1 files changed, 115 insertions, 0 deletions
diff --git a/dom/permission/PermissionObserver.cpp b/dom/permission/PermissionObserver.cpp
new file mode 100644
index 0000000000..47e1a23918
--- /dev/null
+++ b/dom/permission/PermissionObserver.cpp
@@ -0,0 +1,115 @@
+/* -*- 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/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;
+    }
+
+    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);
+}
+
+void PermissionObserver::Notify(PermissionName aName,
+                                nsIPrincipal& aPrincipal) {
+  for (auto* sink : mSinks) {
+    if (sink->mName != aName) {
+      continue;
+    }
+
+    nsCOMPtr<nsIPrincipal> sinkPrincipal = sink->GetPrincipal();
+    if (NS_WARN_IF(!sinkPrincipal) || !aPrincipal.Equals(sinkPrincipal)) {
+      continue;
+    }
+
+    sink->PermissionChanged();
+  }
+}
+
+NS_IMETHODIMP
+PermissionObserver::Observe(nsISupports* aSubject, const char* aTopic,
+                            const char16_t* aData) {
+  MOZ_ASSERT(!strcmp(aTopic, "perm-changed"));
+
+  if (mSinks.IsEmpty()) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIPermission> perm = do_QueryInterface(aSubject);
+  if (!perm) {
+    return NS_OK;
+  }
+
+  nsCOMPtr<nsIPrincipal> principal;
+  perm->GetPrincipal(getter_AddRefs(principal));
+  if (!principal) {
+    return NS_OK;
+  }
+
+  nsAutoCString type;
+  perm->GetType(type);
+  Maybe<PermissionName> permission = TypeToPermissionName(type);
+  if (permission) {
+    Notify(permission.value(), *principal);
+  }
+
+  return NS_OK;
+}
+
+}  // namespace mozilla::dom