layout/generic/nsGridContainerFrame.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 /* rendering object for CSS "display: grid | inline-grid" */
   8
   9 #ifndef nsGridContainerFrame_h___
  10 #define nsGridContainerFrame_h___
  11
  12 #include "mozilla/CSSOrderAwareFrameIterator.h"
  13 #include "mozilla/MathAlgorithms.h"
  14 #include "mozilla/Maybe.h"
  15 #include "mozilla/HashTable.h"
  16 #include "nsAtomHashKeys.h"
  17 #include "nsContainerFrame.h"
  18 #include "nsILineIterator.h"
  19
  20 namespace mozilla {
  21 class PresShell;
  22 namespace dom {
  23 class Grid;
  24 }
  25 }  // namespace mozilla
  26
  27 /**
  28  * Factory function.
  29  * @return a newly allocated nsGridContainerFrame (infallible)
  30  */
  31 nsContainerFrame* NS_NewGridContainerFrame(mozilla::PresShell* aPresShell,
  32                                            mozilla::ComputedStyle* aStyle);
  33
  34 namespace mozilla {
  35
  36 /**
  37  * The number of implicit / explicit tracks and their sizes.
  38  */
  39 struct ComputedGridTrackInfo {
  40   ComputedGridTrackInfo(
  41       uint32_t aNumLeadingImplicitTracks, uint32_t aNumExplicitTracks,
  42       uint32_t aStartFragmentTrack, uint32_t aEndFragmentTrack,
  43       nsTArray<nscoord>&& aPositions, nsTArray<nscoord>&& aSizes,
  44       nsTArray<uint32_t>&& aStates, nsTArray<bool>&& aRemovedRepeatTracks,
  45       uint32_t aRepeatFirstTrack,
  46       nsTArray<nsTArray<StyleCustomIdent>>&& aResolvedLineNames,
  47       bool aIsSubgrid, bool aIsMasonry)
  48       : mNumLeadingImplicitTracks(aNumLeadingImplicitTracks),
  49         mNumExplicitTracks(aNumExplicitTracks),
  50         mStartFragmentTrack(aStartFragmentTrack),
  51         mEndFragmentTrack(aEndFragmentTrack),
  52         mPositions(std::move(aPositions)),
  53         mSizes(std::move(aSizes)),
  54         mStates(std::move(aStates)),
  55         mRemovedRepeatTracks(std::move(aRemovedRepeatTracks)),
  56         mResolvedLineNames(std::move(aResolvedLineNames)),
  57         mRepeatFirstTrack(aRepeatFirstTrack),
  58         mIsSubgrid(aIsSubgrid),
  59         mIsMasonry(aIsMasonry) {}
  60   uint32_t mNumLeadingImplicitTracks;
  61   uint32_t mNumExplicitTracks;
  62   uint32_t mStartFragmentTrack;
  63   uint32_t mEndFragmentTrack;
  64   nsTArray<nscoord> mPositions;
  65   nsTArray<nscoord> mSizes;
  66   nsTArray<uint32_t> mStates;
  67   // Indicates if a track has been collapsed. This will be populated for each
  68   // track in the repeat(auto-fit) and repeat(auto-fill), even if there are no
  69   // collapsed tracks.
  70   nsTArray<bool> mRemovedRepeatTracks;
  71   // Contains lists of all line name lists, including the name lists inside
  72   // repeats. When a repeat(auto) track exists, the internal track names will
  73   // appear once each in this array.
