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// 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 CHROME_COMMON_CHILD_PROCESS_H__
#define CHROME_COMMON_CHILD_PROCESS_H__
#include <string>
#include <vector>
#include "base/atomic_ref_count.h"
#include "base/basictypes.h"
#include "base/message_loop.h"
#include "base/scoped_ptr.h"
#include "base/waitable_event.h"
class ChildThread;
// Base class for child processes of the browser process (i.e. renderer and
// plugin host). This is a singleton object for each child process.
class ChildProcess {
public:
// Child processes should have an object that derives from this class. The
// constructor will return once ChildThread has started.
ChildProcess(ChildThread* child_thread);
virtual ~ChildProcess();
// Getter for this process' main thread.
ChildThread* child_thread() { return child_thread_.get(); }
// A global event object that is signalled when the main thread's message
// loop exits. This gives background threads a way to observe the main
// thread shutting down. This can be useful when a background thread is
// waiting for some information from the browser process. If the browser
// process goes away prematurely, the background thread can at least notice
// the child processes's main thread exiting to determine that it should give
// up waiting.
// For example, see the renderer code used to implement
// webkit_glue::GetCookies.
base::WaitableEvent* GetShutDownEvent();
// These are used for ref-counting the child process. The process shuts
// itself down when the ref count reaches 0. These functions may be called
// on any thread.
// For example, in the renderer process, generally each tab managed by this
// process will hold a reference to the process, and release when closed.
void AddRefProcess();
void ReleaseProcess();
protected:
friend class ChildThread;
// Getter for the one ChildProcess object for this process.
static ChildProcess* current() { return child_process_; }
protected:
bool ProcessRefCountIsZero();
// Derived classes can override this to alter the behavior when the ref count
// reaches 0. The default implementation calls Quit on the main message loop
// which causes the process to shutdown. Note, this can be called on any
// thread. (See ReleaseProcess)
virtual void OnFinalRelease();
private:
// NOTE: make sure that child_thread_ is listed before shutdown_event_, since
// it depends on it (indirectly through IPC::SyncChannel).
scoped_ptr<ChildThread> child_thread_;
base::AtomicRefCount ref_count_;
// An event that will be signalled when we shutdown.
base::WaitableEvent shutdown_event_;
// The singleton instance for this process.
static ChildProcess* child_process_;
DISALLOW_EVIL_CONSTRUCTORS(ChildProcess);
};
#endif // CHROME_COMMON_CHILD_PROCESS_H__
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