1 files changed, 278 insertions, 0 deletions
diff --git a/www/wiki/includes/cache/FileCacheBase.php b/www/wiki/includes/cache/FileCacheBase.php
new file mode 100644
index 00000000..ce5a019b
--- /dev/null
+++ b/www/wiki/includes/cache/FileCacheBase.php
@@ -0,0 +1,278 @@
+<?php
+/**
+ * Data storage in the file system.
+ *
+ * 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
+ * @ingroup Cache
+ */
+
+/**
+ * Base class for data storage in the file system.
+ *
+ * @ingroup Cache
+ */
+abstract class FileCacheBase {
+	protected $mKey;
+	protected $mType = 'object';
+	protected $mExt = 'cache';
+	protected $mFilePath;
+	protected $mUseGzip;
+	/* lazy loaded */
+	protected $mCached;
+
+	/* @todo configurable? */
+	const MISS_FACTOR = 15; // log 1 every MISS_FACTOR cache misses
+	const MISS_TTL_SEC = 3600; // how many seconds ago is "recent"
+
+	protected function __construct() {
+		global $wgUseGzip;
+
+		$this->mUseGzip = (bool)$wgUseGzip;
+	}
+
+	/**
+	 * Get the base file cache directory
+	 * @return string
+	 */
+	final protected function baseCacheDirectory() {
+		global $wgFileCacheDirectory;
+
+		return $wgFileCacheDirectory;
+	}
+
+	/**
+	 * Get the base cache directory (not specific to this file)
+	 * @return string
+	 */
+	abstract protected function cacheDirectory();
+
+	/**
+	 * Get the path to the cache file
+	 * @return string
+	 */
+	protected function cachePath() {
+		if ( $this->mFilePath !== null ) {
+			return $this->mFilePath;
+		}
+
+		$dir = $this->cacheDirectory();
+		# Build directories (methods include the trailing "/")
+		$subDirs = $this->typeSubdirectory() . $this->hashSubdirectory();
+		# Avoid extension confusion
+		$key = str_replace( '.', '%2E', urlencode( $this->mKey ) );
+		# Build the full file path
+		$this->mFilePath = "{$dir}/{$subDirs}{$key}.{$this->mExt}";
+		if ( $this->useGzip() ) {
+			$this->mFilePath .= '.gz';
+		}
+
+		return $this->mFilePath;
+	}
+
+	/**
+	 * Check if the cache file exists
+	 * @return bool
+	 */
+	public function isCached() {
+		if ( $this->mCached === null ) {
+			$this->mCached = file_exists( $this->cachePath() );
+		}
+
+		return $this->mCached;
+	}
+
+	/**
+	 * Get the last-modified timestamp of the cache file
+	 * @return string|bool TS_MW timestamp
+	 */
+	public function cacheTimestamp() {
+		$timestamp = filemtime( $this->cachePath() );
+
+		return ( $timestamp !== false )
+			? wfTimestamp( TS_MW, $timestamp )
+			: false;
+	}
+
+	/**
+	 * Check if up to date cache file exists
+	 * @param string $timestamp MW_TS timestamp
+	 *
+	 * @return bool
+	 */
+	public function isCacheGood( $timestamp = '' ) {
+		global $wgCacheEpoch;
+
+		if ( !$this->isCached() ) {
+			return false;
+		}
+
+		$cachetime = $this->cacheTimestamp();
+		$good = ( $timestamp <= $cachetime && $wgCacheEpoch <= $cachetime );
+		wfDebug( __METHOD__ .
