third_party/WebKit/Source/modules/encryptedmedia/MediaKeySession.h

/*
 * Copyright (C) 2013 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 INC. AND ITS CONTRIBUTORS ``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 INC. OR ITS 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 MediaKeySession_h
#define MediaKeySession_h

#include "bindings/core/v8/ActiveScriptWrappable.h"
#include "bindings/core/v8/ScriptPromiseProperty.h"
#include "core/dom/ContextLifecycleObserver.h"
#include "core/dom/DOMArrayPiece.h"
#include "modules/EventTargetModules.h"
#include "modules/encryptedmedia/MediaKeyStatusMap.h"
#include "platform/Timer.h"
#include "platform/heap/Handle.h"
#include "public/platform/WebContentDecryptionModuleSession.h"
#include "public/platform/WebEncryptedMediaTypes.h"
#include <memory>

namespace blink {

class DOMException;
class GenericEventQueue;
class MediaKeys;

// References are held by JS only. However, even if all JS references are
// dropped, it won't be garbage collected until close event received or
// MediaKeys goes away (as determined by a WeakMember reference). This allows
// the CDM to continue to fire events for this session, as long as the session
// is open.
//
// WeakMember<MediaKeys> is used instead of having MediaKeys and MediaKeySession
// keep references to each other, and then having to inform the other object
// when it gets destroyed. When the Oilpan garbage collector determines that
// only WeakMember<> references remain to the MediaKeys object, the MediaKeys
// object will be finalized and the WeakMember<> references will be cleared
// out(zeroed) by the garbage collector.
//
// Because this object controls the lifetime of the
// WebContentDecryptionModuleSession, it may outlive any JavaScript references
// as long as the MediaKeys object is alive.
// The WebContentDecryptionModuleSession has the same lifetime as this object.
class MediaKeySession final
    : public EventTargetWithInlineData,
      public ActiveScriptWrappable<MediaKeySession>,
      public ContextLifecycleObserver,
      private WebContentDecryptionModuleSession::Client {
  DEFINE_WRAPPERTYPEINFO();
  USING_GARBAGE_COLLECTED_MIXIN(MediaKeySession);
  USING_PRE_FINALIZER(MediaKeySession, dispose);

 public:
  static MediaKeySession* create(ScriptState*,
                                 MediaKeys*,
                                 WebEncryptedMediaSessionType);

  ~MediaKeySession() override;

  String sessionId() const;
  double expiration() const { return m_expiration; }
  ScriptPromise closed(ScriptState*);
  MediaKeyStatusMap* keyStatuses();
  DEFINE_ATTRIBUTE_EVENT_LISTENER(keystatuseschange);
  DEFINE_ATTRIBUTE_EVENT_LISTENER(message);

  ScriptPromise generateRequest(ScriptState*,
                                const String& initDataType,
                                const DOMArrayPiece& initData);
  ScriptPromise load(ScriptState*, const String& sessionId);
  ScriptPromise update(ScriptState*, const DOMArrayPiece& response);
  ScriptPromise close(ScriptState*);
  ScriptPromise remove(ScriptState*);

  // EventTarget
  const AtomicString& interfaceName() const override;
  ExecutionContext* getExecutionContext() const override;

  // ScriptWrappable
  bool hasPendingActivity() const final;

  // ContextLifecycleObserver
  void contextDestroyed(ExecutionContext*) override;

  DECLARE_VIRTUAL_TRACE();

 private:
  class PendingAction;
  friend class NewSessionResultPromise;
  friend class LoadSessionResultPromise;

  MediaKeySession(ScriptState*, MediaKeys*, WebEncryptedMediaSessionType);
  void dispose();

  void actionTimerFired(TimerBase*);

  // The following perform the asynchronous part of the command referenced.
  void generateRequestTask(ContentDecryptionModuleResult*,
                           WebEncryptedMediaInitDataType,
                           DOMArrayBuffer* initDataBuffer);
  void finishGenerateRequest();
  void loadTask(ContentDecryptionModuleResult*, const String& sessionId);
  void finishLoad();
  void updateTask(ContentDecryptionModuleResult*,
                  DOMArrayBuffer* sanitizedResponse);
  void closeTask(ContentDecryptionModuleResult*);
  void removeTask(ContentDecryptionModuleResult*);

  // WebContentDecryptionModuleSession::Client
  void message(MessageType,
               const unsigned char* message,
               size_t messageLength) override;
  void close() override;
  void expirationChanged(double updatedExpiryTimeInMS) override;
  void keysStatusesChange(const WebVector<WebEncryptedMediaKeyInformation>&,
                          bool hasAdditionalUsableKey) override;

  Member<GenericEventQueue> m_asyncEventQueue;
  std::unique_ptr<WebContentDecryptionModuleSession> m_session;

  // Used to determine if MediaKeys is still active.
  WeakMember<MediaKeys> m_mediaKeys;

  // Session properties.
  WebEncryptedMediaSessionType m_sessionType;
  double m_expiration;
  Member<MediaKeyStatusMap> m_keyStatusesMap;

  // Session states.
  bool m_isUninitialized;
  bool m_isCallable;
  bool m_isClosed;  // Is the CDM finished with this session?

  // Keep track of the closed promise.
  typedef ScriptPromiseProperty<Member<MediaKeySession>,
                                ToV8UndefinedGenerator,
                                Member<DOMException>>
      ClosedPromise;
  Member<ClosedPromise> m_closedPromise;

  HeapDeque<Member<PendingAction>> m_pendingActions;
  TaskRunnerTimer<MediaKeySession> m_actionTimer;
};

}  // namespace blink

#endif  // MediaKeySession_h