michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #include "base/win/registry.h"
michael@0: 
michael@0: #include <shlwapi.h>
michael@0: #include <algorithm>
michael@0: 
michael@0: #include "base/logging.h"
michael@0: #include "base/strings/string_util.h"
michael@0: #include "base/threading/thread_restrictions.h"
michael@0: 
michael@0: #pragma comment(lib, "shlwapi.lib")  // for SHDeleteKey
michael@0: 
michael@0: namespace base {
michael@0: namespace win {
michael@0: 
michael@0: namespace {
michael@0: 
michael@0: // RegEnumValue() reports the number of characters from the name that were
michael@0: // written to the buffer, not how many there are. This constant is the maximum
michael@0: // name size, such that a buffer with this size should read any name.
michael@0: const DWORD MAX_REGISTRY_NAME_SIZE = 16384;
michael@0: 
michael@0: // Registry values are read as BYTE* but can have wchar_t* data whose last
michael@0: // wchar_t is truncated. This function converts the reported |byte_size| to
michael@0: // a size in wchar_t that can store a truncated wchar_t if necessary.
michael@0: inline DWORD to_wchar_size(DWORD byte_size) {
michael@0:   return (byte_size + sizeof(wchar_t) - 1) / sizeof(wchar_t);
michael@0: }
michael@0: 
michael@0: }  // namespace
michael@0: 
michael@0: // RegKey ----------------------------------------------------------------------
michael@0: 
michael@0: RegKey::RegKey()
michael@0:     : key_(NULL),
michael@0:       watch_event_(0) {
michael@0: }
michael@0: 
michael@0: RegKey::RegKey(HKEY key)
michael@0:     : key_(key),
michael@0:       watch_event_(0) {
michael@0: }
michael@0: 
michael@0: RegKey::RegKey(HKEY rootkey, const wchar_t* subkey, REGSAM access)
michael@0:     : key_(NULL),
michael@0:       watch_event_(0) {
michael@0:   if (rootkey) {
michael@0:     if (access & (KEY_SET_VALUE | KEY_CREATE_SUB_KEY | KEY_CREATE_LINK))
michael@0:       Create(rootkey, subkey, access);
michael@0:     else
michael@0:       Open(rootkey, subkey, access);
michael@0:   } else {
michael@0:     DCHECK(!subkey);
michael@0:   }
michael@0: }
michael@0: 
michael@0: RegKey::~RegKey() {
michael@0:   Close();
michael@0: }
michael@0: 
michael@0: LONG RegKey::Create(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
michael@0:   DWORD disposition_value;
michael@0:   return CreateWithDisposition(rootkey, subkey, &disposition_value, access);
michael@0: }
michael@0: 
michael@0: LONG RegKey::CreateWithDisposition(HKEY rootkey, const wchar_t* subkey,
michael@0:                                    DWORD* disposition, REGSAM access) {
michael@0:   DCHECK(rootkey && subkey && access && disposition);
michael@0:   Close();
michael@0: 
michael@0:   LONG result = RegCreateKeyEx(rootkey, subkey, 0, NULL,
michael@0:                                REG_OPTION_NON_VOLATILE, access, NULL, &key_,
michael@0:                                disposition);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::CreateKey(const wchar_t* name, REGSAM access) {
michael@0:   DCHECK(name && access);
michael@0:   HKEY subkey = NULL;
michael@0:   LONG result = RegCreateKeyEx(key_, name, 0, NULL, REG_OPTION_NON_VOLATILE,
michael@0:                                access, NULL, &subkey, NULL);
michael@0:   Close();
michael@0: 
michael@0:   key_ = subkey;
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::Open(HKEY rootkey, const wchar_t* subkey, REGSAM access) {
michael@0:   DCHECK(rootkey && subkey && access);
michael@0:   Close();
michael@0: 
michael@0:   LONG result = RegOpenKeyEx(rootkey, subkey, 0, access, &key_);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::OpenKey(const wchar_t* relative_key_name, REGSAM access) {
michael@0:   DCHECK(relative_key_name && access);
michael@0:   HKEY subkey = NULL;
michael@0:   LONG result = RegOpenKeyEx(key_, relative_key_name, 0, access, &subkey);
michael@0: 
michael@0:   // We have to close the current opened key before replacing it with the new
michael@0:   // one.
