src/lib/graph/iterator.c

   1 /*
   2  * SPDX-License-Identifier: MIT
   3  *
   4  * Copyright 2017-2018 Philippe Proulx <pproulx@efficios.com>
   5  * Copyright 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
   6  */
   7
   8 #define BT_LOG_TAG "LIB/MSG-ITER"
   9 #include "lib/logging.h"
  10
  11 #include "compat/compiler.h"
  12 #include "compat/glib.h"
  13 #include "lib/trace-ir/clock-class.h"
  14 #include "lib/trace-ir/clock-snapshot.h"
  15 #include <babeltrace2/trace-ir/field.h>
  16 #include <babeltrace2/trace-ir/event.h>
  17 #include "lib/trace-ir/event.h"
  18 #include <babeltrace2/trace-ir/packet.h>
  19 #include "lib/trace-ir/packet.h"
  20 #include "lib/trace-ir/stream.h"
  21 #include <babeltrace2/trace-ir/clock-class.h>
  22 #include <babeltrace2/trace-ir/stream-class.h>
  23 #include <babeltrace2/trace-ir/stream.h>
  24 #include <babeltrace2/graph/connection.h>
  25 #include <babeltrace2/graph/component.h>
  26 #include <babeltrace2/graph/message.h>
  27 #include <babeltrace2/graph/self-component.h>
  28 #include <babeltrace2/graph/port.h>
  29 #include <babeltrace2/graph/graph.h>
  30 #include <babeltrace2/graph/message-iterator.h>
  31 #include <babeltrace2/types.h>
  32 #include "common/assert.h"
  33 #include "lib/assert-cond.h"
  34 #include <stdint.h>
  35 #include <inttypes.h>
  36 #include <stdbool.h>
  37 #include <stdlib.h>
  38
  39 #include "component-class.h"
  40 #include "component.h"
  41 #include "component-sink.h"
  42 #include "component-source.h"
  43 #include "connection.h"
  44 #include "graph.h"
  45 #include "message-iterator-class.h"
  46 #include "message/discarded-items.h"
  47 #include "message/event.h"
  48 #include "message/iterator.h"
  49 #include "message/message.h"
  50 #include "message/message-iterator-inactivity.h"
  51 #include "message/stream.h"
  52 #include "message/packet.h"
  53 #include "lib/func-status.h"
  54
  55 /*
  56  * TODO: Use graph's state (number of active iterators, etc.) and
  57  * possibly system specifications to make a better guess than this.
  58  */
  59 #define MSG_BATCH_SIZE  15
  60
  61 #define BT_ASSERT_PRE_ITER_HAS_STATE_TO_SEEK(_iter)                     \
  62         BT_ASSERT_PRE("has-state-to-seek",                              \
  63                 (_iter)->state == BT_MESSAGE_ITERATOR_STATE_ACTIVE ||   \
  64                 (_iter)->state == BT_MESSAGE_ITERATOR_STATE_ENDED ||    \
  65                 (_iter)->state == BT_MESSAGE_ITERATOR_STATE_LAST_SEEKING_RETURNED_AGAIN || \
  66                 (_iter)->state == BT_MESSAGE_ITERATOR_STATE_LAST_SEEKING_RETURNED_ERROR, \
  67                 "Message iterator is in the wrong state: %!+i", (_iter))
  68
  69 static inline
  70 void set_msg_iterator_state(struct bt_message_iterator *iterator,
  71                 enum bt_message_iterator_state state)
  72 {
  73         BT_ASSERT_DBG(iterator);
  74         BT_LIB_LOGD("Updating message iterator's state: new-state=%s",
  75                 bt_message_iterator_state_string(state));
  76         iterator->state = state;
  77 }
  78
  79 static
  80 void bt_message_iterator_destroy(struct bt_object *obj)
  81 {
  82         struct bt_message_iterator *iterator;
  83
  84         BT_ASSERT(obj);
  85
  86         /*
  87          * The message iterator's reference count is 0 if we're
  88          * here. Increment it to avoid a double-destroy (possibly
  89          * infinitely recursive). This could happen for example if the
  90          * message iterator's finalization function does
  91          * bt_object_get_ref() (or anything that causes
  92          * bt_object_get_ref() to be called) on itself (ref. count goes
  93          * from 0 to 1), and then bt_object_put_ref(): the reference
  94          * count would go from 1 to 0 again and this function would be
  95          * called again.
  96          */
  97         obj->ref_count++;
  98         iterator = (void *) obj;
  99         BT_LIB_LOGI("Destroying self component input port message iterator object: "
 100                 "%!+i", iterator);
 101         bt_message_iterator_try_finalize(iterator);
 102
 103         if (iterator->connection) {
 104                 /*
 105                  * Remove ourself from the originating connection so
 106                  * that it does not try to finalize a dangling pointer
 107                  * later.
 108                  */
 109                 bt_connection_remove_iterator(iterator->connection, iterator);
 110                 iterator->connection = NULL;
 111         }
 112
 113         if (iterator->auto_seek.msgs) {
 114                 while (!g_queue_is_empty(iterator->auto_seek.msgs)) {
 115                         bt_object_put_ref_no_null_check(
 116                                 g_queue_pop_tail(iterator->auto_seek.msgs));
 117                 }
 118
 119                 g_queue_free(iterator->auto_seek.msgs);
 120                 iterator->auto_seek.msgs = NULL;
 121         }
 122
 123         if (iterator->upstream_msg_iters) {
 124                 /*
 125                  * At this point the message iterator is finalized, so
 126                  * it's detached from any upstream message iterator.
 127                  */
 128                 BT_ASSERT(iterator->upstream_msg_iters->len == 0);
 129                 g_ptr_array_free(iterator->upstream_msg_iters, TRUE);
 130                 iterator->upstream_msg_iters = NULL;
 131         }
 132
 133         if (iterator->msgs) {
 134                 g_ptr_array_free(iterator->msgs, TRUE);
 135                 iterator->msgs = NULL;
 136         }
 137
 138         g_free(iterator);
 139 }
 140
 141 BT_HIDDEN
 142 void bt_message_iterator_try_finalize(
 143                 struct bt_message_iterator *iterator)
 144 {
 145         uint64_t i;
 146         bool call_user_finalize = true;
 147
 148         BT_ASSERT(iterator);
 149
 150         switch (iterator->state) {
 151         case BT_MESSAGE_ITERATOR_STATE_NON_INITIALIZED:
 152                 /*
 153                  * If this function is called while the iterator is in the
 154                  * NON_INITIALIZED state, it means the user initialization
 155                  * method has either not been called, or has failed.  We
 156                  * therefore don't want to call the user finalization method.
 157                  * However, the initialization method might have created some
 158                  * upstream message iterators before failing, so we want to
 159                  * execute the rest of this function, which unlinks the related
 160                  * iterators.
 161                  */
 162                 call_user_finalize = false;
 163                 break;
 164         case BT_MESSAGE_ITERATOR_STATE_FINALIZED:
 165                 /* Already finalized */
 166                 BT_LIB_LOGD("Not finalizing message iterator: already finalized: "
 167                         "%!+i", iterator);
 168                 goto end;
 169         case BT_MESSAGE_ITERATOR_STATE_FINALIZING:
 170                 /* Finalizing */
 171                 BT_LIB_LOGF("Message iterator is already being finalized: "
 172                         "%!+i", iterator);
 173                 bt_common_abort();
 174         default:
 175                 break;
 176         }
 177
 178         BT_LIB_LOGD("Finalizing message iterator: %!+i", iterator);
 179         set_msg_iterator_state(iterator,
 180                 BT_MESSAGE_ITERATOR_STATE_FINALIZING);
 181         BT_ASSERT(iterator->upstream_component);
 182
 183         /* Call user-defined destroy method */
 184         if (call_user_finalize) {
 185                 typedef void (*method_t)(void *);
 186                 method_t method;
 187                 struct bt_component_class *comp_class =
 188                         iterator->upstream_component->class;
 189                 struct bt_component_class_with_iterator_class *class_with_iter_class;
 190
 191                 BT_ASSERT(bt_component_class_has_message_iterator_class(comp_class));
 192                 class_with_iter_class = container_of(comp_class,
 193                         struct bt_component_class_with_iterator_class, parent);
 194                 method = (method_t) class_with_iter_class->msg_iter_cls->methods.finalize;
 195
 196                 if (method) {
 197                         const bt_error *saved_error;
 198
 199                         saved_error = bt_current_thread_take_error();
 200
 201                         BT_LIB_LOGD("Calling user's finalization method: %!+i",
 202                                 iterator);
 203                         method(iterator);
 204                         BT_ASSERT_POST_NO_ERROR("bt_message_iterator_class_finalize_method");
 205
 206                         if (saved_error) {
 207                                 BT_CURRENT_THREAD_MOVE_ERROR_AND_RESET(saved_error);
 208                         }
 209                 }
 210         }
 211
 212         /* Detach upstream message iterators */
 213         for (i = 0; i < iterator->upstream_msg_iters->len; i++) {
 214                 struct bt_message_iterator *upstream_msg_iter =
 215                         iterator->upstream_msg_iters->pdata[i];
 216
 217                 upstream_msg_iter->downstream_msg_iter = NULL;
 218         }
 219
 220         g_ptr_array_set_size(iterator->upstream_msg_iters, 0);
 221
 222         /* Detach downstream message iterator */
 223         if (iterator->downstream_msg_iter) {
 224                 gboolean existed;
 225
 226                 BT_ASSERT(iterator->downstream_msg_iter->upstream_msg_iters);
 227                 existed = g_ptr_array_remove_fast(
 228                         iterator->downstream_msg_iter->upstream_msg_iters,
 229                         iterator);
 230                 BT_ASSERT(existed);
 231         }
 232
 233         iterator->upstream_component = NULL;
 234         iterator->upstream_port = NULL;
 235         set_msg_iterator_state(iterator,
