ExitHelper

The IExitHelper interface is a helper contract that processes exits from stored event roots in CheckpointManager. It allows users to perform an exit for one or multiple events. This user guide will explain how to interact with the functions provided by the IExitHelper interface.

Functions

exit()

This function allows you to perform an exit for one event.

Parameters

• blockNumber (uint256): The block number of the exit event on L2.
• leafIndex (uint256): The leaf index in the exit event Merkle tree.
• unhashedLeaf (bytes): The ABI-encoded exit event leaf.
• proof (bytes32[]): The proof of the event inclusion in the tree.

Usage

To exit an event, call the exit() function with the required parameters:

IExitHelper.exitHelperInstance.exit(blockNumber, leafIndex, unhashedLeaf, proof);

batchExit()

This function allows you to perform a batch exit for multiple events.

Parameters

• inputs (BatchExitInput[]): An array of BatchExitInput structs, where each struct contains the following fields:
  • blockNumber (uint256): The block number of the exit event on L2.
  • leafIndex (uint256): The leaf index in the exit event Merkle tree.
  • unhashedLeaf (bytes): The ABI-encoded exit event leaf.
  • proof (bytes32[]): The proof of the event inclusion in the tree.

Usage

To perform a batch exit for multiple events, create an array of BatchExitInput structs and call the batchExit() function:

let batchExitInputs = [
  {
    blockNumber: blockNumber1,
    leafIndex: leafIndex1,
    unhashedLeaf: unhashedLeaf1,
    proof: proof1
  },
  {
    blockNumber: blockNumber2,
    leafIndex: leafIndex2,
    unhashedLeaf: unhashedLeaf2,
    proof: proof2
  }
];

IExitHelper.exitHelperInstance.batchExit(batchExitInputs);

This will process exits for multiple events in a single transaction, which can save gas and improve efficiency.