Function merge_ops

atomic-core/src/merge/three_way.rs:319–363

Combine two non-conflicting edit scripts and produce merged content bytes.

(base: &[MergeToken], left_ops: &[EditOp], right_ops: &[EditOp])

/// Combine two non-conflicting edit scripts and produce merged content bytes.
fn merge_ops(base: &[MergeToken], left_ops: &[EditOp], right_ops: &[EditOp]) -> Vec<u8> {
    // Build per-index action maps.
    let left_action = build_action_map(left_ops);
    let right_action = build_action_map(right_ops);

    let left_inserts = insert_positions(left_ops);
    let right_inserts = insert_positions(right_ops);

    let mut result: Vec<u8> = Vec::new();

    // Handle insertions before the first token.
    emit_inserts(&left_inserts, usize::MAX, &mut result);
    emit_inserts(&right_inserts, usize::MAX, &mut result);

    for (i, base_token) in base.iter().enumerate() {
        // Determine what to emit for base token i.
        let left_act = left_action.get(&i);
        let right_act = right_action.get(&i);

        match (left_act, right_act) {
            // Both sides kept (or neither touched) — emit base.
            (None, None) => {
                result.extend_from_slice(&base_token.content);
            }
            // Only left modified.
            (Some(action), None) => {
                emit_action(action, base_token, &mut result);
            }
            // Only right modified.
            (None, Some(action)) => {
                emit_action(action, base_token, &mut result);
            }
            // Both modified identically (already verified no conflict).
            (Some(action), Some(_)) => {
                emit_action(action, base_token, &mut result);
            }
        }

        // Emit any insertions that follow base token i.
        emit_inserts(&left_inserts, i, &mut result);
        emit_inserts(&right_inserts, i, &mut result);
    }

    result
}

/// Action on a single base token: either replace or delete.
#[derive(Debug, Clone)]