Fix: Coverity warning CWE-457: Use of Uninitialized Variable
[babeltrace.git] / lib / iterator.c
1 /*
2 * iterator.c
3 *
4 * Babeltrace Library
5 *
6 * Copyright 2010-2011 EfficiOS Inc. and Linux Foundation
7 *
8 * Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
9 *
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
16 *
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
23 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
26 * SOFTWARE.
27 */
28
29 #include <stdlib.h>
30 #include <babeltrace/babeltrace.h>
31 #include <babeltrace/context.h>
32 #include <babeltrace/context-internal.h>
33 #include <babeltrace/iterator-internal.h>
34 #include <babeltrace/iterator.h>
35 #include <babeltrace/prio_heap.h>
36 #include <babeltrace/ctf/metadata.h>
37 #include <babeltrace/ctf/events.h>
38 #include <inttypes.h>
39
40 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
41 const struct bt_iter_pos *begin_pos,
42 unsigned long stream_id);
43
44 struct stream_saved_pos {
45 /*
46 * Use file_stream pointer to check if the trace collection we
47 * restore to match the one we saved from, for each stream.
48 */
49 struct ctf_file_stream *file_stream;
50 size_t cur_index; /* current index in packet index */
51 ssize_t offset; /* offset from base, in bits. EOF for end of file. */
52 uint64_t current_real_timestamp;
53 uint64_t current_cycles_timestamp;
54 };
55
56 struct bt_saved_pos {
57 struct trace_collection *tc;
58 GArray *stream_saved_pos; /* Contains struct stream_saved_pos */
59 };
60
61 static int stream_read_event(struct ctf_file_stream *sin)
62 {
63 int ret;
64
65 ret = sin->pos.parent.event_cb(&sin->pos.parent, &sin->parent);
66 if (ret == EOF)
67 return EOF;
68 else if (ret == EAGAIN)
69 /* Stream is inactive for now (live reading). */
70 return EAGAIN;
71 else if (ret) {
72 fprintf(stderr, "[error] Reading event failed.\n");
73 return ret;
74 }
75 return 0;
76 }
77
78 /*
79 * Return true if a < b, false otherwise.
80 * If time stamps are exactly the same, compare by stream path. This
81 * ensures we get the same result between runs on the same trace
82 * collection on different environments.
83 * The result will be random for memory-mapped traces since there is no
84 * fixed path leading to those (they have empty path string).
85 */
86 static int stream_compare(void *a, void *b)
87 {
88 struct ctf_file_stream *s_a = a, *s_b = b;
89
90 if (s_a->parent.real_timestamp < s_b->parent.real_timestamp) {
91 return 1;
92 } else if (likely(s_a->parent.real_timestamp > s_b->parent.real_timestamp)) {
93 return 0;
94 } else {
95 return strcmp(s_a->parent.path, s_b->parent.path);
96 }
97 }
98
99 void bt_iter_free_pos(struct bt_iter_pos *iter_pos)
100 {
101 if (!iter_pos)
102 return;
103
104 if (iter_pos->type == BT_SEEK_RESTORE && iter_pos->u.restore) {
105 if (iter_pos->u.restore->stream_saved_pos) {
106 g_array_free(
107 iter_pos->u.restore->stream_saved_pos,
108 TRUE);
109 }
110 g_free(iter_pos->u.restore);
111 }
112 g_free(iter_pos);
113 }
114
115 /*
116 * seek_file_stream_by_timestamp
117 *
118 * Browse a filestream by index, if an index contains the timestamp passed in
119 * argument, seek inside the corresponding packet it until we find the event we
120 * are looking for (either the exact timestamp or the event just after the
121 * timestamp).
122 *
123 * Return 0 if the seek succeded, EOF if we didn't find any packet
124 * containing the timestamp, or a positive integer for error.
125 *
126 * TODO: this should be turned into a binary search! It is currently
127 * doing a linear search in the packets. This is a O(n) operation on a
128 * very frequent code path.
129 */
130 static int seek_file_stream_by_timestamp(struct ctf_file_stream *cfs,
131 uint64_t timestamp)
132 {
133 struct ctf_stream_pos *stream_pos;
134 struct packet_index *index;
135 int i, ret;
136
137 stream_pos = &cfs->pos;
138 for (i = 0; i < stream_pos->packet_index->len; i++) {
139 index = &g_array_index(stream_pos->packet_index,
140 struct packet_index, i);
141 if (index->ts_real.timestamp_end < timestamp)
142 continue;
143
144 stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
145 do {
146 ret = stream_read_event(cfs);
147 } while (cfs->parent.real_timestamp < timestamp && ret == 0);
148
149 /* Can return either EOF, 0, or error (> 0). */
150 return ret;
151 }
152 /*
153 * Cannot find the timestamp within the stream packets, return
154 * EOF.
