object-introspection/oi/Features.cpp

/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#include "Features.h"

#include <map>
#include <numeric>
#include <stdexcept>

namespace ObjectIntrospection {
namespace {

std::string_view featureHelp(Feature f) {
  switch (f) {
    case Feature::ChaseRawPointers:
      return "Chase raw pointers in the probed object.";
    case Feature::PackStructs:
      return "Pack structs.";
    case Feature::GenPaddingStats:
      return "Generate statistics on padding of structures.";
    case Feature::CaptureThriftIsset:
      return "Capture isset data for Thrift object.";
    case Feature::TypeGraph:
      return "Use Type Graph for code generation (CodeGen V2).";
    case Feature::TypedDataSegment:
      return "Use Typed Data Segment in generated code.";
    case Feature::GenJitDebug:
      return "Generate debug information for the JIT object.";
    case Feature::JitLogging:
      return "Log information from the JIT code for debugging.";
    case Feature::PolymorphicInheritance:
      return "Follow polymorphic inheritance hierarchies in the probed object.";
    case Feature::JitTiming:
      return "Instrument the JIT code with timing for performance testing.";

    case Feature::UnknownFeature:
      throw std::runtime_error("should not ask for help for UnknownFeature!");
  }
}

}  // namespace

Feature featureFromStr(std::string_view str) {
  static const std::map<std::string_view, Feature> nameMap = {
#define X(name, str) {str, Feature::name},
      OI_FEATURE_LIST
#undef X
  };

  if (auto search = nameMap.find(str); search != nameMap.end()) {
    return search->second;
  }
  return Feature::UnknownFeature;
}

const char* featureToStr(Feature f) {
  switch (f) {
#define X(name, str)  \
  case Feature::name: \
    return str;
    OI_FEATURE_LIST
#undef X

    default:
      return "UnknownFeature";
  }
}

void featuresHelp(std::ostream& out) {
  out << "FEATURES SUMMARY" << std::endl;

  size_t longestName = std::accumulate(
      allFeatures.begin(), allFeatures.end(), 0, [](size_t acc, Feature f) {
        return std::max(acc, std::string_view(featureToStr(f)).size());
      });

  for (Feature f : allFeatures) {
    std::string_view name(featureToStr(f));

    out << "  " << name << std::string(longestName - name.size() + 2, ' ')
        << featureHelp(f) << std::endl;
  }
}

}  // namespace ObjectIntrospection