3 * Helper class for representing operations with transaction support.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
21 * @ingroup FileBackend
22 * @author Aaron Schulz
26 * FileBackend helper class for representing operations.
27 * Do not use this class from places outside FileBackend.
29 * Methods called from FileOpBatch::attempt() should avoid throwing
30 * exceptions at all costs. FileOp objects should be lightweight in order
31 * to support large arrays in memory and serialization.
33 * @ingroup FileBackend
36 abstract class FileOp
{
38 protected $params = array();
39 /** @var FileBackendStore */
42 protected $state = self
::STATE_NEW
; // integer
43 protected $failed = false; // boolean
44 protected $async = false; // boolean
45 protected $useLatest = true; // boolean
46 protected $batchId; // string
48 protected $sourceSha1; // string
49 protected $destSameAsSource; // boolean
51 /* Object life-cycle */
53 const STATE_CHECKED
= 2;
54 const STATE_ATTEMPTED
= 3;
57 * Build a new file operation transaction
59 * @param $backend FileBackendStore
60 * @param $params Array
63 final public function __construct( FileBackendStore
$backend, array $params ) {
64 $this->backend
= $backend;
65 list( $required, $optional ) = $this->allowedParams();
66 foreach ( $required as $name ) {
67 if ( isset( $params[$name] ) ) {
68 $this->params
[$name] = $params[$name];
70 throw new MWException( "File operation missing parameter '$name'." );
73 foreach ( $optional as $name ) {
74 if ( isset( $params[$name] ) ) {
75 $this->params
[$name] = $params[$name];
78 $this->params
= $params;
82 * Set the batch UUID this operation belongs to
84 * @param $batchId string
87 final public function setBatchId( $batchId ) {
88 $this->batchId
= $batchId;
92 * Whether to allow stale data for file reads and stat checks
94 * @param $allowStale bool
97 final public function allowStaleReads( $allowStale ) {
98 $this->useLatest
= !$allowStale;
102 * Get the value of the parameter with the given name
104 * @param $name string
105 * @return mixed Returns null if the parameter is not set
107 final public function getParam( $name ) {
108 return isset( $this->params
[$name] ) ?
$this->params
[$name] : null;
112 * Check if this operation failed precheck() or attempt()
116 final public function failed() {
117 return $this->failed
;
121 * Get a new empty predicates array for precheck()
125 final public static function newPredicates() {
126 return array( 'exists' => array(), 'sha1' => array() );
130 * Get a new empty dependency tracking array for paths read/written to
134 final public static function newDependencies() {
135 return array( 'read' => array(), 'write' => array() );
139 * Update a dependency tracking array to account for this operation
141 * @param $deps Array Prior path reads/writes; format of FileOp::newPredicates()
144 final public function applyDependencies( array $deps ) {
145 $deps['read'] +
= array_fill_keys( $this->storagePathsRead(), 1 );
146 $deps['write'] +
= array_fill_keys( $this->storagePathsChanged(), 1 );
151 * Check if this operation changes files listed in $paths
153 * @param $paths Array Prior path reads/writes; format of FileOp::newPredicates()
156 final public function dependsOn( array $deps ) {
157 foreach ( $this->storagePathsChanged() as $path ) {
158 if ( isset( $deps['read'][$path] ) ||
isset( $deps['write'][$path] ) ) {
159 return true; // "output" or "anti" dependency
162 foreach ( $this->storagePathsRead() as $path ) {
163 if ( isset( $deps['write'][$path] ) ) {
164 return true; // "flow" dependency
171 * Get the file journal entries for this file operation
173 * @param $oPredicates Array Pre-op info about files (format of FileOp::newPredicates)
174 * @param $nPredicates Array Post-op info about files (format of FileOp::newPredicates)
177 final public function getJournalEntries( array $oPredicates, array $nPredicates ) {
178 $nullEntries = array();
179 $updateEntries = array();
180 $deleteEntries = array();
181 $pathsUsed = array_merge( $this->storagePathsRead(), $this->storagePathsChanged() );
182 foreach ( $pathsUsed as $path ) {
183 $nullEntries[] = array( // assertion for recovery
186 'newSha1' => $this->fileSha1( $path, $oPredicates )
189 foreach ( $this->storagePathsChanged() as $path ) {
190 if ( $nPredicates['sha1'][$path] === false ) { // deleted
191 $deleteEntries[] = array(
196 } else { // created/updated
197 $updateEntries[] = array(
198 'op' => $this->fileExists( $path, $oPredicates ) ?
