<?php

/**

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements. See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License. You may obtain a copy of the License at

 *

 *       http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 *

 * @package log4php

 */

/**

 * LoggerAppenderRollingFile writes logging events to a specified file. The

 * file is rolled over after a specified size has been reached.

 *

 * This appender uses a layout.

 *

 * ## Configurable parameters: ##

 *

 * - **file** - Path to the target file.

 * - **append** - If set to true, the appender will append to the file,

 *     otherwise the file contents will be overwritten.

 * - **maxBackupIndex** - Maximum number of backup files to keep. Default is 1.

 * - **maxFileSize** - Maximum allowed file size (in bytes) before rolling

 *     over. Suffixes "KB", "MB" and "GB" are allowed. 10KB = 10240 bytes, etc.

 *     Default is 10M.

 * - **compress** - If set to true, rolled-over files will be compressed.

 *     Requires the zlib extension.

 *

 * @version $Revision: 1394975 $

 * @package log4php

 * @subpackage appenders

 * @license http://www.apache.org/licenses/LICENSE-2.0 Apache License, Version 2.0

 * @link http://logging.apache.org/log4php/docs/appenders/rolling-file.html Appender documentation

 */

class LoggerAppenderRollingFile extends LoggerAppenderFile {

    /** Compressing backup files is done in chunks, this determines how large. */

    const COMPRESS_CHUNK_SIZE = 102400; // 100KB

    /**

     * The maximum size (in bytes) that the output file is allowed to reach

     * before being rolled over to backup files.

     *

     * The default maximum file size is 10MB (10485760 bytes). Maximum value

     * for this option may depend on the file system.

     *

     * @var integer

     */

    protected $maxFileSize = 10485760;

    /**

     * Set the maximum number of backup files to keep around.

     *

     * Determines how many backup files are kept before the oldest is erased.

     * This option takes a positive integer value. If set to zero, then there

     * will be no backup files and the log file will be truncated when it

     * reaches <var>maxFileSize</var>.

     *

     * There is one backup file by default.

     *

     * @var integer

     */

    protected $maxBackupIndex = 1;

    /**

     * The <var>compress</var> parameter determindes the compression with zlib.

     * If set to true, the rollover files are compressed and saved with the .gz extension.

     * @var boolean

     */

    protected $compress = false;

    /**

     * Set to true in the constructor if PHP >= 5.3.0. In that case clearstatcache

     * supports conditional clearing of statistics.

     * @var boolean

     * @see http://php.net/manual/en/function.clearstatcache.php

     */

    private $clearConditional = false;

    /**

     * Get the maximum size that the output file is allowed to reach

     * before being rolled over to backup files.

     * @return integer

     */

    public function getMaximumFileSize() {

        return $this->maxFileSize;

    }

    public function __construct($name = '') {

        parent::__construct($name);

        if (version_compare(PHP_VERSION, '5.3.0') >= 0) {

            $this->clearConditional = true;

        }

    }

    /**

     * Implements the usual roll over behaviour.

     *

     * If MaxBackupIndex is positive, then files File.1, ..., File.MaxBackupIndex -1 are renamed to File.2, ..., File.MaxBackupIndex.

     * Moreover, File is renamed File.1 and closed. A new File is created to receive further log output.

     *

     * If MaxBackupIndex is equal to zero, then the File is truncated with no backup files created.

     *

     * Rollover must be called while the file is locked so that it is safe for concurrent access.

     *

     * @throws LoggerException If any part of the rollover procedure fails.

     */

    private function rollOver() {

        // If maxBackups <= 0, then there is no file renaming to be done.

        if ($this->maxBackupIndex > 0) {

            // Delete the oldest file, to keep Windows happy.

