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
  21 #include <stdlib.h>
  22 #include <babeltrace/babeltrace.h>
  23 #include <babeltrace/context.h>
  24 #include <babeltrace/context-internal.h>
  25 #include <babeltrace/iterator-internal.h>
  26 #include <babeltrace/iterator.h>
  27 #include <babeltrace/prio_heap.h>
  28 #include <babeltrace/ctf/metadata.h>
  29 #include <babeltrace/ctf/events.h>
  30 #include <inttypes.h>
  31
  32 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
  33                 const struct bt_iter_pos *begin_pos,
  34                 unsigned long stream_id);
  35
  36 struct stream_saved_pos {
  37         /*
  38          * Use file_stream pointer to check if the trace collection we
  39          * restore to match the one we saved from, for each stream.
  40          */
  41         struct ctf_file_stream *file_stream;
  42         size_t cur_index;       /* current index in packet index */
  43         ssize_t offset;         /* offset from base, in bits. EOF for end of file. */
  44         uint64_t current_timestamp;
  45 };
  46
  47 struct bt_saved_pos {
  48         struct trace_collection *tc;
  49         GArray *stream_saved_pos;       /* Contains struct stream_saved_pos */
  50 };
  51
  52 static int stream_read_event(struct ctf_file_stream *sin)
  53 {
  54         int ret;
  55
  56         ret = sin->pos.parent.event_cb(&sin->pos.parent, &sin->parent);
  57         if (ret == EOF)
  58                 return EOF;
  59         else if (ret) {
  60                 fprintf(stderr, "[error] Reading event failed.\n");
  61                 return ret;
  62         }
  63         return 0;
  64 }
  65
  66 /*
  67  * returns true if a < b, false otherwise.
  68  */
  69 int stream_compare(void *a, void *b)
  70 {
  71         struct ctf_file_stream *s_a = a, *s_b = b;
  72
  73         if (s_a->parent.timestamp < s_b->parent.timestamp)
  74                 return 1;
  75         else
  76                 return 0;
  77 }
  78
  79 void bt_iter_free_pos(struct bt_iter_pos *iter_pos)
  80 {
  81         if (!iter_pos)
  82                 return;
  83
  84         if (iter_pos->type == BT_SEEK_RESTORE && iter_pos->u.restore) {
  85                 if (iter_pos->u.restore->stream_saved_pos) {
  86                         g_array_free(
  87                                 iter_pos->u.restore->stream_saved_pos,
  88                                 TRUE);
  89                 }
  90                 g_free(iter_pos->u.restore);
  91         }
  92         g_free(iter_pos);
  93 }
  94
  95 /*
  96  * seek_file_stream_by_timestamp
  97  *
  98  * Browse a filestream by index, if an index contains the timestamp passed in
  99  * argument, seek inside the corresponding packet it until we find the event we
 100  * are looking for (either the exact timestamp or the event just after the
 101  * timestamp).
 102  *
 103  * Return 0 if the seek succeded, EOF if we didn't find any packet
 104  * containing the timestamp, or a positive integer for error.
 105  */
 106 static int seek_file_stream_by_timestamp(struct ctf_file_stream *cfs,
 107                 uint64_t timestamp)
 108 {
 109         struct ctf_stream_pos *stream_pos;
 110         struct packet_index *index;
 111         int i, ret;
 112
 113         stream_pos = &cfs->pos;
 114         for (i = 0; i < stream_pos->packet_index->len; i++) {
 115                 index = &g_array_index(stream_pos->packet_index,
 116                                 struct packet_index, i);
 117                 if (index->timestamp_end < timestamp)
 118                         continue;
 119
 120                 stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
 121                 do {
 122                         ret = stream_read_event(cfs);
 123                 } while (cfs->parent.timestamp < timestamp && ret == 0);
 124
 125                 /* Can return either EOF, 0, or error (> 0). */
 126                 return ret;
 127         }
 128         /*
 129          * Cannot find the timestamp within the stream packets, return
 130          * EOF.
 131          */
 132         return EOF;
 133 }
 134
 135 /*
 136  * seek_ctf_trace_by_timestamp : for each file stream, seek to the event with
 137  * the corresponding timestamp
 138  *
 139  * Return 0 on success.
 140  * If the timestamp is not part of any file stream, return EOF to inform the
 141  * user the timestamp is out of the scope.
 142  * On other errors, return positive value.
