layout/mathml/nsMathMLContainerFrame.cpp
author Ryan VanderMeulen <ryanvm@gmail.com>
Mon, 29 Jul 2013 15:19:34 -0400
changeset 152713 a59ad3157c17f3df0a132979f428c65211e4ce23
parent 152687 b67a72618c669e643e625ab6dbfddd920d78d95b
child 153578 dc5bce83d80164e89844395c15ee1083b7391acb
permissions -rw-r--r--
Backed out 6 changesets (bug 827713) for reftest failures. Backed out changeset 014cc3de08fb (bug 827713) Backed out changeset 4113172193aa (bug 827713) Backed out changeset 27a5c8dd5ff7 (bug 827713) Backed out changeset 6448c7e05f11 (bug 827713) Backed out changeset b67a72618c66 (bug 827713) Backed out changeset 1279664e0d41 (bug 827713)

/* -*- 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/. */

#include "nsCOMPtr.h"
#include "nsHTMLParts.h"
#include "nsFrame.h"
#include "nsPresContext.h"
#include "nsIPresShell.h"
#include "nsCSSAnonBoxes.h"
#include "nsStyleContext.h"
#include "nsStyleConsts.h"
#include "nsINameSpaceManager.h"
#include "nsRenderingContext.h"

#include "nsIDOMMutationEvent.h"
#include "nsFrameManager.h"
#include "nsStyleChangeList.h"

#include "nsGkAtoms.h"
#include "nsMathMLParts.h"
#include "nsMathMLContainerFrame.h"
#include "nsAutoPtr.h"
#include "nsStyleSet.h"
#include "nsDisplayList.h"
#include "nsCSSFrameConstructor.h"
#include "nsIReflowCallback.h"
#include "mozilla/Likely.h"
#include "nsIScriptError.h"
#include "nsContentUtils.h"

using namespace mozilla;

//
// nsMathMLContainerFrame implementation
//

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLContainerFrame)

NS_QUERYFRAME_HEAD(nsMathMLContainerFrame)
  NS_QUERYFRAME_ENTRY(nsIMathMLFrame)
NS_QUERYFRAME_TAIL_INHERITING(nsContainerFrame)

// =============================================================================

// error handlers
// provide a feedback to the user when a frame with bad markup can not be rendered
nsresult
nsMathMLContainerFrame::ReflowError(nsRenderingContext& aRenderingContext,
                                    nsHTMLReflowMetrics& aDesiredSize)
{
  // clear all other flags and record that there is an error with this frame
  mEmbellishData.flags = 0;
  mPresentationData.flags = NS_MATHML_ERROR;

  ///////////////
  // Set font
  nsRefPtr<nsFontMetrics> fm;
  nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fm));
  aRenderingContext.SetFont(fm);

  // bounding metrics
  nsAutoString errorMsg; errorMsg.AssignLiteral("invalid-markup");
  mBoundingMetrics =
    aRenderingContext.GetBoundingMetrics(errorMsg.get(), errorMsg.Length());

  // reflow metrics
  aDesiredSize.ascent = fm->MaxAscent();
  nscoord descent = fm->MaxDescent();
  aDesiredSize.height = aDesiredSize.ascent + descent;
  aDesiredSize.width = mBoundingMetrics.width;

  // Also return our bounding metrics
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

  return NS_OK;
}

class nsDisplayMathMLError : public nsDisplayItem {
public:
  nsDisplayMathMLError(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame)
    : nsDisplayItem(aBuilder, aFrame) {
    MOZ_COUNT_CTOR(nsDisplayMathMLError);
  }
#ifdef NS_BUILD_REFCNT_LOGGING
  virtual ~nsDisplayMathMLError() {
    MOZ_COUNT_DTOR(nsDisplayMathMLError);
  }
#endif

  virtual void Paint(nsDisplayListBuilder* aBuilder,
                     nsRenderingContext* aCtx);
  NS_DISPLAY_DECL_NAME("MathMLError", TYPE_MATHML_ERROR)
};

void nsDisplayMathMLError::Paint(nsDisplayListBuilder* aBuilder,
                                 nsRenderingContext* aCtx)
{
  // Set color and font ...
  nsRefPtr<nsFontMetrics> fm;
  nsLayoutUtils::GetFontMetricsForFrame(mFrame, getter_AddRefs(fm));
  aCtx->SetFont(fm);

  nsPoint pt = ToReferenceFrame();
  aCtx->SetColor(NS_RGB(255,0,0));
  aCtx->FillRect(nsRect(pt, mFrame->GetSize()));
  aCtx->SetColor(NS_RGB(255,255,255));

  nscoord ascent = aCtx->FontMetrics()->MaxAscent();

  NS_NAMED_LITERAL_STRING(errorMsg, "invalid-markup");
  aCtx->DrawString(errorMsg.get(), uint32_t(errorMsg.Length()),
                   pt.x, pt.y+ascent);
}

/* /////////////
 * nsIMathMLFrame - support methods for stretchy elements
 * =============================================================================
 */

static bool
IsForeignChild(const nsIFrame* aFrame)
{
  // This counts nsMathMLmathBlockFrame as a foreign child, because it
  // uses block reflow
  return !(aFrame->IsFrameOfType(nsIFrame::eMathML)) ||
    aFrame->GetType() == nsGkAtoms::blockFrame;
}

static void
DestroyHTMLReflowMetrics(void *aPropertyValue)
{
  delete static_cast<nsHTMLReflowMetrics*>(aPropertyValue);
}

NS_DECLARE_FRAME_PROPERTY(HTMLReflowMetricsProperty, DestroyHTMLReflowMetrics)

/* static */ void
nsMathMLContainerFrame::SaveReflowAndBoundingMetricsFor(nsIFrame*                  aFrame,
                                                        const nsHTMLReflowMetrics& aReflowMetrics,
                                                        const nsBoundingMetrics&   aBoundingMetrics)
{
  nsHTMLReflowMetrics *metrics = new nsHTMLReflowMetrics(aReflowMetrics);
  metrics->mBoundingMetrics = aBoundingMetrics;
  aFrame->Properties().Set(HTMLReflowMetricsProperty(), metrics);
}

// helper method to facilitate getting the reflow and bounding metrics
/* static */ void
nsMathMLContainerFrame::GetReflowAndBoundingMetricsFor(nsIFrame*            aFrame,
                                                       nsHTMLReflowMetrics& aReflowMetrics,
                                                       nsBoundingMetrics&   aBoundingMetrics,
                                                       eMathMLFrameType*    aMathMLFrameType)
{
  NS_PRECONDITION(aFrame, "null arg");

  nsHTMLReflowMetrics *metrics = static_cast<nsHTMLReflowMetrics*>
    (aFrame->Properties().Get(HTMLReflowMetricsProperty()));

  // IMPORTANT: This function is only meant to be called in Place() methods
  // where it is assumed that SaveReflowAndBoundingMetricsFor has recorded the
  // information.
  NS_ASSERTION(metrics, "Didn't SaveReflowAndBoundingMetricsFor frame!");
  if (metrics) {
    aReflowMetrics = *metrics;
    aBoundingMetrics = metrics->mBoundingMetrics;
  }

  if (aMathMLFrameType) {
    if (!IsForeignChild(aFrame)) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(aFrame);
      if (mathMLFrame) {
        *aMathMLFrameType = mathMLFrame->GetMathMLFrameType();
        return;
      }
    }
    *aMathMLFrameType = eMathMLFrameType_UNKNOWN;
  }

