}
namespace detail {
- std::shared_ptr<Timekeeper> getTimekeeperSingleton();
+std::shared_ptr<Timekeeper> getTimekeeperSingleton();
+
+// Guarantees that the stored functor is destructed before the stored promise
+// may be fulfilled. Assumes the stored functor to be noexcept-destructible.
+template <typename T, typename F>
+class CoreCallbackState {
+ public:
+ template <typename FF>
+ CoreCallbackState(Promise<T>&& promise, FF&& func) noexcept(
+ noexcept(F(std::declval<FF>())))
+ : func_(std::forward<FF>(func)), promise_(std::move(promise)) {
+ assert(before_barrier());
+ }
+
+ CoreCallbackState(CoreCallbackState&& that) noexcept(
+ noexcept(F(std::declval<F>()))) {
+ if (that.before_barrier()) {
+ new (&func_) F(std::move(that.func_));
+ promise_ = that.stealPromise();
+ }
+ }
+
+ CoreCallbackState& operator=(CoreCallbackState&&) = delete;
+
+ ~CoreCallbackState() {
+ if (before_barrier()) {
+ stealPromise();
+ }
+ }
+
+ template <typename... Args>
+ auto invoke(Args&&... args) noexcept(
+ noexcept(std::declval<F&&>()(std::declval<Args&&>()...))) {
+ assert(before_barrier());
+ return std::move(func_)(std::forward<Args>(args)...);
+ }
+
+ void setTry(Try<T>&& t) {
+ stealPromise().setTry(std::move(t));
+ }
+
+ void setException(exception_wrapper&& ew) {
+ stealPromise().setException(std::move(ew));
+ }
+
+ Promise<T> stealPromise() noexcept {
+ assert(before_barrier());
+ func_.~F();
+ return std::move(promise_);
+ }
+
+ private:
+ bool before_barrier() const noexcept {
+ return !promise_.isFulfilled();
+ }
+
+ union {
+ F func_;
+ };
+ Promise<T> promise_{detail::EmptyConstruct{}};
+};
+
+template <typename T, typename F>
+inline auto makeCoreCallbackState(Promise<T>&& p, F&& f) noexcept(
+ noexcept(CoreCallbackState<T, _t<std::decay<F>>>(
+ std::declval<Promise<T>&&>(),
+ std::declval<F&&>()))) {
+ return CoreCallbackState<T, _t<std::decay<F>>>(
+ std::move(p), std::forward<F>(f));
+}
}
template <class T>
in the destruction of the Future used to create it.
*/
setCallback_(
- [ func = std::forward<F>(func), pm = std::move(p) ](Try<T> && t) mutable {
+ [state = detail::makeCoreCallbackState(
+ std::move(p), std::forward<F>(func))](Try<T> && t) mutable {
if (!isTry && t.hasException()) {
- pm.setException(std::move(t.exception()));
+ state.setException(std::move(t.exception()));
} else {
- pm.setWith([&]() {
- return std::move(func)(t.template get<isTry, Args>()...);
- });
+ state.setTry(makeTryWith(
+ [&] { return state.invoke(t.template get<isTry, Args>()...); }));
}
});
auto f = p.getFuture();
f.core_->setExecutorNoLock(getExecutor());
- setCallback_([ func = std::forward<F>(func), pm = std::move(p) ](
- Try<T> && t) mutable {
- auto ew = [&] {
- if (!isTry && t.hasException()) {
- return std::move(t.exception());
- } else {
- try {
- auto f2 = std::move(func)(t.template get<isTry, Args>()...);
- // that didn't throw, now we can steal p
- f2.setCallback_([p = std::move(pm)](Try<B> && b) mutable {
- p.setTry(std::move(b));
- });
- return exception_wrapper();
- } catch (const std::exception& e) {
- return exception_wrapper(std::current_exception(), e);
- } catch (...) {
- return exception_wrapper(std::current_exception());
+ setCallback_(
+ [state = detail::makeCoreCallbackState(
+ std::move(p), std::forward<F>(func))](Try<T> && t) mutable {
+ auto ew = [&] {
+ if (!isTry && t.hasException()) {
+ return std::move(t.exception());
+ } else {
+ try {
+ auto f2 = state.invoke(t.template get<isTry, Args>()...);
