Hack around a soundness issue

Prevent `CBox` from being opaquable if it isn't `Send`. This effectively works around #18, albeit does not solve it. This will prevent `!Send` futures from being turned into CGlue's opaque, `CBox: Send`.
h33p · Jul 30, 2024 · 7a76fcc · 7a76fcc
1 parent 6eb2baa
commit 7a76fcc
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diff --git a/Cargo.lock b/Cargo.lock
diff --git a/cglue/Cargo.toml b/cglue/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "cglue"
-version = "0.3.3"
+version = "0.3.4"
 authors = ["Aurimas Blažulionis <[email protected]>"]
 edition = "2018"
 description = "FFI safe abstractions for making plugins and C-compatible libraries"

diff --git a/cglue/src/boxed.rs b/cglue/src/boxed.rs
@@ -74,7 +74,8 @@ impl<T> Drop for CBox<'_, T> {
     }
 }
 
-unsafe impl<'a, T> Opaquable for CBox<'a, T> {
+// FIXME: express both Send and !Send box safely (https://github.com/h33p/cglue/issues/18)
+unsafe impl<'a, T: Send> Opaquable for CBox<'a, T> {
     type OpaqueTarget = CBox<'a, c_void>;
 }
 

diff --git a/cglue/src/tests/extra/wrap_default.rs b/cglue/src/tests/extra/wrap_default.rs
@@ -11,7 +11,7 @@ pub trait ExtraFeature {
 }
 
 #[cglue_trait]
-pub trait Basic: Sized {
+pub trait Basic: Sized + Send + Sync {
     #[vtbl_only('_, wrap_with_obj(ExtraFeature))]
     fn b_1(&self) -> ExtraFeatureWrap<&Self> {
         ExtraFeatureWrap { _v: self }

diff --git a/cglue/src/tests/simple/trait_groups.rs b/cglue/src/tests/simple/trait_groups.rs
@@ -22,7 +22,7 @@ fn test_group() {
     // and a ref group impl.
     //
     // Having both requres explicitly specifying inner type like done here.
-    fn into_test<'a, T: Into<TestGroupBaseBox<'a, T>> + 'a>(t: T) -> TestGroupBox<'a> {
+    fn into_test<'a, T: Into<TestGroupBaseBox<'a, T>> + Send + 'a>(t: T) -> TestGroupBox<'a> {
         group_obj!(t as TestGroup)
     }
     let _ = into_test(&a);