}

void
nsMathMLContainerFrame::ClearSavedChildMetrics()
{
  nsIFrame* childFrame = mFrames.FirstChild();
  FramePropertyTable* props = PresContext()->PropertyTable();
  while (childFrame) {
    props->Delete(childFrame, HTMLReflowMetricsProperty());
    childFrame = childFrame->GetNextSibling();
  }
}

// helper to get the preferred size that a container frame should use to fire
// the stretch on its stretchy child frames.
void
nsMathMLContainerFrame::GetPreferredStretchSize(nsRenderingContext& aRenderingContext,
                                                uint32_t             aOptions,
                                                nsStretchDirection   aStretchDirection,
                                                nsBoundingMetrics&   aPreferredStretchSize)
{
  if (aOptions & STRETCH_CONSIDER_ACTUAL_SIZE) {
    // when our actual size is ok, just use it
    aPreferredStretchSize = mBoundingMetrics;
  }
  else if (aOptions & STRETCH_CONSIDER_EMBELLISHMENTS) {
    // compute our up-to-date size using Place()
    nsHTMLReflowMetrics metrics;
    Place(aRenderingContext, false, metrics);
    aPreferredStretchSize = metrics.mBoundingMetrics;
  }
  else {
    // compute a size that doesn't include embellishements
    bool stretchAll =
      NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags) ||
      NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(mPresentationData.flags);
    NS_ASSERTION(NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags) ||
                 stretchAll,
                 "invalid call to GetPreferredStretchSize");
    bool firstTime = true;
    nsBoundingMetrics bm, bmChild;
    nsIFrame* childFrame =
      stretchAll ? GetFirstPrincipalChild() : mPresentationData.baseFrame;
    while (childFrame) {
      // initializations in case this child happens not to be a MathML frame
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
      if (mathMLFrame) {
        nsEmbellishData embellishData;
        nsPresentationData presentationData;
        mathMLFrame->GetEmbellishData(embellishData);
        mathMLFrame->GetPresentationData(presentationData);
        if (NS_MATHML_IS_EMBELLISH_OPERATOR(embellishData.flags) &&
            embellishData.direction == aStretchDirection &&
            presentationData.baseFrame) {
          // embellishements are not included, only consider the inner first child itself
          // XXXkt Does that mean the core descendent frame should be used
          // instead of the base child?
          nsIMathMLFrame* mathMLchildFrame = do_QueryFrame(presentationData.baseFrame);
          if (mathMLchildFrame) {
            mathMLFrame = mathMLchildFrame;
          }
        }
        mathMLFrame->GetBoundingMetrics(bmChild);
      }
      else {
        nsHTMLReflowMetrics unused;
        GetReflowAndBoundingMetricsFor(childFrame, unused, bmChild);
      }

      if (firstTime) {
        firstTime = false;
        bm = bmChild;
        if (!stretchAll) {
          // we may get here for cases such as <msup><mo>...</mo> ... </msup>,
          // or <maction>...<mo>...</mo></maction>.
          break;
        }
      }
      else {
        if (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(mPresentationData.flags)) {
          // if we get here, it means this is container that will stack its children
          // vertically and fire an horizontal stretch on each them. This is the case
          // for \munder, \mover, \munderover. We just sum-up the size vertically.
          bm.descent += bmChild.ascent + bmChild.descent;
          // Sometimes non-spacing marks (when width is zero) are positioned
          // to the left of the origin, but it is the distance between left
          // and right bearing that is important rather than the offsets from
          // the origin.
          if (bmChild.width == 0) {
            bmChild.rightBearing -= bmChild.leftBearing;
            bmChild.leftBearing = 0;
          }
          if (bm.leftBearing > bmChild.leftBearing)
            bm.leftBearing = bmChild.leftBearing;
          if (bm.rightBearing < bmChild.rightBearing)
            bm.rightBearing = bmChild.rightBearing;
        }
        else if (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags)) {
          // just sum-up the sizes horizontally.
          bm += bmChild;
        }
        else {
          NS_ERROR("unexpected case in GetPreferredStretchSize");
          break;
        }
      }
      childFrame = childFrame->GetNextSibling();
    }
    aPreferredStretchSize = bm;
  }
}

NS_IMETHODIMP
nsMathMLContainerFrame::Stretch(nsRenderingContext& aRenderingContext,
                                nsStretchDirection   aStretchDirection,
                                nsBoundingMetrics&   aContainerSize,
                                nsHTMLReflowMetrics& aDesiredStretchSize)
{
  if (NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags)) {

    if (NS_MATHML_STRETCH_WAS_DONE(mPresentationData.flags)) {
      NS_WARNING("it is wrong to fire stretch more than once on a frame");
      return NS_OK;
    }
    mPresentationData.flags |= NS_MATHML_STRETCH_DONE;

    if (NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
      NS_WARNING("it is wrong to fire stretch on a erroneous frame");
      return NS_OK;
    }

    // Pass the stretch to the base child ...

    nsIFrame* baseFrame = mPresentationData.baseFrame;
    if (baseFrame) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(baseFrame);
      NS_ASSERTION(mathMLFrame, "Something is wrong somewhere");
      if (mathMLFrame) {
        bool stretchAll =
          NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags) ||
          NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(mPresentationData.flags);

        // And the trick is that the child's rect.x is still holding the descent,
        // and rect.y is still holding the ascent ...
        nsHTMLReflowMetrics childSize(aDesiredStretchSize);
        GetReflowAndBoundingMetricsFor(baseFrame, childSize, childSize.mBoundingMetrics);

        // See if we should downsize and confine the stretch to us...
        // XXX there may be other cases where we can downsize the stretch,
        // e.g., the first &Sum; might appear big in the following situation
        // <math xmlns='http://www.w3.org/1998/Math/MathML'>
        //   <mstyle>
        //     <msub>
        //        <msub><mo>&Sum;</mo><mfrac><mi>a</mi><mi>b</mi></mfrac></msub>
        //        <msub><mo>&Sum;</mo><mfrac><mi>a</mi><mi>b</mi></mfrac></msub>
        //      </msub>
        //   </mstyle>
        // </math>
        nsBoundingMetrics containerSize = aContainerSize;
        if (aStretchDirection != NS_STRETCH_DIRECTION_DEFAULT &&
            aStretchDirection != mEmbellishData.direction) {
          if (mEmbellishData.direction == NS_STRETCH_DIRECTION_UNSUPPORTED) {
            containerSize = childSize.mBoundingMetrics;
          }
          else {
            GetPreferredStretchSize(aRenderingContext, 
                                    stretchAll ? STRETCH_CONSIDER_EMBELLISHMENTS : 0,
                                    mEmbellishData.direction, containerSize);
          }
        }

        // do the stretching...
        mathMLFrame->Stretch(aRenderingContext,
                             mEmbellishData.direction, containerSize, childSize);
        // store the updated metrics
        SaveReflowAndBoundingMetricsFor(baseFrame, childSize,
                                        childSize.mBoundingMetrics);
        
        // Remember the siblings which were _deferred_.
        // Now that this embellished child may have changed, we need to
        // fire the stretch on its siblings using our updated size

        if (stretchAll) {

          nsStretchDirection stretchDir =
            NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags) ?
              NS_STRETCH_DIRECTION_VERTICAL : NS_STRETCH_DIRECTION_HORIZONTAL;

