Replace `array_shift()` with `reset()` where appropriate for performance.

Props SergeyBiryukov.
Fixes #31259.

Built from https://develop.svn.wordpress.org/trunk@31829


git-svn-id: http://core.svn.wordpress.org/trunk@31811 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/ajax-actions.php

@@ -1091,7 +1091,7 @@ function wp_ajax_add_menu_item() {
 			}
 
 			$_menu_items = array_map( 'wp_setup_nav_menu_item', array( $_object ) );
-			$_menu_item = array_shift( $_menu_items );
+			$_menu_item = reset( $_menu_items );
 
 			// Restore the missing menu item properties
 			$menu_item_data['menu-item-description'] = $_menu_item->description;
@@ -1793,7 +1793,7 @@ function wp_ajax_save_widget() {
 		if ( !$multi_number )
 			wp_die( $error );
 
-		$_POST['widget-' . $id_base] = array( $multi_number => array_shift($settings) );
+		$_POST[ 'widget-' . $id_base ] = array( $multi_number => reset( $settings ) );
 		$widget_id = $id_base . '-' . $multi_number;
 		$sidebar[] = $widget_id;
 	}

wp-admin/includes/class-wp-upgrader.php

@@ -1904,7 +1904,7 @@ class Language_Pack_Upgrader extends WP_Upgrader {
 				break;
 			case 'plugin':
 				$plugin_data = get_plugins( '/' . $update->slug );
-				$plugin_data = array_shift( $plugin_data );
+				$plugin_data = reset( $plugin_data );
 				if ( $plugin_data )
 					return $plugin_data['Name'];
 				break;

wp-admin/includes/media.php

@@ -621,8 +621,8 @@ function media_upload_form_handler() {
 	$errors = null;
 
 	if ( isset($_POST['send']) ) {
-		$keys = array_keys($_POST['send']);
-		$send_id = (int) array_shift($keys);
+		$keys = array_keys( $_POST['send'] );
+		$send_id = (int) reset( $keys );
 	}
 
 	if ( !empty($_POST['attachments']) ) foreach ( $_POST['attachments'] as $attachment_id => $attachment ) {
@@ -1357,7 +1357,7 @@ function get_media_item( $attachment_id, $args = null ) {
 
 	$post_mime_types = get_post_mime_types();
 	$keys = array_keys( wp_match_mime_types( array_keys( $post_mime_types ), $post->post_mime_type ) );
-	$type = array_shift( $keys );
+	$type = reset( $keys );
 	$type_html = "<input type='hidden' id='type-of-$attachment_id' value='" . esc_attr( $type ) . "' />";
 
 	$form_fields = get_attachment_fields_to_edit( $post, $r['errors'] );

wp-admin/includes/menu.php

@@ -94,7 +94,7 @@ foreach ( $menu as $id => $data ) {
 	if ( empty($submenu[$data[2]]) )
 		continue;
 	$subs = $submenu[$data[2]];
-	$first_sub = array_shift($subs);
+	$first_sub = reset( $subs );
 	$old_parent = $data[2];
 	$new_parent = $first_sub[2];
 	/*
@@ -163,7 +163,7 @@ foreach ( $menu as $id => $data ) {
 	 */
 	if ( ! empty( $submenu[$data[2]] ) && 1 == count ( $submenu[$data[2]] ) ) {
 		$subs = $submenu[$data[2]];
-		$first_sub = array_shift($subs);
+		$first_sub = reset( $subs );
 		if ( $data[2] == $first_sub[2] )
 			unset( $submenu[$data[2]] );
 	}

wp-admin/includes/ms.php

@@ -804,11 +804,11 @@ function choose_primary_blog() {
 			</select>
 			<?php
 			if ( !$found ) {
-				$blog = array_shift( $all_blogs );
+				$blog = reset( $all_blogs );
 				update_user_meta( get_current_user_id(), 'primary_blog', $blog->userblog_id );
 			}
 		} elseif ( count( $all_blogs ) == 1 ) {
-			$blog = array_shift( $all_blogs );
+			$blog = reset( $all_blogs );
 			echo $blog->domain;
 			if ( $primary_blog != $blog->userblog_id ) // Set the primary blog again if it's out of sync with blog list.
 				update_user_meta( get_current_user_id(), 'primary_blog', $blog->userblog_id );

