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->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         case BT_SEEK_TIME:
 246                 tc = iter->ctx->tc;
 247
 248                 heap_free(iter->stream_heap);
 249                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 250                 if (ret < 0)
 251                         goto error;
 252
 253                 /* for each trace in the trace_collection */
 254                 for (i = 0; i < tc->array->len; i++) {
 255                         struct ctf_trace *tin;
 256                         struct trace_descriptor *td_read;
 257
 258                         td_read = g_ptr_array_index(tc->array, i);
 259                         if (!td_read)
 260                                 continue;
 261                         tin = container_of(td_read, struct ctf_trace, parent);
 262
 263                         ret = seek_ctf_trace_by_timestamp(tin,
 264                                         iter_pos->u.seek_time,
 265                                         iter->stream_heap);
 266                         /*
 267                          * Positive errors are failure. Negative value
 268                          * is EOF (for which we continue with other
 269                          * traces). 0 is success. Note: on EOF, it just
 270                          * means that no stream has been added to the
 271                          * iterator for that trace, which is fine.
 272                          */
 273                         if (ret != 0 && ret != EOF)
 274                                 goto error;
 275                 }
 276                 return 0;
 277         case BT_SEEK_BEGIN:
 278                 tc = iter->ctx->tc;
 279                 for (i = 0; i < tc->array->len; i++) {
 280                         struct ctf_trace *tin;
 281                         struct trace_descriptor *td_read;
 282                         int stream_id;
 283
 284                         td_read = g_ptr_array_index(tc->array, i);
 285                         if (!td_read)
 286                                 continue;
 287                         tin = container_of(td_read, struct ctf_trace, parent);
 288
 289                         /* Populate heap with each stream */
 290                         for (stream_id = 0; stream_id < tin->streams->len;
 291                                         stream_id++) {
 292                                 struct ctf_stream_declaration *stream;
 293                                 int filenr;
 294
 295                                 stream = g_ptr_array_index(tin->streams,
 296                                                 stream_id);
 297                                 if (!stream)
 298                                         continue;
 299                                 for (filenr = 0; filenr < stream->streams->len;
 300                                                 filenr++) {
 301                                         struct ctf_file_stream *file_stream;
 302                                         file_stream = g_ptr_array_index(
 303                                                         stream->streams,
 304                                                         filenr);
 305                                         if (!file_stream)
 306                                                 continue;
 307                                         ret = babeltrace_filestream_seek(
 308                                                         file_stream, iter_pos,
 309                                                         stream_id);
 310                                         if (ret != 0 && ret != EOF) {
 311                                                 goto error;
 312                                         }
 313                                 }
 314                         }
 315                 }
 316                 break;
 317         default:
 318                 /* not implemented */
 319                 return -EINVAL;
 320         }
 321
 322         return 0;
 323
 324 error:
 325         heap_free(iter->stream_heap);
 326         if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
 327                 heap_free(iter->stream_heap);
 328                 g_free(iter->stream_heap);
 329                 iter->stream_heap = NULL;
 330                 ret = -ENOMEM;
 331         }
 332         return ret;
 333 }
 334
 335 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
 336 {
 337         struct bt_iter_pos *pos;
 338         struct trace_collection *tc = iter->ctx->tc;
 339         int i, stream_class_id, stream_id;
 340
 341         pos = g_new0(struct bt_iter_pos, 1);
 342         pos->u.restore = g_new0(struct bt_saved_pos, 1);
 343         pos->u.restore->tc = tc;
 344         pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
 345                         sizeof(struct stream_saved_pos));
 346         if (!pos->u.restore->stream_saved_pos)
 347                 goto error;
 348
 349         for (i = 0; i < tc->array->len; i++) {
 350                 struct ctf_trace *tin;
 351                 struct trace_descriptor *td_read;
 352
 353                 td_read = g_ptr_array_index(tc->array, i);
 354                 if (!td_read)
 355                         continue;
 356                 tin = container_of(td_read, struct ctf_trace, parent);
 357
 358                 for (stream_class_id = 0; stream_class_id < tin->streams->len;
 359                                 stream_class_id++) {
 360                         struct ctf_stream_declaration *stream_class;
 361
 362                         stream_class = g_ptr_array_index(tin->streams,
 363                                         stream_class_id);
 364                         if (!stream_class)
 365                                 continue;
 366                         for (stream_id = 0;
 367                                         stream_id < stream_class->streams->len;
 368                                         stream_id++) {
 369                                 struct ctf_stream_definition *stream;
 370                                 struct ctf_file_stream *cfs;
 371                                 struct stream_saved_pos saved_pos;
 372
 373                                 stream = g_ptr_array_index(
 374                                                 stream_class->streams,
 375                                                 stream_id);
 376                                 if (!stream)
 377                                         continue;
 378                                 cfs = container_of(stream,
 379                                                 struct ctf_file_stream,
 380                                                 parent);
 381
 382                                 saved_pos.file_stream = cfs;
 383                                 saved_pos.cur_index = cfs->pos.cur_index;
 384
 385                                 /*
 386                                  * It is possible that an event was read during
 387                                  * the last restore, never consumed and its
 388                                  * position saved again.  For this case, we
 389                                  * need to check if the event really was
 390                                  * consumed by the caller otherwise it is lost.
