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 struct stream_saved_pos {
  33         /*
  34          * Use file_stream pointer to check if the trace collection we
  35          * restore to match the one we saved from, for each stream.
  36          */
  37         struct ctf_file_stream *file_stream;
  38         size_t cur_index;       /* current index in packet index */
  39         ssize_t offset;         /* offset from base, in bits. EOF for end of file. */
  40         uint64_t current_timestamp;
  41 };
  42
  43 struct bt_saved_pos {
  44         struct trace_collection *tc;
  45         GArray *stream_saved_pos;       /* Contains struct stream_saved_pos */
  46 };
  47
  48 static int stream_read_event(struct ctf_file_stream *sin)
  49 {
  50         int ret;
  51
  52         ret = sin->pos.parent.event_cb(&sin->pos.parent, &sin->parent);
  53         if (ret == EOF)
  54                 return EOF;
  55         else if (ret) {
  56                 fprintf(stderr, "[error] Reading event failed.\n");
  57                 return ret;
  58         }
  59         return 0;
  60 }
  61
  62 /*
  63  * returns true if a < b, false otherwise.
  64  */
  65 int stream_compare(void *a, void *b)
  66 {
  67         struct ctf_file_stream *s_a = a, *s_b = b;
  68
  69         if (s_a->parent.timestamp < s_b->parent.timestamp)
  70                 return 1;
  71         else
  72                 return 0;
  73 }
  74
  75 void bt_iter_free_pos(struct bt_iter_pos *iter_pos)
  76 {
  77         if (!iter_pos)
  78                 return;
  79
  80         if (iter_pos->u.restore) {
  81                 if (iter_pos->u.restore->stream_saved_pos) {
  82                         g_array_free(
  83                                 iter_pos->u.restore->stream_saved_pos,
  84                                 TRUE);
  85                 }
  86                 g_free(iter_pos->u.restore);
  87         }
  88         g_free(iter_pos);
  89 }
  90
  91 /*
  92  * seek_file_stream_by_timestamp
  93  *
  94  * Browse a filestream by index, if an index contains the timestamp passed in
  95  * argument, seek inside the corresponding packet it until we find the event we
  96  * are looking for (either the exact timestamp or the event just after the
  97  * timestamp).
  98  *
  99  * Return 0 if the seek succeded and EOF if we didn't find any packet
 100  * containing the timestamp.
 101  */
 102 static int seek_file_stream_by_timestamp(struct ctf_file_stream *cfs,
 103                 uint64_t timestamp)
 104 {
 105         struct ctf_stream_pos *stream_pos;
 106         struct packet_index *index;
 107         int i, ret;
 108
 109         stream_pos = &cfs->pos;
 110         for (i = 0; i < stream_pos->packet_index->len; i++) {
 111                 index = &g_array_index(stream_pos->packet_index,
 112                                 struct packet_index, i);
 113                 if (index->timestamp_end <= timestamp)
 114                         continue;
 115
 116                 stream_pos->packet_seek(&stream_pos->parent, i, SEEK_SET);
 117                 while (cfs->parent.timestamp < timestamp) {
 118                         ret = stream_read_event(cfs);
 119                         if (ret < 0)
 120                                 break;
 121                 }
 122                 return 0;
 123         }
 124         return EOF;
 125 }
 126
 127 /*
 128  * seek_ctf_trace_by_timestamp : for each file stream, seek to the event with
 129  * the corresponding timestamp
 130  *
 131  * Return 0 on success.
