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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 NET_DISK_CACHE_FLASH_LOG_STRUCTURED_STORE_H_ | 5 #ifndef NET_DISK_CACHE_FLASH_LOG_STORE_H_ |
6 #define NET_DISK_CACHE_FLASH_LOG_STRUCTURED_STORE_H_ | 6 #define NET_DISK_CACHE_FLASH_LOG_STORE_H_ |
7 | 7 |
8 #include <set> | 8 #include <set> |
9 #include <vector> | 9 #include <vector> |
10 | 10 |
11 #include "base/basictypes.h" | 11 #include "base/basictypes.h" |
12 #include "base/gtest_prod_util.h" | 12 #include "base/gtest_prod_util.h" |
13 #include "net/base/net_export.h" | 13 #include "net/base/net_export.h" |
14 | 14 |
15 namespace disk_cache { | 15 namespace disk_cache { |
16 | 16 |
17 class Segment; | 17 class Segment; |
18 class Storage; | 18 class Storage; |
19 | 19 |
20 // This class implements a general purpose store for storing and retrieving | 20 // This class implements a general purpose store for storing and retrieving |
21 // entries consisting of arbitrary binary data. The store has log semantics, | 21 // entries consisting of arbitrary binary data. The store has log semantics, |
22 // i.e. it's not possible to overwrite data in place. In order to update an | 22 // i.e. it's not possible to overwrite data in place. In order to update an |
23 // entry, a new version must be written. Only one entry can be written to at | 23 // entry, a new version must be written. Only one entry can be written to at |
24 // any given time, while concurrent reading of multiple entries is supported. | 24 // any given time, while concurrent reading of multiple entries is supported. |
25 class NET_EXPORT_PRIVATE LogStructuredStore { | 25 class NET_EXPORT_PRIVATE LogStore { |
26 public: | 26 public: |
27 explicit LogStructuredStore(Storage* storage); | 27 explicit LogStore(Storage* storage); |
28 ~LogStructuredStore(); | 28 ~LogStore(); |
29 | 29 |
30 // Performs initialization. Must be the first function called and further | 30 // Performs initialization. Must be the first function called and further |
31 // calls should be made only if it is successful. | 31 // calls should be made only if it is successful. |
32 bool Init(); | 32 bool Init(); |
33 | 33 |
34 // Closes the store. Should be the last function called before destruction. | 34 // Closes the store. Should be the last function called before destruction. |
35 bool Close(); | 35 bool Close(); |
36 | 36 |
37 // Creates an entry of |size| bytes. The id of the created entry is stored in | 37 // Creates an entry of |size| bytes. The id of the created entry is stored in |
38 // |entry_id|. | 38 // |entry_id|. |
(...skipping 10 matching lines...) Expand all Loading... |
49 // Reads |size| bytes starting from |offset| into |buffer|, where |offset| is | 49 // Reads |size| bytes starting from |offset| into |buffer|, where |offset| is |
50 // relative to the entry's content, from an entry identified by |entry_id|. | 50 // relative to the entry's content, from an entry identified by |entry_id|. |
51 bool ReadData(int32 entry_id, void* buffer, int32 size, int32 offset) const; | 51 bool ReadData(int32 entry_id, void* buffer, int32 size, int32 offset) const; |
52 | 52 |
53 // Closes an entry that was either opened with OpenEntry or created with | 53 // Closes an entry that was either opened with OpenEntry or created with |
54 // CreateEntry. | 54 // CreateEntry. |
55 void CloseEntry(int32 id); | 55 void CloseEntry(int32 id); |
56 | 56 |
57 private: | 57 private: |
58 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, | 58 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, |
59 LogStructuredStoreReadFromClosedSegment); | 59 LogStoreReadFromClosedSegment); |
60 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, | 60 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, |
61 LogStructuredStoreSegmentSelectionIsFifo); | 61 LogStoreSegmentSelectionIsFifo); |
62 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, | 62 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, |
63 LogStructuredStoreInUseSegmentIsSkipped); | 63 LogStoreInUseSegmentIsSkipped); |
64 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, | 64 FRIEND_TEST_ALL_PREFIXES(FlashCacheTest, |
65 LogStructuredStoreReadFromCurrentAfterClose); | 65 LogStoreReadFromCurrentAfterClose); |
66 | 66 |
67 int32 GetNextSegmentIndex(); | 67 int32 GetNextSegmentIndex(); |
68 bool InUse(int32 segment_index) const; | 68 bool InUse(int32 segment_index) const; |
69 | 69 |
70 Storage* storage_; | 70 Storage* storage_; |
71 | 71 |
72 int32 num_segments_; | 72 int32 num_segments_; |
73 | 73 |
74 // Currently open segments, either for reading or writing. There can only be | 74 // Currently open segments, either for reading or writing. There can only be |
75 // one segment open for writing, and multiple open for reading. | 75 // one segment open for writing, and multiple open for reading. |
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87 int32 current_entry_id_; | 87 int32 current_entry_id_; |
88 | 88 |
89 // Number of bytes left to be written to the entry identified by | 89 // Number of bytes left to be written to the entry identified by |
90 // |current_entry_id_|. Its value makes sense iff |current_entry_id_| is not | 90 // |current_entry_id_|. Its value makes sense iff |current_entry_id_| is not |
91 // -1. | 91 // -1. |
92 int32 current_entry_num_bytes_left_to_write_; | 92 int32 current_entry_num_bytes_left_to_write_; |
93 | 93 |
94 bool init_; // Init was called. | 94 bool init_; // Init was called. |
95 bool closed_; // Close was called. | 95 bool closed_; // Close was called. |
96 | 96 |
97 DISALLOW_COPY_AND_ASSIGN(LogStructuredStore); | 97 DISALLOW_COPY_AND_ASSIGN(LogStore); |
98 }; | 98 }; |
99 | 99 |
100 } // namespace disk_cache | 100 } // namespace disk_cache |
101 | 101 |
102 #endif // NET_DISK_CACHE_FLASH_LOG_STRUCTURED_STORE_H_ | 102 #endif // NET_DISK_CACHE_FLASH_LOG_STORE_H_ |
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