Add Rust wrapper around native_handle_t.
Bug: 359100544
Test: atest libnativewindow_rs-internal_test
Change-Id: Ia4082c7eb2682a58beb4757ac332a8af840f4455
diff --git a/libs/nativewindow/rust/src/handle.rs b/libs/nativewindow/rust/src/handle.rs
new file mode 100644
index 0000000..a3a9dc6
--- /dev/null
+++ b/libs/nativewindow/rust/src/handle.rs
@@ -0,0 +1,92 @@
+// Copyright (C) 2024 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::{mem::forget, ptr::NonNull};
+
+/// Rust wrapper around `native_handle_t`.
+///
+/// This owns the `native_handle_t` and its file descriptors, and will close them and free it when
+/// it is dropped.
+#[derive(Debug)]
+pub struct NativeHandle(NonNull<ffi::native_handle_t>);
+
+impl NativeHandle {
+ /// Wraps a raw `native_handle_t` pointer, taking ownership of it.
+ ///
+ /// # Safety
+ ///
+ /// `native_handle` must be a valid pointer to a `native_handle_t`, and must not be used
+ /// anywhere else after calling this method.
+ pub unsafe fn from_raw(native_handle: NonNull<ffi::native_handle_t>) -> Self {
+ Self(native_handle)
+ }
+
+ /// Creates a new `NativeHandle` wrapping a clone of the given `native_handle_t` pointer.
+ ///
+ /// Unlike [`from_raw`](Self::from_raw) this doesn't take ownership of the pointer passed in, so
+ /// the caller remains responsible for closing and freeing it.
+ ///
+ /// # Safety
+ ///
+ /// `native_handle` must be a valid pointer to a `native_handle_t`.
+ pub unsafe fn clone_from_raw(native_handle: NonNull<ffi::native_handle_t>) -> Option<Self> {
+ // SAFETY: The caller promised that `native_handle` was valid.
+ let cloned = unsafe { ffi::native_handle_clone(native_handle.as_ptr()) };
+ NonNull::new(cloned).map(Self)
+ }
+
+ /// Returns a raw pointer to the wrapped `native_handle_t`.
+ ///
+ /// This is only valid as long as this `NativeHandle` exists, so shouldn't be stored. It mustn't
+ /// be closed or deleted.
+ pub fn as_raw(&self) -> NonNull<ffi::native_handle_t> {
+ self.0
+ }
+
+ /// Turns the `NativeHandle` into a raw `native_handle_t`.
+ ///
+ /// The caller takes ownership of the `native_handle_t` and its file descriptors, so is
+ /// responsible for closing and freeing it.
+ pub fn into_raw(self) -> NonNull<ffi::native_handle_t> {
+ let raw = self.0;
+ forget(self);
+ raw
+ }
+}
+
+impl Clone for NativeHandle {
+ fn clone(&self) -> Self {
+ // SAFETY: Our wrapped `native_handle_t` pointer is always valid.
+ unsafe { Self::clone_from_raw(self.0) }.expect("native_handle_clone returned null")
+ }
+}
+
+impl Drop for NativeHandle {
+ fn drop(&mut self) {
+ // SAFETY: Our wrapped `native_handle_t` pointer is always valid, and it won't be accessed
+ // after this because we own it and are being dropped.
+ unsafe {
+ assert_eq!(ffi::native_handle_close(self.0.as_ptr()), 0);
+ assert_eq!(ffi::native_handle_delete(self.0.as_ptr()), 0);
+ }
+ }
+}
+
+// SAFETY: `NativeHandle` owns the `native_handle_t`, which just contains some integers and file
+// descriptors, which aren't tied to any particular thread.
+unsafe impl Send for NativeHandle {}
+
+// SAFETY: A `NativeHandle` can be used from different threads simultaneously, as is is just
+// integers and file descriptors.
+unsafe impl Sync for NativeHandle {}
diff --git a/libs/nativewindow/rust/src/lib.rs b/libs/nativewindow/rust/src/lib.rs
index dc3f51f..ffde137 100644
--- a/libs/nativewindow/rust/src/lib.rs
+++ b/libs/nativewindow/rust/src/lib.rs
@@ -16,7 +16,10 @@
extern crate nativewindow_bindgen as ffi;
+mod handle;
mod surface;
+
+pub use handle::NativeHandle;
pub use surface::Surface;
pub use ffi::{AHardwareBuffer_Format, AHardwareBuffer_UsageFlags};