X-Git-Url: https://scripts.mit.edu/gitweb/autoinstalls/wordpress.git/blobdiff_plain/874d2a2f468a0d1e69aab49b1fe2d9d79d3e1142..dc1231b7312fbdca99e9e887cc2bb35a28f85cdc:/wp-includes/media.php

diff --git a/wp-includes/media.php b/wp-includes/media.php
index 5e94cfeb..49d1717c 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -11,29 +11,33 @@
  *
  * This is so that the image is a better fit for the editor and theme.
  *
- * The $size parameter accepts either an array or a string. The supported string
+ * The `$size` parameter accepts either an array or a string. The supported string
  * values are 'thumb' or 'thumbnail' for the given thumbnail size or defaults at
  * 128 width and 96 height in pixels. Also supported for the string value is
  * 'medium' and 'full'. The 'full' isn't actually supported, but any value other
  * than the supported will result in the content_width size or 500 if that is
  * not set.
  *
- * Finally, there is a filter named 'editor_max_image_size', that will be called
- * on the calculated array for width and height, respectively. The second
+ * Finally, there is a filter named {@see 'editor_max_image_size'}, that will be
+ * called on the calculated array for width and height, respectively. The second
  * parameter will be the value that was in the $size parameter. The returned
  * type for the hook is an array with the width as the first element and the
  * height as the second element.
  *
  * @since 2.5.0
- * @uses wp_constrain_dimensions() This function passes the widths and the heights.
  *
- * @param int $width Width of the image
- * @param int $height Height of the image
- * @param string|array $size Size of what the result image should be.
- * @param context Could be 'display' (like in a theme) or 'edit' (like inserting into an editor)
+ * @global int   $content_width
+ * @global array $_wp_additional_image_sizes
+ *
+ * @param int          $width   Width of the image in pixels.
+ * @param int          $height  Height of the image in pixels.
+ * @param string|array $size    Optional. Size or array of sizes of what the result image
+ *                              should be. Accepts any valid image size name. Default 'medium'.
+ * @param string       $context Optional. Could be 'display' (like in a theme) or 'edit'
+ *                              (like inserting into an editor). Default null.
  * @return array Width and height of what the result image should resize to.
  */
-function image_constrain_size_for_editor($width, $height, $size = 'medium', $context = null ) {
+function image_constrain_size_for_editor( $width, $height, $size = 'medium', $context = null ) {
 	global $content_width, $_wp_additional_image_sizes;
 
 	if ( ! $context )
@@ -58,10 +62,12 @@ function image_constrain_size_for_editor($width, $height, $size = 'medium', $con
 		// if no width is set, default to the theme content width if available
 	}
 	elseif ( $size == 'large' ) {
-		// We're inserting a large size image into the editor. If it's a really
-		// big image we'll scale it down to fit reasonably within the editor
-		// itself, and within the theme's content width if it's known. The user
-		// can resize it in the editor if they wish.
+		/*
+		 * We're inserting a large size image into the editor. If it's a really
+		 * big image we'll scale it down to fit reasonably within the editor
+		 * itself, and within the theme's content width if it's known. The user
+		 * can resize it in the editor if they wish.
+		 */
 		$max_width = intval(get_option('large_size_w'));
 		$max_height = intval(get_option('large_size_h'));
 		if ( intval($content_width) > 0 )
@@ -108,11 +114,11 @@ function image_constrain_size_for_editor($width, $height, $size = 'medium', $con
  *
  * @since 2.5.0
  *
- * @param int|string $width Optional. Width attribute value.
- * @param int|string $height Optional. Height attribute value.
+ * @param int|string $width  Image width in pixels.
+ * @param int|string $height Image height in pixels.
  * @return string HTML attributes for width and, or height.
  */
-function image_hwstring($width, $height) {
+function image_hwstring( $width, $height ) {
 	$out = '';
 	if ($width)
 		$out .= 'width="'.intval($width).'" ';
@@ -139,11 +145,12 @@ function image_hwstring($width, $height) {
  *
  * @since 2.5.0
  *
- * @param int $id Attachment ID for image.
- * @param array|string $size Optional, default is 'medium'. Size of image, either array or string.
- * @return bool|array False on failure, array on success.
+ * @param int          $id   Attachment ID for image.
+ * @param array|string $size Optional. Image size to scale to. Accepts a registered image size
+ *                           or flat array of height and width values. Default 'medium'.
+ * @return false|array False on failure, array on success.
  */
-function image_downsize($id, $size = 'medium') {
+function image_downsize( $id, $size = 'medium' ) {
 
 	if ( !wp_attachment_is_image($id) )
 		return false;
@@ -215,12 +222,13 @@ function image_downsize($id, $size = 'medium') {
  *
  * @since 2.9.0
  *
+ * @global array $_wp_additional_image_sizes Associative array of additional image sizes.
+ *
  * @param string     $name   Image size identifier.
  * @param int        $width  Image width in pixels.
  * @param int        $height Image height in pixels.
  * @param bool|array $crop   Optional. Whether to crop images to specified height and width or resize.
  *                           An array can specify positioning of the crop area. Default false.
- * @return bool|array False, if no image was created. Metadata array on success.
  */
 function add_image_size( $name, $width = 0, $height = 0, $crop = false ) {
 	global $_wp_additional_image_sizes;
@@ -237,6 +245,8 @@ function add_image_size( $name, $width = 0, $height = 0, $crop = false ) {
  *
  * @since 3.9.0
  *
+ * @global array $_wp_additional_image_sizes
+ *
  * @param string $name The image size to check.
  * @return bool True if the image size exists, false if not.
  */
@@ -251,6 +261,8 @@ function has_image_size( $name ) {
  *
  * @since 3.9.0
  *
+ * @global array $_wp_additional_image_sizes
+ *
  * @param string $name The image size to remove.
  * @return bool True if the image size was successfully removed, false on failure.
  */
@@ -269,20 +281,20 @@ function remove_image_size( $name ) {
  * Registers an image size for the post thumbnail.
  *
  * @since 2.9.0
+ *
  * @see add_image_size() for details on cropping behavior.
  *
  * @param int        $width  Image width in pixels.
  * @param int        $height Image height in pixels.
  * @param bool|array $crop   Optional. Whether to crop images to specified height and width or resize.
  *                           An array can specify positioning of the crop area. Default false.
- * @return bool|array False, if no image was created. Metadata array on success.
  */
 function set_post_thumbnail_size( $width = 0, $height = 0, $crop = false ) {
 	add_image_size( 'post-thumbnail', $width, $height, $crop );
 }
 
 /**
- * An <img src /> tag for an image attachment, scaling it down if requested.
+ * Gets an img tag for an image attachment, scaling it down if requested.
  *
  * The filter 'get_image_tag_class' allows for changing the class name for the
  * image without having to use regular expressions on the HTML content. The
@@ -295,14 +307,15 @@ function set_post_thumbnail_size( $width = 0, $height = 0, $crop = false ) {
  *
  * @since 2.5.0
  *
- * @param int $id Attachment ID.
- * @param string $alt Image Description for the alt attribute.
- * @param string $title Image Description for the title attribute.
- * @param string $align Part of the class name for aligning the image.
- * @param string $size Optional. Default is 'medium'.
+ * @param int          $id    Attachment ID.
+ * @param string       $alt   Image Description for the alt attribute.
+ * @param string       $title Image Description for the title attribute.
+ * @param string       $align Part of the class name for aligning the image.
+ * @param string|array $size  Optional. Registered image size to retrieve a tag for, or flat array
+ *                            of height and width values. Default 'medium'.
  * @return string HTML IMG element for given image attachment
  */
-function get_image_tag($id, $alt, $title, $align, $size='medium') {
+function get_image_tag( $id, $alt, $title, $align, $size = 'medium' ) {
 
 	list( $img_src, $width, $height ) = image_downsize($id, $size);
 	$hwstring = image_hwstring($width, $height);
@@ -337,27 +350,25 @@ function get_image_tag($id, $alt, $title, $align, $size='medium') {
 	 * @param string $align Part of the class name for aligning the image.
 	 * @param string $size  Optional. Default is 'medium'.
 	 */
-	$html = apply_filters( 'get_image_tag', $html, $id, $alt, $title, $align, $size );
-
-	return $html;
+	return apply_filters( 'get_image_tag', $html, $id, $alt, $title, $align, $size );
 }
 
 /**
- * Calculates the new dimensions for a downsampled image.
+ * Calculates the new dimensions for a down-sampled image.
  *
  * If either width or height are empty, no constraint is applied on
  * that dimension.
  *
  * @since 2.5.0
  *
- * @param int $current_width Current width of the image.
+ * @param int $current_width  Current width of the image.
  * @param int $current_height Current height of the image.
- * @param int $max_width Optional. Maximum wanted width.
- * @param int $max_height Optional. Maximum wanted height.
+ * @param int $max_width      Optional. Max width in pixels to constrain to. Default 0.
+ * @param int $max_height     Optional. Max height in pixels to constrain to. Default 0.
  * @return array First item is the width, the second item is the height.
  */
-function wp_constrain_dimensions( $current_width, $current_height, $max_width=0, $max_height=0 ) {
-	if ( !$max_width and !$max_height )
+function wp_constrain_dimensions( $current_width, $current_height, $max_width = 0, $max_height = 0 ) {
+	if ( !$max_width && !$max_height )
 		return array( $current_width, $current_height );
 
 	$width_ratio = $height_ratio = 1.0;
@@ -377,30 +388,48 @@ function wp_constrain_dimensions( $current_width, $current_height, $max_width=0,
 	$smaller_ratio = min( $width_ratio, $height_ratio );
 	$larger_ratio  = max( $width_ratio, $height_ratio );
 
-	if ( intval( $current_width * $larger_ratio ) > $max_width || intval( $current_height * $larger_ratio ) > $max_height )
+	if ( (int) round( $current_width * $larger_ratio ) > $max_width || (int) round( $current_height * $larger_ratio ) > $max_height ) {
  		// The larger ratio is too big. It would result in an overflow.
 		$ratio = $smaller_ratio;
-	else
+	} else {
 		// The larger ratio fits, and is likely to be a more "snug" fit.
 		$ratio = $larger_ratio;
+	}
 
