public ByteSource asByteSource(ReadOnlyTransaction txn) throws IOException {
ByteBuffer snapshotHeader = ByteBuffer.allocate(HEADER_SIZE);
{
ByteBuffer header = buildHeader();
assert header.remaining() == MASTERPAGE_HEADER_SIZE;
snapshotHeader.put(header);
}
// We build a master header with just the current snapshot transaction
for (int i = 0; i < MASTERPAGE_SLOTS; i++) {
int position = MASTERPAGE_HEADER_SIZE + (i * MASTERPAGE_SLOT_SIZE);
ByteBuffer mmap = ByteBuffer.allocate(MASTERPAGE_SLOT_SIZE);
assert mmap.position() == 0;
int rootPage = txn.rootPageId;
int transactionPage = txn.transactionPageId;
long transactionId = txn.snapshotTransactionId;
MasterPage.create(mmap, rootPage, transactionPage, transactionId);
mmap.position(MASTERPAGE_SLOT_SIZE);
mmap.flip();
assert mmap.remaining() == MASTERPAGE_SLOT_SIZE;
snapshotHeader.position(position);
snapshotHeader.put(mmap);
}
snapshotHeader.position(0);
ByteSource dataByteSource = asByteSource0();
dataByteSource = dataByteSource.slice(HEADER_SIZE, Long.MAX_VALUE);
return ByteSource.concat(new ByteBufferByteSource(snapshotHeader), dataByteSource);
}
protected Payload doSlice(ByteSource content, long offset, long length) {
return new ByteSourcePayload(content.slice(offset, length));
}