Commit 646be295 authored by Anton Lunov's avatar Anton Lunov Committed by Facebook Github Bot

Revert D4982969: [Folly] Destroy promise/future callback functions before waking waiters

Summary: This reverts commit 71134c1657bdd4c38c12d8ca17f8335ef4c27352

Differential Revision: D4982969

fbshipit-source-id: fc1e766a5fd03fbd02c345904c3c6587013f38d5
parent e8d25954
......@@ -48,76 +48,7 @@ typedef folly::Baton<> FutureBatonType;
}
namespace detail {
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));
}
std::shared_ptr<Timekeeper> getTimekeeperSingleton();
}
template <class T>
......@@ -229,13 +160,13 @@ Future<T>::thenImplementation(F&& func, detail::argResult<isTry, F, Args...>) {
in the destruction of the Future used to create it.
*/
setCallback_(
[state = detail::makeCoreCallbackState(
std::move(p), std::forward<F>(func))](Try<T> && t) mutable {
[ func = std::forward<F>(func), pm = std::move(p) ](Try<T> && t) mutable {
if (!isTry && t.hasException()) {
state.setException(std::move(t.exception()));
pm.setException(std::move(t.exception()));
} else {
state.setTry(makeTryWith(
[&] { return state.invoke(t.template get<isTry, Args>()...); }));
pm.setWith([&]() {
return std::move(func)(t.template get<isTry, Args>()...);
});
}
});
......@@ -260,31 +191,30 @@ Future<T>::thenImplementation(F&& func, detail::argResult<isTry, F, Args...>) {
auto f = p.getFuture();
f.core_->setExecutorNoLock(getExecutor());
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));
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());
}
});
}
}();
if (ew) {
pm.setException(std::move(ew));
}
});
return f;
}
......@@ -336,12 +266,11 @@ Future<T>::onError(F&& func) {
auto f = p.getFuture();
setCallback_(
[state = detail::makeCoreCallbackState(
std::move(p), std::forward<F>(func))](Try<T> && t) mutable {
[ func = std::forward<F>(func), pm = std::move(p) ](Try<T> && t) mutable {
if (!t.template withException<Exn>([&](Exn& e) {
state.setTry(makeTryWith([&] { return state.invoke(e); }));
pm.setWith([&] { return std::move(func)(e); });
})) {
state.setTry(std::move(t));
pm.setTry(std::move(t));
}
});
......@@ -364,29 +293,29 @@ Future<T>::onError(F&& func) {
Promise<T> p;
auto f = p.getFuture();
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));
}
});
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));
}
});
return f;
}
......@@ -420,14 +349,13 @@ Future<T>::onError(F&& func) {
Promise<T> p;
auto f = p.getFuture();
setCallback_(
[state = detail::makeCoreCallbackState(
std::move(p), std::forward<F>(func))](Try<T> t) mutable {
[ pm = std::move(p), func = std::forward<F>(func) ](Try<T> t) mutable {
if (t.hasException()) {
auto ew = [&] {
try {
auto f2 = state.invoke(std::move(t.exception()));
f2.setCallback_([p = state.stealPromise()](Try<T> t2) mutable {
p.setTry(std::move(t2));
auto f2 = std::move(func)(std::move(t.exception()));
f2.setCallback_([pm = std::move(pm)](Try<T> t2) mutable {
pm.setTry(std::move(t2));
});
return exception_wrapper();
} catch (const std::exception& e2) {
......@@ -437,10 +365,10 @@ Future<T>::onError(F&& func) {
}
}();
if (ew) {
state.setException(std::move(ew));
pm.setException(std::move(ew));
}
} else {
state.setTry(std::move(t));
pm.setTry(std::move(t));
}
});
......@@ -462,13 +390,11 @@ Future<T>::onError(F&& func) {
Promise<T> p;
auto f = p.getFuture();
setCallback_(
[state = detail::makeCoreCallbackState(
std::move(p), std::forward<F>(func))](Try<T> t) mutable {
[ pm = std::move(p), func = std::forward<F>(func) ](Try<T> t) mutable {
if (t.hasException()) {
state.setTry(makeTryWith(
[&] { return state.invoke(std::move(t.exception())); }));
pm.setWith([&] { return std::move(func)(std::move(t.exception())); });
} else {
state.setTry(std::move(t));
pm.setTry(std::move(t));
}
});
......
......@@ -59,10 +59,6 @@ void Promise<T>::throwIfRetrieved() {
}
}
template <class T>
Promise<T>::Promise(detail::EmptyConstruct) noexcept
: retrieved_(false), core_(nullptr) {}
template <class T>
Promise<T>::~Promise() {
detach();
......
......@@ -25,12 +25,6 @@ namespace folly {
// forward declaration
template <class T> class Future;
namespace detail {
struct EmptyConstruct {};
template <typename T, typename F>
class CoreCallbackState;
}
template <class T>
class Promise {
public:
......@@ -104,8 +98,6 @@ class Promise {
private:
typedef typename Future<T>::corePtr corePtr;
template <class> friend class Future;
template <class, class>
friend class detail::CoreCallbackState;
// Whether the Future has been retrieved (a one-time operation).
bool retrieved_;
......@@ -113,8 +105,6 @@ class Promise {
