feat: create meta-evidence with contract

package.json

@@ -67,6 +67,7 @@
   "dependencies": {
     "babel-runtime": "^6.26.0",
     "eth-sig-util": "^1.4.2",
+    "ethereumjs-util": "^5.2.0",
     "kleros": "^0.0.6",
     "kleros-interaction": "^0.0.17",
     "lodash": "^4.17.4",

src/contracts/abstractions/Arbitrable.js

@@ -1,5 +1,7 @@
 import AbstractContract from '../AbstractContract'
 
+import getContractAddress from '../../utils/getContractAddress'
+
 /**
  * Arbitrable Abstract Contarct API. This wraps an arbitrable contract. It provides
  * interaction with both the off chain store as well as the arbitrable instance. All
@@ -33,8 +35,14 @@ class ArbitrableContract extends AbstractContract {
     email = '',
     title = '',
     description = '',
+    metaEvidence = {}
     ...args
   ) => {
+    const web3Provider = this._contractImplementation.getWeb3Provider()
+    // determine the contract address WARNING if the nonce changes this will produce a different address
+    const contractAddress = getContractAddress(account, web3Provider)
+    const metaEvidenceUri = this._StoreProvider.getMetaEvidenceUri(contractAddress)
+
     const contractInstance = await this._contractImplementation.constructor.deploy(
       account,
       value,
@@ -43,10 +51,14 @@ class ArbitrableContract extends AbstractContract {
       timeout,
       partyB,
       arbitratorExtraData,
-      this._contractImplementation.getWeb3Provider(),
+      metaEvidenceUri,
+      web3Provider,
       ...args
     )
 
+    if (contractInstance.address !== contractAddress)
+      raise new Error('Contract address does not match meta-evidence uri')
+
     const newContract = await this._StoreProvider.updateContract(
       account,
       contractInstance.address,
@@ -58,7 +70,8 @@ class ArbitrableContract extends AbstractContract {
         timeout,
         email,
         title,
-        description
+        description,
+        metaEvidence
       }
     )
 

src/utils/StoreProviderWrapper.js

@@ -75,6 +75,11 @@ class StoreProviderWrapper {
   queueReadRequest = uri =>
     this._storeQueue.fetch(() => this._makeRequest('GET', uri))
 
+
+  getMetaEvidenceUri = address => (
+    `${this._storeUri}/${userAddress}/contracts/${address}/meta-evidence`
+  )
+
   // **************************** //
   // *          Read            * //
   // **************************** //

src/utils/Web3Wrapper.js

@@ -18,6 +18,8 @@ class Web3Wrapper {
 
   getCoinbase = () => this._web3.eth.coinbase
 
+  getNonce = address => this._web3.eth.getTransactionCount(address)
+
   toWei = (amount, unit) => {
     const newAmount = this._web3.toWei(amount, unit)
     return newAmount.toNumber ? newAmount.toNumber() : Number(newAmount)

src/utils/getContractAddress.js

@@ -0,0 +1,6 @@
+import ethUtil from 'ethereumjs-util'
+
+const getContractAddress (account, Web3Wrapper) => {
+  const currentNonce = Web3Wrapper.getNonce(account)
+  return ethUtil.bufferToHex(ethUtil.generateAddress(account, currentNonce))
+}

yarn.lock

@@ -3418,7 +3418,7 @@ eth-sig-util@^1.4.2:
     bn.js "^4.10.0"
     ethereumjs-util "^5.0.0"
 
-ethereumjs-util@^5.0.0, ethereumjs-util@^5.1.1:
+ethereumjs-util@^5.0.0, ethereumjs-util@^5.1.1, ethereumjs-util@^5.2.0:
   version "5.2.0"
   resolved "https://registry.yarnpkg.com/ethereumjs-util/-/ethereumjs-util-5.2.0.tgz#3e0c0d1741471acf1036052d048623dee54ad642"
   dependencies: