coppr/merkletracker.py at master · XertroV/coppr · GitHub

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# start_debug
from ethereum import *
from contract_functions import *
from copy import deepcopy

class MERKLETRACKER(Contract):
	def run(self, tx, block):
		# variables for testing:
		minfee = 0

		# contract.blah is self-referential
		contract = self

		# end_debug

		# actual contract
		if tx.datan < 3:
			self.stop
		if tx.fee < minfee:
			stop

		def getmerkleroot(blockheader):
			return blockheader[4+32:4+32+32]

		if tx.data[0] == 0:
			# add a merkle root
			merkleroot = tx.data[1]
			blockhash = tx.data[2]
			blockdetails = block.contract_storage('CHAINHEADERS')[blockhash]
			if blockdetails == 0:
				self.stop("Blockhash doesn't exist in CHAINHEADERS")
			blockheader = blockdetails[0]
			if merkleroot != getmerkleroot(blockheader):
				# fail
				self.stop("merkleroot not in blockheader")
			contract.storage[merkleroot] = 1

		elif tx.data[0] == 1:
			# fill in merkle branch
			hash1 = tx.data[1]
			hash2 = tx.data[2]
			# first verify branch leads to existing entry
			counter = 2;
			while True:
				counter += 1
				hash3 = sha256(sha256(hash1.concat(hash2)))
				if tx.datan > counter:
					lr = tx.data[counter][0]
					hash4 = tx.data[counter][1:33]
				else:
					pre = contract.storage[hash3]
					if pre == 1:
						# found merkle root
						merkleroot = hash3
						break
					elif pre == 0:
						# failed, not enough user input to confirm branch
						self.stop('Incomplete or invalid merkle branch')
					merkleroot = pre[2]
					break
				if lr == 0:
					hash1 = hash3
					hash2 = hash4
				else:
					hash1 = hash4
					hash2 = hash3

			# sweet, everything is valid so far, lets make some entries!
			hash1 = tx.data[1]
			hash2 = tx.data[2]
			counter = 2;
			while contract.storage[hash1] == 0:
				contract.storage[hash1] = [0x00, hash2, merkleroot]
				contract.storage[hash2] = [0x01, hash1, merkleroot]
				counter += 1
				hash3 = sha256(hash1.concat(hash2))
				if tx.datan > counter:
					lr = tx.data[counter][0]
					hash4 = tx.data[counter][1:33]
				else:
					break
				if lr == 0:
					hash1 = hash3
					hash2 = hash4
				else:
					hash1 = hash4
					hash2 = hash3
			# should be done, I think