          GetPreferredStretchSize(aRenderingContext, STRETCH_CONSIDER_EMBELLISHMENTS,
                                  stretchDir, containerSize);

          nsIFrame* childFrame = mFrames.FirstChild();
          while (childFrame) {
            if (childFrame != mPresentationData.baseFrame) {
              mathMLFrame = do_QueryFrame(childFrame);
              if (mathMLFrame) {
                // retrieve the metrics that was stored at the previous pass
                GetReflowAndBoundingMetricsFor(childFrame, 
                  childSize, childSize.mBoundingMetrics);
                // do the stretching...
                mathMLFrame->Stretch(aRenderingContext, stretchDir,
                                     containerSize, childSize);
                // store the updated metrics
                SaveReflowAndBoundingMetricsFor(childFrame, childSize,
                                                childSize.mBoundingMetrics);
              }
            }
            childFrame = childFrame->GetNextSibling();
          }
        }

        // re-position all our children
        nsresult rv = Place(aRenderingContext, true, aDesiredStretchSize);
        if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
          // Make sure the child frames get their DidReflow() calls.
          DidReflowChildren(mFrames.FirstChild());
        }

        // If our parent is not embellished, it means we are the outermost embellished
        // container and so we put the spacing, otherwise we don't include the spacing,
        // the outermost embellished container will take care of it.

        nsEmbellishData parentData;
        GetEmbellishDataFrom(mParent, parentData);
        // ensure that we are the embellished child, not just a sibling
        // (need to test coreFrame since <mfrac> resets other things)
        if (parentData.coreFrame != mEmbellishData.coreFrame) {
          // (we fetch values from the core since they may use units that depend
          // on style data, and style changes could have occurred in the core since
          // our last visit there)
          nsEmbellishData coreData;
          GetEmbellishDataFrom(mEmbellishData.coreFrame, coreData);

          mBoundingMetrics.width +=
            coreData.leadingSpace + coreData.trailingSpace;
          aDesiredStretchSize.width = mBoundingMetrics.width;
          aDesiredStretchSize.mBoundingMetrics.width = mBoundingMetrics.width;

          nscoord dx = (StyleVisibility()->mDirection ?
                        coreData.trailingSpace : coreData.leadingSpace);
          if (dx != 0) {
            mBoundingMetrics.leftBearing += dx;
            mBoundingMetrics.rightBearing += dx;
            aDesiredStretchSize.mBoundingMetrics.leftBearing += dx;
            aDesiredStretchSize.mBoundingMetrics.rightBearing += dx;

            nsIFrame* childFrame = mFrames.FirstChild();
            while (childFrame) {
              childFrame->SetPosition(childFrame->GetPosition()
                                      + nsPoint(dx, 0));
              childFrame = childFrame->GetNextSibling();
            }
          }
        }

        // Finished with these:
        ClearSavedChildMetrics();
        // Set our overflow area
        GatherAndStoreOverflow(&aDesiredStretchSize);
      }
    }
  }
  return NS_OK;
}

nsresult
nsMathMLContainerFrame::FinalizeReflow(nsRenderingContext& aRenderingContext,
                                       nsHTMLReflowMetrics& aDesiredSize)
{
  // During reflow, we use rect.x and rect.y as placeholders for the child's ascent
  // and descent in expectation of a stretch command. Hence we need to ensure that
  // a stretch command will actually be fired later on, after exiting from our
  // reflow. If the stretch is not fired, the rect.x, and rect.y will remain
  // with inappropriate data causing children to be improperly positioned.
  // This helper method checks to see if our parent will fire a stretch command
  // targeted at us. If not, we go ahead and fire an involutive stretch on
  // ourselves. This will clear all the rect.x and rect.y, and return our
  // desired size.


  // First, complete the post-reflow hook.
  // We use the information in our children rectangles to position them.
  // If placeOrigin==false, then Place() will not touch rect.x, and rect.y.
  // They will still be holding the ascent and descent for each child.

  // The first clause caters for any non-embellished container.
  // The second clause is for a container which won't fire stretch even though it is
  // embellished, e.g., as in <mfrac><mo>...</mo> ... </mfrac>, the test is convoluted
  // because it excludes the particular case of the core <mo>...</mo> itself.
  // (<mo> needs to fire stretch on its MathMLChar in any case to initialize it)
  bool placeOrigin = !NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags) ||
                       (mEmbellishData.coreFrame != this && !mPresentationData.baseFrame &&
                        mEmbellishData.direction == NS_STRETCH_DIRECTION_UNSUPPORTED);
  nsresult rv = Place(aRenderingContext, placeOrigin, aDesiredSize);

  // Place() will call FinishReflowChild() when placeOrigin is true but if
  // it returns before reaching FinishReflowChild() due to errors we need
  // to fulfill the reflow protocol by calling DidReflow for the child frames
  // that still needs it here (or we may crash - bug 366012).
  // If placeOrigin is false we should reach Place() with aPlaceOrigin == true
  // through Stretch() eventually.
  if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
    DidReflowChildren(GetFirstPrincipalChild());
    return rv;
  }

  bool parentWillFireStretch = false;
  if (!placeOrigin) {
    // This means the rect.x and rect.y of our children were not set!!
    // Don't go without checking to see if our parent will later fire a Stretch() command
    // targeted at us. The Stretch() will cause the rect.x and rect.y to clear...
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(mParent);
    if (mathMLFrame) {
      nsEmbellishData embellishData;
      nsPresentationData presentationData;
      mathMLFrame->GetEmbellishData(embellishData);
      mathMLFrame->GetPresentationData(presentationData);
      if (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(presentationData.flags) ||
          NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(presentationData.flags) ||
          (NS_MATHML_IS_EMBELLISH_OPERATOR(embellishData.flags)
            && presentationData.baseFrame == this))
      {
        parentWillFireStretch = true;
      }
    }
    if (!parentWillFireStretch) {
      // There is nobody who will fire the stretch for us, we do it ourselves!

      bool stretchAll =
        /* NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags) || */
        NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(mPresentationData.flags);

      nsBoundingMetrics defaultSize;
      if (mEmbellishData.coreFrame == this /* case of a bare <mo>...</mo> itself */
          || stretchAll) { /* or <mover><mo>...</mo>...</mover>, or friends */
        // use our current size as computed earlier by Place()
        defaultSize = aDesiredSize.mBoundingMetrics;
      }
      else { /* case of <msup><mo>...</mo>...</msup> or friends */
        // compute a size that doesn't include embellishments
        GetPreferredStretchSize(aRenderingContext, 0, mEmbellishData.direction,
                                defaultSize);
      }
      Stretch(aRenderingContext, NS_STRETCH_DIRECTION_DEFAULT, defaultSize,
              aDesiredSize);
#ifdef DEBUG
      {
        // The Place() call above didn't request FinishReflowChild(),
        // so let's check that we eventually did through Stretch().
        nsIFrame* childFrame = GetFirstPrincipalChild();
        for ( ; childFrame; childFrame = childFrame->GetNextSibling()) {
          NS_ASSERTION(!(childFrame->GetStateBits() & NS_FRAME_IN_REFLOW),
                       "DidReflow() was never called");
        }
      }
#endif
    }
  }

  // see if we should fix the spacing
  FixInterFrameSpacing(aDesiredSize);

  // Also return our bounding metrics
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

  if (!parentWillFireStretch) {
    // Not expecting a stretch.
    // Finished with these:
    ClearSavedChildMetrics();
    // Set our overflow area.
    GatherAndStoreOverflow(&aDesiredSize);
  }

  return NS_OK;
}


/* /////////////
 * nsIMathMLFrame - support methods for scripting elements (nested frames
 * within msub, msup, msubsup, munder, mover, munderover, mmultiscripts,
 * mfrac, mroot, mtable).
 * =============================================================================
 */