 236                 BT_MESSAGE_ITERATOR_STATE_FINALIZED);
 237         BT_LIB_LOGD("Finalized message iterator: %!+i", iterator);
 238
 239 end:
 240         return;
 241 }
 242
 243 BT_HIDDEN
 244 void bt_message_iterator_set_connection(
 245                 struct bt_message_iterator *iterator,
 246                 struct bt_connection *connection)
 247 {
 248         BT_ASSERT(iterator);
 249         iterator->connection = connection;
 250         BT_LIB_LOGI("Set message iterator's connection: "
 251                 "%![iter-]+i, %![conn-]+x", iterator, connection);
 252 }
 253
 254 static
 255 enum bt_message_iterator_can_seek_beginning_status can_seek_ns_from_origin_true(
 256                 struct bt_message_iterator *iterator,
 257                 int64_t ns_from_origin, bt_bool *can_seek)
 258 {
 259         *can_seek = BT_TRUE;
 260
 261         return BT_FUNC_STATUS_OK;
 262 }
 263
 264 static
 265 enum bt_message_iterator_can_seek_beginning_status can_seek_beginning_true(
 266                 struct bt_message_iterator *iterator,
 267                 bt_bool *can_seek)
 268 {
 269         *can_seek = BT_TRUE;
 270
 271         return BT_FUNC_STATUS_OK;
 272 }
 273
 274 static
 275 int create_self_component_input_port_message_iterator(
 276                 struct bt_self_message_iterator *self_downstream_msg_iter,
 277                 struct bt_self_component_port_input *self_port,
 278                 struct bt_message_iterator **message_iterator,
 279                 const char *api_func)
 280 {
 281         bt_message_iterator_class_initialize_method init_method = NULL;
 282         struct bt_message_iterator *iterator =
 283                 NULL;
 284         struct bt_message_iterator *downstream_msg_iter =
 285                 (void *) self_downstream_msg_iter;
 286         struct bt_port *port = (void *) self_port;
 287         struct bt_port *upstream_port;
 288         struct bt_component *comp;
 289         struct bt_component *upstream_comp;
 290         struct bt_component_class *upstream_comp_cls;
 291         struct bt_component_class_with_iterator_class *upstream_comp_cls_with_iter_cls;
 292         int status;
 293
 294         BT_ASSERT_PRE_NON_NULL_FROM_FUNC(api_func, "message-iterator-output",
 295                 message_iterator, "Created message iterator (output)");
 296         BT_ASSERT_PRE_NON_NULL_FROM_FUNC(api_func, "input-port", port,
 297                 "Input port");
 298         comp = bt_port_borrow_component_inline(port);
 299         BT_ASSERT_PRE_FROM_FUNC(api_func, "input-port-is-connected",
 300                 bt_port_is_connected(port),
 301                 "Input port is not connected: %![port-]+p", port);
 302         BT_ASSERT_PRE_FROM_FUNC(api_func, "input-port-has-component",
 303                 comp, "Input port is not part of a component: %![port-]+p",
 304                 port);
 305         BT_ASSERT(port->connection);
 306         upstream_port = port->connection->upstream_port;
 307         BT_ASSERT(upstream_port);
 308         upstream_comp = bt_port_borrow_component_inline(upstream_port);
 309         BT_ASSERT(upstream_comp);
 310         BT_ASSERT_PRE_FROM_FUNC(api_func, "graph-is-configured",
 311                 bt_component_borrow_graph(upstream_comp)->config_state ==
 312                         BT_GRAPH_CONFIGURATION_STATE_PARTIALLY_CONFIGURED ||
 313                 bt_component_borrow_graph(upstream_comp)->config_state ==
 314                         BT_GRAPH_CONFIGURATION_STATE_CONFIGURED,
 315                 "Graph is not configured: %!+g",
 316                 bt_component_borrow_graph(upstream_comp));
 317         upstream_comp_cls = upstream_comp->class;
 318         BT_ASSERT(upstream_comp->class->type ==
 319                 BT_COMPONENT_CLASS_TYPE_SOURCE ||
 320                 upstream_comp->class->type ==
 321                 BT_COMPONENT_CLASS_TYPE_FILTER);
 322         BT_LIB_LOGI("Creating message iterator on self component input port: "
 323                 "%![up-comp-]+c, %![up-port-]+p", upstream_comp, upstream_port);
 324         iterator = g_new0(
 325                 struct bt_message_iterator, 1);
 326         if (!iterator) {
 327                 BT_LIB_LOGE_APPEND_CAUSE(
 328                         "Failed to allocate one self component input port "
 329                         "message iterator.");
 330                 status = BT_FUNC_STATUS_MEMORY_ERROR;
 331                 goto error;
 332         }
 333
 334         bt_object_init_shared(&iterator->base,
 335                 bt_message_iterator_destroy);
 336         iterator->msgs = g_ptr_array_new();
 337         if (!iterator->msgs) {
 338                 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate a GPtrArray.");
 339                 status = BT_FUNC_STATUS_MEMORY_ERROR;
 340                 goto error;
 341         }
 342
 343         g_ptr_array_set_size(iterator->msgs, MSG_BATCH_SIZE);
 344         iterator->last_ns_from_origin = INT64_MIN;
 345         iterator->auto_seek.msgs = g_queue_new();
 346         if (!iterator->auto_seek.msgs) {
 347                 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate a GQueue.");
 348                 status = BT_FUNC_STATUS_MEMORY_ERROR;
 349                 goto error;
 350         }
 351
 352         iterator->upstream_msg_iters = g_ptr_array_new();
 353         if (!iterator->upstream_msg_iters) {
 354                 BT_LIB_LOGE_APPEND_CAUSE("Failed to allocate a GPtrArray.");
 355                 status = BT_FUNC_STATUS_MEMORY_ERROR;
 356                 goto error;
 357         }
 358
 359         iterator->upstream_component = upstream_comp;
 360         iterator->upstream_port = upstream_port;
 361         iterator->connection = iterator->upstream_port->connection;
 362         iterator->graph = bt_component_borrow_graph(upstream_comp);
 363         set_msg_iterator_state(iterator,
 364                 BT_MESSAGE_ITERATOR_STATE_NON_INITIALIZED);
 365
 366         /* Copy methods from the message iterator class to the message iterator. */
 367         BT_ASSERT(bt_component_class_has_message_iterator_class(upstream_comp_cls));
 368         upstream_comp_cls_with_iter_cls = container_of(upstream_comp_cls,
 369                 struct bt_component_class_with_iterator_class, parent);
 370
 371         iterator->methods.next =
 372                 (bt_message_iterator_next_method)
 373                         upstream_comp_cls_with_iter_cls->msg_iter_cls->methods.next;
 374         iterator->methods.seek_ns_from_origin =
 375                 (bt_message_iterator_seek_ns_from_origin_method)
 376                         upstream_comp_cls_with_iter_cls->msg_iter_cls->methods.seek_ns_from_origin;
 377         iterator->methods.seek_beginning =
 378                 (bt_message_iterator_seek_beginning_method)
 379                         upstream_comp_cls_with_iter_cls->msg_iter_cls->methods.seek_beginning;
 380         iterator->methods.can_seek_ns_from_origin =
 381                 (bt_message_iterator_can_seek_ns_from_origin_method)
 382                         upstream_comp_cls_with_iter_cls->msg_iter_cls->methods.can_seek_ns_from_origin;
 383         iterator->methods.can_seek_beginning =
 384                 (bt_message_iterator_can_seek_beginning_method)
 385                         upstream_comp_cls_with_iter_cls->msg_iter_cls->methods.can_seek_beginning;
 386
 387         if (iterator->methods.seek_ns_from_origin &&
 388                         !iterator->methods.can_seek_ns_from_origin) {
 389                 iterator->methods.can_seek_ns_from_origin =
 390                         (bt_message_iterator_can_seek_ns_from_origin_method)
 391                                 can_seek_ns_from_origin_true;
 392         }
 393
 394         if (iterator->methods.seek_beginning &&
 395                         !iterator->methods.can_seek_beginning) {
 396                 iterator->methods.can_seek_beginning =
 397                         (bt_message_iterator_can_seek_beginning_method)
 398                                 can_seek_beginning_true;
 399         }
 400
 401         /* Call iterator's init method. */
 402         init_method = upstream_comp_cls_with_iter_cls->msg_iter_cls->methods.initialize;
 403
 404         if (init_method) {
 405                 enum bt_message_iterator_class_initialize_method_status iter_status;
 406
 407                 BT_LIB_LOGD("Calling user's initialization method: %!+i", iterator);
 408                 iter_status = init_method(
 409                         (struct bt_self_message_iterator *) iterator,
 410                         &iterator->config,
 411                         (struct bt_self_component_port_output *) upstream_port);
 412                 BT_LOGD("User method returned: status=%s",
 413                         bt_common_func_status_string(iter_status));
 414                 BT_ASSERT_POST_NO_ERROR_IF_NO_ERROR_STATUS(
 415                         "bt_message_iterator_class_initialize_method",
 416                         iter_status);
 417                 if (iter_status != BT_FUNC_STATUS_OK) {
 418                         BT_LIB_LOGW_APPEND_CAUSE(
 419                                 "Component input port message iterator initialization method failed: "
 420                                 "%![iter-]+i, status=%s",
 421                                 iterator,
 422                                 bt_common_func_status_string(iter_status));
 423                         status = iter_status;
 424                         goto error;
 425                 }
 426
 427                 iterator->config.frozen = true;
 428         }
 429
 430         if (downstream_msg_iter) {
 431                 /* Set this message iterator's downstream message iterator */
 432                 iterator->downstream_msg_iter = downstream_msg_iter;
 433
 434                 /*
 435                  * Add this message iterator to the downstream message
 436                  * iterator's array of upstream message iterators.
