-
-
Notifications
You must be signed in to change notification settings - Fork 338
/
Entry.dox
617 lines (436 loc) · 17 KB
/
Entry.dox
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
/*
* Copyright 2011 Haiku, Inc. All rights reserved.
* Distributed under the terms of the MIT License.
*
* Authors:
* Tyler Dauwalder
* Simon Cusack, scusack@users.sf.net
* John Scipione, jscipione@gmail.com
* Corresponds to:
* headers/os/storage/Entry.h hrev43528
* src/kits/storage/Entry.cpp hrev43528
*/
/*!
\file Entry.h
\brief Provides the BEntry class and entry_ref implementations.
*/
/*!
\struct entry_ref
\brief A filesystem entry represented as a name in a concrete directory.
entry_refs may refer to pre-existing (concrete) files, as well as
non-existing (abstract) files. However, the parent directory of the file
\b must exist.
The result of this dichotomy is a blending of the persistence gained by
referring to entries with a reference to their internal filesystem node and
the flexibility gained by referring to entries by name.
For example, if the directory in which the entry resides (or a directory
further up in the hierarchy) is moved or renamed, the entry_ref will still
refer to the correct file (whereas a pathname to the previous location of
the file would now be invalid).
On the other hand, say that the entry_ref refers to a concrete file. If the
file itself is renamed, the entry_ref now refers to an abstract file with
the old name (the upside in this case is that abstract entries may be
represented by entry_refs without preallocating an internal filesystem node
for them).
*/
/*!
\fn entry_ref::entry_ref()
\brief Creates an uninitialized entry_ref object.
*/
/*!
\fn entry_ref::entry_ref(dev_t dev, ino_t dir, const char* name)
\brief Creates an entry_ref object initialized to the given file name in
the given directory on the given device.
\a name may refer to either a pre-existing file in the given directory, or
a non-existent file. No explicit checking is done to verify validity of the
given arguments, but later use of the entry_ref will fail if \p dev is not
a valid device or \a dir is a not a directory on \p dev.
\param dev the device on which the entry's parent directory resides
\param dir the directory in which the entry resides
\param name the leaf name of the entry, which is not required to exist
*/
/*!
\fn entry_ref::entry_ref(const entry_ref& ref)
\brief Returns a copy of the passed in entry_ref object.
\param ref A reference to an entry_ref to copy.
*/
/*!
\fn entry_ref::~entry_ref()
\brief Destroys the object and frees the storage allocated for the leaf
name, if necessary.
*/
/*!
\fn status_t entry_ref::set_name(const char* name)
\brief Set the entry_ref's leaf name, freeing the storage allocated for any
previous name and then making a copy of the new name.
\param name Pointer to a null-terminated string containing the new name for
the entry. May be \c NULL.
*/
/*!
\fn bool entry_ref::operator==(const entry_ref& ref) const
\brief Compares the entry_ref object with the passed in entry_ref,
returning \c true if they are equal.
\returns \c true if he entry_refs are equal, \c false otherwise.
*/
/*!
\fn bool entry_ref::operator!=(const entry_ref& ref) const
\brief Compares the entry_ref object with the passed in entry_ref,
returning \c true if they are NOT equal.
\returns \c true if the entry_refs are NOT equal, \c false otherwise.
*/
/*!
\fn entry_ref& entry_ref::operator=(const entry_ref& ref)
\brief Makes the entry_ref object a copy of the passed in entry_ref.
\param ref The entry_ref to copy.
\returns A pointer to the resulting entry_ref copy.
*/
/*!
\var dev_t entry_ref::device
\brief The device id of the storage device on which the entry resides
*/
/*!
\var ino_t entry_ref::directory
\brief The inode number of the directory in which the entry resides
*/
/*!
\var char *entry_ref::name
\brief The leaf name of the entry
*/
/*!
\class BEntry
\ingroup storage
\ingroup libbe
\brief A location in the filesystem.
The BEntry class defines objects that represent "locations" in the file
system hierarchy. Each location (or entry) is given as a name within a
directory. For example, if you create a BEntry like this:
\code
BEntry entry("/boot/home/fido");
\endcode
the resulting BEntry object represents the location of the file \c fido
within the <tt>/boot/home</tt> directory.
*/
/*!
\fn BEntry::BEntry()
\brief Creates an uninitialized BEntry object.
Should be followed by a call to one of the SetTo() methods, or an
assignment.
- SetTo(const BDirectory*, const char*, bool)
- SetTo(const entry_ref*, bool)
- SetTo(const char*, bool)
- operator=(const BEntry&)
*/
/*!
\fn BEntry::BEntry(const BDirectory* dir, const char* path, bool traverse)
\brief Creates a BEntry initialized to the given directory and path
combination.
If traverse is \c true and \a path refers to a symlink, the BEntry will
refer to the linked file; if \c false, the BEntry will refer to the
symlink itself.
\param dir The base directory in which the \a path resides.
\param path Relative path based off of \a dir.
\param traverse Whether or not to traverse symbolic links.
\see BEntry::SetTo(const BDirectory*, const char *, bool)
*/
/*!
\fn BEntry::BEntry(const entry_ref* ref, bool traverse)
\brief Creates a BEntry for the file referred to by the passed in
entry_ref.
If traverse is \c true and \a ref refers to a symlink, the BEntry
will refer to the linked file; if \c false, the BEntry will refer
to the symlink itself.
\param ref The entry_ref referring to the given file.
\param traverse Whether or not symlinks are to be traversed.
\sa BEntry::SetTo(const entry_ref*, bool)
*/
/*!
\fn BEntry::BEntry(const char* path, bool traverse)
\brief Creates a BEntry initialized to the given path.
If \a path is relative, it will be reckoned off the current working
directory. If \a path refers to a symlink and traverse is \c true, the
BEntry will refer to the linked file. If traverse is \c false, the
BEntry will refer to the symlink itself.
\param path The path of the file.
\param traverse Whether or not symlinks are to be traversed.
\sa BEntry::SetTo(const char*, bool)
*/
/*!
\fn BEntry::BEntry(const BEntry& entry)
\brief Creates a copy of the given BEntry.
\param entry the entry to be copied
\sa operator=(const BEntry&)
*/
/*!
\fn BEntry::~BEntry()
\brief Frees all of the allocated resources of the BEntry.
\sa Unset()
*/
/*!
\fn status_t BEntry::InitCheck() const
\brief Returns the result of the most recent construction or SetTo() call.
\returns A status code.
\retval B_OK Success
\retval B_NO_INIT The object has been Unset() or is uninitialized.
*/
/*!
\fn bool BEntry::Exists() const
\brief Returns whether or not the entry exists in the filesystem.
\returns \c true if the entry exists, \c false if the entry does not exist.
*/
/*!
\fn status_t BEntry::GetStat(struct stat *result) const
\brief Fills in a stat structure for the entry.
The information is copied into the \c stat structure pointed to
by \a result.
\note The BStatable object does not cache the stat structure -- each time
you call GetStat() fresh stat information is retrieved.
\param result A pointer to a pre-allocated structure into which the stat
information is copied.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn status_t BEntry::SetTo(const BDirectory* dir, const char* path,
bool traverse)
\brief Reinitializes the BEntry to the path or directory path combination,
resolving symlinks if traverse is \c true.
\param dir The base directory in which the \a path resides.
\param path Relative path based off of \a dir.
\param traverse Whether or not to traverse symbolic links.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn status_t BEntry::SetTo(const entry_ref* ref, bool traverse)
\brief Reinitializes the BEntry to the passed in entry_ref object
resolving symlinks if traverse is \c true.
\param ref The entry_ref referring to the given file.
\param traverse Whether or not symlinks are to be traversed.
\returns \c B_OK on success, or an error code on failure.
\sa BEntry::BEntry(const entry_ref* ref, bool traverse)
*/
/*!
\fn status_t BEntry::SetTo(const char* path, bool traverse)
\brief Reinitializes the BEntry object to the path, resolving symlinks if
traverse is \c true.
\param path The path of the file.
\param traverse Whether or not symlinks are to be traversed.
\returns \c B_OK on success, or an error code on failure.
\sa BEntry::BEntry(const char* path, bool traverse)
*/
/*!
void BEntry::Unset()
\brief Reinitializes the BEntry to an uninitialized BEntry object
*/
/*!
\fn status_t BEntry::GetRef(entry_ref* ref) const
\brief Gets an entry_ref structure for the BEntry.
\param ref A pointer to a preallocated entry_ref object into which the
result is copied.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn status_t BEntry::GetPath(BPath* path) const
\brief Gets the path for the BEntry.
\param path A pointer to a pre-allocated BPath object into which the
result is copied.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn status_t BEntry::GetParent(BEntry* entry) const
\brief Gets the parent of the BEntry as a BEntry.
If the function fails, the argument is Unset(). Destructive calls to
GetParent() are allowed, i.e.:
\code
BEntry entry("/boot/home/fido");
status_t err;
char name[B_FILE_NAME_LENGTH];
// Spit out the path components backwards, one at a time.
do {
entry.GetName(name);
printf("> %s\n", name);
} while ((err=entry.GetParent(&entry)) == B_OK);
// Complain for reasons other than reaching the top.
if (err != B_ENTRY_NOT_FOUND)
printf(">> Error: %s\n", strerror(err));
\endcode
will output:
\code
> fido
> home
> boot
> .
\endcode
\param entry A pointer to a pre-allocated BEntry object into which the
result is stored.
\returns A status code.
\retval B_OK Success
\retval B_ENTRY_NOT_FOUND Attempted to get the parent of the root
directory.
*/
/*!
\fn status_t BEntry::GetParent(BDirectory* dir) const
\brief Gets the parent of the BEntry as a BDirectory.
If the function fails, the argument is Unset().
\param dir A pointer to a pre-allocated BDirectory object into which the
result is copied.
\returns A status code.
\retval B_OK Success
\retval B_ENTRY_NOT_FOUND Attempted to get the parent of the root
directory.
*/
/*!
\fn status_t BEntry::GetName(char* buffer) const
\brief Gets the name of the leaf of the BEntry object.
\c buffer must be pre-allocated and of sufficient length to hold the
entire string. A length of \c B_FILE_NAME_LENGTH is recommended.
\param buffer A pointer to a pre-allocated string into which the result
is copied.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn status_t BEntry::Rename(const char* path, bool clobber)
\brief Renames the BEntry to \a path replacing an existing entry
if \a clobber is \c true.
\note The BEntry object must refer to an existing file, if it is abstract,
this method will fail.
\param path A pointer to a string containing the new name for the entry.
It may be an absolute or relative path. If it is a relative path the
entry is renamed within its current directory.
\param clobber If \c false and a file with the name given by \c path
already exists, the method will fail. If \c true and such a file
exists, it will be overwritten.
\returns A status code.
\retval B_OK Success
\retval B_ENTRY_EXISTS The new location already exists and \c clobber
is \c false.
\retval B_ENTRY_NOT_FOUND Attempted to rename an abstract entry.
*/
/*!
\fn status_t BEntry::MoveTo(BDirectory* dir, const char* path,
bool clobber)
\brief Moves the BEntry to directory or directory and path combination,
replacing an existing entry if clobber is true.
\note The BEntry object must refer to an existing file, if it is abstract,
this method will fail.
\param dir A pointer to a pre-allocated BDirectory into which the entry
should be moved.
\param path (optional) new leaf name for the entry. May be a simple leaf
or a relative path; either way, \c path is reckoned off of \c dir. If
\c NULL, the entry retains its previous leaf name.
\param clobber If \c false and an entry already exists at the specified
destination, the method will fail. If \c true and such an entry exists,
it will be overwritten.
\returns A status code.
\retval B_OK Success
\retval B_ENTRY_EXISTS The new location already exists and \c clobber
is \c false.
\retval B_ENTRY_NOT_FOUND Attempted to rename an abstract entry.
*/
/*!
\fn status_t BEntry::Remove()
\brief Removes the entry from the file system.
\note If any file descriptors are open on the file when Remove() is called
the chunk of data they refer to will continue to exist until all such file
descriptors are closed. The BEntry object, however, becomes abstract and
no longer refers to any actual data in the filesystem.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn bool BEntry::operator==(const BEntry& item) const
\brief Returns \c true if the BEntry and \a item refer to the same entry
or if they are both uninitialized.
\retval true Both BEntry objects refer to the same entry or they are
both uninitialized.
\retval false The BEntry objects refer to different entries.
*/
/*!
\fn bool BEntry::operator!=(const BEntry& item) const
\brief Returns false if the BEntry and \c item refer to the same entry or
if they are both uninitialized.
\retval true The BEntry objects refer to different entries.
\retval false Both BEntry objects refer to the same entry or they are
both uninitialized.
*/
/*!
\fn BEntry& BEntry::operator=(const BEntry& item)
\brief Reinitializes the BEntry to be a copy of \a item.
\returns A pointer to the copy.
*/
/*!
\fn status_t BEntry::set_stat(struct stat& st, uint32 what)
\brief Updates the BEntry with the data from the stat structure according
to the \a what mask.
\param st The stat structure to set.
\param what A mask
\returns A status code.
\retval B_OK Everything went fine.
\retval B_FILE_ERROR There was an error writing to the BEntry object.
*/
/*!
\fn status_t BEntry::_SetTo(int dirFD, const char* path, bool traverse)
\brief Sets the entry to point to the entry specified by the path \a path
relative to the given directory.
If \a traverse is \c true and the given entry is a symbolic link, the
object is recursively set to point to the entry pointed to by the symlink.
If \a path is an absolute path, \a dirFD is ignored.
If \a dirFD is -1, \a path is considered relative to the current directory
(unless it is an absolute path).
The ownership of the file descriptor \a dirFD is transferred to the
method, regardless of whether it succeeds or fails. The caller must not
close the FD afterwards.
\param dirFD File descriptor of a directory relative to which path is to
be considered. May be -1 if the current directory shall be considered.
\param path Pointer to a path relative to the given directory.
\param traverse If \c true and the given entry is a symbolic link, the
object is recursively set to point to the entry linked to by the
symbolic link.
\returns \c B_OK on success, or an error code on failure.
*/
/*!
\fn status_t BEntry::_SetName(const char* name)
\brief Handles string allocation, deallocation, and copying for the
leaf name of the entry.
\param name The leaf \a name of the entry.
\returns A status code.
\retval B_OK Everything went fine.
\retval B_BAD_VALUE \a name is \c NULL.
\retval B_NO_MEMORY Ran out of memory trying to allocate \a name.
*/
/*!
\fn status_t BEntry::_Rename(BEntry& target, bool clobber)
\brief Renames the entry referred to by this object to the location
specified by \a target.
If an entry exists at the target location, the method fails, unless
\a clobber is \c true, in which case that entry is overwritten (doesn't
work for non-empty directories, though).
If the operation was successful, this entry is made a clone of the
supplied one and the supplied one is uninitialized.
\param target The entry specifying the target location.
\param clobber If \c true, the an entry existing at the target location
will be overwritten.
\return \c B_OK, if everything went fine, another error code otherwise.
*/
/*!
\fn void BEntry::_Dump(const char* name)
\brief Debugging function, dumps the given entry to stdout.
\param name A pointer to a string to be printed along with the dump for
identification purposes.
*/
/*!
\fn status_t get_ref_for_path(const char* path, entry_ref* ref)
\brief Returns an entry_ref for a given path.
\param path The path name referring to the entry.
\param ref The entry_ref structure to be filled in.
\returns A status code.
\retval B_OK Everything went fine.
\retval B_BAD_VALUE \c NULL \a path or \a ref.
\retval B_ENTRY_NOT_FOUND A (non-leaf) path component does not exist.
\retval B_NO_MEMORY Insufficient memory for successful completion.
*/
/*!
\fn bool operator<(const entry_ref& a, const entry_ref& b)
\brief Returns whether an entry is less than another.
The components are compared in order \c device, \c directory, \c name.
A \c NULL \c name is less than any non-<tt>NULL</tt> name.
\retval true a < b
\retval false a >= b
*/