Add upstream

wp-content/plugins/jetpack/modules/carousel/jetpack-carousel.php

@@ -0,0 +1,832 @@
+<?php
+use Automattic\Jetpack\Assets;
+/*
+Plugin Name: Jetpack Carousel
+Plugin URL: https://wordpress.com/
+Description: Transform your standard image galleries into an immersive full-screen experience.
+Version: 0.1
+Author: Automattic
+
+Released under the GPL v.2 license.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+*/
+class Jetpack_Carousel {
+
+	public $prebuilt_widths = array( 370, 700, 1000, 1200, 1400, 2000 );
+
+	public $first_run = true;
+
+	public $in_gallery = false;
+
+	public $in_jetpack = true;
+
+	public $single_image_gallery_enabled = false;
+
+	public $single_image_gallery_enabled_media_file = false;
+
+	function __construct() {
+		add_action( 'init', array( $this, 'init' ) );
+	}
+
+	function init() {
+		if ( $this->maybe_disable_jp_carousel() ) {
+			return;
+		}
+
+		$this->in_jetpack = ( class_exists( 'Jetpack' ) && method_exists( 'Jetpack', 'enable_module_configurable' ) ) ? true : false;
+
+		$this->single_image_gallery_enabled            = ! $this->maybe_disable_jp_carousel_single_images();
+		$this->single_image_gallery_enabled_media_file = $this->maybe_enable_jp_carousel_single_images_media_file();
+
+		if ( is_admin() ) {
+			// Register the Carousel-related related settings
+			add_action( 'admin_init', array( $this, 'register_settings' ), 5 );
+			if ( ! $this->in_jetpack ) {
+				if ( 0 == $this->test_1or0_option( get_option( 'carousel_enable_it' ), true ) ) {
+					return; // Carousel disabled, abort early, but still register setting so user can switch it back on
+				}
+			}
+			// If in admin, register the ajax endpoints.
+			add_action( 'wp_ajax_get_attachment_comments', array( $this, 'get_attachment_comments' ) );
+			add_action( 'wp_ajax_nopriv_get_attachment_comments', array( $this, 'get_attachment_comments' ) );
+			add_action( 'wp_ajax_post_attachment_comment', array( $this, 'post_attachment_comment' ) );
+			add_action( 'wp_ajax_nopriv_post_attachment_comment', array( $this, 'post_attachment_comment' ) );
+		} else {
+			if ( ! $this->in_jetpack ) {
+				if ( 0 == $this->test_1or0_option( get_option( 'carousel_enable_it' ), true ) ) {
+					return; // Carousel disabled, abort early
+				}
+			}
+			// If on front-end, do the Carousel thang.
+			/**
+			 * Filter the array of default prebuilt widths used in Carousel.
+			 *
+			 * @module carousel
+			 *
+			 * @since 1.6.0
+			 *
+			 * @param array $this->prebuilt_widths Array of default widths.
+			 */
+			$this->prebuilt_widths = apply_filters( 'jp_carousel_widths', $this->prebuilt_widths );
+			// below: load later than other callbacks hooked it (e.g. 3rd party plugins handling gallery shortcode)
+			add_filter( 'post_gallery', array( $this, 'check_if_shortcode_processed_and_enqueue_assets' ), 1000, 2 );
+			add_filter( 'post_gallery', array( $this, 'set_in_gallery' ), -1000 );
+			add_filter( 'gallery_style', array( $this, 'add_data_to_container' ) );
+			add_filter( 'wp_get_attachment_image_attributes', array( $this, 'add_data_to_images' ), 10, 2 );
+			add_filter( 'the_content', array( $this, 'check_content_for_blocks' ), 1 );
+			add_filter( 'jetpack_tiled_galleries_block_content', array( $this, 'add_data_img_tags_and_enqueue_assets' ) );
+			if ( $this->single_image_gallery_enabled ) {
+				add_filter( 'the_content', array( $this, 'add_data_img_tags_and_enqueue_assets' ) );
+			}
+		}
+
+		if ( $this->in_jetpack ) {
+			Jetpack::enable_module_configurable( dirname( dirname( __FILE__ ) ) . '/carousel.php' );
+		}
+	}
+
+	function maybe_disable_jp_carousel() {
+		/**
+		 * Allow third-party plugins or themes to disable Carousel.
+		 *
+		 * @module carousel
+		 *
+		 * @since 1.6.0
+		 *
+		 * @param bool false Should Carousel be disabled? Default to false.
