152 lines
3.8 KiB
C++
152 lines
3.8 KiB
C++
/*
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* Copyright (c) 2013, 2014, 2017 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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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 <sys/types.h>
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#include <stddef.h>
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#include <stdint.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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struct iovec;
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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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uint8_t* BlockDataUnlocked(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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size_t unused_block_count;
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size_t blocks_used;
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size_t blocks_allocated;
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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 preadv(ioctx_t* ctx, const struct iovec* iov, int iovcnt,
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off_t off);
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ssize_t pwritev(ioctx_t* ctx, const struct iovec* iov, int iovcnt,
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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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