ethereum.forks.paris.stateethereum.forks.shanghai.state
State.
.. contents:: Table of Contents :backlinks: none :local:
Introduction
The state contains all information that is preserved between transactions.
It consists of a main account trie and storage tries for each contract.
There is a distinction between an account that does not exist and
EMPTY_ACCOUNT.
State ¶
Contains all information that is preserved between transactions.
| 38 | @dataclass |
|---|
class State:
_main_trie¶
| 44 | _main_trie: Trie[Address, Optional[Account]] = field( |
|---|---|
| 45 | default_factory=lambda: Trie(secured=True, default=None) |
| 46 | ) |
_storage_tries¶
| 47 | _storage_tries: Dict[Address, Trie[Bytes32, U256]] = field( |
|---|---|
| 48 | default_factory=dict |
| 49 | ) |
_snapshots¶
| 50 | _snapshots: List[ |
|---|---|
| 51 | Tuple[ |
| 52 | Trie[Address, Optional[Account]], |
| 53 | Dict[Address, Trie[Bytes32, U256]], |
| 54 | ] |
| 55 | ] = field(default_factory=list) |
created_accounts¶
| 56 | created_accounts: Set[Address] = field(default_factory=set) |
|---|
_code_store¶
| 57 | _code_store: Dict[Hash32, Bytes] = field( |
|---|---|
| 58 | default_factory=dict, compare=False |
| 59 | ) |
get_code ¶
Return the bytecode for a given code hash.Get the bytecode for a given code hash.
Return b"" for EMPTY_CODE_HASH.
def get_code(self, code_hash: Hash32) -> Bytes:
| 62 | """ |
|---|---|
| 63 | Return the bytecode for a given code hash. |
| 63 | Get the bytecode for a given code hash. |
| 64 | |
| 65 | Return ``b""`` for ``EMPTY_CODE_HASH``. |
| 66 | """ |
| 67 | if code_hash == EMPTY_CODE_HASH: |
| 68 | return b"" |
| 69 | return self._code_store[code_hash] |
close_state ¶
Free resources held by the state. Used by optimized implementations to release file descriptors.
def close_state(state: State) -> None:
| 73 | """ |
|---|---|
| 74 | Free resources held by the state. Used by optimized implementations to |
| 75 | release file descriptors. |
| 76 | """ |
| 77 | del state._main_trie |
| 78 | del state._storage_tries |
| 79 | del state._snapshots |
| 80 | del state.created_accounts |
| 81 | del state._code_store |
begin_transaction ¶
Start a state transaction.
Transactions are entirely implicit and can be nested. It is not possible to calculate the state root during a transaction.
Parameters
state : State The state.
def begin_transaction(state: State) -> None:
| 85 | """ |
|---|---|
| 86 | Start a state transaction. |
| 87 | |
| 88 | Transactions are entirely implicit and can be nested. It is not possible to |
| 89 | calculate the state root during a transaction. |
| 90 | |
| 91 | Parameters |
| 92 | ---------- |
| 93 | state : State |
| 94 | The state. |
| 95 | |
| 96 | """ |
| 97 | state._snapshots.append( |
| 98 | ( |
| 99 | copy_trie(state._main_trie), |
| 100 | {k: copy_trie(t) for (k, t) in state._storage_tries.items()}, |
| 101 | ) |
| 102 | ) |
commit_transaction ¶
Commit a state transaction.
Parameters
state : State The state.
def commit_transaction(state: State) -> None:
| 106 | """ |
|---|---|
| 107 | Commit a state transaction. |
| 108 | |
| 109 | Parameters |
| 110 | ---------- |
| 111 | state : State |
| 112 | The state. |
| 113 | |
| 114 | """ |
| 115 | state._snapshots.pop() |
| 116 | if not state._snapshots: |
| 117 | state.created_accounts.clear() |
rollback_transaction ¶
Rollback a state transaction, resetting the state to the point when the
corresponding begin_transaction() call was made.
