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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
#include "Natives.h"
#include "mozilla/MozPromise.h"
namespace mozilla::jni {
namespace details {
/**
* When a NativeWeakPtr is detached from its owning Java object, the calling
* thread invokes the implementation's OnWeakNonIntrusiveDetach to perform
* cleanup. We complete the remainder of the cleanup sequence on the Gecko
* main thread by expecting OnWeakNonIntrusiveDetach implementations to invoke
* this Runnable before exiting. It will move itself to the main thread if it
* is not already there.
*/
template <typename NativeImpl>
class NativeWeakPtrDetachRunnable final : public Runnable {
public:
NativeWeakPtrDetachRunnable(
already_AddRefed<detail::NativeWeakPtrControlBlock<NativeImpl>> aCtlBlock,
const Object::LocalRef& aOwner,
typename NativeWeakPtrControlBlockStorageTraits<NativeImpl>::Type
aNativeImpl)
: Runnable("mozilla::jni::detail::NativeWeakPtrDetachRunnable"),
mCtlBlock(aCtlBlock),
mOwner(aOwner),
mNativeImpl(std::move(aNativeImpl)),
mHasRun(false) {
MOZ_RELEASE_ASSERT(!!mCtlBlock);
MOZ_RELEASE_ASSERT(!!mNativeImpl);
}
NS_INLINE_DECL_REFCOUNTING_INHERITED(NativeWeakPtrDetachRunnable, Runnable)
NS_IMETHOD Run() override {
mHasRun = true;
if (!NS_IsMainThread()) {
NS_DispatchToMainThread(this);
return NS_OK;
}
// Get the owner object's native implementation
auto owner = ToLocalRef(mOwner);
auto attachedNativeImpl = NativePtrTraits<NativeImpl>::Get(owner);
MOZ_RELEASE_ASSERT(!!attachedNativeImpl);
// NativePtrTraits::ClearFinish cleans out the JNIObject's handle, which
// obviously we don't want to attempt unless that handle still points to
// our native implementation.
if (attachedNativeImpl->IsSame(mCtlBlock)) {
NativePtrTraits<NativeImpl>::ClearFinish(owner);
}
// Now we destroy that native object.
mNativeImpl = nullptr;
mHolder.Resolve(true, __func__);
return NS_OK;
}
RefPtr<DetachPromise> GetPromise() { return mHolder.Ensure(__func__); }
private:
~NativeWeakPtrDetachRunnable() {
// Guard against somebody forgetting to call this runnable.
MOZ_RELEASE_ASSERT(mHasRun, "You must run/dispatch this runnable!");
}
private:
RefPtr<detail::NativeWeakPtrControlBlock<NativeImpl>> mCtlBlock;
Object::GlobalRef mOwner;
MozPromiseHolder<DetachPromise> mHolder;
typename NativeWeakPtrControlBlockStorageTraits<NativeImpl>::Type mNativeImpl;
bool mHasRun;
};
} // namespace details
template <typename NativeImpl>
RefPtr<DetachPromise> NativeWeakPtr<NativeImpl>::Detach() {
if (!IsAttached()) {
// Never attached to begin with; no-op
return DetachPromise::CreateAndResolve(true, __func__);
}
auto native = mCtlBlock->Clear();
if (!native) {
// Detach already in progress
return DetachPromise::CreateAndResolve(true, __func__);
}
Object::LocalRef owner(mCtlBlock->GetJavaOwner());
MOZ_RELEASE_ASSERT(!!owner);
// Save the raw pointer before we move native into the runnable so that we
// may call OnWeakNonIntrusiveDetach on it even after moving native into
// the runnable.
NativeImpl* rawImpl =
detail::NativeWeakPtrControlBlock<NativeImpl>::StorageTraits::AsRaw(
native);
RefPtr<details::NativeWeakPtrDetachRunnable<NativeImpl>> runnable =
new details::NativeWeakPtrDetachRunnable<NativeImpl>(
mCtlBlock.forget(), owner, std::move(native));
RefPtr<DetachPromise> promise = runnable->GetPromise();
rawImpl->OnWeakNonIntrusiveDetach(runnable.forget());
return promise;
}
} // namespace mozilla::jni