Struct StorageMetadataIndex 

pub struct StorageMetadataIndex {
    pub entries: HashMap<u64, MetadataIndexEntry>,
    pub field_index: HashMap<MetadataField, Vec<u64>>,
    pub stats: MetadataIndexStats,
}

Secondary index over block metadata fields enabling efficient filtered queries.

Design

Two data structures are maintained in tandem:

• entries — a HashMap<block_id, MetadataIndexEntry> for O(1) point lookups and to support fast replacement when the same block is re-inserted.
• field_index — an inverted index mapping each MetadataField to the set of block_ids that carry that field.

Queries intersect the posting lists of all must_have fields (giving the candidate set), then subtract any block whose entry contains a must_not_have field.

Fields

entries: HashMap<u64, MetadataIndexEntry>

Primary store: block_id → entry.

field_index: HashMap<MetadataField, Vec<u64>>

Inverted index: field → block_ids.

stats: MetadataIndexStats

Running statistics.

Implementations

impl StorageMetadataIndex

pub fn new() -> Self

Create an empty StorageMetadataIndex.

pub fn insert(&mut self, entry: MetadataIndexEntry)

Insert (or replace) a block entry.

If a block with the same block_id already exists its old field index postings are removed before the new entry is written.

pub fn remove(&mut self, block_id: u64) -> bool

Remove the entry for block_id.

Returns true if an entry was present and removed, false otherwise.

pub fn query(&mut self, q: &MetadataQuery) -> Vec<MetadataQueryResult>

Execute a structured metadata query.

Algorithm

1. Candidate set – if must_have is empty, all block IDs are candidates; otherwise the candidate set is the intersection of the posting lists for each must_have field.
2. Exclusion – remove any candidate whose entry contains any must_not_have field.
3. Projection – build a MetadataQueryResult per surviving candidate recording which must_have fields matched.
4. Sort – apply sort_by if present.
5. Limit – truncate to limit if present.
6. Stats – increment total_queries.

pub fn get(&self, block_id: u64) -> Option<&MetadataIndexEntry>

Return a reference to the entry for block_id, or None.

pub fn stats(&self) -> &MetadataIndexStats

Return a reference to the current statistics snapshot.

Trait Implementations

impl Default for StorageMetadataIndex

fn default() -> Self

Returns the “default value” for a type.