $post_id Post ID
 * @return array
 */
function get_to_ping($post_id) {
	global $wpdb;
	$to_ping = $wpdb->get_var( $wpdb->prepare( "SELECT to_ping FROM $wpdb->posts WHERE ID = %d", $post_id ));
	$to_ping = sanitize_trackback_urls( $to_ping );
	$to_ping = preg_split('/\s/', $to_ping, -1, PREG_SPLIT_NO_EMPTY);
	$to_ping = apply_filters('get_to_ping',  $to_ping);
	return $to_ping;
}

/**
 * Do trackbacks for a list of URLs.
 *
 * @since 1.0.0
 *
 * @param string $tb_list Comma separated list of URLs
 * @param int $post_id Post ID
 */
function trackback_url_list($tb_list, $post_id) {
	if ( ! empty( $tb_list ) ) {
		// get post data
		$postdata = wp_get_single_post($post_id, ARRAY_A);

		// import postdata as variables
		extract($postdata, EXTR_SKIP);

		// form an excerpt
		$excerpt = strip_tags($post_excerpt ? $post_excerpt : $post_content);

		if (strlen($excerpt) > 255) {
			$excerpt = substr($excerpt,0,252) . '...';
		}

		$trackback_urls = explode(',', $tb_list);
		foreach( (array) $trackback_urls as $tb_url) {
			$tb_url = trim($tb_url);
			trackback($tb_url, stripslashes($post_title), $excerpt, $post_id);
		}
	}
}

//
// Page functions
//

/**
 * Get a list of page IDs.
 *
 * @since 2.0.0
 * @uses $wpdb
 *
 * @return array List of page IDs.
 */
function get_all_page_ids() {
	global $wpdb;

	$page_ids = wp_cache_get('all_page_ids', 'posts');
	if ( ! is_array( $page_ids ) ) {
		$page_ids = $wpdb->get_col("SELECT ID FROM $wpdb->posts WHERE post_type = 'page'");
		wp_cache_add('all_page_ids', $page_ids, 'posts');
	}

	return $page_ids;
}

/**
 * Retrieves page data given a page ID or page object.
 *
 * @since 1.5.1
 *
 * @param mixed $page Page object or page ID. Passed by reference.
 * @param string $output What to output. OBJECT, ARRAY_A, or ARRAY_N.
 * @param string $filter How the return value should be filtered.
 * @return mixed Page data.
 */
function &get_page(&$page, $output = OBJECT, $filter = 'raw') {
	$p = get_post($page, $output, $filter);
	return $p;
}

/**
 * Retrieves a page given its path.
 *
 * @since 2.1.0
 * @uses $wpdb
 *
 * @param string $page_path Page path
 * @param string $output Optional. Output type. OBJECT, ARRAY_N, or ARRAY_A. Default OBJECT.
 * @param string $post_type Optional. Post type. Default page.
 * @return mixed Null when complete.
 */
function get_page_by_path($page_path, $output = OBJECT, $post_type = 'page') {
	global $wpdb;

	$page_path = rawurlencode(urldecode($page_path));
	$page_path = str_replace('%2F', '/', $page_path);
	$page_path = str_replace('%20', ' ', $page_path);
	$parts = explode( '/', trim( $page_path, '/' ) );
	$parts = array_map( 'esc_sql', $parts );
	$parts = array_map( 'sanitize_title_for_query', $parts );

	$in_string = "'". implode( "','", $parts ) . "'";
	$post_type_sql = $post_type;
	$wpdb->escape_by_ref( $post_type_sql );
	$pages = $wpdb->get_results( "SELECT ID, post_name, post_parent FROM $wpdb->posts WHERE post_name IN ($in_string) AND (post_type = '$post_type_sql' OR post_type = 'attachment')", OBJECT_K );

	$revparts = array_reverse( $parts );

	$foundid = 0;
	foreach ( (array) $pages as $page ) {
		if ( $page->post_name == $revparts[0] ) {
			$count = 0;
			$p = $page;
			while ( $p->post_parent != 0 && isset( $pages[ $p->post_parent ] ) ) {
				$count++;
				$parent = $pages[ $p->post_parent ];
				if ( ! isset( $revparts[ $count ] ) || $parent->post_name != $revparts[ $count ] )
					break;
				$p = $parent;
			}

			if ( $p->post_parent == 0 && $count+1 == count( $revparts ) && $p->post_name == $revparts[ $count ] ) {
				$foundid = $page->ID;
				break;
			}
		}
	}

	if ( $foundid )
		return get_page( $foundid, $output );

	return null;
}

/**
 * Retrieve a page given its title.
 *
 * @since 2.1.0
 * @uses $wpdb
 *
 * @param string $page_title Page title
 * @param string $output Optional. Output type. OBJECT, ARRAY_N, or ARRAY_A. Default OBJECT.
 * @param string $post_type Optional. Post type. Default page.
 * @return mixed
 */
function get_page_by_title($page_title, $output = OBJECT, $post_type = 'page' ) {
	global $wpdb;
	$page = $wpdb->get_var( $wpdb->prepare( "SELECT ID FROM $wpdb->posts WHERE post_title = %s AND post_type= %s", $page_title, $post_type ) );
	if ( $page )
		return get_page($page, $output);

	return null;
}

/**
 * Retrieve child pages from list of pages matching page ID.
 *
 * Matches against the pages parameter against the page ID. Also matches all
 * children for the same to retrieve all children of a page. Does not make any
 * SQL queries to get the children.
 *
 * @since 1.5.1
 *
 * @param int $page_id Page ID.
 * @param array $pages List of pages' objects.
 * @return array
 */
function &get_page_children($page_id, $pages) {
	$page_list = array();
	foreach ( (array) $pages as $page ) {
		if ( $page->post_parent == $page_id ) {
			$page_list[] = $page;
			if ( $children = get_page_children($page->ID, $pages) )
				$page_list = array_merge($page_list, $children);
		}
	}
	return $page_list;
}

/**
 * Order the pages with children under parents in a flat list.
 *
 * It uses auxiliary structure to hold parent-children relationships and
 * runs in O(N) complexity
 *
 * @since 2.0.0
 *
 * @param array $pages Posts array.
 * @param int $page_id Parent page ID.
 * @return array A list arranged by hierarchy. Children immediately follow their parents.
 */
function &get_page_hierarchy( &$pages, $page_id = 0 ) {
	if ( empty( $pages ) ) {
		$result = array();
		return $result;
	}

	$children = array();
	foreach ( (array) $pages as $p ) {
		$parent_id = intval( $p->post_parent );
		$children[ $parent_id ][] = $p;
	}

	$result = array();
	_page_traverse_name( $page_id, $children, $result );

	return $result;
}

/**
 * function to traverse and return all the nested children post names of a root page.
 * $children contains parent-children relations
 *
 * @since 2.9.0
 */
function _page_traverse_name( $page_id, &$children, &$result ){
	if ( isset( $children[ $page_id ] ) ){
		foreach( (array)$children[ $page_id ] as $child ) {
			$result[ $child->ID ] = $child->post_name;
			_page_traverse_name( $child->ID, $children, $result );
		}
	}
}

/**
 * Builds URI for a page.
 *
 * Sub pages will be in the "directory" under the parent page post name.
 *
 * @since 1.5.0
 *
 * @param mixed $page Page object or page ID.
 * @return string Page URI.
 */
function get_page_uri($page) {
	if ( ! is_object($page) )
		$page = get_page($page);
	$uri = $page->post_name;

	// A page cannot be it's own parent.
	if ( $page->post_parent == $page->ID )
		return $uri;

	while ($page->post_parent != 0) {
		$page = get_page($page->post_parent);
		$uri = $page->post_name . "/" . $uri;
	}

	return $uri;
}

/**
 * Retrieve a list of pages.
 *
 * The defaults that can be overridden are the following: 'child_of',
 * 'sort_order', 'sort_column', 'post_title', 'hierarchical', 'exclude',
 * 'include', 'meta_key', 'meta_value','authors', 'number', and 'offset'.
 *
 * @since 1.5.0
 * @uses $wpdb
 *
 * @param mixed $args Optional. Array or string of options that overrides defaults.
 * @return array List of pages matching defaults or $args
 */
function &get_pages($args = '') {
	global $wpdb;

	$defaults = array(
		'child_of' => 0, 'sort_order' => 'ASC',
		'sort_column' => 'post_title', 'hierarchical' => 1,
		'exclude' => array(), 'include' => array(),
		'meta_key' => '', 'meta_value' => '',
		'authors' => '', 'parent' => -1, 'exclude_tree' => '',
		'number' => '', 'offset' => 0,
		'post_type' => 'page', 'post_status' => 'publish',
	);

	$r = wp_parse_args( $args, $defaults );
	extract( $r, EXTR_SKIP );
	$number = (int) $number;
	$offset = (int) $offset;

	// Make sure the post type is hierarchical
	$hierarchical_post_types = get_post_types( array( 'hierarchical' => true ) );
	if ( !in_array( $post_type, $hierarchical_post_types ) )
		return false;

	// Make sure we have a valid post status
	if ( !is_array( $post_status ) )
		$post_status = explode( ',', $post_status );
	if ( array_diff( $post_status, get_post_stati() ) )
		return false;

