Add an AddExtension() method in FilePath

base/file_path.cc

 // 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.
 
 #include "base/file_path.h"
 
 #include <string.h>
 #include <algorithm>
 
 #include "base/basictypes.h"
@@ skipping 141 matching lines @@
       (last_separator == StringType::npos ||
       penultimate_dot > last_separator) &&
       last_dot - penultimate_dot <= 5U &&
       last_dot - penultimate_dot > 1U) {
     return penultimate_dot;
   }
 
   return last_dot;
 }
 
+// Returns true if path is "", ".", or "..".
+bool IsEmptyOrSpecialCase(const StringType& path) {
+  // Special cases "", ".", and ".."
+  if (path.empty() || path == FilePath::kCurrentDirectory ||
+      path == FilePath::kParentDirectory) {
+    return true;
+  }
+
+  return false;
+}
+
 }  // namespace
 
 FilePath::FilePath() {
 }
 
 FilePath::FilePath(const FilePath& that) : path_(that.path_) {
 }
 
 FilePath::FilePath(const StringType& path) : path_(path) {
 }
@@ skipping 199 matching lines @@
   return FilePath(path_.substr(0, dot));
 }
 
 FilePath FilePath::InsertBeforeExtension(const StringType& suffix) const {
   if (suffix.empty())
     return FilePath(path_);
 
   if (path_.empty())
     return FilePath();
 
-  StringType base = BaseName().value();
-  if (base.empty())
+  if (IsEmptyOrSpecialCase(BaseName().value()))
     return FilePath();
-  if (*(base.end() - 1) == kExtensionSeparator) {
-    // Special case "." and ".."
-    if (base == kCurrentDirectory || base == kParentDirectory) {
-      return FilePath();
-    }
-  }
 
   StringType ext = Extension();
   StringType ret = RemoveExtension().value();
   ret.append(suffix);
   ret.append(ext);
   return FilePath(ret);
 }
 
 FilePath FilePath::InsertBeforeExtensionASCII(const base::StringPiece& suffix)
     const {
   DCHECK(IsStringASCII(suffix));
 #if defined(OS_WIN)
   return InsertBeforeExtension(ASCIIToUTF16(suffix.as_string()));
 #elif defined(OS_POSIX)
   return InsertBeforeExtension(suffix.as_string());
 #endif
 }
 
+FilePath FilePath::AddExtension(const StringType& extension) const {
+  if (path_.empty())

[Mark Mentovai, 2012/04/21 17:02:00]

This check is redundant because IsEmptyOrSpecialCase will be true if path_ is
empty, right?

+    return FilePath();
+
+  if (IsEmptyOrSpecialCase(BaseName().value()))
+    return FilePath();
+
+  // If the new extension is "" or ".", then just return the current FilePath.
+  if (extension.empty() || extension == StringType(1, kExtensionSeparator))
+    return *this;
+
+  StringType str = path_;
+  if (extension[0] != kExtensionSeparator &&
+      *(str.end() - 1) != kExtensionSeparator) {
+    str.append(1, kExtensionSeparator);
+  }
+  str.append(extension);
+  return FilePath(str);
+}
+
 FilePath FilePath::ReplaceExtension(const StringType& extension) const {
   if (path_.empty())

[Mark Mentovai, 2012/04/21 17:02:00]

Same question applies here.

     return FilePath();
 
-  StringType base = BaseName().value();
-  if (base.empty())
+  if (IsEmptyOrSpecialCase(BaseName().value()))
     return FilePath();
-  if (*(base.end() - 1) == kExtensionSeparator) {
-    // Special case "." and ".."
-    if (base == kCurrentDirectory || base == kParentDirectory) {
-      return FilePath();
-    }
-  }
 
   FilePath no_ext = RemoveExtension();
   // If the new extension is "" or ".", then just remove the current extension.
   if (extension.empty() || extension == StringType(1, kExtensionSeparator))
     return no_ext;
 
   StringType str = no_ext.value();
   if (extension[0] != kExtensionSeparator)
     str.append(1, kExtensionSeparator);
   str.append(extension);
@@ skipping 783 matching lines @@
 #if defined(FILE_PATH_USES_WIN_SEPARATORS)
   StringType copy = path_;
   for (size_t i = 1; i < arraysize(kSeparators); ++i) {
     std::replace(copy.begin(), copy.end(), kSeparators[i], kSeparators[0]);
   }
   return FilePath(copy);
 #else
   return *this;
 #endif
 }