VM: stateManager -> add modifyAccountFields method

packages/vm/src/state/interface.ts

@@ -8,12 +8,15 @@ export interface StorageDump {
   [key: string]: string
 }
 
+export type AccountFields = Partial<Pick<Account, 'nonce' | 'balance' | 'stateRoot' | 'codeHash'>>
+
 export interface StateManager {
   copy(): StateManager
   getAccount(address: Address): Promise<Account>
   putAccount(address: Address, account: Account): Promise<void>
   deleteAccount(address: Address): Promise<void>
   touchAccount(address: Address): void
+  modifyAccountFields(address: Address, accountFields: AccountFields): Promise<void>
   putContractCode(address: Address, value: Buffer): Promise<void>
   getContractCode(address: Address): Promise<Buffer>
   getContractStorage(address: Address, key: Buffer): Promise<Buffer>

packages/vm/src/state/stateManager.ts

@@ -13,7 +13,7 @@ import {
 import { encode, decode } from 'rlp'
 import Common, { Chain, Hardfork } from '@ethereumjs/common'
 import { genesisStateByName } from '@ethereumjs/common/dist/genesisStates'
-import { StateManager, StorageDump } from './interface'
+import { AccountFields, StateManager, StorageDump } from './interface'
 import Cache from './cache'
 import { getActivePrecompiles, ripemdPrecompileAddress } from '../evm/precompiles'
 import { short } from '../evm/opcodes'
@@ -157,11 +157,28 @@ export default class DefaultStateManager implements StateManager {
    * This happens when the account is triggered for a state-changing
    * event. Touched accounts that are empty will be cleared
    * at the end of the tx.
+   * @param address - Address of the account to touch
    */
   touchAccount(address: Address): void {
     this._touched.add(address.buf.toString('hex'))
   }
 
+  /**
+   * Gets the account associated with `address`, modifies the given account
+   * fields, then saves the account into state. Account fields can include
+   * `nonce`, `balance`, `stateRoot`, and `codeHash`.
+   * @param address - Address of the account to modify
+   * @param accountFields - Object containing account fields and values to modify
+   */
+  async modifyAccountFields(address: Address, accountFields: AccountFields): Promise<void> {
+    const account = await this.getAccount(address)
+    account.nonce = accountFields.nonce ?? account.nonce
+    account.balance = accountFields.balance ?? account.balance
+    account.stateRoot = accountFields.stateRoot ?? account.stateRoot
+    account.codeHash = accountFields.codeHash ?? account.codeHash
+    await this.putAccount(address, account)
+  }
+
   /**
    * Adds `value` to the state trie as code, and sets `codeHash` on the account
    * corresponding to `address` to reference this.

packages/vm/tests/api/state/stateManager.spec.ts

@@ -168,6 +168,29 @@ tape('StateManager', (t) => {
       st.end()
     }
   )
+
+  t.test('should modify account fields correctly', async (st) => {
+    const stateManager = new DefaultStateManager()
+    const account = createAccount()
+    const address = new Address(Buffer.from('a94f5374fce5edbc8e2a8697c15331677e6ebf0b', 'hex'))
+
+    await stateManager.putAccount(address, account)
+
+    await stateManager.modifyAccountFields(address, { balance: new BN(1234) })
+
+    const res1 = await stateManager.getAccount(address)
+
+    st.equal(res1.balance.toString('hex'), '4d2')
+
+    await stateManager.modifyAccountFields(address, { nonce: new BN(1) })
+
+    const res2 = await stateManager.getAccount(address)
+
+    st.equal(res2.nonce.toNumber(), 1)
+
+    st.end()
+  })
+
   t.test(
     'should generate the genesis state root correctly for mainnet from ethereum/tests data',
     async (st) => {