dynamo-kv-router 1.3.0

KV Router - Radix tree for LLM KV cache routing
Documentation 
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// SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

use std::collections::hash_map::Entry;
use std::hash::Hash;
use std::sync::Arc;

use rustc_hash::FxHashMap;

/// Update an `Arc` lookup map for keys that should point at `node`.
///
/// Duplicate store/repair paths often revisit keys that already resolve to the
/// same node. Skipping those replacements avoids unnecessary hash table writes
/// and `Arc` refcount churn while still repairing stale entries. Returns the
/// number of entries that were inserted or changed.
pub(crate) fn update_arc_lookup_for_keys<K, T>(
    lookup: &mut FxHashMap<K, Arc<T>>,
    keys: impl IntoIterator<Item = K>,
    node: &Arc<T>,
) -> usize
where
    K: Eq + Hash,
{
    let mut changed = 0;

    for key in keys {
        match lookup.entry(key) {
            Entry::Occupied(mut entry) if !Arc::ptr_eq(entry.get(), node) => {
                entry.insert(Arc::clone(node));
                changed += 1;
            }
            Entry::Occupied(_) => {}
            Entry::Vacant(entry) => {
                entry.insert(Arc::clone(node));
                changed += 1;
            }
        }
    }

    changed
}