Adding upstream version 1:115.7.0.upstream/1%115.7.0upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 464 insertions, 0 deletions

diff --git a/layout/generic/nsFloatManager.h b/layout/generic/nsFloatManager.h
new file mode 100644
index 0000000000..b168987988
--- /dev/null
+++ b/layout/generic/nsFloatManager.h
@@ -0,0 +1,464 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* class that manages rules for positioning floats */
+
+#ifndef nsFloatManager_h_
+#define nsFloatManager_h_
+
+#include "mozilla/Attributes.h"
+#include "mozilla/TypedEnumBits.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/WritingModes.h"
+#include "nsCoord.h"
+#include "nsFrameList.h"  // for DEBUG_FRAME_DUMP
+#include "nsIntervalSet.h"
+#include "nsPoint.h"
+#include "nsTArray.h"
+
+class nsIFrame;
+class nsPresContext;
+namespace mozilla {
+struct ReflowInput;
+class PresShell;
+}  // namespace mozilla
+
+enum class nsFlowAreaRectFlags : uint32_t {
+  NoFlags = 0,
+  HasFloats = 1 << 0,
+  MayWiden = 1 << 1,
+  ISizeIsActuallyNegative = 1 << 2,
+};
+MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(nsFlowAreaRectFlags)
+
+/**
+ * The available space for content not occupied by floats is divided
+ * into a sequence of rectangles in the block direction.  However, we
+ * need to know not only the rectangle, but also whether it was reduced
+ * (from the content rectangle) by floats that actually intruded into
+ * the content rectangle. If it has been reduced by floats, then we also
+ * track whether the flow area might widen as the floats narrow in the
+ * block direction.
+ */
+struct nsFlowAreaRect {
+  mozilla::LogicalRect mRect;
+
+  nsFlowAreaRectFlags mAreaFlags;
+
+  nsFlowAreaRect(mozilla::WritingMode aWritingMode, nscoord aICoord,
+                 nscoord aBCoord, nscoord aISize, nscoord aBSize,
+                 nsFlowAreaRectFlags aAreaFlags)
+      : mRect(aWritingMode, aICoord, aBCoord, aISize, aBSize),
+        mAreaFlags(aAreaFlags) {}
+
+  bool HasFloats() const {
+    return (bool)(mAreaFlags & nsFlowAreaRectFlags::HasFloats);
+  }
+  bool MayWiden() const {
+    return (bool)(mAreaFlags & nsFlowAreaRectFlags::MayWiden);
+  }
+  bool ISizeIsActuallyNegative() const {
+    return (bool)(mAreaFlags & nsFlowAreaRectFlags::ISizeIsActuallyNegative);
+  }
+};
+
+#define NS_FLOAT_MANAGER_CACHE_SIZE 64
+
+/**
+ * nsFloatManager is responsible for implementing CSS's rules for
+ * positioning floats. An nsFloatManager object is created during reflow for
+ * any block with NS_BLOCK_FLOAT_MGR. During reflow, the float manager for
+ * the nearest such ancestor block is found in ReflowInput::mFloatManager.
+ *
+ * According to the line-relative mappings in CSS Writing Modes spec [1],
+ * line-right and line-left are calculated with respect to the writing mode
+ * of the containing block of the floats. All the writing modes passed to
+ * nsFloatManager methods should be the containing block's writing mode.
+ *
+ * However, according to the abstract-to-physical mappings table [2], the
+ * 'direction' property of the containing block doesn't affect the
+ * interpretation of line-right and line-left. We actually implement this by
+ * passing in the writing mode of the block formatting context (BFC), i.e.
+ * the of BlockReflowState's writing mode.
+ *
+ * nsFloatManager uses a special logical coordinate space with inline
+ * coordinates on the line-axis and block coordinates on the block-axis
+ * based on the writing mode of the block formatting context. All the
+ * physical types like nsRect, nsPoint, etc. use this coordinate space. See
+ * FloatInfo::mRect for an example.