 437                  */
 438                 g_ptr_array_add(downstream_msg_iter->upstream_msg_iters,
 439                         iterator);
 440         }
 441
 442         set_msg_iterator_state(iterator,
 443                 BT_MESSAGE_ITERATOR_STATE_ACTIVE);
 444         g_ptr_array_add(port->connection->iterators, iterator);
 445         BT_LIB_LOGI("Created message iterator on self component input port: "
 446                 "%![up-port-]+p, %![up-comp-]+c, %![iter-]+i",
 447                 upstream_port, upstream_comp, iterator);
 448
 449         *message_iterator = iterator;
 450         status = BT_FUNC_STATUS_OK;
 451         goto end;
 452
 453 error:
 454         BT_OBJECT_PUT_REF_AND_RESET(iterator);
 455
 456 end:
 457         return status;
 458 }
 459
 460 bt_message_iterator_create_from_message_iterator_status
 461 bt_message_iterator_create_from_message_iterator(
 462                 struct bt_self_message_iterator *self_msg_iter,
 463                 struct bt_self_component_port_input *input_port,
 464                 struct bt_message_iterator **message_iterator)
 465 {
 466         BT_ASSERT_PRE_NO_ERROR();
 467         BT_ASSERT_PRE_MSG_ITER_NON_NULL(self_msg_iter);
 468         return create_self_component_input_port_message_iterator(self_msg_iter,
 469                 input_port, message_iterator, __func__);
 470 }
 471
 472 bt_message_iterator_create_from_sink_component_status
 473 bt_message_iterator_create_from_sink_component(
 474                 struct bt_self_component_sink *self_comp,
 475                 struct bt_self_component_port_input *input_port,
 476                 struct bt_message_iterator **message_iterator)
 477 {
 478         BT_ASSERT_PRE_NO_ERROR();
 479         BT_ASSERT_PRE_NON_NULL("sink-component", self_comp, "Sink component");
 480         return create_self_component_input_port_message_iterator(NULL,
 481                 input_port, message_iterator, __func__);
 482 }
 483
 484 void *bt_self_message_iterator_get_data(
 485                 const struct bt_self_message_iterator *self_iterator)
 486 {
 487         struct bt_message_iterator *iterator =
 488                 (void *) self_iterator;
 489
 490         BT_ASSERT_PRE_DEV_MSG_ITER_NON_NULL(iterator);
 491         return iterator->user_data;
 492 }
 493
 494 void bt_self_message_iterator_set_data(
 495                 struct bt_self_message_iterator *self_iterator, void *data)
 496 {
 497         struct bt_message_iterator *iterator =
 498                 (void *) self_iterator;
 499
 500         BT_ASSERT_PRE_DEV_MSG_ITER_NON_NULL(iterator);
 501         iterator->user_data = data;
 502         BT_LIB_LOGD("Set message iterator's user data: "
 503                 "%!+i, user-data-addr=%p", iterator, data);
 504 }
 505
 506 void bt_self_message_iterator_configuration_set_can_seek_forward(
 507                 bt_self_message_iterator_configuration *config,
 508                 bt_bool can_seek_forward)
 509 {
 510         BT_ASSERT_PRE_NON_NULL("message-iterator-configuration", config,
 511                 "Message iterator configuration");
 512         BT_ASSERT_PRE_DEV_HOT("message-iterator-configuration", config,
 513                 "Message iterator configuration", "");
 514
 515         config->can_seek_forward = can_seek_forward;
 516 }
 517
 518 /*
 519  * Validate that the default clock snapshot in `msg` doesn't make us go back in
 520  * time.
 521  */
 522
 523 BT_ASSERT_COND_DEV_FUNC
 524 static
 525 bool clock_snapshots_are_monotonic_one(
 526                 struct bt_message_iterator *iterator,
 527                 const bt_message *msg)
 528 {
 529         const struct bt_clock_snapshot *clock_snapshot = NULL;
 530         bt_message_type message_type = bt_message_get_type(msg);
 531         int64_t ns_from_origin;
 532         enum bt_clock_snapshot_get_ns_from_origin_status clock_snapshot_status;
 533
 534         /*
 535          * The default is true: if we can't figure out the clock snapshot
 536          * (or there is none), assume it is fine.
 537          */
 538         bool result = true;
 539
 540         switch (message_type) {
 541         case BT_MESSAGE_TYPE_EVENT:
 542         {
 543                 struct bt_message_event *event_msg = (struct bt_message_event *) msg;
 544                 clock_snapshot = event_msg->default_cs;
 545                 break;
 546         }
 547         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
 548         {
 549                 struct bt_message_message_iterator_inactivity *inactivity_msg =
 550                         (struct bt_message_message_iterator_inactivity *) msg;
 551                 clock_snapshot = inactivity_msg->cs;
 552                 break;
 553         }
 554         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
 555         case BT_MESSAGE_TYPE_PACKET_END:
 556         {
 557                 struct bt_message_packet *packet_msg = (struct bt_message_packet *) msg;
 558                 clock_snapshot = packet_msg->default_cs;
 559                 break;
 560         }
 561         case BT_MESSAGE_TYPE_STREAM_BEGINNING:
 562         case BT_MESSAGE_TYPE_STREAM_END:
 563         {
 564                 struct bt_message_stream *stream_msg = (struct bt_message_stream *) msg;
 565                 if (stream_msg->default_cs_state != BT_MESSAGE_STREAM_CLOCK_SNAPSHOT_STATE_KNOWN) {
 566                         goto end;
 567                 }
 568
 569                 clock_snapshot = stream_msg->default_cs;
 570                 break;
 571         }
 572         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
 573         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
 574         {
 575                 struct bt_message_discarded_items *discarded_msg =
 576                         (struct bt_message_discarded_items *) msg;
 577
 578                 clock_snapshot = discarded_msg->default_begin_cs;
 579                 break;
 580         }
 581         }
 582
 583         if (!clock_snapshot) {
 584                 goto end;
 585         }
 586
 587         clock_snapshot_status = bt_clock_snapshot_get_ns_from_origin(
 588                 clock_snapshot, &ns_from_origin);
 589         if (clock_snapshot_status != BT_FUNC_STATUS_OK) {
 590                 /*
 591                  * bt_clock_snapshot_get_ns_from_origin can return
 592                  * OVERFLOW_ERROR.  We don't really want to report an error to
 593                  * our caller, so just clear it.
 594                  */
 595                 bt_current_thread_clear_error();
 596                 goto end;
 597         }
 598
 599         result = ns_from_origin >= iterator->last_ns_from_origin;
 600         iterator->last_ns_from_origin = ns_from_origin;
 601 end:
 602         return result;
 603 }
 604
 605 BT_ASSERT_COND_DEV_FUNC
 606 static
 607 bool clock_snapshots_are_monotonic(
 608                 struct bt_message_iterator *iterator,
 609                 bt_message_array_const msgs, uint64_t msg_count)
 610 {
 611         uint64_t i;
 612         bool result;
 613
 614         for (i = 0; i < msg_count; i++) {
 615                 if (!clock_snapshots_are_monotonic_one(iterator, msgs[i])) {
 616                         result = false;
 617                         goto end;
 618                 }
 619         }
 620
 621         result = true;
 622
 623 end:
 624         return result;
 625 }
 626
 627 /*
 628  * When a new stream begins, verify that the clock class tied to this
 629  * stream is compatible with what we've seen before.
 630  */
 631
 632 BT_ASSERT_COND_DEV_FUNC
 633 static
 634 bool clock_classes_are_compatible_one(struct bt_message_iterator *iterator,
 635                 const struct bt_message *msg)
 636 {
 637         enum bt_message_type message_type = bt_message_get_type(msg);
 638         bool result;
 639
 640         if (message_type == BT_MESSAGE_TYPE_STREAM_BEGINNING) {
 641                 const struct bt_message_stream *stream_msg = (struct bt_message_stream *) msg;
 642                 const struct bt_clock_class *clock_class = stream_msg->stream->class->default_clock_class;
 643                 bt_uuid clock_class_uuid = NULL;
 644
 645                 if (clock_class) {
 646                         clock_class_uuid = bt_clock_class_get_uuid(clock_class);
 647                 }
 648
 649                 switch (iterator->clock_expectation.type) {
 650                 case CLOCK_EXPECTATION_UNSET:
 651                         /*
 652                          * This is the first time we see a message with a clock
 653                          * snapshot: record the properties of that clock, against
 654                          * which we'll compare the clock properties of the following
 655                          * messages.
 656                          */
 657
 658                         if (!clock_class) {
 659                                 iterator->clock_expectation.type = CLOCK_EXPECTATION_NONE;
 660                         } else if (bt_clock_class_origin_is_unix_epoch(clock_class)) {
 661                                 iterator->clock_expectation.type = CLOCK_EXPECTATION_ORIGIN_UNIX;
 662                         } else if (clock_class_uuid) {
 663                                 iterator->clock_expectation.type = CLOCK_EXPECTATION_ORIGIN_OTHER_UUID;
 664                                 bt_uuid_copy(iterator->clock_expectation.uuid, clock_class_uuid);
 665                         } else {
 666                                 iterator->clock_expectation.type = CLOCK_EXPECTATION_ORIGIN_OTHER_NO_UUID;
 667                         }
 668                         break;
 669
 670                 case CLOCK_EXPECTATION_NONE:
 671                         if (clock_class) {
 672                                 BT_ASSERT_COND_DEV_MSG(
 673                                         "Expecting no clock class, got one: %![cc-]+K",
 674                                         clock_class);
 675                                 result = false;
 676                                 goto end;
 677                         }
 678
 679                         break;
 680
 681                 case CLOCK_EXPECTATION_ORIGIN_UNIX:
 682                         if (!clock_class) {
 683                                 BT_ASSERT_COND_DEV_MSG(
 684                                         "Expecting a clock class, got none.");
 685                                 result = false;
 686                                 goto end;
 687                         }
 688
 689                         if (!bt_clock_class_origin_is_unix_epoch(clock_class)) {
 690                                 BT_ASSERT_COND_DEV_MSG(
 691                                         "Expecting a clock class with Unix epoch origin: %![cc-]+K",
 692                                         clock_class);
 693                                 result = false;
 694                                 goto end;
 695                         }
 696                         break;
 697
 698                 case CLOCK_EXPECTATION_ORIGIN_OTHER_UUID:
 699                         if (!clock_class) {
 700                                 BT_ASSERT_COND_DEV_MSG(
 701                                         "Expecting a clock class, got none.");
 702                                 result = false;
 703                                 goto end;
 704                         }
 705
 706                         if (bt_clock_class_origin_is_unix_epoch(clock_class)) {
 707                                 BT_ASSERT_COND_DEV_MSG(
 708                                         "Expecting a clock class without Unix epoch origin: %![cc-]+K",
 709                                         clock_class);
 710                                 result = false;
 711                                 goto end;
 712                         }
 713
 714                         if (!clock_class_uuid) {
 715                                 BT_ASSERT_COND_DEV_MSG(
 716                                         "Expecting a clock class with UUID: %![cc-]+K",
 717                                         clock_class);
 718                                 result = false;
 719                                 goto end;
 720                         }
 721
 722                         if (bt_uuid_compare(iterator->clock_expectation.uuid, clock_class_uuid)) {
 723                                 BT_ASSERT_COND_DEV_MSG(
 724                                         "Expecting a clock class with UUID, got one "
 725                                         "with a different UUID: %![cc-]+K, expected-uuid=%!u",
 726                                         clock_class, iterator->clock_expectation.uuid);
 727                                 result = false;
 728                                 goto end;
 729                         }
 730                         break;
 731
 732                 case CLOCK_EXPECTATION_ORIGIN_OTHER_NO_UUID:
 733                         if (!clock_class) {
 734                                 BT_ASSERT_COND_DEV_MSG(
 735                                         "Expecting a clock class, got none.");
 736                                 result = false;
 737                                 goto end;
 738                         }
 739
 740                         if (bt_clock_class_origin_is_unix_epoch(clock_class)) {
 741                                 BT_ASSERT_COND_DEV_MSG(
 742                                         "Expecting a clock class without Unix epoch origin: %![cc-]+K",
 743                                         clock_class);
 744                                 result = false;
 745                                 goto end;
 746                         }
 747
 748                         if (clock_class_uuid) {
 749                                 BT_ASSERT_COND_DEV_MSG(
 750                                         "Expecting a clock class without UUID: %![cc-]+K",
 751                                         clock_class);
 752                                 result = false;
 753                                 goto end;
 754                         }
 755                         break;
 756                 }
 757         }
 758
 759         result = true;
 760
 761 end:
 762         return result;
 763 }
 764
 765 BT_ASSERT_COND_DEV_FUNC
 766 static
 767 bool clock_classes_are_compatible(
 768                 struct bt_message_iterator *iterator,
 769                 bt_message_array_const msgs, uint64_t msg_count)
 770 {
 771         uint64_t i;
 772         bool result;
 773
 774         for (i = 0; i < msg_count; i++) {
 775                 if (!clock_classes_are_compatible_one(iterator, msgs[i])) {
 776                         result = false;
 777                         goto end;
 778                 }
 779         }
 780
 781         result = true;
 782
 783 end:
 784         return result;
 785 }
 786
 787 /*
 788  * Call the `next` method of the iterator.  Do some validation on the returned
 789  * messages.
