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_BACKEND_IMPL_V3_H_ 8 #define NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_V3_H_ 9 10 #include "base/containers/hash_tables.h" 11 #include "base/files/file_path.h" 12 #include "base/memory/ref_counted.h" 13 #include "base/timer/timer.h" 14 #include "net/disk_cache/blockfile/block_bitmaps_v3.h" 15 #include "net/disk_cache/blockfile/block_files.h" 16 #include "net/disk_cache/blockfile/eviction_v3.h" 17 #include "net/disk_cache/blockfile/index_table_v3.h" 18 #include "net/disk_cache/blockfile/stats.h" 19 #include "net/disk_cache/blockfile/stress_support.h" 20 #include "net/disk_cache/blockfile/trace.h" 21 #include "net/disk_cache/disk_cache.h" 22 23 namespace base { 24 class SingleThreadTaskRunner; 25 } // namespace base 26 27 namespace net { 28 class NetLog; 29 } // namespace net 30 31 namespace disk_cache { 32 33 class EntryImplV3; 34 35 // This class implements the Backend interface. An object of this 36 // class handles the operations of the cache for a particular profile. 37 class NET_EXPORT_PRIVATE BackendImplV3 : public Backend { 38 public: 39 enum BackendFlags { 40 MAX_SIZE = 1 << 1, // A maximum size was provided. 41 UNIT_TEST_MODE = 1 << 2, // We are modifying the behavior for testing. 42 UPGRADE_MODE = 1 << 3, // This is the upgrade tool (dump). 43 EVICTION_V2 = 1 << 4, // Use of new eviction was specified. 44 BASIC_UNIT_TEST = 1 << 5, // Identifies almost all unit tests. 45 NO_LOAD_PROTECTION = 1 << 6, // Don't act conservatively under load. 46 NO_BUFFERING = 1 << 7, // Disable extended IO buffering. 47 NO_CLEAN_ON_EXIT = 1 << 8 // Avoid saving data at exit time. 48 }; 49 50 BackendImplV3(const base::FilePath& path, 51 const scoped_refptr<base::SingleThreadTaskRunner>& cache_thread, 52 net::NetLog* net_log); 53 virtual ~BackendImplV3(); 54 55 // Performs general initialization for this current instance of the cache. 56 int Init(const CompletionCallback& callback); 57 58 // Sets the maximum size for the total amount of data stored by this instance. 59 bool SetMaxSize(int max_bytes); 60 61 // Sets the cache type for this backend. 62 void SetType(net::CacheType type); 63 64 // Creates a new storage block of size block_count. 65 bool CreateBlock(FileType block_type, int block_count, 66 Addr* block_address); 67 68 // Updates the ranking information for an entry. 69 void UpdateRank(EntryImplV3* entry, bool modified); 70 71 // Permanently deletes an entry, but still keeps track of it. 72 void InternalDoomEntry(EntryImplV3* entry); 73 74 // This method must be called when an entry is released for the last time, so 75 // the entry should not be used anymore. |address| is the cache address of the 76 // entry. 77 void OnEntryDestroyBegin(Addr address); 78 79 // This method must be called after all resources for an entry have been 80 // released. 81 void OnEntryDestroyEnd(); 82 83 // If the |address| corresponds to an open entry, returns a pointer to that 84 // entry, otherwise returns NULL. Note that this method does not increase the 85 // ref counter for the entry. 86 EntryImplV3* GetOpenEntry(Addr address) const; 87 88 // Returns the id being used on this run of the cache. 89 int32 GetCurrentEntryId() const; 90 91 // Returns the maximum size for a file to reside on the cache. 92 int MaxFileSize() const; 93 94 // A user data block is being created, extended or truncated. 95 void ModifyStorageSize(int32 old_size, int32 new_size); 96 97 // Logs requests that are denied due to being too big. 98 void TooMuchStorageRequested(int32 size); 99 100 // Returns true if a temporary buffer is allowed to be extended. 101 bool IsAllocAllowed(int current_size, int new_size); 102 103 // Tracks the release of |size| bytes by an entry buffer. 104 void BufferDeleted(int size); 105 106 // Only intended for testing the two previous methods. GetTotalBuffersSize()107 int GetTotalBuffersSize() const { 108 return buffer_bytes_; 109 } 110 111 // Returns true if this instance seems to be under heavy load. 112 bool IsLoaded() const; 113 114 // Returns the full histogram name, for the given base |name| and the current 115 // cache type. The name will be "DiskCache3.name_type". 116 std::string HistogramName(const char* name) const; 117 cache_type()118 net::CacheType cache_type() const { 119 return cache_type_; 120 } 121 read_only()122 bool read_only() const { 123 return read_only_; 124 } 125 126 // Returns a weak pointer to this object. 127 base::WeakPtr<BackendImplV3> GetWeakPtr(); 128 129 // Returns true if we should send histograms for this user again. The caller 130 // must call this function only once per run (because it returns always the 131 // same thing on a given run). 132 bool ShouldReportAgain(); 133 134 // Reports some data when we filled up the cache. 135 void FirstEviction(); 136 137 // Called when an interesting event should be logged (counted). 138 void OnEvent(Stats::Counters an_event); 139 140 // Keeps track of payload access (doesn't include metadata). 141 void OnRead(int bytes); 142 void OnWrite(int bytes); 143 144 // Timer callback to calculate usage statistics and perform backups. 