/// <summary>
/// Update document using same page position as reference
/// </summary>
public void Update(CollectionPage col, PageAddress blockAddress, BsonDocument doc)
{
var bytesLeft = doc.GetBytesCount(true);
if (bytesLeft > MAX_DOCUMENT_SIZE)
{
throw new LiteException(0, "Document size exceed {0} limit", MAX_DOCUMENT_SIZE);
}
DataBlock lastBlock = null;
var updateAddress = blockAddress;
IEnumerable <BufferSlice> source()
{
var bytesToCopy = 0;
while (bytesLeft > 0)
{
// if last block contains new block sequence, continue updating
if (updateAddress.IsEmpty == false)
{
var dataPage = _snapshot.GetPage <DataPage>(updateAddress.PageID);
var currentBlock = dataPage.GetBlock(updateAddress.Index);
// try get full page size content
bytesToCopy = Math.Min(bytesLeft, dataPage.FreeBytes + currentBlock.Buffer.Count);
// get current free slot linked list
var slot = BasePage.FreeIndexSlot(dataPage.FreeBytes);
var updateBlock = dataPage.UpdateBlock(currentBlock, bytesToCopy);
_snapshot.AddOrRemoveFreeList(dataPage, slot);
yield return(updateBlock.Buffer);
lastBlock = updateBlock;
// go to next address (if extits)
updateAddress = updateBlock.NextBlock;
}
else
{
bytesToCopy = Math.Min(bytesLeft, MAX_DATA_BYTES_PER_PAGE);
var dataPage = _snapshot.GetFreePage <DataPage>(bytesToCopy + DataBlock.DATA_BLOCK_FIXED_SIZE);
var insertBlock = dataPage.InsertBlock(bytesToCopy, true);
if (lastBlock != null)
{
lastBlock.SetNextBlock(insertBlock.Position);
}
yield return(insertBlock.Buffer);
lastBlock = insertBlock;
}
bytesLeft -= bytesToCopy;
}
// old document was bigger than current, must delete extend blocks
if (lastBlock.NextBlock.IsEmpty == false)
{
this.Delete(lastBlock.NextBlock);
}
}
// consume all source bytes to write BsonDocument direct into PageBuffer
// must be fastest as possible
using (var w = new BufferWriter(source()))
{
// already bytes count calculate at method start
w.WriteDocument(doc, false);
w.Consume();
}
}
