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// Copyright (c) 2012 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.
#ifndef BASE_WIN_REGISTRY_H_
#define BASE_WIN_REGISTRY_H_
#include <stdint.h>
#include <string>
#include <vector>
#include "base/win/windows_types.h"
#include "base/base_export.h"
#include "base/macros.h"
#include "base/win/object_watcher.h"
#include "base/win/scoped_handle.h"
namespace base {
namespace win {
// Utility class to read, write and manipulate the Windows Registry.
// Registry vocabulary primer: a "key" is like a folder, in which there
// are "values", which are <name, data> pairs, with an associated data type.
//
// Note:
// * ReadValue family of functions guarantee that the out-parameter
// is not touched in case of failure.
// * Functions returning LONG indicate success as ERROR_SUCCESS or an
// error as a (non-zero) win32 error code.
class BASE_EXPORT RegKey {
public:
// Called from the MessageLoop when the key changes.
typedef base::Callback<void()> ChangeCallback;
RegKey();
explicit RegKey(HKEY key);
RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access);
~RegKey();
LONG Create(HKEY rootkey, const wchar_t* subkey, REGSAM access);
LONG CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
DWORD* disposition, REGSAM access);
// Creates a subkey or open it if it already exists.
LONG CreateKey(const wchar_t* name, REGSAM access);
// Opens an existing reg key.
LONG Open(HKEY rootkey, const wchar_t* subkey, REGSAM access);
// Opens an existing reg key, given the relative key name.
LONG OpenKey(const wchar_t* relative_key_name, REGSAM access);
// Closes this reg key.
void Close();
// Replaces the handle of the registry key and takes ownership of the handle.
void Set(HKEY key);
// Transfers ownership away from this object.
HKEY Take();
// Returns false if this key does not have the specified value, or if an error
// occurrs while attempting to access it.
bool HasValue(const wchar_t* value_name) const;
// Returns the number of values for this key, or 0 if the number cannot be
// determined.
DWORD GetValueCount() const;
// Determines the nth value's name.
LONG GetValueNameAt(int index, std::wstring* name) const;
// True while the key is valid.
bool Valid() const { return key_ != NULL; }
// Kills a key and everything that lives below it; please be careful when
// using it.
LONG DeleteKey(const wchar_t* name);
// Deletes an empty subkey. If the subkey has subkeys or values then this
// will fail.
LONG DeleteEmptyKey(const wchar_t* name);
// Deletes a single value within the key.
LONG DeleteValue(const wchar_t* name);
// Getters:
// Reads a REG_DWORD (uint32_t) into |out_value|. If |name| is null or empty,
// reads the key's default value, if any.
LONG ReadValueDW(const wchar_t* name, DWORD* out_value) const;
// Reads a REG_QWORD (int64_t) into |out_value|. If |name| is null or empty,
// reads the key's default value, if any.
LONG ReadInt64(const wchar_t* name, int64_t* out_value) const;
// Reads a string into |out_value|. If |name| is null or empty, reads
// the key's default value, if any.
LONG ReadValue(const wchar_t* name, std::wstring* out_value) const;
// Reads a REG_MULTI_SZ registry field into a vector of strings. Clears
// |values| initially and adds further strings to the list. Returns
// ERROR_CANTREAD if type is not REG_MULTI_SZ.
LONG ReadValues(const wchar_t* name, std::vector<std::wstring>* values);
// Reads raw data into |data|. If |name| is null or empty, reads the key's
// default value, if any.
LONG ReadValue(const wchar_t* name,
void* data,
DWORD* dsize,
DWORD* dtype) const;
// Setters:
// Sets an int32_t value.
LONG WriteValue(const wchar_t* name, DWORD in_value);
// Sets a string value.
LONG WriteValue(const wchar_t* name, const wchar_t* in_value);
// Sets raw data, including type.
LONG WriteValue(const wchar_t* name,
const void* data,
DWORD dsize,
DWORD dtype);
// Starts watching the key to see if any of its values have changed.
