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<?php
class CacheFichier {
        /**
         * Available options
         *
         * =====> (string) cache_dir :
         * - Directory where to put the cache files
         *
         * =====> (boolean) file_locking :
         * - Enable / disable file_locking
         * - Can avoid cache corruption under bad circumstances but it doesn't work on multithread
         * webservers and on NFS filesystems for example
         *
         * =====> (boolean) read_control :
         * - Enable / disable read control
         * - If enabled, a control key is embeded in cache file and this key is compared with the one
         * calculated after the reading.
         *
         * =====> (string) read_control_type :
         * - Type of read control (only if read control is enabled). Available values are :
         *   'md5' for a md5 hash control (best but slowest)
         *   'crc32' for a crc32 hash control (lightly less safe but faster, better choice)
         *   'adler32' for an adler32 hash control (excellent choice too, faster than crc32)
         *   'strlen' for a length only test (fastest)
         *
         * =====> (int) hashed_directory_level :
         * - Hashed directory level
         * - Set the hashed directory structure level. 0 means "no hashed directory
         * structure", 1 means "one level of directory", 2 means "two levels"...
         * This option can speed up the cache only when you have many thousands of
         * cache file. Only specific benchs can help you to choose the perfect value
         * for you. Maybe, 1 or 2 is a good start.
         *
         * =====> (int) hashed_directory_umask :
         * - Umask for hashed directory structure
         *
         * =====> (string) file_name_prefix :
         * - prefix for cache files
         * - be really carefull with this option because a too generic value in a system cache dir
         *   (like /tmp) can cause disasters when cleaning the cache
         *
         * =====> (int) cache_file_umask :
         * - Umask for cache files
         *
         * =====> (int) metatadatas_array_max_size :
         * - max size for the metadatas array (don't change this value unless you
         *   know what you are doing)
         *
         * @var array available options
         */
        protected $options = array(
                'stockage_chemin' => null,
                'fichier_verrou' => true,
                'controle_lecture' => true,
                'controle_lecture_type' => 'crc32',
                'dossier_niveau' => 0,
                'dossier_umask' => 0700,
                'fichier_prefixe' => 'tbf',
                'fichier_umask' => 0600,
                'metadonnees_max_taille' => 100
        );

        /**
         * Array of metadatas (each item is an associative array)
         *
         * @var array
         */
        protected $metadonnees = array();

        private $Cache = null;
        
        /**
         * Constructor
         *
         * @param  array $options associative array of options
         * @throws Zend_Cache_Exception
         * @return void
         */
        public function __construct(array $options = array(), Cache $cache) {
                $this->Cache = $cache;
                $this->setOptions($options);

                if (isset($this->options['prefixe_fichier'])) {
                        if (!preg_match('~^[a-zA-Z0-9_]+$~D', $this->options['prefixe_fichier'])) {
                                trigger_error("Préfixe de nom de fichier invalide : doit contenir seulement [a-zA-Z0-9_]", E_USER_WARNING);
                        }
                }
                if ($this->options['metadonnees_max_taille'] < 10) {
                        trigger_error("Taille du tableau des méta-données invalide, elle doit être > 10", E_USER_WARNING);
                }
                if (isset($options['dossier_umask']) && is_string($options['dossier_umask'])) {
                        // See #ZF-4422
                        $this->options['dossier_umask'] = octdec($this->options['dossier_umask']);
                }
                if (isset($options['fichier_umask']) && is_string($options['fichier_umask'])) {
                        // See #ZF-4422
                        $this->options['fichier_umask'] = octdec($this->options['fichier_umask']);
                }
        }
        
        private function setOptions($options) {
                while (list($nom, $valeur) = each($options)) {
                        if (!is_string($nom)) {
                                trigger_error("Nom d'option incorecte : $nom", E_USER_WARNING);
                        }
                        $nom = strtolower($nom);
                        if (array_key_exists($nom, $this->options)) {
                                $this->options[$nom] = $valeur;
                        }
                }
        }

        public function setEmplacement($emplacement) {
                if (!is_dir($emplacement)) {
                        trigger_error("L'emplacement doit être un dossier.", E_USER_WARNING);
                }
                if (!is_writable($emplacement)) {
                        trigger_error("Le dossier de stockage du cache n'est pas accessible en écriture", E_USER_WARNING);
                }
                $emplacement = rtrim(realpath($emplacement), '\\/').DS;
                $this->options['stockage_chemin'] = $emplacement;
        }