Parameters
state : State The state.
def rollback_transaction(state: State) -> None:
| 121 | """ |
|---|---|
| 122 | Rollback a state transaction, resetting the state to the point when the |
| 123 | corresponding `begin_transaction()` call was made. |
| 124 | |
| 125 | Parameters |
| 126 | ---------- |
| 127 | state : State |
| 128 | The state. |
| 129 | |
| 130 | """ |
| 131 | state._main_trie, state._storage_tries = state._snapshots.pop() |
| 132 | if not state._snapshots: |
| 133 | state.created_accounts.clear() |
get_account ¶
Get the Account object at an address. Returns EMPTY_ACCOUNT if there
is no account at the address.
Use get_account_optional() if you care about the difference between a
non-existent account and EMPTY_ACCOUNT.
Parameters
state: State
The state
address : Address
Address to lookup.
Returns
account : Account
Account at address.
def get_account(state: State, address: Address) -> Account:
| 137 | """ |
|---|---|
| 138 | Get the `Account` object at an address. Returns `EMPTY_ACCOUNT` if there |
| 139 | is no account at the address. |
| 140 | |
| 141 | Use `get_account_optional()` if you care about the difference between a |
| 142 | non-existent account and `EMPTY_ACCOUNT`. |
| 143 | |
| 144 | Parameters |
| 145 | ---------- |
| 146 | state: `State` |
| 147 | The state |
| 148 | address : `Address` |
| 149 | Address to lookup. |
| 150 | |
| 151 | Returns |
| 152 | ------- |
| 153 | account : `Account` |
| 154 | Account at address. |
| 155 | |
| 156 | """ |
| 157 | account = get_account_optional(state, address) |
| 158 | if isinstance(account, Account): |
| 159 | return account |
| 160 | else: |
| 161 | return EMPTY_ACCOUNT |
get_account_optional ¶
Get the Account object at an address. Returns None (rather than
EMPTY_ACCOUNT) if there is no account at the address.
Parameters
state: State
The state
address : Address
Address to lookup.
Returns
account : Account
Account at address.
def get_account_optional(state: State, address: Address) -> Optional[Account]:
| 165 | """ |
|---|---|
| 166 | Get the `Account` object at an address. Returns `None` (rather than |
| 167 | `EMPTY_ACCOUNT`) if there is no account at the address. |
| 168 | |
| 169 | Parameters |
| 170 | ---------- |
| 171 | state: `State` |
| 172 | The state |
| 173 | address : `Address` |
| 174 | Address to lookup. |
| 175 | |
| 176 | Returns |
| 177 | ------- |
| 178 | account : `Account` |
| 179 | Account at address. |
| 180 | |
| 181 | """ |
| 182 | account = trie_get(state._main_trie, address) |
| 183 | return account |
get_code ¶
Return the bytecode for a given code hash.Get the bytecode for a given code hash.
Parameters
state:
The current state.
code_hash:
The hash of the code to retrieve.Return b"" for EMPTY_CODE_HASH.
Returns
code : Bytes
The bytecode for the given hash.
def get_code(state: State, code_hash: Hash32) -> Bytes:
| 187 | """ |
|---|---|
| 186 | Return the bytecode for a given code hash. |
| 188 | Get the bytecode for a given code hash. |
| 189 | |
| 188 | Parameters |
| 189 | ---------- |
| 190 | state: |
| 191 | The current state. |
| 192 | code_hash: |
| 193 | The hash of the code to retrieve. |
| 194 | |
| 195 | Returns |
| 196 | ------- |
| 197 | code : `Bytes` |
| 198 | The bytecode for the given hash. |
| 199 | |
| 190 | Return ``b""`` for ``EMPTY_CODE_HASH``. |
| 191 | """ |
| 201 | return state.get_code(code_hash) |
| 192 | if code_hash == EMPTY_CODE_HASH: |
| 193 | return b"" |
| 194 | return state._code_store[code_hash] |
store_code ¶
Store bytecode in the code store and return its hash.Store bytecode in State and return its hash.
Parameters
state: The current state. code: The bytecode to store.