  74   nsTArray<nsTArray<StyleCustomIdent>> mResolvedLineNames;
  75   uint32_t mRepeatFirstTrack;
  76   bool mIsSubgrid;
  77   bool mIsMasonry;
  78 };
  79
  80 struct ComputedGridLineInfo {
  81   explicit ComputedGridLineInfo(
  82       nsTArray<nsTArray<RefPtr<nsAtom>>>&& aNames,
  83       const nsTArray<RefPtr<nsAtom>>& aNamesBefore,
  84       const nsTArray<RefPtr<nsAtom>>& aNamesAfter,
  85       nsTArray<RefPtr<nsAtom>>&& aNamesFollowingRepeat)
  86       : mNames(std::move(aNames)),
  87         mNamesBefore(aNamesBefore.Clone()),
  88         mNamesAfter(aNamesAfter.Clone()),
  89         mNamesFollowingRepeat(std::move(aNamesFollowingRepeat)) {}
  90   nsTArray<nsTArray<RefPtr<nsAtom>>> mNames;
  91   nsTArray<RefPtr<nsAtom>> mNamesBefore;
  92   nsTArray<RefPtr<nsAtom>> mNamesAfter;
  93   nsTArray<RefPtr<nsAtom>> mNamesFollowingRepeat;
  94 };
  95 }  // namespace mozilla
  96
  97 class nsGridContainerFrame final : public nsContainerFrame,
  98                                    public nsILineIterator {
  99  public:
 100   NS_DECL_FRAMEARENA_HELPERS(nsGridContainerFrame)
 101   NS_DECL_QUERYFRAME
 102   using ComputedGridTrackInfo = mozilla::ComputedGridTrackInfo;
 103   using ComputedGridLineInfo = mozilla::ComputedGridLineInfo;
 104   using LogicalAxis = mozilla::LogicalAxis;
 105   using BaselineSharingGroup = mozilla::BaselineSharingGroup;
 106   using NamedArea = mozilla::StyleNamedArea;
 107
 108   template <typename T>
 109   using PerBaseline = mozilla::EnumeratedArray<BaselineSharingGroup, T, 2>;
 110
 111   template <typename T>
 112   using PerLogicalAxis = mozilla::EnumeratedArray<LogicalAxis, T, 2>;
 113
 114   // nsIFrame overrides
 115   void Reflow(nsPresContext* aPresContext, ReflowOutput& aDesiredSize,
 116               const ReflowInput& aReflowInput,
 117               nsReflowStatus& aStatus) override;
 118   void Init(nsIContent* aContent, nsContainerFrame* aParent,
 119             nsIFrame* aPrevInFlow) override;
 120   void DidSetComputedStyle(ComputedStyle* aOldStyle) override;
 121   nscoord GetMinISize(gfxContext* aRenderingContext) override;
 122   nscoord GetPrefISize(gfxContext* aRenderingContext) override;
 123   void MarkIntrinsicISizesDirty() override;
 124
 125   void BuildDisplayList(nsDisplayListBuilder* aBuilder,
 126                         const nsDisplayListSet& aLists) override;
 127
 128   Maybe<nscoord> GetNaturalBaselineBOffset(
 129       mozilla::WritingMode aWM, BaselineSharingGroup aBaselineGroup,
 130       BaselineExportContext) const override {
 131     if (StyleDisplay()->IsContainLayout() ||
 132         HasAnyStateBits(NS_STATE_GRID_SYNTHESIZE_BASELINE)) {
 133       return Nothing{};
 134     }
 135     return mozilla::Some(GetBBaseline(aBaselineGroup));
 136   }
 137
 138 #ifdef DEBUG_FRAME_DUMP
 139   nsresult GetFrameName(nsAString& aResult) const override;
 140   void ExtraContainerFrameInfo(nsACString& aTo) const override;
 141 #endif
 142
 143   // nsContainerFrame overrides
 144   bool DrainSelfOverflowList() override;
 145   void AppendFrames(ChildListID aListID, nsFrameList&& aFrameList) override;
 146   void InsertFrames(ChildListID aListID, nsIFrame* aPrevFrame,
 147                     const nsLineList::iterator* aPrevFrameLine,
 148                     nsFrameList&& aFrameList) override;
 149   void RemoveFrame(DestroyContext&, ChildListID, nsIFrame*) override;
 150   mozilla::StyleAlignFlags CSSAlignmentForAbsPosChild(
 151       const ReflowInput& aChildRI, LogicalAxis aLogicalAxis) const override;
 152
 153 #ifdef DEBUG
 154   void SetInitialChildList(ChildListID aListID,
 155                            nsFrameList&& aChildList) override;
 156 #endif
 157
 158   /**
 159    * Return the containing block for aChild which MUST be an abs.pos. child
 160    * of a grid container and that container must have been reflowed.
