Defined (1)

The function is defined in the following location(s).

/wp-admin/includes/revision.php  

function wp_get_revision_ui_diff( $post, $compare_from, $compare_to ) { 
    if ( ! $post = get_post( $post ) ) 
        return false; 
 
    if ( $compare_from ) { 
        if ( ! $compare_from = get_post( $compare_from ) ) 
            return false; 
    } else { 
        // If we're dealing with the first revision... 
        $compare_from = false; 
    } 
 
    if ( ! $compare_to = get_post( $compare_to ) ) 
        return false; 
 
    // If comparing revisions, make sure we're dealing with the right post parent. 
    // The parent post may be a 'revision' when revisions are disabled and we're looking at autosaves. 
    if ( $compare_from && $compare_from->post_parent !== $post->ID && $compare_from->ID !== $post->ID ) 
        return false; 
    if ( $compare_to->post_parent !== $post->ID && $compare_to->ID !== $post->ID ) 
        return false; 
 
    if ( $compare_from && strtotime( $compare_from->post_date_gmt ) > strtotime( $compare_to->post_date_gmt ) ) { 
        $temp = $compare_from; 
        $compare_from = $compare_to; 
        $compare_to = $temp; 
    } 
 
    // Add default title if title field is empty 
    if ( $compare_from && empty( $compare_from->post_title ) ) 
        $compare_from->post_title = __( '(no title)' ); 
    if ( empty( $compare_to->post_title ) ) 
        $compare_to->post_title = __( '(no title)' ); 
 
    $return = array(); 
 
    foreach ( _wp_post_revision_fields( $post ) as $field => $name ) { 
        /** 
         * Contextually filter a post revision field. 
         * 
         * The dynamic portion of the hook name, `$field`, corresponds to each of the post 
         * fields of the revision object being iterated over in a foreach statement. 
         * 
         * @since 3.6.0 
         * 
         * @param string  $compare_from->$field The current revision field to compare to or from. 
         * @param string  $field                The current revision field. 
         * @param WP_Post $compare_from         The revision post object to compare to or from. 
         * @param string  null                  The context of whether the current revision is the old 
         *                                      or the new one. Values are 'to' or 'from'. 
         */ 
        $content_from = $compare_from ? apply_filters( "_wp_post_revision_field_{$field}", $compare_from->$field, $field, $compare_from, 'from' ) : ''; 
 
        /** This filter is documented in wp-admin/includes/revision.php */ 
        $content_to = apply_filters( "_wp_post_revision_field_{$field}", $compare_to->$field, $field, $compare_to, 'to' ); 
 
        $args = array( 
            'show_split_view' => true 
 ); 
 
        /** 
         * Filters revisions text diff options. 
         * 
         * Filters the options passed to wp_text_diff() when viewing a post revision. 
         * 
         * @since 4.1.0 
         * 
         * @param array   $args { 
         *     Associative array of options to pass to wp_text_diff(). 
         * 
         *     @type bool $show_split_view True for split view (two columns), false for 
         *                                 un-split view (single column). Default true. 
         * } 
         * @param string  $field        The current revision field. 
         * @param WP_Post $compare_from The revision post to compare from. 
         * @param WP_Post $compare_to   The revision post to compare to. 
         */ 
        $args = apply_filters( 'revision_text_diff_options', $args, $field, $compare_from, $compare_to ); 
 
        $diff = wp_text_diff( $content_from, $content_to, $args ); 
 
        if ( ! $diff && 'post_title' === $field ) { 
            // It's a better user experience to still show the Title, even if it didn't change. 
            // No, you didn't see this. 
            $diff = '<table class="diff"><colgroup><col class="content diffsplit left"><col class="content diffsplit middle"><col class="content diffsplit right"></colgroup><tbody><tr>'; 
            $diff .= '<td>' . esc_html( $compare_from->post_title ) . '</td><td></td><td>' . esc_html( $compare_to->post_title ) . '</td>'; 
            $diff .= '</tr></tbody>'; 
            $diff .= '</table>'; 
        } 
 
        if ( $diff ) { 
            $return[] = array( 
                'id' => $field,  
                'name' => $name,  
                'diff' => $diff,  
 ); 
        } 
    } 
 
    /** 
     * Filters the fields displayed in the post revision diff UI. 
     * 
     * @since 4.1.0 
     * 
     * @param array   $return       Revision UI fields. Each item is an array of id, name and diff. 
     * @param WP_Post $compare_from The revision post to compare from. 
     * @param WP_Post $compare_to   The revision post to compare to. 
     */ 
    return apply_filters( 'wp_get_revision_ui_diff', $return, $compare_from, $compare_to ); 
 
}