shell/common/switches.cc

// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>

// Include once for the default enum definition.
#include "flutter/shell/common/switches.h"

#undef SHELL_COMMON_SWITCHES_H_

struct SwitchDesc {
  shell::Switch sw;
  const char* flag;
  const char* help;
};

#undef DEF_SWITCHES_START
#undef DEF_SWITCH
#undef DEF_SWITCHES_END

// clang-format off
#define DEF_SWITCHES_START static const struct SwitchDesc gSwitchDescs[] = {
#define DEF_SWITCH(p_swtch, p_flag, p_help) \
  { .sw = shell::Switch:: p_swtch, .flag = p_flag, .help = p_help },
#define DEF_SWITCHES_END };
// clang-format on

// Include again for struct definition.
#include "flutter/shell/common/switches.h"

namespace shell {

void PrintUsage(const std::string& executable_name) {
  std::cerr << std::endl << "  " << executable_name << std::endl << std::endl;

  std::cerr << "Available Flags:" << std::endl;

  const uint32_t column_width = 80;

  const uint32_t flags_count = static_cast<uint32_t>(Switch::Sentinel);

  uint32_t max_width = 2;
  for (uint32_t i = 0; i < flags_count; i++) {
    auto desc = gSwitchDescs[i];
    max_width = std::max<uint32_t>(strlen(desc.flag) + 2, max_width);
  }

  const uint32_t help_width = column_width - max_width - 3;

  std::cerr << std::string(column_width, '-') << std::endl;
  for (uint32_t i = 0; i < flags_count; i++) {
    auto desc = gSwitchDescs[i];

    std::cerr << std::setw(max_width)
              << std::string("--") + std::string(desc.flag) << " : ";

    std::istringstream stream(desc.help);
    int32_t remaining = help_width;

    std::string word;
    while (stream >> word && remaining > 0) {
      remaining -= (word.size() + 1);
      if (remaining <= 0) {
        std::cerr << std::endl
                  << std::string(max_width, ' ') << "   " << word << " ";
        remaining = help_width;
      } else {
        std::cerr << word << " ";
      }
    }

    std::cerr << std::endl;
  }
  std::cerr << std::string(column_width, '-') << std::endl;
}

const char* FlagForSwitch(Switch swtch) {
  for (uint32_t i = 0; i < static_cast<uint32_t>(Switch::Sentinel); i++) {
    if (gSwitchDescs[i].sw == swtch) {
      return gSwitchDescs[i].flag;
    }
  }
  return nullptr;
}

}  // namespace shell