[][src]Trait sc_client_api::backend::StateBackend

pub trait StateBackend<H>: Debug where
    H: Hasher, 
{ type Error: Error; type Transaction: Consolidate + Default + Send; type TrieBackendStorage: TrieBackendStorage<H>; fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error>;
fn child_storage(
        &self,
        child_info: &ChildInfo,
        key: &[u8]
    ) -> Result<Option<Vec<u8>>, Self::Error>;
fn next_storage_key(
        &self,
        key: &[u8]
    ) -> Result<Option<Vec<u8>>, Self::Error>;
fn next_child_storage_key(
        &self,
        child_info: &ChildInfo,
        key: &[u8]
    ) -> Result<Option<Vec<u8>>, Self::Error>;
fn for_keys_in_child_storage<F>(&self, child_info: &ChildInfo, f: F)
    where
        F: FnMut(&[u8])
;
fn for_key_values_with_prefix<F>(&self, prefix: &[u8], f: F)
    where
        F: FnMut(&[u8], &[u8])
;
fn for_child_keys_with_prefix<F>(
        &self,
        child_info: &ChildInfo,
        prefix: &[u8],
        f: F
    )
    where
        F: FnMut(&[u8])
;
fn storage_root<'a>(
        &self,
        delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>
    ) -> (<H as Hasher>::Out, Self::Transaction)
    where
        <H as Hasher>::Out: Ord
;
fn child_storage_root<'a>(
        &self,
        child_info: &ChildInfo,
        delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>
    ) -> (<H as Hasher>::Out, bool, Self::Transaction)
    where
        <H as Hasher>::Out: Ord
;
fn pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)>;
fn register_overlay_stats(&mut self, _stats: &StateMachineStats);
fn usage_info(&self) -> UsageInfo; fn storage_hash(
        &self,
        key: &[u8]
    ) -> Result<Option<<H as Hasher>::Out>, Self::Error> { ... }
fn child_storage_hash(
        &self,
        child_info: &ChildInfo,
        key: &[u8]
    ) -> Result<Option<<H as Hasher>::Out>, Self::Error> { ... }
fn exists_storage(&self, key: &[u8]) -> Result<bool, Self::Error> { ... }
fn exists_child_storage(
        &self,
        child_info: &ChildInfo,
        key: &[u8]
    ) -> Result<bool, Self::Error> { ... }
fn for_keys_with_prefix<F>(&self, prefix: &[u8], f: F)
    where
        F: FnMut(&[u8])
, { ... }
fn keys(&self, prefix: &[u8]) -> Vec<Vec<u8>> { ... }
fn child_keys(&self, child_info: &ChildInfo, prefix: &[u8]) -> Vec<Vec<u8>> { ... }
fn as_trie_backend(
        &mut self
    ) -> Option<&TrieBackend<Self::TrieBackendStorage, H>> { ... }
fn full_storage_root<'a>(
        &self,
        delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>,
        child_deltas: impl Iterator<Item = (&'a ChildInfo, impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>)>
    ) -> (<H as Hasher>::Out, Self::Transaction)
    where
        <H as Hasher>::Out: Ord,
        <H as Hasher>::Out: Encode
, { ... }
fn wipe(&self) -> Result<(), Self::Error> { ... }
fn commit(
        &self,
        <H as Hasher>::Out,
        Self::Transaction,
        Vec<(Vec<u8>, Option<Vec<u8>>)>,
        Vec<(Vec<u8>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>
    ) -> Result<(), Self::Error> { ... }
fn read_write_count(&self) -> (u32, u32, u32, u32) { ... }
fn reset_read_write_count(&self) { ... }
fn get_whitelist(&self) -> Vec<TrackedStorageKey> { ... }
fn set_whitelist(&self, Vec<TrackedStorageKey>) { ... } }

A state backend is used to read state data and can have changes committed to it.

The clone operation (if implemented) should be cheap.

Associated Types

type Error: Error

An error type when fetching data is not possible.

type Transaction: Consolidate + Default + Send

Storage changes to be applied if committing

type TrieBackendStorage: TrieBackendStorage<H>

Type of trie backend storage.

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Required methods

fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error>

Get keyed storage or None if there is nothing associated.

fn child_storage(
    &self,
    child_info: &ChildInfo,
    key: &[u8]
) -> Result<Option<Vec<u8>>, Self::Error>

Get keyed child storage or None if there is nothing associated.

fn next_storage_key(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error>

Return the next key in storage in lexicographic order or None if there is no value.

fn next_child_storage_key(
    &self,
    child_info: &ChildInfo,
    key: &[u8]
) -> Result<Option<Vec<u8>>, Self::Error>

Return the next key in child storage in lexicographic order or None if there is no value.

fn for_keys_in_child_storage<F>(&self, child_info: &ChildInfo, f: F) where
    F: FnMut(&[u8]), 

Retrieve all entries keys of child storage and call f for each of those keys.

fn for_key_values_with_prefix<F>(&self, prefix: &[u8], f: F) where
    F: FnMut(&[u8], &[u8]), 

