Adding upstream version 110.0.1.upstream/110.0.1upstream

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

1 files changed, 1219 insertions, 0 deletions

diff --git a/layout/mathml/nsMathMLmtableFrame.cpp b/layout/mathml/nsMathMLmtableFrame.cpp
new file mode 100644
index 0000000000..449114c494
--- /dev/null
+++ b/layout/mathml/nsMathMLmtableFrame.cpp
@@ -0,0 +1,1219 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gfxContext.h"
+#include "nsMathMLmtableFrame.h"
+#include "nsPresContext.h"
+#include "nsStyleConsts.h"
+#include "nsNameSpaceManager.h"
+#include "nsCSSRendering.h"
+#include "mozilla/dom/MathMLElement.h"
+
+#include "nsCRT.h"
+#include "nsTArray.h"
+#include "nsTableFrame.h"
+#include "celldata.h"
+
+#include "mozilla/PresShell.h"
+#include "mozilla/RestyleManager.h"
+#include <algorithm>
+
+#include "nsIScriptError.h"
+#include "nsContentUtils.h"
+#include "nsLayoutUtils.h"
+
+using namespace mozilla;
+using namespace mozilla::image;
+using mozilla::dom::Element;
+
+//
+// <mtable> -- table or matrix - implementation
+//
+
+static int8_t ParseStyleValue(nsAtom* aAttribute,
+                              const nsAString& aAttributeValue) {
+  if (aAttribute == nsGkAtoms::rowalign_) {
+    if (aAttributeValue.EqualsLiteral("top")) {
+      return static_cast<int8_t>(StyleVerticalAlignKeyword::Top);
+    }
+    if (aAttributeValue.EqualsLiteral("bottom")) {
+      return static_cast<int8_t>(StyleVerticalAlignKeyword::Bottom);
+    }
+    if (aAttributeValue.EqualsLiteral("center")) {
+      return static_cast<int8_t>(StyleVerticalAlignKeyword::Middle);
+    }
+    return static_cast<int8_t>(StyleVerticalAlignKeyword::Baseline);
+  }
+
+  if (aAttribute == nsGkAtoms::columnalign_) {
+    if (aAttributeValue.EqualsLiteral("left")) {
+      return int8_t(StyleTextAlign::Left);
+    }
+    if (aAttributeValue.EqualsLiteral("right")) {
+      return int8_t(StyleTextAlign::Right);
+    }
+    return int8_t(StyleTextAlign::Center);
+  }
+
+  if (aAttribute == nsGkAtoms::rowlines_ ||
+      aAttribute == nsGkAtoms::columnlines_) {
+    if (aAttributeValue.EqualsLiteral("solid")) {
+      return static_cast<int8_t>(StyleBorderStyle::Solid);
+    }
+    if (aAttributeValue.EqualsLiteral("dashed")) {
+      return static_cast<int8_t>(StyleBorderStyle::Dashed);
+    }
+    return static_cast<int8_t>(StyleBorderStyle::None);
+  }
+
+  MOZ_CRASH("Unrecognized attribute.");
+  return -1;
+}
+
+static nsTArray<int8_t>* ExtractStyleValues(const nsAString& aString,
+                                            nsAtom* aAttribute,
+                                            bool aAllowMultiValues) {
+  nsTArray<int8_t>* styleArray = nullptr;
+
+  const char16_t* start = aString.BeginReading();
+  const char16_t* end = aString.EndReading();
+
+  int32_t startIndex = 0;
+  int32_t count = 0;
+
+  while (start < end) {
+    // Skip leading spaces.
+    while ((start < end) && nsCRT::IsAsciiSpace(*start)) {
+      start++;
+      startIndex++;
+    }
+
+    // Look for the end of the string, or another space.
+    while ((start < end) && !nsCRT::IsAsciiSpace(*start)) {
+      start++;
+      count++;
+    }
+
+    // Grab the value found and process it.
+    if (count > 0) {
+      if (!styleArray) styleArray = new nsTArray<int8_t>();
+
+      // We want to return a null array if an attribute gives multiple values,
+      // but multiple values aren't allowed.
+      if (styleArray->Length() > 1 && !aAllowMultiValues) {
+        delete styleArray;
+        return nullptr;
+      }
+
+      nsDependentSubstring valueString(aString, startIndex, count);
+      int8_t styleValue = ParseStyleValue(aAttribute, valueString);
+      styleArray->AppendElement(styleValue);
+
+      startIndex += count;
+      count = 0;
+    }
+  }
+  return styleArray;
+}
+
+static nsresult ReportParseError(nsIFrame* aFrame, const char16_t* aAttribute,
+                                 const char16_t* aValue) {
+  nsIContent* content = aFrame->GetContent();
+
+  AutoTArray<nsString, 3> params;
+  params.AppendElement(aValue);
+  params.AppendElement(aAttribute);
+  params.AppendElement(nsDependentAtomString(content->NodeInfo()->NameAtom()));
+
+  return nsContentUtils::ReportToConsole(
+      nsIScriptError::errorFlag, "Layout: MathML"_ns, content->OwnerDoc(),
+      nsContentUtils::eMATHML_PROPERTIES, "AttributeParsingError", params);
+}
+
+// Each rowalign='top bottom' or columnalign='left right center' (from
+// <mtable> or <mtr>) is split once into an nsTArray<int8_t> which is
+// stored in the property table. Row/Cell frames query the property table
+// to see what values apply to them.
+
+NS_DECLARE_FRAME_PROPERTY_DELETABLE(RowAlignProperty, nsTArray<int8_t>)
+NS_DECLARE_FRAME_PROPERTY_DELETABLE(RowLinesProperty, nsTArray<int8_t>)
+NS_DECLARE_FRAME_PROPERTY_DELETABLE(ColumnAlignProperty, nsTArray<int8_t>)
+NS_DECLARE_FRAME_PROPERTY_DELETABLE(ColumnLinesProperty, nsTArray<int8_t>)
+
+static const FramePropertyDescriptor<nsTArray<int8_t>>* AttributeToProperty(
+    nsAtom* aAttribute) {
+  if (aAttribute == nsGkAtoms::rowalign_) return RowAlignProperty();
+  if (aAttribute == nsGkAtoms::rowlines_) return RowLinesProperty();
+  if (aAttribute == nsGkAtoms::columnalign_) return ColumnAlignProperty();
+  NS_ASSERTION(aAttribute == nsGkAtoms::columnlines_, "Invalid attribute");
+  return ColumnLinesProperty();
+}
+
+/* This method looks for a property that applies to a cell, but it looks
+ * recursively because some cell properties can come from the cell, a row,
+ * a table, etc. This function searches through the hierarchy for a property
+ * and returns its value. The function stops searching after checking a <mtable>
+ * frame.
