third_party/WebKit/Source/core/dom/MessagePort.h

/*
 * 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.
 *
 */

#ifndef MessagePort_h
#define MessagePort_h

#include "bindings/core/v8/ActiveScriptWrappable.h"
#include "bindings/core/v8/SerializedScriptValue.h"
#include "core/CoreExport.h"
#include "core/dom/ActiveDOMObject.h"
#include "core/events/EventListener.h"
#include "core/events/EventTarget.h"
#include "public/platform/WebMessagePortChannel.h"
#include "public/platform/WebMessagePortChannelClient.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefPtr.h"
#include "wtf/Vector.h"
#include <memory>

namespace blink {

class ExceptionState;
class ExecutionContext;
class MessagePort;
class ScriptState;
class SerializedScriptValue;

// Not to be confused with WebMessagePortChannelArray; this one uses Vector and
// std::unique_ptr instead of WebVector and raw pointers.
typedef Vector<WebMessagePortChannelUniquePtr, 1> MessagePortChannelArray;

class CORE_EXPORT MessagePort : public EventTargetWithInlineData,
                                public ActiveScriptWrappable,
                                public ActiveDOMObject,
                                public WebMessagePortChannelClient {
  DEFINE_WRAPPERTYPEINFO();
  USING_GARBAGE_COLLECTED_MIXIN(MessagePort);

 public:
  static MessagePort* create(ExecutionContext&);
  ~MessagePort() override;

  void postMessage(ExecutionContext*,
                   PassRefPtr<SerializedScriptValue> message,
                   const MessagePortArray&,
                   ExceptionState&);

  void start();
  void close();

  void entangle(WebMessagePortChannelUniquePtr);
  WebMessagePortChannelUniquePtr disentangle();

  // Returns nullptr if the passed-in array is nullptr/empty.
  static std::unique_ptr<WebMessagePortChannelArray>
      toWebMessagePortChannelArray(std::unique_ptr<MessagePortChannelArray>);

  // Returns an empty array if the passed array is empty.
  static MessagePortArray* toMessagePortArray(
      ExecutionContext*,
      const WebMessagePortChannelArray&);

  // Returns nullptr if there is an exception, or if the passed-in array is
  // nullptr/empty.
  static std::unique_ptr<MessagePortChannelArray>
  disentanglePorts(ExecutionContext*, const MessagePortArray&, ExceptionState&);

  // Returns an empty array if the passed array is nullptr/empty.
  static MessagePortArray* entanglePorts(
      ExecutionContext&,
      std::unique_ptr<MessagePortChannelArray>);

  bool started() const { return m_started; }

  const AtomicString& interfaceName() const override;
  ExecutionContext* getExecutionContext() const override {
    return ActiveDOMObject::getExecutionContext();
  }
  MessagePort* toMessagePort() override { return this; }

  // ScriptWrappable implementation.
  bool hasPendingActivity() const final;

  // ActiveDOMObject implementation.
  void stop() override { close(); }

  void setOnmessage(EventListener* listener) {
    setAttributeEventListener(EventTypeNames::message, listener);
    start();
  }
  EventListener* onmessage() {
    return getAttributeEventListener(EventTypeNames::message);
  }

  // A port starts out its life entangled, and remains entangled until it is
  // closed or is cloned.
  bool isEntangled() const { return !m_closed && !isNeutered(); }

  // A port gets neutered when it is transferred to a new owner via
  // postMessage().
  bool isNeutered() const { return !m_entangledChannel; }

  // For testing only: allows inspection of the entangled channel.
  WebMessagePortChannel* entangledChannelForTesting() const {
    return m_entangledChannel.get();
  }

  DECLARE_VIRTUAL_TRACE();

 protected:
  explicit MessagePort(ExecutionContext&);
  bool tryGetMessage(RefPtr<SerializedScriptValue>& message,
                     std::unique_ptr<MessagePortChannelArray>& channels);

 private:
  // WebMessagePortChannelClient implementation.
  void messageAvailable() override;
  void dispatchMessages();

  WebMessagePortChannelUniquePtr m_entangledChannel;

  bool m_started;
  bool m_closed;

  RefPtr<ScriptState> m_scriptStateForConversion;
};

}  // namespace blink

#endif  // MessagePort_h