michael@0:   Close();
michael@0: 
michael@0:   key_ = subkey;
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: void RegKey::Close() {
michael@0:   StopWatching();
michael@0:   if (key_) {
michael@0:     ::RegCloseKey(key_);
michael@0:     key_ = NULL;
michael@0:   }
michael@0: }
michael@0: 
michael@0: void RegKey::Set(HKEY key) {
michael@0:   if (key_ != key) {
michael@0:     Close();
michael@0:     key_ = key;
michael@0:   }
michael@0: }
michael@0: 
michael@0: HKEY RegKey::Take() {
michael@0:   StopWatching();
michael@0:   HKEY key = key_;
michael@0:   key_ = NULL;
michael@0:   return key;
michael@0: }
michael@0: 
michael@0: bool RegKey::HasValue(const wchar_t* name) const {
michael@0:   return RegQueryValueEx(key_, name, 0, NULL, NULL, NULL) == ERROR_SUCCESS;
michael@0: }
michael@0: 
michael@0: DWORD RegKey::GetValueCount() const {
michael@0:   DWORD count = 0;
michael@0:   LONG result = RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
michael@0:                                 NULL, NULL, NULL, NULL);
michael@0:   return (result == ERROR_SUCCESS) ? count : 0;
michael@0: }
michael@0: 
michael@0: LONG RegKey::GetValueNameAt(int index, std::wstring* name) const {
michael@0:   wchar_t buf[256];
michael@0:   DWORD bufsize = arraysize(buf);
michael@0:   LONG r = ::RegEnumValue(key_, index, buf, &bufsize, NULL, NULL, NULL, NULL);
michael@0:   if (r == ERROR_SUCCESS)
michael@0:     *name = buf;
michael@0: 
michael@0:   return r;
michael@0: }
michael@0: 
michael@0: LONG RegKey::DeleteKey(const wchar_t* name) {
michael@0:   DCHECK(key_);
michael@0:   DCHECK(name);
michael@0:   LONG result = SHDeleteKey(key_, name);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::DeleteValue(const wchar_t* value_name) {
michael@0:   DCHECK(key_);
michael@0:   LONG result = RegDeleteValue(key_, value_name);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::ReadValueDW(const wchar_t* name, DWORD* out_value) const {
michael@0:   DCHECK(out_value);
michael@0:   DWORD type = REG_DWORD;
michael@0:   DWORD size = sizeof(DWORD);
michael@0:   DWORD local_value = 0;
michael@0:   LONG result = ReadValue(name, &local_value, &size, &type);
michael@0:   if (result == ERROR_SUCCESS) {
michael@0:     if ((type == REG_DWORD || type == REG_BINARY) && size == sizeof(DWORD))
michael@0:       *out_value = local_value;
michael@0:     else
michael@0:       result = ERROR_CANTREAD;
michael@0:   }
michael@0: 
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::ReadInt64(const wchar_t* name, int64* out_value) const {
michael@0:   DCHECK(out_value);
michael@0:   DWORD type = REG_QWORD;
michael@0:   int64 local_value = 0;
michael@0:   DWORD size = sizeof(local_value);
michael@0:   LONG result = ReadValue(name, &local_value, &size, &type);
michael@0:   if (result == ERROR_SUCCESS) {
michael@0:     if ((type == REG_QWORD || type == REG_BINARY) &&
michael@0:         size == sizeof(local_value))
michael@0:       *out_value = local_value;
michael@0:     else
michael@0:       result = ERROR_CANTREAD;
michael@0:   }
michael@0: 
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::ReadValue(const wchar_t* name, std::wstring* out_value) const {
michael@0:   DCHECK(out_value);
michael@0:   const size_t kMaxStringLength = 1024;  // This is after expansion.
