Channel contracts (#279)

* Add support for contracts in state channels

* Remove console.log

* Remove console.log

* Improve channel rpc usage (#275)

* Improve channel rpc usage

* Fix lint error

* Remove unreachable code

* Improve channel tests and error handling (#276)

* Make sure that sign function is correctly called

* Improve error handling for update method

* Improve state channel params handling. Fixes #299 (#300)

es/channel/handlers.js

@@ -15,7 +15,7 @@
  *  PERFORMANCE OF THIS SOFTWARE.
  */
 
-import { generateKeyPair } from '../utils/crypto'
+import { generateKeyPair, encodeContractAddress } from '../utils/crypto'
 import {
   options,
   changeStatus,
@@ -24,6 +24,7 @@ import {
   emit,
   channelId
 } from './internal'
+import { unpackTx } from '../tx/builder'
 
 export function awaitingConnection (channel, message, state) {
   if (message.method === 'channels.info') {
@@ -310,6 +311,56 @@ export function awaitingDepositCompletion (channel, message, state) {
   }
 }
 
+export async function awaitingNewContractTx (channel, message, state) {
+  if (message.method === 'channels.sign.update') {
+    const signedTx = await Promise.resolve(state.sign(message.params.data.tx))
+    send(channel, { jsonrpc: '2.0', method: 'channels.update', params: { tx: signedTx } })
+    return { handler: awaitingNewContractCompletion, state }
+  }
+}
+
+export function awaitingNewContractCompletion (channel, message, state) {
+  if (message.method === 'channels.update') {
+    const { round } = unpackTx(message.params.data.state).tx.encodedTx.tx
+    // eslint-disable-next-line standard/computed-property-even-spacing
+    const owner = options.get(channel)[{
+      initiator: 'initiatorId',
+      responder: 'responderId'
+    }[options.get(channel).role]]
+    changeState(channel, message.params.data.state)
+    state.resolve({
+      accepted: true,
+      address: encodeContractAddress(owner, round),
+      state: message.params.data.state
+    })
+    return { handler: channelOpen }
+  }
+  if (message.method === 'channels.conflict') {
+    state.resolve({ accepted: false })
+    return { handler: channelOpen }
+  }
+}
+
+export async function awaitingCallContractUpdateTx (channel, message, state) {
+  if (message.method === 'channels.sign.update') {
+    const signedTx = await Promise.resolve(state.sign(message.params.data.tx))
+    send(channel, { jsonrpc: '2.0', method: 'channels.update', params: { tx: signedTx } })
+    return { handler: awaitingCallContractCompletion, state }
+  }
+}
+
+export function awaitingCallContractCompletion (channel, message, state) {
+  if (message.method === 'channels.update') {
+    changeState(channel, message.params.data.state)
+    state.resolve({ accepted: true, state: message.params.data.state })
+    return { handler: channelOpen }
+  }
+  if (message.method === 'channels.conflict') {
+    state.resolve({ accepted: false })
+    return { handler: channelOpen }
+  }
+}
+
 export function channelClosed (channel, message, state) {
   return { handler: channelClosed }
 }

es/channel/index.js

@@ -23,6 +23,7 @@
  */
 
 import AsyncInit from '../utils/async-init'
+import { snakeToPascal } from '../utils/string'
 import * as handlers from './handlers'
 import {
   eventEmitters,
@@ -192,7 +193,7 @@ function shutdown (sign) {
   return new Promise((resolve) => {
     enqueueAction(
       this,
-      (channel, state) => true,
+      (channel, state) => state.handler === handlers.channelOpen,
       (channel, state) => {
         send(channel, { jsonrpc: '2.0', method: 'channels.shutdown', params: {} })
         return {
@@ -297,6 +298,136 @@ function deposit (amount, sign, { onOnChainTx, onOwnDepositLocked, onDepositLock
   })
 }
 
