inc/classes/main/stacker/file/class_BaseFileStack.php

   1 <?php
   2 /**
   3  * A general file-based stack class
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2013 Core Developer Team
   8  * @license             GNU GPL 3.0 or any newer version
   9  * @link                http://www.ship-simu.org
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24 class BaseFileStack extends BaseStacker {
  25         /**
  26          * Magic for this stack
  27          */
  28         const STACK_MAGIC = 'STACKv0.1';
  29
  30         /**
  31          * Separator for header data
  32          */
  33         const SEPARATOR_HEADER_DATA = 0x01;
  34
  35         /**
  36          * Separator header->entries
  37          */
  38         const SEPARATOR_HEADER_ENTRIES = 0x02;
  39
  40         /**
  41          * Separator hash->name
  42          */
  43         const SEPARATOR_HASH_NAME = 0x03;
  44
  45         /**
  46          * Length of name
  47          */
  48         const LENGTH_NAME = 10;
  49
  50         /**
  51          * Protected constructor
  52          *
  53          * @param       $className      Name of the class
  54          * @return      void
  55          */
  56         protected function __construct ($className) {
  57                 // Call parent constructor
  58                 parent::__construct($className);
  59
  60                 // Calculate header size
  61                 $this->setHeaderSize(
  62                         strlen(self::STACK_MAGIC) +
  63                         strlen(self::SEPARATOR_HEADER_DATA) +
  64                         self::LENGTH_COUNT +
  65                         strlen(self::SEPARATOR_HEADER_DATA) +
  66                         self::LENGTH_POSITION +
  67                         strlen(self::SEPARATOR_HEADER_ENTRIES)
  68                 );
  69
  70                 // Init counters and gaps array
  71                 $this->initCountersGapsArray();
  72         }
  73
  74         /**
  75          * Reads the file header
  76          *
  77          * @return      void
  78          */
  79         protected function readFileHeader () {
  80                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
  81
  82                 // First rewind to beginning as the header sits at the beginning ...
  83                 $this->getIteratorInstance()->rewind();
  84
  85                 // Then read it (see constructor for calculation)
  86                 $data = $this->getIteratorInstance()->read($this->getHeaderSize());
  87                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Read %d bytes (%d wanted).', __METHOD__, __LINE__, strlen($data), $this->getHeaderSize()));
  88
  89                 // Have all requested bytes been read?
  90                 assert(strlen($data) == $this->getHeaderSize());
  91                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
  92
  93                 // Last character must be the separator
  94                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] data(-1)=%s', __METHOD__, __LINE__, dechex(ord(substr($data, -1, 1)))));
  95                 assert(substr($data, -1, 1) == chr(self::SEPARATOR_HEADER_ENTRIES));
  96                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
  97
  98                 // Okay, then remove it
  99                 $data = substr($data, 0, -1);
 100
 101                 // And update seek position
 102                 $this->updateSeekPosition();
 103
 104                 /*
 105                  * Now split it:
 106                  *
 107                  * 0 => magic
 108                  * 1 => total entries
 109                  * 2 => current seek position
 110                  */
 111                 $header = explode(chr(self::SEPARATOR_HEADER_DATA), $data);
 112
 113                 // Set header here
 114                 $this->setHeader($header);
 115
 116                 // Check if the array has only 3 elements
 117                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] header(%d)=%s', __METHOD__, __LINE__, count($header), print_r($header, TRUE)));
 118                 assert(count($header) == 3);
 119                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 120
 121                 // Check magic
 122                 assert($header[0] == self::STACK_MAGIC);
 123                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 124
 125                 // Check length of count and seek position
 126                 assert(strlen($header[1]) == self::LENGTH_COUNT);
 127                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 128                 assert(strlen($header[2]) == self::LENGTH_POSITION);
 129                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Passed assert().', __METHOD__, __LINE__));
 130
 131                 // Decode count and seek position
 132                 $header[1] = hex2bin($header[1]);
 133                 $header[2] = hex2bin($header[2]);
 134
 135                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 136         }
 137
 138         /**
 139          * Flushes the file header
 140          *
 141          * @return      void
 142          */
 143         protected function flushFileHeader () {
 144                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 145
 146                 // Put all informations together
 147                 $header = sprintf('%s%s%s%s%s%s',
 148                         // Magic
 149                         self::STACK_MAGIC,
 150
 151                         // Separator magic<->count
 152                         chr(self::SEPARATOR_HEADER_DATA),
 153
 154                         // Total entries (will be zero) and pad it to 20 chars
 155                         str_pad($this->dec2hex($this->getCounter()), self::LENGTH_COUNT, '0', STR_PAD_LEFT),
 156
 157                         // Separator count<->seek position
 158                         chr(self::SEPARATOR_HEADER_DATA),
 159
 160                         // Position (will be zero)
 161                         str_pad($this->dec2hex($this->getSeekPosition(), 2), self::LENGTH_POSITION, '0', STR_PAD_LEFT),
 162
 163                         // Separator position<->entries
 164                         chr(self::SEPARATOR_HEADER_ENTRIES)
 165                 );
 166
 167                 // Write it to disk (header is always at seek position 0)
 168                 $this->writeData(0, $header, FALSE);
 169
 170                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 171         }
 172
 173         /**
 174          * Analyzes entries in stack file. This will count all found (and valid)
 175          * entries, mark invalid as damaged and count gaps ("fragmentation"). If
 176          * only gaps are found, the file is considered as "virgin" (no entries).