155 */
156 return EOF;
157 }
158
159 /*
160 * seek_ctf_trace_by_timestamp : for each file stream, seek to the event with
161 * the corresponding timestamp
162 *
163 * Return 0 on success.
164 * If the timestamp is not part of any file stream, return EOF to inform the
165 * user the timestamp is out of the scope.
166 * On other errors, return positive value.
167 */
168 static int seek_ctf_trace_by_timestamp(struct ctf_trace *tin,
169 uint64_t timestamp, struct ptr_heap *stream_heap)
170 {
171 int i, j, ret;
172 int found = 0;
173
174 /* for each stream_class */
175 for (i = 0; i < tin->streams->len; i++) {
176 struct ctf_stream_declaration *stream_class;
177
178 stream_class = g_ptr_array_index(tin->streams, i);
179 if (!stream_class)
180 continue;
181 /* for each file_stream */
182 for (j = 0; j < stream_class->streams->len; j++) {
183 struct ctf_stream_definition *stream;
184 struct ctf_file_stream *cfs;
185
186 stream = g_ptr_array_index(stream_class->streams, j);
187 if (!stream)
188 continue;
189 cfs = container_of(stream, struct ctf_file_stream,
190 parent);
191 ret = seek_file_stream_by_timestamp(cfs, timestamp);
192 if (ret == 0) {
193 /* Add to heap */
194 ret = bt_heap_insert(stream_heap, cfs);
195 if (ret) {
196 /* Return positive error. */
197 return -ret;
198 }
199 found = 1;
200 } else if (ret > 0) {
201 /*
202 * Error in seek (not EOF), failure.
203 */
204 return ret;
205 }
206 /* on EOF just do not put stream into heap. */
207 }
208 }
209
210 return found ? 0 : EOF;
211 }
212
213 /*
214 * Find timestamp of last event in the stream.
215 *
216 * Return value: 0 if OK, positive error value on error, EOF if no
217 * events were found.
218 */
219 static int find_max_timestamp_ctf_file_stream(struct ctf_file_stream *cfs,
220 uint64_t *timestamp_end)
221 {
222 int ret, count = 0, i;
223 uint64_t timestamp = 0;
224 struct ctf_stream_pos *stream_pos;
225
226 stream_pos = &cfs->pos;
227 /*
228 * We start by the last packet, and iterate backwards until we
229 * either find at least one event, or we reach the first packet
230 * (some packets can be empty).
231 */
232 for (i = stream_pos->packet_index->len - 1; i >= 0; i--) {
233 stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
234 count = 0;
235 /* read each event until we reach the end of the stream */
236 do {
237 ret = stream_read_event(cfs);
238 if (ret == 0) {
239 count++;
240 timestamp = cfs->parent.real_timestamp;
241 }
242 } while (ret == 0);
243
244 /* Error */
245 if (ret > 0)
246 goto end;
247 assert(ret == EOF);
248 if (count)
249 break;
250 }
251
252 if (count) {
253 *timestamp_end = timestamp;
254 ret = 0;
255 } else {
256 /* Return EOF if no events were found */
257 ret = EOF;
258 }
259 end:
260 return ret;
261 }
262
263 /*
264 * Find the stream within a stream class that contains the event with
265 * the largest timestamp, and save that timestamp.
266 *
267 * Return 0 if OK, EOF if no events were found in the streams, or
268 * positive value on error.