 143  */
 144 static int seek_ctf_trace_by_timestamp(struct ctf_trace *tin,
 145                 uint64_t timestamp, struct ptr_heap *stream_heap)
 146 {
 147         int i, j, ret;
 148         int found = 0;
 149
 150         /* for each stream_class */
 151         for (i = 0; i < tin->streams->len; i++) {
 152                 struct ctf_stream_declaration *stream_class;
 153
 154                 stream_class = g_ptr_array_index(tin->streams, i);
 155                 if (!stream_class)
 156                         continue;
 157                 /* for each file_stream */
 158                 for (j = 0; j < stream_class->streams->len; j++) {
 159                         struct ctf_stream_definition *stream;
 160                         struct ctf_file_stream *cfs;
 161
 162                         stream = g_ptr_array_index(stream_class->streams, j);
 163                         if (!stream)
 164                                 continue;
 165                         cfs = container_of(stream, struct ctf_file_stream,
 166                                         parent);
 167                         ret = seek_file_stream_by_timestamp(cfs, timestamp);
 168                         if (ret == 0) {
 169                                 /* Add to heap */
 170                                 ret = heap_insert(stream_heap, cfs);
 171                                 if (ret) {
 172                                         /* Return positive error. */
 173                                         return -ret;
 174                                 }
 175                                 found = 1;
 176                         } else if (ret > 0) {
 177                                 /*
 178                                  * Error in seek (not EOF), failure.
 179                                  */
 180                                 return ret;
 181                         }
 182                         /* on EOF just do not put stream into heap. */
 183                 }
 184         }
 185
 186         return found ? 0 : EOF;
 187 }
 188
 189 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *iter_pos)
 190 {
 191         struct trace_collection *tc;
 192         int i, ret;
 193
 194         switch (iter_pos->type) {
 195         case BT_SEEK_RESTORE:
 196                 if (!iter_pos->u.restore)
 197                         return -EINVAL;
 198
 199                 heap_free(iter->stream_heap);
 200                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 201                 if (ret < 0)
 202                         goto error;
 203
 204                 for (i = 0; i < iter_pos->u.restore->stream_saved_pos->len;
 205                                 i++) {
 206                         struct stream_saved_pos *saved_pos;
 207                         struct ctf_stream_pos *stream_pos;
 208                         struct ctf_stream_definition *stream;
 209
 210                         saved_pos = &g_array_index(
 211                                         iter_pos->u.restore->stream_saved_pos,
 212                                         struct stream_saved_pos, i);
 213                         stream = &saved_pos->file_stream->parent;
 214                         stream_pos = &saved_pos->file_stream->pos;
 215
 216                         stream_pos->packet_seek(&stream_pos->parent,
 217                                         saved_pos->cur_index, SEEK_SET);
 218
 219                         /*
 220                          * the timestamp needs to be restored after
 221                          * packet_seek, because this function resets
 222                          * the timestamp to the beginning of the packet
 223                          */
 224                         stream->timestamp = saved_pos->current_timestamp;
 225                         stream_pos->offset = saved_pos->offset;
 226                         stream_pos->last_offset = saved_pos->offset;
 227
 228                         stream->prev_timestamp = 0;
 229                         stream->prev_timestamp_end = 0;
 230                         stream->consumed = 0;
 231
 232                         printf_debug("restored to cur_index = %zd and "
 233                                 "offset = %zd, timestamp = %" PRIu64 "\n",
 234                                 stream_pos->cur_index,
 235                                 stream_pos->offset, stream->timestamp);
 236
 237                         stream_read_event(saved_pos->file_stream);
 238
 239                         /* Add to heap */
 240                         ret = heap_insert(iter->stream_heap,
 241                                         saved_pos->file_stream);
 242                         if (ret)
 243                                 goto error;
 244                 }
 245                 return 0;
 246         case BT_SEEK_TIME:
 247                 tc = iter->ctx->tc;
 248
 249                 heap_free(iter->stream_heap);
 250                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 251                 if (ret < 0)
 252                         goto error;
 253
 254                 /* for each trace in the trace_collection */
 255                 for (i = 0; i < tc->array->len; i++) {
 256                         struct ctf_trace *tin;
 257                         struct trace_descriptor *td_read;
 258
 259                         td_read = g_ptr_array_index(tc->array, i);
 260                         if (!td_read)
 261                                 continue;
 262                         tin = container_of(td_read, struct ctf_trace, parent);
 263
 264                         ret = seek_ctf_trace_by_timestamp(tin,
 265                                         iter_pos->u.seek_time,
 266                                         iter->stream_heap);
 267                         /*
 268                          * Positive errors are failure. Negative value
 269                          * is EOF (for which we continue with other
 270                          * traces). 0 is success. Note: on EOF, it just
 271                          * means that no stream has been added to the
 272                          * iterator for that trace, which is fine.
 273                          */
 274                         if (ret != 0 && ret != EOF)
 275                                 goto error;
 276                 }
 277                 return 0;
 278         case BT_SEEK_BEGIN:
 279                 tc = iter->ctx->tc;
 280                 for (i = 0; i < tc->array->len; i++) {
 281                         struct ctf_trace *tin;
 282                         struct trace_descriptor *td_read;
 283                         int stream_id;
 284
 285                         td_read = g_ptr_array_index(tc->array, i);
 286                         if (!td_read)
 287                                 continue;
 288                         tin = container_of(td_read, struct ctf_trace, parent);
 289
 290                         /* Populate heap with each stream */
 291                         for (stream_id = 0; stream_id < tin->streams->len;
 292                                         stream_id++) {
 293                                 struct ctf_stream_declaration *stream;
 294                                 int filenr;
 295
 296                                 stream = g_ptr_array_index(tin->streams,
 297                                                 stream_id);
 298                                 if (!stream)
 299                                         continue;
 300                                 for (filenr = 0; filenr < stream->streams->len;
 301                                                 filenr++) {
 302                                         struct ctf_file_stream *file_stream;
 303                                         file_stream = g_ptr_array_index(
 304                                                         stream->streams,
 305                                                         filenr);
 306                                         if (!file_stream)
 307                                                 continue;
 308                                         ret = babeltrace_filestream_seek(
 309                                                         file_stream, iter_pos,
 310                                                         stream_id);
 311                                         if (ret != 0 && ret != EOF) {
 312                                                 goto error;
 313                                         }
 314                                 }
 315                         }
 316                 }
 317                 break;
 318         default:
 319                 /* not implemented */
 320                 return -EINVAL;
 321         }
 322
 323         return 0;
 324
 325 error:
 326         heap_free(iter->stream_heap);
 327         if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
 328                 heap_free(iter->stream_heap);
 329                 g_free(iter->stream_heap);
 330                 iter->stream_heap = NULL;
 331                 ret = -ENOMEM;
 332         }
 333         return ret;
 334 }
 335
 336 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
 337 {
 338         struct bt_iter_pos *pos;
 339         struct trace_collection *tc = iter->ctx->tc;
 340         int i, stream_class_id, stream_id;
 341
 342         pos = g_new0(struct bt_iter_pos, 1);
 343         pos->type = BT_SEEK_RESTORE;
 344         pos->u.restore = g_new0(struct bt_saved_pos, 1);
 345         pos->u.restore->tc = tc;
 346         pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
 347                         sizeof(struct stream_saved_pos));
 348         if (!pos->u.restore->stream_saved_pos)
 349                 goto error;
 350
 351         for (i = 0; i < tc->array->len; i++) {
 352                 struct ctf_trace *tin;
 353                 struct trace_descriptor *td_read;
 354
 355                 td_read = g_ptr_array_index(tc->array, i);
 356                 if (!td_read)
 357                         continue;
 358                 tin = container_of(td_read, struct ctf_trace, parent);
 359
 360                 for (stream_class_id = 0; stream_class_id < tin->streams->len;
 361                                 stream_class_id++) {
 362                         struct ctf_stream_declaration *stream_class;
 363
 364                         stream_class = g_ptr_array_index(tin->streams,
 365                                         stream_class_id);
 366                         if (!stream_class)
 367                                 continue;
 368                         for (stream_id = 0;
 369                                         stream_id < stream_class->streams->len;
 370                                         stream_id++) {
 371                                 struct ctf_stream_definition *stream;
 372                                 struct ctf_file_stream *cfs;
 373                                 struct stream_saved_pos saved_pos;
 374
 375                                 stream = g_ptr_array_index(
 376                                                 stream_class->streams,
 377                                                 stream_id);
 378                                 if (!stream)
 379                                         continue;
 380                                 cfs = container_of(stream,
 381                                                 struct ctf_file_stream,
 382                                                 parent);
 383
 384                                 saved_pos.file_stream = cfs;
 385                                 saved_pos.cur_index = cfs->pos.cur_index;
 386
 387                                 /*
 388                                  * It is possible that an event was read during
 389                                  * the last restore, never consumed and its
 390                                  * position saved again.  For this case, we
 391                                  * need to check if the event really was
 392                                  * consumed by the caller otherwise it is lost.
 393                                  */
 394                                 if (stream->consumed)
 395                                         saved_pos.offset = cfs->pos.offset;
 396                                 else
 397                                         saved_pos.offset = cfs->pos.last_offset;
 398
 399                                 saved_pos.current_timestamp = stream->timestamp;
 400
 401                                 g_array_append_val(
 402                                         pos->u.restore->stream_saved_pos,
 403                                         saved_pos);
 404
 405                                 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
 406                                         "offset : %zd, "
 407                                         "timestamp = %" PRIu64 "\n",
 408                                         stream->stream_id, saved_pos.cur_index,
 409                                         saved_pos.offset,
 410                                         saved_pos.current_timestamp);
 411                         }
 412                 }
 413         }
 414
 415         return pos;
 416
 417 error:
 418         return NULL;
 419 }
 420
 421 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 422                 uint64_t timestamp)
 423 {
 424         struct bt_iter_pos *pos;
 425
 426         pos = g_new0(struct bt_iter_pos, 1);
 427         pos->type = BT_SEEK_TIME;
 428         pos->u.seek_time = timestamp;
 429         return pos;
 430 }
 431
 432 /*
 433  * babeltrace_filestream_seek: seek a filestream to given position.
 434  *
 435  * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 436  */
 437 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
 438                 const struct bt_iter_pos *begin_pos,
 439                 unsigned long stream_id)
 440 {
 441         int ret = 0;
 442
 443         switch (begin_pos->type) {
 444         case BT_SEEK_CUR:
 445                 /*
 446                  * just insert into the heap we should already know
 447                  * the timestamps
 448                  */
 449                 break;
 450         case BT_SEEK_BEGIN:
 451                 file_stream->pos.packet_seek(&file_stream->pos.parent,
 452                                 0, SEEK_SET);
 453                 ret = stream_read_event(file_stream);
 454                 break;
 455         case BT_SEEK_TIME:
 456         case BT_SEEK_RESTORE:
 457         case BT_SEEK_END:
 458         default:
 459                 assert(0); /* Not yet defined */
 460         }
 461
 462         return ret;
 463 }
 464
 465 /*
 466  * bt_iter_seek: seek iterator to given position.
 467  */
 468 int bt_iter_seek(struct bt_iter *iter,
 469                 const struct bt_iter_pos *begin_pos)
 470 {
 471         int i, stream_id;
 472         int ret = 0;
 473         struct trace_collection *tc = iter->ctx->tc;
 474
 475         for (i = 0; i < tc->array->len; i++) {
 476                 struct ctf_trace *tin;
 477                 struct trace_descriptor *td_read;
 478
 479                 td_read = g_ptr_array_index(tc->array, i);
 480                 if (!td_read)
 481                         continue;
 482                 tin = container_of(td_read, struct ctf_trace, parent);
 483
 484                 /* Populate heap with each stream */
 485                 for (stream_id = 0; stream_id < tin->streams->len;
 486                                 stream_id++) {
 487                         struct ctf_stream_declaration *stream;
 488                         int filenr;
 489
 490                         stream = g_ptr_array_index(tin->streams, stream_id);
 491                         if (!stream)
 492                                 continue;
 493                         for (filenr = 0; filenr < stream->streams->len;
 494                                         filenr++) {
 495                                 struct ctf_file_stream *file_stream;
 496
 497                                 file_stream = g_ptr_array_index(stream->streams,
 498                                                 filenr);
 499                                 if (!file_stream)
 500                                         continue;
 501                                 ret = babeltrace_filestream_seek(file_stream, begin_pos,
 502                                                 stream_id);
 503                                 if (ret < 0)
 504                                         goto end;
 505                         }
 506                 }
 507         }
 508 end:
 509         return ret;
 510 }
 511
 512 int bt_iter_init(struct bt_iter *iter,
 513                 struct bt_context *ctx,
 514                 const struct bt_iter_pos *begin_pos,
 515                 const struct bt_iter_pos *end_pos)
 516 {
 517         int i, stream_id;
 518         int ret = 0;
 519
 520         if (ctx->current_iterator) {
 521                 ret = -1;
 522                 goto error_ctx;
 523         }
 524
 525         iter->stream_heap = g_new(struct ptr_heap, 1);
 526         iter->end_pos = end_pos;
