Adds a modified copy of talk/base to webrtc/base. It is the first step in migrating talk/base to webrtc/base.

BUG=N/A
R=andrew@webrtc.org, wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/12199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6107 4adac7df-926f-26a2-2b94-8c16560cd09d

webrtc/base/thread.h

@@ -0,0 +1,285 @@
+/*
+ *  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 WEBRTC_BASE_THREAD_H_
+#define WEBRTC_BASE_THREAD_H_
+
+#include <algorithm>
+#include <list>
+#include <string>
+#include <vector>
+
+#if defined(WEBRTC_POSIX)
+#include <pthread.h>
+#endif
+#include "webrtc/base/constructormagic.h"
+#include "webrtc/base/messagequeue.h"
+
+#if defined(WEBRTC_WIN)
+#include "webrtc/base/win32.h"
+#endif
+
+namespace rtc {
+
+class Thread;
+
+class ThreadManager {
+ public:
+  ThreadManager();
+  ~ThreadManager();
+
+  static ThreadManager* Instance();
+
+  Thread* CurrentThread();
+  void SetCurrentThread(Thread* thread);
+
+  // Returns a thread object with its thread_ ivar set
+  // to whatever the OS uses to represent the thread.
+  // If there already *is* a Thread object corresponding to this thread,
+  // this method will return that.  Otherwise it creates a new Thread
+  // object whose wrapped() method will return true, and whose
+  // handle will, on Win32, be opened with only synchronization privileges -
+  // if you need more privilegs, rather than changing this method, please
+  // write additional code to adjust the privileges, or call a different
+  // factory method of your own devising, because this one gets used in
+  // unexpected contexts (like inside browser plugins) and it would be a
+  // shame to break it.  It is also conceivable on Win32 that we won't even
+  // be able to get synchronization privileges, in which case the result
+  // will have a NULL handle.
+  Thread *WrapCurrentThread();
+  void UnwrapCurrentThread();
+
+ private:
+#if defined(WEBRTC_POSIX)
+  pthread_key_t key_;
+#endif
+
+#if defined(WEBRTC_WIN)
+  DWORD key_;
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(ThreadManager);
+};
+
+struct _SendMessage {
+  _SendMessage() {}
+  Thread *thread;
+  Message msg;
+  bool *ready;
+};
+
+enum ThreadPriority {
+  PRIORITY_IDLE = -1,
+  PRIORITY_NORMAL = 0,
+  PRIORITY_ABOVE_NORMAL = 1,
+  PRIORITY_HIGH = 2,
+};
+
+class Runnable {
+ public:
+  virtual ~Runnable() {}
+  virtual void Run(Thread* thread) = 0;
+
+ protected:
+  Runnable() {}
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Runnable);
+};
+
+// WARNING! SUBCLASSES MUST CALL Stop() IN THEIR DESTRUCTORS!  See ~Thread().
+
+class Thread : public MessageQueue {
+ public:
+  explicit Thread(SocketServer* ss = NULL);
+  // NOTE: ALL SUBCLASSES OF Thread MUST CALL Stop() IN THEIR DESTRUCTORS (or
+  // guarantee Stop() is explicitly called before the subclass is destroyed).
+  // This is required to avoid a data race between the destructor modifying the
+  // vtable, and the Thread::PreRun calling the virtual method Run().
+  virtual ~Thread();
+
+  static Thread* Current();
+
+  bool IsCurrent() const {
+    return Current() == this;
+  }
+
+  // Sleeps the calling thread for the specified number of milliseconds, during
+  // which time no processing is performed. Returns false if sleeping was
+  // interrupted by a signal (POSIX only).
+  static bool SleepMs(int millis);
+
+  // Sets the thread's name, for debugging. Must be called before Start().
+  // If |obj| is non-NULL, its value is appended to |name|.
+  const std::string& name() const { return name_; }
+  bool SetName(const std::string& name, const void* obj);
+
+  // Sets the thread's priority. Must be called before Start().
+  ThreadPriority priority() const { return priority_; }
+  bool SetPriority(ThreadPriority priority);
+
+  // Starts the execution of the thread.
+  bool started() const { return started_; }
+  bool Start(Runnable* runnable = NULL);
+
+  // Used for fire-and-forget threads.  Deletes this thread object when the
+  // Run method returns.
+  void Release() {
+    delete_self_when_complete_ = true;
+  }
+
+  // Tells the thread to stop and waits until it is joined.
+  // Never call Stop on the current thread.  Instead use the inherited Quit
+  // function which will exit the base MessageQueue without terminating the
