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MediumSpecificBagOStuff.php
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1 <?php
24 use Wikimedia\WaitConditionLoop;
25 
34 abstract class MediumSpecificBagOStuff extends BagOStuff {
36  protected $locks = [];
38  protected $segmentationSize;
41 
43  protected $maxLockSendDelay = 0.05;
44 
46  private $duplicateKeyLookups = [];
48  private $reportDupes = false;
50  private $dupeTrackScheduled = false;
51 
53  private const SEGMENT_COMPONENT = 'segment';
54 
56  protected const PASS_BY_REF = -1;
57 
58  protected const METRIC_OP_GET = 'get';
59  protected const METRIC_OP_SET = 'set';
60  protected const METRIC_OP_DELETE = 'delete';
61  protected const METRIC_OP_CHANGE_TTL = 'change_ttl';
62  protected const METRIC_OP_ADD = 'add';
63  protected const METRIC_OP_INCR = 'incr';
64  protected const METRIC_OP_DECR = 'decr';
65  protected const METRIC_OP_CAS = 'cas';
66 
67  protected const LOCK_RCLASS = 0;
68  protected const LOCK_DEPTH = 1;
69  protected const LOCK_TIME = 2;
70  protected const LOCK_EXPIRY = 3;
71 
88  public function __construct( array $params = [] ) {
89  parent::__construct( $params );
90 
91  if ( !empty( $params['reportDupes'] ) && $this->asyncHandler ) {
92  $this->reportDupes = true;
93  }
94 
95  // Default to 8MiB if segmentationSize is not set
96  $this->segmentationSize = $params['segmentationSize'] ?? 8388608;
97  // Default to 64MiB if segmentedValueMaxSize is not set
98  $this->segmentedValueMaxSize = $params['segmentedValueMaxSize'] ?? 67108864;
99  }
100 
114  public function get( $key, $flags = 0 ) {
115  $this->trackDuplicateKeys( $key );
116 
117  return $this->resolveSegments( $key, $this->doGet( $key, $flags ) );
118  }
119 
124  private function trackDuplicateKeys( $key ) {
125  if ( !$this->reportDupes ) {
126  return;
127  }
128 
129  if ( !isset( $this->duplicateKeyLookups[$key] ) ) {
130  // Track that we have seen this key. This N-1 counting style allows
131  // easy filtering with array_filter() later.
132  $this->duplicateKeyLookups[$key] = 0;
133  } else {
134  $this->duplicateKeyLookups[$key] += 1;
135 
136  if ( $this->dupeTrackScheduled === false ) {
137  $this->dupeTrackScheduled = true;
138  // Schedule a callback that logs keys processed more than once by get().
139  call_user_func( $this->asyncHandler, function () {
140  $dups = array_filter( $this->duplicateKeyLookups );
141  foreach ( $dups as $key => $count ) {
142  $this->logger->warning(
143  'Duplicate get(): "{key}" fetched {count} times',
144  // Count is N-1 of the actual lookup count
145  [ 'key' => $key, 'count' => $count + 1, ]
146  );
147  }
148  } );
149  }
150  }
151  }
152 
163  abstract protected function doGet( $key, $flags = 0, &$casToken = null );
164 
174  public function set( $key, $value, $exptime = 0, $flags = 0 ) {
175  $entry = $this->makeValueOrSegmentList( $key, $value, $exptime, $flags, $ok );
176  // Only when all segments (if any) are stored should the main key be changed
177  return $ok ? $this->doSet( $key, $entry, $exptime, $flags ) : false;
178  }
179 
189  abstract protected function doSet( $key, $value, $exptime = 0, $flags = 0 );
190 
202  public function delete( $key, $flags = 0 ) {
203  if ( !$this->fieldHasFlags( $flags, self::WRITE_PRUNE_SEGMENTS ) ) {
204  return $this->doDelete( $key, $flags );
205  }
206 
207  $mainValue = $this->doGet( $key, self::READ_LATEST );
