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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=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
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
#ifndef TESTING_GTEST_MOZILLA_WAITFOR_H_
#define TESTING_GTEST_MOZILLA_WAITFOR_H_
#include "MediaEventSource.h"
#include "mozilla/media/MediaUtils.h"
#include "mozilla/Maybe.h"
#include "mozilla/MozPromise.h"
#include "mozilla/SpinEventLoopUntil.h"
namespace mozilla {
/**
* Waits for an occurrence of aEvent on the current thread (by blocking it,
* except tasks added to the event loop may run) and returns the event's
* templated value, if it's non-void.
*
* The caller must be wary of eventloop issues, in
* particular cases where we rely on a stable state runnable, but there is never
* a task to trigger stable state. In such cases it is the responsibility of the
* caller to create the needed tasks, as JS would. A noteworthy API that relies
* on stable state is MediaTrackGraph::GetInstance.
*/
template <ListenerPolicy Lp, typename First, typename... Rest>
inline auto WaitFor(MediaEventSourceImpl<Lp, First, Rest...>& aEvent) {
constexpr size_t num_params = 1 + sizeof...(Rest);
using Storage =
std::conditional_t<num_params == 1, First, std::tuple<First, Rest...>>;
Maybe<Storage> value;
if constexpr (Lp == ListenerPolicy::NonExclusive) {
MediaEventListener listener =
aEvent.Connect(AbstractThread::GetCurrent(),
[&value](const First& aFirst, const Rest&... aRest) {
if constexpr (num_params == 1) {
value = Some(aFirst);
} else {
value = Some<Storage>({aFirst, aRest...});
}
});
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitFor(MediaEventSource<T>& aEvent)"_ns,
[&] { return value.isSome(); });
listener.Disconnect();
return value.value();
} else {
MediaEventListener listener = aEvent.Connect(
AbstractThread::GetCurrent(),
[&value](First&& aFirst, Rest&&... aRest) {
if constexpr (num_params == 1) {
value = Some<Storage>(std::forward<First>(aFirst));
} else {
value = Some<Storage>(
{std::forward<First>(aFirst), std::forward<Rest...>(aRest...)});
}
});
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitFor(MediaEventSource<T>& aEvent)"_ns,
[&] { return value.isSome(); });
listener.Disconnect();
return value.value();
}
}
/**
* Specialization of WaitFor<T> for void.
*/
template <ListenerPolicy Lp>
inline void WaitFor(MediaEventSourceImpl<Lp, void>& aEvent) {
bool done = false;
MediaEventListener listener =
aEvent.Connect(AbstractThread::GetCurrent(), [&] { done = true; });
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitFor(MediaEventSource<void>& aEvent)"_ns, [&] { return done; });
listener.Disconnect();
}
/**
* Variant of WaitFor that spins the event loop until a MozPromise has either
* been resolved or rejected. Result accepts R and E only if their types
* differ. Consider also WaitForResolve() and WaitForReject(), which are
* suitable even when resolve and reject types are the same.
*/
template <typename R, typename E, bool Exc>
inline Result<R, E> WaitFor(const RefPtr<MozPromise<R, E, Exc>>& aPromise) {
Maybe<R> success;
Maybe<E> error;
// Use r-value reference for exclusive promises to support move-only types.
using RRef = typename std::conditional_t<Exc, R&&, const R&>;
using ERef = typename std::conditional_t<Exc, E&&, const E&>;
aPromise->Then(
GetCurrentSerialEventTarget(), __func__,
[&](RRef aResult) { success.emplace(std::forward<RRef>(aResult)); },
[&](ERef aError) { error.emplace(std::forward<ERef>(aError)); });
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitFor(const RefPtr<MozPromise<R, E, Exc>>& aPromise)"_ns,
[&] { return success.isSome() || error.isSome(); });
if (success.isSome()) {
return success.extract();
}
return Err(error.extract());
}
/**
* Variation on WaitFor that spins the event loop until a MozPromise has been
* resolved.
*/
template <typename R, typename E, bool Exc>
inline R WaitForResolve(const RefPtr<MozPromise<R, E, Exc>>& aPromise) {
Maybe<R> success;
// Use r-value reference for exclusive promises to support move-only types.
using RRef = typename std::conditional_t<Exc, R&&, const R&>;
using ERef = typename std::conditional_t<Exc, E&&, const E&>;
aPromise->Then(
GetCurrentSerialEventTarget(), __func__,
[&](RRef aResult) { success.emplace(std::forward<RRef>(aResult)); },
[&](ERef aError) { MOZ_CRASH("rejection was not expected"); });
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitForResolve(const RefPtr<MozPromise<R, E, Exc>>& aPromise)"_ns,
[&] { return success.isSome(); });
return success.extract();
}
/**
* Variation on WaitFor that spins the event loop until a MozPromise has been
* rejected.
