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Side by Side Diff: net/disk_cache/blockfile/block_files.h

Issue 992733002: Remove //net (except for Android test stuff) and sdch (Closed) Base URL: git@github.com:domokit/mojo.git@master
Patch Set: Created 5 years, 9 months ago
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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.
6
7 #ifndef NET_DISK_CACHE_BLOCKFILE_BLOCK_FILES_H_
8 #define NET_DISK_CACHE_BLOCKFILE_BLOCK_FILES_H_
9
10 #include <vector>
11
12 #include "base/files/file_path.h"
13 #include "base/gtest_prod_util.h"
14 #include "base/memory/scoped_ptr.h"
15 #include "net/base/net_export.h"
16 #include "net/disk_cache/blockfile/addr.h"
17 #include "net/disk_cache/blockfile/disk_format_base.h"
18 #include "net/disk_cache/blockfile/mapped_file.h"
19
20 namespace base {
21 class ThreadChecker;
22 }
23
24 namespace disk_cache {
25
26 // An instance of this class represents the header of a block file in memory.
27 // Note that this class doesn't perform any file operation (as in it only deals
28 // with entities in memory).
29 // The header of a block file (and hence, this object) is all that is needed to
30 // perform common operations like allocating or releasing space for storage;
31 // actual access to that storage, however, is not performed through this class.
32 class NET_EXPORT_PRIVATE BlockHeader {
33 public:
34 BlockHeader();
35 explicit BlockHeader(BlockFileHeader* header);
36 explicit BlockHeader(MappedFile* file);
37 BlockHeader(const BlockHeader& other);
38 ~BlockHeader();
39
40 // Creates a new entry of |size| blocks on the allocation map, updating the
41 // apropriate counters.
42 bool CreateMapBlock(int size, int* index);
43
44 // Deletes the block pointed by |index|.
45 void DeleteMapBlock(int index, int block_size);
46
47 // Returns true if the specified block is used.
48 bool UsedMapBlock(int index, int size);
49
50 // Restores the "empty counters" and allocation hints.
51 void FixAllocationCounters();
52
53 // Returns true if the current block file should not be used as-is to store
54 // more records. |block_count| is the number of blocks to allocate.
55 bool NeedToGrowBlockFile(int block_count) const;
56
57 // Returns true if this block file can be used to store an extra record of
58 // size |block_count|.
59 bool CanAllocate(int block_count) const;
60
61 // Returns the number of empty blocks for this file.
62 int EmptyBlocks() const;
63
64 // Returns the minumum number of allocations that can be satisfied.
65 int MinimumAllocations() const;
66
67 // Returns the number of blocks that this file can store.
68 int Capacity() const;
69
70 // Returns true if the counters look OK.
71 bool ValidateCounters() const;
72
73 // Returns the identifiers of this and the next file (0 if there is none).
74 int FileId() const;
75 int NextFileId() const;
76
77 // Returns the size of the wrapped structure (BlockFileHeader).
78 int Size() const;
79
80 // Returns a pointer to the underlying BlockFileHeader.
81 // TODO(rvargas): This may be removed with the support for V2.
82 BlockFileHeader* Header();
83
84 private:
85 BlockFileHeader* header_;
86 };
87
88 typedef std::vector<BlockHeader> BlockFilesBitmaps;
89
90 // This class handles the set of block-files open by the disk cache.
91 class NET_EXPORT_PRIVATE BlockFiles {
92 public:
93 explicit BlockFiles(const base::FilePath& path);
94 ~BlockFiles();
95
96 // Performs the object initialization. create_files indicates if the backing
97 // files should be created or just open.
98 bool Init(bool create_files);
99
100 // Returns the file that stores a given address.
101 MappedFile* GetFile(Addr address);
102
103 // Creates a new entry on a block file. block_type indicates the size of block
104 // to be used (as defined on cache_addr.h), block_count is the number of
105 // blocks to allocate, and block_address is the address of the new entry.
106 bool CreateBlock(FileType block_type, int block_count, Addr* block_address);
107
108 // Removes an entry from the block files. If deep is true, the storage is zero
109 // filled; otherwise the entry is removed but the data is not altered (must be
110 // already zeroed).
111 void DeleteBlock(Addr address, bool deep);
112
113 // Close all the files and set the internal state to be initializad again. The
114 // cache is being purged.
115 void CloseFiles();
116
117 // Sends UMA stats.
118 void ReportStats();
119
120 // Returns true if the blocks pointed by a given address are currently used.
121 // This method is only intended for debugging.
122 bool IsValid(Addr address);
123
124 private:
125 // Set force to true to overwrite the file if it exists.
126 bool CreateBlockFile(int index, FileType file_type, bool force);
127 bool OpenBlockFile(int index);
128
129 // Attemp to grow this file. Fails if the file cannot be extended anymore.
130 bool GrowBlockFile(MappedFile* file, BlockFileHeader* header);
131
132 // Returns the appropriate file to use for a new block.
133 MappedFile* FileForNewBlock(FileType block_type, int block_count);
134
135 // Returns the next block file on this chain, creating new files if needed.
136 MappedFile* NextFile(MappedFile* file);
137
138 // Creates an empty block file and returns its index.
139 int16 CreateNextBlockFile(FileType block_type);
140
141 // Removes a chained block file that is now empty.
142 bool RemoveEmptyFile(FileType block_type);
143
144 // Restores the header of a potentially inconsistent file.
145 bool FixBlockFileHeader(MappedFile* file);
146
147 // Retrieves stats for the given file index.
148 void GetFileStats(int index, int* used_count, int* load);
149
150 // Returns the filename for a given file index.
151 base::FilePath Name(int index);
152
153 bool init_;
154 char* zero_buffer_; // Buffer to speed-up cleaning deleted entries.
155 base::FilePath path_; // Path to the backing folder.
156 std::vector<MappedFile*> block_files_; // The actual files.
157 scoped_ptr<base::ThreadChecker> thread_checker_;
158
159 FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_ZeroSizeFile);
160 FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_TruncatedFile);
161 FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_InvalidFile);
162 FRIEND_TEST_ALL_PREFIXES(DiskCacheTest, BlockFiles_Stats);
163
164 DISALLOW_COPY_AND_ASSIGN(BlockFiles);
165 };
166
167 } // namespace disk_cache
168
169 #endif // NET_DISK_CACHE_BLOCKFILE_BLOCK_FILES_H_
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