208  if ( !$this->doDelete( $key, $flags ) ) {
209  return false;
210  }
211 
212  if ( !SerializedValueContainer::isSegmented( $mainValue ) ) {
213  // no segments to delete
214  return true;
215  }
216 
217  $orderedKeys = array_map(
218  function ( $segmentHash ) use ( $key ) {
219  return $this->makeGlobalKey( self::SEGMENT_COMPONENT, $key, $segmentHash );
220  },
222  );
223 
224  return $this->deleteMulti( $orderedKeys, $flags & ~self::WRITE_PRUNE_SEGMENTS );
225  }
226 
234  abstract protected function doDelete( $key, $flags = 0 );
235 
236  public function add( $key, $value, $exptime = 0, $flags = 0 ) {
237  $entry = $this->makeValueOrSegmentList( $key, $value, $exptime, $flags, $ok );
238  // Only when all segments (if any) are stored should the main key be changed
239  return $ok ? $this->doAdd( $key, $entry, $exptime, $flags ) : false;
240  }
241 
251  abstract protected function doAdd( $key, $value, $exptime = 0, $flags = 0 );
252 
269  public function merge( $key, callable $callback, $exptime = 0, $attempts = 10, $flags = 0 ) {
270  return $this->mergeViaCas( $key, $callback, $exptime, $attempts, $flags );
271  }
272 
282  final protected function mergeViaCas( $key, callable $callback, $exptime, $attempts, $flags ) {
283  $attemptsLeft = $attempts;
284  do {
285  $token = self::PASS_BY_REF;
286  // Get the old value and CAS token from cache
287  $watchPoint = $this->watchErrors();
288  $currentValue = $this->resolveSegments(
289  $key,
290  $this->doGet( $key, $flags, $token )
291  );
292  if ( $this->getLastError( $watchPoint ) ) {
293  // Don't spam slow retries due to network problems (retry only on races)
294  $this->logger->warning(
295  __METHOD__ . ' failed due to read I/O error on get() for {key}.',
296  [ 'key' => $key ]
297  );
298  $success = false;
299  break;
300  }
301 
302  // Derive the new value from the old value
303  $value = $callback( $this, $key, $currentValue, $exptime );
304  $keyWasNonexistant = ( $currentValue === false );
305  $valueMatchesOldValue = ( $value === $currentValue );
306  // free RAM in case the value is large
307  unset( $currentValue );
308 
309  $watchPoint = $this->watchErrors();
310  if ( $value === false || $exptime < 0 ) {
311  // do nothing
312  $success = true;
313  } elseif ( $valueMatchesOldValue && $attemptsLeft !== $attempts ) {
314  // recently set by another thread to the same value
315  $success = true;
316  } elseif ( $keyWasNonexistant ) {
317  // Try to create the key, failing if it gets created in the meantime
318  $success = $this->add( $key, $value, $exptime, $flags );
319  } else {
320  // Try to update the key, failing if it gets changed in the meantime
321  $success = $this->cas( $token, $key, $value, $exptime, $flags );
322  }
323  if ( $this->getLastError( $watchPoint ) ) {
324  // Don't spam slow retries due to network problems (retry only on races)
325  $this->logger->warning(
326  __METHOD__ . ' failed due to write I/O error for {key}.',
327  [ 'key' => $key ]
328  );
329  $success = false;
330  break;
331  }
332 
333  } while ( !$success && --$attemptsLeft );
334 
335  return $success;
336  }
337 
348  protected function cas( $casToken, $key, $value, $exptime = 0, $flags = 0 ) {
349  if ( $casToken === null ) {
350  $this->logger->warning(
351  __METHOD__ . ' got empty CAS token for {key}.',
352  [ 'key' => $key ]
353  );
354 
355  // caller may have meant to use add()?
