Add methods to convert between HardwareBuffer and native handle.
Bug: 359100544
Test: atest libnativewindow_rs-internal_test
Change-Id: I7db2cc091aae36ee4b62f3925504a634feb6daac
diff --git a/libs/nativewindow/rust/src/lib.rs b/libs/nativewindow/rust/src/lib.rs
index ffde137..54dad04 100644
--- a/libs/nativewindow/rust/src/lib.rs
+++ b/libs/nativewindow/rust/src/lib.rs
@@ -106,6 +106,50 @@
}
}
+ /// Creates a `HardwareBuffer` from a native handle.
+ ///
+ /// The native handle is cloned, so this doesn't take ownership of the original handle passed
+ /// in.
+ pub fn create_from_handle(
+ handle: &NativeHandle,
+ buffer_desc: &ffi::AHardwareBuffer_Desc,
+ ) -> Result<Self, StatusCode> {
+ let mut buffer = ptr::null_mut();
+ // SAFETY: The caller guarantees that `handle` is valid, and the buffer pointer is valid
+ // because it comes from a reference. The method we pass means that
+ // `AHardwareBuffer_createFromHandle` will clone the handle rather than taking ownership of
+ // it.
+ let status = unsafe {
+ ffi::AHardwareBuffer_createFromHandle(
+ buffer_desc,
+ handle.as_raw().as_ptr(),
+ ffi::CreateFromHandleMethod_AHARDWAREBUFFER_CREATE_FROM_HANDLE_METHOD_CLONE
+ .try_into()
+ .unwrap(),
+ &mut buffer,
+ )
+ };
+ status_result(status)?;
+ Ok(Self(NonNull::new(buffer).expect("Allocated AHardwareBuffer was null")))
+ }
+
+ /// Returns a clone of the native handle of the buffer.
+ ///
+ /// Returns `None` if the operation fails for any reason.
+ pub fn cloned_native_handle(&self) -> Option<NativeHandle> {
+ // SAFETY: The AHardwareBuffer pointer we pass is guaranteed to be non-null and valid
+ // because it must have been allocated by `AHardwareBuffer_allocate`,
+ // `AHardwareBuffer_readFromParcel` or the caller of `from_raw` and we have not yet
+ // released it.
+ let native_handle = unsafe { ffi::AHardwareBuffer_getNativeHandle(self.0.as_ptr()) };
+ NonNull::new(native_handle.cast_mut()).and_then(|native_handle| {
+ // SAFETY: `AHardwareBuffer_getNativeHandle` should have returned a valid pointer which
+ // is valid at least as long as the buffer is, and `clone_from_raw` clones it rather
+ // than taking ownership of it so the original `native_handle` isn't stored.
+ unsafe { NativeHandle::clone_from_raw(native_handle) }
+ })
+ }
+
/// Adopts the given raw pointer and wraps it in a Rust HardwareBuffer.
///
/// # Safety
@@ -393,4 +437,34 @@
assert_eq!(remade_buffer, buffer2);
}
+
+ #[test]
+ fn native_handle_and_back() {
+ let buffer = HardwareBuffer::new(
+ 1024,
+ 512,
+ 1,
+ AHardwareBuffer_Format::AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM,
+ AHardwareBuffer_UsageFlags::AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN,
+ )
+ .expect("Buffer with some basic parameters was not created successfully");
+
+ let native_handle =
+ buffer.cloned_native_handle().expect("Failed to get native handle for buffer");
+ let buffer_desc = ffi::AHardwareBuffer_Desc {
+ width: 1024,
+ height: 512,
+ layers: 1,
+ format: AHardwareBuffer_Format::AHARDWAREBUFFER_FORMAT_R8G8B8A8_UNORM,
+ usage: AHardwareBuffer_UsageFlags::AHARDWAREBUFFER_USAGE_CPU_READ_OFTEN.0,
+ stride: 1024,
+ rfu0: 0,
+ rfu1: 0,
+ };
+ let buffer2 = HardwareBuffer::create_from_handle(&native_handle, &buffer_desc)
+ .expect("Failed to create buffer from native handle");
+
+ assert_eq!(buffer.description(), buffer_desc);
+ assert_eq!(buffer2.description(), buffer_desc);
+ }
}