 161    */
 162   static const nsRect& GridItemCB(nsIFrame* aChild);
 163
 164   NS_DECLARE_FRAME_PROPERTY_DELETABLE(GridItemContainingBlockRect, nsRect)
 165
 166   /**
 167    * These properties are created by a call to
 168    * nsGridContainerFrame::GetGridFrameWithComputedInfo, typically from
 169    * Element::GetGridFragments.
 170    */
 171   NS_DECLARE_FRAME_PROPERTY_DELETABLE(GridColTrackInfo, ComputedGridTrackInfo)
 172   const ComputedGridTrackInfo* GetComputedTemplateColumns() {
 173     const ComputedGridTrackInfo* info = GetProperty(GridColTrackInfo());
 174     MOZ_ASSERT(info, "Property generation wasn't requested.");
 175     return info;
 176   }
 177
 178   NS_DECLARE_FRAME_PROPERTY_DELETABLE(GridRowTrackInfo, ComputedGridTrackInfo)
 179   const ComputedGridTrackInfo* GetComputedTemplateRows() {
 180     const ComputedGridTrackInfo* info = GetProperty(GridRowTrackInfo());
 181     MOZ_ASSERT(info, "Property generation wasn't requested.");
 182     return info;
 183   }
 184
 185   NS_DECLARE_FRAME_PROPERTY_DELETABLE(GridColumnLineInfo, ComputedGridLineInfo)
 186   const ComputedGridLineInfo* GetComputedTemplateColumnLines() {
 187     const ComputedGridLineInfo* info = GetProperty(GridColumnLineInfo());
 188     MOZ_ASSERT(info, "Property generation wasn't requested.");
 189     return info;
 190   }
 191
 192   NS_DECLARE_FRAME_PROPERTY_DELETABLE(GridRowLineInfo, ComputedGridLineInfo)
 193   const ComputedGridLineInfo* GetComputedTemplateRowLines() {
 194     const ComputedGridLineInfo* info = GetProperty(GridRowLineInfo());
 195     MOZ_ASSERT(info, "Property generation wasn't requested.");
 196     return info;
 197   }
 198
 199   /**
 200    * This property is set by the creation of a dom::Grid object, and cleared
 201    * during GC unlink. Since the Grid object manages the lifecycle, the property
 202    * itself is set without a destructor. The property is also cleared whenever
 203    * new grid computed info is generated during reflow, ensuring that we aren't
 204    * holding a stale dom::Grid object.
 205    */
 206   NS_DECLARE_FRAME_PROPERTY_WITHOUT_DTOR(GridFragmentInfo, mozilla::dom::Grid)
 207   mozilla::dom::Grid* GetGridFragmentInfo() {
 208     return GetProperty(GridFragmentInfo());
 209   }
 210
 211   using ImplicitNamedAreas =
 212       mozilla::HashMap<mozilla::AtomHashKey, NamedArea, mozilla::AtomHashKey>;
 213   NS_DECLARE_FRAME_PROPERTY_DELETABLE(ImplicitNamedAreasProperty,
 214                                       ImplicitNamedAreas)
 215   ImplicitNamedAreas* GetImplicitNamedAreas() const {
 216     return GetProperty(ImplicitNamedAreasProperty());
 217   }
 218
 219   using ExplicitNamedAreas = mozilla::StyleOwnedSlice<NamedArea>;
 220   NS_DECLARE_FRAME_PROPERTY_DELETABLE(ExplicitNamedAreasProperty,
 221                                       ExplicitNamedAreas)
 222   ExplicitNamedAreas* GetExplicitNamedAreas() const {
 223     return GetProperty(ExplicitNamedAreasProperty());
 224   }
 225
 226   using nsContainerFrame::IsMasonry;
 227
 228   /** Return true if this frame has masonry layout in any axis. */
 229   bool IsMasonry() const {
 230     return HasAnyStateBits(NS_STATE_GRID_IS_ROW_MASONRY |
 231                            NS_STATE_GRID_IS_COL_MASONRY);
 232   }
 233
 234   /** Return true if this frame is subgridded in its aAxis. */
 235   bool IsSubgrid(LogicalAxis aAxis) const {