356  return false;
357  }
358 
359  $entry = $this->makeValueOrSegmentList( $key, $value, $exptime, $flags, $ok );
360  // Only when all segments (if any) are stored should the main key be changed
361  return $ok ? $this->doCas( $casToken, $key, $entry, $exptime, $flags ) : false;
362  }
363 
374  protected function doCas( $casToken, $key, $value, $exptime = 0, $flags = 0 ) {
375  // @TODO: the use of lock() assumes that all other relevant sets() use a lock
376  if ( !$this->lock( $key, 0 ) ) {
377  // non-blocking
378  return false;
379  }
380 
381  $curCasToken = self::PASS_BY_REF;
382  $watchPoint = $this->watchErrors();
383  $exists = ( $this->doGet( $key, self::READ_LATEST, $curCasToken ) !== false );
384  if ( $this->getLastError( $watchPoint ) ) {
385  // Fail if the old CAS token could not be read
386  $success = false;
387  $this->logger->warning(
388  __METHOD__ . ' failed due to write I/O error for {key}.',
389  [ 'key' => $key ]
390  );
391  } elseif ( $exists && $this->tokensMatch( $casToken, $curCasToken ) ) {
392  $success = $this->doSet( $key, $value, $exptime, $flags );
393  } else {
394  // mismatched or failed
395  $success = false;
396  $this->logger->info(
397  __METHOD__ . ' failed due to race condition for {key}.',
398  [ 'key' => $key, 'key_exists' => $exists ]
399  );
400  }
401 
402  $this->unlock( $key );
403 
404  return $success;
405  }
406 
412  final protected function tokensMatch( $value, $otherValue ) {
413  $type = gettype( $value );
414  // Ideally, tokens are counters, timestamps, hashes, or serialized PHP values.
415  // However, some classes might use the PHP values themselves.
416  if ( $type !== gettype( $otherValue ) ) {
417  return false;
418  }
419  // Serialize both tokens to strictly compare objects or arrays (which might objects
420  // nested inside). Note that this will not apply if integer/string CAS tokens are used.
421  if ( $type === 'array' || $type === 'object' ) {
422  return ( serialize( $value ) === serialize( $otherValue ) );
423  }
424  // For string/integer tokens, use a simple comparison
425  return ( $value === $otherValue );
426  }
427 
445  public function changeTTL( $key, $exptime = 0, $flags = 0 ) {
446  return $this->doChangeTTL( $key, $exptime, $flags );
447  }
448 
455  protected function doChangeTTL( $key, $exptime, $flags ) {
456  // @TODO: the use of lock() assumes that all other relevant sets() use a lock
457  if ( !$this->lock( $key, 0 ) ) {
458  return false;
459  }
460 
461  $expiry = $this->getExpirationAsTimestamp( $exptime );
462  $delete = ( $expiry != self::TTL_INDEFINITE && $expiry < $this->getCurrentTime() );
463 
464  // Use doGet() to avoid having to trigger resolveSegments()
465  $blob = $this->doGet( $key, self::READ_LATEST );
466  if ( $blob ) {
467  if ( $delete ) {
468  $ok = $this->doDelete( $key, $flags );
469  } else {
470  $ok = $this->doSet( $key, $blob, $exptime, $flags );
471  }
472  } else {
473  $ok = false;
474  }
475 
476  $this->unlock( $key );
477 
478  return $ok;
479  }
480 
481  public function incrWithInit( $key, $exptime, $step = 1, $init = null, $flags = 0 ) {
482  $step = (int)$step;
483  $init = is_int( $init ) ? $init : $step;
484 
485  return $this->doIncrWithInit( $key, $exptime, $step, $init, $flags );
486  }
487 
496  abstract protected function doIncrWithInit( $key, $exptime, $step, $init, $flags );
497 
505  public function lock( $key, $timeout = 6, $exptime = 6, $rclass = '' ) {
506  $exptime = min( $exptime ?: INF, self::TTL_DAY );
507 
508  $acquired = false;
509 
