gecko-dev/dom/base/MessagePort.cpp

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C++

/* -*- 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/BlobBinding.h"
#include "mozilla/dom/Event.h"
#include "mozilla/dom/File.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 "ScriptSettings.h"
#include "nsIDocument.h"
#include "nsIDOMFileList.h"
#include "nsIPresShell.h"
namespace mozilla {
namespace dom {
class DispatchEventRunnable : public nsRunnable
{
friend class MessagePort;
public:
explicit 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)
{
StructuredCloneInfo* scInfo = static_cast<StructuredCloneInfo*>(closure);
NS_ASSERTION(scInfo, "Must have scInfo!");
if (tag == SCTAG_DOM_BLOB) {
NS_ASSERTION(!data, "Data should be empty");
// What we get back from the reader is a FileImpl.
// From that we create a new File.
FileImpl* blobImpl;
if (JS_ReadBytes(reader, &blobImpl, sizeof(blobImpl))) {
MOZ_ASSERT(blobImpl);
// nsRefPtr<File> needs to go out of scope before toObjectOrNull() is
// called because the static analysis thinks dereferencing XPCOM objects
// can GC (because in some cases it can!), and a return statement with a
// JSObject* type means that JSObject* is on the stack as a raw pointer
// while destructors are running.
JS::Rooted<JS::Value> val(cx);
{
nsRefPtr<File> blob = new File(scInfo->mPort->GetParentObject(),
blobImpl);
if (!WrapNewBindingObject(cx, blob, &val)) {
return nullptr;
}
}
return &val.toObject();
}
}
if (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 val.toObjectOrNull();
}
}
}
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!");
// See if this is a File/Blob object.
{
File* blob = nullptr;
if (NS_SUCCEEDED(UNWRAP_OBJECT(Blob, obj, blob))) {
FileImpl* blobImpl = blob->Impl();
if (JS_WriteUint32Pair(writer, SCTAG_DOM_BLOB, 0) &&
JS_WriteBytes(writer, &blobImpl, sizeof(blobImpl))) {
scInfo->mEvent->StoreISupports(blobImpl);
return true;
}
}
}
nsCOMPtr<nsIXPConnectWrappedNative> wrappedNative;
nsContentUtils::XPConnect()->
GetWrappedNativeOfJSObject(cx, obj, getter_AddRefs(wrappedNative));
if (wrappedNative) {
uint32_t scTag = 0;
nsISupports* supports = wrappedNative->Native();
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 (!obj || !JS_WrapObject(aCx, &obj)) {
return false;
}
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);
AutoJSAPI jsapi;
if (NS_WARN_IF(!jsapi.Init(mPort->GetParentObject()))) {
return NS_ERROR_UNEXPECTED;
}
JSContext* cx = jsapi.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)
{
}
MessagePortBase::MessagePortBase()
{
}
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