Move some misc thread-related stuff from base to base/thread and into the bas...

base/simple_thread.h

-// 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.
-
-// WARNING: You should probably be using Thread (thread.h) instead.  Thread is
-//          Chrome's message-loop based Thread abstraction, and if you are a
-//          thread running in the browser, there will likely be assumptions
-//          that your thread will have an associated message loop.
-//
-// This is a simple thread interface that backs to a native operating system
-// thread.  You should use this only when you want a thread that does not have
-// an associated MessageLoop.  Unittesting is the best example of this.
-//
-// The simplest interface to use is DelegateSimpleThread, which will create
-// a new thread, and execute the Delegate's virtual Run() in this new thread
-// until it has completed, exiting the thread.
-//
-// NOTE: You *MUST* call Join on the thread to clean up the underlying thread
-// resources.  You are also responsible for destructing the SimpleThread object.
-// It is invalid to destroy a SimpleThread while it is running, or without
-// Start() having been called (and a thread never created).  The Delegate
-// object should live as long as a DelegateSimpleThread.
-//
-// Thread Safety: A SimpleThread is not completely thread safe.  It is safe to
-// access it from the creating thread or from the newly created thread.  This
-// implies that the creator thread should be the thread that calls Join.
-//
-// Example:
-//   class MyThreadRunner : public DelegateSimpleThread::Delegate { ... };
-//   MyThreadRunner runner;
-//   DelegateSimpleThread thread(&runner, "good_name_here");
-//   thread.Start();
-//   // Start will return after the Thread has been successfully started and
-//   // initialized.  The newly created thread will invoke runner->Run(), and
-//   // run until it returns.
-//   thread.Join();  // Wait until the thread has exited.  You *MUST* Join!
-//   // The SimpleThread object is still valid, however you may not call Join
-//   // or Start again.
-
-#ifndef BASE_SIMPLE_THREAD_H_
-#define BASE_SIMPLE_THREAD_H_
-#pragma once
-
-#include <string>
-#include <queue>
-#include <vector>
-
-#include "base/basictypes.h"
-#include "base/lock.h"
-#include "base/waitable_event.h"
-#include "base/platform_thread.h"
-
-namespace base {
-
-// This is the base SimpleThread.  You can derive from it and implement the
-// virtual Run method, or you can use the DelegateSimpleThread interface.
-class SimpleThread : public PlatformThread::Delegate {
- public:
-  class Options {
-   public:
-    Options() : stack_size_(0) { }
-    ~Options() { }
-
-    // We use the standard compiler-supplied copy constructor.
-
-    // A custom stack size, or 0 for the system default.
-    void set_stack_size(size_t size) { stack_size_ = size; }
-    size_t stack_size() const { return stack_size_; }
-   private:
-    size_t stack_size_;
-  };
-
-  // Create a SimpleThread.  |options| should be used to manage any specific
-  // configuration involving the thread creation and management.
-  // Every thread has a name, in the form of |name_prefix|/TID, for example
-  // "my_thread/321".  The thread will not be created until Start() is called.
-  explicit SimpleThread(const std::string& name_prefix);
-  SimpleThread(const std::string& name_prefix, const Options& options);
-
-  virtual ~SimpleThread();
-
-  virtual void Start();
-  virtual void Join();
-
-  // We follow the PlatformThread Delegate interface.
-  virtual void ThreadMain();
-
-  // Subclasses should override the Run method.
-  virtual void Run() = 0;
-
-  // Return the thread name prefix, or "unnamed" if none was supplied.
-  std::string name_prefix() { return name_prefix_; }
-
-  // Return the completed name including TID, only valid after Start().
-  std::string name() { return name_; }
-
-  // Return the thread id, only valid after Start().
-  PlatformThreadId tid() { return tid_; }
-
-  // Return True if Start() has ever been called.
-  bool HasBeenStarted() { return event_.IsSignaled(); }
-
-  // Return True if Join() has evern been called.
-  bool HasBeenJoined() { return joined_; }
-
- private:
-  const std::string name_prefix_;
-  std::string name_;
-  const Options options_;
-  PlatformThreadHandle thread_;  // PlatformThread handle, invalid after Join!
-  WaitableEvent event_;          // Signaled if Start() was ever called.
-  PlatformThreadId tid_;         // The backing thread's id.
-  bool joined_;                  // True if Join has been called.
-};
-
-class DelegateSimpleThread : public SimpleThread {
- public:
-  class Delegate {
-   public:
-    Delegate() { }
-    virtual ~Delegate() { }
-    virtual void Run() = 0;
-  };
-
-  DelegateSimpleThread(Delegate* delegate,
-                       const std::string& name_prefix);
-  DelegateSimpleThread(Delegate* delegate,
-                       const std::string& name_prefix,
-                       const Options& options);
-
-  virtual ~DelegateSimpleThread();
-  virtual void Run();
- private:
-  Delegate* delegate_;
-};
-
-// DelegateSimpleThreadPool allows you to start up a fixed number of threads,
-// and then add jobs which will be dispatched to the threads.  This is
-// convenient when you have a lot of small work that you want done
-// multi-threaded, but don't want to spawn a thread for each small bit of work.
-//
-// You just call AddWork() to add a delegate to the list of work to be done.
-// JoinAll() will make sure that all outstanding work is processed, and wait
-// for everything to finish.  You can reuse a pool, so you can call Start()
-// again after you've called JoinAll().
-class DelegateSimpleThreadPool : public DelegateSimpleThread::Delegate {
- public:
-  typedef DelegateSimpleThread::Delegate Delegate;
-
-  DelegateSimpleThreadPool(const std::string& name_prefix, int num_threads);
-  virtual ~DelegateSimpleThreadPool();
-
-  // Start up all of the underlying threads, and start processing work if we
-  // have any.
-  void Start();
-
-  // Make sure all outstanding work is finished, and wait for and destroy all
-  // of the underlying threads in the pool.
-  void JoinAll();
-
-  // It is safe to AddWork() any time, before or after Start().
-  // Delegate* should always be a valid pointer, NULL is reserved internally.
-  void AddWork(Delegate* work, int repeat_count);
-  void AddWork(Delegate* work) {
-    AddWork(work, 1);
-  }
-
-  // We implement the Delegate interface, for running our internal threads.
-  virtual void Run();
-
- private:
-  const std::string name_prefix_;
-  int num_threads_;
-  std::vector<DelegateSimpleThread*> threads_;
-  std::queue<Delegate*> delegates_;
-  Lock lock_;            // Locks delegates_
-  WaitableEvent dry_;    // Not signaled when there is no work to do.
-};
-
-}  // namespace base
-
-#endif  // BASE_SIMPLE_THREAD_H_