glib: Manually implement Source::context()

This conditionally uses the safe `dup_context()` with GLib 2.86 and
otherwise the racy `get_context()` as before.

Author: sdroege

glib/Gir.toml

@@ -837,6 +837,17 @@ concurrency = "send+sync"
     # parameter type
     ignore = true
 
+    [[object.function]]
+    name = "dup_context"
+    # implemented as the normal getter
+    manual = true
+
+    [[object.function]]
+    name = "get_context"
+    # implemented conditionally around this or
+    # dup_context() (see above)
+    manual = true
+
 [[object]]
 name = "GLib.ThreadPool"
 status = "manual"

glib/src/source.rs

@@ -1270,4 +1270,18 @@ impl Source {
             ))
         }
     }
+
+    #[doc(alias = "g_source_get_context")]
+    #[doc(alias = "get_context")]
+    #[doc(alias = "g_source_dup_context")]
+    pub fn context(&self) -> Option<MainContext> {
+        #[cfg(feature = "v2_86")]
+        unsafe {
+            from_glib_full(ffi::g_source_dup_context(self.to_glib_none().0))
+        }
+        #[cfg(not(feature = "v2_86"))]
+        unsafe {
+            from_glib_none(ffi::g_source_get_context(self.to_glib_none().0))
+        }
+    }
 }