image/IProgressObserver.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef mozilla_image_IProgressObserver_h
   7 #define mozilla_image_IProgressObserver_h
   8
   9 #include "mozilla/WeakPtr.h"
  10 #include "nsISupports.h"
  11 #include "nsRect.h"
  12
  13 class nsIEventTarget;
  14
  15 namespace mozilla {
  16 namespace image {
  17
  18 /**
  19  * An interface for observing changes to image state, as reported by
  20  * ProgressTracker.
  21  *
  22  * This is the ImageLib-internal version of imgINotificationObserver,
  23  * essentially, with implementation details that code outside of ImageLib
  24  * shouldn't see.
  25  *
  26  * XXX(seth): It's preferable to avoid adding anything to this interface if
  27  * possible.  In the long term, it would be ideal to get to a place where we can
  28  * just use the imgINotificationObserver interface internally as well.
  29  */
  30 class IProgressObserver : public SupportsWeakPtr {
  31  public:
  32   // Subclasses may or may not be XPCOM classes, so we just require that they
  33   // implement AddRef and Release.
  34   NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
  35
  36   // imgINotificationObserver methods:
  37   virtual void Notify(int32_t aType, const nsIntRect* aRect = nullptr) = 0;
  38   virtual void OnLoadComplete(bool aLastPart) = 0;
  39
  40   // Other, internal-only methods:
  41   virtual void SetHasImage() = 0;
  42   virtual bool NotificationsDeferred() const = 0;
  43   virtual void MarkPendingNotify() = 0;
  44   virtual void ClearPendingNotify() = 0;
  45
  46   virtual already_AddRefed<nsIEventTarget> GetEventTarget() const {
  47     return nullptr;
  48   }
  49
  50  protected:
  51   virtual ~IProgressObserver() = default;
  52 };
  53
  54 }  // namespace image
  55 }  // namespace mozilla
  56
  57 #endif  // mozilla_image_IProgressObserver_h