// helper to let the update of presentation data pass through
// a subtree that may contain non-mathml container frames
/* static */ void
nsMathMLContainerFrame::PropagatePresentationDataFor(nsIFrame*       aFrame,
                                                     uint32_t        aFlagsValues,
                                                     uint32_t        aFlagsToUpdate)
{
  if (!aFrame || !aFlagsToUpdate)
    return;
  nsIMathMLFrame* mathMLFrame = do_QueryFrame(aFrame);
  if (mathMLFrame) {
    // update
    mathMLFrame->UpdatePresentationData(aFlagsValues,
                                        aFlagsToUpdate);
    // propagate using the base method to make sure that the control
    // is passed on to MathML frames that may be overloading the method
    mathMLFrame->UpdatePresentationDataFromChildAt(0, -1,
      aFlagsValues, aFlagsToUpdate);
  }
  else {
    // propagate down the subtrees
    nsIFrame* childFrame = aFrame->GetFirstPrincipalChild();
    while (childFrame) {
      PropagatePresentationDataFor(childFrame,
        aFlagsValues, aFlagsToUpdate);
      childFrame = childFrame->GetNextSibling();
    }
  }
}

/* static */ void
nsMathMLContainerFrame::PropagatePresentationDataFromChildAt(nsIFrame*       aParentFrame,
                                                             int32_t         aFirstChildIndex,
                                                             int32_t         aLastChildIndex,
                                                             uint32_t        aFlagsValues,
                                                             uint32_t        aFlagsToUpdate)
{
  if (!aParentFrame || !aFlagsToUpdate)
    return;
  int32_t index = 0;
  nsIFrame* childFrame = aParentFrame->GetFirstPrincipalChild();
  while (childFrame) {
    if ((index >= aFirstChildIndex) &&
        ((aLastChildIndex <= 0) || ((aLastChildIndex > 0) &&
         (index <= aLastChildIndex)))) {
      PropagatePresentationDataFor(childFrame,
        aFlagsValues, aFlagsToUpdate);
    }
    index++;
    childFrame = childFrame->GetNextSibling();
  }
}

/* //////////////////
 * Frame construction
 * =============================================================================
 */


void
nsMathMLContainerFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                         const nsRect&           aDirtyRect,
                                         const nsDisplayListSet& aLists)
{
  // report an error if something wrong was found in this frame
  if (NS_MATHML_HAS_ERROR(mPresentationData.flags)) {
    if (!IsVisibleForPainting(aBuilder))
      return;

    aLists.Content()->AppendNewToTop(
      new (aBuilder) nsDisplayMathMLError(aBuilder, this));
    return;
  }

  DisplayBorderBackgroundOutline(aBuilder, aLists);

  BuildDisplayListForNonBlockChildren(aBuilder, aDirtyRect, aLists,
                                      DISPLAY_CHILD_INLINE);

#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
  // for visual debug
  // ----------------
  // if you want to see your bounding box, make sure to properly fill
  // your mBoundingMetrics and mReference point, and set
  // mPresentationData.flags |= NS_MATHML_SHOW_BOUNDING_METRICS
  // in the Init() of your sub-class
  DisplayBoundingMetrics(aBuilder, this, mReference, mBoundingMetrics, aLists);
#endif
}

// Note that this method re-builds the automatic data in the children -- not
// in aParentFrame itself (except for those particular operations that the
// parent frame may do in its TransmitAutomaticData()).
/* static */ void
nsMathMLContainerFrame::RebuildAutomaticDataForChildren(nsIFrame* aParentFrame)
{
  // 1. As we descend the tree, make each child frame inherit data from
  // the parent
  // 2. As we ascend the tree, transmit any specific change that we want
  // down the subtrees
  nsIFrame* childFrame = aParentFrame->GetFirstPrincipalChild();
  while (childFrame) {
    nsIMathMLFrame* childMathMLFrame = do_QueryFrame(childFrame);
    if (childMathMLFrame) {
      childMathMLFrame->InheritAutomaticData(aParentFrame);
    }
    RebuildAutomaticDataForChildren(childFrame);
    childFrame = childFrame->GetNextSibling();
  }
  nsIMathMLFrame* mathMLFrame = do_QueryFrame(aParentFrame);
  if (mathMLFrame) {
    mathMLFrame->TransmitAutomaticData();
  }
}

/* static */ nsresult
nsMathMLContainerFrame::ReLayoutChildren(nsIFrame* aParentFrame)
{
  if (!aParentFrame)
    return NS_OK;

  // walk-up to the first frame that is a MathML frame, stop if we reach <math>
  nsIFrame* frame = aParentFrame;
  while (1) {
     nsIFrame* parent = frame->GetParent();
     if (!parent || !parent->GetContent())
       break;

    // stop if it is a MathML frame
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(frame);
    if (mathMLFrame)
      break;

    // stop if we reach the root <math> tag
    nsIContent* content = frame->GetContent();
    NS_ASSERTION(content, "dangling frame without a content node");
    if (!content)
      break;
    if (content->GetNameSpaceID() == kNameSpaceID_MathML &&
        content->Tag() == nsGkAtoms::math)
      break;

    // mark the frame dirty, and continue to climb up.  It's important that
    // we're NOT doing this to the frame we plan to pass to FrameNeedsReflow()
    // XXXldb Why do we need to bother with this?  Marking ancestor
    // dirty (which we do below) should do a superset of the work this
    // does.
    frame->AddStateBits(NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN);

    frame = parent;
  }

  // re-sync the presentation data and embellishment data of our children
  RebuildAutomaticDataForChildren(frame);

  // Ask our parent frame to reflow us
  nsIFrame* parent = frame->GetParent();
  NS_ASSERTION(parent, "No parent to pass the reflow request up to");
  if (!parent)
    return NS_OK;

  frame->PresContext()->PresShell()->
    FrameNeedsReflow(frame, nsIPresShell::eStyleChange, NS_FRAME_IS_DIRTY);

  return NS_OK;
}

// There are precise rules governing children of a MathML frame,
// and properties such as the scriptlevel depends on those rules.
// Hence for things to work, callers must use Append/Insert/etc wisely.

nsresult
nsMathMLContainerFrame::ChildListChanged(int32_t aModType)
{
  // If this is an embellished frame we need to rebuild the
  // embellished hierarchy by walking-up to the parent of the
  // outermost embellished container.
  nsIFrame* frame = this;
  if (mEmbellishData.coreFrame) {
    nsIFrame* parent = mParent;
    nsEmbellishData embellishData;
    for ( ; parent; frame = parent, parent = parent->GetParent()) {
      GetEmbellishDataFrom(parent, embellishData);
      if (embellishData.coreFrame != mEmbellishData.coreFrame)
        break;

      // Important: do not do this to the frame we plan to pass to
      // ReLayoutChildren
      // XXXldb Why do we need to bother with this?  Marking ancestor
      // dirty (which we do below) should do a superset of the work this
      // does.
      frame->AddStateBits(NS_FRAME_IS_DIRTY | NS_FRAME_HAS_DIRTY_CHILDREN);
    }
  }
  return ReLayoutChildren(frame);
}

NS_IMETHODIMP
nsMathMLContainerFrame::AppendFrames(ChildListID     aListID,
                                     nsFrameList&    aFrameList)
{
  if (aListID != kPrincipalList) {
    return NS_ERROR_INVALID_ARG;
  }
  mFrames.AppendFrames(this, aFrameList);
  return ChildListChanged(nsIDOMMutationEvent::ADDITION);
}

NS_IMETHODIMP
nsMathMLContainerFrame::InsertFrames(ChildListID     aListID,
                                     nsIFrame*       aPrevFrame,
                                     nsFrameList&    aFrameList)
{
  if (aListID != kPrincipalList) {
    return NS_ERROR_INVALID_ARG;
  }
  // Insert frames after aPrevFrame
  mFrames.InsertFrames(this, aPrevFrame, aFrameList);
  return ChildListChanged(nsIDOMMutationEvent::ADDITION);
}

