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_TIME:
 229                 tc = iter->ctx->tc;
 230
 231                 heap_free(iter->stream_heap);
 232                 ret = heap_init(iter->stream_heap, 0, stream_compare);
 233                 if (ret < 0)
 234                         goto error;
 235
 236                 /* for each trace in the trace_collection */
 237                 for (i = 0; i < tc->array->len; i++) {
 238                         struct ctf_trace *tin;
 239                         struct trace_descriptor *td_read;
 240
 241                         td_read = g_ptr_array_index(tc->array, i);
 242                         tin = container_of(td_read, struct ctf_trace, parent);
 243
 244                         ret = seek_ctf_trace_by_timestamp(tin,
 245                                         iter_pos->u.seek_time,
 246                                         iter->stream_heap);
 247                         if (ret < 0)
 248                                 goto error;
 249                 }
 250                 return 0;
 251         default:
 252                 /* not implemented */
 253                 return -EINVAL;
 254         }
 255
 256         return 0;
 257
 258 error:
 259         heap_free(iter->stream_heap);
 260         if (heap_init(iter->stream_heap, 0, stream_compare) < 0) {
 261                 heap_free(iter->stream_heap);
 262                 g_free(iter->stream_heap);
 263                 iter->stream_heap = NULL;
 264                 ret = -ENOMEM;
 265         }
 266         return ret;
 267 }
 268
 269 struct bt_iter_pos *bt_iter_get_pos(struct bt_iter *iter)
 270 {
 271         struct bt_iter_pos *pos;
 272         struct trace_collection *tc = iter->ctx->tc;
 273         int i, stream_class_id, stream_id;
 274
 275         pos = g_new0(struct bt_iter_pos, 1);
 276         pos->u.restore = g_new0(struct bt_saved_pos, 1);
 277         pos->u.restore->tc = tc;
 278         pos->u.restore->stream_saved_pos = g_array_new(FALSE, TRUE,
 279                         sizeof(struct stream_saved_pos));
 280         if (!pos->u.restore->stream_saved_pos)
 281                 goto error;
 282
 283         for (i = 0; i < tc->array->len; i++) {
 284                 struct ctf_trace *tin;
 285                 struct trace_descriptor *td_read;
 286
 287                 td_read = g_ptr_array_index(tc->array, i);
 288                 tin = container_of(td_read, struct ctf_trace, parent);
 289
 290                 for (stream_class_id = 0; stream_class_id < tin->streams->len;
 291                                 stream_class_id++) {
 292                         struct ctf_stream_class *stream_class;
 293
 294                         stream_class = g_ptr_array_index(tin->streams,
 295                                         stream_class_id);
 296                         for (stream_id = 0;
 297                                         stream_id < stream_class->streams->len;
 298                                         stream_id++) {
 299                                 struct ctf_stream *stream;
 300                                 struct ctf_file_stream *cfs;
 301                                 struct stream_saved_pos saved_pos;
 302
 303                                 stream = g_ptr_array_index(
 304                                                 stream_class->streams,
 305                                                 stream_id);
 306                                 cfs = container_of(stream,
 307                                                 struct ctf_file_stream,
 308                                                 parent);
 309
 310                                 saved_pos.file_stream = cfs;
 311                                 saved_pos.cur_index = cfs->pos.cur_index;
 312
 313                                 /*
 314                                  * It is possible that an event was read during
 315                                  * the last restore, never consumed and its
 316                                  * position saved again.  For this case, we
 317                                  * need to check if the event really was
 318                                  * consumed by the caller otherwise it is lost.