+ *
+ * [1] https://drafts.csswg.org/css-writing-modes/#line-mappings
+ * [2] https://drafts.csswg.org/css-writing-modes/#logical-to-physical
+ */
+class nsFloatManager {
+ public:
+  explicit nsFloatManager(mozilla::PresShell* aPresShell,
+                          mozilla::WritingMode aWM);
+  ~nsFloatManager();
+
+  void* operator new(size_t aSize) noexcept(true);
+  void operator delete(void* aPtr, size_t aSize);
+
+  static void Shutdown();
+
+  /**
+   * Get float region stored on the frame. (Defaults to mRect if it's
+   * not there.) The float region is the area impacted by this float;
+   * the coordinates are relative to the containing block frame.
+   */
+  static mozilla::LogicalRect GetRegionFor(mozilla::WritingMode aWM,
+                                           nsIFrame* aFloatFrame,
+                                           const nsSize& aContainerSize);
+  /**
+   * Calculate the float region for this frame using aMargin and the
+   * frame's mRect. The region includes the margins around the float,
+   * but doesn't include the relative offsets.
+   * Note that if the frame is or has a continuation, aMargin's top
+   * and/or bottom must be zeroed by the caller.
+   */
+  static mozilla::LogicalRect CalculateRegionFor(
+      mozilla::WritingMode aWM, nsIFrame* aFloatFrame,
+      const mozilla::LogicalMargin& aMargin, const nsSize& aContainerSize);
+  /**
+   * Store the float region on the frame. The region is stored
+   * as a delta against the mRect, so repositioning the frame will
+   * also reposition the float region.
+   */
+  static void StoreRegionFor(mozilla::WritingMode aWM, nsIFrame* aFloat,
+                             const mozilla::LogicalRect& aRegion,
+                             const nsSize& aContainerSize);
+
+  // Structure that stores the current state of a float manager for
+  // Save/Restore purposes.
+  struct SavedState {
+    explicit SavedState()
+        : mFloatInfoCount(0),
+          mLineLeft(0),
+          mBlockStart(0),
+          mPushedLeftFloatPastBreak(false),
+          mPushedRightFloatPastBreak(false),
+          mSplitLeftFloatAcrossBreak(false),
+          mSplitRightFloatAcrossBreak(false) {}
+
+   private:
+    uint32_t mFloatInfoCount;
+    nscoord mLineLeft, mBlockStart;
+    bool mPushedLeftFloatPastBreak;
+    bool mPushedRightFloatPastBreak;
+    bool mSplitLeftFloatAcrossBreak;
+    bool mSplitRightFloatAcrossBreak;
+
+    friend class nsFloatManager;
+  };
+
+  /**
+   * Translate the current origin by the specified offsets. This
+   * creates a new local coordinate space relative to the current
+   * coordinate space.
+   */
+  void Translate(nscoord aLineLeft, nscoord aBlockStart) {
+    mLineLeft += aLineLeft;
+    mBlockStart += aBlockStart;
+  }
+
+  /**
+   * Returns the current translation from local coordinate space to
+   * world coordinate space. This represents the accumulated calls to
+   * Translate().
+   */
+  void GetTranslation(nscoord& aLineLeft, nscoord& aBlockStart) const {
+    aLineLeft = mLineLeft;
+    aBlockStart = mBlockStart;
+  }
+
+  /**
+   * Get information about the area available to content that flows
+   * around floats.  Two different types of space can be requested:
+   *   BandFromPoint: returns the band containing block-dir coordinate
+   *     |aBCoord| (though actually with the top truncated to begin at
+   *     aBCoord), but up to at most |aBSize| (which may be nscoord_MAX).
+   *     This will return the tallest rectangle whose block start is
+   *     |aBCoord| and in which there are no changes in what floats are
+   *     on the sides of that rectangle, but will limit the block size
+   *     of the rectangle to |aBSize|.  The inline start and end edges
+   *     of the rectangle give the area available for line boxes in that
+   *     space. The inline size of this resulting rectangle will not be
+   *     negative.