510  if ( isset( $this->locks[$key] ) ) {
511  // Already locked; avoid deadlocks and allow lock reentry if specified
512  if ( $rclass != '' && $this->locks[$key][self::LOCK_RCLASS] === $rclass ) {
513  ++$this->locks[$key][self::LOCK_DEPTH];
514  $acquired = true;
515  }
516  } else {
517  // Not already locked; acquire a lock on the backend
518  $lockTsUnix = $this->doLock( $key, $timeout, $exptime );
519  if ( $lockTsUnix !== null ) {
520  $this->locks[$key] = [
521  self::LOCK_RCLASS => $rclass,
522  self::LOCK_DEPTH => 1,
523  self::LOCK_TIME => $lockTsUnix,
524  self::LOCK_EXPIRY => $lockTsUnix + $exptime
525  ];
526  $acquired = true;
527  }
528  }
529 
530  return $acquired;
531  }
532 
541  protected function doLock( $key, $timeout, $exptime ) {
542  $lockTsUnix = null;
543 
544  $fname = __METHOD__;
545  $loop = new WaitConditionLoop(
546  function () use ( $key, $exptime, $fname, &$lockTsUnix ) {
547  $watchPoint = $this->watchErrors();
548  if ( $this->add( $this->makeLockKey( $key ), 1, $exptime ) ) {
549  $lockTsUnix = microtime( true );
550 
551  return WaitConditionLoop::CONDITION_REACHED;
552  } elseif ( $this->getLastError( $watchPoint ) ) {
553  $this->logger->warning(
554  "$fname failed due to I/O error for {key}.",
555  [ 'key' => $key ]
556  );
557 
558  return WaitConditionLoop::CONDITION_ABORTED;
559  }
560 
561  return WaitConditionLoop::CONDITION_CONTINUE;
562  },
563  $timeout
564  );
565  $code = $loop->invoke();
566 
567  if ( $code === $loop::CONDITION_TIMED_OUT ) {
568  $this->logger->warning(
569  "$fname failed due to timeout for {key}.",
570  [ 'key' => $key, 'timeout' => $timeout ]
571  );
572  }
573 
574  return $lockTsUnix;
575  }
576 
583  public function unlock( $key ) {
584  $released = false;
585 
586  if ( isset( $this->locks[$key] ) ) {
587  if ( --$this->locks[$key][self::LOCK_DEPTH] > 0 ) {
588  $released = true;
589  } else {
590  $released = $this->doUnlock( $key );
591  unset( $this->locks[$key] );
592  if ( !$released ) {
593  $this->logger->warning(
594  __METHOD__ . ' failed to release lock for {key}.',
595  [ 'key' => $key ]
596  );
597  }
598  }
599  } else {
600  $this->logger->warning(
601  __METHOD__ . ' no lock to release for {key}.',
602  [ 'key' => $key ]
603  );
604  }
605 
606  return $released;
607  }
608 
615  protected function doUnlock( $key ) {
616  $released = false;
617 
618  // Estimate the remaining TTL of the lock key
619  $curTTL = $this->locks[$key][self::LOCK_EXPIRY] - $this->getCurrentTime();
620 
621  // Check the risk of race conditions for key deletion
622  if ( $this->getQoS( self::ATTR_DURABILITY ) <= self::QOS_DURABILITY_SCRIPT ) {
623  // Lock (and data) keys use memory specific to this request (e.g. HashBagOStuff)
624  $isSafe = true;
625  } else {
626  // It is unsafe to delete the lock key if there is a serious risk of the key already
627  // being claimed by another thread before the delete operation reaches the backend
628  $isSafe = ( $curTTL > $this->maxLockSendDelay );
629  }
630 
631  if ( $isSafe ) {
632  $released = $this->doDelete( $this->makeLockKey( $key ) );
633  } else {
634  $this->logger->warning(
635  "Lock for {key} held too long ({age} sec).",
636  [ 'key' => $key, 'curTTL' => $curTTL ]
637  );
638  }
639 
640  return $released;
641  }
642 
647  protected function makeLockKey( $key ) {
648  return "$key:lock";
649  }
650 
652  $timestamp,
653  callable $progress = null,
654  $limit = INF,
655  string $tag = null
656  ) {
657  return false;
658  }
659 
666  public function getMulti( array $keys, $flags = 0 ) {
