Tools/gtk/patches/libnice-0001-nicesrc-spin-the-agent-mainloop-in-a-separate-thread.patch

From 3196a96a408a90f707dff3f31fa3d05d64aeb68a Mon Sep 17 00:00:00 2001
From: Alessandro Decina <alessandro.d@gmail.com>
Date: Tue, 13 Oct 2015 12:49:19 +1100
Subject: [PATCH] nicesrc: spin the agent mainloop in a separate thread

Don't run the mainloop from the srcpad task, since that can get blocked in the
pipeline and cause unnecessary STUN retrasmissions (at best) and completely
block the agent (at worst).
---
 gst/gstnicesrc.c | 158 ++++++++++++++++++++++++++++++++-----------------------
 gst/gstnicesrc.h |   4 +-
 2 files changed, 93 insertions(+), 69 deletions(-)

diff --git a/gst/gstnicesrc.c b/gst/gstnicesrc.c
index d369e09..eb59fe9 100644
--- a/gst/gstnicesrc.c
+++ b/gst/gstnicesrc.c
@@ -48,6 +48,14 @@ GST_DEBUG_CATEGORY_STATIC (nicesrc_debug);
 
 #define BUFFER_SIZE (65536)
 
+static gboolean
+gst_nice_src_start (
+    GstBaseSrc *basesrc);
+
+static gboolean
+gst_nice_src_stop (
+    GstBaseSrc *basesrc);
+
 static GstFlowReturn
 gst_nice_src_create (
   GstPushSrc *basesrc,
@@ -57,10 +65,6 @@ static gboolean
 gst_nice_src_unlock (
     GstBaseSrc *basesrc);
 
-static gboolean
-gst_nice_src_unlock_stop (
-    GstBaseSrc *basesrc);
-
 static void
 gst_nice_src_set_property (
   GObject *object,
@@ -116,8 +120,9 @@ gst_nice_src_class_init (GstNiceSrcClass *klass)
   gstpushsrc_class->create = GST_DEBUG_FUNCPTR (gst_nice_src_create);
 
   gstbasesrc_class = (GstBaseSrcClass *) klass;
+  gstbasesrc_class->start = GST_DEBUG_FUNCPTR (gst_nice_src_start);
+  gstbasesrc_class->stop = GST_DEBUG_FUNCPTR (gst_nice_src_stop);
   gstbasesrc_class->unlock = GST_DEBUG_FUNCPTR (gst_nice_src_unlock);
-  gstbasesrc_class->unlock_stop = GST_DEBUG_FUNCPTR (gst_nice_src_unlock_stop);
 
   gobject_class = (GObjectClass *) klass;
   gobject_class->set_property = gst_nice_src_set_property;
@@ -179,9 +184,83 @@ gst_nice_src_init (GstNiceSrc *src)
   src->component_id = 0;
   src->mainctx = g_main_context_new ();
   src->mainloop = g_main_loop_new (src->mainctx, FALSE);
-  src->unlocked = FALSE;
-  src->idle_source = NULL;
   src->outbufs = g_queue_new ();
+  src->agent_io_thread = NULL;
+  g_cond_init (&src->outcond);
+}
+
+static gpointer
+gst_nice_src_agent_io_thread (gpointer data)
+{
+  GstNiceSrc *nicesrc = GST_NICE_SRC (data);
+
+  GST_INFO_OBJECT (nicesrc, "starting agent io thread");
+  g_main_loop_run (nicesrc->mainloop);
+  GST_INFO_OBJECT (nicesrc, "exiting agent io thread");
+
+  return NULL;
+}
+
+static gboolean
+main_loop_running_cb (gpointer data)
+{
+  GstNiceSrc *nicesrc = GST_NICE_SRC (data);
+
+  GST_OBJECT_LOCK (nicesrc);
+  /* _start() and _stop() could both be waiting for the mainloop to start so we
+   * need to broadcast */
+  g_cond_broadcast (&nicesrc->outcond);
+  GST_OBJECT_UNLOCK (nicesrc);
+
+  return FALSE;
+}
+
+static gboolean
+gst_nice_src_start (GstBaseSrc * basesrc)
+{
+  GstNiceSrc *nicesrc = GST_NICE_SRC (basesrc);
+  GSource *source;
+  gchar *thread_name;
+
+  GST_OBJECT_LOCK (nicesrc);
+  source = g_idle_source_new ();
+  g_source_set_callback (source,
+      (GSourceFunc) main_loop_running_cb, nicesrc, NULL);
+  g_source_attach (source, nicesrc->mainctx);
+  g_source_unref (source);
+
+  thread_name = g_strdup_printf ("%s:agent_io", GST_OBJECT_NAME (nicesrc));
+  nicesrc->agent_io_thread = g_thread_new (thread_name, gst_nice_src_agent_io_thread, nicesrc);
+  g_free (thread_name);
+  /* wait until the agent thread starts spinning the mainloop or _stop() is
+   * called */
+  while (GST_BASE_SRC_IS_STARTING (basesrc) &&
+      !g_main_loop_is_running (nicesrc->mainloop))
+    g_cond_wait (&nicesrc->outcond, GST_OBJECT_GET_LOCK (nicesrc));
+  GST_OBJECT_UNLOCK (nicesrc);
+
+  return TRUE;
+}
+
+static gboolean
+gst_nice_src_stop (GstBaseSrc * basesrc)
+{
+  GstNiceSrc *nicesrc = GST_NICE_SRC (basesrc);
+  GThread *agent_io_thread = NULL;
+
+  GST_OBJECT_LOCK (nicesrc);
+  /* here we wait for the agent thread created in _start() to be scheduled so
+   * that we don't risk calling _quit() first and then _run() on the mainloop */
+  while (!g_main_loop_is_running (nicesrc->mainloop))
+    g_cond_wait (&nicesrc->outcond, GST_OBJECT_GET_LOCK (nicesrc));
+  g_main_loop_quit (nicesrc->mainloop);
+  agent_io_thread = nicesrc->agent_io_thread;
+  nicesrc->agent_io_thread = NULL;
+  GST_OBJECT_UNLOCK (nicesrc);
+
+  g_thread_join (agent_io_thread);
+
+  return TRUE;
 }
 
