138 lines
4.1 KiB
C++
138 lines
4.1 KiB
C++
/*
|
|
* Copyright 2004 The WebRTC Project Authors. All rights reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
#ifndef RTC_BASE_EVENT_H_
|
|
#define RTC_BASE_EVENT_H_
|
|
|
|
#include "api/units/time_delta.h"
|
|
|
|
#if defined(WEBRTC_WIN)
|
|
#include <windows.h>
|
|
#elif defined(WEBRTC_POSIX)
|
|
#include <pthread.h>
|
|
#else
|
|
#error "Must define either WEBRTC_WIN or WEBRTC_POSIX."
|
|
#endif
|
|
|
|
#include "rtc_base/synchronization/yield_policy.h"
|
|
|
|
namespace rtc {
|
|
|
|
// RTC_DISALLOW_WAIT() utility
|
|
//
|
|
// Sets a stack-scoped flag that disallows use of `rtc::Event::Wait` by means
|
|
// of raising a DCHECK when a call to `rtc::Event::Wait()` is made..
|
|
// This is useful to guard synchronization-free scopes against regressions.
|
|
//
|
|
// Example of what this would catch (`ScopeToProtect` calls `Foo`):
|
|
//
|
|
// void Foo(TaskQueue* tq) {
|
|
// Event event;
|
|
// tq->PostTask([&event]() {
|
|
// event.Set();
|
|
// });
|
|
// event.Wait(Event::kForever); // <- Will trigger a DCHECK.
|
|
// }
|
|
//
|
|
// void ScopeToProtect() {
|
|
// TaskQueue* tq = GetSomeTaskQueue();
|
|
// RTC_DISALLOW_WAIT(); // Policy takes effect.
|
|
// Foo(tq);
|
|
// }
|
|
//
|
|
#if RTC_DCHECK_IS_ON
|
|
#define RTC_DISALLOW_WAIT() ScopedDisallowWait disallow_wait_##__LINE__
|
|
#else
|
|
#define RTC_DISALLOW_WAIT()
|
|
#endif
|
|
|
|
class Event {
|
|
public:
|
|
// TODO(bugs.webrtc.org/14366): Consider removing this redundant alias.
|
|
static constexpr webrtc::TimeDelta kForever =
|
|
webrtc::TimeDelta::PlusInfinity();
|
|
|
|
Event();
|
|
Event(bool manual_reset, bool initially_signaled);
|
|
Event(const Event&) = delete;
|
|
Event& operator=(const Event&) = delete;
|
|
~Event();
|
|
|
|
void Set();
|
|
void Reset();
|
|
|
|
// Waits for the event to become signaled, but logs a warning if it takes more
|
|
// than `warn_after`, and gives up completely if it takes more than
|
|
// `give_up_after`. (If `warn_after >= give_up_after`, no warning will be
|
|
// logged.) Either or both may be `kForever`, which means wait indefinitely.
|
|
//
|
|
// Care is taken so that the underlying OS wait call isn't requested to sleep
|
|
// shorter than `give_up_after`.
|
|
//
|
|
// Returns true if the event was signaled, false if there was a timeout or
|
|
// some other error.
|
|
bool Wait(webrtc::TimeDelta give_up_after, webrtc::TimeDelta warn_after);
|
|
|
|
// Waits with the given timeout and a reasonable default warning timeout.
|
|
bool Wait(webrtc::TimeDelta give_up_after) {
|
|
return Wait(give_up_after, give_up_after.IsPlusInfinity()
|
|
? webrtc::TimeDelta::Seconds(3)
|
|
: kForever);
|
|
}
|
|
|
|
private:
|
|
#if defined(WEBRTC_WIN)
|
|
HANDLE event_handle_;
|
|
#elif defined(WEBRTC_POSIX)
|
|
pthread_mutex_t event_mutex_;
|
|
pthread_cond_t event_cond_;
|
|
const bool is_manual_reset_;
|
|
bool event_status_;
|
|
#endif
|
|
};
|
|
|
|
// These classes are provided for compatibility with Chromium.
|
|
// The rtc::Event implementation is overriden inside of Chromium for the
|
|
// purposes of detecting when threads are blocked that shouldn't be as well as
|
|
// to use the more accurate event implementation that's there than is provided
|
|
// by default on some platforms (e.g. Windows).
|
|
// When building with standalone WebRTC, this class is a noop.
|
|
// For further information, please see the
|
|
// ScopedAllowBaseSyncPrimitives(ForTesting) classes in Chromium.
|
|
class ScopedAllowBaseSyncPrimitives {
|
|
public:
|
|
ScopedAllowBaseSyncPrimitives() {}
|
|
~ScopedAllowBaseSyncPrimitives() {}
|
|
};
|
|
|
|
class ScopedAllowBaseSyncPrimitivesForTesting {
|
|
public:
|
|
ScopedAllowBaseSyncPrimitivesForTesting() {}
|
|
~ScopedAllowBaseSyncPrimitivesForTesting() {}
|
|
};
|
|
|
|
#if RTC_DCHECK_IS_ON
|
|
class ScopedDisallowWait {
|
|
public:
|
|
ScopedDisallowWait() = default;
|
|
|
|
private:
|
|
class DisallowYieldHandler : public YieldInterface {
|
|
public:
|
|
void YieldExecution() override { RTC_DCHECK_NOTREACHED(); }
|
|
} handler_;
|
|
rtc::ScopedYieldPolicy policy{&handler_};
|
|
};
|
|
#endif
|
|
|
|
} // namespace rtc
|
|
|
|
#endif // RTC_BASE_EVENT_H_
|