viem/op-stack/utils/getSourceHash.ts

TypeScript Interface for Ethereum

// Adapted from https://github.com/ethereum-optimism/optimism/blob/develop/packages/core-utils/src/optimism/deposit-transaction.ts#L117

import type { ErrorType } from '../../errors/utils.js'
import type { Hex } from '../../types/misc.js'
import { type ConcatErrorType, concat } from '../../utils/data/concat.js'
import { type PadErrorType, pad } from '../../utils/data/pad.js'
import { type ToHexErrorType, toHex } from '../../utils/encoding/toHex.js'
import {
  type Keccak256ErrorType,
  keccak256,
} from '../../utils/hash/keccak256.js'

export type GetSourceHashParameters = {
  /** The L1 block hash. */
  l1BlockHash: Hex
} & (
  | {
      /** Domain of source hash. */
      domain: 'userDeposit'
      /** The index of the log on the L1. */
      l1LogIndex: number
      /** The sequence number. */
      sequenceNumber?: undefined
    }
  | {
      /** Domain of source hash. */
      domain: 'l1InfoDeposit'
      /** The index of the log on the L1. */
      l1LogIndex?: undefined
      /** The sequence number. */
      sequenceNumber: number
    }
)

export type GetSourceHashReturnType = Hex

export type GetSourceHashErrorType =
  | ConcatErrorType
  | Keccak256ErrorType
  | PadErrorType
  | ToHexErrorType
  | ErrorType

const sourceHashDomainMap = {
  userDeposit: 0,
  l1InfoDeposit: 1,
} as const

export function getSourceHash({
  domain,
  l1LogIndex,
  l1BlockHash,
  sequenceNumber,
}: GetSourceHashParameters) {
  const marker = toHex(l1LogIndex! ?? sequenceNumber!)
  const input = concat([l1BlockHash, pad(marker, { size: 32 })])
  const depositIdHash = keccak256(input)
  const domainHex = toHex(sourceHashDomainMap[domain])
  const domainInput = concat([pad(domainHex, { size: 32 }), depositIdHash])
  return keccak256(domainInput)
}