[shared-buffer] Implement Send + Sync
- Implement Send + Sync for SharedBuffer, SharedBufferSlice, and
SharedBufferSliceMut
Test: No tests since this is a memory safety property. Memory safety
argument provided in comment.
SEC-84
Change-Id: I221837958dd6b2d79f8dab460af7a826175d5eaf
diff --git a/public/rust/shared-buffer/src/lib.rs b/public/rust/shared-buffer/src/lib.rs
index 70183c5..3f9bb23 100644
--- a/public/rust/shared-buffer/src/lib.rs
+++ b/public/rust/shared-buffer/src/lib.rs
@@ -956,6 +956,22 @@
}
}
+// Send and Sync implementations. Send and Sync are definitely safe since
+// SharedBufferXXX are all written under the assumption that a remote process is
+// concurrently modifying the memory. However, we aim to provide a Rust-like API
+// with lifetimes and an immutable/mutable distinction, so the real question is
+// whether Send and Sync make sense by analogy to normal Rust types. Insofar as
+// SharedBuffer is analogous to [u8], SharedBufferSlice is analogous to &[u8],
+// and SharedBufferSliceMut is analogous to &mut [u8], the answer is yes - all
+// of those types implement both Send and Sync.
+
+unsafe impl Send for SharedBuffer {}
+unsafe impl Sync for SharedBuffer {}
+unsafe impl<'a> Send for SharedBufferSlice<'a> {}
+unsafe impl<'a> Sync for SharedBufferSlice<'a> {}
+unsafe impl<'a> Send for SharedBufferSliceMut<'a> {}
+unsafe impl<'a> Sync for SharedBufferSliceMut<'a> {}
+
#[cfg(test)]
mod tests {
use core::mem;