NS_IMETHODIMP
nsMathMLContainerFrame::RemoveFrame(ChildListID     aListID,
                                    nsIFrame*       aOldFrame)
{
  if (aListID != kPrincipalList) {
    return NS_ERROR_INVALID_ARG;
  }
  // remove the child frame
  mFrames.DestroyFrame(aOldFrame);
  return ChildListChanged(nsIDOMMutationEvent::REMOVAL);
}

NS_IMETHODIMP
nsMathMLContainerFrame::AttributeChanged(int32_t         aNameSpaceID,
                                         nsIAtom*        aAttribute,
                                         int32_t         aModType)
{
  // XXX Since they are numerous MathML attributes that affect layout, and
  // we can't check all of them here, play safe by requesting a reflow.
  // XXXldb This should only do work for attributes that cause changes!
  PresContext()->PresShell()->
    FrameNeedsReflow(this, nsIPresShell::eStyleChange, NS_FRAME_IS_DIRTY);

  return NS_OK;
}

void
nsMathMLContainerFrame::GatherAndStoreOverflow(nsHTMLReflowMetrics* aMetrics)
{
  // nsIFrame::FinishAndStoreOverflow likes the overflow area to include the
  // frame rectangle.
  aMetrics->SetOverflowAreasToDesiredBounds();

  // All non-child-frame content such as nsMathMLChars (and most child-frame
  // content) is included in mBoundingMetrics.
  nsRect boundingBox(mBoundingMetrics.leftBearing,
                     aMetrics->ascent - mBoundingMetrics.ascent,
                     mBoundingMetrics.rightBearing - mBoundingMetrics.leftBearing,
                     mBoundingMetrics.ascent + mBoundingMetrics.descent);

  // REVIEW: Maybe this should contribute only to visual overflow
  // and not scrollable?
  aMetrics->mOverflowAreas.UnionAllWith(boundingBox);

  // mBoundingMetrics does not necessarily include content of <mpadded>
  // elements whose mBoundingMetrics may not be representative of the true
  // bounds, and doesn't include the CSS2 outline rectangles of children, so
  // make such to include child overflow areas.
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    ConsiderChildOverflow(aMetrics->mOverflowAreas, childFrame);
    childFrame = childFrame->GetNextSibling();
  }

  FinishAndStoreOverflow(aMetrics);
}

bool
nsMathMLContainerFrame::UpdateOverflow()
{
  // Our overflow areas may have changed, so reflow the frame.
  PresContext()->PresShell()->FrameNeedsReflow(
    this, nsIPresShell::eResize, NS_FRAME_IS_DIRTY);

  // As we're reflowing, there's no need to propagate this change.
  return false;
}

nsresult 
nsMathMLContainerFrame::ReflowChild(nsIFrame*                aChildFrame,
                                    nsPresContext*           aPresContext,
                                    nsHTMLReflowMetrics&     aDesiredSize,
                                    const nsHTMLReflowState& aReflowState,
                                    nsReflowStatus&          aStatus)
{
  // Having foreign/hybrid children, e.g., from html markups, is not defined by
  // the MathML spec. But it can happen in practice, e.g., <html:img> allows us
  // to do some cool demos... or we may have a child that is an nsInlineFrame
  // from a generated content such as :before { content: open-quote } or 
  // :after { content: close-quote }. Unfortunately, the other frames out-there
  // may expect their own invariants that are not met when we mix things.
  // Hence we do not claim their support, but we will nevertheless attempt to keep
  // them in the flow, if we can get their desired size. We observed that most
  // frames may be reflowed generically, but nsInlineFrames need extra care.

#ifdef DEBUG
  nsInlineFrame* inlineFrame = do_QueryFrame(aChildFrame);
  NS_ASSERTION(!inlineFrame, "Inline frames should be wrapped in blocks");
#endif
  
  nsresult rv = nsContainerFrame::
         ReflowChild(aChildFrame, aPresContext, aDesiredSize, aReflowState,
                     0, 0, NS_FRAME_NO_MOVE_FRAME, aStatus);

  if (NS_FAILED(rv))
    return rv;

  if (aDesiredSize.ascent == nsHTMLReflowMetrics::ASK_FOR_BASELINE) {
    // This will be suitable for inline frames, which are wrapped in a block.
    if(!nsLayoutUtils::GetLastLineBaseline(aChildFrame,
                                           &aDesiredSize.ascent)) {
      // We don't expect any other block children so just place the frame on
      // the baseline instead of going through DidReflow() and
      // GetBaseline().  This is what nsFrame::GetBaseline() will do anyway.
      aDesiredSize.ascent = aDesiredSize.height;
    }
  }
  if (IsForeignChild(aChildFrame)) {
    // use ComputeTightBounds API as aDesiredSize.mBoundingMetrics is not set.
    nsRect r = aChildFrame->ComputeTightBounds(aReflowState.rendContext->ThebesContext());
    aDesiredSize.mBoundingMetrics.leftBearing = r.x;
    aDesiredSize.mBoundingMetrics.rightBearing = r.XMost();
    aDesiredSize.mBoundingMetrics.ascent = aDesiredSize.ascent - r.y;
    aDesiredSize.mBoundingMetrics.descent = r.YMost() - aDesiredSize.ascent;
    aDesiredSize.mBoundingMetrics.width = aDesiredSize.width;
  }
  return rv;
}

NS_IMETHODIMP
nsMathMLContainerFrame::Reflow(nsPresContext*           aPresContext,
                               nsHTMLReflowMetrics&     aDesiredSize,
                               const nsHTMLReflowState& aReflowState,
                               nsReflowStatus&          aStatus)
{
  aDesiredSize.width = aDesiredSize.height = 0;
  aDesiredSize.ascent = 0;
  aDesiredSize.mBoundingMetrics = nsBoundingMetrics();

  /////////////
  // Reflow children
  // Asking each child to cache its bounding metrics

  nsReflowStatus childStatus;
  nsSize availSize(aReflowState.ComputedWidth(), NS_UNCONSTRAINEDSIZE);
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    nsHTMLReflowMetrics childDesiredSize(aDesiredSize.mFlags);
    nsHTMLReflowState childReflowState(aPresContext, aReflowState,
                                       childFrame, availSize);
    nsresult rv = ReflowChild(childFrame, aPresContext, childDesiredSize,
                              childReflowState, childStatus);
    //NS_ASSERTION(NS_FRAME_IS_COMPLETE(childStatus), "bad status");
    if (NS_FAILED(rv)) {
      // Call DidReflow() for the child frames we successfully did reflow.
      DidReflowChildren(mFrames.FirstChild(), childFrame);
      return rv;
    }

    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);
    childFrame = childFrame->GetNextSibling();
  }

  /////////////
  // If we are a container which is entitled to stretch its children, then we
  // ask our stretchy children to stretch themselves

  // The stretching of siblings of an embellished child is _deferred_ until
  // after finishing the stretching of the embellished child - bug 117652

  if (!NS_MATHML_IS_EMBELLISH_OPERATOR(mEmbellishData.flags) &&
      (NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags) ||
       NS_MATHML_WILL_STRETCH_ALL_CHILDREN_HORIZONTALLY(mPresentationData.flags))) {

    // get the stretchy direction
    nsStretchDirection stretchDir =
      NS_MATHML_WILL_STRETCH_ALL_CHILDREN_VERTICALLY(mPresentationData.flags) 
      ? NS_STRETCH_DIRECTION_VERTICAL 
      : NS_STRETCH_DIRECTION_HORIZONTAL;