 391                                  */
 392                                 if (stream->consumed)
 393                                         saved_pos.offset = cfs->pos.offset;
 394                                 else
 395                                         saved_pos.offset = cfs->pos.last_offset;
 396
 397                                 saved_pos.current_timestamp = stream->timestamp;
 398
 399                                 g_array_append_val(
 400                                         pos->u.restore->stream_saved_pos,
 401                                         saved_pos);
 402
 403                                 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
 404                                         "offset : %zd, "
 405                                         "timestamp = %" PRIu64 "\n",
 406                                         stream->stream_id, saved_pos.cur_index,
 407                                         saved_pos.offset,
 408                                         saved_pos.current_timestamp);
 409                         }
 410                 }
 411         }
 412
 413         return pos;
 414
 415 error:
 416         return NULL;
 417 }
 418
 419 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 420                 uint64_t timestamp)
 421 {
 422         struct bt_iter_pos *pos;
 423
 424         pos = g_new0(struct bt_iter_pos, 1);
 425         pos->type = BT_SEEK_TIME;
 426         pos->u.seek_time = timestamp;
 427         return pos;
 428 }
 429
 430 /*
 431  * babeltrace_filestream_seek: seek a filestream to given position.
 432  *
 433  * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 434  */
 435 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
 436                 const struct bt_iter_pos *begin_pos,
 437                 unsigned long stream_id)
 438 {
 439         int ret = 0;
 440
 441         switch (begin_pos->type) {
 442         case BT_SEEK_CUR:
 443                 /*
 444                  * just insert into the heap we should already know
 445                  * the timestamps
 446                  */
 447                 break;
 448         case BT_SEEK_BEGIN:
 449                 file_stream->pos.packet_seek(&file_stream->pos.parent,
 450                                 0, SEEK_SET);
 451                 ret = stream_read_event(file_stream);
 452                 break;
 453         case BT_SEEK_TIME:
 454         case BT_SEEK_RESTORE:
 455         case BT_SEEK_END:
 456         default:
 457                 assert(0); /* Not yet defined */
 458         }
 459
 460         return ret;
 461 }
 462
 463 /*
 464  * bt_iter_seek: seek iterator to given position.
 465  */
 466 int bt_iter_seek(struct bt_iter *iter,
 467                 const struct bt_iter_pos *begin_pos)
 468 {
 469         int i, stream_id;
 470         int ret = 0;
 471         struct trace_collection *tc = iter->ctx->tc;
 472
 473         for (i = 0; i < tc->array->len; i++) {
 474                 struct ctf_trace *tin;
 475                 struct trace_descriptor *td_read;
 476
 477                 td_read = g_ptr_array_index(tc->array, i);
 478                 if (!td_read)
 479                         continue;
 480                 tin = container_of(td_read, struct ctf_trace, parent);
 481
 482                 /* Populate heap with each stream */
 483                 for (stream_id = 0; stream_id < tin->streams->len;
 484                                 stream_id++) {
 485                         struct ctf_stream_declaration *stream;
 486                         int filenr;
 487
 488                         stream = g_ptr_array_index(tin->streams, stream_id);
 489                         if (!stream)
 490                                 continue;
 491                         for (filenr = 0; filenr < stream->streams->len;
 492                                         filenr++) {
 493                                 struct ctf_file_stream *file_stream;
 494
 495                                 file_stream = g_ptr_array_index(stream->streams,
 496                                                 filenr);
 497                                 if (!file_stream)
 498                                         continue;
 499                                 ret = babeltrace_filestream_seek(file_stream, begin_pos,
 500                                                 stream_id);
 501                                 if (ret < 0)
 502                                         goto end;
 503                         }
 504                 }
 505         }
 506 end:
 507         return ret;
 508 }
 509
 510 int bt_iter_init(struct bt_iter *iter,
 511                 struct bt_context *ctx,
 512                 const struct bt_iter_pos *begin_pos,
 513                 const struct bt_iter_pos *end_pos)
 514 {
 515         int i, stream_id;
 516         int ret = 0;
 517
 518         if (ctx->current_iterator) {
 519                 ret = -1;
 520                 goto error_ctx;
 521         }
 522
 523         iter->stream_heap = g_new(struct ptr_heap, 1);
 524         iter->end_pos = end_pos;
