WordPress/wp-admin/includes/theme.php

<?php
/**
 * WordPress Theme Administration API
 *
 * @package WordPress
 * @subpackage Administration
 */

/**
 * Remove a theme
 *
 * @since 2.8.0
 *
 * @param string $template Template directory of the theme to delete
 * @param string $redirect Redirect to page when complete.
 * @return mixed
 */
function delete_theme($template, $redirect = '') {
	global $wp_filesystem;

	if ( empty($template) )
		return false;

	ob_start();
	if ( empty( $redirect ) )
		$redirect = wp_nonce_url('themes.php?action=delete&template=' . $template, 'delete-theme_' . $template);
	if ( false === ($credentials = request_filesystem_credentials($redirect)) ) {
		$data = ob_get_contents();
		ob_end_clean();
		if ( ! empty($data) ){
			include_once( ABSPATH . 'wp-admin/admin-header.php');
			echo $data;
			include( ABSPATH . 'wp-admin/admin-footer.php');
			exit;
		}
		return;
	}

	if ( ! WP_Filesystem($credentials) ) {
		request_filesystem_credentials($url, '', true); // Failed to connect, Error and request again
		$data = ob_get_contents();
		ob_end_clean();
		if ( ! empty($data) ) {
			include_once( ABSPATH . 'wp-admin/admin-header.php');
			echo $data;
			include( ABSPATH . 'wp-admin/admin-footer.php');
			exit;
		}
		return;
	}

	if ( ! is_object($wp_filesystem) )
		return new WP_Error('fs_unavailable', __('Could not access filesystem.'));

	if ( is_wp_error($wp_filesystem->errors) && $wp_filesystem->errors->get_error_code() )
		return new WP_Error('fs_error', __('Filesystem error.'), $wp_filesystem->errors);

	//Get the base plugin folder
	$themes_dir = $wp_filesystem->wp_themes_dir();
	if ( empty($themes_dir) )
		return new WP_Error('fs_no_themes_dir', __('Unable to locate WordPress theme directory.'));

	$themes_dir = trailingslashit( $themes_dir );
	$theme_dir = trailingslashit($themes_dir . $template);
	$deleted = $wp_filesystem->delete($theme_dir, true);

	if ( ! $deleted )
		return new WP_Error('could_not_remove_theme', sprintf(__('Could not fully remove the theme %s.'), $template) );

	// Force refresh of theme update information
	delete_site_transient('update_themes');

	return true;
}

/**
 * Get the Page Templates available in this theme
 *
 * @since 1.5.0
 *
 * @return array Key is the template name, value is the filename of the template
 */
function get_page_templates() {
	return array_flip( wp_get_theme()->get_page_templates() );
}

/**
 * Tidies a filename for url display by the theme editor.
 *
 * @since 2.9.0
 * @access private
 *
 * @param string $fullpath Full path to the theme file
 * @param string $containingfolder Path of the theme parent folder
 * @return string
 */
function _get_template_edit_filename($fullpath, $containingfolder) {
	return str_replace(dirname(dirname( $containingfolder )) , '', $fullpath);
}

/**
 * Check if there is an update for a theme available.
 *
 * Will display link, if there is an update available.
 *
 * @since 2.7.0
 *
 * @param object $theme Theme data object.
 * @return bool False if no valid info was passed.
 */
function theme_update_available( $theme ) {
	static $themes_update;

	if ( !current_user_can('update_themes' ) )
		return;

	if ( !isset($themes_update) )
		$themes_update = get_site_transient('update_themes');

	if ( ! is_a( $theme, 'WP_Theme' ) )
		return;

	$stylesheet = $theme->get_stylesheet();

	if ( isset($themes_update->response[ $stylesheet ]) ) {
		$update = $themes_update->response[ $stylesheet ];
		$theme_name = $theme->get('Name');
		$details_url = add_query_arg(array('TB_iframe' => 'true', 'width' => 1024, 'height' => 800), $update['url']); //Theme browser inside WP? replace this, Also, theme preview JS will override this on the available list.
		$update_url = wp_nonce_url('update.php?action=upgrade-theme&amp;theme=' . urlencode($stylesheet), 'upgrade-theme_' . $stylesheet);
		$update_onclick = 'onclick="if ( confirm(\'' . esc_js( __("Updating this theme will lose any customizations you have made. 'Cancel' to stop, 'OK' to update.") ) . '\') ) {return true;}return false;"';

		if ( !is_multisite() ) {
			if ( ! current_user_can('update_themes') )
				printf( '<p><strong>' . __('There is a new version of %1$s available. <a href="%2$s" class="thickbox" title="%1$s">View version %3$s details</a>.') . '</strong></p>', $theme_name, $details_url, $update['new_version']);
			else if ( empty($update['package']) )
				printf( '<p><strong>' . __('There is a new version of %1$s available. <a href="%2$s" class="thickbox" title="%1$s">View version %3$s details</a>. <em>Automatic update is unavailable for this theme.</em>') . '</strong></p>', $theme_name, $details_url, $update['new_version']);
			else
				printf( '<p><strong>' . __('There is a new version of %1$s available. <a href="%2$s" class="thickbox" title="%1$s">View version %3$s details</a> or <a href="%4$s" %5$s>update now</a>.') . '</strong></p>', $theme_name, $details_url, $update['new_version'], $update_url, $update_onclick );
		}
	}
}