        /**
         * Test if a cache is available for the given id and (if yes) return it (false else)
         *
         * @param string $id cache id
         * @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested
         * @return string|false cached datas
         */
        public function charger($id, $ne_pas_tester_validiter_du_cache = false) {
                $donnees = false;
                if ($this->tester($id, $ne_pas_tester_validiter_du_cache)) {
                        $metadonnees = $this->getMetadonneesFichier($id);
                        $fichier = $this->getFichierNom($id);
                        $donnees = $this->getContenuFichier($fichier);
                        if ($this->options['controle_lecture']) {
                                $cle_secu_donnees = $this->genererCleSecu($donnees, $this->options['controle_lecture_type']);
                                $cle_secu_controle = $metadonnees['hash'];
                                if ($cle_secu_donnees != $cle_secu_controle) {
                                        // Probléme détecté par le contrôle de lecture !
                                        // TODO : loguer le pb de sécu
                                        $this->supprimer($id);
                                        $donnees = false;
                                }
                        }
                }
                return $donnees;
        }

        /**
         * Teste si un enregistrement en cache est disponible ou pas (pour l'id passé en paramètre).
         *
         * @param string $id identifiant de cache.
         * @return mixed false (le cache n'est pas disponible) ou timestamp (int) "de dernière modification" de l'enregistrement en cache
         */
        public function tester($id) {
                clearstatcache();
                return $this->testerExistenceCache($id, false);
        }

        /**
         * Save some string datas into a cache record
         *
         * Note : $data is always "string" (serialization is done by the
         * core not by the backend)
         *
         * @param  string $data                  Datas to cache
         * @param  string $id                      Cache id
         * @param  array  $tags                  Array of strings, the cache record will be tagged by each string entry
         * @param  int  $specificLifetime If != false, set a specific lifetime for this cache record (null => infinite lifetime)
         * @return boolean true if no problem
         */
        public function sauver($donnees, $id, $tags = array(), $duree_vie_specifique = false) {
                clearstatcache();
                $fichier = $this->getFichierNom($id);
                $chemin = $this->getChemin($id);
                
                $resultat = true;
                if ($this->options['dossier_niveau'] > 0) {
                        if (!is_writable($chemin)) {
                                // maybe, we just have to build the directory structure
                                $this->lancerMkdirEtChmodRecursif($id);
                        }
                        if (!is_writable($chemin)) {
                                $resultat = false;
                        }
                }
                
                if ($resultat === true) {
                        if ($this->options['controle_lecture']) {
                                $cle_secu = $this->genererCleSecu($donnees, $this->options['controle_lecture_type']);
                        } else {
                                $cle_secu = '';
                        }
                        
                        $metadonnees = array(
                                'hash' => $cle_secu,
                                'mtime' => time(),
                                'expiration' => $this->Cache->getTimestampExpiration($duree_vie_specifique),
                                'tags' => $tags
                        );

                        if (! $resultat = $this->setMetadonnees($id, $metadonnees)) {
                                // TODO : ajouter un log
                        } else {
                                $resultat = $this->setContenuFichier($fichier, $donnees);
                        }
                }
                return $resultat;
        }

        /**
         * Remove a cache record
         *
         * @param  string $id cache id
         * @return boolean true if no problem
         */
        public function supprimer($id) {
                $fichier = $this->getFichierNom($id);
                $suppression_fichier = $this->supprimerFichier($fichier);
                $suppression_metadonnees = $this->supprimerMetadonnees($id);
                return $suppression_metadonnees && $suppression_fichier;
        }

