/// <summary>
/// Async constructor
/// </summary>
public static async Task <BufferWriterAsync> CreateAsync(IAsyncEnumerable <BufferSlice> source)
{
var writer = new BufferWriterAsync(source);
await writer.InitializeAsync();
return(writer);
}
/// <summary>
/// Insert BsonDocument into new data pages
/// </summary>
public async Task <PageAddress> Insert(BsonDocument doc)
{
var bytesLeft = doc.GetBytesCount(true);
if (bytesLeft > MAX_DOCUMENT_SIZE)
{
throw new LiteException(0, "Document size exceed {0} limit", MAX_DOCUMENT_SIZE);
}
var firstBlock = PageAddress.Empty;
async IAsyncEnumerable <BufferSlice> source()
{
var blockIndex = 0;
DataBlock lastBlock = null;
while (bytesLeft > 0)
{
var bytesToCopy = Math.Min(bytesLeft, MAX_DATA_BYTES_PER_PAGE);
var dataPage = await _snapshot.GetFreeDataPage(bytesToCopy + DataBlock.DATA_BLOCK_FIXED_SIZE);
var dataBlock = dataPage.InsertBlock(bytesToCopy, blockIndex++ > 0);
if (lastBlock != null)
{
lastBlock.SetNextBlock(dataBlock.Position);
}
if (firstBlock.IsEmpty)
{
firstBlock = dataBlock.Position;
}
await _snapshot.AddOrRemoveFreeDataList(dataPage);
yield return(dataBlock.Buffer);
lastBlock = dataBlock;
bytesLeft -= bytesToCopy;
}
}
// consume all source bytes to write BsonDocument direct into PageBuffer
// must be fastest as possible
await using (var writer = await BufferWriterAsync.CreateAsync(source()))
{
// already bytes count calculate at method start
await writer.WriteDocument(doc, false);
await writer.Consume();
}
return(firstBlock);
}
/// <summary>
/// Update document using same page position as reference
/// </summary>
public async Task 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;
async IAsyncEnumerable <BufferSlice> source()
{
var bytesToCopy = 0;
while (bytesLeft > 0)
{
// if last block contains new block sequence, continue updating
if (updateAddress.IsEmpty == false)
{
var dataPage = await _snapshot.GetPage <DataPage>(updateAddress.PageID);
var currentBlock = dataPage.GetBlock(updateAddress.Index);
// try get full page size content (do not add DATA_BLOCK_FIXED_SIZE because will be added in UpdateBlock)
bytesToCopy = Math.Min(bytesLeft, dataPage.FreeBytes + currentBlock.Buffer.Count);
var updateBlock = dataPage.UpdateBlock(currentBlock, bytesToCopy);
await _snapshot.AddOrRemoveFreeDataList(dataPage);
yield return(updateBlock.Buffer);
lastBlock = updateBlock;
// go to next address (if exists)
updateAddress = updateBlock.NextBlock;
}
else
{
bytesToCopy = Math.Min(bytesLeft, MAX_DATA_BYTES_PER_PAGE);
var dataPage = await _snapshot.GetFreeDataPage(bytesToCopy + DataBlock.DATA_BLOCK_FIXED_SIZE);
var insertBlock = dataPage.InsertBlock(bytesToCopy, true);
if (lastBlock != null)
{
lastBlock.SetNextBlock(insertBlock.Position);
}
await _snapshot.AddOrRemoveFreeDataList(dataPage);
yield return(insertBlock.Buffer);
lastBlock = insertBlock;
}
bytesLeft -= bytesToCopy;
}
// old document was bigger than current, must delete extend blocks
if (lastBlock.NextBlock.IsEmpty == false)
{
var nextBlockAddress = lastBlock.NextBlock;
lastBlock.SetNextBlock(PageAddress.Empty);
await this.Delete(nextBlockAddress);
}
}
// consume all source bytes to write BsonDocument direct into PageBuffer
await using (var writer = await BufferWriterAsync.CreateAsync(source()))
{
// already bytes count calculate at method start
await writer.WriteDocument(doc, false);
await writer.Consume();
}
}
