Add path::current(), path::parent()

6 files changed, 97 insertions, 51 deletions

diff --git a/butl/filesystem.cxx b/butl/filesystem.cxx
index 424e361..0643938 100644
--- a/butl/filesystem.cxx
+++ b/butl/filesystem.cxx
@@ -531,14 +531,17 @@ namespace butl
       errno = 0;
       if (struct dirent* de = readdir (h_))
       {
-        const char* n (de->d_name);
+        // We can accept some overhead for '.' and '..' (relying on short
+        // string optimization) in favor of a more compact code.
+        //
+        path p (de->d_name);
 
         // Skip '.' and '..'.
         //
-        if (n[0] == '.' && (n[1] == '\0' || (n[1] == '.' && n[2] == '\0')))
+       if (p.current () || p.parent ())
           continue;
 
-        e_.p_ = path (n);
+        e_.p_ = move (p);
         e_.t_ = d_type<struct dirent> (de, nullptr);
         e_.lt_ = entry_type::unknown;
       }
@@ -665,14 +668,17 @@ namespace butl
 
       if (r)
       {
-        const char* n (fi.name);
+        // We can accept some overhead for '.' and '..' (relying on short
+        // string optimization) in favor of a more compact code.
+        //
+        path p (fi.name);
 
         // Skip '.' and '..'.
         //
-        if (n[0] == '.' && (n[1] == '\0' || (n[1] == '.' && n[2] == '\0')))
+        if (p.current () || p.parent ())
           continue;
 
-        e_.p_ = path (n);
+        e_.p_ = move (p);
 
         // We do not support symlinks at the moment.
         //
diff --git a/butl/path b/butl/path
index 2e243ff..726bbe6 100644
--- a/butl/path
+++ b/butl/path
@@ -121,6 +121,30 @@ namespace butl
 #endif
     }
 
+    static bool
+    current (const string_type& s)
+    {
+      return current (s.c_str (), s.size ());
+    }
+
+    static bool
+    current (const C* s, size_type n)
+    {
+      return n == 1 && s[0] == '.';
+    }
+
+    static bool
+    parent (const string_type& s)
+    {
+      return parent (s.c_str (), s.size ());
+    }
+
+    static bool
+    parent (const C* s, size_type n)
+    {
+      return n == 2 && s[0] == '.' && s[1] == '.';
+    }
+
     static size_type
     find_separator (string_type const& s,
                     size_type pos = 0,
@@ -276,16 +300,16 @@ namespace butl
     // the underlying OS errors.
     //
     static string_type
-    current ();
+    current_directory ();
 
     static void
-    current (string_type const&);
+    current_directory (string_type const&);
 
     // Return the user home directory. Throw std::system_error to report the
     // underlying OS errors.
     //
     static string_type
-    home ();
+    home_directory ();
 
     // Return the temporary directory. Throw std::system_error to report the
     // underlying OS errors.
@@ -548,16 +572,16 @@ namespace butl
     // the underlying OS errors.
     //
     static dir_type
-    current () {return dir_type (traits::current ());}
+    current_directory () {return dir_type (traits::current_directory ());}
 
     static void
-    current (basic_path const&);
+    current_directory (basic_path const&);
 
     // Return the user home directory. Throw std::system_error to report the
     // underlying OS errors.
     //
     static dir_type
-    home () {return dir_type (traits::home ());}
+    home_directory () {return dir_type (traits::home_directory ());}
 
     // Return the temporary directory. Throw std::system_error to report the
     // underlying OS errors.
@@ -603,6 +627,20 @@ namespace butl
     bool
     root () const;
 
+    // The following predicates return true for the "." and ".." paths,
+    // respectively. Note that the result doesn't depend on the presence or
+    // spelling of the trailing directory separator.
+    //
+    // Also note that the path must literally match the specified values rather
+    // than be semantically current or parent. For example for paths "foo/.."
+    // or "bar/../.." the predicates return false.
+    //
+    bool
+    current () const;
+
+    bool
+    parent () const;
+
     // Test, based on the presence/absence of the trailing separator, if the
     // path is to a directory.
     //
diff --git a/butl/path.cxx b/butl/path.cxx
index 03d4b1f..d77f9a4 100644
--- a/butl/path.cxx
+++ b/butl/path.cxx
@@ -60,7 +60,7 @@ namespace butl
 
   template <>
   LIBBUTL_EXPORT path_traits<char>::string_type path_traits<char>::
-  current ()
+  current_directory ()
   {
 #ifdef _WIN32
     char cwd[_MAX_PATH];
@@ -78,7 +78,7 @@ namespace butl
 
   template <>
   LIBBUTL_EXPORT void path_traits<char>::
-  current (string_type const& s)
+  current_directory (string_type const& s)
   {
 #ifdef _WIN32
     if (_chdir (s.c_str ()) != 0)
@@ -173,10 +173,10 @@ namespace butl
 
   template <>
   LIBBUTL_EXPORT path_traits<char>::string_type path_traits<char>::
-  home ()
+  home_directory ()
   {
 #ifndef _WIN32
-    return butl::home ();
+    return home ();
 #else
     // Could be set by, e.g., MSYS and Cygwin shells.
     //
@@ -223,7 +223,7 @@ namespace butl
 
   template <>
   LIBBUTL_EXPORT path_traits<wchar_t>::string_type path_traits<wchar_t>::
-  current ()
+  current_directory ()
   {
 #ifdef _WIN32
     wchar_t wcwd[_MAX_PATH];
@@ -245,7 +245,7 @@ namespace butl
 
