From 20ac231146cde04487e3aaec410ba4c2992e5117 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Mon, 27 Jun 2022 22:19:42 +0300
Subject: [PATCH] gstreamer: Allow borrowing `Segment`s from `Value`s without
 copying

---
 gstreamer-base/src/aggregator.rs |  2 +-
 gstreamer/src/sample.rs          |  2 +-
 gstreamer/src/segment.rs         | 17 +++++++++++++++++
 3 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/gstreamer-base/src/aggregator.rs b/gstreamer-base/src/aggregator.rs
index eee4d91c3..8ac0dce86 100644
--- a/gstreamer-base/src/aggregator.rs
+++ b/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),
diff --git a/gstreamer/src/sample.rs b/gstreamer/src/sample.rs
index 2208867cf..bd02d2dbc 100644
--- a/gstreamer/src/sample.rs
+++ b/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))
             }
         }
     }
diff --git a/gstreamer/src/segment.rs b/gstreamer/src/segment.rs
index 625bdff67..f4e1e926d 100644
--- a/gstreamer/src/segment.rs
+++ b/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 {