Bootstrap: Enhance core's memory limit handling.

* Don't lower memory limit if the current limit is greater than `WP_MAX_MEMORY_LIMIT`.
* Set `WP_MEMORY_LIMIT` and `WP_MAX_MEMORY_LIMIT` to current limit if the `memory_limit` setting can't be changed at runtime.
* Use `wp_convert_hr_to_bytes()` when parsing the value of the `memory_limit` setting because it can be a shorthand or an integer value.
* Introduce `wp_raise_memory_limit( $context )` to raise the PHP memory limit for memory intensive processes. This DRYs up some logic and includes the existing `admin_memory_limit` and `image_memory_limit` filters. The function can also be used for custom contexts, the `{$context}_memory_limit` filter allows to customize the limit.
* Introduce `wp_is_ini_value_changeable( $setting )` to determine whether a PHP ini value is changeable at runtime.
* Remove a `function_exists( 'memory_get_usage' )` check. Since PHP 5.2.1 support for memory limit is always enabled.

Related commits: [38011-38013]

Props jrf, A5hleyRich, swissspidy, ocean90.
Fixes #32075.

git-svn-id: https://develop.svn.wordpress.org/trunk@38015 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/admin.php

@@ -138,21 +138,7 @@ else
 	require(ABSPATH . 'wp-admin/menu.php');
 
 if ( current_user_can( 'manage_options' ) ) {
-	/**
+	wp_raise_memory_limit( 'admin' );
-	 * Filters the maximum memory limit available for administration screens.
-	 *
-	 * This only applies to administrators, who may require more memory for tasks like updates.
-	 * Memory limits when processing images (uploaded or edited by users of any role) are
-	 * handled separately.
-	 *
-	 * The WP_MAX_MEMORY_LIMIT constant specifically defines the maximum memory limit available
-	 * when in the administration back end. The default is 256M, or 256 megabytes of memory.
-	 *
-	 * @since 3.0.0
-	 *
-	 * @param string 'WP_MAX_MEMORY_LIMIT' The maximum WordPress memory limit. Default 256M.
-	 */
-	@ini_set( 'memory_limit', apply_filters( 'admin_memory_limit', WP_MAX_MEMORY_LIMIT ) );
 }
 
 /**

src/wp-admin/includes/file.php

@@ -569,9 +569,8 @@ function unzip_file($file, $to) {
 	if ( ! $wp_filesystem || !is_object($wp_filesystem) )
 		return new WP_Error('fs_unavailable', __('Could not access filesystem.'));
 
-	// Unzip can use a lot of memory, but not this much hopefully
+	// Unzip can use a lot of memory, but not this much hopefully.
-	/** This filter is documented in wp-admin/admin.php */
+	wp_raise_memory_limit( 'admin' );
-	@ini_set( 'memory_limit', apply_filters( 'admin_memory_limit', WP_MAX_MEMORY_LIMIT ) );
 
 	$needed_dirs = array();
 	$to = trailingslashit($to);

src/wp-admin/includes/image-edit.php

@@ -585,8 +585,7 @@ function image_edit_apply_changes( $image, $changes ) {
 function stream_preview_image( $post_id ) {
 	$post = get_post( $post_id );
 
-	/** This filter is documented in wp-admin/admin.php */
+	wp_raise_memory_limit( 'admin' );
-	@ini_set( 'memory_limit', apply_filters( 'admin_memory_limit', WP_MAX_MEMORY_LIMIT ) );
 
 	$img = wp_get_image_editor( _load_image_to_edit_path( $post_id ) );
 

src/wp-includes/class-wp-image-editor-gd.php

@@ -96,18 +96,8 @@ class WP_Image_Editor_GD extends WP_Image_Editor {
 		if ( ! is_file( $this->file ) && ! preg_match( '|^https?://|', $this->file ) )
 			return new WP_Error( 'error_loading_image', __('File doesn’t exist?'), $this->file );
 
-		/**
-		 * Filters the memory limit allocated for image manipulation.
-		 *
-		 * @since 3.5.0
-		 *
-		 * @param int|string $limit Maximum memory limit to allocate for images. Default WP_MAX_MEMORY_LIMIT.
-		 *                          Accepts an integer (bytes), or a shorthand string notation, such as '256M'.
-		 */
-		$image_memory_limit = apply_filters( 'image_memory_limit', WP_MAX_MEMORY_LIMIT );
-
 		// Set artificially high because GD uses uncompressed images in memory.
-		@ini_set( 'memory_limit', $image_memory_limit );
+		wp_raise_memory_limit( 'image' );
 
