internal ReadOnlySpan <byte> EncodeBatch(KeyValuePair <byte[], ResultCacheEntry>[] operations)
{
if (operations.Length == 0)
{
throw new ArgumentException("Zero size batch", nameof(operations));
}
long maxSize = 0;
maxSize += 8; // sequence
maxSize += 4 * operations.Length; // count
foreach (KeyValuePair <byte[], ResultCacheEntry> entry in operations)
{
maxSize += 1; // op code
maxSize += 10; // varint max
maxSize += entry.Key.Length;
if (entry.Value.ResultState == ResultState.Exist)
{
maxSize += 10; // varint max
maxSize += entry.Value.Data?.Length ?? 0;
}
}
Span <byte> data = new byte[maxSize]; // big enough to contain all data regardless of size
var writer = new SpanWriter(data);
// write sequence
writer.Write((ulong)operations.First().Value.Sequence);
// write operations count
writer.Write((uint)operations.Length);
foreach (KeyValuePair <byte[], ResultCacheEntry> operation in operations)
{
byte[] key = operation.Key;
ResultCacheEntry entry = operation.Value;
// write op type (byte)
writer.Write(entry.ResultState == ResultState.Exist ? (byte)OperationType.Value : (byte)OperationType.Delete);
// write key
writer.WriteLengthPrefixed(key);
if (entry.ResultState == ResultState.Exist)
{
// write data
writer.WriteLengthPrefixed(entry.Data);
}
}
return(data.Slice(0, writer.Position));
}
internal void Put(WriteBatch batch)
{
if (_resultCache == null)
{
throw new InvalidOperationException("Log not prepared for updates. Did you forget to call Open()?");
}
foreach (BatchOperation operation in batch.Operations)
{
byte[] key = operation.Key;
byte[] data = operation.Data;
_estimatedSize += (ulong)(key.Length + 8 + data.Length + 10 /* varlong * 2 */);
_resultCache[key] = new ResultCacheEntry
{
Sequence = (long)batch.Sequence,
Data = data,
ResultState = ResultState.Exist
};
}
}