 	// Very small dimensions may result in 0, 1 should be the minimum.
-	$w = max ( 1, intval( $current_width  * $ratio ) );
-	$h = max ( 1, intval( $current_height * $ratio ) );
+	$w = max ( 1, (int) round( $current_width  * $ratio ) );
+	$h = max ( 1, (int) round( $current_height * $ratio ) );
 
 	// Sometimes, due to rounding, we'll end up with a result like this: 465x700 in a 177x177 box is 117x176... a pixel short
 	// We also have issues with recursive calls resulting in an ever-changing result. Constraining to the result of a constraint should yield the original result.
 	// Thus we look for dimensions that are one pixel shy of the max value and bump them up
-	if ( $did_width && $w == $max_width - 1 )
+
+	// Note: $did_width means it is possible $smaller_ratio == $width_ratio.
+	if ( $did_width && $w == $max_width - 1 ) {
 		$w = $max_width; // Round it up
-	if ( $did_height && $h == $max_height - 1 )
+	}
+
+	// Note: $did_height means it is possible $smaller_ratio == $height_ratio.
+	if ( $did_height && $h == $max_height - 1 ) {
 		$h = $max_height; // Round it up
+	}
 
-	return array( $w, $h );
+	/**
+	 * Filter dimensions to constrain down-sampled images to.
+	 *
+	 * @since 4.1.0
+	 *
+	 * @param array $dimensions     The image width and height.
+	 * @param int 	$current_width  The current width of the image.
+	 * @param int 	$current_height The current height of the image.
+	 * @param int 	$max_width      The maximum width permitted.
+	 * @param int 	$max_height     The maximum height permitted.
+	 */
+	return apply_filters( 'wp_constrain_dimensions', array( $w, $h ), $current_width, $current_height, $max_width, $max_height );
 }
 
 /**
- * Retrieve calculated resize dimensions for use in WP_Image_Editor.
+ * Retrieves calculated resize dimensions for use in WP_Image_Editor.
  *
  * Calculates dimensions and coordinates for a resized image that fits
  * within a specified width and height.
@@ -421,7 +450,7 @@ function wp_constrain_dimensions( $current_width, $current_height, $max_width=0,
  * @param int        $dest_h New height in pixels.
  * @param bool|array $crop   Optional. Whether to crop image to specified height and width or resize.
  *                           An array can specify positioning of the crop area. Default false.
- * @return bool|array False on failure. Returned array matches parameters for `imagecopyresampled()`.
+ * @return false|array False on failure. Returned array matches parameters for `imagecopyresampled()`.
  */
 function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = false) {
 
@@ -457,12 +486,12 @@ function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = fal
 		$new_w = min($dest_w, $orig_w);
 		$new_h = min($dest_h, $orig_h);
 
-		if ( !$new_w ) {
-			$new_w = intval($new_h * $aspect_ratio);
+		if ( ! $new_w ) {
+			$new_w = (int) round( $new_h * $aspect_ratio );
 		}
 
-		if ( !$new_h ) {
-			$new_h = intval($new_w / $aspect_ratio);
+		if ( ! $new_h ) {
+			$new_h = (int) round( $new_w / $aspect_ratio );
 		}
 
 		$size_ratio = max($new_w / $orig_w, $new_h / $orig_h);
@@ -503,8 +532,9 @@ function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = fal
 	}
 
 	// if the resulting image would be the same size or larger we don't want to resize it
-	if ( $new_w >= $orig_w && $new_h >= $orig_h )
+	if ( $new_w >= $orig_w && $new_h >= $orig_h && $dest_w != $orig_w && $dest_h != $orig_h ) {
 		return false;
+	}
 
 	// the return array matches the parameters to imagecopyresampled()
 	// int dst_x, int dst_y, int src_x, int src_y, int dst_w, int dst_h, int src_w, int src_h
@@ -513,7 +543,7 @@ function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = fal
 }
 
 /**
- * Resize an image to make a thumbnail or intermediate size.
+ * Resizes an image to make a thumbnail or intermediate size.
  *
  * The returned array has the file size, the image width, and image height. The
  * filter 'image_make_intermediate_size' can be used to hook in and change the
@@ -521,11 +551,12 @@ function image_resize_dimensions($orig_w, $orig_h, $dest_w, $dest_h, $crop = fal
  *
  * @since 2.5.0
  *
- * @param string $file File path.
- * @param int $width Image width.
- * @param int $height Image height.
- * @param bool $crop Optional, default is false. Whether to crop image to specified height and width or resize.
- * @return bool|array False, if no image was created. Metadata array on success.
+ * @param string $file   File path.
+ * @param int    $width  Image width.
+ * @param int    $height Image height.
+ * @param bool   $crop   Optional. Whether to crop image to specified height and width or resize.
+ *                       Default false.
+ * @return false|array False, if no image was created. Metadata array on success.
  */
 function image_make_intermediate_size( $file, $width, $height, $crop = false ) {
 	if ( $width || $height ) {
@@ -545,7 +576,7 @@ function image_make_intermediate_size( $file, $width, $height, $crop = false ) {
 }
 
 /**
- * Retrieve the image's intermediate size (resized) path, width, and height.
+ * Retrieves the image's intermediate size (resized) path, width, and height.
  *
  * The $size parameter can be an array with the width and height respectively.
  * If the size matches the 'sizes' metadata array for width and height, then it
@@ -564,18 +595,20 @@ function image_make_intermediate_size( $file, $width, $height, $crop = false ) {
  * browser scale down the image.
  *
  * @since 2.5.0
- * @see add_image_size()
  *
- * @param int $post_id Attachment ID for image.
- * @param array|string $size Optional, default is 'thumbnail'. Size of image, either array or string.
- * @return bool|array False on failure or array of file path, width, and height on success.
+ * @param int          $post_id Attachment ID.
+ * @param array|string $size    Optional. Registered image size to retrieve or flat array of height
+ *                              and width dimensions. Default 'thumbnail'.
+ * @return false|array False on failure or array of file path, width, and height on success.
  */
-function image_get_intermediate_size($post_id, $size='thumbnail') {
+function image_get_intermediate_size( $post_id, $size = 'thumbnail' ) {
 	if ( !is_array( $imagedata = wp_get_attachment_metadata( $post_id ) ) )
 		return false;
 
 	// get the best one for a specified set of dimensions
 	if ( is_array($size) && !empty($imagedata['sizes']) ) {
+		$areas = array();
+
 		foreach ( $imagedata['sizes'] as $_size => $data ) {
 			// already cropped to width or height; so use this size
 			if ( ( $data['width'] == $size[0] && $data['height'] <= $size[1] ) || ( $data['height'] == $size[1] && $data['width'] <= $size[0] ) ) {
@@ -621,9 +654,13 @@ function image_get_intermediate_size($post_id, $size='thumbnail') {
 }
 
 /**
- * Get the available image sizes
+ * Gets the available intermediate image sizes.
+ *
  * @since 3.0.0
- * @return array Returns a filtered array of image size strings
+ *
+ * @global array $_wp_additional_image_sizes
+ *
+ * @return array Returns a filtered array of image size strings.
  */
 function get_intermediate_image_sizes() {
 	global $_wp_additional_image_sizes;
@@ -649,62 +686,75 @@ function get_intermediate_image_sizes() {
  *
  * @since 2.5.0
  *
- * @param int $attachment_id Image attachment ID.
- * @param string $size Optional, default is 'thumbnail'.
- * @param bool $icon Optional, default is false. Whether it is an icon.
- * @return bool|array Returns an array (url, width, height), or false, if no image is available.
+ * @param int          $attachment_id Image attachment ID.
+ * @param string|array $size          Optional. Registered image size to retrieve the source for or a flat
+ *                                    array of height and width dimensions. Default 'thumbnail'.
+ * @param bool         $icon          Optional. Whether the image should be treated as an icon. Default false.
+ * @return false|array Returns an array (url, width, height), or false, if no image is available.
  */
-function wp_get_attachment_image_src($attachment_id, $size='thumbnail', $icon = false) {
-
+function wp_get_attachment_image_src( $attachment_id, $size = 'thumbnail', $icon = false ) {
 	// get a thumbnail or intermediate image if there is one
-	if ( $image = image_downsize($attachment_id, $size) )
-		return $image;
+	$image = image_downsize( $attachment_id, $size );
+	if ( ! $image ) {
+		$src = false;
 
-	$src = false;
+		if ( $icon && $src = wp_mime_type_icon( $attachment_id ) ) {
+			/** This filter is documented in wp-includes/post.php */
+			$icon_dir = apply_filters( 'icon_dir', ABSPATH . WPINC . '/images/media' );
 
-	if ( $icon && $src = wp_mime_type_icon($attachment_id) ) {
-		/** This filter is documented in wp-includes/post.php */
-		$icon_dir = apply_filters( 'icon_dir', ABSPATH . WPINC . '/images/media' );
-		$src_file = $icon_dir . '/' . wp_basename($src);
-		@list($width, $height) = getimagesize($src_file);
+			$src_file = $icon_dir . '/' . wp_basename( $src );
+			@list( $width, $height ) = getimagesize( $src_file );
+		}
+
+		if ( $src && $width && $height ) {
+			$image = array( $src, $width, $height );
+		}
 	}
-	if ( $src && $width && $height )
-		return array( $src, $width, $height );
-	return false;
+	/**
+	 * Filter the image src result.
+	 *
+	 * @since 4.3.0
+	 *
+	 * @param array|false  $image         Either array with src, width & height, icon src, or false.
+	 * @param int          $attachment_id Image attachment ID.
+	 * @param string|array $size          Registered image size to retrieve the source for or a flat
+	 *                                    array of height and width dimensions. Default 'thumbnail'.
+	 * @param bool         $icon          Whether the image should be treated as an icon. Default false.
+	 */
+	return apply_filters( 'wp_get_attachment_image_src', $image, $attachment_id, $size, $icon );
 }
 
