Trait StatementStore 

pub trait StatementStore: Send + Sync {
    // Required methods
    fn statements(&self) -> Result<Vec<(Hash, Statement)>>;
    fn take_recent_statements(&self) -> Result<Vec<(u64, Hash, Statement)>>;
    fn statement(&self, hash: &Hash) -> Result<Option<Statement>>;
    fn has_statement(&self, hash: &Hash) -> bool;
    fn statements_by_hashes(
        &self,
        hashes: &[Hash],
        filter: &mut dyn FnMut(&Hash, &[u8], &Statement) -> FilterDecision,
    ) -> Result<(Vec<(Hash, Statement)>, usize)>;
    fn admission_watermark(&self) -> Result<u64>;
    fn admitted_statements(
        &self,
        cursor: u64,
        watermark: u64,
        scan_limit: usize,
        filter: &mut dyn FnMut(&Hash, &[u8], &Statement) -> FilterDecision,
    ) -> Result<AdmittedBatch>;
    fn broadcasts(&self, match_all_topics: &[Topic]) -> Result<Vec<Vec<u8>>>;
    fn posted(
        &self,
        match_all_topics: &[Topic],
        dest: [u8; 32],
    ) -> Result<Vec<Vec<u8>>>;
    fn posted_clear(
        &self,
        match_all_topics: &[Topic],
        dest: [u8; 32],
    ) -> Result<Vec<Vec<u8>>>;
    fn broadcasts_stmt(
        &self,
        match_all_topics: &[Topic],
    ) -> Result<Vec<Vec<u8>>>;
    fn posted_stmt(
        &self,
        match_all_topics: &[Topic],
        dest: [u8; 32],
    ) -> Result<Vec<Vec<u8>>>;
    fn posted_clear_stmt(
        &self,
        match_all_topics: &[Topic],
        dest: [u8; 32],
    ) -> Result<Vec<Vec<u8>>>;
    fn submit(
        &self,
        statement: Statement,
        source: StatementSource,
    ) -> SubmitResult;
    fn remove(&self, hash: &Hash) -> Result<()>;
    fn remove_by(&self, who: [u8; 32]) -> Result<()>;

    // Provided method
    fn subscription_topics(&self) -> HashSet<Topic> { ... }
}

Statement store API.

Required Methods

fn statements(&self) -> Result<Vec<(Hash, Statement)>>

Return all statements.

fn take_recent_statements(&self) -> Result<Vec<(u64, Hash, Statement)>>

Return recent statements with their admission sequence numbers, oldest admission first, and clear the internal index.

This consumes and clears the recently received statements, allowing new statements to be collected from this point forward.

fn statement(&self, hash: &Hash) -> Result<Option<Statement>>

Get statement by hash.

fn has_statement(&self, hash: &Hash) -> bool

Check if statement exists in the store

Fast index check without accessing the DB.

fn statements_by_hashes( &self, hashes: &[Hash], filter: &mut dyn FnMut(&Hash, &[u8], &Statement) -> FilterDecision, ) -> Result<(Vec<(Hash, Statement)>, usize)>

Fetch statements by their hashes with a filter callback.

The callback receives (hash, encoded_bytes, decoded_statement) and returns:

• Skip: ignore this statement, continue to next
• Take: include this statement in the result, continue to next
• Abort: stop iteration, return collected statements so far

Returns (statements, number_of_hashes_processed).

fn admission_watermark(&self) -> Result<u64>

One past the newest assigned admission sequence number.

Every statement currently in the store was admitted below this boundary, so it serves as the watermark for a subsequent Self::admitted_statements walk.

fn admitted_statements( &self, cursor: u64, watermark: u64, scan_limit: usize, filter: &mut dyn FnMut(&Hash, &[u8], &Statement) -> FilterDecision, ) -> Result<AdmittedBatch>

Walk the admission journal from cursor (inclusive) towards watermark (exclusive), collecting statements through a filter callback.

The callback receives (hash, encoded_bytes, decoded_statement) and returns:

• Skip: leave this statement out of the batch, continue to next
• Take: include this statement in the batch, continue to next
• Abort: stop the walk before this statement

Sequence numbers whose statement has left the store are passed over. The returned cursor sits after every visited statement except an Aborted one, which the next walk revisits first.

A call visits at most scan_limit journal entries, passed-over ones included, so its cost stays bounded even when the filter takes nothing. scan_limit must be positive: a walk that visits no entries cannot advance the cursor. A walk stopped by the limit returns a partial cursor to resume from, exactly like an Abort.

fn broadcasts(&self, match_all_topics: &[Topic]) -> Result<Vec<Vec<u8>>>

Return the data of all known statements which include all topics and have no DecryptionKey field.

fn posted( &self, match_all_topics: &[Topic], dest: [u8; 32], ) -> Result<Vec<Vec<u8>>>

Return the data of all known statements whose decryption key is identified as dest (this will generally be the public key or a hash thereof for symmetric ciphers, or a hash of the private key for symmetric ciphers).

fn posted_clear( &self, match_all_topics: &[Topic], dest: [u8; 32], ) -> Result<Vec<Vec<u8>>>

Return the decrypted data of all known statements whose decryption key is identified as dest. The key must be available to the client.

fn broadcasts_stmt(&self, match_all_topics: &[Topic]) -> Result<Vec<Vec<u8>>>

Return all known statements which include all topics and have no DecryptionKey field.

fn posted_stmt( &self, match_all_topics: &[Topic], dest: [u8; 32], ) -> Result<Vec<Vec<u8>>>

Return all known statements whose decryption key is identified as dest (this will generally be the public key or a hash thereof for symmetric ciphers, or a hash of the private key for symmetric ciphers).

fn posted_clear_stmt( &self, match_all_topics: &[Topic], dest: [u8; 32], ) -> Result<Vec<Vec<u8>>>

Return the statement and the decrypted data of all known statements whose decryption key is identified as dest. The key must be available to the client.

The result is for each statement: the SCALE-encoded statement concatenated to the decrypted data.

fn submit(&self, statement: Statement, source: StatementSource) -> SubmitResult

Submit a statement.

fn remove(&self, hash: &Hash) -> Result<()>

Remove a statement from the store.

fn remove_by(&self, who: [u8; 32]) -> Result<()>

Remove all statements authored by who.

Provided Methods

fn subscription_topics(&self) -> HashSet<Topic>

Topics across all live statement subscriptions, for advertising topic affinity.

Defaults to empty for stores without a subscription manager.

Implementors