Delete SignalThread class.

webrtc/rtc_base/signalthread.h

-/*
- *  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_RTC_BASE_SIGNALTHREAD_H_
-#define WEBRTC_RTC_BASE_SIGNALTHREAD_H_
-
-#include <string>
-
-#include "webrtc/base/checks.h"
-#include "webrtc/base/constructormagic.h"
-#include "webrtc/base/nullsocketserver.h"
-#include "webrtc/base/sigslot.h"
-#include "webrtc/base/thread.h"
-
-namespace rtc {
-
-///////////////////////////////////////////////////////////////////////////////
-// SignalThread - Base class for worker threads.  The main thread should call
-//  Start() to begin work, and then follow one of these models:
-//   Normal: Wait for SignalWorkDone, and then call Release to destroy.
-//   Cancellation: Call Release(true), to abort the worker thread.
-//   Fire-and-forget: Call Release(false), which allows the thread to run to
-//    completion, and then self-destruct without further notification.
-//   Periodic tasks: Wait for SignalWorkDone, then eventually call Start()
-//    again to repeat the task. When the instance isn't needed anymore,
-//    call Release. DoWork, OnWorkStart and OnWorkStop are called again,
-//    on a new thread.
-//  The subclass should override DoWork() to perform the background task.  By
-//   periodically calling ContinueWork(), it can check for cancellation.
-//   OnWorkStart and OnWorkDone can be overridden to do pre- or post-work
-//   tasks in the context of the main thread.
-///////////////////////////////////////////////////////////////////////////////
-
-class SignalThread
-    : public sigslot::has_slots<>,
-      protected MessageHandler {
- public:
-  explicit SignalThread(bool use_socket_server = true);
-
-  // Context: Main Thread.  Call before Start to change the worker's name.
-  bool SetName(const std::string& name, const void* obj);
-
-  // Context: Main Thread.  Call to begin the worker thread.
-  void Start();
-
-  // Context: Main Thread.  If the worker thread is not running, deletes the
-  // object immediately.  Otherwise, asks the worker thread to abort processing,
-  // and schedules the object to be deleted once the worker exits.
-  // SignalWorkDone will not be signalled.  If wait is true, does not return
-  // until the thread is deleted.
-  void Destroy(bool wait);
-
-  // Context: Main Thread.  If the worker thread is complete, deletes the
-  // object immediately.  Otherwise, schedules the object to be deleted once
-  // the worker thread completes.  SignalWorkDone will be signalled.
-  void Release();
-
-  // Context: Main Thread.  Signalled when work is complete.
-  sigslot::signal1<SignalThread *> SignalWorkDone;
-
-  enum { ST_MSG_WORKER_DONE, ST_MSG_FIRST_AVAILABLE };
-
- protected:
-  ~SignalThread() override;
-
-  Thread* worker() { return &worker_; }
-
-  // Context: Main Thread.  Subclass should override to do pre-work setup.
-  virtual void OnWorkStart() { }
-
-  // Context: Worker Thread.  Subclass should override to do work.
-  virtual void DoWork() = 0;
-
-  // Context: Worker Thread.  Subclass should call periodically to
-  // dispatch messages and determine if the thread should terminate.
-  bool ContinueWork();
-
-  // Context: Worker Thread.  Subclass should override when extra work is
-  // needed to abort the worker thread.
-  virtual void OnWorkStop() { }
-
-  // Context: Main Thread.  Subclass should override to do post-work cleanup.
-  virtual void OnWorkDone() { }
-
-  // Context: Any Thread.  If subclass overrides, be sure to call the base
-  // implementation.  Do not use (message_id < ST_MSG_FIRST_AVAILABLE)
-  void OnMessage(Message* msg) override;
-
- private:
-  enum State {
-    kInit,            // Initialized, but not started
-    kRunning,         // Started and doing work
-    kReleasing,       // Same as running, but to be deleted when work is done
-    kComplete,        // Work is done
-    kStopping,        // Work is being interrupted
-  };
-
-  class Worker : public Thread {
-   public:
-    explicit Worker(SignalThread* parent, bool use_socket_server)
-        : Thread(use_socket_server
-                     ? SocketServer::CreateDefault()
-                     : std::unique_ptr<SocketServer>(new NullSocketServer())),
-          parent_(parent) {}
-    ~Worker() override;
-    void Run() override;
-    bool IsProcessingMessages() override;
-
-   private:
-    SignalThread* parent_;
-
-    RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(Worker);
-  };
-
-  class SCOPED_LOCKABLE EnterExit {
-   public:
-    explicit EnterExit(SignalThread* t) EXCLUSIVE_LOCK_FUNCTION(t->cs_)
-        : t_(t) {
-      t_->cs_.Enter();
-      // If refcount_ is zero then the object has already been deleted and we
-      // will be double-deleting it in ~EnterExit()! (shouldn't happen)
-      RTC_DCHECK_NE(0, t_->refcount_);
-      ++t_->refcount_;
-    }
-    ~EnterExit() UNLOCK_FUNCTION() {
-      bool d = (0 == --t_->refcount_);
-      t_->cs_.Leave();
-      if (d)
-        delete t_;
-    }
-
-   private:
-    SignalThread* t_;
-
-    RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(EnterExit);
-  };
-
-  void Run();
-  void OnMainThreadDestroyed();
-
-  Thread* main_;
-  Worker worker_;
-  CriticalSection cs_;
-  State state_;
-  int refcount_;
-
-  RTC_DISALLOW_COPY_AND_ASSIGN(SignalThread);
-};
-
-///////////////////////////////////////////////////////////////////////////////
-
-}  // namespace rtc
-
-#endif  // WEBRTC_RTC_BASE_SIGNALTHREAD_H_