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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_MEMORY_MEM_BACKEND_IMPL_H_ | |
8 #define NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_ | |
9 | |
10 #include "base/compiler_specific.h" | |
11 #include "base/containers/hash_tables.h" | |
12 #include "base/memory/weak_ptr.h" | |
13 #include "net/disk_cache/disk_cache.h" | |
14 #include "net/disk_cache/memory/mem_rankings.h" | |
15 | |
16 namespace net { | |
17 class NetLog; | |
18 } // namespace net | |
19 | |
20 namespace disk_cache { | |
21 | |
22 class MemEntryImpl; | |
23 | |
24 // This class implements the Backend interface. An object of this class handles | |
25 // the operations of the cache without writing to disk. | |
26 class NET_EXPORT_PRIVATE MemBackendImpl : public Backend { | |
27 public: | |
28 explicit MemBackendImpl(net::NetLog* net_log); | |
29 ~MemBackendImpl() override; | |
30 | |
31 // Returns an instance of a Backend implemented only in memory. The returned | |
32 // object should be deleted when not needed anymore. max_bytes is the maximum | |
33 // size the cache can grow to. If zero is passed in as max_bytes, the cache | |
34 // will determine the value to use based on the available memory. The returned | |
35 // pointer can be NULL if a fatal error is found. | |
36 static scoped_ptr<Backend> CreateBackend(int max_bytes, net::NetLog* net_log); | |
37 | |
38 // Performs general initialization for this current instance of the cache. | |
39 bool Init(); | |
40 | |
41 // Sets the maximum size for the total amount of data stored by this instance. | |
42 bool SetMaxSize(int max_bytes); | |
43 | |
44 // Permanently deletes an entry. | |
45 void InternalDoomEntry(MemEntryImpl* entry); | |
46 | |
47 // Updates the ranking information for an entry. | |
48 void UpdateRank(MemEntryImpl* node); | |
49 | |
50 // A user data block is being created, extended or truncated. | |
51 void ModifyStorageSize(int32 old_size, int32 new_size); | |
52 | |
53 // Returns the maximum size for a file to reside on the cache. | |
54 int MaxFileSize() const; | |
55 | |
56 // Insert an MemEntryImpl into the ranking list. This method is only called | |
57 // from MemEntryImpl to insert child entries. The reference can be removed | |
58 // by calling RemoveFromRankingList(|entry|). | |
59 void InsertIntoRankingList(MemEntryImpl* entry); | |
60 | |
61 // Remove |entry| from ranking list. This method is only called from | |
62 // MemEntryImpl to remove a child entry from the ranking list. | |
63 void RemoveFromRankingList(MemEntryImpl* entry); | |
64 | |
65 // Backend interface. | |
66 net::CacheType GetCacheType() const override; | |
67 int32 GetEntryCount() const override; | |
68 int OpenEntry(const std::string& key, | |
69 Entry** entry, | |
70 const CompletionCallback& callback) override; | |
71 int CreateEntry(const std::string& key, | |
72 Entry** entry, | |
73 const CompletionCallback& callback) override; | |
74 int DoomEntry(const std::string& key, | |
75 const CompletionCallback& callback) override; | |
76 int DoomAllEntries(const CompletionCallback& callback) override; | |
77 int DoomEntriesBetween(base::Time initial_time, | |
78 base::Time end_time, | |
79 const CompletionCallback& callback) override; | |
80 int DoomEntriesSince(base::Time initial_time, | |
81 const CompletionCallback& callback) override; | |
82 scoped_ptr<Iterator> CreateIterator() override; | |
83 void GetStats( | |
84 std::vector<std::pair<std::string, std::string>>* stats) override {} | |
85 void OnExternalCacheHit(const std::string& key) override; | |
86 | |
87 private: | |
88 class MemIterator; | |
89 friend class MemIterator; | |
90 | |
91 typedef base::hash_map<std::string, MemEntryImpl*> EntryMap; | |
92 | |
93 // Old Backend interface. | |
94 bool OpenEntry(const std::string& key, Entry** entry); | |
95 bool CreateEntry(const std::string& key, Entry** entry); | |
96 bool DoomEntry(const std::string& key); | |
97 bool DoomAllEntries(); | |
98 bool DoomEntriesBetween(const base::Time initial_time, | |
99 const base::Time end_time); | |
100 bool DoomEntriesSince(const base::Time initial_time); | |
101 | |
102 // Deletes entries from the cache until the current size is below the limit. | |
103 // If empty is true, the whole cache will be trimmed, regardless of being in | |
104 // use. | |
105 void TrimCache(bool empty); | |
106 | |
107 // Handles the used storage count. | |
108 void AddStorageSize(int32 bytes); | |
109 void SubstractStorageSize(int32 bytes); | |
110 | |
111 EntryMap entries_; | |
112 MemRankings rankings_; // Rankings to be able to trim the cache. | |
113 int32 max_size_; // Maximum data size for this instance. | |
114 int32 current_size_; | |
115 | |
116 net::NetLog* net_log_; | |
117 | |
118 base::WeakPtrFactory<MemBackendImpl> weak_factory_; | |
119 | |
120 DISALLOW_COPY_AND_ASSIGN(MemBackendImpl); | |
121 }; | |
122 | |
123 } // namespace disk_cache | |
124 | |
125 #endif // NET_DISK_CACHE_MEMORY_MEM_BACKEND_IMPL_H_ | |
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