wp_get_loading_optimization_attributes( string $tag_name, array $attr, string $context ): array

Source

		}

		// If the editor for HEICs is Imagick, use it to get the image size.
		if ( $editor instanceof WP_Image_Editor_Imagick ) {
			$size = $editor->get_size();
			return array(
				$size['width'],
				$size['height'],
				IMAGETYPE_HEIC,
				sprintf(
					'width="%d" height="%d"',
					$size['width'],
					$size['height']
				),
				'mime' => 'image/heic',
			);
		}
	}

	// The image could not be parsed.
	return false;
}

/**
 * Extracts meta information about an AVIF file: width, height, bit depth, and number of channels.
 *
 * @since 6.5.0
 *
 * @param string $filename Path to an AVIF file.
 * @return array {
 *     An array of AVIF image information.
 *
 *     @type int|false $width        Image width on success, false on failure.
 *     @type int|false $height       Image height on success, false on failure.
 *     @type int|false $bit_depth    Image bit depth on success, false on failure.
 *     @type int|false $num_channels Image number of channels on success, false on failure.
 * }
 */
function wp_get_avif_info( $filename ) {
	$results = array(
		'width'        => false,
		'height'       => false,
		'bit_depth'    => false,
		'num_channels' => false,
	);

	if ( 'image/avif' !== wp_get_image_mime( $filename ) ) {
		return $results;
	}

	// Parse the file using libavifinfo's PHP implementation.
	require_once ABSPATH . WPINC . '/class-avif-info.php';

	$handle = fopen( $filename, 'rb' );
	if ( $handle ) {
		$parser  = new Avifinfo\Parser( $handle );
		$success = $parser->parse_ftyp() && $parser->parse_file();
		fclose( $handle );
		if ( $success ) {
			$results = $parser->features->primary_item_features;
		}
	}
	return $results;
}

/**
 * Extracts meta information about a WebP file: width, height, and type.
 *
 * @since 5.8.0
 *
 * @param string $filename Path to a WebP file.
 * @return array {
 *     An array of WebP image information.
 *
 *     @type int|false    $width  Image width on success, false on failure.
 *     @type int|false    $height Image height on success, false on failure.
 *     @type string|false $type   The WebP type: one of 'lossy', 'lossless' or 'animated-alpha'.
 *                                False on failure.
 * }
 */
function wp_get_webp_info( $filename ) {
	$width  = false;
	$height = false;
	$type   = false;

	if ( 'image/webp' !== wp_get_image_mime( $filename ) ) {
		return compact( 'width', 'height', 'type' );
	}

	$magic = file_get_contents( $filename, false, null, 0, 40 );

	if ( false === $magic ) {
		return compact( 'width', 'height', 'type' );
	}

	// Make sure we got enough bytes.
	if ( strlen( $magic ) < 40 ) {
		return compact( 'width', 'height', 'type' );
	}

	/*
	 * The headers are a little different for each of the three formats.
	 * Header values based on WebP docs, see https://developers.google.com/speed/webp/docs/riff_container.
	 */
	switch ( substr( $magic, 12, 4 ) ) {
		// Lossy WebP.
		case 'VP8 ':
			$parts  = unpack( 'v2', substr( $magic, 26, 4 ) );
			$width  = (int) ( $parts[1] & 0x3FFF );
			$height = (int) ( $parts[2] & 0x3FFF );
			$type   = 'lossy';
			break;
		// Lossless WebP.
		case 'VP8L':
			$parts  = unpack( 'C4', substr( $magic, 21, 4 ) );
			$width  = (int) ( $parts[1] | ( ( $parts[2] & 0x3F ) << 8 ) ) + 1;
			$height = (int) ( ( ( $parts[2] & 0xC0 ) >> 6 ) | ( $parts[3] << 2 ) | ( ( $parts[4] & 0x03 ) << 10 ) ) + 1;
			$type   = 'lossless';
			break;
		// Animated/alpha WebP.
		case 'VP8X':
			// Pad 24-bit int.
			$width = unpack( 'V', substr( $magic, 24, 3 ) . "\x00" );
			$width = (int) ( $width[1] & 0xFFFFFF ) + 1;
			// Pad 24-bit int.
			$height = unpack( 'V', substr( $magic, 27, 3 ) . "\x00" );
			$height = (int) ( $height[1] & 0xFFFFFF ) + 1;
			$type   = 'animated-alpha';
			break;
	}

	return compact( 'width', 'height', 'type' );
}

/**
 * Gets loading optimization attributes.
 *
 * This function returns an array of attributes that should be merged into the given attributes array to optimize
 * loading performance. Potential attributes returned by this function are:
 * - `loading` attribute with a value of "lazy"
 * - `fetchpriority` attribute with a value of "high"
 * - `decoding` attribute with a value of "async"
 *
 * If any of these attributes are already present in the given attributes, they will not be modified. Note that no
 * element should have both `loading="lazy"` and `fetchpriority="high"`, so the function will trigger a warning in case
 * both attributes are present with those values.
 *
 * @since 6.3.0
 *
 * @global WP_Query $wp_query WordPress Query object.
 *
 * @param string $tag_name The tag name.
 * @param array  $attr     Array of the attributes for the tag.
 * @param string $context  Context for the element for which the loading optimization attribute is requested.
 * @return array Loading optimization attributes.
 */
function wp_get_loading_optimization_attributes( $tag_name, $attr, $context ) {
	global $wp_query;

	/**
	 * Filters whether to short-circuit loading optimization attributes.
	 *
	 * Returning an array from the filter will effectively short-circuit the loading of optimization attributes,
	 * returning that value instead.
	 *
	 * @since 6.4.0
	 *
	 * @param array|false $loading_attrs False by default, or array of loading optimization attributes to short-circuit.
	 * @param string      $tag_name      The tag name.
	 * @param array       $attr          Array of the attributes for the tag.
	 * @param string      $context       Context for the element for which the loading optimization attribute is requested.
	 */
	$loading_attrs = apply_filters( 'pre_wp_get_loading_optimization_attributes', false, $tag_name, $attr, $context );

	if ( is_array( $loading_attrs ) ) {
		return $loading_attrs;
	}

	$loading_attrs = array();

	/*
	 * Skip lazy-loading for the overall block template, as it is handled more granularly.
	 * The skip is also applicable for `fetchpriority`.
	 */
	if ( 'template' === $context ) {
		/** This filter is documented in wp-includes/media.php */
		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );
	}

	// For now this function only supports images and iframes.
	if ( 'img' !== $tag_name && 'iframe' !== $tag_name ) {
		/** This filter is documented in wp-includes/media.php */
		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );
	}

	/*
	 * Skip programmatically created images within content blobs as they need to be handled together with the other
	 * images within the post content or widget content.
	 * Without this clause, they would already be considered within their own context which skews the image count and
	 * can result in the first post content image being lazy-loaded or an image further down the page being marked as a
	 * high priority.
	 */
	if (
		'the_content' !== $context && doing_filter( 'the_content' ) ||
		'widget_text_content' !== $context && doing_filter( 'widget_text_content' ) ||
		'widget_block_content' !== $context && doing_filter( 'widget_block_content' )
	) {
		/** This filter is documented in wp-includes/media.php */
		return apply_filters( 'wp_get_loading_optimization_attributes', $loading_attrs, $tag_name, $attr, $context );

	}

	/*
	 * Add `decoding` with a value of "async" for every image unless it has a
	 * conflicting `decoding` attribute already present.
	 */
	if ( 'img' === $tag_name ) {
		if ( isset( $attr['decoding'] ) ) {

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