inc/classes/main/database/classes/class_LocalFileDatabase.php

   1 <?php
   2 /**
   3  * Database backend class for storing objects in locally created files.
   4  *
   5  * This class serializes objects and saves them to local files.
   6  *
   7  * @author              Roland Haeder <webmaster@mxchange.org>
   8  * @version             0.3.0
   9  * @copyright   Copyright(c) 2007, 2008 Roland Haeder, this is free software
  10  * @license             GNU GPL 3.0 or any newer version
  11  * @link                http://www.mxchange.org
  12  *
  13  * This program is free software: you can redistribute it and/or modify
  14  * it under the terms of the GNU General Public License as published by
  15  * the Free Software Foundation, either version 3 of the License, or
  16  * (at your option) any later version.
  17  *
  18  * This program is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21  * GNU General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU General Public License
  24  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  25  */
  26 class LocalFileDatabase extends BaseDatabaseFrontend implements DatabaseFrontendInterface {
  27         /**
  28          * Save path for "file database"
  29          */
  30         private $savePath = "";
  31
  32         /**
  33          * The file's extension
  34          */
  35         private $fileExtension = "serialized";
  36
  37         /**
  38          * The IO handler for file handling which should be FileIOHandler.
  39          */
  40         private $ioInstance = null;
  41
  42         /**
  43          * The last read file's name
  44          */
  45         private $lastFile = "";
  46
  47         /**
  48          * The last read file's content including header information
  49          */
  50         private $lastContents = array();
  51
  52         /**
  53          * The private constructor. Do never instance from outside!
  54          * You need to set a local file path. The class will then validate it.
  55          *
  56          * @return      void
  57          */
  58         private function __construct() {
  59                 // Call parent constructor
  60                 parent::constructor(__CLASS__);
  61
  62                 // Set description
  63                 $this->setPartDescr("Dateidatenbankschicht");
  64
  65                 // Create unique ID
  66                 $this->createUniqueID();
  67
  68                 // Clean up a little
  69                 $this->removeSystemArray();
  70         }
  71
  72         /**
  73          * Create an object of LocalFileDatabase and set the save path for local files.
  74          * This method also validates the given file path.
  75          *
  76          * @param               $savePath                                       The local file path string
  77          * @param               $ioInstance                             The input/output handler. This
  78          *                                                                      should be FileIOHandler
  79          * @return      $dbInstance                             An instance of LocalFileDatabase
  80          * @throws      SavePathIsEmptyException                If the given save path is an
  81          *                                                                      empty string
  82          * @throws      SavePathIsNoDirectoryException  If the save path is no
  83          *                                                                              path (e.g. a file)
  84          * @throws      SavePathReadProtectedException  If the save path is read-
  85          *                                                                              protected
  86          * @throws      SavePathWriteProtectedException If the save path is write-
  87          *                                                                              protected
  88          */
  89         public final static function createLocalFileDatabase ($savePath, FileIOHandler $ioInstance) {
  90                 // Get an instance
  91                 $dbInstance = new LocalFileDatabase();
  92
  93                 if (empty($savePath)) {
  94                         // Empty string
  95                         throw new SavePathIsEmptyException($dbInstance, self::EXCEPTION_UNEXPECTED_EMPTY_STRING);
  96                 } elseif (!is_dir($savePath)) {
  97                         // Is not a dir
  98                         throw new SavePathIsNoDirectoryException($savePath, self::EXCEPTION_INVALID_PATH_NAME);
  99                 } elseif (!is_readable($savePath)) {
 100                         // Path not readable
 101                         throw new SavePathReadProtectedException($savePath, self::EXCEPTION_READ_PROTECED_PATH);
 102                 } elseif (!is_writeable($savePath)) {
 103                         // Path not writeable
 104                         throw new SavePathWriteProtectedException($savePath, self::EXCEPTION_WRITE_PROTECED_PATH);
