/**
 * Ajax handler for getting revision diffs.
 *
 * @since 3.6.0
 */
function wp_ajax_get_revision_diffs()
{
    require ABSPATH . 'wp-admin/includes/revision.php';
    if (!($post = get_post((int) $_REQUEST['post_id']))) {
        wp_send_json_error();
    }
    if (!current_user_can('read_post', $post->ID)) {
        wp_send_json_error();
    }
    // Really just pre-loading the cache here.
    if (!($revisions = wp_get_post_revisions($post->ID, array('check_enabled' => false)))) {
        wp_send_json_error();
    }
    $return = array();
    @set_time_limit(0);
    foreach ($_REQUEST['compare'] as $compare_key) {
        list($compare_from, $compare_to) = explode(':', $compare_key);
        // from:to
        $return[] = array('id' => $compare_key, 'fields' => wp_get_revision_ui_diff($post, $compare_from, $compare_to));
    }
    wp_send_json_success($return);
}

/**
 * Prepare revisions for JavaScript.
 *
 * @since 3.6.0
 *
 * @param object $post The post object.
 * @param int $selected_revision_id The selected revision id.
 * @param int $from (optional) The revision id to compare from.
 *
 * @return array An associative array of revision data and related settings.
 */
function wp_prepare_revisions_for_js($post, $selected_revision_id, $from = null)
{
    $post = get_post($post);
    $revisions = $authors = array();
    $now_gmt = time();
    $revisions = wp_get_post_revisions($post->ID, array('order' => 'ASC', 'check_enabled' => false));
    // If revisions are disabled, we only want autosaves and the current post.
    if (!wp_revisions_enabled($post)) {
        foreach ($revisions as $revision_id => $revision) {
            if (!wp_is_post_autosave($revision)) {
                unset($revisions[$revision_id]);
            }
        }
        $revisions = array($post->ID => $post) + $revisions;
    }
    $show_avatars = get_option('show_avatars');
    cache_users(wp_list_pluck($revisions, 'post_author'));
    $can_restore = current_user_can('edit_post', $post->ID);
    foreach ($revisions as $revision) {
        $modified = strtotime($revision->post_modified);
        $modified_gmt = strtotime($revision->post_modified_gmt);
        if ($can_restore) {
            $restore_link = str_replace('&', '&', wp_nonce_url(add_query_arg(array('revision' => $revision->ID, 'action' => 'restore'), admin_url('revision.php')), "restore-post_{$revision->ID}"));
        }
        if (!isset($authors[$revision->post_author])) {
            $authors[$revision->post_author] = array('id' => (int) $revision->post_author, 'avatar' => $show_avatars ? get_avatar($revision->post_author, 32) : '', 'name' => get_the_author_meta('display_name', $revision->post_author));
        }
        $autosave = (bool) wp_is_post_autosave($revision);
        $current = !$autosave && $revision->post_modified_gmt === $post->post_modified_gmt;
        if ($current && !empty($current_id)) {
            // If multiple revisions have the same post_modified_gmt, highest ID is current.
            if ($current_id < $revision->ID) {
                $revisions[$current_id]['current'] = false;
                $current_id = $revision->ID;
            } else {
                $current = false;
            }
        } elseif ($current) {
            $current_id = $revision->ID;
        }
        $revisions[$revision->ID] = array('id' => $revision->ID, 'title' => get_the_title($post->ID), 'author' => $authors[$revision->post_author], 'date' => date_i18n(__('M j, Y @ G:i'), $modified), 'dateShort' => date_i18n(_x('j M @ G:i', 'revision date short format'), $modified), 'timeAgo' => sprintf(__('%s ago'), human_time_diff($modified_gmt, $now_gmt)), 'autosave' => $autosave, 'current' => $current, 'restoreUrl' => $can_restore ? $restore_link : false);
    }
    // If a post has been saved since the last revision (no revisioned fields were changed)
    // we may not have a "current" revision. Mark the latest revision as "current".
    if (empty($current_id)) {
        if ($revisions[$revision->ID]['autosave']) {
            $revision = end($revisions);
            while ($revision['autosave']) {
                $revision = prev($revisions);
            }
            $current_id = $revision['id'];
        } else {
            $current_id = $revision->ID;
        }
        $revisions[$current_id]['current'] = true;
    }
    // Now, grab the initial diff
    $compare_two_mode = is_numeric($from);
    if (!$compare_two_mode) {
        $found = array_search($selected_revision_id, array_keys($revisions));
        if ($found) {
            $from = array_keys(array_slice($revisions, $found - 1, 1, true));
            $from = reset($from);
        } else {
            $from = 0;
        }
    }
    $from = absint($from);
    $diffs = array(array('id' => $from . ':' . $selected_revision_id, 'fields' => wp_get_revision_ui_diff($post->ID, $from, $selected_revision_id)));
    return array('postId' => $post->ID, 'nonce' => wp_create_nonce('revisions-ajax-nonce'), 'revisionData' => array_values($revisions), 'to' => $selected_revision_id, 'from' => $from, 'diffData' => $diffs, 'baseUrl' => parse_url(admin_url('revision.php'), PHP_URL_PATH), 'compareTwoMode' => absint($compare_two_mode), 'revisionIds' => array_keys($revisions));
}

//.........这里部分代码省略.........
