utils: add join_paths + tests

lib/utils/mu-utils-file.cc

@@ -78,13 +78,13 @@ Mu::play (const std::string& path)
 	argv[0] = program_path->c_str();
 	argv[1] = path.c_str();
 	argv[2] = nullptr;
-	
+
 	GError *err{};
 	if (!g_spawn_async ({}, (gchar**)&argv, {}, G_SPAWN_SEARCH_PATH, maybe_setsid,
 			    {}, {}, &err))
 		return Err(Error::Code::File, &err/*consumes*/, "failed to open '%s' with '%s'",
 			   path. c_str(), program_path->c_str());
-	
+
 	return Ok();
 }
 
@@ -109,7 +109,7 @@ Mu::determine_dtype (const std::string& path, bool use_lstat)
 {
 	int res;
 	struct stat statbuf{};
-	
+
 	if (use_lstat)
 		res = ::lstat(path.c_str(), &statbuf);
 	else
@@ -257,6 +257,17 @@ test_program_in_path(void)
 	g_assert_true(!!program_in_path("ls"));
 }
 
+static void
+test_join_paths()
+{
+
+	assert_equal(join_paths(), "");
+	assert_equal(join_paths("a"), "a");
+	assert_equal(join_paths("a", "b"), "a/b");
+	assert_equal(join_paths("/a/b///c/d//", "e"), "/a/b/c/d/e");
+}
+
+
 
 int
 main(int argc, char* argv[])
@@ -272,12 +283,12 @@ main(int argc, char* argv[])
 			test_check_dir_03);
 	g_test_add_func("/utils/check-dir-04",
 			test_check_dir_04);
-
 	g_test_add_func("/utils/determine-dtype-with-lstat",
 			test_determine_dtype_with_lstat);
-	
 	g_test_add_func("/utils/program-in-path",
 			test_program_in_path);
+	g_test_add_func("/utils/join-paths",
+			test_join_paths);
 
 	return g_test_run();
 }

lib/utils/mu-utils-file.hh

@@ -24,8 +24,8 @@
 #include <cinttypes>
 #include <sys/stat.h>
 
-#include <utils/mu-sexp.hh>
 #include <utils/mu-option.hh>
+#include <utils/mu-regex.hh>
 
 namespace Mu {
 
@@ -43,22 +43,22 @@ namespace Mu {
  */
 Result<void> play(const std::string& path);
 
-/** 
+/**
  * Find program in PATH
- * 
+ *
  * @param name the name of the program
- * 
+ *
  * @return either the full path to program, or Nothing if not found.
- */	
+ */
 Option<std::string> program_in_path(const std::string& name);
-	
+
-/** 
+/**
  * Check if the directory has the given attributes
- * 
+ *
  * @param path path to dir
  * @param readable is it readable?
  * @param writeable is it writable?
- * 
+ *
  * @return true if is is a directory with given attributes; false otherwise.
  */
 bool check_dir(const std::string& path, bool readable, bool writeable);
@@ -72,8 +72,8 @@ bool check_dir(const std::string& path, bool readable, bool writeable);
  * @return
  */
 std::string canonicalize_filename(const std::string& path, const std::string& relative_to);
-	
+
-/*	
+/*
  * for OSs with out support for direntry->d_type, like Solaris
  */
 #ifndef DT_UNKNOWN
@@ -108,7 +108,7 @@ enum {
  *
  * @return DT_REG, DT_DIR, DT_LNK, or DT_UNKNOWN (other values are not supported
  * currently)
- */	
+ */
 uint8_t determine_dtype(const std::string& path, bool use_lstat);
 
 
@@ -135,7 +135,28 @@ enum struct RuntimePath {
  * @return the path name
  */
 std::string runtime_path(RuntimePath path, const std::string& muhome="");
+/**
+ * Join  path components into a path (with '/')
+ *
+ * @param s a string-convertible value
+ * @param args 0 or more string-convertible values
+ *
+ * @return the path
+ */
+static inline std::string join_paths() { return {}; }
+template<typename S, typename...Args>
+std::string join_paths(S&& s, Args...args) {
 
+	static std::string sepa{"/"};
+	auto&& str{std::string{std::forward<S>(s)}};
+	if (auto&& rest{join_paths(std::forward<Args>(args)...)}; !rest.empty())
+		str += (sepa + rest);
+
+	static auto rx = Regex::make("//*").value();
+	return rx.replace(str, sepa);
 }
-#endif /* MU_UTILS_FILE_HH__ */
 
+
+} // namespace Mu
+
+#endif /* MU_UTILS_FILE_HH__ */