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