+ // that didn't throw, now we can steal p
+ f2.setCallback_([p = state.stealPromise()](Try<B> && b) mutable {
+ p.setTry(std::move(b));
+ });
+ return exception_wrapper();
+ } catch (const std::exception& e) {
+ return exception_wrapper(std::current_exception(), e);
+ } catch (...) {
+ return exception_wrapper(std::current_exception());
+ }
+ }
+ }();
+ if (ew) {
+ state.setException(std::move(ew));
}
- }
- }();
- if (ew) {
- pm.setException(std::move(ew));
- }
- });
+ });
return f;
}
auto f = p.getFuture();
setCallback_(
- [ func = std::forward<F>(func), pm = std::move(p) ](Try<T> && t) mutable {
+ [state = detail::makeCoreCallbackState(
+ std::move(p), std::forward<F>(func))](Try<T> && t) mutable {
if (!t.template withException<Exn>([&](Exn& e) {
- pm.setWith([&] { return std::move(func)(e); });
+ state.setTry(makeTryWith([&] { return state.invoke(e); }));
})) {
- pm.setTry(std::move(t));
+ state.setTry(std::move(t));
}
});
Promise<T> p;
auto f = p.getFuture();
- setCallback_([ pm = std::move(p), func = std::forward<F>(func) ](
- Try<T> && t) mutable {
- if (!t.template withException<Exn>([&](Exn& e) {
- auto ew = [&] {
- try {
- auto f2 = std::move(func)(e);
- f2.setCallback_([pm = std::move(pm)](Try<T> && t2) mutable {
- pm.setTry(std::move(t2));
- });
- return exception_wrapper();
- } catch (const std::exception& e2) {
- return exception_wrapper(std::current_exception(), e2);
- } catch (...) {
- return exception_wrapper(std::current_exception());
- }
- }();
- if (ew) {
- pm.setException(std::move(ew));
- }
- })) {
- pm.setTry(std::move(t));
- }
- });
+ setCallback_(
+ [state = detail::makeCoreCallbackState(
+ std::move(p), std::forward<F>(func))](Try<T> && t) mutable {
+ if (!t.template withException<Exn>([&](Exn& e) {
+ auto ew = [&] {
+ try {
+ auto f2 = state.invoke(e);
+ f2.setCallback_([p = state.stealPromise()](
+ Try<T> && t2) mutable { p.setTry(std::move(t2)); });
+ return exception_wrapper();
+ } catch (const std::exception& e2) {
+ return exception_wrapper(std::current_exception(), e2);
+ } catch (...) {
+ return exception_wrapper(std::current_exception());
+ }
+ }();
+ if (ew) {
+ state.setException(std::move(ew));
+ }
+ })) {
+ state.setTry(std::move(t));
+ }
+ });
return f;
}
Promise<T> p;
auto f = p.getFuture();
setCallback_(
- [ pm = std::move(p), func = std::forward<F>(func) ](Try<T> t) mutable {
+ [state = detail::makeCoreCallbackState(
+ std::move(p), std::forward<F>(func))](Try<T> t) mutable {
if (t.hasException()) {
auto ew = [&] {
try {
- auto f2 = std::move(func)(std::move(t.exception()));
- f2.setCallback_([pm = std::move(pm)](Try<T> t2) mutable {
- pm.setTry(std::move(t2));
+ auto f2 = state.invoke(std::move(t.exception()));
+ f2.setCallback_([p = state.stealPromise()](Try<T> t2) mutable {
+ p.setTry(std::move(t2));
});
return exception_wrapper();
} catch (const std::exception& e2) {
}
}();
if (ew) {
- pm.setException(std::move(ew));
+ state.setException(std::move(ew));
}
} else {
- pm.setTry(std::move(t));
+ state.setTry(std::move(t));
}
});
Promise<T> p;
auto f = p.getFuture();
setCallback_(
- [ pm = std::move(p), func = std::forward<F>(func) ](Try<T> t) mutable {
+ [state = detail::makeCoreCallbackState(
+ std::move(p), std::forward<F>(func))](Try<T> t) mutable {
if (t.hasException()) {
- pm.setWith([&] { return std::move(func)(std::move(t.exception())); });
+ state.setTry(makeTryWith(
+ [&] { return state.invoke(std::move(t.exception())); }));
} else {
- pm.setTry(std::move(t));
+ state.setTry(std::move(t));
}
});