+  // underlying OS thread.
+  virtual void Stop();
+
+  // By default, Thread::Run() calls ProcessMessages(kForever).  To do other
+  // work, override Run().  To receive and dispatch messages, call
+  // ProcessMessages occasionally.
+  virtual void Run();
+
+  virtual void Send(MessageHandler *phandler, uint32 id = 0,
+      MessageData *pdata = NULL);
+
+  // Convenience method to invoke a functor on another thread.  Caller must
+  // provide the |ReturnT| template argument, which cannot (easily) be deduced.
+  // Uses Send() internally, which blocks the current thread until execution
+  // is complete.
+  // Ex: bool result = thread.Invoke<bool>(&MyFunctionReturningBool);
+  template <class ReturnT, class FunctorT>
+  ReturnT Invoke(const FunctorT& functor) {
+    FunctorMessageHandler<ReturnT, FunctorT> handler(functor);
+    Send(&handler);
+    return handler.result();
+  }
+
+  // From MessageQueue
+  virtual void Clear(MessageHandler *phandler, uint32 id = MQID_ANY,
+                     MessageList* removed = NULL);
+  virtual void ReceiveSends();
+
+  // ProcessMessages will process I/O and dispatch messages until:
+  //  1) cms milliseconds have elapsed (returns true)
+  //  2) Stop() is called (returns false)
+  bool ProcessMessages(int cms);
+
+  // Returns true if this is a thread that we created using the standard
+  // constructor, false if it was created by a call to
+  // ThreadManager::WrapCurrentThread().  The main thread of an application
+  // is generally not owned, since the OS representation of the thread
+  // obviously exists before we can get to it.
+  // You cannot call Start on non-owned threads.
+  bool IsOwned();
+
+#if defined(WEBRTC_WIN)
+  HANDLE GetHandle() const {
+    return thread_;
+  }
+  DWORD GetId() const {
+    return thread_id_;
+  }
+#elif defined(WEBRTC_POSIX)
+  pthread_t GetPThread() {
+    return thread_;
+  }
+#endif
+
+  // This method should be called when thread is created using non standard
+  // method, like derived implementation of rtc::Thread and it can not be
+  // started by calling Start(). This will set started flag to true and
+  // owned to false. This must be called from the current thread.
+  // NOTE: These methods should be used by the derived classes only, added here
+  // only for testing.
+  bool WrapCurrent();
+  void UnwrapCurrent();
+
+ protected:
+  // Blocks the calling thread until this thread has terminated.
+  void Join();
+
+ private:
+  static void *PreRun(void *pv);
+
+  // ThreadManager calls this instead WrapCurrent() because
+  // ThreadManager::Instance() cannot be used while ThreadManager is
+  // being created.
+  bool WrapCurrentWithThreadManager(ThreadManager* thread_manager);
+
+  std::list<_SendMessage> sendlist_;
+  std::string name_;
+  ThreadPriority priority_;
+  bool started_;
+
+#if defined(WEBRTC_POSIX)
+  pthread_t thread_;
+#endif
+
+#if defined(WEBRTC_WIN)
+  HANDLE thread_;
+  DWORD thread_id_;
+#endif
+
+  bool owned_;
+  bool delete_self_when_complete_;
+
+  friend class ThreadManager;
+
+  DISALLOW_COPY_AND_ASSIGN(Thread);
+};
+
+// AutoThread automatically installs itself at construction
+// uninstalls at destruction, if a Thread object is
+// _not already_ associated with the current OS thread.
+
+class AutoThread : public Thread {
+ public:
+  explicit AutoThread(SocketServer* ss = 0);
+  virtual ~AutoThread();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(AutoThread);
+};
+
+// Win32 extension for threads that need to use COM
+#if defined(WEBRTC_WIN)
+class ComThread : public Thread {
+ public:
+  ComThread() {}
+  virtual ~ComThread() { Stop(); }
+
+ protected:
+  virtual void Run();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ComThread);
+};
+#endif
+
+// Provides an easy way to install/uninstall a socketserver on a thread.
+class SocketServerScope {
+ public:
+  explicit SocketServerScope(SocketServer* ss) {
+    old_ss_ = Thread::Current()->socketserver();
+    Thread::Current()->set_socketserver(ss);
+  }
+  ~SocketServerScope() {
+    Thread::Current()->set_socketserver(old_ss_);
+  }
+
+ private:
+  SocketServer* old_ss_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(SocketServerScope);
+};
+
+}  // namespace rtc
+
+#endif  // WEBRTC_BASE_THREAD_H_