зеркало из https://github.com/mozilla/gecko-dev.git
70 строки
2.0 KiB
C++
70 строки
2.0 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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/* table of images used in a document, for batch locking/unlocking and
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* animating */
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#ifndef mozilla_dom_ImageTracker
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#define mozilla_dom_ImageTracker
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#include "nsDataHashtable.h"
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#include "nsHashKeys.h"
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class imgIRequest;
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namespace mozilla {
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namespace dom {
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/*
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* Image Tracking
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*
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* Style and content images register their imgIRequests with their document's
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* image tracker, so that we can efficiently tell all descendant images when
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* they are and are not visible. When an image is on-screen, we want to call
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* LockImage() on it so that it doesn't do things like discarding frame data
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* to save memory. The PresShell informs its document's image tracker whether
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* its images should be locked or not via SetLockingState().
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*
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* See bug 512260.
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*/
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class ImageTracker
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{
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public:
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ImageTracker();
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ImageTracker(const ImageTracker&) = delete;
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ImageTracker& operator=(const ImageTracker&) = delete;
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NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ImageTracker)
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nsresult Add(imgIRequest* aImage);
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enum { REQUEST_DISCARD = 0x1 };
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nsresult Remove(imgIRequest* aImage, uint32_t aFlags = 0);
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// Makes the images on this document locked/unlocked. By default, the locking
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// state is unlocked/false.
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nsresult SetLockingState(bool aLocked);
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// Makes the images on this document capable of having their animation
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// active or suspended. An Image will animate as long as at least one of its
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// owning Documents needs it to animate; otherwise it can suspend.
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void SetAnimatingState(bool aAnimating);
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void RequestDiscardAll();
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private:
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~ImageTracker();
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nsDataHashtable<nsPtrHashKey<imgIRequest>, uint32_t> mImages;
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bool mLocking;
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bool mAnimating;
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};
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} // namespace dom
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} // namespace mozilla
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#endif // mozilla_dom_ImageTracker
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