The Tor Browser: layout/generic/nsHTMLReflowState.cpp@6474c204b198 (annotated)

layout/generic/nsHTMLReflowState.cpp@6474c204b198 (annotated)

layout/generic/nsHTMLReflowState.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* 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/. */
 /* struct containing the input to nsIFrame::Reflow */
 #include "nsHTMLReflowState.h"
 #include "nsStyleConsts.h"
 #include "nsCSSAnonBoxes.h"
 #include "nsFrame.h"
 #include "nsIContent.h"
 #include "nsGkAtoms.h"
 #include "nsPresContext.h"
 #include "nsIPresShell.h"
 #include "nsFontMetrics.h"
 #include "nsBlockFrame.h"
 #include "nsLineBox.h"
 #include "nsFlexContainerFrame.h"
 #include "nsImageFrame.h"
 #include "nsTableFrame.h"
 #include "nsTableCellFrame.h"
 #include "nsIPercentHeightObserver.h"
 #include "nsLayoutUtils.h"
 #include "mozilla/Preferences.h"
 #include "nsFontInflationData.h"
 #include "StickyScrollContainer.h"
 #include "nsIFrameInlines.h"
 #include <algorithm>
 #include "mozilla/dom/HTMLInputElement.h"
 #ifdef DEBUG
 #undef NOISY_VERTICAL_ALIGN
 #else
 #undef NOISY_VERTICAL_ALIGN
 #endif
 using namespace mozilla;
 using namespace mozilla::css;
 using namespace mozilla::dom;
 using namespace mozilla::layout;
 enum eNormalLineHeightControl {
   eUninitialized = -1,
   eNoExternalLeading = 0,   // does not include external leading
   eIncludeExternalLeading,  // use whatever value font vendor provides
   eCompensateLeading        // compensate leading if leading provided by font vendor is not enough
 };
 static eNormalLineHeightControl sNormalLineHeightControl = eUninitialized;
 // Initialize a <b>root</b> reflow state with a rendering context to
 // use for measuring things.
 nsHTMLReflowState::nsHTMLReflowState(nsPresContext*       aPresContext,
                                      nsIFrame*            aFrame,
                                      nsRenderingContext*  aRenderingContext,
                                      const nsSize&        aAvailableSpace,
                                      uint32_t             aFlags)
   : nsCSSOffsetState(aFrame, aRenderingContext)
   , mBlockDelta(0)
   , mReflowDepth(0)
 {
   NS_PRECONDITION(aRenderingContext, "no rendering context");
   MOZ_ASSERT(aPresContext, "no pres context");
   MOZ_ASSERT(aFrame, "no frame");
   MOZ_ASSERT(aPresContext == aFrame->PresContext(), "wrong pres context");
   parentReflowState = nullptr;
   AvailableWidth() = aAvailableSpace.width;
   AvailableHeight() = aAvailableSpace.height;
   mFloatManager = nullptr;
   mLineLayout = nullptr;
   memset(&mFlags, 0, sizeof(mFlags));
   mDiscoveredClearance = nullptr;
   mPercentHeightObserver = nullptr;
   if (aFlags & DUMMY_PARENT_REFLOW_STATE) {
     mFlags.mDummyParentReflowState = true;
   }
   if (!(aFlags & CALLER_WILL_INIT)) {
     Init(aPresContext);
   }
 }
 static bool CheckNextInFlowParenthood(nsIFrame* aFrame, nsIFrame* aParent)
 {
   nsIFrame* frameNext = aFrame->GetNextInFlow();
   nsIFrame* parentNext = aParent->GetNextInFlow();
   return frameNext && parentNext && frameNext->GetParent() == parentNext;
 }
 /**
  * Adjusts the margin for a list (ol, ul), if necessary, depending on
  * font inflation settings. Unfortunately, because bullets from a list are
  * placed in the margin area, we only have ~40px in which to place the
  * bullets. When they are inflated, however, this causes problems, since
  * the text takes up more space than is available in the margin.
  *
  * This method will return a small amount (in app units) by which the
  * margin can be adjusted, so that the space is available for list
  * bullets to be rendered with font inflation enabled.
  */
 static  nscoord
 FontSizeInflationListMarginAdjustment(const nsIFrame* aFrame)
 {
   float inflation = nsLayoutUtils::FontSizeInflationFor(aFrame);
   if (aFrame->IsFrameOfType(nsIFrame::eBlockFrame)) {
     const nsBlockFrame* blockFrame = static_cast<const nsBlockFrame*>(aFrame);
     const nsStyleList* styleList = aFrame->StyleList();
     // We only want to adjust the margins if we're dealing with an ordered
     // list.
     if (inflation > 1.0f &&
         blockFrame->HasBullet() &&
         styleList->mListStyleType != NS_STYLE_LIST_STYLE_NONE &&
         styleList->mListStyleType != NS_STYLE_LIST_STYLE_DISC &&
         styleList->mListStyleType != NS_STYLE_LIST_STYLE_CIRCLE &&
         styleList->mListStyleType != NS_STYLE_LIST_STYLE_SQUARE &&
         inflation > 1.0f) {
       // The HTML spec states that the default padding for ordered lists begins
       // at 40px, indicating that we have 40px of space to place a bullet. When
       // performing font inflation calculations, we add space equivalent to this,
       // but simply inflated at the same amount as the text, in app units.
       return nsPresContext::CSSPixelsToAppUnits(40) * (inflation - 1);
     }
   }
   return 0;
 }
 // NOTE: If we ever want to use nsCSSOffsetState for a flex item or a grid
 // item, we need to make it take the containing-block height as well as the
 // width, since flex items and grid items resolve vertical percent margins
 // and padding against the containing-block height, rather than its width.
 nsCSSOffsetState::nsCSSOffsetState(nsIFrame *aFrame,
                                    nsRenderingContext *aRenderingContext,
                                    nscoord aContainingBlockWidth)
   : frame(aFrame)
   , rendContext(aRenderingContext)
   , mWritingMode(aFrame->GetWritingMode())
 {
   MOZ_ASSERT(!aFrame->IsFlexItem(),
              "We're about to resolve vertical percent margin & padding "
              "values against CB width, which is incorrect for flex items");
   InitOffsets(aContainingBlockWidth, aContainingBlockWidth, frame->GetType());
 }
 // Initialize a reflow state for a child frame's reflow. Some state
 // is copied from the parent reflow state; the remaining state is
 // computed.
 nsHTMLReflowState::nsHTMLReflowState(nsPresContext*           aPresContext,
                                      const nsHTMLReflowState& aParentReflowState,
                                      nsIFrame*                aFrame,
                                      const nsSize&            aAvailableSpace,
                                      nscoord                  aContainingBlockWidth,
                                      nscoord                  aContainingBlockHeight,
                                      uint32_t                 aFlags)
   : nsCSSOffsetState(aFrame, aParentReflowState.rendContext)
   , mBlockDelta(0)
   , mReflowDepth(aParentReflowState.mReflowDepth + 1)
   , mFlags(aParentReflowState.mFlags)
 {
   MOZ_ASSERT(aPresContext, "no pres context");
   MOZ_ASSERT(aFrame, "no frame");
   MOZ_ASSERT(aPresContext == aFrame->PresContext(), "wrong pres context");
   NS_PRECONDITION((aContainingBlockWidth == -1) ==
                     (aContainingBlockHeight == -1),
                   "cb width and height should only be non-default together");
   NS_PRECONDITION(!mFlags.mSpecialHeightReflow ||
                   !NS_SUBTREE_DIRTY(aFrame),
                   "frame should be clean when getting special height reflow");
   parentReflowState = &aParentReflowState;
   // If the parent is dirty, then the child is as well.
   // XXX Are the other cases where the parent reflows a child a second
   // time, as a resize?
   if (!mFlags.mSpecialHeightReflow)
     frame->AddStateBits(parentReflowState->frame->GetStateBits() &
                         NS_FRAME_IS_DIRTY);
   AvailableWidth() = aAvailableSpace.width;
   AvailableHeight() = aAvailableSpace.height;
   mFloatManager = aParentReflowState.mFloatManager;
   if (frame->IsFrameOfType(nsIFrame::eLineParticipant))
     mLineLayout = aParentReflowState.mLineLayout;
   else
     mLineLayout = nullptr;
   // Note: mFlags was initialized as a copy of aParentReflowState.mFlags up in
   // this constructor's init list, so the only flags that we need to explicitly
   // initialize here are those that may need a value other than our parent's.
   mFlags.mNextInFlowUntouched = aParentReflowState.mFlags.mNextInFlowUntouched &&
     CheckNextInFlowParenthood(aFrame, aParentReflowState.frame);
   mFlags.mAssumingHScrollbar = mFlags.mAssumingVScrollbar = false;
   mFlags.mHasClearance = false;
   mFlags.mIsColumnBalancing = false;
   mFlags.mIsFlexContainerMeasuringHeight = false;
   mFlags.mDummyParentReflowState = false;
   mDiscoveredClearance = nullptr;
   mPercentHeightObserver = (aParentReflowState.mPercentHeightObserver &&
                             aParentReflowState.mPercentHeightObserver->NeedsToObserve(*this))
                            ? aParentReflowState.mPercentHeightObserver : nullptr;
   if (aFlags & DUMMY_PARENT_REFLOW_STATE) {
     mFlags.mDummyParentReflowState = true;
   }
   if (!(aFlags & CALLER_WILL_INIT)) {
     Init(aPresContext, aContainingBlockWidth, aContainingBlockHeight);
   }
 }
 inline nscoord
 nsCSSOffsetState::ComputeWidthValue(nscoord aContainingBlockWidth,
                                     nscoord aContentEdgeToBoxSizing,
                                     nscoord aBoxSizingToMarginEdge,
                                     const nsStyleCoord& aCoord)
 {
   return nsLayoutUtils::ComputeWidthValue(rendContext, frame,
                                           aContainingBlockWidth,
                                           aContentEdgeToBoxSizing,
                                           aBoxSizingToMarginEdge,
                                           aCoord);
 }
 nscoord
 nsCSSOffsetState::ComputeWidthValue(nscoord aContainingBlockWidth,
                                     uint8_t aBoxSizing,
                                     const nsStyleCoord& aCoord)
 {
   nscoord inside = 0, outside = ComputedPhysicalBorderPadding().LeftRight() +
                                 ComputedPhysicalMargin().LeftRight();
   switch (aBoxSizing) {
     case NS_STYLE_BOX_SIZING_BORDER:
       inside = ComputedPhysicalBorderPadding().LeftRight();
       break;
     case NS_STYLE_BOX_SIZING_PADDING:
       inside = ComputedPhysicalPadding().LeftRight();
       break;
   }
   outside -= inside;
   return ComputeWidthValue(aContainingBlockWidth, inside,
                            outside, aCoord);
 }
 nscoord
 nsCSSOffsetState::ComputeHeightValue(nscoord aContainingBlockHeight,
                                      uint8_t aBoxSizing,
                                      const nsStyleCoord& aCoord)
 {
   nscoord inside = 0;
   switch (aBoxSizing) {
     case NS_STYLE_BOX_SIZING_BORDER:
       inside = ComputedPhysicalBorderPadding().TopBottom();
       break;
     case NS_STYLE_BOX_SIZING_PADDING:
       inside = ComputedPhysicalPadding().TopBottom();
       break;
   }
   return nsLayoutUtils::ComputeHeightValue(aContainingBlockHeight,
                                            inside, aCoord);
 }
 void
 nsHTMLReflowState::SetComputedWidth(nscoord aComputedWidth)
 {
   NS_ASSERTION(frame, "Must have a frame!");
   // It'd be nice to assert that |frame| is not in reflow, but this fails for
   // two reasons:
   //
   // 1) Viewport frames reset the computed width on a copy of their reflow
   //    state when reflowing fixed-pos kids.  In that case we actually don't
   //    want to mess with the resize flags, because comparing the frame's rect
   //    to the munged computed width is pointless.
   // 2) nsFrame::BoxReflow creates a reflow state for its parent.  This reflow
   //    state is not used to reflow the parent, but just as a parent for the
   //    frame's own reflow state.  So given a nsBoxFrame inside some non-XUL
   //    (like a text control, for example), we'll end up creating a reflow
   //    state for the parent while the parent is reflowing.
   NS_PRECONDITION(aComputedWidth >= 0, "Invalid computed width");
   if (ComputedWidth() != aComputedWidth) {
     ComputedWidth() = aComputedWidth;
     nsIAtom* frameType = frame->GetType();
     if (frameType != nsGkAtoms::viewportFrame) { // Or check GetParent()?
       InitResizeFlags(frame->PresContext(), frameType);
     }
   }
 }
 void
 nsHTMLReflowState::SetComputedHeight(nscoord aComputedHeight)
 {
   NS_ASSERTION(frame, "Must have a frame!");
   // It'd be nice to assert that |frame| is not in reflow, but this fails
   // because:
   //
   //    nsFrame::BoxReflow creates a reflow state for its parent.  This reflow
   //    state is not used to reflow the parent, but just as a parent for the
   //    frame's own reflow state.  So given a nsBoxFrame inside some non-XUL
   //    (like a text control, for example), we'll end up creating a reflow
   //    state for the parent while the parent is reflowing.
   NS_PRECONDITION(aComputedHeight >= 0, "Invalid computed height");
   if (ComputedHeight() != aComputedHeight) {
     ComputedHeight() = aComputedHeight;
     InitResizeFlags(frame->PresContext(), frame->GetType());
   }
 }
 void
 nsHTMLReflowState::Init(nsPresContext* aPresContext,
                         nscoord         aContainingBlockWidth,
                         nscoord         aContainingBlockHeight,
                         const nsMargin* aBorder,
                         const nsMargin* aPadding)
 {
   NS_WARN_IF_FALSE(AvailableWidth() != NS_UNCONSTRAINEDSIZE,
                    "have unconstrained width; this should only result from "
                    "very large sizes, not attempts at intrinsic width "
                    "calculation");
   mStylePosition = frame->StylePosition();
   mStyleDisplay = frame->StyleDisplay();
   mStyleVisibility = frame->StyleVisibility();
   mStyleBorder = frame->StyleBorder();
   mStyleMargin = frame->StyleMargin();
   mStylePadding = frame->StylePadding();
   mStyleText = frame->StyleText();
   nsIAtom* type = frame->GetType();
   InitFrameType(type);
   InitCBReflowState();
   InitConstraints(aPresContext, aContainingBlockWidth, aContainingBlockHeight,
                   aBorder, aPadding, type);
   InitResizeFlags(aPresContext, type);
   nsIFrame *parent = frame->GetParent();
   if (parent &&
       (parent->GetStateBits() & NS_FRAME_IN_CONSTRAINED_HEIGHT) &&
       !(parent->GetType() == nsGkAtoms::scrollFrame &&
         parent->StyleDisplay()->mOverflowY != NS_STYLE_OVERFLOW_HIDDEN)) {
     frame->AddStateBits(NS_FRAME_IN_CONSTRAINED_HEIGHT);
   } else if (type == nsGkAtoms::svgForeignObjectFrame) {
     // An SVG foreignObject frame is inherently constrained height.
     frame->AddStateBits(NS_FRAME_IN_CONSTRAINED_HEIGHT);
   } else if ((mStylePosition->mHeight.GetUnit() != eStyleUnit_Auto ||
               mStylePosition->mMaxHeight.GetUnit() != eStyleUnit_None) &&
               // Don't set NS_FRAME_IN_CONSTRAINED_HEIGHT on body or html
               // elements.