 236     return HasAnyStateBits(aAxis == mozilla::LogicalAxis::Block
 237                                ? NS_STATE_GRID_IS_ROW_SUBGRID
 238                                : NS_STATE_GRID_IS_COL_SUBGRID);
 239   }
 240   bool IsColSubgrid() const { return IsSubgrid(mozilla::LogicalAxis::Inline); }
 241   bool IsRowSubgrid() const { return IsSubgrid(mozilla::LogicalAxis::Block); }
 242   /** Return true if this frame is subgridded in any axis. */
 243   bool IsSubgrid() const {
 244     return HasAnyStateBits(NS_STATE_GRID_IS_ROW_SUBGRID |
 245                            NS_STATE_GRID_IS_COL_SUBGRID);
 246   }
 247
 248   /** Return true if this frame has an item that is subgridded in our aAxis. */
 249   bool HasSubgridItems(LogicalAxis aAxis) const {
 250     return HasAnyStateBits(aAxis == mozilla::LogicalAxis::Block
 251                                ? NS_STATE_GRID_HAS_ROW_SUBGRID_ITEM
 252                                : NS_STATE_GRID_HAS_COL_SUBGRID_ITEM);
 253   }
 254   /** Return true if this frame has any subgrid items. */
 255   bool HasSubgridItems() const {
 256     return HasAnyStateBits(NS_STATE_GRID_HAS_ROW_SUBGRID_ITEM |
 257                            NS_STATE_GRID_HAS_COL_SUBGRID_ITEM);
 258   }
 259   /**
 260    * Return true if the grid item aChild should stretch in its aAxis (i.e. aAxis
 261    * is in the aChild's writing-mode).
 262    *
 263    * Note: this method does *not* consider the grid item's aspect-ratio and
 264    * natural size in the axis when the self-alignment value is 'normal' per
 265    * https://drafts.csswg.org/css-grid/#grid-item-sizing
 266    */
 267   bool GridItemShouldStretch(const nsIFrame* aChild, LogicalAxis aAxis) const;
 268
 269   /**
 270    * Returns true if aFrame forms an independent formatting context and hence
 271    * should be inhibited from being a subgrid (i.e. if the used value of
 272    * 'grid-template-{rows,columns}:subgrid' should be 'none').
 273    * https://drafts.csswg.org/css-grid-2/#subgrid-listing
 274    *
 275    * (Note this only makes sense to call if aFrame is itself either a grid
 276    * container frame or a wrapper frame for a grid container frame, e.g. a
 277    * scroll container frame for a scrollable grid.  Having said that, this is
 278    * technically safe to call on any non-null frame.)
 279    */
 280   static bool ShouldInhibitSubgridDueToIFC(const nsIFrame* aFrame);
 281
 282   /**
 283    * Return a container grid frame for the supplied frame, if available.
 284    * @return nullptr if aFrame has no grid container.
 285    */
 286   static nsGridContainerFrame* GetGridContainerFrame(nsIFrame* aFrame);
 287
 288   /**
 289    * Return a container grid frame, and ensure it has computed grid info
 290    * @return nullptr if aFrame has no grid container, or frame was destroyed
 291    * @note this might destroy layout/style data since it may flush layout
 292    */
 293   MOZ_CAN_RUN_SCRIPT_BOUNDARY
 294   static nsGridContainerFrame* GetGridFrameWithComputedInfo(nsIFrame* aFrame);
 295
 296   struct Subgrid;
 297   struct UsedTrackSizes;
 298   struct TrackSize;
 299   struct GridItemInfo;
 300   struct GridReflowInput;
 301   struct FindItemInGridOrderResult {
 302     // The first(last) item in (reverse) grid order.
 303     const GridItemInfo* mItem;
 304     // Does the above item span the first(last) track?