 /**
  * Get an HTML img element representing an image attachment
  *
- * While $size will accept an array, it is better to register a size with
+ * While `$size` will accept an array, it is better to register a size with
  * add_image_size() so that a cropped version is generated. It's much more
  * efficient than having to find the closest-sized image and then having the
  * browser scale down the image.
  *
  * @since 2.5.0
  *
- * @see add_image_size()
- * @uses wp_get_attachment_image_src() Gets attachment file URL and dimensions
- *
- * @param int $attachment_id Image attachment ID.
- * @param string $size Optional, default is 'thumbnail'.
- * @param bool $icon Optional, default is false. Whether it is an icon.
- * @param mixed $attr Optional, attributes for the image markup.
+ * @param int          $attachment_id Image attachment ID.
+ * @param string|array $size          Optional. Registered image size or flat array of height and width
+ *                                    dimensions. Default 'thumbnail'.
+ * @param bool         $icon          Optional. Whether the image should be treated as an icon. Default false.
+ * @param string|array $attr          Optional. Attributes for the image markup. Default empty.
  * @return string HTML img element or empty string on failure.
  */
 function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = false, $attr = '') {
-
 	$html = '';
 	$image = wp_get_attachment_image_src($attachment_id, $size, $icon);
 	if ( $image ) {
 		list($src, $width, $height) = $image;
 		$hwstring = image_hwstring($width, $height);
-		if ( is_array($size) )
-			$size = join('x', $size);
+		$size_class = $size;
+		if ( is_array( $size_class ) ) {
+			$size_class = join( 'x', $size_class );
+		}
 		$attachment = get_post($attachment_id);
 		$default_attr = array(
 			'src'	=> $src,
-			'class'	=> "attachment-$size",
+			'class'	=> "attachment-$size_class",
 			'alt'	=> trim(strip_tags( get_post_meta($attachment_id, '_wp_attachment_image_alt', true) )), // Use Alt field first
 		);
 		if ( empty($default_attr['alt']) )
@@ -719,10 +769,11 @@ function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = fa
 		 *
 		 * @since 2.8.0
 		 *
-		 * @param mixed $attr          Attributes for the image markup.
-		 * @param int   $attachment_id Image attachment ID.
+		 * @param array        $attr       Attributes for the image markup.
+		 * @param WP_Post      $attachment Image attachment post.
+		 * @param string|array $size       Requested size.
 		 */
-		$attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment );
+		$attr = apply_filters( 'wp_get_attachment_image_attributes', $attr, $attachment, $size );
 		$attr = array_map( 'esc_attr', $attr );
 		$html = rtrim("<img $hwstring");
 		foreach ( $attr as $name => $value ) {
@@ -735,13 +786,16 @@ function wp_get_attachment_image($attachment_id, $size = 'thumbnail', $icon = fa
 }
 
 /**
- * Adds a 'wp-post-image' class to post thumbnails
- * Uses the begin_fetch_post_thumbnail_html and end_fetch_post_thumbnail_html action hooks to
- * dynamically add/remove itself so as to only filter post thumbnails
+ * Adds a 'wp-post-image' class to post thumbnails. Internal use only.
+ *
+ * Uses the 'begin_fetch_post_thumbnail_html' and 'end_fetch_post_thumbnail_html' action hooks to
+ * dynamically add/remove itself so as to only filter post thumbnails.
  *
+ * @ignore
  * @since 2.9.0
- * @param array $attr Attributes including src, class, alt, title
- * @return array
+ *
+ * @param array $attr Thumbnail attributes including src, class, alt, title.
+ * @return array Modified array of attributes including the new 'wp-post-image' class.
  */
 function _wp_post_thumbnail_class_filter( $attr ) {
 	$attr['class'] .= ' wp-post-image';
@@ -749,18 +803,26 @@ function _wp_post_thumbnail_class_filter( $attr ) {
 }
 
 /**
- * Adds _wp_post_thumbnail_class_filter to the wp_get_attachment_image_attributes filter
+ * Adds '_wp_post_thumbnail_class_filter' callback to the 'wp_get_attachment_image_attributes'
+ * filter hook. Internal use only.
  *
+ * @ignore
  * @since 2.9.0
+ *
+ * @param array $attr Thumbnail attributes including src, class, alt, title.
  */
 function _wp_post_thumbnail_class_filter_add( $attr ) {
 	add_filter( 'wp_get_attachment_image_attributes', '_wp_post_thumbnail_class_filter' );
 }
 
 /**
- * Removes _wp_post_thumbnail_class_filter from the wp_get_attachment_image_attributes filter
+ * Removes the '_wp_post_thumbnail_class_filter' callback from the 'wp_get_attachment_image_attributes'
+ * filter hook. Internal use only.
  *
+ * @ignore
  * @since 2.9.0
+ *
+ * @param array $attr Thumbnail attributes including src, class, alt, title.
  */
 function _wp_post_thumbnail_class_filter_remove( $attr ) {
 	remove_filter( 'wp_get_attachment_image_attributes', '_wp_post_thumbnail_class_filter' );
@@ -770,7 +832,7 @@ add_shortcode('wp_caption', 'img_caption_shortcode');
 add_shortcode('caption', 'img_caption_shortcode');
 
 /**
- * The Caption shortcode.
+ * Builds the Caption shortcode output.
  *
  * Allows a plugin to replace the content that would otherwise be returned. The
  * filter is 'img_caption_shortcode' and passes an empty string, the attr
@@ -781,7 +843,7 @@ add_shortcode('caption', 'img_caption_shortcode');
  *
  * @since 2.6.0
  *
- * @param array $attr {
+ * @param array  $attr {
  *     Attributes of the caption shortcode.
  *
  *     @type string $id      ID of the div element for the caption.
@@ -791,7 +853,7 @@ add_shortcode('caption', 'img_caption_shortcode');
  *     @type string $caption The caption text.
  *     @type string $class   Additional class name(s) added to the caption container.
  * }
- * @param string $content Optional. Shortcode content.
+ * @param string $content Shortcode content.
  * @return string HTML content to display the caption.
  */
 function img_caption_shortcode( $attr, $content = null ) {
@@ -801,6 +863,8 @@ function img_caption_shortcode( $attr, $content = null ) {
 			$content = $matches[1];
 			$attr['caption'] = trim( $matches[2] );
 		}
+	} elseif ( strpos( $attr['caption'], '<' ) !== false ) {
+		$attr['caption'] = wp_kses( $attr['caption'], 'post' );
 	}
 
 	/**
@@ -834,7 +898,7 @@ function img_caption_shortcode( $attr, $content = null ) {
 		return $content;
 
 	if ( ! empty( $atts['id'] ) )
-		$atts['id'] = 'id="' . esc_attr( $atts['id'] ) . '" ';
+		$atts['id'] = 'id="' . esc_attr( sanitize_html_class( $atts['id'] ) ) . '" ';
 
 	$class = trim( 'wp-caption ' . $atts['align'] . ' ' . $atts['class'] );
 
@@ -873,13 +937,15 @@ function img_caption_shortcode( $attr, $content = null ) {
 add_shortcode('gallery', 'gallery_shortcode');
 
 /**
- * The Gallery shortcode.
+ * Builds the Gallery shortcode output.
  *
  * This implements the functionality of the Gallery Shortcode for displaying
  * WordPress images on a post.
  *
  * @since 2.5.0
  *
+ * @staticvar int $instance
+ *
  * @param array $attr {
  *     Attributes of the gallery shortcode.
  *
@@ -924,25 +990,19 @@ function gallery_shortcode( $attr ) {
 	 * the default gallery template.
 	 *
 	 * @since 2.5.0
+	 * @since 4.2.0 The `$instance` parameter was added.
 	 *
 	 * @see gallery_shortcode()
 	 *
-	 * @param string $output The gallery output. Default empty.
-	 * @param array  $attr   Attributes of the gallery shortcode.
+	 * @param string $output   The gallery output. Default empty.
+	 * @param array  $attr     Attributes of the gallery shortcode.
+	 * @param int    $instance Unique numeric ID of this gallery shortcode instance.
 	 */
-	$output = apply_filters( 'post_gallery', '', $attr );
+	$output = apply_filters( 'post_gallery', '', $attr, $instance );
 	if ( $output != '' ) {
 		return $output;
 	}
 
-	// We're trusting author input, so let's at least make sure it looks like a valid orderby statement
-	if ( isset( $attr['orderby'] ) ) {
-		$attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
-		if ( ! $attr['orderby'] ) {
-			unset( $attr['orderby'] );
-		}
-	}
-
 	$html5 = current_theme_supports( 'html5', 'gallery' );
 	$atts = shortcode_atts( array(
 		'order'      => 'ASC',
@@ -959,9 +1019,6 @@ function gallery_shortcode( $attr ) {
 	), $attr, 'gallery' );
 
 	$id = intval( $atts['id'] );
-	if ( 'RAND' == $atts['order'] ) {
-		$atts['orderby'] = 'none';
-	}
 
 	if ( ! empty( $atts['include'] ) ) {
 		$_attachments = get_posts( array( 'include' => $atts['include'], 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $atts['order'], 'orderby' => $atts['orderby'] ) );
@@ -1049,19 +1106,21 @@ function gallery_shortcode( $attr ) {
 	 *
 	 * @since 2.5.0
 	 *
-	 * @param string $gallery_style Default gallery shortcode CSS styles.
-	 * @param string $gallery_div   Opening HTML div container for the gallery shortcode output.
+	 * @param string $gallery_style Default CSS styles and opening HTML div container
+	 *                              for the gallery shortcode output.
 	 */
 	$output = apply_filters( 'gallery_style', $gallery_style . $gallery_div );
 
 	$i = 0;
 	foreach ( $attachments as $id => $attachment ) {
+
+		$attr = ( trim( $attachment->post_excerpt ) ) ? array( 'aria-describedby' => "$selector-$id" ) : '';
 		if ( ! empty( $atts['link'] ) && 'file' === $atts['link'] ) {
-			$image_output = wp_get_attachment_link( $id, $atts['size'], false, false );
+			$image_output = wp_get_attachment_link( $id, $atts['size'], false, false, false, $attr );
 		} elseif ( ! empty( $atts['link'] ) && 'none' === $atts['link'] ) {
-			$image_output = wp_get_attachment_image( $id, $atts['size'], false );
+			$image_output = wp_get_attachment_image( $id, $atts['size'], false, $attr );
 		} else {
-			$image_output = wp_get_attachment_link( $id, $atts['size'], true, false );
+			$image_output = wp_get_attachment_link( $id, $atts['size'], true, false, false, $attr );
 		}
 		$image_meta  = wp_get_attachment_metadata( $id );
 
