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gst/gstbin.c: Lame attempt at making the state change function a bit more readable.

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Original commit message from CVS:
* gst/gstbin.c: (clear_queue), (remove_all_from_queue),
(gst_bin_change_state):
Lame attempt at making the state change function a bit
more readable.
This commit is contained in:
Wim Taymans 2005-06-30 09:41:15 +00:00
parent 41b9a5264d
commit a578cfd009
2 changed files with 93 additions and 58 deletions
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8
ChangeLog
View file

@ -1,3 +1,11 @@
2005-06-30 Wim Taymans <wim@fluendo.com>
* gst/gstbin.c: (clear_queue), (remove_all_from_queue),
(gst_bin_change_state):
Probes are gone.
Lame attempt at making the state change function a bit
more readable.
2005-06-30 Wim Taymans <wim@fluendo.com>
* docs/design/part-clocks.txt:

143
gst/gstbin.c
View file

@ -1047,6 +1047,27 @@ gst_bin_iterate_state_order (GstBin * bin)
return result;
}
static void
clear_queue (GQueue * queue, gboolean unref)
{
gpointer p;
while ((p = g_queue_pop_head (queue)))
if (unref)
gst_object_unref (p);
}
static void
remove_all_from_queue (GQueue * queue, gpointer elem, gboolean unref)
{
gpointer p;
while ((p = g_queue_find (queue, elem))) {
if (unref)
gst_object_unref (elem);
g_queue_delete_link (queue, p);
}
}
/* this function is called with the STATE_LOCK held. It works
* as follows:
*
@ -1062,6 +1083,7 @@ gst_bin_iterate_state_order (GstBin * bin)
*
* MT safe.
*/
/* FIXME, make me more elegant */
static GstElementStateReturn
gst_bin_change_state (GstElement * element)
{
@ -1099,7 +1121,14 @@ gst_bin_change_state (GstElement * element)
/* first step, find all sink elements, these are the elements
* without (linked) source pads. */
GST_LOCK (bin);
restart:
/* make sure queues are empty, they could be filled when
* restarting. */
clear_queue (elem_queue, TRUE);
clear_queue (semi_queue, TRUE);
clear_queue (temp, TRUE);
children = bin->children;
children_cookie = bin->children_cookie;
while (children) {
@ -1117,30 +1146,25 @@ restart:
}
GST_LOCK (bin);
if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
/* undo what we had */
g_queue_foreach (elem_queue, (GFunc) gst_object_unref, NULL);
g_queue_foreach (semi_queue, (GFunc) gst_object_unref, NULL);
g_queue_foreach (temp, (GFunc) gst_object_unref, NULL);
while (g_queue_pop_head (elem_queue));
while (g_queue_pop_head (semi_queue));
while (g_queue_pop_head (temp));
if (G_UNLIKELY (children_cookie != bin->children_cookie))
goto restart;
}
children = g_list_next (children);
}
GST_UNLOCK (bin);
/* after this point new elements can be added/removed from the
* bin. We operate on the snapshot taken above. Applications
* should serialize their add/remove and set_state. */
/* now change state for semi sink elements first so add them in
* front of the other elements */
g_queue_foreach (temp, (GFunc) append_child, semi_queue);
g_queue_free (temp);
clear_queue (temp, FALSE);
/* can be the case for a bin like ( identity ) */
/* if we don't have real sinks, we continue with the other elements */
if (g_queue_is_empty (elem_queue) && !g_queue_is_empty (semi_queue)) {
GQueue *q = elem_queue;
/* we swap the queues as oposed to copy them over */
elem_queue = semi_queue;
semi_queue = q;
}
@ -1153,20 +1177,8 @@ restart:
/* take element */
qelement = g_queue_pop_head (elem_queue);
/* we don't need it in the semi_queue anymore */
g_queue_remove_all (semi_queue, qelement);
/* if queue is empty now, continue with a non-sink */
if (g_queue_is_empty (elem_queue)) {
GstElement *non_sink;
GST_DEBUG ("sinks and upstream elements exhausted");
non_sink = g_queue_pop_head (semi_queue);
if (non_sink) {
GST_DEBUG ("found lefover non-sink %s", GST_OBJECT_NAME (non_sink));
g_queue_push_tail (elem_queue, non_sink);
}
}
/* we don't need any duplicates in the other queue anymore */
