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[osl.git] / osl.h.m4
1 VERBATIM_C(«
2 /*
3 * Copyright (C) 2007-2009 Andre Noll <maan@tuebingen.mpg.de>
4 *
5 * Licensed under the GPL v2. For licencing details see COPYING.
6 */
7
8 /* User interface for the object storage layer. */
9
10 #include <sys/mman.h>
11 #include <inttypes.h>
12
13 /* Export all declarations in this file. */
14 #pragma GCC visibility push(default)
15 »)
16
17 DECLARE_COMPOUND(
18 «struct osl_object»,
19 «Describes an object of the object storage layer.»,
20 «»,
21 «
22 «void *data», «Pointer to the data of the object.»,
23 «size_t size», «The object's size.»
24 »
25 )
26
27 DECLARE_ENUM(
28 «osl_table_flags»,
29 «Flags that change the internal handling of osl tables.»,
30 «»,
31 «
32 «OSL_LARGE_TABLE = 1»,
33 «This table will have many rows.»
34 »
35 )
36
37 DECLARE_ENUM(
38 «osl_storage_type»,
39 «The three different types of storage for an osl column.»,
40 «»,
41 «
42 «OSL_MAPPED_STORAGE»,
43 «All data for this column is stored in one file which gets mmapped
44 by osl_open_table(). This is suitable for columns that do not hold
45 much data.»,
46
47 «OSL_DISK_STORAGE»,
48 «Each entry is stored on disk and is loaded on demand by
49 open_disk_object(). This is the preferable storage type for large
50 objects that need not be in memory all the time.»,
51
52 «OSL_NO_STORAGE»,
53 «Objects for columns of this type are volatile: They are only stored
54 in memory and are discarded when the table is closed.»
55 »
56 )
57
58 DECLARE_ENUM(
59 «osl_storage_flags»,
60 «Additional per-column flags.»,
61 «»,
62 «
63 «OSL_RBTREE = 1»,
64 «Build an rbtree for this column. This is only possible if the storage
65 type of the column is either OSL_MAPPED_STORAGE or OSL_NO_STORAGE. In
66 order to lookup objects in the table by using osl_get_row(), the
67 lookup column must have an associated rbtree.
68
69 See also: osl_storage_type, osl_get_row()»,
70
71 «OSL_FIXED_SIZE = 2»,
72 «The data for this column will have constant size.»,
73
74 «OSL_UNIQUE = 4»,
75 «All values are different. Must be set if OSL_RBTREE is set.»,
76
77 «OSL_DONT_FREE = 8»,
78 «Do not free the data for this column (OSL_NO_STORAGE).»
79 »
80 )
81
82 STATEMENT(
83 «struct osl_table»,
84 «Opaque osl table structure.»
85 )
86
87 STATEMENT(
88 «struct osl_row»,
89 «Opaque osl row structure.»
90 )
91
92 STATEMENT(
93 «typedef int osl_compare_func(const struct osl_object *obj1, const struct osl_object *obj2)»,
94 «Comparator for rbtree nodes.»,
95 «To build an rbtree, a compare function for the objects must be
96 provided. This function takes pointers to the two objects to be
97 compared. It must return -1, zero, or 1, if the first argument is
98 considered to be respectively less than, equal to, or greater than
99 the second. If two members compare as equal, their order in the rbtree
100 is undefined.»
101 )
102
103 STATEMENT(
104 «typedef int osl_rbtree_loop_func(struct osl_row *row, void *data)»,
105 «Loop callback function.»,
106 «The osl_rbreee_loop functions take a function pointer of this
107 type. For each node in the rbtree, the given function is called.
108
109 See also: osl_rbtree_loop(), osl_rbtree_loop_reverse().»
110 )
111
112 DECLARE_COMPOUND(
113 «struct osl_column_description»,
114 «Describes one column of an osl table.»,
115 «», «
116 «uint16_t storage_type»,
117 «One of the three possible types of storage. See also:
118 osl_storage_type.»,
119
120 «uint16_t storage_flags»,
121 «Specifies further properties of the column. See also:
122 osl_storage_flags.»,
123
124 «char *name»,
125 «The column name determines the name of the directory where all
126 data for this column will be stored. Its hash is stored in the table
127 header. This field is ignored if the storage type is NO_STORAGE.»,
128
129 «osl_compare_func *compare_function»,
130 «For columns with an associated rbtree, this must point to a function
131 that compares the values of two objects, either a built-in function
132 or a function defined by the application may be supplied. This field
133 is ignored if the column does not have an associated rbtree.
134
135 See also: osl_storage_flags, osl_compare_func»,
136
137 «uint32_t data_size»,
138 «If the OSL_FIXED_SIZE flag is set for this column, this value
139 describes the number of bytes of each object of this column. It is
140 ignored, if OSL_FIXED_SIZE is not set.»
