Add implementations of various extension related methods (derived from file_u...

base/file_path.cc

 // Copyright (c) 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/file_path.h"
 #include "base/file_util.h"
 #include "base/logging.h"
 
 // These includes are just for the *Hack functions, and should be removed
 // when those functions are removed.
 #include "base/string_piece.h"
 #include "base/string_util.h"
 #include "base/sys_string_conversions.h"
 
 #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('.');
+
+
 namespace {
 
 // 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
 // begins with a letter followed by a colon.  On other platforms, this always
 // returns npos.
 FilePath::StringType::size_type FindDriveLetter(
     const FilePath::StringType& path) {
 #if defined(FILE_PATH_USES_DRIVE_LETTERS)
   // This is dependent on an ASCII-based character set, but that's a
   // reasonable assumption.  iswalpha can be too inclusive here.
   if (path.length() >= 2 && path[1] == L':' &&
       ((path[0] >= L'A' && path[0] <= L'Z') ||
        (path[0] >= L'a' && path[0] <= L'z'))) {
     return 1;
   }
+#endif  // FILE_PATH_USES_DRIVE_LETTERS
   return FilePath::StringType::npos;
-#else  // FILE_PATH_USES_DRIVE_LETTERS
-  return FilePath::StringType::npos;
-#endif  // FILE_PATH_USES_DRIVE_LETTERS
 }
 
 bool IsPathAbsolute(const FilePath::StringType& path) {
 #if defined(FILE_PATH_USES_DRIVE_LETTERS)
   FilePath::StringType::size_type letter = FindDriveLetter(path);
   if (letter != FilePath::StringType::npos) {
     // Look for a separator right after the drive specification.
     return path.length() > letter + 1 &&
         FilePath::IsSeparator(path[letter + 1]);
   }
@@ skipping 74 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;
 }
 
-FilePath FilePath::Append(const FilePath::StringType& component) const {
+FilePath::StringType FilePath::Extension() const {
+  // BaseName() calls StripTrailingSeparators, so cases like /foo.baz/// work.
+  StringType base = BaseName().value();
+
+  // Special case "." and ".."
+  if (base == kCurrentDirectory || base == kParentDirectory)
+    return StringType();
+
+  const StringType::size_type last_dot = base.rfind(kExtensionSeparator);
+  if (last_dot == StringType::npos)
+    return StringType();
+  return StringType(base, last_dot);
+}
+
+FilePath FilePath::RemoveExtension() const {
+  StringType ext = Extension();
+  // It's important to check Extension() since that verifies that the
+  // kExtensionSeparator actually appeared in the last path component.
+  if (ext.empty())
+    return FilePath(path_);
+  // Since Extension() verified that the extension is in fact in the last path
+  // component, this substr will effectively strip trailing separators.
+  const StringType::size_type last_dot = path_.rfind(kExtensionSeparator);
+  return FilePath(path_.substr(0, last_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())
+    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::ReplaceExtension(const StringType& extension) const {
+  if (path_.empty())
+    return FilePath();
+
+  StringType base = BaseName().value();
+  if (base.empty())
+    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);
+  return FilePath(str);
+}
+
+FilePath FilePath::Append(const StringType& component) const {
   DCHECK(!IsPathAbsolute(component));
   if (path_.compare(kCurrentDirectory) == 0) {
     // Append normally doesn't do any normalization, but as a special case,
     // when appending to kCurrentDirectory, just return a new path for the
     // component argument.  Appending component to kCurrentDirectory would
     // serve no purpose other than needlessly lengthening the path, and
     // it's likely in practice to wind up with FilePath objects containing
     // only kCurrentDirectory when calling DirName on a single relative path
     // component.
     return FilePath(component);
@@ skipping 99 matching lines @@
        --pos) {
     // If the string only has two separators and they're at the beginning,
     // don't strip them, unless the string began with more than two separators.
     if (pos != start + 1 || last_stripped == start + 2 ||
         !IsSeparator(path_[start - 1])) {
       path_.resize(pos - 1);
       last_stripped = pos;
     }
   }
 }