gst: pad: Add method to store retrieve pending buffers

These will be useful for streaming. The requestComplete callback will
store the buffers on each pads so that the _run() can pick them up
and push them through the pads from a streaming thread.

Signed-off-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

2 files changed, 31 insertions, 0 deletions

diff --git a/src/gstreamer/gstlibcamerapad.cpp b/src/gstreamer/gstlibcamerapad.cpp
index 8616e067..49dd35b8 100644
--- a/src/gstreamer/gstlibcamerapad.cpp
+++ b/src/gstreamer/gstlibcamerapad.cpp
@@ -18,6 +18,7 @@ struct _GstLibcameraPad {
 	GstPad parent;
 	StreamRole role;
 	GstLibcameraPool *pool;
+	GQueue pending_buffers;
 };
 
 enum {
@@ -137,3 +138,29 @@ gst_libcamera_pad_get_stream(GstPad *pad)
 
 	return nullptr;
 }
+
+void
+gst_libcamera_pad_queue_buffer(GstPad *pad, GstBuffer *buffer)
+{
+	auto *self = GST_LIBCAMERA_PAD(pad);
+	GLibLocker lock(GST_OBJECT(self));
+
+	g_queue_push_head(&self->pending_buffers, buffer);
+}
+
+GstFlowReturn
+gst_libcamera_pad_push_pending(GstPad *pad)
+{
+	auto *self = GST_LIBCAMERA_PAD(pad);
+	GstBuffer *buffer;
+
+	{
+		GLibLocker lock(GST_OBJECT(self));
+		buffer = GST_BUFFER(g_queue_pop_tail(&self->pending_buffers));
+	}
+
+	if (!buffer)
+		return GST_FLOW_OK;
+
+	return gst_pad_push(pad, buffer);
+}
diff --git a/src/gstreamer/gstlibcamerapad.h b/src/gstreamer/gstlibcamerapad.h
index f7dfc281..2e9ec202 100644
--- a/src/gstreamer/gstlibcamerapad.h
+++ b/src/gstreamer/gstlibcamerapad.h
@@ -26,4 +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_queue_buffer(GstPad *pad, GstBuffer *buffer);
+
+GstFlowReturn gst_libcamera_pad_push_pending(GstPad *pad);
+
 #endif /* __GST_LIBCAMERA_PAD_H__ */