141 »
142 )
143
144 DECLARE_COMPOUND(
145 «struct osl_table_description»,
146 «Describes one osl table.»,
147 «A pointer to the table description is passed to osl_create_table()
148 and osl_open_table(). The osl library calls which operate on an
149 open table refer to the fields of the table description through this
150 pointer. Hence the table description must not be modified or freed
151 before the table is closed.»,
152
153 «
154 «const char *dir»,
155 «The directory which contains all files of this table. This may be
156 either relative to the cwd or an absolute path.»,
157
158 «const char *name»,
159 «The table name. A subdirectory of dir called name is created at
160 table creation time. It must be a valid name for a subdirectory.
161 In particular, no slashes are allowed in the name.»,
162
163 «uint16_t num_columns»,
164 «The number of columns of this table.»,
165
166 «uint8_t flags»,
167 «Further table-wide information, see osl_table_flags.»,
168
169 «struct osl_column_description *column_descriptions»,
170 «The array describing the individual columns of the table.»
171 »
172 )
173
174 DECLARE_ENUM(
175 «osl_close_flags»,
176 «Flags to be passed to osl_close_table().»,
177 «»,
178 «
179 «OSL_MARK_CLEAN = 1»,
180 «The table header contains a "dirty" flag which indicates whether the
181 table is currently held open by another process. The OSL_MARK_CLEAN
182 flag instructs libosl to clear the dirty flag when the table is
183 closed.»,
184
185 «OSL_FREE_VOLATILE = 2»,
186 «If the table contains columns of type OSL_NO_STORAGE and this flag
187 is passed to osl_close_table(), free(3) is called for each object of
188 each column of type OSL_NO_STORAGE.»
189 »
190 )
191
192 DECLARE_FUNCTION(
193 «osl_create_table»,
194 «Create a new osl table.»,
195 «»,
196 «
197 «const struct osl_table_description *desc»,
198 «Pointer to the table description»
199 »,
200 «»,
201 «int»,
202 «Standard»
203 )
204
205 DECLARE_FUNCTION(
206 «osl_open_table»,
207 «Open an osl table.»,
208 «An osl table must be opened before its data can be accessed.»,
209 «
210 «const struct osl_table_description *desc»,
211 «Describes the table to be opened»,
212
213 «struct osl_table **result»,
214 «Contains a pointer to the open table on success.»
215 »,
216 «The table description given by desc should coincide with the
217 description used at creation time.»,
218
219 «int»,
220 «Standard»
221 )
222
223 DECLARE_FUNCTION(
224 «osl_close_table»,
225 «Close an osl table.»,
226 «»,
227 «
228 «struct osl_table *t»,
229 «Pointer to the table to be closed.»,
230
231 «enum osl_close_flags flags»,
232 «Options for what should be cleaned up.»
233 »,
234 «If osl_open_table() succeeds, the resulting table pointer must
235 later be passed to this function in order to flush all changes to
236 the file system and to free the resources that were allocated by
237 osl_open_table().»,
238
239 «int»,
240 «Standard»
241 )
242
243 DECLARE_FUNCTION(
244 «osl_get_row»,
245 «Get the row that contains the given object.»,
246 «»,
247 «
248 «const struct osl_table *t»,
249 «Pointer to an open osl table»,
250
251 «unsigned col_num»,
252 «The number of the column to be searched»,
253
254 «const struct osl_object *obj»,
255 «The object to be looked up»,
256
257 «struct osl_row **result»,
258 «Points to the row containing the given object»
259 »,
260 «Lookup the given object and return the row containing it. The column
261 specified by col_num must have an associated rbtree.»,
262
263 «int»,
264 «Standard. The result pointer is set to NULL if and only if the
265 function returns negative.»
266 )
267
268 DECLARE_FUNCTION(
269 «osl_get_object»,
270 «Retrieve an object identified by row and column.»,
271 «»,
272 «
273 «const struct osl_table *t»,
274 «Pointer to an open osl table»,
275
276 «const struct osl_row *row»,
277 «Pointer to the row»,
278
279 «unsigned col_num»,
280 «The column number»,
281
282 «struct osl_object *object»,
283 «The result pointer»
284 »,
285 «The column determined by col_num must be of type OSL_MAPPED_STORAGE
286 or OSL_NO_STORAGE, i.e. no disk storage objects may be retrieved by
287 this function.
