util.{hh,cc}: Split out users.{hh,cc}

Change-Id: I1bd92479a2cb7e5c2c2e1541b80474adb05ea0df

src/libutil/users.hh

@@ -0,0 +1,61 @@
+#pragma once
+///@file
+
+#include "types.hh"
+
+#include <sys/types.h>
+
+namespace nix {
+
+std::string getUserName();
+
+/**
+ * @return the given user's home directory from /etc/passwd.
+ */
+Path getHomeOf(uid_t userId);
+
+/**
+ * @return $HOME or the user's home directory from /etc/passwd.
+ */
+Path getHome();
+
+/**
+ * @return $XDG_CACHE_HOME or $HOME/.cache.
+ */
+Path getCacheDir();
+
+/**
+ * @return $XDG_CONFIG_HOME or $HOME/.config.
+ */
+Path getConfigDir();
+
+/**
+ * @return the directories to search for user configuration files
+ */
+std::vector<Path> getConfigDirs();
+
+/**
+ * @return $XDG_DATA_HOME or $HOME/.local/share.
+ */
+Path getDataDir();
+
+/**
+ * @return $XDG_STATE_HOME or $HOME/.local/state.
+ *
+ * @note Not to be confused with settings.nixStateDir.
+ */
+Path getStateDir();
+
+/**
+ * Create $XDG_STATE_HOME/nix or $HOME/.local/state/nix, and return
+ * the path to it.
+ * @note Not to be confused with settings.nixStateDir.
+ */
+Path createNixStateDir();
+
+/**
+ * Perform tilde expansion on a path.
+ */
+std::string expandTilde(std::string_view path);
+
+}