 305     bool mIsInEdgeTrack;
 306   };
 307
 308   /** Return our parent grid container; |this| MUST be a subgrid. */
 309   nsGridContainerFrame* ParentGridContainerForSubgrid() const;
 310
 311   // https://drafts.csswg.org/css-sizing/#constraints
 312   enum class SizingConstraint {
 313     MinContent,   // sizing under min-content constraint
 314     MaxContent,   // sizing under max-content constraint
 315     NoConstraint  // no constraint, used during Reflow
 316   };
 317
 318  protected:
 319   typedef mozilla::LogicalPoint LogicalPoint;
 320   typedef mozilla::LogicalRect LogicalRect;
 321   typedef mozilla::LogicalSize LogicalSize;
 322   typedef mozilla::WritingMode WritingMode;
 323   struct Grid;
 324   struct GridArea;
 325   class LineNameMap;
 326   struct LineRange;
 327   struct SharedGridData;
 328   struct SubgridFallbackTrackSizingFunctions;
 329   struct TrackSizingFunctions;
 330   struct Tracks;
 331   struct TranslatedLineRange;
 332   friend nsContainerFrame* NS_NewGridContainerFrame(
 333       mozilla::PresShell* aPresShell, ComputedStyle* aStyle);
 334   explicit nsGridContainerFrame(ComputedStyle* aStyle,
 335                                 nsPresContext* aPresContext)
 336       : nsContainerFrame(aStyle, aPresContext, kClassID),
 337         mCachedMinISize(NS_INTRINSIC_ISIZE_UNKNOWN),
 338         mCachedPrefISize(NS_INTRINSIC_ISIZE_UNKNOWN) {
 339     for (auto& perAxisBaseline : mBaseline) {
 340       for (auto& baseline : perAxisBaseline) {
 341         baseline = NS_INTRINSIC_ISIZE_UNKNOWN;
 342       }
 343     }
 344   }
 345
 346   /**
 347    * XXX temporary - move the ImplicitNamedAreas stuff to the style system.
 348    * The implicit area names that come from x-start .. x-end lines in
 349    * grid-template-columns / grid-template-rows are stored in this frame
 350    * property when needed, as a ImplicitNamedAreas* value.
 351    */
 352   void InitImplicitNamedAreas(const nsStylePosition* aStyle);
 353
 354   using LineNameList =
 355       const mozilla::StyleOwnedSlice<mozilla::StyleCustomIdent>;
 356   void AddImplicitNamedAreas(mozilla::Span<LineNameList>);
 357   using StyleLineNameListValue =
 358       const mozilla::StyleGenericLineNameListValue<mozilla::StyleInteger>;
 359   void AddImplicitNamedAreas(mozilla::Span<StyleLineNameListValue>);
 360
 361   /**
 362    * Reflow and place our children.
 363    * @return the consumed size of all of this grid container's continuations
 364    *         so far including this frame
 365    */
 366   nscoord ReflowChildren(GridReflowInput& aState,
 367                          const LogicalRect& aContentArea,
 368                          const nsSize& aContainerSize,
 369                          ReflowOutput& aDesiredSize, nsReflowStatus& aStatus);
 370
 371   /**
 372    * Helper for GetMinISize / GetPrefISize.
 373    */
 374   nscoord IntrinsicISize(gfxContext* aRenderingContext,
 375                          mozilla::IntrinsicISizeType aConstraint);
 376
 377   nscoord GetBBaseline(BaselineSharingGroup aBaselineGroup) const {
 378     return mBaseline[mozilla::LogicalAxis::Block][aBaselineGroup];
 379   }
 380   nscoord GetIBaseline(BaselineSharingGroup aBaselineGroup) const {
 381     return mBaseline[mozilla::LogicalAxis::Inline][aBaselineGroup];
 382   }
 383
 384   /**
 385    * Calculate this grid container's baselines.
 386    * @param aBaselineSet which baseline(s) to derive from a baseline-group or
 387    * items; a baseline not included is synthesized from the border-box instead.
 388    * @param aFragmentStartTrack is the first track in this fragment in the same
 389    * axis as aMajor.  Pass zero if that's not the axis we're fragmenting in.
 390    * @param aFirstExcludedTrack should be the first track in the next fragment
 391    * or one beyond the final track in the last fragment, in aMajor's axis.
 392    * Pass the number of tracks if that's not the axis we're fragmenting in.
