Media: Add WP_Image_Editor_Imagick::set_imagick_time_limit() method.

This aims to avoid timeout in Imagick operations.

Previously, Imagick operations could silently error by timeout and produce unexpected results. The new `::set_imagick_time_limit()` method, now used in `::resize()` and `::crop()`, will better handle garbage collection in these cases as well as better align Imagick's timeout with PHP timeout, assuming it is set.

Props drzraf, audrasjb, costdev, antpb, SergeyBiryukov.
Fixes #52569.

git-svn-id: https://develop.svn.wordpress.org/trunk@55404 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-debug-data.php

@@ -581,6 +581,7 @@ public static function debug_data() {
 				'map'    => ( defined( 'imagick::RESOURCETYPE_MAP' ) ? size_format( $imagick->getResourceLimit( imagick::RESOURCETYPE_MAP ) ) : $not_available ),
 				'memory' => ( defined( 'imagick::RESOURCETYPE_MEMORY' ) ? size_format( $imagick->getResourceLimit( imagick::RESOURCETYPE_MEMORY ) ) : $not_available ),
 				'thread' => ( defined( 'imagick::RESOURCETYPE_THREAD' ) ? $imagick->getResourceLimit( imagick::RESOURCETYPE_THREAD ) : $not_available ),
+				'time'   => ( defined( 'imagick::RESOURCETYPE_TIME' ) ? $imagick->getResourceLimit( imagick::RESOURCETYPE_TIME ) : $not_available ),
 			);
 
 			$limits_debug = array(
@@ -590,6 +591,7 @@ public static function debug_data() {
 				'imagick::RESOURCETYPE_MAP'    => ( defined( 'imagick::RESOURCETYPE_MAP' ) ? size_format( $imagick->getResourceLimit( imagick::RESOURCETYPE_MAP ) ) : 'not available' ),
 				'imagick::RESOURCETYPE_MEMORY' => ( defined( 'imagick::RESOURCETYPE_MEMORY' ) ? size_format( $imagick->getResourceLimit( imagick::RESOURCETYPE_MEMORY ) ) : 'not available' ),
 				'imagick::RESOURCETYPE_THREAD' => ( defined( 'imagick::RESOURCETYPE_THREAD' ) ? $imagick->getResourceLimit( imagick::RESOURCETYPE_THREAD ) : 'not available' ),
+				'imagick::RESOURCETYPE_TIME'   => ( defined( 'imagick::RESOURCETYPE_TIME' ) ? $imagick->getResourceLimit( imagick::RESOURCETYPE_TIME ) : 'not available' ),
 			);
 
 			$info['wp-media']['fields']['imagick_limits'] = array(

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

@@ -253,6 +253,50 @@ protected function update_size( $width = null, $height = null ) {
 		return parent::update_size( $width, $height );
 	}
 
+	/**
+	 * Sets Imagick time limit.
+	 *
+	 * Depending on configuration, Imagick processing may take time.
+	 *
+	 * Multiple problems exist if PHP times out before ImageMagick completed:
+	 * 1. Temporary files aren't cleaned by ImageMagick garbage collection.
+	 * 2. No clear error is provided.
+	 * 3. The cause of such timeout can be hard to pinpoint.
+	 *
+	 * This function, which is expected to be run before heavy image routines, resolves
+	 * point 1 above by aligning Imagick's timeout with PHP's timeout, assuming it is set.
+	 *
+	 * Note:
+	 *  - Imagick resource exhaustion does not issue catchable exceptions (yet).
+	 *    See https://github.com/Imagick/imagick/issues/333.
+	 *  - The resource limit is not saved/restored. It applies to subsequent
+	 *    image operations within the time of the HTTP request.
+	 *
+	 * @since 6.2.0
+	 *
+	 * @return int|null The new limit on success, null on failure.
+	 */
+	public static function set_imagick_time_limit() {
+		if ( ! defined( 'Imagick::RESOURCETYPE_TIME' ) ) {
+			return null;
+		}
+
+		// Returns PHP_FLOAT_MAX if unset.
+		$imagick_timeout = Imagick::getResourceLimit( Imagick::RESOURCETYPE_TIME );
+
+		// Convert to an integer, keeping in mind that: 0 === (int) PHP_FLOAT_MAX.
+		$imagick_timeout = $imagick_timeout > PHP_INT_MAX ? PHP_INT_MAX : (int) $imagick_timeout;
+
+		$php_timeout = (int) ini_get( 'max_execution_time' );
+
+		if ( $php_timeout > 1 && $php_timeout < $imagick_timeout ) {
+			$limit = (float) 0.8 * $php_timeout;
+			Imagick::setResourceLimit( Imagick::RESOURCETYPE_TIME, $limit );
+
+			return $limit;
+		}
+	}
+
 	/**
 	 * Resizes current image.
 	 *
@@ -283,6 +327,8 @@ public function resize( $max_w, $max_h, $crop = false ) {
 			return $this->crop( $src_x, $src_y, $src_w, $src_h, $dst_w, $dst_h );
 		}
 
+		self::set_imagick_time_limit();
+
 		// Execute the resize.
 		$thumb_result = $this->thumbnail_image( $dst_w, $dst_h );
 		if ( is_wp_error( $thumb_result ) ) {
@@ -549,6 +595,8 @@ public function crop( $src_x, $src_y, $src_w, $src_h, $dst_w = null, $dst_h = nu
 			$src_h -= $src_y;
 		}
 
+		self::set_imagick_time_limit();
+
 		try {
 			$this->image->cropImage( $src_w, $src_h, $src_x, $src_y );
 			$this->image->setImagePage( $src_w, $src_h, 0, 0 );