    // If revisions are disabled, we only want autosaves and the current post.
    if (!wp_revisions_enabled($post)) {
        foreach ($revisions as $revision_id => $revision) {
            if (!wp_is_post_autosave($revision)) {
                unset($revisions[$revision_id]);
            }
        }
        $revisions = array($post->ID => $post) + $revisions;
    }
    $show_avatars = get_option('show_avatars');
    cache_users(wp_list_pluck($revisions, 'post_author'));
    $can_restore = current_user_can('edit_post', $post->ID);
    $current_id = false;
    foreach ($revisions as $revision) {
        $modified = strtotime($revision->post_modified);
        $modified_gmt = strtotime($revision->post_modified_gmt);
        if ($can_restore) {
            $restore_link = str_replace('&', '&', wp_nonce_url(add_query_arg(array('revision' => $revision->ID, 'action' => 'restore'), admin_url('revision.php')), "restore-post_{$revision->ID}"));
        }
        if (!isset($authors[$revision->post_author])) {
            $authors[$revision->post_author] = array('id' => (int) $revision->post_author, 'avatar' => $show_avatars ? get_avatar($revision->post_author, 32) : '', 'name' => get_the_author_meta('display_name', $revision->post_author));
        }
        $autosave = (bool) wp_is_post_autosave($revision);
        $current = !$autosave && $revision->post_modified_gmt === $post->post_modified_gmt;
        if ($current && !empty($current_id)) {
            // If multiple revisions have the same post_modified_gmt, highest ID is current.
            if ($current_id < $revision->ID) {
                $revisions[$current_id]['current'] = false;
                $current_id = $revision->ID;
            } else {
                $current = false;
            }
        } elseif ($current) {
            $current_id = $revision->ID;
        }
        $revisions_data = array('id' => $revision->ID, 'title' => get_the_title($post->ID), 'author' => $authors[$revision->post_author], 'date' => date_i18n(__('M j, Y @ H:i'), $modified), 'dateShort' => date_i18n(_x('j M @ H:i', 'revision date short format'), $modified), 'timeAgo' => sprintf(__('%s ago'), human_time_diff($modified_gmt, $now_gmt)), 'autosave' => $autosave, 'current' => $current, 'restoreUrl' => $can_restore ? $restore_link : false);
        /**
         * Filter the array of revisions used on the revisions screen.
         *
         * @since 4.4.0
         *
         * @param array   $revisions_data {
         *     The bootstrapped data for the revisions screen.
         *
         *     @type int        $id         Revision ID.
         *     @type string     $title      Title for the revision's parent WP_Post object.
         *     @type int        $author     Revision post author ID.
         *     @type string     $date       Date the revision was modified.
         *     @type string     $dateShort  Short-form version of the date the revision was modified.
         *     @type string     $timeAgo    GMT-aware amount of time ago the revision was modified.
         *     @type bool       $autosave   Whether the revision is an autosave.
         *     @type bool       $current    Whether the revision is both not an autosave and the post
         *                                  modified date matches the revision modified date (GMT-aware).
         *     @type bool|false $restoreUrl URL if the revision can be restored, false otherwise.
         * }
         * @param WP_Post $revision       The revision's WP_Post object.
         * @param WP_Post $post           The revision's parent WP_Post object.
         */
        $revisions[$revision->ID] = apply_filters('wp_prepare_revision_for_js', $revisions_data, $revision, $post);
    }
    /**
     * If we only have one revision, the initial revision is missing; This happens
     * when we have an autsosave and the user has clicked 'View the Autosave'
     */
    if (1 === sizeof($revisions)) {
        $revisions[$post->ID] = array('id' => $post->ID, 'title' => get_the_title($post->ID), 'author' => $authors[$post->post_author], 'date' => date_i18n(__('M j, Y @ H:i'), strtotime($post->post_modified)), 'dateShort' => date_i18n(_x('j M @ H:i', 'revision date short format'), strtotime($post->post_modified)), 'timeAgo' => sprintf(__('%s ago'), human_time_diff(strtotime($post->post_modified_gmt), $now_gmt)), 'autosave' => false, 'current' => true, 'restoreUrl' => false);
        $current_id = $post->ID;
    }
    /*
     * If a post has been saved since the last revision (no revisioned fields
     * were changed), we may not have a "current" revision. Mark the latest
     * revision as "current".
     */
    if (empty($current_id)) {
        if ($revisions[$revision->ID]['autosave']) {
            $revision = end($revisions);
            while ($revision['autosave']) {
                $revision = prev($revisions);
            }
            $current_id = $revision['id'];
        } else {
            $current_id = $revision->ID;
        }
        $revisions[$current_id]['current'] = true;
    }
    // Now, grab the initial diff.
    $compare_two_mode = is_numeric($from);
    if (!$compare_two_mode) {
        $found = array_search($selected_revision_id, array_keys($revisions));
        if ($found) {
            $from = array_keys(array_slice($revisions, $found - 1, 1, true));
            $from = reset($from);
        } else {
            $from = 0;
        }
    }
    $from = absint($from);
    $diffs = array(array('id' => $from . ':' . $selected_revision_id, 'fields' => wp_get_revision_ui_diff($post->ID, $from, $selected_revision_id)));
    return array('postId' => $post->ID, 'nonce' => wp_create_nonce('revisions-ajax-nonce'), 'revisionData' => array_values($revisions), 'to' => $selected_revision_id, 'from' => $from, 'diffData' => $diffs, 'baseUrl' => parse_url(admin_url('revision.php'), PHP_URL_PATH), 'compareTwoMode' => absint($compare_two_mode), 'revisionIds' => array_keys($revisions));
}