add possibility to depost 0 tokens

contracts/optimism/DepositDataCodec.sol

@@ -27,8 +27,8 @@ contract DepositDataCodec {
         }
 
         DepositData memory depositData;
-        depositData.rate = uint256(bytes32(buffer[0:31]));
-        depositData.time = uint256(bytes32(buffer[32:63]));
+        depositData.rate = uint256(bytes32(buffer[0:32]));
+        depositData.time = uint256(bytes32(buffer[32:64]));
         depositData.data = buffer[64:];
 
         return depositData;

contracts/optimism/L1ERC20TokenBridge.sol

@@ -68,22 +68,7 @@ contract L1ERC20TokenBridge is
             revert ErrorSenderNotEOA();
         }
 
-        DepositData memory depositData;
-        depositData.rate = IERC20Wrapable(l1TokenNonRebasable).tokensPerStEth();
-        depositData.time = block.timestamp;
-        depositData.data = data_;
-
-        bytes memory encodedDepositData = encodeDepositData(depositData);
-
-        if (isRebasableTokenFlow(l1Token_, l2Token_)) {
-            IERC20(l1TokenRebasable).safeTransferFrom(msg.sender, address(this), amount_);
-            IERC20(l1TokenRebasable).approve(l1TokenNonRebasable, amount_);
-            uint256 wstETHAmount = IERC20Wrapable(l1TokenNonRebasable).wrap(amount_);
-            _initiateERC20Deposit(l1TokenRebasable, l2TokenRebasable, msg.sender, msg.sender, wstETHAmount, l2Gas_, encodedDepositData);
-        } else if (isNonRebasableTokenFlow(l1Token_, l2Token_)) {
-            IERC20(l1TokenNonRebasable).safeTransferFrom(msg.sender, address(this), amount_);
-            _initiateERC20Deposit(l1TokenNonRebasable, l2TokenNonRebasable, msg.sender, msg.sender, amount_, l2Gas_, encodedDepositData);
-        }
+        _depositERC20To(l1Token_, l2Token_, msg.sender, amount_, l2Gas_, data_);
     }
 
     /// @inheritdoc IL1ERC20Bridge
@@ -101,7 +86,7 @@ contract L1ERC20TokenBridge is
         onlySupportedL1Token(l1Token_)
         onlySupportedL2Token(l2Token_)
     {
-        _initiateERC20Deposit(l1Token_, l2Token_, msg.sender, to_, amount_, l2Gas_, data_);
+        _depositERC20To(l1Token_, l2Token_, to_, amount_, l2Gas_, data_);
     }
 
     /// @inheritdoc IL1ERC20Bridge
@@ -123,7 +108,7 @@ contract L1ERC20TokenBridge is
             uint256 stETHAmount = IERC20Wrapable(l1TokenNonRebasable).unwrap(amount_);
             IERC20(l1TokenRebasable).safeTransfer(to_, stETHAmount);
         } else if (isNonRebasableTokenFlow(l1Token_, l2Token_)) {
-            IERC20(l1Token_).safeTransfer(to_, amount_);
+            IERC20(l1TokenNonRebasable).safeTransfer(to_, amount_);
         }
 
         emit ERC20WithdrawalFinalized(
@@ -136,6 +121,38 @@ contract L1ERC20TokenBridge is
         );
     }
 
+    function _depositERC20To(
+        address l1Token_,
+        address l2Token_,
+        address to_,
+        uint256 amount_,
+        uint32 l2Gas_,
+        bytes calldata data_
+    ) internal {
+
+        DepositData memory depositData;
+        depositData.rate = IERC20Wrapable(l1TokenNonRebasable).tokensPerStEth();
+        depositData.time = block.timestamp;
+        depositData.data = data_;
+
+        bytes memory encodedDepositData = encodeDepositData(depositData);
+
+        if (amount_ == 0) {
+            _initiateERC20Deposit(l1Token_, l2Token_, msg.sender, to_, amount_, l2Gas_, encodedDepositData);
+            return;
+        }
+
+        if (isRebasableTokenFlow(l1Token_, l2Token_)) {
+            IERC20(l1TokenRebasable).safeTransferFrom(msg.sender, address(this), amount_);
+            IERC20(l1TokenRebasable).approve(l1TokenNonRebasable, amount_);
+            uint256 wstETHAmount = IERC20Wrapable(l1TokenNonRebasable).wrap(amount_);
+            _initiateERC20Deposit(l1TokenRebasable, l2TokenRebasable, msg.sender, to_, wstETHAmount, l2Gas_, encodedDepositData);
+        } else if (isNonRebasableTokenFlow(l1Token_, l2Token_)) {
+            IERC20(l1TokenNonRebasable).safeTransferFrom(msg.sender, address(this), amount_);
+            _initiateERC20Deposit(l1TokenNonRebasable, l2TokenNonRebasable, msg.sender, to_, amount_, l2Gas_, encodedDepositData);
+        }
+    }
+
     /// @dev Performs the logic for deposits by informing the L2 token bridge contract
     ///     of the deposit and calling safeTransferFrom to lock the L1 funds.
     /// @param from_ Account to pull the deposit from on L1

contracts/optimism/L2ERC20TokenBridge.sol

@@ -39,8 +39,6 @@ contract L2ERC20TokenBridge is
 
     address public immutable tokensRateOracle;
 