              (frame->GetContent() &&
             !(frame->GetContent()->IsHTML(nsGkAtoms::body) ||
               frame->GetContent()->IsHTML(nsGkAtoms::html)))) {
     // If our height was specified as a percentage, then this could
     // actually resolve to 'auto', based on:
     // http://www.w3.org/TR/CSS21/visudet.html#the-height-property
     nsIFrame* containingBlk = frame;
     while (containingBlk) {
       const nsStylePosition* stylePos = containingBlk->StylePosition();
       if ((stylePos->mHeight.IsCoordPercentCalcUnit() &&
            !stylePos->mHeight.HasPercent()) ||
           (stylePos->mMaxHeight.IsCoordPercentCalcUnit() &&
            !stylePos->mMaxHeight.HasPercent())) {
         frame->AddStateBits(NS_FRAME_IN_CONSTRAINED_HEIGHT);
         break;
       } else if ((stylePos->mHeight.IsCoordPercentCalcUnit() &&
                   stylePos->mHeight.HasPercent()) ||
                  (stylePos->mMaxHeight.IsCoordPercentCalcUnit() &&
                   stylePos->mMaxHeight.HasPercent())) {
         if (!(containingBlk = containingBlk->GetContainingBlock())) {
           // If we've reached the top of the tree, then we don't have
           // a constrained height.
           frame->RemoveStateBits(NS_FRAME_IN_CONSTRAINED_HEIGHT);
           break;
         }
         continue;
       } else {
         frame->RemoveStateBits(NS_FRAME_IN_CONSTRAINED_HEIGHT);
         break;
       }
     }
   } else {
     frame->RemoveStateBits(NS_FRAME_IN_CONSTRAINED_HEIGHT);
   }
   NS_WARN_IF_FALSE((mFrameType == NS_CSS_FRAME_TYPE_INLINE &&
                     !frame->IsFrameOfType(nsIFrame::eReplaced)) ||
                    type == nsGkAtoms::textFrame ||
                    ComputedWidth() != NS_UNCONSTRAINEDSIZE,
                    "have unconstrained width; this should only result from "
                    "very large sizes, not attempts at intrinsic width "
                    "calculation");
 }
 void nsHTMLReflowState::InitCBReflowState()
 {
   if (!parentReflowState) {
     mCBReflowState = nullptr;
     return;
   }
   if (parentReflowState->frame == frame->GetContainingBlock()) {
     // Inner table frames need to use the containing block of the outer
     // table frame.
     if (frame->GetType() == nsGkAtoms::tableFrame) {
       mCBReflowState = parentReflowState->mCBReflowState;
     } else {
       mCBReflowState = parentReflowState;
     }
   } else {
     mCBReflowState = parentReflowState->mCBReflowState;
   }
 }
 /* Check whether CalcQuirkContainingBlockHeight would stop on the
  * given reflow state, using its block as a height.  (essentially
  * returns false for any case in which CalcQuirkContainingBlockHeight
  * has a "continue" in its main loop.)
  *
  * XXX Maybe refactor CalcQuirkContainingBlockHeight so it uses
  * this function as well
  */
 static bool
 IsQuirkContainingBlockHeight(const nsHTMLReflowState* rs, nsIAtom* aFrameType)
 {
   if (nsGkAtoms::blockFrame == aFrameType ||
 #ifdef MOZ_XUL
       nsGkAtoms::XULLabelFrame == aFrameType ||
 #endif
       nsGkAtoms::scrollFrame == aFrameType) {
     // Note: This next condition could change due to a style change,
     // but that would cause a style reflow anyway, which means we're ok.
     if (NS_AUTOHEIGHT == rs->ComputedHeight()) {
       if (!rs->frame->IsAbsolutelyPositioned()) {
         return false;
       }
     }
   }
   return true;
 }
 void
 nsHTMLReflowState::InitResizeFlags(nsPresContext* aPresContext, nsIAtom* aFrameType)
 {
   bool isHResize = (frame->GetSize().width !=
                      ComputedWidth() + ComputedPhysicalBorderPadding().LeftRight()) ||
                      aPresContext->PresShell()->IsReflowOnZoomPending();
   if ((frame->GetStateBits() & NS_FRAME_FONT_INFLATION_FLOW_ROOT) &&
       nsLayoutUtils::FontSizeInflationEnabled(aPresContext)) {
     // Create our font inflation data if we don't have it already, and
     // give it our current width information.
     bool dirty = nsFontInflationData::UpdateFontInflationDataWidthFor(*this) &&
                  // Avoid running this at the box-to-block interface
                  // (where we shouldn't be inflating anyway, and where
                  // reflow state construction is probably to construct a
                  // dummy parent reflow state anyway).
                  !mFlags.mDummyParentReflowState;
     if (dirty || (!frame->GetParent() && isHResize)) {
       // When font size inflation is enabled, a change in either:
       //  * the effective width of a font inflation flow root
       //  * the width of the frame
       // needs to cause a dirty reflow since they change the font size
       // inflation calculations, which in turn change the size of text,
       // line-heights, etc.  This is relatively similar to a classic
       // case of style change reflow, except that because inflation
       // doesn't affect the intrinsic sizing codepath, there's no need
       // to invalidate intrinsic sizes.
       //
       // Note that this makes horizontal resizing a good bit more
       // expensive.  However, font size inflation is targeted at a set of
       // devices (zoom-and-pan devices) where the main use case for
       // horizontal resizing needing to be efficient (window resizing) is
       // not present.  It does still increase the cost of dynamic changes
       // caused by script where a style or content change in one place
       // causes a resize in another (e.g., rebalancing a table).
       // FIXME: This isn't so great for the cases where
       // nsHTMLReflowState::SetComputedWidth is called, if the first time
       // we go through InitResizeFlags we set mHResize to true, and then
       // the second time we'd set it to false even without the
       // NS_FRAME_IS_DIRTY bit already set.
       if (frame->GetType() == nsGkAtoms::svgForeignObjectFrame) {
         // Foreign object frames use dirty bits in a special way.
         frame->AddStateBits(NS_FRAME_HAS_DIRTY_CHILDREN);
         nsIFrame *kid = frame->GetFirstPrincipalChild();
         if (kid) {
           kid->AddStateBits(NS_FRAME_IS_DIRTY);
         }
       } else {
         frame->AddStateBits(NS_FRAME_IS_DIRTY);
       }
       // Mark intrinsic widths on all descendants dirty.  We need to do
       // this (1) since we're changing the size of text and need to
       // clear text runs on text frames and (2) since we actually are
       // changing some intrinsic widths, but only those that live inside
       // of containers.
       // It makes sense to do this for descendants but not ancestors
       // (which is unusual) because we're only changing the unusual
       // inflation-dependent intrinsic widths (i.e., ones computed with
       // nsPresContext::mInflationDisabledForShrinkWrap set to false),
       // which should never affect anything outside of their inflation
       // flow root (or, for that matter, even their inflation
       // container).
       // This is also different from what PresShell::FrameNeedsReflow
       // does because it doesn't go through placeholders.  It doesn't
       // need to because we're actually doing something that cares about
       // frame tree geometry (the width on an ancestor) rather than
       // style.
       nsAutoTArray<nsIFrame*, 32> stack;
       stack.AppendElement(frame);
       do {
         nsIFrame *f = stack.ElementAt(stack.Length() - 1);
         stack.RemoveElementAt(stack.Length() - 1);
         nsIFrame::ChildListIterator lists(f);
         for (; !lists.IsDone(); lists.Next()) {
           nsFrameList::Enumerator childFrames(lists.CurrentList());
           for (; !childFrames.AtEnd(); childFrames.Next()) {
             nsIFrame* kid = childFrames.get();
             kid->MarkIntrinsicWidthsDirty();
             stack.AppendElement(kid);
           }
         }
       } while (stack.Length() != 0);
     }
   }
   mFlags.mHResize = !(frame->GetStateBits() & NS_FRAME_IS_DIRTY) &&
                     isHResize;
   // XXX Should we really need to null check mCBReflowState?  (We do for
   // at least nsBoxFrame).
   if (IS_TABLE_CELL(aFrameType) &&
       (mFlags.mSpecialHeightReflow ||
        (frame->FirstInFlow()->GetStateBits() &
          NS_TABLE_CELL_HAD_SPECIAL_REFLOW)) &&
       (frame->GetStateBits() & NS_FRAME_CONTAINS_RELATIVE_HEIGHT)) {
     // Need to set the bit on the cell so that
     // mCBReflowState->mFlags.mVResize is set correctly below when
     // reflowing descendant.
     mFlags.mVResize = true;
   } else if (mCBReflowState && !nsLayoutUtils::IsNonWrapperBlock(frame)) {
     // XXX Is this problematic for relatively positioned inlines acting
     // as containing block for absolutely positioned elements?
     // Possibly; in that case we should at least be checking
     // NS_SUBTREE_DIRTY, I'd think.
     mFlags.mVResize = mCBReflowState->mFlags.mVResize;
   } else if (ComputedHeight() == NS_AUTOHEIGHT) {
     if (eCompatibility_NavQuirks == aPresContext->CompatibilityMode() &&
         mCBReflowState) {
       mFlags.mVResize = mCBReflowState->mFlags.mVResize;
     } else {
       mFlags.mVResize = mFlags.mHResize;
     }
     mFlags.mVResize = mFlags.mVResize || NS_SUBTREE_DIRTY(frame);
   } else {
     // not 'auto' height
     mFlags.mVResize = frame->GetSize().height !=
                         ComputedHeight() + ComputedPhysicalBorderPadding().TopBottom();
   }
   bool dependsOnCBHeight =
     (mStylePosition->HeightDependsOnContainer() &&
      // FIXME: condition this on not-abspos?
      mStylePosition->mHeight.GetUnit() != eStyleUnit_Auto) ||
     mStylePosition->MinHeightDependsOnContainer() ||
     mStylePosition->MaxHeightDependsOnContainer() ||
     mStylePosition->OffsetHasPercent(NS_SIDE_TOP) ||
     mStylePosition->mOffset.GetBottomUnit() != eStyleUnit_Auto ||
     frame->IsBoxFrame();
   if (mStyleText->mLineHeight.GetUnit() == eStyleUnit_Enumerated) {
     NS_ASSERTION(mStyleText->mLineHeight.GetIntValue() ==
                  NS_STYLE_LINE_HEIGHT_BLOCK_HEIGHT,
                  "bad line-height value");
     // line-height depends on block height
     frame->AddStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);
     // but only on containing blocks if this frame is not a suitable block
     dependsOnCBHeight |= !nsLayoutUtils::IsNonWrapperBlock(frame);
   }
   // If we're the descendant of a table cell that performs special height
   // reflows and we could be the child that requires them, always set
   // the vertical resize in case this is the first pass before the
   // special height reflow.  However, don't do this if it actually is
   // the special height reflow, since in that case it will already be
   // set correctly above if we need it set.
   if (!mFlags.mVResize && mCBReflowState &&
       (IS_TABLE_CELL(mCBReflowState->frame->GetType()) ||
        mCBReflowState->mFlags.mHeightDependsOnAncestorCell) &&
       !mCBReflowState->mFlags.mSpecialHeightReflow &&
       dependsOnCBHeight) {
     mFlags.mVResize = true;
     mFlags.mHeightDependsOnAncestorCell = true;
   }
   // Set NS_FRAME_CONTAINS_RELATIVE_HEIGHT if it's needed.
   // It would be nice to check that |mComputedHeight != NS_AUTOHEIGHT|
   // &&ed with the percentage height check.  However, this doesn't get
   // along with table special height reflows, since a special height
   // reflow (a quirk that makes such percentage heights work on children
   // of table cells) can cause not just a single percentage height to
   // become fixed, but an entire descendant chain of percentage heights
   // to become fixed.
   if (dependsOnCBHeight && mCBReflowState) {
     const nsHTMLReflowState *rs = this;
     bool hitCBReflowState = false;
     do {
       rs = rs->parentReflowState;
       if (!rs) {
         break;
       }
       if (rs->frame->GetStateBits() & NS_FRAME_CONTAINS_RELATIVE_HEIGHT)
         break; // no need to go further
       rs->frame->AddStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);
       // Keep track of whether we've hit the containing block, because
       // we need to go at least that far.
       if (rs == mCBReflowState) {
         hitCBReflowState = true;
       }
     } while (!hitCBReflowState ||
              (eCompatibility_NavQuirks == aPresContext->CompatibilityMode() &&
               !IsQuirkContainingBlockHeight(rs, rs->frame->GetType())));
     // Note: We actually don't need to set the
     // NS_FRAME_CONTAINS_RELATIVE_HEIGHT bit for the cases
     // where we hit the early break statements in
     // CalcQuirkContainingBlockHeight. But it doesn't hurt
     // us to set the bit in these cases.
   }
   if (frame->GetStateBits() & NS_FRAME_IS_DIRTY) {
     // If we're reflowing everything, then we'll find out if we need
     // to re-set this.
     frame->RemoveStateBits(NS_FRAME_CONTAINS_RELATIVE_HEIGHT);
   }
 }
 /* static */
 nscoord
 nsHTMLReflowState::GetContainingBlockContentWidth(const nsHTMLReflowState* aReflowState)
 {
   const nsHTMLReflowState* rs = aReflowState->mCBReflowState;
   if (!rs)
     return 0;
   return rs->ComputedWidth();
 }
 void
 nsHTMLReflowState::InitFrameType(nsIAtom* aFrameType)
 {
   const nsStyleDisplay *disp = mStyleDisplay;
   nsCSSFrameType frameType;
   // Section 9.7 of the CSS2 spec indicates that absolute position
   // takes precedence over float which takes precedence over display.