 		$this->image = @imagecreatefromstring( file_get_contents( $this->file ) );
 

src/wp-includes/class-wp-image-editor-imagick.php

@@ -137,14 +137,11 @@ class WP_Image_Editor_Imagick extends WP_Image_Editor {
 		if ( ! is_file( $this->file ) && ! preg_match( '|^https?://|', $this->file ) )
 			return new WP_Error( 'error_loading_image', __('File doesn’t exist?'), $this->file );
 
-		/** This filter is documented in wp-includes/class-wp-image-editor-gd.php */
-		$image_memory_limit = apply_filters( 'image_memory_limit', WP_MAX_MEMORY_LIMIT );
-
 		/*
 		 * Even though Imagick uses less PHP memory than GD, set higher limit
 		 * for users that have low PHP.ini limits.
 		 */
-		@ini_set( 'memory_limit', $image_memory_limit );
+		wp_raise_memory_limit( 'image' );
 
 		try {
 			$this->image = new Imagick( $this->file );

src/wp-includes/default-constants.php

@@ -28,36 +28,39 @@ function wp_initial_constants() {
 	define( 'TB_IN_BYTES', 1024 * GB_IN_BYTES );
 	/**#@-*/
 
-	// set memory limits
+	$current_limit     = @ini_get( 'memory_limit' );
-	if ( !defined('WP_MEMORY_LIMIT') ) {
+	$current_limit_int = wp_convert_hr_to_bytes( $current_limit );
-		if ( is_multisite() ) {
+
-			define('WP_MEMORY_LIMIT', '64M');
+	// Define memory limits.
+	if ( ! defined( 'WP_MEMORY_LIMIT' ) ) {
+		if ( false === wp_is_ini_value_changeable( 'memory_limit' ) ) {
+			define( 'WP_MEMORY_LIMIT', $current_limit );
+		} elseif ( is_multisite() ) {
+			define( 'WP_MEMORY_LIMIT', '64M' );
 		} else {
-			define('WP_MEMORY_LIMIT', '40M');
+			define( 'WP_MEMORY_LIMIT', '40M' );
 		}
 	}
 
 	if ( ! defined( 'WP_MAX_MEMORY_LIMIT' ) ) {
-		define( 'WP_MAX_MEMORY_LIMIT', '256M' );
+		if ( false === wp_is_ini_value_changeable( 'memory_limit' ) ) {
+			define( 'WP_MAX_MEMORY_LIMIT', $current_limit );
+		} elseif ( -1 === $current_limit_int || $current_limit_int > 268435456 /* = 256M */ ) {
+			define( 'WP_MAX_MEMORY_LIMIT', $current_limit );
+		} else {
+			define( 'WP_MAX_MEMORY_LIMIT', '256M' );
+		}
+	}
+
+	// Set memory limits.
+	$wp_limit_int = wp_convert_hr_to_bytes( WP_MEMORY_LIMIT );
+	if ( -1 !== $current_limit_int && ( -1 === $wp_limit_int || $wp_limit_int > $current_limit_int ) ) {
+		@ini_set( 'memory_limit', WP_MEMORY_LIMIT );
 	}
 
 	if ( ! isset($blog_id) )
 		$blog_id = 1;
 
-	// set memory limits.
-	if ( function_exists( 'memory_get_usage' ) ) {
-		$current_limit = @ini_get( 'memory_limit' );
-		$current_limit_int = intval( $current_limit );
-		if ( false !== strpos( $current_limit, 'G' ) )
-			$current_limit_int *= 1024;
-		$wp_limit_int = intval( WP_MEMORY_LIMIT );
-		if ( false !== strpos( WP_MEMORY_LIMIT, 'G' ) )
-			$wp_limit_int *= 1024;
-
-		if ( -1 != $current_limit && ( -1 == WP_MEMORY_LIMIT || $current_limit_int < $wp_limit_int ) )
-			@ini_set( 'memory_limit', WP_MEMORY_LIMIT );
-	}
-
 	if ( !defined('WP_CONTENT_DIR') )
 		define( 'WP_CONTENT_DIR', ABSPATH . 'wp-content' ); // no trailing slash, full paths only - WP_CONTENT_URL is defined further down
 

src/wp-includes/deprecated.php

@@ -3175,11 +3175,8 @@ function wp_load_image( $file ) {
 	if ( ! function_exists('imagecreatefromstring') )
 		return __('The GD image library is not installed.');
 
-	/** This filter is documented in wp-includes/class-wp-image-editor-gd.php */
-	$image_memory_limit = apply_filters( 'image_memory_limit', WP_MAX_MEMORY_LIMIT );
-
 	// Set artificially high because GD uses uncompressed images in memory.
-	@ini_set( 'memory_limit', $image_memory_limit );
+	wp_raise_memory_limit( 'image' );
 
