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
$e ) {
427 // bad config? debug log error?
433 * Store a file into the backend from a file on the file system.
434 * Parameters similar to FileBackendStore::storeInternal(), which include:
435 * src : source path on file system
436 * dst : destination storage path
437 * overwrite : do nothing and pass if an identical file exists at destination
438 * overwriteSame : override any existing file at destination
440 class StoreFileOp
extends FileOp
{
441 protected function allowedParams() {
442 return array( array( 'src', 'dst' ), array( 'overwrite', 'overwriteSame' ) );
445 protected function doPrecheck( array &$predicates ) {
446 $status = Status
::newGood();
447 // Check if the source file exists on the file system
448 if ( !is_file( $this->params
['src'] ) ) {
449 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
451 // Check if the source file is too big
452 } elseif ( filesize( $this->params
['src'] ) > $this->backend
->maxFileSizeInternal() ) {
453 $status->fatal( 'backend-fail-store', $this->params
['src'], $this->params
['dst'] );
455 // Check if a file can be placed at the destination
456 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
457 $status->fatal( 'backend-fail-store', $this->params
['src'], $this->params
['dst'] );
460 // Check if destination file exists
461 $status->merge( $this->precheckDestExistence( $predicates ) );
462 if ( $status->isOK() ) {
463 // Update file existence predicates
464 $predicates['exists'][$this->params
['dst']] = true;
465 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
467 return $status; // safe to call attempt()
470 protected function doAttempt() {
471 // Store the file at the destination
472 if ( !$this->destSameAsSource
) {
473 return $this->backend
->storeInternal( $this->setFlags( $this->params
) );
475 return Status
::newGood();
478 protected function getSourceSha1Base36() {
479 wfSuppressWarnings();
480 $hash = sha1_file( $this->params
['src'] );
482 if ( $hash !== false ) {
483 $hash = wfBaseConvert( $hash, 16, 36, 31 );
488 protected function doStoragePathsChanged() {
489 return array( $this->params
['dst'] );
494 * Create a file in the backend with the given content.
495 * Parameters similar to FileBackendStore::createInternal(), which include:
496 * content : the raw file contents
497 * dst : destination storage path
498 * overwrite : do nothing and pass if an identical file exists at destination
499 * overwriteSame : override any existing file at destination
501 class CreateFileOp
extends FileOp
{
502 protected function allowedParams() {
503 return array( array( 'content', 'dst' ), array( 'overwrite', 'overwriteSame' ) );
506 protected function doPrecheck( array &$predicates ) {
507 $status = Status
::newGood();
508 // Check if the source data is too big
509 if ( strlen( $this->getParam( 'content' ) ) > $this->backend
->maxFileSizeInternal() ) {
510 $status->fatal( 'backend-fail-create', $this->params
['dst'] );
512 // Check if a file can be placed at the destination
513 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
514 $status->fatal( 'backend-fail-create', $this->params
['dst'] );
517 // Check if destination file exists
518 $status->merge( $this->precheckDestExistence( $predicates ) );
519 if ( $status->isOK() ) {
520 // Update file existence predicates
521 $predicates['exists'][$this->params
['dst']] = true;
522 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
524 return $status; // safe to call attempt()
527 protected function doAttempt() {
528 if ( !$this->destSameAsSource
) {
529 // Create the file at the destination
530 return $this->backend
->createInternal( $this->setFlags( $this->params
) );
532 return Status
::newGood();
535 protected function getSourceSha1Base36() {
536 return wfBaseConvert( sha1( $this->params
['content'] ), 16, 36, 31 );
539 protected function doStoragePathsChanged() {
540 return array( $this->params
['dst'] );
545 * Copy a file from one storage path to another in the backend.