michael@0:   // Use the one of the other forms of ReadValue if 1024 is too small for you.
michael@0:   wchar_t raw_value[kMaxStringLength];
michael@0:   DWORD type = REG_SZ, size = sizeof(raw_value);
michael@0:   LONG result = ReadValue(name, raw_value, &size, &type);
michael@0:   if (result == ERROR_SUCCESS) {
michael@0:     if (type == REG_SZ) {
michael@0:       *out_value = raw_value;
michael@0:     } else if (type == REG_EXPAND_SZ) {
michael@0:       wchar_t expanded[kMaxStringLength];
michael@0:       size = ExpandEnvironmentStrings(raw_value, expanded, kMaxStringLength);
michael@0:       // Success: returns the number of wchar_t's copied
michael@0:       // Fail: buffer too small, returns the size required
michael@0:       // Fail: other, returns 0
michael@0:       if (size == 0 || size > kMaxStringLength) {
michael@0:         result = ERROR_MORE_DATA;
michael@0:       } else {
michael@0:         *out_value = expanded;
michael@0:       }
michael@0:     } else {
michael@0:       // Not a string. Oops.
michael@0:       result = ERROR_CANTREAD;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::ReadValue(const wchar_t* name,
michael@0:                        void* data,
michael@0:                        DWORD* dsize,
michael@0:                        DWORD* dtype) const {
michael@0:   LONG result = RegQueryValueEx(key_, name, 0, dtype,
michael@0:                                 reinterpret_cast<LPBYTE>(data), dsize);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::ReadValues(const wchar_t* name,
michael@0:                         std::vector<std::wstring>* values) {
michael@0:   values->clear();
michael@0: 
michael@0:   DWORD type = REG_MULTI_SZ;
michael@0:   DWORD size = 0;
michael@0:   LONG result = ReadValue(name, NULL, &size, &type);
michael@0:   if (FAILED(result) || size == 0)
michael@0:     return result;
michael@0: 
michael@0:   if (type != REG_MULTI_SZ)
michael@0:     return ERROR_CANTREAD;
michael@0: 
michael@0:   std::vector<wchar_t> buffer(size / sizeof(wchar_t));
michael@0:   result = ReadValue(name, &buffer[0], &size, NULL);
michael@0:   if (FAILED(result) || size == 0)
michael@0:     return result;
michael@0: 
michael@0:   // Parse the double-null-terminated list of strings.
michael@0:   // Note: This code is paranoid to not read outside of |buf|, in the case where
michael@0:   // it may not be properly terminated.
michael@0:   const wchar_t* entry = &buffer[0];
michael@0:   const wchar_t* buffer_end = entry + (size / sizeof(wchar_t));
michael@0:   while (entry < buffer_end && entry[0] != '\0') {
michael@0:     const wchar_t* entry_end = std::find(entry, buffer_end, L'\0');
michael@0:     values->push_back(std::wstring(entry, entry_end));
michael@0:     entry = entry_end + 1;
michael@0:   }
michael@0:   return 0;
michael@0: }
michael@0: 
michael@0: LONG RegKey::WriteValue(const wchar_t* name, DWORD in_value) {
michael@0:   return WriteValue(
michael@0:       name, &in_value, static_cast<DWORD>(sizeof(in_value)), REG_DWORD);
michael@0: }
michael@0: 
michael@0: LONG RegKey::WriteValue(const wchar_t * name, const wchar_t* in_value) {
michael@0:   return WriteValue(name, in_value,
michael@0:       static_cast<DWORD>(sizeof(*in_value) * (wcslen(in_value) + 1)), REG_SZ);
michael@0: }
michael@0: 
michael@0: LONG RegKey::WriteValue(const wchar_t* name,
michael@0:                         const void* data,
michael@0:                         DWORD dsize,
michael@0:                         DWORD dtype) {
michael@0:   DCHECK(data || !dsize);
michael@0: 
michael@0:   LONG result = RegSetValueEx(key_, name, 0, dtype,
michael@0:       reinterpret_cast<LPBYTE>(const_cast<void*>(data)), dsize);
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: LONG RegKey::StartWatching() {
michael@0:   DCHECK(key_);
michael@0:   if (!watch_event_)
michael@0:     watch_event_ = CreateEvent(NULL, TRUE, FALSE, NULL);
michael@0: 
michael@0:   DWORD filter = REG_NOTIFY_CHANGE_NAME |
michael@0:                  REG_NOTIFY_CHANGE_ATTRIBUTES |
michael@0:                  REG_NOTIFY_CHANGE_LAST_SET |
michael@0:                  REG_NOTIFY_CHANGE_SECURITY;
michael@0: 
michael@0:   // Watch the registry key for a change of value.
