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
   8 #include "mozilla/Preferences.h"
   9 #include "mozilla/dom/MessageChannelBinding.h"
  10 #include "mozilla/dom/MessagePort.h"
  11 #include "nsContentUtils.h"
  12 #include "nsPIDOMWindow.h"
  13
  14 namespace mozilla {
  15 namespace dom {
  16
  17 NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(MessageChannel, mWindow, mPort1, mPort2)
  18 NS_IMPL_CYCLE_COLLECTING_ADDREF(MessageChannel)
  19 NS_IMPL_CYCLE_COLLECTING_RELEASE(MessageChannel)
  20
  21 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(MessageChannel)
  22   NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
  23   NS_INTERFACE_MAP_ENTRY(nsISupports)
  24 NS_INTERFACE_MAP_END
  25
  26 namespace {
  27   bool gPrefInitialized = false;
  28   bool gPrefEnabled = false;
  29
  30 }
  31
  32 /* static */ bool
  33 MessageChannel::Enabled(JSContext* aCx, JSObject* aObj)
  34 {
  35   if (!gPrefInitialized) {
  36     Preferences::AddBoolVarCache(&gPrefEnabled, "dom.messageChannel.enabled");
  37     gPrefInitialized = true;
  38   }
  39
  40   // Enabled by pref
  41   if (gPrefEnabled) {
  42     return true;
  43   }
  44
  45   // Chrome callers are allowed.
  46   if (nsContentUtils::ThreadsafeIsCallerChrome()) {
  47     return true;
  48   }
  49
  50   nsCOMPtr<nsIPrincipal> principal = nsContentUtils::SubjectPrincipal();
  51   MOZ_ASSERT(principal);
  52
  53   nsCOMPtr<nsIURI> uri;
  54   if (NS_FAILED(principal->GetURI(getter_AddRefs(uri))) || !uri) {
  55     return false;
  56   }
  57
  58   bool isResource = false;
  59   if (NS_FAILED(uri->SchemeIs("resource", &isResource))) {
  60     return false;
  61   }
  62
  63   return isResource;
  64 }
  65
  66 MessageChannel::MessageChannel(nsPIDOMWindow* aWindow)
  67   : mWindow(aWindow)
  68 {
  69   MOZ_COUNT_CTOR(MessageChannel);
  70   SetIsDOMBinding();
  71
  72   mPort1 = new MessagePort(mWindow);
  73   mPort2 = new MessagePort(mWindow);
  74
  75   mPort1->Entangle(mPort2);
  76   mPort2->Entangle(mPort1);
  77 }
  78
  79 MessageChannel::~MessageChannel()
  80 {
  81   MOZ_COUNT_DTOR(MessageChannel);
  82 }
  83
  84 JSObject*
  85 MessageChannel::WrapObject(JSContext* aCx)
  86 {
  87   return MessageChannelBinding::Wrap(aCx, this);
  88 }
  89
  90 /* static */ already_AddRefed<MessageChannel>
  91 MessageChannel::Constructor(const GlobalObject& aGlobal, ErrorResult& aRv)
  92 {
  93   nsCOMPtr<nsPIDOMWindow> window = do_QueryInterface(aGlobal.GetAsSupports());
  94   if (!window) {
  95     aRv.Throw(NS_ERROR_UNEXPECTED);
  96     return nullptr;
  97   }
  98
  99   nsRefPtr<MessageChannel> channel = new MessageChannel(window);
 100   return channel.forget();
 101 }
 102
 103 } // namespace dom
 104 } // namespace mozilla