Add an AddExtension() method in FilePath

base/file_path.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // FilePath is a container for pathnames stored in a platform's native string
 // type, providing containers for manipulation in according with the
 // platform's conventions for pathnames.  It supports the following path
 // types:
 //
 //                   POSIX            Windows
@@ skipping 224 matching lines @@
   // Examples:
   // path == "C:\pics\jojo.jpg" suffix == " (1)", returns "C:\pics\jojo (1).jpg"
   // path == "jojo.jpg"         suffix == " (1)", returns "jojo (1).jpg"
   // path == "C:\pics\jojo"     suffix == " (1)", returns "C:\pics\jojo (1)"
   // path == "C:\pics.old\jojo" suffix == " (1)", returns "C:\pics.old\jojo (1)"
   FilePath InsertBeforeExtension(
       const StringType& suffix) const WARN_UNUSED_RESULT;
   FilePath InsertBeforeExtensionASCII(
       const base::StringPiece& suffix) const WARN_UNUSED_RESULT;
 
+  // Adds |extension| to |file_name|. Returns the current FilePath if
+  // |extension| is empty. Returns "" if BaseName() == "." or "..".
+  FilePath AddExtension(

[Mark Mentovai, 2012/04/16 15:54:45]

It’s hard to see why you need to use this without a use case, but why is this
better than ReplaceExtension? Are you planning on having
a.filename.with.multiple.extensions?

[Devlin, 2012/04/17 21:52:49]

The most common instance I've encountered is when using a tempfile generated by
Chrome.  These files can take the form of org.Chromium.abc.xyz (real example:
/tmp/.org.chromium.Chromium.hAlw5V); when we use ReplaceExtension it results in
a different path, and the behavior of using ReplaceExtension can be different
than when passing in a non-temp file.  AddExtension makes it so that there's no
ambiguity.

+      const StringType& extension) const WARN_UNUSED_RESULT;
+
   // Replaces the extension of |file_name| with |extension|.  If |file_name|
-  // does not have an extension, them |extension| is added.  If |extension| is
+  // does not have an extension, then |extension| is added.  If |extension| is
   // empty, then the extension is removed from |file_name|.
   // Returns "" if BaseName() == "." or "..".
   FilePath ReplaceExtension(
       const StringType& extension) const WARN_UNUSED_RESULT;
 
+  // Returns true if BaseName() is "", ".", or "..".
+  bool IsBaseEmptyOrSpecialCase() const;

[Mark Mentovai, 2012/04/16 15:54:45]

Why do you need to expose this?

[Devlin, 2012/04/17 21:52:49]

My original thought was that these instances are fairly common occurrences of
paths people may wish to treat specially (or disallow).  However, I do not have
any concrete examples of when this would be the case; if you feel it better to
be moved to private scope (or within an anonymous namespace in the cc file
only), I'd be fine with that.

[Mark Mentovai, 2012/04/18 20:02:21]

D Cronin wrote:
I’d just hide this in the cc file.

[Devlin, 2012/04/19 00:05:42]

Done.

+
   // Returns true if the file path matches the specified extension. The test is
   // case insensitive. Don't forget the leading period if appropriate.
   bool MatchesExtension(const StringType& extension) const;
 
   // Returns a FilePath by appending a separator and the supplied path
   // component to this object's path.  Append takes care to avoid adding
   // excessive separators if this object's path already ends with a separator.
   // If this object's path is kCurrentDirectory, a new FilePath corresponding
   // only to |component| is returned.  |component| must be a relative path;
   // it is an error to pass an absolute path.
@@ skipping 158 matching lines @@
 
 inline size_t hash_value(const FilePath& f) {
   return hash_value(f.value());
 }
 
 #endif  // COMPILER
 
 }  // namespace BASE_HASH_NAMESPACE
 
 #endif  // BASE_FILE_PATH_H_