wp-admin/includes/plugin-install.php

@@ -304,7 +304,7 @@ function install_plugin_install_status($api, $loop = false) {
 					$url = wp_nonce_url(self_admin_url('update.php?action=install-plugin&plugin=' . $api->slug), 'install-plugin_' . $api->slug);
 			} else {
 				$key = array_keys( $installed_plugin );
-				$key = array_shift( $key ); //Use the first plugin regardless of the name, Could have issues for multiple-plugins in one directory if they share different version numbers
+				$key = reset( $key ); //Use the first plugin regardless of the name, Could have issues for multiple-plugins in one directory if they share different version numbers
 				$update_file = $api->slug . '/' . $key;
 				if ( version_compare($api->version, $installed_plugin[ $key ]['Version'], '=') ){
 					$status = 'latest_installed';
@@ -391,7 +391,7 @@ function install_plugin_information() {
 	$section = isset( $_REQUEST['section'] ) ? wp_unslash( $_REQUEST['section'] ) : 'description'; // Default to the Description tab, Do not translate, API returns English.
 	if ( empty( $section ) || ! isset( $api->sections[ $section ] ) ) {
 		$section_titles = array_keys( (array) $api->sections );
-		$section = array_shift( $section_titles );
+		$section = reset( $section_titles );
 	}
 
 	iframe_header( __( 'Plugin Install' ) );

wp-admin/user-edit.php

@@ -315,7 +315,7 @@ do_action( 'personal_options', $profileuser );
 <?php
 // Compare user role against currently editable roles
 $user_roles = array_intersect( array_values( $profileuser->roles ), array_keys( get_editable_roles() ) );
-$user_role  = array_shift( $user_roles );
+$user_role  = reset( $user_roles );
 
 // print the full list of roles with the primary one selected.
 wp_dropdown_roles($user_role);

wp-admin/widgets.php

@@ -189,7 +189,7 @@ if ( isset($_GET['editwidget']) && $_GET['editwidget'] ) {
 	if ( isset($_GET['addnew']) ) {
 		// Default to the first sidebar
 		$keys = array_keys( $wp_registered_sidebars );
-		$sidebar = array_shift( $keys );
+		$sidebar = reset( $keys );
 
 		if ( isset($_GET['base']) && isset($_GET['num']) ) { // multi-widget
 			// Copy minimal info from an existing instance of this widget to a new instance

wp-includes/pomo/streams.php

@@ -40,7 +40,7 @@ class POMO_Reader {
 			return false;
 		$endian_letter = ('big' == $this->endian)? 'N' : 'V';
 		$int = unpack($endian_letter, $bytes);
-		return array_shift($int);
+		return reset( $int );
 	}
 
 	/**

wp-includes/post-formats.php

@@ -26,7 +26,7 @@ function get_post_format( $post = null ) {
 	if ( empty( $_format ) )
 		return false;
 
-	$format = array_shift( $_format );
+	$format = reset( $_format );
 
 	return str_replace('post-format-', '', $format->slug );
 }

wp-includes/post.php

@@ -4599,7 +4599,7 @@ function get_pages( $args = array() ) {
 	}
 
 	if ( 1 == count( $post_status ) ) {
-		$where_post_type = $wpdb->prepare( "post_type = %s AND post_status = %s", $r['post_type'], array_shift( $post_status ) );
+		$where_post_type = $wpdb->prepare( "post_type = %s AND post_status = %s", $r['post_type'], reset( $post_status ) );
 	} else {
 		$post_status = implode( "', '", $post_status );
 		$where_post_type = $wpdb->prepare( "post_type = %s AND post_status IN ('$post_status')", $r['post_type'] );

wp-includes/query.php

@@ -4673,7 +4673,7 @@ function wp_old_slug_redirect() {
 		if ( is_array( $post_type ) ) {
 			if ( count( $post_type ) > 1 )
 				return;
-			$post_type = array_shift( $post_type );
+			$post_type = reset( $post_type );
 		}
 
 		// Do not attempt redirect for hierarchical post types

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.2-beta1-31828';
+$wp_version = '4.2-beta1-31829';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.