    // what size should we use to stretch our stretchy children
    // We don't use STRETCH_CONSIDER_ACTUAL_SIZE -- because our size is not known yet
    // We don't use STRETCH_CONSIDER_EMBELLISHMENTS -- because we don't want to
    // include them in the caculations of the size of stretchy elements
    nsBoundingMetrics containerSize;
    GetPreferredStretchSize(*aReflowState.rendContext, 0, stretchDir,
                            containerSize);

    // fire the stretch on each child
    childFrame = mFrames.FirstChild();
    while (childFrame) {
      nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
      if (mathMLFrame) {
        // retrieve the metrics that was stored at the previous pass
        nsHTMLReflowMetrics childDesiredSize;
        GetReflowAndBoundingMetricsFor(childFrame,
          childDesiredSize, childDesiredSize.mBoundingMetrics);

        mathMLFrame->Stretch(*aReflowState.rendContext, stretchDir,
                             containerSize, childDesiredSize);
        // store the updated metrics
        SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                        childDesiredSize.mBoundingMetrics);
      }
      childFrame = childFrame->GetNextSibling();
    }
  }

  /////////////
  // Place children now by re-adjusting the origins to align the baselines
  FinalizeReflow(*aReflowState.rendContext, aDesiredSize);

  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}

/* virtual */ nscoord
nsMathMLContainerFrame::GetMinWidth(nsRenderingContext *aRenderingContext)
{
  nscoord result;
  DISPLAY_MIN_WIDTH(this, result);
  result = GetIntrinsicWidth(aRenderingContext);
  return result;
}

/* virtual */ nscoord
nsMathMLContainerFrame::GetPrefWidth(nsRenderingContext *aRenderingContext)
{
  nscoord result;
  DISPLAY_MIN_WIDTH(this, result);
  result = GetIntrinsicWidth(aRenderingContext);
  return result;
}

/* virtual */ nscoord
nsMathMLContainerFrame::GetIntrinsicWidth(nsRenderingContext* aRenderingContext)
{
  // Get child widths
  nsIFrame* childFrame = mFrames.FirstChild();
  while (childFrame) {
    // XXX This includes margin while Reflow currently doesn't consider
    // margin, so we may end up with too much space, but, with stretchy
    // characters, this is an approximation anyway.
    nscoord width =
      nsLayoutUtils::IntrinsicForContainer(aRenderingContext, childFrame,
                                           nsLayoutUtils::PREF_WIDTH);

    nsHTMLReflowMetrics childDesiredSize;
    childDesiredSize.width = width;
    childDesiredSize.mBoundingMetrics.width = width;
    // TODO: we need nsIFrame::GetIntrinsicHBounds() for better values here.
    childDesiredSize.mBoundingMetrics.leftBearing = 0;
    childDesiredSize.mBoundingMetrics.rightBearing = width;

    SaveReflowAndBoundingMetricsFor(childFrame, childDesiredSize,
                                    childDesiredSize.mBoundingMetrics);

    childFrame = childFrame->GetNextSibling();
  }

  // Measure
  nsHTMLReflowMetrics desiredSize;
  nsresult rv = MeasureForWidth(*aRenderingContext, desiredSize);
  if (NS_FAILED(rv)) {
    ReflowError(*aRenderingContext, desiredSize);
  }

  ClearSavedChildMetrics();

  return desiredSize.width;
}

/* virtual */ nsresult
nsMathMLContainerFrame::MeasureForWidth(nsRenderingContext& aRenderingContext,
                                        nsHTMLReflowMetrics& aDesiredSize)
{
  return Place(aRenderingContext, false, aDesiredSize);
}


// see spacing table in Chapter 18, TeXBook (p.170)
// Our table isn't quite identical to TeX because operators have 
// built-in values for lspace & rspace in the Operator Dictionary.
static int32_t kInterFrameSpacingTable[eMathMLFrameType_COUNT][eMathMLFrameType_COUNT] =
{
  // in units of muspace.
  // upper half of the byte is set if the
  // spacing is not to be used for scriptlevel > 0

  /*           Ord  OpOrd OpInv OpUsr Inner Italic Upright */
  /*Ord  */   {0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x00},
  /*OpOrd*/   {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
  /*OpInv*/   {0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00},
  /*OpUsr*/   {0x01, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01},
  /*Inner*/   {0x01, 0x00, 0x00, 0x01, 0x01, 0x01, 0x01},
  /*Italic*/  {0x00, 0x00, 0x00, 0x01, 0x01, 0x00, 0x01},
  /*Upright*/ {0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x00}
};

#define GET_INTERSPACE(scriptlevel_, frametype1_, frametype2_, space_)  \
   /* no space if there is a frame that we know nothing about */        \
   if (frametype1_ == eMathMLFrameType_UNKNOWN ||                       \
       frametype2_ == eMathMLFrameType_UNKNOWN)                         \
    space_ = 0;                                                         \
  else {                                                                \
    space_ = kInterFrameSpacingTable[frametype1_][frametype2_];         \
    space_ = (scriptlevel_ > 0 && (space_ & 0xF0))                      \
      ? 0 /* spacing is disabled */                                     \
      : space_ & 0x0F;                                                  \
  }                                                                     \

// This function computes the inter-space between two frames. However, 
// since invisible operators need special treatment, the inter-space may
// be delayed when an invisible operator is encountered. In this case,
// the function will carry the inter-space forward until it is determined
// that it can be applied properly (i.e., until we encounter a visible
// frame where to decide whether to accept or reject the inter-space).
// aFromFrameType: remembers the frame when the carry-forward initiated.
// aCarrySpace: keeps track of the inter-space that is delayed.
// @returns: current inter-space (which is 0 when the true inter-space is
// delayed -- and thus has no effect since the frame is invisible anyway).
static nscoord
GetInterFrameSpacing(int32_t           aScriptLevel,
                     eMathMLFrameType  aFirstFrameType,
                     eMathMLFrameType  aSecondFrameType,
                     eMathMLFrameType* aFromFrameType, // IN/OUT
                     int32_t*          aCarrySpace)    // IN/OUT
{
  eMathMLFrameType firstType = aFirstFrameType;
  eMathMLFrameType secondType = aSecondFrameType;

  int32_t space;
  GET_INTERSPACE(aScriptLevel, firstType, secondType, space);

  // feedback control to avoid the inter-space to be added when not necessary
  if (secondType == eMathMLFrameType_OperatorInvisible) {
    // see if we should start to carry the space forward until we
    // encounter a visible frame
    if (*aFromFrameType == eMathMLFrameType_UNKNOWN) {
      *aFromFrameType = firstType;
      *aCarrySpace = space;
    }
    // keep carrying *aCarrySpace forward, while returning 0 for this stage
    space = 0;
  }
  else if (*aFromFrameType != eMathMLFrameType_UNKNOWN) {
    // no carry-forward anymore, get the real inter-space between
    // the two frames of interest

    firstType = *aFromFrameType;

    // But... the invisible operator that we encountered earlier could
    // be sitting between italic and upright identifiers, e.g.,
    //
    // 1. <mi>sin</mi> <mo>&ApplyFunction;</mo> <mi>x</mi>
    // 2. <mi>x</mi> <mo>&InvisibileTime;</mo> <mi>sin</mi>
    //
    // the trick to get the inter-space in either situation
    // is to promote "<mi>sin</mi><mo>&ApplyFunction;</mo>" and
    // "<mo>&InvisibileTime;</mo><mi>sin</mi>" to user-defined operators...
    if (firstType == eMathMLFrameType_UprightIdentifier) {
      firstType = eMathMLFrameType_OperatorUserDefined;
    }
    else if (secondType == eMathMLFrameType_UprightIdentifier) {
      secondType = eMathMLFrameType_OperatorUserDefined;
    }

