The Tor Browser: dom/base/MessagePort.cpp@b8a032363ba2 (annotated)

dom/base/MessagePort.cpp@b8a032363ba2 (annotated)

dom/base/MessagePort.cpp

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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 "MessagePort.h"
 #include "MessageEvent.h"
 #include "mozilla/dom/Event.h"
 #include "mozilla/dom/MessageChannel.h"
 #include "mozilla/dom/MessagePortBinding.h"
 #include "mozilla/dom/MessagePortList.h"
 #include "mozilla/dom/StructuredCloneTags.h"
 #include "nsContentUtils.h"
 #include "nsGlobalWindow.h"
 #include "nsPresContext.h"
 #include "nsIDocument.h"
 #include "nsIDOMFile.h"
 #include "nsIDOMFileList.h"
 #include "nsIPresShell.h"
 namespace mozilla {
 namespace dom {
 class DispatchEventRunnable : public nsRunnable
 {
   friend class MessagePort;
   public:
     DispatchEventRunnable(MessagePort* aPort)
       : mPort(aPort)
     {
     }
     NS_IMETHOD
     Run()
     {
       nsRefPtr<DispatchEventRunnable> mKungFuDeathGrip(this);
       mPort->mDispatchRunnable = nullptr;
       mPort->Dispatch();
       return NS_OK;
     }
   private:
     nsRefPtr<MessagePort> mPort;
 };
 class PostMessageRunnable : public nsRunnable
 {
   friend class MessagePort;
   public:
     NS_DECL_NSIRUNNABLE
     PostMessageRunnable()
     {
     }
     ~PostMessageRunnable()
     {
     }
     JSAutoStructuredCloneBuffer& Buffer()
     {
       return mBuffer;
     }
     bool StoreISupports(nsISupports* aSupports)
     {
       mSupportsArray.AppendElement(aSupports);
       return true;
     }
     void Dispatch(MessagePort* aPort)
     {
       mPort = aPort;
       NS_DispatchToCurrentThread(this);
     }
   private:
     nsRefPtr<MessagePort> mPort;
     JSAutoStructuredCloneBuffer mBuffer;
     nsTArray<nsCOMPtr<nsISupports> > mSupportsArray;
 };
 namespace {
 struct StructuredCloneInfo
 {
   PostMessageRunnable* mEvent;
   MessagePort* mPort;
   nsRefPtrHashtable<nsRefPtrHashKey<MessagePortBase>, MessagePortBase> mPorts;
 };
 static JSObject*
 PostMessageReadStructuredClone(JSContext* cx,
                                JSStructuredCloneReader* reader,
                                uint32_t tag,
                                uint32_t data,
                                void* closure)
 {
   if (tag == SCTAG_DOM_BLOB || tag == SCTAG_DOM_FILELIST) {
     NS_ASSERTION(!data, "Data should be empty");
     nsISupports* supports;
     if (JS_ReadBytes(reader, &supports, sizeof(supports))) {
       JS::Rooted<JS::Value> val(cx);
       if (NS_SUCCEEDED(nsContentUtils::WrapNative(cx, supports, &val))) {
         return JSVAL_TO_OBJECT(val);
       }
     }
   }
   const JSStructuredCloneCallbacks* runtimeCallbacks =
     js::GetContextStructuredCloneCallbacks(cx);
   if (runtimeCallbacks) {
     return runtimeCallbacks->read(cx, reader, tag, data, nullptr);
   }
   return nullptr;
 }
 static bool
 PostMessageWriteStructuredClone(JSContext* cx,
                                 JSStructuredCloneWriter* writer,
                                 JS::Handle<JSObject*> obj,
                                 void *closure)
 {
   StructuredCloneInfo* scInfo = static_cast<StructuredCloneInfo*>(closure);
   NS_ASSERTION(scInfo, "Must have scInfo!");
   nsCOMPtr<nsIXPConnectWrappedNative> wrappedNative;
   nsContentUtils::XPConnect()->
     GetWrappedNativeOfJSObject(cx, obj, getter_AddRefs(wrappedNative));