288
289 See also: osl_storage_type, osl_open_disk_object().»,
290 «int»,
291 «Standard»
292 )
293
294 DECLARE_FUNCTION(
295 «osl_open_disk_object»,
296 «Retrieve an object of type OSL_DISK_STORAGE by row and column.»,
297 «For columns of type OSL_DISK_STORAGE this function must be
298 used to retrieve one of its containing objects. Afterwards,
299 osl_close_disk_object() must be called in order to deallocate the
300 resources.»,
301
302 «
303 «const struct osl_table *t»,
304 «Pointer to an open osl table»,
305
306 «const struct osl_row *r»,
307 «Pointer to the row containing the object»,
308
309 «unsigned col_num»,
310 «The column number»,
311
312 «struct osl_object *obj»,
313 «Points to the result upon successful return»
314 »,
315 «See also: osl_get_object(), osl_storage_type,
316 osl_close_disk_object().»,
317
318 «int»,
319 «Standard»
320 )
321
322 DECLARE_FUNCTION(
323 «osl_close_disk_object»,
324 «Free resources allocated during osl_open_disk_object().», «
325 », «
326 «struct osl_object *obj»,
327 «Pointer to the object previously returned by open_disk_object()»
328 »,
329 «»,
330 «int», «The return value of the underlying call to munmap(2)»
331 )
332
333 DECLARE_FUNCTION(
334 «osl_add_and_get_row»,
335 «Add a new row to an osl table and retrieve this row.»,
336 «»,
337 «
338 «struct osl_table *t»,
339 «Pointer to an open osl table»,
340
341 «struct osl_object *objects»,
342 «Array of objects to be added»,
343
344 «struct osl_row **row»,
345 «Result pointer»
346 »,
347 «The objects parameter must point to an array containing one object
348 per column. The order of the objects in the array is given by the
349 table description of the table. Several sanity checks are performed
350 during object insertion and the function returns without modifying the
351 table if any of these tests fail. In fact, it is atomic in the sense
352 that it either succeeds or leaves the table unchanged (i.e. either
353 all or none of the objects are added to the table).
354
355 See also: struct osl_table_description, osl_compare_func,
356 osl_add_row().»,
357
358 «int»,
359 «Standard»
360 )
361
362 DECLARE_FUNCTION(
363 «osl_add_row»,
364 «Add a new row to an osl table.»,
365 «»,
366 «
367 «struct osl_table *t»,
368 «Same meaning as osl_add_and_get_row()»,
369
370 «struct osl_object *objects»,
371 «Same meaning as osl_add_and_get_row()»
372 »,
373 «This is equivalent to calling osl_add_and_get_row(t, objects,
374 NULL);»,
375
376 «int»,
377 «The return value of the underlying call to osl_add_and_get_row()»
378 )
379
380 DECLARE_FUNCTION(
381 «osl_del_row»,
382 «Delete a row from an osl table.»,
383 «»,
384 «
385 «struct osl_table *t»,
386 «Pointer to an open osl table»,
387
388 «struct osl_row *row»,
389 «Pointer to the row to delete»
390 »,
391 «This removes all disk storage objects, removes all rbtree nodes,
392 and frees all volatile objects belonging to the given row. For mapped
393 columns, the data is merely marked invalid and may be pruned from
394 time to time by oslfsck(1).»,
395
396 «int»,
397 «Standard»
398 )
399
400 DECLARE_FUNCTION(
401 «osl_rbtree_loop»,
402 «Loop over all nodes in an rbtree.»,
403 «»,
404 «
405 «const struct osl_table *t»,
406 «Pointer to an open osl table»,
407
408 «unsigned col_num»,
409 «The column to use for iterating over the elements»,
410
411 «void *private_data»,
412 «Pointer that gets passed to the callback function»,
413
414 «osl_rbtree_loop_func *func»,
415 «This callback is called for each node in the rbtree.»
416 »,
417 «This function does an in-order walk of the rbtree associated with
418 col_num. It is an error if the OSL_RBTREE flag is not set for this
419 column. For each node in the rbtree, the given function func is called
420 with two pointers as arguments: The first osl_row* argument points
421 to the row that contains the object corresponding to the rbtree node
422 currently traversed, and the private_data pointer is passed verbatim as
423 the second argument. The loop terminates either if the callback returns
424 a negative value, or if all nodes of the tree have been visited.»,
425
426 «int»,
427 «Standard. If the termination of the loop was caused by the callback
428 returning a negative value, -E_OSL_LOOP is returned. This is the only
429 possible error.»
