Repo created

TMessagesProj/jni/voip/webrtc/rtc_base/deprecated/recursive_critical_section.cc

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+/*
+ *  Copyright 2015 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/deprecated/recursive_critical_section.h"
+
+#include <time.h>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/platform_thread_types.h"
+#include "rtc_base/synchronization/yield.h"
+#include "rtc_base/system/unused.h"
+
+#if RTC_DCHECK_IS_ON
+#define RTC_CS_DEBUG_CODE(x) x
+#else  // !RTC_DCHECK_IS_ON
+#define RTC_CS_DEBUG_CODE(x)
+#endif  // !RTC_DCHECK_IS_ON
+
+namespace rtc {
+
+RecursiveCriticalSection::RecursiveCriticalSection() {
+#if defined(WEBRTC_WIN)
+  InitializeCriticalSection(&crit_);
+#elif defined(WEBRTC_POSIX)
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+  lock_queue_ = 0;
+  owning_thread_ = 0;
+  recursion_ = 0;
+  semaphore_ = dispatch_semaphore_create(0);
+#else
+  pthread_mutexattr_t mutex_attribute;
+  pthread_mutexattr_init(&mutex_attribute);
+  pthread_mutexattr_settype(&mutex_attribute, PTHREAD_MUTEX_RECURSIVE);
+#if defined(WEBRTC_MAC)
+  pthread_mutexattr_setpolicy_np(&mutex_attribute,
+                                 _PTHREAD_MUTEX_POLICY_FIRSTFIT);
+#endif
+  pthread_mutex_init(&mutex_, &mutex_attribute);
+  pthread_mutexattr_destroy(&mutex_attribute);
+#endif
+  RTC_CS_DEBUG_CODE(thread_ = 0);
+  RTC_CS_DEBUG_CODE(recursion_count_ = 0);
+  RTC_UNUSED(thread_);
+  RTC_UNUSED(recursion_count_);
+#else
+#error Unsupported platform.
+#endif
+}
+
+RecursiveCriticalSection::~RecursiveCriticalSection() {
+#if defined(WEBRTC_WIN)
+  DeleteCriticalSection(&crit_);
+#elif defined(WEBRTC_POSIX)
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+  dispatch_release(semaphore_);
+#else
+  pthread_mutex_destroy(&mutex_);
+#endif
+#else
+#error Unsupported platform.
+#endif
+}
+
+void RecursiveCriticalSection::Enter() const RTC_EXCLUSIVE_LOCK_FUNCTION() {
+#if defined(WEBRTC_WIN)
+  EnterCriticalSection(&crit_);
+#elif defined(WEBRTC_POSIX)
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+  int spin = 3000;
+  PlatformThreadRef self = CurrentThreadRef();
+  bool have_lock = false;
+  do {
+    // Instead of calling TryEnter() in this loop, we do two interlocked
+    // operations, first a read-only one in order to avoid affecting the lock
+    // cache-line while spinning, in case another thread is using the lock.
+    if (!IsThreadRefEqual(owning_thread_, self)) {
+      if (AtomicOps::AcquireLoad(&lock_queue_) == 0) {
+        if (AtomicOps::CompareAndSwap(&lock_queue_, 0, 1) == 0) {
+          have_lock = true;
+          break;
+        }
+      }
+    } else {
+      AtomicOps::Increment(&lock_queue_);
+      have_lock = true;
+      break;
+    }
+
+    sched_yield();
+  } while (--spin);
+
+  if (!have_lock && AtomicOps::Increment(&lock_queue_) > 1) {
+    // Owning thread cannot be the current thread since TryEnter() would
+    // have succeeded.
+    RTC_DCHECK(!IsThreadRefEqual(owning_thread_, self));
+    // Wait for the lock to become available.
