summaryrefslogtreecommitdiff
path: root/includes/upload/UploadStash.php
blob: 7d80b4489eccf81f72da9b3cc851c2fc264c4017 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
<?php
/**
 * Temporary storage for uploaded files.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 * http://www.gnu.org/copyleft/gpl.html
 *
 * @file
 * @ingroup Upload
 */

/**
 * UploadStash is intended to accomplish a few things:
 *   - Enable applications to temporarily stash files without publishing them to
 *     the wiki.
 *      - Several parts of MediaWiki do this in similar ways: UploadBase,
 *        UploadWizard, and FirefoggChunkedExtension.
 *        And there are several that reimplement stashing from scratch, in
 *        idiosyncratic ways. The idea is to unify them all here.
 *        Mostly all of them are the same except for storing some custom fields,
 *        which we subsume into the data array.
 *   - Enable applications to find said files later, as long as the db table or
 *     temp files haven't been purged.
 *   - Enable the uploading user (and *ONLY* the uploading user) to access said
 *     files, and thumbnails of said files, via a URL. We accomplish this using
 *     a database table, with ownership checking as you might expect. See
 *     SpecialUploadStash, which implements a web interface to some files stored
 *     this way.
 *
 * UploadStash right now is *mostly* intended to show you one user's slice of
 * the entire stash. The user parameter is only optional because there are few
 * cases where we clean out the stash from an automated script. In the future we
 * might refactor this.
 *
 * UploadStash represents the entire stash of temporary files.
 * UploadStashFile is a filestore for the actual physical disk files.
 * UploadFromStash extends UploadBase, and represents a single stashed file as
 * it is moved from the stash to the regular file repository
 *
 * @ingroup Upload
 */
class UploadStash {
	// Format of the key for files -- has to be suitable as a filename itself (e.g. ab12cd34ef.jpg)
	const KEY_FORMAT_REGEX = '/^[\w-\.]+\.\w*$/';

	/**
	 * repository that this uses to store temp files
	 * public because we sometimes need to get a LocalFile within the same repo.
	 *
	 * @var LocalRepo
	 */
	public $repo;

	// array of initialized repo objects
	protected $files = array();

	// cache of the file metadata that's stored in the database
	protected $fileMetadata = array();

	// fileprops cache
	protected $fileProps = array();

	// current user
	protected $user, $userId, $isLoggedIn;

	/**
	 * Represents a temporary filestore, with metadata in the database.
	 * Designed to be compatible with the session stashing code in UploadBase
	 * (should replace it eventually).
	 *
	 * @param FileRepo $repo
	 * @param User $user (default null)
	 */
	public function __construct( FileRepo $repo, $user = null ) {
		// this might change based on wiki's configuration.
		$this->repo = $repo;

		// if a user was passed, use it. otherwise, attempt to use the global.
		// this keeps FileRepo from breaking when it creates an UploadStash object
		if ( $user ) {
			$this->user = $user;
		} else {
			global $wgUser;
			$this->user = $wgUser;
		}

		if ( is_object( $this->user ) ) {
			$this->userId = $this->user->getId();
			$this->isLoggedIn = $this->user->isLoggedIn();
		}
	}

	/**
	 * Get a file and its metadata from the stash.
	 * The noAuth param is a bit janky but is required for automated scripts
	 * which clean out the stash.
	 *
	 * @param string $key Key under which file information is stored
	 * @param bool $noAuth (optional) Don't check authentication. Used by maintenance scripts.
	 * @throws UploadStashFileNotFoundException
	 * @throws UploadStashNotLoggedInException
	 * @throws UploadStashWrongOwnerException
	 * @throws UploadStashBadPathException
	 * @return UploadStashFile
	 */
	public function getFile( $key, $noAuth = false ) {
		if ( !preg_match( self::KEY_FORMAT_REGEX, $key ) ) {
			throw new UploadStashBadPathException( "key '$key' is not in a proper format" );
		}

		if ( !$noAuth && !$this->isLoggedIn ) {
			throw new UploadStashNotLoggedInException( __METHOD__ .
				' No user is logged in, files must belong to users' );
		}

		if ( !isset( $this->fileMetadata[$key] ) ) {
			if ( !$this->fetchFileMetadata( $key ) ) {
				// If nothing was received, it's likely due to replication lag.
				// Check the master to see if the record is there.
				$this->fetchFileMetadata( $key, DB_MASTER );
			}

			if ( !isset( $this->fileMetadata[$key] ) ) {
				throw new UploadStashFileNotFoundException( "key '$key' not found in stash" );
			}