667  $foundByKey = $this->doGetMulti( $keys, $flags );
668 
669  $res = [];
670  foreach ( $keys as $key ) {
671  // Resolve one blob at a time (avoids too much I/O at once)
672  if ( array_key_exists( $key, $foundByKey ) ) {
673  // A value should not appear in the key if a segment is missing
674  $value = $this->resolveSegments( $key, $foundByKey[$key] );
675  if ( $value !== false ) {
676  $res[$key] = $value;
677  }
678  }
679  }
680 
681  return $res;
682  }
683 
690  protected function doGetMulti( array $keys, $flags = 0 ) {
691  $res = [];
692  foreach ( $keys as $key ) {
693  $val = $this->doGet( $key, $flags );
694  if ( $val !== false ) {
695  $res[$key] = $val;
696  }
697  }
698 
699  return $res;
700  }
701 
713  public function setMulti( array $valueByKey, $exptime = 0, $flags = 0 ) {
714  if ( $this->fieldHasFlags( $flags, self::WRITE_ALLOW_SEGMENTS ) ) {
715  throw new InvalidArgumentException( __METHOD__ . ' got WRITE_ALLOW_SEGMENTS' );
716  }
717 
718  return $this->doSetMulti( $valueByKey, $exptime, $flags );
719  }
720 
727  protected function doSetMulti( array $data, $exptime = 0, $flags = 0 ) {
728  $res = true;
729  foreach ( $data as $key => $value ) {
730  $res = $this->doSet( $key, $value, $exptime, $flags ) && $res;
731  }
732 
733  return $res;
734  }
735 
746  public function deleteMulti( array $keys, $flags = 0 ) {
747  if ( $this->fieldHasFlags( $flags, self::WRITE_PRUNE_SEGMENTS ) ) {
748  throw new InvalidArgumentException( __METHOD__ . ' got WRITE_PRUNE_SEGMENTS' );
749  }
750 
751  return $this->doDeleteMulti( $keys, $flags );
752  }
753 
759  protected function doDeleteMulti( array $keys, $flags = 0 ) {
760  $res = true;
761  foreach ( $keys as $key ) {
762  $res = $this->doDelete( $key, $flags ) && $res;
763  }
764  return $res;
765  }
766 
777  public function changeTTLMulti( array $keys, $exptime, $flags = 0 ) {
778  return $this->doChangeTTLMulti( $keys, $exptime, $flags );
779  }
780 
787  protected function doChangeTTLMulti( array $keys, $exptime, $flags = 0 ) {
788  $res = true;
789  foreach ( $keys as $key ) {
790  $res = $this->doChangeTTL( $key, $exptime, $flags ) && $res;
791  }
792 
793  return $res;
794  }
795 
803  final protected function resolveSegments( $key, $mainValue ) {
804  if ( SerializedValueContainer::isUnified( $mainValue ) ) {
805  return $this->unserialize( $mainValue->{SerializedValueContainer::UNIFIED_DATA} );
806  }
807 
808  if ( SerializedValueContainer::isSegmented( $mainValue ) ) {
809  $orderedKeys = array_map(
810  function ( $segmentHash ) use ( $key ) {
811  return $this->makeGlobalKey( self::SEGMENT_COMPONENT, $key, $segmentHash );
812  },
814  );
815 
816  $segmentsByKey = $this->doGetMulti( $orderedKeys );
817 
818  $parts = [];
819  foreach ( $orderedKeys as $segmentKey ) {
820  if ( isset( $segmentsByKey[$segmentKey] ) ) {
821  $parts[] = $segmentsByKey[$segmentKey];
822  } else {
823  // missing segment
824  return false;
825  }
826  }
827 
828  return $this->unserialize( implode( '', $parts ) );
829  }
830 
831  return $mainValue;
832  }
833 
834  final public function addBusyCallback( callable $workCallback ) {
835  wfDeprecated( __METHOD__, '1.39' );
836  }
837 
850  private function useSegmentationWrapper( $value, $flags ) {
851  if (
852  $this->segmentationSize === INF ||
853  !$this->fieldHasFlags( $flags, self::WRITE_ALLOW_SEGMENTS )
854  ) {
855  return false;
856  }
857 
858  if ( is_string( $value ) ) {
859  return ( strlen( $value ) >= $this->segmentationSize );
860  }
861 