+/**
+ * Create a contract
+ *
+ * @param {object} options
+ * @param {string} [options.code] - Api encoded compiled AEVM byte code
+ * @param {string} [options.callData] - Api encoded compiled AEVM call data for the code
+ * @param {number} [options.deposit] - Initial amount the owner of the contract commits to it
+ * @param {number} [options.vmVersion] - Version of the AEVM
+ * @param {number} [options.abiVersion] - Version of the ABI
+ * @param {function} sign - Function which verifies and signs create contract transaction
+ * @return {Promise<object>}
+ * @example channel.createContract({
+ *   code: 'cb_HKtpipK4aCgYb17wZ...',
+ *   callData: 'cb_1111111111111111...',
+ *   deposit: 10,
+ *   vmVersion: 3,
+ *   abiVersion: 1
+ * }).then(({ accepted, state, address }) => {
+ *   if (accepted) {
+ *     console.log('New contract has been created')
+ *     console.log('Contract address:', address)
+ *   } else {
+ *     console.log('New contract has been rejected')
+ *   }
+ * })
+ */
+function createContract ({ code, callData, deposit, vmVersion, abiVersion }, sign) {
+  return new Promise((resolve) => {
+    enqueueAction(
+      this,
+      (channel, state) => state.handler === handlers.channelOpen,
+      (channel, state) => {
+        send(channel, {
+          jsonrpc: '2.0',
+          method: 'channels.update.new_contract',
+          params: {
+            code,
+            call_data: callData,
+            deposit,
+            vm_version: vmVersion,
+            abi_version: abiVersion
+          }
+        })
+        return {
+          handler: handlers.awaitingNewContractTx,
+          state: {
+            sign,
+            resolve
+          }
+        }
+      }
+    )
+  })
+}
+
+/**
+ * Call a contract
+ *
+ * @param {object} options
+ * @param {string} [options.amount] - Amount the caller of the contract commits to it
+ * @param {string} [options.callData] - ABI encoded compiled AEVM call data for the code
+ * @param {number} [options.contract] - Address of the contract to call
+ * @param {number} [options.abiVersion] - Version of the ABI
+ * @param {function} sign - Function which verifies and signs contract call transaction
+ * @return {Promise<object>}
+ * @example channel.callContract({
+ *   contract: 'ct_9sRA9AVE4BYTAkh5RNfJYmwQe1NZ4MErasQLXZkFWG43TPBqa',
+ *   callData: 'cb_1111111111111111...',
+ *   amount: 0,
+ *   abiVersion: 1
+ * }).then(({ accepted, state }) => {
+ *   if (accepted) {
+ *     console.log('Contract called succesfully')
+ *     console.log('The new state is:', state)
+ *   } else {
+ *     console.log('Contract call has been rejected')
+ *   }
+ * })
+ */
+function callContract ({ amount, callData, contract, abiVersion }, sign) {
+  return new Promise((resolve) => {
+    enqueueAction(
+      this,
+      (channel, state) => state.handler === handlers.channelOpen,
+      (channel, state) => {
+        send(channel, {
+          jsonrpc: '2.0',
+          method: 'channels.update.call_contract',
+          params: {
+            amount,
+            call_data: callData,
+            contract,
+            abi_version: abiVersion
+          }
+        })
+        return {
+          handler: handlers.awaitingCallContractUpdateTx,
+          state: { resolve, sign }
+        }
+      }
+    )
+  })
+}
+
+/**
+ * Get contract call result
+ *
+ * @param {object} options
+ * @param {string} [options.caller] - Address of contract caller
+ * @param {string} [options.contract] - Address of the contract
+ * @param {number} [options.round] - Round when contract was called
+ * @return {Promise<object>}
+ * @example channel.getContractCall({
+ *   caller: 'ak_Y1NRjHuoc3CGMYMvCmdHSBpJsMDR6Ra2t5zjhRcbtMeXXLpLH',
+ *   contract: 'ct_9sRA9AVE4BYTAkh5RNfJYmwQe1NZ4MErasQLXZkFWG43TPBqa',
+ *   round: 3
+ * }).then(({ returnType, returnValue }) => {
+ *   if (returnType === 'ok') console.log(returnValue)
+ * })
+ */
+async function getContractCall ({ caller, contract, round }) {
+  const result = await call(this, 'channels.get.contract_call', { caller, contract, round })
+  return R.fromPairs(
+    R.map(
+      ([key, value]) => ([snakeToPascal(key), value]),
+      R.toPairs(result)
+    )
+  )
+}
+
 /**
  * Send generic message
  *
@@ -382,7 +513,10 @@ const Channel = AsyncInit.compose({
     shutdown,
     sendMessage,
     withdraw,
-    deposit
+    deposit,
+    createContract,
+    callContract,
+    getContractCall
   }
 })
 

es/utils/crypto.js

@@ -208,6 +208,32 @@ export function hexStringToByte (str) {
   return new Uint8Array(a)
 }
 
