private int readWriteBatch(int bucket, SliceInput record, int updateSize, Entrys entries)
throws IOException {
List<Entry<Slice, Slice>> list = Lists.newArrayListWithCapacity(updateSize);
int count = 0;
while (record.isReadable()) {
count++;
ValueType valueType = ValueType.getValueTypeByPersistentId(record.readByte());
if (valueType == VALUE) {
Slice key = readLengthPrefixedBytes(record);
Slice value = readLengthPrefixedBytes(record);
list.add(new BlockEntry(key, value));
} else if (valueType == DELETION) {
Slice key = readLengthPrefixedBytes(record);
list.add(new BlockEntry(key, Slices.EMPTY_SLICE));
} else {
throw new IllegalStateException("Unexpected value type " + valueType);
}
}
if (count != updateSize) {
throw new IOException(
String.format(
"Expected %d entries in log record but found %s entries", updateSize, entries));
}
int available = 0;
for (Entry<Slice, Slice> e : list) {
InternalKey iKey =
new InternalKey(e.getKey(), 0, e.getValue().length() != 0 ? VALUE : DELETION);
if (bucket == iKey.bucket()) {
entries.add(e);
available++;
}
}
return available;
}
// Writes a stream of chunks such that no chunk is split across a block boundary
@Override
public synchronized void addRecord(Slice record, boolean force) throws IOException {
Preconditions.checkState(!closed.get(), "Log has been closed");
SliceInput sliceInput = record.input();
// used to track first, middle and last blocks
boolean begin = true;
// Fragment the record int chunks as necessary and write it. Note that if record
// is empty, we still want to iterate once to write a single
// zero-length chunk.
do {
int bytesRemainingInBlock = BLOCK_SIZE - blockOffset;
Preconditions.checkState(bytesRemainingInBlock >= 0);
// Switch to a new block if necessary
if (bytesRemainingInBlock < HEADER_SIZE) {
if (bytesRemainingInBlock > 0) {
// Fill the rest of the block with zeros
// todo lame... need a better way to write zeros
fileChannel.write(ByteBuffer.allocate(bytesRemainingInBlock));
}
blockOffset = 0;
bytesRemainingInBlock = BLOCK_SIZE - blockOffset;
}
// Invariant: we never leave less than HEADER_SIZE bytes available in a block
int bytesAvailableInBlock = bytesRemainingInBlock - HEADER_SIZE;
Preconditions.checkState(bytesAvailableInBlock >= 0);
// if there are more bytes in the record then there are available in the block,
// fragment the record; otherwise write to the end of the record
boolean end;
int fragmentLength;
if (sliceInput.available() > bytesAvailableInBlock) {
end = false;
fragmentLength = bytesAvailableInBlock;
} else {
end = true;
fragmentLength = sliceInput.available();
}
// determine block type
LogChunkType type;
if (begin && end) {
type = LogChunkType.FULL;
} else if (begin) {
type = LogChunkType.FIRST;
} else if (end) {
type = LogChunkType.LAST;
} else {
type = LogChunkType.MIDDLE;
}
// write the chunk
writeChunk(type, sliceInput.readSlice(fragmentLength));
// we are no longer on the first chunk
begin = false;
} while (sliceInput.isReadable());
if (force) {
fileChannel.force(false);
}
}