1 // Copyright (c) 2006-2009 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_MEM_BACKEND_IMPL_H__ 8 #define NET_DISK_CACHE_MEM_BACKEND_IMPL_H__ 9 10 #include "base/hash_tables.h" 11 12 #include "net/disk_cache/disk_cache.h" 13 #include "net/disk_cache/mem_rankings.h" 14 15 namespace disk_cache { 16 17 class MemEntryImpl; 18 19 // This class implements the Backend interface. An object of this class handles 20 // the operations of the cache without writing to disk. 21 class MemBackendImpl : public Backend { 22 public: 23 MemBackendImpl() : max_size_(0), current_size_(0) {} 24 ~MemBackendImpl(); 25 26 // Performs general initialization for this current instance of the cache. 27 bool Init(); 28 29 // Backend interface. 30 virtual int32 GetEntryCount() const; 31 virtual bool OpenEntry(const std::string& key, Entry** entry); 32 virtual int OpenEntry(const std::string& key, Entry** entry, 33 CompletionCallback* callback); 34 virtual bool CreateEntry(const std::string& key, Entry** entry); 35 virtual int CreateEntry(const std::string& key, Entry** entry, 36 CompletionCallback* callback); 37 virtual bool DoomEntry(const std::string& key); 38 virtual int DoomEntry(const std::string& key, CompletionCallback* callback); 39 virtual bool DoomAllEntries(); 40 virtual int DoomAllEntries(CompletionCallback* callback); 41 virtual bool DoomEntriesBetween(const base::Time initial_time, 42 const base::Time end_time); 43 virtual int DoomEntriesBetween(const base::Time initial_time, 44 const base::Time end_time, 45 CompletionCallback* callback); 46 virtual bool DoomEntriesSince(const base::Time initial_time); 47 virtual int DoomEntriesSince(const base::Time initial_time, 48 CompletionCallback* callback); 49 virtual bool OpenNextEntry(void** iter, Entry** next_entry); 50 virtual int OpenNextEntry(void** iter, Entry** next_entry, 51 CompletionCallback* callback); 52 virtual void EndEnumeration(void** iter); 53 virtual void GetStats( 54 std::vector<std::pair<std::string, std::string> >* stats) {} 55 56 // Sets the maximum size for the total amount of data stored by this instance. 57 bool SetMaxSize(int max_bytes); 58 59 // Permanently deletes an entry. 60 void InternalDoomEntry(MemEntryImpl* entry); 61 62 // Updates the ranking information for an entry. 63 void UpdateRank(MemEntryImpl* node); 64 65 // A user data block is being created, extended or truncated. 66 void ModifyStorageSize(int32 old_size, int32 new_size); 67 68 // Returns the maximum size for a file to reside on the cache. 69 int MaxFileSize() const; 70 71 // Insert an MemEntryImpl into the ranking list. This method is only called 72 // from MemEntryImpl to insert child entries. The reference can be removed 73 // by calling RemoveFromRankingList(|entry|). 74 void InsertIntoRankingList(MemEntryImpl* entry); 75 76 // Remove |entry| from ranking list. This method is only called from 77 // MemEntryImpl to remove a child entry from the ranking list. 78 void RemoveFromRankingList(MemEntryImpl* entry); 79 80 private: 81 // Deletes entries from the cache until the current size is below the limit. 82 // If empty is true, the whole cache will be trimmed, regardless of being in 83 // use. 84 void TrimCache(bool empty); 85 86 // Handles the used storage count. 87 void AddStorageSize(int32 bytes); 88 void SubstractStorageSize(int32 bytes); 89 90 typedef base::hash_map<std::string, MemEntryImpl*> EntryMap; 91 92 EntryMap entries_; 93 MemRankings rankings_; // Rankings to be able to trim the cache. 94 int32 max_size_; // Maximum data size for this instance. 95 int32 current_size_; 96 97 DISALLOW_EVIL_CONSTRUCTORS(MemBackendImpl); 98 }; 99 100 } // namespace disk_cache 101 102 #endif // NET_DISK_CACHE_MEM_BACKEND_IMPL_H__ 103