'update' : 'create',
200 'newSha1' => $nPredicates['sha1'][$path]
204 return array_merge( $nullEntries, $updateEntries, $deleteEntries );
208 * Check preconditions of the operation without writing anything
210 * @param $predicates Array
213 final public function precheck( array &$predicates ) {
214 if ( $this->state
!== self
::STATE_NEW
) {
215 return Status
::newFatal( 'fileop-fail-state', self
::STATE_NEW
, $this->state
);
217 $this->state
= self
::STATE_CHECKED
;
218 $status = $this->doPrecheck( $predicates );
219 if ( !$status->isOK() ) {
220 $this->failed
= true;
228 protected function doPrecheck( array &$predicates ) {
229 return Status
::newGood();
233 * Attempt the operation
237 final public function attempt() {
238 if ( $this->state
!== self
::STATE_CHECKED
) {
239 return Status
::newFatal( 'fileop-fail-state', self
::STATE_CHECKED
, $this->state
);
240 } elseif ( $this->failed
) { // failed precheck
241 return Status
::newFatal( 'fileop-fail-attempt-precheck' );
243 $this->state
= self
::STATE_ATTEMPTED
;
244 $status = $this->doAttempt();
245 if ( !$status->isOK() ) {
246 $this->failed
= true;
247 $this->logFailure( 'attempt' );
255 protected function doAttempt() {
256 return Status
::newGood();
260 * Attempt the operation in the background
264 final public function attemptAsync() {
266 $result = $this->attempt();
267 $this->async
= false;
272 * Get the file operation parameters
274 * @return Array (required params list, optional params list)
276 protected function allowedParams() {
277 return array( array(), array() );
281 * Adjust params to FileBackendStore internal file calls
283 * @param $params Array
284 * @return Array (required params list, optional params list)
286 protected function setFlags( array $params ) {
287 return array( 'async' => $this->async
) +
$params;
291 * Get a list of storage paths read from for this operation
295 final public function storagePathsRead() {
296 return array_map( 'FileBackend::normalizeStoragePath', $this->doStoragePathsRead() );
300 * @see FileOp::storagePathsRead()
303 protected function doStoragePathsRead() {
308 * Get a list of storage paths written to for this operation
312 final public function storagePathsChanged() {
313 return array_map( 'FileBackend::normalizeStoragePath', $this->doStoragePathsChanged() );
317 * @see FileOp::storagePathsChanged()
320 protected function doStoragePathsChanged() {
325 * Check for errors with regards to the destination file already existing.
326 * This also updates the destSameAsSource and sourceSha1 member variables.
327 * A bad status will be returned if there is no chance it can be overwritten.
329 * @param $predicates Array
332 protected function precheckDestExistence( array $predicates ) {
333 $status = Status
::newGood();
334 // Get hash of source file/string and the destination file
335 $this->sourceSha1
= $this->getSourceSha1Base36(); // FS file or data string
336 if ( $this->sourceSha1
=== null ) { // file in storage?
337 $this->sourceSha1
= $this->fileSha1( $this->params
['src'], $predicates );
339 $this->destSameAsSource
= false;
340 if ( $this->fileExists( $this->params
['dst'], $predicates ) ) {
341 if ( $this->getParam( 'overwrite' ) ) {
342 return $status; // OK
343 } elseif ( $this->getParam( 'overwriteSame' ) ) {
344 $dhash = $this->fileSha1( $this->params
['dst'], $predicates );
345 // Check if hashes are valid and match each other...
346 if ( !strlen( $this->sourceSha1
) ||
!strlen( $dhash ) ) {
347 $status->fatal( 'backend-fail-hashes' );
348 } elseif ( $this->sourceSha1
!== $dhash ) {
349 // Give an error if the files are not identical
350 $status->fatal( 'backend-fail-notsame', $this->params
['dst'] );
352 $this->destSameAsSource
= true; // OK
354 return $status; // do nothing; either OK or bad status
356 $status->fatal( 'backend-fail-alreadyexists', $this->params
['dst'] );
364 * precheckDestExistence() helper function to get the source file SHA-1.
365 * Subclasses should overwride this iff the source is not in storage.
367 * @return string|bool Returns false on failure
369 protected function getSourceSha1Base36() {
374 * Check if a file will exist in storage when this operation is attempted
376 * @param $source string Storage path
377 * @param $predicates Array
380 final protected function fileExists( $source, array $predicates ) {
381 if ( isset( $predicates['exists'][$source] ) ) {
382 return $predicates['exists'][$source]; // previous op assures this
384 $params = array( 'src' => $source, 'latest' => $this->useLatest
);
385 return $this->backend
->fileExists( $params );
390 * Get the SHA-1 of a file in storage when this operation is attempted
392 * @param $source string Storage path
393 * @param $predicates Array
394 * @return string|bool False on failure
396 final protected function fileSha1( $source, array $predicates ) {
397 if ( isset( $predicates['sha1'][$source] ) ) {
398 return $predicates['sha1'][$source]; // previous op assures this
400 $params = array( 'src' => $source, 'latest' => $this->useLatest
);
401 return $this->backend
->getFileSha1Base36( $params );
406 * Get the backend this operation is for
408 * @return FileBackendStore
410 public function getBackend() {
411 return $this->backend
;
415 * Log a file operation failure and preserve any temp files
417 * @param $action string
420 final public function logFailure( $action ) {
421 $params = $this->params
;
422 $params['failedAction'] = $action;
424 wfDebugLog( 'FileOperation', get_class( $this ) .
