layout/base/nsFrameManager.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 /* Owns the frame tree and provides APIs to manipulate it */
   8
   9 #ifndef _nsFrameManager_h_
  10 #define _nsFrameManager_h_
  11
  12 #include "nsDebug.h"
  13 #include "mozilla/Attributes.h"
  14 #include "nsFrameList.h"
  15
  16 class nsContainerFrame;
  17 class nsIFrame;
  18 class nsILayoutHistoryState;
  19 class nsPlaceholderFrame;
  20 class nsWindowSizes;
  21
  22 namespace mozilla {
  23 struct FrameDestroyContext;
  24 class PresShell;
  25 }  // namespace mozilla
  26
  27 /**
  28  * Frame manager interface. The frame manager owns the frame tree model, and
  29  * handles structural manipulations to it, such as appending and inserting a
  30  * list of frames to a parent frame, or removing a child frame from a parent
  31  * frame.
  32  */
  33 class nsFrameManager {
  34  public:
  35   using DestroyContext = mozilla::FrameDestroyContext;
  36
  37   explicit nsFrameManager(mozilla::PresShell* aPresShell)
  38       : mPresShell(aPresShell), mRootFrame(nullptr) {
  39     MOZ_ASSERT(mPresShell, "need a pres shell");
  40   }
  41   ~nsFrameManager();
  42
  43   /*
  44    * Gets and sets the root frame (typically the viewport). The lifetime of the
  45    * root frame is controlled by the frame manager. When the frame manager is
  46    * destroyed, it destroys the entire frame hierarchy.
  47    */
  48   nsIFrame* GetRootFrame() const { return mRootFrame; }
  49   void SetRootFrame(nsIFrame* aRootFrame) {
  50     NS_ASSERTION(!mRootFrame, "already have a root frame");
  51     mRootFrame = aRootFrame;
  52   }
  53
  54   /*
  55    * After Destroy is called, it is an error to call any FrameManager methods.
  56    * Destroy should be called when the frame tree managed by the frame
  57    * manager is no longer being displayed.
  58    */
  59   void Destroy();
  60
  61   // Functions for manipulating the frame model
  62   void AppendFrames(nsContainerFrame* aParentFrame,
  63                     mozilla::FrameChildListID aListID,
  64                     nsFrameList&& aFrameList);
  65
  66   void InsertFrames(nsContainerFrame* aParentFrame,
  67                     mozilla::FrameChildListID aListID, nsIFrame* aPrevFrame,
  68                     nsFrameList&& aFrameList);
  69
  70   void RemoveFrame(DestroyContext&, mozilla::FrameChildListID, nsIFrame*);
  71
  72   /*
  73    * Capture/restore frame state for the frame subtree rooted at aFrame.
  74    * aState is the document state storage object onto which each frame
  75    * stores its state.  Callers of CaptureFrameState are responsible for
  76    * traversing next continuations of special siblings of aFrame as
  77    * needed; this method will only work with actual frametree descendants
  78    * of aFrame.
  79    */
  80
  81   void CaptureFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  82
  83   void RestoreFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  84
  85   /*
  86    * Add/restore state for one frame
  87    */
  88   void CaptureFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  89
  90   void RestoreFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  91
  92   void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
  93
  94  protected:
  95   // weak link, because the pres shell owns us
  96   mozilla::PresShell* MOZ_NON_OWNING_REF mPresShell;
  97   nsIFrame* mRootFrame;
  98 };
  99
 100 #endif