ENH: add optional checkGzip parameter to fileName::type(..) method

- this simplifies use of a unified test for directory or file.

      fileName::Type what = myfile.type(true, true);
      if (what == FILE) ...
      if (what == DIRECTORY) ...

- Use distinct bit values for fileName::Type, for possible use in
  the future.

- related to issue #1121, since we need a more flexible way of
  expanding file or directory.

  An alternative would be to add checkGzip to Foam::exists() and
  Foam::type() functions, but that would make the code there more
  confusing and in the fileHandler classes.

src/OpenFOAM/primitives/strings/fileName/fileName.C

@@ -201,9 +201,21 @@ Foam::fileName::fileName(std::initializer_list<word> list)
 
 // * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
 
-Foam::fileName::Type Foam::fileName::type(const bool followLink) const
+Foam::fileName::Type Foam::fileName::type
+(
+    bool followLink,
+    bool checkGzip
+) const
 {
-    return ::Foam::type(*this, followLink);
+    Type t = ::Foam::type(*this, followLink);
+
+    if (checkGzip && (Type::UNDEFINED == t) && size())
+    {
+        // Also check for gzip file?
+        t = ::Foam::type(*this + ".gz", followLink);
+    }
+
+    return t;
 }
 
 

src/OpenFOAM/primitives/strings/fileName/fileName.H

@@ -80,13 +80,13 @@ class fileName
 
 public:
 
-    //- Enumerations to handle file types and modes.
+    //- Enumerations to handle directory entry types.
     enum Type
     {
-        UNDEFINED,  //!< Undefined file type.
-        FILE,       //!< A file
-        DIRECTORY,  //!< A directory
-        LINK        //!< A symlink
+        UNDEFINED = 0,  //!< Undefined type
+        FILE = 1,       //!< A file
+        DIRECTORY = 2,  //!< A directory
+        LINK = 4        //!< A symlink
     };
 
 
@@ -201,9 +201,13 @@ public:
 
     // Interrogation
 
-        //- Return the file type: FILE, DIRECTORY, LINK or UNDEFINED.
-        //  LINK is only returned if followLink=false
-        Type type(const bool followLink = true) const;
+        //- Return the directory entry type:
+        //- UNDEFINED, FILE, DIRECTORY (or LINK).
+        //
+        //  \param followLink when false it will return LINK for a symlink
+        //     rather than following it.
+        //  \param checkGzip add an additional test for a gzip FILE
+        Type type(bool followLink=true, bool checkGzip=false) const;
 
         //- Return true if string starts with a '/'
         inline static bool isAbsolute(const std::string& str);