 319                                  */
 320                                 if (stream->consumed)
 321                                         saved_pos.offset = cfs->pos.offset;
 322                                 else
 323                                         saved_pos.offset = cfs->pos.last_offset;
 324
 325                                 saved_pos.current_timestamp = stream->timestamp;
 326
 327                                 g_array_append_val(
 328                                         pos->u.restore->stream_saved_pos,
 329                                         saved_pos);
 330
 331                                 printf_debug("stream : %" PRIu64 ", cur_index : %zd, "
 332                                         "offset : %zd, "
 333                                         "timestamp = %" PRIu64 "\n",
 334                                         stream->stream_id, saved_pos.cur_index,
 335                                         saved_pos.offset,
 336                                         saved_pos.current_timestamp);
 337                         }
 338                 }
 339         }
 340
 341         return pos;
 342
 343 error:
 344         return NULL;
 345 }
 346
 347 struct bt_iter_pos *bt_iter_create_time_pos(struct bt_iter *iter,
 348                 uint64_t timestamp)
 349 {
 350         struct bt_iter_pos *pos;
 351
 352         pos = g_new0(struct bt_iter_pos, 1);
 353         pos->type = BT_SEEK_TIME;
 354         pos->u.seek_time = timestamp;
 355         return pos;
 356 }
 357
 358 /*
 359  * babeltrace_filestream_seek: seek a filestream to given position.
 360  *
 361  * The stream_id parameter is only useful for BT_SEEK_RESTORE.
 362  */
 363 static int babeltrace_filestream_seek(struct ctf_file_stream *file_stream,
 364                 const struct bt_iter_pos *begin_pos,
 365                 unsigned long stream_id)
 366 {
 367         int ret = 0;
 368
 369         switch (begin_pos->type) {
 370         case BT_SEEK_CUR:
 371                 /*
 372                  * just insert into the heap we should already know
 373                  * the timestamps
 374                  */
 375                 break;
 376         case BT_SEEK_BEGIN:
 377                 file_stream->pos.packet_seek(&file_stream->pos.parent,
 378                                 0, SEEK_SET);
 379                 ret = stream_read_event(file_stream);
 380                 break;
 381         case BT_SEEK_TIME:
 382         case BT_SEEK_RESTORE:
 383         case BT_SEEK_END:
 384         default:
 385                 assert(0); /* Not yet defined */
 386         }
 387
 388         return ret;
 389 }
 390
 391 /*
 392  * bt_iter_seek: seek iterator to given position.
 393  */
 394 int bt_iter_seek(struct bt_iter *iter,
 395                 const struct bt_iter_pos *begin_pos)
 396 {
 397         int i, stream_id;
 398         int ret = 0;
 399         struct trace_collection *tc = iter->ctx->tc;
 400
 401         for (i = 0; i < tc->array->len; i++) {
 402                 struct ctf_trace *tin;
 403                 struct trace_descriptor *td_read;
 404
 405                 td_read = g_ptr_array_index(tc->array, i);
 406                 tin = container_of(td_read, struct ctf_trace, parent);
 407
 408                 /* Populate heap with each stream */
 409                 for (stream_id = 0; stream_id < tin->streams->len;
 410                                 stream_id++) {
 411                         struct ctf_stream_class *stream;
 412                         int filenr;
 413
 414                         stream = g_ptr_array_index(tin->streams, stream_id);
 415                         for (filenr = 0; filenr < stream->streams->len;
 416                                         filenr++) {
 417                                 struct ctf_file_stream *file_stream;
 418
 419                                 file_stream = g_ptr_array_index(stream->streams,
 420                                                 filenr);
 421                                 ret = babeltrace_filestream_seek(file_stream, begin_pos,
 422                                                 stream_id);
 423                                 if (ret < 0)
 424                                         goto end;
 425                         }
 426                 }
 427         }
 428 end:
 429         return ret;
 430 }
 431
 432 int bt_iter_init(struct bt_iter *iter,
 433                 struct bt_context *ctx,
 434                 struct bt_iter_pos *begin_pos,
