Class InMemoryFileSystem

src/Common/PlatformFileSystem_test.cpp:557–997

This implementation is in no-way a complete or full-featured, but is a prototype to showcase the potential of FileSystem abstraction.

// This implementation is in no-way a complete or full-featured,
// but is a prototype to showcase the potential of FileSystem abstraction.
class InMemoryFileSystem : public TestFileSystem {
 public:
  using Files = std::map<fs::path, std::string>;
  using Directories = std::set<fs::path>;
  using OpenOutputFiles = std::map<const std::ostream *, fs::path>;

  explicit InMemoryFileSystem(const fs::path &cwd) : TestFileSystem(cwd) {
    FileSystem::setInstance(this);

    fs::path d1 = cwd;
    fs::path d2;
    while (d1 != d2) {
      m_directories.emplace(d1);
      d2 = d1;
      d1 = d1.parent_path();
    }
  }

  std::istream &openInput(const fs::path &filepath,
                          std::ios_base::openmode mode) override {
    if (!filepath.is_absolute()) {
      return m_nullInputStream;
    }

    std::scoped_lock<std::mutex> lock(m_inputStreamsMutex);
    Files::const_iterator it1 = m_files.find(filepath);
    if (it1 == m_files.end()) {
      return m_nullInputStream;
    }

    std::pair<InputStreams::iterator, bool> it2 =
        m_inputStreams.emplace(new std::istringstream(it1->second));

    return **it2.first;
  }

  bool close(std::istream &strm) override {
    std::scoped_lock<std::mutex> lock(m_inputStreamsMutex);

    InputStreams::const_iterator it =
        m_inputStreams.find((std::istringstream *)&strm);
    if (it != m_inputStreams.end()) {
      m_inputStreams.erase(it);
      return true;
    }

    return false;
  }

  std::ostream &openOutput(const fs::path &filepath,
                           std::ios_base::openmode mode) override {
    if (!filepath.is_absolute()) {
      return m_nullOutputStream;
    }

    std::scoped_lock<std::mutex> lock(m_outputStreamsMutex);

    std::string content;