 393    */
 394   enum BaselineSet : uint32_t {
 395     eNone = 0x0,
 396     eFirst = 0x1,
 397     eLast = 0x2,
 398     eBoth = eFirst | eLast,
 399   };
 400   void CalculateBaselines(BaselineSet aBaselineSet,
 401                           mozilla::CSSOrderAwareFrameIterator* aIter,
 402                           const nsTArray<GridItemInfo>* aGridItems,
 403                           const Tracks& aTracks, uint32_t aFragmentStartTrack,
 404                           uint32_t aFirstExcludedTrack, WritingMode aWM,
 405                           const nsSize& aCBPhysicalSize,
 406                           nscoord aCBBorderPaddingStart,
 407                           nscoord aCBBorderPaddingStartEnd, nscoord aCBSize);
 408
 409   /**
 410    * Synthesize a Grid container baseline for aGroup.
 411    */
 412   nscoord SynthesizeBaseline(const FindItemInGridOrderResult& aGridOrderItem,
 413                              LogicalAxis aAxis, BaselineSharingGroup aGroup,
 414                              const nsSize& aCBPhysicalSize, nscoord aCBSize,
 415                              WritingMode aCBWM);
 416   /**
 417    * Find the first item in Grid Order in this fragment.
 418    * https://drafts.csswg.org/css-grid/#grid-order
 419    * @param aFragmentStartTrack is the first track in this fragment in the same
 420    * axis as aMajor.  Pass zero if that's not the axis we're fragmenting in.
 421    */
 422   static FindItemInGridOrderResult FindFirstItemInGridOrder(
 423       mozilla::CSSOrderAwareFrameIterator& aIter,
 424       const nsTArray<GridItemInfo>& aGridItems, LineRange GridArea::*aMajor,
 425       LineRange GridArea::*aMinor, uint32_t aFragmentStartTrack);
 426   /**
 427    * Find the last item in Grid Order in this fragment.
 428    * @param aFragmentStartTrack is the first track in this fragment in the same
 429    * axis as aMajor.  Pass zero if that's not the axis we're fragmenting in.
 430    * @param aFirstExcludedTrack should be the first track in the next fragment
 431    * or one beyond the final track in the last fragment, in aMajor's axis.
 432    * Pass the number of tracks if that's not the axis we're fragmenting in.
 433    */
 434   static FindItemInGridOrderResult FindLastItemInGridOrder(
 435       mozilla::ReverseCSSOrderAwareFrameIterator& aIter,
 436       const nsTArray<GridItemInfo>& aGridItems, LineRange GridArea::*aMajor,
 437       LineRange GridArea::*aMinor, uint32_t aFragmentStartTrack,
 438       uint32_t aFirstExcludedTrack);
 439
 440   /**
 441    * Update our NS_STATE_GRID_IS_COL/ROW_SUBGRID bits and related subgrid state
 442    * on our entire continuation chain based on the current style.
 443    * This is needed because grid-template-columns/rows style changes only
 444    * trigger a reflow so we need to update this dynamically.
 445    */
 446   void UpdateSubgridFrameState();
 447
 448   /**
 449    * Return the NS_STATE_GRID_IS_COL/ROW_SUBGRID and
 450    * NS_STATE_GRID_IS_ROW/COL_MASONRY bits we ought to have.
 451    */
 452   nsFrameState ComputeSelfSubgridMasonryBits() const;
 453
 454  private:
 455   // Helpers for ReflowChildren
 456   struct Fragmentainer {
 457     /**
 458      * The distance from the first grid container fragment's block-axis content
 459      * edge to the fragmentainer end.
 460      */
 461     nscoord mToFragmentainerEnd;
 462     /**
 463      * True if the current fragment is at the start of the fragmentainer.
 464      */
 465     bool mIsTopOfPage;
 466     /**
 467      * Is there a Class C break opportunity at the start content edge?
 468      */
 469     bool mCanBreakAtStart;
 470     /**
 471      * Is there a Class C break opportunity at the end content edge?
 472      */
 473     bool mCanBreakAtEnd;
 474     /**
 475      * Is the grid container's block-size unconstrained?