Returns
code_hash : Hash32
The keccak256 hash of the stored bytecode.
def store_code(state: State, code: Bytes) -> Hash32:
| 198 | """ |
|---|---|
| 206 | Store bytecode in the code store and return its hash. |
| 207 | |
| 208 | Parameters |
| 209 | ---------- |
| 210 | state: |
| 211 | The current state. |
| 212 | code: |
| 213 | The bytecode to store. |
| 214 | |
| 215 | Returns |
| 216 | ------- |
| 217 | code_hash : `Hash32` |
| 218 | The keccak256 hash of the stored bytecode. |
| 219 | |
| 199 | Store bytecode in ``State`` and return its hash. |
| 200 | """ |
| 201 | code_hash = keccak256(code) |
| 202 | if code_hash != EMPTY_CODE_HASH: |
| 203 | state._code_store[code_hash] = code |
| 204 | return code_hash |
set_account ¶
Set the Account object at an address. Setting to None deletes
the account (but not its storage, see destroy_account()).
Parameters
state: State
The state
address : Address
Address to set.
account : Account
Account to set at address.
def set_account(state: State, address: Address, account: Optional[Account]) -> None:
| 210 | """ |
|---|---|
| 211 | Set the `Account` object at an address. Setting to `None` deletes |
| 212 | the account (but not its storage, see `destroy_account()`). |
| 213 | |
| 214 | Parameters |
| 215 | ---------- |
| 216 | state: `State` |
| 217 | The state |
| 218 | address : `Address` |
| 219 | Address to set. |
| 220 | account : `Account` |
| 221 | Account to set at address. |
| 222 | |
| 223 | """ |
| 224 | trie_set(state._main_trie, address, account) |
destroy_account ¶
Completely remove the account at address and all of its storage.
This function is made available exclusively for the SELFDESTRUCT
opcode. It is expected that SELFDESTRUCT will be disabled in a future
hardfork and this function will be removed.
Parameters
state: State
The state
address : Address
Address of account to destroy.
def destroy_account(state: State, address: Address) -> None:
| 228 | """ |
|---|---|
| 229 | Completely remove the account at `address` and all of its storage. |
| 230 | |
| 231 | This function is made available exclusively for the `SELFDESTRUCT` |
| 232 | opcode. It is expected that `SELFDESTRUCT` will be disabled in a future |
| 233 | hardfork and this function will be removed. |
| 234 | |
| 235 | Parameters |
| 236 | ---------- |
| 237 | state: `State` |
| 238 | The state |
| 239 | address : `Address` |
| 240 | Address of account to destroy. |
| 241 | |
| 242 | """ |
| 243 | destroy_storage(state, address) |
| 244 | set_account(state, address, None) |
destroy_storage ¶
Completely remove the storage at address.
Parameters
state: State
The state
address : Address
Address of account whose storage is to be deleted.
def destroy_storage(state: State, address: Address) -> None:
| 248 | """ |
|---|---|
| 249 | Completely remove the storage at `address`. |
| 250 | |
| 251 | Parameters |
| 252 | ---------- |
| 253 | state: `State` |
| 254 | The state |
| 255 | address : `Address` |
| 256 | Address of account whose storage is to be deleted. |
| 257 | |
| 258 | """ |
| 259 | if address in state._storage_tries: |
| 260 | del state._storage_tries[address] |
mark_account_created ¶
Mark an account as having been created in the current transaction.
This information is used by get_storage_original() to handle an obscure
edgecase.
The marker is not removed even if the account creation reverts. Since the
account cannot have had code prior to its creation and can't call
get_storage_original(), this is harmless.
Parameters
state: State
The state
address : Address
Address of the account that has been created.
def mark_account_created(state: State, address: Address) -> None:
| 264 | """ |
|---|---|
| 265 | Mark an account as having been created in the current transaction. |
| 266 | This information is used by `get_storage_original()` to handle an obscure |
| 267 | edgecase. |
| 268 | |
| 269 | The marker is not removed even if the account creation reverts. Since the |
| 270 | account cannot have had code prior to its creation and can't call |
| 271 | `get_storage_original()`, this is harmless. |
| 272 | |
| 273 | Parameters |
| 274 | ---------- |
| 275 | state: `State` |
| 276 | The state |
| 277 | address : `Address` |
| 278 | Address of the account that has been created. |
| 279 | |
| 280 | """ |
| 281 | state.created_accounts.add(address) |
get_storage ¶
Get a value at a storage key on an account. Returns U256(0) if the
storage key has not been set previously.
Parameters
state: State
The state
address : Address
Address of the account.
key : Bytes
Key to lookup.