 177          *
 178          * @return      void
 179          */
 180         private function analyzeFile () {
 181                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] CALLED!', __METHOD__, __LINE__));
 182
 183                 // Make sure the file is initialized
 184                 assert($this->isFileInitialized());
 185
 186                 // Init counters and gaps array
 187                 $this->initCountersGapsArray();
 188
 189                 // Output message (as this may take some time)
 190                 self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] Analyzing file structure ... (this may take some time)', __METHOD__, __LINE__));
 191
 192                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput(sprintf('[%s:%d:] EXIT!', __METHOD__, __LINE__));
 193         }
 194
 195         /**
 196          * Initializes this file-based stack.
 197          *
 198          * @param       $fileName       File name of this stack
 199          * @param       $type           Type of this stack (e.g. url_source for URL sources)
 200          * @return      void
 201          * @todo        Currently the stack file is not cached, please implement a memory-handling class and if enough RAM is found, cache the whole stack file.
 202          */
 203         protected function initFileStack ($fileName, $type) {
 204                 // Get a file i/o pointer instance for stack file
 205                 $fileInstance = ObjectFactory::createObjectByConfiguredName('stack_file_class', array($fileName));
 206
 207                 // Get iterator instance
 208                 $iteratorInstance = ObjectFactory::createObjectByConfiguredName('file_io_iterator_class', array($fileInstance));
 209
 210                 // Is the instance implementing the right interface?
 211                 assert($iteratorInstance instanceof SeekableWritableFileIterator);
 212
 213                 // Set iterator here
 214                 $this->setIteratorInstance($iteratorInstance);
 215
 216                 // Is the file's header initialized?
 217                 if (!$this->isFileHeaderInitialized()) {
 218                         // No, then create it (which may pre-allocate the stack)
 219                         $this->createFileHeader();
 220
 221                         // And pre-allocate a bit
 222                         $this->preAllocateFile('file_stack');
 223                 } // END - if
 224
 225                 // Load the file header
 226                 $this->readFileHeader();
 227
 228                 // Count all entries in file
 229                 $this->analyzeFile();
 230
 231                 /*
 232                  * Get stack index instance. This can be used for faster
 233                  * "defragmentation" and startup.
 234                  */
 235                 $indexInstance = FileStackIndexFactory::createFileStackIndexInstance($fileName, $type);
 236
 237                 // And set it here
 238                 $this->setIndexInstance($indexInstance);
 239         }
 240
 241         /**
 242          * Calculates minimum length for one entry
 243          *
 244          * @return      $length         Minimum length for one entry
 245          */
 246         protected function caluclateMinimumFileEntryLength () {
 247                 // Calulcate it
 248                 $length = self::getHashLength() + strlen(self::SEPARATOR_HASH_NAME) + self::LENGTH_NAME + 1;
 249
 250                 // Return it
 251                 return $length;
 252         }
 253
 254         /**
 255          * Adds a value to given stack
 256          *
 257          * @param       $stackerName    Name of the stack
 258          * @param       $value                  Value to add to this stacker
 259          * @return      void
 260          * @throws      FullStackerException    If the stack is full
 261          */
 262         protected function addValue ($stackerName, $value) {
 263                 // Do some tests
 264                 if ($this->isStackFull($stackerName)) {
 265                         // Stacker is full
 266                         throw new FullStackerException(array($this, $stackerName, $value), self::EXCEPTION_STACKER_IS_FULL);
 267                 } // END - if
 268
 269                 // Now add the value to the stack
 270                 $this->partialStub('stackerName=' . $stackerName . ',value[]=' . gettype($value));
 271         }
 272
 273         /**
 274          * Get last value from named stacker
 275          *
 276          * @param       $stackerName    Name of the stack
 277          * @return      $value                  Value of last added value
 278          * @throws      EmptyStackerException   If the stack is empty
 279          */
 280         protected function getLastValue ($stackerName) {
 281                 // Is the stack not yet initialized or full?