Retrieve all entries keys and values of which start with the given prefix and call f for each of those keys.

fn for_child_keys_with_prefix<F>(
    &self,
    child_info: &ChildInfo,
    prefix: &[u8],
    f: F
) where
    F: FnMut(&[u8]), 

Retrieve all child entries keys which start with the given prefix and call f for each of those keys.

fn storage_root<'a>(
    &self,
    delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>
) -> (<H as Hasher>::Out, Self::Transaction) where
    <H as Hasher>::Out: Ord

Calculate the storage root, with given delta over what is already stored in the backend, and produce a "transaction" that can be used to commit. Does not include child storage updates.

fn child_storage_root<'a>(
    &self,
    child_info: &ChildInfo,
    delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>
) -> (<H as Hasher>::Out, bool, Self::Transaction) where
    <H as Hasher>::Out: Ord

Calculate the child storage root, with given delta over what is already stored in the backend, and produce a "transaction" that can be used to commit. The second argument is true if child storage root equals default storage root.

fn pairs(&self) -> Vec<(Vec<u8>, Vec<u8>)>

Get all key/value pairs into a Vec.

fn register_overlay_stats(&mut self, _stats: &StateMachineStats)

Register stats from overlay of state machine.

By default nothing is registered.

fn usage_info(&self) -> UsageInfo

Query backend usage statistics (i/o, memory)

Not all implementations are expected to be able to do this. In the case when they don't, empty statistics is returned.

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Provided methods

fn storage_hash(
    &self,
    key: &[u8]
) -> Result<Option<<H as Hasher>::Out>, Self::Error>

Get keyed storage value hash or None if there is nothing associated.

fn child_storage_hash(
    &self,
    child_info: &ChildInfo,
    key: &[u8]
) -> Result<Option<<H as Hasher>::Out>, Self::Error>

Get child keyed storage value hash or None if there is nothing associated.

fn exists_storage(&self, key: &[u8]) -> Result<bool, Self::Error>

true if a key exists in storage.

fn exists_child_storage(
    &self,
    child_info: &ChildInfo,
    key: &[u8]
) -> Result<bool, Self::Error>

true if a key exists in child storage.

fn for_keys_with_prefix<F>(&self, prefix: &[u8], f: F) where
    F: FnMut(&[u8]), 

Retrieve all entries keys which start with the given prefix and call f for each of those keys.

fn keys(&self, prefix: &[u8]) -> Vec<Vec<u8>>

Get all keys with given prefix

fn child_keys(&self, child_info: &ChildInfo, prefix: &[u8]) -> Vec<Vec<u8>>

Get all keys of child storage with given prefix

fn as_trie_backend(
    &mut self
) -> Option<&TrieBackend<Self::TrieBackendStorage, H>>

Try convert into trie backend.

fn full_storage_root<'a>(
    &self,
    delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>,
    child_deltas: impl Iterator<Item = (&'a ChildInfo, impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>)>
) -> (<H as Hasher>::Out, Self::Transaction) where
    <H as Hasher>::Out: Ord,
    <H as Hasher>::Out: Encode, 

Calculate the storage root, with given delta over what is already stored in the backend, and produce a "transaction" that can be used to commit. Does include child storage updates.

fn wipe(&self) -> Result<(), Self::Error>

Wipe the state database.

fn commit(
    &self,
    <H as Hasher>::Out,
    Self::Transaction,
    Vec<(Vec<u8>, Option<Vec<u8>>)>,
    Vec<(Vec<u8>, Vec<(Vec<u8>, Option<Vec<u8>>)>)>
) -> Result<(), Self::Error>

Commit given transaction to storage.

fn read_write_count(&self) -> (u32, u32, u32, u32)

Get the read/write count of the db

fn reset_read_write_count(&self)

Get the read/write count of the db

fn get_whitelist(&self) -> Vec<TrackedStorageKey>

Get the whitelist for tracking db reads/writes

fn set_whitelist(&self, Vec<TrackedStorageKey>)

Update the whitelist for tracking db reads/writes

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Implementations on Foreign Types

impl<'a, S, H> Backend<H> for ProvingBackend<'a, S, H> where
    H: 'a + Hasher,
    S: 'a + TrieBackendStorage<H>,
    <H as Hasher>::Out: Ord,
    <H as Hasher>::Out: Codec, 
[src]

type Error = String

type Transaction = <S as TrieBackendStorage<H>>::Overlay

type TrieBackendStorage = S

impl<'a, T, H> Backend<H> for &'a T where
    H: Hasher,
    T: Backend<H>, 
[src]

type Error = <T as Backend<H>>::Error

type Transaction = <T as Backend<H>>::Transaction

type TrieBackendStorage = <T as Backend<H>>::TrieBackendStorage

impl<S, H> Backend<H> for TrieBackend<S, H> where
    H: Hasher,
    S: TrieBackendStorage<H>,
    <H as Hasher>::Out: Ord,
    <H as Hasher>::Out: Codec, 
[src]

type Error = String

type Transaction = <S as TrieBackendStorage<H>>::Overlay

type TrieBackendStorage = S

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Implementors

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