	$cache = array();
	$key = md5( serialize( compact(array_keys($defaults)) ) );
	if ( $cache = wp_cache_get( 'get_pages', 'posts' ) ) {
		if ( is_array($cache) && isset( $cache[ $key ] ) ) {
			$pages = apply_filters('get_pages', $cache[ $key ], $r );
			return $pages;
		}
	}

	if ( !is_array($cache) )
		$cache = array();

	$inclusions = '';
	if ( !empty($include) ) {
		$child_of = 0; //ignore child_of, parent, exclude, meta_key, and meta_value params if using include
		$parent = -1;
		$exclude = '';
		$meta_key = '';
		$meta_value = '';
		$hierarchical = false;
		$incpages = wp_parse_id_list( $include );
		if ( ! empty( $incpages ) ) {
			foreach ( $incpages as $incpage ) {
				if (empty($inclusions))
					$inclusions = $wpdb->prepare(' AND ( ID = %d ', $incpage);
				else
					$inclusions .= $wpdb->prepare(' OR ID = %d ', $incpage);
			}
		}
	}
	if (!empty($inclusions))
		$inclusions .= ')';

	$exclusions = '';
	if ( !empty($exclude) ) {
		$expages = wp_parse_id_list( $exclude );
		if ( ! empty( $expages ) ) {
			foreach ( $expages as $expage ) {
				if (empty($exclusions))
					$exclusions = $wpdb->prepare(' AND ( ID <> %d ', $expage);
				else
					$exclusions .= $wpdb->prepare(' AND ID <> %d ', $expage);
			}
		}
	}
	if (!empty($exclusions))
		$exclusions .= ')';

	$author_query = '';
	if (!empty($authors)) {
		$post_authors = preg_split('/[\s,]+/',$authors);

		if ( ! empty( $post_authors ) ) {
			foreach ( $post_authors as $post_author ) {
				//Do we have an author id or an author login?
				if ( 0 == intval($post_author) ) {
					$post_author = get_user_by('login', $post_author);
					if ( empty($post_author) )
						continue;
					if ( empty($post_author->ID) )
						continue;
					$post_author = $post_author->ID;
				}

				if ( '' == $author_query )
					$author_query = $wpdb->prepare(' post_author = %d ', $post_author);
				else
					$author_query .= $wpdb->prepare(' OR post_author = %d ', $post_author);
			}
			if ( '' != $author_query )
				$author_query = " AND ($author_query)";
		}
	}

	$join = '';
	$where = "$exclusions $inclusions ";
	if ( ! empty( $meta_key ) || ! empty( $meta_value ) ) {
		$join = " LEFT JOIN $wpdb->postmeta ON ( $wpdb->posts.ID = $wpdb->postmeta.post_id )";

		// meta_key and meta_value might be slashed
		$meta_key = stripslashes($meta_key);
		$meta_value = stripslashes($meta_value);
		if ( ! empty( $meta_key ) )
			$where .= $wpdb->prepare(" AND $wpdb->postmeta.meta_key = %s", $meta_key);
		if ( ! empty( $meta_value ) )
			$where .= $wpdb->prepare(" AND $wpdb->postmeta.meta_value = %s", $meta_value);

	}

	if ( $parent >= 0 )
		$where .= $wpdb->prepare(' AND post_parent = %d ', $parent);

	if ( 1 == count( $post_status ) ) {
		$where_post_type = $wpdb->prepare( "post_type = %s AND post_status = %s", $post_type, array_shift( $post_status ) );
	} else {
		$post_status = implode( "', '", $post_status );
		$where_post_type = $wpdb->prepare( "post_type = %s AND post_status IN ('$post_status')", $post_type );
	}

	$orderby_array = array();
	$allowed_keys = array('author', 'post_author', 'date', 'post_date', 'title', 'post_title', 'name', 'post_name', 'modified',
						  'post_modified', 'modified_gmt', 'post_modified_gmt', 'menu_order', 'parent', 'post_parent',
						  'ID', 'rand', 'comment_count');
	foreach ( explode( ',', $sort_column ) as $orderby ) {
		$orderby = trim( $orderby );
		if ( !in_array( $orderby, $allowed_keys ) )
			continue;

		switch ( $orderby ) {
			case 'menu_order':
				break;
			case 'ID':
				$orderby = "$wpdb->posts.ID";
				break;
			case 'rand':
				$orderby = 'RAND()';
				break;
			case 'comment_count':
				$orderby = "$wpdb->posts.comment_count";
				break;
			default:
				if ( 0 === strpos( $orderby, 'post_' ) )
					$orderby = "$wpdb->posts." . $orderby;
				else
					$orderby = "$wpdb->posts.post_" . $orderby;
		}

		$orderby_array[] = $orderby;

	}
	$sort_column = ! empty( $orderby_array ) ? implode( ',', $orderby_array ) : "$wpdb->posts.post_title";

	$sort_order = strtoupper( $sort_order );
	if ( '' !== $sort_order && !in_array( $sort_order, array( 'ASC', 'DESC' ) ) )
		$sort_order = 'ASC';

	$query = "SELECT * FROM $wpdb->posts $join WHERE ($where_post_type) $where ";
	$query .= $author_query;
	$query .= " ORDER BY " . $sort_column . " " . $sort_order ;

	if ( !empty($number) )
		$query .= ' LIMIT ' . $offset . ',' . $number;

	$pages = $wpdb->get_results($query);

	if ( empty($pages) ) {
		$pages = apply_filters('get_pages', array(), $r);
		return $pages;
	}

	// Sanitize before caching so it'll only get done once
	$num_pages = count($pages);
	for ($i = 0; $i < $num_pages; $i++) {
		$pages[$i] = sanitize_post($pages[$i], 'raw');
	}

	// Update cache.
	update_post_cache( $pages );

	if ( $child_of || $hierarchical )
		$pages = & get_page_children($child_of, $pages);

	if ( !empty($exclude_tree) ) {
		$exclude = (int) $exclude_tree;
		$children = get_page_children($exclude, $pages);
		$excludes = array();
		foreach ( $children as $child )
			$excludes[] = $child->ID;
		$excludes[] = $exclude;
		$num_pages = count($pages);
		for ( $i = 0; $i < $num_pages; $i++ ) {
			if ( in_array($pages[$i]->ID, $excludes) )
				unset($pages[$i]);
		}
	}

	$cache[ $key ] = $pages;
	wp_cache_set( 'get_pages', $cache, 'posts' );

	$pages = apply_filters('get_pages', $pages, $r);

	return $pages;
}

//
// Attachment functions
//

/**
 * Check if the attachment URI is local one and is really an attachment.
 *
 * @since 2.0.0
 *
 * @param string $url URL to check
 * @return bool True on success, false on failure.
 */
function is_local_attachment($url) {
	if (strpos($url, home_url()) === false)
		return false;
	if (strpos($url, home_url('/?attachment_id=')) !== false)
		return true;
	if ( $id = url_to_postid($url) ) {
		$post = & get_post($id);
		if ( 'attachment' == $post->post_type )
			return true;
	}
	return false;
}

/**
 * Insert an attachment.
 *
 * If you set the 'ID' in the $object parameter, it will mean that you are
 * updating and attempt to update the attachment. You can also set the
 * attachment name or title by setting the key 'post_name' or 'post_title'.
 *
 * You can set the dates for the attachment manually by setting the 'post_date'
 * and 'post_date_gmt' keys' values.
 *
 * By default, the comments will use the default settings for whether the
 * comments are allowed. You can close them manually or keep them open by
 * setting the value for the 'comment_status' key.
 *
 * The $object parameter can have the following:
 *     'post_status'   - Default is 'draft'. Can not be overridden, set the same as parent post.
 *     'post_type'     - Default is 'post', will be set to attachment. Can not override.
 *     'post_author'   - Default is current user ID. The ID of the user, who added the attachment.
 *     'ping_status'   - Default is the value in default ping status option. Whether the attachment
 *                       can accept pings.
 *     'post_parent'   - Default is 0. Can use $parent parameter or set this for the post it belongs
 *                       to, if any.
 *     'menu_order'    - Default is 0. The order it is displayed.
 *     'to_ping'       - Whether to ping.
 *     'pinged'        - Default is empty string.
 *     'post_password' - Default is empty string. The password to access the attachment.
 *     'guid'          - Global Unique ID for referencing the attachment.
 *     'post_content_filtered' - Attachment post content filtered.
 *     'post_excerpt'  - Attachment excerpt.
 *
 * @since 2.0.0
 * @uses $wpdb
 * @uses $user_ID
 * @uses do_action() Calls 'edit_attachment' on $post_ID if this is an update.
 * @uses do_action() Calls 'add_attachment' on $post_ID if this is not an update.
 *
 * @param string|array $object Arguments to override defaults.
 * @param string $file Optional filename.
 * @param int $parent Parent post ID.
 * @return int Attachment ID.
 */
function wp_insert_attachment($object, $file = false, $parent = 0) {
	global $wpdb, $user_ID;