 790  */
 791
 792 #define NEXT_METHOD_NAME        "bt_message_iterator_class_next_method"
 793
 794 static
 795 enum bt_message_iterator_class_next_method_status
 796 call_iterator_next_method(
 797                 struct bt_message_iterator *iterator,
 798                 bt_message_array_const msgs, uint64_t capacity, uint64_t *user_count)
 799 {
 800         enum bt_message_iterator_class_next_method_status status;
 801
 802         BT_ASSERT_DBG(iterator->methods.next);
 803         BT_LOGD_STR("Calling user's \"next\" method.");
 804         status = iterator->methods.next(iterator, msgs, capacity, user_count);
 805         BT_LOGD("User method returned: status=%s, msg-count=%" PRIu64,
 806                 bt_common_func_status_string(status), *user_count);
 807
 808         if (status == BT_FUNC_STATUS_OK) {
 809                 BT_ASSERT_POST_DEV(NEXT_METHOD_NAME,
 810                         "message-clock-classes-are-compatible",
 811                         clock_classes_are_compatible(iterator, msgs,
 812                                 *user_count),
 813                         "Clocks are not compatible");
 814                 BT_ASSERT_POST_DEV(NEXT_METHOD_NAME,
 815                         "message-clock-snapshots-are-monotonic",
 816                         clock_snapshots_are_monotonic(iterator, msgs,
 817                                 *user_count),
 818                         "Clock snapshots are not monotonic");
 819         }
 820
 821         BT_ASSERT_POST_DEV_NO_ERROR_IF_NO_ERROR_STATUS(NEXT_METHOD_NAME,
 822                 status);
 823
 824         return status;
 825 }
 826
 827 enum bt_message_iterator_next_status
 828 bt_message_iterator_next(
 829                 struct bt_message_iterator *iterator,
 830                 bt_message_array_const *msgs, uint64_t *user_count)
 831 {
 832         enum bt_message_iterator_next_status status = BT_FUNC_STATUS_OK;
 833
 834         BT_ASSERT_PRE_DEV_NO_ERROR();
 835         BT_ASSERT_PRE_DEV_MSG_ITER_NON_NULL(iterator);
 836         BT_ASSERT_PRE_DEV_NON_NULL("message-array-output", msgs,
 837                 "Message array (output)");
 838         BT_ASSERT_PRE_DEV_NON_NULL("user-count-output", user_count,
 839                 "Message count (output)");
 840         BT_ASSERT_PRE_DEV("message-iterator-is-active",
 841                 iterator->state == BT_MESSAGE_ITERATOR_STATE_ACTIVE,
 842                 "Message iterator's \"next\" called, but "
 843                 "message iterator is in the wrong state: %!+i", iterator);
 844         BT_ASSERT_DBG(iterator->upstream_component);
 845         BT_ASSERT_DBG(iterator->upstream_component->class);
 846         BT_ASSERT_PRE_DEV("graph-is-configured",
 847                 bt_component_borrow_graph(iterator->upstream_component)->config_state !=
 848                         BT_GRAPH_CONFIGURATION_STATE_CONFIGURING,
 849                 "Graph is not configured: %!+g",
 850                 bt_component_borrow_graph(iterator->upstream_component));
 851         BT_LIB_LOGD("Getting next self component input port "
 852                 "message iterator's messages: %!+i, batch-size=%u",
 853                 iterator, MSG_BATCH_SIZE);
 854
 855         /*
 856          * Call the user's "next" method to get the next messages
 857          * and status.
 858          */
 859         *user_count = 0;
 860         status = (int) call_iterator_next_method(iterator,
 861                 (void *) iterator->msgs->pdata, MSG_BATCH_SIZE,
 862                 user_count);
 863         BT_LOGD("User method returned: status=%s, msg-count=%" PRIu64,
 864                 bt_common_func_status_string(status), *user_count);
 865         if (status < 0) {
 866                 BT_LIB_LOGW_APPEND_CAUSE(
 867                         "Component input port message iterator's \"next\" method failed: "
 868                         "%![iter-]+i, status=%s",
 869                         iterator, bt_common_func_status_string(status));
 870                 goto end;
 871         }
 872
 873         /*
 874          * There is no way that this iterator could have been finalized
 875          * during its "next" method, as the only way to do this is to
 876          * put the last iterator's reference, and this can only be done
 877          * by its downstream owner.
 878          *
 879          * For the same reason, there is no way that this iterator could
 880          * have seeked (cannot seek a self message iterator).
 881          */
 882         BT_ASSERT_DBG(iterator->state ==
 883                 BT_MESSAGE_ITERATOR_STATE_ACTIVE);
 884
 885         switch (status) {
 886         case BT_FUNC_STATUS_OK:
 887                 BT_ASSERT_POST_DEV(NEXT_METHOD_NAME, "count-lteq-capacity",
 888                         *user_count <= MSG_BATCH_SIZE,
 889                         "Invalid returned message count: greater than "
 890                         "batch size: count=%" PRIu64 ", batch-size=%u",
 891                         *user_count, MSG_BATCH_SIZE);
 892                 *msgs = (void *) iterator->msgs->pdata;
 893                 break;
 894         case BT_FUNC_STATUS_AGAIN:
 895                 goto end;
 896         case BT_FUNC_STATUS_END:
 897                 set_msg_iterator_state(iterator,
 898                         BT_MESSAGE_ITERATOR_STATE_ENDED);
 899                 goto end;
 900         default:
 901                 /* Unknown non-error status */
 902                 bt_common_abort();
 903         }
 904
 905 end:
 906         return status;
 907 }
 908
 909 struct bt_component *
 910 bt_message_iterator_borrow_component(
 911                 struct bt_message_iterator *iterator)
 912 {
 913         BT_ASSERT_PRE_DEV_MSG_ITER_NON_NULL(iterator);
 914         return iterator->upstream_component;
 915 }
 916
 917 struct bt_self_component *bt_self_message_iterator_borrow_component(
 918                 struct bt_self_message_iterator *self_iterator)
 919 {
 920         struct bt_message_iterator *iterator =
 921                 (void *) self_iterator;
 922
 923         BT_ASSERT_PRE_DEV_MSG_ITER_NON_NULL(iterator);
 924         return (void *) iterator->upstream_component;
 925 }
 926
 927 struct bt_self_component_port_output *bt_self_message_iterator_borrow_port(
 928                 struct bt_self_message_iterator *self_iterator)
 929 {
 930         struct bt_message_iterator *iterator =
 931                 (void *) self_iterator;
 932
 933         BT_ASSERT_PRE_DEV_MSG_ITER_NON_NULL(iterator);
 934         return (void *) iterator->upstream_port;
 935 }
 936
 937 #define CAN_SEEK_NS_FROM_ORIGIN_METHOD_NAME                             \
 938         "bt_message_iterator_class_can_seek_ns_from_origin_method"
 939
 940 enum bt_message_iterator_can_seek_ns_from_origin_status
 941 bt_message_iterator_can_seek_ns_from_origin(
 942                 struct bt_message_iterator *iterator,
 943                 int64_t ns_from_origin, bt_bool *can_seek)
 944 {
 945         enum bt_message_iterator_can_seek_ns_from_origin_status status;
 946
 947         BT_ASSERT_PRE_NO_ERROR();
 948         BT_ASSERT_PRE_MSG_ITER_NON_NULL(iterator);
 949         BT_ASSERT_PRE_RES_OUT_NON_NULL(can_seek);
 950         BT_ASSERT_PRE_ITER_HAS_STATE_TO_SEEK(iterator);
 951         BT_ASSERT_PRE("graph-is-configured",
 952                 bt_component_borrow_graph(iterator->upstream_component)->config_state !=
 953                         BT_GRAPH_CONFIGURATION_STATE_CONFIGURING,
 954                 "Graph is not configured: %!+g",
 955                 bt_component_borrow_graph(iterator->upstream_component));
 956
 957         if (iterator->methods.can_seek_ns_from_origin) {
 958                 /*
 959                  * Initialize to an invalid value, so we can post-assert that
 960                  * the method returned a valid value.
 961                  */
 962                 *can_seek = -1;
 963
 964                 BT_LIB_LOGD("Calling user's \"can seek nanoseconds from origin\" method: %!+i",
 965                         iterator);
 966
 967                 status = (int) iterator->methods.can_seek_ns_from_origin(iterator,
 968                         ns_from_origin, can_seek);
 969
 970                 BT_ASSERT_POST_NO_ERROR_IF_NO_ERROR_STATUS(
 971                         CAN_SEEK_NS_FROM_ORIGIN_METHOD_NAME, status);
 972
 973                 if (status != BT_FUNC_STATUS_OK) {
 974                         BT_LIB_LOGW_APPEND_CAUSE(
 975                                 "Component input port message iterator's \"can seek nanoseconds from origin\" method failed: "
 976                                 "%![iter-]+i, status=%s",
 977                                 iterator, bt_common_func_status_string(status));
 978                         goto end;
 979                 }
 980
 981                 BT_ASSERT_POST(CAN_SEEK_NS_FROM_ORIGIN_METHOD_NAME,
 982                         "valid-return-value",
 983                         *can_seek == BT_TRUE || *can_seek == BT_FALSE,
 984                         "Unexpected boolean value returned from user's \"can seek ns from origin\" method: val=%d, %![iter-]+i",
 985                         *can_seek, iterator);
 986
 987                 BT_LIB_LOGD(
 988                         "User's \"can seek nanoseconds from origin\" returned successfully: "
 989                         "%![iter-]+i, can-seek=%d",
 990                         iterator, *can_seek);
 991
 992                 if (*can_seek) {
 993                         goto end;
 994                 }
 995         }
 996
 997         /*
 998          * Automatic seeking fall back: if we can seek to the beginning and the
 999          * iterator supports forward seeking then we can automatically seek to
1000          * any timestamp.