   // XXXldb nsRuleNode::ComputeDisplayData should take care of this, right?
   // Make sure the frame was actually moved out of the flow, and don't
   // just assume what the style says, because we might not have had a
   // useful float/absolute containing block
   DISPLAY_INIT_TYPE(frame, this);
   if (aFrameType == nsGkAtoms::tableFrame) {
     mFrameType = NS_CSS_FRAME_TYPE_BLOCK;
     return;
   }
   NS_ASSERTION(frame->StyleDisplay()->IsAbsolutelyPositionedStyle() ==
                  disp->IsAbsolutelyPositionedStyle(),
                "Unexpected position style");
   NS_ASSERTION(frame->StyleDisplay()->IsFloatingStyle() ==
                  disp->IsFloatingStyle(), "Unexpected float style");
   if (frame->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
     if (disp->IsAbsolutelyPositioned(frame)) {
       frameType = NS_CSS_FRAME_TYPE_ABSOLUTE;
       //XXXfr hack for making frames behave properly when in overflow container lists
       //      see bug 154892; need to revisit later
       if (frame->GetPrevInFlow())
         frameType = NS_CSS_FRAME_TYPE_BLOCK;
     }
     else if (disp->IsFloating(frame)) {
       frameType = NS_CSS_FRAME_TYPE_FLOATING;
     } else {
       NS_ASSERTION(disp->mDisplay == NS_STYLE_DISPLAY_POPUP,
                    "unknown out of flow frame type");
       frameType = NS_CSS_FRAME_TYPE_UNKNOWN;
     }
   }
   else {
     switch (GetDisplay()) {
     case NS_STYLE_DISPLAY_BLOCK:
     case NS_STYLE_DISPLAY_LIST_ITEM:
     case NS_STYLE_DISPLAY_TABLE:
     case NS_STYLE_DISPLAY_TABLE_CAPTION:
     case NS_STYLE_DISPLAY_FLEX:
       frameType = NS_CSS_FRAME_TYPE_BLOCK;
       break;
     case NS_STYLE_DISPLAY_INLINE:
     case NS_STYLE_DISPLAY_INLINE_BLOCK:
     case NS_STYLE_DISPLAY_INLINE_TABLE:
     case NS_STYLE_DISPLAY_INLINE_BOX:
     case NS_STYLE_DISPLAY_INLINE_XUL_GRID:
     case NS_STYLE_DISPLAY_INLINE_STACK:
     case NS_STYLE_DISPLAY_INLINE_FLEX:
       frameType = NS_CSS_FRAME_TYPE_INLINE;
       break;
     case NS_STYLE_DISPLAY_TABLE_CELL:
     case NS_STYLE_DISPLAY_TABLE_ROW_GROUP:
     case NS_STYLE_DISPLAY_TABLE_COLUMN:
     case NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP:
     case NS_STYLE_DISPLAY_TABLE_HEADER_GROUP:
     case NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP:
     case NS_STYLE_DISPLAY_TABLE_ROW:
       frameType = NS_CSS_FRAME_TYPE_INTERNAL_TABLE;
       break;
     case NS_STYLE_DISPLAY_NONE:
     default:
       frameType = NS_CSS_FRAME_TYPE_UNKNOWN;
       break;
     }
   }
   // See if the frame is replaced
   if (frame->IsFrameOfType(nsIFrame::eReplacedContainsBlock)) {
     frameType = NS_FRAME_REPLACED_CONTAINS_BLOCK(frameType);
   } else if (frame->IsFrameOfType(nsIFrame::eReplaced)) {
     frameType = NS_FRAME_REPLACED(frameType);
   }
   mFrameType = frameType;
 }
 /* static */ void
 nsHTMLReflowState::ComputeRelativeOffsets(uint8_t aCBDirection,
                                           nsIFrame* aFrame,
                                           nscoord aContainingBlockWidth,
                                           nscoord aContainingBlockHeight,
                                           nsMargin& aComputedOffsets)
 {
   const nsStylePosition* position = aFrame->StylePosition();
   // Compute the 'left' and 'right' values. 'Left' moves the boxes to the right,
   // and 'right' moves the boxes to the left. The computed values are always:
   // left=-right
   bool    leftIsAuto = eStyleUnit_Auto == position->mOffset.GetLeftUnit();
   bool    rightIsAuto = eStyleUnit_Auto == position->mOffset.GetRightUnit();
   // If neither 'left' not 'right' are auto, then we're over-constrained and
   // we ignore one of them
   if (!leftIsAuto && !rightIsAuto) {
     if (aCBDirection == NS_STYLE_DIRECTION_RTL) {
       leftIsAuto = true;
     } else {
       rightIsAuto = true;
     }
   }
   if (leftIsAuto) {
     if (rightIsAuto) {
       // If both are 'auto' (their initial values), the computed values are 0
       aComputedOffsets.left = aComputedOffsets.right = 0;
     } else {
       // 'Right' isn't 'auto' so compute its value
       aComputedOffsets.right = nsLayoutUtils::
         ComputeCBDependentValue(aContainingBlockWidth,
                                 position->mOffset.GetRight());
       // Computed value for 'left' is minus the value of 'right'
       aComputedOffsets.left = -aComputedOffsets.right;
     }
   } else {
     NS_ASSERTION(rightIsAuto, "unexpected specified constraint");
     // 'Left' isn't 'auto' so compute its value
     aComputedOffsets.left = nsLayoutUtils::
       ComputeCBDependentValue(aContainingBlockWidth,
                               position->mOffset.GetLeft());
     // Computed value for 'right' is minus the value of 'left'
     aComputedOffsets.right = -aComputedOffsets.left;
   }
   // Compute the 'top' and 'bottom' values. The 'top' and 'bottom' properties
   // move relatively positioned elements up and down. They also must be each
   // other's negative
   bool    topIsAuto = eStyleUnit_Auto == position->mOffset.GetTopUnit();
   bool    bottomIsAuto = eStyleUnit_Auto == position->mOffset.GetBottomUnit();
   // Check for percentage based values and a containing block height that
   // depends on the content height. Treat them like 'auto'
   if (NS_AUTOHEIGHT == aContainingBlockHeight) {
     if (position->OffsetHasPercent(NS_SIDE_TOP)) {
       topIsAuto = true;
     }
     if (position->OffsetHasPercent(NS_SIDE_BOTTOM)) {
       bottomIsAuto = true;
     }
   }
   // If neither is 'auto', 'bottom' is ignored
   if (!topIsAuto && !bottomIsAuto) {
     bottomIsAuto = true;
   }
   if (topIsAuto) {
     if (bottomIsAuto) {
       // If both are 'auto' (their initial values), the computed values are 0
       aComputedOffsets.top = aComputedOffsets.bottom = 0;
     } else {
       // 'Bottom' isn't 'auto' so compute its value
       aComputedOffsets.bottom = nsLayoutUtils::
         ComputeHeightDependentValue(aContainingBlockHeight,
                                     position->mOffset.GetBottom());
       // Computed value for 'top' is minus the value of 'bottom'
       aComputedOffsets.top = -aComputedOffsets.bottom;
     }
   } else {
     NS_ASSERTION(bottomIsAuto, "unexpected specified constraint");
     // 'Top' isn't 'auto' so compute its value
     aComputedOffsets.top = nsLayoutUtils::
       ComputeHeightDependentValue(aContainingBlockHeight,
                                   position->mOffset.GetTop());
     // Computed value for 'bottom' is minus the value of 'top'
     aComputedOffsets.bottom = -aComputedOffsets.top;
   }
   // Store the offset
   FrameProperties props = aFrame->Properties();
   nsMargin* offsets = static_cast<nsMargin*>
     (props.Get(nsIFrame::ComputedOffsetProperty()));
   if (offsets) {
     *offsets = aComputedOffsets;
   } else {
     props.Set(nsIFrame::ComputedOffsetProperty(),
               new nsMargin(aComputedOffsets));
   }
 }
 /* static */ void
 nsHTMLReflowState::ApplyRelativePositioning(nsIFrame* aFrame,
                                             const nsMargin& aComputedOffsets,
                                             nsPoint* aPosition)
 {
   if (!aFrame->IsRelativelyPositioned()) {
     NS_ASSERTION(!aFrame->Properties().Get(nsIFrame::NormalPositionProperty()),
                  "We assume that changing the 'position' property causes "
                  "frame reconstruction.  If that ever changes, this code "
                  "should call "
                  "props.Delete(nsIFrame::NormalPositionProperty())");
     return;
   }
   // Store the normal position
   FrameProperties props = aFrame->Properties();
   nsPoint* normalPosition = static_cast<nsPoint*>
     (props.Get(nsIFrame::NormalPositionProperty()));
   if (normalPosition) {
     *normalPosition = *aPosition;
   } else {
     props.Set(nsIFrame::NormalPositionProperty(), new nsPoint(*aPosition));
   }
   const nsStyleDisplay* display = aFrame->StyleDisplay();
   if (NS_STYLE_POSITION_RELATIVE == display->mPosition) {
     *aPosition += nsPoint(aComputedOffsets.left, aComputedOffsets.top);
   } else if (NS_STYLE_POSITION_STICKY == display->mPosition &&
              !aFrame->GetNextContinuation() &&
              !aFrame->GetPrevContinuation() &&
              !(aFrame->GetStateBits() & NS_FRAME_PART_OF_IBSPLIT)) {
     // Sticky positioning for elements with multiple frames needs to be
     // computed all at once. We can't safely do that here because we might be
     // partway through (re)positioning the frames, so leave it until the scroll
     // container reflows and calls StickyScrollContainer::UpdatePositions.
     // For single-frame sticky positioned elements, though, go ahead and apply
     // it now to avoid unnecessary overflow updates later.
     StickyScrollContainer* ssc =
       StickyScrollContainer::GetStickyScrollContainerForFrame(aFrame);
     if (ssc) {
       *aPosition = ssc->ComputePosition(aFrame);
     }
   }
 }
 nsIFrame*
 nsHTMLReflowState::GetHypotheticalBoxContainer(nsIFrame* aFrame,
                                                nscoord& aCBLeftEdge,
                                                nscoord& aCBWidth)
 {
   aFrame = aFrame->GetContainingBlock();
   NS_ASSERTION(aFrame != frame, "How did that happen?");
   /* Now aFrame is the containing block we want */
   /* Check whether the containing block is currently being reflowed.
      If so, use the info from the reflow state. */
   const nsHTMLReflowState* state;
   if (aFrame->GetStateBits() & NS_FRAME_IN_REFLOW) {
     for (state = parentReflowState; state && state->frame != aFrame;
          state = state->parentReflowState) {
       /* do nothing */
     }
   } else {
     state = nullptr;
   }
   if (state) {
     aCBLeftEdge = state->ComputedPhysicalBorderPadding().left;
     aCBWidth = state->ComputedWidth();
   } else {
     /* Didn't find a reflow state for aFrame.  Just compute the information we
        want, on the assumption that aFrame already knows its size.  This really
        ought to be true by now. */
     NS_ASSERTION(!(aFrame->GetStateBits() & NS_FRAME_IN_REFLOW),
                  "aFrame shouldn't be in reflow; we'll lie if it is");
     nsMargin borderPadding = aFrame->GetUsedBorderAndPadding();
     aCBLeftEdge = borderPadding.left;
     aCBWidth = aFrame->GetSize().width - borderPadding.LeftRight();
   }
   return aFrame;
 }
 // When determining the hypothetical box that would have been if the element
 // had been in the flow we may not be able to exactly determine both the left
 // and right edges. For example, if the element is a non-replaced inline-level
 // element we would have to reflow it in order to determine it desired width.
 // In that case depending on the progression direction either the left or
 // right edge would be marked as not being exact
 struct nsHypotheticalBox {
   // offsets from left edge of containing block (which is a padding edge)
   nscoord       mLeft, mRight;
   // offset from top edge of containing block (which is a padding edge)
   nscoord       mTop;
 #ifdef DEBUG
   bool          mLeftIsExact, mRightIsExact;
 #endif
   nsHypotheticalBox() {
 #ifdef DEBUG
     mLeftIsExact = mRightIsExact = false;
 #endif
   }
 };
 static bool
 GetIntrinsicSizeFor(nsIFrame* aFrame, nsSize& aIntrinsicSize, nsIAtom* aFrameType)
 {
   // See if it is an image frame
   bool success = false;
   // Currently the only type of replaced frame that we can get the intrinsic
   // size for is an image frame
   // XXX We should add back the GetReflowMetrics() function and one of the
   // things should be the intrinsic size...
   if (aFrameType == nsGkAtoms::imageFrame) {
     nsImageFrame* imageFrame = (nsImageFrame*)aFrame;
     if (NS_SUCCEEDED(imageFrame->GetIntrinsicImageSize(aIntrinsicSize))) {
       success = (aIntrinsicSize != nsSize(0, 0));
     }
   }
   return success;
 }
 /**
  * aInsideBoxSizing returns the part of the horizontal padding, border,
  * and margin that goes inside the edge given by box-sizing;
  * aOutsideBoxSizing returns the rest.
