[−][src]Trait sc_client_api::backend::Backend

pub trait Backend<Block: BlockT>: AuxStore + Send + Sync {
    type BlockImportOperation: BlockImportOperation<Block, State = Self::State>;
    type Blockchain: BlockchainBackend<Block>;
    type State: StateBackend<HashFor<Block>> + Send;
    type OffchainStorage: OffchainStorage;
    pub fn begin_operation(&self) -> Result<Self::BlockImportOperation>;

    pub fn begin_state_operation(
        &self, 
        operation: &mut Self::BlockImportOperation, 
        block: BlockId<Block>
    ) -> Result<()>;

    pub fn commit_operation(
        &self, 
        transaction: Self::BlockImportOperation
    ) -> Result<()>;

    pub fn finalize_block(
        &self, 
        block: BlockId<Block>, 
        justification: Option<Justification>
    ) -> Result<()>;

    pub fn blockchain(&self) -> &Self::Blockchain;

    pub fn usage_info(&self) -> Option<UsageInfo>;

    pub fn changes_trie_storage(
        &self
    ) -> Option<&dyn PrunableStateChangesTrieStorage<Block>>;

    pub fn offchain_storage(&self) -> Option<Self::OffchainStorage>;

    pub fn state_at(&self, block: BlockId<Block>) -> Result<Self::State>;

    pub fn revert(
        &self, 
        n: NumberFor<Block>, 
        revert_finalized: bool
    ) -> Result<(NumberFor<Block>, HashSet<Block::Hash>)>;

    pub fn get_import_lock(&self) -> &RwLock<()>;

    pub fn have_state_at(
        &self, 
        hash: &Block::Hash, 
        _number: NumberFor<Block>
    ) -> bool { ... }

    pub fn insert_aux<'a, 'b: 'a, 'c: 'a, I: IntoIterator<Item = &'a (&'c [u8], &'c [u8])>, D: IntoIterator<Item = &'a &'b [u8]>>(
        &self, 
        insert: I, 
        delete: D
    ) -> Result<()> { ... }

    pub fn get_aux(&self, key: &[u8]) -> Result<Option<Vec<u8>>> { ... }
}

Client backend.

Manages the data layer.

Note on state pruning: while an object from state_at is alive, the state should not be pruned. The backend should internally reference-count its state objects.

The same applies for live BlockImportOperations: while an import operation building on a parent P is alive, the state for P should not be pruned.

Associated Types

type BlockImportOperation: BlockImportOperation<Block, State = Self::State>[src]

Associated block insertion operation type.

type Blockchain: BlockchainBackend<Block>[src]

Associated blockchain backend type.

type State: StateBackend<HashFor<Block>> + Send[src]

Associated state backend type.

type OffchainStorage: OffchainStorage[src]

Offchain workers local storage.

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Required methods

pub fn begin_operation(&self) -> Result<Self::BlockImportOperation>[src]

Begin a new block insertion transaction with given parent block id.

When constructing the genesis, this is called with all-zero hash.

pub fn begin_state_operation(
    &self,
    operation: &mut Self::BlockImportOperation,
    block: BlockId<Block>
) -> Result<()>[src]

Note an operation to contain state transition.

pub fn commit_operation(
    &self,
    transaction: Self::BlockImportOperation
) -> Result<()>[src]

Commit block insertion.

pub fn finalize_block(
    &self,
    block: BlockId<Block>,
    justification: Option<Justification>
) -> Result<()>[src]

Finalize block with given Id.

This should only be called if the parent of the given block has been finalized.

pub fn blockchain(&self) -> &Self::Blockchain[src]

Returns reference to blockchain backend.

pub fn usage_info(&self) -> Option<UsageInfo>[src]

Returns current usage statistics.

pub fn changes_trie_storage(
    &self
) -> Option<&dyn PrunableStateChangesTrieStorage<Block>>[src]

Returns reference to changes trie storage.

pub fn offchain_storage(&self) -> Option<Self::OffchainStorage>[src]

Returns a handle to offchain storage.

pub fn state_at(&self, block: BlockId<Block>) -> Result<Self::State>[src]

Returns state backend with post-state of given block.

pub fn revert(
    &self,
    n: NumberFor<Block>,
    revert_finalized: bool
) -> Result<(NumberFor<Block>, HashSet<Block::Hash>)>[src]

Attempts to revert the chain by n blocks. If revert_finalized is set it will attempt to revert past any finalized block, this is unsafe and can potentially leave the node in an inconsistent state.

Returns the number of blocks that were successfully reverted and the list of finalized blocks that has been reverted.

pub fn get_import_lock(&self) -> &RwLock<()>[src]

Gain access to the import lock around this backend.

Note Backend isn't expected to acquire the lock by itself ever. Rather the using components should acquire and hold the lock whenever they do something that the import of a block would interfere with, e.g. importing a new block or calculating the best head.

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Provided methods

pub fn have_state_at(
    &self,
    hash: &Block::Hash,
    _number: NumberFor<Block>
) -> bool[src]

Returns true if state for given block is available.

pub fn insert_aux<'a, 'b: 'a, 'c: 'a, I: IntoIterator<Item = &'a (&'c [u8], &'c [u8])>, D: IntoIterator<Item = &'a &'b [u8]>>(
    &self,
    insert: I,
    delete: D
) -> Result<()>[src]

Insert auxiliary data into key-value store.

pub fn get_aux(&self, key: &[u8]) -> Result<Option<Vec<u8>>>[src]

Query auxiliary data from key-value store.

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Implementors

impl<Block: BlockT> Backend<Block> for Backend<Block> where
    Block::Hash: Ord, [src]

type BlockImportOperation = BlockImportOperation<Block>

type Blockchain = Blockchain<Block>

type State = InMemoryBackend<HashFor<Block>>

type OffchainStorage = OffchainStorage

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