	$defaults = array('post_status' => 'inherit', 'post_type' => 'post', 'post_author' => $user_ID,
		'ping_status' => get_option('default_ping_status'), 'post_parent' => 0,
		'menu_order' => 0, 'to_ping' =>  '', 'pinged' => '', 'post_password' => '',
		'guid' => '', 'post_content_filtered' => '', 'post_excerpt' => '', 'import_id' => 0, 'context' => '');

	$object = wp_parse_args($object, $defaults);
	if ( !empty($parent) )
		$object['post_parent'] = $parent;

	unset( $object[ 'filter' ] );

	$object = sanitize_post($object, 'db');

	// export array as variables
	extract($object, EXTR_SKIP);

	if ( empty($post_author) )
		$post_author = $user_ID;

	$post_type = 'attachment';

	if ( ! in_array( $post_status, array( 'inherit', 'private' ) ) )
		$post_status = 'inherit';

	// Make sure we set a valid category.
	if ( !isset($post_category) || 0 == count($post_category) || !is_array($post_category) ) {
		// 'post' requires at least one category.
		if ( 'post' == $post_type )
			$post_category = array( get_option('default_category') );
		else
			$post_category = array();
	}

	// Are we updating or creating?
	if ( !empty($ID) ) {
		$update = true;
		$post_ID = (int) $ID;
	} else {
		$update = false;
		$post_ID = 0;
	}

	// Create a valid post name.
	if ( empty($post_name) )
		$post_name = sanitize_title($post_title);
	else
		$post_name = sanitize_title($post_name);

	// expected_slashed ($post_name)
	$post_name = wp_unique_post_slug($post_name, $post_ID, $post_status, $post_type, $post_parent);

	if ( empty($post_date) )
		$post_date = current_time('mysql');
	if ( empty($post_date_gmt) )
		$post_date_gmt = current_time('mysql', 1);

	if ( empty($post_modified) )
		$post_modified = $post_date;
	if ( empty($post_modified_gmt) )
		$post_modified_gmt = $post_date_gmt;

	if ( empty($comment_status) ) {
		if ( $update )
			$comment_status = 'closed';
		else
			$comment_status = get_option('default_comment_status');
	}
	if ( empty($ping_status) )
		$ping_status = get_option('default_ping_status');

	if ( isset($to_ping) )
		$to_ping = preg_replace('|\s+|', "\n", $to_ping);
	else
		$to_ping = '';

	if ( isset($post_parent) )
		$post_parent = (int) $post_parent;
	else
		$post_parent = 0;

	if ( isset($menu_order) )
		$menu_order = (int) $menu_order;
	else
		$menu_order = 0;

	if ( !isset($post_password) )
		$post_password = '';

	if ( ! isset($pinged) )
		$pinged = '';

	// expected_slashed (everything!)
	$data = compact( array( 'post_author', 'post_date', 'post_date_gmt', 'post_content', 'post_content_filtered', 'post_title', 'post_excerpt', 'post_status', 'post_type', 'comment_status', 'ping_status', 'post_password', 'post_name', 'to_ping', 'pinged', 'post_modified', 'post_modified_gmt', 'post_parent', 'menu_order', 'post_mime_type', 'guid' ) );
	$data = stripslashes_deep( $data );

	if ( $update ) {
		$wpdb->update( $wpdb->posts, $data, array( 'ID' => $post_ID ) );
	} else {
		// If there is a suggested ID, use it if not already present
		if ( !empty($import_id) ) {
			$import_id = (int) $import_id;
			if ( ! $wpdb->get_var( $wpdb->prepare("SELECT ID FROM $wpdb->posts WHERE ID = %d", $import_id) ) ) {
				$data['ID'] = $import_id;
			}
		}

		$wpdb->insert( $wpdb->posts, $data );
		$post_ID = (int) $wpdb->insert_id;
	}

	if ( empty($post_name) ) {
		$post_name = sanitize_title($post_title, $post_ID);
		$wpdb->update( $wpdb->posts, compact("post_name"), array( 'ID' => $post_ID ) );
	}

	wp_set_post_categories($post_ID, $post_category);

	if ( $file )
		update_attached_file( $post_ID, $file );

	clean_post_cache( $post_ID );

	if ( ! empty( $context ) )
		add_post_meta( $post_ID, '_wp_attachment_context', $context, true );

	if ( $update) {
		do_action('edit_attachment', $post_ID);
	} else {
		do_action('add_attachment', $post_ID);
	}

	return $post_ID;
}

/**
 * Trashes or deletes an attachment.
 *
 * When an attachment is permanently deleted, the file will also be removed.
 * Deletion removes all post meta fields, taxonomy, comments, etc. associated
 * with the attachment (except the main post).
 *
 * The attachment is moved to the trash instead of permanently deleted unless trash
 * for media is disabled, item is already in the trash, or $force_delete is true.
 *
 * @since 2.0.0
 * @uses $wpdb
 * @uses do_action() Calls 'delete_attachment' hook on Attachment ID.
 *
 * @param int $post_id Attachment ID.
 * @param bool $force_delete Whether to bypass trash and force deletion. Defaults to false.
 * @return mixed False on failure. Post data on success.
 */
function wp_delete_attachment( $post_id, $force_delete = false ) {
	global $wpdb;

	if ( !$post = $wpdb->get_row( $wpdb->prepare("SELECT * FROM $wpdb->posts WHERE ID = %d", $post_id) ) )
		return $post;

	if ( 'attachment' != $post->post_type )
		return false;

	if ( !$force_delete && EMPTY_TRASH_DAYS && MEDIA_TRASH && 'trash' != $post->post_status )
		return wp_trash_post( $post_id );

	delete_post_meta($post_id, '_wp_trash_meta_status');
	delete_post_meta($post_id, '_wp_trash_meta_time');

	$meta = wp_get_attachment_metadata( $post_id );
	$backup_sizes = get_post_meta( $post->ID, '_wp_attachment_backup_sizes', true );
	$file = get_attached_file( $post_id );

	if ( is_multisite() )
		delete_transient( 'dirsize_cache' );

	do_action('delete_attachment', $post_id);

	wp_delete_object_term_relationships($post_id, array('category', 'post_tag'));
	wp_delete_object_term_relationships($post_id, get_object_taxonomies($post->post_type));

	delete_metadata( 'post', null, '_thumbnail_id', $post_id, true ); // delete all for any posts.

	$comment_ids = $wpdb->get_col( $wpdb->prepare( "SELECT comment_ID FROM $wpdb->comments WHERE comment_post_ID = %d", $post_id ));
	foreach ( $comment_ids as $comment_id )
		wp_delete_comment( $comment_id, true );

	$post_meta_ids = $wpdb->get_col( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d ", $post_id ));
	foreach ( $post_meta_ids as $mid )
		delete_metadata_by_mid( 'post', $mid );

	do_action( 'delete_post', $post_id );
	$wpdb->delete( $wpdb->posts, array( 'ID' => $post_id ) );
	do_action( 'deleted_post', $post_id );

	$uploadpath = wp_upload_dir();

	if ( ! empty($meta['thumb']) ) {
		// Don't delete the thumb if another attachment uses it
		if (! $wpdb->get_row( $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE meta_key = '_wp_attachment_metadata' AND meta_value LIKE %s AND post_id <> %d", '%' . $meta['thumb'] . '%', $post_id)) ) {
			$thumbfile = str_replace(basename($file), $meta['thumb'], $file);
			$thumbfile = apply_filters('wp_delete_file', $thumbfile);
			@ unlink( path_join($uploadpath['basedir'], $thumbfile) );
		}
	}

	// remove intermediate and backup images if there are any
	foreach ( get_intermediate_image_sizes() as $size ) {
		if ( $intermediate = image_get_intermediate_size($post_id, $size) ) {
			$intermediate_file = apply_filters('wp_delete_file', $intermediate['path']);
			@ unlink( path_join($uploadpath['basedir'], $intermediate_file) );
		}
	}

	if ( is_array($backup_sizes) ) {
		foreach ( $backup_sizes as $size ) {
			$del_file = path_join( dirname($meta['file']), $size['file'] );
			$del_file = apply_filters('wp_delete_file', $del_file);
			@ unlink( path_join($uploadpath['basedir'], $del_file) );
		}
	}

	$file = apply_filters('wp_delete_file', $file);

	if ( ! empty($file) )
		@ unlink($file);

	clean_post_cache( $post );

	return $post;
}

/**
 * Retrieve attachment meta field for attachment ID.
 *
 * @since 2.1.0
 *
 * @param int $post_id Attachment ID
 * @param bool $unfiltered Optional, default is false. If true, filters are not run.
 * @return string|bool Attachment meta field. False on failure.
 */
function wp_get_attachment_metadata( $post_id = 0, $unfiltered = false ) {
	$post_id = (int) $post_id;
	if ( !$post =& get_post( $post_id ) )
		return false;

	$data = get_post_meta( $post->ID, '_wp_attachment_metadata', true );

	if ( $unfiltered )
		return $data;

	return apply_filters( 'wp_get_attachment_metadata', $data, $post->ID );
}

/**
 * Update metadata for an attachment.
 *
 * @since 2.1.0
 *
 * @param int $post_id Attachment ID.
 * @param array $data Attachment data.
 * @return int
 */
function wp_update_attachment_metadata( $post_id, $data ) {
	$post_id = (int) $post_id;
	if ( !$post =& get_post( $post_id ) )
		return false;