*/
template <typename R, typename E, bool Exc>
inline E WaitForReject(const RefPtr<MozPromise<R, E, Exc>>& aPromise) {
Maybe<E> error;
// Use r-value reference for exclusive promises to support move-only types.
using RRef = typename std::conditional_t<Exc, R&&, const R&>;
using ERef = typename std::conditional_t<Exc, E&&, const E&>;
aPromise->Then(
GetCurrentSerialEventTarget(), __func__,
[&](RRef aResult) { MOZ_CRASH("resolution was not expected"); },
[&](ERef aError) { error.emplace(std::forward<ERef>(aError)); });
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitForReject(const RefPtr<MozPromise<R, E, Exc>>& aPromise)"_ns,
[&] { return error.isSome(); });
return error.extract();
}
/**
* A variation of WaitFor that takes a callback to be called each time aEvent is
* raised. Blocks the caller until the callback function returns true.
*/
template <ListenerPolicy Lp, typename... Args, typename CallbackFunction>
inline void WaitUntil(MediaEventSourceImpl<Lp, Args...>& aEvent,
CallbackFunction&& aF) {
bool done = false;
MediaEventListener listener =
aEvent.Connect(AbstractThread::GetCurrent(), [&](Args... aValue) {
if (!done) {
done = aF(std::forward<Args>(aValue)...);
}
});
SpinEventLoopUntil<ProcessFailureBehavior::IgnoreAndContinue>(
"WaitUntil(MediaEventSource<Args...>& aEvent, CallbackFunction&& aF)"_ns,
[&] { return done; });
listener.Disconnect();
}
template <typename... Args>
using TakeNPromise = MozPromise<std::vector<std::tuple<Args...>>, bool, true>;
template <ListenerPolicy Lp, typename... Args>
inline auto TakeN(MediaEventSourceImpl<Lp, Args...>& aEvent, size_t aN)
-> RefPtr<TakeNPromise<Args...>> {
using Storage = std::vector<std::tuple<Args...>>;
using Promise = TakeNPromise<Args...>;
using Holder = media::Refcountable<MozPromiseHolder<Promise>>;
using Values = media::Refcountable<Storage>;
using Listener = media::Refcountable<MediaEventListener>;
auto values = MakeRefPtr<Values>();
values->reserve(aN);
auto listener = MakeRefPtr<Listener>();
auto holder = MakeRefPtr<Holder>();
*listener = aEvent.Connect(AbstractThread::GetCurrent(),
[values, listener, aN, holder](Args... aValue) {
values->push_back({aValue...});
if (values->size() == aN) {
listener->Disconnect();
holder->Resolve(std::move(*values),
"TakeN listener callback");
}
});
return holder->Ensure(__func__);
}
using TakeNVoidPromise = MozPromise<size_t, bool, true>;
template <ListenerPolicy Lp>
inline auto TakeN(MediaEventSourceImpl<Lp, void>& aEvent, size_t aN)
-> RefPtr<TakeNVoidPromise> {
using Storage = Maybe<size_t>;
using Promise = TakeNVoidPromise;
using Holder = media::Refcountable<MozPromiseHolder<Promise>>;
using Values = media::Refcountable<Storage>;
using Listener = media::Refcountable<MediaEventListener>;
auto values = MakeRefPtr<Values>();
*values = Some(0);
auto listener = MakeRefPtr<Listener>();
auto holder = MakeRefPtr<Holder>();
*listener = aEvent.Connect(
AbstractThread::GetCurrent(), [values, listener, aN, holder]() {
if (++(values->ref()) == aN) {
listener->Disconnect();
holder->Resolve(**values, "TakeN (void) listener callback");
}
});
return holder->Ensure(__func__);
}
/**
* Helper that, given that canonicals have just been updated on the current
* thread, will block its execution until mirrors and their watchers have
* executed on aTarget.
*/
inline void WaitForMirrors(const RefPtr<nsISerialEventTarget>& aTarget) {
(void)WaitFor(InvokeAsync(aTarget, __func__, [] {
return GenericPromise::CreateAndResolve(true, "WaitForMirrors resolver");
}));
}
/**
* Short form of WaitForMirrors that assumes mirrors are on the current thread
* (like canonicals).
*/
inline void WaitForMirrors() { WaitForMirrors(GetCurrentSerialEventTarget()); }
} // namespace mozilla
#endif // TESTING_GTEST_MOZILLA_WAITFOR_H_
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