Ensure AndroidAppWaker owns an ALooper reference#227
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This ensures we call `ALooper_acquire` before `create_waker()` wraps the Looper pointer with `AndroidAppWaker` and it also ensures that `::clone()` and `::drop()` call `ALooper_acquire()` and `ALooper_release()` respectively. Contrary to what the comment for the `looper` member said previously, it was not safe to assume that the application's looper pointer had a `'static` lifetime. The looper pointer would only be valid up until `android_main` returns, but unlike a traditional `main()` function an `android_main()` runs with respect to an `Activity` lifecycle and not a process lifecycle. It's technically possible for `android_main()` to return (at which point any looper stored in `'static` storage would have previously become an invalid pointer) and then JNI could be used to re-enter Rust and potentially try and dereference that invalid pointer. This adds a shared implementation of `AndroidAppWaker` to `src/waker.rs` instead of having each backend implement `AndroidAppWaker`. Fixes: #226
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This ensures we call
ALooper_acquirebeforecreate_waker()wraps the Looper pointer withAndroidAppWakerand it also ensures that::clone()and::drop()callALooper_acquire()andALooper_release()respectively.Contrary to what the comment for the
loopermember said previously, it was not safe to assume that the application's looper pointer had a'staticlifetime.The looper pointer would only be valid up until
android_mainreturns, but unlike a traditionalmain()function anandroid_main()runs with respect to anActivitylifecycle and not a process lifecycle.It's technically possible for
android_main()to return (at which point any looper stored in'staticstorage would have previously become an invalid pointer) and then JNI could be used to re-enter Rust and potentially try and dereference that invalid pointer.This adds a shared implementation of
AndroidAppWakertosrc/waker.rsinstead of having each backend implementAndroidAppWaker.Fixes: #226