+ */
+static nsTArray<int8_t>* FindCellProperty(
+    const nsIFrame* aCellFrame,
+    const FramePropertyDescriptor<nsTArray<int8_t>>* aFrameProperty) {
+  const nsIFrame* currentFrame = aCellFrame;
+  nsTArray<int8_t>* propertyData = nullptr;
+
+  while (currentFrame) {
+    propertyData = currentFrame->GetProperty(aFrameProperty);
+    bool frameIsTable = (currentFrame->IsTableFrame());
+
+    if (propertyData || frameIsTable)
+      currentFrame = nullptr;  // A null frame pointer exits the loop
+    else
+      currentFrame = currentFrame->GetParent();  // Go to the parent frame
+  }
+
+  return propertyData;
+}
+
+static void ApplyBorderToStyle(const nsMathMLmtdFrame* aFrame,
+                               nsStyleBorder& aStyleBorder) {
+  uint32_t rowIndex = aFrame->RowIndex();
+  uint32_t columnIndex = aFrame->ColIndex();
+
+  nscoord borderWidth = nsPresContext::CSSPixelsToAppUnits(1);
+
+  nsTArray<int8_t>* rowLinesList = FindCellProperty(aFrame, RowLinesProperty());
+
+  nsTArray<int8_t>* columnLinesList =
+      FindCellProperty(aFrame, ColumnLinesProperty());
+
+  // We don't place a row line on top of the first row
+  if (rowIndex > 0 && rowLinesList) {
+    // If the row number is greater than the number of provided rowline
+    // values, we simply repeat the last value.
+    uint32_t listLength = rowLinesList->Length();
+    if (rowIndex < listLength) {
+      aStyleBorder.SetBorderStyle(
+          eSideTop,
+          static_cast<StyleBorderStyle>(rowLinesList->ElementAt(rowIndex - 1)));
+    } else {
+      aStyleBorder.SetBorderStyle(eSideTop,
+                                  static_cast<StyleBorderStyle>(
+                                      rowLinesList->ElementAt(listLength - 1)));
+    }
+    aStyleBorder.SetBorderWidth(eSideTop, borderWidth);
+  }
+
+  // We don't place a column line on the left of the first column.
+  if (columnIndex > 0 && columnLinesList) {
+    // If the column number is greater than the number of provided columline
+    // values, we simply repeat the last value.
+    uint32_t listLength = columnLinesList->Length();
+    if (columnIndex < listLength) {
+      aStyleBorder.SetBorderStyle(
+          eSideLeft, static_cast<StyleBorderStyle>(
+                         columnLinesList->ElementAt(columnIndex - 1)));
+    } else {
+      aStyleBorder.SetBorderStyle(
+          eSideLeft, static_cast<StyleBorderStyle>(
+                         columnLinesList->ElementAt(listLength - 1)));
+    }
+    aStyleBorder.SetBorderWidth(eSideLeft, borderWidth);
+  }
+}
+
+static nsMargin ComputeBorderOverflow(nsMathMLmtdFrame* aFrame,
+                                      const nsStyleBorder& aStyleBorder) {
+  nsMargin overflow;
+  int32_t rowIndex;
+  int32_t columnIndex;
+  nsTableFrame* table = aFrame->GetTableFrame();
+  aFrame->GetCellIndexes(rowIndex, columnIndex);
+  if (!columnIndex) {
+    overflow.left = table->GetColSpacing(-1);
+    overflow.right = table->GetColSpacing(0) / 2;
+  } else if (columnIndex == table->GetColCount() - 1) {
+    overflow.left = table->GetColSpacing(columnIndex - 1) / 2;
+    overflow.right = table->GetColSpacing(columnIndex + 1);
+  } else {
+    overflow.left = table->GetColSpacing(columnIndex - 1) / 2;
+    overflow.right = table->GetColSpacing(columnIndex) / 2;
+  }
+  if (!rowIndex) {
+    overflow.top = table->GetRowSpacing(-1);
+    overflow.bottom = table->GetRowSpacing(0) / 2;
+  } else if (rowIndex == table->GetRowCount() - 1) {
+    overflow.top = table->GetRowSpacing(rowIndex - 1) / 2;
+    overflow.bottom = table->GetRowSpacing(rowIndex + 1);
+  } else {
+    overflow.top = table->GetRowSpacing(rowIndex - 1) / 2;
+    overflow.bottom = table->GetRowSpacing(rowIndex) / 2;
+  }
+  return overflow;
+}
+
+/*
+ * A variant of the nsDisplayBorder contains special code to render a border
+ * around a nsMathMLmtdFrame based on the rowline and columnline properties
+ * set on the cell frame.
+ */
+class nsDisplaymtdBorder final : public nsDisplayBorder {
+ public:
+  nsDisplaymtdBorder(nsDisplayListBuilder* aBuilder, nsMathMLmtdFrame* aFrame)
+      : nsDisplayBorder(aBuilder, aFrame) {}
+
+  virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
+                           bool* aSnap) const override {
+    *aSnap = true;
+    nsStyleBorder styleBorder = *mFrame->StyleBorder();
+    nsMathMLmtdFrame* frame = static_cast<nsMathMLmtdFrame*>(mFrame);
+    ApplyBorderToStyle(frame, styleBorder);
+    nsRect bounds = CalculateBounds<nsRect>(styleBorder);
+    nsMargin overflow = ComputeBorderOverflow(frame, styleBorder);
+    bounds.Inflate(overflow);
+    return bounds;
+  }
+
+  virtual void Paint(nsDisplayListBuilder* aBuilder,
+                     gfxContext* aCtx) override {
+    nsStyleBorder styleBorder = *mFrame->StyleBorder();
+    nsMathMLmtdFrame* frame = static_cast<nsMathMLmtdFrame*>(mFrame);
+    ApplyBorderToStyle(frame, styleBorder);
+
+    nsRect bounds = nsRect(ToReferenceFrame(), mFrame->GetSize());
+    nsMargin overflow = ComputeBorderOverflow(frame, styleBorder);
+    bounds.Inflate(overflow);
+
+    PaintBorderFlags flags = aBuilder->ShouldSyncDecodeImages()
+                                 ? PaintBorderFlags::SyncDecodeImages
+                                 : PaintBorderFlags();
+
+    Unused << nsCSSRendering::PaintBorderWithStyleBorder(
+        mFrame->PresContext(), *aCtx, mFrame, GetPaintRect(aBuilder, aCtx),
+        bounds, styleBorder, mFrame->Style(), flags, mFrame->GetSkipSides());
+  }
+
+  bool CreateWebRenderCommands(
+      mozilla::wr::DisplayListBuilder& aBuilder,
+      mozilla::wr::IpcResourceUpdateQueue& aResources,
+      const StackingContextHelper& aSc,
+      mozilla::layers::RenderRootStateManager* aManager,
+      nsDisplayListBuilder* aDisplayListBuilder) override {
+    return false;
+  }
+
+  virtual bool IsInvisibleInRect(const nsRect& aRect) const override {
+    return false;
+  }
+};
+
+#ifdef DEBUG
+#  define DEBUG_VERIFY_THAT_FRAME_IS(_frame, _expected)                       \
+    MOZ_ASSERT(                                                               \
+        mozilla::StyleDisplay::_expected == _frame->StyleDisplay()->mDisplay, \
+        "internal error");
+#else
+#  define DEBUG_VERIFY_THAT_FRAME_IS(_frame, _expected)
+#endif
+
+static void ParseFrameAttribute(nsIFrame* aFrame, nsAtom* aAttribute,
+                                bool aAllowMultiValues) {
+  nsAutoString attrValue;
+
+  Element* frameElement = aFrame->GetContent()->AsElement();
+  frameElement->GetAttr(kNameSpaceID_None, aAttribute, attrValue);
+
+  if (!attrValue.IsEmpty()) {
+    nsTArray<int8_t>* valueList =
+        ExtractStyleValues(attrValue, aAttribute, aAllowMultiValues);
+
+    // If valueList is null, that indicates a problem with the attribute value.
