Merge pull request #36 from provable-things/adds-allowance-check

feat(peg-ins): <- adds allowance check to that

cli.js

@@ -184,4 +184,4 @@ const main = _ => {
   }
 }
 
-main().catch(_err => console.error('✘', _err.message))
+main().catch(_err => console.error('✘', _err.message) || process.exit(1))

lib/check-allowance.js

@@ -0,0 +1,29 @@
+const { BigNumber } = require('ethers')
+const { logic } = require('ptokens-utils')
+const { getTokenContract } = require('./get-token-contract')
+
+const TIMEOUT_TIME = 3000
+
+const checkAllowanceIsSufficient = (
+  _amount,
+  _spenderAddress,
+  _ownerAddress,
+  _tokenAddress,
+  _signer,
+) =>
+  console.info(`✔ Checking spender ${_spenderAddress} has sufficient allowance for token ${_tokenAddress}...`) ||
+    logic.racePromise(
+      TIMEOUT_TIME,
+      getTokenContract(_tokenAddress, _signer).allowance,
+      [ _ownerAddress, _spenderAddress ],
+    )
+      .then(_allowance => {
+        if (_allowance.lt(BigNumber.from(_amount))) {
+          return Promise.reject(new Error(`Insufficient allowance to peg in! Got ${_allowance}, need ${_amount}!`))
+        } else {
+          console.info(`✔ Allowance of ${_allowance} is sufficient!`)
+          return
+        }
+      })
+
+module.exports = { checkAllowanceIsSufficient }

lib/check-endpoint.js

@@ -1,10 +1,21 @@
-const checkEndpoint = _provider =>
-  console.info('✔ Checking endpoint...') ||
-  _provider
-    .send('eth_blockNumber', [])
-    .then(_blockNumber =>
-      console.info(`✔ Endpoint working! Block height: ${parseInt(_blockNumber, 'hex')}`) || _provider
-    )
+const checkEndpoint = _provider => {
+  console.info('✔ Checking endpoint...')
+  let timeoutReference
+  const TIMEOUT_TIME = 2000
+
+  const rejectAfterX = _x =>
+    /* eslint-disable-next-line no-return-assign */
+    new Promise((resolve, reject) => timeoutReference = setTimeout(reject, _x, new Error('Timed out!')))
+
+  // NOTE: We can't use `ptokens-utils` `racePromise` for this because `ethers` is a hymn to OOP style
+  // programming. And so when we pass the promise fxn we want (`_provider.send`), then the `racePromise`
+  // tries to call it, we lose all reference to `this` inside `_provider.send`, which then throws an error.
+
+  return Promise.race([ _provider.send('eth_blockNumber', []), rejectAfterX(TIMEOUT_TIME) ])
+    .then(_blockNumberHex => parseInt(_blockNumberHex, 'hex'))
+    .then(_blockNumber => console.info(`✔ Endpoint working! Block height: ${_blockNumber}`) || _provider)
     .catch(_err => Promise.reject(new Error(`Endpoint error: ${_err.message}`)))
+    .finally(_ => clearTimeout(timeoutReference))
+}
 
 module.exports = { checkEndpoint }

lib/get-token-contract.js

@@ -0,0 +1,20 @@
+/* eslint-disable-next-line no-shadow */
+const ethers = require('ethers')
+
+const TOKEN_ABI = [{
+  'inputs': [
+    { 'internalType': 'address', 'name': 'holder', 'type': 'address' },
+    { 'internalType': 'address', 'name': 'spender', 'type': 'address' }
+  ],
+  'name': 'allowance',
+  'outputs': [ { 'internalType': 'uint256', 'name': '', 'type': 'uint256' } ],
+  'stateMutability': 'view',
+  'type': 'function'
+}]
+
+const getTokenContract = (_address, _signer) => {
+  console.info(`✔ Getting token contract @ '${_address}'...`)
+  return new ethers.Contract(_address, TOKEN_ABI, _signer)
+}
+
+module.exports = { getTokenContract }

lib/peg-in.js

@@ -1,4 +1,5 @@
 const { getVaultContract } = require('./get-vault-contract')
+const { checkAllowanceIsSufficient } = require('./check-allowance')
 const { callFxnInContractAndAwaitReceipt } = require('./contract-utils')
 
 const pegIn = (
@@ -8,14 +9,29 @@ const pegIn = (
   _destinationAddress,
   _destinactionChainId,
   _userData = '0x',
-) => {
-  console.info('✔ Pegging in...')
-  return getVaultContract(_deployedContractAddress)
-    .then(callFxnInContractAndAwaitReceipt(
-      'pegIn(uint256,address,string,bytes,bytes4)',
-      [ _amount, _tokenAddress, _destinationAddress, _userData, _destinactionChainId ]
-    ))
+) =>
+  console.info('✔ Pegging in...') ||
+  getVaultContract(_deployedContractAddress)
+    .then(_vaultContact => Promise.all([ _vaultContact, _vaultContact.signer.getAddress() ]))
+    .then(([ _vaultContract, _ownerAddress ]) =>
+      Promise.all([
+        _vaultContract,
+        checkAllowanceIsSufficient(
+          _amount,
+          _deployedContractAddress, // NOTE: This is the "spender" address, the vault in this case!
+          _ownerAddress,
+          _tokenAddress,
+          _vaultContract.provider,
+        )
+      ])
+    )
+    .then(([ _vaultContract ]) =>
+      callFxnInContractAndAwaitReceipt(
+        'pegIn(uint256,address,string,bytes,bytes4)',
+        [ _amount, _tokenAddress, _destinationAddress, _userData, _destinactionChainId ],
+        _vaultContract,
+      )
+    )
     .then(_receipt => console.info('✔ Success! Transaction receipt:\n', _receipt))
-}
 
 module.exports = { pegIn }