Returns
value : U256
Value at the key.
def get_storage(state: State, address: Address, key: Bytes32) -> U256:
| 285 | """ |
|---|---|
| 286 | Get a value at a storage key on an account. Returns `U256(0)` if the |
| 287 | storage key has not been set previously. |
| 288 | |
| 289 | Parameters |
| 290 | ---------- |
| 291 | state: `State` |
| 292 | The state |
| 293 | address : `Address` |
| 294 | Address of the account. |
| 295 | key : `Bytes` |
| 296 | Key to lookup. |
| 297 | |
| 298 | Returns |
| 299 | ------- |
| 300 | value : `U256` |
| 301 | Value at the key. |
| 302 | |
| 303 | """ |
| 304 | trie = state._storage_tries.get(address) |
| 305 | if trie is None: |
| 306 | return U256(0) |
| 307 | |
| 308 | value = trie_get(trie, key) |
| 309 | |
| 310 | assert isinstance(value, U256) |
| 311 | return value |
set_storage ¶
Set a value at a storage key on an account. Setting to U256(0) deletes
the key.
Parameters
state: State
The state
address : Address
Address of the account.
key : Bytes
Key to set.
value : U256
Value to set at the key.
def set_storage(state: State, address: Address, key: Bytes32, value: U256) -> None:
| 317 | """ |
|---|---|
| 318 | Set a value at a storage key on an account. Setting to `U256(0)` deletes |
| 319 | the key. |
| 320 | |
| 321 | Parameters |
| 322 | ---------- |
| 323 | state: `State` |
| 324 | The state |
| 325 | address : `Address` |
| 326 | Address of the account. |
| 327 | key : `Bytes` |
| 328 | Key to set. |
| 329 | value : `U256` |
| 330 | Value to set at the key. |
| 331 | |
| 332 | """ |
| 333 | assert trie_get(state._main_trie, address) is not None |
| 334 | |
| 335 | trie = state._storage_tries.get(address) |
| 336 | if trie is None: |
| 337 | trie = Trie(secured=True, default=U256(0)) |
| 338 | state._storage_tries[address] = trie |
| 339 | trie_set(trie, key, value) |
| 340 | if trie._data == {}: |
| 341 | del state._storage_tries[address] |
storage_root ¶
Calculate the storage root of an account.
Parameters
state: The state address : Address of the account.
Returns
root : Root
Storage root of the account.
def storage_root(state: State, address: Address) -> Root:
| 345 | """ |
|---|---|
| 346 | Calculate the storage root of an account. |
| 347 | |
| 348 | Parameters |
| 349 | ---------- |
| 350 | state: |
| 351 | The state |
| 352 | address : |
| 353 | Address of the account. |
| 354 | |
| 355 | Returns |
| 356 | ------- |
| 357 | root : `Root` |
| 358 | Storage root of the account. |
| 359 | |
| 360 | """ |
| 361 | assert not state._snapshots |
| 362 | if address in state._storage_tries: |
| 363 | return root(state._storage_tries[address]) |
| 364 | else: |
| 365 | return EMPTY_TRIE_ROOT |
state_root ¶
Calculate the state root.
Parameters
state: The current state.
Returns
root : Root
The state root.
def state_root(state: State) -> Root:
| 369 | """ |
|---|---|
| 370 | Calculate the state root. |
| 371 | |
| 372 | Parameters |
| 373 | ---------- |
| 374 | state: |
| 375 | The current state. |
| 376 | |
| 377 | Returns |
| 378 | ------- |
| 379 | root : `Root` |
| 380 | The state root. |
| 381 | |
| 382 | """ |
| 383 | assert not state._snapshots |
| 384 | |
| 385 | def get_storage_root(address: Address) -> Root: |
| 386 | return storage_root(state, address) |
| 387 | |
| 388 | return root(state._main_trie, get_storage_root=get_storage_root) |
account_exists ¶
Checks if an account exists in the state trie.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
account_exists : bool
True if account exists in the state trie, False otherwise
def account_exists(state: State, address: Address) -> bool:
| 392 | """ |
|---|---|
| 393 | Checks if an account exists in the state trie. |
| 394 | |
| 395 | Parameters |
| 396 | ---------- |
| 397 | state: |
| 398 | The state |
| 399 | address: |
| 400 | Address of the account that needs to be checked. |
| 401 | |
| 402 | Returns |
| 403 | ------- |
| 404 | account_exists : `bool` |
| 405 | True if account exists in the state trie, False otherwise |
| 406 | |
| 407 | """ |
| 408 | return get_account_optional(state, address) is not None |
account_has_code_or_nonce ¶
Checks if an account has non-zero nonce or non-empty code.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
has_code_or_nonce : bool
True if the account has non-zero nonce or non-empty code,
False otherwise.
