From e0c79c5812c80fbb5b89714b7ea02ebcca83e431 Mon Sep 17 00:00:00 2001
From: DarianShawn <DarianShawn007@gmail.com>
Date: Sun, 11 Sep 2022 19:53:32 +0800
Subject: [PATCH] Burn account amount when getting events from bridge contract

---
 contracts/abis/json.go     | 70 ++++++++++++++++++++++++++++++++++++++
 contracts/bridge/events.go | 45 ++++++++++++++++++++++++
 state/executor.go          | 10 ++++++
 3 files changed, 125 insertions(+)

diff --git a/contracts/abis/json.go b/contracts/abis/json.go
index 46d574d598..2ac7ed10fd 100644
--- a/contracts/abis/json.go
+++ b/contracts/abis/json.go
@@ -470,6 +470,26 @@ const BridgeJSONABI = `[
         "stateMutability": "nonpayable",
         "type": "constructor"
     },
+    {
+        "anonymous": false,
+        "inputs":
+        [
+            {
+                "indexed": true,
+                "internalType": "address",
+                "name": "sender",
+                "type": "address"
+            },
+            {
+                "indexed": true,
+                "internalType": "uint256",
+                "name": "amount",
+                "type": "uint256"
+            }
+        ],
+        "name": "Burned",
+        "type": "event"
+    },
     {
         "anonymous": false,
         "inputs":
@@ -646,6 +666,21 @@ const BridgeJSONABI = `[
         "name": "Withdrawn",
         "type": "event"
     },
+    {
+        "inputs":
+        [
+            {
+                "internalType": "uint256",
+                "name": "amount",
+                "type": "uint256"
+            }
+        ],
+        "name": "addBalance",
+        "outputs":
+        [],
+        "stateMutability": "nonpayable",
+        "type": "function"
+    },
     {
         "inputs":
         [
@@ -661,6 +696,26 @@ const BridgeJSONABI = `[
         "stateMutability": "nonpayable",
         "type": "function"
     },
+    {
+        "inputs":
+        [
+            {
+                "internalType": "address",
+                "name": "account",
+                "type": "address"
+            },
+            {
+                "internalType": "uint256",
+                "name": "amount",
+                "type": "uint256"
+            }
+        ],
+        "name": "burn",
+        "outputs":
+        [],
+        "stateMutability": "nonpayable",
+        "type": "function"
+    },
     {
         "inputs":
         [
@@ -862,6 +917,21 @@ const BridgeJSONABI = `[
         "stateMutability": "view",
         "type": "function"
     },
+    {
+        "inputs":
+        [
+            {
+                "internalType": "uint256",
+                "name": "amount",
+                "type": "uint256"
+            }
+        ],
+        "name": "subBalance",
+        "outputs":
+        [],
+        "stateMutability": "nonpayable",
+        "type": "function"
+    },
     {
         "inputs":
         [],
diff --git a/contracts/bridge/events.go b/contracts/bridge/events.go
index e4c585c53f..c58e845108 100644
--- a/contracts/bridge/events.go
+++ b/contracts/bridge/events.go
@@ -13,10 +13,12 @@ import (
 const (
 	EventDeposited = "Deposited"
 	EventWithdrawn = "Withdrawn"
+	EventBurned    = "Burned"
 
 	fieldReceiver = "receiver"
 	fieldAmount   = "amount"
 	fieldFee      = "fee"
+	fieldSender   = "sender"
 )
 
 // Frequently used methods. Must exist.
@@ -25,6 +27,8 @@ var (
 	BridgeDepositedEventID = types.Hash(BridgeDepositedEvent.ID())
 	BridgeWithdrawnEvent   = abis.BridgeABI.Events[EventWithdrawn]
 	BridgeWithdrawnEventID = types.Hash(BridgeWithdrawnEvent.ID())
+	BridgeEventBurnedEvent = abis.BridgeABI.Events[EventBurned]
+	BridgeBurnedEventID    = types.Hash(BridgeEventBurnedEvent.ID())
 )
 
 type DepositedLog struct {
@@ -125,3 +129,44 @@ func getBigIntFromWithdrawnLog(log map[string]interface{}, key string) (*big.Int
 
 	return bigVal, nil
 }
+
+type BurnedLog struct {
+	Sender types.Address
+	Amount *big.Int
+}
+
+func ParseBridgeBurnedLog(log *types.Log) (*BurnedLog, error) {
+	topics := make([]web3.Hash, 0, len(log.Topics))
+	for _, topic := range log.Topics {
+		topics = append(topics, web3.Hash(topic))
+	}
+
+	w3Log, err := BridgeEventBurnedEvent.ParseLog(&web3.Log{
+		Address: web3.Address(log.Address),
+		Topics:  topics,
+		Data:    log.Data,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	sender, ok := w3Log[fieldSender]
+	if !ok {
+		return nil, errors.New("address not exists in Deposited event")
+	}
+
+	account, ok := sender.(web3.Address)
+	if !ok {
+		return nil, errors.New("address downcast failed")
+	}
+
+	amount, err := getBigIntFromWithdrawnLog(w3Log, fieldAmount)
+	if err != nil {
+		return nil, err
+	}
+
+	return &BurnedLog{
+		Sender: types.Address(account),
+		Amount: amount,
+	}, nil
+}
diff --git a/state/executor.go b/state/executor.go
index 4d27c4a54e..9ff70c9bbb 100644
--- a/state/executor.go
+++ b/state/executor.go
@@ -339,6 +339,16 @@ func (t *Transition) handleBridgeLogs(msg *types.Transaction, logs []*types.Log)
 
 			// the fee goes to system Vault contract
 			t.state.AddBalance(systemcontracts.AddrVaultContract, parsedLog.Fee)
+		case bridge.BridgeBurnedEventID:
+			parsedLog, err := bridge.ParseBridgeBurnedLog(log)
+			if err != nil {
+				return err
+			}
+
+			// burn
+			if err := t.state.SubBalance(parsedLog.Sender, parsedLog.Amount); err != nil {
+				return err
+			}
 		}
 	}