Bug 1105827 - Part 9: Add PermissionObserver to watch for perm-changed notifications. r=baku

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/Services.h"
+#include "mozilla/UniquePtr.h"
+#include "nsIObserverService.h"
+#include "nsIPermission.h"
+#include "PermissionUtils.h"
+
+namespace mozilla {
+namespace 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()
+{
+  nsRefPtr<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;
+    }
+
+    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.get());
+  if (permission) {
+    Notify(permission.value(), *principal);
+  }
+
+  return NS_OK;
+}
+
+} // namespace dom
+} // namespace mozilla

dom/permission/PermissionObserver.h

@@ -0,0 +1,49 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_PermissionObserver_h_
+#define mozilla_dom_PermissionObserver_h_
+
+#include "mozilla/dom/PermissionsBinding.h"
+
+#include "nsIObserver.h"
+#include "nsIPrincipal.h"
+#include "nsTArray.h"
+#include "nsWeakReference.h"
+
+namespace mozilla {
+namespace dom {
+
+class PermissionStatus;
+
+// Singleton that watches for perm-changed notifications in order to notify
+// PermissionStatus objects.
+class PermissionObserver final
+  : public nsIObserver
+  , public nsSupportsWeakReference
+{
+public:
+  NS_DECL_ISUPPORTS
+  NS_DECL_NSIOBSERVER
+
+  static already_AddRefed<PermissionObserver> GetInstance();
+
+  void AddSink(PermissionStatus* aObs);
+  void RemoveSink(PermissionStatus* aObs);
+
+private:
+  PermissionObserver();
+  virtual ~PermissionObserver();
+
+  void Notify(PermissionName aName, nsIPrincipal& aPrincipal);
+
+  nsTArray<PermissionStatus*> mSinks;
+};
+
+} // namespace dom
+} // namespace mozilla
+
+#endif

dom/permission/PermissionStatus.cpp

@@ -9,6 +9,7 @@
 #include "mozilla/Services.h"
 #include "mozilla/UniquePtr.h"
 #include "nsIPermissionManager.h"
+#include "PermissionObserver.h"
 #include "PermissionUtils.h"
 
 namespace mozilla {
@@ -23,7 +24,7 @@ PermissionStatus::Create(nsPIDOMWindow* aWindow,
   *aStatus = nullptr;
 
   UniquePtr<PermissionStatus> status(new PermissionStatus(aWindow, aName));
-  nsresult rv = status->UpdateState();
+  nsresult rv = status->Init();
   if (NS_WARN_IF(NS_FAILED(rv))) {
     return rv;
   }
@@ -40,8 +41,29 @@ PermissionStatus::PermissionStatus(nsPIDOMWindow* aWindow,
 {
 }
 
+nsresult
+PermissionStatus::Init()
+{
+  mObserver = PermissionObserver::GetInstance();
+  if (NS_WARN_IF(!mObserver)) {
+    return NS_ERROR_FAILURE;
+  }
+
+  mObserver->AddSink(this);
+
+  nsresult rv = UpdateState();
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return rv;
+  }
+
+  return NS_OK;
+}
+
 PermissionStatus::~PermissionStatus()
 {
+  if (mObserver) {
+    mObserver->RemoveSink(this);
+  }
 }
 
 JSObject*
@@ -75,5 +97,21 @@ PermissionStatus::UpdateState()
   return NS_OK;
 }
 
+nsIPrincipal*
+PermissionStatus::GetPrincipal() const
+{
+  nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(GetOwner());
+  if (NS_WARN_IF(!window)) {
+    return nullptr;
+  }
+
+  nsIDocument* doc = window->GetExtantDoc();
+  if (NS_WARN_IF(!doc)) {
+    return nullptr;
+  }
+
+  return doc->NodePrincipal();
+}
+
 } // namespace dom
 } // namespace mozilla

dom/permission/PermissionStatus.h

@@ -14,9 +14,13 @@
 namespace mozilla {
 namespace dom {
 
+class PermissionObserver;
+
 class PermissionStatus final
   : public DOMEventTargetHelper
 {
+  friend class PermissionObserver;
+
 public:
   ~PermissionStatus();
 
@@ -34,10 +38,18 @@ public:
 private:
   PermissionStatus(nsPIDOMWindow* aWindow, PermissionName aName);
 
+  nsresult Init();
+
   nsresult UpdateState();
 
+  nsIPrincipal* GetPrincipal() const;
+
+  void PermissionChanged() {}
+
   PermissionName mName;
   PermissionState mState;
+
+  nsRefPtr<PermissionObserver> mObserver;
 };
 
 } // namespace dom

dom/permission/moz.build

@@ -10,6 +10,7 @@ EXPORTS.mozilla.dom += [
 ]
 
 UNIFIED_SOURCES += [
+    'PermissionObserver.cpp',
     'Permissions.cpp',
     'PermissionStatus.cpp',
     'PermissionUtils.cpp',