registry.h revision 731df977c0511bca2206b5f333555b1205ff1f43 
1// Copyright (c) 2010 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_WIN_REGISTRY_H_
6#define BASE_WIN_REGISTRY_H_
7#pragma once
8
9#include <windows.h>
10#include <string>
11
12#include "base/basictypes.h"
13
14namespace base {
15namespace win {
16
17// Utility class to read, write and manipulate the Windows Registry.
18// Registry vocabulary primer: a "key" is like a folder, in which there
19// are "values", which are <name, data> pairs, with an associated data type.
20class RegKey {
21 public:
22  RegKey();
23  RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access);
24  ~RegKey();
25
26  bool Create(HKEY rootkey, const wchar_t* subkey, REGSAM access);
27
28  bool CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
29                             DWORD* disposition, REGSAM access);
30
31  bool Open(HKEY rootkey, const wchar_t* subkey, REGSAM access);
32
33  // Creates a subkey or open it if it already exists.
34  bool CreateKey(const wchar_t* name, REGSAM access);
35
36  // Opens a subkey
37  bool OpenKey(const wchar_t* name, REGSAM access);
38
39  void Close();
40
41  DWORD ValueCount();
42
43  // Determine the nth value's name.
44  bool ReadName(int index, std::wstring* name);
45
46  // True while the key is valid.
47  bool Valid() const { return key_ != NULL; }
48
49  // Kill a key and everything that live below it; please be careful when using
50  // it.
51  bool DeleteKey(const wchar_t* name);
52
53  // Deletes a single value within the key.
54  bool DeleteValue(const wchar_t* name);
55
56  bool ValueExists(const wchar_t* name);
57
58  bool ReadValue(const wchar_t* name, void* data, DWORD* dsize, DWORD* dtype);
59  bool ReadValue(const wchar_t* name, std::wstring* value);
60  bool ReadValueDW(const wchar_t* name, DWORD* value);
61
62  bool WriteValue(const wchar_t* name, const void* data, DWORD dsize,
63                  DWORD dtype);
64  bool WriteValue(const wchar_t* name, const wchar_t* value);
65  bool WriteValue(const wchar_t* name, DWORD value);
66
67  // Starts watching the key to see if any of its values have changed.
68  // The key must have been opened with the KEY_NOTIFY access privelege.
69  bool StartWatching();
70
71  // If StartWatching hasn't been called, always returns false.
72  // Otherwise, returns true if anything under the key has changed.
73  // This can't be const because the |watch_event_| may be refreshed.
74  bool HasChanged();
75
76  // Will automatically be called by destructor if not manually called
77  // beforehand.  Returns true if it was watching, false otherwise.
78  bool StopWatching();
79
80  inline bool IsWatching() const { return watch_event_ != 0; }
81  HANDLE watch_event() const { return watch_event_; }
82  HKEY Handle() const { return key_; }
83
84 private:
85  HKEY key_;  // The registry key being iterated.
86  HANDLE watch_event_;
87
88  DISALLOW_COPY_AND_ASSIGN(RegKey);
89};
90
91// Iterates the entries found in a particular folder on the registry.
92// For this application I happen to know I wont need data size larger
93// than MAX_PATH, but in real life this wouldn't neccessarily be
94// adequate.
95class RegistryValueIterator {
96 public:
97  RegistryValueIterator(HKEY root_key, const wchar_t* folder_key);
98
99  ~RegistryValueIterator();
100
101  DWORD ValueCount() const;
102
103  // True while the iterator is valid.
104  bool Valid() const;
105
106  // Advances to the next registry entry.
107  void operator++();
108
109  const wchar_t* Name() const { return name_; }
110  const wchar_t* Value() const { return value_; }
111  DWORD ValueSize() const { return value_size_; }
112  DWORD Type() const { return type_; }
113
114  int Index() const { return index_; }
115
116 private:
117  // Read in the current values.
118  bool Read();
119
120  // The registry key being iterated.
121  HKEY key_;
122
123  // Current index of the iteration.
124  int index_;
125
126  // Current values.
127  wchar_t name_[MAX_PATH];
128  wchar_t value_[MAX_PATH];
129  DWORD value_size_;
130  DWORD type_;
131
132  DISALLOW_COPY_AND_ASSIGN(RegistryValueIterator);
133};
134
135class RegistryKeyIterator {
136 public:
137  RegistryKeyIterator(HKEY root_key, const wchar_t* folder_key);
138
139  ~RegistryKeyIterator();
140
141  DWORD SubkeyCount() const;
142
143  // True while the iterator is valid.
144  bool Valid() const;
145
146  // Advances to the next entry in the folder.
147  void operator++();
148
149  const wchar_t* Name() const { return name_; }
150
151  int Index() const { return index_; }
152
153 private:
154  // Read in the current values.
155  bool Read();
156
157  // The registry key being iterated.
158  HKEY key_;
159
160  // Current index of the iteration.
161  int index_;
162
163  wchar_t name_[MAX_PATH];
164
165  DISALLOW_COPY_AND_ASSIGN(RegistryKeyIterator);
166};
167
168}  // namespace win
169}  // namespace base
170
171#endif  // BASE_WIN_REGISTRY_H_
172