 435                 struct bt_iter_pos *end_pos)
 436 {
 437         int i, stream_id;
 438         int ret = 0;
 439
 440         iter->stream_heap = g_new(struct ptr_heap, 1);
 441         iter->end_pos = end_pos;
 442         bt_context_get(ctx);
 443         iter->ctx = ctx;
 444
 445         ret = heap_init(iter->stream_heap, 0, stream_compare);
 446         if (ret < 0)
 447                 goto error_heap_init;
 448
 449         for (i = 0; i < ctx->tc->array->len; i++) {
 450                 struct ctf_trace *tin;
 451                 struct trace_descriptor *td_read;
 452
 453                 td_read = g_ptr_array_index(ctx->tc->array, i);
 454                 tin = container_of(td_read, struct ctf_trace, parent);
 455
 456                 /* Populate heap with each stream */
 457                 for (stream_id = 0; stream_id < tin->streams->len;
 458                                 stream_id++) {
 459                         struct ctf_stream_class *stream;
 460                         int filenr;
 461
 462                         stream = g_ptr_array_index(tin->streams, stream_id);
 463                         if (!stream)
 464                                 continue;
 465                         for (filenr = 0; filenr < stream->streams->len;
 466                                         filenr++) {
 467                                 struct ctf_file_stream *file_stream;
 468
 469                                 file_stream = g_ptr_array_index(stream->streams,
 470                                                 filenr);
 471
 472                                 if (begin_pos) {
 473                                     ret = babeltrace_filestream_seek(file_stream, begin_pos,
 474                                                         stream_id);
 475                                     if (ret == EOF) {
 476                                            ret = 0;
 477                                            continue;
 478                                     } else if (ret) {
 479                                            goto error;
 480                                     }
 481                                 }
 482                                 /* Add to heap */
 483                                 ret = heap_insert(iter->stream_heap, file_stream);
 484                                 if (ret)
 485                                         goto error;
 486                         }
 487                 }
 488         }
 489
 490         return 0;
 491
 492 error:
 493         heap_free(iter->stream_heap);
 494 error_heap_init:
 495         g_free(iter->stream_heap);
 496         return ret;
 497 }
 498
 499 struct bt_iter *bt_iter_create(struct bt_context *ctx,
 500                 struct bt_iter_pos *begin_pos,
 501                 struct bt_iter_pos *end_pos)
 502 {
 503         struct bt_iter *iter;
 504         int ret;
 505
 506         iter = g_new0(struct bt_iter, 1);
 507         ret = bt_iter_init(iter, ctx, begin_pos, end_pos);
 508         if (ret) {
 509                 g_free(iter);
 510                 return NULL;
 511         }
 512         return iter;
 513 }
 514
 515 void bt_iter_fini(struct bt_iter *iter)
 516 {
 517         if (iter->stream_heap) {
 518                 heap_free(iter->stream_heap);
 519                 g_free(iter->stream_heap);
 520         }
 521         bt_context_put(iter->ctx);
 522 }
 523
 524 void bt_iter_destroy(struct bt_iter *iter)
 525 {
 526         bt_iter_fini(iter);
 527         g_free(iter);
 528 }
 529
 530 int bt_iter_next(struct bt_iter *iter)
 531 {
 532         struct ctf_file_stream *file_stream, *removed;
 533         int ret;
 534
 535         file_stream = heap_maximum(iter->stream_heap);
 536         if (!file_stream) {
 537                 /* end of file for all streams */
 538                 ret = 0;
 539                 goto end;
 540         }
 541
 542         ret = stream_read_event(file_stream);
 543         if (ret == EOF) {
 544                 removed = heap_remove(iter->stream_heap);
 545                 assert(removed == file_stream);
 546                 ret = 0;
 547                 goto end;
 548         } else if (ret) {
 549                 goto end;
 550         }
 551         /* Reinsert the file stream into the heap, and rebalance. */
 552         removed = heap_replace_max(iter->stream_heap, file_stream);
 553         assert(removed == file_stream);
 554
 555 end:
 556         return ret;
 557 }