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deposit

Function Type: external payable
Function Signature: deposit(address,uint256)
Returns: void

Deposits host chain coins or ERC20 tokens from the host blockchain into the EVVM virtual blockchain. The function transfers assets from the user's wallet on the host blockchain to the Treasury contract and credits the equivalent balance in the EVVM system.

Parameters​

ParameterTypeDescription
tokenaddressToken contract address or address(0) for host chain coin
amountuint256Amount to deposit (must match msg.value for host chain coin)

Workflow​

Host Chain Coin Deposit Flow (when token == address(0)):

  1. Zero Check: Ensures msg.value > 0. Reverts with DepositAmountMustBeGreaterThanZero() if zero host chain coin is sent.
  2. Amount Validation: Verifies that amount exactly matches msg.value. Reverts with InvalidDepositAmount() if they don't match.
  3. EVVM Balance Credit: Calls addAmountToUser(msg.sender, address(0), msg.value) in the EVVM core contract to credit the user's internal host chain coin balance in the virtual blockchain.

ERC20 Deposit Flow (when token != address(0)):

  1. Host Chain Coin Validation: Ensures msg.value == 0 (no host chain coin should be sent with ERC20 deposits). Reverts with InvalidDepositAmount() if host chain coin is sent.
  2. Amount Validation: Ensures amount > 0. Reverts with DepositAmountMustBeGreaterThanZero() if amount is zero.
  3. Host Blockchain Transfer: Executes transferFrom(msg.sender, address(this), amount) to move tokens from user to Treasury contract on the host blockchain.
  4. EVVM Balance Credit: Calls addAmountToUser(msg.sender, token, amount) in the EVVM core contract to credit the user's internal token balance in the virtual blockchain.

Errors​

  • DepositAmountMustBeGreaterThanZero() — Reverted when attempting to deposit zero host chain coin or zero ERC20 amount.
  • InvalidDepositAmount() — Reverted when amount does not match msg.value for native coin deposits, or when native coin is sent alongside an ERC20 deposit.

Security & Notes​

  • ERC20 transfers use IERC20(token).transferFrom(msg.sender, address(this), amount) in the current implementation. Some tokens do not strictly follow the ERC20 spec (they may return false on failure or not return a boolean), so using a safe transfer helper (e.g., SafeTransferLib.safeTransferFrom) or validating the return value in tests is recommended.
  • The ERC20 transfer occurs before calling addAmountToUser(...). Be aware that non-standard tokens (or ERC777 hooks) could attempt reentrancy; tests should cover malicious token behaviour.
  • When depositing native coin (address(0)), the function requires msg.value == amount — the amount parameter is validated against msg.value to avoid ambiguity. Consider calling deposit(address(0), msg.value) for clarity in integrations.