src/common/cmd_utils.h

// Copyright (C) 2019 The Android Open Source Project
//
// 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.

#ifndef IORAP_SRC_COMMON_CMD_UTILS_H_
#define IORAP_SRC_COMMON_CMD_UTILS_H_

#include <android-base/parsebool.h>
#include <android-base/properties.h>

#include <iostream>
#include <sstream>
#include <optional>
#include <vector>

namespace iorap::common {
// Create execve-compatible argv.
// The lifetime is tied to that of vector.
inline std::unique_ptr<const char*[]> VecToArgv(const char* program_name,
                                              const std::vector<std::string>& vector) {
  // include program name in argv[0]
  // include a NULL sentinel in the end.
  std::unique_ptr<const char*[]> ptr{new const char*[vector.size() + 2]};

  // program name
  ptr[0] = program_name;

  // all the argv
  for (size_t i = 0; i < vector.size(); ++i) {
    ptr[i+1] = vector[i].c_str();
  }

  // null sentinel
  ptr[vector.size() + 1] = nullptr;

  return ptr;
}

// Appends an args to the argv.
template <class T>
void AppendArgs(std::vector<std::string>& argv,
                const T& value) {
  std::stringstream ss;
  ss << value;
  argv.push_back(ss.str());
}

// Appends an args to the argv.
template <class T, class T2>
void AppendArgs(std::vector<std::string>& argv,
                const T& value,
                const T2& value2) {
  AppendArgs(argv, value);
  AppendArgs(argv, value2);
}

// Appends a named argument to the argv.
//
// For example if <name> is "--property" and <value> is int(200):
// the string "--property=200" is appended to the argv.
template <class T, class T2>
void AppendNamedArg(std::vector<std::string>& argv,
                    const T& name,
                    const T2& value) {
  std::stringstream ss;
  ss << name;
  ss << "=";
  ss << value;

  argv.push_back(ss.str());
}

// Appends args from a vector to the argv repeatedly to argv.
//
// For example, if <args> is "--timestamp" and <values> is [100, 200].
// The "--timestamp 100" and "--timestamp 200" are appended.
template <class T>
void AppendArgsRepeatedly(std::vector<std::string>& argv,
                          std::string args,
                          const std::vector<T>& values) {
  for (const T& v : values) {
     AppendArgs(argv, args, v);
  }
}

// Appends args from a vector to the argv repeatedly to argv.
//
// For example, if values is [input1.pb, input2.pb],
// then the "input1.pb" and "input2.pb" are appended.
template <class T>
void AppendArgsRepeatedly(std::vector<std::string>& argv,
                          const std::vector<T>& values) {
  for (const T& v : values) {
     AppendArgs(argv, v);
  }
}

// Appends a named argument to the argv repeatedly with different values.
//
// For example if <name> is "--property" and <value> is [int(200), int(400)]:
// the strings "--property=200" and "--property=400" are both appended to the argv.
template <class T, class T2>
void AppendNamedArgRepeatedly(std::vector<std::string>& argv,
                              const T& name,
                              const std::vector<T2>& values) {
  for (const T2& v :values) {
    AppendNamedArg(argv, name, v);
  }
}

// Get the value of the property.
// Firstly, try to find the environment variable. If it does not exist,
// try to get the property. If neither, use the default value..
//
// For example, for prop foo.bar.baz, it will first check for
// FOO_BAR_BAZ environment variable.
inline std::string GetEnvOrProperty(const std::string& prop, const std::string& default_val) {
  std::string env_str = prop;
  // a.b.c -> a_b_c
  std::replace(env_str.begin(), env_str.end(), '.', '_');
  // a_b_c -> A_B_C
  std::transform(env_str.begin(), env_str.end(), env_str.begin(), ::toupper);
  char *env = getenv(env_str.c_str());
  if (env) {
    return std::string(env);
  }
  return ::android::base::GetProperty(prop, default_val);
}

// Get the boolean value of the property.
// Firstly, try to find the environment variable. If it does not exist,
// try to get the property. If neither, use the default value..
//
// For example, for prop foo.bar.baz, it will first check for
// FOO_BAR_BAZ environment variable.
inline bool GetBoolEnvOrProperty(const std::string& prop, bool default_val) {
  std::string env_str = prop;
  // a.b.c -> a_b_c
  std::replace(env_str.begin(), env_str.end(), '.', '_');
  // a_b_c -> A_B_C
  std::transform(env_str.begin(), env_str.end(), env_str.begin(), ::toupper);
  char *env = getenv(env_str.c_str());
  if (env) {
    using ::android::base::ParseBoolResult;

    switch (::android::base::ParseBool(env)) {
      case ParseBoolResult::kError:
        break;
      case ParseBoolResult::kFalse:
        return false;
      case ParseBoolResult::kTrue:
        return true;
    }
  }
  return ::android::base::GetBoolProperty(prop, default_val);
}

}   // namespace iorap::common

#endif  // IORAP_SRC_COMMON_CMD_UTILS_H_