+   *   WidthWithinHeight: This returns a rectangle whose block start
+   *     is aBCoord and whose block size is exactly aBSize.  Its inline
+   *     start and end edges give the corresponding edges of the space
+   *     that can be used for line boxes *throughout* that space.  (It
+   *     is possible that more inline space could be used in part of the
+   *     space if a float begins or ends in it.)  The inline size of the
+   *     resulting rectangle can be negative.
+   *
+   * ShapeType can be used to request two different types of flow areas.
+   * (This is the float area defined in CSS Shapes Module Level 1 §1.4):
+   *    Margin: uses the float element's margin-box to request the flow area.
+   *    ShapeOutside: uses the float element's shape-outside value to request
+   *      the float area.
+   *
+   * @param aBCoord [in] block-dir coordinate for block start of available space
+   *          desired, which are positioned relative to the current translation.
+   * @param aBSize [in] see above
+   * @param aContentArea [in] an nsRect representing the content area
+   * @param aState [in] If null, use the current state, otherwise, do
+   *                    computation based only on floats present in the given
+   *                    saved state.
+   * @return An nsFlowAreaRect whose:
+   *           mRect is the resulting rectangle for line boxes.  It will not
+   *             extend beyond aContentArea's inline bounds, but may be
+   *             narrower when floats are present.
+   *           mHasFloats is whether there are floats at the sides of the
+   *             return value including those that do not reduce the line box
+   *             inline size at all (because they are entirely in the margins)
+   */
+  enum class BandInfoType { BandFromPoint, WidthWithinHeight };
+  enum class ShapeType { Margin, ShapeOutside };
+  nsFlowAreaRect GetFlowArea(mozilla::WritingMode aWM, nscoord aBCoord,
+                             nscoord aBSize, BandInfoType aBandInfoType,
+                             ShapeType aShapeType,
+                             mozilla::LogicalRect aContentArea,
+                             SavedState* aState,
+                             const nsSize& aContainerSize) const;
+
+  /**
+   * Add a float that comes after all floats previously added.  Its
+   * block start must be even with or below the top of all previous
+   * floats.
+   *
+   * aMarginRect is relative to the current translation.  The caller
+   * must ensure aMarginRect.height >= 0 and aMarginRect.width >= 0.
+   */
+  void AddFloat(nsIFrame* aFloatFrame, const mozilla::LogicalRect& aMarginRect,
+                mozilla::WritingMode aWM, const nsSize& aContainerSize);
+
+  /**
+   * Notify that we tried to place a float that could not fit at all and
+   * had to be pushed to the next page/column?  (If so, we can't place
+   * any more floats in this page/column because of the rule that the
+   * top of a float cannot be above the top of an earlier float.  It
+   * also means that any clear needs to continue to the next column.)
+   */
+  void SetPushedLeftFloatPastBreak() { mPushedLeftFloatPastBreak = true; }
+  void SetPushedRightFloatPastBreak() { mPushedRightFloatPastBreak = true; }
+
+  /**
+   * Notify that we split a float, with part of it needing to be pushed
+   * to the next page/column.  (This means that any 'clear' needs to
+   * continue to the next page/column.)
+   */
+  void SetSplitLeftFloatAcrossBreak() { mSplitLeftFloatAcrossBreak = true; }
+  void SetSplitRightFloatAcrossBreak() { mSplitRightFloatAcrossBreak = true; }
+
+  /**
+   * Remove the regions associated with this floating frame and its
+   * next-sibling list.  Some of the frames may never have been added;
+   * we just skip those. This is not fully general; it only works as
+   * long as the N frames to be removed are the last N frames to have
+   * been added; if there's a frame in the middle of them that should
+   * not be removed, YOU LOSE.
+   */
+  nsresult RemoveTrailingRegions(nsIFrame* aFrameList);
+
+  bool HasAnyFloats() const { return !mFloats.IsEmpty(); }
+
+  /**
+   * Methods for dealing with the propagation of float damage during
+   * reflow.
