Function extract_bytes

nodedb-query/src/msgpack_scan/aggregate_helpers.rs:65–72

Extract a field or expression result as raw msgpack bytes. Used by `count_distinct`, `approx_count_distinct`, `approx_topk`, etc.

(doc: &[u8], field: &str, expr: Option<&SqlExpr>)

/// Extract a field or expression result as raw msgpack bytes.
/// Used by `count_distinct`, `approx_count_distinct`, `approx_topk`, etc.
pub fn extract_bytes(doc: &[u8], field: &str, expr: Option<&SqlExpr>) -> Option<Vec<u8>> {
    if let Some(expr) = expr {
        let val = eval_expr(doc, expr)?;
        return nodedb_types::json_msgpack::value_to_msgpack(&val).ok();
    }
    let (start, end) = extract_field(doc, 0, field)?;
    Some(doc[start..end].to_vec())
}

/// Returns `Some(())` when the field is present and non-null.
/// Used by `count(field)` accumulator to count non-null values.