	$data = apply_filters( 'wp_update_attachment_metadata', $data, $post->ID );

	return update_post_meta( $post->ID, '_wp_attachment_metadata', $data);
}

/**
 * Retrieve the URL for an attachment.
 *
 * @since 2.1.0
 *
 * @param int $post_id Attachment ID.
 * @return string
 */
function wp_get_attachment_url( $post_id = 0 ) {
	$post_id = (int) $post_id;
	if ( !$post =& get_post( $post_id ) )
		return false;

	if ( 'attachment' != $post->post_type )
		return false;

	$url = '';
	if ( $file = get_post_meta( $post->ID, '_wp_attached_file', true) ) { //Get attached file
		if ( ($uploads = wp_upload_dir()) && false === $uploads['error'] ) { //Get upload directory
			if ( 0 === strpos($file, $uploads['basedir']) ) //Check that the upload base exists in the file location
				$url = str_replace($uploads['basedir'], $uploads['baseurl'], $file); //replace file location with url location
			elseif ( false !== strpos($file, 'wp-content/uploads') )
				$url = $uploads['baseurl'] . substr( $file, strpos($file, 'wp-content/uploads') + 18 );
			else
				$url = $uploads['baseurl'] . "/$file"; //Its a newly uploaded file, therefor $file is relative to the basedir.
		}
	}

	if ( empty($url) ) //If any of the above options failed, Fallback on the GUID as used pre-2.7, not recommended to rely upon this.
		$url = get_the_guid( $post->ID );

	$url = apply_filters( 'wp_get_attachment_url', $url, $post->ID );

	if ( empty( $url ) )
		return false;

	return $url;
}

/**
 * Retrieve thumbnail for an attachment.
 *
 * @since 2.1.0
 *
 * @param int $post_id Attachment ID.
 * @return mixed False on failure. Thumbnail file path on success.
 */
function wp_get_attachment_thumb_file( $post_id = 0 ) {
	$post_id = (int) $post_id;
	if ( !$post =& get_post( $post_id ) )
		return false;
	if ( !is_array( $imagedata = wp_get_attachment_metadata( $post->ID ) ) )
		return false;

	$file = get_attached_file( $post->ID );

	if ( !empty($imagedata['thumb']) && ($thumbfile = str_replace(basename($file), $imagedata['thumb'], $file)) && file_exists($thumbfile) )
		return apply_filters( 'wp_get_attachment_thumb_file', $thumbfile, $post->ID );
	return false;
}

/**
 * Retrieve URL for an attachment thumbnail.
 *
 * @since 2.1.0
 *
 * @param int $post_id Attachment ID
 * @return string|bool False on failure. Thumbnail URL on success.
 */
function wp_get_attachment_thumb_url( $post_id = 0 ) {
	$post_id = (int) $post_id;
	if ( !$post =& get_post( $post_id ) )
		return false;
	if ( !$url = wp_get_attachment_url( $post->ID ) )
		return false;

	$sized = image_downsize( $post_id, 'thumbnail' );
	if ( $sized )
		return $sized[0];

	if ( !$thumb = wp_get_attachment_thumb_file( $post->ID ) )
		return false;

	$url = str_replace(basename($url), basename($thumb), $url);

	return apply_filters( 'wp_get_attachment_thumb_url', $url, $post->ID );
}

/**
 * Check if the attachment is an image.
 *
 * @since 2.1.0
 *
 * @param int $post_id Attachment ID
 * @return bool
 */
function wp_attachment_is_image( $post_id = 0 ) {
	$post_id = (int) $post_id;
	if ( !$post =& get_post( $post_id ) )
		return false;

	if ( !$file = get_attached_file( $post->ID ) )
		return false;

	$ext = preg_match('/\.([^.]+)$/', $file, $matches) ? strtolower($matches[1]) : false;

	$image_exts = array('jpg', 'jpeg', 'gif', 'png');

	if ( 'image/' == substr($post->post_mime_type, 0, 6) || $ext && 'import' == $post->post_mime_type && in_array($ext, $image_exts) )
		return true;
	return false;
}

/**
 * Retrieve the icon for a MIME type.
 *
 * @since 2.1.0
 *
 * @param string|int $mime MIME type or attachment ID.
 * @return string|bool
 */
function wp_mime_type_icon( $mime = 0 ) {
	if ( !is_numeric($mime) )
		$icon = wp_cache_get("mime_type_icon_$mime");
	if ( empty($icon) ) {
		$post_id = 0;
		$post_mimes = array();
		if ( is_numeric($mime) ) {
			$mime = (int) $mime;
			if ( $post =& get_post( $mime ) ) {
				$post_id = (int) $post->ID;
				$ext = preg_replace('/^.+?\.([^.]+)$/', '$1', $post->guid);
				if ( !empty($ext) ) {
					$post_mimes[] = $ext;
					if ( $ext_type = wp_ext2type( $ext ) )
						$post_mimes[] = $ext_type;
				}
				$mime = $post->post_mime_type;
			} else {
				$mime = 0;
			}
		} else {
			$post_mimes[] = $mime;
		}

		$icon_files = wp_cache_get('icon_files');

		if ( !is_array($icon_files) ) {
			$icon_dir = apply_filters( 'icon_dir', ABSPATH . WPINC . '/images/crystal' );
			$icon_dir_uri = apply_filters( 'icon_dir_uri', includes_url('images/crystal') );
			$dirs = apply_filters( 'icon_dirs', array($icon_dir => $icon_dir_uri) );
			$icon_files = array();
			while ( $dirs ) {
				$keys = array_keys( $dirs );
				$dir = array_shift( $keys );
				$uri = array_shift($dirs);
				if ( $dh = opendir($dir) ) {
					while ( false !== $file = readdir($dh) ) {
						$file = basename($file);
						if ( substr($file, 0, 1) == '.' )
							continue;
						if ( !in_array(strtolower(substr($file, -4)), array('.png', '.gif', '.jpg') ) ) {
							if ( is_dir("$dir/$file") )
								$dirs["$dir/$file"] = "$uri/$file";
							continue;
						}
						$icon_files["$dir/$file"] = "$uri/$file";
					}
					closedir($dh);
				}
			}
			wp_cache_set('icon_files', $icon_files, 600);
		}

		// Icon basename - extension = MIME wildcard
		foreach ( $icon_files as $file => $uri )
			$types[ preg_replace('/^([^.]*).*$/', '$1', basename($file)) ] =& $icon_files[$file];

		if ( ! empty($mime) ) {
			$post_mimes[] = substr($mime, 0, strpos($mime, '/'));
			$post_mimes[] = substr($mime, strpos($mime, '/') + 1);
			$post_mimes[] = str_replace('/', '_', $mime);
		}

		$matches = wp_match_mime_types(array_keys($types), $post_mimes);
		$matches['default'] = array('default');

		foreach ( $matches as $match => $wilds ) {
			if ( isset($types[$wilds[0]])) {
				$icon = $types[$wilds[0]];
				if ( !is_numeric($mime) )
					wp_cache_set("mime_type_icon_$mime", $icon);
				break;
			}
		}
	}

	return apply_filters( 'wp_mime_type_icon', $icon, $mime, $post_id ); // Last arg is 0 if function pass mime type.
}

/**
 * Checked for changed slugs for published post objects and save the old slug.
 *
 * The function is used when a post object of any type is updated,
 * by comparing the current and previous post objects.
 *
 * If the slug was changed and not already part of the old slugs then it will be
 * added to the post meta field ('_wp_old_slug') for storing old slugs for that
 * post.
 *
 * The most logically usage of this function is redirecting changed post objects, so
 * that those that linked to an changed post will be redirected to the new post.
 *
 * @since 2.1.0
 *
 * @param int $post_id Post ID.
 * @param object $post The Post Object
 * @param object $post_before The Previous Post Object
 * @return int Same as $post_id
 */
function wp_check_for_changed_slugs($post_id, $post, $post_before) {
	// dont bother if it hasnt changed
	if ( $post->post_name == $post_before->post_name )
		return;

	// we're only concerned with published, non-hierarchical objects
	if ( $post->post_status != 'publish' || is_post_type_hierarchical( $post->post_type ) )
		return;

	$old_slugs = (array) get_post_meta($post_id, '_wp_old_slug');

	// if we haven't added this old slug before, add it now
	if ( !empty( $post_before->post_name ) && !in_array($post_before->post_name, $old_slugs) )
		add_post_meta($post_id, '_wp_old_slug', $post_before->post_name);

	// if the new slug was used previously, delete it from the list
	if ( in_array($post->post_name, $old_slugs) )
		delete_post_meta($post_id, '_wp_old_slug', $post->post_name);
}

/**
 * Retrieve the private post SQL based on capability.
 *
 * This function provides a standardized way to appropriately select on the
 * post_status of a post type. The function will return a piece of SQL code
 * that can be added to a WHERE clause; this SQL is constructed to allow all
 * published posts, and all private posts to which the user has access.
 *
 * @since 2.2.0
 *
 * @uses $user_ID
 *
 * @param string $post_type currently only supports 'post' or 'page'.
 * @return string SQL code that can be added to a where clause.
 */
function get_private_posts_cap_sql( $post_type ) {
	return get_posts_by_author_sql( $post_type, false );
}

