<?php
/**
 * Object caching using WinCache.
 *
 * 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
 */

/**
 * Wrapper for WinCache object caching functions; identical interface
 * to the APC wrapper
 *
 * @ingroup Cache
 */
class WinCacheBagOStuff extends BagOStuff {
	protected function doGet( $key, $flags = 0 ) {
		$val = wincache_ucache_get( $key );
		if ( is_string( $val ) ) {
			$val = unserialize( $val );
		}

		return $val;
	}

	public function set( $key, $value, $expire = 0, $flags = 0 ) {
		$result = wincache_ucache_set( $key, serialize( $value ), $expire );

		/* wincache_ucache_set returns an empty array on success if $value
		 * was an array, bool otherwise */
		return ( is_array( $result ) && $result === [] ) || $result;
	}

	public function delete( $key ) {
		wincache_ucache_delete( $key );

		return true;
	}

	public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
		if ( wincache_lock( $key ) ) { // optimize with FIFO lock
			$ok = $this->mergeViaLock( $key, $callback, $exptime, $attempts, $flags );
			wincache_unlock( $key );
		} else {
			$ok = false;
		}

		return $ok;
	}

	/**
	 * Construct a cache key.
	 *
	 * @since 1.27
	 * @param string $keyspace
	 * @param array $args
	 * @return string
	 */
	public function makeKeyInternal( $keyspace, $args ) {
		// WinCache keys have a maximum length of 150 characters. From that,
		// subtract the number of characters we need for the keyspace and for
		// the separator character needed for each argument. To handle some
		// custom prefixes used by thing like WANObjectCache, limit to 125.
		// NOTE: Same as in memcached, except the max key length there is 255.
		$charsLeft = 125 - strlen( $keyspace ) - count( $args );

		$args = array_map(
			function ( $arg ) use ( &$charsLeft ) {
				// 33 = 32 characters for the MD5 + 1 for the '#' prefix.
				if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
					$arg = '#' . md5( $arg );
				}

				$charsLeft -= strlen( $arg );
				return $arg;
			},
			$args
		);

		if ( $charsLeft < 0 ) {
			return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
		}

		return $keyspace . ':' . implode( ':', $args );
	}
}