1 files changed, 116 insertions, 0 deletions
diff --git a/toolkit/components/antitracking/SettingsChangeObserver.cpp b/toolkit/components/antitracking/SettingsChangeObserver.cpp
new file mode 100644
index 0000000000..eb2ba5bbd3
--- /dev/null
+++ b/toolkit/components/antitracking/SettingsChangeObserver.cpp
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "SettingsChangeObserver.h"
+#include "ContentBlockingUserInteraction.h"
+
+#include "mozilla/Services.h"
+#include "mozilla/Preferences.h"
+#include "nsIObserverService.h"
+#include "nsIPermission.h"
+#include "nsTArray.h"
+
+using namespace mozilla;
+
+namespace {
+
+UniquePtr<nsTArray<SettingsChangeObserver::AntiTrackingSettingsChangedCallback>>
+    gSettingsChangedCallbacks;
+
+}
+
+NS_IMPL_ISUPPORTS(SettingsChangeObserver, nsIObserver)
+
+NS_IMETHODIMP SettingsChangeObserver::Observe(nsISupports* aSubject,
+                                              const char* aTopic,
+                                              const char16_t* aData) {
+  if (!strcmp(aTopic, "xpcom-shutdown")) {
+    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+    if (obs) {
+      obs->RemoveObserver(this, "perm-added");
+      obs->RemoveObserver(this, "perm-changed");
+      obs->RemoveObserver(this, "perm-cleared");
+      obs->RemoveObserver(this, "perm-deleted");
+      obs->RemoveObserver(this, "xpcom-shutdown");
+
+      Preferences::UnregisterPrefixCallback(
+          SettingsChangeObserver::PrivacyPrefChanged,
+          "browser.contentblocking.");
+      Preferences::UnregisterPrefixCallback(
+          SettingsChangeObserver::PrivacyPrefChanged, "network.cookie.");
+      Preferences::UnregisterPrefixCallback(
+          SettingsChangeObserver::PrivacyPrefChanged, "privacy.");
+
+      gSettingsChangedCallbacks = nullptr;
+    }
+  } else {
+    nsCOMPtr<nsIPermission> perm = do_QueryInterface(aSubject);
+    if (perm) {
+      nsAutoCString type;
+      nsresult rv = perm->GetType(type);
+      if (NS_WARN_IF(NS_FAILED(rv)) || type.Equals(USER_INTERACTION_PERM)) {
+        // Ignore failures or notifications that have been sent because of
+        // user interactions.
+        return NS_OK;
+      }
+    }
+
+    RunAntiTrackingSettingsChangedCallbacks();
+  }
+
+  return NS_OK;
+}
+
+// static
+void SettingsChangeObserver::PrivacyPrefChanged(const char* aPref,
+                                                void* aClosure) {
+  RunAntiTrackingSettingsChangedCallbacks();
+}
+
+// static
+void SettingsChangeObserver::RunAntiTrackingSettingsChangedCallbacks() {
+  if (gSettingsChangedCallbacks) {
+    for (auto& callback : *gSettingsChangedCallbacks) {
+      callback();
+    }
+  }
+}
+
+// static
+void SettingsChangeObserver::OnAntiTrackingSettingsChanged(
+    const SettingsChangeObserver::AntiTrackingSettingsChangedCallback&
+        aCallback) {
+  static bool initialized = false;
+  if (!initialized) {
+    // It is possible that while we have some data in our cache, something
+    // changes in our environment that causes the anti-tracking checks below to
+    // change their response.  Therefore, we need to clear our cache when we
+    // detect a related change.
+    Preferences::RegisterPrefixCallback(
+        SettingsChangeObserver::PrivacyPrefChanged, "browser.contentblocking.");
+    Preferences::RegisterPrefixCallback(
+        SettingsChangeObserver::PrivacyPrefChanged, "network.cookie.");
+    Preferences::RegisterPrefixCallback(
+        SettingsChangeObserver::PrivacyPrefChanged, "privacy.");
+
+    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+    if (obs) {
+      RefPtr<SettingsChangeObserver> observer = new SettingsChangeObserver();
+      obs->AddObserver(observer, "perm-added", false);
+      obs->AddObserver(observer, "perm-changed", false);
+      obs->AddObserver(observer, "perm-cleared", false);
+      obs->AddObserver(observer, "perm-deleted", false);
+      obs->AddObserver(observer, "xpcom-shutdown", false);
+    }
+
+    gSettingsChangedCallbacks =
+        MakeUnique<nsTArray<AntiTrackingSettingsChangedCallback>>();
+
+    initialized = true;
+  }
+
+  gSettingsChangedCallbacks->AppendElement(aCallback);
+}