  */
 void
 nsHTMLReflowState::CalculateHorizBorderPaddingMargin(
                        nscoord aContainingBlockWidth,
                        nscoord* aInsideBoxSizing,
                        nscoord* aOutsideBoxSizing)
 {
   const nsMargin& border = mStyleBorder->GetComputedBorder();
   nsMargin padding, margin;
   // See if the style system can provide us the padding directly
   if (!mStylePadding->GetPadding(padding)) {
     // We have to compute the left and right values
     padding.left = nsLayoutUtils::
       ComputeCBDependentValue(aContainingBlockWidth,
                               mStylePadding->mPadding.GetLeft());
     padding.right = nsLayoutUtils::
       ComputeCBDependentValue(aContainingBlockWidth,
                               mStylePadding->mPadding.GetRight());
   }
   // See if the style system can provide us the margin directly
   if (!mStyleMargin->GetMargin(margin)) {
     // We have to compute the left and right values
     if (eStyleUnit_Auto == mStyleMargin->mMargin.GetLeftUnit()) {
       // XXX FIXME (or does CalculateBlockSideMargins do this?)
       margin.left = 0;  // just ignore
     } else {
       margin.left = nsLayoutUtils::
         ComputeCBDependentValue(aContainingBlockWidth,
                                 mStyleMargin->mMargin.GetLeft());
     }
     if (eStyleUnit_Auto == mStyleMargin->mMargin.GetRightUnit()) {
       // XXX FIXME (or does CalculateBlockSideMargins do this?)
       margin.right = 0;  // just ignore
     } else {
       margin.right = nsLayoutUtils::
         ComputeCBDependentValue(aContainingBlockWidth,
                                 mStyleMargin->mMargin.GetRight());
     }
   }
   nscoord outside =
     padding.LeftRight() + border.LeftRight() + margin.LeftRight();
   nscoord inside = 0;
   switch (mStylePosition->mBoxSizing) {
     case NS_STYLE_BOX_SIZING_BORDER:
       inside += border.LeftRight();
       // fall through
     case NS_STYLE_BOX_SIZING_PADDING:
       inside += padding.LeftRight();
   }
   outside -= inside;
   *aInsideBoxSizing = inside;
   *aOutsideBoxSizing = outside;
   return;
 }
 /**
  * Returns true iff a pre-order traversal of the normal child
  * frames rooted at aFrame finds no non-empty frame before aDescendant.
  */
 static bool AreAllEarlierInFlowFramesEmpty(nsIFrame* aFrame,
   nsIFrame* aDescendant, bool* aFound) {
   if (aFrame == aDescendant) {
     *aFound = true;
     return true;
   }
   if (!aFrame->IsSelfEmpty()) {
     *aFound = false;
     return false;
   }
   for (nsIFrame* f = aFrame->GetFirstPrincipalChild(); f; f = f->GetNextSibling()) {
     bool allEmpty = AreAllEarlierInFlowFramesEmpty(f, aDescendant, aFound);
     if (*aFound || !allEmpty) {
       return allEmpty;
     }
   }
   *aFound = false;
   return true;
 }
 // Calculate the hypothetical box that the element would have if it were in
 // the flow. The values returned are relative to the padding edge of the
 // absolute containing block
 // aContainingBlock is the placeholder's containing block (XXX rename it?)
 // cbrs->frame is the actual containing block
 void
 nsHTMLReflowState::CalculateHypotheticalBox(nsPresContext*    aPresContext,
                                             nsIFrame*         aPlaceholderFrame,
                                             nsIFrame*         aContainingBlock,
                                             nscoord           aBlockLeftContentEdge,
                                             nscoord           aBlockContentWidth,
                                             const nsHTMLReflowState* cbrs,
                                             nsHypotheticalBox& aHypotheticalBox,
                                             nsIAtom*          aFrameType)
 {
   NS_ASSERTION(mStyleDisplay->mOriginalDisplay != NS_STYLE_DISPLAY_NONE,
                "mOriginalDisplay has not been properly initialized");
   // If it's a replaced element and it has a 'auto' value for 'width', see if we
   // can get the intrinsic size. This will allow us to exactly determine both the
   // left and right edges
   bool isAutoWidth = mStylePosition->mWidth.GetUnit() == eStyleUnit_Auto;
   nsSize      intrinsicSize;
   bool        knowIntrinsicSize = false;
   if (NS_FRAME_IS_REPLACED(mFrameType) && isAutoWidth) {
     // See if we can get the intrinsic size of the element
     knowIntrinsicSize = GetIntrinsicSizeFor(frame, intrinsicSize, aFrameType);
   }
   // See if we can calculate what the box width would have been if the
   // element had been in the flow
   nscoord boxWidth;
   bool    knowBoxWidth = false;
   if ((NS_STYLE_DISPLAY_INLINE == mStyleDisplay->mOriginalDisplay) &&
       !NS_FRAME_IS_REPLACED(mFrameType)) {
     // For non-replaced inline-level elements the 'width' property doesn't apply,
     // so we don't know what the width would have been without reflowing it
   } else {
     // It's either a replaced inline-level element or a block-level element
     // Determine the total amount of horizontal border/padding/margin that
     // the element would have had if it had been in the flow. Note that we
     // ignore any 'auto' and 'inherit' values
     nscoord insideBoxSizing, outsideBoxSizing;
     CalculateHorizBorderPaddingMargin(aBlockContentWidth,
                                       &insideBoxSizing, &outsideBoxSizing);
     if (NS_FRAME_IS_REPLACED(mFrameType) && isAutoWidth) {
       // It's a replaced element with an 'auto' width so the box width is
       // its intrinsic size plus any border/padding/margin
       if (knowIntrinsicSize) {
         boxWidth = intrinsicSize.width + outsideBoxSizing + insideBoxSizing;
         knowBoxWidth = true;
       }
     } else if (isAutoWidth) {
       // The box width is the containing block width
       boxWidth = aBlockContentWidth;
       knowBoxWidth = true;
     } else {
       // We need to compute it. It's important we do this, because if it's
       // percentage based this computed value may be different from the computed
       // value calculated using the absolute containing block width
       boxWidth = ComputeWidthValue(aBlockContentWidth,
                                    insideBoxSizing, outsideBoxSizing,
                                    mStylePosition->mWidth) +
                  insideBoxSizing + outsideBoxSizing;
       knowBoxWidth = true;
     }
   }
   // Get the 'direction' of the block
   const nsStyleVisibility* blockVis = aContainingBlock->StyleVisibility();
   // Get the placeholder x-offset and y-offset in the coordinate
   // space of its containing block
   // XXXbz the placeholder is not fully reflowed yet if our containing block is
   // relatively positioned...
   nsPoint placeholderOffset = aPlaceholderFrame->GetOffsetTo(aContainingBlock);
   // First, determine the hypothetical box's mTop.  We want to check the
   // content insertion frame of aContainingBlock for block-ness, but make
   // sure to compute all coordinates in the coordinate system of
   // aContainingBlock.
   nsBlockFrame* blockFrame =
     nsLayoutUtils::GetAsBlock(aContainingBlock->GetContentInsertionFrame());
   if (blockFrame) {
     nscoord blockYOffset = blockFrame->GetOffsetTo(aContainingBlock).y;
     bool isValid;
     nsBlockInFlowLineIterator iter(blockFrame, aPlaceholderFrame, &isValid);
     if (!isValid) {
       // Give up.  We're probably dealing with somebody using
       // position:absolute inside native-anonymous content anyway.
       aHypotheticalBox.mTop = placeholderOffset.y;
     } else {
       NS_ASSERTION(iter.GetContainer() == blockFrame,
                    "Found placeholder in wrong block!");
       nsBlockFrame::line_iterator lineBox = iter.GetLine();
       // How we determine the hypothetical box depends on whether the element
       // would have been inline-level or block-level
       if (mStyleDisplay->IsOriginalDisplayInlineOutsideStyle()) {
         // Use the top of the inline box which the placeholder lives in
         // as the hypothetical box's top.
         aHypotheticalBox.mTop = lineBox->GetPhysicalBounds().y + blockYOffset;
       } else {
         // The element would have been block-level which means it would
         // be below the line containing the placeholder frame, unless
         // all the frames before it are empty.  In that case, it would
         // have been just before this line.
         // XXXbz the line box is not fully reflowed yet if our
         // containing block is relatively positioned...
         if (lineBox != iter.End()) {
           nsIFrame * firstFrame = lineBox->mFirstChild;
           bool found = false;
           bool allEmpty = true;
           while (firstFrame) { // See bug 223064
             allEmpty = AreAllEarlierInFlowFramesEmpty(firstFrame,
               aPlaceholderFrame, &found);
             if (found || !allEmpty)
               break;
             firstFrame = firstFrame->GetNextSibling();
           }
           NS_ASSERTION(firstFrame, "Couldn't find placeholder!");
           if (allEmpty) {
             // The top of the hypothetical box is the top of the line
             // containing the placeholder, since there is nothing in the
             // line before our placeholder except empty frames.
             aHypotheticalBox.mTop = lineBox->GetPhysicalBounds().y + blockYOffset;
           } else {
             // The top of the hypothetical box is just below the line
             // containing the placeholder.
             aHypotheticalBox.mTop = lineBox->GetPhysicalBounds().YMost() + blockYOffset;
           }
         } else {
           // Just use the placeholder's y-offset wrt the containing block
           aHypotheticalBox.mTop = placeholderOffset.y;
         }
       }
     }
   } else {
     // The containing block is not a block, so it's probably something
     // like a XUL box, etc.
     // Just use the placeholder's y-offset
     aHypotheticalBox.mTop = placeholderOffset.y;
   }
   // Second, determine the hypothetical box's mLeft & mRight
   // To determine the left and right offsets we need to look at the block's 'direction'
   if (NS_STYLE_DIRECTION_LTR == blockVis->mDirection) {
     // How we determine the hypothetical box depends on whether the element
     // would have been inline-level or block-level
     if (mStyleDisplay->IsOriginalDisplayInlineOutsideStyle()) {
       // The placeholder represents the left edge of the hypothetical box
       aHypotheticalBox.mLeft = placeholderOffset.x;
     } else {
       aHypotheticalBox.mLeft = aBlockLeftContentEdge;
     }
 #ifdef DEBUG
     aHypotheticalBox.mLeftIsExact = true;
 #endif
     if (knowBoxWidth) {
       aHypotheticalBox.mRight = aHypotheticalBox.mLeft + boxWidth;
 #ifdef DEBUG
       aHypotheticalBox.mRightIsExact = true;
 #endif
     } else {
       // We can't compute the right edge because we don't know the desired
       // width. So instead use the right content edge of the block parent,
       // but remember it's not exact
       aHypotheticalBox.mRight = aBlockLeftContentEdge + aBlockContentWidth;
 #ifdef DEBUG
       aHypotheticalBox.mRightIsExact = false;
 #endif
     }
   } else {
     // The placeholder represents the right edge of the hypothetical box
     if (mStyleDisplay->IsOriginalDisplayInlineOutsideStyle()) {
       aHypotheticalBox.mRight = placeholderOffset.x;
     } else {
       aHypotheticalBox.mRight = aBlockLeftContentEdge + aBlockContentWidth;
     }
 #ifdef DEBUG
     aHypotheticalBox.mRightIsExact = true;
 #endif
     if (knowBoxWidth) {
       aHypotheticalBox.mLeft = aHypotheticalBox.mRight - boxWidth;
 #ifdef DEBUG
       aHypotheticalBox.mLeftIsExact = true;
 #endif
     } else {
       // We can't compute the left edge because we don't know the desired
       // width. So instead use the left content edge of the block parent,
       // but remember it's not exact
       aHypotheticalBox.mLeft = aBlockLeftContentEdge;
 #ifdef DEBUG
       aHypotheticalBox.mLeftIsExact = false;
 #endif
     }
   }
   // The current coordinate space is that of the nearest block to the placeholder.
   // Convert to the coordinate space of the absolute containing block
   // One weird thing here is that for fixed-positioned elements we want to do
   // the conversion incorrectly; specifically we want to ignore any scrolling
   // that may have happened;
   nsPoint cbOffset;
   if (mStyleDisplay->mPosition == NS_STYLE_POSITION_FIXED &&
       // Exclude cases inside -moz-transform where fixed is like absolute.
       nsLayoutUtils::IsReallyFixedPos(frame)) {
     // In this case, cbrs->frame will always be an ancestor of
     // aContainingBlock, so can just walk our way up the frame tree.
     // Make sure to not add positions of frames whose parent is a
     // scrollFrame, since we're doing fixed positioning, which assumes
     // everything is scrolled to (0,0).
     cbOffset.MoveTo(0, 0);
     do {
       NS_ASSERTION(aContainingBlock,
                    "Should hit cbrs->frame before we run off the frame tree!");
       cbOffset += aContainingBlock->GetPositionIgnoringScrolling();
       aContainingBlock = aContainingBlock->GetParent();
     } while (aContainingBlock != cbrs->frame);
   } else {
     // XXXldb We need to either ignore scrolling for the absolute
     // positioning case too (and take the incompatibility) or figure out
     // how to make these positioned elements actually *move* when we
     // scroll, and thus avoid the resulting incremental reflow bugs.
     cbOffset = aContainingBlock->GetOffsetTo(cbrs->frame);
   }
   aHypotheticalBox.mLeft += cbOffset.x;
   aHypotheticalBox.mTop += cbOffset.y;
   aHypotheticalBox.mRight += cbOffset.x;
   // The specified offsets are relative to the absolute containing block's
   // padding edge and our current values are relative to the border edge, so
   // translate.
   nsMargin border = cbrs->ComputedPhysicalBorderPadding() - cbrs->ComputedPhysicalPadding();
   aHypotheticalBox.mLeft -= border.left;
   aHypotheticalBox.mRight -= border.left;
   aHypotheticalBox.mTop -= border.top;
 }
 void
 nsHTMLReflowState::InitAbsoluteConstraints(nsPresContext* aPresContext,
                                            const nsHTMLReflowState* cbrs,
                                            nscoord containingBlockWidth,
                                            nscoord containingBlockHeight,
                                            nsIAtom* aFrameType)
 {
   NS_PRECONDITION(containingBlockHeight != NS_AUTOHEIGHT,
                   "containing block height must be constrained");
   NS_ASSERTION(aFrameType != nsGkAtoms::tableFrame,
                "InitAbsoluteConstraints should not be called on table frames");
   NS_ASSERTION(frame->GetStateBits() & NS_FRAME_OUT_OF_FLOW,
                "Why are we here?");
   // Get the placeholder frame
   nsIFrame*     placeholderFrame;
   placeholderFrame = aPresContext->PresShell()->GetPlaceholderFrameFor(frame);
   NS_ASSERTION(nullptr != placeholderFrame, "no placeholder frame");
   // If both 'left' and 'right' are 'auto' or both 'top' and 'bottom' are
   // 'auto', then compute the hypothetical box of where the element would
   // have been if it had been in the flow
   nsHypotheticalBox hypotheticalBox;
   if (((eStyleUnit_Auto == mStylePosition->mOffset.GetLeftUnit()) &&
        (eStyleUnit_Auto == mStylePosition->mOffset.GetRightUnit())) ||
       ((eStyleUnit_Auto == mStylePosition->mOffset.GetTopUnit()) &&
        (eStyleUnit_Auto == mStylePosition->mOffset.GetBottomUnit()))) {
     // Find the nearest containing block frame to the placeholder frame,
     // and return its left edge and width.
