tor-browser

The Tor Browser
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nsFrameManager.h (3450B)

      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 "mozilla/Attributes.h"
     13 #include "nsDebug.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 class ViewportFrame;
     26 }  // namespace mozilla
     27 
     28 /**
     29 * Frame manager interface. The frame manager owns the frame tree model, and
     30 * handles structural manipulations to it, such as appending and inserting a
     31 * list of frames to a parent frame, or removing a child frame from a parent
     32 * frame.
     33 */
     34 class nsFrameManager {
     35 public:
     36  using DestroyContext = mozilla::FrameDestroyContext;
     37 
     38  explicit nsFrameManager(mozilla::PresShell* aPresShell)
     39      : mPresShell(aPresShell) {
     40    MOZ_ASSERT(mPresShell, "need a pres shell");
     41  }
     42  ~nsFrameManager();
     43 
     44  /*
     45   * Gets and sets the root frame (i.e. ViewportFrame). The lifetime of the
     46   * root frame is controlled by the frame manager. When the frame manager is
     47   * destroyed, it destroys the entire frame hierarchy.
     48   */
     49  nsIFrame* GetRootFrame() const { return mRootFrame; }
     50  void SetRootFrame(mozilla::ViewportFrame* aRootFrame);
     51 
     52  /*
     53   * After Destroy is called, it is an error to call any FrameManager methods.
     54   * Destroy should be called when the frame tree managed by the frame
     55   * manager is no longer being displayed.
     56   */
     57  void Destroy();
     58 
     59  // Functions for manipulating the frame model
     60  void AppendFrames(nsContainerFrame* aParentFrame,
     61                    mozilla::FrameChildListID aListID,
     62                    nsFrameList&& aFrameList);
     63 
     64  void InsertFrames(nsContainerFrame* aParentFrame,
     65                    mozilla::FrameChildListID aListID, nsIFrame* aPrevFrame,
     66                    nsFrameList&& aFrameList);
     67 
     68  void RemoveFrame(DestroyContext&, mozilla::FrameChildListID, nsIFrame*);
     69 
     70  /*
     71   * Capture/restore frame state for the frame subtree rooted at aFrame.
     72   * aState is the document state storage object onto which each frame
     73   * stores its state.  Callers of CaptureFrameState are responsible for
     74   * traversing next continuations of special siblings of aFrame as
     75   * needed; this method will only work with actual frametree descendants
     76   * of aFrame.
     77   */
     78 
     79  void CaptureFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
     80 
     81  void RestoreFrameState(nsIFrame* aFrame, nsILayoutHistoryState* aState);
     82 
     83  /*
     84   * Add/restore state for one frame
     85   */
     86  void CaptureFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
     87 
     88  void RestoreFrameStateFor(nsIFrame* aFrame, nsILayoutHistoryState* aState);
     89 
     90  void AddSizeOfIncludingThis(nsWindowSizes& aSizes) const;
     91 
     92 protected:
     93  // weak link, because the pres shell owns us
     94  mozilla::PresShell* MOZ_NON_OWNING_REF mPresShell;
     95 
     96  // Note: We use nsIFrame* instead of ViewportFrame* for mRootFrame to avoid
     97  // exposing ViewportFrame to the callers via GetRootFrame(), since they do not
     98  // depend on any ViewportFrame-specific APIs or details.
     99  nsIFrame* mRootFrame = nullptr;
    100 };
    101 
    102 #endif