+			": cachetime $cachetime, touched '{$timestamp}' epoch {$wgCacheEpoch}, good $good\n" );
+
+		return $good;
+	}
+
+	/**
+	 * Check if the cache is gzipped
+	 * @return bool
+	 */
+	protected function useGzip() {
+		return $this->mUseGzip;
+	}
+
+	/**
+	 * Get the uncompressed text from the cache
+	 * @return string
+	 */
+	public function fetchText() {
+		if ( $this->useGzip() ) {
+			$fh = gzopen( $this->cachePath(), 'rb' );
+
+			return stream_get_contents( $fh );
+		} else {
+			return file_get_contents( $this->cachePath() );
+		}
+	}
+
+	/**
+	 * Save and compress text to the cache
+	 * @param string $text
+	 * @return string|false Compressed text
+	 */
+	public function saveText( $text ) {
+		if ( $this->useGzip() ) {
+			$text = gzencode( $text );
+		}
+
+		$this->checkCacheDirs(); // build parent dir
+		if ( !file_put_contents( $this->cachePath(), $text, LOCK_EX ) ) {
+			wfDebug( __METHOD__ . "() failed saving " . $this->cachePath() . "\n" );
+			$this->mCached = null;
+
+			return false;
+		}
+
+		$this->mCached = true;
+
+		return $text;
+	}
+
+	/**
+	 * Clear the cache for this page
+	 * @return void
+	 */
+	public function clearCache() {
+		Wikimedia\suppressWarnings();
+		unlink( $this->cachePath() );
+		Wikimedia\restoreWarnings();
+		$this->mCached = false;
+	}
+
+	/**
+	 * Create parent directors of $this->cachePath()
+	 * @return void
+	 */
+	protected function checkCacheDirs() {
+		wfMkdirParents( dirname( $this->cachePath() ), null, __METHOD__ );
+	}
+
+	/**
+	 * Get the cache type subdirectory (with trailing slash)
+	 * An extending class could use that method to alter the type -> directory
+	 * mapping. @see HTMLFileCache::typeSubdirectory() for an example.
+	 *
+	 * @return string
+	 */
+	protected function typeSubdirectory() {
+		return $this->mType . '/';
+	}
+
+	/**
+	 * Return relative multi-level hash subdirectory (with trailing slash)
+	 * or the empty string if not $wgFileCacheDepth
+	 * @return string
+	 */
+	protected function hashSubdirectory() {
+		global $wgFileCacheDepth;
+
+		$subdir = '';
+		if ( $wgFileCacheDepth > 0 ) {
+			$hash = md5( $this->mKey );
+			for ( $i = 1; $i <= $wgFileCacheDepth; $i++ ) {
+				$subdir .= substr( $hash, 0, $i ) . '/';
+			}
+		}
+
+		return $subdir;
+	}
+
+	/**
+	 * Roughly increments the cache misses in the last hour by unique visitors
+	 * @param WebRequest $request
+	 * @return void
+	 */
+	public function incrMissesRecent( WebRequest $request ) {
+		if ( mt_rand( 0, self::MISS_FACTOR - 1 ) == 0 ) {
+			$cache = ObjectCache::getLocalClusterInstance();
+			# Get a large IP range that should include the user  even if that
+			# person's IP address changes
+			$ip = $request->getIP();
+			if ( !IP::isValid( $ip ) ) {
+				return;
+			}
+			$ip = IP::isIPv6( $ip )
+				? IP::sanitizeRange( "$ip/32" )
+				: IP::sanitizeRange( "$ip/16" );
+
+			# Bail out if a request already came from this range...
+			$key = $cache->makeKey( static::class, 'attempt', $this->mType, $this->mKey, $ip );
+			if ( $cache->get( $key ) ) {
+				return; // possibly the same user
+			}
+			$cache->set( $key, 1, self::MISS_TTL_SEC );
+
+			# Increment the number of cache misses...
+			$key = $this->cacheMissKey( $cache );
+			if ( $cache->get( $key ) === false ) {
+				$cache->set( $key, 1, self::MISS_TTL_SEC );
+			} else {
+				$cache->incr( $key );
+			}
+		}
+	}
+
+	/**
+	 * Roughly gets the cache misses in the last hour by unique visitors
+	 * @return int
+	 */
+	public function getMissesRecent() {
+		$cache = ObjectCache::getLocalClusterInstance();
+
+		return self::MISS_FACTOR * $cache->get( $this->cacheMissKey( $cache ) );
+	}
+
+	/**
+	 * @param BagOStuff $cache Instance that the key will be used with
+	 * @return string
+	 */
+	protected function cacheMissKey( BagOStuff $cache ) {
+		return $cache->makeKey( static::class, 'misses', $this->mType, $this->mKey );
+	}
+}