   if (wrappedNative) {
     uint32_t scTag = 0;
     nsISupports* supports = wrappedNative->Native();
     nsCOMPtr<nsIDOMBlob> blob = do_QueryInterface(supports);
     if (blob) {
       scTag = SCTAG_DOM_BLOB;
     }
     nsCOMPtr<nsIDOMFileList> list = do_QueryInterface(supports);
     if (list) {
       scTag = SCTAG_DOM_FILELIST;
     }
     if (scTag) {
       return JS_WriteUint32Pair(writer, scTag, 0) &&
              JS_WriteBytes(writer, &supports, sizeof(supports)) &&
              scInfo->mEvent->StoreISupports(supports);
     }
   }
   const JSStructuredCloneCallbacks* runtimeCallbacks =
     js::GetContextStructuredCloneCallbacks(cx);
   if (runtimeCallbacks) {
     return runtimeCallbacks->write(cx, writer, obj, nullptr);
   }
   return false;
 }
 static bool
 PostMessageReadTransferStructuredClone(JSContext* aCx,
                                        JSStructuredCloneReader* reader,
                                        uint32_t tag, void* data,
                                        uint64_t unused,
                                        void* aClosure,
                                        JS::MutableHandle<JSObject*> returnObject)
 {
   StructuredCloneInfo* scInfo = static_cast<StructuredCloneInfo*>(aClosure);
   NS_ASSERTION(scInfo, "Must have scInfo!");
   if (tag == SCTAG_DOM_MAP_MESSAGEPORT) {
     MessagePort* port = static_cast<MessagePort*>(data);
     port->BindToOwner(scInfo->mPort->GetOwner());
     scInfo->mPorts.Put(port, nullptr);
     JS::Rooted<JSObject*> obj(aCx, port->WrapObject(aCx));
     if (JS_WrapObject(aCx, &obj)) {
       MOZ_ASSERT(port->GetOwner() == scInfo->mPort->GetOwner());
       returnObject.set(obj);
     }
     return true;
   }
   return false;
 }
 static bool
 PostMessageTransferStructuredClone(JSContext* aCx,
                                    JS::Handle<JSObject*> aObj,
                                    void* aClosure,
                                    uint32_t* aTag,
                                    JS::TransferableOwnership* aOwnership,
                                    void** aContent,
                                    uint64_t *aExtraData)
 {
   StructuredCloneInfo* scInfo = static_cast<StructuredCloneInfo*>(aClosure);
   NS_ASSERTION(scInfo, "Must have scInfo!");
   MessagePortBase *port = nullptr;
   nsresult rv = UNWRAP_OBJECT(MessagePort, aObj, port);
   if (NS_SUCCEEDED(rv)) {
     nsRefPtr<MessagePortBase> newPort;
     if (scInfo->mPorts.Get(port, getter_AddRefs(newPort))) {
       // No duplicate.
       return false;
     }
     newPort = port->Clone();
     scInfo->mPorts.Put(port, newPort);
     *aTag = SCTAG_DOM_MAP_MESSAGEPORT;
     *aOwnership = JS::SCTAG_TMO_CUSTOM;
     *aContent = newPort;
     *aExtraData = 0;
     return true;
   }
   return false;
 }
 static void
 PostMessageFreeTransferStructuredClone(uint32_t aTag, JS::TransferableOwnership aOwnership,
                                        void* aData,
                                        uint64_t aExtraData,
                                        void* aClosure)
 {
   StructuredCloneInfo* scInfo = static_cast<StructuredCloneInfo*>(aClosure);
   NS_ASSERTION(scInfo, "Must have scInfo!");
   if (aTag == SCTAG_DOM_MAP_MESSAGEPORT) {
     MOZ_ASSERT(aOwnership == JS::SCTAG_TMO_CUSTOM);
     nsRefPtr<MessagePort> port(static_cast<MessagePort*>(aData));
