Add FilePath::FinalExtension and RemoveFinalExtension

base/files/file_path.cc

 // Copyright 2008 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/files/file_path.h"
 
 #include <ctype.h>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 
 namespace base {
 
 #if defined(FILE_PATH_USES_WIN_SEPARATORS)
 const FilePath::CharType FilePath::kSeparators[] = FILE_PATH_LITERAL("\\/");
 #else  // FILE_PATH_USES_WIN_SEPARATORS
 const FilePath::CharType FilePath::kSeparators[] = FILE_PATH_LITERAL("/");
 #endif  // FILE_PATH_USES_WIN_SEPARATORS
 
 const FilePath::CharType FilePath::kCurrentDirectory[] = FILE_PATH_LITERAL(".");
+const FilePath::CharType FilePath::kParentDirectory[] = FILE_PATH_LITERAL("..");
+const FilePath::CharType FilePath::kExtensionSeparator = FILE_PATH_LITERAL('.');
 
 typedef FilePath::StringType StringType;
 
 namespace {
 
 const FilePath::CharType kStringTerminator = FILE_PATH_LITERAL('\0');
 
 // If this FilePath contains a drive letter specification, returns the
 // position of the last character of the drive letter specification,
 // otherwise returns npos.  This can only be true on Windows, when a pathname
@@ skipping 152 matching lines @@
       new_path.path_.find_last_of(kSeparators, StringType::npos,
                                   arraysize(kSeparators) - 1);
   if (last_separator != StringType::npos &&
       last_separator < new_path.path_.length() - 1) {
     new_path.path_.erase(0, last_separator + 1);
   }
 
   return new_path;
 }
 
+StringType FilePath::FinalExtension() const {
+  StringType base(BaseName().value());
+  // Special case "." and ".."
+  if (base == FilePath::kCurrentDirectory || base == FilePath::kParentDirectory)
+    return StringType();
+  const StringType::size_type dot = base.rfind(FilePath::kExtensionSeparator);
+  if (dot == StringType::npos)
+    return StringType();
+
+  return base.substr(dot, StringType::npos);
+}
+
+FilePath FilePath::RemoveFinalExtension() const {
+  StringType extension = FinalExtension();
+  if (FinalExtension().empty())
+    return *this;
+  return FilePath(path_.substr(0, path_.size() - extension.size()));
+}
+
 FilePath FilePath::Append(const StringType& component) const {
   const StringType* appended = &component;
   StringType without_nuls;
 
   StringType::size_type nul_pos = component.find(kStringTerminator);
   if (nul_pos != StringType::npos) {
     without_nuls = component.substr(0, nul_pos);
     appended = &without_nuls;
   }
 
@@ skipping 59 matching lines @@
       last_stripped = pos;
     }
   }
 }
 
 }  // namespace base
 
 void PrintTo(const base::FilePath& path, std::ostream* out) {
   *out << path.value().c_str();
 }