+    // Only set properties on a valid attribute value.
+    if (valueList) {
+      // The code reading the property assumes that this list is nonempty.
+      NS_ASSERTION(valueList->Length() >= 1, "valueList should not be empty!");
+      aFrame->SetProperty(AttributeToProperty(aAttribute), valueList);
+    } else {
+      ReportParseError(aFrame, aAttribute->GetUTF16String(), attrValue.get());
+    }
+  }
+}
+
+// rowspacing
+//
+// Specifies the distance between successive rows in an mtable.  Multiple
+// lengths can be specified, each corresponding to its respective position
+// between rows.  For example:
+//
+// [ROW_0]
+// rowspace_0
+// [ROW_1]
+// rowspace_1
+// [ROW_2]
+//
+// If the number of row gaps exceeds the number of lengths specified, the final
+// specified length is repeated.  Additional lengths are ignored.
+//
+// values: (length)+
+// default: 1.0ex
+//
+// Unitless values are permitted and provide a multiple of the default value
+// Negative values are forbidden.
+//
+
+// columnspacing
+//
+// Specifies the distance between successive columns in an mtable.  Multiple
+// lengths can be specified, each corresponding to its respective position
+// between columns.  For example:
+//
+// [COLUMN_0] columnspace_0 [COLUMN_1] columnspace_1 [COLUMN_2]
+//
+// If the number of column gaps exceeds the number of lengths specified, the
+// final specified length is repeated.  Additional lengths are ignored.
+//
+// values: (length)+
+// default: 0.8em
+//
+// Unitless values are permitted and provide a multiple of the default value
+// Negative values are forbidden.
+//
+
+// framespacing
+//
+// Specifies the distance between the mtable and its frame (if any).  The
+// first value specified provides the spacing between the left and right edge
+// of the table and the frame, the second value determines the spacing between
+// the top and bottom edges and the frame.
+//
+// An error is reported if only one length is passed.  Any additional lengths
+// are ignored
+//
+// values: length length
+// default: 0em   0ex    If frame attribute is "none" or not specified,
+//          0.4em 0.5ex  otherwise
+//
+// Unitless values are permitted and provide a multiple of the default value
+// Negative values are forbidden.
+//
+
+static const float kDefaultRowspacingEx = 1.0f;
+static const float kDefaultColumnspacingEm = 0.8f;
+static const float kDefaultFramespacingArg0Em = 0.4f;
+static const float kDefaultFramespacingArg1Ex = 0.5f;
+
+static void ExtractSpacingValues(const nsAString& aString, nsAtom* aAttribute,
+                                 nsTArray<nscoord>& aSpacingArray,
+                                 nsIFrame* aFrame, nscoord aDefaultValue0,
+                                 nscoord aDefaultValue1,
+                                 float aFontSizeInflation) {
+  nsPresContext* presContext = aFrame->PresContext();
+  ComputedStyle* computedStyle = aFrame->Style();
+
+  const char16_t* start = aString.BeginReading();
+  const char16_t* end = aString.EndReading();
+
+  int32_t startIndex = 0;
+  int32_t count = 0;
+  int32_t elementNum = 0;
+
+  while (start < end) {
+    // Skip leading spaces.
+    while ((start < end) && nsCRT::IsAsciiSpace(*start)) {
+      start++;
+      startIndex++;
+    }
+
+    // Look for the end of the string, or another space.
+    while ((start < end) && !nsCRT::IsAsciiSpace(*start)) {
+      start++;
+      count++;
+    }
+
+    // Grab the value found and process it.
