1 files changed, 203 insertions, 0 deletions
diff --git a/webrtc/rtc_base/event.cc b/webrtc/rtc_base/event.cc
new file mode 100644
index 0000000..67c8746
--- /dev/null
+++ b/webrtc/rtc_base/event.cc
@@ -0,0 +1,203 @@
+/*
+ *  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.
+ */
+
+#include "rtc_base/event.h"
+
+#if defined(WEBRTC_WIN)
+#include <windows.h>
+#elif defined(WEBRTC_POSIX)
+#include <errno.h>
+#include <pthread.h>
+#include <sys/time.h>
+#include <time.h>
+#else
+#error "Must define either WEBRTC_WIN or WEBRTC_POSIX."
+#endif
+
+#include "absl/types/optional.h"
+#include "rtc_base/checks.h"
+#include "rtc_base/synchronization/yield_policy.h"
+#include "rtc_base/system/warn_current_thread_is_deadlocked.h"
+
+namespace rtc {
+
+Event::Event() : Event(false, false) {}
+
+#if defined(WEBRTC_WIN)
+
+Event::Event(bool manual_reset, bool initially_signaled) {
+  event_handle_ = ::CreateEvent(nullptr,  // Security attributes.
+                                manual_reset, initially_signaled,
+                                nullptr);  // Name.
+  RTC_CHECK(event_handle_);
+}
+
+Event::~Event() {
+  CloseHandle(event_handle_);
+}
+
+void Event::Set() {
+  SetEvent(event_handle_);
+}
+
+void Event::Reset() {
+  ResetEvent(event_handle_);
+}
+
+bool Event::Wait(const int give_up_after_ms, int /*warn_after_ms*/) {
+  ScopedYieldPolicy::YieldExecution();
+  const DWORD ms = give_up_after_ms == kForever ? INFINITE : give_up_after_ms;
+  return (WaitForSingleObject(event_handle_, ms) == WAIT_OBJECT_0);
+}
+
+#elif defined(WEBRTC_POSIX)
+
+// On MacOS, clock_gettime is available from version 10.12, and on
+// iOS, from version 10.0. So we can't use it yet.
+#if defined(WEBRTC_MAC) || defined(WEBRTC_IOS)
+#define USE_CLOCK_GETTIME 0
+#define USE_PTHREAD_COND_TIMEDWAIT_MONOTONIC_NP 0
+// On Android, pthread_condattr_setclock is available from version 21. By
+// default, we target a new enough version for 64-bit platforms but not for
+// 32-bit platforms. For older versions, use
+// pthread_cond_timedwait_monotonic_np.
+#elif defined(WEBRTC_ANDROID) && (__ANDROID_API__ < 21)
+#define USE_CLOCK_GETTIME 1
+#define USE_PTHREAD_COND_TIMEDWAIT_MONOTONIC_NP 1
+#else
+#define USE_CLOCK_GETTIME 1
+#define USE_PTHREAD_COND_TIMEDWAIT_MONOTONIC_NP 0
+#endif
+
+Event::Event(bool manual_reset, bool initially_signaled)
+    : is_manual_reset_(manual_reset), event_status_(initially_signaled) {
+  RTC_CHECK(pthread_mutex_init(&event_mutex_, nullptr) == 0);
+  pthread_condattr_t cond_attr;
+  RTC_CHECK(pthread_condattr_init(&cond_attr) == 0);
+#if USE_CLOCK_GETTIME && !USE_PTHREAD_COND_TIMEDWAIT_MONOTONIC_NP
+  RTC_CHECK(pthread_condattr_setclock(&cond_attr, CLOCK_MONOTONIC) == 0);
+#endif
+  RTC_CHECK(pthread_cond_init(&event_cond_, &cond_attr) == 0);
+  pthread_condattr_destroy(&cond_attr);
+}
+
+Event::~Event() {
+  pthread_mutex_destroy(&event_mutex_);
+  pthread_cond_destroy(&event_cond_);
+}
+
+void Event::Set() {
+  pthread_mutex_lock(&event_mutex_);
+  event_status_ = true;
+  pthread_cond_broadcast(&event_cond_);
+  pthread_mutex_unlock(&event_mutex_);
+}
+
+void Event::Reset() {
+  pthread_mutex_lock(&event_mutex_);
+  event_status_ = false;
+  pthread_mutex_unlock(&event_mutex_);
+}
+
+namespace {
+
+timespec GetTimespec(const int milliseconds_from_now) {
+  timespec ts;
+
+  // Get the current time.