 static void
@@ -207,62 +286,17 @@ gst_nice_src_read_callback (NiceAgent *agent,
 #endif
   GST_OBJECT_LOCK (nicesrc);
   g_queue_push_tail (nicesrc->outbufs, buffer);
-  g_main_loop_quit (nicesrc->mainloop);
+  g_cond_signal (&nicesrc->outcond);
   GST_OBJECT_UNLOCK (nicesrc);
 }
 
 static gboolean
-gst_nice_src_unlock_idler (gpointer data)
-{
-  GstNiceSrc *nicesrc = GST_NICE_SRC (data);
-
-  GST_OBJECT_LOCK (nicesrc);
-  if (nicesrc->unlocked)
-    g_main_loop_quit (nicesrc->mainloop);
-
-  if (nicesrc->idle_source) {
-    g_source_destroy (nicesrc->idle_source);
-    g_source_unref (nicesrc->idle_source);
-    nicesrc->idle_source = NULL;
-  }
-  GST_OBJECT_UNLOCK (nicesrc);
-
-  return FALSE;
-}
-
-static gboolean
 gst_nice_src_unlock (GstBaseSrc *src)
 {
   GstNiceSrc *nicesrc = GST_NICE_SRC (src);
 
   GST_OBJECT_LOCK (src);
-  nicesrc->unlocked = TRUE;
-
-  g_main_loop_quit (nicesrc->mainloop);
-
-  if (!nicesrc->idle_source) {
-    nicesrc->idle_source = g_idle_source_new ();
-    g_source_set_priority (nicesrc->idle_source, G_PRIORITY_HIGH);
-    g_source_set_callback (nicesrc->idle_source, gst_nice_src_unlock_idler, src, NULL);
-    g_source_attach (nicesrc->idle_source, g_main_loop_get_context (nicesrc->mainloop));
-  }
-  GST_OBJECT_UNLOCK (src);
-
-  return TRUE;
-}
-
-static gboolean
-gst_nice_src_unlock_stop (GstBaseSrc *src)
-{
-  GstNiceSrc *nicesrc = GST_NICE_SRC (src);
-
-  GST_OBJECT_LOCK (src);
-  nicesrc->unlocked = FALSE;
-  if (nicesrc->idle_source) {
-    g_source_destroy (nicesrc->idle_source);
-    g_source_unref(nicesrc->idle_source);
-  }
-  nicesrc->idle_source = NULL;
+  g_cond_signal (&nicesrc->outcond);
   GST_OBJECT_UNLOCK (src);
 
   return TRUE;
@@ -278,19 +312,8 @@ gst_nice_src_create (
   GST_LOG_OBJECT (nicesrc, "create called");
 
   GST_OBJECT_LOCK (basesrc);
-  if (nicesrc->unlocked) {
-    GST_OBJECT_UNLOCK (basesrc);
-#if GST_CHECK_VERSION (1,0,0)
-    return GST_FLOW_FLUSHING;
-#else
-    return GST_FLOW_WRONG_STATE;
-#endif
-  }
-  if (g_queue_is_empty (nicesrc->outbufs)) {
-    GST_OBJECT_UNLOCK (basesrc);
-    g_main_loop_run (nicesrc->mainloop);
-    GST_OBJECT_LOCK (basesrc);
-  }
+  if (g_queue_is_empty (nicesrc->outbufs))
+    g_cond_wait (&nicesrc->outcond, GST_OBJECT_GET_LOCK (nicesrc));
 
   *buffer = g_queue_pop_head (nicesrc->outbufs);
   GST_OBJECT_UNLOCK (basesrc);
@@ -331,6 +354,7 @@ gst_nice_src_dispose (GObject *object)
     g_queue_free (src->outbufs);
   }
   src->outbufs = NULL;
+  g_cond_clear (&src->outcond);
 
   G_OBJECT_CLASS (gst_nice_src_parent_class)->dispose (object);
 }
diff --git a/gst/gstnicesrc.h b/gst/gstnicesrc.h
index 5d3f554..2d9f674 100644
--- a/gst/gstnicesrc.h
+++ b/gst/gstnicesrc.h
@@ -68,8 +68,8 @@ struct _GstNiceSrc
   GMainContext *mainctx;
   GMainLoop *mainloop;
   GQueue *outbufs;
-  gboolean unlocked;
-  GSource *idle_source;
+  GCond outcond;
+  GThread *agent_io_thread;
 };
 
 typedef struct _GstNiceSrcClass GstNiceSrcClass;
-- 
2.3.4