iterator: move auto-seek data in its own struct, add comments

Further patches will add more fields related to this feature, so it
seems useful to group them under the same (anonymous) struct.

No functional changes intended.

Change-Id: I6ed922801cf5bd9001d388d7d8b050a6c8d01790
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>
Reviewed-on: https://review.lttng.org/c/babeltrace/+/1484
Tested-by: jenkins <jenkins@lttng.org>
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>

diff --git a/src/lib/graph/iterator.c b/src/lib/graph/iterator.c
index b6117e125c05b36110ca7db4921fffefd1d64e6c..6fd22af01d5695219493c218a85e4760ee4838ab 100644 (file)
--- a/src/lib/graph/iterator.c
+++ b/src/lib/graph/iterator.c
@@ -144,14 +144,14 @@ void bt_self_component_port_input_message_iterator_destroy(struct bt_object *obj
                iterator->connection = NULL;
        }
 
-       if (iterator->auto_seek_msgs) {
-               while (!g_queue_is_empty(iterator->auto_seek_msgs)) {
+       if (iterator->auto_seek.msgs) {
+               while (!g_queue_is_empty(iterator->auto_seek.msgs)) {
                        bt_object_put_no_null_check(
-                               g_queue_pop_tail(iterator->auto_seek_msgs));
+                               g_queue_pop_tail(iterator->auto_seek.msgs));
                }
 
-               g_queue_free(iterator->auto_seek_msgs);
-               iterator->auto_seek_msgs = NULL;
+               g_queue_free(iterator->auto_seek.msgs);
+               iterator->auto_seek.msgs = NULL;
        }
 
        destroy_base_message_iterator(obj);
@@ -316,8 +316,8 @@ bt_self_component_port_input_message_iterator_create_initial(
                goto end;
        }
 
-       iterator->auto_seek_msgs = g_queue_new();
-       if (!iterator->auto_seek_msgs) {
+       iterator->auto_seek.msgs = g_queue_new();
+       if (!iterator->auto_seek.msgs) {
                BT_LOGE_STR("Failed to allocate a GQueue.");
                ret = -1;
                goto end;
@@ -1141,7 +1141,7 @@ skip_msg:
        goto end;
 
 push_msg:
-       g_queue_push_tail(iterator->auto_seek_msgs, (void *) msg);
+       g_queue_push_tail(iterator->auto_seek.msgs, (void *) msg);
        msg = NULL;
 
 end:
@@ -1210,7 +1210,7 @@ enum bt_message_iterator_status find_message_ge_ns_from_origin(
 
                for (i = 0; i < user_count; i++) {
                        if (got_first) {
-                               g_queue_push_tail(iterator->auto_seek_msgs,
+                               g_queue_push_tail(iterator->auto_seek.msgs,
                                        (void *) messages[i]);
                                messages[i] = NULL;
                                continue;
@@ -1244,22 +1244,22 @@ enum bt_self_message_iterator_status post_auto_seek_next(
                bt_message_array_const msgs, uint64_t capacity,
                uint64_t *count)
 {
-       BT_ASSERT(!g_queue_is_empty(iterator->auto_seek_msgs));
+       BT_ASSERT(!g_queue_is_empty(iterator->auto_seek.msgs));
        *count = 0;
 
        /*
         * Move auto-seek messages to the output array (which is this
         * iterator's base message array).
         */
-       while (capacity > 0 && !g_queue_is_empty(iterator->auto_seek_msgs)) {
-               msgs[*count] = g_queue_pop_head(iterator->auto_seek_msgs);
+       while (capacity > 0 && !g_queue_is_empty(iterator->auto_seek.msgs)) {
+               msgs[*count] = g_queue_pop_head(iterator->auto_seek.msgs);
                capacity--;
                (*count)++;
        }
 
        BT_ASSERT(*count > 0);
 
-       if (g_queue_is_empty(iterator->auto_seek_msgs)) {
+       if (g_queue_is_empty(iterator->auto_seek.msgs)) {
                /* No more auto-seek messages */
                switch (iterator->upstream_component->class->type) {
                case BT_COMPONENT_CLASS_TYPE_SOURCE:
@@ -1360,9 +1360,9 @@ bt_self_component_port_input_message_iterator_seek_ns_from_origin(
                 * this point in the batch to this iterator's auto-seek
                 * message queue.
                 */
-               while (!g_queue_is_empty(iterator->auto_seek_msgs)) {
+               while (!g_queue_is_empty(iterator->auto_seek.msgs)) {
                        bt_object_put_no_null_check(
-                               g_queue_pop_tail(iterator->auto_seek_msgs));
+                               g_queue_pop_tail(iterator->auto_seek.msgs));
                }
 
                status = find_message_ge_ns_from_origin(iterator,
@@ -1376,7 +1376,7 @@ bt_self_component_port_input_message_iterator_seek_ns_from_origin(
                         * method with a custom, temporary "next" method
                         * which returns them.
                         */
-                       if (!g_queue_is_empty(iterator->auto_seek_msgs)) {
+                       if (!g_queue_is_empty(iterator->auto_seek.msgs)) {
                                iterator->methods.next =
                                        (bt_self_component_port_input_message_iterator_next_method)
                                                post_auto_seek_next;

diff --git a/src/lib/graph/message/iterator.h b/src/lib/graph/message/iterator.h
index 2c442a15db749f2ca4ff5610684806cf8b7d0b93..1ecaa95a991d29329a2816d1ffcc6dd0ca160bca 100644 (file)
--- a/src/lib/graph/message/iterator.h
+++ b/src/lib/graph/message/iterator.h
@@ -112,7 +112,27 @@ struct bt_self_component_port_input_message_iterator {
        } methods;
 
        enum bt_self_component_port_input_message_iterator_state state;
-       GQueue *auto_seek_msgs;
+
+       /*
+        * Data necessary for auto seek (the seek-to-beginning then fast-forward
+        * seek strategy).
+        */
+       struct {
+               /*
+                * Queue of `const bt_message *` (owned by this queue).
+                *
+                * When fast-forwarding, we get the messages from upstream in
+                * batches. Once we have found the first message with timestamp
+                * greater or equal to the seek time, we put it and all of the
+                * following message of the batch in this queue.  They will be
+                * sent on the next "next" call on this iterator.
+                *
+                * The messages are in chronological order (i.e. the first to
+                * send is the first of the queue).
+                */
+               GQueue *msgs;
+       } auto_seek;
+
        void *user_data;
 };