269 */
270 static int find_max_timestamp_ctf_stream_class(
271 struct ctf_stream_declaration *stream_class,
272 struct ctf_file_stream **cfsp,
273 uint64_t *max_timestamp)
274 {
275 int ret = EOF, i, found = 0;
276
277 for (i = 0; i < stream_class->streams->len; i++) {
278 struct ctf_stream_definition *stream;
279 struct ctf_file_stream *cfs;
280 uint64_t current_max_ts = 0;
281
282 stream = g_ptr_array_index(stream_class->streams, i);
283 if (!stream)
284 continue;
285 cfs = container_of(stream, struct ctf_file_stream, parent);
286 ret = find_max_timestamp_ctf_file_stream(cfs, &current_max_ts);
287 if (ret == EOF)
288 continue;
289 if (ret != 0)
290 break;
291 if (current_max_ts >= *max_timestamp) {
292 *max_timestamp = current_max_ts;
293 *cfsp = cfs;
294 found = 1;
295 }
296 }
297 assert(ret >= 0 || ret == EOF);
298 if (found) {
299 return 0;
300 }
301 return ret;
302 }
303
304 /*
305 * seek_last_ctf_trace_collection: seek trace collection to last event.
306 *
307 * Return 0 if OK, EOF if no events were found, or positive error value
308 * on error.
309 */
310 static int seek_last_ctf_trace_collection(struct trace_collection *tc,
311 struct ctf_file_stream **cfsp)
312 {
313 int i, j, ret;
314 int found = 0;
315 uint64_t max_timestamp = 0;
316
317 if (!tc)
318 return 1;
319
320 /* For each trace in the trace_collection */
321 for (i = 0; i < tc->array->len; i++) {
322 struct ctf_trace *tin;
323 struct bt_trace_descriptor *td_read;
324
325 td_read = g_ptr_array_index(tc->array, i);
326 if (!td_read)
327 continue;
328 tin = container_of(td_read, struct ctf_trace, parent);
329 /* For each stream_class in the trace */
330 for (j = 0; j < tin->streams->len; j++) {
331 struct ctf_stream_declaration *stream_class;
332
333 stream_class = g_ptr_array_index(tin->streams, j);
334 if (!stream_class)
335 continue;
336 ret = find_max_timestamp_ctf_stream_class(stream_class,
337 cfsp, &max_timestamp);
338 if (ret > 0)
339 goto end;
340 if (ret == 0)
341 found = 1;
342 assert(ret == EOF || ret == 0);
343 }
344 }
345 /*
346 * Now we know in which file stream the last event is located,
347 * and we know its timestamp.
348 */
349 if (!found) {
350 ret = EOF;
351 } else {
352 ret = seek_file_stream_by_timestamp(*cfsp, max_timestamp);
353 assert(ret == 0);
354 }
355 end:
356 return ret;
357 }
358
359 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *iter_pos)
360 {
361 struct trace_collection *tc;
362 int i, ret;
363
364 if (!iter || !iter_pos)
365 return -EINVAL;
366
367 switch (iter_pos->type) {
368 case BT_SEEK_RESTORE:
369 if (!iter_pos->u.restore)
370 return -EINVAL;
371
372 bt_heap_free(iter->stream_heap);
373 ret = bt_heap_init(iter->stream_heap, 0, stream_compare);
374 if (ret < 0)
375 goto error_heap_init;
376
377 for (i = 0; i < iter_pos->u.restore->stream_saved_pos->len;
378 i++) {
379 struct stream_saved_pos *saved_pos;
380 struct ctf_stream_pos *stream_pos;
381 struct ctf_stream_definition *stream;
382
383 saved_pos = &g_array_index(
384 iter_pos->u.restore->stream_saved_pos,
385 struct stream_saved_pos, i);
386 stream = &saved_pos->file_stream->parent;
387 stream_pos = &saved_pos->file_stream->pos;
388
389 stream_pos->packet_seek(&stream_pos->parent,
390 saved_pos->cur_index, SEEK_SET);
391
392 /*
393 * the timestamp needs to be restored after
394 * packet_seek, because this function resets
395 * the timestamp to the beginning of the packet
396 */
397 stream->real_timestamp = saved_pos->current_real_timestamp;
398 stream->cycles_timestamp = saved_pos->current_cycles_timestamp;
399 stream_pos->offset = saved_pos->offset;
400 stream_pos->last_offset = LAST_OFFSET_POISON;
401
402 stream->prev_real_timestamp = 0;
403 stream->prev_real_timestamp_end = 0;
404 stream->prev_cycles_timestamp = 0;
405 stream->prev_cycles_timestamp_end = 0;
406
407 printf_debug("restored to cur_index = %" PRId64 " and "
408 "offset = %" PRId64 ", timestamp = %" PRIu64 "\n",
409 stream_pos->cur_index,
410 stream_pos->offset, stream->real_timestamp);
411
412 ret = stream_read_event(saved_pos->file_stream);
413 if (ret != 0) {
414 goto error;
415 }
416
417 /* Add to heap */
418 ret = bt_heap_insert(iter->stream_heap,
419 saved_pos->file_stream);
420 if (ret)
421 goto error;
422 }
423 return 0;
424 case BT_SEEK_TIME:
425 tc = iter->ctx->tc;
426
427 bt_heap_free(iter->stream_heap);
428 ret = bt_heap_init(iter->stream_heap, 0, stream_compare);
429 if (ret < 0)
430 goto error_heap_init;
431
432 /* for each trace in the trace_collection */
433 for (i = 0; i < tc->array->len; i++) {
434 struct ctf_trace *tin;
435 struct bt_trace_descriptor *td_read;
436
437 td_read = g_ptr_array_index(tc->array, i);
438 if (!td_read)
439 continue;
440 tin = container_of(td_read, struct ctf_trace, parent);
441
442 ret = seek_ctf_trace_by_timestamp(tin,
443 iter_pos->u.seek_time,
444 iter->stream_heap);
445 /*
446 * Positive errors are failure. Negative value
447 * is EOF (for which we continue with other
448 * traces). 0 is success. Note: on EOF, it just
449 * means that no stream has been added to the
450 * iterator for that trace, which is fine.
