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TMessagesProj/jni/voip/webrtc/rtc_base/event.h

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+/*
+ *  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_