+#if USE_CLOCK_GETTIME
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+#else
+  timeval tv;
+  gettimeofday(&tv, nullptr);
+  ts.tv_sec = tv.tv_sec;
+  ts.tv_nsec = tv.tv_usec * 1000;
+#endif
+
+  // Add the specified number of milliseconds to it.
+  ts.tv_sec += (milliseconds_from_now / 1000);
+  ts.tv_nsec += (milliseconds_from_now % 1000) * 1000000;
+
+  // Normalize.
+  if (ts.tv_nsec >= 1000000000) {
+    ts.tv_sec++;
+    ts.tv_nsec -= 1000000000;
+  }
+
+  return ts;
+}
+
+}  // namespace
+
+bool Event::Wait(const int give_up_after_ms, const int warn_after_ms) {
+  // Instant when we'll log a warning message (because we've been waiting so
+  // long it might be a bug), but not yet give up waiting. nullopt if we
+  // shouldn't log a warning.
+  const absl::optional<timespec> warn_ts =
+      warn_after_ms == kForever ||
+              (give_up_after_ms != kForever && warn_after_ms > give_up_after_ms)
+          ? absl::nullopt
+          : absl::make_optional(GetTimespec(warn_after_ms));
+
+  // Instant when we'll stop waiting and return an error. nullopt if we should
+  // never give up.
+  const absl::optional<timespec> give_up_ts =
+      give_up_after_ms == kForever
+          ? absl::nullopt
+          : absl::make_optional(GetTimespec(give_up_after_ms));
+
+  ScopedYieldPolicy::YieldExecution();
+  pthread_mutex_lock(&event_mutex_);
+
+  // Wait for `event_cond_` to trigger and `event_status_` to be set, with the
+  // given timeout (or without a timeout if none is given).
+  const auto wait = [&](const absl::optional<timespec> timeout_ts) {
+    int error = 0;
+    while (!event_status_ && error == 0) {
+      if (timeout_ts == absl::nullopt) {
+        error = pthread_cond_wait(&event_cond_, &event_mutex_);
+      } else {
+#if USE_PTHREAD_COND_TIMEDWAIT_MONOTONIC_NP
+        error = pthread_cond_timedwait_monotonic_np(&event_cond_, &event_mutex_,
+                                                    &*timeout_ts);
+#else
+        error =
+            pthread_cond_timedwait(&event_cond_, &event_mutex_, &*timeout_ts);
+#endif
+      }
+    }
+    return error;
+  };
+
+  int error;
+  if (warn_ts == absl::nullopt) {
+    error = wait(give_up_ts);
+  } else {
+    error = wait(warn_ts);
+    if (error == ETIMEDOUT) {
+      webrtc::WarnThatTheCurrentThreadIsProbablyDeadlocked();
+      error = wait(give_up_ts);
+    }
+  }
+
+  // NOTE(liulk): Exactly one thread will auto-reset this event. All
+  // the other threads will think it's unsignaled.  This seems to be
+  // consistent with auto-reset events in WEBRTC_WIN
+  if (error == 0 && !is_manual_reset_)
+    event_status_ = false;
+
+  pthread_mutex_unlock(&event_mutex_);
+
+  return (error == 0);
+}
+
+#endif
+
+}  // namespace rtc