451 */
452 if (ret != 0 && ret != EOF)
453 goto error;
454 }
455 return 0;
456 case BT_SEEK_BEGIN:
457 tc = iter->ctx->tc;
458 bt_heap_free(iter->stream_heap);
459 ret = bt_heap_init(iter->stream_heap, 0, stream_compare);
460 if (ret < 0)
461 goto error_heap_init;
462
463 for (i = 0; i < tc->array->len; i++) {
464 struct ctf_trace *tin;
465 struct bt_trace_descriptor *td_read;
466 int stream_id;
467
468 td_read = g_ptr_array_index(tc->array, i);
469 if (!td_read)
470 continue;
471 tin = container_of(td_read, struct ctf_trace, parent);
472
473 /* Populate heap with each stream */
474 for (stream_id = 0; stream_id < tin->streams->len;
475 stream_id++) {
476 struct ctf_stream_declaration *stream;
477 int filenr;
478
479 stream = g_ptr_array_index(tin->streams,
480 stream_id);
481 if (!stream)
482 continue;
483 for (filenr = 0; filenr < stream->streams->len;
484 filenr++) {
485 struct ctf_file_stream *file_stream;
486 file_stream = g_ptr_array_index(
487 stream->streams,
488 filenr);
489 if (!file_stream)
490 continue;
491 ret = babeltrace_filestream_seek(
492 file_stream, iter_pos,
493 stream_id);
494 if (ret != 0 && ret != EOF) {
495 goto error;
496 }
497 if (ret == EOF) {
498 /* Do not add EOF streams */
499 continue;
500 }
501 ret = bt_heap_insert(iter->stream_heap, file_stream);
502 if (ret)
503 goto error;
504 }
505 }
506 }
507 break;
508 case BT_SEEK_LAST:
509 {
510 struct ctf_file_stream *cfs = NULL;
511
512 tc = iter->ctx->tc;
513 ret = seek_last_ctf_trace_collection(tc, &cfs);
514 if (ret != 0 || !cfs)
515 goto error;
516 /* remove all streams from the heap */
517 bt_heap_free(iter->stream_heap);
518 /* Create a new empty heap */
519 ret = bt_heap_init(iter->stream_heap, 0, stream_compare);
520 if (ret < 0)
521 goto error;
522 /* Insert the stream that contains the last event */
523 ret = bt_heap_insert(iter->stream_heap, cfs);
524 if (ret)
525 goto error;
526 break;
527 }
528 default:
529 /* not implemented */
530 return -EINVAL;
531 }
532
533 return 0;
534
535 error:
536 bt_heap_free(iter->stream_heap);
537 error_heap_init:
538 if (bt_heap_init(iter->stream_heap, 0, stream_compare) < 0) {
539 bt_heap_free(iter->stream_heap);
540 g_free(iter->stream_heap);
541 iter->stream_heap = NULL;
542 ret = -ENOMEM;
543 }
544
545 return ret;
546 }
547
548 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
549 {
550 struct bt_iter_pos *pos;
551 struct trace_collection *tc;
552 struct ctf_file_stream *file_stream = NULL, *removed;
553 struct ptr_heap iter_heap_copy;
554 int ret;
555
556 if (!iter)
557 return NULL;
558
559 tc = iter->ctx->tc;
560 pos = g_new0(struct bt_iter_pos, 1);
561 pos->type = BT_SEEK_RESTORE;
562 pos->u.restore = g_new0(struct bt_saved_pos, 1);
563 pos->u.restore->tc = tc;
564 pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
565 sizeof(struct stream_saved_pos));
566 if (!pos->u.restore->stream_saved_pos)
567 goto error;
568
569 ret = bt_heap_copy(&iter_heap_copy, iter->stream_heap);
570 if (ret < 0)
571 goto error_heap;
572
573 /* iterate over each stream in the heap */
574 file_stream = bt_heap_maximum(&iter_heap_copy);
575 while (file_stream != NULL) {
576 struct stream_saved_pos saved_pos;
577
578 assert(file_stream->pos.last_offset != LAST_OFFSET_POISON);
