/**
 * Plugin Name: Restrict Media Library Access
 * Description: Restricts access for Authors, Contributors, and any role that cannot edit other users' posts so they can only see their own Media Library uploads.
 * Plugin URI: https://wordpress.org/plugins/restrict-media-library-access
 * Version: 1.4.1
 * Author: mrfoxtalbot
 * Author URI: http://mrfoxtalbot.com
 * Text Domain: restrict-media-library-access
 * License: GPLv2
 */

// If this file is called directly, abort.
if ( ! defined( 'WPINC' ) ) {
    die;
}
// Filter Ajax view
add_filter( 'ajax_query_attachments_args', 'mrfx_show_current_user_attachments' );

function mrfx_show_current_user_attachments( $query ) {
    $user_id = get_current_user_id();
    if ( $user_id && !current_user_can('edit_others_posts')) {
        $query['author'] = $user_id;
    }
    return $query;
}
// Filter list view
add_filter( 'request', 'mrfx_show_current_user_attachments_list' );
function mrfx_show_current_user_attachments_list( $query ) {
    $screen = null;
    if ( function_exists( 'get_current_screen' ) ) { 
     $screen = get_current_screen(); 
    } 
    if ( !is_null($screen) && in_array($screen->id, array('upload') ) ) {
        $user_id = get_current_user_id();
        if ( $user_id && !current_user_can('edit_others_posts')) {
            $query['author'] = $user_id;
        }
    }
    return $query;
}