   template <>
   LIBBUTL_EXPORT void path_traits<wchar_t>::
-  current (string_type const& s)
+  current_directory (string_type const& s)
   {
 #ifdef _WIN32
     if (_wchdir (s.c_str ()) != 0)
@@ -305,11 +305,11 @@ namespace butl
 
   template <>
   LIBBUTL_EXPORT path_traits<wchar_t>::string_type path_traits<wchar_t>::
-  home ()
+  home_directory ()
   {
 #ifndef _WIN32
     wchar_t d[PATH_MAX];
-    size_t r (mbstowcs (d, butl::home ().c_str (), PATH_MAX));
+    size_t r (mbstowcs (d, home ().c_str (), PATH_MAX));
 
     if (r == size_t (-1))
       throw system_error (EINVAL, system_category ());
diff --git a/butl/path.ixx b/butl/path.ixx
index c87a376..b1212f4 100644
--- a/butl/path.ixx
+++ b/butl/path.ixx
@@ -88,6 +88,20 @@ namespace butl
 
   template <typename C, typename K>
   inline bool basic_path<C, K>::
+  current () const
+  {
+    return traits::current (this->path_);
+  }
+
+  template <typename C, typename K>
+  inline bool basic_path<C, K>::
+  parent () const
+  {
+    return traits::parent (this->path_);
+  }
+
+  template <typename C, typename K>
+  inline bool basic_path<C, K>::
   root () const
   {
     const string_type& s (this->path_);
@@ -232,7 +246,7 @@ namespace butl
   complete ()
   {
     if (relative ())
-      *this = current () / *this;
+      *this = current_directory () / *this;
 
     return *this;
   }
diff --git a/butl/path.txx b/butl/path.txx
index 0cdaf5b..7c46dbe 100644
--- a/butl/path.txx
+++ b/butl/path.txx
@@ -193,10 +193,7 @@ namespace butl
       if (!tsep)
       {
         const string_type& l (ps.back ());
-        size_type ln (l.size ());
-
-        if ((ln == 1 && l[0] == '.') ||
-            (ln == 2 && l[0] == '.' && l[1] == '.'))
+        if (traits::current (l) || traits::parent (l))
           tsep = true;
       }
     }
@@ -208,30 +205,21 @@ namespace butl
     for (typename paths::iterator i (ps.begin ()), e (ps.end ()); i != e; ++i)
     {
       string_type& s (*i);
-      size_type n (s.size ());
 
-      if (n == 1 && s[0] == '.')
+      if (traits::current (s))
         continue;
 
-      if (n == 2 && s[0] == '.' && s[1] == '.')
+      // If '..' then pop the last directory from r unless it is '..'.
+      //
+      if (traits::parent (s) && !r.empty () && !traits::parent (r.back ()))
       {
-        // Pop the last directory from r unless it is '..'.
+        // Cannot go past the root directory.
         //
-        if (!r.empty ())
-        {
-          string_type const& s1 (r.back ());
+        if (abs && r.size () == 1)
+          throw invalid_basic_path<C> (this->path_);
 
-          if (!(s1.size () == 2 && s1[0] == '.' && s1[1] == '.'))
-          {
-            // Cannot go past the root directory.
-            //
-            if (abs && r.size () == 1)
-              throw invalid_basic_path<C> (this->path_);
-
-            r.pop_back ();
-            continue;
-          }
-        }
+          r.pop_back ();
+          continue;
       }
 
       r.push_back (std::move (s));
@@ -286,7 +274,7 @@ namespace butl
         }
         else if (!cur_empty) // Collapse to canonical current directory.
         {
-          p = ".";
+          p.assign (1, '.');
           ts = 1; // Canonical separator is always first.
         }
         else // Collapse to empty path.
@@ -304,14 +292,14 @@ namespace butl
 
   template <typename C, typename K>
   void basic_path<C, K>::
-  current (basic_path const& p)
+  current_directory (basic_path const& p)
   {
     const string_type& s (p.string ());
 
     if (s.empty ())
       throw invalid_basic_path<char> (s);
 
-    traits::current (s);
+    traits::current_directory (s);
   }
 
   template <typename C>
diff --git a/butl/process.cxx b/butl/process.cxx
index cf4b26d..df9fb1f 100644
--- a/butl/process.cxx
+++ b/butl/process.cxx
@@ -189,7 +189,7 @@ namespace butl
       }
       else
       {
-        const string& d (traits::current ());
+        const string& d (traits::current_directory ());
 
         if (search (d.c_str (), d.size (), true))
           return r;
@@ -507,7 +507,7 @@ namespace butl
       }
       else
       {
-        const string& d (traits::current ());
+        const string& d (traits::current_directory ());
 
         if (search (d.c_str (), d.size (), true)) // Appends extension.
           return r;
@@ -567,7 +567,7 @@ namespace butl
     // idea to prepend .\ for clarity.
     //
     {
-      const string& d (traits::current ());
+      const string& d (traits::current_directory ());
 
       if (search (d.c_str (), d.size ()))
         return r;
@@ -582,8 +582,8 @@ namespace butl
       e = strchr (b, traits::path_separator);
 
       // Empty path (i.e., a double colon or a colon at the beginning or end
-      // of PATH) means search in the current dirrectory. Silently skip
-      // invalid paths.
+      // of PATH) means search in the current directory. Silently skip invalid
+      // paths.
       //
       try
       {