+    dispatch_semaphore_wait(semaphore_, DISPATCH_TIME_FOREVER);
+    RTC_DCHECK(owning_thread_ == 0);
+    RTC_DCHECK(!recursion_);
+  }
+
+  owning_thread_ = self;
+  ++recursion_;
+
+#else
+  pthread_mutex_lock(&mutex_);
+#endif
+
+#if RTC_DCHECK_IS_ON
+  if (!recursion_count_) {
+    RTC_DCHECK(!thread_);
+    thread_ = CurrentThreadRef();
+  } else {
+    RTC_DCHECK(CurrentThreadIsOwner());
+  }
+  ++recursion_count_;
+#endif
+#else
+#error Unsupported platform.
+#endif
+}
+
+bool RecursiveCriticalSection::TryEnter() const
+    RTC_EXCLUSIVE_TRYLOCK_FUNCTION(true) {
+#if defined(WEBRTC_WIN)
+  return TryEnterCriticalSection(&crit_) != FALSE;
+#elif defined(WEBRTC_POSIX)
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+  if (!IsThreadRefEqual(owning_thread_, CurrentThreadRef())) {
+    if (AtomicOps::CompareAndSwap(&lock_queue_, 0, 1) != 0)
+      return false;
+    owning_thread_ = CurrentThreadRef();
+    RTC_DCHECK(!recursion_);
+  } else {
+    AtomicOps::Increment(&lock_queue_);
+  }
+  ++recursion_;
+#else
+  if (pthread_mutex_trylock(&mutex_) != 0)
+    return false;
+#endif
+#if RTC_DCHECK_IS_ON
+  if (!recursion_count_) {
+    RTC_DCHECK(!thread_);
+    thread_ = CurrentThreadRef();
+  } else {
+    RTC_DCHECK(CurrentThreadIsOwner());
+  }
+  ++recursion_count_;
+#endif
+  return true;
+#else
+#error Unsupported platform.
+#endif
+}
+
+void RecursiveCriticalSection::Leave() const RTC_UNLOCK_FUNCTION() {
+  RTC_DCHECK(CurrentThreadIsOwner());
+#if defined(WEBRTC_WIN)
+  LeaveCriticalSection(&crit_);
+#elif defined(WEBRTC_POSIX)
+#if RTC_DCHECK_IS_ON
+  --recursion_count_;
+  RTC_DCHECK(recursion_count_ >= 0);
+  if (!recursion_count_)
+    thread_ = 0;
+#endif
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+  RTC_DCHECK(IsThreadRefEqual(owning_thread_, CurrentThreadRef()));
+  RTC_DCHECK_GE(recursion_, 0);
+  --recursion_;
+  if (!recursion_)
+    owning_thread_ = 0;
+
+  if (AtomicOps::Decrement(&lock_queue_) > 0 && !recursion_)
+    dispatch_semaphore_signal(semaphore_);
+#else
+  pthread_mutex_unlock(&mutex_);
+#endif
+#else
+#error Unsupported platform.
+#endif
+}
+
+bool RecursiveCriticalSection::CurrentThreadIsOwner() const {
+#if defined(WEBRTC_WIN)
+  // OwningThread has type HANDLE but actually contains the Thread ID:
+  // http://stackoverflow.com/questions/12675301/why-is-the-owningthread-member-of-critical-section-of-type-handle-when-it-is-de
+  // Converting through size_t avoids the VS 2015 warning C4312: conversion from
+  // 'type1' to 'type2' of greater size
+  return crit_.OwningThread ==
+         reinterpret_cast<HANDLE>(static_cast<size_t>(GetCurrentThreadId()));
+#elif defined(WEBRTC_POSIX)
+#if RTC_DCHECK_IS_ON
+  return IsThreadRefEqual(thread_, CurrentThreadRef());
+#else
+  return true;
+#endif  // RTC_DCHECK_IS_ON
+#else
+#error Unsupported platform.