+		 */
+		return apply_filters( 'jp_carousel_maybe_disable', false );
+	}
+
+	function maybe_disable_jp_carousel_single_images() {
+		/**
+		 * Allow third-party plugins or themes to disable Carousel for single images.
+		 *
+		 * @module carousel
+		 *
+		 * @since 4.5.0
+		 *
+		 * @param bool false Should Carousel be disabled for single images? Default to false.
+		 */
+		return apply_filters( 'jp_carousel_maybe_disable_single_images', false );
+	}
+
+	function maybe_enable_jp_carousel_single_images_media_file() {
+		/**
+		 * Allow third-party plugins or themes to enable Carousel
+		 * for single images linking to 'Media File' (full size image).
+		 *
+		 * @module carousel
+		 *
+		 * @since 4.5.0
+		 *
+		 * @param bool false Should Carousel be enabled for single images linking to 'Media File'? Default to false.
+		 */
+		return apply_filters( 'jp_carousel_load_for_images_linked_to_file', false );
+	}
+
+	function asset_version( $version ) {
+		/**
+		 * Filter the version string used when enqueuing Carousel assets.
+		 *
+		 * @module carousel
+		 *
+		 * @since 1.6.0
+		 *
+		 * @param string $version Asset version.
+		 */
+		return apply_filters( 'jp_carousel_asset_version', $version );
+	}
+
+	function display_bail_message( $output = '' ) {
+		// Displays a message on top of gallery if carousel has bailed
+		$message  = '<div class="jp-carousel-msg"><p>';
+		$message .= __( 'Jetpack\'s Carousel has been disabled, because another plugin or your theme is overriding the [gallery] shortcode.', 'jetpack' );
+		$message .= '</p></div>';
+		// put before gallery output
+		$output = $message . $output;
+		return $output;
+	}
+
+	function check_if_shortcode_processed_and_enqueue_assets( $output ) {
+		if (
+			class_exists( 'Jetpack_AMP_Support' )
+			&& Jetpack_AMP_Support::is_amp_request()
+		) {
+			return $output;
+		}
+
+		if (
+			! empty( $output ) &&
+			/**
+			 * Allow third-party plugins or themes to force-enable Carousel.
+			 *
+			 * @module carousel
+			 *
+			 * @since 1.9.0
+			 *
+			 * @param bool false Should we force enable Carousel? Default to false.
+			 */
+			! apply_filters( 'jp_carousel_force_enable', false )
+		) {
+			// Bail because someone is overriding the [gallery] shortcode.
+			remove_filter( 'gallery_style', array( $this, 'add_data_to_container' ) );
+			remove_filter( 'wp_get_attachment_image_attributes', array( $this, 'add_data_to_images' ) );
+			remove_filter( 'the_content', array( $this, 'add_data_img_tags_and_enqueue_assets' ) );
+			// Display message that carousel has bailed, if user is super_admin, and if we're not on WordPress.com.
+			if (
+				is_super_admin() &&
+				! ( defined( 'IS_WPCOM' ) && IS_WPCOM )
+			) {
+				add_filter( 'post_gallery', array( $this, 'display_bail_message' ) );
+			}
+			return $output;
+		}
+
+		/**
+		 * Fires when thumbnails are shown in Carousel.
+		 *
+		 * @module carousel
+		 *
+		 * @since 1.6.0
+		 **/
+		do_action( 'jp_carousel_thumbnails_shown' );
+
+		$this->enqueue_assets();
+
+		return $output;
+	}
+
+	/**
+	 * Check if the content of a post uses gallery blocks. To be used by 'the_content' filter.
+	 *
+	 * @since 6.8.0
+	 *
+	 * @param string $content Post content.
+	 *
+	 * @return string $content Post content.
+	 */
+	function check_content_for_blocks( $content ) {
+		if (
+			class_exists( 'Jetpack_AMP_Support' )
+			&& Jetpack_AMP_Support::is_amp_request()
+		) {
+			return $content;
+		}
+
+		if ( has_block( 'gallery', $content ) || has_block( 'jetpack/tiled-gallery', $content ) ) {
+			$this->enqueue_assets();
+			$content = $this->add_data_to_container( $content );
+		}
+		return $content;
+	}
+
+	function enqueue_assets() {
+		if ( $this->first_run ) {
+			wp_enqueue_script(
+				'jetpack-carousel',
+				Assets::get_file_url_for_environment(
+					'_inc/build/carousel/jetpack-carousel.min.js',
+					'modules/carousel/jetpack-carousel.js'
+				),
+				array( 'jquery.spin' ),
+				$this->asset_version( '20190102' ),
+				true
+			);
+
+			// Note: using  home_url() instead of admin_url() for ajaxurl to be sure  to get same domain on wpcom when using mapped domains (also works on self-hosted)
+			// Also: not hardcoding path since there is no guarantee site is running on site root in self-hosted context.