-
-
     /// @param messenger_ L2 messenger address being used for cross-chain communications
     /// @param l1TokenBridge_  Address of the corresponding L1 bridge
     /// @param l1TokenNonRebasable_ Address of the bridged token in the L1 chain
@@ -62,20 +60,12 @@ contract L2ERC20TokenBridge is
 
     /// @inheritdoc IL2ERC20Bridge
     function withdraw(
-        address l1Token_,
         address l2Token_,
         uint256 amount_,
         uint32 l1Gas_,
         bytes calldata data_
     ) external whenWithdrawalsEnabled onlySupportedL2Token(l2Token_) {
-        if(l2Token_ == l2TokenRebasable) {
-            uint256 shares = ERC20Rebasable(l2TokenRebasable).getSharesByTokens(amount_);
-            ERC20Rebasable(l2TokenRebasable).burnShares(msg.sender, shares);
-            _initiateWithdrawal(l1Token_, l2Token_, msg.sender, msg.sender, shares, l1Gas_, data_);
-        } else {
-            IERC20Bridged(l2TokenNonRebasable).bridgeBurn(msg.sender, amount_);
-            _initiateWithdrawal(l1Token_, l2Token_, msg.sender, msg.sender, amount_, l1Gas_, data_);
-        }
+        _withdrawTo(l2Token_, msg.sender, amount_, l1Gas_, data_);
     }
 
     /// @inheritdoc IL2ERC20Bridge
@@ -85,8 +75,28 @@ contract L2ERC20TokenBridge is
         uint256 amount_,
         uint32 l1Gas_,
         bytes calldata data_
-    ) external whenWithdrawalsEnabled onlySupportedL2Token(l2Token_) {
-        _initiateWithdrawal(l1TokenNonRebasable, l2Token_, msg.sender, to_, amount_, l1Gas_, data_);
+    ) external whenWithdrawalsEnabled onlySupportedL2Token(l2Token_) {        
+        _withdrawTo(l2Token_, to_, amount_, l1Gas_, data_);
+    }
+
+    function _withdrawTo(
+        address l2Token_,
+        address to_,
+        uint256 amount_,
+        uint32 l1Gas_,
+        bytes calldata data_
+    ) internal {
+        if (l2Token_ == l2TokenRebasable) {
+
+            uint256 shares = ERC20Rebasable(l2TokenRebasable).getSharesByTokens(amount_);
+            ERC20Rebasable(l2TokenRebasable).burnShares(msg.sender, shares);
+            _initiateWithdrawal(l1TokenRebasable, l2TokenRebasable, msg.sender, to_, shares, l1Gas_, data_);
+
+        } else if (l2Token_ == l2TokenNonRebasable) {
+
+            IERC20Bridged(l2TokenNonRebasable).bridgeBurn(msg.sender, amount_);
+            _initiateWithdrawal(l2TokenNonRebasable, l2TokenNonRebasable, msg.sender, to_, amount_, l1Gas_, data_);
+        }
     }
 
     /// @inheritdoc IL2ERC20Bridge
@@ -112,6 +122,7 @@ contract L2ERC20TokenBridge is
         } else if (isNonRebasableTokenFlow(l1Token_, l2Token_)) {
             IERC20Bridged(l2TokenNonRebasable).bridgeMint(to_, amount_);
         }
+
         emit DepositFinalized(l1Token_, l2Token_, from_, to_, amount_, depositData.data);
     }
 

contracts/optimism/interfaces/IL2ERC20Bridge.sol

@@ -46,7 +46,6 @@ interface IL2ERC20Bridge {
     ///     solely as a convenience for external contracts. Aside from enforcing a maximum
     ///     length, these contracts provide no guarantees about its content.
     function withdraw(
-        address l1Token_,
         address l2Token_,
         uint256 amount_,
         uint32 l1Gas_,

contracts/stubs/ERC20WrapableStub.sol

@@ -15,13 +15,12 @@ contract ERC20WrapableStub is IERC20Wrapable, ERC20 {
 
     IERC20 public stETH;
     address public bridge;
-    uint256 public tokensRate; /// wst/st
+    uint256 public tokensRate;
 
     constructor(IERC20 stETH_, string memory name_, string memory symbol_)
         ERC20(name_, symbol_)
     {
         stETH = stETH_;
-        console.log("constructor wrap stETH=",address(stETH));
 
         tokensRate = 2 * 10 **18;
         _mint(msg.sender, 1000000 * 10**18);