def account_has_code_or_nonce(state: State, address: Address) -> bool:
| 412 | """ |
|---|---|
| 413 | Checks if an account has non-zero nonce or non-empty code. |
| 414 | |
| 415 | Parameters |
| 416 | ---------- |
| 417 | state: |
| 418 | The state |
| 419 | address: |
| 420 | Address of the account that needs to be checked. |
| 421 | |
| 422 | Returns |
| 423 | ------- |
| 424 | has_code_or_nonce : `bool` |
| 425 | True if the account has non-zero nonce or non-empty code, |
| 426 | False otherwise. |
| 427 | |
| 428 | """ |
| 429 | account = get_account(state, address) |
| 430 | return account.nonce != Uint(0) or account.code_hash != EMPTY_CODE_HASH |
account_has_storage ¶
Checks if an account has storage.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
has_storage : bool
True if the account has storage, False otherwise.
def account_has_storage(state: State, address: Address) -> bool:
| 434 | """ |
|---|---|
| 435 | Checks if an account has storage. |
| 436 | |
| 437 | Parameters |
| 438 | ---------- |
| 439 | state: |
| 440 | The state |
| 441 | address: |
| 442 | Address of the account that needs to be checked. |
| 443 | |
| 444 | Returns |
| 445 | ------- |
| 446 | has_storage : `bool` |
| 447 | True if the account has storage, False otherwise. |
| 448 | |
| 449 | """ |
| 450 | return address in state._storage_tries |
is_account_alive ¶
Check whether an account is both in the state and non-empty.
Parameters
state: The state address: Address of the account that needs to be checked.
Returns
is_alive : bool
True if the account is alive.
def is_account_alive(state: State, address: Address) -> bool:
| 454 | """ |
|---|---|
| 455 | Check whether an account is both in the state and non-empty. |
| 456 | |
| 457 | Parameters |
| 458 | ---------- |
| 459 | state: |
| 460 | The state |
| 461 | address: |
| 462 | Address of the account that needs to be checked. |
| 463 | |
| 464 | Returns |
| 465 | ------- |
| 466 | is_alive : `bool` |
| 467 | True if the account is alive. |
| 468 | |
| 469 | """ |
| 470 | account = get_account_optional(state, address) |
| 471 | return account is not None and account != EMPTY_ACCOUNT |
modify_state ¶
Modify an Account in the State. If, after modification, the account
exists and has zero nonce, empty code, and zero balance, it is destroyed.
def modify_state(state: State, address: Address, f: Callable[[Account], None]) -> None:
| 477 | """ |
|---|---|
| 478 | Modify an `Account` in the `State`. If, after modification, the account |
| 479 | exists and has zero nonce, empty code, and zero balance, it is destroyed. |
| 480 | """ |
| 481 | set_account(state, address, modify(get_account(state, address), f)) |
| 482 | |
| 483 | account = get_account_optional(state, address) |
| 484 | account_exists_and_is_empty = ( |
| 485 | account is not None |
| 486 | and account.nonce == Uint(0) |
| 487 | and account.code_hash == EMPTY_CODE_HASH |
| 488 | and account.balance == 0 |
| 489 | ) |
| 490 | |
| 491 | if account_exists_and_is_empty: |
| 492 | destroy_account(state, address) |
move_ether ¶
Move funds between accounts.
def move_ether(state: State, sender_address: Address, recipient_address: Address, amount: U256) -> None:
| 501 | """ |
|---|---|
| 502 | Move funds between accounts. |
| 503 | """ |
| 504 | |
| 505 | def reduce_sender_balance(sender: Account) -> None: |
| 506 | if sender.balance < amount: |
| 507 | raise AssertionError |
| 508 | sender.balance -= amount |
| 509 | |
| 510 | def increase_recipient_balance(recipient: Account) -> None: |
| 511 | recipient.balance += amount |
| 512 | |
| 513 | modify_state(state, sender_address, reduce_sender_balance) |
| 514 | modify_state(state, recipient_address, increase_recipient_balance) |
set_account_balance ¶
Sets the balance of an account.