        /**
         * Clean some cache records
         *
         * Available modes are :
         * 'all' (default)  => remove all cache entries ($tags is not used)
         * 'old'                        => remove too old cache entries ($tags is not used)
         * 'matchingTag'        => remove cache entries matching all given tags
         *                                       ($tags can be an array of strings or a single string)
         * 'notMatchingTag' => remove cache entries not matching one of the given tags
         *                                       ($tags can be an array of strings or a single string)
         * 'matchingAnyTag' => remove cache entries matching any given tags
         *                                       ($tags can be an array of strings or a single string)
         *
         * @param string $mode clean mode
         * @param tags array $tags array of tags
         * @return boolean true if no problem
         */
        public function nettoyer($mode = Cache::NETTOYAGE_MODE_TOUS, $tags = array()) {
                // We use this protected method to hide the recursive stuff
                clearstatcache();
                return $this->nettoyerFichiers($this->options['stockage_chemin'], $mode, $tags);
        }

        /**
         * Return an array of stored cache ids
         *
         * @return array array of stored cache ids (string)
         */
        public function getIds() {
                return $this->analyserCache($this->options['stockage_chemin'], 'ids', array());
        }

        /**
         * Return an array of stored tags
         *
         * @return array array of stored tags (string)
         */
        public function getTags() {
                return $this->analyserCache($this->options['stockage_chemin'], 'tags', array());
        }

        /**
         * Return an array of stored cache ids which match given tags
         *
         * In case of multiple tags, a logical AND is made between tags
         *
         * @param array $tags array of tags
         * @return array array of matching cache ids (string)
         */
        public function getIdsAvecLesTags($tags = array()) {
                return $this->analyserCache($this->options['stockage_chemin'], 'matching', $tags);
        }

        /**
         * Return an array of stored cache ids which don't match given tags
         *
         * In case of multiple tags, a logical OR is made between tags
         *
         * @param array $tags array of tags
         * @return array array of not matching cache ids (string)
         */
        public function getIdsSansLesTags($tags = array()) {
                return $this->analyserCache($this->options['stockage_chemin'], 'notMatching', $tags);
        }

        /**
         * Return an array of stored cache ids which match any given tags
         *
         * In case of multiple tags, a logical AND is made between tags
         *
         * @param array $tags array of tags
         * @return array array of any matching cache ids (string)
         */
        public function getIdsAvecUnTag($tags = array()) {
                return $this->analyserCache($this->options['stockage_chemin'], 'matchingAny', $tags);
        }

        /**
         * Return the filling percentage of the backend storage
         *
         * @throws Zend_Cache_Exception
         * @return int integer between 0 and 100
         */
        public function getPourcentageRemplissage() {
                $libre = disk_free_space($this->options['stockage_chemin']);
                $total = disk_total_space($this->options['stockage_chemin']);
                
                $pourcentage = 0;
                if ($total == 0) {
                        trigger_error("Impossible d'utiliser la fonction disk_total_space", E_USER_WARNING);
                } else {
                        $pourcentage = ($libre >= $total) ? 100 : ((int) (100. * ($total - $libre) / $total));
                }
                return $pourcentage;
        }

        /**
         * Return an array of metadatas for the given cache id
         *
         * The array must include these keys :
         * - expire : the expire timestamp
         * - tags : a string array of tags
         * - mtime : timestamp of last modification time
         *
         * @param string $id cache id
         * @return array array of metadatas (false if the cache id is not found)
         */
        public function getMetadonnees($id) {
                if ($metadonnees = $this->getMetadonneesFichier($id)) {
                        if (time() > $metadonnees['expiration']) {
                                $metadonnees = false;
                        } else {
                                $metadonnees = array(
                                        'expiration' => $metadonnees['expiration'],
                                        'tags' => $metadonnees['tags'],
                                        'mtime' => $metadonnees['mtime']
                                );
                        }
                }
                
                return $metadonnees;
        }

        /**
         * Give (if possible) an extra lifetime to the given cache id
         *
         * @param string $id cache id
         * @param int $extraLifetime
         * @return boolean true if ok
         */
        public function ajouterSupplementDureeDeVie($id, $supplement_duree_de_vie) {
                $augmentation = true;
                if ($metadonnees = $this->getMetadonneesFichier($id)) {
                        if (time() > $metadonnees['expiration']) {
                                $augmentation = false;
                        } else {
                                $metadonnees_nouvelle = array(
                                        'hash' => $metadonnees['hash'],
                                        'mtime' => time(),
                                        'expiration' => $metadonnees['expiration'] + $supplement_duree_de_vie,
                                        'tags' => $metadonnees['tags']
                                );
                                $augmentation = $this->setMetadonnees($id, $metadonnees_nouvelle);
                        }
                }
                return $augmentation;
        }

