Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 52 insertions, 0 deletions

diff --git a/third_party/rust/uniffi/src/ffi/ffidefault.rs b/third_party/rust/uniffi/src/ffi/ffidefault.rs
new file mode 100644
index 0000000000..f247312be8
--- /dev/null
+++ b/third_party/rust/uniffi/src/ffi/ffidefault.rs
@@ -0,0 +1,52 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! FfiDefault trait
+//!
+//! When we make a FFI call into Rust we always need to return a value, even if that value will be
+//! ignored because we're flagging an exception.  This trait defines what that value is for our
+//! supported FFI types.
+
+use paste::paste;
+
+pub trait FfiDefault {
+    fn ffi_default() -> Self;
+}
+
+// Most types can be handled by delegating to Default
+macro_rules! impl_ffi_default_with_default {
+    ($($T:ty,)+) => { impl_ffi_default_with_default!($($T),+); };
+    ($($T:ty),*) => {
+            $(
+                paste! {
+                    impl FfiDefault for $T {
+                        fn ffi_default() -> Self {
+                            $T::default()
+                        }
+                    }
+                }
+            )*
+    };
+}
+
+impl_ffi_default_with_default! {
+    i8, u8, i16, u16, i32, u32, i64, u64, f32, f64
+}
+
+// Implement FfiDefault for the remaining types
+impl FfiDefault for () {
+    fn ffi_default() {}
+}
+
+impl FfiDefault for *const std::ffi::c_void {
+    fn ffi_default() -> Self {
+        std::ptr::null()
+    }
+}
+
+impl FfiDefault for crate::RustBuffer {
+    fn ffi_default() -> Self {
+        unsafe { Self::from_raw_parts(std::ptr::null_mut(), 0, 0) }
+    }
+}