1 /* <!-- copyright */ 2 /* 3 * aria2 - The high speed download utility 4 * 5 * Copyright (C) 2012 Tatsuhiro Tsujikawa 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 20 * 21 * In addition, as a special exception, the copyright holders give 22 * permission to link the code of portions of this program with the 23 * OpenSSL library under certain conditions as described in each 24 * individual source file, and distribute linked combinations 25 * including the two. 26 * You must obey the GNU General Public License in all respects 27 * for all of the code used other than OpenSSL. If you modify 28 * file(s) with this exception, you may extend this exception to your 29 * version of the file(s), but you are not obligated to do so. If you 30 * do not wish to do so, delete this exception statement from your 31 * version. If you delete this exception statement from all source 32 * files in the program, then also delete it here. 33 */ 34 /* copyright --> */ 35 #ifndef D_WR_DISK_CACHE_H 36 #define D_WR_DISK_CACHE_H 37 38 #include "common.h" 39 40 #include <set> 41 42 #include "a2functional.h" 43 44 namespace aria2 { 45 46 class WrDiskCacheEntry; 47 48 class WrDiskCache { 49 public: 50 WrDiskCache(size_t limit); 51 ~WrDiskCache(); 52 // Adds the cache entry |ent| to the storage. The size of cached 53 // data of ent is added to total_. 54 bool add(WrDiskCacheEntry* ent); 55 // Removes the cache entry |ent| from the stroage. The size of 56 // cached data of ent is subtracted from total_. 57 bool remove(WrDiskCacheEntry* ent); 58 // Updates the already added entry |ent|. The |delta| means how many 59 // bytes is increased in this update. If the size is reduced, use 60 // negative value. 61 bool update(WrDiskCacheEntry* ent, ssize_t delta); 62 // Evicts entries from storage so that total size of cache is kept 63 // under the limit. 64 void ensureLimit(); getSize()65 size_t getSize() const { return total_; } 66 67 private: 68 typedef std::set<WrDiskCacheEntry*, DerefLess<WrDiskCacheEntry*>> EntrySet; 69 // Maximum number of bytes the storage can cache. 70 size_t limit_; 71 // Current number of bytes cached. 72 size_t total_; 73 EntrySet set_; 74 int64_t clock_; 75 }; 76 77 } // namespace aria2 78 79 #endif // D_WR_DISK_CACHE_H 80