+    if (count > 0) {
+      const nsAString& str = Substring(aString, startIndex, count);
+      nsAutoString valueString;
+      valueString.Assign(str);
+      nscoord newValue;
+      if (aAttribute == nsGkAtoms::framespacing_ && elementNum) {
+        newValue = aDefaultValue1;
+      } else {
+        newValue = aDefaultValue0;
+      }
+      nsMathMLFrame::ParseNumericValue(valueString, &newValue, 0, presContext,
+                                       computedStyle, aFontSizeInflation);
+      aSpacingArray.AppendElement(newValue);
+
+      startIndex += count;
+      count = 0;
+      elementNum++;
+    }
+  }
+}
+
+static void ParseSpacingAttribute(nsMathMLmtableFrame* aFrame,
+                                  nsAtom* aAttribute) {
+  NS_ASSERTION(aAttribute == nsGkAtoms::rowspacing_ ||
+                   aAttribute == nsGkAtoms::columnspacing_ ||
+                   aAttribute == nsGkAtoms::framespacing_,
+               "Non spacing attribute passed");
+
+  nsAutoString attrValue;
+  Element* frameElement = aFrame->GetContent()->AsElement();
+  frameElement->GetAttr(kNameSpaceID_None, aAttribute, attrValue);
+
+  if (nsGkAtoms::framespacing_ == aAttribute) {
+    nsAutoString frame;
+    frameElement->GetAttr(kNameSpaceID_None, nsGkAtoms::frame, frame);
+    if (frame.IsEmpty() || frame.EqualsLiteral("none")) {
+      aFrame->SetFrameSpacing(0, 0);
+      return;
+    }
+  }
+
+  nscoord value;
+  nscoord value2;
+  // Set defaults
+  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(aFrame);
+  RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetFontMetricsForFrame(aFrame, fontSizeInflation);
+  if (nsGkAtoms::rowspacing_ == aAttribute) {
+    value = kDefaultRowspacingEx * fm->XHeight();
+    value2 = 0;
+  } else if (nsGkAtoms::columnspacing_ == aAttribute) {
+    value = kDefaultColumnspacingEm * fm->EmHeight();
+    value2 = 0;
+  } else {
+    value = kDefaultFramespacingArg0Em * fm->EmHeight();
+    value2 = kDefaultFramespacingArg1Ex * fm->XHeight();
+  }
+
+  nsTArray<nscoord> valueList;
+  ExtractSpacingValues(attrValue, aAttribute, valueList, aFrame, value, value2,
+                       fontSizeInflation);
+  if (valueList.Length() == 0) {
+    if (frameElement->HasAttr(kNameSpaceID_None, aAttribute)) {
+      ReportParseError(aFrame, aAttribute->GetUTF16String(), attrValue.get());
+    }
+    valueList.AppendElement(value);
+  }
+  if (aAttribute == nsGkAtoms::framespacing_) {
+    if (valueList.Length() == 1) {
+      if (frameElement->HasAttr(kNameSpaceID_None, aAttribute)) {
+        ReportParseError(aFrame, aAttribute->GetUTF16String(), attrValue.get());
+      }
+      valueList.AppendElement(value2);
+    } else if (valueList.Length() != 2) {
+      ReportParseError(aFrame, aAttribute->GetUTF16String(), attrValue.get());
+    }
+  }
+
+  if (aAttribute == nsGkAtoms::rowspacing_) {
+    aFrame->SetRowSpacingArray(valueList);
+  } else if (aAttribute == nsGkAtoms::columnspacing_) {
+    aFrame->SetColSpacingArray(valueList);
+  } else {
+    aFrame->SetFrameSpacing(valueList.ElementAt(0), valueList.ElementAt(1));
+  }
+}
+
+static void ParseSpacingAttributes(nsMathMLmtableFrame* aTableFrame) {
+  ParseSpacingAttribute(aTableFrame, nsGkAtoms::rowspacing_);
+  ParseSpacingAttribute(aTableFrame, nsGkAtoms::columnspacing_);
+  ParseSpacingAttribute(aTableFrame, nsGkAtoms::framespacing_);
+  aTableFrame->SetUseCSSSpacing();
+}
+
+// map all attributes within a table -- requires the indices of rows and cells.
+// so it can only happen after they are made ready by the table base class.
+static void MapAllAttributesIntoCSS(nsMathMLmtableFrame* aTableFrame) {
+  // Map mtable rowalign & rowlines.
+  ParseFrameAttribute(aTableFrame, nsGkAtoms::rowalign_, true);
+  ParseFrameAttribute(aTableFrame, nsGkAtoms::rowlines_, true);
+
+  // Map mtable columnalign & columnlines.
+  ParseFrameAttribute(aTableFrame, nsGkAtoms::columnalign_, true);
+  ParseFrameAttribute(aTableFrame, nsGkAtoms::columnlines_, true);
+
+  // Map mtable rowspacing, columnspacing & framespacing
+  ParseSpacingAttributes(aTableFrame);
+
+  // mtable is simple and only has one (pseudo) row-group
+  nsIFrame* rgFrame = aTableFrame->PrincipalChildList().FirstChild();
+  if (!rgFrame || !rgFrame->IsTableRowGroupFrame()) return;
+
+  for (nsIFrame* rowFrame : rgFrame->PrincipalChildList()) {
+    DEBUG_VERIFY_THAT_FRAME_IS(rowFrame, TableRow);
+    if (rowFrame->IsTableRowFrame()) {
+      // Map row rowalign.
+      ParseFrameAttribute(rowFrame, nsGkAtoms::rowalign_, false);
+      // Map row columnalign.
+      ParseFrameAttribute(rowFrame, nsGkAtoms::columnalign_, true);
+
+      for (nsIFrame* cellFrame : rowFrame->PrincipalChildList()) {
+        DEBUG_VERIFY_THAT_FRAME_IS(cellFrame, TableCell);
+        if (cellFrame->IsTableCellFrame()) {
+          // Map cell rowalign.
+          ParseFrameAttribute(cellFrame, nsGkAtoms::rowalign_, false);
+          // Map row columnalign.
+          ParseFrameAttribute(cellFrame, nsGkAtoms::columnalign_, false);
+        }
+      }
+    }
+  }
+}
+
+// the align attribute of mtable can have a row number which indicates
+// from where to anchor the table, e.g., top 5 means anchor the table at
+// the top of the 5th row, axis -1 means anchor the table on the axis of
+// the last row
+
+// The REC says that the syntax is
+// '\s*(top|bottom|center|baseline|axis)(\s+-?[0-9]+)?\s*'
+// the parsing could have been simpler with that syntax
+// but for backward compatibility we make optional
+// the whitespaces between the alignment name and the row number
+
+enum eAlign {
+  eAlign_top,
+  eAlign_bottom,
+  eAlign_center,
+  eAlign_baseline,
+  eAlign_axis
+};
+
+static void ParseAlignAttribute(nsString& aValue, eAlign& aAlign,
+                                int32_t& aRowIndex) {
+  // by default, the table is centered about the axis
+  aRowIndex = 0;
+  aAlign = eAlign_axis;
+  int32_t len = 0;
+
+  // we only have to remove the leading spaces because
+  // ToInteger ignores the whitespaces around the number
+  aValue.CompressWhitespace(true, false);
+
+  if (0 == aValue.Find(u"top")) {
+    len = 3;  // 3 is the length of 'top'
+    aAlign = eAlign_top;
+  } else if (0 == aValue.Find(u"bottom")) {
+    len = 6;  // 6 is the length of 'bottom'
+    aAlign = eAlign_bottom;
+  } else if (0 == aValue.Find(u"center")) {
+    len = 6;  // 6 is the length of 'center'
+    aAlign = eAlign_center;
+  } else if (0 == aValue.Find(u"baseline")) {
+    len = 8;  // 8 is the length of 'baseline'
+    aAlign = eAlign_baseline;
+  } else if (0 == aValue.Find(u"axis")) {
+    len = 4;  // 4 is the length of 'axis'
+    aAlign = eAlign_axis;
+  }
+  if (len) {
+    nsresult error;
+    aValue.Cut(0, len);  // aValue is not a const here
+    aRowIndex = aValue.ToInteger(&error);
+    if (NS_FAILED(error)) aRowIndex = 0;
+  }
+}
+
+#ifdef DEBUG_rbs_off
+// call ListMathMLTree(mParent) to get the big picture
+static void ListMathMLTree(nsIFrame* atLeast) {
+  // climb up to <math> or <body> if <math> isn't there
+  nsIFrame* f = atLeast;
+  for (; f; f = f->GetParent()) {
+    nsIContent* c = f->GetContent();
+    if (!c || c->IsMathMLElement(nsGkAtoms::math) ||
+        // XXXbaku which kind of body tag?
