feat(sdk): update the sdk to detect permit from config

packages/extension/src/client/services/MetaMaskService/index.js

@@ -3,6 +3,7 @@ import * as ethUtil from 'ethereumjs-util';
 import Web3Service from '~/client/services/Web3Service';
 import registerExtension, { generateTypedData } from './registerExtension';
 import signNote from './signNote';
+import permitSchema from './permitSchema';
 import signProof from './signProof';
 
 const handleAction = async (action, params) => {
@@ -100,6 +101,37 @@ const handleAction = async (action, params) => {
             };
 
             break;
+        }
+            case 'metamask.eip712.permit': {
+                const {
+                    allowed,
+                    exipiry,
+                    nonce,
+                    spender,
+                    verifyingContract,
+                } = params;
+
+                const permitSchema = permit({
+                    allowed,
+                    exipiry,
+                    nonce,
+                    spender,
+                    verifyingContract
+                });
+                const method = 'eth_signTypedData_v4';
+                const { result } = await Web3Service.sendAsync({
+                    method,
+                    params: [address, permitSchema],
+                    from: address,
+                });
+
+                response = {
+                    signature: result,
+                };
+
+                break;
+            }
+            default:
         }
         default:
     }

packages/extension/src/client/services/MetaMaskService/permitSchema.js

@@ -0,0 +1,36 @@
+import { signer } from 'aztec.js';
+import utils from '@aztec/dev-utils';
+
+const {
+    constants: {
+        eip712,
+    },
+} = utils;
+
+
+export default ({
+    spender,
+    verifyingContract,
+    allowed,
+    expiry,
+    spender,
+    nonce
+}) => {
+    const domain = signer.generateDAIDomainparams(chainId, verifyingContract);
+    const schema = eip712.PERMIT_SIGNATURE;
+
+    const message = {
+        allowed,
+        spender,
+        expiry,
+        nonce,
+    };
+
+    const data = JSON.stringify({
+        ...schema,
+        message,
+        domain,
+    });
+
+    return data;
+};

packages/extension/src/config/supportsPermitSignature.js

@@ -0,0 +1,3 @@
+export default {
+    '0x6b175474e89094c44da98b954eedeac495271d0f': true,
+};

packages/extension/src/ui/apis/asset/permitERC20Allowance.js

@@ -0,0 +1,54 @@
+import ConnectionService from '~/ui/services/ConnectionService';
+import Web3Service from '~/helpers/Web3Service';
+
+export default async function permitERC20({
+    asset,
+    requestedAllowance,
+    allowanceSpender,
+}) {
+
+
+    const {
+        linkedTokenAddress,
+    } = asset;
+
+    let error;
+    try {
+       const nonce =  await Web3Service
+            .useContract('ERC20')
+            .at(linkedTokenAddress)
+            .method('nonces')
+            .send(
+                allowanceSpender,
+            );
+    } catch (e) {
+        error = e;
+    }
+    const exipry = Date.now() + 24 * 60 * 60;
+    const {
+        signature,
+        error,
+    } = await ConnectionService.post({
+        action: 'metamask.eip712.permit',
+        data: {
+            nonce,
+            expiry,
+            allowed: requestedAllowance
+            spender: allowanceSpender,
+        },
+    });
+
+    if (error) {
+        return {
+            error,
+        };
+    }
+
+    return {
+        spender: sender,
+        nonce,
+        expiry,
+        allowed; requestedAllowance,
+        signature,
+    };
+}

packages/extension/src/ui/pages/Deposit.jsx

@@ -53,6 +53,11 @@ const Deposit = ({
             steps = depositSteps.gsnTransfer;
         }
 
+        const tokenSupportsPermit = getTokenPermitStatus(asset.linkedTokenAddress);
+        if (tokenSupportsPermit) {
+            steps = depositSteps.gsnWithPermit;
+        }
+
         const allowance = await Web3Service
             .useContract('ERC20')
             .at(asset.linkedTokenAddress)
@@ -65,7 +70,7 @@ const Deposit = ({
         const erc20Amount = asset.scalingFactor.mul(new BN(amount));
         const requestedAllowance = erc20Amount;
         if (approvedERC20Allowance.gte(requestedAllowance)) {
-            steps = steps.filter(({ name }) => name !== 'approveERC20');
+            steps = steps.filter(({ name }) => name !== 'approveERC20' || 'permitERC20');
         }
 
         return {

packages/extension/src/ui/steps/deposit.js

@@ -13,6 +13,20 @@ const stepApproveERC20 = {
     submitTextKey: 'transaction.approve.submit',
 };
 
+
+const stepPermitERC20 = {
+    name: 'permitERC20',
+    descriptionKey: 'deposit.approve.description',
+    blockStyle: 'linked',
+    tasks: [
+        {
+            type: 'sign',
+            run: apis.asset.permitERC20Allowance,
+        },
+    ],
+    submitTextKey: 'transaction.approve.submit',
+};
+
 const stepConfirm = {
     name: 'confirmTransaction',
     descriptionKey: 'deposit.send.description',
@@ -121,6 +135,12 @@ export default {
         stepConfirmForGSN,
         stepTransferViaGSN,
     ],
+    gsnWithPermit: [
+        stepPermitERC20,
+        stepConfirmForGSN,
+        stepSendViaGSN,
+    ],
+
     metamask: [
         stepApproveERC20,
         stepConfirm,

packages/extension/src/ui/utils/makeToken.js

@@ -3,6 +3,8 @@ import {
     getResourceUrl,
 } from '~/utils/versionControl';
 
+import supportsPermit from '~/config/supportsPermitSignature';
+
 const publicResourcePath = getResourceUrl('public');
 
 const formatIconUrl = (icon) => {
@@ -24,5 +26,6 @@ export default function makeToken(address) {
         symbol,
         decimals,
         icon: formatIconUrl(logo),
+        supportsPermit: supportsPermit[address],
     };
 }