 105                 }
 106
 107                 // Debug output
 108                 if (defined('DEBUG_DATABASE')) $dbInstance->getDebugInstance()->output(sprintf("[%s:] Es werden lokale Dateien zum Speichern von Objekten verwendet.<br />\n",
 109                         $dbInstance->__toString()
 110                 ));
 111
 112                 // Set save path and IO instance
 113                 $dbInstance->setSavePath($savePath);
 114                 $dbInstance->setIOInstance($ioInstance);
 115
 116                 // Return database instance
 117                 return $dbInstance;
 118         }
 119
 120         /**
 121          * Setter for save path
 122          *
 123          * @param               $savePath               The local save path where we shall put our serialized classes
 124          * @return      void
 125          */
 126         public final function setSavePath ($savePath) {
 127                 // Secure string
 128                 $savePath = (string) $savePath;
 129
 130                 // Debug message
 131                 if ((defined('DEBUG_DATABASE')) || (defined('DEBUG_ALL'))) $this->getDebugInstance()->output(sprintf("[%s:] Lokaler Speicherpfad <strong>%s</strong> wird verwendet.<br />\n",
 132                         $this->__toString(),
 133                         $savePath
 134                 ));
 135
 136                 // Set save path
 137                 $this->savePath = $savePath;
 138         }
 139
 140         /**
 141          * Getter for save path
 142          *
 143          * @return      $savePath               The local save path where we shall put our serialized classes
 144          */
 145         public final function getSavePath () {
 146                 return $this->savePath;
 147         }
 148
 149         /**
 150          * Getter for file extension
 151          *
 152          * @return      $fileExtension          The file extension for all file names
 153          */
 154         public final function getFileExtension () {
 155                 return $this->fileExtension;
 156         }
 157
 158         /**
 159          * Saves a given object to the local file system by serializing and
 160          * transparently compressing it
 161          *
 162          * @param               $object                         The object we shall save to the local file system
 163          * @return      void
 164          * @throws      NullPointerException    If the object instance is null
 165          * @throws      NoObjectException               If the parameter $object is not
 166          *                                                              an object
 167          */
 168         public final function saveObject ($object) {
 169                 // Some tests on the parameter...
 170                 if (is_null($object)) {
 171                         // Is null, throw exception
 172                         throw new NullPointerException($object, self::EXCEPTION_IS_NULL_POINTER);
 173                 } elseif (!is_object($object)) {
 174                         // Is not an object, throw exception
 175                         throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
 176                 } elseif (!method_exists($object, '__toString')) {
 177                         // A highly required method was not found... :-(
 178                         throw new MissingMethodException(array($object, '__toString'), self::EXCEPTION_MISSING_METHOD);
 179                 }
 180
 181                 // Debug message
 182                 if ((defined('DEBUG_DATABASE')) || (defined('DEBUG_ALL'))) $this->getDebugInstance()->output(sprintf("[%s:] Das Objekt <strong>%s</strong> soll in eine lokale Datei gespeichert werden.<br />\n",
 183                         $this->__toString(),
 184                         $object->__toString()
 185                 ));
 186
 187                 // Get a string containing the serialized object. We cannot exchange
 188                 // $this and $object here because $object does not need to worry
 189                 // about it's limitations... ;-)
 190                 $serialized = $this->serializeObject($object);
 191
 192                 // Debug message
 193                 if ((defined('DEBUG_DATABASE')) || (defined('DEBUG_ALL'))) $this->getDebugInstance()->output(sprintf("[%s:] Das Objekt <strong>%s</strong> ist nach der Serialisierung <strong>%s</strong> Byte gross.<br />\n",
 194                         $this->__toString(),
 195                         $object->__toString(),
 196                         strlen($serialized)
 197                 ));
 198
 199                 // Get a path name plus file name and append the extension
 200                 $fqfn = $this->getSavePath() . $object->getPathFileNameFromObject() . "." . $this->getFileExtension();
 201
 202                 // Save the file to disc we don't care here if the path is there,
 203                 // this must be done in later methods.
