Initial checkin. Stolen from BFS and then touched up so no one will notice.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4152 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/file_systems/udf/CachedBlock.h

@@ -0,0 +1,152 @@
+//----------------------------------------------------------------------
+//  This software is part of the OpenBeOS distribution and is covered 
+//  by the OpenBeOS license.
+//
+//  Copyright (c) 2003 Tyler Dauwalder, [email protected]
+//  Based on the CachedBlock class from OpenBFS,
+//  Copyright (c) 2002 Axel Dörfler, [email protected]
+//---------------------------------------------------------------------
+#ifndef _UDF_CACHED_BLOCK_H
+#define _UDF_CACHED_BLOCK_H
+
+/*! \file CachedBlock.h
+
+	Based on the CachedBlock class from OpenBFS, written by
+	Axel Dörfler, [email protected]
+*/
+
+extern "C" {
+	#ifndef _IMPEXP_KERNEL
+	#	define _IMPEXP_KERNEL
+	#endif
+	
+	#include <fsproto.h>
+	#include "lock.h"
+	#include "cache.h"
+}
+
+#include "cpp.h"
+#include "UdfDebug.h"
+
+#include "DiskStructures.h"
+#include "Volume.h"
+
+namespace Udf {
+
+class CachedBlock {
+	public:
+		CachedBlock(Volume *volume);
+		CachedBlock(Volume *volume, off_t block, bool empty = false);
+		CachedBlock(CachedBlock *cached);
+		~CachedBlock();
+
+		inline void Keep();
+		inline void Unset();
+		inline uint8 *SetTo(off_t block, bool empty = false);
+		inline uint8 *SetTo(udf_long_address address, bool empty = false);
+		template <class Accessor, class Descriptor>
+			inline uint8* SetTo(Accessor &accessor, Descriptor &descriptor,
+			bool empty = false);
+
+		uint8 *Block() const { return fBlock; }
+		off_t BlockNumber() const { return fBlockNumber; }
+		uint32 BlockSize() const { return fVolume->BlockSize(); }
+		uint32 BlockShift() const { return fVolume->BlockShift(); }
+
+	private:
+		CachedBlock(const CachedBlock &);				// unimplemented
+		CachedBlock &operator=(const CachedBlock &);	// unimplemented
+
+	protected:
+		Volume	*fVolume;
+		off_t	fBlockNumber;
+		uint8	*fBlock;
+};
+
+inline
+CachedBlock::CachedBlock(Volume *volume)
+	:
+	fVolume(volume),
+	fBlock(NULL)
+{
+}
+
+inline
+CachedBlock::CachedBlock(Volume *volume, off_t block, bool empty = false)
+	:
+	fVolume(volume),
+	fBlock(NULL)
+{
+	SetTo(block, empty);
+}
+
+inline 
+CachedBlock::CachedBlock(CachedBlock *cached)
+	: fVolume(cached->fVolume)
+	, fBlockNumber(cached->BlockNumber())
+	, fBlock(cached->fBlock)
+{
+	cached->Keep();
+}
+
+inline
+CachedBlock::~CachedBlock()
+{
+	Unset();
+}
+
+inline void
+CachedBlock::Keep()
+{
+	fBlock = NULL;
+}
+
+inline void
+CachedBlock::Unset()
+{
+	DEBUG_INIT(CF_HIGH_VOLUME | CF_PUBLIC, "CachedBlock");
+	if (fBlock) {
+		PRINT(("releasing block #%lld\n", BlockNumber()));	
+		release_block(fVolume->Device(), fBlockNumber);
+	} else {
+		PRINT(("no block to release\n"));
+	}
+}
+
+inline uint8 *
+CachedBlock::SetTo(off_t block, bool empty = false)
+{
+	DEBUG_INIT_ETC(CF_HIGH_VOLUME | CF_PUBLIC, "CachedBlock", ("block: %lld, empty: %s",
+	               block, (empty ? "true" : "false")));
+	Unset();
+	fBlockNumber = block;
+	PRINT(("getting block #%lld\n", block));
+	return fBlock = empty ? (uint8 *)get_empty_block(fVolume->Device(), block, BlockSize())
+						  : (uint8 *)get_block(fVolume->Device(), block, BlockSize());
+}
+
+inline uint8 *
+CachedBlock::SetTo(udf_long_address address, bool empty = false)
+{
+	off_t block;
+	if (fVolume->MapBlock(address, &block) == B_OK)
+		return SetTo(block, empty);
+	else
+		return NULL;
+}
+
+template <class Accessor, class Descriptor>
+inline uint8*
+CachedBlock::SetTo(Accessor &accessor, Descriptor &descriptor, bool empty = false)
+{
+	// Make a udf_long_address out of the descriptor and call it a day
+	udf_long_address address;
+	address.set_to(accessor.GetBlock(descriptor),
+                             accessor.GetPartition(descriptor));
+    return SetTo(address, empty);
+}
+
+};	// namespace Udf
+
+#endif	// _UDF_CACHED_BLOCK_H
+