1 files changed, 131 insertions, 0 deletions
diff --git a/dom/permission/PermissionObserver.cpp b/dom/permission/PermissionObserver.cpp
new file mode 100644
index 0000000000..26ffd02abc
--- /dev/null
+++ b/dom/permission/PermissionObserver.cpp
@@ -0,0 +1,131 @@
+/* -*- 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 "PermissionObserver.h"
+
+#include "mozilla/dom/PermissionStatus.h"
+#include "mozilla/dom/WindowGlobalChild.h"
+#include "mozilla/Services.h"
+#include "mozilla/UniquePtr.h"
+#include "nsIObserverService.h"
+#include "nsIPermission.h"
+#include "PermissionUtils.h"
+
+namespace mozilla::dom {
+
+namespace {
+PermissionObserver* gInstance = nullptr;
+}  // namespace
+
+NS_IMPL_ISUPPORTS(PermissionObserver, nsIObserver, nsISupportsWeakReference)
+
+PermissionObserver::PermissionObserver() { MOZ_ASSERT(!gInstance); }
+
+PermissionObserver::~PermissionObserver() {
+  MOZ_ASSERT(mSinks.IsEmpty());
+  MOZ_ASSERT(gInstance == this);
+
+  gInstance = nullptr;
+}
+
+/* static */
+already_AddRefed<PermissionObserver> PermissionObserver::GetInstance() {
+  RefPtr<PermissionObserver> instance = gInstance;
+  if (!instance) {
+    instance = new PermissionObserver();
+
+    nsCOMPtr<nsIObserverService> obs = services::GetObserverService();
+    if (NS_WARN_IF(!obs)) {
+      return nullptr;
+    }
+
+    nsresult rv = obs->AddObserver(instance, "perm-changed", true);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return nullptr;
+    }
+
+    rv = obs->AddObserver(instance, "perm-changed-notify-only", true);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return nullptr;
+    }
+
+    gInstance = instance;
+  }
+
+  return instance.forget();
+}
+
+void PermissionObserver::AddSink(PermissionStatus* aSink) {
+  MOZ_ASSERT(aSink);
+  MOZ_ASSERT(!mSinks.Contains(aSink));
+
+  mSinks.AppendElement(aSink);
+}
+
+void PermissionObserver::RemoveSink(PermissionStatus* aSink) {
+  MOZ_ASSERT(aSink);
+  MOZ_ASSERT(mSinks.Contains(aSink));
+
+  mSinks.RemoveElement(aSink);
+}
+
+NS_IMETHODIMP
+PermissionObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                            const char16_t* aData) {
+  MOZ_ASSERT(!strcmp(aTopic, "perm-changed") ||
+             !strcmp(aTopic, "perm-changed-notify-only"));
+
+  if (mSinks.IsEmpty()) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIPermission> perm = nullptr;
+  nsCOMPtr<nsPIDOMWindowInner> innerWindow = nullptr;
+  nsAutoCString type;
+
+  if (!strcmp(aTopic, "perm-changed")) {
+    perm = do_QueryInterface(aSubject);
+    if (!perm) {
+      return NS_OK;
+    }
+    perm->GetType(type);
+  } else if (!strcmp(aTopic, "perm-changed-notify-only")) {
+    innerWindow = do_QueryInterface(aSubject);
+    if (!innerWindow) {
+      return NS_OK;
+    }
+    type = NS_ConvertUTF16toUTF8(aData);
+  }
+
+  Maybe<PermissionName> permission = TypeToPermissionName(type);
+  if (permission) {
+    for (auto* sink : mSinks) {
+      if (sink->mName != permission.value()) {
+        continue;
+      }
+      // Check for permissions that are changed for this sink's principal
+      // via the "perm-changed" notification. These permissions affect
+      // the window the sink (PermissionStatus) is held in directly.
+      if (perm && sink->MaybeUpdatedBy(perm)) {
+        sink->PermissionChanged();
+      }
+      // Check for permissions that are changed for this sink's principal
+      // via the "perm-changed-notify-only" notification. These permissions
+      // affect the window the sink (PermissionStatus) is held in indirectly- if
+      // the window is same-party with the secondary key of a permission. For
+      // example, a "3rdPartyFrameStorage^https://example.com" permission would
+      // return true on these checks where sink is in a window that is same-site
+      // with https://example.com.
+      if (innerWindow && sink->MaybeUpdatedByNotifyOnly(innerWindow)) {
+        sink->PermissionChanged();
+      }
+    }
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::dom