 476      */
 477     bool mIsAutoBSize;
 478   };
 479
 480   mozilla::Maybe<nsGridContainerFrame::Fragmentainer> GetNearestFragmentainer(
 481       const GridReflowInput& aState) const;
 482
 483   // @return the consumed size of all continuations so far including this frame
 484   nscoord ReflowInFragmentainer(GridReflowInput& aState,
 485                                 const LogicalRect& aContentArea,
 486                                 ReflowOutput& aDesiredSize,
 487                                 nsReflowStatus& aStatus,
 488                                 Fragmentainer& aFragmentainer,
 489                                 const nsSize& aContainerSize);
 490
 491   // Helper for ReflowInFragmentainer
 492   // @return the consumed size of all continuations so far including this frame
 493   nscoord ReflowRowsInFragmentainer(
 494       GridReflowInput& aState, const LogicalRect& aContentArea,
 495       ReflowOutput& aDesiredSize, nsReflowStatus& aStatus,
 496       Fragmentainer& aFragmentainer, const nsSize& aContainerSize,
 497       const nsTArray<const GridItemInfo*>& aItems, uint32_t aStartRow,
 498       uint32_t aEndRow, nscoord aBSize, nscoord aAvailableSize);
 499
 500   // Helper for ReflowChildren / ReflowInFragmentainer
 501   void ReflowInFlowChild(nsIFrame* aChild, const GridItemInfo* aGridItemInfo,
 502                          nsSize aContainerSize,
 503                          const mozilla::Maybe<nscoord>& aStretchBSize,
 504                          const Fragmentainer* aFragmentainer,
 505                          const GridReflowInput& aState,
 506                          const LogicalRect& aContentArea,
 507                          ReflowOutput& aDesiredSize, nsReflowStatus& aStatus);
 508
 509   /**
 510    * Places and reflows items when we have masonry layout.
 511    * It handles unconstrained reflow and also fragmentation when the row axis
 512    * is the masonry axis.  ReflowInFragmentainer handles the case when we're
 513    * fragmenting and our row axis is a grid axis and it handles masonry layout
 514    * in the column axis in that case.
 515    * @return the intrinsic size in the masonry axis
 516    */
 517   nscoord MasonryLayout(GridReflowInput& aState,
 518                         const LogicalRect& aContentArea,
 519                         SizingConstraint aConstraint,
 520                         ReflowOutput& aDesiredSize, nsReflowStatus& aStatus,
 521                         Fragmentainer* aFragmentainer,
 522                         const nsSize& aContainerSize);
 523
 524   // Return the stored UsedTrackSizes, if any.
 525   UsedTrackSizes* GetUsedTrackSizes() const;
 526
 527   // Store the given TrackSizes in aAxis on a UsedTrackSizes frame property.
 528   void StoreUsedTrackSizes(LogicalAxis aAxis,
 529                            const nsTArray<TrackSize>& aSizes);
 530
 531   // The internal implementation for AddImplicitNamedAreas().
 532   void AddImplicitNamedAreasInternal(LineNameList& aNameList,
 533                                      ImplicitNamedAreas*& aAreas);
 534
 535   /**
 536    * Cached values to optimize GetMinISize/GetPrefISize.
 537    */
 538   nscoord mCachedMinISize;
 539   nscoord mCachedPrefISize;
 540
 541   // Our baselines, one per BaselineSharingGroup per axis.
 542   PerLogicalAxis<PerBaseline<nscoord>> mBaseline;
 543
 544  public:
 545   // A cached result for a grid item's block-axis measuring reflow. This
 546   // cache prevents us from doing exponential reflows in cases of deeply
 547   // nested grid frames.
 548   //
 549   // We store the cached value in the grid item's frame property table.
