MediaWiki 1.30.2

[autoinstallsdev/mediawiki.git] / includes / utils / FileContentsHasher.php

diff --git a/includes/utils/FileContentsHasher.php b/includes/utils/FileContentsHasher.php
new file mode 100644 (file)
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+++ b/includes/utils/FileContentsHasher.php
@@ -0,0 +1,114 @@
+<?php
+/**
+ * Generate hash digests of file contents to help with cache invalidation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+class FileContentsHasher {
+
+       /** @var BagOStuff */
+       protected $cache;
+
+       /** @var FileContentsHasher */
+       private static $instance;
+
+       public function __construct() {
+               $this->cache = ObjectCache::getLocalServerInstance( 'hash' );
+       }
+
+       /**
+        * Get the singleton instance of this class.
+        *
+        * @return FileContentsHasher
+        */
+       public static function singleton() {
+               if ( !self::$instance ) {
+                       self::$instance = new self;
+               }
+
+               return self::$instance;
+       }
+
+       /**
+        * Get a hash of a file's contents, either by retrieving a previously-
+        * computed hash from the cache, or by computing a hash from the file.
+        *
+        * @private
+        * @param string $filePath Full path to the file.
+        * @param string $algo Name of selected hashing algorithm.
+        * @return string|bool Hash of file contents, or false if the file could not be read.
+        */
+       public function getFileContentsHashInternal( $filePath, $algo = 'md4' ) {
+               $mtime = filemtime( $filePath );
+               if ( $mtime === false ) {
+                       return false;
+               }
+
+               $cacheKey = $this->cache->makeGlobalKey( __CLASS__, $filePath, $mtime, $algo );
+               $hash = $this->cache->get( $cacheKey );
+
+               if ( $hash ) {
+                       return $hash;
+               }
+
+               $contents = file_get_contents( $filePath );
+               if ( $contents === false ) {
+                       return false;
+               }
+
+               $hash = hash( $algo, $contents );
+               $this->cache->set( $cacheKey, $hash, 60 * 60 * 24 );  // 24h
+
+               return $hash;
+       }
+
+       /**
+        * Get a hash of the combined contents of one or more files, either by
+        * retrieving a previously-computed hash from the cache, or by computing
+        * a hash from the files.
+        *
+        * @param string|string[] $filePaths One or more file paths.
+        * @param string $algo Name of selected hashing algorithm.
+        * @return string|bool Hash of files' contents, or false if no file could not be read.
+        */
+       public static function getFileContentsHash( $filePaths, $algo = 'md4' ) {
+               $instance = self::singleton();
+
+               if ( !is_array( $filePaths ) ) {
+                       $filePaths = (array)$filePaths;
+               }
+
+               MediaWiki\suppressWarnings();
+
+               if ( count( $filePaths ) === 1 ) {
+                       $hash = $instance->getFileContentsHashInternal( $filePaths[0], $algo );
+                       MediaWiki\restoreWarnings();
+                       return $hash;
+               }
+
+               sort( $filePaths );
+               $hashes = array_map( function ( $filePath ) use ( $instance, $algo ) {
+                       return $instance->getFileContentsHashInternal( $filePath, $algo ) ?: '';
+               }, $filePaths );
+
+               MediaWiki\restoreWarnings();
+
+               $hashes = implode( '', $hashes );
+               return $hashes ? hash( $algo, $hashes ) : false;
+       }
+}