ndk/native_window: Use release/acquire fns for Drop and Clone

Much like ALooper and AHardwareBuffer the reference counter of
ANativeWindow must be properly incremented on `Clone`, in turn allowing
us to also `_release` the window as soon as it is dropped.

ndk/CHANGELOG.md

@@ -1,5 +1,7 @@
 # Unreleased
 
+- ndk/native_window: Use `release`/`acquire` for `Drop` and `Clone` respectively
+
 # 0.5.0 (2021-11-22)
 
 - **Breaking:** Replace `add_fd_with_callback` `ident` with constant value `ALOOPER_POLL_CALLBACK`,

ndk/src/native_window.rs

@@ -1,17 +1,34 @@
-//! Bindings for `ANativeWindow`
+//! Bindings for [`ffi::ANativeWindow`]
 use std::ptr::NonNull;
 
-#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
+#[derive(Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
 pub struct NativeWindow {
     ptr: NonNull<ffi::ANativeWindow>,
 }
 
 unsafe impl Send for NativeWindow {}
 unsafe impl Sync for NativeWindow {}
 
+impl Drop for NativeWindow {
+    fn drop(&mut self) {
+        unsafe { ffi::ANativeWindow_release(self.ptr.as_ptr()) }
+    }
+}
+
+impl Clone for NativeWindow {
+    fn clone(&self) -> Self {
+        unsafe {
+            ffi::ANativeWindow_acquire(self.ptr.as_ptr());
+            Self { ptr: self.ptr }
+        }
+    }
+}
+
 impl NativeWindow {
+    /// Takes ownership of `ptr`
+    ///
     /// # Safety
-    /// `ptr` must be a valid pointer to an Android `ANativeWindow`.
+    /// `ptr` must be a valid pointer to an Android [`ffi::ANativeWindow`].
     pub unsafe fn from_ptr(ptr: NonNull<ffi::ANativeWindow>) -> Self {
         Self { ptr }
     }