ethereum.state

Shared state types and the PreState protocol used by the state transition function.

The PreState protocol specifies the operations that any pre-execution state provider must support, allowing multiple backing implementations (in-memory dict, on-disk database, witness, etc.).

Address

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Address = Bytes20

Root

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Root = Hash32

Account

State associated with an address.

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@slotted_freezable
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@dataclass
class Account:

nonce

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    nonce: Uint

balance

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    balance: U256

code

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    code: Bytes

EMPTY_ACCOUNT

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EMPTY_ACCOUNT = Account(
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    nonce=Uint(0),
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    balance=U256(0),
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    code=b"",
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)

LeafNode

Leaf node in the Merkle Trie.

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@slotted_freezable
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@dataclass
class LeafNode:

rest_of_key

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    rest_of_key: Bytes

value

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    value: Extended

ExtensionNode

Extension node in the Merkle Trie.

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@slotted_freezable
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@dataclass
class ExtensionNode:

key_segment

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    key_segment: Bytes

subnode

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    subnode: Extended

BranchSubnodes

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BranchSubnodes = Tuple[
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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    Extended,
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]

BranchNode

Branch node in the Merkle Trie.

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@slotted_freezable
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@dataclass
class BranchNode:

subnodes

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    subnodes: BranchSubnodes

value

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    value: Extended

InternalNode

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InternalNode = LeafNode | ExtensionNode | BranchNode

PreState

Protocol for providing pre-execution state.

Specify the operations that any pre-state provider (dict, database, witness, etc.) must support for the EELS state transition.

class PreState:

get_account_optional

Get the account at an address.

Return None if there is no account at the address.

def get_account_optional(​self, ​​address: Address​) -> Optional[Account]:
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        """
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        Get the account at an address.
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        Return ``None`` if there is no account at the address.
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        """
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        ...

get_storage

Get a storage value.

Return U256(0) if the key has not been set.

def get_storage(​self, ​​address: Address, ​​key: Bytes32​) -> U256:
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        """
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        Get a storage value.
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        Return ``U256(0)`` if the key has not been set.
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        """
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        ...

account_has_storage

Check whether an account has any storage.

Only needed for EIP-7610.

def account_has_storage(​self, ​​address: Address​) -> bool:
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        """
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        Check whether an account has any storage.
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        Only needed for EIP-7610.
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        """
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        ...

compute_state_root_and_trie_changes

Compute the state root after applying changes to the pre-state.

Return the new state root together with the internal trie nodes that were created or modified.

def compute_state_root_and_trie_changes(​self, ​​account_changes: Dict[Address, Optional[Account]], ​​storage_changes: Dict[Address, Dict[Bytes32, U256]]​) -> Tuple[Root, List[InternalNode]]:
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        """
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        Compute the state root after applying changes to the pre-state.
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        Return the new state root together with the internal trie nodes
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        that were created or modified.
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        """
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        ...