// The key must have been opened with the KEY_NOTIFY access privilege.
// Returns true on success.
// To stop watching, delete this RegKey object. To continue watching the
// object after the callback is invoked, call StartWatching again.
bool StartWatching(const ChangeCallback& callback);
HKEY Handle() const { return key_; }
private:
class Watcher;
// Calls RegDeleteKeyEx on supported platforms, alternatively falls back to
// RegDeleteKey.
static LONG RegDeleteKeyExWrapper(HKEY hKey,
const wchar_t* lpSubKey,
REGSAM samDesired,
DWORD Reserved);
// Recursively deletes a key and all of its subkeys.
static LONG RegDelRecurse(HKEY root_key,
const std::wstring& name,
REGSAM access);
HKEY key_; // The registry key being iterated.
REGSAM wow64access_;
std::unique_ptr<Watcher> key_watcher_;
DISALLOW_COPY_AND_ASSIGN(RegKey);
};
// Iterates the entries found in a particular folder on the registry.
class BASE_EXPORT RegistryValueIterator {
public:
// Constructs a Registry Value Iterator with default WOW64 access.
RegistryValueIterator(HKEY root_key, const wchar_t* folder_key);
// Constructs a Registry Key Iterator with specific WOW64 access, one of
// KEY_WOW64_32KEY or KEY_WOW64_64KEY, or 0.
// Note: |wow64access| should be the same access used to open |root_key|
// previously, or a predefined key (e.g. HKEY_LOCAL_MACHINE).
// See http://msdn.microsoft.com/en-us/library/windows/desktop/aa384129.aspx.
RegistryValueIterator(HKEY root_key,
const wchar_t* folder_key,
REGSAM wow64access);
~RegistryValueIterator();
DWORD ValueCount() const;
// True while the iterator is valid.
bool Valid() const;
// Advances to the next registry entry.
void operator++();
const wchar_t* Name() const { return name_.c_str(); }
const wchar_t* Value() const { return value_.data(); }
// ValueSize() is in bytes.
DWORD ValueSize() const { return value_size_; }
DWORD Type() const { return type_; }
int Index() const { return index_; }
private:
// Reads in the current values.
bool Read();
void Initialize(HKEY root_key, const wchar_t* folder_key, REGSAM wow64access);
// The registry key being iterated.
HKEY key_;
// Current index of the iteration.
int index_;
// Current values.
std::wstring name_;
std::vector<wchar_t> value_;
DWORD value_size_;
DWORD type_;
DISALLOW_COPY_AND_ASSIGN(RegistryValueIterator);
};
class BASE_EXPORT RegistryKeyIterator {
public:
// Constructs a Registry Key Iterator with default WOW64 access.
RegistryKeyIterator(HKEY root_key, const wchar_t* folder_key);
// Constructs a Registry Value Iterator with specific WOW64 access, one of
// KEY_WOW64_32KEY or KEY_WOW64_64KEY, or 0.
// Note: |wow64access| should be the same access used to open |root_key|
// previously, or a predefined key (e.g. HKEY_LOCAL_MACHINE).
// See http://msdn.microsoft.com/en-us/library/windows/desktop/aa384129.aspx.
RegistryKeyIterator(HKEY root_key,
const wchar_t* folder_key,
REGSAM wow64access);
~RegistryKeyIterator();
DWORD SubkeyCount() const;
// True while the iterator is valid.
bool Valid() const;
// Advances to the next entry in the folder.
void operator++();
const wchar_t* Name() const { return name_; }
int Index() const { return index_; }
private:
// Reads in the current values.
bool Read();
void Initialize(HKEY root_key, const wchar_t* folder_key, REGSAM wow64access);
// The registry key being iterated.
HKEY key_;
// Current index of the iteration.
int index_;
wchar_t name_[MAX_PATH];
DISALLOW_COPY_AND_ASSIGN(RegistryKeyIterator);
};
} // namespace win
} // namespace base
#endif // BASE_WIN_REGISTRY_H_