[Spice-devel] [PATCH spice-streaming-agent 3/4] gst-plugin: Free input buffer and XImage as soon as possible

[Frediano Ziglio]

> 
> ---
>  src/gst-plugin.cpp | 31 ++++++++++++++++++++-----------
>  1 file changed, 20 insertions(+), 11 deletions(-)
> 
> diff --git a/src/gst-plugin.cpp b/src/gst-plugin.cpp
> index 0a1d041..c7412c5 100644
> --- a/src/gst-plugin.cpp
> +++ b/src/gst-plugin.cpp
> @@ -67,6 +67,15 @@ struct GstSampleDeleter {
>  
>  using GstSampleUPtr = std::unique_ptr<GstSample, GstSampleDeleter>;
>  
> +struct GstBufferDeleter {
> +    void operator()(GstBuffer* p)
> +    {
> +        gst_buffer_unref(p);
> +    }
> +};
> +
> +using GstBufferUPtr = std::unique_ptr<GstBuffer, GstBufferDeleter>;
> +
>  class GstreamerFrameCapture final : public FrameCapture
>  {
>  public:
> @@ -86,7 +95,6 @@ private:
>      Display *const dpy;
>  #if XLIB_CAPTURE
>      void xlib_capture();
> -    XImage *image = nullptr;
>  #endif
>      GstObjectUPtr<GstElement> pipeline, capture, sink;
>      GstSampleUPtr sample;
> @@ -306,12 +314,6 @@ void GstreamerFrameCapture::free_sample()
>          gst_buffer_unmap(gst_sample_get_buffer(sample.get()), &map);
>          sample.reset();
>      }
> -#if XLIB_CAPTURE
> -    if(image) {
> -        image->f.destroy_image(image);
> -        image = nullptr;
> -    }
> -#endif
>  }
>  
>  GstreamerFrameCapture::~GstreamerFrameCapture()
> @@ -327,9 +329,14 @@ void GstreamerFrameCapture::Reset()
>  }
>  
>  #if XLIB_CAPTURE
> +void free_ximage(gpointer data) {

bracket on next line

> +    ((XImage*)data)->f.destroy_image((XImage*)data);
> +}
> +
>  void GstreamerFrameCapture::xlib_capture()
>  {
>      int screen = XDefaultScreen(dpy);
> +    XImage *image = nullptr;
>  

I would declare + initialize on the same line

>      Window win = RootWindow(dpy, screen);
>      XWindowAttributes win_info;
> @@ -355,9 +362,11 @@ void GstreamerFrameCapture::xlib_capture()
>          throw std::runtime_error("Cannot capture from X");
>      }
>  
> -    GstBuffer *buf;
> -    buf = gst_buffer_new_wrapped(image->data, image->height *
> image->bytes_per_line);
> -    if (!buf) {
> +    GstBufferUPtr buf(gst_buffer_new_wrapped_full((GstMemoryFlags)0,
> image->data,
> +                                                  image->height *
> image->bytes_per_line, 0,
> +                                                  image->height *
> image->bytes_per_line, image,
> +                                                  free_ximage));
> +    if (!buf.get()) {
>          throw std::runtime_error("Failed to wrap image in gstreamer
>          buffer");
>      }
>  
> @@ -369,7 +378,7 @@ void GstreamerFrameCapture::xlib_capture()
>                                           nullptr));
>  
>      // Push sample
> -    GstSampleUPtr appsrc_sample(gst_sample_new(buf, caps.get(), nullptr,
> nullptr));
> +    GstSampleUPtr appsrc_sample(gst_sample_new(buf.get(), caps.get(),
> nullptr, nullptr));

I'm a bit confused on reference counting here.
The change seems to indicate that now "buf" is freed automatically
(as the unique_ptr).
So, is this patch also fixing a memory leak ?

>      if (gst_app_src_push_sample(GST_APP_SRC(capture.get()),
>      appsrc_sample.get()) != GST_FLOW_OK) {
>          throw std::runtime_error("gstramer appsrc element cannot push
>          sample");
>      }

Frediano