     nscoord cbLeftEdge, cbWidth;
     nsIFrame* cbFrame = GetHypotheticalBoxContainer(placeholderFrame,
                                                     cbLeftEdge,
                                                     cbWidth);
     CalculateHypotheticalBox(aPresContext, placeholderFrame, cbFrame,
                              cbLeftEdge, cbWidth, cbrs, hypotheticalBox, aFrameType);
   }
   // Initialize the 'left' and 'right' computed offsets
   // XXX Handle new 'static-position' value...
   bool          leftIsAuto = false, rightIsAuto = false;
   if (eStyleUnit_Auto == mStylePosition->mOffset.GetLeftUnit()) {
     ComputedPhysicalOffsets().left = 0;
     leftIsAuto = true;
   } else {
     ComputedPhysicalOffsets().left = nsLayoutUtils::
       ComputeCBDependentValue(containingBlockWidth,
                               mStylePosition->mOffset.GetLeft());
   }
   if (eStyleUnit_Auto == mStylePosition->mOffset.GetRightUnit()) {
     ComputedPhysicalOffsets().right = 0;
     rightIsAuto = true;
   } else {
     ComputedPhysicalOffsets().right = nsLayoutUtils::
       ComputeCBDependentValue(containingBlockWidth,
                               mStylePosition->mOffset.GetRight());
   }
   // Use the horizontal component of the hypothetical box in the cases
   // where it's needed.
   if (leftIsAuto && rightIsAuto) {
     // Use the direction of the original ("static-position") containing block
     // to dictate whether 'left' or 'right' is treated like 'static-position'.
     if (NS_STYLE_DIRECTION_LTR == placeholderFrame->GetContainingBlock()
                                     ->StyleVisibility()->mDirection) {
       NS_ASSERTION(hypotheticalBox.mLeftIsExact, "should always have "
                    "exact value on containing block's start side");
       ComputedPhysicalOffsets().left = hypotheticalBox.mLeft;
       leftIsAuto = false;
     } else {
       NS_ASSERTION(hypotheticalBox.mRightIsExact, "should always have "
                    "exact value on containing block's start side");
       ComputedPhysicalOffsets().right = containingBlockWidth - hypotheticalBox.mRight;
       rightIsAuto = false;
     }
   }
   // Initialize the 'top' and 'bottom' computed offsets
   bool        topIsAuto = false, bottomIsAuto = false;
   if (eStyleUnit_Auto == mStylePosition->mOffset.GetTopUnit()) {
     ComputedPhysicalOffsets().top = 0;
     topIsAuto = true;
   } else {
     ComputedPhysicalOffsets().top = nsLayoutUtils::
       ComputeHeightDependentValue(containingBlockHeight,
                                   mStylePosition->mOffset.GetTop());
   }
   if (eStyleUnit_Auto == mStylePosition->mOffset.GetBottomUnit()) {
     ComputedPhysicalOffsets().bottom = 0;
     bottomIsAuto = true;
   } else {
     ComputedPhysicalOffsets().bottom = nsLayoutUtils::
       ComputeHeightDependentValue(containingBlockHeight,
                                   mStylePosition->mOffset.GetBottom());
   }
   if (topIsAuto && bottomIsAuto) {
     // Treat 'top' like 'static-position'
     ComputedPhysicalOffsets().top = hypotheticalBox.mTop;
     topIsAuto = false;
   }
   bool widthIsAuto = eStyleUnit_Auto == mStylePosition->mWidth.GetUnit();
   bool heightIsAuto = eStyleUnit_Auto == mStylePosition->mHeight.GetUnit();
   uint32_t computeSizeFlags = 0;
   if (leftIsAuto || rightIsAuto) {
     computeSizeFlags |= nsIFrame::eShrinkWrap;
   }
   {
     AutoMaybeDisableFontInflation an(frame);
     nsSize size =
       frame->ComputeSize(rendContext,
                          nsSize(containingBlockWidth,
                                 containingBlockHeight),
                          containingBlockWidth, // XXX or mAvailableWidth?
                          nsSize(ComputedPhysicalMargin().LeftRight() +
                                   ComputedPhysicalOffsets().LeftRight(),
                                 ComputedPhysicalMargin().TopBottom() +
                                   ComputedPhysicalOffsets().TopBottom()),
                          nsSize(ComputedPhysicalBorderPadding().LeftRight() -
                                   ComputedPhysicalPadding().LeftRight(),
                                 ComputedPhysicalBorderPadding().TopBottom() -
                                   ComputedPhysicalPadding().TopBottom()),
                          nsSize(ComputedPhysicalPadding().LeftRight(),
                                 ComputedPhysicalPadding().TopBottom()),
                          computeSizeFlags);
     ComputedWidth() = size.width;
     ComputedHeight() = size.height;
   }
   NS_ASSERTION(ComputedWidth() >= 0, "Bogus width");
   NS_ASSERTION(ComputedHeight() == NS_UNCONSTRAINEDSIZE ||
                ComputedHeight() >= 0, "Bogus height");
   // XXX Now that we have ComputeSize, can we condense many of the
   // branches off of widthIsAuto?
   if (leftIsAuto) {
     // We know 'right' is not 'auto' anymore thanks to the hypothetical
     // box code above.
     // Solve for 'left'.
     if (widthIsAuto) {
       // XXXldb This, and the corresponding code in
       // nsAbsoluteContainingBlock.cpp, could probably go away now that
       // we always compute widths.
       ComputedPhysicalOffsets().left = NS_AUTOOFFSET;
     } else {
       ComputedPhysicalOffsets().left = containingBlockWidth - ComputedPhysicalMargin().left -
         ComputedPhysicalBorderPadding().left - ComputedWidth() - ComputedPhysicalBorderPadding().right -
         ComputedPhysicalMargin().right - ComputedPhysicalOffsets().right;
     }
   } else if (rightIsAuto) {
     // We know 'left' is not 'auto' anymore thanks to the hypothetical
     // box code above.
     // Solve for 'right'.
     if (widthIsAuto) {
       // XXXldb This, and the corresponding code in
       // nsAbsoluteContainingBlock.cpp, could probably go away now that
       // we always compute widths.
       ComputedPhysicalOffsets().right = NS_AUTOOFFSET;
     } else {
       ComputedPhysicalOffsets().right = containingBlockWidth - ComputedPhysicalOffsets().left -
         ComputedPhysicalMargin().left - ComputedPhysicalBorderPadding().left - ComputedWidth() -
         ComputedPhysicalBorderPadding().right - ComputedPhysicalMargin().right;
     }
   } else {
     // Neither 'left' nor 'right' is 'auto'.  However, the width might
     // still not fill all the available space (even though we didn't
     // shrink-wrap) in case:
     //  * width was specified
     //  * we're dealing with a replaced element
     //  * width was constrained by min-width or max-width.
     nscoord availMarginSpace = containingBlockWidth -
                                ComputedPhysicalOffsets().LeftRight() -
                                ComputedPhysicalMargin().LeftRight() -
                                ComputedPhysicalBorderPadding().LeftRight() -
                                ComputedWidth();
     bool marginLeftIsAuto =
       eStyleUnit_Auto == mStyleMargin->mMargin.GetLeftUnit();
     bool marginRightIsAuto =
       eStyleUnit_Auto == mStyleMargin->mMargin.GetRightUnit();
     if (marginLeftIsAuto) {
       if (marginRightIsAuto) {
         if (availMarginSpace < 0) {
           // Note that this case is different from the neither-'auto'
           // case below, where the spec says to ignore 'left'/'right'.
           if (cbrs &&
               NS_STYLE_DIRECTION_RTL == cbrs->mStyleVisibility->mDirection) {
             // Ignore the specified value for 'margin-left'.
             ComputedPhysicalMargin().left = availMarginSpace;
           } else {
             // Ignore the specified value for 'margin-right'.
             ComputedPhysicalMargin().right = availMarginSpace;
           }
         } else {
           // Both 'margin-left' and 'margin-right' are 'auto', so they get
           // equal values
           ComputedPhysicalMargin().left = availMarginSpace / 2;
           ComputedPhysicalMargin().right = availMarginSpace - ComputedPhysicalMargin().left;
         }
       } else {
         // Just 'margin-left' is 'auto'
         ComputedPhysicalMargin().left = availMarginSpace;
       }
     } else {
       if (marginRightIsAuto) {
         // Just 'margin-right' is 'auto'
         ComputedPhysicalMargin().right = availMarginSpace;
       } else {
         // We're over-constrained so use the direction of the containing
         // block to dictate which value to ignore.  (And note that the
         // spec says to ignore 'left' or 'right' rather than
         // 'margin-left' or 'margin-right'.)
         // Note that this case is different from the both-'auto' case
         // above, where the spec says to ignore
         // 'margin-left'/'margin-right'.
         if (cbrs &&
             NS_STYLE_DIRECTION_RTL == cbrs->mStyleVisibility->mDirection) {
           // Ignore the specified value for 'left'.
           ComputedPhysicalOffsets().left += availMarginSpace;
         } else {
           // Ignore the specified value for 'right'.
           ComputedPhysicalOffsets().right += availMarginSpace;
         }
       }
     }
   }
   if (topIsAuto) {
     // solve for 'top'
     if (heightIsAuto) {
       ComputedPhysicalOffsets().top = NS_AUTOOFFSET;
     } else {
       ComputedPhysicalOffsets().top = containingBlockHeight - ComputedPhysicalMargin().top -
         ComputedPhysicalBorderPadding().top - ComputedHeight() - ComputedPhysicalBorderPadding().bottom -
         ComputedPhysicalMargin().bottom - ComputedPhysicalOffsets().bottom;
     }
   } else if (bottomIsAuto) {
     // solve for 'bottom'
     if (heightIsAuto) {
       ComputedPhysicalOffsets().bottom = NS_AUTOOFFSET;
     } else {
       ComputedPhysicalOffsets().bottom = containingBlockHeight - ComputedPhysicalOffsets().top -
         ComputedPhysicalMargin().top - ComputedPhysicalBorderPadding().top - ComputedHeight() -
         ComputedPhysicalBorderPadding().bottom - ComputedPhysicalMargin().bottom;
     }
   } else {
     // Neither 'top' nor 'bottom' is 'auto'.
     nscoord autoHeight = containingBlockHeight -
                          ComputedPhysicalOffsets().TopBottom() -
                          ComputedPhysicalMargin().TopBottom() -
                          ComputedPhysicalBorderPadding().TopBottom();
     if (autoHeight < 0) {
       autoHeight = 0;
     }
     if (ComputedHeight() == NS_UNCONSTRAINEDSIZE) {
       // For non-replaced elements with 'height' auto, the 'height'
       // fills the remaining space.
       ComputedHeight() = autoHeight;
       // XXX Do these need box-sizing adjustments?
       if (ComputedHeight() > ComputedMaxHeight())
         ComputedHeight() = ComputedMaxHeight();
       if (ComputedHeight() < ComputedMinHeight())
         ComputedHeight() = ComputedMinHeight();
     }
     // The height might still not fill all the available space in case:
     //  * height was specified
     //  * we're dealing with a replaced element
     //  * height was constrained by min-height or max-height.
     nscoord availMarginSpace = autoHeight - ComputedHeight();
     bool marginTopIsAuto =
       eStyleUnit_Auto == mStyleMargin->mMargin.GetTopUnit();
     bool marginBottomIsAuto =
       eStyleUnit_Auto == mStyleMargin->mMargin.GetBottomUnit();
     if (marginTopIsAuto) {
       if (marginBottomIsAuto) {
         if (availMarginSpace < 0) {
           // FIXME: Note that the spec doesn't actually say we should do this!
           ComputedPhysicalMargin().bottom = availMarginSpace;
         } else {
           // Both 'margin-top' and 'margin-bottom' are 'auto', so they get
           // equal values
           ComputedPhysicalMargin().top = availMarginSpace / 2;
           ComputedPhysicalMargin().bottom = availMarginSpace - ComputedPhysicalMargin().top;
         }
       } else {
         // Just 'margin-top' is 'auto'
         ComputedPhysicalMargin().top = availMarginSpace;
       }
     } else {
       if (marginBottomIsAuto) {
         // Just 'margin-bottom' is 'auto'
         ComputedPhysicalMargin().bottom = availMarginSpace;
       } else {
         // We're over-constrained so ignore the specified value for
         // 'bottom'.  (And note that the spec says to ignore 'bottom'
         // rather than 'margin-bottom'.)
         ComputedPhysicalOffsets().bottom += availMarginSpace;
       }
     }
   }
 }
 nscoord
 GetVerticalMarginBorderPadding(const nsHTMLReflowState* aReflowState)
 {
   nscoord result = 0;
   if (!aReflowState) return result;
   // zero auto margins
   nsMargin margin = aReflowState->ComputedPhysicalMargin();
   if (NS_AUTOMARGIN == margin.top)
     margin.top = 0;
   if (NS_AUTOMARGIN == margin.bottom)
     margin.bottom = 0;
   result += margin.top + margin.bottom;
   result += aReflowState->ComputedPhysicalBorderPadding().top +
             aReflowState->ComputedPhysicalBorderPadding().bottom;
   return result;
 }
 /* Get the height based on the viewport of the containing block specified
  * in aReflowState when the containing block has mComputedHeight == NS_AUTOHEIGHT
  * This will walk up the chain of containing blocks looking for a computed height
  * until it finds the canvas frame, or it encounters a frame that is not a block,
  * area, or scroll frame. This handles compatibility with IE (see bug 85016 and bug 219693)
  *
  *  When we encounter scrolledContent block frames, we skip over them, since they are guaranteed to not be useful for computing the containing block.
  *
  * See also IsQuirkContainingBlockHeight.
