Trait KeyValueRead 

pub trait KeyValueRead {
    // Required methods
    fn control(&self) -> &StorageReadControl;
    fn revision(
        &self,
        prefixes: &[&[u8]],
    ) -> StorageBackendResult<KeyValueReadRevision>;
    fn visit_value(
        &self,
        key: &[u8],
        visit: &mut ValueReadVisitor<'_>,
    ) -> StorageBackendResult<()>;
    fn visit_prefix(
        &self,
        prefix: &[u8],
        visit: &mut KeyValueReadVisitor<'_>,
    ) -> StorageBackendResult<()>;

    // Provided methods
    fn marker_fingerprint(
        &self,
        _key: &[u8],
    ) -> StorageBackendResult<Option<[u8; 32]>> { ... }
    fn record_revision(
        &self,
        _key: &[u8],
    ) -> StorageBackendResult<Option<KeyValueReadRevision>> { ... }
    fn retained_source(
        &self,
        _key: &[u8],
    ) -> StorageBackendResult<Option<Arc<dyn KeyValueRead + Send + Sync>>> { ... }
    fn retain(
        &self,
        prefixes: &[&[u8]],
    ) -> StorageBackendResult<Arc<dyn KeyValueRead + Send + Sync>> { ... }
    fn visit_values(
        &self,
        keys: &mut KeyValueReadKeyIterator<'_>,
        visit: &mut KeyValuePointVisitor<'_>,
    ) -> StorageBackendResult<()> { ... }
    fn visit_key_presence(
        &self,
        keys: &mut KeyValueReadKeyIterator<'_>,
        visit: &mut KeyPresenceVisitor<'_>,
    ) -> StorageBackendResult<()> { ... }
    fn visit_value_budgeted(
        &self,
        _key: &[u8],
        control: &StorageReadControl,
        _visit: &mut ValueReadVisitor<'_>,
    ) -> StorageBackendResult<()> { ... }
    fn visit_value_bounded(
        &self,
        _key: &[u8],
        _max_bytes: usize,
        control: &StorageReadControl,
        _visit: &mut ValueReadVisitor<'_>,
    ) -> StorageBackendResult<()> { ... }
    fn visit_prefix_after(
        &self,
        _prefix: &[u8],
        _after: Option<&[u8]>,
        _limit: usize,
        control: &StorageReadControl,
        _visit: &mut KeyValueReadVisitor<'_>,
    ) -> StorageBackendResult<()> { ... }
    fn visit_keys_after(
        &self,
        _prefix: &[u8],
        _after: Option<&[u8]>,
        _limit: usize,
        control: &StorageReadControl,
        _visit: &mut KeyReadVisitor<'_>,
    ) -> StorageBackendResult<()> { ... }
    fn contains_prefix_budgeted(
        &self,
        _prefix: &[u8],
        control: &StorageReadControl,
    ) -> StorageBackendResult<bool> { ... }
    fn get(&self, key: &[u8]) -> StorageBackendResult<Option<BudgetedVec<u8>>> { ... }
}

A fixed read boundary supplied by the store. Borrowed visitors must not reenter persistence; compound reads make successive calls through this same reader.

Required Methods

fn control(&self) -> &StorageReadControl

fn revision( &self, prefixes: &[&[u8]], ) -> StorageBackendResult<KeyValueReadRevision>

fn visit_value( &self, key: &[u8], visit: &mut ValueReadVisitor<'_>, ) -> StorageBackendResult<()>

fn visit_prefix( &self, prefix: &[u8], visit: &mut KeyValueReadVisitor<'_>, ) -> StorageBackendResult<()>

Provided Methods

fn marker_fingerprint( &self, _key: &[u8], ) -> StorageBackendResult<Option<[u8; 32]>>

Versioned identity of both committed and private inputs to one shared change marker. Unlike a final record revision, a private marker cannot hide a changed committed input. Unsupported providers return None.

fn record_revision( &self, _key: &[u8], ) -> StorageBackendResult<Option<KeyValueReadRevision>>

Identity of one live record on this fixed view. Unlike a view revision, unrelated commits do not change it. Compare identities only for the same logical key; missing records and tombstones return None. Providers without exact committed/private record provenance must reject this capability.

fn retained_source( &self, _key: &[u8], ) -> StorageBackendResult<Option<Arc<dyn KeyValueRead + Send + Sync>>>

Read source attached to this exact private metadata replacement. Absence never authorizes opening a newer snapshot. Committed values have no attachment; provider wrappers translate the metadata key but preserve the source’s own key space and controls.

