144 lines
3.6 KiB
C
144 lines
3.6 KiB
C
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/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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sortix/kernel/fcache.h
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Cache mechanism for file contents.
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*******************************************************************************/
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#ifndef INCLUDE_SORTIX_KERNEL_FCACHE_H
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#define INCLUDE_SORTIX_KERNEL_FCACHE_H
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#include <sortix/kernel/addralloc.h>
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#include <sortix/kernel/kthread.h>
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#include <sortix/kernel/memorymanagement.h>
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namespace Sortix {
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struct ioctx_struct;
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typedef struct ioctx_struct ioctx_t;
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class BlockCache;
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struct BlockCacheArea;
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struct BlockCacheBlock;
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class FileCache;
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//class FileCacheBackend;
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const uintptr_t BCACHE_PRESENT = 1 << 0;
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const uintptr_t BCACHE_USED = 1 << 1;
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const uintptr_t BCACHE_MODIFIED = 1 << 2;
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class BlockCache
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{
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public:
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BlockCache();
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~BlockCache();
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BlockCacheBlock* AcquireBlock();
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void ReleaseBlock(BlockCacheBlock* block);
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void MarkUsed(BlockCacheBlock* block);
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void MarkModified(BlockCacheBlock* block);
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uint8_t* BlockData(BlockCacheBlock* block);
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public:
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bool AddArea();
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void UnlinkBlock(BlockCacheBlock* block);
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void LinkBlock(BlockCacheBlock* block);
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private:
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BlockCacheArea* areas;
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size_t areas_used;
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size_t areas_length;
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size_t blocks_per_area;
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BlockCacheBlock* mru_block;
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BlockCacheBlock* lru_block;
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BlockCacheBlock* unused_block;
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kthread_mutex_t bcache_mutex;
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};
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struct BlockCacheArea
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{
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uint8_t* data;
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BlockCacheBlock* blocks;
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struct addralloc_t addralloc;
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};
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struct BlockCacheBlock
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{
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uintptr_t information;
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FileCache* fcache;
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BlockCacheBlock* next_block;
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BlockCacheBlock* prev_block;
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uintptr_t BlockId() { return information >> 12; }
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};
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class FileCache
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{
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public:
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static void Init();
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public:
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FileCache(/*FileCacheBackend* backend = NULL*/);
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~FileCache();
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int sync(ioctx_t* ctx);
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ssize_t pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t off);
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ssize_t pwrite(ioctx_t* ctx, const uint8_t* buf, size_t count, off_t off);
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int truncate(ioctx_t* ctx, off_t length);
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off_t lseek(ioctx_t* ctx, off_t offset, int whence);
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//bool ChangeBackend(FileCacheBackend* backend, bool sync_old);
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off_t GetFileSize();
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private:
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bool ChangeSize(off_t newsize, bool exact);
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bool ChangeNumBlocks(size_t numblocks, bool exact);
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bool Synchronize();
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void InitializeFileData(off_t to_where);
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private:
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off_t file_size;
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off_t file_written;
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BlockCacheBlock** blocks;
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size_t blocks_used;
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size_t blocks_length;
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kthread_mutex_t fcache_mutex;
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bool modified;
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bool modified_size;
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//FileCacheBackend* backend;
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};
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/*
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class FileCacheBackend
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{
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public:
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virtual ~FileCacheBackend() { }
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virtual int fcache_sync(ioctx_t* ctx) = 0;
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virtual ssize_t fcache_pread(ioctx_t* ctx, uint8_t* buf, size_t count, off_t off) = 0;
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virtual ssize_t fcache_pwrite(ioctx_t* ctx, const uint8_t* buf, size_t count, off_t off) = 0;
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virtual int fcache_truncate(ioctx_t* ctx, off_t length) = 0;
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virtual off_t fcache_lseek(ioctx_t* ctx, off_t offset, int whence) = 0;
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};
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*/
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} // namespace Sortix
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#endif
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