Program Listing for File log_stream.h

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// SPDX-FileCopyrightText: 2024 The OpenSn Authors <https://open-sn.github.io/opensn/>
// SPDX-License-Identifier: MIT

#pragma once

#include <iostream>
#include <sstream>
#include "stringstream_color.h"

namespace opensn
{

/// Log stream for adding header information to a string stream.
class LogStream : public std::stringstream
{
private:
  std::ostream* log_stream_;
  std::string log_header_;
  const bool dummy_;
  bool use_color_;

public:
  LogStream(std::ostream* output_stream,
            std::string header,
            bool dummy_flag = false,
            bool use_color = false)
    : log_stream_(output_stream),
      log_header_(std::move(header)),
      dummy_(dummy_flag),
      use_color_(use_color)
  {
  }

  LogStream(const LogStream&) = delete;
  LogStream& operator=(const LogStream&) = delete;

  ~LogStream() noexcept override
  {
    if (dummy_)
      return;

    try
    {
      std::string content = this->str();
      if (content.empty())
        return;

      std::istringstream iss(content);
      std::string line;
      std::string oline;
      std::string reset_str = use_color_ ? StringStreamColor(StringStreamColorCode::RESET) : "";
      while (std::getline(iss, line))
      {
        oline += log_header_;
        oline += line;
        oline += reset_str;
        oline += "\n";
      }

      if (!oline.empty())
        *log_stream_ << oline << std::flush;
    }
    catch (...) // NOLINT(bugprone-empty-catch)
    {
      // No exceptions escape the destructor...
    }
  }
};

struct DummyStream : public std::ostream
{
  struct DummyStreamBuffer : std::streambuf
  {
    int overflow(int c) override { return c; };
  } buffer;

  DummyStream() : std::ostream(&buffer) {}
  ~DummyStream() override = default;
};

} // namespace opensn