janwas
9269be9ee3
(see http://www.wildfiregames.com/forum/index.php?showtopic=11450&hl= ) clean up debug module . no longer include platform-dependent header (-> less rebuilds) . DISPLAY_ERROR -> DEBUG_DISPLAY_ERROR . parts of config.h that don't affect all files moved to config.2 (-> fewer full rebuilds) . remove creaky symbol cache (no longer needed for mmgr) . remove TLS thread naming stuff (can use debugger's thread window instead; no need for platform independence there) wdbg: remove thread suspension and breakpoint APIs (not needed) acpi: fix: u64 -> uintptr_t wutil: fix WinScopedLock, use that instead of direct lock() functions misc: . get rid of SAFE_STRCPY, replace with strcpy_s . remove _getcwd (shouldn't be used) This was SVN commit r5563.
90 lines
2.4 KiB
C++
90 lines
2.4 KiB
C++
/**
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* =========================================================================
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* File : block_cache.h
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* Project : 0 A.D.
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* Description : cache for aligned I/O blocks.
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* =========================================================================
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*/
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// license: GPL; see lib/license.txt
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#ifndef INCLUDED_BLOCK_CACHE
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#define INCLUDED_BLOCK_CACHE
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#include "lib/file/path.h"
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/**
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* ID that uniquely identifies a block within a file
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**/
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class BlockId
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{
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public:
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BlockId();
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BlockId(const Path& pathname, off_t ofs);
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bool operator==(const BlockId& rhs) const;
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bool operator!=(const BlockId& rhs) const;
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private:
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u64 m_id;
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};
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/**
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* cache of (aligned) file blocks with support for zero-copy IO.
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* absorbs the overhead of rounding up archive IOs to the nearest block
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* boundaries by keeping the last few blocks in memory.
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*
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* the interface is somewhat similar to FileCache; see the note there.
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*
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* not thread-safe (each thread is intended to have its own cache).
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**/
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class BlockCache
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{
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public:
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/**
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* @param numBlocks (the default value is enough to support temp buffers
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* and absorb the cost of unaligned reads from archives.)
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**/
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BlockCache(size_t numBlocks = 16);
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/**
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* Add a block to the cache.
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*
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* @param id key that will be used to Retrieve the block.
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*
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* call this when the block's IO has completed; its data will
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* satisfy subsequent Retrieve calls for the same id.
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* if CONFIG2_CACHE_READ_ONLY, the memory is made read-only.
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**/
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void Add(BlockId id, shared_ptr<u8> buf);
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/**
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* Attempt to retrieve a block's contents.
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*
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* @return whether the block is in cache.
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*
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* if successful, a shared pointer to the contents is returned.
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* they remain valid until all references are removed and the block
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* is evicted.
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**/
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bool Retrieve(BlockId id, shared_ptr<u8>& buf);
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/**
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* Invalidate the contents of the cache.
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*
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* this effectively discards the contents of existing blocks
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* (more specifically: prevents them from satisfying Retrieve calls
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* until a subsequent Add with the same id).
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*
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* useful for self-tests: multiple independent IO tests run in the same
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* process and must not influence each other via the cache.
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**/
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void InvalidateAll();
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private:
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class Impl;
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shared_ptr<Impl> impl;
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};
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#endif // #ifndef INCLUDED_BLOCK_CACHE
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