Struct Engine

pub struct Engine {
    pub database: Database,
    pub exec_context: ExecContext,
    pub chain_spec: ChainSpec,
    pub chain_extension_handler: ChainExtensionHandler,
    /* private fields */
}

The off-chain engine.

Fields

database: Database

The environment database.

exec_context: ExecContext

The current execution context.

chain_spec: ChainSpec

The chain specification.

chain_extension_handler: ChainExtensionHandler

Handler for registered chain extensions.

Implementations

impl Engine

pub fn new() -> Self

impl Engine

pub fn transfer(&mut self, dest: H160, value: &[u8]) -> Result<(), Error>

Transfers value from the contract to the destination account.

pub fn deposit_event(&mut self, topics: &[u8], data: &[u8])

Deposits an event identified by the supplied topics and data.

pub fn set_storage(&mut self, key: &[u8], encoded_value: &[u8]) -> Option<u32>

Writes the encoded value into the storage at the given key. Returns the size of the previously stored value at the key if any.

pub fn get_storage(&mut self, key: &[u8]) -> Result<&[u8], Error>

Returns the contract storage bytes at the key if any.

pub fn take_storage(&mut self, key: &[u8]) -> Result<Vec<u8>, Error>

Removes the storage entries at the given key, returning previously stored value at the key if any.

pub fn contains_storage(&mut self, key: &[u8]) -> Option<u32>

Returns the size of the value stored in the contract storage at the key if any.

pub fn clear_storage(&mut self, key: &[u8]) -> Option<u32>

Removes the storage entries at the given key. Returns the size of the previously stored value at the key if any.

pub fn terminate(&mut self, beneficiary: H160) -> !

Remove the calling account and transfer remaining balance.

todo is the following comment still correct? This function never returns. Either the termination was successful and the execution of the destroyed contract is halted. Or it failed during the termination which is considered fatal.

pub fn caller(&self, output: &mut &mut [u8])

Returns the address of the caller.

pub fn balance(&self, output: &mut &mut [u8])

Returns the balance of the executed contract.

pub fn value_transferred(&self, output: &mut &mut [u8])

Returns the transferred value for the called contract.

pub fn address(&self, output: &mut &mut [u8])

Returns the address of the executed contract.

pub fn hash_blake2_256(input: &[u8], output: &mut [u8; 32])

Conduct the BLAKE-2 256-bit hash and place the result into output.

pub fn hash_blake2_128(input: &[u8], output: &mut [u8; 16])

Conduct the BLAKE-2 128-bit hash and place the result into output.

pub fn hash_sha2_256(input: &[u8], output: &mut [u8; 32])

Conduct the SHA-2 256-bit hash and place the result into output.

pub fn hash_keccak_256(input: &[u8], output: &mut [u8; 32])

Conduct the KECCAK 256-bit hash and place the result into output.

pub fn block_number(&self, output: &mut &mut [u8])

Returns the current block number.

pub fn block_timestamp(&self, output: &mut &mut [u8])

Returns the timestamp of the current block.

pub fn minimum_balance(&self, output: &mut &mut [u8])

Returns the minimum balance that is required for creating an account (i.e. the chain’s existential deposit).

pub fn instantiate( &mut self, _code_hash: &[u8], _gas_limit: u64, _endowment: &[u8], _input: &[u8], _out_address: &mut &mut [u8], _out_return_value: &mut &mut [u8], _salt: &[u8], ) -> Result<(), Error>

pub fn call( &mut self, callee: &[u8], _gas_limit: u64, _value: &[u8], input: &[u8], output: &mut &mut [u8], ) -> Result<(), Error>

pub fn weight_to_fee(&self, gas: u64, output: &mut &mut [u8])

Emulates gas price calculation.

pub fn call_chain_extension( &mut self, id: u32, input: &[u8], output: &mut &mut [u8], )

Calls the chain extension method registered at func_id with input.

impl Engine

pub fn ecdsa_recover( &mut self, signature: &[u8; 65], message_hash: &[u8; 32], output: &mut [u8; 33], ) -> Result<(), Error>

Recovers the compressed ECDSA public key for given signature and message_hash, and stores the result in output.

impl Engine

pub fn initialize_or_reset(&mut self)

Resets the environment.

pub fn get_contract_storage_rw(&self, addr: H160) -> (usize, usize)

Returns the total number of reads and writes of the contract’s storage.

pub fn count_reads(&self) -> usize

Returns the total number of reads executed.

pub fn count_writes(&self) -> usize

Returns the total number of writes executed.

pub fn set_caller(&mut self, caller: H160)

Sets a caller for the next call.

pub fn set_contract(&mut self, caller: H160)

Sets a known contract by adding it to a vector of known contracts accounts

pub fn set_callee(&mut self, callee: H160)

Sets the callee for the next call.

pub fn count_used_storage_cells(&self, addr: &H160) -> Result<usize, Error>

Returns the amount of storage cells used by the contract addr.

Returns None if the contract addr is non-existent.

pub fn advance_block(&mut self)

Advances the chain by a single block.

pub fn get_callee(&self) -> H160

Returns the callee, i.e. the currently executing contract.

pub fn is_contract(&self, addr: &H160) -> bool

Returns boolean value indicating whether the account is a contract

pub fn get_emitted_events(&self) -> impl Iterator<Item = EmittedEvent>

Returns the recorded emitted events in order.

pub fn get_acc_balance(&self, addr: AccountId) -> Result<u128, Error>

Returns the current balance of addr.

pub fn set_acc_balance(&mut self, addr: AccountId, new_balance: u128)

Sets the balance of addr to new_balance.

pub fn get_balance(&self, addr: H160) -> Result<U256, Error>

Returns the current balance of addr.

pub fn set_balance(&mut self, addr: H160, new_balance: U256)

Sets the balance of addr to new_balance.

pub fn set_value_transferred(&mut self, value: U256)

Sets the value transferred from the caller to the callee as part of the call.

pub fn set_block_timestamp(&mut self, new_block_timestamp: u64)

Set the block timestamp for the execution context.

pub fn set_block_number(&mut self, new_block_number: u32)

Set the block number for the execution context.

Trait Implementations

impl Default for Engine

fn default() -> Self

Returns the “default value” for a type.