+			$is_logged_in         = is_user_logged_in();
+			$current_user         = wp_get_current_user();
+			$comment_registration = intval( get_option( 'comment_registration' ) );
+			$require_name_email   = intval( get_option( 'require_name_email' ) );
+			$localize_strings     = array(
+				'widths'                          => $this->prebuilt_widths,
+				'is_logged_in'                    => $is_logged_in,
+				'lang'                            => strtolower( substr( get_locale(), 0, 2 ) ),
+				'ajaxurl'                         => set_url_scheme( admin_url( 'admin-ajax.php' ) ),
+				'nonce'                           => wp_create_nonce( 'carousel_nonce' ),
+				'display_exif'                    => $this->test_1or0_option( Jetpack_Options::get_option_and_ensure_autoload( 'carousel_display_exif', true ) ),
+				'display_geo'                     => $this->test_1or0_option( Jetpack_Options::get_option_and_ensure_autoload( 'carousel_display_geo', true ) ),
+				'single_image_gallery'            => $this->single_image_gallery_enabled,
+				'single_image_gallery_media_file' => $this->single_image_gallery_enabled_media_file,
+				'background_color'                => $this->carousel_background_color_sanitize( Jetpack_Options::get_option_and_ensure_autoload( 'carousel_background_color', '' ) ),
+				'comment'                         => __( 'Comment', 'jetpack' ),
+				'post_comment'                    => __( 'Post Comment', 'jetpack' ),
+				'write_comment'                   => __( 'Write a Comment...', 'jetpack' ),
+				'loading_comments'                => __( 'Loading Comments...', 'jetpack' ),
+				'download_original'               => sprintf( __( 'View full size <span class="photo-size">%1$s<span class="photo-size-times">&times;</span>%2$s</span>', 'jetpack' ), '{0}', '{1}' ),
+				'no_comment_text'                 => __( 'Please be sure to submit some text with your comment.', 'jetpack' ),
+				'no_comment_email'                => __( 'Please provide an email address to comment.', 'jetpack' ),
+				'no_comment_author'               => __( 'Please provide your name to comment.', 'jetpack' ),
+				'comment_post_error'              => __( 'Sorry, but there was an error posting your comment. Please try again later.', 'jetpack' ),
+				'comment_approved'                => __( 'Your comment was approved.', 'jetpack' ),
+				'comment_unapproved'              => __( 'Your comment is in moderation.', 'jetpack' ),
+				'camera'                          => __( 'Camera', 'jetpack' ),
+				'aperture'                        => __( 'Aperture', 'jetpack' ),
+				'shutter_speed'                   => __( 'Shutter Speed', 'jetpack' ),
+				'focal_length'                    => __( 'Focal Length', 'jetpack' ),
+				'copyright'                       => __( 'Copyright', 'jetpack' ),
+				'comment_registration'            => $comment_registration,
+				'require_name_email'              => $require_name_email,
+				/** This action is documented in core/src/wp-includes/link-template.php */
+				'login_url'                       => wp_login_url( apply_filters( 'the_permalink', get_permalink() ) ),
+				'blog_id'                         => (int) get_current_blog_id(),
+				'meta_data'                       => array( 'camera', 'aperture', 'shutter_speed', 'focal_length', 'copyright' ),
+			);
+
+			if ( ! isset( $localize_strings['jetpack_comments_iframe_src'] ) || empty( $localize_strings['jetpack_comments_iframe_src'] ) ) {
+				// We're not using Comments after all, so fallback to standard local comments.
