/**
* Special constructor used for RPC ownership transfer. Takes a snapshot slice of the current buf
* but points directly to the underlying UnsafeLittleEndian buffer. Does this by calling unwrap()
* twice on the provided DrillBuf and expecting an UnsafeDirectLittleEndian buffer. This operation
* includes taking a new reference count on the underlying buffer and maintaining returning with a
* current reference count for itself (masking the underlying reference count).
*
* @param allocator
* @param a Allocator used when users try to receive allocator from buffer.
* @param b Accountor used for accounting purposes.
*/
public DrillBuf(BufferAllocator allocator, Accountor a, DrillBuf b) {
this(allocator, a, getUnderlying(b), b, 0, b.length, true);
assert b.unwrap().unwrap() instanceof UnsafeDirectLittleEndian;
b.unwrap().unwrap().retain();
}
private static ByteBuf getUnderlying(DrillBuf b) {
ByteBuf underlying = b.unwrap().unwrap();
return underlying.slice((int) (b.memoryAddress() - underlying.memoryAddress()), b.length);
}