create erc-20 contract class

main/accounts/Account/index.ts

@@ -3,8 +3,8 @@ import { isValidAddress, addHexPrefix } from 'ethereumjs-util'
 import { Version } from 'eth-sig-util'
 
 import { AccessRequest, AccountRequest, Accounts, RequestMode, TransactionRequest } from '..'
-import { decodeContractCall } from '../../abi'
-import erc20 from '../../abi/erc20'
+import { decodeContractCall } from '../../contracts'
+import erc20 from '../../contracts/erc20'
 import nebulaApi from '../../nebula'
 import signers from '../../signers'
 import windows from '../../windows'
@@ -16,6 +16,7 @@ import { getType as getSignerType, Type as SignerType } from '../../signers/Sign
 
 import provider from '../../provider'
 import { ApprovalType } from '../../../resources/constants'
+import Erc20Contract from '../../contracts/erc20'
 
 const nebula = nebulaApi('accounts')
 
@@ -238,34 +239,37 @@ class FrameAccount {
   }
 
   private async checkForErc20Approve (req: TransactionRequest, calldata: string) {
-    const decodedData = erc20.decodeCallData(req.data.to || '', calldata)
-
-    if (decodedData && erc20.isApproval(decodedData)) {
-      const spender = decodedData.args[0].value
-        const amount = decodedData.args[1].value
-        const { decimals, name, symbol } = await erc20.getTokenData(provider, decodedData.contractAddress)
-
-        this.addRequiredApproval(
-          req,
-          ApprovalType.TokenSpendApproval,
-          {
-            decimals,
-            name,
-            symbol,
-            amount,
-            contract: decodedData.contractAddress
-          },
-          data => {
-            req.data.data = erc20.encodeFunctionData('approve', [spender, data.amount])
-
-            if (req.decodedData) {
-              req.decodedData.args[1].value = data.amount
-            }
+    const contractAddress = req.data.to
+    if (!contractAddress) return
+
+    const contract = new Erc20Contract(contractAddress, provider)
+    const decodedData = contract.decodeCallData(calldata)
+
+    if (decodedData && Erc20Contract.isApproval(decodedData)) {
+      const spender = decodedData.args[0].toLowerCase()
+      const amount = decodedData.args[1].toNumber()
+      const { decimals, name, symbol } = await contract.getTokenData()
+
+      this.addRequiredApproval(
+        req,
+        ApprovalType.TokenSpendApproval,
+        {
+          decimals,
+          name,
+          symbol,
+          amount,
+          contract: contractAddress
+        },
+        data => {
+          req.data.data = contract.encodeCallData('approve', [spender, data.amount])
+
+          if (req.decodedData) {
+            req.decodedData.args[1].value = data.amount
           }
-        )
+        }
+      )
 
-        req.decodedData = decodedData
-        this.update()
+      this.update()
     }
   }
 

main/accounts/types.ts

@@ -1,5 +1,5 @@
 import type { Version } from 'eth-sig-util'
-import type { DecodedCallData } from '../abi'
+import type { DecodedCallData } from '../contracts'
 import type { Chain } from '../chains'
 import type { TransactionData } from '../transaction'
 

main/contracts/erc20.ts

@@ -0,0 +1,73 @@
+import { TransactionDescription } from '@ethersproject/abi'
+import { Contract } from '@ethersproject/contracts'
+import { Web3Provider } from '@ethersproject/providers'
+import erc20Abi from '../externalData/balances/erc-20-abi'
+import type { Provider } from '../provider'
+
+function createWeb3ProviderWrapper (provider: Provider) {
+  const wrappedSend = (request: { method: string, params?: any[] }, cb: (error: any, response: any) => void) => {
+    provider.sendAsync({
+      method: request.method,
+      params: request.params || [],
+      id: 1,
+      jsonrpc: '2.0',
+      _origin: 'frame.eth' }, cb)
+  }
+
+  return {
+    sendAsync: wrappedSend,
+    send: wrappedSend
+  }
+}
+
+export default class Erc20Contract {
+  private contract: Contract
+
+  constructor (address: Address, provider: Provider) {
+    const web3Provider = new Web3Provider(createWeb3ProviderWrapper(provider))
+    this.contract = new Contract(address, erc20Abi, web3Provider)
+  }
+
+  static isApproval (data: TransactionDescription) {
+    return (
+      data.name === 'approve' &&
+      data.functionFragment.inputs.length === 2 &&
+      (data.functionFragment.inputs[0].name || '').toLowerCase().endsWith('spender') && data.functionFragment.inputs[0].type === 'address' &&
+      (data.functionFragment.inputs[1].name || '').toLowerCase().endsWith('value') && data.functionFragment.inputs[1].type === 'uint256'
+    )
+  }
+
+  decodeCallData (calldata: string) {
+    try {
+      return this.contract.interface.parseTransaction({ data: calldata })
+    } catch (e) {
+      // call does not match ERC-20 interface
+    }
+  }
+
+  encodeCallData (fn: string, params: any[]) {
+    return this.contract.interface.encodeFunctionData(fn, params)
+  }
+
+  async getTokenData () {
+    try {
+      const calls = await Promise.all([
+        this.contract.decimals(),
+        this.contract.name(),
+        this.contract.symbol()
+      ])
+
+      return {
+        decimals: calls[0],
+        name: calls[1],
+        symbol: calls[2]
+      }
+    } catch (e) {
+      return {
+        decimals: 0,
+        name: '',
+        symbol: ''
+      }
+    }
+  }
+}

package.json

@@ -104,7 +104,7 @@
     "@aragon/wrapper": "5.5.1",
     "@ethereumjs/common": "2.6.0",
     "@ethereumjs/tx": "3.4.0",
-    "@ethersproject/abi": "5.5.0",
+    "@ethersproject/contracts": "5.5.0",
     "@githubprimer/octicons-react": "8.5.0",
     "@ledgerhq/hw-app-eth": "6.23.1",
     "@ledgerhq/hw-transport-node-hid-noevents": "6.20.0",