dom/base/MessageChannel.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "MessageChannel.h"
   7 #include "mozilla/Preferences.h"
   8 #include "mozilla/dom/MessageChannelBinding.h"
   9 #include "mozilla/dom/MessagePort.h"
  10 #include "nsContentUtils.h"
  11 #include "nsPIDOMWindow.h"
  12
  13 namespace mozilla {
  14 namespace dom {
  15
  16 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE_3(MessageChannel, mWindow, mPort1, mPort2)
  17 NS_IMPL_CYCLE_COLLECTING_ADDREF(MessageChannel)
  18 NS_IMPL_CYCLE_COLLECTING_RELEASE(MessageChannel)
  19
  20 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MessageChannel)
  21   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  22   NS_INTERFACE_MAP_ENTRY(nsISupports)
  23 NS_INTERFACE_MAP_END
  24
  25 namespace {
  26   bool gPrefInitialized = false;
  27   bool gPrefEnabled = false;
  28
  29 }
  30
  31
  32 /* static */ bool
  33 MessageChannel::PrefEnabled()
  34 {
  35   if (!gPrefInitialized) {
  36     Preferences::AddBoolVarCache(&gPrefEnabled, "dom.messageChannel.enabled");
  37     gPrefInitialized = true;
  38   }
  39
  40   return gPrefEnabled;
  41 }
  42
  43 MessageChannel::MessageChannel(nsPIDOMWindow* aWindow)
  44   : mWindow(aWindow)
  45 {
  46   MOZ_COUNT_CTOR(MessageChannel);
  47   SetIsDOMBinding();
  48
  49   mPort1 = new MessagePort(mWindow);
  50   mPort2 = new MessagePort(mWindow);
  51
  52   mPort1->Entangle(mPort2);
  53   mPort2->Entangle(mPort1);
  54 }
  55
  56 MessageChannel::~MessageChannel()
  57 {
  58   MOZ_COUNT_DTOR(MessageChannel);
  59 }
  60
  61 JSObject*
  62 MessageChannel::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aScope)
  63 {
  64   return MessageChannelBinding::Wrap(aCx, aScope, this);
  65 }
  66
  67 /* static */ already_AddRefed<MessageChannel>
  68 MessageChannel::Constructor(const GlobalObject& aGlobal, ErrorResult& aRv)
  69 {
  70   nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.GetAsSupports());
  71   if (!window) {
  72     aRv.Throw(NS_ERROR_UNEXPECTED);
  73     return nullptr;
  74   }
  75
  76   nsRefPtr<MessageChannel> channel = new MessageChannel(window);
  77   return channel.forget();
  78 }
  79
  80 } // namespace dom
  81 } // namespace mozilla