/* -*- 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/. */

#ifndef mozilla_image_IProgressObserver_h

#define mozilla_image_IProgressObserver_h

#include "mozilla/WeakPtr.h"

#include "nsISupports.h"

#include "nsRect.h"

class nsIEventTarget;

namespace mozilla {

namespace image {

/**

 * An interface for observing changes to image state, as reported by

 * ProgressTracker.

 *

 * This is the ImageLib-internal version of imgINotificationObserver,

 * essentially, with implementation details that code outside of ImageLib

 * shouldn't see.

 *

 * XXX(seth): It's preferable to avoid adding anything to this interface if

 * possible.  In the long term, it would be ideal to get to a place where we can

 * just use the imgINotificationObserver interface internally as well.

 */

class IProgressObserver : public SupportsWeakPtr<IProgressObserver>

{

public:

  MOZ_DECLARE_WEAKREFERENCE_TYPENAME(IProgressObserver)

  // Subclasses may or may not be XPCOM classes, so we just require that they

  // implement AddRef and Release.

  NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING

  // imgINotificationObserver methods:

  virtual void Notify(int32_t aType, const nsIntRect* aRect = nullptr) = 0;

  virtual void OnLoadComplete(bool aLastPart) = 0;

  // Other, internal-only methods:

  virtual void SetHasImage() = 0;

  virtual bool NotificationsDeferred() const = 0;

  virtual void MarkPendingNotify() = 0;

  virtual void ClearPendingNotify() = 0;

  virtual already_AddRefed<nsIEventTarget> GetEventTarget() const

  {

    return nullptr;

  }

protected:

  virtual ~IProgressObserver() { }

};

} // namespace image

} // namespace mozilla

#endif // mozilla_image_IProgressObserver_h