  */
 static nscoord
 CalcQuirkContainingBlockHeight(const nsHTMLReflowState* aCBReflowState)
 {
   const nsHTMLReflowState* firstAncestorRS = nullptr; // a candidate for html frame
   const nsHTMLReflowState* secondAncestorRS = nullptr; // a candidate for body frame
   // initialize the default to NS_AUTOHEIGHT as this is the containings block
   // computed height when this function is called. It is possible that we
   // don't alter this height especially if we are restricted to one level
   nscoord result = NS_AUTOHEIGHT;
   const nsHTMLReflowState* rs = aCBReflowState;
   for (; rs; rs = rs->parentReflowState) {
     nsIAtom* frameType = rs->frame->GetType();
     // if the ancestor is auto height then skip it and continue up if it
     // is the first block frame and possibly the body/html
     if (nsGkAtoms::blockFrame == frameType ||
 #ifdef MOZ_XUL
         nsGkAtoms::XULLabelFrame == frameType ||
 #endif
         nsGkAtoms::scrollFrame == frameType) {
       secondAncestorRS = firstAncestorRS;
       firstAncestorRS = rs;
       // If the current frame we're looking at is positioned, we don't want to
       // go any further (see bug 221784).  The behavior we want here is: 1) If
       // not auto-height, use this as the percentage base.  2) If auto-height,
       // keep looking, unless the frame is positioned.
       if (NS_AUTOHEIGHT == rs->ComputedHeight()) {
         if (rs->frame->IsAbsolutelyPositioned()) {
           break;
         } else {
           continue;
         }
       }
     }
     else if (nsGkAtoms::canvasFrame == frameType) {
       // Always continue on to the height calculation
     }
     else if (nsGkAtoms::pageContentFrame == frameType) {
       nsIFrame* prevInFlow = rs->frame->GetPrevInFlow();
       // only use the page content frame for a height basis if it is the first in flow
       if (prevInFlow)
         break;
     }
     else {
       break;
     }
     // if the ancestor is the page content frame then the percent base is
     // the avail height, otherwise it is the computed height
     result = (nsGkAtoms::pageContentFrame == frameType)
              ? rs->AvailableHeight() : rs->ComputedHeight();
     // if unconstrained - don't sutract borders - would result in huge height
     if (NS_AUTOHEIGHT == result) return result;
     // if we got to the canvas or page content frame, then subtract out
     // margin/border/padding for the BODY and HTML elements
     if ((nsGkAtoms::canvasFrame == frameType) ||
         (nsGkAtoms::pageContentFrame == frameType)) {
       result -= GetVerticalMarginBorderPadding(firstAncestorRS);
       result -= GetVerticalMarginBorderPadding(secondAncestorRS);
 #ifdef DEBUG
       // make sure the first ancestor is the HTML and the second is the BODY
       if (firstAncestorRS) {
         nsIContent* frameContent = firstAncestorRS->frame->GetContent();
         if (frameContent) {
           nsIAtom *contentTag = frameContent->Tag();
           NS_ASSERTION(contentTag == nsGkAtoms::html, "First ancestor is not HTML");
         }
       }
       if (secondAncestorRS) {
         nsIContent* frameContent = secondAncestorRS->frame->GetContent();
         if (frameContent) {
           nsIAtom *contentTag = frameContent->Tag();
           NS_ASSERTION(contentTag == nsGkAtoms::body, "Second ancestor is not BODY");
         }
       }
 #endif
     }
     // if we got to the html frame (a block child of the canvas) ...
     else if (nsGkAtoms::blockFrame == frameType &&
              rs->parentReflowState &&
              nsGkAtoms::canvasFrame ==
                rs->parentReflowState->frame->GetType()) {
       // ... then subtract out margin/border/padding for the BODY element
       result -= GetVerticalMarginBorderPadding(secondAncestorRS);
     }
     break;
   }
   // Make sure not to return a negative height here!
   return std::max(result, 0);
 }
 // Called by InitConstraints() to compute the containing block rectangle for
 // the element. Handles the special logic for absolutely positioned elements
 void
 nsHTMLReflowState::ComputeContainingBlockRectangle(nsPresContext*          aPresContext,
                                                    const nsHTMLReflowState* aContainingBlockRS,
                                                    nscoord&                 aContainingBlockWidth,
                                                    nscoord&                 aContainingBlockHeight)
 {
   // Unless the element is absolutely positioned, the containing block is
   // formed by the content edge of the nearest block-level ancestor
   aContainingBlockWidth = aContainingBlockRS->ComputedWidth();
   aContainingBlockHeight = aContainingBlockRS->ComputedHeight();
   // mFrameType for abs-pos tables is NS_CSS_FRAME_TYPE_BLOCK, so we need to
   // special case them here.
   if (NS_FRAME_GET_TYPE(mFrameType) == NS_CSS_FRAME_TYPE_ABSOLUTE ||
       (frame->GetType() == nsGkAtoms::tableFrame &&
        frame->IsAbsolutelyPositioned() &&
        (frame->GetParent()->GetStateBits() & NS_FRAME_OUT_OF_FLOW))) {
     // See if the ancestor is block-level or inline-level
     if (NS_FRAME_GET_TYPE(aContainingBlockRS->mFrameType) == NS_CSS_FRAME_TYPE_INLINE) {
       // Base our size on the actual size of the frame.  In cases when this is
       // completely bogus (eg initial reflow), this code shouldn't even be
       // called, since the code in nsInlineFrame::Reflow will pass in
       // the containing block dimensions to our constructor.
       // XXXbz we should be taking the in-flows into account too, but
       // that's very hard.
       nsMargin computedBorder = aContainingBlockRS->ComputedPhysicalBorderPadding() -
         aContainingBlockRS->ComputedPhysicalPadding();
       aContainingBlockWidth = aContainingBlockRS->frame->GetRect().width -
         computedBorder.LeftRight();
       NS_ASSERTION(aContainingBlockWidth >= 0,
                    "Negative containing block width!");
       aContainingBlockHeight = aContainingBlockRS->frame->GetRect().height -
         computedBorder.TopBottom();
       NS_ASSERTION(aContainingBlockHeight >= 0,
                    "Negative containing block height!");
     } else {
       // If the ancestor is block-level, the containing block is formed by the
       // padding edge of the ancestor
       aContainingBlockWidth += aContainingBlockRS->ComputedPhysicalPadding().LeftRight();
       aContainingBlockHeight += aContainingBlockRS->ComputedPhysicalPadding().TopBottom();
     }
   } else {
     // an element in quirks mode gets a containing block based on looking for a
     // parent with a non-auto height if the element has a percent height
     // Note: We don't emulate this quirk for percents in calc().
     if (NS_AUTOHEIGHT == aContainingBlockHeight) {
       if (eCompatibility_NavQuirks == aPresContext->CompatibilityMode() &&
           mStylePosition->mHeight.GetUnit() == eStyleUnit_Percent) {
         aContainingBlockHeight = CalcQuirkContainingBlockHeight(aContainingBlockRS);
       }
     }
   }
 }
 static eNormalLineHeightControl GetNormalLineHeightCalcControl(void)
 {
   if (sNormalLineHeightControl == eUninitialized) {
     // browser.display.normal_lineheight_calc_control is not user
     // changeable, so no need to register callback for it.
     int32_t val =
       Preferences::GetInt("browser.display.normal_lineheight_calc_control",
                           eNoExternalLeading);
     sNormalLineHeightControl = static_cast<eNormalLineHeightControl>(val);
   }
   return sNormalLineHeightControl;
 }
 static inline bool
 IsSideCaption(nsIFrame* aFrame, const nsStyleDisplay* aStyleDisplay)
 {
   if (aStyleDisplay->mDisplay != NS_STYLE_DISPLAY_TABLE_CAPTION)
     return false;
   uint8_t captionSide = aFrame->StyleTableBorder()->mCaptionSide;
   return captionSide == NS_STYLE_CAPTION_SIDE_LEFT ||
          captionSide == NS_STYLE_CAPTION_SIDE_RIGHT;
 }
 static nsFlexContainerFrame*
 GetFlexContainer(nsIFrame* aFrame)
 {
   nsIFrame* parent = aFrame->GetParent();
   if (!parent ||
       parent->GetType() != nsGkAtoms::flexContainerFrame) {
     return nullptr;
   }
   return static_cast<nsFlexContainerFrame*>(parent);
 }
 // Flex items resolve percentage margin & padding against the flex
 // container's height (which is the containing block height).
 // For everything else: the CSS21 spec requires that margin and padding
 // percentage values are calculated with respect to the *width* of the
 // containing block, even for margin & padding in the vertical axis.
 static nscoord
 VerticalOffsetPercentBasis(const nsIFrame* aFrame,
                            nscoord aContainingBlockWidth,
                            nscoord aContainingBlockHeight)
 {
   if (!aFrame->IsFlexItem()) {
     return aContainingBlockWidth;
   }
   if (aContainingBlockHeight == NS_AUTOHEIGHT) {
     return 0;
   }
   return aContainingBlockHeight;
 }
 // XXX refactor this code to have methods for each set of properties
 // we are computing: width,height,line-height; margin; offsets
 void
 nsHTMLReflowState::InitConstraints(nsPresContext* aPresContext,
                                    nscoord         aContainingBlockWidth,
                                    nscoord         aContainingBlockHeight,
                                    const nsMargin* aBorder,
                                    const nsMargin* aPadding,
                                    nsIAtom* aFrameType)
 {
   DISPLAY_INIT_CONSTRAINTS(frame, this,
                            aContainingBlockWidth, aContainingBlockHeight,
                            aBorder, aPadding);
   // If this is a reflow root, then set the computed width and
   // height equal to the available space
   if (nullptr == parentReflowState || mFlags.mDummyParentReflowState) {
     // XXXldb This doesn't mean what it used to!
     InitOffsets(aContainingBlockWidth,
                 VerticalOffsetPercentBasis(frame, aContainingBlockWidth,
                                            aContainingBlockHeight),
                 aFrameType, aBorder, aPadding);
     // Override mComputedMargin since reflow roots start from the
     // frame's boundary, which is inside the margin.
     ComputedPhysicalMargin().SizeTo(0, 0, 0, 0);
     ComputedPhysicalOffsets().SizeTo(0, 0, 0, 0);
     ComputedWidth() = AvailableWidth() - ComputedPhysicalBorderPadding().LeftRight();
     if (ComputedWidth() < 0)
       ComputedWidth() = 0;
     if (AvailableHeight() != NS_UNCONSTRAINEDSIZE) {
       ComputedHeight() = AvailableHeight() - ComputedPhysicalBorderPadding().TopBottom();
       if (ComputedHeight() < 0)
         ComputedHeight() = 0;
     } else {
       ComputedHeight() = NS_UNCONSTRAINEDSIZE;
     }
     ComputedMinWidth() = ComputedMinHeight() = 0;
     ComputedMaxWidth() = ComputedMaxHeight() = NS_UNCONSTRAINEDSIZE;
   } else {
     // Get the containing block reflow state
     const nsHTMLReflowState* cbrs = mCBReflowState;
     NS_ASSERTION(nullptr != cbrs, "no containing block");
     // If we weren't given a containing block width and height, then
     // compute one
     if (aContainingBlockWidth == -1) {
       ComputeContainingBlockRectangle(aPresContext, cbrs, aContainingBlockWidth,
                                       aContainingBlockHeight);
     }
     // See if the containing block height is based on the size of its
     // content
     nsIAtom* fType;
     if (NS_AUTOHEIGHT == aContainingBlockHeight) {
       // See if the containing block is a cell frame which needs
       // to use the mComputedHeight of the cell instead of what the cell block passed in.
       // XXX It seems like this could lead to bugs with min-height and friends
       if (cbrs->parentReflowState) {
         fType = cbrs->frame->GetType();
         if (IS_TABLE_CELL(fType)) {
           // use the cell's computed height
           aContainingBlockHeight = cbrs->ComputedHeight();
         }
       }
     }
     // XXX Might need to also pass the CB height (not width) for page boxes,
     // too, if we implement them.
     InitOffsets(aContainingBlockWidth,
                 VerticalOffsetPercentBasis(frame, aContainingBlockWidth,
                                            aContainingBlockHeight),
                 aFrameType, aBorder, aPadding);
     const nsStyleCoord &height = mStylePosition->mHeight;
     nsStyleUnit heightUnit = height.GetUnit();
     // Check for a percentage based height and a containing block height
     // that depends on the content height
     // XXX twiddling heightUnit doesn't help anymore
     // FIXME Shouldn't we fix that?
     if (height.HasPercent()) {
       if (NS_AUTOHEIGHT == aContainingBlockHeight) {
         // this if clause enables %-height on replaced inline frames,
         // such as images.  See bug 54119.  The else clause "heightUnit = eStyleUnit_Auto;"
         // used to be called exclusively.
         if (NS_FRAME_REPLACED(NS_CSS_FRAME_TYPE_INLINE) == mFrameType ||
             NS_FRAME_REPLACED_CONTAINS_BLOCK(
                 NS_CSS_FRAME_TYPE_INLINE) == mFrameType) {
           // Get the containing block reflow state
           NS_ASSERTION(nullptr != cbrs, "no containing block");
           // in quirks mode, get the cb height using the special quirk method
           if (eCompatibility_NavQuirks == aPresContext->CompatibilityMode()) {
             if (!IS_TABLE_CELL(fType)) {
               aContainingBlockHeight = CalcQuirkContainingBlockHeight(cbrs);
               if (aContainingBlockHeight == NS_AUTOHEIGHT) {
                 heightUnit = eStyleUnit_Auto;
               }
             }
             else {
               heightUnit = eStyleUnit_Auto;
             }
           }
           // in standard mode, use the cb height.  if it's "auto", as will be the case
           // by default in BODY, use auto height as per CSS2 spec.
           else
           {
             if (NS_AUTOHEIGHT != cbrs->ComputedHeight())
               aContainingBlockHeight = cbrs->ComputedHeight();
             else
               heightUnit = eStyleUnit_Auto;
           }
         }
         else {
           // default to interpreting the height like 'auto'
           heightUnit = eStyleUnit_Auto;
         }
       }
     }
     // Compute our offsets if the element is relatively positioned.  We need
     // the correct containing block width and height here, which is why we need
     // to do it after all the quirks-n-such above. (If the element is sticky
     // positioned, we need to wait until the scroll container knows its size,
     // so we compute offsets from StickyScrollContainer::UpdatePositions.)
     if (mStyleDisplay->IsRelativelyPositioned(frame) &&
         NS_STYLE_POSITION_RELATIVE == mStyleDisplay->mPosition) {
       uint8_t direction = NS_STYLE_DIRECTION_LTR;
       if (cbrs && NS_STYLE_DIRECTION_RTL == cbrs->mStyleVisibility->mDirection) {
         direction = NS_STYLE_DIRECTION_RTL;
       }
       ComputeRelativeOffsets(direction, frame, aContainingBlockWidth,
           aContainingBlockHeight, ComputedPhysicalOffsets());
     } else {
       // Initialize offsets to 0
       ComputedPhysicalOffsets().SizeTo(0, 0, 0, 0);
     }
     // Calculate the computed values for min and max properties.  Note that
     // this MUST come after we've computed our border and padding.
