1 files changed, 46 insertions, 0 deletions
diff --git a/third_party/rust/uniffi_core/src/ffi/handle.rs b/third_party/rust/uniffi_core/src/ffi/handle.rs
new file mode 100644
index 0000000000..8ee2f46c35
--- /dev/null
+++ b/third_party/rust/uniffi_core/src/ffi/handle.rs
@@ -0,0 +1,46 @@
+/* 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/. */
+
+/// Object handle
+///
+/// Handles opaque `u64` values used to pass objects across the FFI, both for objects implemented in
+/// Rust and ones implemented in the foreign language.
+///
+/// Rust handles are generated by leaking a raw pointer
+/// Foreign handles are generated with a handle map that only generates odd values.
+/// For all currently supported architectures and hopefully any ones we add in the future:
+/// * 0 is an invalid value.
+/// * The lowest bit will always be set for foreign handles and never set for Rust ones (since the
+///   leaked pointer will be aligned).
+///
+/// Rust handles are mainly managed is through the [crate::HandleAlloc] trait.
+#[derive(Copy, Clone, Default, Debug, PartialEq, Eq)]
+#[repr(transparent)]
+pub struct Handle(u64);
+
+impl Handle {
+    pub fn from_pointer<T>(ptr: *const T) -> Self {
+        Self(ptr as u64)
+    }
+
+    pub fn as_pointer<T>(&self) -> *const T {
+        self.0 as *const T
+    }
+
+    pub fn from_raw(raw: u64) -> Option<Self> {
+        if raw == 0 {
+            None
+        } else {
+            Some(Self(raw))
+        }
+    }
+
+    pub fn from_raw_unchecked(raw: u64) -> Self {
+        Self(raw)
+    }
+
+    pub fn as_raw(&self) -> u64 {
+        self.0
+    }
+}