OrderLock

contract OrderLock {

 // double hash of designated output, i.e. hash256(satoshis + varint + output script)
 Sha256 hashOutput;

 // trailingPrevouts = concat all inputs (txid1 + vout1 + txid2 + vout2 + ...),
 // excluding first 2 inputs, i.e. cancel baton input and self input
 public function unlock(SigHashPreimage preimage, bytes trailingPrevouts, bool isCancel) {
     // c3 = SIGHASH_SINGLE | ANYONECANPAY, checks self input, self output
     SigHashType sigHashType = SigHashType(b'c3');
     if (isCancel) {
         // 42 = SIGHASH_NONE, checks all inputs, no outputs
         sigHashType = SigHashType(b'42');
         // token lock input txid + vout, 32 + 4 bytes
         bytes selfOutpoint = preimage[68 : 104];
         // cancel baton input, same locking tx as token lock input, vout must be 0
         bytes cancelOutpoint = selfOutpoint[: 32] + b'00000000';
         // reconstruct full prevouts, double hash, check against preimage hashPrevouts
         require(hash256(selfOutpoint + cancelOutpoint + trailingPrevouts) == preimage[4 : 36]);
     } else {
         // check against preimage hashOutputs, with SIGHASH_SINGLE, only self output is hashed
         require(preimage[len(preimage) - 40 : len(preimage) - 8] == this.hashOutput);
     }
     // check preimage
     require(Tx.checkPreimageAdvanced(
         preimage,
         PrivKey(0xeb1c653e7471a63154d06b27f95bb028a5e826b4e73665ed3effe549cc85b2cd),
         PubKey(b'02dca1e194dd541a47f4c85fea6a4d45bb50f16ed2fddc391bf80b525454f8b409'),
         0x377d4cbae29bc1e717958cb6b030f71e2e634e1e700991a0ea02181c6ba241f9,
         0x2cde0b36a3821ef6dbd1cc8d754dcbae97526904b063c2722da89735162d282f,
         b'2cde0b36a3821ef6dbd1cc8d754dcbae97526904b063c2722da89735162d282f',
         sigHashType
     ));
 }

}