paths: add system path queries

CMakeLists.txt

@@ -494,6 +494,7 @@ list (
     parse/value.hpp
     parse/si.cpp
     parse/si.hpp
+    paths.cpp
     paths.hpp
     platform.hpp
     point.cpp
@@ -752,6 +753,7 @@ if (TESTS)
         parse/value
         parse/time
         parse/si
+        paths
         point
         polynomial
         pool

paths.cpp

@@ -0,0 +1,3 @@
+#include "./paths.hpp"
+
+

paths.hpp

@@ -3,15 +3,24 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2020, Danny Robson <danny@nerdcruft.net>
+ * Copyright 2022, Danny Robson <danny@nerdcruft.net>
  */
 
 #pragma once
 
 #include <filesystem>
+#include <optional>
 
 
+///////////////////////////////////////////////////////////////////////////////
 namespace cruft::paths {
+    /// Return the path to the system's temporary directory.
+    std::filesystem::path temp (void);
+
+
+    /// Expand paths that contain platform specific variables
+    ///
+    /// eg, "$TMPDIR/foo" and "%HOMEPATH%/foo"
     std::filesystem::path
     expand (std::filesystem::path const&);
 }

paths_posix.cpp

@@ -16,6 +16,17 @@
 #include <wordexp.h>
 
 
+///////////////////////////////////////////////////////////////////////////////
+std::filesystem::path
+cruft::paths::temp (void)
+{
+    if (char const *tmpdir = getenv ("TMPDIR"); tmpdir)
+        return tmpdir;
+
+    return "/tmp";
+}
+
+
 ///////////////////////////////////////////////////////////////////////////////
 std::filesystem::path
 cruft::paths::expand (std::filesystem::path const &val)
@@ -29,4 +40,4 @@ cruft::paths::expand (std::filesystem::path const &val)
 
     CHECK_EQ (words.we_offs, 0u);
     return words.we_wordv[0];
-}
+}

test/paths.cpp

@@ -0,0 +1,15 @@
+#include <cruft/util/tap.hpp>
+
+#include <cruft/util/paths.hpp>
+#include <cruft/util/fs/scoped.hpp>
+#include <cruft/util/fs/tmp.hpp>
+
+
+int main (int, char**)
+{
+    cruft::TAP::logger tap;
+
+    tap.expect (!cruft::paths::temp ().empty (), "temp directory is not empty");
+
+    return tap.status ();
+}