1 /* 2 * A page mapper providing copied memory pages or deferring to another page 3 * mapper to satisfy file accesses. 4 * 5 * Copyright (C) 2021, 2022 Paul Boddie <paul@boddie.org.uk> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License as 9 * published by the Free Software Foundation; either version 2 of 10 * the License, or (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, 20 * Boston, MA 02110-1301, USA 21 */ 22 23 #pragma once 24 25 #include <list> 26 27 #include <fsserver/access_map.h> 28 #include <fsserver/generic_page_mapper.h> 29 #include <mem/memory_incremental.h> 30 31 32 33 /* A special flexpage class for copied flexpages. */ 34 35 class CopiedFlexpage : public Flexpage 36 { 37 public: 38 explicit CopiedFlexpage(Region *region = NULL); 39 }; 40 41 42 43 /* A file mapper, associating flexpages with file regions. */ 44 45 class CopiedPageMapper : public GenericPageMapper 46 { 47 protected: 48 GenericPageMapper *_mapper; 49 offset_t _size; 50 51 /* Copied page support. */ 52 53 AccessMap _map; 54 MemoryIncremental _memory; 55 std::list<Flexpage *> _queue; 56 57 /* Internal flexpage retrieval methods. */ 58 59 Flexpage *find(offset_t offset); 60 61 Flexpage *replicate_flexpage(offset_t offset, Flexpage *flexpage); 62 63 public: 64 explicit CopiedPageMapper(GenericPageMapper *mapper); 65 66 virtual ~CopiedPageMapper(); 67 68 /* Interface for the pager, implementing GenericPageMapper. */ 69 70 Flexpage *get(offset_t offset, map_flags_t flags); 71 72 void queue(Flexpage *flexpage); 73 74 void flush_all(offset_t start, offset_t size); 75 76 offset_t get_data_size(); 77 78 void set_data_size(offset_t size); 79 }; 80 81 // vim: tabstop=4 expandtab shiftwidth=4