toolkit/components/antitracking/SettingsChangeObserver.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   5  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "SettingsChangeObserver.h"
   8 #include "ContentBlockingUserInteraction.h"
   9
  10 #include "mozilla/Services.h"
  11 #include "mozilla/Preferences.h"
  12 #include "nsIObserverService.h"
  13 #include "nsIPermission.h"
  14 #include "nsTArray.h"
  15
  16 using namespace mozilla;
  17
  18 namespace {
  19
  20 MOZ_RUNINIT UniquePtr<
  21     nsTArray<SettingsChangeObserver::AntiTrackingSettingsChangedCallback>>
  22     gSettingsChangedCallbacks;
  23
  24 }
  25
  26 NS_IMPL_ISUPPORTS(SettingsChangeObserver, nsIObserver)
  27
  28 NS_IMETHODIMP SettingsChangeObserver::Observe(nsISupports* aSubject,
  29                                               const char* aTopic,
  30                                               const char16_t* aData) {
  31   if (!strcmp(aTopic, "xpcom-shutdown")) {
  32     nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
  33     if (obs) {
  34       obs->RemoveObserver(this, "perm-added");
  35       obs->RemoveObserver(this, "perm-changed");
  36       obs->RemoveObserver(this, "perm-cleared");
  37       obs->RemoveObserver(this, "perm-deleted");
  38       obs->RemoveObserver(this, "xpcom-shutdown");
  39
  40       Preferences::UnregisterPrefixCallback(
  41           SettingsChangeObserver::PrivacyPrefChanged,
  42           "browser.contentblocking.");
  43       Preferences::UnregisterPrefixCallback(
  44           SettingsChangeObserver::PrivacyPrefChanged, "network.cookie.");
  45       Preferences::UnregisterPrefixCallback(
  46           SettingsChangeObserver::PrivacyPrefChanged, "privacy.");
  47
  48       gSettingsChangedCallbacks = nullptr;
  49     }
  50   } else {
  51     nsCOMPtr<nsIPermission> perm = do_QueryInterface(aSubject);
  52     if (perm) {
  53       nsAutoCString type;
  54       nsresult rv = perm->GetType(type);
  55       if (NS_WARN_IF(NS_FAILED(rv)) || type.Equals(USER_INTERACTION_PERM)) {
  56         // Ignore failures or notifications that have been sent because of
  57         // user interactions.
  58         return NS_OK;
  59       }
  60     }
  61
  62     RunAntiTrackingSettingsChangedCallbacks();
  63   }
  64
  65   return NS_OK;
  66 }
  67
  68 // static
  69 void SettingsChangeObserver::PrivacyPrefChanged(const char* aPref,
  70                                                 void* aClosure) {
  71   RunAntiTrackingSettingsChangedCallbacks();
  72 }
  73
  74 // static
  75 void SettingsChangeObserver::RunAntiTrackingSettingsChangedCallbacks() {
  76   if (gSettingsChangedCallbacks) {
  77     for (auto& callback : *gSettingsChangedCallbacks) {
  78       callback();
  79     }
  80   }
  81 }
  82
  83 // static
  84 void SettingsChangeObserver::OnAntiTrackingSettingsChanged(
  85     const SettingsChangeObserver::AntiTrackingSettingsChangedCallback&
  86         aCallback) {
  87   static bool initialized = false;
  88   if (!initialized) {
  89     // It is possible that while we have some data in our cache, something
  90     // changes in our environment that causes the anti-tracking checks below to
  91     // change their response.  Therefore, we need to clear our cache when we
  92     // detect a related change.
  93     Preferences::RegisterPrefixCallback(
  94         SettingsChangeObserver::PrivacyPrefChanged, "browser.contentblocking.");
  95     Preferences::RegisterPrefixCallback(
  96         SettingsChangeObserver::PrivacyPrefChanged, "network.cookie.");
  97     Preferences::RegisterPrefixCallback(
  98         SettingsChangeObserver::PrivacyPrefChanged, "privacy.");
  99
 100     nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
 101     if (obs) {
 102       RefPtr<SettingsChangeObserver> observer = new SettingsChangeObserver();
 103       obs->AddObserver(observer, "perm-added", false);
 104       obs->AddObserver(observer, "perm-changed", false);
 105       obs->AddObserver(observer, "perm-cleared", false);
 106       obs->AddObserver(observer, "perm-deleted", false);
 107       obs->AddObserver(observer, "xpcom-shutdown", false);
 108     }
 109
 110     gSettingsChangedCallbacks =
 111         MakeUnique<nsTArray<AntiTrackingSettingsChangedCallback>>();
 112
 113     initialized = true;
 114   }
 115
 116   gSettingsChangedCallbacks->AppendElement(aCallback);
 117 }