private IRecord GetRecord(long recordId)
{
var record = new Record(recordId);
try
{
var currentBlockId = record.Id;
do
{
var block = _blockStorage.Find(currentBlockId);
if (block == null)
{
if (currentBlockId == RecordZero)
{
block = _blockStorage.Create();
return(RecordZero.WithBlocks(new[] { block }));
}
else
{
throw new Exception("Block not found by id: " + currentBlockId);
}
}
if (block.IsDeleted)
{
throw new InvalidDataException("Block not found: " + currentBlockId);
}
record.Blocks.Add(block);
currentBlockId = block.GetHeaderValue(BlockHeader.NextBlock);
} while (currentBlockId != 0);
}
catch (Exception)
{
record.Dispose();
throw;
}
return(record);
}
/// <summary>
/// Deletes the record of specified id.
/// </summary>
public void Delete(uint recordId)
{
using (IBlock block = blockStorage.Find(recordId)) {
IBlock curBlock = block;
while (true)
{
IBlock nextBlock = null;
using (curBlock) {
// Instead of actually "deleting" the block, we simply flag it deleted for reuse.
uint nextId = 0;
MarkAsReusable(curBlock, out nextId);
curBlock.SetHeader(BlockFields.IsDeleted, 1L);
// If curBlock doesn't have a reference to the next block, just break out
if (nextId == 0)
{
break;
}
// If there is a next block's id
else
{
nextBlock = blockStorage.Find(nextId);
if (nextBlock == null)
{
throw new InvalidDataException("Block not found with id: " + nextId);
}
}
}
// Move to next block
if (nextBlock != null)
{
curBlock = nextBlock;
}
}
}
}
//
// Public Methods
//
public virtual byte[] Find(uint recordId)
{
// First grab the block
using (var block = storage.Find(recordId))
{
if (block == null)
{
return(null);
}
// If this is a deleted block then ignore it
if (1L == block.GetHeader(kIsDeleted))
{
return(null);
}
// If this block is a child block then also ignore it
if (0L != block.GetHeader(kPreviousBlockId))
{
return(null);
}
// Grab total record size and allocate coressponded memory
var totalRecordSize = block.GetHeader(kRecordLength);
if (totalRecordSize > MaxRecordSize)
{
throw new NotSupportedException("Unexpected record length: " + totalRecordSize);
}
var data = new byte[totalRecordSize];
var bytesRead = 0;
// Now start filling data
IBlock currentBlock = block;
while (true)
{
uint nextBlockId;
using (currentBlock)
{
var thisBlockContentLength = currentBlock.GetHeader(kBlockContentLength);
if (thisBlockContentLength > storage.BlockContentSize)
{
throw new InvalidDataException("Unexpected block content length: " + thisBlockContentLength);
}
// Read all available content of current block
currentBlock.Read(dst: data, dstOffset: bytesRead, srcOffset: 0, count: (int)thisBlockContentLength);
// Update number of bytes read
bytesRead += (int)thisBlockContentLength;
// Move to the next block if there is any
nextBlockId = (uint)currentBlock.GetHeader(kNextBlockId);
if (nextBlockId == 0)
{
return(data);
}
} // Using currentBlock
currentBlock = this.storage.Find(nextBlockId);
if (currentBlock == null)
{
throw new InvalidDataException("Block not found by id: " + nextBlockId);
}
}
}
}