+   */
+  bool HasFloatDamage() const { return !mFloatDamage.IsEmpty(); }
+
+  void IncludeInDamage(nscoord aIntervalBegin, nscoord aIntervalEnd) {
+    mFloatDamage.IncludeInterval(aIntervalBegin + mBlockStart,
+                                 aIntervalEnd + mBlockStart);
+  }
+
+  bool IntersectsDamage(nscoord aIntervalBegin, nscoord aIntervalEnd) const {
+    return mFloatDamage.Intersects(aIntervalBegin + mBlockStart,
+                                   aIntervalEnd + mBlockStart);
+  }
+
+  /**
+   * Saves the current state of the float manager into aState.
+   */
+  void PushState(SavedState* aState);
+
+  /**
+   * Restores the float manager to the saved state.
+   *
+   * These states must be managed using stack discipline. PopState can only
+   * be used after PushState has been used to save the state, and it can only
+   * be used once --- although it can be omitted; saved states can be ignored.
+   * States must be popped in the reverse order they were pushed.  A
+   * call to PopState invalidates any saved states Pushed after the
+   * state passed to PopState was pushed.
+   */
+  void PopState(SavedState* aState);
+
+  /**
+   * Get the block start of the last float placed into the float
+   * manager, to enforce the rule that a float can't be above an earlier
+   * float. Returns the minimum nscoord value if there are no floats.
+   *
+   * The result is relative to the current translation.
+   */
+  nscoord LowestFloatBStart() const;
+
+  /**
+   * Return the coordinate of the lowest float matching aClearType in
+   * this float manager. Returns aBCoord if there are no matching
+   * floats.
+   *
+   * Both aBCoord and the result are relative to the current translation.
+   */
+  nscoord ClearFloats(nscoord aBCoord, mozilla::StyleClear aClearType) const;
+
+  /**
+   * Checks if clear would pass into the floats' BFC's next-in-flow,
+   * i.e. whether floats affecting this clear have continuations.
+   */
+  bool ClearContinues(mozilla::StyleClear aClearType) const;
+
+  void AssertStateMatches(SavedState* aState) const {
+    NS_ASSERTION(
+        aState->mLineLeft == mLineLeft && aState->mBlockStart == mBlockStart &&
+            aState->mPushedLeftFloatPastBreak == mPushedLeftFloatPastBreak &&
+            aState->mPushedRightFloatPastBreak == mPushedRightFloatPastBreak &&
+            aState->mSplitLeftFloatAcrossBreak == mSplitLeftFloatAcrossBreak &&
+            aState->mSplitRightFloatAcrossBreak ==
+                mSplitRightFloatAcrossBreak &&
+            aState->mFloatInfoCount == mFloats.Length(),
+        "float manager state should match saved state");
+  }
+
+#ifdef DEBUG_FRAME_DUMP
+  /**
+   * Dump the state of the float manager out to a file.
+   */
+  nsresult List(FILE* out) const;
+#endif
+
+ private:
+  class ShapeInfo;
+  class RoundedBoxShapeInfo;
+  class EllipseShapeInfo;
+  class PolygonShapeInfo;
+  class ImageShapeInfo;
+
+  struct FloatInfo {
+    nsIFrame* const mFrame;
+    // The lowest block-ends of left/right floats up to and including
+    // this one.
+    nscoord mLeftBEnd, mRightBEnd;
+
+    FloatInfo(nsIFrame* aFrame, nscoord aLineLeft, nscoord aBlockStart,
+              const mozilla::LogicalRect& aMarginRect, mozilla::WritingMode aWM,
+              const nsSize& aContainerSize);
+
+    nscoord LineLeft() const { return mRect.x; }
+    nscoord LineRight() const { return mRect.XMost(); }
+    nscoord ISize() const { return mRect.width; }
+    nscoord BStart() const { return mRect.y; }
+    nscoord BEnd() const { return mRect.YMost(); }
+    nscoord BSize() const { return mRect.height; }
+    bool IsEmpty() const { return mRect.IsEmpty(); }
+
+    // aBStart and aBEnd are the starting and ending coordinate of a band.
