* Copyright 2017, ChαΊΏ VΕ© Gia Hy, cvghy116@gmail.com.
* Copyright 2001-2008, Axel DΓΆrfler, axeld@pinc-software.de.
* This file may be used under the terms of the MIT License.
*/
#ifndef CACHED_BLOCK_H
#define CACHED_BLOCK_H
#include "Volume.h"
#ifdef TRACE_BTRFS
# define TRACE(x...) dprintf("\33[34mbtrfs:\33[0m " x)
#else
# define TRACE(x...) ;
#endif
class CachedBlock {
public:
CachedBlock(Volume* volume);
CachedBlock(Volume* volume, off_t block);
~CachedBlock();
void Keep();
void Unset();
const uint8* SetTo(off_t block);
uint8* SetToWritable(off_t block, int32 transactionId,
bool empty);
const uint8* Block() const { return fBlock; }
off_t BlockNumber() const { return fBlockNumber; }
bool IsWritable() const { return fWritable; }
private:
CachedBlock(const CachedBlock&);
CachedBlock& operator=(const CachedBlock&);
protected:
Volume* fVolume;
off_t fBlockNumber;
uint8* fBlock;
bool fWritable;
};
inline
CachedBlock::CachedBlock(Volume* volume)
:
fVolume(volume),
fBlockNumber(0),
fBlock(NULL),
fWritable(false)
{
}
inline
CachedBlock::CachedBlock(Volume* volume, off_t block)
:
fVolume(volume),
fBlockNumber(0),
fBlock(NULL),
fWritable(false)
{
SetTo(block);
}
inline
CachedBlock::~CachedBlock()
{
Unset();
}
inline void
CachedBlock::Keep()
{
fBlock = NULL;
}
inline void
CachedBlock::Unset()
{
if (fBlock != NULL) {
block_cache_put(fVolume->BlockCache(), fBlockNumber);
fBlock = NULL;
}
}
inline const uint8*
CachedBlock::SetTo(off_t block)
{
Unset();
fBlockNumber = block;
return fBlock = (uint8*)block_cache_get(fVolume->BlockCache(), block);
}
inline uint8*
CachedBlock::SetToWritable(off_t block, int32 transactionId, bool empty)
{
Unset();
fBlockNumber = block;
fWritable = true;
if (empty) {
fBlock = (uint8*)block_cache_get_empty(fVolume->BlockCache(),
block, transactionId);
} else {
fBlock = (uint8*)block_cache_get_writable(fVolume->BlockCache(),
block, transactionId);
}
return fBlock;
}
#endif
