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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 | |
3 // found in the LICENSE file. | |
4 | |
5 // See net/disk_cache/disk_cache.h for the public interface of the cache. | |
6 | |
7 #ifndef NET_DISK_CACHE_BLOCKFILE_FILE_H_ | |
8 #define NET_DISK_CACHE_BLOCKFILE_FILE_H_ | |
9 | |
10 #include "base/files/file.h" | |
11 #include "base/memory/ref_counted.h" | |
12 #include "net/base/net_export.h" | |
13 | |
14 namespace base { | |
15 class FilePath; | |
16 } | |
17 | |
18 namespace disk_cache { | |
19 | |
20 // This interface is used to support asynchronous ReadData and WriteData calls. | |
21 class FileIOCallback { | |
22 public: | |
23 // Notified of the actual number of bytes read or written. This value is | |
24 // negative if an error occurred. | |
25 virtual void OnFileIOComplete(int bytes_copied) = 0; | |
26 | |
27 protected: | |
28 virtual ~FileIOCallback() {} | |
29 }; | |
30 | |
31 // Simple wrapper around a file that allows asynchronous operations. | |
32 class NET_EXPORT_PRIVATE File : public base::RefCounted<File> { | |
33 friend class base::RefCounted<File>; | |
34 public: | |
35 File(); | |
36 // mixed_mode set to true enables regular synchronous operations for the file. | |
37 explicit File(bool mixed_mode); | |
38 | |
39 // Initializes the object to use the passed in file instead of opening it with | |
40 // the Init() call. No asynchronous operations can be performed with this | |
41 // object. | |
42 explicit File(base::File file); | |
43 | |
44 // Initializes the object to point to a given file. The file must aready exist | |
45 // on disk, and allow shared read and write. | |
46 bool Init(const base::FilePath& name); | |
47 | |
48 // Returns true if the file was opened properly. | |
49 bool IsValid() const; | |
50 | |
51 // Performs synchronous IO. | |
52 bool Read(void* buffer, size_t buffer_len, size_t offset); | |
53 bool Write(const void* buffer, size_t buffer_len, size_t offset); | |
54 | |
55 // Performs asynchronous IO. callback will be called when the IO completes, | |
56 // as an APC on the thread that queued the operation. | |
57 bool Read(void* buffer, size_t buffer_len, size_t offset, | |
58 FileIOCallback* callback, bool* completed); | |
59 bool Write(const void* buffer, size_t buffer_len, size_t offset, | |
60 FileIOCallback* callback, bool* completed); | |
61 | |
62 // Sets the file's length. The file is truncated or extended with zeros to | |
63 // the new length. | |
64 bool SetLength(size_t length); | |
65 size_t GetLength(); | |
66 | |
67 // Blocks until |num_pending_io| IO operations complete. | |
68 static void WaitForPendingIO(int* num_pending_io); | |
69 | |
70 // Drops current pending operations without waiting for them to complete. | |
71 static void DropPendingIO(); | |
72 | |
73 protected: | |
74 virtual ~File(); | |
75 | |
76 // Returns the handle or file descriptor. | |
77 base::PlatformFile platform_file() const; | |
78 | |
79 private: | |
80 // Performs the actual asynchronous write. If notify is set and there is no | |
81 // callback, the call will be re-synchronized. | |
82 bool AsyncWrite(const void* buffer, size_t buffer_len, size_t offset, | |
83 FileIOCallback* callback, bool* completed); | |
84 | |
85 // Infrastructure for async IO. | |
86 int DoRead(void* buffer, size_t buffer_len, size_t offset); | |
87 int DoWrite(const void* buffer, size_t buffer_len, size_t offset); | |
88 void OnOperationComplete(FileIOCallback* callback, int result); | |
89 | |
90 bool init_; | |
91 bool mixed_; | |
92 base::File base_file_; // Regular, asynchronous IO handle. | |
93 base::File sync_base_file_; // Synchronous IO handle. | |
94 | |
95 DISALLOW_COPY_AND_ASSIGN(File); | |
96 }; | |
97 | |
98 } // namespace disk_cache | |
99 | |
100 #endif // NET_DISK_CACHE_BLOCKFILE_FILE_H_ | |
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