+
+				if ( $is_logged_in ) {
+					$localize_strings['local_comments_commenting_as'] = '<p id="jp-carousel-commenting-as">' . sprintf( __( 'Commenting as %s', 'jetpack' ), $current_user->data->display_name ) . '</p>';
+				} else {
+					if ( $comment_registration ) {
+						$localize_strings['local_comments_commenting_as'] = '<p id="jp-carousel-commenting-as">' . __( 'You must be <a href="#" class="jp-carousel-comment-login">logged in</a> to post a comment.', 'jetpack' ) . '</p>';
+					} else {
+						$required = ( $require_name_email ) ? __( '%s (Required)', 'jetpack' ) : '%s';
+						$localize_strings['local_comments_commenting_as'] = ''
+							. '<fieldset><label for="email">' . sprintf( $required, __( 'Email', 'jetpack' ) ) . '</label> '
+							. '<input type="text" name="email" class="jp-carousel-comment-form-field jp-carousel-comment-form-text-field" id="jp-carousel-comment-form-email-field" /></fieldset>'
+							. '<fieldset><label for="author">' . sprintf( $required, __( 'Name', 'jetpack' ) ) . '</label> '
+							. '<input type="text" name="author" class="jp-carousel-comment-form-field jp-carousel-comment-form-text-field" id="jp-carousel-comment-form-author-field" /></fieldset>'
+							. '<fieldset><label for="url">' . __( 'Website', 'jetpack' ) . '</label> '
+							. '<input type="text" name="url" class="jp-carousel-comment-form-field jp-carousel-comment-form-text-field" id="jp-carousel-comment-form-url-field" /></fieldset>';
+					}
+				}
+			}
+
+			/**
+			 * Handle WP stats for images in full-screen.
+			 * Build string with tracking info.
+			 */
+
+			/**
+			 * Filter if Jetpack should enable stats collection on carousel views
+			 *
+			 * @module carousel
+			 *
+			 * @since 4.3.2
+			 *
+			 * @param bool Enable Jetpack Carousel stat collection. Default false.
+			 */
+			if ( apply_filters( 'jetpack_enable_carousel_stats', false ) && in_array( 'stats', Jetpack::get_active_modules() ) && ! Jetpack::is_development_mode() ) {
+				$localize_strings['stats'] = 'blog=' . Jetpack_Options::get_option( 'id' ) . '&host=' . parse_url( get_option( 'home' ), PHP_URL_HOST ) . '&v=ext&j=' . JETPACK__API_VERSION . ':' . JETPACK__VERSION;
+
+				// Set the stats as empty if user is logged in but logged-in users shouldn't be tracked.
+				if ( is_user_logged_in() && function_exists( 'stats_get_options' ) ) {
+					$stats_options        = stats_get_options();
+					$track_loggedin_users = isset( $stats_options['reg_users'] ) ? (bool) $stats_options['reg_users'] : false;
+
+					if ( ! $track_loggedin_users ) {
+						$localize_strings['stats'] = '';
+					}
+				}
+			}
+
+			/**
+			 * Filter the strings passed to the Carousel's js file.
+			 *
+			 * @module carousel
+			 *
+			 * @since 1.6.0
+			 *
+			 * @param array $localize_strings Array of strings passed to the Jetpack js file.
+			 */
+			$localize_strings = apply_filters( 'jp_carousel_localize_strings', $localize_strings );
+			wp_localize_script( 'jetpack-carousel', 'jetpackCarouselStrings', $localize_strings );
+			wp_enqueue_style( 'jetpack-carousel', plugins_url( 'jetpack-carousel.css', __FILE__ ), array(), $this->asset_version( '20120629' ) );
+			wp_style_add_data( 'jetpack-carousel', 'rtl', 'replace' );
+
+			/**
+			 * Fires after carousel assets are enqueued for the first time.
+			 * Allows for adding additional assets to the carousel page.
+			 *
+			 * @module carousel
+			 *
+			 * @since 1.6.0
+			 *
+			 * @param bool $first_run First load if Carousel on the page.
+			 * @param array $localized_strings Array of strings passed to the Jetpack js file.
+			 */
+			do_action( 'jp_carousel_enqueue_assets', $this->first_run, $localize_strings );
+
+			$this->first_run = false;
+		}
+	}
+
+	function set_in_gallery( $output ) {
+		if (
+			class_exists( 'Jetpack_AMP_Support' )
+			&& Jetpack_AMP_Support::is_amp_request()
+		) {
+			return $output;
+		}
+		$this->in_gallery = true;
+		return $output;
+	}
+
+	/**
+	 * Adds data-* attributes required by carousel to img tags in post HTML
+	 * content. To be used by 'the_content' filter.
+	 *
+	 * @see add_data_to_images()
+	 * @see wp_make_content_images_responsive() in wp-includes/media.php
+	 *
+	 * @param string $content HTML content of the post
+	 * @return string Modified HTML content of the post
+	 */
+	function add_data_img_tags_and_enqueue_assets( $content ) {
+		if (
+			class_exists( 'Jetpack_AMP_Support' )
+			&& Jetpack_AMP_Support::is_amp_request()
+		) {
+			return $content;
+		}
+
+		if ( ! preg_match_all( '/<img [^>]+>/', $content, $matches ) ) {
+			return $content;
+		}
+		$selected_images = array();
+		foreach ( $matches[0] as $image_html ) {
+			if ( preg_match( '/(wp-image-|data-id=)\"?([0-9]+)\"?/i', $image_html, $class_id ) &&
+				! preg_match( '/wp-block-jetpack-slideshow_image/', $image_html ) ) {
+				$attachment_id = absint( $class_id[2] );
+				/**
+				 * If exactly the same image tag is used more than once, overwrite it.
