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Side by Side Diff: chrome/common/important_file_writer.h

Issue 11027070: Moved JsonPrefStore to use SequencedWorkerPool (Closed) Base URL: svn://svn.chromium.org/chrome/trunk/src
Patch Set: Created 8 years, 2 months ago
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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 CHROME_COMMON_IMPORTANT_FILE_WRITER_H_ 5 #ifndef CHROME_COMMON_IMPORTANT_FILE_WRITER_H_
6 #define CHROME_COMMON_IMPORTANT_FILE_WRITER_H_ 6 #define CHROME_COMMON_IMPORTANT_FILE_WRITER_H_
7 7
8 #include <string> 8 #include <string>
9 9
10 #include "base/basictypes.h" 10 #include "base/basictypes.h"
11 #include "base/file_path.h" 11 #include "base/file_path.h"
12 #include "base/memory/ref_counted.h" 12 #include "base/memory/ref_counted.h"
13 #include "base/threading/non_thread_safe.h" 13 #include "base/threading/non_thread_safe.h"
14 #include "base/time.h" 14 #include "base/time.h"
15 #include "base/timer.h" 15 #include "base/timer.h"
16 16
17 namespace base { 17 namespace base {
18 class MessageLoopProxy; 18 class SequencedTaskRunner;
19 class Thread; 19 class Thread;
20 } 20 }
21 21
22 // Helper to ensure that a file won't be corrupted by the write (for example on 22 // Helper to ensure that a file won't be corrupted by the write (for example on
23 // application crash). Consider a naive way to save an important file F: 23 // application crash). Consider a naive way to save an important file F:
24 // 24 //
25 // 1. Open F for writing, truncating it. 25 // 1. Open F for writing, truncating it.
26 // 2. Write new data to F. 26 // 2. Write new data to F.
27 // 27 //
28 // It's good when it works, but it gets very bad if step 2. doesn't complete. 28 // It's good when it works, but it gets very bad if step 2. doesn't complete.
(...skipping 16 matching lines...) Expand all
45 // serialization. Will be called on the same thread on which 45 // serialization. Will be called on the same thread on which
46 // ImportantFileWriter has been created. 46 // ImportantFileWriter has been created.
47 virtual bool SerializeData(std::string* data) = 0; 47 virtual bool SerializeData(std::string* data) = 0;
48 48
49 protected: 49 protected:
50 virtual ~DataSerializer() {} 50 virtual ~DataSerializer() {}
51 }; 51 };
52 52
53 // Initialize the writer. 53 // Initialize the writer.
54 // |path| is the name of file to write. 54 // |path| is the name of file to write.
55 // |file_message_loop_proxy| is the MessageLoopProxy for a thread on which 55 // |task_runner| is the SequencedTaskRunner instance where on which we will
56 // file I/O can be done. 56 // execute file I/O operations.
57 // All non-const methods, ctor and dtor must be called on the same thread. 57 // All non-const methods, ctor and dtor must be called on the same thread.
58 ImportantFileWriter(const FilePath& path, 58 ImportantFileWriter(const FilePath& path,
59 base::MessageLoopProxy* file_message_loop_proxy); 59 base::SequencedTaskRunner* task_runner);
60 60
61 // You have to ensure that there are no pending writes at the moment 61 // You have to ensure that there are no pending writes at the moment
62 // of destruction. 62 // of destruction.
63 ~ImportantFileWriter(); 63 ~ImportantFileWriter();
64 64
65 const FilePath& path() const { return path_; } 65 const FilePath& path() const { return path_; }
66 66
67 // Returns true if there is a scheduled write pending which has not yet 67 // Returns true if there is a scheduled write pending which has not yet
68 // been started. 68 // been started.
69 bool HasPendingWrite() const; 69 bool HasPendingWrite() const;
(...skipping 18 matching lines...) Expand all
88 } 88 }
89 89
90 void set_commit_interval(const base::TimeDelta& interval) { 90 void set_commit_interval(const base::TimeDelta& interval) {
91 commit_interval_ = interval; 91 commit_interval_ = interval;
92 } 92 }
93 93
94 private: 94 private:
95 // Path being written to. 95 // Path being written to.
96 const FilePath path_; 96 const FilePath path_;
97 97
98 // MessageLoopProxy for the thread on which file I/O can be done. 98 // TaskRunner for the thread on which file I/O can be done.
99 scoped_refptr<base::MessageLoopProxy> file_message_loop_proxy_; 99 scoped_refptr<base::SequencedTaskRunner> task_runner_;
akalin 2012/10/19 23:12:21 const
zel 2012/10/21 20:03:19 Done.
100 100
101 // Timer used to schedule commit after ScheduleWrite. 101 // Timer used to schedule commit after ScheduleWrite.
102 base::OneShotTimer<ImportantFileWriter> timer_; 102 base::OneShotTimer<ImportantFileWriter> timer_;
103 103
104 // Serializer which will provide the data to be saved. 104 // Serializer which will provide the data to be saved.
105 DataSerializer* serializer_; 105 DataSerializer* serializer_;
106 106
107 // Time delta after which scheduled data will be written to disk. 107 // Time delta after which scheduled data will be written to disk.
108 base::TimeDelta commit_interval_; 108 base::TimeDelta commit_interval_;
109 109
110 DISALLOW_COPY_AND_ASSIGN(ImportantFileWriter); 110 DISALLOW_COPY_AND_ASSIGN(ImportantFileWriter);
111 }; 111 };
112 112
113 #endif // CHROME_COMMON_IMPORTANT_FILE_WRITER_H_ 113 #endif // CHROME_COMMON_IMPORTANT_FILE_WRITER_H_
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