Struct evm_adapters::sputnik::cache::SharedBackend

pub struct SharedBackend { /* fields omitted */ }

A cloneable backend type that shares access to the backend data with all its clones.

This backend type is connected to the BackendHandler via a mpsc channel. The BackendHandlers is spawned on a background thread and listens for incoming commands on the receiver half of the channel. A SharedBackend holds a sender for that channel, which is Clone, so their can be multiple SharedBackends communicating with the same BackendHandler, hence this Backend type is thread safe.

All Backend trait functions are delegated as a BackendRequest via the channel to the BackendHandler. All BackendRequest variants include a sender half of an additional channel that is used by the BackendHandler to send the result of an executed BackendRequest back to SharedBackend.

The BackendHandler holds an ethers Provider to look up missing accounts or storage slots from remote (e.g. infura). It detects duplicate requests from multiple SharedBackends and bundles them together, so that always only one provider request is executed. For example, there are two SharedBackends, A and B, both request the basic account info of account 0xasd9sa7d... at the same time. After the BackendHandler receives the request from A, it sends a new provider request to the provider’s endpoint, then it reads the identical request from B and simply adds it as an additional listener for the request already in progress, instead of sending another one. So that after the provider returns the response all listeners (A and B) get notified.

Implementations

impl SharedBackend

pub fn new<M>(
    provider: M,
    cache: SharedCache<MemCache>,
    vicinity: MemoryVicinity,
    pin_block: Option<BlockId>
) -> Self where
    M: Middleware + Unpin + 'static + Clone, 

Spawns a new BackendHandler on a background thread that listens for requests from any SharedBackend. Missing values get inserted in the cache.

NOTE: this should be called with Arc<Provider>

Trait Implementations

impl Backend for SharedBackend

fn gas_price(&self) -> U256

Gas price. Unused for London.

fn origin(&self) -> H160

Origin.

fn block_hash(&self, number: U256) -> H256

Environmental block hash.

fn block_number(&self) -> U256

Environmental block number.

fn block_coinbase(&self) -> H160

Environmental coinbase.

fn block_timestamp(&self) -> U256

Environmental block timestamp.

fn block_difficulty(&self) -> U256

Environmental block difficulty.

fn block_gas_limit(&self) -> U256

Environmental block gas limit.

fn block_base_fee_per_gas(&self) -> U256

Environmental block base fee.

fn chain_id(&self) -> U256

Environmental chain ID.

fn exists(&self, address: H160) -> bool

Whether account at address exists.

fn basic(&self, address: H160) -> Basic

Get basic account information.

fn code(&self, address: H160) -> Vec<u8>

Get account code.

fn storage(&self, address: H160, index: TxHash) -> TxHash

Get storage value of address at index.

fn original_storage(&self, address: H160, index: TxHash) -> Option<TxHash>

Get original storage value of address at index, if available.

impl Clone for SharedBackend

fn clone(&self) -> SharedBackend

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for SharedBackend

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.