nodedb-vector 0.6.0

Shared vector engine (HNSW index + distance functions) for NodeDB Origin and Lite
Documentation 
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// SPDX-License-Identifier: Apache-2.0

//! Soft deletion and the counts derived from it.
//!
//! Deleting a node marks it rather than removing it, because removal would
//! renumber every id the graph's neighbor lists refer to. The tombstone ratio
//! is what compaction watches to decide when the graph is worth rebuilding.

use super::state::HnswIndex;

impl HnswIndex {
    pub fn len(&self) -> usize {
        self.nodes.len()
    }

    pub fn live_count(&self) -> usize {
        self.nodes.len() - self.tombstone_count()
    }

    pub fn tombstone_count(&self) -> usize {
        self.nodes.iter().filter(|n| n.deleted).count()
    }

    /// Tombstone ratio: fraction of nodes that are deleted.
    pub fn tombstone_ratio(&self) -> f64 {
        if self.nodes.is_empty() {
            0.0
        } else {
            self.tombstone_count() as f64 / self.nodes.len() as f64
        }
    }

    pub fn is_empty(&self) -> bool {
        self.live_count() == 0
    }

    /// Soft-delete a vector by internal node ID.
    pub fn delete(&mut self, id: u32) -> bool {
        if let Some(node) = self.nodes.get_mut(id as usize) {
            if node.deleted {
                return false;
            }
            node.deleted = true;
            true
        } else {
            false
        }
    }

    pub fn is_deleted(&self, id: u32) -> bool {
        self.nodes.get(id as usize).is_none_or(|n| n.deleted)
    }

    pub fn undelete(&mut self, id: u32) -> bool {
        if let Some(node) = self.nodes.get_mut(id as usize)
            && node.deleted
        {
            node.deleted = false;
            return true;
        }
        false
    }
}