+        c->NodeInfo()->NameAtom(nsGkAtoms::body))
+      break;
+  }
+  if (!f) f = atLeast;
+  f->List(stdout, 0);
+}
+#endif
+
+// --------
+// implementation of nsMathMLmtableWrapperFrame
+
+NS_QUERYFRAME_HEAD(nsMathMLmtableWrapperFrame)
+  NS_QUERYFRAME_ENTRY(nsIMathMLFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsTableWrapperFrame)
+
+nsContainerFrame* NS_NewMathMLmtableOuterFrame(PresShell* aPresShell,
+                                               ComputedStyle* aStyle) {
+  return new (aPresShell)
+      nsMathMLmtableWrapperFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmtableWrapperFrame)
+
+nsMathMLmtableWrapperFrame::~nsMathMLmtableWrapperFrame() = default;
+
+nsresult nsMathMLmtableWrapperFrame::AttributeChanged(int32_t aNameSpaceID,
+                                                      nsAtom* aAttribute,
+                                                      int32_t aModType) {
+  // Attributes specific to <mtable>:
+  // frame         : in mathml.css
+  // framespacing  : here
+  // groupalign    : not yet supported
+  // equalrows     : not yet supported
+  // equalcolumns  : not yet supported
+  // displaystyle  : here and in mathml.css
+  // align         : in reflow
+  // rowalign      : here
+  // rowlines      : here
+  // rowspacing    : here
+  // columnalign   : here
+  // columnlines   : here
+  // columnspacing : here
+
+  // mtable is simple and only has one (pseudo) row-group inside our inner-table
+  nsIFrame* tableFrame = mFrames.FirstChild();
+  NS_ASSERTION(tableFrame && tableFrame->IsTableFrame(),
+               "should always have an inner table frame");
+  nsIFrame* rgFrame = tableFrame->PrincipalChildList().FirstChild();
+  if (!rgFrame || !rgFrame->IsTableRowGroupFrame()) return NS_OK;
+
+  // align - just need to issue a dirty (resize) reflow command
+  if (aAttribute == nsGkAtoms::align) {
+    PresShell()->FrameNeedsReflow(this, IntrinsicDirty::None,
+                                  NS_FRAME_IS_DIRTY);
+    return NS_OK;
+  }
+
+  // displaystyle - may seem innocuous, but it is actually very harsh --
+  // like changing an unit. Blow away and recompute all our automatic
+  // presentational data, and issue a style-changed reflow request
+  if (aAttribute == nsGkAtoms::displaystyle_) {
+    nsMathMLContainerFrame::RebuildAutomaticDataForChildren(GetParent());
+    // Need to reflow the parent, not us, because this can actually
+    // affect siblings.
+    PresShell()->FrameNeedsReflow(GetParent(),
+                                  IntrinsicDirty::FrameAncestorsAndDescendants,
+                                  NS_FRAME_IS_DIRTY);
+    return NS_OK;
+  }
+
+  // ...and the other attributes affect rows or columns in one way or another
+
+  nsPresContext* presContext = tableFrame->PresContext();
+  if (aAttribute == nsGkAtoms::rowspacing_ ||
+      aAttribute == nsGkAtoms::columnspacing_ ||
+      aAttribute == nsGkAtoms::framespacing_) {
+    nsMathMLmtableFrame* mathMLmtableFrame = do_QueryFrame(tableFrame);
+    if (mathMLmtableFrame) {
+      ParseSpacingAttribute(mathMLmtableFrame, aAttribute);
+      mathMLmtableFrame->SetUseCSSSpacing();
+    }
+  } else if (aAttribute == nsGkAtoms::rowalign_ ||
+             aAttribute == nsGkAtoms::rowlines_ ||
+             aAttribute == nsGkAtoms::columnalign_ ||
+             aAttribute == nsGkAtoms::columnlines_) {
+    // clear any cached property list for this table
+    tableFrame->RemoveProperty(AttributeToProperty(aAttribute));
+    // Reparse the new attribute on the table.
+    ParseFrameAttribute(tableFrame, aAttribute, true);
+  } else {
+    // Ignore attributes that do not affect layout.
+    return NS_OK;
+  }
+
+  // Explicitly request a reflow in our subtree to pick up any changes
+  presContext->PresShell()->FrameNeedsReflow(
+      this, IntrinsicDirty::FrameAncestorsAndDescendants, NS_FRAME_IS_DIRTY);
+
+  return NS_OK;
+}
+
+nsIFrame* nsMathMLmtableWrapperFrame::GetRowFrameAt(int32_t aRowIndex) {
+  int32_t rowCount = GetRowCount();
+
+  // Negative indices mean to find upwards from the end.