/**
 * Retrieve the post SQL based on capability, author, and type.
 *
 * @see get_private_posts_cap_sql() for full description.
 *
 * @since 3.0.0
 * @param string $post_type Post type.
 * @param bool $full Optional. Returns a full WHERE statement instead of just an 'andalso' term.
 * @param int $post_author Optional. Query posts having a single author ID.
 * @return string SQL WHERE code that can be added to a query.
 */
function get_posts_by_author_sql( $post_type, $full = true, $post_author = null ) {
	global $user_ID, $wpdb;

	// Private posts
	$post_type_obj = get_post_type_object( $post_type );
	if ( ! $post_type_obj )
		return $full ? 'WHERE 1 = 0' : ' 1 = 0 ';

	// This hook is deprecated. Why you'd want to use it, I dunno.
	if ( ! $cap = apply_filters( 'pub_priv_sql_capability', '' ) )
		$cap = $post_type_obj->cap->read_private_posts;

	if ( $full ) {
		if ( null === $post_author ) {
			$sql = $wpdb->prepare( 'WHERE post_type = %s AND ', $post_type );
		} else {
			$sql = $wpdb->prepare( 'WHERE post_author = %d AND post_type = %s AND ', $post_author, $post_type );
		}
	} else {
		$sql = '';
	}

	$sql .= "(post_status = 'publish'";

	if ( current_user_can( $cap ) ) {
		// Does the user have the capability to view private posts? Guess so.
		$sql .= " OR post_status = 'private'";
	} elseif ( is_user_logged_in() ) {
		// Users can view their own private posts.
		$id = (int) $user_ID;
		if ( null === $post_author || ! $full ) {
			$sql .= " OR post_status = 'private' AND post_author = $id";
		} elseif ( $id == (int) $post_author ) {
			$sql .= " OR post_status = 'private'";
		} // else none
	} // else none

	$sql .= ')';

	return $sql;
}

/**
 * Retrieve the date that the last post was published.
 *
 * The server timezone is the default and is the difference between GMT and
 * server time. The 'blog' value is the date when the last post was posted. The
 * 'gmt' is when the last post was posted in GMT formatted date.
 *
 * @since 0.71
 *
 * @uses apply_filters() Calls 'get_lastpostdate' filter
 *
 * @param string $timezone The location to get the time. Can be 'gmt', 'blog', or 'server'.
 * @return string The date of the last post.
 */
function get_lastpostdate($timezone = 'server') {
	return apply_filters( 'get_lastpostdate', _get_last_post_time( $timezone, 'date' ), $timezone );
}

/**
 * Retrieve last post modified date depending on timezone.
 *
 * The server timezone is the default and is the difference between GMT and
 * server time. The 'blog' value is just when the last post was modified. The
 * 'gmt' is when the last post was modified in GMT time.
 *
 * @since 1.2.0
 * @uses apply_filters() Calls 'get_lastpostmodified' filter
 *
 * @param string $timezone The location to get the time. Can be 'gmt', 'blog', or 'server'.
 * @return string The date the post was last modified.
 */
function get_lastpostmodified($timezone = 'server') {
	$lastpostmodified = _get_last_post_time( $timezone, 'modified' );

	$lastpostdate = get_lastpostdate($timezone);
	if ( $lastpostdate > $lastpostmodified )
		$lastpostmodified = $lastpostdate;

	return apply_filters( 'get_lastpostmodified', $lastpostmodified, $timezone );
}

/**
 * Retrieve latest post date data based on timezone.
 *
 * @access private
 * @since 3.1.0
 *
 * @param string $timezone The location to get the time. Can be 'gmt', 'blog', or 'server'.
 * @param string $field Field to check. Can be 'date' or 'modified'.
 * @return string The date.
 */
function _get_last_post_time( $timezone, $field ) {
	global $wpdb;

	if ( !in_array( $field, array( 'date', 'modified' ) ) )
		return false;

	$timezone = strtolower( $timezone );

	$key = "lastpost{$field}:$timezone";

	$date = wp_cache_get( $key, 'timeinfo' );

	if ( !$date ) {
		$add_seconds_server = date('Z');

		$post_types = get_post_types( array( 'public' => true ) );
		array_walk( $post_types, array( &$wpdb, 'escape_by_ref' ) );
		$post_types = "'" . implode( "', '", $post_types ) . "'";

		switch ( $timezone ) {
			case 'gmt':
				$date = $wpdb->get_var("SELECT post_{$field}_gmt FROM $wpdb->posts WHERE post_status = 'publish' AND post_type IN ({$post_types}) ORDER BY post_{$field}_gmt DESC LIMIT 1");
				break;
			case 'blog':
				$date = $wpdb->get_var("SELECT post_{$field} FROM $wpdb->posts WHERE post_status = 'publish' AND post_type IN ({$post_types}) ORDER BY post_{$field}_gmt DESC LIMIT 1");
				break;
			case 'server':
				$date = $wpdb->get_var("SELECT DATE_ADD(post_{$field}_gmt, INTERVAL '$add_seconds_server' SECOND) FROM $wpdb->posts WHERE post_status = 'publish' AND post_type IN ({$post_types}) ORDER BY post_{$field}_gmt DESC LIMIT 1");
				break;
		}

		if ( $date )
			wp_cache_set( $key, $date, 'timeinfo' );
	}

	return $date;
}

/**
 * Updates posts in cache.
 *
 * @package WordPress
 * @subpackage Cache
 * @since 1.5.1
 *
 * @param array $posts Array of post objects
 */
function update_post_cache( &$posts ) {
	if ( ! $posts )
		return;

	foreach ( $posts as $post )
		wp_cache_add( $post->ID, $post, 'posts' );
}

/**
 * Will clean the post in the cache.
 *
 * Cleaning means delete from the cache of the post. Will call to clean the term
 * object cache associated with the post ID.
 *
 * clean_post_cache() will call itself recursively for each child post.
 *
 * This function not run if $_wp_suspend_cache_invalidation is not empty. See
 * wp_suspend_cache_invalidation().
 *
 * @package WordPress
 * @subpackage Cache
 * @since 2.0.0
 *
 * @uses do_action() Calls 'clean_post_cache' on $id before adding children (if any).
 *
 * @param object|int $post The post object or ID to remove from the cache
 */
function clean_post_cache( $post ) {
	global $_wp_suspend_cache_invalidation, $wpdb;

	if ( ! empty( $_wp_suspend_cache_invalidation ) )
		return;

	$post = get_post( $post );
	if ( empty( $post ) )
		return;

	wp_cache_delete( $post->ID, 'posts' );
	wp_cache_delete( $post->ID, 'post_meta' );

	clean_object_term_cache( $post->ID, $post->post_type );

	wp_cache_delete( 'wp_get_archives', 'general' );

	do_action( 'clean_post_cache', $post->ID, $post );

	if ( 'page' == $post->post_type ) {
		wp_cache_delete( 'all_page_ids', 'posts' );
		wp_cache_delete( 'get_pages', 'posts' );
		do_action( 'clean_page_cache', $post->ID );
	}

	if ( $children = $wpdb->get_results( $wpdb->prepare("SELECT ID, post_type FROM $wpdb->posts WHERE post_parent = %d", $post->ID) ) ) {
		foreach ( $children as $child ) {
			// Loop detection
			if ( $child->ID == $post->ID )
				continue;
			clean_post_cache( $child );
		}
	}

	if ( is_multisite() )
		wp_cache_delete( $wpdb->blogid . '-' . $post->ID, 'global-posts' );
}

/**
 * Call major cache updating functions for list of Post objects.
 *
 * @package WordPress
 * @subpackage Cache
 * @since 1.5.0
 *
 * @uses $wpdb
 * @uses update_post_cache()
 * @uses update_object_term_cache()
 * @uses update_postmeta_cache()
 *
 * @param array $posts Array of Post objects
 * @param string $post_type The post type of the posts in $posts. Default is 'post'.
 * @param bool $update_term_cache Whether to update the term cache. Default is true.
 * @param bool $update_meta_cache Whether to update the meta cache. Default is true.
 */
function update_post_caches(&$posts, $post_type = 'post', $update_term_cache = true, $update_meta_cache = true) {
	// No point in doing all this work if we didn't match any posts.
	if ( !$posts )
		return;

	update_post_cache($posts);

	$post_ids = array();
	foreach ( $posts as $post )
		$post_ids[] = $post->ID;

	if ( empty($post_type) )
		$post_type = 'post';

	if ( $update_term_cache ) {
		if ( is_array($post_type) ) {
			$ptypes = $post_type;
		} elseif ( 'any' == $post_type ) {
			// Just use the post_types in the supplied posts.
			foreach ( $posts as $post )
				$ptypes[] = $post->post_type;
			$ptypes = array_unique($ptypes);
		} else {
			$ptypes = array($post_type);
		}

		if ( ! empty($ptypes) )
			update_object_term_cache($post_ids, $ptypes);
	}

	if ( $update_meta_cache )
		update_postmeta_cache($post_ids);
}

/**
 * Updates metadata cache for list of post IDs.
 *
 * Performs SQL query to retrieve the metadata for the post IDs and updates the
 * metadata cache for the posts. Therefore, the functions, which call this
 * function, do not need to perform SQL queries on their own.
 *
 * @package WordPress
 * @subpackage Cache
 * @since 2.1.0
 *
 * @uses $wpdb
 *
 * @param array $post_ids List of post IDs.
 * @return bool|array Returns false if there is nothing to update or an array of metadata.
 */
function update_postmeta_cache($post_ids) {
	return update_meta_cache('post', $post_ids);
}

