build-system-toy/command_builder.h

#pragma once

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

#include "types.h"

namespace build {

  class command_builder {
  private:
    indent_t indent_;
    std::stringstream buffer_;

  public:
    command_builder(std::string const & cmd, int indent = 0);

    template <typename T> command_builder && operator<<(T const & value) &&;
    template <typename T> command_builder & operator<<(T const & value) &;
    template <typename T>
    command_builder & operator<<(std::vector<T> const & value) &;

    int execute() const;

  private:
    template <typename T> void write(T const & value) { buffer_ << value; }
    void write(version const & vers);
    void write(source_file const & file);
    void write(output_file const & file);
  };

  command_builder::command_builder(std::string const & cmd, int indent)
      : indent_{indent}, buffer_() {
    buffer_ << cmd;
  }

  template <typename T>
  command_builder && command_builder::operator<<(T const & value) && {
    return std::move((*this) << value);
  }

  template <typename T>
  command_builder & command_builder::operator<<(T const & value) & {
    buffer_ << ' ';
    write(value);
    return *this;
  }

  template <typename T>
  command_builder &
  command_builder::operator<<(std::vector<T> const & value) & {
    for (T const & v : value) {
      (*this) << v;
    }
    return *this;
  }

  void command_builder::write(version const & vers) {
    switch (vers) {
    case version::cxx11:
      buffer_ << ' ' << "-std=c++11";
      break;
    case version::cxx14:
      buffer_ << ' ' << "-std=c++14";
      break;
    case version::cxx17:
      buffer_ << ' ' << "-std=c++17";
      break;
    case none:
      break;
    }
  }

  void command_builder::write(source_file const & file) {
    buffer_ << " -c " << file.get();
  }

  void command_builder::write(output_file const & file) {
    buffer_ << " -o " << file.get();
  }

  std::ostream & operator<<(std::ostream & os, indent_t const & value) {
    for (int i = 0; i < value.value; ++i) {
      os << "  ";
    }
    return os;
  }

  int command_builder::execute() const {
    std::string cmdstr = buffer_.str();
    // TODO(samjaffe): Not sure this belongs here, so much as command_builder
    // should take a formatter object (including things like color config)
    std::cout << indent_ << cmdstr << std::endl;
    return std::system(cmdstr.c_str());
  }

}