openethereum/ethcore/src/engine.rs
2016-02-02 23:43:29 +01:00

80 lines
4.3 KiB
Rust

use common::*;
use block::ExecutedBlock;
use spec::Spec;
use evm::Schedule;
use evm::Factory;
/// A consensus mechanism for the chain. Generally either proof-of-work or proof-of-stake-based.
/// Provides hooks into each of the major parts of block import.
pub trait Engine : Sync + Send {
/// The name of this engine.
fn name(&self) -> &str;
/// The version of this engine. Should be of the form
fn version(&self) -> SemanticVersion { SemanticVersion::new(0, 0, 0) }
/// The number of additional header fields required for this engine.
fn seal_fields(&self) -> usize { 0 }
/// Default values of the additional fields RLP-encoded in a raw (non-list) harness.
fn seal_rlp(&self) -> Bytes { vec![] }
/// Additional engine-specific information for the user/developer concerning `header`.
fn extra_info(&self, _header: &Header) -> HashMap<String, String> { HashMap::new() }
/// Get the general parameters of the chain.
fn spec(&self) -> &Spec;
/// Get current EVM factory
fn vm_factory(&self) -> &Factory;
/// Get the EVM schedule for the given `env_info`.
fn schedule(&self, env_info: &EnvInfo) -> Schedule;
/// Some intrinsic operation parameters; by default they take their value from the `spec()`'s `engine_params`.
fn maximum_extra_data_size(&self) -> usize { decode(&self.spec().engine_params.get("maximumExtraDataSize").unwrap()) }
/// Maximum number of uncles a block is allowed to declare.
fn maximum_uncle_count(&self) -> usize { 2 }
/// The nonce with which accounts begin.
fn account_start_nonce(&self) -> U256 { decode(&self.spec().engine_params.get("accountStartNonce").unwrap()) }
/// Block transformation functions, before the transactions.
fn on_new_block(&self, _block: &mut ExecutedBlock) {}
/// Block transformation functions, after the transactions.
fn on_close_block(&self, _block: &mut ExecutedBlock) {}
/// Phase 1 quick block verification. Only does checks that are cheap. `block` (the header's full block)
/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
fn verify_block_basic(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
/// Phase 2 verification. Perform costly checks such as transaction signatures. `block` (the header's full block)
/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
fn verify_block_unordered(&self, _header: &Header, _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
/// Phase 3 verification. Check block information against parent and uncles. `block` (the header's full block)
/// may be provided for additional checks. Returns either a null `Ok` or a general error detailing the problem with import.
fn verify_block_family(&self, _header: &Header, _parent: &Header, _block: Option<&[u8]>) -> Result<(), Error> { Ok(()) }
/// Additional verification for transactions in blocks.
// TODO: Add flags for which bits of the transaction to check.
// TODO: consider including State in the params.
fn verify_transaction_basic(&self, _t: &Transaction, _header: &Header) -> Result<(), Error> { Ok(()) }
/// Verify a particular transaction is valid.
fn verify_transaction(&self, _t: &Transaction, _header: &Header) -> Result<(), Error> { Ok(()) }
/// Don't forget to call Super::populateFromParent when subclassing & overriding.
// TODO: consider including State in the params.
fn populate_from_parent(&self, _header: &mut Header, _parent: &Header) {}
// TODO: builtin contract routing - to do this properly, it will require removing the built-in configuration-reading logic
// from Spec into here and removing the Spec::builtins field.
/// Determine whether a particular address is a builtin contract.
fn is_builtin(&self, a: &Address) -> bool { self.spec().builtins.contains_key(a) }
/// Determine the code execution cost of the builtin contract with address `a`.
/// Panics if `is_builtin(a)` is not true.
fn cost_of_builtin(&self, a: &Address, input: &[u8]) -> U256 { self.spec().builtins.get(a).unwrap().cost(input.len()) }
/// Execution the builtin contract `a` on `input` and return `output`.
/// Panics if `is_builtin(a)` is not true.
fn execute_builtin(&self, a: &Address, input: &[u8], output: &mut [u8]) { self.spec().builtins.get(a).unwrap().execute(input, output); }
// TODO: sealing stuff - though might want to leave this for later.
}