3 * Generate hash digests of file contents to help with cache invalidation.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
22 class FileContentsHasher
{
27 /** @var FileContentsHasher */
28 private static $instance;
30 public function __construct() {
31 $this->cache
= ObjectCache
::getLocalServerInstance( 'hash' );
35 * Get the singleton instance of this class.
37 * @return FileContentsHasher
39 public static function singleton() {
40 if ( !self
::$instance ) {
41 self
::$instance = new self
;
44 return self
::$instance;
48 * Get a hash of a file's contents, either by retrieving a previously-
49 * computed hash from the cache, or by computing a hash from the file.
52 * @param string $filePath Full path to the file.
53 * @param string $algo Name of selected hashing algorithm.
54 * @return string|bool Hash of file contents, or false if the file could not be read.
56 public function getFileContentsHashInternal( $filePath, $algo = 'md4' ) {
57 $mtime = filemtime( $filePath );
58 if ( $mtime === false ) {
62 $cacheKey = $this->cache
->makeGlobalKey( __CLASS__
, $filePath, $mtime, $algo );
63 $hash = $this->cache
->get( $cacheKey );
69 $contents = file_get_contents( $filePath );
70 if ( $contents === false ) {
74 $hash = hash( $algo, $contents );
75 $this->cache
->set( $cacheKey, $hash, 60 * 60 * 24 ); // 24h
81 * Get a hash of the combined contents of one or more files, either by
82 * retrieving a previously-computed hash from the cache, or by computing
83 * a hash from the files.
85 * @param string|string[] $filePaths One or more file paths.
86 * @param string $algo Name of selected hashing algorithm.
87 * @return string|bool Hash of files' contents, or false if no file could not be read.
89 public static function getFileContentsHash( $filePaths, $algo = 'md4' ) {
90 $instance = self
::singleton();
92 if ( !is_array( $filePaths ) ) {
93 $filePaths = (array)$filePaths;
96 Wikimedia\
suppressWarnings();
98 if ( count( $filePaths ) === 1 ) {
99 $hash = $instance->getFileContentsHashInternal( $filePaths[0], $algo );
100 Wikimedia\restoreWarnings
();
105 $hashes = array_map( function ( $filePath ) use ( $instance, $algo ) {
106 return $instance->getFileContentsHashInternal( $filePath, $algo ) ?
: '';
109 Wikimedia\restoreWarnings
();
111 $hashes = implode( '', $hashes );
112 return $hashes ?
hash( $algo, $hashes ) : false;