 132  * If the timestamp is not part of any file stream, return EOF to inform the
 133  * user the timestamp is out of the scope
 134  */
 135 static int seek_ctf_trace_by_timestamp(struct ctf_trace *tin,
 136                 uint64_t timestamp, struct ptr_heap *stream_heap)
 137 {
 138         int i, j, ret;
 139         int found = EOF;
 140
 141         /* for each stream_class */
 142         for (i = 0; i < tin->streams->len; i++) {
 143                 struct ctf_stream_class *stream_class;
 144
 145                 stream_class = g_ptr_array_index(tin->streams, i);
 146                 /* for each file_stream */
 147                 for (j = 0; j < stream_class->streams->len; j++) {
 148                         struct ctf_stream *stream;
 149                         struct ctf_file_stream *cfs;
 150
 151                         stream = g_ptr_array_index(stream_class->streams, j);
 152                         cfs = container_of(stream, struct ctf_file_stream,
 153                                         parent);
 154                         ret = seek_file_stream_by_timestamp(cfs, timestamp);
 155                         if (ret == 0) {
 156                                 /* Add to heap */
 157                                 ret = heap_insert(stream_heap, cfs);
 158                                 if (ret)
 159                                         goto error;
 160                                 found = 0;
 161                         }
 162                 }
 163         }
 164
 165         return found;
 166
 167 error:
 168         return -2;
 169 }
 170
 171 int bt_iter_set_pos(struct bt_iter *iter, const struct bt_iter_pos *iter_pos)
 172 {
 173         struct trace_collection *tc;
 174         int i, ret;
 175
 176         switch (iter_pos->type) {
 177         case BT_SEEK_RESTORE:
 178                 if (!iter_pos->u.restore)
 179                         return -EINVAL;
 180
 181                 heap_free(iter->stream_heap);
 182                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 183                 if (ret < 0)
 184                         goto error;
 185
 186                 for (i = 0; i < iter_pos->u.restore->stream_saved_pos->len;
 187                                 i++) {
 188                         struct stream_saved_pos *saved_pos;
 189                         struct ctf_stream_pos *stream_pos;
 190                         struct ctf_stream *stream;
 191
 192                         saved_pos = &g_array_index(
 193                                         iter_pos->u.restore->stream_saved_pos,
 194                                         struct stream_saved_pos, i);
 195                         stream = &saved_pos->file_stream->parent;
 196                         stream_pos = &saved_pos->file_stream->pos;
 197
 198                         stream_pos->packet_seek(&stream_pos->parent,
 199                                         saved_pos->cur_index, SEEK_SET);
 200
 201                         /*
 202                          * the timestamp needs to be restored after
 203                          * packet_seek, because this function resets
 204                          * the timestamp to the beginning of the packet
 205                          */
 206                         stream->timestamp = saved_pos->current_timestamp;
 207                         stream_pos->offset = saved_pos->offset;
 208                         stream_pos->last_offset = saved_pos->offset;
 209
 210                         stream->prev_timestamp = 0;
 211                         stream->prev_timestamp_end = 0;
 212                         stream->consumed = 0;
 213
 214                         printf_debug("restored to cur_index = %zd and "
 215                                 "offset = %zd, timestamp = %" PRIu64 "\n",
 216                                 stream_pos->cur_index,
 217                                 stream_pos->offset, stream->timestamp);
 218
 219                         stream_read_event(saved_pos->file_stream);
 220
 221                         /* Add to heap */
 222                         ret = heap_insert(iter->stream_heap,
 223                                         saved_pos->file_stream);
 224                         if (ret)
 225                                 goto error;
 226                 }
 227         case BT_SEEK_TIME:
 228                 tc = iter->ctx->tc;
 229
 230                 heap_free(iter->stream_heap);
 231                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 232                 if (ret < 0)
 233                         goto error;
 234
 235                 /* for each trace in the trace_collection */
 236                 for (i = 0; i < tc->array->len; i++) {
 237                         struct ctf_trace *tin;
 238                         struct trace_descriptor *td_read;
 239
 240                         td_read = g_ptr_array_index(tc->array, i);
 241                         tin = container_of(td_read, struct ctf_trace, parent);
 242
 243                         ret = seek_ctf_trace_by_timestamp(tin,
 244                                         iter_pos->u.seek_time,
 245                                         iter->stream_heap);
 246                         if (ret < 0)
 247                                 goto error;
 248                 }
 249                 return 0;
 250         default:
 251                 /* not implemented */
 252                 return -EINVAL;
 253         }
 254
 255         return 0;
 256
 257 error:
 258         heap_free(iter->stream_heap);
 259         if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
 260                 heap_free(iter->stream_heap);
 261                 g_free(iter->stream_heap);
 262                 iter->stream_heap = NULL;
 263                 ret = -ENOMEM;
 264         }
 265         return ret;
 266 }
 267
 268 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
 269 {
 270         struct bt_iter_pos *pos;
 271         struct trace_collection *tc = iter->ctx->tc;
 272         int i, stream_class_id, stream_id;
 273
 274         pos = g_new0(struct bt_iter_pos, 1);
 275         pos->u.restore = g_new0(struct bt_saved_pos, 1);
 276         pos->u.restore->tc = tc;
 277         pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
 278                         sizeof(struct stream_saved_pos));
 279         if (!pos->u.restore->stream_saved_pos)
 280                 goto error;
 281
 282         for (i = 0; i < tc->array->len; i++) {
 283                 struct ctf_trace *tin;
 284                 struct trace_descriptor *td_read;
 285
 286                 td_read = g_ptr_array_index(tc->array, i);
 287                 tin = container_of(td_read, struct ctf_trace, parent);
 288
 289                 for (stream_class_id = 0; stream_class_id < tin->streams->len;
 290                                 stream_class_id++) {
 291                         struct ctf_stream_class *stream_class;
 292
 293                         stream_class = g_ptr_array_index(tin->streams,
 294                                         stream_class_id);
 295                         for (stream_id = 0;
 296                                         stream_id < stream_class->streams->len;
 297                                         stream_id++) {
 298                                 struct ctf_stream *stream;
 299                                 struct ctf_file_stream *cfs;
 300                                 struct stream_saved_pos saved_pos;
 301
 302                                 stream = g_ptr_array_index(
 303                                                 stream_class->streams,
 304                                                 stream_id);
 305                                 cfs = container_of(stream,
 306                                                 struct ctf_file_stream,
 307                                                 parent);
 308
 309                                 saved_pos.file_stream = cfs;
 310                                 saved_pos.cur_index = cfs->pos.cur_index;
 311
 312                                 /*
 313                                  * It is possible that an event was read during
 314                                  * the last restore, never consumed and its
 315                                  * position saved again.  For this case, we
 316                                  * need to check if the event really was
 317                                  * consumed by the caller otherwise it is lost.
 318                                  */
 319                                 if (stream->consumed)
 320                                         saved_pos.offset = cfs->pos.offset;
 321                                 else
 322                                         saved_pos.offset = cfs->pos.last_offset;
 323
 324                                 saved_pos.current_timestamp = stream->timestamp;
 325
 326                                 g_array_append_val(
 327                                         pos->u.restore->stream_saved_pos,
 328                                         saved_pos);
 329
 330                                 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
 331                                         "offset : %zd, "
 332                                         "timestamp = %" PRIu64 "\n",
 333                                         stream->stream_id, saved_pos.cur_index,
 334                                         saved_pos.offset,
 335                                         saved_pos.current_timestamp);
 336                         }
 337                 }
 338         }
 339
 340         return pos;
 341
 342 error:
 343         return NULL;
 344 }
 345
 346 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 347                 uint64_t timestamp)
 348 {
 349         struct bt_iter_pos *pos;
 350
 351         pos = g_new0(struct bt_iter_pos, 1);
 352         pos->type = BT_SEEK_TIME;
 353         pos->u.seek_time = timestamp;
 354         return pos;
 355 }
 356
 357 /*
 358  * babeltrace_filestream_seek: seek a filestream to given position.
 359  *
 360  * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 361  */
 362 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
 363                 const struct bt_iter_pos *begin_pos,
 364                 unsigned long stream_id)
 365 {
 366         int ret = 0;
 367
 368         switch (begin_pos->type) {
 369         case BT_SEEK_CUR:
 370                 /*
 371                  * just insert into the heap we should already know
 372                  * the timestamps
 373                  */
 374                 break;
 375         case BT_SEEK_BEGIN:
 376                 file_stream->pos.packet_seek(&file_stream->pos.parent,
 377                                 0, SEEK_SET);
 378                 ret = stream_read_event(file_stream);
 379                 break;
 380         case BT_SEEK_TIME:
 381         case BT_SEEK_RESTORE:
 382         case BT_SEEK_END:
 383         default:
 384                 assert(0); /* Not yet defined */
 385         }
 386
 387         return ret;
 388 }
 389
 390 /*
 391  * bt_iter_seek: seek iterator to given position.
 392  */
 393 int bt_iter_seek(struct bt_iter *iter,
 394                 const struct bt_iter_pos *begin_pos)
 395 {
 396         int i, stream_id;
 397         int ret = 0;
 398         struct trace_collection *tc = iter->ctx->tc;
 399
 400         for (i = 0; i < tc->array->len; i++) {
 401                 struct ctf_trace *tin;
 402                 struct trace_descriptor *td_read;
 403
 404                 td_read = g_ptr_array_index(tc->array, i);
 405                 tin = container_of(td_read, struct ctf_trace, parent);
 406
 407                 /* Populate heap with each stream */
 408                 for (stream_id = 0; stream_id < tin->streams->len;
 409                                 stream_id++) {
 410                         struct ctf_stream_class *stream;
 411                         int filenr;
 412
 413                         stream = g_ptr_array_index(tin->streams, stream_id);
 414                         for (filenr = 0; filenr < stream->streams->len;
 415                                         filenr++) {
 416                                 struct ctf_file_stream *file_stream;
 417
 418                                 file_stream = g_ptr_array_index(stream->streams,
 419                                                 filenr);
 420                                 ret = babeltrace_filestream_seek(file_stream, begin_pos,
 421                                                 stream_id);
 422                                 if (ret < 0)
 423                                         goto end;
 424                         }
 425                 }
 426         }
 427 end:
 428         return ret;
 429 }
 430
 431 int bt_iter_init(struct bt_iter *iter,
 432                 struct bt_context *ctx,
 433                 const struct bt_iter_pos *begin_pos,
 434                 const struct bt_iter_pos *end_pos)
 435 {
 436         int i, stream_id;
 437         int ret = 0;
 438
 439         if (ctx->current_iterator) {
 440                 ret = -1;
 441                 goto error_ctx;
 442         }
 443
 444         iter->stream_heap = g_new(struct ptr_heap, 1);
 445         iter->end_pos = end_pos;
 446         bt_context_get(ctx);