 527         bt_context_get(ctx);
 528         iter->ctx = ctx;
 529
 530         ret = heap_init(iter->stream_heap, 0, stream_compare);
 531         if (ret < 0)
 532                 goto error_heap_init;
 533
 534         for (i = 0; i < ctx->tc->array->len; i++) {
 535                 struct ctf_trace *tin;
 536                 struct trace_descriptor *td_read;
 537
 538                 td_read = g_ptr_array_index(ctx->tc->array, i);
 539                 if (!td_read)
 540                         continue;
 541                 tin = container_of(td_read, struct ctf_trace, parent);
 542
 543                 /* Populate heap with each stream */
 544                 for (stream_id = 0; stream_id < tin->streams->len;
 545                                 stream_id++) {
 546                         struct ctf_stream_declaration *stream;
 547                         int filenr;
 548
 549                         stream = g_ptr_array_index(tin->streams, stream_id);
 550                         if (!stream)
 551                                 continue;
 552                         for (filenr = 0; filenr < stream->streams->len;
 553                                         filenr++) {
 554                                 struct ctf_file_stream *file_stream;
 555
 556                                 file_stream = g_ptr_array_index(stream->streams,
 557                                                 filenr);
 558                                 if (!file_stream)
 559                                         continue;
 560                                 if (begin_pos) {
 561                                         ret = babeltrace_filestream_seek(
 562                                                         file_stream,
 563                                                         begin_pos,
 564                                                         stream_id);
 565                                 } else {
 566                                         struct bt_iter_pos pos;
 567                                         pos.type = BT_SEEK_BEGIN;
 568                                         ret = babeltrace_filestream_seek(
 569                                                         file_stream, &pos,
 570                                                         stream_id);
 571                                 }
 572                                 if (ret == EOF) {
 573                                         ret = 0;
 574                                         continue;
 575                                 } else if (ret) {
 576                                         goto error;
 577                                 }
 578                                 /* Add to heap */
 579                                 ret = heap_insert(iter->stream_heap, file_stream);
 580                                 if (ret)
 581                                         goto error;
 582                         }
 583                 }
 584         }
 585
 586         ctx->current_iterator = iter;
 587         return 0;
 588
 589 error:
 590         heap_free(iter->stream_heap);
 591 error_heap_init:
 592         g_free(iter->stream_heap);
 593 error_ctx:
 594         return ret;
 595 }
 596
 597 struct bt_iter *bt_iter_create(struct bt_context *ctx,
 598                 const struct bt_iter_pos *begin_pos,
 599                 const struct bt_iter_pos *end_pos)
 600 {
 601         struct bt_iter *iter;
 602         int ret;
 603
 604         iter = g_new0(struct bt_iter, 1);
 605         ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
 606         if (ret) {
 607                 g_free(iter);
 608                 return NULL;
 609         }
 610         return iter;
 611 }
 612
 613 void bt_iter_fini(struct bt_iter *iter)
 614 {
 615         if (iter->stream_heap) {
 616                 heap_free(iter->stream_heap);
 617                 g_free(iter->stream_heap);
 618         }
 619         iter->ctx->current_iterator = NULL;
 620         bt_context_put(iter->ctx);
 621 }
 622
 623 void bt_iter_destroy(struct bt_iter *iter)
 624 {
 625         bt_iter_fini(iter);
 626         g_free(iter);
 627 }
 628
 629 int bt_iter_next(struct bt_iter *iter)
 630 {
 631         struct ctf_file_stream *file_stream, *removed;
 632         int ret;
 633
 634         file_stream = heap_maximum(iter->stream_heap);
 635         if (!file_stream) {
 636                 /* end of file for all streams */
 637                 ret = 0;
 638                 goto end;
 639         }
 640
 641         ret = stream_read_event(file_stream);
 642         if (ret == EOF) {
 643                 removed = heap_remove(iter->stream_heap);
 644                 assert(removed == file_stream);
 645                 ret = 0;
 646                 goto end;
 647         } else if (ret) {
 648                 goto end;
 649         }
 650         /* Reinsert the file stream into the heap, and rebalance. */
 651         removed = heap_replace_max(iter->stream_heap, file_stream);
 652         assert(removed == file_stream);
 653
 654 end:
 655         return ret;
 656 }