 204                 $this->getIOInstance()->saveFile($fqfn, array($this->getCompressorChannel()->getCompressorExtension(), $serialized));
 205         }
 206
 207         /**
 208          * Get a serialized string from the given object
 209          *
 210          * @param               $object         The object we want to serialize and transparently
 211          *                                              compress
 212          * @return      $serialized     A string containing the serialzed/compressed object
 213          * @see         ObjectLimits    An object holding limition information
 214          * @see         SerializationContainer  A special container class for e.g.
 215          *                                                              attributes from limited objects
 216          */
 217         private function serializeObject ($object) {
 218                 // If there is no limiter instance we serialize the whole object
 219                 // otherwise only in the limiter object (ObjectLimits) specified
 220                 // attributes summarized in a special container class
 221                 if ($this->getLimitInstance() === null) {
 222                         // Serialize the whole object. This tribble call is the reason
 223                         // why we need a fall-back implementation in CompressorChannel
 224                         // of the methods compressStream() and decompressStream().
 225                         $serialized = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($object));
 226                 } else {
 227                         // Serialize only given attributes in a special container
 228                         $container = SerializationContainer::createSerializationContainer($this->getLimitInstance(), $object);
 229
 230                         // Serialize the container
 231                         $serialized = $this->getCompressorChannel()->getCompressor()->compressStream(serialize($container));
 232                 }
 233
 234                 // Return the serialized object string
 235                 return $serialized;
 236         }
 237
 238         /**
 239          * Analyses if a unique ID has already been used or not by search in the
 240          * local database folder.
 241          *
 242          * @param               $uniqueID               A unique ID number which shall be checked
 243          *                                              before it will be used
 244          * @param               $inConstructor  If we got called in a de/con-structor or
 245          *                                              from somewhere else
 246          * @return      $isUnused               true    = The unique ID was not found in the database,
 247          *                                              false = It is already in use by an other object
 248          * @throws      NoArrayCreatedException If explode() fails to create an array
 249          * @throws      InvalidArrayCountException      If the array contains less or
 250          *                                                                      more than two elements
 251          */
 252         public function isUniqueIdUsed ($uniqueID, $inConstructor = false) {
 253                 // Currently not used... ;-)
 254                 $isUsed = false;
 255
 256                 // Split the unique ID up in path and file name
 257                 $pathFile = explode("@", $uniqueID);
 258
 259                 // Are there two elements? Index 0 is the path, 1 the file name + global extension
 260                 if (!is_array($pathFile)) {
 261                         // No array found
 262                         if ($inConstructor) {
 263                                 return false;
 264                         } else {
 265                                 throw new NoArrayCreatedException(array($this, "pathFile"), self::EXCEPTION_ARRAY_EXPECTED);
 266                         }
 267                 } elseif (count($pathFile) != 2) {
 268                         // Invalid ID returned!
 269                         if ($inConstructor) {
 270                                 return false;
 271                         } else {
 272                                 throw new InvalidArrayCountException(array($this, "pathFile", count($pathFile), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
 273                         }
 274                 }
 275
 276                 // Create full path name
 277                 $pathName = $this->getSavePath() . $pathFile[0];
 278
 279                 // Check if the file is there with a file handler
 280                 if ($inConstructor) {
 281                         // No exceptions in constructors and destructors!
 282                         $dirInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName, true);
 283
 284                         // Has an object being created?
 285                         if (!is_object($dirInstance)) return false;
 286                 } else {
 287                         // Outside a constructor
 288                         try {
 289                                 $dirInstance = FrameworkDirectoryPointer::createFrameworkDirectoryPointer($pathName);
 290                         } catch (PathIsNoDirectoryException $e) {
 291                                 // Okay, path not found
 292                                 return false;
 293                         }
 294                 }
 295
 296                 // Initialize the search loop
 297                 $isValid = false;
 298                 while ($dataFile = $dirInstance->readDirectoryExcept(array(".", ".."))) {
 299                         // Generate FQFN for testing
 300                         $fqfn = sprintf("%s/%s", $pathName, $dataFile);
 301                         $this->setLastFile($fqfn);
 302
 303                         // Get instance for file handler
 304                         $inputHandler = $this->getIOInstance();
 305
 306                         // Try to read from it. This makes it sure that the file is
 307                         // readable and a valid database file
 308                         $this->setLastFileContents($inputHandler->loadFileContents($fqfn));
 309
 310                         // Extract filename (= unique ID) from it
 311                         $ID = substr(basename($fqfn), 0, -(strlen($this->getFileExtension()) + 1));
 312
 313                         // Is this the required unique ID?
