pub trait StateBackend<H>: Debugwhere
    H: Hasher,{
    type Error: Error;
    type TrieBackendStorage: TrieBackendStorage<H>;
    type RawIter: StorageIterator<H, Backend = Self, Error = Self::Error>;

Show 26 methods // Required methods fn storage(&self, key: &[u8]) -> Result<Option<Vec<u8>>, Self::Error>; fn storage_hash( &self, key: &[u8] ) -> Result<Option<<H as Hasher>::Out>, Self::Error>; fn closest_merkle_value( &self, key: &[u8] ) -> Result<Option<MerkleValue<<H as Hasher>::Out>>, Self::Error>; fn child_closest_merkle_value( &self, child_info: &ChildInfo, key: &[u8] ) -> Result<Option<MerkleValue<<H as Hasher>::Out>>, Self::Error>; fn child_storage( &self, child_info: &ChildInfo, key: &[u8] ) -> Result<Option<Vec<u8>>, Self::Error>; fn child_storage_hash( &self, child_info: &ChildInfo, key: &[u8] ) -> Result<Option<<H as Hasher>::Out>, 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 storage_root<'a>( &self, delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>, state_version: StateVersion ) -> (<H as Hasher>::Out, MemoryDB<H, PrefixedKey<H>, Vec<u8>>) where <H as Hasher>::Out: Ord; fn child_storage_root<'a>( &self, child_info: &ChildInfo, delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>, state_version: StateVersion ) -> (<H as Hasher>::Out, bool, MemoryDB<H, PrefixedKey<H>, Vec<u8>>) where <H as Hasher>::Out: Ord; fn raw_iter(&self, args: IterArgs<'_>) -> Result<Self::RawIter, Self::Error>; fn register_overlay_stats(&self, _stats: &StateMachineStats); fn usage_info(&self) -> UsageInfo; // Provided methods 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 pairs<'a>( &'a self, args: IterArgs<'_> ) -> Result<PairsIter<'a, H, Self::RawIter>, Self::Error> { ... } fn keys<'a>( &'a self, args: IterArgs<'_> ) -> Result<KeysIter<'a, H, Self::RawIter>, Self::Error> { ... } 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]>)>)>, state_version: StateVersion ) -> (<H as Hasher>::Out, MemoryDB<H, PrefixedKey<H>, Vec<u8>>) where <H as Hasher>::Out: Ord + Encode { ... } fn wipe(&self) -> Result<(), Self::Error> { ... } fn commit( &self, _: <H as Hasher>::Out, _: MemoryDB<H, PrefixedKey<H>, Vec<u8>>, _: 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>) { ... } fn proof_size(&self) -> Option<u32> { ... } fn get_read_and_written_keys(&self) -> Vec<(Vec<u8>, u32, u32, bool)> { ... }
}
Expand description

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

The clone operation (if implemented) should be cheap.

Required Associated Types§

type Error: Error

An error type when fetching data is not possible.

type TrieBackendStorage: TrieBackendStorage<H>

Type of trie backend storage.

type RawIter: StorageIterator<H, Backend = Self, Error = Self::Error>

Type of the raw storage iterator.

Required Methods§

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

Get keyed storage or None if there is nothing associated.

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

Get the merkle value or None if there is nothing associated.

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

Get the child merkle value or None if there is nothing associated.

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

Get child keyed child storage 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 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 storage_root<'a>( &self, delta: impl Iterator<Item = (&'a [u8], Option<&'a [u8]>)>, state_version: StateVersion ) -> (<H as Hasher>::Out, MemoryDB<H, PrefixedKey<H>, Vec<u8>>)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]>)>, state_version: StateVersion ) -> (<H as Hasher>::Out, bool, MemoryDB<H, PrefixedKey<H>, Vec<u8>>)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 raw_iter(&self, args: IterArgs<'_>) -> Result<Self::RawIter, Self::Error>

Returns a lifetimeless raw storage iterator.

fn register_overlay_stats(&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.

Provided Methods§

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 pairs<'a>( &'a self, args: IterArgs<'_> ) -> Result<PairsIter<'a, H, Self::RawIter>, Self::Error>

Get an iterator over key/value pairs.

fn keys<'a>( &'a self, args: IterArgs<'_> ) -> Result<KeysIter<'a, H, Self::RawIter>, Self::Error>

Get an iterator over keys.

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]>)>)>, state_version: StateVersion ) -> (<H as Hasher>::Out, MemoryDB<H, PrefixedKey<H>, Vec<u8>>)where <H as Hasher>::Out: Ord + 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, _: MemoryDB<H, PrefixedKey<H>, Vec<u8>>, _: 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

fn proof_size(&self) -> Option<u32>

Estimate proof size

fn get_read_and_written_keys(&self) -> Vec<(Vec<u8>, u32, u32, bool)>

Extend storage info for benchmarking db

Object Safety§

This trait is not object safe.

Implementors§

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impl<S, H, C, R> Backend<H> for TrieBackend<S, H, C, R>where S: TrieBackendStorage<H>, H: Hasher, C: TrieCacheProvider<H> + Send + Sync, R: TrieRecorderProvider<H> + Send + Sync, <H as Hasher>::Out: Ord + Codec,

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type Error = String

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type TrieBackendStorage = S

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type RawIter = RawIter<S, H, C, R>