michael@0:   LONG result = RegNotifyChangeKeyValue(key_, TRUE, filter, watch_event_, TRUE);
michael@0:   if (result != ERROR_SUCCESS) {
michael@0:     CloseHandle(watch_event_);
michael@0:     watch_event_ = 0;
michael@0:   }
michael@0: 
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: bool RegKey::HasChanged() {
michael@0:   if (watch_event_) {
michael@0:     if (WaitForSingleObject(watch_event_, 0) == WAIT_OBJECT_0) {
michael@0:       StartWatching();
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: LONG RegKey::StopWatching() {
michael@0:   LONG result = ERROR_INVALID_HANDLE;
michael@0:   if (watch_event_) {
michael@0:     CloseHandle(watch_event_);
michael@0:     watch_event_ = 0;
michael@0:     result = ERROR_SUCCESS;
michael@0:   }
michael@0:   return result;
michael@0: }
michael@0: 
michael@0: // RegistryValueIterator ------------------------------------------------------
michael@0: 
michael@0: RegistryValueIterator::RegistryValueIterator(HKEY root_key,
michael@0:                                              const wchar_t* folder_key)
michael@0:     : name_(MAX_PATH, L'\0'),
michael@0:       value_(MAX_PATH, L'\0') {
michael@0:   LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
michael@0:   if (result != ERROR_SUCCESS) {
michael@0:     key_ = NULL;
michael@0:   } else {
michael@0:     DWORD count = 0;
michael@0:     result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL, &count,
michael@0:                                NULL, NULL, NULL, NULL);
michael@0: 
michael@0:     if (result != ERROR_SUCCESS) {
michael@0:       ::RegCloseKey(key_);
michael@0:       key_ = NULL;
michael@0:     } else {
michael@0:       index_ = count - 1;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   Read();
michael@0: }
michael@0: 
michael@0: RegistryValueIterator::~RegistryValueIterator() {
michael@0:   if (key_)
michael@0:     ::RegCloseKey(key_);
michael@0: }
michael@0: 
michael@0: DWORD RegistryValueIterator::ValueCount() const {
michael@0:   DWORD count = 0;
michael@0:   LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, NULL, NULL, NULL,
michael@0:                                   &count, NULL, NULL, NULL, NULL);
michael@0:   if (result != ERROR_SUCCESS)
michael@0:     return 0;
michael@0: 
michael@0:   return count;
michael@0: }
michael@0: 
michael@0: bool RegistryValueIterator::Valid() const {
michael@0:   return key_ != NULL && index_ >= 0;
michael@0: }
michael@0: 
michael@0: void RegistryValueIterator::operator++() {
michael@0:   --index_;
michael@0:   Read();
michael@0: }
michael@0: 
michael@0: bool RegistryValueIterator::Read() {
michael@0:   if (Valid()) {
michael@0:     DWORD capacity = static_cast<DWORD>(name_.capacity());
michael@0:     DWORD name_size = capacity;
michael@0:     // |value_size_| is in bytes. Reserve the last character for a NUL.
michael@0:     value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
michael@0:     LONG result = ::RegEnumValue(
michael@0:         key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
michael@0:         reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
michael@0: 
michael@0:     if (result == ERROR_MORE_DATA) {
michael@0:       // Registry key names are limited to 255 characters and fit within
michael@0:       // MAX_PATH (which is 260) but registry value names can use up to 16,383
michael@0:       // characters and the value itself is not limited
michael@0:       // (from http://msdn.microsoft.com/en-us/library/windows/desktop/
michael@0:       // ms724872(v=vs.85).aspx).