// shared core state object
corePtr core_;
explicit Promise(detail::EmptyConstruct) noexcept;
void throwIfFulfilled();
void throwIfRetrieved();
void detach();
......
/*
* Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <folly/futures/Future.h>
#include <thread>
#include <folly/futures/test/TestExecutor.h>
#include <folly/portability/GTest.h>
using namespace folly;
namespace {
/***
* The basic premise is to check that the callback passed to then or onError
* is destructed before wait returns on the resulting future.
*
* The approach is to use callbacks where the destructor sleeps 500ms and then
* mutates a counter allocated on the caller stack. The caller checks the
* counter immediately after calling wait. Were the callback not destructed
* before wait returns, then we would very likely see an unchanged counter just
* after wait returns. But if, as we expect, the callback were destructed
* before wait returns, then we must be guaranteed to see a mutated counter
* just after wait returns.
*
* Note that the failure condition is not strictly guaranteed under load. :(
*/
class CallbackLifetimeTest : public testing::Test {
public:
using CounterPtr = std::unique_ptr<size_t>;
static bool kRaiseWillThrow() {
return true;
}
static constexpr auto kDelay() {
return std::chrono::milliseconds(500);
}
auto mkC() {
return std::make_unique<size_t>(0);
}
auto mkCGuard(CounterPtr& ptr) {
return makeGuard([&] {
/* sleep override */ std::this_thread::sleep_for(kDelay());
++*ptr;
});
}
static void raise() {
if (kRaiseWillThrow()) { // to avoid marking [[noreturn]]
throw std::runtime_error("raise");
}
}
static Future<Unit> raiseFut() {
raise();
return makeFuture();
}
TestExecutor executor{2}; // need at least 2 threads for internal futures
};
}
TEST_F(CallbackLifetimeTest, thenReturnsValue) {
auto c = mkC();
via(&executor).then([_ = mkCGuard(c)]{}).wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, thenReturnsValueThrows) {
auto c = mkC();
via(&executor).then([_ = mkCGuard(c)] { raise(); }).wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, thenReturnsFuture) {
auto c = mkC();
via(&executor).then([_ = mkCGuard(c)] { return makeFuture(); }).wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, thenReturnsFutureThrows) {
auto c = mkC();
via(&executor).then([_ = mkCGuard(c)] { return raiseFut(); }).wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsValueMatch) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::exception&){})
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsValueMatchThrows) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::exception&) { raise(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsValueWrong) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::logic_error&){})
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsValueWrongThrows) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::logic_error&) { raise(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsFutureMatch) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::exception&) { return makeFuture(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsFutureMatchThrows) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::exception&) { return raiseFut(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsFutureWrong) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::logic_error&) { return makeFuture(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesExnReturnsFutureWrongThrows) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](std::logic_error&) { return raiseFut(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesWrapReturnsValue) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](exception_wrapper &&){})
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesWrapReturnsValueThrows) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](exception_wrapper &&) { raise(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesWrapReturnsFuture) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](exception_wrapper &&) { return makeFuture(); })
.wait();
EXPECT_EQ(1, *c);
}
TEST_F(CallbackLifetimeTest, onErrorTakesWrapReturnsFutureThrows) {
auto c = mkC();
via(&executor)
.then(raise)
.onError([_ = mkCGuard(c)](exception_wrapper &&) { return raiseFut(); })
.wait();
EXPECT_EQ(1, *c);
}
......@@ -262,7 +262,6 @@ unit_test_LDADD = libfollytestmain.la
TESTS += unit_test
futures_test_SOURCES = \
../futures/test/CallbackLifetimeTest.cpp \
../futures/test/CollectTest.cpp \
../futures/test/ContextTest.cpp \
../futures/test/CoreTest.cpp \
......
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