Struct ethcore::engines::NullEngine

pub struct NullEngine<M> { /* fields omitted */ }

An engine which does not provide any consensus mechanism and does not seal blocks.

Methods

impl<M> NullEngine<M>

pub fn new(params: NullEngineParams, machine: M) -> Self

Returns new instance of NullEngine with default VM Factory

Trait Implementations

impl<M: Default> Default for NullEngine<M>

fn default() -> Self

Returns the "default value" for a type.

impl<M: WithBalances + WithRewards> Engine<M> for NullEngine<M> where     M::ExtendedHeader: TotalScoredHeader,     <M::ExtendedHeader as TotalScoredHeader>::Value: Ord,

fn name(&self) -> &str

The name of this engine.

Important traits for &'a mut R

impl<'a, R> Read for &'a mut R where
    R: Read + ?Sized, impl<'a, W> Write for &'a mut W where
    W: Write + ?Sized, impl<'a, I> Iterator for &'a mut I where
    I: Iterator + ?Sized,  type Item = <I as Iterator>::Item;

fn machine(&self) -> &M

Get access to the underlying state machine.

fn on_close_block(&self, block: &mut M::LiveBlock) -> Result<(), M::Error>

Block transformation functions, after the transactions.

fn maximum_uncle_count(&self, _block: BlockNumber) -> usize

Maximum number of uncles a block is allowed to declare.

fn verify_local_seal(&self, _header: &M::Header) -> Result<(), M::Error>

Verify a locally-generated seal of a header.

fn snapshot_components(&self) -> Option<Box<SnapshotComponents>>

Create a factory for building snapshot chunks and restoring from them. Returning None indicates that this engine doesn't support snapshot creation.

fn fork_choice(     &self,     new: &M::ExtendedHeader,     current: &M::ExtendedHeader ) -> ForkChoice

Check whether the given new block is the best block, after finalization check.

fn seal_fields(&self, _header: &M::Header) -> usize

The number of additional header fields required for this engine.

fn extra_info(&self, _header: &M::Header) -> BTreeMap<String, String>

Additional engine-specific information for the user/developer concerning header.

fn maximum_uncle_age(&self) -> usize

The number of generations back that uncles can be.

fn on_new_block(     &self,     _block: &mut M::LiveBlock,     _epoch_begin: bool,     _ancestry: &mut Iterator<Item = M::ExtendedHeader> ) -> Result<(), M::Error>

Block transformation functions, before the transactions. epoch_begin set to true if this block kicks off an epoch.

fn seals_internally(&self) -> Option<bool>

None means that it requires external input (e.g. PoW) to seal a block. Some(true) means the engine is currently prime for seal generation (i.e. node is the current validator). Some(false) means that the node might seal internally but is not qualified now.

fn generate_seal(&self, _block: &M::LiveBlock, _parent: &M::Header) -> Seal

Attempt to seal the block internally.

fn verify_block_basic(&self, _header: &M::Header) -> Result<(), M::Error>

Phase 1 quick block verification. Only does checks that are cheap. Returns either a null Ok or a general error detailing the problem with import.

fn verify_block_unordered(&self, _header: &M::Header) -> Result<(), M::Error>

Phase 2 verification. Perform costly checks such as transaction signatures. Returns either a null Ok or a general error detailing the problem with import.

fn verify_block_family(     &self,     _header: &M::Header,     _parent: &M::Header ) -> Result<(), M::Error>

Phase 3 verification. Check block information against parent. Returns either a null Ok or a general error detailing the problem with import.

fn verify_block_external(&self, _header: &M::Header) -> Result<(), M::Error>

Phase 4 verification. Verify block header against potentially external data. Should only be called when register_client has been called previously.

fn genesis_epoch_data<'a>(     &self,     _header: &M::Header,     _state: &<M as Localized<'a>>::StateContext ) -> Result<Vec<u8>, String>

Genesis epoch data.

fn signals_epoch_end<'a>(     &self,     _header: &M::Header,     _aux: <M as Localized<'a>>::AuxiliaryData ) -> EpochChange<M>

Whether an epoch change is signalled at the given header but will require finality. If a change can be enacted immediately then return No from this function but Yes from is_epoch_end.

fn is_epoch_end(     &self,     _chain_head: &M::Header,     _chain: &Headers<M::Header>,     _transition_store: &PendingTransitionStore ) -> Option<Vec<u8>>

Whether a block is the end of an epoch.

fn epoch_verifier<'a>(     &self,     _header: &M::Header,     _proof: &'a [u8] ) -> ConstructedVerifier<'a, M>

Create an epoch verifier from validation proof and a flag indicating whether finality is required.

fn populate_from_parent(&self, _header: &mut M::Header, _parent: &M::Header)

Populate a header's fields based on its parent's header. Usually implements the chain scoring rule based on weight.

fn handle_message(&self, _message: &[u8]) -> Result<(), EngineError>

Handle any potential consensus messages; updating consensus state and potentially issuing a new one.

fn is_proposal(&self, _verified_header: &M::Header) -> bool

Find out if the block is a proposal block and should not be inserted into the DB. Takes a header of a fully verified block.

fn set_signer(     &self,     _account_provider: Arc<AccountProvider>,     _address: Address,     _password: String )

Register an account which signs consensus messages.

fn sign(&self, _hash: H256) -> Result<Signature, M::Error>

Sign using the EngineSigner, to be used for consensus tx signing.

fn register_client(&self, _client: Weak<M::EngineClient>)

Add Client which can be used for sealing, potentially querying the state and sending messages.

fn step(&self)

Trigger next step of the consensus engine.

fn stop(&self)

Stops any services that the may hold the Engine and makes it safe to drop.

fn supports_warp(&self) -> bool

Whether this engine supports warp sync.

fn open_block_header_timestamp(&self, parent_timestamp: u64) -> u64

Return a new open block header timestamp based on the parent timestamp.

fn is_timestamp_valid(     &self,     header_timestamp: u64,     parent_timestamp: u64 ) -> bool

Check whether the parent timestamp is valid.

Important traits for Vec<u8>

impl Write for Vec<u8>

fn ancestry_actions(     &self,     _block: &M::LiveBlock,     _ancestry: &mut Iterator<Item = M::ExtendedHeader> ) -> Vec<AncestryAction>

Gather all ancestry actions. Called at the last stage when a block is committed. The Engine must guarantee that the ancestry exists.