@@ -1076,7 +1135,7 @@ function gallery_shortcode( $attr ) {
 			</{$icontag}>";
 		if ( $captiontag && trim($attachment->post_excerpt) ) {
 			$output .= "
-				<{$captiontag} class='wp-caption-text gallery-caption'>
+				<{$captiontag} class='wp-caption-text gallery-caption' id='$selector-$id'>
 				" . wptexturize($attachment->post_excerpt) . "
 				</{$captiontag}>";
 		}
@@ -1098,7 +1157,7 @@ function gallery_shortcode( $attr ) {
 }
 
 /**
- * Output the templates used by playlists.
+ * Outputs the templates used by playlists.
  *
  * @since 3.9.0
  */
@@ -1136,7 +1195,7 @@ function wp_underscore_playlist_templates() {
 }
 
 /**
- * Output and enqueue default scripts and styles for playlists.
+ * Outputs and enqueue default scripts and styles for playlists.
  *
  * @since 3.9.0
  *
@@ -1151,22 +1210,24 @@ function wp_playlist_scripts( $type ) {
 	add_action( 'wp_footer', 'wp_underscore_playlist_templates', 0 );
 	add_action( 'admin_footer', 'wp_underscore_playlist_templates', 0 );
 }
-add_action( 'wp_playlist_scripts', 'wp_playlist_scripts' );
 
 /**
- * The playlist shortcode.
+ * Builds the Playlist shortcode output.
  *
  * This implements the functionality of the playlist shortcode for displaying
  * a collection of WordPress audio or video files in a post.
  *
  * @since 3.9.0
  *
+ * @global int $content_width
+ * @staticvar int $instance
+ *
  * @param array $attr {
  *     Array of default playlist attributes.
  *
  *     @type string  $type         Type of playlist to display. Accepts 'audio' or 'video'. Default 'audio'.
  *     @type string  $order        Designates ascending or descending order of items in the playlist.
- *                                 Accepts 'ASC', 'DESC', or 'RAND'. Default 'ASC'.
+ *                                 Accepts 'ASC', 'DESC'. Default 'ASC'.
  *     @type string  $orderby      Any column, or columns, to sort the playlist. If $ids are
  *                                 passed, this defaults to the order of the $ids array ('post__in').
  *                                 Otherwise default is 'menu_order ID'.
@@ -1209,25 +1270,17 @@ function wp_playlist_shortcode( $attr ) {
 	 * of the default playlist output, returning the passed value instead.
 	 *
 	 * @since 3.9.0
+	 * @since 4.2.0 The `$instance` parameter was added.
 	 *
-	 * @param string $output Playlist output. Default empty.
-	 * @param array  $attr   An array of shortcode attributes.
+	 * @param string $output   Playlist output. Default empty.
+	 * @param array  $attr     An array of shortcode attributes.
+	 * @param int    $instance Unique numeric ID of this playlist shortcode instance.
 	 */
-	$output = apply_filters( 'post_playlist', '', $attr );
+	$output = apply_filters( 'post_playlist', '', $attr, $instance );
 	if ( $output != '' ) {
 		return $output;
 	}
 
-	/*
-	 * We're trusting author input, so let's at least make sure it looks
-	 * like a valid orderby statement.
-	 */
-	if ( isset( $attr['orderby'] ) ) {
-		$attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
-		if ( ! $attr['orderby'] )
-			unset( $attr['orderby'] );
-	}
-
 	$atts = shortcode_atts( array(
 		'type'		=> 'audio',
 		'order'		=> 'ASC',
@@ -1243,9 +1296,6 @@ function wp_playlist_shortcode( $attr ) {
 	), $attr, 'playlist' );
 
 	$id = intval( $atts['id'] );
-	if ( 'RAND' == $atts['order'] ) {
-		$atts['orderby'] = 'none';
-	}
 
 	if ( $atts['type'] !== 'audio' ) {
 		$atts['type'] = 'video';
@@ -1403,7 +1453,7 @@ function wp_playlist_shortcode( $attr ) {
 	}
 	?></ol>
 	</noscript>
-	<script type="application/json" class="wp-playlist-script"><?php echo json_encode( $data ) ?></script>
+	<script type="application/json" class="wp-playlist-script"><?php echo wp_json_encode( $data ) ?></script>
 </div>
 	<?php
 	return ob_get_clean();
@@ -1411,12 +1461,12 @@ function wp_playlist_shortcode( $attr ) {
 add_shortcode( 'playlist', 'wp_playlist_shortcode' );
 
 /**
- * Provide a No-JS Flash fallback as a last resort for audio / video
+ * Provides a No-JS Flash fallback as a last resort for audio / video.
  *
  * @since 3.6.0
  *
- * @param string $url
- * @return string Fallback HTML
+ * @param string $url The media element URL.
+ * @return string Fallback HTML.
  */
 function wp_mediaelement_fallback( $url ) {
 	/**
@@ -1431,10 +1481,11 @@ function wp_mediaelement_fallback( $url ) {
 }
 
 /**
- * Return a filtered list of WP-supported audio formats.
+ * Returns a filtered list of WP-supported audio formats.
  *
  * @since 3.6.0
- * @return array
+ *
+ * @return array Supported audio formats.
  */
 function wp_get_audio_extensions() {
 	/**
@@ -1449,12 +1500,12 @@ function wp_get_audio_extensions() {
 }
 
 /**
- * Return useful keys to use to lookup data from an attachment's stored metadata.
+ * Returns useful keys to use to lookup data from an attachment's stored metadata.
  *
  * @since 3.9.0
  *
  * @param WP_Post $attachment The current attachment, provided for context.
- * @param string  $context    The context. Accepts 'edit', 'display'. Default 'display'.
+ * @param string  $context    Optional. The context. Accepts 'edit', 'display'. Default 'display'.
  * @return array Key/value pairs of field keys to labels.
  */
 function wp_get_attachment_id3_keys( $attachment, $context = 'display' ) {
@@ -1484,14 +1535,16 @@ function wp_get_attachment_id3_keys( $attachment, $context = 'display' ) {
 	return apply_filters( 'wp_get_attachment_id3_keys', $fields, $attachment, $context );
 }
 /**
- * The Audio shortcode.
+ * Builds the Audio shortcode output.
  *
  * This implements the functionality of the Audio Shortcode for displaying
  * WordPress mp3s in a post.
  *
  * @since 3.6.0
  *
- * @param array $attr {
+ * @staticvar int $instance
+ *
+ * @param array  $attr {
  *     Attributes of the audio shortcode.
  *
  *     @type string $src      URL to the source of the audio file. Default empty.
@@ -1499,17 +1552,16 @@ function wp_get_attachment_id3_keys( $attachment, $context = 'display' ) {
  *     @type string $autoplay The 'autoplay' attribute for the `<audio>` element. Default empty.
  *     @type string $preload  The 'preload' attribute for the `<audio>` element. Default empty.
  *     @type string $class    The 'class' attribute for the `<audio>` element. Default 'wp-audio-shortcode'.
- *     @type string $id       The 'id' attribute for the `<audio>` element. Default 'audio-{$post_id}-{$instances}'.
  *     @type string $style    The 'style' attribute for the `<audio>` element. Default 'width: 100%'.
  * }
- * @param string $content Optional. Shortcode content.
- * @return string HTML content to display audio.
+ * @param string $content Shortcode content.
+ * @return string|void HTML content to display audio.
  */
 function wp_audio_shortcode( $attr, $content = '' ) {
 	$post_id = get_post() ? get_the_ID() : 0;
 
-	static $instances = 0;
-	$instances++;
+	static $instance = 0;
+	$instance++;
 
 	/**
 	 * Filter the default audio shortcode output.
@@ -1518,12 +1570,12 @@ function wp_audio_shortcode( $attr, $content = '' ) {
 	 *
 	 * @since 3.6.0
 	 *
-	 * @param string $html      Empty variable to be replaced with shortcode markup.
-	 * @param array  $attr      Attributes of the shortcode. @see wp_audio_shortcode()
-	 * @param string $content   Shortcode content.
-	 * @param int    $instances Unique numeric ID of this audio shortcode instance.
+	 * @param string $html     Empty variable to be replaced with shortcode markup.
+	 * @param array  $attr     Attributes of the shortcode. @see wp_audio_shortcode()
+	 * @param string $content  Shortcode content.
+	 * @param int    $instance Unique numeric ID of this audio shortcode instance.
 	 */
-	$override = apply_filters( 'wp_audio_shortcode_override', '', $attr, $content, $instances );
+	$override = apply_filters( 'wp_audio_shortcode_override', '', $attr, $content, $instance );
 	if ( '' !== $override ) {
 		return $override;
 	}
@@ -1599,7 +1651,7 @@ function wp_audio_shortcode( $attr, $content = '' ) {
 	 */
 	$html_atts = array(
 		'class'    => apply_filters( 'wp_audio_shortcode_class', 'wp-audio-shortcode' ),
-		'id'       => sprintf( 'audio-%d-%d', $post_id, $instances ),
+		'id'       => sprintf( 'audio-%d-%d', $post_id, $instance ),
 		'loop'     => wp_validate_boolean( $atts['loop'] ),
 		'autoplay' => wp_validate_boolean( $atts['autoplay'] ),
 		'preload'  => $atts['preload'],
@@ -1619,7 +1671,7 @@ function wp_audio_shortcode( $attr, $content = '' ) {
 	}
 