1001          */
1002         status = (int) bt_message_iterator_can_seek_beginning(
1003                 iterator, can_seek);
1004         if (status != BT_FUNC_STATUS_OK) {
1005                 goto end;
1006         }
1007
1008         *can_seek = *can_seek && iterator->config.can_seek_forward;
1009
1010 end:
1011         return status;
1012 }
1013
1014 #define CAN_SEEK_BEGINNING_METHOD_NAME                                  \
1015         "bt_message_iterator_class_can_seek_beginning"
1016
1017 enum bt_message_iterator_can_seek_beginning_status
1018 bt_message_iterator_can_seek_beginning(
1019                 struct bt_message_iterator *iterator,
1020                 bt_bool *can_seek)
1021 {
1022         enum bt_message_iterator_can_seek_beginning_status status;
1023
1024         BT_ASSERT_PRE_NO_ERROR();
1025         BT_ASSERT_PRE_MSG_ITER_NON_NULL(iterator);
1026         BT_ASSERT_PRE_RES_OUT_NON_NULL(can_seek);
1027         BT_ASSERT_PRE_ITER_HAS_STATE_TO_SEEK(iterator);
1028         BT_ASSERT_PRE("graph-is-configured",
1029                 bt_component_borrow_graph(iterator->upstream_component)->config_state !=
1030                         BT_GRAPH_CONFIGURATION_STATE_CONFIGURING,
1031                 "Graph is not configured: %!+g",
1032                 bt_component_borrow_graph(iterator->upstream_component));
1033
1034         if (iterator->methods.can_seek_beginning) {
1035                 /*
1036                  * Initialize to an invalid value, so we can post-assert that
1037                  * the method returned a valid value.
1038                  */
1039                 *can_seek = -1;
1040
1041                 status = (int) iterator->methods.can_seek_beginning(iterator, can_seek);
1042
1043                 BT_ASSERT_POST(CAN_SEEK_BEGINNING_METHOD_NAME,
1044                         "valid-return-value",
1045                         status != BT_FUNC_STATUS_OK ||
1046                                 *can_seek == BT_TRUE ||
1047                                 *can_seek == BT_FALSE,
1048                         "Unexpected boolean value returned from user's \"can seek beginning\" method: val=%d, %![iter-]+i",
1049                         *can_seek, iterator);
1050                 BT_ASSERT_POST_NO_ERROR_IF_NO_ERROR_STATUS(
1051                         CAN_SEEK_BEGINNING_METHOD_NAME, status);
1052         } else {
1053                 *can_seek = BT_FALSE;
1054                 status = BT_FUNC_STATUS_OK;
1055         }
1056
1057         return status;
1058 }
1059
1060 static inline
1061 void set_iterator_state_after_seeking(
1062                 struct bt_message_iterator *iterator,
1063                 int status)
1064 {
1065         enum bt_message_iterator_state new_state = 0;
1066
1067         /* Set iterator's state depending on seeking status */
1068         switch (status) {
1069         case BT_FUNC_STATUS_OK:
1070                 new_state = BT_MESSAGE_ITERATOR_STATE_ACTIVE;
1071                 break;
1072         case BT_FUNC_STATUS_AGAIN:
1073                 new_state = BT_MESSAGE_ITERATOR_STATE_LAST_SEEKING_RETURNED_AGAIN;
1074                 break;
1075         case BT_FUNC_STATUS_ERROR:
1076         case BT_FUNC_STATUS_MEMORY_ERROR:
1077                 new_state = BT_MESSAGE_ITERATOR_STATE_LAST_SEEKING_RETURNED_ERROR;
1078                 break;
1079         case BT_FUNC_STATUS_END:
1080                 new_state = BT_MESSAGE_ITERATOR_STATE_ENDED;
1081                 break;
1082         default:
1083                 bt_common_abort();
1084         }
1085
1086         set_msg_iterator_state(iterator, new_state);
1087 }
1088
1089 static
1090 void reset_iterator_expectations(
1091                 struct bt_message_iterator *iterator)
1092 {
1093         iterator->last_ns_from_origin = INT64_MIN;
1094         iterator->clock_expectation.type = CLOCK_EXPECTATION_UNSET;
1095 }
1096
1097 static
1098 bool message_iterator_can_seek_beginning(
1099                 struct bt_message_iterator *iterator)
1100 {
1101         enum bt_message_iterator_can_seek_beginning_status status;
1102         bt_bool can_seek;
1103
1104         status = bt_message_iterator_can_seek_beginning(
1105                 iterator, &can_seek);
1106         if (status != BT_FUNC_STATUS_OK) {
1107                 can_seek = BT_FALSE;
1108         }
1109
1110         return can_seek;
1111 }
1112
1113 #define SEEK_BEGINNING_METHOD_NAME                                      \
1114         "bt_message_iterator_class_seek_beginning_method"
1115
1116 enum bt_message_iterator_seek_beginning_status
1117 bt_message_iterator_seek_beginning(struct bt_message_iterator *iterator)
1118 {
1119         int status;
1120
1121         BT_ASSERT_PRE_NO_ERROR();
1122         BT_ASSERT_PRE_MSG_ITER_NON_NULL(iterator);
1123         BT_ASSERT_PRE_ITER_HAS_STATE_TO_SEEK(iterator);
1124         BT_ASSERT_PRE("graph-is-configured",
1125                 bt_component_borrow_graph(iterator->upstream_component)->config_state !=
1126                         BT_GRAPH_CONFIGURATION_STATE_CONFIGURING,
1127                 "Graph is not configured: %!+g",
1128                 bt_component_borrow_graph(iterator->upstream_component));
1129         BT_ASSERT_PRE("can-seek-beginning",
1130                 message_iterator_can_seek_beginning(iterator),
1131                 "Message iterator cannot seek beginning: %!+i", iterator);
1132
1133         /*
1134          * We are seeking, reset our expectations about how the following
1135          * messages should look like.
1136          */
1137         reset_iterator_expectations(iterator);
1138
1139         BT_LIB_LOGD("Calling user's \"seek beginning\" method: %!+i", iterator);
1140         set_msg_iterator_state(iterator,
1141                 BT_MESSAGE_ITERATOR_STATE_SEEKING);
1142         status = iterator->methods.seek_beginning(iterator);
1143         BT_LOGD("User method returned: status=%s",
1144                 bt_common_func_status_string(status));
1145         BT_ASSERT_POST(SEEK_BEGINNING_METHOD_NAME, "valid-status",
1146                 status == BT_FUNC_STATUS_OK ||
1147                 status == BT_FUNC_STATUS_ERROR ||
1148                 status == BT_FUNC_STATUS_MEMORY_ERROR ||
1149                 status == BT_FUNC_STATUS_AGAIN,
1150                 "Unexpected status: %![iter-]+i, status=%s",
1151                 iterator, bt_common_func_status_string(status));
1152         BT_ASSERT_POST_NO_ERROR_IF_NO_ERROR_STATUS(SEEK_BEGINNING_METHOD_NAME,
1153                 status);
1154         if (status < 0) {
1155                 BT_LIB_LOGW_APPEND_CAUSE(
1156                         "Component input port message iterator's \"seek beginning\" method failed: "
1157                         "%![iter-]+i, status=%s",
1158                         iterator, bt_common_func_status_string(status));
1159         }
1160
1161         set_iterator_state_after_seeking(iterator, status);
1162         return status;
1163 }
1164
1165 bt_bool
1166 bt_message_iterator_can_seek_forward(
1167                 bt_message_iterator *iterator)
1168 {
1169         BT_ASSERT_PRE_MSG_ITER_NON_NULL(iterator);
1170
1171         return iterator->config.can_seek_forward;
1172 }
1173
1174 /*
1175  * Structure used to record the state of a given stream during the fast-forward
1176  * phase of an auto-seek.
1177  */
1178 struct auto_seek_stream_state {
1179         /*
1180          * Value representing which step of this timeline we are at.
1181          *
1182          *      time --->
1183          *   [SB]  1  [PB]  2  [PE]  1  [SE]
1184          *
1185          * At each point in the timeline, the messages we need to replicate are:
1186          *
1187          *   1: Stream beginning
1188          *   2: Stream beginning, packet beginning
1189          *
1190          * Before "Stream beginning" and after "Stream end", we don't need to
1191          * replicate anything as the stream doesn't exist.
1192          */
1193         enum {
1194                 AUTO_SEEK_STREAM_STATE_STREAM_BEGAN,
1195                 AUTO_SEEK_STREAM_STATE_PACKET_BEGAN,
1196         } state;
1197
1198         /*
1199          * If `state` is AUTO_SEEK_STREAM_STATE_PACKET_BEGAN, the packet we are
1200          * in.  This is a weak reference, since the packet will always be
1201          * alive by the time we use it.
1202          */
1203         struct bt_packet *packet;
1204
1205         /* Have we see a message with a clock snapshot yet? */
1206         bool seen_clock_snapshot;
1207 };
1208
1209 static
1210 struct auto_seek_stream_state *create_auto_seek_stream_state(void)
1211 {
1212         return g_new0(struct auto_seek_stream_state, 1);
1213 }
1214
1215 static
1216 void destroy_auto_seek_stream_state(void *ptr)
1217 {
1218         g_free(ptr);
1219 }
1220
1221 static
1222 GHashTable *create_auto_seek_stream_states(void)
1223 {
1224         return g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,
1225                 destroy_auto_seek_stream_state);
1226 }
1227
1228 static
1229 void destroy_auto_seek_stream_states(GHashTable *stream_states)
1230 {
1231         g_hash_table_destroy(stream_states);
1232 }
1233
1234 /*
1235  * Handle one message while we are in the fast-forward phase of an auto-seek.
1236  *
1237  * Sets `*got_first` to true if the message's timestamp is greater or equal to
1238  * `ns_from_origin`.  In other words, if this is the first message after our
1239  * seek point.
1240  *
1241  * `stream_states` is an hash table of `bt_stream *` (weak reference) to
1242  * `struct auto_seek_stream_state` used to keep the state of each stream
1243  * during the fast-forward.