862  if ( is_array( $value ) ) {
863  // Expect that the contained value will be one of the first array entries
864  foreach ( array_slice( $value, 0, 4 ) as $v ) {
865  if ( is_string( $v ) && strlen( $v ) >= $this->segmentationSize ) {
866  return true;
867  }
868  }
869  }
870 
871  // Avoid breaking functions for incrementing/decrementing integer key values
872  return false;
873  }
874 
886  final protected function makeValueOrSegmentList( $key, $value, $exptime, $flags, &$ok ) {
887  $entry = $value;
888  $ok = true;
889 
890  if ( $this->useSegmentationWrapper( $value, $flags ) ) {
891  $segmentSize = $this->segmentationSize;
892  $maxTotalSize = $this->segmentedValueMaxSize;
893  $serialized = $this->getSerialized( $value, $key );
894  $size = strlen( $serialized );
895  if ( $size > $maxTotalSize ) {
896  $this->logger->warning(
897  "Value for {key} exceeds $maxTotalSize bytes; cannot segment.",
898  [ 'key' => $key ]
899  );
900  } else {
901  // Split the serialized value into chunks and store them at different keys
902  $chunksByKey = [];
903  $segmentHashes = [];
904  $count = intdiv( $size, $segmentSize ) + ( ( $size % $segmentSize ) ? 1 : 0 );
905  for ( $i = 0; $i < $count; ++$i ) {
906  $segment = substr( $serialized, $i * $segmentSize, $segmentSize );
907  $hash = sha1( $segment );
908  $chunkKey = $this->makeGlobalKey( self::SEGMENT_COMPONENT, $key, $hash );
909  $chunksByKey[$chunkKey] = $segment;
910  $segmentHashes[] = $hash;
911  }
912  $flags &= ~self::WRITE_ALLOW_SEGMENTS;
913  $ok = $this->setMulti( $chunksByKey, $exptime, $flags );
914  $entry = SerializedValueContainer::newSegmented( $segmentHashes );
915  }
916  }
917 
918  return $entry;
919  }
920 
926  final protected function isRelativeExpiration( $exptime ) {
927  return ( $exptime !== self::TTL_INDEFINITE && $exptime < ( 10 * self::TTL_YEAR ) );
928  }
929 
943  final protected function getExpirationAsTimestamp( $exptime ) {
944  if ( $exptime == self::TTL_INDEFINITE ) {
945  return $exptime;
946  }
947 
948  return $this->isRelativeExpiration( $exptime )
949  ? intval( $this->getCurrentTime() + $exptime )
950  : $exptime;
951  }
952 
967  final protected function getExpirationAsTTL( $exptime ) {
968  if ( $exptime == self::TTL_INDEFINITE ) {
969  return $exptime;
970  }
971 
972  return $this->isRelativeExpiration( $exptime )
973  ? $exptime
974  : (int)max( $exptime - $this->getCurrentTime(), 1 );
975  }
976 
983  final protected function isInteger( $value ) {
984  if ( is_int( $value ) ) {
985  return true;
986  } elseif ( !is_string( $value ) ) {
987  return false;
988  }
989 
990  $integer = (int)$value;
991 
992  return ( $value === (string)$integer );
993  }
994 
995  public function makeGlobalKey( $collection, ...$components ) {
996  return $this->makeKeyInternal( self::GLOBAL_KEYSPACE, func_get_args() );
997  }
998 
999  public function makeKey( $collection, ...$components ) {
1000  return $this->makeKeyInternal( $this->keyspace, func_get_args() );
1001  }
1002 
1014  abstract protected function makeKeyInternal( $keyspace, $components );
1015 
1016  protected function convertGenericKey( $key ) {
1017  $components = $this->componentsFromGenericKey( $key );
1018  if ( count( $components ) < 2 ) {
1019  // Legacy key not from makeKey()/makeGlobalKey(); keep it as-is
1020  return $key;
1021  }
1022 
1023  $keyspace = array_shift( $components );
1024 
1025  return $this->makeKeyInternal( $keyspace, $components );
1026  }
1027 
1028  public function getQoS( $flag ) {
1029  return $this->attrMap[$flag] ?? self::QOS_UNKNOWN;