+				 * All identical tags will be replaced later with 'str_replace()'.
+				 */
+				$selected_images[ $attachment_id  ] = $image_html;
+			}
+		}
+
+		$find    = array();
+		$replace = array();
+		if ( empty( $selected_images ) ) {
+			return $content;
+		}
+
+		$attachments = get_posts(
+			array(
+				'include'          => array_keys( $selected_images ),
+				'post_type'        => 'any',
+				'post_status'      => 'any',
+				'suppress_filters' => false,
+			)
+		);
+
+		foreach ( $attachments as $attachment ) {
+			$image_html = $selected_images[ $attachment->ID ];
+
+			$attributes      = $this->add_data_to_images( array(), $attachment );
+			$attributes_html = '';
+			foreach ( $attributes as $k => $v ) {
+				$attributes_html .= esc_attr( $k ) . '="' . esc_attr( $v ) . '" ';
+			}
+
+			$find[]    = $image_html;
+			$replace[] = str_replace( '<img ', "<img $attributes_html", $image_html );
+		}
+
+		$content = str_replace( $find, $replace, $content );
+		$this->enqueue_assets();
+		return $content;
+	}
+
+	function add_data_to_images( $attr, $attachment = null ) {
+		if (
+			class_exists( 'Jetpack_AMP_Support' )
+			&& Jetpack_AMP_Support::is_amp_request()
+		) {
+			return $attr;
+		}
+
+		$attachment_id = intval( $attachment->ID );
+		if ( ! wp_attachment_is_image( $attachment_id ) ) {
+			return $attr;
+		}
+
+		$orig_file       = wp_get_attachment_image_src( $attachment_id, 'full' );
+		$orig_file       = isset( $orig_file[0] ) ? $orig_file[0] : wp_get_attachment_url( $attachment_id );
+		$meta            = wp_get_attachment_metadata( $attachment_id );
+		$size            = isset( $meta['width'] ) ? intval( $meta['width'] ) . ',' . intval( $meta['height'] ) : '';
+		$img_meta        = ( ! empty( $meta['image_meta'] ) ) ? (array) $meta['image_meta'] : array();
+		$comments_opened = intval( comments_open( $attachment_id ) );
+
+		/**
+		 * Note: Cannot generate a filename from the width and height wp_get_attachment_image_src() returns because
+		 * it takes the $content_width global variable themes can set in consideration, therefore returning sizes
+		 * which when used to generate a filename will likely result in a 404 on the image.
+		 * $content_width has no filter we could temporarily de-register, run wp_get_attachment_image_src(), then
+		 * re-register. So using returned file URL instead, which we can define the sizes from through filename
+		 * parsing in the JS, as this is a failsafe file reference.
+		 *
+		 * EG with Twenty Eleven activated:
+		 * array(4) { [0]=> string(82) "http://vanillawpinstall.blah/wp-content/uploads/2012/06/IMG_3534-1024x764.jpg" [1]=> int(584) [2]=> int(435) [3]=> bool(true) }
+		 *
+		 * EG with Twenty Ten activated:
+		 * array(4) { [0]=> string(82) "http://vanillawpinstall.blah/wp-content/uploads/2012/06/IMG_3534-1024x764.jpg" [1]=> int(640) [2]=> int(477) [3]=> bool(true) }
+		 */
+
+		$medium_file_info = wp_get_attachment_image_src( $attachment_id, 'medium' );
+		$medium_file      = isset( $medium_file_info[0] ) ? $medium_file_info[0] : '';
+
+		$large_file_info = wp_get_attachment_image_src( $attachment_id, 'large' );
+		$large_file      = isset( $large_file_info[0] ) ? $large_file_info[0] : '';
+
+		$attachment       = get_post( $attachment_id );
+		$attachment_title = wptexturize( $attachment->post_title );
+		$attachment_desc  = wpautop( wptexturize( $attachment->post_content ) );