+  if (aRowIndex < 0) {
+    aRowIndex = rowCount + aRowIndex;
+  } else {
+    // aRowIndex is 1-based, so convert it to a 0-based index
+    --aRowIndex;
+  }
+
+  // if our inner table says that the index is valid, find the row now
+  if (0 <= aRowIndex && aRowIndex <= rowCount) {
+    nsIFrame* tableFrame = mFrames.FirstChild();
+    NS_ASSERTION(tableFrame && tableFrame->IsTableFrame(),
+                 "should always have an inner table frame");
+    nsIFrame* rgFrame = tableFrame->PrincipalChildList().FirstChild();
+    if (!rgFrame || !rgFrame->IsTableRowGroupFrame()) return nullptr;
+    for (nsIFrame* rowFrame : rgFrame->PrincipalChildList()) {
+      if (aRowIndex == 0) {
+        DEBUG_VERIFY_THAT_FRAME_IS(rowFrame, TableRow);
+        if (!rowFrame->IsTableRowFrame()) return nullptr;
+
+        return rowFrame;
+      }
+      --aRowIndex;
+    }
+  }
+  return nullptr;
+}
+
+void nsMathMLmtableWrapperFrame::Reflow(nsPresContext* aPresContext,
+                                        ReflowOutput& aDesiredSize,
+                                        const ReflowInput& aReflowInput,
+                                        nsReflowStatus& aStatus) {
+  MOZ_ASSERT(aStatus.IsEmpty(), "Caller should pass a fresh reflow status!");
+
+  nsAutoString value;
+  // we want to return a table that is anchored according to the align attribute
+
+  nsTableWrapperFrame::Reflow(aPresContext, aDesiredSize, aReflowInput,
+                              aStatus);
+  NS_ASSERTION(aDesiredSize.Height() >= 0, "illegal height for mtable");
+  NS_ASSERTION(aDesiredSize.Width() >= 0, "illegal width for mtable");
+
+  // see if the user has set the align attribute on the <mtable>
+  int32_t rowIndex = 0;
+  eAlign tableAlign = eAlign_axis;
+  mContent->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::align, value);
+  if (!value.IsEmpty()) {
+    ParseAlignAttribute(value, tableAlign, rowIndex);
+  }
+
+  // adjustments if there is a specified row from where to anchor the table
+  // (conceptually: when there is no row of reference, picture the table as if
+  // it is wrapped in a single big fictional row at dy = 0, this way of
+  // doing so allows us to have a single code path for all cases).
+  nscoord dy = 0;
+  WritingMode wm = aDesiredSize.GetWritingMode();
+  nscoord blockSize = aDesiredSize.BSize(wm);
+  nsIFrame* rowFrame = nullptr;
+  if (rowIndex) {
+    rowFrame = GetRowFrameAt(rowIndex);
+    if (rowFrame) {
+      // translate the coordinates to be relative to us and in our writing mode
+      nsIFrame* frame = rowFrame;
+      LogicalRect rect(wm, frame->GetRect(),
+                       aReflowInput.ComputedSizeAsContainerIfConstrained());
+      blockSize = rect.BSize(wm);
+      do {
+        nsIFrame* parent = frame->GetParent();
+        dy += frame->BStart(wm, parent->GetSize());
+        frame = parent;
+      } while (frame != this);
+    }
+  }
+  switch (tableAlign) {
+    case eAlign_top:
+      aDesiredSize.SetBlockStartAscent(dy);
+      break;
+    case eAlign_bottom:
+      aDesiredSize.SetBlockStartAscent(dy + blockSize);
+      break;
+    case eAlign_center:
+      aDesiredSize.SetBlockStartAscent(dy + blockSize / 2);
+      break;
+    case eAlign_baseline:
+      if (rowFrame) {
+        // anchor the table on the baseline of the row of reference
+        nscoord rowAscent = ((nsTableRowFrame*)rowFrame)->GetMaxCellAscent();
+        if (rowAscent) {  // the row has at least one cell with 'vertical-align:
+                          // baseline'
+          aDesiredSize.SetBlockStartAscent(dy + rowAscent);
+          break;
+        }
+      }
+      // in other situations, fallback to center
+      aDesiredSize.SetBlockStartAscent(dy + blockSize / 2);
+      break;
+    case eAlign_axis:
+    default: {
+      // XXX should instead use style data from the row of reference here ?
+      RefPtr<nsFontMetrics> fm =
+          nsLayoutUtils::GetInflatedFontMetricsForFrame(this);
+      nscoord axisHeight;
+      GetAxisHeight(aReflowInput.mRenderingContext->GetDrawTarget(), fm,
+                    axisHeight);
+      if (rowFrame) {
+        // anchor the table on the axis of the row of reference
+        // XXX fallback to baseline because it is a hard problem
+        // XXX need to fetch the axis of the row; would need rowalign=axis to
+        // work better
+        nscoord rowAscent = ((nsTableRowFrame*)rowFrame)->GetMaxCellAscent();
+        if (rowAscent) {  // the row has at least one cell with 'vertical-align:
+                          // baseline'
+          aDesiredSize.SetBlockStartAscent(dy + rowAscent);
+          break;
+        }
+      }
+      // in other situations, fallback to using half of the height
+      aDesiredSize.SetBlockStartAscent(dy + blockSize / 2 + axisHeight);
+    }
+  }
+
+  mReference.x = 0;
+  mReference.y = aDesiredSize.BlockStartAscent();
+
+  // just make-up a bounding metrics
+  mBoundingMetrics = nsBoundingMetrics();
+  mBoundingMetrics.ascent = aDesiredSize.BlockStartAscent();
+  mBoundingMetrics.descent =
+      aDesiredSize.Height() - aDesiredSize.BlockStartAscent();
+  mBoundingMetrics.width = aDesiredSize.Width();
+  mBoundingMetrics.leftBearing = 0;
+  mBoundingMetrics.rightBearing = aDesiredSize.Width();
+
+  aDesiredSize.mBoundingMetrics = mBoundingMetrics;
+}
+
+nsContainerFrame* NS_NewMathMLmtableFrame(PresShell* aPresShell,
+                                          ComputedStyle* aStyle) {
+  return new (aPresShell)
+      nsMathMLmtableFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmtableFrame)
+
+nsMathMLmtableFrame::~nsMathMLmtableFrame() = default;
+
+void nsMathMLmtableFrame::SetInitialChildList(ChildListID aListID,
+                                              nsFrameList&& aChildList) {
+  nsTableFrame::SetInitialChildList(aListID, std::move(aChildList));
+  MapAllAttributesIntoCSS(this);
+}
+
+void nsMathMLmtableFrame::RestyleTable() {
+  // re-sync MathML specific style data that may have changed
+  MapAllAttributesIntoCSS(this);
+
+  // Explicitly request a re-resolve and reflow in our subtree to pick up any
+  // changes
+  PresContext()->RestyleManager()->PostRestyleEvent(
+      mContent->AsElement(), RestyleHint::RestyleSubtree(),
+      nsChangeHint_AllReflowHints);
+}
+
+nscoord nsMathMLmtableFrame::GetColSpacing(int32_t aColIndex) {
+  if (mUseCSSSpacing) {
+    return nsTableFrame::GetColSpacing(aColIndex);
+  }
+  if (!mColSpacing.Length()) {
+    NS_ERROR("mColSpacing should not be empty");
+    return 0;
+  }
+  if (aColIndex < 0 || aColIndex >= GetColCount()) {
+    NS_ASSERTION(aColIndex == -1 || aColIndex == GetColCount(),
+                 "Desired column beyond bounds of table and border");
+    return mFrameSpacingX;
+  }
+  if ((uint32_t)aColIndex >= mColSpacing.Length()) {
+    return mColSpacing.LastElement();
+  }
+  return mColSpacing.ElementAt(aColIndex);
+}
+
+nscoord nsMathMLmtableFrame::GetColSpacing(int32_t aStartColIndex,
+                                           int32_t aEndColIndex) {
+  if (mUseCSSSpacing) {
+    return nsTableFrame::GetColSpacing(aStartColIndex, aEndColIndex);
+  }
+  if (aStartColIndex == aEndColIndex) {
+    return 0;
+  }
+  if (!mColSpacing.Length()) {
+    NS_ERROR("mColSpacing should not be empty");
+    return 0;
+  }
+  nscoord space = 0;
+  if (aStartColIndex < 0) {
+    NS_ASSERTION(aStartColIndex == -1,
+                 "Desired column beyond bounds of table and border");
+    space += mFrameSpacingX;
+    aStartColIndex = 0;
+  }
+  if (aEndColIndex >= GetColCount()) {
+    NS_ASSERTION(aEndColIndex == GetColCount(),
+                 "Desired column beyond bounds of table and border");
+    space += mFrameSpacingX;
+    aEndColIndex = GetColCount();
+  }
+  // Only iterate over column spacing when there is the potential to vary
+  int32_t min = std::min(aEndColIndex, (int32_t)mColSpacing.Length());
+  for (int32_t i = aStartColIndex; i < min; i++) {
+    space += mColSpacing.ElementAt(i);
+  }
+  // The remaining values are constant.  Note that if there are more
+  // column spacings specified than there are columns, LastElement() will be
+  // multiplied by 0, so it is still safe to use.
