video_frame: refactor traits

this adds an IsVideoFrame trait that makes it easier to provide all the
shared methods between VideoFrame, VideoFrameRef, GLVideoFrame and
GLVideoFrameRef. Now only a single method, `as_non_null_ptr()` has to be
implemented and the rest of the shared methods will be provided by the
`VideoFrameExt` trait.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer-rs/-/merge_requests/1312>

gstreamer-gl/src/gl_video_frame.rs

@@ -4,7 +4,7 @@ use std::{marker::PhantomData, mem, ptr};
 
 use crate::GLMemoryRef;
 use glib::translate::{from_glib, Borrowed, ToGlibPtr};
-use gst_video::VideoFrameExt;
+use gst_video::{video_frame::IsVideoFrame, VideoFrameExt};
 
 pub enum Readable {}
 pub enum Writable {}
@@ -23,23 +23,10 @@ unsafe impl<T> Sync for GLVideoFrame<T> {}
 
 // TODO implement Debug for GLVideoFrame
 
-impl<T> VideoFrameExt for GLVideoFrame<T> {
+impl<T> IsVideoFrame for GLVideoFrame<T> {
     #[inline]
-    fn info(&self) -> &gst_video::VideoInfo {
+    fn as_non_null_ptr(&self) -> std::ptr::NonNull<gst_video::ffi::GstVideoFrame> {
-        unsafe {
+        std::ptr::NonNull::from(&self.frame)
-            &*(&self.frame.info as *const gst_video::ffi::GstVideoInfo
-                as *const gst_video::VideoInfo)
-        }
-    }
-
-    #[inline]
-    fn flags(&self) -> gst_video::VideoFrameFlags {
-        unsafe { from_glib(self.frame.flags) }
-    }
-
-    #[inline]
-    fn id(&self) -> i32 {
-        self.frame.id
     }
 }
 
@@ -82,11 +69,6 @@ impl<T> GLVideoFrame<T> {
         }
     }
 
-    #[inline]
-    pub fn buffer(&self) -> &gst::BufferRef {
-        unsafe { gst::BufferRef::from_ptr(self.frame.buffer) }
-    }
-
     #[inline]
     pub unsafe fn from_glib_full(frame: gst_video::ffi::GstVideoFrame) -> Self {
         let buffer = gst::Buffer::from_glib_none(frame.buffer);
@@ -97,11 +79,6 @@ impl<T> GLVideoFrame<T> {
         }
     }
 
-    #[inline]
-    pub fn as_ptr(&self) -> *const gst_video::ffi::GstVideoFrame {
-        &self.frame
-    }
-
     #[inline]
     pub fn into_raw(self) -> gst_video::ffi::GstVideoFrame {
         unsafe {
@@ -248,33 +225,13 @@ pub struct GLVideoFrameRef<T> {
 unsafe impl<T> Send for GLVideoFrameRef<T> {}
 unsafe impl<T> Sync for GLVideoFrameRef<T> {}
 
-impl<T> VideoFrameExt for GLVideoFrameRef<T> {
+impl<T> IsVideoFrame for GLVideoFrameRef<T> {
     #[inline]
-    fn info(&self) -> &gst_video::VideoInfo {
+    fn as_non_null_ptr(&self) -> std::ptr::NonNull<gst_video::ffi::GstVideoFrame> {
-        unsafe {
+        std::ptr::NonNull::from(&self.frame)
-            &*(&self.frame.info as *const gst_video::ffi::GstVideoInfo
-                as *const gst_video::VideoInfo)
-        }
-    }
-
-    #[inline]
-    fn flags(&self) -> gst_video::VideoFrameFlags {
-        unsafe { from_glib(self.frame.flags) }
-    }
-
-    #[inline]
-    fn id(&self) -> i32 {
-        self.frame.id
     }
 }
 // TODO implement Debug for GLVideoFrameRef
-//
-impl<T> GLVideoFrameRef<T> {
-    #[inline]
-    pub fn as_ptr(&self) -> *const gst_video::ffi::GstVideoFrame {
-        &self.frame
-    }
-}
 
 impl<'a> GLVideoFrameRef<&'a gst::BufferRef> {
     #[inline]
@@ -351,10 +308,6 @@ impl<'a> GLVideoFrameRef<&'a gst::BufferRef> {
         }
     }
 
-    pub fn buffer(&self) -> &gst::BufferRef {
-        unsafe { gst::BufferRef::from_ptr(self.frame.buffer) }
-    }
-
     pub fn texture_id(&self, idx: u32) -> Option<u32> {
         let len = buffer_n_gl_memory(self.buffer())?;
 

gstreamer-video/src/subclass/video_filter.rs

@@ -3,7 +3,7 @@
 use glib::translate::*;
 use gst_base::{prelude::*, subclass::prelude::*};
 
-use crate::{VideoFilter, VideoFrameRef, VideoInfo};
+use crate::{VideoFilter, VideoFrameExt, VideoFrameRef, VideoInfo};
 
 pub trait VideoFilterImpl: VideoFilterImplExt + BaseTransformImpl {
     fn set_info(

gstreamer-video/src/video_converter.rs

@@ -2,6 +2,7 @@
 
 use std::{ops, ptr};
 
+use crate::VideoFrameExt;
 use glib::translate::*;
 
 #[derive(Debug)]

gstreamer-video/src/video_frame.rs

@@ -7,6 +7,17 @@ use glib::translate::{from_glib, from_glib_none, Borrowed, ToGlibPtr};
 pub enum Readable {}
 pub enum Writable {}
 