 314                         if ($ID == $pathFile[1]) {
 315                                 // Okay, already in use!
 316                                 $isUsed = true;
 317                         }
 318                 }
 319
 320                 // Close the directory handler
 321                 $dirInstance->closeDirectory();
 322
 323                 // Now the same for the file...
 324                 return $isUsed;
 325         }
 326
 327         /**
 328          * Getter for the file IO instance
 329          *
 330          *�@return    $ioInstance     An instance for IO operations
 331          * @see         FileIOHandler   The concrete handler for IO operations
 332          */
 333         public final function getIOInstance () {
 334                 return $this->ioInstance;
 335         }
 336
 337         /**
 338          * Setter for the file IO instance
 339          *
 340          * @param               $ioInstance     An instance for IO operations (should be
 341          *                                              FileIOHandler)
 342          * @return      void
 343          */
 344         public final function setIOInstance (FileIOHandler $ioInstance) {
 345                 $this->ioInstance = $ioInstance;
 346         }
 347
 348         /**
 349          * Setter for the last read file
 350          *
 351          * @param               $fqfn   The FQFN of the last read file
 352          * @return      void
 353          */
 354         private function setLastFile ($fqfn) {
 355                 // Cast string
 356                 $fqfn = (string) $fqfn;
 357                 $this->lastFile = $fqfn;
 358         }
 359
 360         /**
 361          * Getter for last read file
 362          *
 363          * @return      $lastFile               The last read file's name with full path
 364          */
 365         public final function getLastFile () {
 366                 return $this->lastFile;
 367         }
 368
 369         /**
 370          * Setter for contents of the last read file
 371          *
 372          * @param               $contents               An array with header and data elements
 373          * @return      void
 374          */
 375         private function setLastFileContents ($contents) {
 376                 // Cast array
 377                 $contents = (array) $contents;
 378                 $this->lastContents = $contents;
 379         }
 380
 381         /**
 382          * Getter for last read file's content as an array
 383          *
 384          * @return      $lastContent    The array with elements 'header' and 'data'.
 385          */
 386         public final function getLastContents () {
 387                 return $this->lastContents;
 388         }
 389
 390         /**
 391          * Get cached (last fetched) data from the local file database
 392          *
 393          * @param               $uniqueID               The ID number for looking up the data
 394          * @return      $object         The restored object from the maybe compressed
 395          *                                              serialized data
 396          * @throws      MismatchingCompressorsException If the compressor from
 397          *                                                                              the loaded file
 398          *                                                                              mismatches with the
 399          *                                                                              current used one.
 400          * @throws      NullPointerException                    If the restored object
 401          *                                                                              is null
 402          * @throws      NoObjectException                               If the restored "object"
 403          *                                                                              is not an object instance
 404          * @throws      MissingMethodException                  If the required method
 405          *                                                                              toString() is missing
 406          */
 407         public function getObjectFromCachedData ($uniqueID) {
 408                 // Get instance for file handler
 409                 $inputHandler = $this->getIOInstance();
 410
 411                 // Get last file's name and contents
 412                 $fqfn = $this->repairFQFN($this->getLastFile(), $uniqueID);
 413                 $contents = $this->repairContents($this->getLastContents(), $fqfn);
 414
 415                 // Let's decompress it. First we need the instance
 416                 $compressInstance = $this->getCompressorChannel();
 417
 418                 // Is the compressor's extension the same as the one from the data?
 419                 if ($compressInstance->getCompressorExtension() != $contents['header'][0]) {
 420                         /**
 421                          * @todo        For now we abort here but later we need to make this a little more dynamic.