 	$html = '';
-	if ( 'mediaelement' === $library && 1 === $instances ) {
+	if ( 'mediaelement' === $library && 1 === $instance ) {
 		$html .= "<!--[if lt IE 9]><script>document.createElement('audio');</script><![endif]-->\n";
 	}
 	$html .= sprintf( '<audio %s controls="controls">', join( ' ', $attr_strings ) );
@@ -1632,7 +1684,7 @@ function wp_audio_shortcode( $attr, $content = '' ) {
 				$fileurl = $atts[ $fallback ];
 			}
 			$type = wp_check_filetype( $atts[ $fallback ], wp_get_mime_types() );
-			$url = add_query_arg( '_', $instances, $atts[ $fallback ] );
+			$url = add_query_arg( '_', $instance, $atts[ $fallback ] );
 			$html .= sprintf( $source, $type['type'], esc_url( $url ) );
 		}
 	}
@@ -1658,10 +1710,11 @@ function wp_audio_shortcode( $attr, $content = '' ) {
 add_shortcode( 'audio', 'wp_audio_shortcode' );
 
 /**
- * Return a filtered list of WP-supported video formats
+ * Returns a filtered list of WP-supported video formats.
  *
  * @since 3.6.0
- * @return array
+ *
+ * @return array List of supported video formats.
  */
 function wp_get_video_extensions() {
 	/**
@@ -1676,14 +1729,17 @@ function wp_get_video_extensions() {
 }
 
 /**
- * The Video shortcode.
+ * Builds the Video shortcode output.
  *
  * This implements the functionality of the Video Shortcode for displaying
  * WordPress mp4s in a post.
  *
  * @since 3.6.0
  *
- * @param array $attr {
+ * @global int $content_width
+ * @staticvar int $instance
+ *
+ * @param array  $attr {
  *     Attributes of the shortcode.
  *
  *     @type string $src      URL to the source of the video file. Default empty.
@@ -1696,18 +1752,16 @@ function wp_get_video_extensions() {
  *                            Default 'metadata'.
  *     @type string $class    The 'class' attribute for the `<video>` element.
  *                            Default 'wp-video-shortcode'.
- *     @type string $id       The 'id' attribute for the `<video>` element.
- *                            Default 'video-{$post_id}-{$instances}'.
  * }
- * @param string $content Optional. Shortcode content.
- * @return string HTML content to display video.
+ * @param string $content Shortcode content.
+ * @return string|void HTML content to display video.
  */
 function wp_video_shortcode( $attr, $content = '' ) {
 	global $content_width;
 	$post_id = get_post() ? get_the_ID() : 0;
 
-	static $instances = 0;
-	$instances++;
+	static $instance = 0;
+	$instance++;
 
 	/**
 	 * Filter the default video shortcode output.
@@ -1719,12 +1773,12 @@ function wp_video_shortcode( $attr, $content = '' ) {
 	 *
 	 * @see wp_video_shortcode()
 	 *
-	 * @param string $html      Empty variable to be replaced with shortcode markup.
-	 * @param array  $attr      Attributes of the video shortcode.
-	 * @param string $content   Video shortcode content.
-	 * @param int    $instances Unique numeric ID of this video shortcode instance.
+	 * @param string $html     Empty variable to be replaced with shortcode markup.
+	 * @param array  $attr     Attributes of the video shortcode.
+	 * @param string $content  Video shortcode content.
+	 * @param int    $instance Unique numeric ID of this video shortcode instance.
 	 */
-	$override = apply_filters( 'wp_video_shortcode_override', '', $attr, $content, $instances );
+	$override = apply_filters( 'wp_video_shortcode_override', '', $attr, $content, $instance );
 	if ( '' !== $override ) {
 		return $override;
 	}
@@ -1762,16 +1816,25 @@ function wp_video_shortcode( $attr, $content = '' ) {
 		}
 	}
 
+	$is_vimeo = $is_youtube = false;
 	$yt_pattern = '#^https?://(?:www\.)?(?:youtube\.com/watch|youtu\.be/)#';
+	$vimeo_pattern = '#^https?://(.+\.)?vimeo\.com/.*#';
 
 	$primary = false;
 	if ( ! empty( $atts['src'] ) ) {
-		if ( ! preg_match( $yt_pattern, $atts['src'] ) ) {
+		$is_vimeo = ( preg_match( $vimeo_pattern, $atts['src'] ) );
+		$is_youtube = (  preg_match( $yt_pattern, $atts['src'] ) );
+		if ( ! $is_youtube && ! $is_vimeo ) {
 			$type = wp_check_filetype( $atts['src'], wp_get_mime_types() );
 			if ( ! in_array( strtolower( $type['ext'] ), $default_types ) ) {
 				return sprintf( '<a class="wp-embedded-video" href="%s">%s</a>', esc_url( $atts['src'] ), esc_html( $atts['src'] ) );
 			}
 		}
+
+		if ( $is_vimeo ) {
+			wp_enqueue_script( 'froogaloop' );
+		}
+
 		$primary = true;
 		array_unshift( $default_types, 'src' );
 	} else {
@@ -1822,7 +1885,7 @@ function wp_video_shortcode( $attr, $content = '' ) {
 	 */
 	$html_atts = array(
 		'class'    => apply_filters( 'wp_video_shortcode_class', 'wp-video-shortcode' ),
-		'id'       => sprintf( 'video-%d-%d', $post_id, $instances ),
+		'id'       => sprintf( 'video-%d-%d', $post_id, $instance ),
 		'width'    => absint( $atts['width'] ),
 		'height'   => absint( $atts['height'] ),
 		'poster'   => esc_url( $atts['poster'] ),
@@ -1844,7 +1907,7 @@ function wp_video_shortcode( $attr, $content = '' ) {
 	}
 
 	$html = '';
-	if ( 'mediaelement' === $library && 1 === $instances ) {
+	if ( 'mediaelement' === $library && 1 === $instance ) {
 		$html .= "<!--[if lt IE 9]><script>document.createElement('video');</script><![endif]-->\n";
 	}
 	$html .= sprintf( '<video %s controls="controls">', join( ' ', $attr_strings ) );
@@ -1856,12 +1919,14 @@ function wp_video_shortcode( $attr, $content = '' ) {
 			if ( empty( $fileurl ) ) {
 				$fileurl = $atts[ $fallback ];
 			}
-			if ( 'src' === $fallback && preg_match( $yt_pattern, $atts['src'] ) ) {
+			if ( 'src' === $fallback && $is_youtube ) {
 				$type = array( 'type' => 'video/youtube' );
+			} elseif ( 'src' === $fallback && $is_vimeo ) {
+				$type = array( 'type' => 'video/vimeo' );
 			} else {
 				$type = wp_check_filetype( $atts[ $fallback ], wp_get_mime_types() );
 			}
-			$url = add_query_arg( '_', $instances, $atts[ $fallback ] );
+			$url = add_query_arg( '_', $instance, $atts[ $fallback ] );
 			$html .= sprintf( $source, $type['type'], esc_url( $url ) );
 		}
 	}
@@ -1878,14 +1943,11 @@ function wp_video_shortcode( $attr, $content = '' ) {
 	}
 	$html .= '</video>';
 
-	$width_rule = $height_rule = '';
+	$width_rule = '';
 	if ( ! empty( $atts['width'] ) ) {
 		$width_rule = sprintf( 'width: %dpx; ', $atts['width'] );
 	}
-	if ( ! empty( $atts['height'] ) ) {
-		$height_rule = sprintf( 'height: %dpx; ', $atts['height'] );
-	}
-	$output = sprintf( '<div style="%s%s" class="wp-video">%s</div>', $width_rule, $height_rule, $html );
+	$output = sprintf( '<div style="%s" class="wp-video">%s</div>', $width_rule, $html );
 
 	/**
 	 * Filter the output of the video shortcode.
@@ -1903,39 +1965,48 @@ function wp_video_shortcode( $attr, $content = '' ) {
 add_shortcode( 'video', 'wp_video_shortcode' );
 
 /**
- * Display previous image link that has the same post parent.
+ * Displays previous image link that has the same post parent.
  *
  * @since 2.5.0
- * @param string $size Optional, default is 'thumbnail'. Size of image, either array or string. 0 or 'none' will default to post_title or $text;
- * @param string $text Optional, default is false. If included, link will reflect $text variable.
- * @return string HTML content.
+ *
+ * @see adjacent_image_link()
+ *
+ * @param string|array $size Optional. Registered image size or flat array of height and width dimensions.
+ *                           0 or 'none' will default to 'post_title' or `$text`. Default 'thumbnail'.
+ * @param string       $text Optional. Link text. Default false.
  */
-function previous_image_link($size = 'thumbnail', $text = false) {
+function previous_image_link( $size = 'thumbnail', $text = false ) {
 	adjacent_image_link(true, $size, $text);
 }
 
 /**
- * Display next image link that has the same post parent.
+ * Displays next image link that has the same post parent.
  *
  * @since 2.5.0
- * @param string $size Optional, default is 'thumbnail'. Size of image, either array or string. 0 or 'none' will default to post_title or $text;
- * @param string $text Optional, default is false. If included, link will reflect $text variable.
- * @return string HTML content.
+ *
+ * @see adjacent_image_link()
+ *
+ * @param string|array $size Optional. Registered image size or flat array of height and width dimensions.
+ *                           0 or 'none' will default to 'post_title' or `$text`. Default 'thumbnail'.
+ * @param string       $text Optional. Link text. Default false.
  */
 function next_image_link($size = 'thumbnail', $text = false) {
 	adjacent_image_link(false, $size, $text);
 }
 
 /**
- * Display next or previous image link that has the same post parent.
+ * Displays next or previous image link that has the same post parent.
  *
  * Retrieves the current attachment object from the $post global.
  *
  * @since 2.5.0
  *
- * @param bool $prev Optional. Default is true to display previous link, false for next.
+ * @param bool         $prev Optional. Whether to display the next (false) or previous (true) link. Default true.
+ * @param string|array $size Optional. Registered image size or flat array of height and width dimensions.
+ *                                     Default 'thumbnail'.
+ * @param bool         $text Optional. Link text. Default false.
  */
-function adjacent_image_link($prev = true, $size = 'thumbnail', $text = false) {
+function adjacent_image_link( $prev = true, $size = 'thumbnail', $text = false ) {
 	$post = get_post();
 	$attachments = array_values( get_children( array( 'post_parent' => $post->post_parent, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => 'ASC', 'orderby' => 'menu_order ID' ) ) );
 