 447         iter->ctx = ctx;
 448
 449         ret = heap_init(iter->stream_heap, 0, stream_compare);
 450         if (ret < 0)
 451                 goto error_heap_init;
 452
 453         for (i = 0; i < ctx->tc->array->len; i++) {
 454                 struct ctf_trace *tin;
 455                 struct trace_descriptor *td_read;
 456
 457                 td_read = g_ptr_array_index(ctx->tc->array, i);
 458                 tin = container_of(td_read, struct ctf_trace, parent);
 459
 460                 /* Populate heap with each stream */
 461                 for (stream_id = 0; stream_id < tin->streams->len;
 462                                 stream_id++) {
 463                         struct ctf_stream_class *stream;
 464                         int filenr;
 465
 466                         stream = g_ptr_array_index(tin->streams, stream_id);
 467                         if (!stream)
 468                                 continue;
 469                         for (filenr = 0; filenr < stream->streams->len;
 470                                         filenr++) {
 471                                 struct ctf_file_stream *file_stream;
 472
 473                                 file_stream = g_ptr_array_index(stream->streams,
 474                                                 filenr);
 475
 476                                 if (begin_pos) {
 477                                         ret = babeltrace_filestream_seek(
 478                                                         file_stream,
 479                                                         begin_pos,
 480                                                         stream_id);
 481                                 } else {
 482                                         struct bt_iter_pos pos;
 483                                         pos.type = BT_SEEK_BEGIN;
 484                                         ret = babeltrace_filestream_seek(
 485                                                         file_stream, &pos,
 486                                                         stream_id);
 487                                 }
 488                                 if (ret == EOF) {
 489                                         ret = 0;
 490                                         continue;
 491                                 } else if (ret) {
 492                                         goto error;
 493                                 }
 494                                 /* Add to heap */
 495                                 ret = heap_insert(iter->stream_heap, file_stream);
 496                                 if (ret)
 497                                         goto error;
 498                         }
 499                 }
 500         }
 501
 502         ctx->current_iterator = iter;
 503         return 0;
 504
 505 error:
 506         heap_free(iter->stream_heap);
 507 error_heap_init:
 508         g_free(iter->stream_heap);
 509 error_ctx:
 510         return ret;
 511 }
 512
 513 struct bt_iter *bt_iter_create(struct bt_context *ctx,
 514                 const struct bt_iter_pos *begin_pos,
 515                 const struct bt_iter_pos *end_pos)
 516 {
 517         struct bt_iter *iter;
 518         int ret;
 519
 520         iter = g_new0(struct bt_iter, 1);
 521         ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
 522         if (ret) {
 523                 g_free(iter);
 524                 return NULL;
 525         }
 526         return iter;
 527 }
 528
 529 void bt_iter_fini(struct bt_iter *iter)
 530 {
 531         if (iter->stream_heap) {
 532                 heap_free(iter->stream_heap);
 533                 g_free(iter->stream_heap);
 534         }
 535         iter->ctx->current_iterator = NULL;
 536         bt_context_put(iter->ctx);
 537 }
 538
 539 void bt_iter_destroy(struct bt_iter *iter)
 540 {
 541         bt_iter_fini(iter);
 542         g_free(iter);
 543 }
 544
 545 int bt_iter_next(struct bt_iter *iter)
 546 {
 547         struct ctf_file_stream *file_stream, *removed;
 548         int ret;
 549
 550         file_stream = heap_maximum(iter->stream_heap);
 551         if (!file_stream) {
 552                 /* end of file for all streams */
 553                 ret = 0;
 554                 goto end;
 555         }
 556
 557         ret = stream_read_event(file_stream);
 558         if (ret == EOF) {
 559                 removed = heap_remove(iter->stream_heap);
 560                 assert(removed == file_stream);
 561                 ret = 0;
 562                 goto end;
 563         } else if (ret) {
 564                 goto end;
 565         }
 566         /* Reinsert the file stream into the heap, and rebalance. */
 567         removed = heap_replace_max(iter->stream_heap, file_stream);
 568         assert(removed == file_stream);
 569
 570 end:
 571         return ret;
 572 }