 550   //
 551   // We cache the following as a "key"
 552   //   - The size of the grid area in the item's inline axis
 553   //   - The item's block axis baseline padding
 554   // ...and we cache the following as the "value",
 555   //   - The item's border-box BSize
 556   class CachedBAxisMeasurement {
 557    public:
 558     NS_DECLARE_FRAME_PROPERTY_SMALL_VALUE(Prop, CachedBAxisMeasurement)
 559     CachedBAxisMeasurement(const nsIFrame* aFrame, const LogicalSize& aCBSize,
 560                            const nscoord aBSize)
 561         : mKey(aFrame, aCBSize), mBSize(aBSize) {}
 562
 563     CachedBAxisMeasurement() = default;
 564
 565     bool IsValidFor(const nsIFrame* aFrame, const LogicalSize& aCBSize) const {
 566       if (aFrame->IsSubtreeDirty()) {
 567         return false;
 568       }
 569
 570       if (!CanCacheMeasurement(aFrame, aCBSize)) {
 571         return false;
 572       }
 573
 574       return mKey == Key(aFrame, aCBSize);
 575     }
 576
 577     static bool CanCacheMeasurement(const nsIFrame* aFrame,
 578                                     const LogicalSize& aCBSize) {
 579       return Key::CanHash(aFrame, aCBSize);
 580     }
 581
 582     nscoord BSize() const { return mBSize; }
 583
 584     void Update(const nsIFrame* aFrame, const LogicalSize& aCBSize,
 585                 const nscoord aBSize) {
 586       MOZ_ASSERT(CanCacheMeasurement(aFrame, aCBSize));
 587       mKey.mHashKey = Key::GenerateHash(aFrame, aCBSize);
 588       mBSize = aBSize;
 589     }
 590
 591    private:
 592     struct Key {
 593       // mHashKey is generated by combining these 2 variables together
 594       //   1. The containing block size in the item's inline axis used
 595       //   for measuring reflow
 596       //   2. The item's baseline padding property
 597       uint32_t mHashKey;
 598
 599       Key() = default;
 600
 601       Key(const nsIFrame* aFrame, const LogicalSize& aCBSize) {
 602         MOZ_ASSERT(CanHash(aFrame, aCBSize));
 603         mHashKey = GenerateHash(aFrame, aCBSize);
 604       }
 605
 606       void UpdateHash(const nsIFrame* aFrame, const LogicalSize& aCBSize) {
 607         MOZ_ASSERT(CanHash(aFrame, aCBSize));
 608         mHashKey = GenerateHash(aFrame, aCBSize);
 609       }
 610
 611       static uint32_t GenerateHash(const nsIFrame* aFrame,
 612                                    const LogicalSize& aCBSize) {
 613         MOZ_ASSERT(CanHash(aFrame, aCBSize));
 614
 615         nscoord gridAreaISize = aCBSize.ISize(aFrame->GetWritingMode());
 616         nscoord bBaselinePaddingProperty =
 617             abs(aFrame->GetProperty(nsIFrame::BBaselinePadProperty()));
 618
 619         uint_fast8_t bitsNeededForISize = mozilla::FloorLog2(gridAreaISize) + 1;
 620
 621         return (gridAreaISize << (32 - bitsNeededForISize)) |
 622                bBaselinePaddingProperty;
 623       }
 624
 625       static bool CanHash(const nsIFrame* aFrame, const LogicalSize& aCBSize) {
 626         uint_fast8_t bitsNeededForISize =
 627             mozilla::FloorLog2(aCBSize.ISize(aFrame->GetWritingMode())) + 1;
 628
 629         uint_fast8_t bitsNeededForBBaselinePadding =
 630             mozilla::FloorLog2(
 631                 abs(aFrame->GetProperty(nsIFrame::BBaselinePadProperty()))) +
 632             1;
 633
 634         return bitsNeededForISize + bitsNeededForBBaselinePadding <= 32;
 635       }
 636
 637       bool operator==(const Key& aOther) const {
 638         return mHashKey == aOther.mHashKey;
 639       }
 640     };
 641
 642     Key mKey;
 643     nscoord mBSize;
 644   };
 645
 646   bool CanProvideLineIterator() const final { return true; }
 647   nsILineIterator* GetLineIterator() final { return this; }
 648   int32_t GetNumLines() const final;
 649   bool IsLineIteratorFlowRTL() final;
 650   mozilla::Result<LineInfo, nsresult> GetLine(int32_t aLineNumber) final;
 651   int32_t FindLineContaining(nsIFrame* aFrame, int32_t aStartLine = 0) final;
 652   NS_IMETHOD FindFrameAt(int32_t aLineNumber, nsPoint aPos,
 653                          nsIFrame** aFrameFound, bool* aPosIsBeforeFirstFrame,
 654                          bool* aPosIsAfterLastFrame) final;
 655   NS_IMETHOD CheckLineOrder(int32_t aLine, bool* aIsReordered,
 656                             nsIFrame** aFirstVisual,
 657                             nsIFrame** aLastVisual) final;
 658 };
 659
 660 #endif /* nsGridContainerFrame_h___ */