+/**
+ * Converts a positive integer to the smallest possible
+ * representation in a binary digit representation
+ * @rtype (value: Number) => Buffer
+ * @param {Number} value - Value to encode
+ * @return {Buffer} - Encoded data
+ */
+export function encodeUnsigned (value) {
+  const binary = Buffer.allocUnsafe(4)
+  binary.writeUInt32BE(value)
+  return binary.slice(binary.findIndex(i => i !== 0))
+}
+
+/**
+ * Compute contract address
+ * @rtype (owner: String, nonce: Number) => String
+ * @param {String} owner - Address of contract owner
+ * @param {Number} nonce - Round when contract was created
+ * @return {String} - Contract address
+ */
+export function encodeContractAddress (owner, nonce) {
+  const publicKey = decodeBase58Check(assertedType(owner, 'ak'))
+  const binary = Buffer.concat([publicKey, encodeUnsigned(nonce)])
+  return `ct_${encodeBase58Check(hash(binary))}`
+}
+
 // KEY-PAIR HELPERS
 
 /**

test/integration/channel.js

@@ -44,7 +44,7 @@ function waitForChannel (channel) {
   )
 }
 
-describe.only('Channel', function () {
+describe('Channel', function () {
   configure(this)
 
   let initiator
@@ -403,6 +403,92 @@ describe.only('Channel', function () {
     await Promise.all([waitForChannel(initiatorCh), waitForChannel(responderCh)])
     sinon.assert.notCalled(initiatorSign)
     sinon.assert.notCalled(responderSign)
+    await initiatorCh.leave()
+  })
+
+  it('can create a contract and accept', async () => {
+    initiatorCh = await Channel({
+      ...sharedParams,
+      role: 'initiator',
+      port: 3003,
+      sign: initiatorSign
+    })
+    responderCh = await Channel({
+      ...sharedParams,
+      role: 'responder',
+      port: 3003,
+      sign: responderSign
+    })
+    await Promise.all([waitForChannel(initiatorCh), waitForChannel(responderCh)])
+    const code = await initiator.compileContractAPI(identityContract)
+    const callData = await initiator.contractEncodeCallDataAPI(identityContract, 'init', [])
+    const result = await initiatorCh.createContract({
+      code,
+      callData,
+      deposit: 1000,
+      vmVersion: 3,
+      abiVersion: 1
+    }, async (tx) => await initiator.signTransaction(tx))
+    result.should.eql({ accepted: true, address: result.address, state: initiatorCh.state() })
+    contractAddress = result.address
+    contractEncodeCall = (method, args) => initiator.contractEncodeCallDataAPI(identityContract, method, args)
+  })
+
+  it('can create a contract and reject', async () => {
+    responderShouldRejectUpdate = true
+    const code = await initiator.compileContractAPI(identityContract)
+    const callData = await initiator.contractEncodeCallDataAPI(identityContract, 'init', [])
+    const result = await initiatorCh.createContract({
+      code,
+      callData,
+      deposit: 1000,
+      vmVersion: 3,
+      abiVersion: 1
+    }, async (tx) => await initiator.signTransaction(tx))
+    result.should.eql({ accepted: false })
+  })
+
+  it('can call a contract and accept', async () => {
+    const result = await initiatorCh.callContract({
+      amount: 0,
+      callData: await contractEncodeCall('main', ['42']),
+      contract: contractAddress,
+      abiVersion: 1
+    }, async (tx) => await initiator.signTransaction(tx))
+    result.should.eql({ accepted: true, state: initiatorCh.state() })
+    callerNonce = Number(unpackTx(initiatorCh.state()).tx.encodedTx.tx.round)
+  })
+
+  it('can call a contract and reject', async () => {
+    responderShouldRejectUpdate = true
+    const result = await initiatorCh.callContract({
+      amount: 0,
+      callData: await contractEncodeCall('main', ['42']),
+      contract: contractAddress,
+      abiVersion: 1
+    }, async (tx) => await initiator.signTransaction(tx))
+    result.should.eql({ accepted: false })
+  })
+
+  it('can get contract call', async () => {
+    const result = await initiatorCh.getContractCall({
+      caller: await initiator.address(),
+      contract: contractAddress,
+      round: callerNonce
+    })
+    result.should.eql({
+      callerId: await initiator.address(),
+      callerNonce,
+      contractId: contractAddress,
+      gasPrice: result.gasPrice,
+      gasUsed: result.gasUsed,
+      height: result.height,
+      log: result.log,
+      returnType: 'ok',
+      returnValue: result.returnValue
+    })
+    const value = await initiator.contractDecodeDataAPI('int', result.returnValue)
+    value.should.eql({ type: 'word', value: 42 })
   })
 
   it('can solo close a channel', async () => {