/**
 * Will clean the attachment in the cache.
 *
 * Cleaning means delete from the cache. Optionally will clean the term
 * object cache associated with the attachment ID.
 *
 * This function will not run if $_wp_suspend_cache_invalidation is not empty. See
 * wp_suspend_cache_invalidation().
 *
 * @package WordPress
 * @subpackage Cache
 * @since 3.0.0
 *
 * @uses do_action() Calls 'clean_attachment_cache' on $id.
 *
 * @param int $id The attachment ID in the cache to clean
 * @param bool $clean_terms optional. Whether to clean terms cache
 */
function clean_attachment_cache($id, $clean_terms = false) {
	global $_wp_suspend_cache_invalidation;

	if ( !empty($_wp_suspend_cache_invalidation) )
		return;

	$id = (int) $id;

	wp_cache_delete($id, 'posts');
	wp_cache_delete($id, 'post_meta');

	if ( $clean_terms )
		clean_object_term_cache($id, 'attachment');

	do_action('clean_attachment_cache', $id);
}

//
// Hooks
//

/**
 * Hook for managing future post transitions to published.
 *
 * @since 2.3.0
 * @access private
 * @uses $wpdb
 * @uses do_action() Calls 'private_to_published' on post ID if this is a 'private_to_published' call.
 * @uses wp_clear_scheduled_hook() with 'publish_future_post' and post ID.
 *
 * @param string $new_status New post status
 * @param string $old_status Previous post status
 * @param object $post Object type containing the post information
 */
function _transition_post_status($new_status, $old_status, $post) {
	global $wpdb;

	if ( $old_status != 'publish' && $new_status == 'publish' ) {
		// Reset GUID if transitioning to publish and it is empty
		if ( '' == get_the_guid($post->ID) )
			$wpdb->update( $wpdb->posts, array( 'guid' => get_permalink( $post->ID ) ), array( 'ID' => $post->ID ) );
		do_action('private_to_published', $post->ID);  // Deprecated, use private_to_publish
	}

	// If published posts changed clear the lastpostmodified cache
	if ( 'publish' == $new_status || 'publish' == $old_status) {
		foreach ( array( 'server', 'gmt', 'blog' ) as $timezone ) {
			wp_cache_delete( "lastpostmodified:$timezone", 'timeinfo' );
			wp_cache_delete( "lastpostdate:$timezone", 'timeinfo' );
		}
	}

	// Always clears the hook in case the post status bounced from future to draft.
	wp_clear_scheduled_hook('publish_future_post', array( $post->ID ) );
}

/**
 * Hook used to schedule publication for a post marked for the future.
 *
 * The $post properties used and must exist are 'ID' and 'post_date_gmt'.
 *
 * @since 2.3.0
 * @access private
 *
 * @param int $deprecated Not used. Can be set to null. Never implemented.
 *   Not marked as deprecated with _deprecated_argument() as it conflicts with
 *   wp_transition_post_status() and the default filter for _future_post_hook().
 * @param object $post Object type containing the post information
 */
function _future_post_hook( $deprecated = '', $post ) {
	wp_clear_scheduled_hook( 'publish_future_post', array( $post->ID ) );
	wp_schedule_single_event( strtotime( get_gmt_from_date( $post->post_date ) . ' GMT') , 'publish_future_post', array( $post->ID ) );
}

/**
 * Hook to schedule pings and enclosures when a post is published.
 *
 * @since 2.3.0
 * @access private
 * @uses $wpdb
 * @uses XMLRPC_REQUEST and APP_REQUEST constants.
 * @uses do_action() Calls 'xmlprc_publish_post' on post ID if XMLRPC_REQUEST is defined.
 * @uses do_action() Calls 'app_publish_post' on post ID if APP_REQUEST is defined.
 *
 * @param int $post_id The ID in the database table of the post being published
 */
function _publish_post_hook($post_id) {
	global $wpdb;

	if ( defined('XMLRPC_REQUEST') )
		do_action('xmlrpc_publish_post', $post_id);
	if ( defined('APP_REQUEST') )
		do_action('app_publish_post', $post_id);

	if ( defined('WP_IMPORTING') )
		return;

	if ( get_option('default_pingback_flag') )
		add_post_meta( $post_id, '_pingme', '1' );
	add_post_meta( $post_id, '_encloseme', '1' );

	wp_schedule_single_event(time(), 'do_pings');
}

/**
 * Hook used to prevent page/post cache from staying dirty when a post is saved.
 *
 * @since 2.3.0
 * @access private
 *
 * @param int $post_id The ID in the database table for the $post
 * @param object $post Object type containing the post information
 */
function _save_post_hook( $post_id, $post ) {
	clean_post_cache( $post );
}

/**
 * Retrieve post ancestors and append to post ancestors property.
 *
 * Will only retrieve ancestors once, if property is already set, then nothing
 * will be done. If there is not a parent post, or post ID and post parent ID
 * are the same then nothing will be done.
 *
 * The parameter is passed by reference, so nothing needs to be returned. The
 * property will be updated and can be referenced after the function is
 * complete. The post parent will be an ancestor and the parent of the post
 * parent will be an ancestor. There will only be two ancestors at the most.
 *
 * @since 2.5.0
 * @access private
 * @uses $wpdb
 *
 * @param object $_post Post data.
 * @return null When nothing needs to be done.
 */
function _get_post_ancestors(&$_post) {
	global $wpdb;

	if ( isset($_post->ancestors) )
		return;

	$_post->ancestors = array();

	if ( empty($_post->post_parent) || $_post->ID == $_post->post_parent )
		return;

	$id = $_post->ancestors[] = (int) $_post->post_parent;
	while ( $ancestor = $wpdb->get_var( $wpdb->prepare("SELECT `post_parent` FROM $wpdb->posts WHERE ID = %d LIMIT 1", $id) ) ) {
		// Loop detection: If the ancestor has been seen before, break.
		if ( ( $ancestor == $_post->ID ) || in_array($ancestor,  $_post->ancestors) )
			break;
		$id = $_post->ancestors[] = (int) $ancestor;
	}
}

/**
 * Determines which fields of posts are to be saved in revisions.
 *
 * Does two things. If passed a post *array*, it will return a post array ready
 * to be inserted into the posts table as a post revision. Otherwise, returns
 * an array whose keys are the post fields to be saved for post revisions.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 * @access private
 * @uses apply_filters() Calls '_wp_post_revision_fields' on 'title', 'content' and 'excerpt' fields.
 *
 * @param array $post Optional a post array to be processed for insertion as a post revision.
 * @param bool $autosave optional Is the revision an autosave?
 * @return array Post array ready to be inserted as a post revision or array of fields that can be versioned.
 */
function _wp_post_revision_fields( $post = null, $autosave = false ) {
	static $fields = false;

	if ( !$fields ) {
		// Allow these to be versioned
		$fields = array(
			'post_title' => __( 'Title' ),
			'post_content' => __( 'Content' ),
			'post_excerpt' => __( 'Excerpt' ),
		);

		// Runs only once
		$fields = apply_filters( '_wp_post_revision_fields', $fields );

		// WP uses these internally either in versioning or elsewhere - they cannot be versioned
		foreach ( array( 'ID', 'post_name', 'post_parent', 'post_date', 'post_date_gmt', 'post_status', 'post_type', 'comment_count', 'post_author' ) as $protect )
			unset( $fields[$protect] );
	}

	if ( !is_array($post) )
		return $fields;

	$return = array();
	foreach ( array_intersect( array_keys( $post ), array_keys( $fields ) ) as $field )
		$return[$field] = $post[$field];

	$return['post_parent']   = $post['ID'];
	$return['post_status']   = 'inherit';
	$return['post_type']     = 'revision';
	$return['post_name']     = $autosave ? "$post[ID]-autosave" : "$post[ID]-revision";
	$return['post_date']     = isset($post['post_modified']) ? $post['post_modified'] : '';
	$return['post_date_gmt'] = isset($post['post_modified_gmt']) ? $post['post_modified_gmt'] : '';

	return $return;
}

/**
 * Saves an already existing post as a post revision.
 *
 * Typically used immediately prior to post updates.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @uses _wp_put_post_revision()
 *
 * @param int $post_id The ID of the post to save as a revision.
 * @return mixed Null or 0 if error, new revision ID, if success.
 */
function wp_save_post_revision( $post_id ) {
	// We do autosaves manually with wp_create_post_autosave()
	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
		return;

	// WP_POST_REVISIONS = 0, false
	if ( ! WP_POST_REVISIONS )
		return;

	if ( !$post = get_post( $post_id, ARRAY_A ) )
		return;

	if ( !post_type_supports($post['post_type'], 'revisions') )
		return;

