Fix Path::expand, close #7.

Author: liuxy600

src/FS.cpp

@@ -258,56 +258,59 @@ bool Path::rename (const std::string& new_name)
 // ~      --> /home/user
 // ~foo/x --> /home/foo/s
 // ~/x    --> /home/foo/x
+// .      --> $PWD
 // ./x    --> $PWD/x
 // x      --> $PWD/x
 std::string Path::expand (const std::string& in)
 {
   std::string copy = in;
 
-  auto tilde = copy.find ('~');
   std::string::size_type slash;
 
-  if (tilde != std::string::npos)
+  if (in.empty ())
+  { }
+
+  else if (in.front () == '~')
   {
-    const char *home = getenv("HOME");
+    const char* home = getenv ("HOME");
     if (home == nullptr)
     {
       struct passwd* pw = getpwuid (getuid ());
       home = pw->pw_dir;
     }
 
     // Convert: ~ --> /home/user
-    if (copy.length () == 1)
+    if (in.length () == 1)
       copy = home;
 
     // Convert: ~/x --> /home/user/x
-    else if (copy.length () > tilde + 1 &&
-             copy[tilde + 1] == '/')
-    {
-      copy.replace (tilde, 1, home);
-    }
+    else if (in.at (1) == '/')
+      copy = home + in.substr (1);
 
     // Convert: ~foo/x --> /home/foo/x
-    else if ((slash = copy.find ('/', tilde)) != std::string::npos)
+    else if ((slash = in.find ('/', 1)) != std::string::npos)
     {
-      std::string name = copy.substr (tilde + 1, slash - tilde - 1);
+      std::string name = in.substr (1, slash - 1);
       struct passwd* pw = getpwnam (name.c_str ());
       if (pw)
-        copy.replace (tilde, slash - tilde, pw->pw_dir);
+        copy = pw->pw_dir + in.substr (slash);
     }
   }
 
   // Relative paths
-  else if (in.length () > 2 &&
-           in.substr (0, 2) == "./")
-  {
-    copy = Directory::cwd () + in.substr (1);
-  }
-  else if (in.length () > 1 &&
-           in[0] != '.' &&
-           in[0] != '/')
+  else if (in.front () != '/')
   {
-    copy = Directory::cwd () + '/' + in;
+    // Convert: ., ./ --> $PWD
+    if (in == ".")
+      copy = Directory::cwd ();
+
+    // Convert: ./x --> $PWD/x
+    else if (in.substr (0, 2) == "./")
+      copy = Directory::cwd () + in.substr (1);
+
+    // Convert: x --> $PWD/x
+    else
+      copy = Directory::cwd () + '/' + in;
   }
 
   return copy;

test/fs.t.cpp

@@ -33,7 +33,7 @@
 
 int main (int, char**)
 {
-  UnitTest t (117);
+  UnitTest t (120);
 
   try
   {
@@ -99,6 +99,9 @@ int main (int, char**)
     // static std::string expand (const std::string&);
     t.ok (Path::expand ("~") != "~", "Path::expand ~ != ~");
     t.ok (Path::expand ("~/") != "~/", "Path::expand ~/ != ~/");
+    t.ok (Path::expand (".") != ".", "Path::expand . != .");
+    t.ok (Path::expand ("./") != "./", "Path::expand ./ != ./");
+    t.ok (Path::expand (".a") != ".a", "Path::expand .a != .a");
 
     // static std::vector <std::string> glob (const std::string&);
     std::vector <std::string> out = Path::glob ("/tmp");