Make path::normalize() to preserve ./, invalidate paths starting with \, / on Windows

4 files changed, 47 insertions, 16 deletions

diff --git a/butl/buildfile b/butl/buildfile
index 5c5aae3..6e259c8 100644
--- a/butl/buildfile
+++ b/butl/buildfile
@@ -21,6 +21,7 @@ lib{butl}:                               \
 {hxx     txx    }{ prefix-map          } \
 {hxx ixx     cxx}{ process             } \
 {hxx         cxx}{ sha256              } \
+{hxx            }{ small-vector        } \
 {hxx     txx    }{ string-table        } \
 {hxx         cxx}{ timestamp           } \
 {hxx         cxx}{ triplet             } \
diff --git a/butl/path b/butl/path
index 2a32c70..2e243ff 100644
--- a/butl/path
+++ b/butl/path
@@ -808,7 +808,11 @@ namespace butl
     // Normalize the path and return *this. Normalization involves collapsing
     // the '.' and '..'  directories if possible, collapsing multiple
     // directory separators, and converting all directory separators to the
-    // canonical form.
+    // canonical form. If cur_empty is true then collapse relative paths
+    // representing the current directory (for example, '.', './', 'foo/..')
+    // to an empty path. Otherwise convert it to the canonical form (./ on
+    // POSIX systems). Note that a non-empty path cannot become an empty one
+    // in the latter case.
     //
     // If actual is true, then for case-insensitive filesystems obtain the
     // actual spelling of the path. Only an absolute path can be actualized.
@@ -818,7 +822,7 @@ namespace butl
     // etc.) are returned in their actual spelling.
     //
     basic_path&
-    normalize (bool actual = false);
+    normalize (bool actual = false, bool cur_empty = false);
 
     // Make the path absolute using the current directory unless it is already
     // absolute. Return *this.
diff --git a/butl/path.txx b/butl/path.txx
index 5bcaea0..0cdaf5b 100644
--- a/butl/path.txx
+++ b/butl/path.txx
@@ -147,7 +147,7 @@ namespace butl
 
   template <typename C, typename K>
   basic_path<C, K>& basic_path<C, K>::
-  normalize (bool actual)
+  normalize (bool actual, bool cur_empty)
   {
     if (empty ())
       return *this;
@@ -273,12 +273,24 @@ namespace butl
         p += traits::directory_separator;
     }
 
-    if (tsep && (!p.empty () || abs)) // Distinguish "/"-empty and "."-empty.
+    if (tsep)
     {
       if (p.empty ())
       {
-        p += traits::directory_separator;
-        ts = -1;
+        // Distinguish "/"-empty and "."-empty.
+        //
+        if (abs)
+        {
+          p += traits::directory_separator;
+          ts = -1;
+        }
+        else if (!cur_empty) // Collapse to canonical current directory.
+        {
+          p = ".";
+          ts = 1; // Canonical separator is always first.
+        }
+        else // Collapse to empty path.
+          ts = 0;
       }
       else
         ts = 1; // Canonical separator is always first.
@@ -313,11 +325,11 @@ namespace butl
 
 #ifdef _WIN32
     // We do not support any special Windows path name notations like in C:abc,
-    // \\?\c:\abc, \\server\abc and \\?\UNC\server\abc (more about them at
-    // https://msdn.microsoft.com/en-us/library/windows/desktop/aa365247.aspx).
+    // /, \, /abc, \abc, \\?\c:\abc, \\server\abc and \\?\UNC\server\abc (more
+    // about them in "Naming Files, Paths, and Namespaces" MSDN article).
     //
     if ((n > 2 && s[1] == ':' && s[2] != '\\' && s[2] != '/') ||
-        (n > 1 && s[0] == '\\' && s[1] == '\\'))
+        (n > 0 && (s[0] == '\\' || s[0] == '/')))
     {
       if (exact)
         return data_type ();
diff --git a/butl/process.cxx b/butl/process.cxx
index c75cfbd..cf4b26d 100644
--- a/butl/process.cxx
+++ b/butl/process.cxx
@@ -171,7 +171,7 @@ namespace butl
       ep = path (move (s)); // Move back into result.
 
       if (norm)
-        ep.normalize (); //@@ NORM
+        ep.normalize ();
 
       return exists (ep.string ().c_str ());
     };
@@ -212,10 +212,17 @@ 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.
+      // of PATH) means search in the current dirrectory. Silently skip
+      // invalid paths.
       //
-      if (search (b, e != nullptr ? e - b : strlen (b)))
-        return r;
+      try
+      {
+        if (search (b, e != nullptr ? e - b : strlen (b)))
+          return r;
+      }
+      catch (const invalid_path&)
+      {
+      }
     }
 
     // If we were given a fallback, try that.
@@ -575,10 +582,17 @@ 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.
+      // of PATH) means search in the current dirrectory. Silently skip
+      // invalid paths.
       //
-      if (search (b, e != nullptr ? e - b : strlen (b)))
-        return r;
+      try
+      {
+        if (search (b, e != nullptr ? e - b : strlen (b)))
+          return r;
+      }
+      catch (const invalid_path&)
+      {
+      }
     }
 
     // Finally, if we were given a fallback, try that. This case is similar to