579 saved_pos.offset = file_stream->pos.last_offset;
580 saved_pos.file_stream = file_stream;
581 saved_pos.cur_index = file_stream->pos.cur_index;
582
583 saved_pos.current_real_timestamp = file_stream->parent.real_timestamp;
584 saved_pos.current_cycles_timestamp = file_stream->parent.cycles_timestamp;
585
586 g_array_append_val(
587 pos->u.restore->stream_saved_pos,
588 saved_pos);
589
590 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
591 "offset : %zd, "
592 "timestamp = %" PRIu64 "\n",
593 file_stream->parent.stream_id,
594 saved_pos.cur_index, saved_pos.offset,
595 saved_pos.current_real_timestamp);
596
597 /* remove the stream from the heap copy */
598 removed = bt_heap_remove(&iter_heap_copy);
599 assert(removed == file_stream);
600
601 file_stream = bt_heap_maximum(&iter_heap_copy);
602 }
603 bt_heap_free(&iter_heap_copy);
604 return pos;
605
606 error_heap:
607 g_array_free(pos->u.restore->stream_saved_pos, TRUE);
608 error:
609 g_free(pos);
610 return NULL;
611 }
612
613 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
614 uint64_t timestamp)
615 {
616 struct bt_iter_pos *pos;
617
618 if (!iter)
619 return NULL;
620
621 pos = g_new0(struct bt_iter_pos, 1);
622 pos->type = BT_SEEK_TIME;
623 pos->u.seek_time = timestamp;
624 return pos;
625 }
626
627 /*
628 * babeltrace_filestream_seek: seek a filestream to given position.
629 *
630 * The stream_id parameter is only useful for BT_SEEK_RESTORE.
631 */
632 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
633 const struct bt_iter_pos *begin_pos,
634 unsigned long stream_id)
635 {
636 int ret = 0;
637
638 if (!file_stream || !begin_pos)
639 return -EINVAL;
640
641 switch (begin_pos->type) {
642 case BT_SEEK_CUR:
643 /*
644 * just insert into the heap we should already know
645 * the timestamps
646 */
647 break;
648 case BT_SEEK_BEGIN:
649 file_stream->pos.packet_seek(&file_stream->pos.parent,
650 0, SEEK_SET);
651 ret = stream_read_event(file_stream);
652 break;
653 case BT_SEEK_TIME:
654 case BT_SEEK_RESTORE:
655 default:
656 assert(0); /* Not yet defined */
657 }
658
659 return ret;
660 }
661
662 int bt_iter_add_trace(struct bt_iter *iter,
663 struct bt_trace_descriptor *td_read)
664 {
665 struct ctf_trace *tin;
666 int stream_id, ret = 0;
667
668 tin = container_of(td_read, struct ctf_trace, parent);
669
670 /* Populate heap with each stream */
671 for (stream_id = 0; stream_id < tin->streams->len;
672 stream_id++) {
673 struct ctf_stream_declaration *stream;
674 int filenr;
675
676 stream = g_ptr_array_index(tin->streams, stream_id);
677 if (!stream)
678 continue;
679 for (filenr = 0; filenr < stream->streams->len;
680 filenr++) {
681 struct ctf_file_stream *file_stream;
682 struct bt_iter_pos pos;
683
684 file_stream = g_ptr_array_index(stream->streams,
685 filenr);
686 if (!file_stream)
687 continue;
688
689 pos.type = BT_SEEK_BEGIN;
690 ret = babeltrace_filestream_seek(file_stream,
691 &pos, stream_id);
692
693 if (ret == EOF) {
694 ret = 0;
695 continue;
696 } else if (ret != 0 && ret != EAGAIN) {
697 goto error;
698 }
699 /* Add to heap */
700 ret = bt_heap_insert(iter->stream_heap, file_stream);
701 if (ret)
702 goto error;
703 }
704 }
705
706 error:
707 return ret;
708 }
709
710 int bt_iter_init(struct bt_iter *iter,
