ethereum.london.utils.message

  1"""
  2Hardfork Utility Functions For The Message Data-structure
  3^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  4
  5.. contents:: Table of Contents
  6    :backlinks: none
  7    :local:
  8
  9Introduction
 10------------
 11
 12Message specific functions used in this london version of
 13specification.
 14"""
 15from typing import FrozenSet, Optional, Tuple, Union
 16
 17from ethereum.base_types import U256, Bytes, Bytes0, Bytes32, Uint
 18
 19from ..fork_types import Address
 20from ..state import get_account
 21from ..vm import Environment, Message
 22from ..vm.precompiled_contracts.mapping import PRE_COMPILED_CONTRACTS
 23from .address import compute_contract_address
 24
 25
 26def prepare_message(
 27    caller: Address,
 28    target: Union[Bytes0, Address],
 29    value: U256,
 30    data: Bytes,
 31    gas: Uint,
 32    env: Environment,
 33    code_address: Optional[Address] = None,
 34    should_transfer_value: bool = True,
 35    is_static: bool = False,
 36    preaccessed_addresses: FrozenSet[Address] = frozenset(),
 37    preaccessed_storage_keys: FrozenSet[
 38        Tuple[(Address, Bytes32)]
 39    ] = frozenset(),
 40) -> Message:
 41    """
 42    Execute a transaction against the provided environment.
 43
 44    Parameters
 45    ----------
 46    caller :
 47        Address which initiated the transaction
 48    target :
 49        Address whose code will be executed
 50    value :
 51        Value to be transferred.
 52    data :
 53        Array of bytes provided to the code in `target`.
 54    gas :
 55        Gas provided for the code in `target`.
 56    env :
 57        Environment for the Ethereum Virtual Machine.
 58    code_address :
 59        This is usually same as the `target` address except when an alternative
 60        accounts code needs to be executed.
 61        eg. `CALLCODE` calling a precompile.
 62    should_transfer_value :
 63        if True ETH should be transferred while executing a message call.
 64    is_static:
 65        if True then it prevents all state-changing operations from being
 66        executed.
 67    preaccessed_addresses:
 68        Addresses that should be marked as accessed prior to the message call
 69    preaccessed_storage_keys:
 70        Storage keys that should be marked as accessed prior to the message
 71        call
 72
 73    Returns
 74    -------
 75    message: `ethereum.london.vm.Message`
 76        Items containing contract creation or message call specific data.
 77    """
 78    if isinstance(target, Bytes0):
 79        current_target = compute_contract_address(
 80            caller,
 81            get_account(env.state, caller).nonce - U256(1),
 82        )
 83        msg_data = Bytes(b"")
 84        code = data
 85    elif isinstance(target, Address):
 86        current_target = target
 87        msg_data = data
 88        code = get_account(env.state, target).code
 89        if code_address is None:
 90            code_address = target
 91    else:
 92        raise AssertionError("Target must be address or empty bytes")
 93
 94    accessed_addresses = set()
 95    accessed_addresses.add(current_target)
 96    accessed_addresses.add(caller)
 97    accessed_addresses.update(PRE_COMPILED_CONTRACTS.keys())
 98    accessed_addresses.update(preaccessed_addresses)
 99
100    return Message(
101        caller=caller,
102        target=target,
103        gas=gas,
104        value=value,
105        data=msg_data,
106        code=code,
107        depth=Uint(0),
108        current_target=current_target,
109        code_address=code_address,
110        should_transfer_value=should_transfer_value,
111        is_static=is_static,
112        accessed_addresses=accessed_addresses,
113        accessed_storage_keys=set(preaccessed_storage_keys),
114        parent_evm=None,
115    )