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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 | 4 |
5 // This module provides a way to monitor a file or directory for changes. | 5 // This module provides a way to monitor a file or directory for changes. |
6 | 6 |
7 #ifndef BASE_FILES_FILE_PATH_WATCHER_H_ | 7 #ifndef BASE_FILES_FILE_PATH_WATCHER_H_ |
8 #define BASE_FILES_FILE_PATH_WATCHER_H_ | 8 #define BASE_FILES_FILE_PATH_WATCHER_H_ |
9 | 9 |
10 #include "base/base_export.h" | 10 #include "base/base_export.h" |
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26 // detect the creation and deletion of files in a watched directory, but will | 26 // detect the creation and deletion of files in a watched directory, but will |
27 // not detect modifications to those files. See file_path_watcher_kqueue.cc for | 27 // not detect modifications to those files. See file_path_watcher_kqueue.cc for |
28 // details. | 28 // details. |
29 class BASE_EXPORT FilePathWatcher { | 29 class BASE_EXPORT FilePathWatcher { |
30 public: | 30 public: |
31 // Callback type for Watch(). |path| points to the file that was updated, | 31 // Callback type for Watch(). |path| points to the file that was updated, |
32 // and |error| is true if the platform specific code detected an error. In | 32 // and |error| is true if the platform specific code detected an error. In |
33 // that case, the callback won't be invoked again. | 33 // that case, the callback won't be invoked again. |
34 typedef base::Callback<void(const FilePath& path, bool error)> Callback; | 34 typedef base::Callback<void(const FilePath& path, bool error)> Callback; |
35 | 35 |
36 // Declares the callback client code implements to receive notifications. Note | |
37 // that implementations of this interface should not keep a reference to the | |
38 // corresponding FileWatcher object to prevent a reference cycle. | |
39 // | |
40 // Deprecated: see comment on Watch() below. | |
41 class Delegate : public base::RefCountedThreadSafe<Delegate> { | |
42 public: | |
43 virtual void OnFilePathChanged(const FilePath& path) = 0; | |
44 // Called when platform specific code detected an error. The watcher will | |
45 // not call OnFilePathChanged for future changes. | |
46 virtual void OnFilePathError(const FilePath& path) {} | |
47 | |
48 protected: | |
49 friend class base::RefCountedThreadSafe<Delegate>; | |
50 virtual ~Delegate() {} | |
51 }; | |
52 | |
53 // Used internally to encapsulate different members on different platforms. | 36 // Used internally to encapsulate different members on different platforms. |
54 // TODO(jhawkins): Move this into its own file. Also fix the confusing naming | 37 // TODO(jhawkins): Move this into its own file. Also fix the confusing naming |
55 // wrt Delegate vs PlatformDelegate. | 38 // wrt Delegate vs PlatformDelegate. |
56 class PlatformDelegate : public base::RefCountedThreadSafe<PlatformDelegate> { | 39 class PlatformDelegate : public base::RefCountedThreadSafe<PlatformDelegate> { |
57 public: | 40 public: |
58 PlatformDelegate(); | 41 PlatformDelegate(); |
59 | 42 |
60 // Start watching for the given |path| and notify |delegate| about changes. | 43 // Start watching for the given |path| and notify |delegate| about changes. |
61 virtual bool Watch(const FilePath& path, | 44 virtual bool Watch(const FilePath& path, |
62 bool recursive, | 45 bool recursive, |
63 Delegate* delegate) WARN_UNUSED_RESULT = 0; | 46 const Callback& callback) WARN_UNUSED_RESULT = 0; |
64 | 47 |
65 // Stop watching. This is called from FilePathWatcher's dtor in order to | 48 // Stop watching. This is called from FilePathWatcher's dtor in order to |
66 // allow to shut down properly while the object is still alive. | 49 // allow to shut down properly while the object is still alive. |
67 // It can be called from any thread. | 50 // It can be called from any thread. |
68 virtual void Cancel() = 0; | 51 virtual void Cancel() = 0; |
69 | 52 |
70 protected: | 53 protected: |
71 friend class base::RefCountedThreadSafe<PlatformDelegate>; | 54 friend class base::RefCountedThreadSafe<PlatformDelegate>; |
72 friend class FilePathWatcher; | 55 friend class FilePathWatcher; |
73 | 56 |
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101 }; | 84 }; |
102 | 85 |
103 FilePathWatcher(); | 86 FilePathWatcher(); |
104 virtual ~FilePathWatcher(); | 87 virtual ~FilePathWatcher(); |
105 | 88 |
106 // A callback that always cleans up the PlatformDelegate, either when executed | 89 // A callback that always cleans up the PlatformDelegate, either when executed |
107 // or when deleted without having been executed at all, as can happen during | 90 // or when deleted without having been executed at all, as can happen during |
108 // shutdown. | 91 // shutdown. |
109 static void CancelWatch(const scoped_refptr<PlatformDelegate>& delegate); | 92 static void CancelWatch(const scoped_refptr<PlatformDelegate>& delegate); |
110 | 93 |
111 // Register interest in any changes on |path|. OnPathChanged will be called | |
112 // back for each change. Returns true on success. | |
113 // OnFilePathChanged() will be called on the same thread as Watch() is called, | |
114 // which should have a MessageLoop of TYPE_IO. | |
115 // | |
116 // Deprecated: new code should use the callback interface, declared below. | |
117 // The FilePathWatcher::Delegate interface will be removed once all client | |
118 // code has been updated. http://crbug.com/130980 | |
119 virtual bool Watch(const FilePath& path, Delegate* delegate) | |
120 WARN_UNUSED_RESULT; | |
121 | |
122 // Invokes |callback| whenever updates to |path| are detected. This should be | 94 // Invokes |callback| whenever updates to |path| are detected. This should be |
123 // called at most once, and from a MessageLoop of TYPE_IO. Set |recursive| to | 95 // called at most once, and from a MessageLoop of TYPE_IO. Set |recursive| to |
124 // true, to watch |path| and its children. The callback will be invoked on | 96 // true, to watch |path| and its children. The callback will be invoked on |
125 // the same loop. Returns true on success. | 97 // the same loop. Returns true on success. |
126 // | 98 // |
127 // NOTE: Recursive watch is not supported on all platforms and file systems. | 99 // NOTE: Recursive watch is not supported on all platforms and file systems. |
128 // Watch() will return false in the case of failure. | 100 // Watch() will return false in the case of failure. |
129 bool Watch(const FilePath& path, bool recursive, const Callback& callback); | 101 bool Watch(const FilePath& path, bool recursive, const Callback& callback); |
130 | 102 |
131 private: | 103 private: |
132 scoped_refptr<PlatformDelegate> impl_; | 104 scoped_refptr<PlatformDelegate> impl_; |
133 | 105 |
134 DISALLOW_COPY_AND_ASSIGN(FilePathWatcher); | 106 DISALLOW_COPY_AND_ASSIGN(FilePathWatcher); |
135 }; | 107 }; |
136 | 108 |
137 } // namespace files | 109 } // namespace files |
138 } // namespace base | 110 } // namespace base |
139 | 111 |
140 #endif // BASE_FILES_FILE_PATH_WATCHER_H_ | 112 #endif // BASE_FILES_FILE_PATH_WATCHER_H_ |
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