WP_Customize_Manager::handle_dismiss_autosave_or_lock_request()

	public function handle_dismiss_autosave_or_lock_request() {
		// Calls to dismiss_user_auto_draft_changesets() and wp_get_post_autosave() require non-zero get_current_user_id().
		if ( ! is_user_logged_in() ) {
			wp_send_json_error( 'unauthenticated', 401 );
		}

		if ( ! $this->is_preview() ) {
			wp_send_json_error( 'not_preview', 400 );
		}

		if ( ! check_ajax_referer( 'customize_dismiss_autosave_or_lock', 'nonce', false ) ) {
			wp_send_json_error( 'invalid_nonce', 403 );
		}

		$changeset_post_id = $this->changeset_post_id();
		$dismiss_lock = ! empty( $_POST['dismiss_lock'] );
		$dismiss_autosave = ! empty( $_POST['dismiss_autosave'] );

		if ( $dismiss_lock ) {
			if ( empty( $changeset_post_id ) && ! $dismiss_autosave ) {
				wp_send_json_error( 'no_changeset_to_dismiss_lock', 404 );
			}
			if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->edit_post, $changeset_post_id ) && ! $dismiss_autosave ) {
				wp_send_json_error( 'cannot_remove_changeset_lock', 403 );
			}

			delete_post_meta( $changeset_post_id, '_edit_lock' );

			if ( ! $dismiss_autosave ) {
				wp_send_json_success( 'changeset_lock_dismissed' );
			}
		}

		if ( $dismiss_autosave ) {
			if ( empty( $changeset_post_id ) || 'auto-draft' === get_post_status( $changeset_post_id ) ) {
				$dismissed = $this->dismiss_user_auto_draft_changesets();
				if ( $dismissed > 0 ) {
					wp_send_json_success( 'auto_draft_dismissed' );
				} else {
					wp_send_json_error( 'no_auto_draft_to_delete', 404 );
				}
			} else {
				$revision = wp_get_post_autosave( $changeset_post_id, get_current_user_id() );

				if ( $revision ) {
					if ( ! current_user_can( get_post_type_object( 'customize_changeset' )->cap->delete_post, $changeset_post_id ) ) {
						wp_send_json_error( 'cannot_delete_autosave_revision', 403 );
					}

					if ( ! wp_delete_post( $revision->ID, true ) ) {
						wp_send_json_error( 'autosave_revision_deletion_failure', 500 );
					} else {
						wp_send_json_success( 'autosave_revision_deleted' );
					}
				} else {
					wp_send_json_error( 'no_autosave_revision_to_delete', 404 );
				}
			}
		}

		wp_send_json_error( 'unknown_error', 500 );
	}