+  space += (aEndColIndex - min) * mColSpacing.LastElement();
+  return space;
+}
+
+nscoord nsMathMLmtableFrame::GetRowSpacing(int32_t aRowIndex) {
+  if (mUseCSSSpacing) {
+    return nsTableFrame::GetRowSpacing(aRowIndex);
+  }
+  if (!mRowSpacing.Length()) {
+    NS_ERROR("mRowSpacing should not be empty");
+    return 0;
+  }
+  if (aRowIndex < 0 || aRowIndex >= GetRowCount()) {
+    NS_ASSERTION(aRowIndex == -1 || aRowIndex == GetRowCount(),
+                 "Desired row beyond bounds of table and border");
+    return mFrameSpacingY;
+  }
+  if ((uint32_t)aRowIndex >= mRowSpacing.Length()) {
+    return mRowSpacing.LastElement();
+  }
+  return mRowSpacing.ElementAt(aRowIndex);
+}
+
+nscoord nsMathMLmtableFrame::GetRowSpacing(int32_t aStartRowIndex,
+                                           int32_t aEndRowIndex) {
+  if (mUseCSSSpacing) {
+    return nsTableFrame::GetRowSpacing(aStartRowIndex, aEndRowIndex);
+  }
+  if (aStartRowIndex == aEndRowIndex) {
+    return 0;
+  }
+  if (!mRowSpacing.Length()) {
+    NS_ERROR("mRowSpacing should not be empty");
+    return 0;
+  }
+  nscoord space = 0;
+  if (aStartRowIndex < 0) {
+    NS_ASSERTION(aStartRowIndex == -1,
+                 "Desired row beyond bounds of table and border");
+    space += mFrameSpacingY;
+    aStartRowIndex = 0;
+  }
+  if (aEndRowIndex >= GetRowCount()) {
+    NS_ASSERTION(aEndRowIndex == GetRowCount(),
+                 "Desired row beyond bounds of table and border");
+    space += mFrameSpacingY;
+    aEndRowIndex = GetRowCount();
+  }
+  // Only iterate over row spacing when there is the potential to vary
+  int32_t min = std::min(aEndRowIndex, (int32_t)mRowSpacing.Length());
+  for (int32_t i = aStartRowIndex; i < min; i++) {
+    space += mRowSpacing.ElementAt(i);
+  }
+  // The remaining values are constant.  Note that if there are more
+  // row spacings specified than there are row, LastElement() will be
+  // multiplied by 0, so it is still safe to use.
+  space += (aEndRowIndex - min) * mRowSpacing.LastElement();
+  return space;
+}
+
+void nsMathMLmtableFrame::SetUseCSSSpacing() {
+  mUseCSSSpacing = !(mContent->AsElement()->HasAttr(kNameSpaceID_None,
+                                                    nsGkAtoms::rowspacing_) ||
+                     mContent->AsElement()->HasAttr(
+                         kNameSpaceID_None, nsGkAtoms::columnspacing_) ||
+                     mContent->AsElement()->HasAttr(kNameSpaceID_None,
+                                                    nsGkAtoms::framespacing_));
+}
+
+NS_QUERYFRAME_HEAD(nsMathMLmtableFrame)
+  NS_QUERYFRAME_ENTRY(nsMathMLmtableFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsTableFrame)
+
+// --------
+// implementation of nsMathMLmtrFrame
+
+nsContainerFrame* NS_NewMathMLmtrFrame(PresShell* aPresShell,
+                                       ComputedStyle* aStyle) {
+  return new (aPresShell)
+      nsMathMLmtrFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmtrFrame)
+
+nsMathMLmtrFrame::~nsMathMLmtrFrame() = default;
+
+nsresult nsMathMLmtrFrame::AttributeChanged(int32_t aNameSpaceID,
+                                            nsAtom* aAttribute,
+                                            int32_t aModType) {
+  // Attributes specific to <mtr>:
+  // groupalign  : Not yet supported.
+  // rowalign    : Here
+  // columnalign : Here
+
+  nsPresContext* presContext = PresContext();
+
+  if (aAttribute != nsGkAtoms::rowalign_ &&
+      aAttribute != nsGkAtoms::columnalign_) {
+    return NS_OK;
+  }
+
+  RemoveProperty(AttributeToProperty(aAttribute));
+
+  bool allowMultiValues = (aAttribute == nsGkAtoms::columnalign_);
+
+  // Reparse the new attribute.