+		// Not yet providing geo-data, need to "fuzzify" for privacy
+		if ( ! empty( $img_meta ) ) {
+			foreach ( $img_meta as $k => $v ) {
+				if ( 'latitude' == $k || 'longitude' == $k ) {
+					unset( $img_meta[ $k ] );
+				}
+			}
+		}
+
+		// See https://github.com/Automattic/jetpack/issues/2765
+		if ( isset( $img_meta['keywords'] ) ) {
+			unset( $img_meta['keywords'] );
+		}
+
+		$img_meta = json_encode( array_map( 'strval', array_filter( $img_meta, 'is_scalar' ) ) );
+
+		$attr['data-attachment-id']     = $attachment_id;
+		$attr['data-permalink']         = esc_attr( get_permalink( $attachment->ID ) );
+		$attr['data-orig-file']         = esc_attr( $orig_file );
+		$attr['data-orig-size']         = $size;
+		$attr['data-comments-opened']   = $comments_opened;
+		$attr['data-image-meta']        = esc_attr( $img_meta );
+		$attr['data-image-title']       = esc_attr( htmlspecialchars( $attachment_title ) );
+		$attr['data-image-description'] = esc_attr( htmlspecialchars( $attachment_desc ) );
+		$attr['data-medium-file']       = esc_attr( $medium_file );
+		$attr['data-large-file']        = esc_attr( $large_file );
+
+		return $attr;
+	}
+
+	function add_data_to_container( $html ) {
+		global $post;
+		if (
+			class_exists( 'Jetpack_AMP_Support' )
+			&& Jetpack_AMP_Support::is_amp_request()
+		) {
+			return $html;
+		}
+
+		if ( isset( $post ) ) {
+			$blog_id = (int) get_current_blog_id();
+
+			$extra_data = array(
+				'data-carousel-extra' => array(
+					'blog_id'   => $blog_id,
+					'permalink' => get_permalink( $post->ID ),
+				),
+			);
+
+			/**
+			 * Filter the data added to the Gallery container.
+			 *
+			 * @module carousel
+			 *
+			 * @since 1.6.0
+			 *
+			 * @param array $extra_data Array of data about the site and the post.
+			 */
+			$extra_data = apply_filters( 'jp_carousel_add_data_to_container', $extra_data );
+			foreach ( (array) $extra_data as $data_key => $data_values ) {
+				$html = str_replace( '<div ', '<div ' . esc_attr( $data_key ) . "='" . json_encode( $data_values ) . "' ", $html );
+				$html = str_replace( '<ul class="wp-block-gallery', '<ul ' . esc_attr( $data_key ) . "='" . json_encode( $data_values ) . "' class=\"wp-block-gallery", $html );
+			}
+		}
+
+		return $html;
+	}
+
+	function get_attachment_comments() {
+		if ( ! headers_sent() ) {
+			header( 'Content-type: text/javascript' );
+		}
+
+		/**
+		 * Allows for the checking of privileges of the blog user before comments
+		 * are packaged as JSON and sent back from the get_attachment_comments
+		 * AJAX endpoint
+		 *
+		 * @module carousel
+		 *
+		 * @since 1.6.0
+		 */
+		do_action( 'jp_carousel_check_blog_user_privileges' );
+
+		$attachment_id = ( isset( $_REQUEST['id'] ) ) ? (int) $_REQUEST['id'] : 0;
+		$offset        = ( isset( $_REQUEST['offset'] ) ) ? (int) $_REQUEST['offset'] : 0;
+
+		if ( ! $attachment_id ) {
+			echo json_encode( __( 'Missing attachment ID.', 'jetpack' ) );
+			die();
+		}
+
+		if ( $offset < 1 ) {
+			$offset = 0;
+		}
+
+		$comments = get_comments(
+			array(
+				'status'  => 'approve',
+				'order'   => ( 'asc' == get_option( 'comment_order' ) ) ? 'ASC' : 'DESC',
+				'number'  => 10,
+				'offset'  => $offset,
+				'post_id' => $attachment_id,
+			)
+		);
+
+		$out = array();
+
+		// Can't just send the results, they contain the commenter's email address.
