1ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// Copyright (c) 2011 The Chromium Authors. All rights reserved. 2ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// Use of this source code is governed by a BSD-style license that can be 3ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// found in the LICENSE file. 4ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 5ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// This module provides a way to monitor a file or directory for changes. 6ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 7ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#ifndef BASE_FILES_FILE_PATH_WATCHER_H_ 8ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#define BASE_FILES_FILE_PATH_WATCHER_H_ 9ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#pragma once 10ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 11ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#include "base/basictypes.h" 12ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#include "base/file_path.h" 13ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#include "base/memory/ref_counted.h" 14ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#include "base/message_loop_proxy.h" 15ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 16ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsennamespace base { 17ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsennamespace files { 18ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 19ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// This class lets you register interest in changes on a FilePath. 20ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// The delegate will get called whenever the file or directory referenced by the 21ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// FilePath is changed, including created or deleted. Due to limitations in the 22ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// underlying OS APIs, FilePathWatcher has slightly different semantics on OS X 23ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// than on Windows or Linux. FilePathWatcher on Linux and Windows will detect 24ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// modifications to files in a watched directory. FilePathWatcher on Mac will 25ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// detect the creation and deletion of files in a watched directory, but will 26ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// not detect modifications to those files. See file_path_watcher_mac.cc for 27ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen// details. 28ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsenclass FilePathWatcher { 29ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen public: 30ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Declares the callback client code implements to receive notifications. Note 31ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // that implementations of this interface should not keep a reference to the 32ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // corresponding FileWatcher object to prevent a reference cycle. 33ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen class Delegate : public base::RefCountedThreadSafe<Delegate> { 34ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen public: 35ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual ~Delegate() {} 36ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual void OnFilePathChanged(const FilePath& path) = 0; 37ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Called when platform specific code detected an error. The watcher will 38ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // not call OnFilePathChanged for future changes. 39ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual void OnFilePathError(const FilePath& path) {} 40ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen }; 41ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 42ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen FilePathWatcher(); 43ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen ~FilePathWatcher(); 44ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 45ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Register interest in any changes on |path|. OnPathChanged will be called 46ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // back for each change. Returns true on success. 47ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // OnFilePathChanged() will be called on the same thread as Watch() is called, 48ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // which should have a MessageLoop of TYPE_IO. 49ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen bool Watch(const FilePath& path, Delegate* delegate) WARN_UNUSED_RESULT; 50ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 51ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen class PlatformDelegate; 52ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 53ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // A custom Task that always cleans up the PlatformDelegate, either when 54ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // executed or when deleted without having been executed at all, as can 55ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // happen during shutdown. 56ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen class CancelTask : public Task { 57ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen public: 58ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen CancelTask(PlatformDelegate* delegate): delegate_(delegate) {} 59ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual ~CancelTask() { 60ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen delegate_->CancelOnMessageLoopThread(); 61ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen } 62ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 63ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual void Run() { 64ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen delegate_->CancelOnMessageLoopThread(); 65ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen } 66ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen private: 67ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen scoped_refptr<PlatformDelegate> delegate_; 68ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 69ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen DISALLOW_COPY_AND_ASSIGN(CancelTask); 70ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen }; 71ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 72ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Used internally to encapsulate different members on different platforms. 73ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen class PlatformDelegate : public base::RefCountedThreadSafe<PlatformDelegate> { 74ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen public: 75ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen PlatformDelegate(); 76ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 77ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Start watching for the given |path| and notify |delegate| about changes. 78ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual bool Watch(const FilePath& path, 79ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen Delegate* delegate) WARN_UNUSED_RESULT = 0; 80ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 81ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Stop watching. This is called from FilePathWatcher's dtor in order to 82ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // allow to shut down properly while the object is still alive. 83ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // It can be called from any thread. 84ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual void Cancel() = 0; 85ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 86ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen protected: 87ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual ~PlatformDelegate(); 88ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 89ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Stop watching. This is only called on the thread of the appropriate 90ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // message loop. Since it can also be called more than once, it should 91ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // check |is_cancelled()| to avoid duplicate work. 92ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen virtual void CancelOnMessageLoopThread() = 0; 93ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 94ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen scoped_refptr<base::MessageLoopProxy> message_loop() const { 95ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen return message_loop_; 96ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen } 97ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 98ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen void set_message_loop(base::MessageLoopProxy* loop) { 99ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen message_loop_ = loop; 100ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen } 101ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 102ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen // Must be called before the PlatformDelegate is deleted. 103ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen void set_cancelled() { 104ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen cancelled_ = true; 105ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen } 106ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 107ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen bool is_cancelled() const { 108ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen return cancelled_; 109ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen } 110ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 111ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen private: 112ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen friend class base::RefCountedThreadSafe<PlatformDelegate>; 113ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen friend class CancelTask; 114ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 115ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen scoped_refptr<base::MessageLoopProxy> message_loop_; 116ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen bool cancelled_; 117ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen }; 118ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 119ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen private: 120ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen scoped_refptr<PlatformDelegate> impl_; 121ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 122ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen DISALLOW_COPY_AND_ASSIGN(FilePathWatcher); 123ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen}; 124ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 125ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen} // namespace files 126ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen} // namespace base 127ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen 128ddb351dbec246cf1fab5ec20d2d5520909041de1Kristian Monsen#endif // BASE_FILES_FILE_PATH_WATCHER_H_ 129