scroll/contracts/docs/Overview.md

Overview

The above picture is the overview of the contract design. There are several components both in layer 1 and layer 2: L1/L2 Scroll Messenger, various L1/L2 Gateways and L1/L2 Gateway Router. Besides these, there is a Rollup component only in layer 1.

The followings are the detailed docs for each component (docs are generated automatically by @primitivefi/hardhat-dodoc plugin):

• L1 Scroll Messenger and L2 Scroll Messenger: Main entry for sending and relaying cross domain message.
• Rollup
• L1 Gateway Router and L2 Gateway Router: Router contract for depositing/withdrawing Ethers and ERC20 tokens.
• L1/L2 Gateways:
  • L1 Standard ERC20 Gateway and L2 Standard ERC20 Gateway
  • L1 WETH Gateway and L2 WETH Gateway
  • L1 ERC721 Gateway and L2 ERC721 Gateway
  • L1 ERC1155 Gateway and L2 ERC1155 Gateway
• ScrollStandardERC20Factory: The ScrollStandardERC20 token factory used by L2StandardERC20Gateway.

There are two main applications: Token Bridge and Cross Domain Messaging. You can find the documentations in the links below:

• Token Bridge: moving token from layer 1 to layer 2, or from layer 2 to layer 1.
• Cross Domain Messaging: sending data to layer 2 from layer 1, or sending data to layer 2 from layer 1. Basically, it will help to trigger function call cross layer. The token bridge also use cross domain messaging to achieve its functionality.