net/base/platform_mime_util_win.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/base/platform_mime_util.h"
   6
   7 #include <string>
   8
   9 #include "base/strings/utf_string_conversions.h"
  10 #include "base/win/registry.h"
  11
  12 namespace net {
  13
  14 bool PlatformMimeUtil::GetPlatformMimeTypeFromExtension(
  15     const base::FilePath::StringType& ext, std::string* result) const {
  16   // check windows registry for file extension's mime type (registry key
  17   // names are not case-sensitive).
  18   std::wstring value, key = L"." + ext;
  19   base::win::RegKey(HKEY_CLASSES_ROOT, key.c_str(), KEY_READ).ReadValue(
  20       L"Content Type", &value);
  21   if (!value.empty()) {
  22     *result = WideToUTF8(value);
  23     return true;
  24   }
  25   return false;
  26 }
  27
  28 bool PlatformMimeUtil::GetPreferredExtensionForMimeType(
  29     const std::string& mime_type, base::FilePath::StringType* ext) const {
  30   std::wstring key(L"MIME\\Database\\Content Type\\" + UTF8ToWide(mime_type));
  31   if (base::win::RegKey(HKEY_CLASSES_ROOT, key.c_str(), KEY_READ).ReadValue(
  32           L"Extension", ext) != ERROR_SUCCESS) {
  33     return false;
  34   }
  35   // Strip off the leading dot, this should always be the case.
  36   if (!ext->empty() && ext->at(0) == L'.')
  37     ext->erase(ext->begin());
  38
  39   return true;
  40 }
  41
  42 void PlatformMimeUtil::GetPlatformExtensionsForMimeType(
  43     const std::string& mime_type,
  44     base::hash_set<base::FilePath::StringType>* extensions) const {
  45   // Multiple extensions could have the given mime type specified as their types
  46   // in their 'HKCR\.<extension>\Content Type' keys. Iterating all the HKCR
  47   // entries, though, is wildly impractical. Cheat by returning just the
  48   // preferred extension.
  49   base::FilePath::StringType ext;
  50   if (GetPreferredExtensionForMimeType(mime_type, &ext))
  51     extensions->insert(ext);
  52 }
  53
  54 }  // namespace net