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