+#endif
+}
+
+CritScope::CritScope(const RecursiveCriticalSection* cs) : cs_(cs) {
+  cs_->Enter();
+}
+CritScope::~CritScope() {
+  cs_->Leave();
+}
+
+}  // namespace rtc

TMessagesProj/jni/voip/webrtc/rtc_base/deprecated/recursive_critical_section.h

@@ -0,0 +1,107 @@
+/*
+ *  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_DEPRECATED_RECURSIVE_CRITICAL_SECTION_H_
+#define RTC_BASE_DEPRECATED_RECURSIVE_CRITICAL_SECTION_H_
+
+#include <atomic>
+
+#include "rtc_base/platform_thread_types.h"
+#include "rtc_base/thread_annotations.h"
+
+#if defined(WEBRTC_WIN)
+// clang-format off
+// clang formating would change include order.
+
+// Include winsock2.h before including <windows.h> to maintain consistency with
+// win32.h. To include win32.h directly, it must be broken out into its own
+// build target.
+#include <winsock2.h>
+#include <windows.h>
+#include <sal.h>  // must come after windows headers.
+// clang-format on
+#endif  // defined(WEBRTC_WIN)
+
+#if defined(WEBRTC_POSIX)
+#include <pthread.h>
+#endif
+
+// See notes in the 'Performance' unit test for the effects of this flag.
+#define RTC_USE_NATIVE_MUTEX_ON_MAC 1
+
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+#include <dispatch/dispatch.h>
+#endif
+
+namespace rtc {
+
+// NOTE: This class is deprecated. Please use webrtc::Mutex instead!
+// Search using https://www.google.com/?q=recursive+lock+considered+harmful
+// to find the reasons.
+//
+// Locking methods (Enter, TryEnter, Leave)are const to permit protecting
+// members inside a const context without requiring mutable
+// RecursiveCriticalSections everywhere. RecursiveCriticalSection is
+// reentrant lock.
+class RTC_LOCKABLE RecursiveCriticalSection {
+ public:
+  RecursiveCriticalSection();
+  ~RecursiveCriticalSection();
+
+  void Enter() const RTC_EXCLUSIVE_LOCK_FUNCTION();
+  bool TryEnter() const RTC_EXCLUSIVE_TRYLOCK_FUNCTION(true);
+  void Leave() const RTC_UNLOCK_FUNCTION();
+
+ private:
+  // Use only for RTC_DCHECKing.
+  bool CurrentThreadIsOwner() const;
+
+#if defined(WEBRTC_WIN)
+  mutable CRITICAL_SECTION crit_;
+#elif defined(WEBRTC_POSIX)
+#if defined(WEBRTC_MAC) && !RTC_USE_NATIVE_MUTEX_ON_MAC
+  // Number of times the lock has been locked + number of threads waiting.
+  // TODO(tommi): We could use this number and subtract the recursion count
+  // to find places where we have multiple threads contending on the same lock.
+  mutable std::atomic<int> lock_queue_;
+  // `recursion_` represents the recursion count + 1 for the thread that owns
+  // the lock. Only modified by the thread that owns the lock.
+  mutable int recursion_;
+  // Used to signal a single waiting thread when the lock becomes available.
+  mutable dispatch_semaphore_t semaphore_;
+  // The thread that currently holds the lock. Required to handle recursion.
+  mutable PlatformThreadRef owning_thread_;
+#else
+  mutable pthread_mutex_t mutex_;
+#endif
+  mutable PlatformThreadRef thread_;  // Only used by RTC_DCHECKs.
+  mutable int recursion_count_;       // Only used by RTC_DCHECKs.
+#else  // !defined(WEBRTC_WIN) && !defined(WEBRTC_POSIX)
+#error Unsupported platform.
+#endif
+};
+
+// CritScope, for serializing execution through a scope.
+class RTC_SCOPED_LOCKABLE CritScope {
+ public:
+  explicit CritScope(const RecursiveCriticalSection* cs)
+      RTC_EXCLUSIVE_LOCK_FUNCTION(cs);
+  ~CritScope() RTC_UNLOCK_FUNCTION();
+
+  CritScope(const CritScope&) = delete;
+  CritScope& operator=(const CritScope&) = delete;
+
+ private:
+  const RecursiveCriticalSection* const cs_;
+};
+
+}  // namespace rtc
+
+#endif  // RTC_BASE_DEPRECATED_RECURSIVE_CRITICAL_SECTION_H_