+    // LineLeft() and LineRight() return the innermost line-left extent and
+    // line-right extent within the given band, respectively.
+    nscoord LineLeft(ShapeType aShapeType, const nscoord aBStart,
+                     const nscoord aBEnd) const;
+    nscoord LineRight(ShapeType aShapeType, const nscoord aBStart,
+                      const nscoord aBEnd) const;
+    nscoord BStart(ShapeType aShapeType) const;
+    nscoord BEnd(ShapeType aShapeType) const;
+    bool IsEmpty(ShapeType aShapeType) const;
+    bool MayNarrowInBlockDirection(ShapeType aShapeType) const;
+
+#ifdef NS_BUILD_REFCNT_LOGGING
+    FloatInfo(FloatInfo&& aOther);
+    ~FloatInfo();
+#endif
+
+    // NB! This is really a logical rect in a writing mode suitable for
+    // placing floats, which is not necessarily the actual writing mode
+    // either of the block which created the float manager or the block
+    // that is calling the float manager. The inline coordinates are in
+    // the line-relative axis of the float manager and its block
+    // coordinates are in the float manager's block direction.
+    nsRect mRect;
+    // Pointer to a concrete subclass of ShapeInfo or null, which means that
+    // there is no shape-outside.
+    mozilla::UniquePtr<ShapeInfo> mShapeInfo;
+  };
+
+#ifdef DEBUG
+  // Store the writing mode from the block frame which establishes the block
+  // formatting context (BFC) when the nsFloatManager is created.
+  mozilla::WritingMode mWritingMode;
+#endif
+
+  // Translation from local to global coordinate space.
+  nscoord mLineLeft, mBlockStart;
+  // We use 11 here in order to fill up the jemalloc allocatoed chunk nicely,
+  // see https://bugzilla.mozilla.org/show_bug.cgi?id=1362876#c6.
+  AutoTArray<FloatInfo, 11> mFloats;
+  nsIntervalSet mFloatDamage;
+
+  // Did we try to place a float that could not fit at all and had to be
+  // pushed to the next page/column?  If so, we can't place any more
+  // floats in this page/column because of the rule that the top of a
+  // float cannot be above the top of an earlier float.  And we also
+  // need to apply this information to 'clear', and thus need to
+  // separate left and right floats.
+  bool mPushedLeftFloatPastBreak;
+  bool mPushedRightFloatPastBreak;
+
+  // Did we split a float, with part of it needing to be pushed to the
+  // next page/column.  This means that any 'clear' needs to continue to
+  // the next page/column.
+  bool mSplitLeftFloatAcrossBreak;
+  bool mSplitRightFloatAcrossBreak;
+
+  static int32_t sCachedFloatManagerCount;
+  static void* sCachedFloatManagers[NS_FLOAT_MANAGER_CACHE_SIZE];
+
+  nsFloatManager(const nsFloatManager&) = delete;
+  void operator=(const nsFloatManager&) = delete;
+};
+
+/**
+ * A helper class to manage maintenance of the float manager during
+ * nsBlockFrame::Reflow. It automatically restores the old float
+ * manager in the reflow input when the object goes out of scope.
+ */
+class nsAutoFloatManager {
+  using ReflowInput = mozilla::ReflowInput;
+
+ public:
+  explicit nsAutoFloatManager(ReflowInput& aReflowInput)
+      : mReflowInput(aReflowInput), mOld(nullptr) {}
+
+  ~nsAutoFloatManager();
+
+  /**
+   * Create a new float manager for the specified frame. This will
+   * `remember' the old float manager, and install the new float
+   * manager in the reflow input.
+   */
+  void CreateFloatManager(nsPresContext* aPresContext);
+
+ protected:
+  ReflowInput& mReflowInput;
+  mozilla::UniquePtr<nsFloatManager> mNew;
+
+  // A non-owning pointer, which points to the object owned by
+  // nsAutoFloatManager::mNew.
+  nsFloatManager* mOld;
+};
+
+#endif /* !defined(nsFloatManager_h_) */