add getters for xdg directories

src/filesystem.cpp

@@ -99,6 +99,76 @@ boost::filesystem::path filesystem::get_home_path() noexcept {
   return boost::filesystem::path();
 }
 
+bool filesystem::create_missing_path(const boost::filesystem::path &path) noexcept {
+  boost::system::error_code ec;
+  if(!boost::filesystem::exists(path, ec)) {
+    if(!boost::filesystem::create_directories(path, ec)) {
+      return (!ec);
+    }
+  }
+  return false;
+}
+
+boost::filesystem::path filesystem::get_environment_path(const char *variable) noexcept {
+  try {
+    auto ptr = std::getenv(variable);
+    if(ptr) {
+      return boost::filesystem::path(ptr);
+    }
+  }
+  catch(...) {
+  }
+  return boost::filesystem::path();
+}
+
+const boost::filesystem::path &filesystem::get_data_path() noexcept {
+  static boost::filesystem::path data_path;
+  if(!data_path.empty())
+    return data_path;
+
+  const auto env_path = get_environment_path("XDG_DATA_HOME");
+
+  if(env_path.empty()) {
+    data_path = get_home_path() / ".local" / "share";
+  }
+
+  create_missing_path(data_path);
+
+  return data_path;
+}
+
+const boost::filesystem::path &filesystem::get_config_path() noexcept {
+  static boost::filesystem::path config_path;
+  if(!config_path.empty())
+    return config_path;
+
+  const auto env_path = get_environment_path("XDG_CONFIG_HOME");
+
+  if(env_path.empty()) {
+    config_path = get_home_path() / ".config";
+  }
+
+  create_missing_path(config_path);
+
+  return config_path;
+}
+
+const boost::filesystem::path &filesystem::get_cache_path() noexcept {
+  static boost::filesystem::path cache_path;
+  if(!cache_path.empty())
+    return cache_path;
+
+  const auto env_path = get_environment_path("XDG_CACHE_HOME");
+
+  if(env_path.empty()) {
+    cache_path = get_home_path() / ".cache";
+  }
+
+  create_missing_path(cache_path);
+
+  return cache_path;
+}
+
 boost::filesystem::path filesystem::get_short_path(const boost::filesystem::path &path) noexcept {
 #ifdef _WIN32
   return path;

src/filesystem.hpp

@@ -4,6 +4,10 @@
 #include <vector>
 
 class filesystem {
+private:
+  static bool create_missing_path(const boost::filesystem::path &path) noexcept;
+  static boost::filesystem::path get_environment_path(const char *variable) noexcept;
+
 public:
   static std::string read(const std::string &path);
   static std::string read(const boost::filesystem::path &path) { return read(path.string()); }
@@ -16,7 +20,19 @@ public:
   static std::string escape_argument(const std::string &argument);
   static std::string unescape_argument(const std::string &argument);
 
+  /// Return the $HOME environment variable. If HOME is not set, then AppData
+  /// is returned. If neither HOME or AppData is set, then an empty path is
+  /// returned.
   static boost::filesystem::path get_home_path() noexcept;
+  /// Return the XDG_CONFIG_HOME environment variable if set. If
+  /// XDG_CONFIG_HOME is not set the default $HOME/.config is returned.
+  static const boost::filesystem::path &get_config_path() noexcept;
+  /// Return the XDG_CACHE_HOME environment variable if set. If XDG_CACHE_HOME
+  /// is not set the default $HOME/.cache is returned.
+  static const boost::filesystem::path &get_cache_path() noexcept;
+  /// Return the XDG_DATA_HOME environment variable if set. If XDG_DATA_HOME
+  /// is not set the default $HOME/.local/share is returned.
+  static const boost::filesystem::path &get_data_path() noexcept;
   /// Replaces home path with ~
   static boost::filesystem::path get_short_path(const boost::filesystem::path &path) noexcept;
   /// Replaces ~ with home path (boost::filesystem does not recognize ~)

tests/filesystem_test.cpp

@@ -91,4 +91,22 @@ int main() {
     g_assert(uri == "file:///ro%20ot/te%20st%C3%A6%C3%B8%C3%A5.txt");
     g_assert(path == filesystem::get_path_from_uri(uri));
   }
+
+  {
+    auto path = filesystem::get_cache_path();
+    path = filesystem::get_short_path(path);
+    g_assert(path == "~/.cache");
+  }
+
+  {
+    auto path = filesystem::get_data_path();
+    path = filesystem::get_short_path(path);
+    g_assert(path == "~/.local/share");
+  }
+
+  {
+    auto path = filesystem::get_config_path();
+    path = filesystem::get_short_path(path);
+    g_assert(path == "~/.config");
+  }
 }