fn retain( &self, prefixes: &[&[u8]], ) -> StorageBackendResult<Arc<dyn KeyValueRead + Send + Sync>>

Retain this committed/private boundary after the callback returns. Callers may only read the selected prefixes. The default copies selected bytes under this reader’s allowance; versioned providers retain their existing visibility owners without loading values.

fn visit_values( &self, keys: &mut KeyValueReadKeyIterator<'_>, visit: &mut KeyValuePointVisitor<'_>, ) -> StorageBackendResult<()>

Borrow requested values in input order on this boundary. Key production and callbacks are internal and must not reenter persistence. A false visitor or an error stops before producing the next key; defaults require only ordinary point reads.

fn visit_key_presence( &self, keys: &mut KeyValueReadKeyIterator<'_>, visit: &mut KeyPresenceVisitor<'_>, ) -> StorageBackendResult<()>

Probe requested identities in input order without loading their values. The default uses the existing key-only scan capability; versioned readers reuse private selection cursors.

fn visit_value_budgeted( &self, _key: &[u8], control: &StorageReadControl, _visit: &mut ValueReadVisitor<'_>, ) -> StorageBackendResult<()>

Visit one value on this same boundary, charging temporary provider buffers to the supplied query allowance.

fn visit_value_bounded( &self, _key: &[u8], _max_bytes: usize, control: &StorageReadControl, _visit: &mut ValueReadVisitor<'_>, ) -> StorageBackendResult<()>

Check a value’s encoded size before provider materialization on this same committed/private view.

fn visit_prefix_after( &self, _prefix: &[u8], _after: Option<&[u8]>, _limit: usize, control: &StorageReadControl, _visit: &mut KeyValueReadVisitor<'_>, ) -> StorageBackendResult<()>

Visit at most limit values in key order, strictly after after, without advancing this read boundary.

fn visit_keys_after( &self, _prefix: &[u8], _after: Option<&[u8]>, _limit: usize, control: &StorageReadControl, _visit: &mut KeyReadVisitor<'_>, ) -> StorageBackendResult<()>

Visit at most limit live keys in ascending order, strictly after after, without reading their values or advancing this boundary. Capable wrappers must preserve this key-only contract.

fn contains_prefix_budgeted( &self, _prefix: &[u8], control: &StorageReadControl, ) -> StorageBackendResult<bool>

Probe live keys on this boundary without materializing their values.

fn get(&self, key: &[u8]) -> StorageBackendResult<Option<BudgetedVec<u8>>>

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl KeyValueRead for Budgeted<OwnedRead>

fn control(&self) -> &StorageReadControl

fn revision( &self, prefixes: &[&[u8]], ) -> StorageBackendResult<KeyValueReadRevision>

fn record_revision( &self, key: &[u8], ) -> StorageBackendResult<Option<KeyValueReadRevision>>

fn retained_source( &self, key: &[u8], ) -> StorageBackendResult<Option<Arc<dyn KeyValueRead + Send + Sync>>>

fn retain( &self, prefixes: &[&[u8]], ) -> StorageBackendResult<Arc<dyn KeyValueRead + Send + Sync>>

fn visit_value( &self, key: &[u8], visit: &mut ValueReadVisitor<'_>, ) -> StorageBackendResult<()>

fn visit_prefix( &self, prefix: &[u8], visit: &mut KeyValueReadVisitor<'_>, ) -> StorageBackendResult<()>

fn visit_value_budgeted( &self, key: &[u8], control: &StorageReadControl, visit: &mut ValueReadVisitor<'_>, ) -> StorageBackendResult<()>

fn visit_value_bounded( &self, key: &[u8], max_bytes: usize, control: &StorageReadControl, visit: &mut ValueReadVisitor<'_>, ) -> StorageBackendResult<()>

fn visit_prefix_after( &self, prefix: &[u8], after: Option<&[u8]>, limit: usize, control: &StorageReadControl, visit: &mut KeyValueReadVisitor<'_>, ) -> StorageBackendResult<()>

fn visit_keys_after( &self, prefix: &[u8], after: Option<&[u8]>, limit: usize, control: &StorageReadControl, visit: &mut KeyReadVisitor<'_>, ) -> StorageBackendResult<()>

fn contains_prefix_budgeted( &self, prefix: &[u8], control: &StorageReadControl, ) -> StorageBackendResult<bool>

Implementors

impl KeyValueRead for RecordRead<'_>