            $file = $this->file . '.' . $this->maxBackupIndex;

            if (file_exists($file) && !unlink($file)) {

                throw new LoggerException("Unable to delete oldest backup file from [$file].");

            }

            // Map {(maxBackupIndex - 1), ..., 2, 1} to {maxBackupIndex, ..., 3, 2}

            $this->renameArchievedLogs($this->file);

            // Backup the active file

            $this->moveToBackup($this->file);

        }

        // Truncate the active file

        ftruncate($this->fp, 0);

        rewind($this->fp);

    }

    private function moveToBackup($source) {

        if ($this->compress) {

            $target = $source . '.1.gz';

            $this->compressFile($source, $target);

        } else {

            $target = $source . '.1';

            copy($source, $target);

        }

    }

    private function compressFile($source, $target) {

        $target = 'compress.zlib://' . $target;

        $fin = fopen($source, 'rb');

        if ($fin === false) {

            throw new LoggerException("Unable to open file for reading: [$source].");

        }

        $fout = fopen($target, 'wb');

        if ($fout === false) {

            throw new LoggerException("Unable to open file for writing: [$target].");

        }

        while (!feof($fin)) {

            $chunk = fread($fin, self::COMPRESS_CHUNK_SIZE);

            if (false === fwrite($fout, $chunk)) {

                throw new LoggerException("Failed writing to compressed file.");

            }

        }

        fclose($fin);

        fclose($fout);

    }

    private function renameArchievedLogs($fileName) {

        for ($i = $this->maxBackupIndex - 1; $i >= 1; $i--) {

            $source = $fileName . "." . $i;

            if ($this->compress) {

                $source .= '.gz';

            }

            if (file_exists($source)) {

                $target = $fileName . '.' . ($i + 1);

                if ($this->compress) {

                    $target .= '.gz';

                }

                rename($source, $target);

            }

        }

    }

    /**

     * Writes a string to the target file. Opens file if not already open.

     * @param string $string Data to write.

     */

    protected function write($string) {

        // Lazy file open

        if (!isset($this->fp)) {

            if ($this->openFile() === false) {

                return; // Do not write if file open failed.

            }

        }

        // Lock the file while writing and possible rolling over

        if (flock($this->fp, LOCK_EX)) {

            // Write to locked file

            if (fwrite($this->fp, $string) === false) {

                $this->warn("Failed writing to file. Closing appender.");

                $this->closed = true;

            }

            // Stats cache must be cleared, otherwise filesize() returns cached results

            // If supported (PHP 5.3+), clear only the state cache for the target file

            if ($this->clearConditional) {

                clearstatcache(true, $this->file);

            } else {

                clearstatcache();

            }

            // Rollover if needed

            if (filesize($this->file) > $this->maxFileSize) {

                try {

                    $this->rollOver();

                } catch (LoggerException $ex) {

                    $this->warn("Rollover failed: " . $ex->getMessage() . " Closing appender.");

                    $this->closed = true;

                }

            }

            flock($this->fp, LOCK_UN);

        } else {

            $this->warn("Failed locking file for writing. Closing appender.");

            $this->closed = true;

        }

    }

    public function activateOptions() {

        parent::activateOptions();

        if ($this->compress && !extension_loaded('zlib')) {

            $this->warn("The 'zlib' extension is required for file compression. Disabling compression.");

            $this->compression = false;

        }

    }

    /**

     * Set the 'maxBackupIndex' parameter.

     * @param integer $maxBackupIndex

     */

    public function setMaxBackupIndex($maxBackupIndex) {

        $this->setPositiveInteger('maxBackupIndex', $maxBackupIndex);

    }

    /**

     * Returns the 'maxBackupIndex' parameter.

     * @return integer

     */

    public function getMaxBackupIndex() {

        return $this->maxBackupIndex;

    }

    /**

     * Set the 'maxFileSize' parameter.

     * @param mixed $maxFileSize

     */

    public function setMaxFileSize($maxFileSize) {

        $this->setFileSize('maxFileSize', $maxFileSize);

    }

    /**

     * Returns the 'maxFileSize' parameter.

     * @return integer

     */

    public function getMaxFileSize() {

        return $this->maxFileSize;

    }

    /**

     * Set the 'maxFileSize' parameter (kept for backward compatibility).

     * @param mixed $maxFileSize

     * @deprecated Use setMaxFileSize() instead.

     */

    public function setMaximumFileSize($maxFileSize) {

        $this->warn("The 'maximumFileSize' parameter is deprecated. Use 'maxFileSize' instead.");

        return $this->setMaxFileSize($maxFileSize);

    }

    /**

     * Sets the 'compress' parameter.

     * @param boolean $compress

     */

    public function setCompress($compress) {

        $this->setBoolean('compress', $compress);

    }

    /**

     * Returns the 'compress' parameter.

     * @param boolean

     */

    public function getCompress() {

        return $this->compress;

    }

}