+		foreach ( $comments as $comment ) {
+			$avatar = get_avatar( $comment->comment_author_email, 64 );
+			if ( ! $avatar ) {
+				$avatar = '';
+			}
+			$out[] = array(
+				'id'              => $comment->comment_ID,
+				'parent_id'       => $comment->comment_parent,
+				'author_markup'   => get_comment_author_link( $comment->comment_ID ),
+				'gravatar_markup' => $avatar,
+				'date_gmt'        => $comment->comment_date_gmt,
+				'content'         => wpautop( $comment->comment_content ),
+			);
+		}
+
+		die( json_encode( $out ) );
+	}
+
+	function post_attachment_comment() {
+		if ( ! headers_sent() ) {
+			header( 'Content-type: text/javascript' );
+		}
+
+		if ( empty( $_POST['nonce'] ) || ! wp_verify_nonce( $_POST['nonce'], 'carousel_nonce' ) ) {
+			die( json_encode( array( 'error' => __( 'Nonce verification failed.', 'jetpack' ) ) ) );
+		}
+
+		$_blog_id = (int) $_POST['blog_id'];
+		$_post_id = (int) $_POST['id'];
+		$comment  = $_POST['comment'];
+
+		if ( empty( $_blog_id ) ) {
+			die( json_encode( array( 'error' => __( 'Missing target blog ID.', 'jetpack' ) ) ) );
+		}
+
+		if ( empty( $_post_id ) ) {
+			die( json_encode( array( 'error' => __( 'Missing target post ID.', 'jetpack' ) ) ) );
+		}
+
+		if ( empty( $comment ) ) {
+			die( json_encode( array( 'error' => __( 'No comment text was submitted.', 'jetpack' ) ) ) );
+		}
+
+		// Used in context like NewDash
+		$switched = false;
+		if ( is_multisite() && $_blog_id != get_current_blog_id() ) {
+			switch_to_blog( $_blog_id );
+			$switched = true;
+		}
+
+		/** This action is documented in modules/carousel/jetpack-carousel.php */
+		do_action( 'jp_carousel_check_blog_user_privileges' );
+
+		if ( ! comments_open( $_post_id ) ) {
+			die( json_encode( array( 'error' => __( 'Comments on this post are closed.', 'jetpack' ) ) ) );
+		}
+
+		if ( is_user_logged_in() ) {
+			$user         = wp_get_current_user();
+			$user_id      = $user->ID;
+			$display_name = $user->display_name;
+			$email        = $user->user_email;
+			$url          = $user->user_url;
+
+			if ( empty( $user_id ) ) {
+				die( json_encode( array( 'error' => __( 'Sorry, but we could not authenticate your request.', 'jetpack' ) ) ) );
+			}
+		} else {
+			$user_id      = 0;
+			$display_name = $_POST['author'];
+			$email        = $_POST['email'];
+			$url          = $_POST['url'];
+
+			if ( get_option( 'require_name_email' ) ) {
+				if ( empty( $display_name ) ) {
+					die( json_encode( array( 'error' => __( 'Please provide your name.', 'jetpack' ) ) ) );
+				}
+
+				if ( empty( $email ) ) {
+					die( json_encode( array( 'error' => __( 'Please provide an email address.', 'jetpack' ) ) ) );
+				}
+
+				if ( ! is_email( $email ) ) {
+					die( json_encode( array( 'error' => __( 'Please provide a valid email address.', 'jetpack' ) ) ) );
+				}
+			}
+		}
+
+		$comment_data = array(
+			'comment_content'      => $comment,
+			'comment_post_ID'      => $_post_id,
+			'comment_author'       => $display_name,
+			'comment_author_email' => $email,
+			'comment_author_url'   => $url,
+			'comment_approved'     => 0,
+			'comment_type'         => '',
+		);
+
+		if ( ! empty( $user_id ) ) {
+			$comment_data['user_id'] = $user_id;
+		}
+
+		// Note: wp_new_comment() sanitizes and validates the values (too).
+		$comment_id = wp_new_comment( $comment_data );
+
+		/**
+		 * Fires before adding a new comment to the database via the get_attachment_comments ajax endpoint.