 282                 if ($this->isStackEmpty($stackerName)) {
 283                         // Throw an exception
 284                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 285                 } // END - if
 286
 287                 // Now get the last value
 288                 $this->partialStub('stackerName=' . $stackerName);
 289                 $value = NULL;
 290
 291                 // Return it
 292                 return $value;
 293         }
 294
 295         /**
 296          * Get first value from named stacker
 297          *
 298          * @param       $stackerName    Name of the stack
 299          * @return      $value                  Value of last added value
 300          * @throws      EmptyStackerException   If the stack is empty
 301          */
 302         protected function getFirstValue ($stackerName) {
 303                 // Is the stack not yet initialized or full?
 304                 if ($this->isStackEmpty($stackerName)) {
 305                         // Throw an exception
 306                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 307                 } // END - if
 308
 309                 // Now get the first value
 310                 $this->partialStub('stackerName=' . $stackerName);
 311                 $value = NULL;
 312
 313                 // Return it
 314                 return $value;
 315         }
 316
 317         /**
 318          * "Pops" last entry from stack
 319          *
 320          * @param       $stackerName    Name of the stack
 321          * @return      $value                  Value "poped" from array
 322          * @throws      EmptyStackerException   If the stack is empty
 323          */
 324         protected function popLast ($stackerName) {
 325                 // Is the stack not yet initialized or full?
 326                 if ($this->isStackEmpty($stackerName)) {
 327                         // Throw an exception
 328                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 329                 } // END - if
 330
 331                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 332                 $this->partialStub('stackerName=' . $stackerName);
 333                 return NULL;
 334         }
 335
 336         /**
 337          * "Pops" first entry from stack
 338          *
 339          * @param       $stackerName    Name of the stack
 340          * @return      $value                  Value "shifted" from array
 341          * @throws      EmptyStackerException   If the named stacker is empty
 342          */
 343         protected function popFirst ($stackerName) {
 344                 // Is the stack not yet initialized or full?
 345                 if ($this->isStackEmpty($stackerName)) {
 346                         // Throw an exception
 347                         throw new EmptyStackerException(array($this, $stackerName), self::EXCEPTION_STACKER_IS_EMPTY);
 348                 } // END - if
 349
 350                 // Now, remove the last entry, we don't care about the return value here, see elseif() block above
 351                 $this->partialStub('stackerName=' . $stackerName);
 352                 return NULL;
 353         }
 354
 355         /**
 356          * Checks whether the given stack is full
 357          *
 358          * @param       $stackerName    Name of the stack
 359          * @return      $isFull                 Whether the stack is full
 360          */
 361         protected function isStackFull ($stackerName) {
 362                 // File-based stacks will only run full if the disk space is low.
 363                 // @TODO Please implement this, returning FALSE
 364                 $isFull = FALSE;
 365
 366                 // Return result
 367                 return $isFull;
 368         }
 369
 370         /**
 371          * Checks whether the given stack is empty
 372          *
 373          * @param       $stackerName            Name of the stack
 374          * @return      $isEmpty                        Whether the stack is empty
 375          * @throws      NoStackerException      If given stack is missing
 376          */
 377         public function isStackEmpty ($stackerName) {
 378                 // So, is the stack empty?
 379                 $isEmpty = (($this->getStackCount($stackerName)) == 0);
 380
 381                 // Return result
 382                 return $isEmpty;
 383         }
 384
 385         /**
 386          * Initializes given stacker
 387          *
 388          * @param       $stackerName    Name of the stack
 389          * @param       $forceReInit    Force re-initialization
 390          * @return      void
 391          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 392          */
 393         public function initStack ($stackerName, $forceReInit = FALSE) {
 394                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 395         }
 396
 397         /**
 398          * Initializes all stacks
 399          *
 400          * @return      void
 401          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 402          */
 403         public function initStacks (array $stacks, $forceReInit = FALSE) {
 404                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 405         }
 406
 407         /**
 408          * Checks whether the given stack is initialized (set in array $stackers)
 409          *
 410          * @param       $stackerName    Name of the stack
 411          * @return      $isInitialized  Whether the stack is initialized
 412          * @throws      UnsupportedOperationException   This method is not (and maybe never will be) supported
 413          */
 414         public function isStackInitialized ($stackerName) {
 415                 throw new UnsupportedOperationException(array($this, __FUNCTION__, $this->getIteratorInstance()->getPointerInstance()), self::EXCEPTION_UNSPPORTED_OPERATION);
 416         }
 417
 418         /**
 419          * Getter for size of given stack (array count)
 420          *
 421          * @param       $stackerName    Name of the stack
 422          * @return      $count                  Size of stack (array count)
 423          */
 424         public function getStackCount ($stackerName) {
 425                 // Now, simply return the found count value, this must be up-to-date then!
 426                 return $this->getCounter();
 427         }
 428 }
 429
 430 // [EOF]
 431 ?>