1 // Copyright (c) 2011 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 #ifndef NET_DISK_CACHE_EVICTION_H_ 6 #define NET_DISK_CACHE_EVICTION_H_ 7 #pragma once 8 9 #include "base/basictypes.h" 10 #include "base/task.h" 11 #include "net/disk_cache/disk_format.h" 12 #include "net/disk_cache/rankings.h" 13 14 namespace disk_cache { 15 16 class BackendImpl; 17 class EntryImpl; 18 19 // This class implements the eviction algorithm for the cache and it is tightly 20 // integrated with BackendImpl. 21 class Eviction { 22 public: 23 Eviction(); 24 ~Eviction(); 25 26 void Init(BackendImpl* backend); 27 void Stop(); 28 29 // Deletes entries from the cache until the current size is below the limit. 30 // If empty is true, the whole cache will be trimmed, regardless of being in 31 // use. 32 void TrimCache(bool empty); 33 34 // Updates the ranking information for an entry. 35 void UpdateRank(EntryImpl* entry, bool modified); 36 37 // Notifications of interesting events for a given entry. 38 void OnOpenEntry(EntryImpl* entry); 39 void OnCreateEntry(EntryImpl* entry); 40 void OnDoomEntry(EntryImpl* entry); 41 void OnDestroyEntry(EntryImpl* entry); 42 43 // Testing interface. 44 void SetTestMode(); 45 void TrimDeletedList(bool empty); 46 47 private: 48 void PostDelayedTrim(); 49 void DelayedTrim(); 50 bool ShouldTrim(); 51 void ReportTrimTimes(EntryImpl* entry); 52 Rankings::List GetListForEntry(EntryImpl* entry); 53 bool EvictEntry(CacheRankingsBlock* node, bool empty, Rankings::List list); 54 55 // We'll just keep for a while a separate set of methods that implement the 56 // new eviction algorithm. This code will replace the original methods when 57 // finished. 58 void TrimCacheV2(bool empty); 59 void UpdateRankV2(EntryImpl* entry, bool modified); 60 void OnOpenEntryV2(EntryImpl* entry); 61 void OnCreateEntryV2(EntryImpl* entry); 62 void OnDoomEntryV2(EntryImpl* entry); 63 void OnDestroyEntryV2(EntryImpl* entry); 64 Rankings::List GetListForEntryV2(EntryImpl* entry); 65 void TrimDeleted(bool empty); 66 bool RemoveDeletedNode(CacheRankingsBlock* node); 67 68 bool NodeIsOldEnough(CacheRankingsBlock* node, int list); 69 int SelectListByLength(Rankings::ScopedRankingsBlock* next); 70 void ReportListStats(); 71 72 BackendImpl* backend_; 73 Rankings* rankings_; 74 IndexHeader* header_; 75 int max_size_; 76 int trim_delays_; 77 bool new_eviction_; 78 bool first_trim_; 79 bool trimming_; 80 bool delay_trim_; 81 bool init_; 82 bool test_mode_; 83 bool in_experiment_; 84 ScopedRunnableMethodFactory<Eviction> factory_; 85 86 DISALLOW_COPY_AND_ASSIGN(Eviction); 87 }; 88 89 } // namespace disk_cache 90 91 #endif // NET_DISK_CACHE_EVICTION_H_ 92