1244  */
1245
1246 static inline
1247 int auto_seek_handle_message(
1248                 struct bt_message_iterator *iterator,
1249                 int64_t ns_from_origin, const struct bt_message *msg,
1250                 bool *got_first, GHashTable *stream_states)
1251 {
1252         int status = BT_FUNC_STATUS_OK;
1253         int64_t msg_ns_from_origin;
1254         const struct bt_clock_snapshot *clk_snapshot = NULL;
1255         int ret;
1256
1257         BT_ASSERT_DBG(msg);
1258         BT_ASSERT_DBG(got_first);
1259
1260         switch (msg->type) {
1261         case BT_MESSAGE_TYPE_EVENT:
1262         {
1263                 const struct bt_message_event *event_msg =
1264                         (const void *) msg;
1265
1266                 clk_snapshot = event_msg->default_cs;
1267                 BT_ASSERT_POST_DEV(NEXT_METHOD_NAME,
1268                         "event-message-has-default-clock-snapshot",
1269                         clk_snapshot,
1270                         "Event message has no default clock snapshot: %!+n",
1271                         event_msg);
1272                 break;
1273         }
1274         case BT_MESSAGE_TYPE_MESSAGE_ITERATOR_INACTIVITY:
1275         {
1276                 const struct bt_message_message_iterator_inactivity *inactivity_msg =
1277                         (const void *) msg;
1278
1279                 clk_snapshot = inactivity_msg->cs;
1280                 BT_ASSERT_DBG(clk_snapshot);
1281                 break;
1282         }
1283         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
1284         case BT_MESSAGE_TYPE_PACKET_END:
1285         {
1286                 const struct bt_message_packet *packet_msg =
1287                         (const void *) msg;
1288
1289                 clk_snapshot = packet_msg->default_cs;
1290                 BT_ASSERT_POST_DEV(NEXT_METHOD_NAME,
1291                         "packet-message-has-default-clock-snapshot",
1292                         clk_snapshot,
1293                         "Packet message has no default clock snapshot: %!+n",
1294                         packet_msg);
1295                 break;
1296         }
1297         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
1298         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
1299         {
1300                 struct bt_message_discarded_items *msg_disc_items =
1301                         (void *) msg;
1302
1303                 BT_ASSERT_POST_DEV(NEXT_METHOD_NAME,
1304                         "discarded-events-packets-message-has-default-clock-snapshot",
1305                         msg_disc_items->default_begin_cs &&
1306                                 msg_disc_items->default_end_cs,
1307                         "Discarded events/packets message has no default clock snapshots: %!+n",
1308                         msg_disc_items);
1309                 ret = bt_clock_snapshot_get_ns_from_origin(
1310                         msg_disc_items->default_begin_cs,
1311                         &msg_ns_from_origin);
1312                 if (ret) {
1313                         status = BT_FUNC_STATUS_ERROR;
1314                         goto end;
1315                 }
1316
1317                 if (msg_ns_from_origin >= ns_from_origin) {
1318                         *got_first = true;
1319                         goto push_msg;
1320                 }
1321
1322                 ret = bt_clock_snapshot_get_ns_from_origin(
1323                         msg_disc_items->default_end_cs,
1324                         &msg_ns_from_origin);
1325                 if (ret) {
1326                         status = BT_FUNC_STATUS_ERROR;
1327                         goto end;
1328                 }
1329
1330                 if (msg_ns_from_origin >= ns_from_origin) {
1331                         /*
1332                          * The discarded items message's beginning time
1333                          * is before the requested seeking time, but its
1334                          * end time is after. Modify the message so as
1335                          * to set its beginning time to the requested
1336                          * seeking time, and make its item count unknown
1337                          * as we don't know if items were really
1338                          * discarded within the new time range.
1339                          */
1340                         uint64_t new_begin_raw_value = 0;
1341
1342                         ret = bt_clock_class_clock_value_from_ns_from_origin(
1343                                 msg_disc_items->default_end_cs->clock_class,
1344                                 ns_from_origin, &new_begin_raw_value);
1345                         if (ret) {
1346                                 status = BT_FUNC_STATUS_ERROR;
1347                                 goto end;
1348                         }
1349
1350                         bt_clock_snapshot_set_raw_value(
1351                                 msg_disc_items->default_begin_cs,
1352                                 new_begin_raw_value);
1353                         msg_disc_items->count.base.avail =
1354                                 BT_PROPERTY_AVAILABILITY_NOT_AVAILABLE;
1355
1356                         /*
1357                          * It is safe to push it because its beginning
1358                          * time is exactly the requested seeking time.
1359                          */
1360                         goto push_msg;
1361                 } else {
1362                         goto skip_msg;
1363                 }
1364         }
1365         case BT_MESSAGE_TYPE_STREAM_BEGINNING:
1366         case BT_MESSAGE_TYPE_STREAM_END:
1367         {
1368                 struct bt_message_stream *stream_msg =
1369                         (struct bt_message_stream *) msg;
1370
1371                 if (stream_msg->default_cs_state != BT_MESSAGE_STREAM_CLOCK_SNAPSHOT_STATE_KNOWN) {
1372                         /* Ignore */
1373                         goto skip_msg;
1374                 }
1375
1376                 clk_snapshot = stream_msg->default_cs;
1377                 break;
1378         }
1379         default:
1380                 bt_common_abort();
1381         }
1382
1383         BT_ASSERT_DBG(clk_snapshot);
1384         ret = bt_clock_snapshot_get_ns_from_origin(clk_snapshot,
1385                 &msg_ns_from_origin);
1386         if (ret) {
1387                 status = BT_FUNC_STATUS_ERROR;
1388                 goto end;
1389         }
1390
1391         if (msg_ns_from_origin >= ns_from_origin) {
1392                 *got_first = true;
1393                 goto push_msg;
1394         }
1395
1396 skip_msg:
1397         /* This message won't be sent downstream. */
1398         switch (msg->type) {
1399         case BT_MESSAGE_TYPE_STREAM_BEGINNING:
1400         {
1401                 const struct bt_message_stream *stream_msg = (const void *) msg;
1402                 struct auto_seek_stream_state *stream_state;
1403
1404                 /* Update stream's state: stream began. */
1405                 stream_state = create_auto_seek_stream_state();
1406                 if (!stream_state) {
1407                         status = BT_FUNC_STATUS_MEMORY_ERROR;
1408                         goto end;
1409                 }
1410
1411                 stream_state->state = AUTO_SEEK_STREAM_STATE_STREAM_BEGAN;
1412
1413                 if (stream_msg->default_cs_state == BT_MESSAGE_STREAM_CLOCK_SNAPSHOT_STATE_KNOWN) {
1414                         stream_state->seen_clock_snapshot = true;
1415                 }
1416
1417                 BT_ASSERT_DBG(!bt_g_hash_table_contains(stream_states, stream_msg->stream));
1418                 g_hash_table_insert(stream_states, stream_msg->stream, stream_state);
1419                 break;
1420         }
1421         case BT_MESSAGE_TYPE_PACKET_BEGINNING:
1422         {
1423                 const struct bt_message_packet *packet_msg =
1424                         (const void *) msg;
1425                 struct auto_seek_stream_state *stream_state;
1426
1427                 /* Update stream's state: packet began. */
1428                 stream_state = g_hash_table_lookup(stream_states, packet_msg->packet->stream);
1429                 BT_ASSERT_DBG(stream_state);
1430                 BT_ASSERT_DBG(stream_state->state == AUTO_SEEK_STREAM_STATE_STREAM_BEGAN);
1431                 stream_state->state = AUTO_SEEK_STREAM_STATE_PACKET_BEGAN;
1432                 BT_ASSERT_DBG(!stream_state->packet);
1433                 stream_state->packet = packet_msg->packet;
1434
1435                 if (packet_msg->packet->stream->class->packets_have_beginning_default_clock_snapshot) {
1436                         stream_state->seen_clock_snapshot = true;
1437                 }
1438
1439                 break;
1440         }
1441         case BT_MESSAGE_TYPE_EVENT:
1442         {
1443                 const struct bt_message_event *event_msg = (const void *) msg;
1444                 struct auto_seek_stream_state *stream_state;
1445
1446                 stream_state = g_hash_table_lookup(stream_states,
1447                         event_msg->event->stream);
1448                 BT_ASSERT_DBG(stream_state);
1449
1450                 // HELPME: are we sure that event messages have clock snapshots at this point?
1451                 stream_state->seen_clock_snapshot = true;
1452
1453                 break;
1454         }
1455         case BT_MESSAGE_TYPE_PACKET_END:
1456         {
1457                 const struct bt_message_packet *packet_msg =
1458                         (const void *) msg;
1459                 struct auto_seek_stream_state *stream_state;
1460
1461                 /* Update stream's state: packet ended. */
1462                 stream_state = g_hash_table_lookup(stream_states, packet_msg->packet->stream);
1463                 BT_ASSERT_DBG(stream_state);
1464                 BT_ASSERT_DBG(stream_state->state == AUTO_SEEK_STREAM_STATE_PACKET_BEGAN);
1465                 stream_state->state = AUTO_SEEK_STREAM_STATE_STREAM_BEGAN;
1466                 BT_ASSERT_DBG(stream_state->packet);
1467                 stream_state->packet = NULL;
1468
1469                 if (packet_msg->packet->stream->class->packets_have_end_default_clock_snapshot) {
1470                         stream_state->seen_clock_snapshot = true;
1471                 }
1472
1473                 break;
1474         }
1475         case BT_MESSAGE_TYPE_STREAM_END:
1476         {
1477                 const struct bt_message_stream *stream_msg = (const void *) msg;
1478                 struct auto_seek_stream_state *stream_state;
1479
1480                 stream_state = g_hash_table_lookup(stream_states, stream_msg->stream);
1481                 BT_ASSERT_DBG(stream_state);
1482                 BT_ASSERT_DBG(stream_state->state == AUTO_SEEK_STREAM_STATE_STREAM_BEGAN);
1483                 BT_ASSERT_DBG(!stream_state->packet);
1484
1485                 /* Update stream's state: this stream doesn't exist anymore. */
1486                 g_hash_table_remove(stream_states, stream_msg->stream);
1487                 break;
1488         }
1489         case BT_MESSAGE_TYPE_DISCARDED_EVENTS:
1490         case BT_MESSAGE_TYPE_DISCARDED_PACKETS:
1491         {
1492                 const struct bt_message_discarded_items *discarded_msg =
1493                         (const void *) msg;
1494                 struct auto_seek_stream_state *stream_state;
1495
1496                 stream_state = g_hash_table_lookup(stream_states, discarded_msg->stream);
1497                 BT_ASSERT_DBG(stream_state);
1498
1499                 if ((msg->type == BT_MESSAGE_TYPE_DISCARDED_EVENTS && discarded_msg->stream->class->discarded_events_have_default_clock_snapshots) ||
1500                         (msg->type == BT_MESSAGE_TYPE_DISCARDED_PACKETS && discarded_msg->stream->class->discarded_packets_have_default_clock_snapshots)) {
1501                         stream_state->seen_clock_snapshot = true;
1502                 }
1503
1504                 break;
1505         }
1506         default:
1507                 break;
1508         }
1509
1510         bt_object_put_ref_no_null_check(msg);
1511         msg = NULL;
1512         goto end;
1513
1514 push_msg:
1515         g_queue_push_tail(iterator->auto_seek.msgs, (void *) msg);
1516         msg = NULL;
1517
1518 end:
1519         BT_ASSERT_DBG(!msg || status != BT_FUNC_STATUS_OK);
1520         return status;
1521 }
1522
1523 static
1524 int find_message_ge_ns_from_origin(
1525                 struct bt_message_iterator *iterator,
1526                 int64_t ns_from_origin, GHashTable *stream_states)
1527 {
1528         int status = BT_FUNC_STATUS_OK;
1529         enum bt_message_iterator_state init_state =
1530                 iterator->state;
1531         const struct bt_message *messages[MSG_BATCH_SIZE];
1532         uint64_t user_count = 0;
1533         uint64_t i;
1534         bool got_first = false;
1535
1536         BT_ASSERT_DBG(iterator);
1537         memset(&messages[0], 0, sizeof(messages[0]) * MSG_BATCH_SIZE);
1538
1539         /*
1540          * Make this iterator temporarily active (not seeking) to call
1541          * the "next" method.
