gstreamer: Allow borrowing Segments from Values without copying

gstreamer-base/src/aggregator.rs

@@ -245,7 +245,7 @@ impl<O: IsA<Aggregator>> AggregatorExtManual for O {
             let f: &F = &*(f as *const F);
             f(
                 Aggregator::from_glib_borrow(this).unsafe_cast_ref(),
-                &gst::Segment::from_glib_borrow(segment),
+                gst::Segment::from_ptr(segment),
                 from_glib(pts),
                 from_glib(dts),
                 from_glib(duration),

gstreamer/src/sample.rs

@@ -173,7 +173,7 @@ impl SampleRef {
             if ptr.is_null() {
                 None
             } else {
-                Some(&*(ptr as *const crate::Segment))
+                Some(crate::Segment::from_ptr(ptr))
             }
         }
     }

gstreamer/src/segment.rs

@@ -18,6 +18,11 @@ pub type Segment = FormattedSegment<GenericFormattedValue>;
 pub struct FormattedSegment<T: FormattedValueIntrinsic>(ffi::GstSegment, PhantomData<T>);
 
 impl Segment {
+    pub unsafe fn from_ptr<'a>(ptr: *const ffi::GstSegment) -> &'a Segment {
+        assert!(!ptr.is_null());
+        &*(ptr as *const Self)
+    }
+
     pub fn reset_with_format(&mut self, format: Format) {
         unsafe {
             ffi::gst_segment_init(self.to_glib_none_mut().0, format.into_glib());
@@ -649,6 +654,18 @@ unsafe impl<'a> glib::value::FromValue<'a> for Segment {
     }
 }
 
+#[doc(hidden)]
+unsafe impl<'a> glib::value::FromValue<'a> for &'a Segment {
+    type Checker = glib::value::GenericValueTypeOrNoneChecker<Self>;
+
+    unsafe fn from_value(value: &'a glib::Value) -> Self {
+        skip_assert_initialized!();
+        Segment::from_ptr(
+            glib::gobject_ffi::g_value_get_boxed(value.to_glib_none().0) as *const ffi::GstSegment
+        )
+    }
+}
+
 #[doc(hidden)]
 impl<T: FormattedValueIntrinsic> glib::value::ToValue for FormattedSegment<T> {
     fn to_value(&self) -> glib::Value {