Parameters
state: The current state.
address: Address of the account whose nonce needs to be incremented.
amount: The amount that needs to be set in the balance.
def set_account_balance(state: State, address: Address, amount: U256) -> None:
| 518 | """ |
|---|---|
| 519 | Sets the balance of an account. |
| 520 | |
| 521 | Parameters |
| 522 | ---------- |
| 523 | state: |
| 524 | The current state. |
| 525 | |
| 526 | address: |
| 527 | Address of the account whose nonce needs to be incremented. |
| 528 | |
| 529 | amount: |
| 530 | The amount that needs to be set in the balance. |
| 531 | |
| 532 | """ |
| 533 | |
| 534 | def set_balance(account: Account) -> None: |
| 535 | account.balance = amount |
| 536 | |
| 537 | modify_state(state, address, set_balance) |
increment_nonce ¶
Increments the nonce of an account.
Parameters
state: The current state.
address: Address of the account whose nonce needs to be incremented.
def increment_nonce(state: State, address: Address) -> None:
| 541 | """ |
|---|---|
| 542 | Increments the nonce of an account. |
| 543 | |
| 544 | Parameters |
| 545 | ---------- |
| 546 | state: |
| 547 | The current state. |
| 548 | |
| 549 | address: |
| 550 | Address of the account whose nonce needs to be incremented. |
| 551 | |
| 552 | """ |
| 553 | |
| 554 | def increase_nonce(sender: Account) -> None: |
| 555 | sender.nonce += Uint(1) |
| 556 | |
| 557 | modify_state(state, address, increase_nonce) |
set_code ¶
Sets Account code.
Parameters
state: The current state.
address: Address of the account whose code needs to be updated.
code: The bytecode that needs to be set.
def set_code(state: State, address: Address, code: Bytes) -> None:
| 561 | """ |
|---|---|
| 562 | Sets Account code. |
| 563 | |
| 564 | Parameters |
| 565 | ---------- |
| 566 | state: |
| 567 | The current state. |
| 568 | |
| 569 | address: |
| 570 | Address of the account whose code needs to be updated. |
| 571 | |
| 572 | code: |
| 573 | The bytecode that needs to be set. |
| 574 | |
| 575 | """ |
| 576 | code_hash = store_code(state, code) |
| 577 | |
| 578 | def write_code(sender: Account) -> None: |
| 579 | sender.code_hash = code_hash |
| 580 | |
| 581 | modify_state(state, address, write_code) |
get_storage_original ¶
Get the original value in a storage slot i.e. the value before the current transaction began. This function reads the value from the snapshots taken before executing the transaction.
Parameters
state: The current state. address: Address of the account to read the value from. key: Key of the storage slot.
def get_storage_original(state: State, address: Address, key: Bytes32) -> U256:
| 585 | """ |
|---|---|
| 586 | Get the original value in a storage slot i.e. the value before the current |
| 587 | transaction began. This function reads the value from the snapshots taken |
| 588 | before executing the transaction. |
| 589 | |
| 590 | Parameters |
| 591 | ---------- |
| 592 | state: |
| 593 | The current state. |
| 594 | address: |
| 595 | Address of the account to read the value from. |
| 596 | key: |
| 597 | Key of the storage slot. |
| 598 | |
| 599 | """ |
| 600 | # In the transaction where an account is created, its preexisting storage |
| 601 | # is ignored. |
| 602 | if address in state.created_accounts: |
| 603 | return U256(0) |
| 604 | |
| 605 | _, original_trie = state._snapshots[0] |
| 606 | original_account_trie = original_trie.get(address) |
| 607 | |
| 608 | if original_account_trie is None: |
| 609 | original_value = U256(0) |
| 610 | else: |
| 611 | original_value = trie_get(original_account_trie, key) |
| 612 | |
| 613 | assert isinstance(original_value, U256) |
| 614 | |
| 615 | return original_value |