1542          */
1543         set_msg_iterator_state(iterator,
1544                 BT_MESSAGE_ITERATOR_STATE_ACTIVE);
1545
1546         BT_ASSERT_DBG(iterator->methods.next);
1547
1548         while (!got_first) {
1549                 /*
1550                  * Call the user's "next" method to get the next
1551                  * messages and status.
1552                  */
1553                 status = call_iterator_next_method(iterator,
1554                         &messages[0], MSG_BATCH_SIZE, &user_count);
1555                 BT_LOGD("User method returned: status=%s",
1556                         bt_common_func_status_string(status));
1557                 if (status < 0) {
1558                         BT_LIB_LOGW_APPEND_CAUSE(
1559                                 "Component input port message iterator's \"next\" method failed: "
1560                                 "%![iter-]+i, status=%s",
1561                                 iterator, bt_common_func_status_string(status));
1562                 }
1563
1564                 /*
1565                  * The user's "next" method must not do any action which
1566                  * would change the iterator's state.
1567                  */
1568                 BT_ASSERT_DBG(iterator->state ==
1569                         BT_MESSAGE_ITERATOR_STATE_ACTIVE);
1570
1571                 switch (status) {
1572                 case BT_FUNC_STATUS_OK:
1573                         BT_ASSERT_POST_DEV(NEXT_METHOD_NAME,
1574                                 "count-lteq-capacity",
1575                                 user_count <= MSG_BATCH_SIZE,
1576                                 "Invalid returned message count: greater than "
1577                                 "batch size: count=%" PRIu64 ", batch-size=%u",
1578                                 user_count, MSG_BATCH_SIZE);
1579                         break;
1580                 case BT_FUNC_STATUS_AGAIN:
1581                 case BT_FUNC_STATUS_ERROR:
1582                 case BT_FUNC_STATUS_MEMORY_ERROR:
1583                 case BT_FUNC_STATUS_END:
1584                         goto end;
1585                 default:
1586                         bt_common_abort();
1587                 }
1588
1589                 for (i = 0; i < user_count; i++) {
1590                         if (got_first) {
1591                                 g_queue_push_tail(iterator->auto_seek.msgs,
1592                                         (void *) messages[i]);
1593                                 messages[i] = NULL;
1594                                 continue;
1595                         }
1596
1597                         status = auto_seek_handle_message(iterator,
1598                                 ns_from_origin, messages[i], &got_first,
1599                                 stream_states);
1600                         if (status == BT_FUNC_STATUS_OK) {
1601                                 /* Message was either pushed or moved */
1602                                 messages[i] = NULL;
1603                         } else {
1604                                 goto end;
1605                         }
1606                 }
1607         }
1608
1609 end:
1610         for (i = 0; i < user_count; i++) {
1611                 if (messages[i]) {
1612                         bt_object_put_ref_no_null_check(messages[i]);
1613                 }
1614         }
1615
1616         set_msg_iterator_state(iterator, init_state);
1617         return status;
1618 }
1619
1620 /*
1621  * This function is installed as the iterator's next callback after we have
1622  * auto-seeked (seeked to the beginning and fast-forwarded) to send the
1623  * messages saved in iterator->auto_seek.msgs.  Once this is done, the original
1624  * next callback is put back.
1625  */
1626
1627 static
1628 enum bt_message_iterator_class_next_method_status post_auto_seek_next(
1629                 struct bt_message_iterator *iterator,
1630                 bt_message_array_const msgs, uint64_t capacity,
1631                 uint64_t *count)
1632 {
1633         BT_ASSERT(!g_queue_is_empty(iterator->auto_seek.msgs));
1634         *count = 0;
1635
1636         /*
1637          * Move auto-seek messages to the output array (which is this
1638          * iterator's base message array).
1639          */
1640         while (capacity > 0 && !g_queue_is_empty(iterator->auto_seek.msgs)) {
1641                 msgs[*count] = g_queue_pop_head(iterator->auto_seek.msgs);
1642                 capacity--;
1643                 (*count)++;
1644         }
1645
1646         BT_ASSERT(*count > 0);
1647
1648         if (g_queue_is_empty(iterator->auto_seek.msgs)) {
1649                 /* No more auto-seek messages, restore user's next callback. */
1650                 BT_ASSERT(iterator->auto_seek.original_next_callback);
1651                 iterator->methods.next = iterator->auto_seek.original_next_callback;
1652                 iterator->auto_seek.original_next_callback = NULL;
1653         }
1654
1655         return BT_FUNC_STATUS_OK;
1656 }
1657
1658 static inline
1659 int clock_raw_value_from_ns_from_origin(const bt_clock_class *clock_class,
1660                 int64_t ns_from_origin, uint64_t *raw_value)
1661 {
1662
1663         int64_t cc_offset_s = clock_class->offset_seconds;
1664         uint64_t cc_offset_cycles = clock_class->offset_cycles;
1665         uint64_t cc_freq = clock_class->frequency;
1666
1667         return bt_common_clock_value_from_ns_from_origin(cc_offset_s,
1668                 cc_offset_cycles, cc_freq, ns_from_origin, raw_value);
1669 }
1670
1671 static
1672 bool message_iterator_can_seek_ns_from_origin(
1673                 struct bt_message_iterator *iterator,
1674                 int64_t ns_from_origin)
1675 {
1676         enum bt_message_iterator_can_seek_ns_from_origin_status status;
1677         bt_bool can_seek;
1678
1679         status = bt_message_iterator_can_seek_ns_from_origin(
1680                 iterator, ns_from_origin, &can_seek);
1681         if (status != BT_FUNC_STATUS_OK) {
1682                 can_seek = BT_FALSE;
1683         }
1684
1685         return can_seek;
1686 }
1687
1688 #define SEEK_NS_FROM_ORIGIN_METHOD_NAME                                 \
1689         "bt_message_iterator_class_seek_ns_from_origin_method"
1690
1691
1692 enum bt_message_iterator_seek_ns_from_origin_status
1693 bt_message_iterator_seek_ns_from_origin(
1694                 struct bt_message_iterator *iterator,
1695                 int64_t ns_from_origin)
1696 {
1697         int status;
1698         GHashTable *stream_states = NULL;
1699         bt_bool can_seek_by_itself;
1700
1701         BT_ASSERT_PRE_NO_ERROR();
1702         BT_ASSERT_PRE_MSG_ITER_NON_NULL(iterator);
1703         BT_ASSERT_PRE_ITER_HAS_STATE_TO_SEEK(iterator);
1704         BT_ASSERT_PRE("graph-is-configured",
1705                 bt_component_borrow_graph(iterator->upstream_component)->config_state !=
1706                         BT_GRAPH_CONFIGURATION_STATE_CONFIGURING,
1707                 "Graph is not configured: %!+g",
1708                 bt_component_borrow_graph(iterator->upstream_component));
1709         /* The iterator must be able to seek ns from origin one way or another. */
1710         BT_ASSERT_PRE("can-seek-ns-from-origin",
1711                 message_iterator_can_seek_ns_from_origin(iterator, ns_from_origin),
1712                 "Message iterator cannot seek nanoseconds from origin: %!+i, "
1713                 "ns-from-origin=%" PRId64, iterator, ns_from_origin);
1714         set_msg_iterator_state(iterator,
1715                 BT_MESSAGE_ITERATOR_STATE_SEEKING);
1716
1717         /*
1718          * We are seeking, reset our expectations about how the following
1719          * messages should look like.
1720          */
1721         reset_iterator_expectations(iterator);
1722
1723         /* Check if the iterator can seek by itself.  If not we'll use autoseek. */
1724         if (iterator->methods.can_seek_ns_from_origin) {
1725                 bt_message_iterator_class_can_seek_ns_from_origin_method_status
1726                         can_seek_status;
1727
1728                 can_seek_status =
1729                         iterator->methods.can_seek_ns_from_origin(
1730                                 iterator, ns_from_origin, &can_seek_by_itself);
1731                 if (can_seek_status != BT_FUNC_STATUS_OK) {
1732                         status = can_seek_status;
1733                         goto end;
1734                 }
1735         } else {
1736                 can_seek_by_itself = false;
1737         }
1738
1739         if (can_seek_by_itself) {
1740                 /* The iterator knows how to seek to a particular time, let it handle this. */
1741                 BT_ASSERT(iterator->methods.seek_ns_from_origin);
1742                 BT_LIB_LOGD("Calling user's \"seek nanoseconds from origin\" method: "
1743                         "%![iter-]+i, ns=%" PRId64, iterator, ns_from_origin);
1744                 status = iterator->methods.seek_ns_from_origin(iterator,
1745                         ns_from_origin);
1746                 BT_LOGD("User method returned: status=%s",
1747                         bt_common_func_status_string(status));
1748                 BT_ASSERT_POST(SEEK_NS_FROM_ORIGIN_METHOD_NAME, "valid-status",
1749                         status == BT_FUNC_STATUS_OK ||
1750                         status == BT_FUNC_STATUS_ERROR ||
1751                         status == BT_FUNC_STATUS_MEMORY_ERROR ||
1752                         status == BT_FUNC_STATUS_AGAIN,
1753                         "Unexpected status: %![iter-]+i, status=%s",
1754                         iterator, bt_common_func_status_string(status));
1755                 BT_ASSERT_POST_NO_ERROR_IF_NO_ERROR_STATUS(
1756                         SEEK_NS_FROM_ORIGIN_METHOD_NAME, status);
1757                 if (status < 0) {
1758                         BT_LIB_LOGW_APPEND_CAUSE(
1759                                 "Component input port message iterator's \"seek nanoseconds from origin\" method failed: "
1760                                 "%![iter-]+i, status=%s",
1761                                 iterator, bt_common_func_status_string(status));
1762                 }
1763         } else {
1764                 /*
1765                  * The iterator doesn't know how to seek by itself to a
1766                  * particular time.  We will seek to the beginning and fast
1767                  * forward to the right place.
