[libcamera-devel] [RFC PATCH v2] gstreamer: Factor out _pad_push_stream_start from _task_enter

[Vedant Paranjape]

This patch creates gst_libcamera_pad_push_stream_start function to
create stream id and to push the stream start.

Update functional code in gst_libcamera_src_task_enter(), which creates
stream id and pushes the stream start with the refactored
function gst_libcamera_pad_push_stream_start().

Signed-off-by: Vedant Paranjape <vedantparanjape160201 at gmail.com>
---
 src/gstreamer/gstlibcamerapad.cpp | 19 +++++++++++++++++++
 src/gstreamer/gstlibcamerapad.h   |  2 ++
 src/gstreamer/gstlibcamerasrc.cpp |  7 +------
 3 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/src/gstreamer/gstlibcamerapad.cpp b/src/gstreamer/gstlibcamerapad.cpp
index c00e81c8..d4211050 100644
--- a/src/gstreamer/gstlibcamerapad.cpp
+++ b/src/gstreamer/gstlibcamerapad.cpp
@@ -20,6 +20,7 @@ struct _GstLibcameraPad {
 	GstLibcameraPool *pool;
 	GQueue pending_buffers;
 	GstClockTime latency;
+	gint stream_id_num;
 };
 
 enum {
@@ -81,6 +82,7 @@ static void
 gst_libcamera_pad_init(GstLibcameraPad *self)
 {
 	GST_PAD_QUERYFUNC(self) = gst_libcamera_pad_query;
+	self->stream_id_num = 0;
 }
 
 static GType
@@ -155,6 +157,23 @@ gst_libcamera_pad_get_stream(GstPad *pad)
 	return nullptr;
 }
 
+void
+gst_libcamera_pad_push_stream_start(GstPad *pad, const guint group_id)
+{
+	auto *self = GST_LIBCAMERA_PAD(pad);	
+	{
+		GLibLocker lock(GST_OBJECT(self));
+		self->stream_id_num++;
+	}
+
+	g_autoptr(GstElement) element = gst_pad_get_parent_element(pad);
+	g_autofree gchar *stream_id_intermediate = g_strdup_printf("%i%i", group_id, self->stream_id_num);
+	g_autofree gchar *stream_id = gst_pad_create_stream_id(pad, element, stream_id_intermediate);
+	GstEvent *event = gst_event_new_stream_start(stream_id);
+	gst_event_set_group_id(event, group_id);
+	gst_pad_push_event(pad, event);
+}
+
 void
 gst_libcamera_pad_queue_buffer(GstPad *pad, GstBuffer *buffer)
 {
diff --git a/src/gstreamer/gstlibcamerapad.h b/src/gstreamer/gstlibcamerapad.h
index 779f2d13..7693374f 100644
--- a/src/gstreamer/gstlibcamerapad.h
+++ b/src/gstreamer/gstlibcamerapad.h
@@ -26,6 +26,8 @@ void gst_libcamera_pad_set_pool(GstPad *pad, GstLibcameraPool *pool);
 
 libcamera::Stream *gst_libcamera_pad_get_stream(GstPad *pad);
 
+void gst_libcamera_pad_push_stream_start(GstPad *pad, const guint group_id);
+
 void gst_libcamera_pad_queue_buffer(GstPad *pad, GstBuffer *buffer);
 
 GstFlowReturn gst_libcamera_pad_push_pending(GstPad *pad);
diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index b18f1efb..bb8ea07a 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -361,15 +361,10 @@ gst_libcamera_src_task_enter(GstTask *task, [[maybe_unused]] GThread *thread,
 
 	GST_DEBUG_OBJECT(self, "Streaming thread has started");
 
-	gint stream_id_num = 0;
 	StreamRoles roles;
 	for (GstPad *srcpad : state->srcpads_) {
 		/* Create stream-id and push stream-start. */
-		g_autofree gchar *stream_id_intermediate = g_strdup_printf("%i%i", state->group_id_, stream_id_num++);
-		g_autofree gchar *stream_id = gst_pad_create_stream_id(srcpad, GST_ELEMENT(self), stream_id_intermediate);
-		GstEvent *event = gst_event_new_stream_start(stream_id);
-		gst_event_set_group_id(event, state->group_id_);
-		gst_pad_push_event(srcpad, event);
+		gst_libcamera_pad_push_stream_start(srcpad, state->group_id_);
 
 		/* Collect the streams roles for the next iteration. */
 		roles.push_back(gst_libcamera_pad_get_role(srcpad));
-- 
2.25.1