remove_all_from_queue (semi_queue, qelement, TRUE);
/* queue all elements connected to the sinkpads of this element */
GST_LOCK (qelement);
@ -1189,31 +1201,24 @@ restart:
/* see if this element is in the bin we are currently handling */
parent = gst_object_get_parent (GST_OBJECT_CAST (peer_elem));
if (parent && parent == GST_OBJECT_CAST (bin)) {
GList *oldelem;
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"adding element %s to queue", GST_ELEMENT_NAME (peer_elem));
/* make sure we don't have duplicates */
while ((oldelem = g_queue_find (semi_queue, peer_elem))) {
gst_object_unref (peer_elem);
g_queue_delete_link (semi_queue, oldelem);
}
while ((oldelem = g_queue_find (elem_queue, peer_elem))) {
gst_object_unref (peer_elem);
g_queue_delete_link (elem_queue, oldelem);
}
/* was reffed before pushing on the queue by the
* gst_object_get_parent() call we used to get the element. */
g_queue_push_tail (elem_queue, peer_elem);
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"not adding element %s to queue, it is in another bin",
GST_ELEMENT_NAME (peer_elem));
gst_object_unref (peer_elem);
}
if (parent) {
if (parent == GST_OBJECT_CAST (bin)) {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"adding element %s to queue", GST_ELEMENT_NAME (peer_elem));
/* make sure we don't have duplicates */
remove_all_from_queue (semi_queue, peer_elem, TRUE);
remove_all_from_queue (elem_queue, peer_elem, TRUE);
/* was reffed before pushing on the queue by the
* gst_object_get_parent() call we used to get the element. */
g_queue_push_tail (elem_queue, peer_elem);
} else {
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"not adding element %s to queue, it is in another bin",
GST_ELEMENT_NAME (peer_elem));
gst_object_unref (peer_elem);
}
gst_object_unref (parent);
}
}
@ -1228,11 +1233,23 @@ restart:
locked = GST_FLAG_IS_SET (qelement, GST_ELEMENT_LOCKED_STATE);
GST_UNLOCK (qelement);
/* skip locked elements */
if (G_UNLIKELY (locked))
goto next_element;
/* set base time on element */
qelement->base_time = element->base_time;
ret = gst_element_set_state (qelement, pending);
/* the set state could have cause elements to be added/removed,
* we support that. */
GST_LOCK (bin);
if (G_UNLIKELY (children_cookie != bin->children_cookie)) {
gst_object_unref (qelement);
goto restart;
}
GST_UNLOCK (bin);
switch (ret) {
case GST_STATE_SUCCESS:
GST_CAT_DEBUG (GST_CAT_STATES,
@ -1268,6 +1285,18 @@ restart:
}
next_element:
gst_object_unref (qelement);
/* if queue is empty now, continue with a non-sink */
if (g_queue_is_empty (elem_queue)) {
GstElement *non_sink;
GST_DEBUG ("sinks and upstream elements exhausted");
non_sink = g_queue_pop_head (semi_queue);
if (non_sink) {
GST_DEBUG ("found lefover non-sink %s", GST_OBJECT_NAME (non_sink));
g_queue_push_tail (elem_queue, non_sink);
}
}
}
if (have_no_preroll) {
@ -1275,25 +1304,23 @@ restart:
} else if (have_async) {
ret = GST_STATE_ASYNC;
} else {
if ((ret = parent_class->change_state (element)) == GST_STATE_SUCCESS) {
/* we can commit the state change now */
gst_element_commit_state (element);
}
ret = parent_class->change_state (element);
}
GST_CAT_DEBUG_OBJECT (GST_CAT_STATES, element,
"done changing bin's state from %s to %s, now in %s",
"done changing bin's state from %s to %s, now in %s, ret %d",
gst_element_state_get_name (old_state),
gst_element_state_get_name (pending),
gst_element_state_get_name (GST_STATE (element)));
gst_element_state_get_name (GST_STATE (element)), ret);
exit:
/* release refcounts in queue, should normally be empty unless we
* had an error. */
g_queue_foreach (elem_queue, (GFunc) gst_object_unref, NULL);
clear_queue (elem_queue, TRUE);
clear_queue (semi_queue, TRUE);
g_queue_free (elem_queue);
g_queue_foreach (semi_queue, (GFunc) gst_object_unref, NULL);
g_queue_free (semi_queue);
g_queue_free (temp);
return ret;
}