1030  }
1031 
1032  public function getSegmentationSize() {
1033  return $this->segmentationSize;
1034  }
1035 
1036  public function getSegmentedValueMaxSize() {
1037  return $this->segmentedValueMaxSize;
1038  }
1039 
1048  protected function getSerialized( $value, $key ) {
1049  $this->checkValueSerializability( $value, $key );
1050 
1051  return $this->serialize( $value );
1052  }
1053 
1074  private function checkValueSerializability( $value, $key ) {
1075  if ( is_array( $value ) ) {
1076  $this->checkIterableMapSerializability( $value, $key );
1077  } elseif ( is_object( $value ) ) {
1078  // Note that Closure instances count as objects
1079  if ( $value instanceof stdClass ) {
1080  $this->checkIterableMapSerializability( $value, $key );
1081  } elseif ( !( $value instanceof JsonSerializable ) ) {
1082  $this->logger->warning(
1083  "{class} value for '{cachekey}'; serialization is suspect.",
1084  [ 'cachekey' => $key, 'class' => get_class( $value ) ]
1085  );
1086  }
1087  }
1088  }
1089 
1094  private function checkIterableMapSerializability( $value, $key ) {
1095  foreach ( $value as $index => $entry ) {
1096  if ( is_object( $entry ) ) {
1097  // Note that Closure instances count as objects
1098  if (
1099  !( $entry instanceof stdClass ) &&
1100  !( $entry instanceof JsonSerializable )
1101  ) {
1102  $this->logger->warning(
1103  "{class} value for '{cachekey}' at '$index'; serialization is suspect.",
1104  [ 'cachekey' => $key, 'class' => get_class( $entry ) ]
1105  );
1106 
1107  return;
1108  }
1109  }
1110  }
1111  }
1112 
1118  protected function serialize( $value ) {
1119  return is_int( $value ) ? $value : serialize( $value );
1120  }
1121 
1127  protected function unserialize( $value ) {
1128  return $this->isInteger( $value ) ? (int)$value : unserialize( $value );
1129  }
1130 
1134  protected function debug( $text ) {
1135  $this->logger->debug( "{class} debug: $text", [ 'class' => static::class ] );
1136  }
1137 
1145  protected function updateOpStats( string $op, array $keyInfo ) {
1146  $deltasByMetric = [];
1147 
1148  foreach ( $keyInfo as $indexOrKey => $keyOrSizes ) {
1149  if ( is_array( $keyOrSizes ) ) {
1150  $key = $indexOrKey;
1151  list( $sPayloadSize, $rPayloadSize ) = $keyOrSizes;
1152  } else {
1153  $key = $keyOrSizes;
1154  $sPayloadSize = 0;
1155  $rPayloadSize = 0;
1156  }
1157 
1158  // Metric prefix for the cache wrapper and key collection name
1159  $prefix = $this->determineKeyPrefixForStats( $key );
1160 
1161  if ( $op === self::METRIC_OP_GET ) {
1162  // This operation was either a "hit" or "miss" for this key
1163  $name = "{$prefix}.{$op}_" . ( $rPayloadSize === false ? 'miss_rate' : 'hit_rate' );
1164  } else {
1165  // There is no concept of "hit" or "miss" for this operation
1166  $name = "{$prefix}.{$op}_call_rate";
1167  }
1168  $deltasByMetric[$name] = ( $deltasByMetric[$name] ?? 0 ) + 1;
1169 
1170  if ( $sPayloadSize > 0 ) {
1171  $name = "{$prefix}.{$op}_bytes_sent";
1172  $deltasByMetric[$name] = ( $deltasByMetric[$name] ?? 0 ) + $sPayloadSize;
1173  }
1174 
1175  if ( $rPayloadSize > 0 ) {
1176  $name = "{$prefix}.{$op}_bytes_read";
1177  $deltasByMetric[$name] = ( $deltasByMetric[$name] ?? 0 ) + $rPayloadSize;
1178  }
1179  }
1180 
1181  foreach ( $deltasByMetric as $name => $delta ) {
1182  $this->stats->updateCount( $name, $delta );
1183  }
1184  }
1185 }
serialize()
unserialize( $serialized)
wfDeprecated( $function, $version=false, $component=false, $callerOffset=2)
Logs a warning that a deprecated feature was used.
