Function ApplyAliasMap

be/src/service/query-profile-redaction.cc:239–281

Applies a full alias map to a text blob in a single left-to-right pass.

// Applies a full alias map to a text blob in a single left-to-right pass.
static Status ApplyAliasMap(const unordered_map<string, string>& alias_map,
    const string_view& text, string* output) {
  DCHECK(output != nullptr);
  if (alias_map.empty()) {
    *output = string(text);
    return Status::OK();
  }

  const auto entries = GetSortedReplacementEntries(alias_map);

  string result;
  result.reserve(text.size());

  size_t i = 0;
  while (i < text.size()) {
    bool matched = false;
    for (const auto& [from, to] : entries) {
      if (from.empty() || text.size() - i < from.size()) continue;
      if (text.compare(i, from.size(), from) != 0) continue;

      bool start_boundary_ok = (i == 0) || !IsIdentifierChar(text[i - 1]);
      if (!start_boundary_ok && IsEscapedJsonChar(text, i - 1)) {
        start_boundary_ok = true;
      }
      const size_t after_idx = i + from.size();
      const bool end_boundary_ok =
          (after_idx == text.size()) || !IsIdentifierChar(text[after_idx]);
      if (!start_boundary_ok || !end_boundary_ok) continue;

      result.append(to.data(), to.size());
      i += from.size();
      matched = true;
      break;
    }
    if (!matched) {
      result.push_back(text[i]);
      ++i;
    }
  }

  *output = move(result);
  return Status::OK();
}

// Extracts the analyzed query section from a plan text block.
static string ExtractAnalyzedQueryFromPlanText(const string_view& plan_text) {