layout/generic/ColumnSetWrapperFrame.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 https://mozilla.org/MPL/2.0/. */
   6
   7 // A frame for CSS multi-column layout that wraps nsColumnSetFrames and
   8 // column-span frames.
   9
  10 #ifndef mozilla_ColumnSetWrapperFrame_h
  11 #define mozilla_ColumnSetWrapperFrame_h
  12
  13 #include "nsBlockFrame.h"
  14
  15 namespace mozilla {
  16
  17 class PresShell;
  18
  19 // This class is a wrapper for nsColumnSetFrames and column-span frame.
  20 // Essentially, we divide the *original* nsColumnSetFrame into multiple
  21 // nsColumnSetFrames on the basis of the number and position of spanning
  22 // elements.
  23 //
  24 // This wrapper is necessary for implementing column-span as it allows us to
  25 // maintain each nsColumnSetFrame as an independent set of columns, and each
  26 // column-span element then becomes just a block level element.
  27 //
  28 class ColumnSetWrapperFrame final : public nsBlockFrame {
  29  public:
  30   NS_DECL_FRAMEARENA_HELPERS(ColumnSetWrapperFrame)
  31   NS_DECL_QUERYFRAME
  32
  33   friend nsBlockFrame* ::NS_NewColumnSetWrapperFrame(
  34       mozilla::PresShell* aPresShell, ComputedStyle* aStyle,
  35       nsFrameState aStateFlags);
  36
  37   void Init(nsIContent* aContent, nsContainerFrame* aParent,
  38             nsIFrame* aPrevInFlow) override;
  39
  40   nsContainerFrame* GetContentInsertionFrame() override;
  41
  42   void AppendDirectlyOwnedAnonBoxes(nsTArray<OwnedAnonBox>& aResult) override;
  43
  44 #ifdef DEBUG_FRAME_DUMP
  45   nsresult GetFrameName(nsAString& aResult) const override;
  46 #endif
  47
  48   void AppendFrames(ChildListID aListID, nsFrameList& aFrameList) override;
  49
  50   void InsertFrames(ChildListID aListID, nsIFrame* aPrevFrame,
  51                     const nsLineList::iterator* aPrevFrameLine,
  52                     nsFrameList& aFrameList) override;
  53
  54   void RemoveFrame(ChildListID aListID, nsIFrame* aOldFrame) override;
  55
  56   void MarkIntrinsicISizesDirty() override;
  57
  58   nscoord GetMinISize(gfxContext* aRenderingContext) override;
  59
  60   nscoord GetPrefISize(gfxContext* aRenderingContext) override;
  61
  62  private:
  63   explicit ColumnSetWrapperFrame(ComputedStyle* aStyle,
  64                                  nsPresContext* aPresContext);
  65   ~ColumnSetWrapperFrame() override = default;
  66
  67 #ifdef DEBUG
  68   static void AssertColumnSpanWrapperSubtreeIsSane(const nsIFrame* aFrame);
  69
  70   // True if frame constructor has finished building this frame and all of
  71   // its descendants.
  72   bool mFinishedBuildingColumns = false;
  73 #endif
  74 };
  75
  76 }  // namespace mozilla
  77
  78 #endif  // mozilla_ColumnSetWrapperFrame_h