    GET_INTERSPACE(aScriptLevel, firstType, secondType, space);

    // Now, we have two values: the computed space and the space that
    // has been carried forward until now. Which value do we pick?
    // If the second type is an operator (e.g., fence), it already has
    // built-in lspace & rspace, so we let them win. Otherwise we pick
    // the max between the two values that we have.
    if (secondType != eMathMLFrameType_OperatorOrdinary &&
        space < *aCarrySpace)
      space = *aCarrySpace;

    // reset everything now that the carry-forward is done
    *aFromFrameType = eMathMLFrameType_UNKNOWN;
    *aCarrySpace = 0;
  }

  return space;
}

static nscoord GetThinSpace(const nsStyleFont* aStyleFont)
{
  return NSToCoordRound(float(aStyleFont->mFont.size)*float(3) / float(18));
}

class nsMathMLContainerFrame::RowChildFrameIterator {
public:
  explicit RowChildFrameIterator(nsMathMLContainerFrame* aParentFrame) :
    mParentFrame(aParentFrame),
    mX(0),
    mCarrySpace(0),
    mFromFrameType(eMathMLFrameType_UNKNOWN),
    mRTL(aParentFrame->StyleVisibility()->mDirection)
  {
    if (!mRTL) {
      mChildFrame = aParentFrame->mFrames.FirstChild();
    } else {
      mChildFrame = aParentFrame->mFrames.LastChild();
    }

    if (!mChildFrame)
      return;

    InitMetricsForChild();
  }

  RowChildFrameIterator& operator++()
  {
    // add child size + italic correction
    mX += mSize.mBoundingMetrics.width + mItalicCorrection;

    if (!mRTL) {
      mChildFrame = mChildFrame->GetNextSibling();
    } else {
      mChildFrame = mChildFrame->GetPrevSibling();
    }

    if (!mChildFrame)
      return *this;

    eMathMLFrameType prevFrameType = mChildFrameType;
    InitMetricsForChild();

    // add inter frame spacing
    const nsStyleFont* font = mParentFrame->StyleFont();
    nscoord space =
      GetInterFrameSpacing(font->mScriptLevel,
                           prevFrameType, mChildFrameType,
                           &mFromFrameType, &mCarrySpace);
    mX += space * GetThinSpace(font);
    return *this;
  }

  nsIFrame* Frame() const { return mChildFrame; }
  nscoord X() const { return mX; }
  const nsHTMLReflowMetrics& ReflowMetrics() const { return mSize; }
  nscoord Ascent() const { return mSize.ascent; }
  nscoord Descent() const { return mSize.height - mSize.ascent; }
  const nsBoundingMetrics& BoundingMetrics() const {
    return mSize.mBoundingMetrics;
  }

private:
  const nsMathMLContainerFrame* mParentFrame;
  nsIFrame* mChildFrame;
  nsHTMLReflowMetrics mSize;
  nscoord mX;

  nscoord mItalicCorrection;
  eMathMLFrameType mChildFrameType;
  int32_t mCarrySpace;
  eMathMLFrameType mFromFrameType;

  bool mRTL;

  void InitMetricsForChild()
  {
    GetReflowAndBoundingMetricsFor(mChildFrame, mSize, mSize.mBoundingMetrics,
                                   &mChildFrameType);
    nscoord leftCorrection, rightCorrection;
    GetItalicCorrection(mSize.mBoundingMetrics,
                        leftCorrection, rightCorrection);
    if (!mChildFrame->GetPrevSibling() &&
        mParentFrame->GetContent()->Tag() == nsGkAtoms::msqrt_) {
      // Remove leading correction in <msqrt> because the sqrt glyph itself is
      // there first.
      if (!mRTL) {
        leftCorrection = 0;
      } else {
        rightCorrection = 0;
      }
    }
    // add left correction -- this fixes the problem of the italic 'f'
    // e.g., <mo>q</mo> <mi>f</mi> <mo>I</mo> 
    mX += leftCorrection;
    mItalicCorrection = rightCorrection;
  }
};

/* virtual */ nsresult
nsMathMLContainerFrame::Place(nsRenderingContext& aRenderingContext,
                              bool                 aPlaceOrigin,
                              nsHTMLReflowMetrics& aDesiredSize)
{
  // This is needed in case this frame is empty (i.e., no child frames)
  mBoundingMetrics = nsBoundingMetrics();

  RowChildFrameIterator child(this);
  nscoord ascent = 0, descent = 0;
  while (child.Frame()) {
    if (descent < child.Descent())
      descent = child.Descent();
    if (ascent < child.Ascent())
      ascent = child.Ascent();
    // add the child size
    mBoundingMetrics.width = child.X();
    mBoundingMetrics += child.BoundingMetrics();
    ++child;
  }
  // Add the italic correction at the end (including the last child).
  // This gives a nice gap between math and non-math frames, and still
  // gives the same math inter-spacing in case this frame connects to
  // another math frame
  mBoundingMetrics.width = child.X();

  aDesiredSize.width = std::max(0, mBoundingMetrics.width);
  aDesiredSize.height = ascent + descent;
  aDesiredSize.ascent = ascent;
  aDesiredSize.mBoundingMetrics = mBoundingMetrics;

  mReference.x = 0;
  mReference.y = aDesiredSize.ascent;

  //////////////////
  // Place Children

  if (aPlaceOrigin) {
    PositionRowChildFrames(0, aDesiredSize.ascent);
  }

  return NS_OK;
}

void
nsMathMLContainerFrame::PositionRowChildFrames(nscoord aOffsetX,
                                               nscoord aBaseline)
{
  RowChildFrameIterator child(this);
  while (child.Frame()) {
    nscoord dx = aOffsetX + child.X();
    nscoord dy = aBaseline - child.Ascent();
    FinishReflowChild(child.Frame(), PresContext(), nullptr,
                      child.ReflowMetrics(), dx, dy, 0);
    ++child;
  }
}

class ForceReflow : public nsIReflowCallback {
public:
  virtual bool ReflowFinished() {
    return true;
  }
  virtual void ReflowCallbackCanceled() {}
};

// We only need one of these so we just make it a static global, no need
// to dynamically allocate/destroy it.
static ForceReflow gForceReflow;

void
nsMathMLContainerFrame::SetIncrementScriptLevel(int32_t aChildIndex, bool aIncrement)
{
  nsIFrame* child = PrincipalChildList().FrameAt(aChildIndex);
  if (!child)
    return;
  nsIContent* content = child->GetContent();
  if (!content->IsMathML())
    return;
  nsMathMLElement* element = static_cast<nsMathMLElement*>(content);

  if (element->GetIncrementScriptLevel() == aIncrement)
    return;

  // XXXroc this does a ContentStatesChanged, is it safe to call here? If
  // not we should do it in a post-reflow callback.
  element->SetIncrementScriptLevel(aIncrement, true);
  PresContext()->PresShell()->PostReflowCallback(&gForceReflow);
}