michael@0:       // Resize the buffers and retry if their size caused the failure.
michael@0:       DWORD value_size_in_wchars = to_wchar_size(value_size_);
michael@0:       if (value_size_in_wchars + 1 > value_.size())
michael@0:         value_.resize(value_size_in_wchars + 1, L'\0');
michael@0:       value_size_ = static_cast<DWORD>((value_.size() - 1) * sizeof(wchar_t));
michael@0:       name_size = name_size == capacity ? MAX_REGISTRY_NAME_SIZE : capacity;
michael@0:       result = ::RegEnumValue(
michael@0:           key_, index_, WriteInto(&name_, name_size), &name_size, NULL, &type_,
michael@0:           reinterpret_cast<BYTE*>(vector_as_array(&value_)), &value_size_);
michael@0:     }
michael@0: 
michael@0:     if (result == ERROR_SUCCESS) {
michael@0:       DCHECK_LT(to_wchar_size(value_size_), value_.size());
michael@0:       value_[to_wchar_size(value_size_)] = L'\0';
michael@0:       return true;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   name_[0] = L'\0';
michael@0:   value_[0] = L'\0';
michael@0:   value_size_ = 0;
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: // RegistryKeyIterator --------------------------------------------------------
michael@0: 
michael@0: RegistryKeyIterator::RegistryKeyIterator(HKEY root_key,
michael@0:                                          const wchar_t* folder_key) {
michael@0:   LONG result = RegOpenKeyEx(root_key, folder_key, 0, KEY_READ, &key_);
michael@0:   if (result != ERROR_SUCCESS) {
michael@0:     key_ = NULL;
michael@0:   } else {
michael@0:     DWORD count = 0;
michael@0:     LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
michael@0:                                     NULL, NULL, NULL, NULL, NULL);
michael@0: 
michael@0:     if (result != ERROR_SUCCESS) {
michael@0:       ::RegCloseKey(key_);
michael@0:       key_ = NULL;
michael@0:     } else {
michael@0:       index_ = count - 1;
michael@0:     }
michael@0:   }
michael@0: 
michael@0:   Read();
michael@0: }
michael@0: 
michael@0: RegistryKeyIterator::~RegistryKeyIterator() {
michael@0:   if (key_)
michael@0:     ::RegCloseKey(key_);
michael@0: }
michael@0: 
michael@0: DWORD RegistryKeyIterator::SubkeyCount() const {
michael@0:   DWORD count = 0;
michael@0:   LONG result = ::RegQueryInfoKey(key_, NULL, 0, NULL, &count, NULL, NULL,
michael@0:                                   NULL, NULL, NULL, NULL, NULL);
michael@0:   if (result != ERROR_SUCCESS)
michael@0:     return 0;
michael@0: 
michael@0:   return count;
michael@0: }
michael@0: 
michael@0: bool RegistryKeyIterator::Valid() const {
michael@0:   return key_ != NULL && index_ >= 0;
michael@0: }
michael@0: 
michael@0: void RegistryKeyIterator::operator++() {
michael@0:   --index_;
michael@0:   Read();
michael@0: }
michael@0: 
michael@0: bool RegistryKeyIterator::Read() {
michael@0:   if (Valid()) {
michael@0:     DWORD ncount = arraysize(name_);
michael@0:     FILETIME written;
michael@0:     LONG r = ::RegEnumKeyEx(key_, index_, name_, &ncount, NULL, NULL,
michael@0:                             NULL, &written);
michael@0:     if (ERROR_SUCCESS == r)
michael@0:       return true;
michael@0:   }
michael@0: 
michael@0:   name_[0] = '\0';
michael@0:   return false;
michael@0: }
michael@0: 
michael@0: }  // namespace win
michael@0: }  // namespace base