Merge pull request #265 from sCrypt-Inc/logical-utxo

Logical utxo

.gitignore

@@ -9,4 +9,3 @@ artifacts/
 .env
 scrypt.index.json
 .eslintcache
-tsconfig-scryptTS.json

package.json

@@ -26,7 +26,7 @@
  "author": "",
  "license": "MIT",
  "dependencies": {
- "scrypt-ts": "^1.3.0",
+ "scrypt-ts": "^1.3.1",
  "scrypt-ts-lib": "^0.1.20"
  },
  "devDependencies": {

src/contracts/virtualUTXO.ts

@@ -0,0 +1,112 @@
+import {
+ assert,
+ hash256,
+ int2ByteString,
+ method,
+ Sig,
+ SigHash,
+ slice,
+ SmartContract,
+ len,
+ byteString2Int,
+ prop,
+ UTXO,
+ bsv,
+} from 'scrypt-ts'
+
+export class VirtualUTXO extends SmartContract {
+ static readonly LOGICAL_UTXO_SIZE = 3
+
+ @prop(true)
+ dummyStateProp: bigint
+
+ constructor() {
+ super(...arguments)
+ this.dummyStateProp = 0n
+ }
+
+ @method(SigHash.SINGLE)
+ public unlock() {
+ // Get prevouts array and verify it.
+ const prevouts = this.prevouts
+ assert(
+ hash256(prevouts) == this.ctx.hashPrevouts,
+ 'hashPrevouts mismatch'
+ )
+
+ // The prevout of the current input which is being executed.
+ const currentPrevout =
+ this.ctx.utxo.outpoint.txid +
+ int2ByteString(this.ctx.utxo.outpoint.outputIndex, 4n)
+
+ for (let i = 0; i < VirtualUTXO.LOGICAL_UTXO_SIZE; i++) {
+ const start = BigInt(i) * 36n
+ const end = start + 36n
+ const prevout = slice(prevouts, start, end)
+
+ // Within the prevouts array, find the prevout for the currently executed input.
+ if (prevout == currentPrevout) {
+ const currentPrevoutTXID = slice(currentPrevout, 0n, 32n)
+ const currentPrevoutOutputIndex = byteString2Int(
+ slice(currentPrevout, 32n, 36n)
+ )
+
+ const isLastInput = i == VirtualUTXO.LOGICAL_UTXO_SIZE - 1
+
+ // Check the subsequent input is unlocking the subsequent output index from the same transaction.
+ // If the last input is being executed, the subsequent input is the FIRST one. This ensures a circular
+ // verification structure.
+ const startNext = isLastInput ? 0n : end
+ const nextPrevout = slice(prevouts, startNext, startNext + 36n)
+ const nextPrevoutTXID = slice(nextPrevout, 0n, 32n)
+ const nextPrevoutOutputIndex = byteString2Int(
+ slice(nextPrevout, 32n, 36n)
+ )
+ assert(
+ currentPrevoutTXID == nextPrevoutTXID,
+ 'next input TXID mismatch'
+ )
+ assert(
+ nextPrevoutOutputIndex ==
+ (isLastInput ? 0n : currentPrevoutOutputIndex + 1n),
+ 'next input not unlocking subsequent output idx'
+ )
+ }
+ }
+
+ // Propagate contract.
+ const outputs = this.buildStateOutput(this.ctx.utxo.value)
+ assert(hash256(outputs) == this.ctx.hashOutputs, 'hashOutputs mismatch')
+ }
+
+ // Customize the deployment TX to include multiple instances of this smart contract,
+ // equal to the specified size of our logical UTXO.
+ override async buildDeployTransaction(
+ utxos: UTXO[],
+ amount: number,
+ changeAddress?: bsv.Address | string
+ ): Promise<bsv.Transaction> {
+ const deployTx = new bsv.Transaction()
+ // Add p2pkh inputs for paying tx fees.
+ .from(utxos)
+
+ // Add logical UTXO outputs.
+ for (let i = 0; i < VirtualUTXO.LOGICAL_UTXO_SIZE; i++) {
+ deployTx.addOutput(
+ new bsv.Transaction.Output({
+ script: this.lockingScript,
+ satoshis: amount,
+ })
+ )
+ }
+
+ if (changeAddress) {
+ deployTx.change(changeAddress)
+ if (this._provider) {
+ deployTx.feePerKb(await this.provider.getFeePerKb())
+ }
+ }
+
+ return deployTx
+ }
+}

tests/local/ordinalAuction.test.ts

@@ -8,7 +8,6 @@ import {
  MethodCallOptions,
  PubKey,
  reverseByteString,
- Sig,
  toByteString,
  toHex,
  Utils,
@@ -101,9 +100,7 @@ describe('Test SmartContract `OrdinalAuction`', () => {
  'close',
  async (
  current: OrdinalAuction,
- options: MethodCallOptions<OrdinalAuction>,
- sigAuctioneer: Sig,
- prevouts: ByteString
+ options: MethodCallOptions<OrdinalAuction>
  ) => {
  const unsignedTx: bsv.Transaction = new bsv.Transaction()
 
@@ -164,45 +161,7 @@ describe('Test SmartContract `OrdinalAuction`', () => {
  }
  )
 
- let contractTx = await currentInstance.methods.close(
- (sigResps) => findSig(sigResps, publicKeyAuctioneer),
- {
- fromUTXO,
- pubKeyOrAddrToSign: publicKeyAuctioneer,
- changeAddress: addressAuctioneer,
- lockTime: auctionDeadline + 1,
- sequence: 0,
- exec: false, // Do not execute the contract yet, only get the created calling transaction.
- } as MethodCallOptions<OrdinalAuction>
- )
-
- currentInstance.bindTxBuilder(
- 'close',
- async (
- current: OrdinalAuction,
- options: MethodCallOptions<OrdinalAuction>,
- sigAuctioneer: Sig,
- prevouts: ByteString
- ) => {
- return Promise.resolve({
- tx: contractTx.tx,
- atInputIndex: 1,
- nexts: [],
- })
- }
- )
-
- // Assemble prevouts byte string.
- let prevouts = toByteString('')
- contractTx.tx.inputs.forEach((input) => {
- prevouts += reverseByteString(
- toByteString(input.prevTxId.toString('hex')),
- 32n
- )
- prevouts += int2ByteString(BigInt(input.outputIndex), 4n)
- })
-
- contractTx = await currentInstance.methods.close(
+ const contractTx = await currentInstance.methods.close(
  (sigResps) => findSig(sigResps, publicKeyAuctioneer),
  {
  fromUTXO,