<?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.
 */

/**
 * LoggerAppenderFile appends log events to a file.
 *
 * This appender uses a layout.
 *
 * ## Configurable parameters: ##
 *
 * - **file** - Path to the target file. Relative paths are resolved based on
 *     the working directory.
 * - **append** - If set to true, the appender will append to the file,
 *     otherwise the file contents will be overwritten.
 *
 * @version $Revision: 1382274 $
 * @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/file.html Appender documentation
 */
class LoggerAppenderFile extends LoggerAppender {

    /**
     * If set to true, the file is locked before appending. This allows
     * concurrent access. However, appending without locking is faster so
     * it should be used where appropriate.
     *
     * TODO: make this a configurable parameter
     *
     * @var boolean
     */
    protected $locking = true;

    /**
     * If set to true, appends to file. Otherwise overwrites it.
     * @var boolean
     */
    protected $append = true;

    /**
     * Path to the target file.
     * @var string
     */
    protected $file;

    /**
     * The file resource.
     * @var resource
     */
    protected $fp;

    /**
     * Helper function which can be easily overriden by daily file appender.
     */
    protected function getTargetFile() {
        return $this->file;
    }

    /**
     * Acquires the target file resource, creates the destination folder if
     * necessary. Writes layout header to file.
     *
     * @return boolean FALSE if opening failed
     */
    protected function openFile() {
        $file = $this->getTargetFile();

        // Create the target folder if needed
        if (!is_file($file)) {
            $dir = dirname($file);

            if (!is_dir($dir)) {
                $success = mkdir($dir, 0777, true);
                if ($success === false) {
                    $this->warn("Failed creating target directory [$dir]. Closing appender.");
                    $this->closed = true;
                    return false;
                }
            }
        }

        $mode = $this->append ? 'a' : 'w';
        $this->fp = fopen($file, $mode);
        if ($this->fp === false) {
            $this->warn("Failed opening target file. Closing appender.");
            $this->fp = null;
            $this->closed = true;
            return false;
        }

        // Required when appending with concurrent access
        if ($this->append) {
            fseek($this->fp, 0, SEEK_END);
        }

        // Write the header
        $this->write($this->layout->getHeader());
    }

    /**
     * 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.
            }
        }

        if ($this->locking) {
            $this->writeWithLocking($string);
        } else {
            $this->writeWithoutLocking($string);
        }
    }

    protected function writeWithLocking($string) {
        if (flock($this->fp, LOCK_EX)) {
            if (fwrite($this->fp, $string) === false) {
                $this->warn("Failed writing to file. Closing appender.");
                $this->closed = true;
            }
            flock($this->fp, LOCK_UN);
        } else {
            $this->warn("Failed locking file for writing. Closing appender.");
            $this->closed = true;
        }
    }

    protected function writeWithoutLocking($string) {
        if (fwrite($this->fp, $string) === false) {
            $this->warn("Failed writing to file. Closing appender.");
            $this->closed = true;
        }
    }

    public function activateOptions() {
        if (empty($this->file)) {
            $this->warn("Required parameter 'file' not set. Closing appender.");
            $this->closed = true;
            return;
        }
    }

    public function close() {
        if (is_resource($this->fp)) {
            $this->write($this->layout->getFooter());
            fclose($this->fp);
        }
        $this->fp = null;
        $this->closed = true;
    }

    public function append(LoggerLoggingEvent $event) {
        $this->write($this->layout->format($event));
    }

    /**
     * Sets the 'file' parameter.
     * @param string $file
     */
    public function setFile($file) {
        $this->setString('file', $file);
    }

    /**
     * Returns the 'file' parameter.
     * @return string
     */
    public function getFile() {
        return $this->file;
    }

    /**
     * Returns the 'append' parameter.
     * @return boolean
     */
    public function getAppend() {
        return $this->append;
    }

    /**
     * Sets the 'append' parameter.
     * @param boolean $append
     */
    public function setAppend($append) {
        $this->setBoolean('append', $append);
    }

    /**
     * Sets the 'file' parmeter. Left for legacy reasons.
     * @param string $fileName
     * @deprecated Use setFile() instead.
     */
    public function setFileName($fileName) {
        $this->setFile($fileName);
    }

    /**
     * Returns the 'file' parmeter. Left for legacy reasons.
     * @return string
     * @deprecated Use getFile() instead.
     */
    public function getFileName() {
        return $this->getFile();
    }
}