@@ -1962,7 +2033,7 @@ function adjacent_image_link($prev = true, $size = 'thumbnail', $text = false) {
 	/**
 	 * Filter the adjacent image link.
 	 *
-	 * The dynamic portion of the hook name, $adjacent, refers to the type of adjacency,
+	 * The dynamic portion of the hook name, `$adjacent`, refers to the type of adjacency,
 	 * either 'next', or 'previous'.
 	 *
 	 * @since 3.5.0
@@ -1976,19 +2047,19 @@ function adjacent_image_link($prev = true, $size = 'thumbnail', $text = false) {
 }
 
 /**
- * Retrieve taxonomies attached to the attachment.
+ * Retrieves taxonomies attached to given the attachment.
  *
  * @since 2.5.0
  *
- * @param int|array|object $attachment Attachment ID, Attachment data array, or Attachment data object.
+ * @param int|array|object $attachment Attachment ID, data array, or data object.
  * @return array Empty array on failure. List of taxonomies on success.
  */
-function get_attachment_taxonomies($attachment) {
-	if ( is_int( $attachment ) )
-		$attachment = get_post($attachment);
-	else if ( is_array($attachment) )
+function get_attachment_taxonomies( $attachment ) {
+	if ( is_int( $attachment ) ) {
+		$attachment = get_post( $attachment );
+	} elseif ( is_array( $attachment ) ) {
 		$attachment = (object) $attachment;
-
+	}
 	if ( ! is_object($attachment) )
 		return array();
 
@@ -2015,15 +2086,16 @@ function get_attachment_taxonomies($attachment) {
 }
 
 /**
- * Return all of the taxonomy names that are registered for attachments.
+ * Retrieves all of the taxonomy names that are registered for attachments.
  *
  * Handles mime-type-specific taxonomies such as attachment:image and attachment:video.
  *
  * @since 3.5.0
- * @see get_attachment_taxonomies()
- * @uses get_taxonomies()
  *
- * @param string $output The type of output to return, either taxonomy 'names' or 'objects'. 'names' is the default.
+ * @see get_taxonomies()
+ *
+ * @param string $output Optional. The type of taxonomy output to return. Accepts 'names' or 'objects'.
+ *                       Default 'names'.
  * @return array The names of all taxonomy of $object_type.
  */
 function get_taxonomies_for_attachments( $output = 'names' ) {
@@ -2045,13 +2117,14 @@ function get_taxonomies_for_attachments( $output = 'names' ) {
 
 /**
  * Create new GD image resource with transparency support
- * @TODO: Deprecate if possible.
+ *
+ * @todo: Deprecate if possible.
  *
  * @since 2.9.0
  *
- * @param int $width Image width
- * @param int $height Image height
- * @return image resource
+ * @param int $width  Image width in pixels.
+ * @param int $height Image height in pixels..
+ * @return resource The GD image resource.
  */
 function wp_imagecreatetruecolor($width, $height) {
 	$img = imagecreatetruecolor($width, $height);
@@ -2063,10 +2136,19 @@ function wp_imagecreatetruecolor($width, $height) {
 }
 
 /**
- * Register an embed handler. This function should probably only be used for sites that do not support oEmbed.
+ * Registers an embed handler.
+ *
+ * Should probably only be used for sites that do not support oEmbed.
  *
  * @since 2.9.0
- * @see WP_Embed::register_handler()
+ *
+ * @global WP_Embed $wp_embed
+ *
+ * @param string   $id       An internal ID/name for the handler. Needs to be unique.
+ * @param string   $regex    The regex that will be used to see if this handler should be used for a URL.
+ * @param callback $callback The callback function that will be called if the regex is matched.
+ * @param int      $priority Optional. Used to specify the order in which the registered handlers will
+ *                           be tested. Default 10.
  */
 function wp_embed_register_handler( $id, $regex, $callback, $priority = 10 ) {
 	global $wp_embed;
@@ -2074,10 +2156,14 @@ function wp_embed_register_handler( $id, $regex, $callback, $priority = 10 ) {
 }
 
 /**
- * Unregister a previously registered embed handler.
+ * Unregisters a previously-registered embed handler.
  *
  * @since 2.9.0
- * @see WP_Embed::unregister_handler()
+ *
+ * @global WP_Embed $wp_embed
+ *
+ * @param string $id       The handler ID that should be removed.
+ * @param int    $priority Optional. The priority of the handler to be removed. Default 10.
  */
 function wp_embed_unregister_handler( $id, $priority = 10 ) {
 	global $wp_embed;
@@ -2096,6 +2182,8 @@ function wp_embed_unregister_handler( $id, $priority = 10 ) {
  *
  * @since 2.9.0
  *
+ * @global int $content_width
+ *
  * @param string $url Optional. The URL that should be embedded. Default empty.
  *
  * @return array Default embed parameters.
@@ -2125,12 +2213,13 @@ function wp_embed_defaults( $url = '' ) {
  * Based on a supplied width/height example, return the biggest possible dimensions based on the max width/height.
  *
  * @since 2.9.0
- * @uses wp_constrain_dimensions() This function passes the widths and the heights.
  *
- * @param int $example_width The width of an example embed.
+ * @see wp_constrain_dimensions()
+ *
+ * @param int $example_width  The width of an example embed.
  * @param int $example_height The height of an example embed.
- * @param int $max_width The maximum allowed width.
- * @param int $max_height The maximum allowed height.
+ * @param int $max_width      The maximum allowed width.
+ * @param int $max_height     The maximum allowed height.
  * @return array The maximum possible width and height based on the example ratio.
  */
 function wp_expand_dimensions( $example_width, $example_height, $max_width, $max_height ) {
@@ -2146,14 +2235,13 @@ function wp_expand_dimensions( $example_width, $example_height, $max_width, $max
  * Attempts to fetch the embed HTML for a provided URL using oEmbed.
  *
  * @since 2.9.0
- * @see WP_oEmbed
  *
- * @uses _wp_oembed_get_object()
- * @uses WP_oEmbed::get_html()
+ * @see WP_oEmbed
  *
- * @param string $url The URL that should be embedded.
- * @param array $args Additional arguments and parameters.
- * @return bool|string False on failure or the embed HTML on success.
+ * @param string $url  The URL that should be embedded.
+ * @param array  $args Optional. Additional arguments and parameters for retrieving embed HTML.
+ *                     Default empty.
+ * @return false|string False on failure or the embed HTML on success.
  */
 function wp_oembed_get( $url, $args = '' ) {
 	require_once( ABSPATH . WPINC . '/class-oembed.php' );
@@ -2165,13 +2253,13 @@ function wp_oembed_get( $url, $args = '' ) {
  * Adds a URL format and oEmbed provider URL pair.
  *
  * @since 2.9.0
- * @see WP_oEmbed
  *
- * @uses _wp_oembed_get_object()
+ * @see WP_oEmbed
  *
- * @param string $format The format of URL that this provider can handle. You can use asterisks as wildcards.
- * @param string $provider The URL to the oEmbed provider.
- * @param boolean $regex Whether the $format parameter is in a regex format.
+ * @param string  $format   The format of URL that this provider can handle. You can use asterisks
+ *                          as wildcards.
+ * @param string  $provider The URL to the oEmbed provider.
+ * @param boolean $regex    Optional. Whether the `$format` parameter is in a RegEx format. Default false.
  */
 function wp_oembed_add_provider( $format, $provider, $regex = false ) {
 	require_once( ABSPATH . WPINC . '/class-oembed.php' );
@@ -2188,11 +2276,11 @@ function wp_oembed_add_provider( $format, $provider, $regex = false ) {
  * Removes an oEmbed provider.
  *
  * @since 3.5.0
- * @see WP_oEmbed
  *
- * @uses _wp_oembed_get_object()
+ * @see WP_oEmbed
  *
  * @param string $format The URL format for the oEmbed provider to remove.
+ * @return bool Was the provider removed successfully?
  */
 function wp_oembed_remove_provider( $format ) {
 	require_once( ABSPATH . WPINC . '/class-oembed.php' );
@@ -2218,6 +2306,8 @@ function wp_oembed_remove_provider( $format ) {
  * it hasn't, then it will load the embeds library.
  *
  * @since 2.9.0
+ *
+ * @see wp_embed_register_handler()
  */
 function wp_maybe_load_embeds() {
 	/**
@@ -2233,7 +2323,7 @@ function wp_maybe_load_embeds() {
 		return;
 	}
 
-	wp_embed_register_handler( 'youtube_embed_url', '#https?://(www.)?youtube\.com/embed/([^/]+)#i', 'wp_embed_handler_youtube' );
+	wp_embed_register_handler( 'youtube_embed_url', '#https?://(www.)?youtube\.com/(?:v|embed)/([^/]+)#i', 'wp_embed_handler_youtube' );
 
 	wp_embed_register_handler( 'googlevideo', '#http://video\.google\.([A-Za-z.]{2,5})/videoplay\?docid=([\d-]+)(.*?)#i', 'wp_embed_handler_googlevideo' );
 
@@ -2257,15 +2347,17 @@ function wp_maybe_load_embeds() {
 }
 
 /**
- * The Google Video embed handler callback. Google Video does not support oEmbed.
+ * The Google Video embed handler callback.
+ *
+ * Google Video does not support oEmbed.
  *
  * @see WP_Embed::register_handler()
  * @see WP_Embed::shortcode()
  *
- * @param array $matches The regex matches from the provided regex when calling {@link wp_embed_register_handler()}.
- * @param array $attr Embed attributes.
- * @param string $url The original URL that was matched by the regex.
- * @param array $rawattr The original unmodified attributes.
+ * @param array  $matches The RegEx matches from the provided regex when calling wp_embed_register_handler().
+ * @param array  $attr    Embed attributes.
+ * @param string $url     The original URL that was matched by the regex.
+ * @param array  $rawattr The original unmodified attributes.
  * @return string The embed HTML.
  */
 function wp_embed_handler_googlevideo( $matches, $attr, $url, $rawattr ) {
@@ -2283,7 +2375,7 @@ function wp_embed_handler_googlevideo( $matches, $attr, $url, $rawattr ) {
 	 * @since 2.9.0
 	 *
 	 * @param string $html    Google Video HTML embed markup.
-	 * @param array  $matches The regex matches from the provided regex.
+	 * @param array  $matches The RegEx matches from the provided regex.
 	 * @param array  $attr    An array of embed attributes.
 	 * @param string $url     The original URL that was matched by the regex.
 	 * @param array  $rawattr The original unmodified attributes.
@@ -2292,14 +2384,16 @@ function wp_embed_handler_googlevideo( $matches, $attr, $url, $rawattr ) {
 }
 