        /**
         * Get a metadatas record
         *
         * @param  string $id  Cache id
         * @return array|false Associative array of metadatas
         */
        protected function getMetadonneesFichier($id) {
                $metadonnees = false;
                if (isset($this->metadonnees[$id])) {
                        $metadonnees = $this->metadonnees[$id];
                } else {
                        if ($metadonnees = $this->chargerMetadonnees($id)) {
                                $this->setMetadonnees($id, $metadonnees, false);
                        }
                }
                return $metadonnees;
        }

        /**
         * Set a metadatas record
         *
         * @param  string $id           Cache id
         * @param  array  $metadatas Associative array of metadatas
         * @param  boolean $save         optional pass false to disable saving to file
         * @return boolean True if no problem
         */
        protected function setMetadonnees($id, $metadonnees, $sauvegarde = true) {
                if (count($this->metadonnees) >= $this->options['metadonnees_max_taille']) {
                        $n = (int) ($this->options['metadonnees_max_taille'] / 10);
                        $this->metadonnees = array_slice($this->metadonnees, $n);
                }
                
                $resultat = true;
                if ($sauvegarde) {
                        $resultat = $this->sauverMetadonnees($id, $metadonnees);
                }
                if ($resultat == true) {
                        $this->metadonnees[$id] = $metadonnees;
                }
                return $resultat;
        }

        /**
         * Drop a metadata record
         *
         * @param  string $id Cache id
         * @return boolean True if no problem
         */
        protected function supprimerMetadonnees($id) {
                if (isset($this->metadonnees[$id])) {
                        unset($this->metadonnees[$id]);
                }
                $fichier_meta = $this->getNomFichierMeta($id);
                return $this->supprimerFichier($fichier_meta);
        }

        /**
         * Clear the metadatas array
         *
         * @return void
         */
        protected function nettoyerMetadonnees() {
                $this->metadonnees = array();
        }

        /**
         * Load metadatas from disk
         *
         * @param  string $id Cache id
         * @return array|false Metadatas associative array
         */
        protected function chargerMetadonnees($id) {
                $fichier = $this->getNomFichierMeta($id);
                if ($resultat = $this->getContenuFichier($fichier)) {
                        $resultat = @unserialize($resultat);
                }
                return $resultat;
        }

        /**
         * Save metadatas to disk
         *
         * @param  string $id           Cache id
         * @param  array  $metadatas Associative array
         * @return boolean True if no problem
         */
        protected function sauverMetadonnees($id, $metadonnees) {
                $fichier = $this->getNomFichierMeta($id);
                $resultat = $this->setContenuFichier($fichier, serialize($metadonnees));
                return $resultat;
        }

        /**
         * Make and return a file name (with path) for metadatas
         *
         * @param  string $id Cache id
         * @return string Metadatas file name (with path)
         */
        protected function getNomFichierMeta($id) {
                $chemin = $this->getChemin($id);
                $fichier_nom = $this->transformaterIdEnNomFichier('interne-meta---'.$id);
                return $chemin.$fichier_nom;
        }

        /**
         * Check if the given filename is a metadatas one
         *
         * @param  string $fileName File name
         * @return boolean True if it's a metadatas one
         */
        protected function etreFichierMeta($fichier_nom) {
                $id = $this->transformerNomFichierEnId($fichier_nom);
                return (substr($id, 0, 21) == 'interne-meta---') ? true : false;
        }