430 )
431
432 DECLARE_FUNCTION(
433 «osl_rbtree_loop_reverse»,
434 «Loop over all nodes in an rbtree in reverse order.»,
435 «This function is identical to osl_rbtree_loop(), the only difference
436 is that the tree is walked in reverse order.»,
437 «
438 «const struct osl_table *t»,
439 «See osl_rbtree_loop()»,
440
441 «unsigned col_num»,
442 «See osl_rbtree_loop()»,
443
444 «void *private_data»,
445 «See osl_rbtree_loop()»,
446
447 «osl_rbtree_loop_func *func»,
448 «See osl_rbtree_loop()»
449 »,
450 «See also: osl_rbtree_loop().»,
451 «int»,
452 «The same return value as osl_rbtree_loop()»
453 )
454
455 DECLARE_FUNCTION(
456 «osl_update_object»,
457 «Change an object of an osl table.»,
458 «»,
459 «
460 «struct osl_table *t»,
461 «Pointer to an open osl table»,
462
463 «const struct osl_row *r»,
464 «Pointer to the row containing the object to be updated»,
465
466 «unsigned col_num»,
467 «Number of the column containing the object to be updated»,
468
469 «struct osl_object *obj»,
470 «Pointer to the replacement object»
471 »,
472 «This function gets rid of all references to the old object. This
473 includes removal of the rbtree node in case there is an rbtree
474 associated with col_num. It then inserts obj into the table and the
475 rbtree if necessary.»,
476
477 «int»,
478 «Standard»
479 )
480
481 DECLARE_FUNCTION(
482 «osl_get_num_rows»,
483 «Get the number of rows of the given table.»,
484 «»,
485 «
486 «const struct osl_table *t»,
487 «Pointer to an open osl table»,
488
489 «unsigned *num_rows»,
490 «Result is returned here»
491 »,
492 «The number of rows returned excludes any invalid rows.»,
493
494 «int»,
495 «Positive on success, -E_OSL_BAD_TABLE if t is NULL»
496 )
497
498 DECLARE_FUNCTION(
499 «osl_rbtree_first_row»,
500 «Get the row corresponding to the smallest rbtree node of a column.»,
501 «»,
502 «
503 «const struct osl_table *t»,
504 «An open table»,
505
506 «unsigned col_num»,
507 «The number of the rbtree column»,
508
509 «struct osl_row **result»,
510 «A pointer to the first row is returned here»
511 »,
512 «The rbtree node of the smallest object (with respect to the
513 corresponding compare function) is selected and the row containing
514 this object is returned. It is an error if col_num refers to a column
515 without an associated rbtree.
516
517 See also: osl_get_nth_row(), osl_rbtree_last_row().»,
518 «int»,
519 «Standard»
520 )
521
522 DECLARE_FUNCTION(
523 «osl_rbtree_last_row»,
524 «Get the row corresponding to the greatest rbtree node of a column.»,
525 «This function works just like osl_rbtree_first_row(), the only
526 difference is that the row containing the greatest rather than the
527 smallest object is returned.»,
528
529 «
530 «const struct osl_table *t»,
531 «See osl_rbtree_first_row()»,
532
533 «unsigned col_num»,
534 «See osl_rbtree_first_row()»,
535
536 «struct osl_row **result»,
537 «See osl_rbtree_first_row()»
538 »,
539 «See also: osl_get_nth_row(), osl_rbtree_first_row()»,
540 «int»,
541 «Standard»
542 )
543
544 DECLARE_FUNCTION(
545 «osl_get_nth_row»,
546 «Get the row with n-th greatest value.»,
547 «»,
548 «
549 «const struct osl_table *t»,
550 «Pointer to an open osl table»,
551
552 «unsigned col_num»,
553 «The column number»,
554
555 «unsigned n»,
556 «The rank of the desired row»,
557
558 «struct osl_row **result»,
559 «Row is returned here»
560 »,
561 «Retrieve the n-th order statistic with respect to the compare
562 function of the rbtree column col_num. In other words, get the row
563 with n-th greatest value in column col_num. It is an error if col_num
564 is not a rbtree column, or if n is larger than the number of rows in
565 the table.»,
566
567 «int»,
568 «Standard»
569 )
570
571 DECLARE_FUNCTION(
572 «osl_get_rank»,
573 «Get the rank of a row.»,
574 «The rank is, by definition, the position of the row in the linear
575 order determined by an in-order tree walk of the rbtree associated
576 with given column number.»,
577
578 «
579 «const struct osl_table *t»,
580 «An open osl table»,
581
582 «struct osl_row *r»,
583 «The row to get the rank of»,
584
585 «unsigned col_num»,
586 «The number of an rbtree column»,
587
588 «unsigned *rank»,
589 «Result pointer»
590 »,
591 «See also: osl_get_nth_row().»,
592 «int»,
593 «Standard»
594 )
595
596 DECLARE_FUNCTION(
597 «osl_strerror»,
598 «Get a string describing the error code passed in the argument.»,
599 «»,
600 «
601 «int num»,
602 «The error code»
603 »,
604 «This works just like strerror(3). The given number must be an osl
605 error code. The result must not be freed by the caller.»,
606
607 «const char *»,
608 «The error text corresponding to an osl error code»
609 )
610
611 VERBATIM_C(«
612 #pragma GCC visibility pop
613 »)