145 void OnTimerTick(); 146 147 // Sets internal parameters to enable unit testing mode. 148 void SetUnitTestMode(); 149 150 // Sets internal parameters to enable upgrade mode (for internal tools). 151 void SetUpgradeMode(); 152 153 // Sets the eviction algorithm to version 2. 154 void SetNewEviction(); 155 156 // Sets an explicit set of BackendFlags. 157 void SetFlags(uint32 flags); 158 159 // Sends a dummy operation through the operation queue, for unit tests. 160 int FlushQueueForTest(const CompletionCallback& callback); 161 162 // Trims an entry (all if |empty| is true) from the list of deleted 163 // entries. This method should be called directly on the cache thread. 164 void TrimForTest(bool empty); 165 166 // Trims an entry (all if |empty| is true) from the list of deleted 167 // entries. This method should be called directly on the cache thread. 168 void TrimDeletedListForTest(bool empty); 169 170 // Performs a simple self-check, and returns the number of dirty items 171 // or an error code (negative value). 172 int SelfCheck(); 173 174 // Backend implementation. 175 virtual net::CacheType GetCacheType() const OVERRIDE; 176 virtual int32 GetEntryCount() const OVERRIDE; 177 virtual int OpenEntry(const std::string& key, Entry** entry, 178 const CompletionCallback& callback) OVERRIDE; 179 virtual int CreateEntry(const std::string& key, Entry** entry, 180 const CompletionCallback& callback) OVERRIDE; 181 virtual int DoomEntry(const std::string& key, 182 const CompletionCallback& callback) OVERRIDE; 183 virtual int DoomAllEntries(const CompletionCallback& callback) OVERRIDE; 184 virtual int DoomEntriesBetween(base::Time initial_time, 185 base::Time end_time, 186 const CompletionCallback& callback) OVERRIDE; 187 virtual int DoomEntriesSince(base::Time initial_time, 188 const CompletionCallback& callback) OVERRIDE; 189 virtual scoped_ptr<Iterator> CreateIterator() OVERRIDE; 190 virtual void GetStats(StatsItems* stats) OVERRIDE; 191 virtual void OnExternalCacheHit(const std::string& key) OVERRIDE; 192 193 private: 194 friend class EvictionV3; 195 typedef base::hash_map<CacheAddr, EntryImplV3*> EntriesMap; 196 class IteratorImpl; 197 class NotImplementedIterator; 198 class Worker; 199 200 void AdjustMaxCacheSize(); 201 bool InitStats(void* stats_data); 202 void StoreStats(); 203 204 // Deletes the cache and starts again. 205 void RestartCache(bool failure); 206 void PrepareForRestart(); 207 208 // Performs final cleanup. 209 void CleanupCache(); 210 211 // Creates a new entry object. Returns zero on success, or a disk_cache error 212 // on failure. 213 int NewEntry(Addr address, EntryImplV3** entry); 214 215 // Handles the used storage count. 216 void AddStorageSize(int32 bytes); 217 void SubstractStorageSize(int32 bytes); 218 219 // Update the number of referenced cache entries. 220 void IncreaseNumRefs(); 221 void DecreaseNumRefs(); 222 void IncreaseNumEntries(); 223 void DecreaseNumEntries(); 224 225 // Dumps current cache statistics to the log. 226 void LogStats(); 227 228 // Send UMA stats. 229 void ReportStats(); 230 231 // Reports an uncommon, recoverable error. 232 void ReportError(int error); 233 234 // Performs basic checks on the index file. Returns false on failure. 235 bool CheckIndex(); 236 237 // Part of the self test. Returns the number or dirty entries, or an error. 238 int CheckAllEntries(); 239 240 // Part of the self test. Returns false if the entry is corrupt. 241 bool CheckEntry(EntryImplV3* cache_entry); 242 243 // Returns the maximum total memory for the memory buffers. 244 int MaxBuffersSize(); 245 246 IndexTable index_; 247 base::FilePath path_; // Path to the folder used as backing storage. 248 BlockBitmaps block_files_; 249 int32 max_size_; // Maximum data size for this instance. 250 EvictionV3 eviction_; // Handler of the eviction algorithm. 251 EntriesMap open_entries_; 252 int num_refs_; // Number of referenced cache entries. 253 int max_refs_; // Max number of referenced cache entries. 254 int entry_count_; // Number of entries accessed lately. 255 int byte_count_; // Number of bytes read/written lately. 256 int buffer_bytes_; // Total size of the temporary entries' buffers. 257 int up_ticks_; // The number of timer ticks received (OnTimerTick). 258 net::CacheType cache_type_; 259 int uma_report_; // Controls transmission of UMA data. 260 uint32 user_flags_; // Flags set by the user. 261 bool init_; // controls the initialization of the system. 262 bool restarted_; 263 bool read_only_; // Prevents updates of the rankings data (used by tools). 264 bool disabled_; 265 bool lru_eviction_; // What eviction algorithm should be used. 266 bool first_timer_; // True if the timer has not been called. 267 bool user_load_; // True if we see a high load coming from the caller. 268 269 net::NetLog* net_log_; 270 271 Stats stats_; // Usage statistics. 272 scoped_ptr<base::RepeatingTimer<BackendImplV3> > timer_; // Usage timer. 273 scoped_refptr<TraceObject> trace_object_; // Initializes internal tracing. 274 base::WeakPtrFactory<BackendImplV3> ptr_factory_; 275 276 DISALLOW_COPY_AND_ASSIGN(BackendImplV3); 277 }; 278 279 } // namespace disk_cache 280 281 #endif // NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_V3_H_ 282