     ComputeMinMaxValues(aContainingBlockWidth, aContainingBlockHeight, cbrs);
     // Calculate the computed width and height. This varies by frame type
     if (NS_CSS_FRAME_TYPE_INTERNAL_TABLE == mFrameType) {
       // Internal table elements. The rules vary depending on the type.
       // Calculate the computed width
       bool rowOrRowGroup = false;
       const nsStyleCoord &width = mStylePosition->mWidth;
       nsStyleUnit widthUnit = width.GetUnit();
       if ((NS_STYLE_DISPLAY_TABLE_ROW == mStyleDisplay->mDisplay) ||
           (NS_STYLE_DISPLAY_TABLE_ROW_GROUP == mStyleDisplay->mDisplay)) {
         // 'width' property doesn't apply to table rows and row groups
         widthUnit = eStyleUnit_Auto;
         rowOrRowGroup = true;
       }
       // calc() with percentages acts like auto on internal table elements
       if (eStyleUnit_Auto == widthUnit ||
           (width.IsCalcUnit() && width.CalcHasPercent())) {
         ComputedWidth() = AvailableWidth();
         if ((ComputedWidth() != NS_UNCONSTRAINEDSIZE) && !rowOrRowGroup){
           // Internal table elements don't have margins. Only tables and
           // cells have border and padding
           ComputedWidth() -= ComputedPhysicalBorderPadding().left +
             ComputedPhysicalBorderPadding().right;
           if (ComputedWidth() < 0)
             ComputedWidth() = 0;
         }
         NS_ASSERTION(ComputedWidth() >= 0, "Bogus computed width");
       } else {
         NS_ASSERTION(widthUnit == mStylePosition->mWidth.GetUnit(),
                      "unexpected width unit change");
         ComputedWidth() = ComputeWidthValue(aContainingBlockWidth,
                                            mStylePosition->mBoxSizing,
                                            mStylePosition->mWidth);
       }
       // Calculate the computed height
       if ((NS_STYLE_DISPLAY_TABLE_COLUMN == mStyleDisplay->mDisplay) ||
           (NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP == mStyleDisplay->mDisplay)) {
         // 'height' property doesn't apply to table columns and column groups
         heightUnit = eStyleUnit_Auto;
       }
       // calc() with percentages acts like 'auto' on internal table elements
       if (eStyleUnit_Auto == heightUnit ||
           (height.IsCalcUnit() && height.CalcHasPercent())) {
         ComputedHeight() = NS_AUTOHEIGHT;
       } else {
         NS_ASSERTION(heightUnit == mStylePosition->mHeight.GetUnit(),
                      "unexpected height unit change");
         ComputedHeight() = ComputeHeightValue(aContainingBlockHeight,
                                              mStylePosition->mBoxSizing,
                                              mStylePosition->mHeight);
       }
       // Doesn't apply to table elements
       ComputedMinWidth() = ComputedMinHeight() = 0;
       ComputedMaxWidth() = ComputedMaxHeight() = NS_UNCONSTRAINEDSIZE;
     } else if (NS_FRAME_GET_TYPE(mFrameType) == NS_CSS_FRAME_TYPE_ABSOLUTE) {
       // XXX not sure if this belongs here or somewhere else - cwk
       InitAbsoluteConstraints(aPresContext, cbrs, aContainingBlockWidth,
                               aContainingBlockHeight, aFrameType);
     } else {
       AutoMaybeDisableFontInflation an(frame);
       bool isBlock = NS_CSS_FRAME_TYPE_BLOCK == NS_FRAME_GET_TYPE(mFrameType);
       uint32_t computeSizeFlags = isBlock ? 0 : nsIFrame::eShrinkWrap;
       // Make sure legend frames with display:block and width:auto still
       // shrink-wrap.
       if (isBlock &&
           ((aFrameType == nsGkAtoms::legendFrame &&
             frame->StyleContext()->GetPseudo() != nsCSSAnonBoxes::scrolledContent) ||
            (aFrameType == nsGkAtoms::scrollFrame &&
             frame->GetContentInsertionFrame()->GetType() == nsGkAtoms::legendFrame))) {
         computeSizeFlags |= nsIFrame::eShrinkWrap;
       }
       const nsFlexContainerFrame* flexContainerFrame = GetFlexContainer(frame);
       if (flexContainerFrame) {
         computeSizeFlags |= nsIFrame::eShrinkWrap;
         // If we're inside of a flex container that needs to measure our
         // auto height, pass that information along to ComputeSize().
         if (mFlags.mIsFlexContainerMeasuringHeight) {
           computeSizeFlags |= nsIFrame::eUseAutoHeight;
         }
       } else {
         MOZ_ASSERT(!mFlags.mIsFlexContainerMeasuringHeight,
                    "We're not in a flex container, so the flag "
                    "'mIsFlexContainerMeasuringHeight' shouldn't be set");
       }
       nsSize size =
         frame->ComputeSize(rendContext,
                            nsSize(aContainingBlockWidth,
                                   aContainingBlockHeight),
                            AvailableWidth(),
                            nsSize(ComputedPhysicalMargin().LeftRight(),
                                   ComputedPhysicalMargin().TopBottom()),
                            nsSize(ComputedPhysicalBorderPadding().LeftRight() -
                                     ComputedPhysicalPadding().LeftRight(),
                                   ComputedPhysicalBorderPadding().TopBottom() -
                                     ComputedPhysicalPadding().TopBottom()),
                            nsSize(ComputedPhysicalPadding().LeftRight(),
                                   ComputedPhysicalPadding().TopBottom()),
                            computeSizeFlags);
       ComputedWidth() = size.width;
       ComputedHeight() = size.height;
       NS_ASSERTION(ComputedWidth() >= 0, "Bogus width");
       NS_ASSERTION(ComputedHeight() == NS_UNCONSTRAINEDSIZE ||
                    ComputedHeight() >= 0, "Bogus height");
       // Exclude inline tables and flex items from the block margin calculations
       if (isBlock &&
           !IsSideCaption(frame, mStyleDisplay) &&
           mStyleDisplay->mDisplay != NS_STYLE_DISPLAY_INLINE_TABLE &&
           !flexContainerFrame) {
         CalculateBlockSideMargins(AvailableWidth(), ComputedWidth(), aFrameType);
       }
     }
   }
 }
 static void
 UpdateProp(FrameProperties& aProps,
            const FramePropertyDescriptor* aProperty,
            bool aNeeded,
            nsMargin& aNewValue)
 {
   if (aNeeded) {
     nsMargin* propValue = static_cast<nsMargin*>(aProps.Get(aProperty));
     if (propValue) {
       *propValue = aNewValue;
     } else {
       aProps.Set(aProperty, new nsMargin(aNewValue));
     }
   } else {
     aProps.Delete(aProperty);
   }
 }
 void
 nsCSSOffsetState::InitOffsets(nscoord aHorizontalPercentBasis,
                               nscoord aVerticalPercentBasis,
                               nsIAtom* aFrameType,
                               const nsMargin *aBorder,
                               const nsMargin *aPadding)
 {
   DISPLAY_INIT_OFFSETS(frame, this,
                        aHorizontalPercentBasis,
                        aVerticalPercentBasis,
                        aBorder, aPadding);
   // Since we are in reflow, we don't need to store these properties anymore
   // unless they are dependent on width, in which case we store the new value.
   nsPresContext *presContext = frame->PresContext();
   FrameProperties props(presContext->PropertyTable(), frame);
   props.Delete(nsIFrame::UsedBorderProperty());
   // Compute margins from the specified margin style information. These
   // become the default computed values, and may be adjusted below
   // XXX fix to provide 0,0 for the top&bottom margins for
   // inline-non-replaced elements
   bool needMarginProp = ComputeMargin(aHorizontalPercentBasis,
                                       aVerticalPercentBasis);
   // XXX We need to include 'auto' horizontal margins in this too!
   // ... but if we did that, we'd need to fix nsFrame::GetUsedMargin
   // to use it even when the margins are all zero (since sometimes
   // they get treated as auto)
   ::UpdateProp(props, nsIFrame::UsedMarginProperty(), needMarginProp,
                ComputedPhysicalMargin());
   const nsStyleDisplay *disp = frame->StyleDisplay();
   bool isThemed = frame->IsThemed(disp);
   bool needPaddingProp;
   nsIntMargin widget;
   if (isThemed &&
       presContext->GetTheme()->GetWidgetPadding(presContext->DeviceContext(),
                                                 frame, disp->mAppearance,
                                                 &widget)) {
     ComputedPhysicalPadding().top = presContext->DevPixelsToAppUnits(widget.top);
     ComputedPhysicalPadding().right = presContext->DevPixelsToAppUnits(widget.right);
     ComputedPhysicalPadding().bottom = presContext->DevPixelsToAppUnits(widget.bottom);
     ComputedPhysicalPadding().left = presContext->DevPixelsToAppUnits(widget.left);
     needPaddingProp = false;
   }
   else if (frame->IsSVGText()) {
     ComputedPhysicalPadding().SizeTo(0, 0, 0, 0);
     needPaddingProp = false;
   }
   else if (aPadding) { // padding is an input arg
     ComputedPhysicalPadding() = *aPadding;
     needPaddingProp = frame->StylePadding()->IsWidthDependent() ||
 	  (frame->GetStateBits() & NS_FRAME_REFLOW_ROOT);
   }
   else {
     needPaddingProp = ComputePadding(aHorizontalPercentBasis,
                                      aVerticalPercentBasis, aFrameType);
   }
   if (isThemed) {
     nsIntMargin widget;
     presContext->GetTheme()->GetWidgetBorder(presContext->DeviceContext(),
                                              frame, disp->mAppearance,
                                              &widget);
     ComputedPhysicalBorderPadding().top =
       presContext->DevPixelsToAppUnits(widget.top);
     ComputedPhysicalBorderPadding().right =
       presContext->DevPixelsToAppUnits(widget.right);
     ComputedPhysicalBorderPadding().bottom =
       presContext->DevPixelsToAppUnits(widget.bottom);
     ComputedPhysicalBorderPadding().left =
       presContext->DevPixelsToAppUnits(widget.left);
   }
   else if (frame->IsSVGText()) {
     ComputedPhysicalBorderPadding().SizeTo(0, 0, 0, 0);
   }
   else if (aBorder) {  // border is an input arg
     ComputedPhysicalBorderPadding() = *aBorder;
   }
   else {
     ComputedPhysicalBorderPadding() = frame->StyleBorder()->GetComputedBorder();
   }
   ComputedPhysicalBorderPadding() += ComputedPhysicalPadding();
   if (aFrameType == nsGkAtoms::tableFrame) {
     nsTableFrame *tableFrame = static_cast<nsTableFrame*>(frame);
     if (tableFrame->IsBorderCollapse()) {
       // border-collapsed tables don't use any of their padding, and
       // only part of their border.  We need to do this here before we
       // try to do anything like handling 'auto' widths,
       // 'box-sizing', or 'auto' margins.
       ComputedPhysicalPadding().SizeTo(0,0,0,0);
       ComputedPhysicalBorderPadding() = tableFrame->GetIncludedOuterBCBorder();
     }
     // The margin is inherited to the outer table frame via
     // the ::-moz-table-outer rule in ua.css.
     ComputedPhysicalMargin().SizeTo(0, 0, 0, 0);
   } else if (aFrameType == nsGkAtoms::scrollbarFrame) {
     // scrollbars may have had their width or height smashed to zero
     // by the associated scrollframe, in which case we must not report
     // any padding or border.
     nsSize size(frame->GetSize());
     if (size.width == 0 || size.height == 0) {
       ComputedPhysicalPadding().SizeTo(0,0,0,0);
       ComputedPhysicalBorderPadding().SizeTo(0,0,0,0);
     }
   }
   ::UpdateProp(props, nsIFrame::UsedPaddingProperty(), needPaddingProp,
                ComputedPhysicalPadding());
 }
 // This code enforces section 10.3.3 of the CSS2 spec for this formula:
 //
 // 'margin-left' + 'border-left-width' + 'padding-left' + 'width' +
 //   'padding-right' + 'border-right-width' + 'margin-right'
 //   = width of containing block
 //
 // Note: the width unit is not auto when this is called
 void
 nsHTMLReflowState::CalculateBlockSideMargins(nscoord aAvailWidth,
                                              nscoord aComputedWidth,
                                              nsIAtom* aFrameType)
 {
   NS_WARN_IF_FALSE(NS_UNCONSTRAINEDSIZE != aComputedWidth &&
                    NS_UNCONSTRAINEDSIZE != aAvailWidth,
                    "have unconstrained width; this should only result from "
                    "very large sizes, not attempts at intrinsic width "
                    "calculation");
   nscoord sum = ComputedPhysicalMargin().left + ComputedPhysicalBorderPadding().left +
     aComputedWidth + ComputedPhysicalBorderPadding().right + ComputedPhysicalMargin().right;
   if (sum == aAvailWidth)
     // The sum is already correct
     return;
   // Determine the left and right margin values. The width value
   // remains constant while we do this.
