| /* |
| * 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 "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 volatile 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_ |