Function parse

src/linux/perf.cpp:405–477

Try<hashmap<string, mesos::PerfStatistics>> parse(
    const string& output)
{
  hashmap<string, mesos::PerfStatistics> statistics;

  foreach (const string& line, strings::tokenize(output, "\n")) {
    Try<Sample> sample = Sample::parse(line);

    if (sample.isError()) {
      return Error("Failed to parse perf sample line '" + line + "': " +
                   sample.error());
    }

    // Some additional metrics (e.g. stalled cycles per instruction)
    // are printed without an event. Ignore them.
    if (sample->event.empty()) {
      continue;
    }

    if (!statistics.contains(sample->cgroup)) {
      statistics.put(sample->cgroup, mesos::PerfStatistics());
    }

    const google::protobuf::Reflection* reflection =
      statistics[sample->cgroup].GetReflection();
    const google::protobuf::FieldDescriptor* field =
      statistics[sample->cgroup].GetDescriptor()->FindFieldByName(
          sample->event);

    if (field == nullptr) {
      return Error("Unexpected event '" + sample->event + "'"
                   " in perf output at line: " + line);
    }

    if (sample->value == "<not supported>") {
      LOG(WARNING) << "Unsupported perf counter, ignoring: " << line;
      continue;
    }

    switch (field->type()) {
      case google::protobuf::FieldDescriptor::TYPE_DOUBLE: {
        Try<double> number = (sample->value == "<not counted>")
            ?  0
            : numify<double>(sample->value);

        if (number.isError()) {
          return Error("Unable to parse perf value at line: " + line);
        }

        reflection->SetDouble(&(
            statistics[sample->cgroup]), field, number.get());
        break;
      }
      case google::protobuf::FieldDescriptor::TYPE_UINT64: {
        Try<uint64_t> number = (sample->value == "<not counted>")
            ?  0
            : numify<uint64_t>(sample->value);