// helpers to fix the inter-spacing when <math> is the only parent
// e.g., it fixes <math> <mi>f</mi> <mo>q</mo> <mi>f</mi> <mo>I</mo> </math>

static nscoord
GetInterFrameSpacingFor(int32_t         aScriptLevel,
                        nsIFrame*       aParentFrame,
                        nsIFrame*       aChildFrame)
{
  nsIFrame* childFrame = aParentFrame->GetFirstPrincipalChild();
  if (!childFrame || aChildFrame == childFrame)
    return 0;

  int32_t carrySpace = 0;
  eMathMLFrameType fromFrameType = eMathMLFrameType_UNKNOWN;
  eMathMLFrameType prevFrameType = eMathMLFrameType_UNKNOWN;
  eMathMLFrameType childFrameType = nsMathMLFrame::GetMathMLFrameTypeFor(childFrame);
  childFrame = childFrame->GetNextSibling();
  while (childFrame) {
    prevFrameType = childFrameType;
    childFrameType = nsMathMLFrame::GetMathMLFrameTypeFor(childFrame);
    nscoord space = GetInterFrameSpacing(aScriptLevel,
      prevFrameType, childFrameType, &fromFrameType, &carrySpace);
    if (aChildFrame == childFrame) {
      // get thinspace
      nsStyleContext* parentContext = aParentFrame->StyleContext();
      nscoord thinSpace = GetThinSpace(parentContext->StyleFont());
      // we are done
      return space * thinSpace;
    }
    childFrame = childFrame->GetNextSibling();
  }

  NS_NOTREACHED("child not in the childlist of its parent");
  return 0;
}

nscoord
nsMathMLContainerFrame::FixInterFrameSpacing(nsHTMLReflowMetrics& aDesiredSize)
{
  nscoord gap = 0;
  nsIContent* parentContent = mParent->GetContent();
  if (MOZ_UNLIKELY(!parentContent)) {
    return 0;
  }
  nsIAtom *parentTag = parentContent->Tag();
  if (parentContent->GetNameSpaceID() == kNameSpaceID_MathML && 
      (parentTag == nsGkAtoms::math || parentTag == nsGkAtoms::mtd_)) {
    gap = GetInterFrameSpacingFor(StyleFont()->mScriptLevel, mParent, this);
    // add our own italic correction
    nscoord leftCorrection = 0, italicCorrection = 0;
    GetItalicCorrection(mBoundingMetrics, leftCorrection, italicCorrection);
    gap += leftCorrection;
    // see if we should shift our children to account for the correction
    if (gap) {
      nsIFrame* childFrame = mFrames.FirstChild();
      while (childFrame) {
        childFrame->SetPosition(childFrame->GetPosition() + nsPoint(gap, 0));
        childFrame = childFrame->GetNextSibling();
      }
      mBoundingMetrics.leftBearing += gap;
      mBoundingMetrics.rightBearing += gap;
      mBoundingMetrics.width += gap;
      aDesiredSize.width += gap;
    }
    mBoundingMetrics.width += italicCorrection;
    aDesiredSize.width += italicCorrection;
  }
  return gap;
}

/* static */ void
nsMathMLContainerFrame::DidReflowChildren(nsIFrame* aFirst, nsIFrame* aStop)

{
  if (MOZ_UNLIKELY(!aFirst))
    return;

  for (nsIFrame* frame = aFirst;
       frame != aStop;
       frame = frame->GetNextSibling()) {
    NS_ASSERTION(frame, "aStop isn't a sibling");
    if (frame->GetStateBits() & NS_FRAME_IN_REFLOW) {
      // finish off principal descendants, too
      nsIFrame* grandchild = frame->GetFirstPrincipalChild();
      if (grandchild)
        DidReflowChildren(grandchild, nullptr);

      frame->DidReflow(frame->PresContext(), nullptr,
                       nsDidReflowStatus::FINISHED);
    }
  }
}

// helper used by mstyle, mphantom, mpadded and mrow in their implementations
// of TransmitAutomaticData().
nsresult
nsMathMLContainerFrame::TransmitAutomaticDataForMrowLikeElement()
{
  //
  // One loop to check both conditions below:
  //
  // 1) whether all the children of the mrow-like element are space-like.
  //
  //   The REC defines the following elements to be "space-like":
  //   * an mstyle, mphantom, or mpadded element, all of whose direct
  //     sub-expressions are space-like;
  //   * an mrow all of whose direct sub-expressions are space-like.
  //
  // 2) whether all but one child of the mrow-like element are space-like and
  //    this non-space-like child is an embellished operator.
  //
  //   The REC defines the following elements to be embellished operators:
  //   * one of the elements mstyle, mphantom, or mpadded, such that an mrow
  //     containing the same arguments would be an embellished operator;
  //   * an mrow whose arguments consist (in any order) of one embellished
  //     operator and zero or more space-like elements.
  //
  nsIFrame *childFrame, *baseFrame;
  bool embellishedOpFound = false;
  nsEmbellishData embellishData;
  
  for (childFrame = GetFirstPrincipalChild();
       childFrame;
       childFrame = childFrame->GetNextSibling()) {
    nsIMathMLFrame* mathMLFrame = do_QueryFrame(childFrame);
    if (!mathMLFrame) break;
    if (!mathMLFrame->IsSpaceLike()) {
      if (embellishedOpFound) break;
      baseFrame = childFrame;
      GetEmbellishDataFrom(baseFrame, embellishData);
      if (!NS_MATHML_IS_EMBELLISH_OPERATOR(embellishData.flags)) break;
      embellishedOpFound = true;
    }
  }

  if (!childFrame) {
    // we successfully went to the end of the loop. This means that one of
    // condition 1) or 2) holds.
    if (!embellishedOpFound) {
      // the mrow-like element is space-like.
      mPresentationData.flags |= NS_MATHML_SPACE_LIKE;
    } else {
      // the mrow-like element is an embellished operator.
      // let the state of the embellished operator found bubble to us.
      mPresentationData.baseFrame = baseFrame;
      mEmbellishData = embellishData;
    }
  }

  if (childFrame || !embellishedOpFound) {
    // The element is not embellished operator
    mPresentationData.baseFrame = nullptr;
    mEmbellishData.flags = 0;
    mEmbellishData.coreFrame = nullptr;
    mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;
    mEmbellishData.leadingSpace = 0;
    mEmbellishData.trailingSpace = 0;
  }

  if (childFrame || embellishedOpFound) {
    // The element is not space-like
    mPresentationData.flags &= ~NS_MATHML_SPACE_LIKE;
  }

  return NS_OK;
}

nsresult
nsMathMLContainerFrame::ReportErrorToConsole(const char*       errorMsgId,
                                             const PRUnichar** aParams,
                                             uint32_t          aParamCount)
{
  return nsContentUtils::ReportToConsole(nsIScriptError::errorFlag,
                                         "MathML", mContent->OwnerDoc(),
                                         nsContentUtils::eMATHML_PROPERTIES,
                                         errorMsgId, aParams, aParamCount);
}

nsresult
nsMathMLContainerFrame::ReportParseError(const PRUnichar* aAttribute,
                                         const PRUnichar* aValue)
{
  const PRUnichar* argv[] = 
    { aValue, aAttribute, mContent->Tag()->GetUTF16String() };
  return ReportErrorToConsole("AttributeParsingError", argv, 3);
}

nsresult
nsMathMLContainerFrame::ReportChildCountError()
{
  const PRUnichar* arg = mContent->Tag()->GetUTF16String();
  return ReportErrorToConsole("ChildCountIncorrect", &arg, 1);
}

//==========================

nsIFrame*
NS_NewMathMLmathBlockFrame(nsIPresShell* aPresShell, nsStyleContext* aContext,
                           uint32_t aFlags)
{
  nsMathMLmathBlockFrame* it = new (aPresShell) nsMathMLmathBlockFrame(aContext);
  if (it) {
    it->SetFlags(aFlags);
  }
  return it;
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmathBlockFrame)

nsIFrame*
NS_NewMathMLmathInlineFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsMathMLmathInlineFrame(aContext);
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmathInlineFrame)