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_heap_init;
 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 = LAST_OFFSET_POISON;
 227
 228                         stream->prev_timestamp = 0;
 229                         stream->prev_timestamp_end = 0;
 230
 231                         printf_debug("restored to cur_index = %zd and "
 232                                 "offset = %zd, timestamp = %" PRIu64 "\n",
 233                                 stream_pos->cur_index,
 234                                 stream_pos->offset, stream->timestamp);
 235
 236                         stream_read_event(saved_pos->file_stream);
 237
 238                         /* Add to heap */
 239                         ret = heap_insert(iter->stream_heap,
 240                                         saved_pos->file_stream);
 241                         if (ret)
 242                                 goto error;
 243                 }
 244                 return 0;
 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_heap_init;
 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                 heap_free(iter->stream_heap);
 280                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 281                 if (ret < 0)
 282                         goto error_heap_init;
 283
 284                 for (i = 0; i < tc->array->len; i++) {
 285                         struct ctf_trace *tin;
 286                         struct trace_descriptor *td_read;
 287                         int stream_id;
 288
 289                         td_read = g_ptr_array_index(tc->array, i);
 290                         if (!td_read)
 291                                 continue;
 292                         tin = container_of(td_read, struct ctf_trace, parent);
 293
 294                         /* Populate heap with each stream */
 295                         for (stream_id = 0; stream_id < tin->streams->len;
 296                                         stream_id++) {
 297                                 struct ctf_stream_declaration *stream;
 298                                 int filenr;
 299
 300                                 stream = g_ptr_array_index(tin->streams,
 301                                                 stream_id);
 302                                 if (!stream)
 303                                         continue;
 304                                 for (filenr = 0; filenr < stream->streams->len;
 305                                                 filenr++) {
 306                                         struct ctf_file_stream *file_stream;
 307                                         file_stream = g_ptr_array_index(
 308                                                         stream->streams,
 309                                                         filenr);
 310                                         if (!file_stream)
 311                                                 continue;
 312                                         ret = babeltrace_filestream_seek(
 313                                                         file_stream, iter_pos,
 314                                                         stream_id);
 315                                         if (ret != 0 && ret != EOF) {
 316                                                 goto error;
 317                                         }
 318                                         ret = heap_insert(iter->stream_heap, file_stream);
 319                                         if (ret)
 320                                                 goto error;
 321                                 }
 322                         }
 323                 }
 324                 break;
 325         default:
 326                 /* not implemented */
 327                 return -EINVAL;
 328         }
 329
 330         return 0;
 331
 332 error:
 333         heap_free(iter->stream_heap);
 334 error_heap_init:
 335         if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
 336                 heap_free(iter->stream_heap);
 337                 g_free(iter->stream_heap);
 338                 iter->stream_heap = NULL;
 339                 ret = -ENOMEM;
 340         }
 341
 342         return ret;
 343 }
 344
 345 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
 346 {
 347         struct bt_iter_pos *pos;
 348         struct trace_collection *tc = iter->ctx->tc;
 349         struct ctf_file_stream *file_stream = NULL, *removed;
 350         struct ptr_heap iter_heap_copy;
 351         int ret;
 352
 353         pos = g_new0(struct bt_iter_pos, 1);
 354         pos->type = BT_SEEK_RESTORE;
 355         pos->u.restore = g_new0(struct bt_saved_pos, 1);
 356         pos->u.restore->tc = tc;
 357         pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
 358                         sizeof(struct stream_saved_pos));
 359         if (!pos->u.restore->stream_saved_pos)
 360                 goto error;
 361
 362         ret = heap_copy(&iter_heap_copy, iter->stream_heap);
 363         if (ret < 0)
 364                 goto error_heap;
 365
 366         /* iterate over each stream in the heap */
 367         file_stream = heap_maximum(&iter_heap_copy);
 368         while (file_stream != NULL) {
 369                 struct stream_saved_pos saved_pos;
 370
 371                 assert(file_stream->pos.last_offset != LAST_OFFSET_POISON);
 372                 saved_pos.offset = file_stream->pos.last_offset;
 373                 saved_pos.file_stream = file_stream;
 374                 saved_pos.cur_index = file_stream->pos.cur_index;
 375
 376                 saved_pos.current_timestamp = file_stream->parent.timestamp;
 377
 378                 g_array_append_val(
 379                                 pos->u.restore->stream_saved_pos,
 380                                 saved_pos);
 381
 382                 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
 383                                 "offset : %zd, "
 384                                 "timestamp = %" PRIu64 "\n",
 385                                 file_stream->parent.stream_id,
 386                                 saved_pos.cur_index, saved_pos.offset,
 387                                 saved_pos.current_timestamp);
 388
 389                 /* remove the stream from the heap copy */
 390                 removed = heap_remove(&iter_heap_copy);
 391                 assert(removed == file_stream);
 392
 393                 file_stream = heap_maximum(&iter_heap_copy);
 394         }
 395         heap_free(&iter_heap_copy);
 396         return pos;
 397
 398 error_heap:
 399         g_array_free(pos->u.restore->stream_saved_pos, TRUE);
 400 error:
 401         g_free(pos);
 402         return NULL;
 403 }
 404
 405 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 406                 uint64_t timestamp)
 407 {
 408         struct bt_iter_pos *pos;
 409
 410         pos = g_new0(struct bt_iter_pos, 1);
 411         pos->type = BT_SEEK_TIME;
 412         pos->u.seek_time = timestamp;
 413         return pos;
 414 }
 415
 416 /*
 417  * babeltrace_filestream_seek: seek a filestream to given position.
 418  *
 419  * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 420  */
 421 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
 422                 const struct bt_iter_pos *begin_pos,
 423                 unsigned long stream_id)
 424 {
 425         int ret = 0;
 426
 427         switch (begin_pos->type) {
 428         case BT_SEEK_CUR:
 429                 /*
 430                  * just insert into the heap we should already know
 431                  * the timestamps
 432                  */
 433                 break;
 434         case BT_SEEK_BEGIN:
 435                 file_stream->pos.packet_seek(&file_stream->pos.parent,
 436                                 0, SEEK_SET);
 437                 ret = stream_read_event(file_stream);
 438                 break;
 439         case BT_SEEK_TIME:
 440         case BT_SEEK_RESTORE:
 441         case BT_SEEK_END:
 442         default:
 443                 assert(0); /* Not yet defined */
 444         }
 445
 446         return ret;
 447 }
 448
 449 int bt_iter_init(struct bt_iter *iter,
 450                 struct bt_context *ctx,
 451                 const struct bt_iter_pos *begin_pos,
 452                 const struct bt_iter_pos *end_pos)
 453 {
 454         int i, stream_id;
 455         int ret = 0;
 456
 457         if (ctx->current_iterator) {
 458                 ret = -1;
 459                 goto error_ctx;
 460         }
 461
 462         iter->stream_heap = g_new(struct ptr_heap, 1);
 463         iter->end_pos = end_pos;
 464         bt_context_get(ctx);
 465         iter->ctx = ctx;
 466
 467         ret = heap_init(iter->stream_heap, 0, stream_compare);
 468         if (ret < 0)
 469                 goto error_heap_init;
 470
 471         for (i = 0; i < ctx->tc->array->len; i++) {
 472                 struct ctf_trace *tin;
 473                 struct trace_descriptor *td_read;
 474
 475                 td_read = g_ptr_array_index(ctx->tc->array, i);
 476                 if (!td_read)
 477                         continue;
 478                 tin = container_of(td_read, struct ctf_trace, parent);
 479
 480                 /* Populate heap with each stream */
 481                 for (stream_id = 0; stream_id < tin->streams->len;
 482                                 stream_id++) {
 483                         struct ctf_stream_declaration *stream;
 484                         int filenr;
 485
 486                         stream = g_ptr_array_index(tin->streams, stream_id);
 487                         if (!stream)
 488                                 continue;
 489                         for (filenr = 0; filenr < stream->streams->len;
 490                                         filenr++) {
 491                                 struct ctf_file_stream *file_stream;
 492
 493                                 file_stream = g_ptr_array_index(stream->streams,
 494                                                 filenr);
 495                                 if (!file_stream)
 496                                         continue;
 497                                 if (begin_pos) {
 498                                         ret = babeltrace_filestream_seek(
 499                                                         file_stream,
 500                                                         begin_pos,
 501                                                         stream_id);
 502                                 } else {
 503                                         struct bt_iter_pos pos;
 504                                         pos.type = BT_SEEK_BEGIN;
 505                                         ret = babeltrace_filestream_seek(
 506                                                         file_stream, &pos,
 507                                                         stream_id);
 508                                 }
 509                                 if (ret == EOF) {
 510                                         ret = 0;
 511                                         continue;
 512                                 } else if (ret) {
 513                                         goto error;
 514                                 }
 515                                 /* Add to heap */
 516                                 ret = heap_insert(iter->stream_heap, file_stream);
 517                                 if (ret)
 518                                         goto error;
 519                         }
 520                 }
 521         }
 522
 523         ctx->current_iterator = iter;
 524         return 0;
 525
 526 error:
 527         heap_free(iter->stream_heap);
 528 error_heap_init:
 529         g_free(iter->stream_heap);
 530         iter->stream_heap = NULL;
 531 error_ctx:
 532         return ret;
 533 }
 534
 535 struct bt_iter *bt_iter_create(struct bt_context *ctx,
 536                 const struct bt_iter_pos *begin_pos,
 537                 const struct bt_iter_pos *end_pos)
 538 {
 539         struct bt_iter *iter;
 540         int ret;
 541
 542         iter = g_new0(struct bt_iter, 1);
 543         ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
 544         if (ret) {
 545                 g_free(iter);
 546                 return NULL;
 547         }
 548         return iter;
 549 }
 550
 551 void bt_iter_fini(struct bt_iter *iter)
 552 {
 553         if (iter->stream_heap) {
 554                 heap_free(iter->stream_heap);
 555                 g_free(iter->stream_heap);
 556         }
 557         iter->ctx->current_iterator = NULL;
 558         bt_context_put(iter->ctx);
 559 }
 560
 561 void bt_iter_destroy(struct bt_iter *iter)
 562 {
 563         bt_iter_fini(iter);
 564         g_free(iter);
 565 }
 566
 567 int bt_iter_next(struct bt_iter *iter)
 568 {
 569         struct ctf_file_stream *file_stream, *removed;
 570         int ret;
 571
 572         file_stream = heap_maximum(iter->stream_heap);
 573         if (!file_stream) {
 574                 /* end of file for all streams */
 575                 ret = 0;
 576                 goto end;
 577         }
 578
 579         ret = stream_read_event(file_stream);
 580         if (ret == EOF) {
 581                 removed = heap_remove(iter->stream_heap);
 582                 assert(removed == file_stream);
 583                 ret = 0;
 584                 goto end;
 585         } else if (ret) {
 586                 goto end;
 587         }
 588         /* Reinsert the file stream into the heap, and rebalance. */
 589         removed = heap_replace_max(iter->stream_heap, file_stream);
 590         assert(removed == file_stream);
 591
 592 end:
 593         return ret;
 594 }