[1/4] gstreamer: Document improvements when updating minimum GStreamer version
diff mbox series

Message ID 20250522125521.6465-2-laurent.pinchart@ideasonboard.com
State Superseded
Headers show
Series
  • gstreamer: Miscellaneous cleanups + one fix
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Commit Message

Laurent Pinchart May 22, 2025, 12:55 p.m. UTC 
A const_cast<> was recently added to fix a compilation issue with older
GStreamer versions. Add a comment to indicate it can be removed when
bumping the minimum GStreamer version requirement. While at it, also
document a possible future improvement in the same function, and wrap
long lines.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
 src/gstreamer/gstlibcamerasrc.cpp | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

Comments

Nicolas Dufresne May 22, 2025, 5:25 p.m. UTC | #1 
Hi,

Le jeudi 22 mai 2025 à 14:55 +0200, Laurent Pinchart a écrit :
> A const_cast<> was recently added to fix a compilation issue with older
> GStreamer versions. Add a comment to indicate it can be removed when
> bumping the minimum GStreamer version requirement. While at it, also
> document a possible future improvement in the same function, and wrap
> long lines.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  src/gstreamer/gstlibcamerasrc.cpp | 18 +++++++++++++++---
>  1 file changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> index b34f089778ec..70bb0606c72c 100644
> --- a/src/gstreamer/gstlibcamerasrc.cpp
> +++ b/src/gstreamer/gstlibcamerasrc.cpp
> @@ -285,10 +285,17 @@ gst_libcamera_extrapolate_info(GstVideoInfo *info, guint32 stride)
>  }
>  
>  static GstFlowReturn
> -gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoInfo *dest_info, guint32 stride)
> +gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest,
> +			       const GstVideoInfo *dest_info, guint32 stride)
>  {
> -	GstVideoInfo src_info = *dest_info;
> +	/*
> +	 * When dropping support for versions earlier than v1.22.0, use
> +	 *
> +	 * g_auto (GstVideoFrame) src_frame = GST_VIDEO_FRAME_INIT;
> +	 * g_auto (GstVideoFrame) dest_frame = GST_VIDEO_FRAME_INIT;

Do you think your readers will understand that g_auto() allows the removal of all
the unmap() calls ? Otherwise I'd add this to the comment too.

> 
> +	 */
>  	GstVideoFrame src_frame, dest_frame;
> +	GstVideoInfo src_info = *dest_info;
>  
>  	gst_libcamera_extrapolate_info(&src_info, stride);
>  	src_info.size = gst_buffer_get_size(src);
> @@ -298,7 +305,12 @@ gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoIn
>  		return GST_FLOW_ERROR;
>  	}
>  
> -	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info), dest, GST_MAP_WRITE)) {
> +	/*
> +	 * When dropping support for versions earlier than 1.20.0, drop the
> +	 * const_cast<>().
> +	 */
> +	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info),
> +				 dest, GST_MAP_WRITE)) {
>  		GST_ERROR("Could not map dest buffer");
>  		gst_video_frame_unmap(&src_frame);
>  		return GST_FLOW_ERROR;
> 

Nothing major otherwise, feel free to edit and add:

Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

Nicolas
Laurent Pinchart May 28, 2025, 3:46 p.m. UTC | #2 
On Thu, May 22, 2025 at 01:25:24PM -0400, Nicolas Dufresne wrote:
> Le jeudi 22 mai 2025 à 14:55 +0200, Laurent Pinchart a écrit :
> > A const_cast<> was recently added to fix a compilation issue with older
> > GStreamer versions. Add a comment to indicate it can be removed when
> > bumping the minimum GStreamer version requirement. While at it, also
> > document a possible future improvement in the same function, and wrap
> > long lines.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> >  src/gstreamer/gstlibcamerasrc.cpp | 18 +++++++++++++++---
> >  1 file changed, 15 insertions(+), 3 deletions(-)
> > 
> > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > index b34f089778ec..70bb0606c72c 100644
> > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > @@ -285,10 +285,17 @@ gst_libcamera_extrapolate_info(GstVideoInfo *info, guint32 stride)
> >  }
> >  
> >  static GstFlowReturn
> > -gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoInfo *dest_info, guint32 stride)
> > +gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest,
> > +			       const GstVideoInfo *dest_info, guint32 stride)
> >  {
> > -	GstVideoInfo src_info = *dest_info;
> > +	/*
> > +	 * When dropping support for versions earlier than v1.22.0, use
> > +	 *
> > +	 * g_auto (GstVideoFrame) src_frame = GST_VIDEO_FRAME_INIT;
> > +	 * g_auto (GstVideoFrame) dest_frame = GST_VIDEO_FRAME_INIT;
> 
> Do you think your readers will understand that g_auto() allows the removal of all
> the unmap() calls ? Otherwise I'd add this to the comment too.

That's a good idea. I'll expand the comment to

	/*
	 * When dropping support for versions earlier than v1.22.0, use
	 *
	 * g_auto (GstVideoFrame) src_frame = GST_VIDEO_FRAME_INIT;
	 * g_auto (GstVideoFrame) dest_frame = GST_VIDEO_FRAME_INIT;
	 *
	 * and drop the gst_video_frame_unmap() calls.
	 */

> > 
> > +	 */
> >  	GstVideoFrame src_frame, dest_frame;
> > +	GstVideoInfo src_info = *dest_info;
> >  
> >  	gst_libcamera_extrapolate_info(&src_info, stride);
> >  	src_info.size = gst_buffer_get_size(src);
> > @@ -298,7 +305,12 @@ gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoIn
> >  		return GST_FLOW_ERROR;
> >  	}
> >  
> > -	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info), dest, GST_MAP_WRITE)) {
> > +	/*
> > +	 * When dropping support for versions earlier than 1.20.0, drop the
> > +	 * const_cast<>().
> > +	 */
> > +	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info),
> > +				 dest, GST_MAP_WRITE)) {
> >  		GST_ERROR("Could not map dest buffer");
> >  		gst_video_frame_unmap(&src_frame);
> >  		return GST_FLOW_ERROR;
> 
> Nothing major otherwise, feel free to edit and add:
> 
> Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>
Nicolas Dufresne May 28, 2025, 3:54 p.m. UTC | #3 
Le mercredi 28 mai 2025 à 17:46 +0200, Laurent Pinchart a écrit :
> On Thu, May 22, 2025 at 01:25:24PM -0400, Nicolas Dufresne wrote:
> > Le jeudi 22 mai 2025 à 14:55 +0200, Laurent Pinchart a écrit :
> > > A const_cast<> was recently added to fix a compilation issue with older
> > > GStreamer versions. Add a comment to indicate it can be removed when
> > > bumping the minimum GStreamer version requirement. While at it, also
> > > document a possible future improvement in the same function, and wrap
> > > long lines.
> > > 
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > ---
> > >  src/gstreamer/gstlibcamerasrc.cpp | 18 +++++++++++++++---
> > >  1 file changed, 15 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
> > > index b34f089778ec..70bb0606c72c 100644
> > > --- a/src/gstreamer/gstlibcamerasrc.cpp
> > > +++ b/src/gstreamer/gstlibcamerasrc.cpp
> > > @@ -285,10 +285,17 @@ gst_libcamera_extrapolate_info(GstVideoInfo *info, guint32 stride)
> > >  }
> > >  
> > >  static GstFlowReturn
> > > -gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoInfo *dest_info, guint32 stride)
> > > +gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest,
> > > +			       const GstVideoInfo *dest_info, guint32 stride)
> > >  {
> > > -	GstVideoInfo src_info = *dest_info;
> > > +	/*
> > > +	 * When dropping support for versions earlier than v1.22.0, use
> > > +	 *
> > > +	 * g_auto (GstVideoFrame) src_frame = GST_VIDEO_FRAME_INIT;
> > > +	 * g_auto (GstVideoFrame) dest_frame = GST_VIDEO_FRAME_INIT;
> > 
> > Do you think your readers will understand that g_auto() allows the removal of all
> > the unmap() calls ? Otherwise I'd add this to the comment too.
> 
> That's a good idea. I'll expand the comment to
> 
> 	/*
> 	 * When dropping support for versions earlier than v1.22.0, use
> 	 *
> 	 * g_auto (GstVideoFrame) src_frame = GST_VIDEO_FRAME_INIT;
> 	 * g_auto (GstVideoFrame) dest_frame = GST_VIDEO_FRAME_INIT;
> 	 *
> 	 * and drop the gst_video_frame_unmap() calls.
> 	 */

