mushroomdb 0.1.2

Embedded graph database with Cypher queries, rule triggers, and Arrow export
Documentation 
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use core_storage::fs::Fs;
use std::collections::HashSet;

use crate::db::GraphDb;

/// Query-scoped node visibility filter (ACL primitive).
///
/// When a `NodeMask` is passed to `query_masked`, only nodes whose dense id
/// appears in `visible` will be returned by label scans, key lookups, and
/// neighbor expansions. Edges where either endpoint is hidden are silently
/// dropped from the result.
///
/// Unknown keys in `from_keys` are silently ignored (they resolve to no id).
/// An empty mask hides every node.
pub struct NodeMask {
    pub(crate) visible: HashSet<u32>,
}

impl NodeMask {
    /// Resolve string keys to dense ids and build a mask.
    ///
    /// Keys that do not exist in the database are ignored.
    pub fn from_keys<'a, F: Fs>(db: &GraphDb<F>, keys: impl IntoIterator<Item = &'a str>) -> Self {
        let visible = keys.into_iter().filter_map(|k| db.ids().get(k)).collect();
        NodeMask { visible }
    }

    pub fn len(&self) -> usize {
        self.visible.len()
    }

    pub fn is_empty(&self) -> bool {
        self.visible.is_empty()
    }
}