Struct PrefixMatch 

pub struct PrefixMatch {
    pub matched_blocks: Vec<u32>,
    pub matched_disk_block_ids: Vec<u32>,
    pub matched_tokens: usize,
    pub ssm_snapshot: Option<usize>,
    pub ssm_snapshot_tokens: usize,
    pub ssm_snapshot_tier_key: Option<u64>,
    pub ssm_snapshot_tier_tokens: usize,
    pub ssm_snapshot_is_tail: bool,
}

2026-09-26: Result of looking up a token sequence in the prefix cache.

Fields

matched_blocks: Vec<u32>

2026-09-26: KV blocks to reuse, in token order.

matched_disk_block_ids: Vec<u32>

2026-09-26: --high-speed-swap disk-block ids parallel to matched_blocks, u32::MAX where a block has none; empty when no matched block has one.

matched_tokens: usize

2026-09-26: Tokens matched. Block-aligned unless partial-tail sharing (METRALE_PREFIX_SUBBLOCK) matched into a block.

ssm_snapshot: Option<usize>

2026-09-26: The resident SSM snapshot slot of the deepest snapshot within the match, if that snapshot is resident.

ssm_snapshot_tokens: usize

2026-09-26: Tokens covered by ssm_snapshot, at most matched_tokens; SSM state for the tokens between is not covered.

ssm_snapshot_tier_key: Option<u64>

2026-09-26: The tier key (prefix hash) when the deepest snapshot within the match is spilled; ssm_snapshot is then None. The caller faults it in and calls PrefixCache::promote_snapshot.

ssm_snapshot_tier_tokens: usize

2026-09-26: Tokens covered by ssm_snapshot_tier_key.

ssm_snapshot_is_tail: bool

2026-09-26: Whether the matched snapshot is a session tail (PrefixCache::insert_tail_snapshot).

Implementations

impl PrefixMatch

pub fn empty() -> Self

2026-09-26: Empty match (no cached prefix found).

pub fn is_empty(&self) -> bool

2026-09-26: Whether any prefix was matched.

Trait Implementations

impl Clone for PrefixMatch

fn clone(&self) -> PrefixMatch

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for PrefixMatch

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.