Perfect!

> 
> > > 
> > > +	 */
> > >  	GstVideoFrame src_frame, dest_frame;
> > > +	GstVideoInfo src_info = *dest_info;
> > >  
> > >  	gst_libcamera_extrapolate_info(&src_info, stride);
> > >  	src_info.size = gst_buffer_get_size(src);
> > > @@ -298,7 +305,12 @@ gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoIn
> > >  		return GST_FLOW_ERROR;
> > >  	}
> > >  
> > > -	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info), dest, GST_MAP_WRITE)) {
> > > +	/*
> > > +	 * When dropping support for versions earlier than 1.20.0, drop the
> > > +	 * const_cast<>().
> > > +	 */
> > > +	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info),
> > > +				 dest, GST_MAP_WRITE)) {
> > >  		GST_ERROR("Could not map dest buffer");
> > >  		gst_video_frame_unmap(&src_frame);
> > >  		return GST_FLOW_ERROR;
> > 
> > Nothing major otherwise, feel free to edit and add:
> > 
> > Reviewed-by: Nicolas Dufresne <nicolas.dufresne@collabora.com>

Patch
diff mbox series 

diff --git a/src/gstreamer/gstlibcamerasrc.cpp b/src/gstreamer/gstlibcamerasrc.cpp
index b34f089778ec..70bb0606c72c 100644
--- a/src/gstreamer/gstlibcamerasrc.cpp
+++ b/src/gstreamer/gstlibcamerasrc.cpp
@@ -285,10 +285,17 @@  gst_libcamera_extrapolate_info(GstVideoInfo *info, guint32 stride)
 }
 
 static GstFlowReturn
-gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoInfo *dest_info, guint32 stride)
+gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest,
+			       const GstVideoInfo *dest_info, guint32 stride)
 {
-	GstVideoInfo src_info = *dest_info;
+	/*
+	 * When dropping support for versions earlier than v1.22.0, use
+	 *
+	 * g_auto (GstVideoFrame) src_frame = GST_VIDEO_FRAME_INIT;
+	 * g_auto (GstVideoFrame) dest_frame = GST_VIDEO_FRAME_INIT;
+	 */
 	GstVideoFrame src_frame, dest_frame;
+	GstVideoInfo src_info = *dest_info;
 
 	gst_libcamera_extrapolate_info(&src_info, stride);
 	src_info.size = gst_buffer_get_size(src);
@@ -298,7 +305,12 @@  gst_libcamera_video_frame_copy(GstBuffer *src, GstBuffer *dest, const GstVideoIn
 		return GST_FLOW_ERROR;
 	}
 
-	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info), dest, GST_MAP_WRITE)) {
+	/*
+	 * When dropping support for versions earlier than 1.20.0, drop the
+	 * const_cast<>().
+	 */
+	if (!gst_video_frame_map(&dest_frame, const_cast<GstVideoInfo *>(dest_info),
+				 dest, GST_MAP_WRITE)) {
 		GST_ERROR("Could not map dest buffer");
 		gst_video_frame_unmap(&src_frame);
 		return GST_FLOW_ERROR;