425 " failed (batch #{$this->batchId}): " . FormatJson
::encode( $params ) );
426 } catch ( Exception
$e ) {
427 // bad config? debug log error?
433 * Store a file into the backend from a file on the file system.
434 * Parameters for this operation are outlined in FileBackend::doOperations().
436 class StoreFileOp
extends FileOp
{
440 protected function allowedParams() {
441 return array( array( 'src', 'dst' ),
442 array( 'overwrite', 'overwriteSame', 'disposition' ) );
446 * @param $predicates array
449 protected function doPrecheck( array &$predicates ) {
450 $status = Status
::newGood();
451 // Check if the source file exists on the file system
452 if ( !is_file( $this->params
['src'] ) ) {
453 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
455 // Check if the source file is too big
456 } elseif ( filesize( $this->params
['src'] ) > $this->backend
->maxFileSizeInternal() ) {
457 $status->fatal( 'backend-fail-maxsize',
458 $this->params
['dst'], $this->backend
->maxFileSizeInternal() );
459 $status->fatal( 'backend-fail-store', $this->params
['src'], $this->params
['dst'] );
461 // Check if a file can be placed at the destination
462 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
463 $status->fatal( 'backend-fail-usable', $this->params
['dst'] );
464 $status->fatal( 'backend-fail-store', $this->params
['src'], $this->params
['dst'] );
467 // Check if destination file exists
468 $status->merge( $this->precheckDestExistence( $predicates ) );
469 if ( $status->isOK() ) {
470 // Update file existence predicates
471 $predicates['exists'][$this->params
['dst']] = true;
472 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
474 return $status; // safe to call attempt()
480 protected function doAttempt() {
481 // Store the file at the destination
482 if ( !$this->destSameAsSource
) {
483 return $this->backend
->storeInternal( $this->setFlags( $this->params
) );
485 return Status
::newGood();
489 * @return bool|string
491 protected function getSourceSha1Base36() {
492 wfSuppressWarnings();
493 $hash = sha1_file( $this->params
['src'] );
495 if ( $hash !== false ) {
496 $hash = wfBaseConvert( $hash, 16, 36, 31 );
501 protected function doStoragePathsChanged() {
502 return array( $this->params
['dst'] );
507 * Create a file in the backend with the given content.
508 * Parameters for this operation are outlined in FileBackend::doOperations().
510 class CreateFileOp
extends FileOp
{
511 protected function allowedParams() {
512 return array( array( 'content', 'dst' ),
513 array( 'overwrite', 'overwriteSame', 'disposition' ) );
516 protected function doPrecheck( array &$predicates ) {
517 $status = Status
::newGood();
518 // Check if the source data is too big
519 if ( strlen( $this->getParam( 'content' ) ) > $this->backend
->maxFileSizeInternal() ) {
520 $status->fatal( 'backend-fail-maxsize',
521 $this->params
['dst'], $this->backend
->maxFileSizeInternal() );
522 $status->fatal( 'backend-fail-create', $this->params
['dst'] );
524 // Check if a file can be placed at the destination
525 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
526 $status->fatal( 'backend-fail-usable', $this->params
['dst'] );
527 $status->fatal( 'backend-fail-create', $this->params
['dst'] );
530 // Check if destination file exists
531 $status->merge( $this->precheckDestExistence( $predicates ) );
532 if ( $status->isOK() ) {
533 // Update file existence predicates
534 $predicates['exists'][$this->params
['dst']] = true;
535 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
537 return $status; // safe to call attempt()
543 protected function doAttempt() {
544 if ( !$this->destSameAsSource
) {
545 // Create the file at the destination
546 return $this->backend
->createInternal( $this->setFlags( $this->params
) );
548 return Status
::newGood();
552 * @return bool|String
554 protected function getSourceSha1Base36() {
555 return wfBaseConvert( sha1( $this->params
['content'] ), 16, 36, 31 );
561 protected function doStoragePathsChanged() {
562 return array( $this->params
['dst'] );
567 * Copy a file from one storage path to another in the backend.
568 * Parameters for this operation are outlined in FileBackend::doOperations().
