InputOutputPointer is the right interface.
[core.git] / 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 stack file instance
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 ?>