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 class PresShell;
  24 }  // namespace mozilla
  25
  26 /**
  27  * Frame manager interface. The frame manager owns the frame tree model, and
  28  * handles structural manipulations to it, such as appending and inserting a
  29  * list of frames to a parent frame, or removing a child frame from a parent
  30  * frame.
  31  */
  32 class nsFrameManager {
  33  public:
  34   explicit nsFrameManager(mozilla::PresShell* aPresShell)
  35       : mPresShell(aPresShell), mRootFrame(nullptr) {
  36     MOZ_ASSERT(mPresShell, "need a pres shell");
  37   }
  38   ~nsFrameManager();
  39
  40   /*
  41    * Gets and sets the root frame (typically the viewport). The lifetime of the
  42    * root frame is controlled by the frame manager. When the frame manager is
  43    * destroyed, it destroys the entire frame hierarchy.
  44    */
  45   nsIFrame* GetRootFrame() const { return mRootFrame; }
  46   void SetRootFrame(nsIFrame* aRootFrame) {
  47     NS_ASSERTION(!mRootFrame, "already have a root frame");
  48     mRootFrame = aRootFrame;
  49   }
  50
  51   /*
  52    * After Destroy is called, it is an error to call any FrameManager methods.
  53    * Destroy should be called when the frame tree managed by the frame
  54    * manager is no longer being displayed.
  55    */
  56   void Destroy();
  57
  58   // Functions for manipulating the frame model
  59   void AppendFrames(nsContainerFrame* aParentFrame,
  60                     mozilla::FrameChildListID aListID,
  61                     nsFrameList&& aFrameList);
  62
  63   void InsertFrames(nsContainerFrame* aParentFrame,
  64                     mozilla::FrameChildListID aListID, nsIFrame* aPrevFrame,
  65                     nsFrameList&& aFrameList);
  66
  67   void RemoveFrame(mozilla::FrameChildListID aListID, nsIFrame* aOldFrame);
  68
  69   /*
  70    * Capture/restore frame state for the frame subtree rooted at aFrame.
  71    * aState is the document state storage object onto which each frame
  72    * stores its state.  Callers of CaptureFrameState are responsible for
  73    * traversing next continuations of special siblings of aFrame as
  74    * needed; this method will only work with actual frametree descendants
  75    * of aFrame.
  76    */
  77
  78   void CaptureFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  79
  80   void RestoreFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  81
  82   /*
  83    * Add/restore state for one frame
  84    */
  85   void CaptureFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  86
  87   void RestoreFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
  88
  89   void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
  90
  91  protected:
  92   // weak link, because the pres shell owns us
  93   mozilla::PresShell* MOZ_NON_OWNING_REF mPresShell;
  94   nsIFrame* mRootFrame;
  95 };
  96
  97 #endif