1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_THREADING_THREAD_CHECKER_IMPL_H_ 6 #define BASE_THREADING_THREAD_CHECKER_IMPL_H_ 7 8 #include "base/base_export.h" 9 #include "base/compiler_specific.h" 10 #include "base/sequence_token.h" 11 #include "base/synchronization/lock.h" 12 #include "base/threading/platform_thread.h" 13 14 namespace base { 15 16 // Real implementation of ThreadChecker, for use in debug mode, or for temporary 17 // use in release mode (e.g. to CHECK on a threading issue seen only in the 18 // wild). 19 // 20 // Note: You should almost always use the ThreadChecker class to get the right 21 // version for your build configuration. 22 class BASE_EXPORT ThreadCheckerImpl { 23 public: 24 ThreadCheckerImpl(); 25 ~ThreadCheckerImpl(); 26 27 bool CalledOnValidThread() const WARN_UNUSED_RESULT; 28 29 // Changes the thread that is checked for in CalledOnValidThread. This may 30 // be useful when an object may be created on one thread and then used 31 // exclusively on another thread. 32 void DetachFromThread(); 33 34 private: 35 void EnsureAssigned() const; 36 37 // Members are mutable so that CalledOnValidThread() can set them. 38 39 // Synchronizes access to all members. 40 mutable base::Lock lock_; 41 42 // Thread on which CalledOnValidThread() may return true. 43 mutable PlatformThreadRef thread_id_; 44 45 // TaskToken for which CalledOnValidThread() always returns true. This allows 46 // CalledOnValidThread() to return true when called multiple times from the 47 // same task, even if it's not running in a single-threaded context itself 48 // (allowing usage of ThreadChecker/NonThreadSafe objects on the stack in the 49 // scope of one-off tasks). Note: CalledOnValidThread() may return true even 50 // if the current TaskToken is not equal to this. 51 mutable TaskToken task_token_; 52 53 // SequenceToken for which CalledOnValidThread() may return true. Used to 54 // ensure that CalledOnValidThread() doesn't return true for TaskScheduler 55 // tasks that happen to run on the same thread but weren't posted to the same 56 // SingleThreadTaskRunner. 57 mutable SequenceToken sequence_token_; 58 }; 59 60 } // namespace base 61 62 #endif // BASE_THREADING_THREAD_CHECKER_IMPL_H_ 63
