| // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef BASE_THREAD_H_ |
| #define BASE_THREAD_H_ |
| |
| #include <string> |
| |
| #include "base/platform_thread.h" |
| #include "base/thread_local_storage.h" |
| |
| class MessageLoop; |
| |
| namespace base { |
| class WaitableEvent; |
| } |
| |
| // A simple thread abstraction that establishes a MessageLoop on a new thread. |
| // The consumer uses the MessageLoop of the thread to cause code to execute on |
| // the thread. When this object is destroyed the thread is terminated. All |
| // pending tasks queued on the thread's message loop will run to completion |
| // before the thread is terminated. |
| class Thread : PlatformThread::Delegate { |
| public: |
| // Constructor. |
| // name is a display string to identify the thread. |
| explicit Thread(const char *name); |
| |
| // Destroys the thread, stopping it if necessary. |
| // |
| virtual ~Thread(); |
| |
| // Starts the thread. Returns true if the thread was successfully started; |
| // otherwise, returns false. Upon successful return, the message_loop() |
| // getter will return non-null. |
| // |
| // Note: This function can't be called on Windows with the loader lock held; |
| // i.e. during a DllMain, global object construction or destruction, atexit() |
| // callback. |
| bool Start(); |
| |
| // Starts the thread. Behaves exactly like Start in addition to allow to |
| // override the default process stack size. This is not the initial stack size |
| // but the maximum stack size that thread is allowed to use. |
| // |
| // Note: This function can't be called on Windows with the loader lock held; |
| // i.e. during a DllMain, global object construction or destruction, atexit() |
| // callback. |
| bool StartWithStackSize(size_t stack_size); |
| |
| // Signals the thread to exit and returns once the thread has exited. After |
| // this method returns, the Thread object is completely reset and may be used |
| // as if it were newly constructed (i.e., Start may be called again). |
| // |
| // Stop may be called multiple times and is simply ignored if the thread is |
| // already stopped. |
| // |
| // NOTE: This method is optional. It is not strictly necessary to call this |
| // method as the Thread's destructor will take care of stopping the thread if |
| // necessary. |
| // |
| void Stop(); |
| |
| // Signals the thread to exit in the near future. |
| // |
| // WARNING: This function is not meant to be commonly used. Use at your own |
| // risk. Calling this function will cause message_loop() to become invalid in |
| // the near future. This function was created to workaround a specific |
| // deadlock on Windows with printer worker thread. In any other case, Stop() |
| // should be used. |
| // |
| // StopSoon should not be called multiple times as it is risky to do so. It |
| // could cause a timing issue in message_loop() access. Call Stop() to reset |
| // the thread object once it is known that the thread has quit. |
| void StopSoon(); |
| |
| // Returns the message loop for this thread. Use the MessageLoop's |
| // PostTask methods to execute code on the thread. This only returns |
| // non-null after a successful call to Start. After Stop has been called, |
| // this will return NULL. |
| // |
| // NOTE: You must not call this MessageLoop's Quit method directly. Use |
| // the Thread's Stop method instead. |
| // |
| MessageLoop* message_loop() const { return message_loop_; } |
| |
| // Set the name of this thread (for display in debugger too). |
| const std::string &thread_name() { return name_; } |
| |
| // The native thread handle. |
| PlatformThreadHandle thread_handle() { return thread_; } |
| |
| protected: |
| // Called just prior to starting the message loop |
| virtual void Init() { } |
| |
| // Called just after the message loop ends |
| virtual void CleanUp() { } |
| |
| static void SetThreadWasQuitProperly(bool flag); |
| static bool GetThreadWasQuitProperly(); |
| |
| private: |
| // PlatformThread::Delegate methods: |
| virtual void ThreadMain(); |
| |
| // The thread's handle. |
| PlatformThreadHandle thread_; |
| |
| // The thread's ID. Used for debugging purposes. |
| int thread_id_; |
| |
| // The thread's message loop. Valid only while the thread is alive. Set |
| // by the created thread. |
| MessageLoop* message_loop_; |
| |
| // Used to synchronize thread startup. |
| base::WaitableEvent* startup_event_; |
| |
| // The name of the thread. Used for debugging purposes. |
| std::string name_; |
| |
| // This flag indicates if we created a thread that needs to be joined. |
| bool thread_created_; |
| |
| static TLSSlot tls_index_; |
| |
| friend class ThreadQuitTask; |
| |
| DISALLOW_COPY_AND_ASSIGN(Thread); |
| }; |
| |
| #endif // BASE_THREAD_H_ |
| |