711 struct bt_context *ctx,
712 const struct bt_iter_pos *begin_pos,
713 const struct bt_iter_pos *end_pos)
714 {
715 int i;
716 int ret = 0;
717
718 if (!iter || !ctx)
719 return -EINVAL;
720
721 if (ctx->current_iterator) {
722 ret = -1;
723 goto error_ctx;
724 }
725
726 iter->stream_heap = g_new(struct ptr_heap, 1);
727 iter->end_pos = end_pos;
728 bt_context_get(ctx);
729 iter->ctx = ctx;
730
731 ret = bt_heap_init(iter->stream_heap, 0, stream_compare);
732 if (ret < 0)
733 goto error_heap_init;
734
735 for (i = 0; i < ctx->tc->array->len; i++) {
736 struct bt_trace_descriptor *td_read;
737
738 td_read = g_ptr_array_index(ctx->tc->array, i);
739 if (!td_read)
740 continue;
741 ret = bt_iter_add_trace(iter, td_read);
742 if (ret < 0)
743 goto error;
744 }
745
746 ctx->current_iterator = iter;
747 if (begin_pos && begin_pos->type != BT_SEEK_BEGIN) {
748 ret = bt_iter_set_pos(iter, begin_pos);
749 }
750
751 return ret;
752
753 error:
754 bt_heap_free(iter->stream_heap);
755 error_heap_init:
756 g_free(iter->stream_heap);
757 iter->stream_heap = NULL;
758 error_ctx:
759 return ret;
760 }
761
762 struct bt_iter *bt_iter_create(struct bt_context *ctx,
763 const struct bt_iter_pos *begin_pos,
764 const struct bt_iter_pos *end_pos)
765 {
766 struct bt_iter *iter;
767 int ret;
768
769 if (!ctx)
770 return NULL;
771
772 iter = g_new0(struct bt_iter, 1);
773 ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
774 if (ret) {
775 g_free(iter);
776 return NULL;
777 }
778 return iter;
779 }
780
781 void bt_iter_fini(struct bt_iter *iter)
782 {
783 assert(iter);
784 if (iter->stream_heap) {
785 bt_heap_free(iter->stream_heap);
786 g_free(iter->stream_heap);
787 }
788 iter->ctx->current_iterator = NULL;
789 bt_context_put(iter->ctx);
790 }
791
792 void bt_iter_destroy(struct bt_iter *iter)
793 {
794 assert(iter);
795 bt_iter_fini(iter);
796 g_free(iter);
797 }
798
799 int bt_iter_next(struct bt_iter *iter)
800 {
801 struct ctf_file_stream *file_stream, *removed;
802 int ret;
803
804 if (!iter)
805 return -EINVAL;
806
807 file_stream = bt_heap_maximum(iter->stream_heap);
808 if (!file_stream) {
809 /* end of file for all streams */
810 ret = 0;
811 goto end;
812 }
813
814 ret = stream_read_event(file_stream);
815 if (ret == EOF) {
816 removed = bt_heap_remove(iter->stream_heap);
817 assert(removed == file_stream);
818 ret = 0;
819 goto end;
820 } else if (ret == EAGAIN) {
821 /*
822 * Live streaming: the stream is inactive for now, we
823 * just updated the timestamp_end to skip over this
824 * stream up to a certain point in time.
825 *
826 * Since we can't guarantee that a stream will ever have
827 * any activity, we can't rely on the fact that
828 * bt_iter_next will be called for each stream and deal
829 * with inactive streams. So instead, we return 0 here
830 * to the caller and let the read API handle the
831 * retry case.
832 */
833 ret = 0;
834 goto reinsert;
835 } else if (ret) {
836 goto end;
837 }
838
839 reinsert:
840 /* Reinsert the file stream into the heap, and rebalance. */
841 removed = bt_heap_replace_max(iter->stream_heap, file_stream);
842 assert(removed == file_stream);
843 end:
844 return ret;
845 }
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