	$return = _wp_put_post_revision( $post );

	// WP_POST_REVISIONS = true (default), -1
	if ( !is_numeric( WP_POST_REVISIONS ) || WP_POST_REVISIONS < 0 )
		return $return;

	// all revisions and (possibly) one autosave
	$revisions = wp_get_post_revisions( $post_id, array( 'order' => 'ASC' ) );

	// WP_POST_REVISIONS = (int) (# of autosaves to save)
	$delete = count($revisions) - WP_POST_REVISIONS;

	if ( $delete < 1 )
		return $return;

	$revisions = array_slice( $revisions, 0, $delete );

	for ( $i = 0; isset($revisions[$i]); $i++ ) {
		if ( false !== strpos( $revisions[$i]->post_name, 'autosave' ) )
			continue;
		wp_delete_post_revision( $revisions[$i]->ID );
	}

	return $return;
}

/**
 * Retrieve the autosaved data of the specified post.
 *
 * Returns a post object containing the information that was autosaved for the
 * specified post.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @param int $post_id The post ID.
 * @return object|bool The autosaved data or false on failure or when no autosave exists.
 */
function wp_get_post_autosave( $post_id ) {

	if ( !$post = get_post( $post_id ) )
		return false;

	$q = array(
		'name' => "{$post->ID}-autosave",
		'post_parent' => $post->ID,
		'post_type' => 'revision',
		'post_status' => 'inherit'
	);

	// Use WP_Query so that the result gets cached
	$autosave_query = new WP_Query;

	add_action( 'parse_query', '_wp_get_post_autosave_hack' );
	$autosave = $autosave_query->query( $q );
	remove_action( 'parse_query', '_wp_get_post_autosave_hack' );

	if ( $autosave && is_array($autosave) && is_object($autosave[0]) )
		return $autosave[0];

	return false;
}

/**
 * Internally used to hack WP_Query into submission.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @param object $query WP_Query object
 */
function _wp_get_post_autosave_hack( $query ) {
	$query->is_single = false;
}

/**
 * Determines if the specified post is a revision.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @param int|object $post Post ID or post object.
 * @return bool|int False if not a revision, ID of revision's parent otherwise.
 */
function wp_is_post_revision( $post ) {
	if ( !$post = wp_get_post_revision( $post ) )
		return false;
	return (int) $post->post_parent;
}

/**
 * Determines if the specified post is an autosave.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @param int|object $post Post ID or post object.
 * @return bool|int False if not a revision, ID of autosave's parent otherwise
 */
function wp_is_post_autosave( $post ) {
	if ( !$post = wp_get_post_revision( $post ) )
		return false;
	if ( "{$post->post_parent}-autosave" !== $post->post_name )
		return false;
	return (int) $post->post_parent;
}

/**
 * Inserts post data into the posts table as a post revision.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @uses wp_insert_post()
 *
 * @param int|object|array $post Post ID, post object OR post array.
 * @param bool $autosave Optional. Is the revision an autosave?
 * @return mixed Null or 0 if error, new revision ID if success.
 */
function _wp_put_post_revision( $post = null, $autosave = false ) {
	if ( is_object($post) )
		$post = get_object_vars( $post );
	elseif ( !is_array($post) )
		$post = get_post($post, ARRAY_A);
	if ( !$post || empty($post['ID']) )
		return;

	if ( isset($post['post_type']) && 'revision' == $post['post_type'] )
		return new WP_Error( 'post_type', __( 'Cannot create a revision of a revision' ) );

	$post = _wp_post_revision_fields( $post, $autosave );
	$post = add_magic_quotes($post); //since data is from db

	$revision_id = wp_insert_post( $post );
	if ( is_wp_error($revision_id) )
		return $revision_id;

	if ( $revision_id )
		do_action( '_wp_put_post_revision', $revision_id );
	return $revision_id;
}

/**
 * Gets a post revision.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @uses get_post()
 *
 * @param int|object $post Post ID or post object
 * @param string $output Optional. OBJECT, ARRAY_A, or ARRAY_N.
 * @param string $filter Optional sanitation filter. @see sanitize_post()
 * @return mixed Null if error or post object if success
 */
function &wp_get_post_revision(&$post, $output = OBJECT, $filter = 'raw') {
	$null = null;
	if ( !$revision = get_post( $post, OBJECT, $filter ) )
		return $revision;
	if ( 'revision' !== $revision->post_type )
		return $null;

	if ( $output == OBJECT ) {
		return $revision;
	} elseif ( $output == ARRAY_A ) {
		$_revision = get_object_vars($revision);
		return $_revision;
	} elseif ( $output == ARRAY_N ) {
		$_revision = array_values(get_object_vars($revision));
		return $_revision;
	}

	return $revision;
}

/**
 * Restores a post to the specified revision.
 *
 * Can restore a past revision using all fields of the post revision, or only selected fields.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @uses wp_get_post_revision()
 * @uses wp_update_post()
 * @uses do_action() Calls 'wp_restore_post_revision' on post ID and revision ID if wp_update_post()
 *  is successful.
 *
 * @param int|object $revision_id Revision ID or revision object.
 * @param array $fields Optional. What fields to restore from. Defaults to all.
 * @return mixed Null if error, false if no fields to restore, (int) post ID if success.
 */
function wp_restore_post_revision( $revision_id, $fields = null ) {
	if ( !$revision = wp_get_post_revision( $revision_id, ARRAY_A ) )
		return $revision;

	if ( !is_array( $fields ) )
		$fields = array_keys( _wp_post_revision_fields() );

	$update = array();
	foreach( array_intersect( array_keys( $revision ), $fields ) as $field )
		$update[$field] = $revision[$field];

	if ( !$update )
		return false;

	$update['ID'] = $revision['post_parent'];

	$update = add_magic_quotes( $update ); //since data is from db

	$post_id = wp_update_post( $update );
	if ( is_wp_error( $post_id ) )
		return $post_id;

	if ( $post_id )
		do_action( 'wp_restore_post_revision', $post_id, $revision['ID'] );

	return $post_id;
}

/**
 * Deletes a revision.
 *
 * Deletes the row from the posts table corresponding to the specified revision.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @uses wp_get_post_revision()
 * @uses wp_delete_post()
 *
 * @param int|object $revision_id Revision ID or revision object.
 * @return mixed Null or WP_Error if error, deleted post if success.
 */
function wp_delete_post_revision( $revision_id ) {
	if ( !$revision = wp_get_post_revision( $revision_id ) )
		return $revision;

	$delete = wp_delete_post( $revision->ID );
	if ( is_wp_error( $delete ) )
		return $delete;

	if ( $delete )
		do_action( 'wp_delete_post_revision', $revision->ID, $revision );

	return $delete;
}

/**
 * Returns all revisions of specified post.
 *
 * @package WordPress
 * @subpackage Post_Revisions
 * @since 2.6.0
 *
 * @uses get_children()
 *
 * @param int|object $post_id Post ID or post object
 * @return array empty if no revisions
 */
function wp_get_post_revisions( $post_id = 0, $args = null ) {
	if ( ! WP_POST_REVISIONS )
		return array();
	if ( ( !$post = get_post( $post_id ) ) || empty( $post->ID ) )
		return array();

	$defaults = array( 'order' => 'DESC', 'orderby' => 'date' );
	$args = wp_parse_args( $args, $defaults );
	$args = array_merge( $args, array( 'post_parent' => $post->ID, 'post_type' => 'revision', 'post_status' => 'inherit' ) );

	if ( !$revisions = get_children( $args ) )
		return array();
	return $revisions;
}

function _set_preview($post) {

	if ( ! is_object($post) )
		return $post;

	$preview = wp_get_post_autosave($post->ID);

	if ( ! is_object($preview) )
		return $post;

	$preview = sanitize_post($preview);

	$post->post_content = $preview->post_content;
	$post->post_title = $preview->post_title;
	$post->post_excerpt = $preview->post_excerpt;

	return $post;
}

function _show_post_preview() {

	if ( isset($_GET['preview_id']) && isset($_GET['preview_nonce']) ) {
		$id = (int) $_GET['preview_id'];

		if ( false == wp_verify_nonce( $_GET['preview_nonce'], 'post_preview_' . $id ) )
			wp_die( __('You do not have permission to preview drafts.') );

		add_filter('the_preview', '_set_preview');
	}
}

/**
 * Returns the post's parent's post_ID
 *
 * @since 3.1.0
 *
 * @param int $post_id
 *
 * @return int|bool false on error
 */
function wp_get_post_parent_id( $post_ID ) {
	$post = get_post( $post_ID );
	if ( !$post || is_wp_error( $post ) )
		return false;
	return (int) $post->post_parent;
}

/**
 * Checks the given subset of the post hierarchy for hierarchy loops.
 * Prevents loops from forming and breaks those that it finds.
 *
 * Attached to the wp_insert_post_parent filter.
 *
 * @since 3.1.0
 * @uses wp_find_hierarchy_loop()
 *
 * @param int $post_parent ID of the parent for the post we're checking.
 * @param int $post_ID ID of the post we're checking.
 *
 * @return int The new post_parent for the post.
 */
function wp_check_post_hierarchy_for_loops( $post_parent, $post_ID ) {
	// Nothing fancy here - bail
	if ( !$post_parent )
		return 0;