 422                          */
 423                         throw new MismatchingCompressorsException(array($this, $contents['header'][0], $fqfn, $compressInstance->getCompressorExtension()), self::EXCEPTION_MISMATCHING_COMPRESSORS);
 424                 }
 425
 426                 // Decompress the data now
 427                 $serialized = $compressInstance->getCompressor()->decompressStream($contents['data']);
 428
 429                 // And unserialize it...
 430                 $object = unserialize($serialized);
 431
 432                 // This must become a valid object, so let's check it...
 433                 if (is_null($object)) {
 434                         // Is null, throw exception
 435                         throw new NullPointerException($object, self::EXCEPTION_IS_NULL_POINTER);
 436                 } elseif (!is_object($object)) {
 437                         // Is not an object, throw exception
 438                         throw new NoObjectException($object, self::EXCEPTION_IS_NO_OBJECT);
 439                 } elseif (!method_exists($object, '__toString')) {
 440                         // A highly required method was not found... :-(
 441                         throw new MissingMethodException(array($object, '__toString'), self::EXCEPTION_MISSING_METHOD);
 442                 }
 443
 444                 // And return the object
 445                 return $object;
 446         }
 447
 448         /**
 449          * Private method for re-gathering (repairing) the FQFN
 450          *
 451          * @param               $fqfn           The current FQFN we shall validate
 452          * @param               $uniqueID               The unique ID number
 453          * @return      $fqfn           The repaired FQFN when it is empty
 454          * @throws      NoArrayCreatedException         If explode() has not
 455          *                                                                      created an array
 456          * @throws      InvalidArrayCountException      If the array count is not
 457          *                                                                      as the expected
 458          */
 459         private function repairFQFN ($fqfn, $uniqueID) {
 460                 // Cast both strings
 461                 $fqfn     = (string) $fqfn;
 462                 $uniqueID = (string) $uniqueID;
 463
 464                 // Is there pre-cached data available?
 465                 if (empty($fqfn)) {
 466                         // Split the unique ID up in path and file name
 467                         $pathFile = explode("@", $uniqueID);
 468
 469                         // Are there two elements? Index 0 is the path, 1 the file name + global extension
 470                         if (!is_array($pathFile)) {
 471                                 // No array found
 472                                 throw new NoArrayCreatedException(array($this, "pathFile"), self::EXCEPTION_ARRAY_EXPECTED);
 473                         } elseif (count($pathFile) != 2) {
 474                                 // Invalid ID returned!
 475                                 throw new InvalidArrayCountException(array($this, "pathFile", count($pathFile), 2), self::EXCEPTION_ARRAY_HAS_INVALID_COUNT);
 476                         }
 477
 478                         // Create full path name
 479                         $pathName = $this->getSavePath() . $pathFile[0];
 480
 481                         // Nothing cached, so let's create a FQFN first
 482                         $fqfn = sprintf("%s/%s.%s", $pathName, $pathFile[1], $this->getFileExtension());
 483                         $this->setLastFile($fqfn);
 484                 }
 485
 486                 // Return repaired FQFN
 487                 return $fqfn;
 488         }
 489
 490         /**
 491          * Private method for re-gathering the contents of a given file
 492          *
 493          * @param               $contents               The (maybe) already cached contents as an array
 494          * @param               $fqfn           The current FQFN we shall validate
 495          * @return      $contents               The repaired contents from the given file
 496          */
 497         private function repairContents ($contents, $fqfn) {
 498                 // Is there some content and header (2 indexes) in?
 499                 if ((!is_array($contents)) || (count($contents) != 2) || (!isset($contents['header'])) || (!isset($contents['data']))) {
 500                         // No content found so load the file again
 501                         $contents = $inputHandler->loadFileContents($fqfn);
 502
 503                         // And remember all data for later usage
 504                         $this->setLastContents($contents);
 505                 }
 506
 507                 // Return the repaired contents
 508                 return $contents;
 509         }
 510
 511         /* DUMMY */ public final function loadObject () {}
 512 }
 513
 514 // [EOF]
 515 ?>