546 * Parameters similar to FileBackendStore::copyInternal(), which include:
547 * src : source storage path
548 * dst : destination storage path
549 * overwrite : do nothing and pass if an identical file exists at destination
550 * overwriteSame : override any existing file at destination
552 class CopyFileOp
extends FileOp
{
553 protected function allowedParams() {
554 return array( array( 'src', 'dst' ), array( 'overwrite', 'overwriteSame' ) );
557 protected function doPrecheck( array &$predicates ) {
558 $status = Status
::newGood();
559 // Check if the source file exists
560 if ( !$this->fileExists( $this->params
['src'], $predicates ) ) {
561 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
563 // Check if a file can be placed at the destination
564 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
565 $status->fatal( 'backend-fail-copy', $this->params
['src'], $this->params
['dst'] );
568 // Check if destination file exists
569 $status->merge( $this->precheckDestExistence( $predicates ) );
570 if ( $status->isOK() ) {
571 // Update file existence predicates
572 $predicates['exists'][$this->params
['dst']] = true;
573 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
575 return $status; // safe to call attempt()
578 protected function doAttempt() {
579 // Do nothing if the src/dst paths are the same
580 if ( $this->params
['src'] !== $this->params
['dst'] ) {
581 // Copy the file into the destination
582 if ( !$this->destSameAsSource
) {
583 return $this->backend
->copyInternal( $this->setFlags( $this->params
) );
586 return Status
::newGood();
589 protected function doStoragePathsRead() {
590 return array( $this->params
['src'] );
593 protected function doStoragePathsChanged() {
594 return array( $this->params
['dst'] );
599 * Move a file from one storage path to another in the backend.
600 * Parameters similar to FileBackendStore::moveInternal(), which include:
601 * src : source storage path
602 * dst : destination storage path
603 * overwrite : do nothing and pass if an identical file exists at destination
604 * overwriteSame : override any existing file at destination
606 class MoveFileOp
extends FileOp
{
607 protected function allowedParams() {
608 return array( array( 'src', 'dst' ), array( 'overwrite', 'overwriteSame' ) );
611 protected function doPrecheck( array &$predicates ) {
612 $status = Status
::newGood();
613 // Check if the source file exists
614 if ( !$this->fileExists( $this->params
['src'], $predicates ) ) {
615 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
617 // Check if a file can be placed at the destination
618 } elseif ( !$this->backend
->isPathUsableInternal( $this->params
['dst'] ) ) {
619 $status->fatal( 'backend-fail-move', $this->params
['src'], $this->params
['dst'] );
622 // Check if destination file exists
623 $status->merge( $this->precheckDestExistence( $predicates ) );
624 if ( $status->isOK() ) {
625 // Update file existence predicates
626 $predicates['exists'][$this->params
['src']] = false;
627 $predicates['sha1'][$this->params
['src']] = false;
628 $predicates['exists'][$this->params
['dst']] = true;
629 $predicates['sha1'][$this->params
['dst']] = $this->sourceSha1
;
631 return $status; // safe to call attempt()
634 protected function doAttempt() {
635 // Do nothing if the src/dst paths are the same
636 if ( $this->params
['src'] !== $this->params
['dst'] ) {
637 if ( !$this->destSameAsSource
) {
638 // Move the file into the destination
639 return $this->backend
->moveInternal( $this->setFlags( $this->params
) );
641 // Just delete source as the destination needs no changes
642 $params = array( 'src' => $this->params
['src'] );
643 return $this->backend
->deleteInternal( $this->setFlags( $params ) );
646 return Status
::newGood();
649 protected function doStoragePathsRead() {
650 return array( $this->params
['src'] );
653 protected function doStoragePathsChanged() {
654 return array( $this->params
['src'], $this->params
['dst'] );
659 * Delete a file at the given storage path from the backend.
660 * Parameters similar to FileBackendStore::deleteInternal(), which include:
661 * src : source storage path
662 * ignoreMissingSource : don't return an error if the file does not exist
664 class DeleteFileOp
extends FileOp
{
665 protected function allowedParams() {
666 return array( array( 'src' ), array( 'ignoreMissingSource' ) );
669 protected $needsDelete = true;
671 protected function doPrecheck( array &$predicates ) {
672 $status = Status
::newGood();
673 // Check if the source file exists
674 if ( !$this->fileExists( $this->params
['src'], $predicates ) ) {
675 if ( !$this->getParam( 'ignoreMissingSource' ) ) {
676 $status->fatal( 'backend-fail-notexists', $this->params
['src'] );
679 $this->needsDelete
= false;
681 // Update file existence predicates
682 $predicates['exists'][$this->params
['src']] = false;
683 $predicates['sha1'][$this->params
['src']] = false;
684 return $status; // safe to call attempt()
687 protected function doAttempt() {
688 if ( $this->needsDelete
) {
689 // Delete the source file
690 return $this->backend
->deleteInternal( $this->setFlags( $this->params
) );
692 return Status
::newGood();
695 protected function doStoragePathsChanged() {
696 return array( $this->params
['src'] );
701 * Placeholder operation that has no params and does nothing
703 class NullFileOp
extends FileOp
{}