+  ParseFrameAttribute(this, aAttribute, allowMultiValues);
+
+  // Explicitly request a reflow in our subtree to pick up any changes
+  presContext->PresShell()->FrameNeedsReflow(
+      this, IntrinsicDirty::FrameAncestorsAndDescendants, NS_FRAME_IS_DIRTY);
+
+  return NS_OK;
+}
+
+// --------
+// implementation of nsMathMLmtdFrame
+
+nsContainerFrame* NS_NewMathMLmtdFrame(PresShell* aPresShell,
+                                       ComputedStyle* aStyle,
+                                       nsTableFrame* aTableFrame) {
+  return new (aPresShell) nsMathMLmtdFrame(aStyle, aTableFrame);
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmtdFrame)
+
+nsMathMLmtdFrame::~nsMathMLmtdFrame() = default;
+
+void nsMathMLmtdFrame::Init(nsIContent* aContent, nsContainerFrame* aParent,
+                            nsIFrame* aPrevInFlow) {
+  nsTableCellFrame::Init(aContent, aParent, aPrevInFlow);
+
+  // We want to use the ancestor <math> element's font inflation to avoid
+  // individual cells having their own varying font inflation.
+  RemoveStateBits(NS_FRAME_FONT_INFLATION_FLOW_ROOT);
+}
+
+nsresult nsMathMLmtdFrame::AttributeChanged(int32_t aNameSpaceID,
+                                            nsAtom* aAttribute,
+                                            int32_t aModType) {
+  // Attributes specific to <mtd>:
+  // groupalign  : Not yet supported
+  // rowalign    : here
+  // columnalign : here
+  // rowspan     : here
+  // columnspan  : here
+
+  if (aAttribute == nsGkAtoms::rowalign_ ||
+      aAttribute == nsGkAtoms::columnalign_) {
+    RemoveProperty(AttributeToProperty(aAttribute));
+
+    // Reparse the attribute.
+    ParseFrameAttribute(this, aAttribute, false);
+    return NS_OK;
+  }
+
+  if (aAttribute == nsGkAtoms::rowspan ||
+      aAttribute == nsGkAtoms::columnspan_) {
+    // use the naming expected by the base class
+    if (aAttribute == nsGkAtoms::columnspan_) aAttribute = nsGkAtoms::colspan;
+    return nsTableCellFrame::AttributeChanged(aNameSpaceID, aAttribute,
+                                              aModType);
+  }
+
+  return NS_OK;
+}
+
+StyleVerticalAlignKeyword nsMathMLmtdFrame::GetVerticalAlign() const {
+  // Set the default alignment in case no alignment was specified
+  auto alignment = nsTableCellFrame::GetVerticalAlign();
+
+  nsTArray<int8_t>* alignmentList = FindCellProperty(this, RowAlignProperty());
+
+  if (alignmentList) {
+    uint32_t rowIndex = RowIndex();
+
+    // If the row number is greater than the number of provided rowalign values,
+    // we simply repeat the last value.
+    return static_cast<StyleVerticalAlignKeyword>(
+        (rowIndex < alignmentList->Length())
+            ? alignmentList->ElementAt(rowIndex)
+            : alignmentList->LastElement());
+  }
+
+  return alignment;
+}
+
+nsresult nsMathMLmtdFrame::ProcessBorders(nsTableFrame* aFrame,
+                                          nsDisplayListBuilder* aBuilder,
+                                          const nsDisplayListSet& aLists) {
+  aLists.BorderBackground()->AppendNewToTop<nsDisplaymtdBorder>(aBuilder, this);
+  return NS_OK;
+}
+
+LogicalMargin nsMathMLmtdFrame::GetBorderWidth(WritingMode aWM) const {
+  nsStyleBorder styleBorder = *StyleBorder();
+  ApplyBorderToStyle(this, styleBorder);
+  return LogicalMargin(aWM, styleBorder.GetComputedBorder());
+}
+
+nsMargin nsMathMLmtdFrame::GetBorderOverflow() {
+  nsStyleBorder styleBorder = *StyleBorder();
+  ApplyBorderToStyle(this, styleBorder);
+  nsMargin overflow = ComputeBorderOverflow(this, styleBorder);
+  return overflow;
+}
+
+// --------
+// implementation of nsMathMLmtdInnerFrame
+
+NS_QUERYFRAME_HEAD(nsMathMLmtdInnerFrame)
+  NS_QUERYFRAME_ENTRY(nsIMathMLFrame)
+NS_QUERYFRAME_TAIL_INHERITING(nsBlockFrame)
+
+nsContainerFrame* NS_NewMathMLmtdInnerFrame(PresShell* aPresShell,
+                                            ComputedStyle* aStyle) {
+  return new (aPresShell)
+      nsMathMLmtdInnerFrame(aStyle, aPresShell->GetPresContext());
+}
+
+NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmtdInnerFrame)
+
+nsMathMLmtdInnerFrame::nsMathMLmtdInnerFrame(ComputedStyle* aStyle,
+                                             nsPresContext* aPresContext)
+    : nsBlockFrame(aStyle, aPresContext, kClassID)
+      // Make a copy of the parent nsStyleText for later modification.
+      ,
+      mUniqueStyleText(MakeUnique<nsStyleText>(*StyleText())) {}
+
+void nsMathMLmtdInnerFrame::Reflow(nsPresContext* aPresContext,
+                                   ReflowOutput& aDesiredSize,
+                                   const ReflowInput& aReflowInput,
+                                   nsReflowStatus& aStatus) {
+  // Let the base class do the reflow
+  nsBlockFrame::Reflow(aPresContext, aDesiredSize, aReflowInput, aStatus);
+
+  // more about <maligngroup/> and <malignmark/> later
+  // ...
+}
+
+const nsStyleText* nsMathMLmtdInnerFrame::StyleTextForLineLayout() {
+  // Set the default alignment in case nothing was specified
+  auto alignment = uint8_t(StyleText()->mTextAlign);
+
+  nsTArray<int8_t>* alignmentList =
+      FindCellProperty(this, ColumnAlignProperty());
+
+  if (alignmentList) {
+    nsMathMLmtdFrame* cellFrame = (nsMathMLmtdFrame*)GetParent();
+    uint32_t columnIndex = cellFrame->ColIndex();
+
+    // If the column number is greater than the number of provided columalign
+    // values, we simply repeat the last value.
+    if (columnIndex < alignmentList->Length())
+      alignment = alignmentList->ElementAt(columnIndex);
+    else
+      alignment = alignmentList->ElementAt(alignmentList->Length() - 1);
+  }
+
+  mUniqueStyleText->mTextAlign = StyleTextAlign(alignment);
+  return mUniqueStyleText.get();
+}
+
+/* virtual */
+void nsMathMLmtdInnerFrame::DidSetComputedStyle(
+    ComputedStyle* aOldComputedStyle) {
+  nsBlockFrame::DidSetComputedStyle(aOldComputedStyle);
+  mUniqueStyleText = MakeUnique<nsStyleText>(*StyleText());
+}