     scInfo->mPorts.Remove(port);
   }
 }
 JSStructuredCloneCallbacks kPostMessageCallbacks = {
   PostMessageReadStructuredClone,
   PostMessageWriteStructuredClone,
   nullptr,
   PostMessageReadTransferStructuredClone,
   PostMessageTransferStructuredClone,
   PostMessageFreeTransferStructuredClone
 };
 } // anonymous namespace
 static PLDHashOperator
 PopulateMessagePortList(MessagePortBase* aKey, MessagePortBase* aValue, void* aClosure)
 {
   nsTArray<nsRefPtr<MessagePortBase> > *array =
     static_cast<nsTArray<nsRefPtr<MessagePortBase> > *>(aClosure);
   array->AppendElement(aKey);
   return PL_DHASH_NEXT;
 }
 NS_IMETHODIMP
 PostMessageRunnable::Run()
 {
   MOZ_ASSERT(mPort);
   // Get the JSContext for the target window
   nsCOMPtr<nsIScriptGlobalObject> sgo = do_QueryInterface(mPort->GetOwner());
   NS_ENSURE_STATE(sgo);
   nsCOMPtr<nsIScriptContext> scriptContext = sgo->GetContext();
   AutoPushJSContext cx(scriptContext ? scriptContext->GetNativeContext()
                                      : nsContentUtils::GetSafeJSContext());
   MOZ_ASSERT(cx);
   // Deserialize the structured clone data
   JS::Rooted<JS::Value> messageData(cx);
   StructuredCloneInfo scInfo;
   scInfo.mEvent = this;
   scInfo.mPort = mPort;
   if (!mBuffer.read(cx, &messageData, &kPostMessageCallbacks, &scInfo)) {
     return NS_ERROR_DOM_DATA_CLONE_ERR;
   }
   // Create the event
   nsCOMPtr<mozilla::dom::EventTarget> eventTarget =
     do_QueryInterface(mPort->GetOwner());
   nsRefPtr<MessageEvent> event =
     new MessageEvent(eventTarget, nullptr, nullptr);
   event->InitMessageEvent(NS_LITERAL_STRING("message"), false /* non-bubbling */,
                           false /* cancelable */, messageData, EmptyString(),
                           EmptyString(), nullptr);
   event->SetTrusted(true);
   event->SetSource(mPort);
   nsTArray<nsRefPtr<MessagePortBase> > ports;
   scInfo.mPorts.EnumerateRead(PopulateMessagePortList, &ports);
   event->SetPorts(new MessagePortList(static_cast<dom::Event*>(event.get()), ports));
   bool status;
   mPort->DispatchEvent(static_cast<dom::Event*>(event.get()), &status);
   return status ? NS_OK : NS_ERROR_FAILURE;
 }
 MessagePortBase::MessagePortBase(nsPIDOMWindow* aWindow)
   : DOMEventTargetHelper(aWindow)
 {
   // SetIsDOMBinding() is called by DOMEventTargetHelper's ctor.
 }
 MessagePortBase::MessagePortBase()
 {
   SetIsDOMBinding();
 }
 NS_IMPL_CYCLE_COLLECTION_CLASS(MessagePort)
 NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(MessagePort,
                                                 DOMEventTargetHelper)
   NS_IMPL_CYCLE_COLLECTION_UNLINK(mEntangledPort)
   // Custom unlink loop because this array contains nsRunnable objects
   // which are not cycle colleactable.
   while (!tmp->mMessageQueue.IsEmpty()) {
     NS_IMPL_CYCLE_COLLECTION_UNLINK(mMessageQueue[0]->mPort);
     NS_IMPL_CYCLE_COLLECTION_UNLINK(mMessageQueue[0]->mSupportsArray);
     tmp->mMessageQueue.RemoveElementAt(0);
   }
   if (tmp->mDispatchRunnable) {
     NS_IMPL_CYCLE_COLLECTION_UNLINK(mDispatchRunnable->mPort);
   }
 NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(MessagePort,
                                                   DOMEventTargetHelper)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mEntangledPort)
   // Custom unlink loop because this array contains nsRunnable objects
   // which are not cycle colleactable.
