Adding upstream version 124.0.1.upstream/124.0.1

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

6 files changed, 918 insertions, 0 deletions

diff --git a/dom/mathml/MathMLElement.cpp b/dom/mathml/MathMLElement.cpp
new file mode 100644
index 0000000000..b6d1ad7dec
--- /dev/null
+++ b/dom/mathml/MathMLElement.cpp
@@ -0,0 +1,711 @@
+/* -*- 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 "mozilla/dom/MathMLElement.h"
+
+#include "base/compiler_specific.h"
+#include "mozilla/dom/BindContext.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/EventListenerManager.h"
+#include "mozilla/FontPropertyTypes.h"
+#include "mozilla/StaticPrefs_mathml.h"
+#include "mozilla/TextUtils.h"
+#include "nsGkAtoms.h"
+#include "nsIContentInlines.h"
+#include "nsITableCellLayout.h"  // for MAX_COLSPAN / MAX_ROWSPAN
+#include "nsCSSValue.h"
+#include "nsStyleConsts.h"
+#include "mozilla/dom/Document.h"
+#include "nsPresContext.h"
+#include "mozAutoDocUpdate.h"
+#include "nsIScriptError.h"
+#include "nsContentUtils.h"
+#include "nsIURI.h"
+
+#include "mozilla/EventDispatcher.h"
+#include "mozilla/MappedDeclarationsBuilder.h"
+#include "mozilla/dom/MathMLElementBinding.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+//----------------------------------------------------------------------
+// nsISupports methods:
+
+NS_IMPL_ISUPPORTS_INHERITED(MathMLElement, MathMLElementBase, Link)
+
+static nsresult ReportLengthParseError(const nsString& aValue,
+                                       Document* aDocument) {
+  AutoTArray<nsString, 1> arg = {aValue};
+  return nsContentUtils::ReportToConsole(
+      nsIScriptError::errorFlag, "MathML"_ns, aDocument,
+      nsContentUtils::eMATHML_PROPERTIES, "LengthParsingError", arg);
+}
+
+static nsresult ReportParseErrorNoTag(const nsString& aValue, nsAtom* aAtom,
+                                      Document& aDocument) {
+  AutoTArray<nsString, 2> argv = {aValue, nsDependentAtomString(aAtom)};
+  return nsContentUtils::ReportToConsole(
+      nsIScriptError::errorFlag, "MathML"_ns, &aDocument,
+      nsContentUtils::eMATHML_PROPERTIES, "AttributeParsingErrorNoTag", argv);
+}
+
+MathMLElement::MathMLElement(
+    already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+    : MathMLElementBase(std::move(aNodeInfo)),
+      ALLOW_THIS_IN_INITIALIZER_LIST(Link(this)) {}
+
+MathMLElement::MathMLElement(
+    already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
+    : MathMLElementBase(std::move(aNodeInfo)),
+      ALLOW_THIS_IN_INITIALIZER_LIST(Link(this)) {}
+
+nsresult MathMLElement::BindToTree(BindContext& aContext, nsINode& aParent) {
+  nsresult rv = MathMLElementBase::BindToTree(aContext, aParent);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  Link::BindToTree(aContext);
+
+  // Set the bit in the document for telemetry.
+  if (Document* doc = aContext.GetComposedDoc()) {
+    doc->SetMathMLEnabled();
+  }
+
+  return rv;
+}
+
+void MathMLElement::UnbindFromTree(bool aNullParent) {
+  MathMLElementBase::UnbindFromTree(aNullParent);
+  // Without removing the link state we risk a dangling pointer in the
+  // mStyledLinks hashtable
+  Link::UnbindFromTree();
+}
+
+bool MathMLElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                                   const nsAString& aValue,
+                                   nsIPrincipal* aMaybeScriptedPrincipal,
+                                   nsAttrValue& aResult) {
+  MOZ_ASSERT(IsMathMLElement());
+
+  if (aNamespaceID == kNameSpaceID_None) {
+    if (aAttribute == nsGkAtoms::color || aAttribute == nsGkAtoms::mathcolor_ ||
+        aAttribute == nsGkAtoms::background ||
