$message, $path, $rules );

				$exs->push( $ex );
				return;
			}
		} else {
			// writing to own rules file in cache folder
			if ( !@file_exists( dirname( $path ) ) ) {
				Util_File::mkdir_from( dirname( $path ), W3TC_CACHE_DIR );
			}

			if ( !@file_put_contents( $path, $data ) ) {
				try {
					Util_WpFile::delete_folder(
						dirname( $path ),
						'',
						isset( $_SERVER['REQUEST_URI'] ) ? sanitize_text_field( wp_unslash( $_SERVER['REQUEST_URI'] ) ) : ''
					);
				} catch ( Util_WpFile_FilesystemOperationException $ex ) {
					$exs->push( $ex );
					return;
				}
			}
		}

		Util_Rule::after_rules_modified();
	}



	/**
	 * Called when rules are modified, sets notification
	 */
	static public function after_rules_modified() {
		if ( Util_Environment::is_nginx() ) {
			$state = Dispatcher::config_state_master();
			$state->set( 'common.show_note.nginx_restart_required', true );
			$state->save();
		}
	}



	/**
	 * Remove rules
	 */
	static public function remove_rules( $exs, $path, $start, $end ) {
		if ( !file_exists( $path ) )
			return;

		$data = @file_get_contents( $path );
		if ( $data === false )
			return;
		if ( strstr( $data, $start ) === false )
			return;

		$data = Util_Rule::erase_rules( $data, $start,
			$end );

		try {
			Util_WpFile::write_to_file( $path, $data );
		} catch ( Util_WpFile_FilesystemOperationException $ex ) {
			$exs->push( new Util_WpFile_FilesystemModifyException(
					$ex->getMessage(), $ex->credentials_form(),
					sprintf( __( 'Edit file <strong>%s</strong> and remove all lines between and including <strong>%s</strong>
				and <strong>%s</strong> markers.', 'w3-total-cache' ), $path, $start, $end ), $path ) );
		}
	}

	/**
	 * Returns path of pgcache cache rules file
	 * Moved to separate file to not load rule.php for each disk enhanced request
	 *
	 * @return string
	 */
	static public function get_pgcache_rules_cache_path() {
		switch ( true ) {
		case Util_Environment::is_apache():
		case Util_Environment::is_litespeed():
			if ( Util_Environment::is_wpmu() ) {
				$url = get_home_url();
				$match = null;
				if ( preg_match( '~http(s)?://(.+?)(/)?$~', $url, $match ) ) {
					$home_path = $match[2];

					return W3TC_CACHE_PAGE_ENHANCED_DIR . DIRECTORY_SEPARATOR .
						$home_path . DIRECTORY_SEPARATOR . '.htaccess';
				}
			}

			return W3TC_CACHE_PAGE_ENHANCED_DIR . DIRECTORY_SEPARATOR . '.htaccess';

		case Util_Environment::is_nginx():
			return Util_Rule::get_nginx_rules_path();
		}

		return false;
	}

	/**
	 * Returns true if we can check rules
	 *
	 * @return bool
	 */
	static public function can_check_rules() {
		return Util_Environment::is_apache() ||
			Util_Environment::is_litespeed() ||
			Util_Environment::is_nginx() ||
			Util_Environment::is_iis();
	}

	/**
	 * Support for GoDaddy servers configuration which uses.
	 * SUBDOMAIN_DOCUMENT_ROOT variable.
	 */
	public static function apache_docroot_variable() {
		$document_root           = isset( $_SERVER['DOCUMENT_ROOT'] ) ? esc_url_raw( wp_unslash( $_SERVER['DOCUMENT_ROOT'] ) ) : '';
		$subdomain_document_root = isset( $_SERVER['SUBDOMAIN_DOCUMENT_ROOT'] ) ? esc_url_raw( wp_unslash( $_SERVER['SUBDOMAIN_DOCUMENT_ROOT'] ) ) : '';
		$php_document_root       = isset( $_SERVER['PHP_DOCUMENT_ROOT'] ) ? esc_url_raw( wp_unslash( $_SERVER['PHP_DOCUMENT_ROOT'] ) ) : '';
		if ( ! empty( $subdomain_document_root ) && $subdomain_document_root !== $document_root ) {
			return '%{ENV:SUBDOMAIN_DOCUMENT_ROOT}';
		} elseif ( ! empty( $php_document_root ) && $php_document_root !== $document_root ) {
			return '%{ENV:PHP_DOCUMENT_ROOT}';
		} else {
			return '%{DOCUMENT_ROOT}';
		}
	}



	/**
	 * Takes an array of extensions single per row and/or extensions delimited by |
	 *
	 * @param unknown $extensions
	 * @param unknown $ext
	 * @return array
	 */
	static public function remove_extension_from_list( $extensions, $ext ) {
		for ( $i = 0; $i < sizeof( $extensions ); $i++ ) {
			if ( $extensions[$i] == $ext ) {
				unset( $extensions[$i] );
				return $extensions;
			} elseif ( strpos( $extensions[$i], $ext ) !== false &&
				strpos( $extensions[$i], '|' ) !== false ) {
				$exts = explode( '|', $extensions[$i] );
				$key = array_search( $ext, $exts );
				unset( $exts[$key] );
				$extensions[$i] = implode( '|', $exts );
				return $extensions;
			}
		}
		return $extensions;
	}
}