 	$image = imagecreatefromstring( file_get_contents( $file ) );
 

src/wp-includes/functions.php

@@ -5379,3 +5379,112 @@ function wp_object_type_exists( $object_type ) {
 
 	return false;
 }
+
+/**
+ * Attempts to raise the PHP memory limit for memory intensive processes.
+ *
+ * Only allows raising the existing limit and prevents lowering it.
+ *
+ * @since 4.6.0
+ *
+ * @param string $context  Context in which the function is called.
+ *                         Either 'admin', 'image' or an arbitrary other context.
+ *                         Defaults to 'admin'.
+ *                         If an arbitrary context is passed, the similarly arbitrary
+ *                         "{$context}_memory_limit" filter will be invoked.
+ * @return bool|int|string The limit that was set or false on failure.
+ */
+function wp_raise_memory_limit( $context = 'admin' ) {
+	// Exit early if the limit cannot be changed.
+	if ( false === wp_is_ini_value_changeable( 'memory_limit' ) ) {
+		return false;
+	}
+
+	$current_limit     = @ini_get( 'memory_limit' );
+	$current_limit_int = wp_convert_hr_to_bytes( $current_limit );
+
+	if ( -1 === $current_limit_int ) {
+		return false;
+	}
+
+	$wp_max_limit     = WP_MAX_MEMORY_LIMIT;
+	$wp_max_limit_int = wp_convert_hr_to_bytes( $wp_max_limit );
+	$filtered_limit   = $wp_max_limit;
+
+	switch ( $context ) {
+		case 'admin':
+			/**
+			 * Filters the maximum memory limit available for administration screens.
+			 *
+			 * This only applies to administrators, who may require more memory for tasks like updates.
+			 * Memory limits when processing images (uploaded or edited by users of any role) are
+			 * handled separately.
+			 *
+			 * The WP_MAX_MEMORY_LIMIT constant specifically defines the maximum memory limit available
+			 * when in the administration back end. The default is 256M (256 megabytes
+			 * of memory) or the original `memory_limit` php.ini value if this is higher.
+			 *
+			 * @since 3.0.0
+			 * @since 4.6.0 The default takes the original `memory_limit` into account.
+			 *
+			 * @param int|string $filtered_limit The maximum WordPress memory limit.
+			 *                                   Accepts an integer (bytes), or a shorthand string
+			 *                                   notation, such as '256M'.
+			 */
+			$filtered_limit = apply_filters( 'admin_memory_limit', $filtered_limit );
+			break;
+
+		case 'image':
+			/**
+			 * Filters the memory limit allocated for image manipulation.
+			 *
+			 * @since 3.5.0
+			 * @since 4.6.0 The default takes the original `memory_limit` into account.
+			 *
+			 * @param int|string $filtered_limit Maximum memory limit to allocate for images.
+			 *                                   Default WP_MAX_MEMORY_LIMIT or the original
+			 *                                   php.ini memory_limit, whichever is higher.
+			 *                                   Accepts an integer (bytes), or a shorthand string
+			 *                                   notation, such as '256M'.
+			 */
+			$filtered_limit = apply_filters( 'image_memory_limit', $filtered_limit );
+			break;
+
+		default:
+			/**
+			 * Filters the memory limit allocated for arbitrary contexts.
+			 *
+			 * The dynamic portion of the hook name, `$context`, refers to an arbitrary
+			 * context passed on calling the function. This allows for plugins to define
+			 * their own contexts for raising the memory limit.
+			 *
+			 * @since 4.6.0
+			 *
+			 * @param int|string $filtered_limit Maximum memory limit to allocate for images.
+			 *                                   Default 256M or the original php.ini memory_limit,
+			 *                                   whichever is higher.
+			 *                                   Accepts an integer (bytes), or a shorthand string
+			 *                                   notation, such as '256M'.
+			 */
+			$filtered_limit = apply_filters( "{$context}_memory_limit", $filtered_limit );
+			break;
+	}
+
+	$filtered_limit_int = wp_convert_hr_to_bytes( $filtered_limit );
+
+	if ( -1 === $filtered_limit_int || ( $filtered_limit_int > $wp_max_limit_int && $filtered_limit_int > $current_limit_int ) ) {
+		if ( false !== @ini_set( 'memory_limit', $filtered_limit ) ) {
+			return $filtered_limit;
+		} else {
+			return false;
+		}
+	} elseif ( -1 === $wp_max_limit_int || $wp_max_limit_int > $current_limit_int ) {
+		if ( false !== @ini_set( 'memory_limit', $wp_max_limit ) ) {
+			return $wp_max_limit;
+		} else {
+			return false;
+		}
+	}
+
+	return false;
+}