   for (uint32_t i = 0, len = tmp->mMessageQueue.Length(); i < len; ++i) {
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMessageQueue[i]->mPort);
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mMessageQueue[i]->mSupportsArray);
   }
   if (tmp->mDispatchRunnable) {
     NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mDispatchRunnable->mPort);
   }
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(MessagePort)
 NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
 NS_IMPL_ADDREF_INHERITED(MessagePort, DOMEventTargetHelper)
 NS_IMPL_RELEASE_INHERITED(MessagePort, DOMEventTargetHelper)
 MessagePort::MessagePort(nsPIDOMWindow* aWindow)
   : MessagePortBase(aWindow)
   , mMessageQueueEnabled(false)
 {
 }
 MessagePort::~MessagePort()
 {
   Close();
 }
 JSObject*
 MessagePort::WrapObject(JSContext* aCx)
 {
   return MessagePortBinding::Wrap(aCx, this);
 }
 void
 MessagePort::PostMessageMoz(JSContext* aCx, JS::Handle<JS::Value> aMessage,
                             const Optional<Sequence<JS::Value>>& aTransferable,
                             ErrorResult& aRv)
 {
   nsRefPtr<PostMessageRunnable> event = new PostMessageRunnable();
   // We *must* clone the data here, or the JS::Value could be modified
   // by script
   StructuredCloneInfo scInfo;
   scInfo.mEvent = event;
   scInfo.mPort = this;
   JS::Rooted<JS::Value> transferable(aCx, JS::UndefinedValue());
   if (aTransferable.WasPassed()) {
     const Sequence<JS::Value>& realTransferable = aTransferable.Value();
     // The input sequence only comes from the generated bindings code, which
     // ensures it is rooted.
     JS::HandleValueArray elements =
       JS::HandleValueArray::fromMarkedLocation(realTransferable.Length(),
                                                realTransferable.Elements());
     JSObject* array =
       JS_NewArrayObject(aCx, elements);
     if (!array) {
       aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
       return;
     }
     transferable.setObject(*array);
   }
   if (!event->Buffer().write(aCx, aMessage, transferable,
                              &kPostMessageCallbacks, &scInfo)) {
     aRv.Throw(NS_ERROR_DOM_DATA_CLONE_ERR);
     return;
   }
   if (!mEntangledPort) {
     return;
   }
   mEntangledPort->mMessageQueue.AppendElement(event);
   mEntangledPort->Dispatch();
 }
 void
 MessagePort::Start()
 {
   if (mMessageQueueEnabled) {
     return;
   }
   mMessageQueueEnabled = true;
   Dispatch();
 }
 void
 MessagePort::Dispatch()
 {
   if (!mMessageQueueEnabled || mMessageQueue.IsEmpty() || mDispatchRunnable) {
     return;
   }
   nsRefPtr<PostMessageRunnable> event = mMessageQueue.ElementAt(0);
   mMessageQueue.RemoveElementAt(0);
   event->Dispatch(this);
   mDispatchRunnable = new DispatchEventRunnable(this);
   NS_DispatchToCurrentThread(mDispatchRunnable);
 }
 void
 MessagePort::Close()
 {
   if (!mEntangledPort) {
     return;
   }
   // This avoids loops.
   nsRefPtr<MessagePort> port = mEntangledPort;
   mEntangledPort = nullptr;
   // Let's disentangle the 2 ports symmetrically.
   port->Close();
 }
 EventHandlerNonNull*
 MessagePort::GetOnmessage()
 {
   if (NS_IsMainThread()) {
     return GetEventHandler(nsGkAtoms::onmessage, EmptyString());
   }
   return GetEventHandler(nullptr, NS_LITERAL_STRING("message"));
 }
 void
 MessagePort::SetOnmessage(EventHandlerNonNull* aCallback)
 {
   if (NS_IsMainThread()) {
     SetEventHandler(nsGkAtoms::onmessage, EmptyString(), aCallback);
   } else {
     SetEventHandler(nullptr, NS_LITERAL_STRING("message"), aCallback);
   }
   // When using onmessage, the call to start() is implied.
   Start();
 }
 void
 MessagePort::Entangle(MessagePort* aMessagePort)
 {
   MOZ_ASSERT(aMessagePort);
   MOZ_ASSERT(aMessagePort != this);
   Close();
   mEntangledPort = aMessagePort;
 }
 already_AddRefed<MessagePortBase>
 MessagePort::Clone()
 {
   nsRefPtr<MessagePort> newPort = new MessagePort(nullptr);
   // Move all the events in the port message queue of original port.
   newPort->mMessageQueue.SwapElements(mMessageQueue);
   if (mEntangledPort) {
     nsRefPtr<MessagePort> port = mEntangledPort;
     mEntangledPort = nullptr;
     newPort->Entangle(port);
     port->Entangle(newPort);
   }
   return newPort.forget();
 }
 } // namespace dom
 } // namespace mozilla

The Tor Browser / annotate

dom/base/MessagePort.cpp@b8a032363ba2 (annotated)

dom/base/MessagePort.cpp