text: /*
   * Copyright (C) 2008 Apple Inc. All Rights Reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   *
   */
  
  #include "core/dom/MessagePort.h"
  
  #include "bindings/core/v8/ExceptionState.h"
  #include "bindings/core/v8/ExceptionStatePlaceholder.h"
  #include "bindings/core/v8/SerializedScriptValue.h"
  #include "bindings/core/v8/SerializedScriptValueFactory.h"
  #include "core/dom/CrossThreadTask.h"
  #include "core/dom/ExceptionCode.h"
  #include "core/dom/ExecutionContext.h"
  #include "core/events/MessageEvent.h"
  #include "core/frame/LocalDOMWindow.h"
  #include "core/inspector/ConsoleMessage.h"
  #include "core/workers/WorkerGlobalScope.h"
  #include "public/platform/WebString.h"
  #include "wtf/Functional.h"
  #include "wtf/text/AtomicString.h"
  
  namespace blink {
  
  MessagePort* MessagePort::create(ExecutionContext& executionContext)
  {
      MessagePort* port = new MessagePort(executionContext);
      port->suspendIfNeeded();
      return port;
  }
  
  MessagePort::MessagePort(ExecutionContext& executionContext)
      : ActiveDOMObject(&executionContext)
      , m_started(false)
      , m_closed(false)
      , m_weakFactory(this)
  {
  }
  
  MessagePort::~MessagePort()
  {
      close();
      if (m_scriptStateForConversion)
          m_scriptStateForConversion->disposePerContextData();
  }
  
  void MessagePort::postMessage(ExecutionContext* context, PassRefPtr<SerializedScriptValue> message, const MessagePortArray* ports, ExceptionState& exceptionState)
  {
      if (!isEntangled())
          return;
      ASSERT(executionContext());
      ASSERT(m_entangledChannel);
  
      OwnPtr<MessagePortChannelArray> channels;
      // Make sure we aren't connected to any of the passed-in ports.
      if (ports) {
          for (unsigned i = 0; i < ports->size(); ++i) {
              MessagePort* dataPort = (*ports)[i];
              if (dataPort == this) {
                  exceptionState.throwDOMException(DataCloneError, "Port at index " + String::number(i) + " contains the source port.");
                  return;
              }
          }
          channels = MessagePort::disentanglePorts(context, ports, exceptionState);
          if (exceptionState.hadException())
              return;
      }
  
      if (message->containsTransferableArrayBuffer())
          executionContext()->addConsoleMessage(ConsoleMessage::create(JSMessageSource, WarningMessageLevel, "MessagePort cannot send an ArrayBuffer as a transferable object yet. See http://crbug.com/334408"));
  
      WebString messageString = message->toWireString();
      OwnPtr<WebMessagePortChannelArray> webChannels = toWebMessagePortChannelArray(channels.release());
      m_entangledChannel->postMessage(messageString, webChannels.leakPtr());
  }
  
  // static
  PassOwnPtr<WebMessagePortChannelArray> MessagePort::toWebMessagePortChannelArray(PassOwnPtr<MessagePortChannelArray> channels)
  {
      OwnPtr<WebMessagePortChannelArray> webChannels;
      if (channels && channels->size()) {
          webChannels = adoptPtr(new WebMessagePortChannelArray(channels->size()));
          for (size_t i = 0; i < channels->size(); ++i)
              (*webChannels)[i] = (*channels)[i].leakPtr();
      }
      return webChannels.release();
  }
  
  // static
  MessagePortArray* MessagePort::toMessagePortArray(ExecutionContext* context, const WebMessagePortChannelArray& webChannels)
  {
      MessagePortArray* ports = nullptr;
      if (!webChannels.isEmpty()) {
          OwnPtr<MessagePortChannelArray> channels = adoptPtr(new MessagePortChannelArray(webChannels.size()));
          for (size_t i = 0; i < webChannels.size(); ++i)
              (*channels)[i] = adoptPtr(webChannels[i]);
          ports = MessagePort::entanglePorts(*context, channels.release());
      }
      return ports;
  }
  
  PassOwnPtr<WebMessagePortChannel> MessagePort::disentangle()
  {
      ASSERT(m_entangledChannel);
      m_entangledChannel->setClient(0);
      return m_entangledChannel.release();
  }
  
  // Invoked to notify us that there are messages available for this port.
  // This code may be called from another thread, and so should not call any non-threadsafe APIs (i.e. should not call into the entangled channel or access mutable variables).
  void MessagePort::messageAvailable()
  {
      ASSERT(executionContext());
      executionContext()->postTask(BLINK_FROM_HERE, createCrossThreadTask(&MessagePort::dispatchMessages, m_weakFactory.createWeakPtr()));
  }
  
  void MessagePort::start()
  {
      // Do nothing if we've been cloned or closed.
      if (!isEntangled())
          return;
  
