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