/**
 * Retrieve list of WordPress theme features (aka theme tags)
 *
 * @since 3.1.0
 *
 * @param bool $api Optional. Whether try to fetch tags from the WP.org API. Defaults to true.
 * @return array Array of features keyed by category with translations keyed by slug.
 */
function get_theme_feature_list( $api = true ) {
	// Hard-coded list is used if api not accessible.
	$features = array(
			__('Colors') => array(
				'black'   => __( 'Black' ),
				'blue'    => __( 'Blue' ),
				'brown'   => __( 'Brown' ),
				'gray'    => __( 'Gray' ),
				'green'   => __( 'Green' ),
				'orange'  => __( 'Orange' ),
				'pink'    => __( 'Pink' ),
				'purple'  => __( 'Purple' ),
				'red'     => __( 'Red' ),
				'silver'  => __( 'Silver' ),
				'tan'     => __( 'Tan' ),
				'white'   => __( 'White' ),
				'yellow'  => __( 'Yellow' ),
				'dark'    => __( 'Dark' ),
				'light'   => __( 'Light' ),
			),

		__('Columns') => array(
			'one-column'    => __( 'One Column' ),
			'two-columns'   => __( 'Two Columns' ),
			'three-columns' => __( 'Three Columns' ),
			'four-columns'  => __( 'Four Columns' ),
			'left-sidebar'  => __( 'Left Sidebar' ),
			'right-sidebar' => __( 'Right Sidebar' ),
		),

		__('Width') => array(
			'fixed-width'    => __( 'Fixed Width' ),
			'flexible-width' => __( 'Flexible Width' ),
		),

		__( 'Features' ) => array(
			'blavatar'              => __( 'Blavatar' ),
			'buddypress'            => __( 'BuddyPress' ),
			'custom-background'     => __( 'Custom Background' ),
			'custom-colors'         => __( 'Custom Colors' ),
			'custom-header'         => __( 'Custom Header' ),
			'custom-menu'           => __( 'Custom Menu' ),
			'editor-style'          => __( 'Editor Style' ),
			'featured-image-header' => __( 'Featured Image Header' ),
			'featured-images'       => __( 'Featured Images' ),
			'front-page-post-form'  => __( 'Front Page Posting' ),
			'full-width-template'   => __( 'Full Width Template' ),
			'microformats'          => __( 'Microformats' ),
			'post-formats'          => __( 'Post Formats' ),
			'rtl-language-support'  => __( 'RTL Language Support' ),
			'sticky-post'           => __( 'Sticky Post' ),
			'theme-options'         => __( 'Theme Options' ),
			'threaded-comments'     => __( 'Threaded Comments' ),
			'translation-ready'     => __( 'Translation Ready' ),
		),

		__( 'Subject' )  => array(
			'holiday'       => __( 'Holiday' ),
			'photoblogging' => __( 'Photoblogging' ),
			'seasonal'      => __( 'Seasonal' ),
		)
	);

	if ( ! $api || ! current_user_can( 'install_themes' ) )
		return $features;

	if ( !$feature_list = get_site_transient( 'wporg_theme_feature_list' ) )
		set_site_transient( 'wporg_theme_feature_list', array( ), 10800);

	if ( !$feature_list ) {
		$feature_list = themes_api( 'feature_list', array( ) );
		if ( is_wp_error( $feature_list ) )
			return $features;
	}

	if ( !$feature_list )
		return $features;

	set_site_transient( 'wporg_theme_feature_list', $feature_list, 10800 );

	$category_translations = array( 'Colors' => __('Colors'), 'Columns' => __('Columns'), 'Width' => __('Width'),
								   'Features' => __('Features'), 'Subject' => __('Subject') );

	// Loop over the wporg canonical list and apply translations
	$wporg_features = array();
	foreach ( (array) $feature_list as $feature_category => $feature_items ) {
		if ( isset($category_translations[$feature_category]) )
			$feature_category = $category_translations[$feature_category];
		$wporg_features[$feature_category] = array();

		foreach ( $feature_items as $feature ) {
			if ( isset($features[$feature_category][$feature]) )
				$wporg_features[$feature_category][$feature] = $features[$feature_category][$feature];
			else
				$wporg_features[$feature_category][$feature] = $feature;
		}
	}

	return $wporg_features;
}

/**
 * Retrieve theme installer pages from WordPress Themes API.
 *
 * It is possible for a theme to override the Themes API result with three
 * filters. Assume this is for themes, which can extend on the Theme Info to
 * offer more choices. This is very powerful and must be used with care, when
 * overridding the filters.
 *
 * The first filter, 'themes_api_args', is for the args and gives the action as
 * the second parameter. The hook for 'themes_api_args' must ensure that an
 * object is returned.
 *
 * The second filter, 'themes_api', is the result that would be returned.
 *
 * @since 2.8.0
 *
 * @param string $action
 * @param array|object $args Optional. Arguments to serialize for the Theme Info API.
 * @return mixed
 */
function themes_api($action, $args = null) {

	if ( is_array($args) )
		$args = (object)$args;

	if ( !isset($args->per_page) )
		$args->per_page = 24;

	$args = apply_filters('themes_api_args', $args, $action); //NOTE: Ensure that an object is returned via this filter.
	$res = apply_filters('themes_api', false, $action, $args); //NOTE: Allows a theme to completely override the builtin WordPress.org API.

	if ( ! $res ) {
		$request = wp_remote_post('http://api.wordpress.org/themes/info/1.0/', array( 'body' => array('action' => $action, 'request' => serialize($args))) );
		if ( is_wp_error($request) ) {
			$res = new WP_Error('themes_api_failed', __('An Unexpected HTTP Error occurred during the API request.'), $request->get_error_message() );
		} else {
			$res = maybe_unserialize( wp_remote_retrieve_body( $request ) );
			if ( ! is_object( $res ) && ! is_array( $res ) )
				$res = new WP_Error('themes_api_failed', __('An unknown error occurred during the API request.'), wp_remote_retrieve_body( $request ) );
		}
	}

	return apply_filters('themes_api_result', $res, $action, $args);
}