base/test/test_reg_util_win.h

   1 // Copyright (c) 2011 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 #ifndef BASE_TEST_TEST_REG_UTIL_H_
   6 #define BASE_TEST_TEST_REG_UTIL_H_
   7
   8 // Registry utility functions used only by tests.
   9
  10 #include "base/basictypes.h"
  11 #include "base/memory/scoped_vector.h"
  12 #include "base/strings/string16.h"
  13 #include "base/time/time.h"
  14 #include "base/win/registry.h"
  15
  16 namespace registry_util {
  17
  18 // Allows a test to easily override registry hives so that it can start from a
  19 // known good state, or make sure to not leave any side effects once the test
  20 // completes. This supports parallel tests. All the overrides are scoped to the
  21 // lifetime of the override manager. Destroy the manager to undo the overrides.
  22 //
  23 // Overridden hives use keys stored at, for instance:
  24 //   HKCU\Software\Chromium\TempTestKeys\
  25 //       13028145911617809$02AB211C-CF73-478D-8D91-618E11998AED
  26 // The key path are comprises of:
  27 //   - The test key root, HKCU\Software\Chromium\TempTestKeys\
  28 //   - The base::Time::ToInternalValue of the creation time. This is used to
  29 //     delete stale keys left over from crashed tests.
  30 //   - A GUID used for preventing name collisions (although unlikely) between
  31 //     two RegistryOverrideManagers created with the same timestamp.
  32 class RegistryOverrideManager {
  33  public:
  34   RegistryOverrideManager();
  35   ~RegistryOverrideManager();
  36
  37   // Override the given registry hive using a randomly generated temporary key.
  38   // Multiple overrides to the same hive are not supported and lead to undefined
  39   // behavior.
  40   void OverrideRegistry(HKEY override);
  41
  42  private:
  43   friend class RegistryOverrideManagerTest;
  44
  45   // Keeps track of one override.
  46   class ScopedRegistryKeyOverride {
  47    public:
  48     ScopedRegistryKeyOverride(HKEY override, const base::string16& key_path);
  49     ~ScopedRegistryKeyOverride();
  50
  51    private:
  52     HKEY override_;
  53     base::win::RegKey temp_key_;
  54
  55     DISALLOW_COPY_AND_ASSIGN(ScopedRegistryKeyOverride);
  56   };
  57
  58   // Used for testing only.
  59   RegistryOverrideManager(const base::Time& timestamp,
  60                           const base::string16& test_key_root);
  61
  62   base::Time timestamp_;
  63   base::string16 guid_;
  64
  65   base::string16 test_key_root_;
  66   ScopedVector<ScopedRegistryKeyOverride> overrides_;
  67
  68   DISALLOW_COPY_AND_ASSIGN(RegistryOverrideManager);
  69 };
  70
  71 // Generates a temporary key path that will be eventually deleted
  72 // automatically if the process crashes.
  73 base::string16 GenerateTempKeyPath();
  74
  75 }  // namespace registry_util
  76
  77 #endif  // BASE_TEST_TEST_REG_UTIL_H_