Struct casper_execution_engine::core::tracking_copy::TrackingCopy

pub struct TrackingCopy<R> { /* private fields */ }

An interface for the global state that caches all operations (reads and writes) instead of applying them directly to the state. This way the state remains unmodified, while the user can interact with it as if it was being modified in real time.

Implementations

impl<R: StateReader<Key, StoredValue>> TrackingCopy<R>

pub fn new(reader: R) -> TrackingCopy<R>

Creates a new TrackingCopy using the reader as the interface to the state.

pub fn reader(&self) -> &R

Returns the reader used to access the state.

pub fn fork(&self) -> TrackingCopy<&TrackingCopy<R>>

Creates a new TrackingCopy, using this one (including its mutations) as the base state to read against. The intended use case for this function is to “snapshot” the current TrackingCopy and produce a new TrackingCopy where further changes can be made. This allows isolating a specific set of changes (those in the new TrackingCopy) from existing changes. Note that mutations to state caused by new changes (i.e. writes and adds) only impact the new TrackingCopy, not this one. Note that currently there is no join / merge function to bring changes from a fork back to the main TrackingCopy. this means the current usage requires repeated forking, however we recognize this is sub-optimal and will revisit in the future.

pub fn get_keys( &mut self, correlation_id: CorrelationId, key_tag: &KeyTag ) -> Result<BTreeSet<Key>, R::Error>

Gets the set of keys in the state whose tag is key_tag.

pub fn read( &mut self, correlation_id: CorrelationId, key: &Key ) -> Result<Option<StoredValue>, R::Error>

Reads the value stored under key.

pub fn write(&mut self, key: Key, value: StoredValue)

Writes value under key. Note that the write is only cached, and the global state itself remains unmodified.

pub fn add( &mut self, correlation_id: CorrelationId, key: Key, value: StoredValue ) -> Result<AddResult, R::Error>

Ok(None) represents missing key to which we want to “add” some value. Ok(Some(unit)) represents successful operation. Err(error) is reserved for unexpected errors when accessing global state.

pub fn effect(&self) -> ExecutionEffect

Returns the execution effects cached by this instance.

pub fn execution_journal(&self) -> ExecutionJournal

Returns the journal of operations executed on this instance.

pub fn query( &self, correlation_id: CorrelationId, config: &EngineConfig, base_key: Key, path: &[String] ) -> Result<TrackingCopyQueryResult, R::Error>

Calling query() avoids calling into self.cache, so this will not return any values written or mutated in this TrackingCopy via previous calls to write() or add(), since these updates are only held in self.cache.

The intent is that query() is only used to satisfy QueryRequests made to the server. Other EE internal use cases should call read() or get() in order to retrieve cached values.

Trait Implementations

impl<R: StateReader<Key, StoredValue>> StateReader<Key, StoredValue> for &TrackingCopy<R>

The purpose of this implementation is to allow a “snapshot” mechanism for TrackingCopy. The state of a TrackingCopy (including the effects of any transforms it has accumulated) can be read using an immutable reference to that TrackingCopy via this trait implementation. See TrackingCopy::fork for more information.

type Error = <R as StateReader<Key, StoredValue>>::Error

An error which occurs when reading state

fn read( &self, correlation_id: CorrelationId, key: &Key ) -> Result<Option<StoredValue>, Self::Error>

Returns the state value from the corresponding key

fn read_with_proof( &self, correlation_id: CorrelationId, key: &Key ) -> Result<Option<TrieMerkleProof<Key, StoredValue>>, Self::Error>

Returns the merkle proof of the state value from the corresponding key

fn keys_with_prefix( &self, correlation_id: CorrelationId, prefix: &[u8] ) -> Result<Vec<Key>, Self::Error>

Returns the keys in the trie matching prefix.

impl<R> TrackingCopyExt<R> for TrackingCopy<R>where R: StateReader<Key, StoredValue>, R::Error: Into<Error>,

fn get_contract_wasm( &mut self, correlation_id: CorrelationId, contract_wasm_hash: ContractWasmHash ) -> Result<ContractWasm, Self::Error>

Gets a contract wasm by Key

fn get_contract( &mut self, correlation_id: CorrelationId, contract_hash: ContractHash ) -> Result<Contract, Self::Error>

Gets a contract header by Key

type Error = Error

The type for the returned errors.

fn get_account( &mut self, correlation_id: CorrelationId, account_hash: AccountHash ) -> Result<Account, Self::Error>

Gets the account at a given account address.

fn read_account( &mut self, correlation_id: CorrelationId, account_hash: AccountHash ) -> Result<Account, Self::Error>

Reads the account at a given account address.

fn get_purse_balance_key( &self, _correlation_id: CorrelationId, purse_key: Key ) -> Result<Key, Self::Error>

Gets the purse balance key for a given purse id

fn get_purse_balance( &self, correlation_id: CorrelationId, key: Key ) -> Result<Motes, Self::Error>

Gets the balance at a given balance key.

fn get_purse_balance_key_with_proof( &self, correlation_id: CorrelationId, purse_key: Key ) -> Result<(Key, TrieMerkleProof<Key, StoredValue>), Self::Error>

Gets the purse balance key for a given purse id and provides a Merkle proof.

fn get_purse_balance_with_proof( &self, correlation_id: CorrelationId, key: Key ) -> Result<(Motes, TrieMerkleProof<Key, StoredValue>), Self::Error>

Gets the balance at a given balance key and provides a Merkle proof.

fn get_contract_package( &mut self, correlation_id: CorrelationId, contract_package_hash: ContractPackageHash ) -> Result<ContractPackage, Self::Error>

Gets a contract package by Key.

fn get_system_contracts( &mut self, correlation_id: CorrelationId ) -> Result<SystemContractRegistry, Self::Error>

Gets the system contract registry.

fn get_checksum_registry( &mut self, correlation_id: CorrelationId ) -> Result<Option<ChecksumRegistry>, Self::Error>

Gets the system checksum registry.