        /**
         * 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 $file Complete file path
         * @return boolean True if ok
         */
        protected function supprimerFichier($fichier) {
                $resultat = false;
                if (is_file($fichier)) {
                        if ($resultat = @unlink($fichier)) {
                                // TODO : ajouter un log
                        }
                }
                return $resultat;
        }

        /**
         * Clean some cache records (protected 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)
         * Zend_Cache::CLEANING_MODE_MATCHING_ANY_TAG => remove cache entries matching any 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  array  $tags Array of tags
         * @throws Zend_Cache_Exception
         * @return boolean True if no problem
         */
        protected function nettoyerFichiers($dossier, $mode = Cache::NETTOYAGE_MODE_TOUS, $tags = array()) {
                if (!is_dir($dossier)) {
                        return false;
                }
                $resultat = true;
                $prefixe = $this->options['fichier_prefixe'];
                $glob = @glob($dossier.$prefixe.'--*');
                if ($glob === false) {
                        // On some systems it is impossible to distinguish between empty match and an error.
                        return true;
                }
                foreach ($glob as $fichier)  {
                        if (is_file($fichier)) {
                                $fichier_nom = basename($fichier);
                                if ($this->etreFichierMeta($fichier_nom)) {
                                        // Pour le mode Cache::NETTOYAGE_MODE_TOUS, nous essayons de tous supprimer même les vieux fichiers méta
                                        if ($mode != Cache::NETTOYAGE_MODE_TOUS) {
                                                continue;
                                        }
                                }
                                $id = $this->transformerNomFichierEnId($fichier_nom);
                                $metadonnees = $this->getMetadonneesFichier($id);
                                if ($metadonnees === FALSE) {
                                        $metadonnees = array('expiration' => 1, 'tags' => array());
                                }
                                switch ($mode) {
                                        case Cache::NETTOYAGE_MODE_TOUS :
                                                if ($resultat_suppression = $this->supprimer($id)) {
                                                        // Dans ce cas seulement, nous acception qu'il y ait un problème avec la suppresssion du fichier meta
                                                        $resultat_suppression = $this->supprimerFichier($fichier);
                                                }
                                                $resultat = $resultat && $resultat_suppression;
                                                break;
                                        case Cache::NETTOYAGE_MODE_EXPIRATION :
                                                if (time() > $metadonnees['expiration']) {
                                                        $resultat = $this->supprimer($id) && $resultat;
                                                }
                                                break;
                                        case Cache::NETTOYAGE_MODE_AVEC_LES_TAGS :
                                                $correspondance = true;
                                                foreach ($tags as $tag) {
                                                        if (!in_array($tag, $metadonnees['tags'])) {
                                                                $correspondance = false;
                                                                break;
                                                        }
                                                }
                                                if ($correspondance) {
                                                        $resultat = $this->supprimer($id) && $resultat;
                                                }
                                                break;
                                        case Cache::NETTOYAGE_MODE_SANS_LES_TAGS :
                                                $correspondance = false;
                                                foreach ($tags as $tag) {
                                                        if (in_array($tag, $metadonnees['tags'])) {
                                                                $correspondance = true;
                                                                break;
                                                        }
                                                }
                                                if (!$correspondance) {
                                                        $resultat = $this->supprimer($id) && $resultat;
                                                }
                                                break;
                                        case Cache::NETTOYAGE_MODE_AVEC_UN_TAG :
                                                $correspondance = false;
                                                foreach ($tags as $tag) {
                                                        if (in_array($tag, $metadonnees['tags'])) {
                                                                $correspondance = true;
                                                                break;
                                                        }
                                                }
                                                if ($correspondance) {
                                                        $resultat = $this->supprimer($id) && $resultat;
                                                }
                                                break;
                                        default:
                                                trigger_error("Mode de nettoyage invalide pour la méthode nettoyer()", E_USER_WARNING);
                                                break;
                                }
                        }
                        if ((is_dir($fichier)) and ($this->options['dossier_niveau'] > 0)) {
                                // Appel récursif
                                $resultat = $this->nettoyerFichiers($fichier.DS, $mode, $tags) && $resultat;
                                if ($mode == Cache::NETTOYAGE_MODE_TOUS) {
                                        // Si mode == Cache::NETTOYAGE_MODE_TOUS, nous essayons de supprimer la structure aussi
                                        @rmdir($fichier);
                                }
                        }
                }
                return $resultat;
        }

        protected function analyserCache($dossier, $mode, $tags = array()) {
                if (!is_dir($dossier)) {
                        return false;
                }
                $resultat = array();
                $prefixe = $this->options['fichier_prefixe'];
                $glob = @glob($dossier.$prefixe.'--*');
                if ($glob === false) {
                        // On some systems it is impossible to distinguish between empty match and an error.
                        return array();
                }
                foreach ($glob as $fichier)  {
                        if (is_file($fichier)) {
                                $nom_fichier = basename($fichier);
                                $id = $this->transformerNomFichierEnId($nom_fichier);
                                $metadonnees = $this->getMetadonneesFichier($id);
                                if ($metadonnees === FALSE) {
                                        continue;
                                }
                                if (time() > $metadonnees['expiration']) {
                                        continue;
                                }
                                switch ($mode) {
                                        case 'ids':
                                                $resultat[] = $id;
                                                break;
                                        case 'tags':
                                                $resultat = array_unique(array_merge($resultat, $metadonnees['tags']));
                                                break;
                                        case 'matching':
                                                $correspondance = true;
                                                foreach ($tags as $tag) {
                                                        if (!in_array($tag, $metadonnees['tags'])) {
                                                                $correspondance = false;
                                                                break;
                                                        }
                                                }
                                                if ($correspondance) {
                                                        $resultat[] = $id;
                                                }
                                                break;
                                        case 'notMatching':
                                                $correspondance = false;
                                                foreach ($tags as $tag) {
                                                        if (in_array($tag, $metadonnees['tags'])) {
                                                                $correspondance = true;
                                                                break;
                                                        }
                                                }
                                                if (!$correspondance) {
                                                        $resultat[] = $id;
                                                }
                                                break;
                                        case 'matchingAny':
                                                $correspondance = false;
                                                foreach ($tags as $tag) {
                                                        if (in_array($tag, $metadonnees['tags'])) {
                                                                $correspondance = true;
                                                                break;
                                                        }
                                                }
                                                if ($correspondance) {
                                                        $resultat[] = $id;
                                                }
                                                break;
                                        default:
                                                trigger_error("Mode invalide pour la méthode analyserCache()", E_USER_WARNING);
                                                break;
                                }
                        }
                        if ((is_dir($fichier)) and ($this->options['dossier_niveau'] > 0)) {
                                // Appel récursif
                                $resultat_analyse_recursive = $this->analyserCache($fichier.DS, $mode, $tags);
                                if ($resultat_analyse_recursive === false) {
                                        // TODO : ajoute un log
                                } else {
                                        $resultat = array_unique(array_merge($resultat, $resultat_analyse_recursive));
                                }
                        }
                }
                return array_unique($resultat);
        }

        /**
         * Make a control key with the string containing datas
         *
         * @param  string $data         Data
         * @param  string $controlType Type of control 'md5', 'crc32' or 'strlen'
         * @throws Zend_Cache_Exception
         * @return string Control key
         */
        protected function genererCleSecu($donnees, $type_de_controle) {
                switch ($type_de_controle) {
                case 'md5':
                        return md5($donnees);
                case 'crc32':
                        return crc32($donnees);
                case 'strlen':
                        return strlen($donnees);
                case 'adler32':
                        return hash('adler32', $donnees);
                default:
                        trigger_error("Fonction de génération de clé de sécurité introuvable : $type_de_controle", E_USER_WARNING);
                }
        }

        /**
         * Transform a cache id into a file name and return it
         *
         * @param  string $id Cache id
         * @return string File name
         */
        protected function transformaterIdEnNomFichier($id) {
                $prefixe = $this->options['fichier_prefixe'];
                $resultat = $prefixe.'---'.$id;
                return $resultat;
        }

        /**
         * Make and return a file name (with path)
         *
         * @param  string $id Cache id
         * @return string File name (with path)
         */
        protected function getFichierNom($id) {
                $path = $this->getChemin($id);
                $fileName = $this->transformaterIdEnNomFichier($id);
                return $path . $fileName;
        }

        /**
         * Return the complete directory path of a filename (including hashedDirectoryStructure)
         *
         * @param  string $id Cache id
         * @param  boolean $decoupage if true, returns array of directory parts instead of single string
         * @return string Complete directory path
         */
        protected function getChemin($id, $decoupage = false) {
                $morceaux = array();
                $chemin = $this->options['stockage_chemin'];
                $prefixe = $this->options['fichier_prefixe'];
                if ($this->options['dossier_niveau'] > 0) {
                        $hash = hash('adler32', $id);
                        for ($i = 0 ; $i < $this->options['dossier_niveau'] ; $i++) {
                                $chemin .= $prefixe.'--'.substr($hash, 0, $i + 1).DS;
                                $morceaux[] = $chemin;
                        }
                }
                return ($decoupage) ?   $morceaux : $chemin;
        }

        /**
         * Make the directory strucuture for the given id
         *
         * @param string $id cache id
         * @return boolean true
         */
        protected function lancerMkdirEtChmodRecursif($id) {
                $resultat = true;
                if ($this->options['dossier_niveau'] > 0) {
                        $chemins = $this->getChemin($id, true);
                        foreach ($chemins as $chemin) {
                                if (!is_dir($chemin)) {
                                        @mkdir($chemin, $this->options['dossier_umask']);
                                        @chmod($chemin, $this->options['dossier_umask']); // see #ZF-320 (this line is required in some configurations)
                                }
                        }
                }
                return $resultat;
        }

        /**
         * Test if the given cache id is available (and still valid as a cache record)
         *
         * @param  string  $id                                   Cache id
         * @param  boolean $doNotTestCacheValidity If set to true, the cache validity won't be tested
         * @return boolean|mixed false (a cache is not available) or "last modified" timestamp (int) of the available cache record
         */
        protected function testerExistenceCache($id, $ne_pas_tester_validiter_du_cache) {
                $resultat = false;
                if ($metadonnees = $this->getMetadonnees($id)) {
                        if ($ne_pas_tester_validiter_du_cache || (time() <= $metadonnees['expiration'])) {
                                $resultat =  $metadonnees['mtime'];
                        }
                }
                return $resultat;
        }

        /**
         * Return the file content of the given file
         *
         * @param  string $file File complete path
         * @return string File content (or false if problem)
         */
        protected function getContenuFichier($fichier) {
                $resultat = false;
                if (is_file($fichier)) {
                        $f = @fopen($fichier, 'rb');
                        if ($f) {
                                if ($this->options['fichier_verrou']) @flock($f, LOCK_SH);
                                $resultat = stream_get_contents($f);
                                if ($this->options['fichier_verrou']) @flock($f, LOCK_UN);
                                @fclose($f);
                        }
                }
                return $resultat;
        }

        /**
         * Put the given string into the given file
         *
         * @param  string $file   File complete path
         * @param  string $string String to put in file
         * @return boolean true if no problem
         */
        protected function setContenuFichier($fichier, $chaine) {
                $resultat = false;
                $f = @fopen($fichier, 'ab+');
                if ($f) {
                        if ($this->options['fichier_verrou']) @flock($f, LOCK_EX);
                        fseek($f, 0);
                        ftruncate($f, 0);
                        $tmp = @fwrite($f, $chaine);
                        if (!($tmp === FALSE)) {
                                $resultat = true;
                        }
                        @fclose($f);
                }
                @chmod($fichier, $this->options['fichier_umask']);
                return $resultat;
        }

        /**
         * Transform a file name into cache id and return it
         *
         * @param  string $fileName File name
         * @return string Cache id
         */
        protected function transformerNomFichierEnId($nom_de_fichier) {
                $prefixe = $this->options['fichier_prefixe'];
                return preg_replace('~^' . $prefixe . '---(.*)$~', '$1', $nom_de_fichier);
        }
}
?>