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 temporary key named by temp_name
  38   // under the temporary test key path. There is no need to randomize
  39   // |override_name|, as a random parent key is generated. Multiple overrides to
  40   // the same hive are not supported and lead to undefined behavior.
  41   void OverrideRegistry(HKEY override, const base::string16& override_name);
  42
  43  private:
  44   friend class RegistryOverrideManagerTest;
  45
  46   // Keeps track of one override.
  47   class ScopedRegistryKeyOverride {
  48    public:
  49     ScopedRegistryKeyOverride(HKEY override, const base::string16& key_path);
  50     ~ScopedRegistryKeyOverride();
  51
  52    private:
  53     HKEY override_;
  54     base::win::RegKey temp_key_;
  55
  56     DISALLOW_COPY_AND_ASSIGN(ScopedRegistryKeyOverride);
  57   };
  58
  59   // Used for testing only.
  60   RegistryOverrideManager(const base::Time& timestamp,
  61                           const base::string16& test_key_root);
  62
  63   base::Time timestamp_;
  64   base::string16 guid_;
  65
  66   base::string16 test_key_root_;
  67   ScopedVector<ScopedRegistryKeyOverride> overrides_;
  68
  69   DISALLOW_COPY_AND_ASSIGN(RegistryOverrideManager);
  70 };
  71
  72 // Generates a temporary key path that will be eventually deleted
  73 // automatically if the process crashes.
  74 base::string16 GenerateTempKeyPath();
  75
  76 }  // namespace registry_util
  77
  78 #endif  // BASE_TEST_TEST_REG_UTIL_H_