file.php

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    /**
     * Remove a file
     * 
     * If we can't remove the file (because of locks or any problem), we will touch 
     * the file to invalidate it
     * 
     * @param string $file complete file path
     * @return boolean true if ok
     */  
    private function _remove($file)
    {
        if (!@unlink($file)) {
            # we can't remove the file (because of locks or any problem)
            $this->_log("Zend_Cache_Backend_File::_remove() : we can't remove $file => we are going to try to invalidate it");
            return false;
        } 
        return true;
    }
    
    /**
     * Test if the given cache id is available (and still valid as a cache record)
     * 
     * @param string $id cache id
     * @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
     * @return boolean mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
     */
    private function _test($id, $doNotTestCacheValidity)
    {
        clearstatcache();
        $file = $this->_file($id);
        if (is_null($file)) {
            return false;
        }
        $fileName = @basename($file);
        $expire = (int) $this->_fileNameToExpireField($fileName);
        if ($doNotTestCacheValidity) {
            return $expire;
        }
        if (time() <= $expire) {
            return @filemtime($file);
        }
        return false;
    }
    
    /**
     * Clean some cache records (private method used for recursive stuff)
     *
     * Available modes are :
     * Zend_Cache::CLEANING_MODE_ALL (default)    => remove all cache entries ($tags is not used)
     * Zend_Cache::CLEANING_MODE_OLD              => remove too old cache entries ($tags is not used) 
     * Zend_Cache::CLEANING_MODE_MATCHING_TAG     => remove cache entries matching all given tags 
     *                                               ($tags can be an array of strings or a single string) 
     * Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG => remove cache entries not {matching one of the given tags}
     *                                               ($tags can be an array of strings or a single string)    
     * 
     * @param string $dir directory to clean
     * @param string $mode clean mode
     * @param tags array $tags array of tags
     * @return boolean true if no problem
     */
    private function _clean($dir, $mode = Zend_Cache::CLEANING_MODE_ALL, $tags = array()) 
    {
        if (!is_dir($dir)) {
            return false;
        }
        $result = true;
        $prefix = $this->_options['file_name_prefix'];
        $glob = @glob($dir . $prefix . '--*');
        foreach ($glob as $file)  {
            if (is_file($file)) {
                if ($mode==Zend_Cache::CLEANING_MODE_ALL) {
                    $result = ($result) && ($this->_remove($file));
                }
                if ($mode==Zend_Cache::CLEANING_MODE_OLD) {
                    $fileName = @basename($file);
                    $expire = (int) $this->_fileNameToExpireField($fileName);
                    if (time() > $expire) {
                        $result = ($result) && ($this->_remove($file));
                    }
                }
                if ($mode==Zend_Cache::CLEANING_MODE_MATCHING_TAG) {
                    $matching = true;
                    $id = $this->_fileNameToId(basename($file)); 
                    if (!($this->_isATag($id))) {
                        foreach ($tags as $tag) {
                            if (!($this->_testTag($id, $tag))) {
                                $matching = false;
                                break;
                            }
                        }
                        if ($matching) {
                            $result = ($result) && ($this->remove($id));
                        }
                    }
                }
                if ($mode==Zend_Cache::CLEANING_MODE_NOT_MATCHING_TAG) {
                    $matching = false;
                    $id = $this->_fileNameToId(basename($file));
                    if (!($this->_isATag($id))) {
                        foreach ($tags as $tag) {
                            if ($this->_testTag($id, $tag)) {
                                $matching = true;
                                break;
                            }
                        }
                        if (!$matching) {
                            $result = ($result) && ($this->remove($id));
                        }
                    }                               
                }
            }
            if ((is_dir($file)) and ($this->_options['hashed_directory_level']>0)) {
                // Recursive call
                $result = ($result) && ($this->_clean($file . DIRECTORY_SEPARATOR, $mode, $tags));
                if ($mode=='all') {
                    // if mode=='all', we try to drop the structure too                    
                    @rmdir($file);
                }
            }
        }
        return $result;  
    }
    
    /**
     * Register a cache id with the given tag
     * 
     * @param string $id cache id
     * @param string $tag tag
     * @return boolean true if no problem
     */
    private function _registerTag($id, $tag) 
    {
        return $this->save('1', $this->_tagCacheId($id, $tag));
    }
    
    /**
     * Unregister tags of a cache id
     * 
     * @param string $id cache id
     * @return boolean true if no problem
     */
    private function _unregisterTag($id) 
    {
        $filesToRemove = @glob($this->_file($this->_tagCacheId($id, '*'), '*'));
        $result = true;
        foreach ($filesToRemove as $file) {
            $result = $result && ($this->_remove($file));
        }    
        return $result;    
    }
    