      ASSERT(executionContext());
      if (m_started)
          return;
  
      m_started = true;
      messageAvailable();
  }
  
  void MessagePort::close()
  {
      if (isEntangled())
          m_entangledChannel->setClient(0);
      m_closed = true;
  }
  
  void MessagePort::entangle(PassOwnPtr<WebMessagePortChannel> remote)
  {
      // Only invoked to set our initial entanglement.
      ASSERT(!m_entangledChannel);
      ASSERT(executionContext());
  
      m_entangledChannel = remote;
      m_entangledChannel->setClient(this);
  }
  
  const AtomicString& MessagePort::interfaceName() const
  {
      return EventTargetNames::MessagePort;
  }
  
  static bool tryGetMessageFrom(WebMessagePortChannel& webChannel, RefPtr<SerializedScriptValue>& message, OwnPtr<MessagePortChannelArray>& channels)
  {
      WebString messageString;
      WebMessagePortChannelArray webChannels;
      if (!webChannel.tryGetMessage(&messageString, webChannels))
          return false;
  
      if (webChannels.size()) {
          channels = adoptPtr(new MessagePortChannelArray(webChannels.size()));
          for (size_t i = 0; i < webChannels.size(); ++i)
              (*channels)[i] = adoptPtr(webChannels[i]);
      }
      message = SerializedScriptValueFactory::instance().createFromWire(messageString);
      return true;
  }
  
  bool MessagePort::tryGetMessage(RefPtr<SerializedScriptValue>& message, OwnPtr<MessagePortChannelArray>& channels)
  {
      if (!m_entangledChannel)
          return false;
      return tryGetMessageFrom(*m_entangledChannel, message, channels);
  }
  
  void MessagePort::dispatchMessages()
  {
      // Because close() doesn't cancel any in flight calls to dispatchMessages() we need to check if the port is still open before dispatch.
      if (m_closed)
          return;
  
      // Messages for contexts that are not fully active get dispatched too, but JSAbstractEventListener::handleEvent() doesn't call handlers for these.
      // The HTML5 spec specifies that any messages sent to a document that is not fully active should be dropped, so this behavior is OK.
      if (!started())
          return;
  
      RefPtr<SerializedScriptValue> message;
      OwnPtr<MessagePortChannelArray> channels;
      while (tryGetMessage(message, channels)) {
          // close() in Worker onmessage handler should prevent next message from dispatching.
          if (executionContext()->isWorkerGlobalScope() && toWorkerGlobalScope(executionContext())->isClosing())
              return;
  
          MessagePortArray* ports = MessagePort::entanglePorts(*executionContext(), channels.release());
          RefPtrWillBeRawPtr<Event> evt = MessageEvent::create(ports, message.release());
  
          dispatchEvent(evt.release());
      }
  }
  
  bool MessagePort::hasPendingActivity() const
  {
      // The spec says that entangled message ports should always be treated as if they have a strong reference.
      // We'll also stipulate that the queue needs to be open (if the app drops its reference to the port before start()-ing it, then it's not really entangled as it's unreachable).
      return m_started && isEntangled();
  }
  
  PassOwnPtr<MessagePortChannelArray> MessagePort::disentanglePorts(ExecutionContext* context, const MessagePortArray* ports, ExceptionState& exceptionState)
  {
      if (!ports || !ports->size())
          return nullptr;
  
      // HeapHashSet used to efficiently check for duplicates in the passed-in array.
      HeapHashSet<Member<MessagePort>> portSet;
  
      // Walk the incoming array - if there are any duplicate ports, or null ports or cloned ports, throw an error (per section 8.3.3 of the HTML5 spec).
      for (unsigned i = 0; i < ports->size(); ++i) {
          MessagePort* port = (*ports)[i];
          if (!port || port->isNeutered() || portSet.contains(port)) {
              String type;
              if (!port)
                  type = "null";
              else if (port->isNeutered())
                  type = "already neutered";
              else
                  type = "a duplicate";
              exceptionState.throwDOMException(DataCloneError, "Port at index "  + String::number(i) + " is " + type + ".");
              return nullptr;
          }
          portSet.add(port);
      }
  
      UseCounter::count(context, UseCounter::MessagePortsTransferred);
  
      // Passed-in ports passed validity checks, so we can disentangle them.
      OwnPtr<MessagePortChannelArray> portArray = adoptPtr(new MessagePortChannelArray(ports->size()));
      for (unsigned i = 0; i < ports->size(); ++i)
          (*portArray)[i] = (*ports)[i]->disentangle();
      return portArray.release();
  }
  
  MessagePortArray* MessagePort::entanglePorts(ExecutionContext& context, PassOwnPtr<MessagePortChannelArray> channels)
  {
      // https://html.spec.whatwg.org/multipage/comms.html#message-ports
      // |ports| should be an empty array, not null even when there is no ports.
      if (!channels || !channels->size())
          return new MessagePortArray;
  
      MessagePortArray* portArray = new MessagePortArray(channels->size());
      for (unsigned i = 0; i < channels->size(); ++i) {
          MessagePort* port = MessagePort::create(context);
          port->entangle((*channels)[i].release());
          (*portArray)[i] = port;
      }
      return portArray;
  }
  
  DEFINE_TRACE(MessagePort)
  {
      ActiveDOMObject::trace(visitor);
      RefCountedGarbageCollectedEventTargetWithInlineData<MessagePort>::trace(visitor);
  }
  
  v8::Isolate* MessagePort::scriptIsolate()
  {
      ASSERT(executionContext());
      return toIsolate(executionContext());
  }
  
  v8::Local<v8::Context> MessagePort::scriptContextForMessageConversion()
  {
      ASSERT(executionContext());
      if (!m_scriptStateForConversion) {
          v8::Isolate* isolate = scriptIsolate();
          m_scriptStateForConversion = ScriptState::create(v8::Context::New(isolate), DOMWrapperWorld::create(isolate));
      }
      return m_scriptStateForConversion->context();
  }
  
  } // namespace blink
  