/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* 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/. */ /* table of images used in a document, for batch locking/unlocking and * animating */ #ifndef mozilla_dom_ImageTracker #define mozilla_dom_ImageTracker #include "nsDataHashtable.h" #include "nsHashKeys.h" class imgIRequest; namespace mozilla { namespace dom { /* * Image Tracking * * Style and content images register their imgIRequests with their document's * image tracker, so that we can efficiently tell all descendant images when * they are and are not visible. When an image is on-screen, we want to call * LockImage() on it so that it doesn't do things like discarding frame data * to save memory. The PresShell informs its document's image tracker whether * its images should be locked or not via SetLockingState(). * * See bug 512260. */ class ImageTracker { public: ImageTracker(); ImageTracker(const ImageTracker&) = delete; ImageTracker& operator=(const ImageTracker&) = delete; NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageTracker) nsresult Add(imgIRequest* aImage); enum { REQUEST_DISCARD = 0x1 }; nsresult Remove(imgIRequest* aImage, uint32_t aFlags = 0); // Makes the images on this document locked/unlocked. By default, the locking // state is unlocked/false. nsresult SetLockingState(bool aLocked); // Makes the images on this document capable of having their animation // active or suspended. An Image will animate as long as at least one of its // owning Documents needs it to animate; otherwise it can suspend. void SetAnimatingState(bool aAnimating); void RequestDiscardAll(); private: ~ImageTracker(); nsDataHashtable<nsPtrHashKey<imgIRequest>, uint32_t> mImages; bool mLocking; bool mAnimating; }; } // namespace dom } // namespace mozilla #endif // mozilla_dom_ImageTracker