src/wp-includes/load.php

@@ -1002,3 +1002,27 @@ function wp_convert_hr_to_bytes( $value ) {
 	// Deal with large (float) values which run into the maximum integer size.
 	return min( $bytes, PHP_INT_MAX );
 }
+
+/**
+ * Determines whether a PHP ini value is changeable at runtime.
+ *
+ * @since 4.6.0
+ *
+ * @link http://php.net/manual/en/function.ini-get-all.php
+ *
+ * @param string $setting The name of the ini setting to check.
+ * @return bool True if the value is changeable at runtime. False otherwise.
+ */
+function wp_is_ini_value_changeable( $setting ) {
+	static $ini_all;
+
+	if ( ! isset( $ini_all ) ) {
+		$ini_all = ini_get_all();
+	}
+
+	if ( isset( $ini_all[ $setting ]['access'] ) && ( INI_ALL === $ini_all[ $setting ]['access'] || INI_USER === $ini_all[ $setting ]['access'] ) ) {
+		return true;
+	}
+
+	return false;
+}

tests/phpunit/tests/functions.php

@@ -478,12 +478,12 @@ class Tests_Functions extends WP_UnitTestCase {
 				'Mozilla/5.0 (iPad; CPU OS 6_0 like Mac OS X) AppleWebKit/536.26 (KHTML, like Gecko) Version/6.0 Mobile/10A5376e Safari/8536.25',
 				true,
 			),
-			// Android 2.2, Android Webkit Browser 
+			// Android 2.2, Android Webkit Browser
 			array(
 				'Mozilla/5.0 (Android 2.2; Windows; U; Windows NT 6.1; en-US) AppleWebKit/533.19.4 (KHTML, like Gecko) Version/5.0.3 Safari/533.19.4',
 				true,
 			),
-			// BlackBerry 9900, BlackBerry browser 
+			// BlackBerry 9900, BlackBerry browser
 			array(
 				'Mozilla/5.0 (BlackBerry; U; BlackBerry 9900; en) AppleWebKit/534.11+ (KHTML, like Gecko) Version/7.1.0.346 Mobile Safari/534.11+',
 				true,
@@ -865,4 +865,18 @@ class Tests_Functions extends WP_UnitTestCase {
 
 		$this->assertNull( wp_ext2type( 'unknown_format' ) );
 	}
+
+	/**
+	 * Tests raising the memory limit.
+	 *
+	 * Unfortunately as the default for 'WP_MAX_MEMORY_LIMIT' in the
+	 * test suite is -1, we can not test the memory limit negotiations.
+	 *
+	 * @ticket 32075
+	 */
+	function test_wp_raise_memory_limit() {
+		ini_set( 'memory_limit', '40M' );
+		$this->assertSame( -1, wp_raise_memory_limit() );
+		$this->assertEquals( '-1', ini_get( 'memory_limit' ) );
+	}
 }

tests/phpunit/tests/load/isIniValueChangeable.php

@@ -0,0 +1,48 @@
+<?php
+
+/**
+ * Tests for wp_is_ini_value_changeable().
+ *
+ * @group load.php
+ */
+class Tests_Functions_Is_Ini_Value_Changeable extends WP_UnitTestCase {
+
+	/**
+	 * Tests the determining of the changeability of a PHP ini value.
+	 *
+	 * @ticket 32075
+	 *
+	 * @dataProvider data_wp_is_ini_value_changeable
+	 *
+	 * @param string $setting  The setting passed to wp_is_ini_value_changeable().
+	 * @param bool   $expected The expected output of wp_convert_hr_to_bytes().
+	 */
+	function test_wp_is_ini_value_changeable( $setting, $expected ) {
+		$this->assertSame( $expected, wp_is_ini_value_changeable( $setting ) );
+	}
+
+	/**
+	 * Data provider for test_wp_is_ini_value_changeable().
+	 *
+	 * @return array {
+	 *     @type array {
+	 *         @type string $setting  The setting passed to wp_is_ini_value_changeable().
+	 *         @type bool   $expected The expected output of wp_convert_hr_to_bytes().
+	 *     }
+	 * }
+	 */
+	function data_wp_is_ini_value_changeable() {
+		$array = array(
+			array( 'memory_limit', true ), // PHP_INI_ALL.
+			array( 'log_errors', true ), // PHP_INI_ALL.
+			array( 'upload_max_filesize', false ), // PHP_INI_PERDIR.
+			array( 'upload_tmp_dir', false ), // PHP_INI_SYSTEM.
+		);
+
+		if ( extension_loaded( 'Tidy' ) && version_compare( PHP_VERSION, '7.0.0', '>' ) ) {
+			$array[] = array( 'tidy.clean_output', true ); // PHP_INI_USER.
+		}
+
+		return $array;
+	}
+}