Function extract_str

nodedb-query/src/msgpack_scan/aggregate_helpers.rs:41–47

Extract a display string from `field`, or evaluate `expr` if provided. Returns `None` when the field is absent.

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

/// Extract a display string from `field`, or evaluate `expr` if provided.
/// Returns `None` when the field is absent.
pub fn extract_str(doc: &[u8], field: &str, expr: Option<&SqlExpr>) -> Option<String> {
    if let Some(expr) = expr {
        return Some(value_ops::value_to_display_string(&eval_expr(doc, expr)?));
    }
    let (start, _end) = extract_field(doc, 0, field)?;
    read_str(doc, start).map(|s| s.to_string())
}

/// Extract a field as `Value`.  Uses direct msgpack→Value for scalars;
/// falls back to full document decode only for complex types.