 /**
- * YouTube embed handler callback.
+ * YouTube iframe embed handler callback.
  *
- * Catches URLs that can be parsed but aren't supported by oEmbed.
+ * Catches YouTube iframe embed URLs that are not parsable by oEmbed but can be translated into a URL that is.
  *
  * @since 4.0.0
  *
- * @param array  $matches The regex matches from the provided regex when calling
- *                        {@see wp_embed_register_handler()}.
+ * @global WP_Embed $wp_embed
+ *
+ * @param array  $matches The RegEx matches from the provided regex when calling
+ *                        wp_embed_register_handler().
  * @param array  $attr    Embed attributes.
  * @param string $url     The original URL that was matched by the regex.
  * @param array  $rawattr The original unmodified attributes.
@@ -2308,6 +2402,7 @@ function wp_embed_handler_googlevideo( $matches, $attr, $url, $rawattr ) {
 function wp_embed_handler_youtube( $matches, $attr, $url, $rawattr ) {
 	global $wp_embed;
 	$embed = $wp_embed->autoembed( "https://youtube.com/watch?v={$matches[2]}" );
+
 	/**
 	 * Filter the YoutTube embed output.
 	 *
@@ -2328,10 +2423,10 @@ function wp_embed_handler_youtube( $matches, $attr, $url, $rawattr ) {
  *
  * @since 3.6.0
  *
- * @param array $matches The regex matches from the provided regex when calling {@link wp_embed_register_handler()}.
- * @param array $attr Embed attributes.
+ * @param array  $matches The RegEx matches from the provided regex when calling wp_embed_register_handler().
+ * @param array  $attr Embed attributes.
  * @param string $url The original URL that was matched by the regex.
- * @param array $rawattr The original unmodified attributes.
+ * @param array  $rawattr The original unmodified attributes.
  * @return string The embed HTML.
  */
 function wp_embed_handler_audio( $matches, $attr, $url, $rawattr ) {
@@ -2355,10 +2450,10 @@ function wp_embed_handler_audio( $matches, $attr, $url, $rawattr ) {
  *
  * @since 3.6.0
  *
- * @param array $matches The regex matches from the provided regex when calling {@link wp_embed_register_handler()}.
- * @param array $attr Embed attributes.
- * @param string $url The original URL that was matched by the regex.
- * @param array $rawattr The original unmodified attributes.
+ * @param array  $matches The RegEx matches from the provided regex when calling wp_embed_register_handler().
+ * @param array  $attr    Embed attributes.
+ * @param string $url     The original URL that was matched by the regex.
+ * @param array  $rawattr The original unmodified attributes.
  * @return string The embed HTML.
  */
 function wp_embed_handler_video( $matches, $attr, $url, $rawattr ) {
@@ -2403,7 +2498,7 @@ function wp_convert_hr_to_bytes( $size ) {
 }
 
 /**
- * Determine the maximum upload size allowed in php.ini.
+ * Determines the maximum upload size allowed in php.ini.
  *
  * @since 2.5.0
  *
@@ -2429,11 +2524,12 @@ function wp_max_upload_size() {
  * Returns a WP_Image_Editor instance and loads file into it.
  *
  * @since 3.5.0
- * @access public
  *
- * @param string $path Path to file to load
- * @param array $args Additional data. Accepts { 'mime_type'=>string, 'methods'=>{string, string, ...} }
- * @return WP_Image_Editor|WP_Error
+ * @param string $path Path to the file to load.
+ * @param array  $args Optional. Additional arguments for retrieving the image editor.
+ *                     Default empty array.
+ * @return WP_Image_Editor|WP_Error The WP_Image_Editor object if successful, an WP_Error
+ *                                  object otherwise.
  */
 function wp_get_image_editor( $path, $args = array() ) {
 	$args['path'] = $path;
@@ -2466,10 +2562,10 @@ function wp_get_image_editor( $path, $args = array() ) {
  * Tests whether there is an editor that supports a given mime type or methods.
  *
  * @since 3.5.0
- * @access public
  *
- * @param string|array $args Array of requirements. Accepts { 'mime_type'=>string, 'methods'=>{string, string, ...} }
- * @return boolean true if an eligible editor is found; false otherwise
+ * @param string|array $args Optional. Array of arguments to retrieve the image editor supports.
+ *                           Default empty array.
+ * @return bool True if an eligible editor is found; false otherwise.
  */
 function wp_image_editor_supports( $args = array() ) {
 	return (bool) _wp_image_editor_choose( $args );
@@ -2478,11 +2574,12 @@ function wp_image_editor_supports( $args = array() ) {
 /**
  * Tests which editors are capable of supporting the request.
  *
+ * @ignore
  * @since 3.5.0
- * @access private
  *
- * @param array $args Additional data. Accepts { 'mime_type'=>string, 'methods'=>{string, string, ...} }
- * @return string|bool Class name for the first editor that claims to support the request. False if no editor claims to support the request.
+ * @param array $args Optional. Array of arguments for choosing a capable editor. Default empty array.
+ * @return string|false Class name for the first editor that claims to support the request. False if no
+ *                     editor claims to support the request.
  */
 function _wp_image_editor_choose( $args = array() ) {
 	require_once ABSPATH . WPINC . '/class-wp-image-editor.php';
@@ -2527,7 +2624,7 @@ function _wp_image_editor_choose( $args = array() ) {
  * @since 3.4.0
  */
 function wp_plupload_default_settings() {
-	global $wp_scripts;
+	$wp_scripts = wp_scripts();
 
 	$data = $wp_scripts->get_data( 'wp-plupload', 'data' );
 	if ( $data && false !== strpos( $data, '_wpPluploadSettings' ) )
@@ -2546,6 +2643,14 @@ function wp_plupload_default_settings() {
 		),
 	);
 
+	// Currently only iOS Safari supports multiple files uploading but iOS 7.x has a bug that prevents uploading of videos
+	// when enabled. See #29602.
+	if ( wp_is_mobile() && strpos( $_SERVER['HTTP_USER_AGENT'], 'OS 7_' ) !== false &&
+		strpos( $_SERVER['HTTP_USER_AGENT'], 'like Mac OS X' ) !== false ) {
+
+		$defaults['multi_selection'] = false;
+	}
+
 	/**
 	 * Filter the Plupload default settings.
 	 *
@@ -2579,14 +2684,13 @@ function wp_plupload_default_settings() {
 		'limitExceeded' => is_multisite() && ! is_upload_space_available()
 	);
 
-	$script = 'var _wpPluploadSettings = ' . json_encode( $settings ) . ';';
+	$script = 'var _wpPluploadSettings = ' . wp_json_encode( $settings ) . ';';
 
 	if ( $data )
 		$script = "$data\n$script";
 
 	$wp_scripts->add_data( 'wp-plupload', 'data', $script );
 }
-add_action( 'customize_controls_enqueue_scripts', 'wp_plupload_default_settings' );
 
 /**
  * Prepares an attachment post object for JS, where it is expected
@@ -2595,7 +2699,7 @@ add_action( 'customize_controls_enqueue_scripts', 'wp_plupload_default_settings'
  * @since 3.5.0
  *
  * @param mixed $attachment Attachment ID or object.
- * @return array Array of attachment details.
+ * @return array|void Array of attachment details.
  */
 function wp_prepare_attachment_for_js( $attachment ) {
 	if ( ! $attachment = get_post( $attachment ) )
@@ -2615,7 +2719,7 @@ function wp_prepare_attachment_for_js( $attachment ) {
 	$response = array(
 		'id'          => $attachment->ID,
 		'title'       => $attachment->post_title,
-		'filename'    => wp_basename( $attachment->guid ),
+		'filename'    => wp_basename( get_attached_file( $attachment->ID ) ),
 		'url'         => $attachment_url,
 		'link'        => get_attachment_link( $attachment->ID ),
 		'alt'         => get_post_meta( $attachment->ID, '_wp_attachment_image_alt', true ),
@@ -2787,9 +2891,18 @@ function wp_prepare_attachment_for_js( $attachment ) {
  * all media JS APIs.
  *
  * @since 3.5.0
+ *
+ * @global int       $content_width
+ * @global wpdb      $wpdb
+ * @global WP_Locale $wp_locale
+ *
+ * @param array $args {
+ *     Arguments for enqueuing media scripts.
+ *
+ *     @type int|WP_Post A post object or ID.
+ * }
  */
 function wp_enqueue_media( $args = array() ) {
-
 	// Enqueue me just once per page, please.
 	if ( did_action( 'wp_enqueue_media' ) )
 		return;
@@ -2891,9 +3004,9 @@ function wp_enqueue_media( $args = array() ) {
 
 		$thumbnail_support = current_theme_supports( 'post-thumbnails', $post->post_type ) && post_type_supports( $post->post_type, 'thumbnail' );
 		if ( ! $thumbnail_support && 'attachment' === $post->post_type && $post->post_mime_type ) {
-			if ( 0 === strpos( $post->post_mime_type, 'audio/' ) ) {
+			if ( wp_attachment_is( 'audio', $post ) ) {
 				$thumbnail_support = post_type_supports( 'attachment:audio', 'thumbnail' ) || current_theme_supports( 'post-thumbnails', 'attachment:audio' );
-			} elseif ( 0 === strpos( $post->post_mime_type, 'video/' ) ) {
+			} elseif ( wp_attachment_is( 'video', $post ) ) {
 				$thumbnail_support = post_type_supports( 'attachment:video', 'thumbnail' ) || current_theme_supports( 'post-thumbnails', 'attachment:video' );
 			}
 		}
@@ -2906,6 +3019,12 @@ function wp_enqueue_media( $args = array() ) {
 
 	$hier = $post && is_post_type_hierarchical( $post->post_type );
 
