/**
* Build a 'getblocks' message
*
* @param peer Destination peer
* @param blockList Block hash list
* @param stopBlock Stop block hash (Sha256Hash.ZERO_HASH to get all blocks)
* @return 'getblocks' message
*/
public static Message buildGetBlocksMessage(
Peer peer, List<Sha256Hash> blockList, Sha256Hash stopBlock) {
//
// Build the message payload
//
// The protocol version will be set to the lesser of our version and the peer version
//
SerializedBuffer msgBuffer = new SerializedBuffer(blockList.size() * 32 + 40);
msgBuffer
.putInt(Math.min(peer.getVersion(), NetParams.PROTOCOL_VERSION))
.putVarInt(blockList.size());
for (Sha256Hash hash : blockList) {
msgBuffer.putBytes(Helper.reverseBytes(hash.getBytes()));
}
msgBuffer.putBytes(Helper.reverseBytes(stopBlock.getBytes()));
//
// Build the message
//
ByteBuffer buffer = MessageHeader.buildMessage("getblocks", msgBuffer);
return new Message(buffer, peer, MessageHeader.MessageCommand.GETBLOCKS);
}
/**
* Process the 'getblocks' message and return an 'inv' message
*
* @param msg Message
* @param inBuffer Input buffer
* @param msgListener Message listener
* @throws EOFException End-of-data processing stream
* @throws VerificationException Message verification failed
*/
public static void processGetBlocksMessage(
Message msg, SerializedBuffer inBuffer, MessageListener msgListener)
throws EOFException, VerificationException {
//
// Process the message
//
int version = inBuffer.getInt();
if (version < NetParams.MIN_PROTOCOL_VERSION)
throw new VerificationException(
String.format("Protocol version %d is not supported", version));
int count = inBuffer.getVarInt();
if (count < 0 || count > 500)
throw new VerificationException("More than 500 locator entries in 'getblocks' message");
List<Sha256Hash> blockList = new ArrayList<>(count);
for (int i = 0; i < count; i++)
blockList.add(new Sha256Hash(Helper.reverseBytes(inBuffer.getBytes(32))));
Sha256Hash stopBlock = new Sha256Hash(Helper.reverseBytes(inBuffer.getBytes(32)));
//
// Notify the message listener
//
msgListener.processGetBlocks(msg, version, blockList, stopBlock);
}