$success
Class representing a cache/ephemeral data store.
Definition: BagOStuff.php:85
fieldHasFlags( $field, $flags)
Definition: BagOStuff.php:612
Storage medium specific cache for storing items (e.g.
doSet( $key, $value, $exptime=0, $flags=0)
Set an item.
int $segmentationSize
Bytes; chunk size of segmented cache values.
cas( $casToken, $key, $value, $exptime=0, $flags=0)
Set an item if the current CAS token matches the provided CAS token.
doDeleteMulti(array $keys, $flags=0)
const PASS_BY_REF
Idiom for doGet() to return extra information by reference.
setMulti(array $valueByKey, $exptime=0, $flags=0)
Batch insertion/replace.
doChangeTTLMulti(array $keys, $exptime, $flags=0)
float $maxLockSendDelay
Seconds; maximum expected seconds for a lock ping to reach the backend.
getExpirationAsTimestamp( $exptime)
Convert an optionally relative timestamp to an absolute time.
getMulti(array $keys, $flags=0)
Get an associative array containing the item for each of the keys that have items.
add( $key, $value, $exptime=0, $flags=0)
Insert an item if it does not already exist.
deleteMulti(array $keys, $flags=0)
Batch deletion.
tokensMatch( $value, $otherValue)
addBusyCallback(callable $workCallback)
Let a callback be run to avoid wasting time on special blocking calls.
getSerialized( $value, $key)
Get the serialized form a value, logging a warning if it involves custom classes.
doSetMulti(array $data, $exptime=0, $flags=0)
doChangeTTL( $key, $exptime, $flags)
makeKey( $collection,... $components)
Make a cache key for the global keyspace and given components.
merge( $key, callable $callback, $exptime=0, $attempts=10, $flags=0)
Merge changes into the existing cache value (possibly creating a new one)
unlock( $key)
Release an advisory lock on a key string.
doGetMulti(array $keys, $flags=0)
Get an associative array containing the item for each of the keys that have items.
doIncrWithInit( $key, $exptime, $step, $init, $flags)
updateOpStats(string $op, array $keyInfo)
array< string, array > $locks
Map of (key => (class LOCK_* constant => value)
doCas( $casToken, $key, $value, $exptime=0, $flags=0)
Set an item if the current CAS token matches the provided CAS token.
doDelete( $key, $flags=0)
Delete an item.
doLock( $key, $timeout, $exptime)
convertGenericKey( $key)
Convert a "generic" reversible cache key into one for this cache.
mergeViaCas( $key, callable $callback, $exptime, $attempts, $flags)
doAdd( $key, $value, $exptime=0, $flags=0)
Insert an item if it does not already exist.
getExpirationAsTTL( $exptime)
Convert an optionally absolute expiry time to a relative time.
resolveSegments( $key, $mainValue)
Get and reassemble the chunks of blob at the given key.
changeTTLMulti(array $keys, $exptime, $flags=0)
Change the expiration of multiple keys that exist.
changeTTL( $key, $exptime=0, $flags=0)
Change the expiration on a key if it exists.
incrWithInit( $key, $exptime, $step=1, $init=null, $flags=0)
Increase the value of the given key (no TTL change) if it exists or create it otherwise.
isInteger( $value)
Check if a value is an integer.
makeGlobalKey( $collection,... $components)
Make a cache key for the default keyspace and given components.
lock( $key, $timeout=6, $exptime=6, $rclass='')
makeValueOrSegmentList( $key, $value, $exptime, $flags, &$ok)
Make the entry to store at a key (inline or segment list), storing any segments.
deleteObjectsExpiringBefore( $timestamp, callable $progress=null, $limit=INF, string $tag=null)
Delete all objects expiring before a certain date.
makeKeyInternal( $keyspace, $components)
Make a cache key for the given keyspace and components.
int $segmentedValueMaxSize
Bytes; maximum total size of a segmented cache value.
doGet( $key, $flags=0, &$casToken=null)
Get an item.
static newSegmented(array $segmentHashList)
foreach( $res as $row) $serialized