+	if ( $post ) {
+		$post_type_object = get_post_type_object( $post->post_type );
+	} else {
+		$post_type_object = get_post_type_object( 'post' );
+	}
+
 	$strings = array(
 		// Generic
 		'url'         => __( 'URL' ),
@@ -2922,7 +3041,7 @@ function wp_enqueue_media( $args = array() ) {
 		   lack of plural support here, turn it into "selected: %d" then translate it.
 		 */
 		'selected'    => __( '%d selected' ),
-		'dragInfo'    => __( 'Drag and drop to reorder images.' ),
+		'dragInfo'    => __( 'Drag and drop to reorder media files.' ),
 
 		// Upload
 		'uploadFilesTitle'  => __( 'Upload Files' ),
@@ -2936,12 +3055,11 @@ function wp_enqueue_media( $args = array() ) {
 		'createNewVideoPlaylist' => __( 'Create a new video playlist' ),
 		'returnToLibrary'        => __( '&#8592; Return to library' ),
 		'allMediaItems'          => __( 'All media items' ),
-		'allMediaTypes'          => __( 'All media types' ),
 		'allDates'               => __( 'All dates' ),
 		'noItemsFound'           => __( 'No items found.' ),
 		'insertIntoPost'         => $hier ? __( 'Insert into page' ) : __( 'Insert into post' ),
 		'unattached'             => __( 'Unattached' ),
-		'trash'                  => __( 'Trash' ),
+		'trash'                  => _x( 'Trash', 'noun' ),
 		'uploadedToThisPost'     => $hier ? __( 'Uploaded to this page' ) : __( 'Uploaded to this post' ),
 		'warnDelete'             => __( "You are about to permanently delete this item.\n  'Cancel' to stop, 'OK' to delete." ),
 		'warnBulkDelete'         => __( "You are about to permanently delete these items.\n  'Cancel' to stop, 'OK' to delete." ),
@@ -2956,6 +3074,7 @@ function wp_enqueue_media( $args = array() ) {
 		'filterByDate'           => __( 'Filter by date' ),
 		'filterByType'           => __( 'Filter by type' ),
 		'searchMediaLabel'       => __( 'Search Media' ),
+		'noMedia'                => __( 'No media attachments found.' ),
 
 		// Library Details
 		'attachmentDetails'  => __( 'Attachment Details' ),
@@ -2964,8 +3083,8 @@ function wp_enqueue_media( $args = array() ) {
 		'insertFromUrlTitle' => __( 'Insert from URL' ),
 
 		// Featured Images
-		'setFeaturedImageTitle' => __( 'Set Featured Image' ),
-		'setFeaturedImage'    => __( 'Set featured image' ),
+		'setFeaturedImageTitle' => $post_type_object->labels->featured_image,
+		'setFeaturedImage'      => $post_type_object->labels->set_featured_image,
 
 		// Gallery
 		'createGalleryTitle' => __( 'Create Gallery' ),
@@ -3026,10 +3145,6 @@ function wp_enqueue_media( $args = array() ) {
  		'updateVideoPlaylist'      => __( 'Update video playlist' ),
  		'addToVideoPlaylist'       => __( 'Add to video playlist' ),
  		'addToVideoPlaylistTitle'  => __( 'Add to Video Playlist' ),
-
- 		// Media Library
- 		'editMetadata' => __( 'Edit Metadata' ),
- 		'noMedia'      => __( 'No media attachments found.' ),
 	);
 
 	/**
@@ -3082,7 +3197,7 @@ function wp_enqueue_media( $args = array() ) {
 }
 
 /**
- * Retrieve media attached to the passed post.
+ * Retrieves media attached to the passed post.
  *
  * @since 3.6.0
  *
@@ -3129,26 +3244,40 @@ function get_attached_media( $type, $post = 0 ) {
 }
 
 /**
- * Check the content blob for an <audio>, <video> <object>, <embed>, or <iframe>
+ * Check the content blob for an audio, video, object, embed, or iframe tags.
  *
  * @since 3.6.0
  *
  * @param string $content A string which might contain media data.
- * @param array $types array of media types: 'audio', 'video', 'object', 'embed', or 'iframe'
- * @return array A list of found HTML media embeds
+ * @param array  $types   An array of media types: 'audio', 'video', 'object', 'embed', or 'iframe'.
+ * @return array A list of found HTML media embeds.
  */
 function get_media_embedded_in_content( $content, $types = null ) {
 	$html = array();
-	$allowed_media_types = array( 'audio', 'video', 'object', 'embed', 'iframe' );
+
+	/**
+	 * Filter the embedded media types that are allowed to be returned from the content blob.
+	 *
+	 * @since 4.2.0
+	 *
+	 * @param array $allowed_media_types An array of allowed media types. Default media types are
+	 *                                   'audio', 'video', 'object', 'embed', and 'iframe'.
+	 */
+	$allowed_media_types = apply_filters( 'media_embedded_in_content_allowed_types', array( 'audio', 'video', 'object', 'embed', 'iframe' ) );
+
 	if ( ! empty( $types ) ) {
-		if ( ! is_array( $types ) )
+		if ( ! is_array( $types ) ) {
 			$types = array( $types );
+		}
+
 		$allowed_media_types = array_intersect( $allowed_media_types, $types );
 	}
 
-	foreach ( $allowed_media_types as $tag ) {
-		if ( preg_match( '#' . get_tag_regex( $tag ) . '#', $content, $matches ) ) {
-			$html[] = $matches[0];
+	$tags = implode( '|', $allowed_media_types );
+
+	if ( preg_match_all( '#<(?P<tag>' . $tags . ')[^<]*?(?:>[\s\S]*?<\/(?P=tag)>|\s*\/>)#', $content, $matches ) ) {
+		foreach ( $matches[0] as $match ) {
+			$html[] = $match;
 		}
 	}
 
@@ -3156,14 +3285,14 @@ function get_media_embedded_in_content( $content, $types = null ) {
 }
 
 /**
- * Retrieve galleries from the passed post's content.
+ * Retrieves galleries from the passed post's content.
  *
  * @since 3.6.0
  *
- * @param int|WP_Post $post Optional. Post ID or object.
- * @param bool        $html Whether to return HTML or data in the array.
+ * @param int|WP_Post $post Post ID or object.
+ * @param bool        $html Optional. Whether to return HTML or data in the array. Default true.
  * @return array A list of arrays, each containing gallery data and srcs parsed
- *		         from the expanded shortcode.
+ *               from the expanded shortcode.
  */
 function get_post_galleries( $post, $html = true ) {
 	if ( ! $post = get_post( $post ) )
@@ -3213,7 +3342,7 @@ function get_post_galleries( $post, $html = true ) {
  * @since 3.6.0
  *
  * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
- * @param bool        $html Whether to return HTML or data.
+ * @param bool        $html Optional. Whether to return HTML or data. Default is true.
  * @return string|array Gallery data and srcs parsed from the expanded shortcode.
  */
 function get_post_gallery( $post = 0, $html = true ) {
@@ -3237,9 +3366,11 @@ function get_post_gallery( $post = 0, $html = true ) {
  *
  * @since 3.6.0
  *
- * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
+ * @see get_post_galleries()
+ *
+ * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
  * @return array A list of lists, each containing image srcs parsed.
- *		from an expanded shortcode
+ *               from an expanded shortcode
  */
 function get_post_galleries_images( $post = 0 ) {
 	$galleries = get_post_galleries( $post, false );
@@ -3247,11 +3378,13 @@ function get_post_galleries_images( $post = 0 ) {
 }
 
 /**
- * Check a post's content for galleries and return the image srcs for the first found gallery
+ * Checks a post's content for galleries and return the image srcs for the first found gallery
  *
  * @since 3.6.0
  *
- * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global $post.
+ * @see get_post_gallery()
+ *
+ * @param int|WP_Post $post Optional. Post ID or WP_Post object. Default is global `$post`.
  * @return array A list of a gallery's image srcs in order.
  */
 function get_post_gallery_images( $post = 0 ) {
@@ -3260,7 +3393,7 @@ function get_post_gallery_images( $post = 0 ) {
 }
 
 /**
- * Maybe attempt to generate attachment metadata, if missing.
+ * Maybe attempts to generate attachment metadata, if missing.
  *
  * @since 3.9.0
  *
@@ -3285,37 +3418,50 @@ function wp_maybe_generate_attachment_metadata( $attachment ) {
 }
 
 /**
- * Try to convert an attachment URL into a post ID.
+ * Tries to convert an attachment URL into a post ID.
  *
  * @since 4.0.0
  *
- * @global wpdb $wpdb WordPress database access abstraction object.
+ * @global wpdb $wpdb WordPress database abstraction object.
  *
  * @param string $url The URL to resolve.
- * @return int The found post ID.
+ * @return int The found post ID, or 0 on failure.
  */
 function attachment_url_to_postid( $url ) {
 	global $wpdb;
 
 	$dir = wp_upload_dir();
-	$path = ltrim( $url, $dir['baseurl'] . '/' );
+	$path = $url;
+
+	if ( 0 === strpos( $path, $dir['baseurl'] . '/' ) ) {
+		$path = substr( $path, strlen( $dir['baseurl'] . '/' ) );
+	}
 
 	$sql = $wpdb->prepare(
 		"SELECT post_id FROM $wpdb->postmeta WHERE meta_key = '_wp_attached_file' AND meta_value = %s",
 		$path
 	);
 	$post_id = $wpdb->get_var( $sql );
-	if ( ! empty( $post_id ) ) {
-		return (int) $post_id;
-	}
+
+	/**
+	 * Filter an attachment id found by URL.
+	 *
+	 * @since 4.2.0
+	 *
+	 * @param int|null $post_id The post_id (if any) found by the function.
+	 * @param string   $url     The URL being looked up.
+	 */
+	$post_id = apply_filters( 'attachment_url_to_postid', $post_id, $url );
+
+	return (int) $post_id;
 }
 
 /**
- * Return the URls for CSS files used in an <iframe>-sandbox'd TinyMCE media view
+ * Returns the URLs for CSS files used in an iframe-sandbox'd TinyMCE media view.
  *
  * @since 4.0.0
  *
- * @global $wp_version
+ * @global string $wp_version
  *
  * @return array The relevant CSS file URLs.
  */