+		 *
+		 * @module carousel
+		 *
+		 * @since 1.6.0
+		 */
+		do_action( 'jp_carousel_post_attachment_comment' );
+		$comment_status = wp_get_comment_status( $comment_id );
+
+		if ( true == $switched ) {
+			restore_current_blog();
+		}
+
+		die(
+			json_encode(
+				array(
+					'comment_id'     => $comment_id,
+					'comment_status' => $comment_status,
+				)
+			)
+		);
+	}
+
+	function register_settings() {
+		add_settings_section( 'carousel_section', __( 'Image Gallery Carousel', 'jetpack' ), array( $this, 'carousel_section_callback' ), 'media' );
+
+		if ( ! $this->in_jetpack ) {
+			add_settings_field( 'carousel_enable_it', __( 'Enable carousel', 'jetpack' ), array( $this, 'carousel_enable_it_callback' ), 'media', 'carousel_section' );
+			register_setting( 'media', 'carousel_enable_it', array( $this, 'carousel_enable_it_sanitize' ) );
+		}
+
+		add_settings_field( 'carousel_background_color', __( 'Background color', 'jetpack' ), array( $this, 'carousel_background_color_callback' ), 'media', 'carousel_section' );
+		register_setting( 'media', 'carousel_background_color', array( $this, 'carousel_background_color_sanitize' ) );
+
+		add_settings_field( 'carousel_display_exif', __( 'Metadata', 'jetpack' ), array( $this, 'carousel_display_exif_callback' ), 'media', 'carousel_section' );
+		register_setting( 'media', 'carousel_display_exif', array( $this, 'carousel_display_exif_sanitize' ) );
+
+		// No geo setting yet, need to "fuzzify" data first, for privacy
+		// add_settings_field('carousel_display_geo', __( 'Geolocation', 'jetpack' ), array( $this, 'carousel_display_geo_callback' ), 'media', 'carousel_section' );
+		// register_setting( 'media', 'carousel_display_geo', array( $this, 'carousel_display_geo_sanitize' ) );
+	}
+
+	// Fulfill the settings section callback requirement by returning nothing
+	function carousel_section_callback() {
+		return;
+	}
+
+	function test_1or0_option( $value, $default_to_1 = true ) {
+		if ( true == $default_to_1 ) {
+			// Binary false (===) of $value means it has not yet been set, in which case we do want to default sites to 1
+			if ( false === $value ) {
+				$value = 1;
+			}
+		}
+		return ( 1 == $value ) ? 1 : 0;
+	}
+
+	function sanitize_1or0_option( $value ) {
+		return ( 1 == $value ) ? 1 : 0;
+	}
+
+	function settings_checkbox( $name, $label_text, $extra_text = '', $default_to_checked = true ) {
+		if ( empty( $name ) ) {
+			return;
+		}
+		$option = $this->test_1or0_option( get_option( $name ), $default_to_checked );
+		echo '<fieldset>';
+		echo '<input type="checkbox" name="' . esc_attr( $name ) . '" id="' . esc_attr( $name ) . '" value="1" ';
+		checked( '1', $option );
+		echo '/> <label for="' . esc_attr( $name ) . '">' . $label_text . '</label>';
+		if ( ! empty( $extra_text ) ) {
+			echo '<p class="description">' . $extra_text . '</p>';
+		}
+		echo '</fieldset>';
+	}
+
+	function settings_select( $name, $values, $extra_text = '' ) {
+		if ( empty( $name ) || ! is_array( $values ) || empty( $values ) ) {
+			return;
+		}
+		$option = get_option( $name );
+		echo '<fieldset>';
+		echo '<select name="' . esc_attr( $name ) . '" id="' . esc_attr( $name ) . '">';
+		foreach ( $values as $key => $value ) {
+			echo '<option value="' . esc_attr( $key ) . '" ';
+			selected( $key, $option );
+			echo '>' . esc_html( $value ) . '</option>';
+		}
+		echo '</select>';
+		if ( ! empty( $extra_text ) ) {
+			echo '<p class="description">' . $extra_text . '</p>';
+		}
+		echo '</fieldset>';
+	}
+
+	function carousel_display_exif_callback() {
+		$this->settings_checkbox( 'carousel_display_exif', __( 'Show photo metadata (<a href="http://en.wikipedia.org/wiki/Exchangeable_image_file_format" rel="noopener noreferrer" target="_blank">Exif</a>) in carousel, when available.', 'jetpack' ) );
+	}
+
+	function carousel_display_exif_sanitize( $value ) {
+		return $this->sanitize_1or0_option( $value );
+	}
+
+	function carousel_display_geo_callback() {
+		$this->settings_checkbox( 'carousel_display_geo', __( 'Show map of photo location in carousel, when available.', 'jetpack' ) );
+	}
+
+	function carousel_display_geo_sanitize( $value ) {
+		return $this->sanitize_1or0_option( $value );
+	}
+
+	function carousel_background_color_callback() {
+		$this->settings_select(
+			'carousel_background_color', array(
+				'black' => __( 'Black', 'jetpack' ),
+				'white' => __( 'White', 'jetpack' ),
+			)
+		);
+	}
+
+	function carousel_background_color_sanitize( $value ) {
+		return ( 'white' == $value ) ? 'white' : 'black';
+	}
+
+	function carousel_enable_it_callback() {
+		$this->settings_checkbox( 'carousel_enable_it', __( 'Display images in full-size carousel slideshow.', 'jetpack' ) );
+	}
+
+	function carousel_enable_it_sanitize( $value ) {
+		return $this->sanitize_1or0_option( $value );
+	}
+}
+
+new Jetpack_Carousel;