+pub trait IsVideoFrame {
+    fn as_non_null_ptr(&self) -> std::ptr::NonNull<ffi::GstVideoFrame>;
+}
+
+impl<T> IsVideoFrame for VideoFrame<T> {
+    #[inline]
+    fn as_non_null_ptr(&self) -> std::ptr::NonNull<ffi::GstVideoFrame> {
+        std::ptr::NonNull::from(&self.frame)
+    }
+}
+
 pub struct VideoFrame<T> {
     frame: ffi::GstVideoFrame,
     buffer: gst::Buffer,
@@ -27,10 +38,40 @@ impl<T> fmt::Debug for VideoFrame<T> {
     }
 }
 
-pub trait VideoFrameExt {
+mod sealed {
-    fn id(&self) -> i32;
+    pub trait Sealed {}
-    fn info(&self) -> &crate::VideoInfo;
+    impl<T: super::IsVideoFrame> Sealed for T {}
-    fn flags(&self) -> crate::VideoFrameFlags;
+}
+
+pub trait VideoFrameExt: sealed::Sealed + IsVideoFrame {
+    #[inline]
+    fn as_ptr(&self) -> *const ffi::GstVideoFrame {
+        self.as_non_null_ptr().as_ptr() as _
+    }
+
+    #[inline]
+    fn info(&self) -> &crate::VideoInfo {
+        unsafe {
+            let frame = self.as_non_null_ptr().as_ref();
+            let info = &frame.info as *const ffi::GstVideoInfo as *const crate::VideoInfo;
+            &*info
+        }
+    }
+
+    #[inline]
+    fn flags(&self) -> crate::VideoFrameFlags {
+        unsafe { from_glib(self.as_non_null_ptr().as_ref().flags) }
+    }
+
+    #[inline]
+    fn id(&self) -> i32 {
+        unsafe { self.as_non_null_ptr().as_ref().id }
+    }
+
+    #[inline]
+    fn buffer(&self) -> &gst::BufferRef {
+        unsafe { gst::BufferRef::from_ptr(self.as_non_null_ptr().as_ref().buffer) }
+    }
 
     #[inline]
     fn format(&self) -> crate::VideoFormat {
@@ -150,22 +191,7 @@ pub trait VideoFrameExt {
     }
 }
 
-impl<T> VideoFrameExt for VideoFrame<T> {
+impl<O: IsVideoFrame> VideoFrameExt for O {}
-    #[inline]
-    fn info(&self) -> &crate::VideoInfo {
-        unsafe { &*(&self.frame.info as *const ffi::GstVideoInfo as *const crate::VideoInfo) }
-    }
-
-    #[inline]
-    fn flags(&self) -> crate::VideoFrameFlags {
-        unsafe { from_glib(self.frame.flags) }
-    }
-
-    #[inline]
-    fn id(&self) -> i32 {
-        self.frame.id
-    }
-}
 
 impl<T> VideoFrame<T> {
     #[inline]
@@ -219,7 +245,7 @@ impl<T> VideoFrame<T> {
     }
 
     #[inline]
-    fn buffer(&self) -> &gst::BufferRef {
+    pub fn buffer(&self) -> &gst::BufferRef {
         unsafe { gst::BufferRef::from_ptr(self.frame.buffer) }
     }
 
@@ -279,11 +305,6 @@ impl<T> VideoFrame<T> {
         }
     }
 
-    #[inline]
-    pub fn as_ptr(&self) -> *const ffi::GstVideoFrame {
-        &self.frame
-    }
-
     #[inline]
     pub fn into_raw(self) -> ffi::GstVideoFrame {
         unsafe {
@@ -511,6 +532,13 @@ pub struct VideoFrameRef<T> {
     phantom: PhantomData<T>,
 }
 
+impl<T> IsVideoFrame for VideoFrameRef<T> {
+    #[inline]
+    fn as_non_null_ptr(&self) -> std::ptr::NonNull<ffi::GstVideoFrame> {
+        std::ptr::NonNull::from(&self.frame)
+    }
+}
+
 impl<T> fmt::Debug for VideoFrameRef<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         f.debug_struct("VideoFrameRef")
@@ -524,23 +552,6 @@ impl<T> fmt::Debug for VideoFrameRef<T> {
     }
 }
 
-impl<T> VideoFrameExt for VideoFrameRef<T> {
-    #[inline]
-    fn info(&self) -> &crate::VideoInfo {
-        unsafe { &*(&self.frame.info as *const ffi::GstVideoInfo as *const crate::VideoInfo) }
-    }
-
-    #[inline]
-    fn flags(&self) -> crate::VideoFrameFlags {
-        unsafe { from_glib(self.frame.flags) }
-    }
-
-    #[inline]
-    fn id(&self) -> i32 {
-        self.frame.id
-    }
-}
-
 impl<T> VideoFrameRef<T> {
     #[doc(alias = "gst_video_frame_copy")]
     pub fn copy(
@@ -619,11 +630,6 @@ impl<T> VideoFrameRef<T> {
             ))
         }
     }
-
-    #[inline]
-    pub fn as_ptr(&self) -> *const ffi::GstVideoFrame {
-        &self.frame
-    }
 }
 
 impl<'a> VideoFrameRef<&'a gst::BufferRef> {
@@ -711,11 +717,6 @@ impl<'a> VideoFrameRef<&'a gst::BufferRef> {
             }
         }
     }
-
-    #[inline]
-    pub fn buffer(&self) -> &gst::BufferRef {
-        unsafe { gst::BufferRef::from_ptr(self.frame.buffer) }
-    }
 }
 
 impl<'a> VideoFrameRef<&'a mut gst::BufferRef> {