    /**
     * Test if a cache id was saved with the given tag
     * 
     * @param string $id cache id
     * @param string $tag tag name
     * @return true if the cache id was saved with the given tag
     */
    private function _testTag($id, $tag) 
    {
        if ($this->test($this->_tagCacheId($id, $tag))) {
           return true;
        }
        return false;
    }
    
    /**
     * Compute & return the expire time
     * 
     * @return int expire time (unix timestamp)
     */
    private function _expireTime($lifetime) 
    {
        if (is_null($this->_directives['lifetime'])) {
            return 9999999999;
        }
        return time() + $lifetime;
    }
    
    /**
     * Make a control key with the string containing datas
     *
     * @param string $data data
     * @param string $controlType type of control 'md5', 'crc32' or 'strlen'
     * @return string control key
     */
    private function _hash($data, $controlType)
    {
        switch ($controlType) {
        case 'md5':
            return md5($data);
        case 'crc32':
            return sprintf('% 32d', crc32($data));
        case 'strlen':
            return sprintf('% 32d', strlen($data));
        default:
            Zend_Cache::throwException("Incorrect hash function : $controlType");
        }
    }
      
    /**
     * Return a special/reserved cache id for storing the given tag on the given id
     * 
     * @param string $id cache id
     * @param string $tag tag name
     * @return string cache id for the tag
     */
    private function _tagCacheId($id, $tag) {
        return 'internal-' . $id . '-' . $tag;
    }
    
    /**
     * Return true is the given id is a tag
     * 
     * @param string $id
     * @return boolean
     */
    private function _isATag($id)
    {
        if (substr($id, 0, 9) == 'internal-') {
            return true;
        }
        return false;
    }
    
    /**
     * Transform a cache id into a file name and return it
     * 
     * @param string $id cache id
     * @param int expire timestamp
     * @return string file name
     */
    private function _idToFileName($id, $expire)
    {
        $prefix = $this->_options['file_name_prefix'];
        $result = $prefix . '---' . $id . '---' . $expire;
        return $result;
    }
    
    /**
     * Get the father cache id from the tag cache id
     * 
     * @param string $id tag cache id
     * @return string father cache id
     */
    private function _tagCacheIdToFatherCacheId($id)
    {
        return preg_replace('~internal-(\w*)-.*$~', '$1', $id);    
    }
    
    /**
     * Return the expire field from the file name
     * 
     * @param string $fileName
     * @return string expire field
     */
    private function _fileNameToExpireField($fileName)
    {
        $prefix = $this->_options['file_name_prefix'];
        return preg_replace('~^' . $prefix . '---.*---(\d*)$~', '$1', $fileName);
    }
    
    /**
     * Transform a file name into cache id and return it
     * 
     * @param string $fileName file name
     * @return string cache id
     */
    private function _fileNameToId($fileName) 
    {       
        $prefix = $this->_options['file_name_prefix'];
        return preg_replace('~^' . $prefix . '---(.*)---.*$~', '$1', $fileName);
    }
    
    /**
     * Return the complete directory path of a filename (including hashedDirectoryStructure)
     * 
     * @param string $id cache id
     * @return string complete directory path
     */
    private function _path($id)
    {
        $root = $this->_options['cache_dir'];
        $prefix = $this->_options['file_name_prefix'];
        if ($this->_options['hashed_directory_level']>0) {
            if ($this->_isATag($id)) {
                // we store tags in the same directory than the father
                $id2 = $this->_tagCacheIdToFatherCacheId($id);
                $hash = md5($this->_tagCacheIdToFatherCacheId($id));
            } else {
                $hash = md5($id);
            }
            for ($i=0 ; $i<$this->_options['hashed_directory_level'] ; $i++) {
                $root = $root . $prefix . '--' . substr($hash, 0, $i + 1) . DIRECTORY_SEPARATOR;
            }             
        }
        return $root;
    }
    
    /**
     * Make and return a file name (with path)
     *
     * if $expire is null (default), the function try to guess the real file name
     * (if it fails (no cache files or several cache files for this id, the method returns null)
     *
     * @param string $id cache id
     * @param int expire timestamp
     * @return string file name (with path)
     */  
    private function _file($id, $expire = null)
    {
        $path = $this->_path($id);
        if (is_null($expire)) {
            $glob = @glob($path . $this->_idToFileName($id, '*'));
            $nbr = count($glob);
            if ($nbr == 1) {
                return $glob[0];
            }
            return null;       
        }
        $fileName = $this->_idToFileName($id, $expire);
        return $path . $fileName;
    }
    
}