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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_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 ~BackendImplV3() override; | |
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. | |
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 | |
118 net::CacheType cache_type() const { | |
119 return cache_type_; | |
120 } | |
121 | |
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 net::CacheType GetCacheType() const override; | |
176 int32 GetEntryCount() const override; | |
177 int OpenEntry(const std::string& key, | |
178 Entry** entry, | |
179 const CompletionCallback& callback) override; | |
180 int CreateEntry(const std::string& key, | |
181 Entry** entry, | |
182 const CompletionCallback& callback) override; | |
183 int DoomEntry(const std::string& key, | |
184 const CompletionCallback& callback) override; | |
185 int DoomAllEntries(const CompletionCallback& callback) override; | |
186 int DoomEntriesBetween(base::Time initial_time, | |
187 base::Time end_time, | |
188 const CompletionCallback& callback) override; | |
189 int DoomEntriesSince(base::Time initial_time, | |
190 const CompletionCallback& callback) override; | |
191 scoped_ptr<Iterator> CreateIterator() override; | |
192 void GetStats(StatsItems* stats) override; | |
193 void OnExternalCacheHit(const std::string& key) override; | |
194 | |
195 private: | |
196 friend class EvictionV3; | |
197 typedef base::hash_map<CacheAddr, EntryImplV3*> EntriesMap; | |
198 class IteratorImpl; | |
199 class NotImplementedIterator; | |
200 class Worker; | |
201 | |
202 void AdjustMaxCacheSize(); | |
203 bool InitStats(void* stats_data); | |
204 void StoreStats(); | |
205 | |
206 // Deletes the cache and starts again. | |
207 void RestartCache(bool failure); | |
208 void PrepareForRestart(); | |
209 | |
210 // Performs final cleanup. | |
211 void CleanupCache(); | |
212 | |
213 // Creates a new entry object. Returns zero on success, or a disk_cache error | |
214 // on failure. | |
215 int NewEntry(Addr address, EntryImplV3** entry); | |
216 | |
217 // Handles the used storage count. | |
218 void AddStorageSize(int32 bytes); | |
219 void SubstractStorageSize(int32 bytes); | |
220 | |
221 // Update the number of referenced cache entries. | |
222 void IncreaseNumRefs(); | |
223 void DecreaseNumRefs(); | |
224 void IncreaseNumEntries(); | |
225 void DecreaseNumEntries(); | |
226 | |
227 // Dumps current cache statistics to the log. | |
228 void LogStats(); | |
229 | |
230 // Send UMA stats. | |
231 void ReportStats(); | |
232 | |
233 // Reports an uncommon, recoverable error. | |
234 void ReportError(int error); | |
235 | |
236 // Performs basic checks on the index file. Returns false on failure. | |
237 bool CheckIndex(); | |
238 | |
239 // Part of the self test. Returns the number or dirty entries, or an error. | |
240 int CheckAllEntries(); | |
241 | |
242 // Part of the self test. Returns false if the entry is corrupt. | |
243 bool CheckEntry(EntryImplV3* cache_entry); | |
244 | |
245 // Returns the maximum total memory for the memory buffers. | |
246 int MaxBuffersSize(); | |
247 | |
248 IndexTable index_; | |
249 base::FilePath path_; // Path to the folder used as backing storage. | |
250 BlockBitmaps block_files_; | |
251 int32 max_size_; // Maximum data size for this instance. | |
252 EvictionV3 eviction_; // Handler of the eviction algorithm. | |
253 EntriesMap open_entries_; | |
254 int num_refs_; // Number of referenced cache entries. | |
255 int max_refs_; // Max number of referenced cache entries. | |
256 int entry_count_; // Number of entries accessed lately. | |
257 int byte_count_; // Number of bytes read/written lately. | |
258 int buffer_bytes_; // Total size of the temporary entries' buffers. | |
259 int up_ticks_; // The number of timer ticks received (OnTimerTick). | |
260 net::CacheType cache_type_; | |
261 int uma_report_; // Controls transmission of UMA data. | |
262 uint32 user_flags_; // Flags set by the user. | |
263 bool init_; // controls the initialization of the system. | |
264 bool restarted_; | |
265 bool read_only_; // Prevents updates of the rankings data (used by tools). | |
266 bool disabled_; | |
267 bool lru_eviction_; // What eviction algorithm should be used. | |
268 bool first_timer_; // True if the timer has not been called. | |
269 bool user_load_; // True if we see a high load coming from the caller. | |
270 | |
271 net::NetLog* net_log_; | |
272 | |
273 Stats stats_; // Usage statistics. | |
274 scoped_ptr<base::RepeatingTimer<BackendImplV3> > timer_; // Usage timer. | |
275 scoped_refptr<TraceObject> trace_object_; // Initializes internal tracing. | |
276 base::WeakPtrFactory<BackendImplV3> ptr_factory_; | |
277 | |
278 DISALLOW_COPY_AND_ASSIGN(BackendImplV3); | |
279 }; | |
280 | |
281 } // namespace disk_cache | |
282 | |
283 #endif // NET_DISK_CACHE_BLOCKFILE_BACKEND_IMPL_V3_H_ | |
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