			// create $this->files[$key]
			$this->initFile( $key );

			// fetch fileprops
			if ( strlen( $this->fileMetadata[$key]['us_props'] ) ) {
				$this->fileProps[$key] = unserialize( $this->fileMetadata[$key]['us_props'] );
			} else { // b/c for rows with no us_props
				wfDebug( __METHOD__ . " fetched props for $key from file\n" );
				$path = $this->fileMetadata[$key]['us_path'];
				$this->fileProps[$key] = $this->repo->getFileProps( $path );
			}
		}

		if ( !$this->files[$key]->exists() ) {
			wfDebug( __METHOD__ . " tried to get file at $key, but it doesn't exist\n" );
			throw new UploadStashBadPathException( "path doesn't exist" );
		}

		if ( !$noAuth ) {
			if ( $this->fileMetadata[$key]['us_user'] != $this->userId ) {
				throw new UploadStashWrongOwnerException( "This file ($key) doesn't "
					. "belong to the current user." );
			}
		}

		return $this->files[$key];
	}

	/**
	 * Getter for file metadata.
	 *
	 * @param string $key Key under which file information is stored
	 * @return array
	 */
	public function getMetadata( $key ) {
		$this->getFile( $key );

		return $this->fileMetadata[$key];
	}

	/**
	 * Getter for fileProps
	 *
	 * @param string $key Key under which file information is stored
	 * @return array
	 */
	public function getFileProps( $key ) {
		$this->getFile( $key );

		return $this->fileProps[$key];
	}

	/**
	 * Stash a file in a temp directory and record that we did this in the
	 * database, along with other metadata.
	 *
	 * @param string $path Path to file you want stashed
	 * @param string $sourceType The type of upload that generated this file
	 *   (currently, I believe, 'file' or null)
	 * @throws UploadStashBadPathException
	 * @throws UploadStashFileException
	 * @throws UploadStashNotLoggedInException
	 * @return UploadStashFile|null File, or null on failure
	 */
	public function stashFile( $path, $sourceType = null ) {
		if ( !is_file( $path ) ) {
			wfDebug( __METHOD__ . " tried to stash file at '$path', but it doesn't exist\n" );
			throw new UploadStashBadPathException( "path doesn't exist" );
		}
		$fileProps = FSFile::getPropsFromPath( $path );
		wfDebug( __METHOD__ . " stashing file at '$path'\n" );

		// we will be initializing from some tmpnam files that don't have extensions.
		// most of MediaWiki assumes all uploaded files have good extensions. So, we fix this.
		$extension = self::getExtensionForPath( $path );
		if ( !preg_match( "/\\.\\Q$extension\\E$/", $path ) ) {
			$pathWithGoodExtension = "$path.$extension";
		} else {
			$pathWithGoodExtension = $path;
		}

		// If no key was supplied, make one.  a mysql insertid would be totally
		// reasonable here, except that for historical reasons, the key is this
		// random thing instead.  At least it's not guessable.
		//
		// Some things that when combined will make a suitably unique key.
		// see: http://www.jwz.org/doc/mid.html
		list( $usec, $sec ) = explode( ' ', microtime() );
		$usec = substr( $usec, 2 );
		$key = wfBaseConvert( $sec . $usec, 10, 36 ) . '.' .
			wfBaseConvert( mt_rand(), 10, 36 ) . '.' .
			$this->userId . '.' .
			$extension;

		$this->fileProps[$key] = $fileProps;

		if ( !preg_match( self::KEY_FORMAT_REGEX, $key ) ) {
			throw new UploadStashBadPathException( "key '$key' is not in a proper format" );
		}

		wfDebug( __METHOD__ . " key for '$path': $key\n" );

		// if not already in a temporary area, put it there
		$storeStatus = $this->repo->storeTemp( basename( $pathWithGoodExtension ), $path );

		if ( !$storeStatus->isOK() ) {
			// It is a convention in MediaWiki to only return one error per API
			// exception, even if multiple errors are available. We use reset()
			// to pick the "first" thing that was wrong, preferring errors to
			// warnings. This is a bit lame, as we may have more info in the
			// $storeStatus and we're throwing it away, but to fix it means
			// redesigning API errors significantly.
			// $storeStatus->value just contains the virtual URL (if anything)
			// which is probably useless to the caller.
			$error = $storeStatus->getErrorsArray();
			$error = reset( $error );
			if ( !count( $error ) ) {
				$error = $storeStatus->getWarningsArray();
				$error = reset( $error );
				if ( !count( $error ) ) {
					$error = array( 'unknown', 'no error recorded' );
				}
			}
			// At this point, $error should contain the single "most important"
			// error, plus any parameters.
			$errorMsg = array_shift( $error );
			throw new UploadStashFileException( "Error storing file in '$path': "
				. wfMessage( $errorMsg, $error )->text() );
		}
		$stashPath = $storeStatus->value;

		// fetch the current user ID
		if ( !$this->isLoggedIn ) {
			throw new UploadStashNotLoggedInException( __METHOD__
				. ' No user is logged in, files must belong to users' );
		}

		// insert the file metadata into the db.
		wfDebug( __METHOD__ . " inserting $stashPath under $key\n" );
		$dbw = $this->repo->getMasterDb();

		$this->fileMetadata[$key] = array(
			'us_id' => $dbw->nextSequenceValue( 'uploadstash_us_id_seq' ),
			'us_user' => $this->userId,
			'us_key' => $key,
			'us_orig_path' => $path,
			'us_path' => $stashPath, // virtual URL
			'us_props' => $dbw->encodeBlob( serialize( $fileProps ) ),
			'us_size' => $fileProps['size'],
			'us_sha1' => $fileProps['sha1'],
			'us_mime' => $fileProps['mime'],
			'us_media_type' => $fileProps['media_type'],
			'us_image_width' => $fileProps['width'],
			'us_image_height' => $fileProps['height'],
			'us_image_bits' => $fileProps['bits'],
			'us_source_type' => $sourceType,
			'us_timestamp' => $dbw->timestamp(),
			'us_status' => 'finished'
		);

		$dbw->insert(
			'uploadstash',
			$this->fileMetadata[$key],
			__METHOD__
		);

		// store the insertid in the class variable so immediate retrieval
		// (possibly laggy) isn't necesary.
		$this->fileMetadata[$key]['us_id'] = $dbw->insertId();

		# create the UploadStashFile object for this file.
		$this->initFile( $key );

		return $this->getFile( $key );
	}

	/**
	 * Remove all files from the stash.
	 * Does not clean up files in the repo, just the record of them.
	 *
	 * @throws UploadStashNotLoggedInException
	 * @return bool Success
	 */
	public function clear() {
		if ( !$this->isLoggedIn ) {
			throw new UploadStashNotLoggedInException( __METHOD__
				. ' No user is logged in, files must belong to users' );
		}

		wfDebug( __METHOD__ . ' clearing all rows for user ' . $this->userId . "\n" );
		$dbw = $this->repo->getMasterDb();
		$dbw->delete(
			'uploadstash',
			array( 'us_user' => $this->userId ),
			__METHOD__
		);

		# destroy objects.
		$this->files = array();
		$this->fileMetadata = array();

		return true;
	}

	/**
	 * Remove a particular file from the stash.  Also removes it from the repo.
	 *
	 * @param string $key
	 * @throws UploadStashNoSuchKeyException|UploadStashNotLoggedInException
	 * @throws UploadStashWrongOwnerException
	 * @return bool Success
	 */
	public function removeFile( $key ) {
		if ( !$this->isLoggedIn ) {
			throw new UploadStashNotLoggedInException( __METHOD__
				. ' No user is logged in, files must belong to users' );
		}

		$dbw = $this->repo->getMasterDb();

		// this is a cheap query. it runs on the master so that this function
		// still works when there's lag. It won't be called all that often.
		$row = $dbw->selectRow(
			'uploadstash',
			'us_user',
			array( 'us_key' => $key ),
			__METHOD__
		);

		if ( !$row ) {
			throw new UploadStashNoSuchKeyException( "No such key ($key), cannot remove" );
		}

		if ( $row->us_user != $this->userId ) {
			throw new UploadStashWrongOwnerException( "Can't delete: "
				. "the file ($key) doesn't belong to this user." );
		}

		return $this->removeFileNoAuth( $key );
	}

	/**
	 * Remove a file (see removeFile), but doesn't check ownership first.
	 *
	 * @param string $key
	 * @return bool Success
	 */
	public function removeFileNoAuth( $key ) {
		wfDebug( __METHOD__ . " clearing row $key\n" );

		// Ensure we have the UploadStashFile loaded for this key
		$this->getFile( $key, true );

		$dbw = $this->repo->getMasterDb();

		$dbw->delete(
			'uploadstash',
			array( 'us_key' => $key ),
			__METHOD__
		);

		/** @todo Look into UnregisteredLocalFile and find out why the rv here is
		 *  sometimes wrong (false when file was removed). For now, ignore.
		 */
		$this->files[$key]->remove();

		unset( $this->files[$key] );
		unset( $this->fileMetadata[$key] );

		return true;
	}

	/**
	 * List all files in the stash.
	 *
	 * @throws UploadStashNotLoggedInException
	 * @return array
	 */
	public function listFiles() {
		if ( !$this->isLoggedIn ) {
			throw new UploadStashNotLoggedInException( __METHOD__
				. ' No user is logged in, files must belong to users' );
		}

		$dbr = $this->repo->getSlaveDb();
		$res = $dbr->select(
			'uploadstash',
			'us_key',
			array( 'us_user' => $this->userId ),
			__METHOD__
		);

		if ( !is_object( $res ) || $res->numRows() == 0 ) {
			// nothing to do.
			return false;
		}

		// finish the read before starting writes.
		$keys = array();
		foreach ( $res as $row ) {
			array_push( $keys, $row->us_key );
		}

		return $keys;
	}

	/**
	 * Find or guess extension -- ensuring that our extension matches our MIME type.
	 * Since these files are constructed from php tempnames they may not start off
	 * with an extension.
	 * XXX this is somewhat redundant with the checks that ApiUpload.php does with incoming
	 * uploads versus the desired filename. Maybe we can get that passed to us...
	 * @param string $path
	 * @throws UploadStashFileException
	 * @return string
	 */
	public static function getExtensionForPath( $path ) {
		global $wgFileBlacklist;
		// Does this have an extension?
		$n = strrpos( $path, '.' );
		$extension = null;
		if ( $n !== false ) {
			$extension = $n ? substr( $path, $n + 1 ) : '';
		} else {
			// If not, assume that it should be related to the MIME type of the original file.
			$magic = MimeMagic::singleton();
			$mimeType = $magic->guessMimeType( $path );
			$extensions = explode( ' ', MimeMagic::singleton()->getExtensionsForType( $mimeType ) );
			if ( count( $extensions ) ) {
				$extension = $extensions[0];
			}
		}

		if ( is_null( $extension ) ) {
			throw new UploadStashFileException( "extension is null" );
		}

		$extension = File::normalizeExtension( $extension );
		if ( in_array( $extension, $wgFileBlacklist ) ) {
			// The file should already be checked for being evil.
			// However, if somehow we got here, we definitely
			// don't want to give it an extension of .php and
			// put it in a web accesible directory.
			return '';
		}

		return $extension;
	}

	/**
	 * Helper function: do the actual database query to fetch file metadata.
	 *
	 * @param string $key
	 * @param int $readFromDB Constant (default: DB_SLAVE)
	 * @return bool
	 */
	protected function fetchFileMetadata( $key, $readFromDB = DB_SLAVE ) {
		// populate $fileMetadata[$key]
		$dbr = null;
		if ( $readFromDB === DB_MASTER ) {
			// sometimes reading from the master is necessary, if there's replication lag.
			$dbr = $this->repo->getMasterDb();
		} else {
			$dbr = $this->repo->getSlaveDb();
		}

		$row = $dbr->selectRow(
			'uploadstash',
			'*',
			array( 'us_key' => $key ),
			__METHOD__
		);

		if ( !is_object( $row ) ) {
			// key wasn't present in the database. this will happen sometimes.
			return false;
		}

		$this->fileMetadata[$key] = (array)$row;
		$this->fileMetadata[$key]['us_props'] = $dbr->decodeBlob( $row->us_props );

		return true;
	}

	/**
	 * Helper function: Initialize the UploadStashFile for a given file.
	 *
	 * @param string $key Key under which to store the object
	 * @throws UploadStashZeroLengthFileException
	 * @return bool
	 */
	protected function initFile( $key ) {
		$file = new UploadStashFile( $this->repo, $this->fileMetadata[$key]['us_path'], $key );
		if ( $file->getSize() === 0 ) {
			throw new UploadStashZeroLengthFileException( "File is zero length" );
		}
		$this->files[$key] = $file;

		return true;
	}
}

class UploadStashFile extends UnregisteredLocalFile {
	private $fileKey;
	private $urlName;
	protected $url;

	/**
	 * A LocalFile wrapper around a file that has been temporarily stashed,
	 * so we can do things like create thumbnails for it. Arguably
	 * UnregisteredLocalFile should be handling its own file repo but that
	 * class is a bit retarded currently.
	 *
	 * @param FileRepo $repo Repository where we should find the path
	 * @param string $path Path to file
	 * @param string $key Key to store the path and any stashed data under
	 * @throws UploadStashBadPathException
	 * @throws UploadStashFileNotFoundException
	 */
	public function __construct( $repo, $path, $key ) {
		$this->fileKey = $key;

		// resolve mwrepo:// urls
		if ( $repo->isVirtualUrl( $path ) ) {
			$path = $repo->resolveVirtualUrl( $path );
		} else {
			// check if path appears to be sane, no parent traversals,
			// and is in this repo's temp zone.
			$repoTempPath = $repo->getZonePath( 'temp' );
			if ( ( !$repo->validateFilename( $path ) ) ||
				( strpos( $path, $repoTempPath ) !== 0 )
			) {
				wfDebug( "UploadStash: tried to construct an UploadStashFile "
					. "from a file that should already exist at '$path', but path is not valid\n" );
				throw new UploadStashBadPathException( 'path is not valid' );
			}

			// check if path exists! and is a plain file.
			if ( !$repo->fileExists( $path ) ) {
				wfDebug( "UploadStash: tried to construct an UploadStashFile from "
					. "a file that should already exist at '$path', but path is not found\n" );
				throw new UploadStashFileNotFoundException( 'cannot find path, or not a plain file' );
			}
		}

		parent::__construct( false, $repo, $path, false );

		$this->name = basename( $this->path );
	}

	/**
	 * A method needed by the file transforming and scaling routines in File.php
	 * We do not necessarily care about doing the description at this point
	 * However, we also can't return the empty string, as the rest of MediaWiki
	 * demands this (and calls to imagemagick convert require it to be there)
	 *
	 * @return string Dummy value
	 */
	public function getDescriptionUrl() {
		return $this->getUrl();
	}

	/**
	 * Get the path for the thumbnail (actually any transformation of this file)
	 * The actual argument is the result of thumbName although we seem to have
	 * buggy code elsewhere that expects a boolean 'suffix'
	 *
	 * @param string $thumbName Name of thumbnail (e.g. "120px-123456.jpg" ),
	 *   or false to just get the path
	 * @return string Path thumbnail should take on filesystem, or containing
	 *   directory if thumbname is false
	 */
	public function getThumbPath( $thumbName = false ) {
		$path = dirname( $this->path );
		if ( $thumbName !== false ) {
			$path .= "/$thumbName";
		}

		return $path;
	}

	/**
	 * Return the file/url base name of a thumbnail with the specified parameters.
	 * We override this because we want to use the pretty url name instead of the
	 * ugly file name.
	 *
	 * @param array $params Handler-specific parameters
	 * @param int $flags Bitfield that supports THUMB_* constants
	 * @return string Base name for URL, like '120px-12345.jpg', or null if there is no handler
	 */
	function thumbName( $params, $flags = 0 ) {
		return $this->generateThumbName( $this->getUrlName(), $params );
	}

	/**
	 * Helper function -- given a 'subpage', return the local URL,
	 * e.g. /wiki/Special:UploadStash/subpage
	 * @param string $subPage
	 * @return string Local URL for this subpage in the Special:UploadStash space.
	 */
	private function getSpecialUrl( $subPage ) {
		return SpecialPage::getTitleFor( 'UploadStash', $subPage )->getLocalURL();
	}

	/**
	 * Get a URL to access the thumbnail
	 * This is required because the model of how files work requires that
	 * the thumbnail urls be predictable. However, in our model the URL is
	 * not based on the filename (that's hidden in the db)
	 *
	 * @param string $thumbName Basename of thumbnail file -- however, we don't
	 *   want to use the file exactly
	 * @return string URL to access thumbnail, or URL with partial path
	 */
	public function getThumbUrl( $thumbName = false ) {
		wfDebug( __METHOD__ . " getting for $thumbName \n" );

		return $this->getSpecialUrl( 'thumb/' . $this->getUrlName() . '/' . $thumbName );
	}

	/**
	 * The basename for the URL, which we want to not be related to the filename.
	 * Will also be used as the lookup key for a thumbnail file.
	 *
	 * @return string Base url name, like '120px-123456.jpg'
	 */
	public function getUrlName() {
		if ( !$this->urlName ) {
			$this->urlName = $this->fileKey;
		}

		return $this->urlName;
	}

	/**
	 * Return the URL of the file, if for some reason we wanted to download it
	 * We tend not to do this for the original file, but we do want thumb icons
	 *
	 * @return string Url
	 */
	public function getUrl() {
		if ( !isset( $this->url ) ) {
			$this->url = $this->getSpecialUrl( 'file/' . $this->getUrlName() );
		}

		return $this->url;
	}

	/**
	 * Parent classes use this method, for no obvious reason, to return the path
	 * (relative to wiki root, I assume). But with this class, the URL is
	 * unrelated to the path.
	 *
	 * @return string Url
	 */
	public function getFullUrl() {
		return $this->getUrl();
	}

	/**
	 * Getter for file key (the unique id by which this file's location &
	 * metadata is stored in the db)
	 *
	 * @return string File key
	 */
	public function getFileKey() {
		return $this->fileKey;
	}

	/**
	 * Remove the associated temporary file
	 * @return status Success
	 */
	public function remove() {
		if ( !$this->repo->fileExists( $this->path ) ) {
			// Maybe the file's already been removed? This could totally happen in UploadBase.
			return true;
		}

		return $this->repo->freeTemp( $this->path );
	}

	public function exists() {
		return $this->repo->fileExists( $this->path );
	}
}

class UploadStashException extends MWException {
}

class UploadStashNotAvailableException extends UploadStashException {
}

class UploadStashFileNotFoundException extends UploadStashException {
}

class UploadStashBadPathException extends UploadStashException {
}

class UploadStashFileException extends UploadStashException {
}

class UploadStashZeroLengthFileException extends UploadStashException {
}

class UploadStashNotLoggedInException extends UploadStashException {
}

class UploadStashWrongOwnerException extends UploadStashException {
}

class UploadStashNoSuchKeyException extends UploadStashException {
}