chrome/browser/media/media_device_id_salt.cc

   1 // Copyright 2013 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 #include "chrome/browser/media/media_device_id_salt.h"
   5
   6 #include "base/base64.h"
   7 #include "base/prefs/pref_service.h"
   8 #include "base/rand_util.h"
   9 #include "chrome/browser/profiles/profile_io_data.h"
  10 #include "chrome/common/pref_names.h"
  11 #include "content/public/browser/browser_thread.h"
  12
  13 using content::BrowserThread;
  14
  15 namespace {
  16
  17 std::string CreateSalt() {
  18   std::string salt;
  19   base::Base64Encode(base::RandBytesAsString(16), &salt);
  20   DCHECK(!salt.empty());
  21   return salt;
  22 }
  23
  24 }  // namespace
  25
  26 MediaDeviceIDSalt::MediaDeviceIDSalt(PrefService* pref_service,
  27                                      bool incognito) {
  28   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  29
  30   if (incognito) {
  31     incognito_salt_ = CreateSalt();
  32     return;
  33   }
  34
  35   media_device_id_salt_.Init(prefs::kMediaDeviceIdSalt, pref_service);
  36   if (media_device_id_salt_.GetValue().empty())
  37     media_device_id_salt_.SetValue(CreateSalt());
  38
  39   media_device_id_salt_.MoveToThread(
  40       BrowserThread::GetMessageLoopProxyForThread(BrowserThread::IO));
  41 }
  42
  43 MediaDeviceIDSalt::~MediaDeviceIDSalt() {
  44 }
  45
  46 void MediaDeviceIDSalt::ShutdownOnUIThread() {
  47   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  48   if (incognito_salt_.empty())
  49     media_device_id_salt_.Destroy();
  50 }
  51
  52 std::string MediaDeviceIDSalt::GetSalt() const {
  53   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
  54   if (incognito_salt_.size())
  55     return incognito_salt_;
  56   return media_device_id_salt_.GetValue();
  57 }
  58
  59 void MediaDeviceIDSalt::RegisterProfilePrefs(
  60     user_prefs::PrefRegistrySyncable* registry) {
  61   registry->RegisterStringPref(
  62       prefs::kMediaDeviceIdSalt,
  63       std::string(),
  64       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
  65 }
  66
  67 void MediaDeviceIDSalt::Reset(PrefService* pref_service) {
  68   pref_service->SetString(prefs::kMediaDeviceIdSalt,
  69                           CreateSalt());
  70 }