	// New post can't cause a loop
	if ( empty( $post_ID ) )
		return $post_parent;

	// Can't be its own parent
	if ( $post_parent == $post_ID )
		return 0;

	// Now look for larger loops

	if ( !$loop = wp_find_hierarchy_loop( 'wp_get_post_parent_id', $post_ID, $post_parent ) )
		return $post_parent; // No loop

	// Setting $post_parent to the given value causes a loop
	if ( isset( $loop[$post_ID] ) )
		return 0;

	// There's a loop, but it doesn't contain $post_ID. Break the loop.
	foreach ( array_keys( $loop ) as $loop_member )
		wp_update_post( array( 'ID' => $loop_member, 'post_parent' => 0 ) );

	return $post_parent;
}

/**
 * Returns an array of post format slugs to their translated and pretty display versions
 *
 * @since 3.1.0
 *
 * @return array The array of translations
 */
function get_post_format_strings() {
	$strings = array(
		'standard' => _x( 'Standard', 'Post format' ), // Special case. any value that evals to false will be considered standard
		'aside'    => _x( 'Aside',    'Post format' ),
		'chat'     => _x( 'Chat',     'Post format' ),
		'gallery'  => _x( 'Gallery',  'Post format' ),
		'link'     => _x( 'Link',     'Post format' ),
		'image'    => _x( 'Image',    'Post format' ),
		'quote'    => _x( 'Quote',    'Post format' ),
		'status'   => _x( 'Status',   'Post format' ),
		'video'    => _x( 'Video',    'Post format' ),
		'audio'    => _x( 'Audio',    'Post format' ),
	);
	return $strings;
}

/**
 * Retrieves an array of post format slugs.
 *
 * @since 3.1.0
 *
 * @return array The array of post format slugs.
 */
function get_post_format_slugs() {
	$slugs = array_keys( get_post_format_strings() );
	return array_combine( $slugs, $slugs );
}

/**
 * Returns a pretty, translated version of a post format slug
 *
 * @since 3.1.0
 *
 * @param string $slug A post format slug
 * @return string The translated post format name
 */
function get_post_format_string( $slug ) {
	$strings = get_post_format_strings();
	if ( !$slug )
		return $strings['standard'];
	else
		return ( isset( $strings[$slug] ) ) ? $strings[$slug] : '';
}

/**
 * Sets a post thumbnail.
 *
 * @since 3.1.0
 *
 * @param int|object $post Post ID or object where thumbnail should be attached.
 * @param int $thumbnail_id Thumbnail to attach.
 * @return bool True on success, false on failure.
 */
function set_post_thumbnail( $post, $thumbnail_id ) {
	$post = get_post( $post );
	$thumbnail_id = absint( $thumbnail_id );
	if ( $post && $thumbnail_id && get_post( $thumbnail_id ) ) {
		$thumbnail_html = wp_get_attachment_image( $thumbnail_id, 'thumbnail' );
		if ( ! empty( $thumbnail_html ) ) {
			return update_post_meta( $post->ID, '_thumbnail_id', $thumbnail_id );
		}
	}
	return false;
}

/**
 * Removes a post thumbnail.
 *
 * @since 3.3.0
 *
 * @param int|object $post Post ID or object where thumbnail should be removed from.
 * @return bool True on success, false on failure.
 */
function delete_post_thumbnail( $post ) {
	$post = get_post( $post );
	if ( $post )
		return delete_post_meta( $post->ID, '_thumbnail_id' );
	return false;
}

/**
 * Returns a link to a post format index.
 *
 * @since 3.1.0
 *
 * @param string $format Post format
 * @return string Link
 */
function get_post_format_link( $format ) {
	$term = get_term_by('slug', 'post-format-' . $format, 'post_format' );
	if ( ! $term || is_wp_error( $term ) )
		return false;
	return get_term_link( $term );
}

/**
 * Deletes auto-drafts for new posts that are > 7 days old
 *
 * @since 3.4.0
 */
function wp_delete_auto_drafts() {
	global $wpdb;

	// Cleanup old auto-drafts more than 7 days old
	$old_posts = $wpdb->get_col( "SELECT ID FROM $wpdb->posts WHERE post_status = 'auto-draft' AND DATE_SUB( NOW(), INTERVAL 7 DAY ) > post_date" );
	foreach ( (array) $old_posts as $delete )
		wp_delete_post( $delete, true ); // Force delete
}

/**
 * Filters the request to allow for the format prefix.
 *
 * @access private
 * @since 3.1.0
 */
function _post_format_request( $qvs ) {
	if ( ! isset( $qvs['post_format'] ) )
		return $qvs;
	$slugs = get_post_format_slugs();
	if ( isset( $slugs[ $qvs['post_format'] ] ) )
		$qvs['post_format'] = 'post-format-' . $slugs[ $qvs['post_format'] ];
	$tax = get_taxonomy( 'post_format' );
	if ( ! is_admin() )
		$qvs['post_type'] = $tax->object_type;
	return $qvs;
}
add_filter( 'request', '_post_format_request' );

/**
 * Filters the post format term link to remove the format prefix.
 *
 * @access private
 * @since 3.1.0
 */
function _post_format_link( $link, $term, $taxonomy ) {
	global $wp_rewrite;
	if ( 'post_format' != $taxonomy )
		return $link;
	if ( $wp_rewrite->get_extra_permastruct( $taxonomy ) ) {
		return str_replace( "/{$term->slug}", '/' . str_replace( 'post-format-', '', $term->slug ), $link );
	} else {
		$link = remove_query_arg( 'post_format', $link );
		return add_query_arg( 'post_format', str_replace( 'post-format-', '', $term->slug ), $link );
	}
}
add_filter( 'term_link', '_post_format_link', 10, 3 );

/**
 * Remove the post format prefix from the name property of the term object created by get_term().
 *
 * @access private
 * @since 3.1.0
 */
function _post_format_get_term( $term ) {
	if ( isset( $term->slug ) ) {
		$term->name = get_post_format_string( str_replace( 'post-format-', '', $term->slug ) );
	}
	return $term;
}
add_filter( 'get_post_format', '_post_format_get_term' );

/**
 * Remove the post format prefix from the name property of the term objects created by get_terms().
 *
 * @access private
 * @since 3.1.0
 */
function _post_format_get_terms( $terms, $taxonomies, $args ) {
	if ( in_array( 'post_format', (array) $taxonomies ) ) {
		if ( isset( $args['fields'] ) && 'names' == $args['fields'] ) {
			foreach( $terms as $order => $name ) {
				$terms[$order] = get_post_format_string( str_replace( 'post-format-', '', $name ) );
			}
		} else {
			foreach ( (array) $terms as $order => $term ) {
				if ( isset( $term->taxonomy ) && 'post_format' == $term->taxonomy ) {
					$terms[$order]->name = get_post_format_string( str_replace( 'post-format-', '', $term->slug ) );
				}
			}
		}
	}
	return $terms;
}
add_filter( 'get_terms', '_post_format_get_terms', 10, 3 );

/**
 * Remove the post format prefix from the name property of the term objects created by wp_get_object_terms().
 *
 * @access private
 * @since 3.1.0
 */
function _post_format_wp_get_object_terms( $terms ) {
	foreach ( (array) $terms as $order => $term ) {
		if ( isset( $term->taxonomy ) && 'post_format' == $term->taxonomy ) {
			$terms[$order]->name = get_post_format_string( str_replace( 'post-format-', '', $term->slug ) );
		}
	}
	return $terms;
}
add_filter( 'wp_get_object_terms', '_post_format_wp_get_object_terms' );

/**
 * Update the custom taxonomies' term counts when a post's status is changed. For example, default posts term counts (for custom taxonomies) don't include private / draft posts.
 *
 * @access private
 * @param string $new_status
 * @param string $old_status
 * @param object $post
 * @since 3.3.0
 */
function _update_term_count_on_transition_post_status( $new_status, $old_status, $post ) {
	// Update counts for the post's terms.
	foreach ( (array) get_object_taxonomies( $post->post_type ) as $taxonomy ) {
		$tt_ids = wp_get_object_terms( $post->ID, $taxonomy, array( 'fields' => 'tt_ids' ) );
		wp_update_term_count( $tt_ids, $taxonomy );
	}
}

/**
 * Adds any posts from the given ids to the cache that do not already exist in cache
 *
 * @since 3.4.0
 *
 * @access private
 *
 * @param array $post_ids ID list
 * @param bool $update_term_cache Whether to update the term cache. Default is true.
 * @param bool $update_meta_cache Whether to update the meta cache. Default is true.
 */
function _prime_post_caches( $ids, $update_term_cache = true, $update_meta_cache = true ) {
	global $wpdb;

	$non_cached_ids = _get_non_cached_ids( $ids, 'posts' );
	if ( !empty( $non_cached_ids ) ) {
		$fresh_posts = $wpdb->get_results( sprintf( "SELECT $wpdb->posts.* FROM $wpdb->posts WHERE ID IN (%s)", join( ",", $non_cached_ids ) ) );

		update_post_caches( $fresh_posts, 'any', $update_term_cache, $update_meta_cache );
	}
}