[Asterisk-code-review] Add API for channel frame deferral. (asterisk[14])
George Joseph
asteriskteam at digium.com
Tue Nov 8 06:37:38 CST 2016
George Joseph has uploaded a new change for review. ( https://gerrit.asterisk.org/4340 )
Change subject: Add API for channel frame deferral.
......................................................................
Add API for channel frame deferral.
There are several places in Asterisk that have duplicated logic
for deferring important frames until later.
This commit adds a couple of API calls to facilitate this automatically.
ast_channel_start_defer_frames(): Future reads of deferrable frames on
this channel will be deferred until later.
ast_channel_stop_defer_frames(): Any frames that have been deferred get
requeued onto the channel.
ASTERISK-26343
Change-Id: I3e1b87bc6796f222442fa6f7d1b6a4706fb33641
---
M include/asterisk/channel.h
M main/channel.c
M main/channel_internal_api.c
3 files changed, 89 insertions(+), 0 deletions(-)
git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/40/4340/1
diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index 78db878..cf8c544 100644
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -967,6 +967,11 @@
* The channel is executing a subroutine or macro
*/
AST_FLAG_SUBROUTINE_EXEC = (1 << 27),
+ /*!
+ * The channel is currently in an operation where
+ * frames should be deferred.
+ */
+ AST_FLAG_DEFER_FRAMES = (1 << 28),
};
/*! \brief ast_bridge_config flags */
@@ -4661,4 +4666,37 @@
*/
enum ast_channel_error ast_channel_errno(void);
+/*!
+ * \brief Retrieve the deferred read queue.
+ */
+struct ast_readq_list *ast_channel_deferred_readq(struct ast_channel *chan);
+
+/*!
+ * \brief Start deferring deferrable frames on this channel
+ *
+ * Sometimes, a channel gets entered into a mode where a "main" application
+ * is tasked with servicing frames on the channel, but that application does
+ * not need to act on those frames. However, it would be imprudent to simply
+ * drop important frames. This function can be called so that important frames
+ * will be deferred, rather than placed in the channel frame queue as normal.
+ *
+ * \pre chan MUST be locked before calling
+ *
+ * \param chan The channel on which frames should be deferred
+ */
+void ast_channel_start_defer_frames(struct ast_channel *chan);
+
+/*!
+ * \brief Stop deferring deferrable frames on this channel
+ *
+ * When it is time to stop deferring frames on the channel, all deferred frames
+ * will be queued onto the channel's read queue so that the next servicer of
+ * the channel can handle those frames as necessary.
+ *
+ * \pre chan MUST be locked before calling
+ *
+ * \param chan The channel on which to stop deferring frames.
+ */
+void ast_channel_stop_defer_frames(struct ast_channel *chan);
+
#endif /* _ASTERISK_CHANNEL_H */
diff --git a/main/channel.c b/main/channel.c
index 6e24ee6..f00f222 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -1064,6 +1064,25 @@
return tmp;
}
+void ast_channel_start_defer_frames(struct ast_channel *chan)
+{
+ ast_set_flag(ast_channel_flags(chan), AST_FLAG_DEFER_FRAMES);
+}
+
+void ast_channel_stop_defer_frames(struct ast_channel *chan)
+{
+ ast_clear_flag(ast_channel_flags(chan), AST_FLAG_DEFER_FRAMES);
+
+ /* Move the deferred frames onto the channel read queue, ahead of other queued frames */
+ ast_queue_frame_head(chan, AST_LIST_FIRST(ast_channel_deferred_readq(chan)));
+ /* ast_frfree will mosey down the list and free them all */
+ if (!AST_LIST_EMPTY(ast_channel_deferred_readq(chan))) {
+ ast_frfree(AST_LIST_FIRST(ast_channel_deferred_readq(chan)));
+ }
+ /* Reset the list to be empty */
+ AST_LIST_HEAD_INIT_NOLOCK(ast_channel_deferred_readq(chan));
+}
+
static int __ast_queue_frame(struct ast_channel *chan, struct ast_frame *fin, int head, struct ast_frame *after)
{
struct ast_frame *f;
@@ -3885,6 +3904,32 @@
if (!AST_LIST_EMPTY(ast_channel_readq(chan))) {
int skip_dtmf = should_skip_dtmf(chan);
+ if (ast_test_flag(ast_channel_flags(chan), AST_FLAG_DEFER_FRAMES)) {
+ AST_LIST_TRAVERSE_SAFE_BEGIN(ast_channel_readq(chan), f, frame_list) {
+ if (ast_is_deferrable_frame(f)) {
+ if (f->frametype == AST_FRAME_CONTROL && f->subclass.integer == AST_CONTROL_HANGUP) {
+ struct ast_frame *dup;
+
+ /* Hangup is a special case. We want to defer the frame, but we also do not
+ * want to remove it from the frame queue. So rather than just moving the frame
+ * over, we duplicate it and move the copy to the deferred readq.
+ *
+ * The reason for this? This way, whoever calls ast_read() will get a NULL return
+ * immediately and can tell the channel has hung up and do what it needs to. Also,
+ * when frame deferral finishes, then whoever calls ast_read() next will also get
+ * the hangup.
+ */
+ dup = ast_frdup(f);
+ AST_LIST_INSERT_TAIL(ast_channel_deferred_readq(chan), dup, frame_list);
+ } else {
+ AST_LIST_INSERT_TAIL(ast_channel_deferred_readq(chan), f, frame_list);
+ AST_LIST_REMOVE_CURRENT(frame_list);
+ }
+ }
+ }
+ AST_LIST_TRAVERSE_SAFE_END;
+ }
+
AST_LIST_TRAVERSE_SAFE_BEGIN(ast_channel_readq(chan), f, frame_list) {
/* We have to be picky about which frame we pull off of the readq because
* there are cases where we want to leave DTMF frames on the queue until
diff --git a/main/channel_internal_api.c b/main/channel_internal_api.c
index 3c156d4..a30c605 100644
--- a/main/channel_internal_api.c
+++ b/main/channel_internal_api.c
@@ -223,6 +223,7 @@
struct stasis_cp_single *topics; /*!< Topic for all channel's events */
struct stasis_forward *endpoint_forward; /*!< Subscription for event forwarding to endpoint's topic */
struct stasis_forward *endpoint_cache_forward; /*!< Subscription for cache updates to endpoint's topic */
+ struct ast_readq_list deferred_readq;
};
/*! \brief The monotonically increasing integer counter for channel uniqueids */
@@ -1683,3 +1684,8 @@
return *error_code;
}
+
+struct ast_readq_list *ast_channel_deferred_readq(struct ast_channel *chan)
+{
+ return &chan->deferred_readq;
+}
--
To view, visit https://gerrit.asterisk.org/4340
To unsubscribe, visit https://gerrit.asterisk.org/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I3e1b87bc6796f222442fa6f7d1b6a4706fb33641
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 14
Gerrit-Owner: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Mark Michelson <mmichelson at digium.com>
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