add updated EVM contract methods

cadence/contracts/standards/EVM.cdc

@@ -17,6 +17,18 @@ contract EVM {
     access(all)
     event CadenceOwnedAccountCreated(addressBytes: [UInt8; 20])
 
+    /// FLOWTokensDeposited is emitted when FLOW tokens is bridged
+    /// into the EVM environment. Note that this event is not emitted
+    /// for transfer of flow tokens between two EVM addresses.
+    access(all)
+    event FLOWTokensDeposited(addressBytes: [UInt8; 20], amount: UFix64)
+
+    /// FLOWTokensWithdrawn is emitted when FLOW tokens are bridged
+    /// out of the EVM environment. Note that this event is not emitted
+    /// for transfer of flow tokens between two EVM addresses.
+    access(all)
+    event FLOWTokensWithdrawn(addressBytes: [UInt8; 20], amount: UFix64)
+
     /// EVMAddress is an EVM-compatible address
     access(all)
     struct EVMAddress {
@@ -66,10 +78,15 @@ contract EVM {
         /// Deposits the given vault into the EVM account with the given address
         access(all)
         fun deposit(from: @FlowToken.Vault) {
+            let amount = from.balance
+            if amount == 0.0 {
+                panic("calling deposit function with an empty vault is not allowed")
+            }
             InternalEVM.deposit(
                 from: <-from,
                 to: self.bytes
             )
+            emit FLOWTokensDeposited(addressBytes: self.bytes, amount: amount)
         }
     }
 
@@ -110,6 +127,12 @@ contract EVM {
         view fun inAttoFLOW(): UInt {
             return self.attoflow
         }
+
+        /// Returns true if the balance is zero
+        access(all)
+        fun isZero(): Bool {
+            return self.attoflow == 0
+        }
     }
 
     /// reports the status of evm execution.
@@ -220,10 +243,7 @@ contract EVM {
         /// Deposits the given vault into the cadence owned account's balance
         access(all)
         fun deposit(from: @FlowToken.Vault) {
-            InternalEVM.deposit(
-                from: <-from,
-                to: self.addressBytes
-            )
+            self.address().deposit(from: <-from)
         }
 
         /// The EVM address of the cadence owned account behind an entitlement, acting as proof of access
@@ -239,10 +259,14 @@ contract EVM {
         /// rounding error, this function would fail.
         access(Owner | Withdraw)
         fun withdraw(balance: Balance): @FlowToken.Vault {
+            if balance.isZero() {
+                panic("calling withdraw function with zero balance is not allowed")
+            }
             let vault <- InternalEVM.withdraw(
                 from: self.addressBytes,
                 amount: balance.attoflow
             ) as! @FlowToken.Vault
+            emit FLOWTokensWithdrawn(addressBytes: self.addressBytes, amount: balance.inFLOW())
             return <-vault
         }
 
@@ -484,7 +508,6 @@ contract EVM {
         }
 
         let coaRef = acc.capabilities.borrow<&EVM.CadenceOwnedAccount>(path)
-
         if coaRef == nil {
              return ValidationResult(
                  isValid: false,
@@ -509,14 +532,6 @@ contract EVM {
         )
     }
 
-    /// Returns a reference to the BridgeAccessor designated for internal bridge requests
-    access(self)
-    view fun borrowBridgeAccessor(): auth(Bridge) &{BridgeAccessor} {
-        return self.account.storage.borrow<auth(Bridge) &{BridgeRouter}>(from: /storage/evmBridgeRouter)
-            ?.borrowBridgeAccessor()
-            ?? panic("Could not borrow reference to the EVM bridge")
-    }
-
     /// Interface for a resource which acts as an entrypoint to the VM bridge
     access(all)
     resource interface BridgeAccessor {
@@ -563,4 +578,12 @@ contract EVM {
         /// Returns a reference to the BridgeAccessor designated for internal bridge requests
         access(Bridge) view fun borrowBridgeAccessor(): auth(Bridge) &{BridgeAccessor}
     }
+
+    /// Returns a reference to the BridgeAccessor designated for internal bridge requests
+    access(self)
+    view fun borrowBridgeAccessor(): auth(Bridge) &{BridgeAccessor} {
+        return self.account.storage.borrow<auth(Bridge) &{BridgeRouter}>(from: /storage/evmBridgeRouter)
+            ?.borrowBridgeAccessor()
+            ?? panic("Could not borrow reference to the EVM bridge")
+    }
 }