Function build_value_partitions

nodedb-query/src/window/value_eval.rs:93–115

(
    rows: &[Vec<Value>],
    column_index: &HashMap<String, usize>,
    spec: &WindowFuncSpec,
)

// ── Partition building ────────────────────────────────────────────────────────

fn build_value_partitions(
    rows: &[Vec<Value>],
    column_index: &HashMap<String, usize>,
    spec: &WindowFuncSpec,
) -> Result<Vec<Vec<usize>>, WindowError> {
    if spec.partition_by.is_empty() {
        return Ok(vec![(0..rows.len()).collect()]);
    }

    let mut groups: HashMap<String, Vec<usize>> = HashMap::new();
    let mut order: Vec<String> = Vec::new();

    for (i, row) in rows.iter().enumerate() {
        let key = partition_key(row, column_index, &spec.partition_by);
        let entry = groups.entry(key.clone()).or_default();
        if entry.is_empty() {
            order.push(key);
        }
        entry.push(i);
    }

    Ok(order.iter().filter_map(|k| groups.remove(k)).collect())
}

fn partition_key(
    row: &[Value],