570 class CopyFileOp
extends FileOp
{
574 protected function allowedParams() {
575 return array( array( 'src', 'dst' ),
576 array( 'overwrite', 'overwriteSame', 'disposition' ) );
580 * @param $predicates array
583 protected function doPrecheck( array &$predicates ) {
584 $status = Status
::newGood();
585 // Check if the source file exists
586 if ( !$this->fileExists( $this->params
['src'], $predicates ) ) {
587 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
589 // Check if a file can be placed at the destination
590 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
591 $status->fatal( 'backend-fail-usable', $this->params
['dst'] );
592 $status->fatal( 'backend-fail-copy', $this->params
['src'], $this->params
['dst'] );
595 // Check if destination file exists
596 $status->merge( $this->precheckDestExistence( $predicates ) );
597 if ( $status->isOK() ) {
598 // Update file existence predicates
599 $predicates['exists'][$this->params
['dst']] = true;
600 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
602 return $status; // safe to call attempt()
608 protected function doAttempt() {
609 // Do nothing if the src/dst paths are the same
610 if ( $this->params
['src'] !== $this->params
['dst'] ) {
611 // Copy the file into the destination
612 if ( !$this->destSameAsSource
) {
613 return $this->backend
->copyInternal( $this->setFlags( $this->params
) );
616 return Status
::newGood();
622 protected function doStoragePathsRead() {
623 return array( $this->params
['src'] );
629 protected function doStoragePathsChanged() {
630 return array( $this->params
['dst'] );
635 * Move a file from one storage path to another in the backend.
636 * Parameters for this operation are outlined in FileBackend::doOperations().
638 class MoveFileOp
extends FileOp
{
642 protected function allowedParams() {
643 return array( array( 'src', 'dst' ),
644 array( 'overwrite', 'overwriteSame', 'disposition' ) );
648 * @param $predicates array
651 protected function doPrecheck( array &$predicates ) {
652 $status = Status
::newGood();
653 // Check if the source file exists
654 if ( !$this->fileExists( $this->params
['src'], $predicates ) ) {
655 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
657 // Check if a file can be placed at the destination
658 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
659 $status->fatal( 'backend-fail-usable', $this->params
['dst'] );
660 $status->fatal( 'backend-fail-move', $this->params
['src'], $this->params
['dst'] );
663 // Check if destination file exists
664 $status->merge( $this->precheckDestExistence( $predicates ) );
665 if ( $status->isOK() ) {
666 // Update file existence predicates
667 $predicates['exists'][$this->params
['src']] = false;
668 $predicates['sha1'][$this->params
['src']] = false;
669 $predicates['exists'][$this->params
['dst']] = true;
670 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
672 return $status; // safe to call attempt()
678 protected function doAttempt() {
679 // Do nothing if the src/dst paths are the same
680 if ( $this->params
['src'] !== $this->params
['dst'] ) {
681 if ( !$this->destSameAsSource
) {
682 // Move the file into the destination
683 return $this->backend
->moveInternal( $this->setFlags( $this->params
) );
685 // Just delete source as the destination needs no changes
686 $params = array( 'src' => $this->params
['src'] );
687 return $this->backend
->deleteInternal( $this->setFlags( $params ) );
690 return Status
::newGood();
696 protected function doStoragePathsRead() {
697 return array( $this->params
['src'] );
703 protected function doStoragePathsChanged() {
704 return array( $this->params
['src'], $this->params
['dst'] );
709 * Delete a file at the given storage path from the backend.
710 * Parameters for this operation are outlined in FileBackend::doOperations().
712 class DeleteFileOp
extends FileOp
{
716 protected function allowedParams() {
717 return array( array( 'src' ), array( 'ignoreMissingSource' ) );
720 protected $needsDelete = true;
723 * @param array $predicates
726 protected function doPrecheck( array &$predicates ) {
727 $status = Status
::newGood();
728 // Check if the source file exists
729 if ( !$this->fileExists( $this->params
['src'], $predicates ) ) {
730 if ( !$this->getParam( 'ignoreMissingSource' ) ) {
731 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
734 $this->needsDelete
= false;
736 // Update file existence predicates
737 $predicates['exists'][$this->params
['src']] = false;
738 $predicates['sha1'][$this->params
['src']] = false;
739 return $status; // safe to call attempt()
745 protected function doAttempt() {
746 if ( $this->needsDelete
) {
747 // Delete the source file
748 return $this->backend
->deleteInternal( $this->setFlags( $this->params
) );
750 return Status
::newGood();
756 protected function doStoragePathsChanged() {
757 return array( $this->params
['src'] );
762 * Placeholder operation that has no params and does nothing
764 class NullFileOp
extends FileOp
{}