1768                  */
1769                 enum bt_message_iterator_class_can_seek_beginning_method_status can_seek_status;
1770                 bt_bool can_seek_beginning;
1771
1772                 can_seek_status = iterator->methods.can_seek_beginning(iterator,
1773                         &can_seek_beginning);
1774                 BT_ASSERT(can_seek_status == BT_FUNC_STATUS_OK);
1775                 BT_ASSERT(can_seek_beginning);
1776                 BT_ASSERT(iterator->methods.seek_beginning);
1777                 BT_LIB_LOGD("Calling user's \"seek beginning\" method: %!+i",
1778                         iterator);
1779                 status = iterator->methods.seek_beginning(iterator);
1780                 BT_LOGD("User method returned: status=%s",
1781                         bt_common_func_status_string(status));
1782                 BT_ASSERT_POST(SEEK_BEGINNING_METHOD_NAME, "valid-status",
1783                         status == BT_FUNC_STATUS_OK ||
1784                         status == BT_FUNC_STATUS_ERROR ||
1785                         status == BT_FUNC_STATUS_MEMORY_ERROR ||
1786                         status == BT_FUNC_STATUS_AGAIN,
1787                         "Unexpected status: %![iter-]+i, status=%s",
1788                         iterator, bt_common_func_status_string(status));
1789                 if (status < 0) {
1790                         BT_LIB_LOGW_APPEND_CAUSE(
1791                                 "Component input port message iterator's \"seek beginning\" method failed: "
1792                                 "%![iter-]+i, status=%s",
1793                                 iterator, bt_common_func_status_string(status));
1794                 }
1795
1796                 switch (status) {
1797                 case BT_FUNC_STATUS_OK:
1798                         break;
1799                 case BT_FUNC_STATUS_ERROR:
1800                 case BT_FUNC_STATUS_MEMORY_ERROR:
1801                 case BT_FUNC_STATUS_AGAIN:
1802                         goto end;
1803                 default:
1804                         bt_common_abort();
1805                 }
1806
1807                 /*
1808                  * Find the first message which has a default clock
1809                  * snapshot greater than or equal to the requested
1810                  * seeking time, and move the received messages from
1811                  * this point in the batch to this iterator's auto-seek
1812                  * message queue.
1813                  */
1814                 while (!g_queue_is_empty(iterator->auto_seek.msgs)) {
1815                         bt_object_put_ref_no_null_check(
1816                                 g_queue_pop_tail(iterator->auto_seek.msgs));
1817                 }
1818
1819                 stream_states = create_auto_seek_stream_states();
1820                 if (!stream_states) {
1821                         BT_LIB_LOGE_APPEND_CAUSE(
1822                                 "Failed to allocate one GHashTable.");
1823                         status = BT_FUNC_STATUS_MEMORY_ERROR;
1824                         goto end;
1825                 }
1826
1827                 status = find_message_ge_ns_from_origin(iterator,
1828                         ns_from_origin, stream_states);
1829                 switch (status) {
1830                 case BT_FUNC_STATUS_OK:
1831                 case BT_FUNC_STATUS_END:
1832                 {
1833                         GHashTableIter iter;
1834                         gpointer key, value;
1835
1836                         /*
1837                          * If some streams exist at the seek time, prepend the
1838                          * required messages to put those streams in the right
1839                          * state.
1840                          */
1841                         g_hash_table_iter_init(&iter, stream_states);
1842                         while (g_hash_table_iter_next (&iter, &key, &value)) {
1843                                 const bt_stream *stream = key;
1844                                 struct auto_seek_stream_state *stream_state =
1845                                         (struct auto_seek_stream_state *) value;
1846                                 bt_message *msg;
1847                                 const bt_clock_class *clock_class = bt_stream_class_borrow_default_clock_class_const(
1848                                         bt_stream_borrow_class_const(stream));
1849                                 /* Initialize to silence maybe-uninitialized warning. */
1850                                 uint64_t raw_value = 0;
1851
1852                                 /*
1853                                  * If we haven't seen a message with a clock snapshot, we don't know if our seek time is within
1854                                  * the clock's range, so it wouldn't be safe to try to convert ns_from_origin to a clock value.
1855                                  *
1856                                  * Also, it would be a bit of a lie to generate a stream begin message with the seek time as its
1857                                  * clock snapshot, because we don't really know if the stream existed at that time.  If we have
1858                                  * seen a message with a clock snapshot in our seeking, then we are sure that the
1859                                  * seek time is not below the clock range, and we know the stream was active at that
1860                                  * time (and that we cut it short).
1861                                  */
1862                                 if (stream_state->seen_clock_snapshot) {
1863                                         if (clock_raw_value_from_ns_from_origin(clock_class, ns_from_origin, &raw_value) != 0) {
1864                                                 BT_LIB_LOGW("Could not convert nanoseconds from origin to clock value: ns-from-origin=%" PRId64 ", %![cc-]+K",
1865                                                         ns_from_origin, clock_class);
1866                                                 status = BT_FUNC_STATUS_ERROR;
1867                                                 goto end;
1868                                         }
1869                                 }
1870
1871                                 switch (stream_state->state) {
1872                                 case AUTO_SEEK_STREAM_STATE_PACKET_BEGAN:
1873                                         BT_ASSERT(stream_state->packet);
1874                                         BT_LIB_LOGD("Creating packet message: %![packet-]+a", stream_state->packet);
1875
1876                                         if (stream->class->packets_have_beginning_default_clock_snapshot) {
1877                                                 /*
1878                                                  * If we are in the PACKET_BEGAN state, it means we have seen a "packet beginning"
1879                                                  * message.  If "packet beginning" packets have clock snapshots, then we must have
1880                                                  * seen a clock snapshot.
1881                                                  */
1882                                                 BT_ASSERT(stream_state->seen_clock_snapshot);
1883
1884                                                 msg = bt_message_packet_beginning_create_with_default_clock_snapshot(
1885                                                         (bt_self_message_iterator *) iterator, stream_state->packet, raw_value);
1886                                         } else {
1887                                                 msg = bt_message_packet_beginning_create((bt_self_message_iterator *) iterator,
1888                                                                 stream_state->packet);
1889                                         }
1890
1891                                         if (!msg) {
1892                                                 status = BT_FUNC_STATUS_MEMORY_ERROR;
1893                                                 goto end;
1894                                         }
1895
1896                                         g_queue_push_head(iterator->auto_seek.msgs, msg);
1897                                         msg = NULL;
1898                                         /* fall-thru */
1899
1900                                 case AUTO_SEEK_STREAM_STATE_STREAM_BEGAN:
1901                                         msg = bt_message_stream_beginning_create(
1902                                                 (bt_self_message_iterator *) iterator, stream);
1903                                         if (!msg) {
1904                                                 status = BT_FUNC_STATUS_MEMORY_ERROR;
1905                                                 goto end;
1906                                         }
1907
1908                                         if (stream_state->seen_clock_snapshot) {
1909                                                 bt_message_stream_beginning_set_default_clock_snapshot(msg, raw_value);
1910                                         }
1911
1912                                         g_queue_push_head(iterator->auto_seek.msgs, msg);
1913                                         msg = NULL;
1914                                         break;
1915                                 }
1916                         }
1917
1918                         /*
1919                          * If there are messages in the auto-seek
1920                          * message queue, replace the user's "next"
1921                          * method with a custom, temporary "next" method
1922                          * which returns them.
1923                          */
1924                         if (!g_queue_is_empty(iterator->auto_seek.msgs)) {
1925                                 BT_ASSERT(!iterator->auto_seek.original_next_callback);
1926                                 iterator->auto_seek.original_next_callback = iterator->methods.next;
1927
1928                                 iterator->methods.next =
1929                                         (bt_message_iterator_next_method)
1930                                                 post_auto_seek_next;
1931                         }
1932
1933                         /*
1934                          * `BT_FUNC_STATUS_END` becomes
1935                          * `BT_FUNC_STATUS_OK`: the next
1936                          * time this iterator's "next" method is called,
1937                          * it will return
1938                          * `BT_FUNC_STATUS_END`.
1939                          */
1940                         status = BT_FUNC_STATUS_OK;
1941                         break;
1942                 }
1943                 case BT_FUNC_STATUS_ERROR:
1944                 case BT_FUNC_STATUS_MEMORY_ERROR:
1945                 case BT_FUNC_STATUS_AGAIN:
1946                         goto end;
1947                 default:
1948                         bt_common_abort();
1949                 }
1950         }
1951
1952         /*
1953          * The following messages returned by the next method (including
1954          * post_auto_seek_next) must be after (or at) `ns_from_origin`.
1955          */
1956         iterator->last_ns_from_origin = ns_from_origin;
1957
1958 end:
1959         if (stream_states) {
1960                 destroy_auto_seek_stream_states(stream_states);
1961                 stream_states = NULL;
1962         }
1963
1964         set_iterator_state_after_seeking(iterator, status);
1965         return status;
1966 }
1967
1968 bt_bool bt_self_message_iterator_is_interrupted(
1969                 const struct bt_self_message_iterator *self_msg_iter)
1970 {
1971         const struct bt_message_iterator *iterator =
1972                 (const void *) self_msg_iter;
1973
1974         BT_ASSERT_PRE_MSG_ITER_NON_NULL(iterator);
1975         return (bt_bool) bt_graph_is_interrupted(iterator->graph);
1976 }
1977
1978 void bt_message_iterator_get_ref(
1979                 const struct bt_message_iterator *iterator)
1980 {
1981         bt_object_get_ref(iterator);
1982 }
1983
1984 void bt_message_iterator_put_ref(
1985                 const struct bt_message_iterator *iterator)
1986 {
1987         bt_object_put_ref(iterator);
1988 }