   // Calculate how much space is available for margins
   nscoord availMarginSpace = aAvailWidth - sum;
   // If the available margin space is negative, then don't follow the
   // usual overconstraint rules.
   if (availMarginSpace < 0) {
     if (mCBReflowState &&
         mCBReflowState->mStyleVisibility->mDirection == NS_STYLE_DIRECTION_RTL) {
       ComputedPhysicalMargin().left += availMarginSpace;
     } else {
       ComputedPhysicalMargin().right += availMarginSpace;
     }
     return;
   }
   // The css2 spec clearly defines how block elements should behave
   // in section 10.3.3.
   bool isAutoLeftMargin =
     eStyleUnit_Auto == mStyleMargin->mMargin.GetLeftUnit();
   bool isAutoRightMargin =
     eStyleUnit_Auto == mStyleMargin->mMargin.GetRightUnit();
   if (!isAutoLeftMargin && !isAutoRightMargin) {
     // Neither margin is 'auto' so we're over constrained. Use the
     // 'direction' property of the parent to tell which margin to
     // ignore
     // First check if there is an HTML alignment that we should honor
     const nsHTMLReflowState* prs = parentReflowState;
     if (aFrameType == nsGkAtoms::tableFrame) {
       NS_ASSERTION(prs->frame->GetType() == nsGkAtoms::tableOuterFrame,
                    "table not inside outer table");
       // Center the table within the outer table based on the alignment
       // of the outer table's parent.
       prs = prs->parentReflowState;
     }
     if (prs &&
         (prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_LEFT ||
          prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_CENTER ||
          prs->mStyleText->mTextAlign == NS_STYLE_TEXT_ALIGN_MOZ_RIGHT)) {
       isAutoLeftMargin =
         prs->mStyleText->mTextAlign != NS_STYLE_TEXT_ALIGN_MOZ_LEFT;
       isAutoRightMargin =
         prs->mStyleText->mTextAlign != NS_STYLE_TEXT_ALIGN_MOZ_RIGHT;
     }
     // Otherwise apply the CSS rules, and ignore one margin by forcing
     // it to 'auto', depending on 'direction'.
     else if (mCBReflowState &&
              NS_STYLE_DIRECTION_RTL == mCBReflowState->mStyleVisibility->mDirection) {
       isAutoLeftMargin = true;
     }
     else {
       isAutoRightMargin = true;
     }
   }
   // Logic which is common to blocks and tables
   // The computed margins need not be zero because the 'auto' could come from
   // overconstraint or from HTML alignment so values need to be accumulated
   if (isAutoLeftMargin) {
     if (isAutoRightMargin) {
       // Both margins are 'auto' so the computed addition should be equal
       nscoord forLeft = availMarginSpace / 2;
       ComputedPhysicalMargin().left  += forLeft;
       ComputedPhysicalMargin().right += availMarginSpace - forLeft;
     } else {
       ComputedPhysicalMargin().left += availMarginSpace;
     }
   } else if (isAutoRightMargin) {
     ComputedPhysicalMargin().right += availMarginSpace;
   }
 }
 #define NORMAL_LINE_HEIGHT_FACTOR 1.2f    // in term of emHeight
 // For "normal" we use the font's normal line height (em height + leading).
 // If both internal leading and  external leading specified by font itself
 // are zeros, we should compensate this by creating extra (external) leading
 // in eCompensateLeading mode. This is necessary because without this
 // compensation, normal line height might looks too tight.
 // For risk management, we use preference to control the behavior, and
 // eNoExternalLeading is the old behavior.
 static nscoord
 GetNormalLineHeight(nsFontMetrics* aFontMetrics)
 {
   NS_PRECONDITION(nullptr != aFontMetrics, "no font metrics");
   nscoord normalLineHeight;
   nscoord externalLeading = aFontMetrics->ExternalLeading();
   nscoord internalLeading = aFontMetrics->InternalLeading();
   nscoord emHeight = aFontMetrics->EmHeight();
   switch (GetNormalLineHeightCalcControl()) {
   case eIncludeExternalLeading:
     normalLineHeight = emHeight+ internalLeading + externalLeading;
     break;
   case eCompensateLeading:
     if (!internalLeading && !externalLeading)
       normalLineHeight = NSToCoordRound(emHeight * NORMAL_LINE_HEIGHT_FACTOR);
     else
       normalLineHeight = emHeight+ internalLeading + externalLeading;
     break;
   default:
     //case eNoExternalLeading:
     normalLineHeight = emHeight + internalLeading;
   }
   return normalLineHeight;
 }
 static inline nscoord
 ComputeLineHeight(nsStyleContext* aStyleContext,
                   nscoord aBlockHeight,
                   float aFontSizeInflation)
 {
   const nsStyleCoord& lhCoord = aStyleContext->StyleText()->mLineHeight;
   if (lhCoord.GetUnit() == eStyleUnit_Coord) {
     nscoord result = lhCoord.GetCoordValue();
     if (aFontSizeInflation != 1.0f) {
       result = NSToCoordRound(result * aFontSizeInflation);
     }
     return result;
   }
   if (lhCoord.GetUnit() == eStyleUnit_Factor)
     // For factor units the computed value of the line-height property
     // is found by multiplying the factor by the font's computed size
     // (adjusted for min-size prefs and text zoom).
     return NSToCoordRound(lhCoord.GetFactorValue() * aFontSizeInflation *
                           aStyleContext->StyleFont()->mFont.size);
   NS_ASSERTION(lhCoord.GetUnit() == eStyleUnit_Normal ||
                lhCoord.GetUnit() == eStyleUnit_Enumerated,
                "bad line-height unit");
   if (lhCoord.GetUnit() == eStyleUnit_Enumerated) {
     NS_ASSERTION(lhCoord.GetIntValue() == NS_STYLE_LINE_HEIGHT_BLOCK_HEIGHT,
                  "bad line-height value");
     if (aBlockHeight != NS_AUTOHEIGHT) {
       return aBlockHeight;
     }
   }
   nsRefPtr<nsFontMetrics> fm;
   nsLayoutUtils::GetFontMetricsForStyleContext(aStyleContext,
                                                getter_AddRefs(fm),
                                                aFontSizeInflation);
   return GetNormalLineHeight(fm);
 }
 nscoord
 nsHTMLReflowState::CalcLineHeight() const
 {
   nscoord blockHeight =
     nsLayoutUtils::IsNonWrapperBlock(frame) ? ComputedHeight() :
     (mCBReflowState ? mCBReflowState->ComputedHeight() : NS_AUTOHEIGHT);
   return CalcLineHeight(frame->GetContent(), frame->StyleContext(), blockHeight,
                         nsLayoutUtils::FontSizeInflationFor(frame));
 }
 /* static */ nscoord
 nsHTMLReflowState::CalcLineHeight(nsIContent* aContent,
                                   nsStyleContext* aStyleContext,
                                   nscoord aBlockHeight,
                                   float aFontSizeInflation)
 {
   NS_PRECONDITION(aStyleContext, "Must have a style context");
   nscoord lineHeight =
     ComputeLineHeight(aStyleContext, aBlockHeight, aFontSizeInflation);
   NS_ASSERTION(lineHeight >= 0, "ComputeLineHeight screwed up");
   HTMLInputElement* input = HTMLInputElement::FromContentOrNull(aContent);
   if (input && input->IsSingleLineTextControl()) {
     // For Web-compatibility, single-line text input elements cannot
     // have a line-height smaller than one.
     nscoord lineHeightOne =
       aFontSizeInflation * aStyleContext->StyleFont()->mFont.size;
     if (lineHeight < lineHeightOne) {
       lineHeight = lineHeightOne;
     }
   }
   return lineHeight;
 }
 bool
 nsCSSOffsetState::ComputeMargin(nscoord aHorizontalPercentBasis,
                                 nscoord aVerticalPercentBasis)
 {
   // SVG text frames have no margin.
   if (frame->IsSVGText()) {
     return false;
   }
   // If style style can provide us the margin directly, then use it.
   const nsStyleMargin *styleMargin = frame->StyleMargin();
   bool isCBDependent = !styleMargin->GetMargin(ComputedPhysicalMargin());
   if (isCBDependent) {
     // We have to compute the value
     ComputedPhysicalMargin().left = nsLayoutUtils::
       ComputeCBDependentValue(aHorizontalPercentBasis,
                               styleMargin->mMargin.GetLeft());
     ComputedPhysicalMargin().right = nsLayoutUtils::
       ComputeCBDependentValue(aHorizontalPercentBasis,
                               styleMargin->mMargin.GetRight());
     ComputedPhysicalMargin().top = nsLayoutUtils::
       ComputeCBDependentValue(aVerticalPercentBasis,
                               styleMargin->mMargin.GetTop());
     ComputedPhysicalMargin().bottom = nsLayoutUtils::
       ComputeCBDependentValue(aVerticalPercentBasis,
                               styleMargin->mMargin.GetBottom());
   }
   nscoord marginAdjustment = FontSizeInflationListMarginAdjustment(frame);
   if (marginAdjustment > 0) {
     const nsStyleVisibility* visibility = frame->StyleVisibility();
     if (visibility->mDirection == NS_STYLE_DIRECTION_RTL) {
       ComputedPhysicalMargin().right = ComputedPhysicalMargin().right + marginAdjustment;
     } else {
       ComputedPhysicalMargin().left = ComputedPhysicalMargin().left + marginAdjustment;
     }
   }
   return isCBDependent;
 }
 bool
 nsCSSOffsetState::ComputePadding(nscoord aHorizontalPercentBasis,
                                  nscoord aVerticalPercentBasis,
                                  nsIAtom* aFrameType)
 {
   // If style can provide us the padding directly, then use it.
   const nsStylePadding *stylePadding = frame->StylePadding();
   bool isCBDependent = !stylePadding->GetPadding(ComputedPhysicalPadding());
   // a table row/col group, row/col doesn't have padding
   // XXXldb Neither do border-collapse tables.
   if (nsGkAtoms::tableRowGroupFrame == aFrameType ||
       nsGkAtoms::tableColGroupFrame == aFrameType ||
       nsGkAtoms::tableRowFrame      == aFrameType ||
       nsGkAtoms::tableColFrame      == aFrameType) {
     ComputedPhysicalPadding().SizeTo(0,0,0,0);
   }
   else if (isCBDependent) {
     // We have to compute the value
     // clamp negative calc() results to 0
     ComputedPhysicalPadding().left = std::max(0, nsLayoutUtils::
       ComputeCBDependentValue(aHorizontalPercentBasis,
                               stylePadding->mPadding.GetLeft()));
     ComputedPhysicalPadding().right = std::max(0, nsLayoutUtils::
       ComputeCBDependentValue(aHorizontalPercentBasis,
                               stylePadding->mPadding.GetRight()));
     ComputedPhysicalPadding().top = std::max(0, nsLayoutUtils::
       ComputeCBDependentValue(aVerticalPercentBasis,
                               stylePadding->mPadding.GetTop()));
     ComputedPhysicalPadding().bottom = std::max(0, nsLayoutUtils::
       ComputeCBDependentValue(aVerticalPercentBasis,
                               stylePadding->mPadding.GetBottom()));
   }
   return isCBDependent;
 }
 void
 nsHTMLReflowState::ComputeMinMaxValues(nscoord aContainingBlockWidth,
                                        nscoord aContainingBlockHeight,
                                        const nsHTMLReflowState* aContainingBlockRS)
 {
   ComputedMinWidth() = ComputeWidthValue(aContainingBlockWidth,
                                         mStylePosition->mBoxSizing,
                                         mStylePosition->mMinWidth);
   if (eStyleUnit_None == mStylePosition->mMaxWidth.GetUnit()) {
     // Specified value of 'none'
     ComputedMaxWidth() = NS_UNCONSTRAINEDSIZE;  // no limit
   } else {
     ComputedMaxWidth() = ComputeWidthValue(aContainingBlockWidth,
                                           mStylePosition->mBoxSizing,
                                           mStylePosition->mMaxWidth);
   }
   // If the computed value of 'min-width' is greater than the value of
   // 'max-width', 'max-width' is set to the value of 'min-width'
   if (ComputedMinWidth() > ComputedMaxWidth()) {
     ComputedMaxWidth() = ComputedMinWidth();
   }
   // Check for percentage based values and a containing block height that
   // depends on the content height. Treat them like 'auto'
   // Likewise, check for calc() with percentages on internal table elements;
   // that's treated as 'auto' too.
   // Likewise, if we're a child of a flex container who's measuring our
   // intrinsic height, then we want to disregard our min-height.
   const nsStyleCoord &minHeight = mStylePosition->mMinHeight;
   if ((NS_AUTOHEIGHT == aContainingBlockHeight &&
        minHeight.HasPercent()) ||
       (mFrameType == NS_CSS_FRAME_TYPE_INTERNAL_TABLE &&
        minHeight.IsCalcUnit() && minHeight.CalcHasPercent()) ||
       mFlags.mIsFlexContainerMeasuringHeight) {
     ComputedMinHeight() = 0;
   } else {
     ComputedMinHeight() = ComputeHeightValue(aContainingBlockHeight,
                                             mStylePosition->mBoxSizing,
                                             minHeight);
   }
   const nsStyleCoord &maxHeight = mStylePosition->mMaxHeight;
   nsStyleUnit maxHeightUnit = maxHeight.GetUnit();
   if (eStyleUnit_None == maxHeightUnit) {
     // Specified value of 'none'
     ComputedMaxHeight() = NS_UNCONSTRAINEDSIZE;  // no limit
   } else {
     // Check for percentage based values and a containing block height that
     // depends on the content height. Treat them like 'none'
     // Likewise, check for calc() with percentages on internal table elements;
     // that's treated as 'auto' too.
     // Likewise, if we're a child of a flex container who's measuring our
     // intrinsic height, then we want to disregard our max-height.
     if ((NS_AUTOHEIGHT == aContainingBlockHeight &&
          maxHeight.HasPercent()) ||
         (mFrameType == NS_CSS_FRAME_TYPE_INTERNAL_TABLE &&
          maxHeight.IsCalcUnit() && maxHeight.CalcHasPercent()) ||
         mFlags.mIsFlexContainerMeasuringHeight) {
       ComputedMaxHeight() = NS_UNCONSTRAINEDSIZE;
     } else {
       ComputedMaxHeight() = ComputeHeightValue(aContainingBlockHeight,
                                               mStylePosition->mBoxSizing,
                                               maxHeight);
     }
   }
   // If the computed value of 'min-height' is greater than the value of
   // 'max-height', 'max-height' is set to the value of 'min-height'
   if (ComputedMinHeight() > ComputedMaxHeight()) {
     ComputedMaxHeight() = ComputedMinHeight();
   }
 }
 void
 nsHTMLReflowState::SetTruncated(const nsHTMLReflowMetrics& aMetrics,
                                 nsReflowStatus* aStatus) const
 {
   if (AvailableHeight() != NS_UNCONSTRAINEDSIZE &&
       AvailableHeight() < aMetrics.Height() &&
       !mFlags.mIsTopOfPage) {
     *aStatus |= NS_FRAME_TRUNCATED;
   } else {
     *aStatus &= ~NS_FRAME_TRUNCATED;
   }
 }
 bool
 nsHTMLReflowState::IsFloating() const
 {
   return mStyleDisplay->IsFloating(frame);
 }
 uint8_t
 nsHTMLReflowState::GetDisplay() const
 {
   return mStyleDisplay->GetDisplay(frame);
 }

The Tor Browser / annotate

layout/generic/nsHTMLReflowState.cpp@6474c204b198 (annotated)

layout/generic/nsHTMLReflowState.cpp