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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 #ifndef BASE_FILES_IMPORTANT_FILE_WRITER_H_ | 5 #ifndef BASE_FILES_IMPORTANT_FILE_WRITER_H_ |
6 #define BASE_FILES_IMPORTANT_FILE_WRITER_H_ | 6 #define BASE_FILES_IMPORTANT_FILE_WRITER_H_ |
7 | 7 |
8 #include <string> | 8 #include <string> |
9 | 9 |
10 #include "base/base_export.h" | 10 #include "base/base_export.h" |
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55 // Save |data| to |path| in an atomic manner (see the class comment above). | 55 // Save |data| to |path| in an atomic manner (see the class comment above). |
56 // Blocks and writes data on the current thread. | 56 // Blocks and writes data on the current thread. |
57 static bool WriteFileAtomically(const FilePath& path, | 57 static bool WriteFileAtomically(const FilePath& path, |
58 const std::string& data); | 58 const std::string& data); |
59 | 59 |
60 // Initialize the writer. | 60 // Initialize the writer. |
61 // |path| is the name of file to write. | 61 // |path| is the name of file to write. |
62 // |task_runner| is the SequencedTaskRunner instance where on which we will | 62 // |task_runner| is the SequencedTaskRunner instance where on which we will |
63 // execute file I/O operations. | 63 // execute file I/O operations. |
64 // All non-const methods, ctor and dtor must be called on the same thread. | 64 // All non-const methods, ctor and dtor must be called on the same thread. |
65 ImportantFileWriter( | 65 ImportantFileWriter(const FilePath& path, |
66 const FilePath& path, | 66 const scoped_refptr<SequencedTaskRunner>& task_runner); |
67 const scoped_refptr<base::SequencedTaskRunner>& task_runner); | 67 |
| 68 // Same as above, but with a custom commit interval. |
| 69 ImportantFileWriter(const FilePath& path, |
| 70 const scoped_refptr<SequencedTaskRunner>& task_runner, |
| 71 TimeDelta interval); |
68 | 72 |
69 // You have to ensure that there are no pending writes at the moment | 73 // You have to ensure that there are no pending writes at the moment |
70 // of destruction. | 74 // of destruction. |
71 ~ImportantFileWriter(); | 75 ~ImportantFileWriter(); |
72 | 76 |
73 const FilePath& path() const { return path_; } | 77 const FilePath& path() const { return path_; } |
74 | 78 |
75 // Returns true if there is a scheduled write pending which has not yet | 79 // Returns true if there is a scheduled write pending which has not yet |
76 // been started. | 80 // been started. |
77 bool HasPendingWrite() const; | 81 bool HasPendingWrite() const; |
78 | 82 |
79 // Save |data| to target filename. Does not block. If there is a pending write | 83 // Save |data| to target filename. Does not block. If there is a pending write |
80 // scheduled by ScheduleWrite, it is cancelled. | 84 // scheduled by ScheduleWrite(), it is cancelled. |
81 void WriteNow(scoped_ptr<std::string> data); | 85 void WriteNow(scoped_ptr<std::string> data); |
82 | 86 |
83 // Schedule a save to target filename. Data will be serialized and saved | 87 // Schedule a save to target filename. Data will be serialized and saved |
84 // to disk after the commit interval. If another ScheduleWrite is issued | 88 // to disk after the commit interval. If another ScheduleWrite is issued |
85 // before that, only one serialization and write to disk will happen, and | 89 // before that, only one serialization and write to disk will happen, and |
86 // the most recent |serializer| will be used. This operation does not block. | 90 // the most recent |serializer| will be used. This operation does not block. |
87 // |serializer| should remain valid through the lifetime of | 91 // |serializer| should remain valid through the lifetime of |
88 // ImportantFileWriter. | 92 // ImportantFileWriter. |
89 void ScheduleWrite(DataSerializer* serializer); | 93 void ScheduleWrite(DataSerializer* serializer); |
90 | 94 |
91 // Serialize data pending to be saved and execute write on backend thread. | 95 // Serialize data pending to be saved and execute write on backend thread. |
92 void DoScheduledWrite(); | 96 void DoScheduledWrite(); |
93 | 97 |
94 // Registers |on_next_successful_write| to be called once, on the next | 98 // Registers |on_next_successful_write| to be called once, on the next |
95 // successful write event. Only one callback can be set at once. | 99 // successful write event. Only one callback can be set at once. |
96 void RegisterOnNextSuccessfulWriteCallback( | 100 void RegisterOnNextSuccessfulWriteCallback( |
97 const base::Closure& on_next_successful_write); | 101 const Closure& on_next_successful_write); |
98 | 102 |
99 TimeDelta commit_interval() const { | 103 TimeDelta commit_interval() const { |
100 return commit_interval_; | 104 return commit_interval_; |
101 } | 105 } |
102 | 106 |
103 void set_commit_interval(const TimeDelta& interval) { | |
104 commit_interval_ = interval; | |
105 } | |
106 | |
107 private: | 107 private: |
108 // Helper method for WriteNow(). | 108 // Helper method for WriteNow(). |
109 bool PostWriteTask(const Callback<bool()>& task); | 109 bool PostWriteTask(const Callback<bool()>& task); |
110 | 110 |
111 // If |result| is true and |on_next_successful_write_| is set, invokes | 111 // If |result| is true and |on_next_successful_write_| is set, invokes |
112 // |on_successful_write_| and then resets it; no-ops otherwise. | 112 // |on_successful_write_| and then resets it; no-ops otherwise. |
113 void ForwardSuccessfulWrite(bool result); | 113 void ForwardSuccessfulWrite(bool result); |
114 | 114 |
115 // Invoked once and then reset on the next successful write event. | 115 // Invoked once and then reset on the next successful write event. |
116 base::Closure on_next_successful_write_; | 116 Closure on_next_successful_write_; |
117 | 117 |
118 // Path being written to. | 118 // Path being written to. |
119 const FilePath path_; | 119 const FilePath path_; |
120 | 120 |
121 // TaskRunner for the thread on which file I/O can be done. | 121 // TaskRunner for the thread on which file I/O can be done. |
122 const scoped_refptr<base::SequencedTaskRunner> task_runner_; | 122 const scoped_refptr<SequencedTaskRunner> task_runner_; |
123 | 123 |
124 // Timer used to schedule commit after ScheduleWrite. | 124 // Timer used to schedule commit after ScheduleWrite. |
125 OneShotTimer<ImportantFileWriter> timer_; | 125 OneShotTimer<ImportantFileWriter> timer_; |
126 | 126 |
127 // Serializer which will provide the data to be saved. | 127 // Serializer which will provide the data to be saved. |
128 DataSerializer* serializer_; | 128 DataSerializer* serializer_; |
129 | 129 |
130 // Time delta after which scheduled data will be written to disk. | 130 // Time delta after which scheduled data will be written to disk. |
131 TimeDelta commit_interval_; | 131 const TimeDelta commit_interval_; |
132 | 132 |
133 WeakPtrFactory<ImportantFileWriter> weak_factory_; | 133 WeakPtrFactory<ImportantFileWriter> weak_factory_; |
134 | 134 |
135 DISALLOW_COPY_AND_ASSIGN(ImportantFileWriter); | 135 DISALLOW_COPY_AND_ASSIGN(ImportantFileWriter); |
136 }; | 136 }; |
137 | 137 |
138 } // namespace base | 138 } // namespace base |
139 | 139 |
140 #endif // BASE_FILES_IMPORTANT_FILE_WRITER_H_ | 140 #endif // BASE_FILES_IMPORTANT_FILE_WRITER_H_ |
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