static Subtree ts_parser__reuse_node()

in lib/src/parser.c [540:608]

• 61 lines of code
• 14 McCabe index (conditional complexity)

static Subtree ts_parser__reuse_node(TSParser *self, StackVersion version,
                                     TSStateId *state, uint32_t position,
                                     Subtree last_external_token, TableEntry *table_entry) {
  Subtree result;
  while ((result = reusable_node_tree(&self->reusable_node)).ptr) {
    uint32_t byte_offset = reusable_node_byte_offset(&self->reusable_node);
    uint32_t end_byte_offset = byte_offset + ts_subtree_total_bytes(result);

    if (byte_offset > position) {
      LOG("before_reusable_node symbol:%s", TREE_NAME(result));
      break;
    }

    if (byte_offset < position) {
      LOG("past_reusable_node symbol:%s", TREE_NAME(result));
      if (end_byte_offset <= position || !reusable_node_descend(&self->reusable_node)) {
        reusable_node_advance(&self->reusable_node);
      }
      continue;
    }

    if (!ts_subtree_external_scanner_state_eq(self->reusable_node.last_external_token, last_external_token)) {
      LOG("reusable_node_has_different_external_scanner_state symbol:%s", TREE_NAME(result));
      reusable_node_advance(&self->reusable_node);
      continue;
    }

    const char *reason = NULL;
    if (ts_subtree_has_changes(result)) {
      reason = "has_changes";
    } else if (ts_subtree_is_error(result)) {
      reason = "is_error";
    } else if (ts_subtree_missing(result)) {
      reason = "is_missing";
    } else if (ts_subtree_is_fragile(result)) {
      reason = "is_fragile";
    } else if (ts_parser__has_included_range_difference(self, byte_offset, end_byte_offset)) {
      reason = "contains_different_included_range";
    }

    if (reason) {
      LOG("cant_reuse_node_%s tree:%s", reason, TREE_NAME(result));
      if (!reusable_node_descend(&self->reusable_node)) {
        reusable_node_advance(&self->reusable_node);
        ts_parser__breakdown_top_of_stack(self, version);
        *state = ts_stack_state(self->stack, version);
      }
      continue;
    }

    TSSymbol leaf_symbol = ts_subtree_leaf_symbol(result);
    ts_language_table_entry(self->language, *state, leaf_symbol, table_entry);
    if (!ts_parser__can_reuse_first_leaf(self, *state, result, table_entry)) {
      LOG(
        "cant_reuse_node symbol:%s, first_leaf_symbol:%s",
        TREE_NAME(result),
        SYM_NAME(leaf_symbol)
      );
      reusable_node_advance_past_leaf(&self->reusable_node);
      break;
    }

    LOG("reuse_node symbol:%s", TREE_NAME(result));
    ts_subtree_retain(result);
    return result;
  }

  return NULL_SUBTREE;
}