 525         bt_context_get(ctx);
 526         iter->ctx = ctx;
 527
 528         ret = heap_init(iter->stream_heap, 0, stream_compare);
 529         if (ret < 0)
 530                 goto error_heap_init;
 531
 532         for (i = 0; i < ctx->tc->array->len; i++) {
 533                 struct ctf_trace *tin;
 534                 struct trace_descriptor *td_read;
 535
 536                 td_read = g_ptr_array_index(ctx->tc->array, i);
 537                 if (!td_read)
 538                         continue;
 539                 tin = container_of(td_read, struct ctf_trace, parent);
 540
 541                 /* Populate heap with each stream */
 542                 for (stream_id = 0; stream_id < tin->streams->len;
 543                                 stream_id++) {
 544                         struct ctf_stream_declaration *stream;
 545                         int filenr;
 546
 547                         stream = g_ptr_array_index(tin->streams, stream_id);
 548                         if (!stream)
 549                                 continue;
 550                         for (filenr = 0; filenr < stream->streams->len;
 551                                         filenr++) {
 552                                 struct ctf_file_stream *file_stream;
 553
 554                                 file_stream = g_ptr_array_index(stream->streams,
 555                                                 filenr);
 556                                 if (!file_stream)
 557                                         continue;
 558                                 if (begin_pos) {
 559                                         ret = babeltrace_filestream_seek(
 560                                                         file_stream,
 561                                                         begin_pos,
 562                                                         stream_id);
 563                                 } else {
 564                                         struct bt_iter_pos pos;
 565                                         pos.type = BT_SEEK_BEGIN;
 566                                         ret = babeltrace_filestream_seek(
 567                                                         file_stream, &pos,
 568                                                         stream_id);
 569                                 }
 570                                 if (ret == EOF) {
 571                                         ret = 0;
 572                                         continue;
 573                                 } else if (ret) {
 574                                         goto error;
 575                                 }
 576                                 /* Add to heap */
 577                                 ret = heap_insert(iter->stream_heap, file_stream);
 578                                 if (ret)
 579                                         goto error;
 580                         }
 581                 }
 582         }
 583
 584         ctx->current_iterator = iter;
 585         return 0;
 586
 587 error:
 588         heap_free(iter->stream_heap);
 589 error_heap_init:
 590         g_free(iter->stream_heap);
 591 error_ctx:
 592         return ret;
 593 }
 594
 595 struct bt_iter *bt_iter_create(struct bt_context *ctx,
 596                 const struct bt_iter_pos *begin_pos,
 597                 const struct bt_iter_pos *end_pos)
 598 {
 599         struct bt_iter *iter;
 600         int ret;
 601
 602         iter = g_new0(struct bt_iter, 1);
 603         ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
 604         if (ret) {
 605                 g_free(iter);
 606                 return NULL;
 607         }
 608         return iter;
 609 }
 610
 611 void bt_iter_fini(struct bt_iter *iter)
 612 {
 613         if (iter->stream_heap) {
 614                 heap_free(iter->stream_heap);
 615                 g_free(iter->stream_heap);
 616         }
 617         iter->ctx->current_iterator = NULL;
 618         bt_context_put(iter->ctx);
 619 }
 620
 621 void bt_iter_destroy(struct bt_iter *iter)
 622 {
 623         bt_iter_fini(iter);
 624         g_free(iter);
 625 }
 626
 627 int bt_iter_next(struct bt_iter *iter)
 628 {
 629         struct ctf_file_stream *file_stream, *removed;
 630         int ret;
 631
 632         file_stream = heap_maximum(iter->stream_heap);
 633         if (!file_stream) {
 634                 /* end of file for all streams */
 635                 ret = 0;
 636                 goto end;
 637         }
 638
 639         ret = stream_read_event(file_stream);
 640         if (ret == EOF) {
 641                 removed = heap_remove(iter->stream_heap);
 642                 assert(removed == file_stream);
 643                 ret = 0;
 644                 goto end;
 645         } else if (ret) {
 646                 goto end;
 647         }
 648         /* Reinsert the file stream into the heap, and rebalance. */
 649         removed = heap_replace_max(iter->stream_heap, file_stream);
 650         assert(removed == file_stream);
 651
 652 end:
 653         return ret;
 654 }