--- /dev/null
+<?php
+/**
+ * Database backend class for storing objects in locally created files.
+ *
+ * This class serializes objects and saves them to local files.
+ *
+ * @author Roland Haeder <webmaster@ship-simu.org>
+ * @version 0.0.0
+ * @copyright Copyright(c) 2007, 2008 Roland Haeder, this is free software
+ * @license GNU GPL 3.0 or any newer version
+ * @link http://www.ship-simu.org
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+class LocalFileDatabase extends BaseDatabaseFrontend implements DatabaseFrontendInterface {
+ /**
+ * Save path for "file database"
+ */
+ private $savePath = "";
+
+ /**
+ * The file's extension
+ */
+ private $fileExtension = "serialized";
+
+ /**
+ * The last read file's name
+ */
+ private $lastFile = "";
+
+ /**
+ * The last read file's content including header information
+ */
+ private $lastContents = array();
+
+ /**
+ * Wether the "connection is already up
+ */
+ private $alreadyConnected = false;
+
+ /**
+ * The private constructor. Do never instance from outside!
+ * You need to set a local file path. The class will then validate it.
+ *
+ * @return void
+ */
+ protected function __construct() {
+ // Call parent constructor
+ parent::__construct(__CLASS__);
+
+ // Set description
+ $this->setObjectDescription("Class for local file databases");
+
+ // Create unique ID
+ $this->createUniqueID();
+
+ // Clean up a little
+ $this->removeSystemArray();
+ }
+
+ /**
+ * Create an object of LocalFileDatabase and set the save path for local files.
+ * This method also validates the given file path.
+ *
+ * @param $savePath The local file path string
+ * @param $ioInstance The input/output handler. This
+ * should be FileIoHandler
+ * @return $dbInstance An instance of LocalFileDatabase
+ */
+ public final static function createLocalFileDatabase ($savePath, FileIoHandler $ioInstance) {
+ // Get an instance
+ $dbInstance = new LocalFileDatabase();
+
+ // Set save path and IO instance
+ $dbInstance->setSavePath($savePath);
+ $dbInstance->setFileIoInstance($ioInstance);
+
+ // "Connect" to the database
+ $dbInstance->connectToDatabase();
+
+ // Return database instance
+ return $dbInstance;
+ }
+
+ /**
+ * Setter for save path
+ *
+ * @param $savePath The local save path where we shall put our serialized classes
+ * @return void
+ */
+ public final function setSavePath ($savePath) {
+ // Secure string
+ $savePath = (string) $savePath;
+
+ // Set save path
+ $this->savePath = $savePath;
+ }
+
+ /**
+ * Getter for save path
+ *
+ * @return $savePath The local save path where we shall put our serialized classes
+ */
+ public final function getSavePath () {
+ return $this->savePath;
+ }
+
+ /**
+ * Saves a given object to the local file system by serializing and
+ * transparently compressing it
+ *
+ * @param $object The object we shall save to the local file system
+ * @return void
+ * @throws NullPointerException If the object instance is null
+ * @throws NoObjectException If the parameter $object is not
+ * an object
+ */
+ public final function saveObject ($object) {
+ // Some tests on the parameter...
+ if (is_null($object)) {
+ // Is null, throw exception
+ throw new NullPointerException($object, self::EXCEPTION_IS_NULL_POINTER);
+ } elseif (!is_object($object)) {
+ // Is not an object, throw exception
+ throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
+ } elseif (!method_exists($object, '__toString')) {
+ // A highly required method was not found... :-(
+ throw new MissingMethodException(array($object, '__toString'), self::EXCEPTION_MISSING_METHOD);
+ }
+
+ // Get a string containing the serialized object. We cannot exchange
+ // $this and $object here because $object does not need to worry
+ // about it's limitations... ;-)
+ $serialized = $this->serializeObject($object);
+
+ // Get a path name plus file name and append the extension
+ $fqfn = $this->getSavePath() . $object->getPathFileNameFromObject() . "." . $this->getFileExtension();
+
+ // Save the file to disc we don't care here if the path is there,
+ // this must be done in later methods.
+ $this->getFileIoInstance()->saveFile($fqfn, array($this->getCompressorChannel()->getCompressorExtension(), $serialized));
+ }
+
+ /**
+ * Get a serialized string from the given object
+ *
+ * @param $object The object we want to serialize and transparently
+ * compress
+ * @return $serialized A string containing the serialzed/compressed object
+ * @see ObjectLimits An object holding limition information
+ * @see SerializationContainer A special container class for e.g.
+ * attributes from limited objects
+ */
+ private function serializeObject ($object) {
+ // If there is no limiter instance we serialize the whole object
+ // otherwise only in the limiter object (ObjectLimits) specified
+ // attributes summarized in a special container class
+ if ($this->getLimitInstance() === null) {
+ // Serialize the whole object. This tribble call is the reason
+ // why we need a fall-back implementation in CompressorChannel
+ // of the methods compressStream() and decompressStream().
+ $serialized = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($object));
+ } else {
+ // Serialize only given attributes in a special container
+ $container = SerializationContainer::createSerializationContainer($this->getLimitInstance(), $object);
+
+ // Serialize the container
+ $serialized = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($container));
+ }
+
+ // Return the serialized object string
+ return $serialized;
+ }
+
+ /**
+ * Analyses if a unique ID has already been used or not by search in the
+ * local database folder.
+ *
+ * @param $uniqueID A unique ID number which shall be checked
+ * before it will be used
+ * @param $inConstructor If we got called in a de/con-structor or
+ * from somewhere else
+ * @return $isUnused true = The unique ID was not found in the database,
+ * false = It is already in use by an other object
+ * @throws NoArrayCreatedException If explode() fails to create an array
+ * @throws InvalidArrayCountException If the array contains less or
+ * more than two elements
+ */
+ public function isUniqueIdUsed ($uniqueID, $inConstructor = false) {
+ // Currently not used... ;-)
+ $isUsed = false;
+
+ // Split the unique ID up in path and file name
+ $pathFile = explode("@", $uniqueID);
+
+ // Are there two elements? Index 0 is the path, 1 the file name + global extension
+ if (!is_array($pathFile)) {
+ // No array found
+ if ($inConstructor) {
+ return false;
+ } else {
+ throw new NoArrayCreatedException(array($this, "pathFile"), self::EXCEPTION_ARRAY_EXPECTED);
+ }
+ } elseif (count($pathFile) != 2) {
+ // Invalid ID returned!
+ if ($inConstructor) {
+ return false;
+ } else {
+ throw new InvalidArrayCountException(array($this, "pathFile", count($pathFile), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
+ }
+ }
+
+ // Create full path name
+ $pathName = $this->getSavePath() . $pathFile[0];
+
+ // Check if the file is there with a file handler
+ if ($inConstructor) {
+ // No exceptions in constructors and destructors!
+ $dirInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName, true);
+
+ // Has an object being created?
+ if (!is_object($dirInstance)) return false;
+ } else {
+ // Outside a constructor
+ try {
+ $dirInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName);
+ } catch (PathIsNoDirectoryException $e) {
+ // Okay, path not found
+ return false;
+ }
+ }
+
+ // Initialize the search loop
+ $isValid = false;
+ while ($dataFile = $dirInstance->readDirectoryExcept(array(".", ".."))) {
+ // Generate FQFN for testing
+ $fqfn = sprintf("%s/%s", $pathName, $dataFile);
+ $this->setLastFile($fqfn);
+
+ // Get instance for file handler
+ $inputHandler = $this->getFileIoInstance();
+
+ // Try to read from it. This makes it sure that the file is
+ // readable and a valid database file
+ $this->setLastFileContents($inputHandler->loadFileContents($fqfn));
+
+ // Extract filename (= unique ID) from it
+ $ID = substr(basename($fqfn), 0, -(strlen($this->getFileExtension()) + 1));
+
+ // Is this the required unique ID?
+ if ($ID == $pathFile[1]) {
+ // Okay, already in use!
+ $isUsed = true;
+ }
+ }
+
+ // Close the directory handler
+ $dirInstance->closeDirectory();
+
+ // Now the same for the file...
+ return $isUsed;
+ }
+
+ /**
+ * Setter for the last read file
+ *
+ * @param $fqfn The FQFN of the last read file
+ * @return void
+ */
+ private final function setLastFile ($fqfn) {
+ // Cast string
+ $fqfn = (string) $fqfn;
+ $this->lastFile = $fqfn;
+ }
+
+ /**
+ * Getter for last read file
+ *
+ * @return $lastFile The last read file's name with full path
+ */
+ public final function getLastFile () {
+ return $this->lastFile;
+ }
+
+ /**
+ * Setter for contents of the last read file
+ *
+ * @param $contents An array with header and data elements
+ * @return void
+ */
+ private final function setLastFileContents ($contents) {
+ // Cast array
+ $contents = (array) $contents;
+ $this->lastContents = $contents;
+ }
+
+ /**
+ * Getter for last read file's content as an array
+ *
+ * @return $lastContent The array with elements 'header' and 'data'.
+ */
+ public final function getLastContents () {
+ return $this->lastContents;
+ }
+
+ /**
+ * Getter for file extension
+ *
+ * @return $fileExtension The array with elements 'header' and 'data'.
+ */
+ public final function getFileExtension () {
+ return $this->fileExtension;
+ }
+
+ /**
+ * Get cached (last fetched) data from the local file database
+ *
+ * @param $uniqueID The ID number for looking up the data
+ * @return $object The restored object from the maybe compressed
+ * serialized data
+ * @throws MismatchingCompressorsException If the compressor from
+ * the loaded file
+ * mismatches with the
+ * current used one.
+ * @throws NullPointerException If the restored object
+ * is null
+ * @throws NoObjectException If the restored "object"
+ * is not an object instance
+ * @throws MissingMethodException If the required method
+ * toString() is missing
+ */
+ public final function getObjectFromCachedData ($uniqueID) {
+ // Get instance for file handler
+ $inputHandler = $this->getFileIoInstance();
+
+ // Get last file's name and contents
+ $fqfn = $this->repairFQFN($this->getLastFile(), $uniqueID);
+ $contents = $this->repairContents($this->getLastContents(), $fqfn);
+
+ // Let's decompress it. First we need the instance
+ $compressInstance = $this->getCompressorChannel();
+
+ // Is the compressor's extension the same as the one from the data?
+ if ($compressInstance->getCompressorExtension() != $contents['header'][0]) {
+ /**
+ * @todo For now we abort here but later we need to make this a little more dynamic.
+ */
+ throw new MismatchingCompressorsException(array($this, $contents['header'][0], $fqfn, $compressInstance->getCompressorExtension()), self::EXCEPTION_MISMATCHING_COMPRESSORS);
+ }
+
+ // Decompress the data now
+ $serialized = $compressInstance->getCompressor()->decompressStream($contents['data']);
+
+ // And unserialize it...
+ $object = unserialize($serialized);
+
+ // This must become a valid object, so let's check it...
+ if (is_null($object)) {
+ // Is null, throw exception
+ throw new NullPointerException($object, self::EXCEPTION_IS_NULL_POINTER);
+ } elseif (!is_object($object)) {
+ // Is not an object, throw exception
+ throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
+ } elseif (!$object instanceof FrameworkInterface) {
+ // A highly required method was not found... :-(
+ throw new MissingMethodException(array($object, '__toString'), self::EXCEPTION_MISSING_METHOD);
+ }
+
+ // And return the object
+ return $object;
+ }
+
+ /**
+ * Private method for re-gathering (repairing) the FQFN
+ *
+ * @param $fqfn The current FQFN we shall validate
+ * @param $uniqueID The unique ID number
+ * @return $fqfn The repaired FQFN when it is empty
+ * @throws NoArrayCreatedException If explode() has not
+ * created an array
+ * @throws InvalidArrayCountException If the array count is not
+ * as the expected
+ */
+ private function repairFQFN ($fqfn, $uniqueID) {
+ // Cast both strings
+ $fqfn = (string) $fqfn;
+ $uniqueID = (string) $uniqueID;
+
+ // Is there pre-cached data available?
+ if (empty($fqfn)) {
+ // Split the unique ID up in path and file name
+ $pathFile = explode("@", $uniqueID);
+
+ // Are there two elements? Index 0 is the path, 1 the file name + global extension
+ if (!is_array($pathFile)) {
+ // No array found
+ throw new NoArrayCreatedException(array($this, "pathFile"), self::EXCEPTION_ARRAY_EXPECTED);
+ } elseif (count($pathFile) != 2) {
+ // Invalid ID returned!
+ throw new InvalidArrayCountException(array($this, "pathFile", count($pathFile), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
+ }
+
+ // Create full path name
+ $pathName = $this->getSavePath() . $pathFile[0];
+
+ // Nothing cached, so let's create a FQFN first
+ $fqfn = sprintf("%s/%s.%s", $pathName, $pathFile[1], $this->getFileExtension());
+ $this->setLastFile($fqfn);
+ }
+
+ // Return repaired FQFN
+ return $fqfn;
+ }
+
+ /**
+ * Private method for re-gathering the contents of a given file
+ *
+ * @param $contents The (maybe) already cached contents as an array
+ * @param $fqfn The current FQFN we shall validate
+ * @return $contents The repaired contents from the given file
+ */
+ private function repairContents ($contents, $fqfn) {
+ // Is there some content and header (2 indexes) in?
+ if ((!is_array($contents)) || (count($contents) != 2) || (!isset($contents['header'])) || (!isset($contents['data']))) {
+ // No content found so load the file again
+ $contents = $inputHandler->loadFileContents($fqfn);
+
+ // And remember all data for later usage
+ $this->setLastContents($contents);
+ }
+
+ // Return the repaired contents
+ return $contents;
+ }
+
+ /**
+ * Makes sure that the database connection is alive
+ *
+ * @return void
+ */
+ public function connectToDatabase () {
+ // @TODO Do some checks on the database directory and files here
+ }
+
+ /**
+ * Loads data saved with saveObject from the database and re-creates a
+ * full object from it.
+ * If limitObject() was called before a new object ObjectContainer with
+ * all requested attributes will be returned instead.
+ *
+ * @return Object The fully re-created object or instance to
+ * ObjectContainer
+ * @throws SavePathIsEmptyException If the given save path is an
+ * empty string
+ * @throws SavePathIsNoDirectoryException If the save path is no
+ * path (e.g. a file)
+ * @throws SavePathReadProtectedException If the save path is read-
+ * protected
+ * @throws SavePathWriteProtectedException If the save path is write-
+ * protected
+ */
+ public function loadObject () {
+ // Already connected? Then abort here
+ if ($this->alreadyConnected === true) return true;
+
+ // Get the save path
+ $savePath = $this->getSavePath();
+
+ if (empty($savePath)) {
+ // Empty string
+ throw new SavePathIsEmptyException($dbInstance, self::EXCEPTION_UNEXPECTED_EMPTY_STRING);
+ } elseif (!is_dir($savePath)) {
+ // Is not a dir
+ throw new SavePathIsNoDirectoryException($savePath, self::EXCEPTION_INVALID_PATH_NAME);
+ } elseif (!is_readable($savePath)) {
+ // Path not readable
+ throw new SavePathReadProtectedException($savePath, self::EXCEPTION_READ_PROTECED_PATH);
+ } elseif (!is_writeable($savePath)) {
+ // Path not writeable
+ throw new SavePathWriteProtectedException($savePath, self::EXCEPTION_WRITE_PROTECED_PATH);
+ }
+
+ // "Connection" established... ;-)
+ $this->alreadyConnected = true;
+ }
+
+ /**
+ * Starts a SELECT query on the database by given return type, table name
+ * and search criteria
+ *
+ * @param $resultType Result type ("array", "object" and "indexed" are valid)
+ * @param $tableName Name of the database table
+ * @param $criteria Local search criteria class
+ * @return $resultData Result data of the query
+ * @throws UnsupportedCriteriaException If the criteria is unsupported
+ */
+ public function querySelect ($resultType, $tableName, Criteria $criteriaInstance) {
+ // Is this criteria supported?
+ if (!$criteriaInstance instanceof LocalCriteria) {
+ // Not supported by this database layer
+ throw new UnsupportedCriteriaException(array($this, $criteriaInstance), self::EXCEPTION_REQUIRED_INTERFACE_MISSING);
+ }
+
+ // A "select" query on local files is not that easy, so begin slowly with it...
+ $this->partialStub(sprintf("type=%s,table=%s,criteria=%s", $resultType, $tableName, $criteriaInstance));
+ }
+}
+
+// [EOF]
+?>
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