+        aAttribute == nsGkAtoms::mathbackground_) {
+      return aResult.ParseColor(aValue);
+    }
+    if (aAttribute == nsGkAtoms::tabindex) {
+      return aResult.ParseIntValue(aValue);
+    }
+    if (mNodeInfo->Equals(nsGkAtoms::mtd_)) {
+      if (aAttribute == nsGkAtoms::columnspan_) {
+        aResult.ParseClampedNonNegativeInt(aValue, 1, 1, MAX_COLSPAN);
+        return true;
+      }
+      if (aAttribute == nsGkAtoms::rowspan) {
+        aResult.ParseClampedNonNegativeInt(aValue, 1, 0, MAX_ROWSPAN);
+        return true;
+      }
+    }
+  }
+
+  return MathMLElementBase::ParseAttribute(aNamespaceID, aAttribute, aValue,
+                                           aMaybeScriptedPrincipal, aResult);
+}
+
+// https://mathml-refresh.github.io/mathml-core/#global-attributes
+static Element::MappedAttributeEntry sGlobalAttributes[] = {
+    {nsGkAtoms::dir},
+    {nsGkAtoms::mathbackground_},
+    {nsGkAtoms::mathcolor_},
+    {nsGkAtoms::mathsize_},
+    {nsGkAtoms::scriptlevel_},
+    {nsGkAtoms::displaystyle_},
+    {nullptr}};
+
+bool MathMLElement::IsAttributeMapped(const nsAtom* aAttribute) const {
+  MOZ_ASSERT(IsMathMLElement());
+
+  static const MappedAttributeEntry* const globalMap[] = {sGlobalAttributes};
+
+  return FindAttributeDependence(aAttribute, globalMap) ||
+         ((!StaticPrefs::mathml_legacy_mathvariant_attribute_disabled() ||
+           mNodeInfo->Equals(nsGkAtoms::mi_)) &&
+          aAttribute == nsGkAtoms::mathvariant_) ||
+         (mNodeInfo->Equals(nsGkAtoms::mtable_) &&
+          aAttribute == nsGkAtoms::width);
+}
+
+nsMapRuleToAttributesFunc MathMLElement::GetAttributeMappingFunction() const {
+  if (mNodeInfo->Equals(nsGkAtoms::mtable_)) {
+    return &MapMTableAttributesInto;
+  }
+  if (StaticPrefs::mathml_legacy_mathvariant_attribute_disabled() &&
+      mNodeInfo->Equals(nsGkAtoms::mi_)) {
+    return &MapMiAttributesInto;
+  }
+  return &MapGlobalMathMLAttributesInto;
+}
+
+/* static */
+bool MathMLElement::ParseNamedSpaceValue(const nsString& aString,
+                                         nsCSSValue& aCSSValue, uint32_t aFlags,
+                                         const Document& aDocument) {
+  if (StaticPrefs::mathml_mathspace_names_disabled()) {
+    return false;
+  }
+  int32_t i = 0;
+  // See if it is one of the 'namedspace' (ranging -7/18em, -6/18, ... 7/18em)
+  if (aString.EqualsLiteral("veryverythinmathspace")) {
+    i = 1;
+  } else if (aString.EqualsLiteral("verythinmathspace")) {
+    i = 2;
+  } else if (aString.EqualsLiteral("thinmathspace")) {
+    i = 3;
+  } else if (aString.EqualsLiteral("mediummathspace")) {
+    i = 4;
+  } else if (aString.EqualsLiteral("thickmathspace")) {
+    i = 5;
+  } else if (aString.EqualsLiteral("verythickmathspace")) {
+    i = 6;
+  } else if (aString.EqualsLiteral("veryverythickmathspace")) {
+    i = 7;
+  } else if (aFlags & PARSE_ALLOW_NEGATIVE) {
+    if (aString.EqualsLiteral("negativeveryverythinmathspace")) {
+      i = -1;
+    } else if (aString.EqualsLiteral("negativeverythinmathspace")) {
+      i = -2;
+    } else if (aString.EqualsLiteral("negativethinmathspace")) {
+      i = -3;
+    } else if (aString.EqualsLiteral("negativemediummathspace")) {
+      i = -4;
+    } else if (aString.EqualsLiteral("negativethickmathspace")) {
+      i = -5;
+    } else if (aString.EqualsLiteral("negativeverythickmathspace")) {
+      i = -6;
+    } else if (aString.EqualsLiteral("negativeveryverythickmathspace")) {
+      i = -7;
+    }
+  }
+  if (0 != i) {
+    AutoTArray<nsString, 1> params;
+    params.AppendElement(aString);
+    aDocument.WarnOnceAbout(
+        dom::DeprecatedOperations::eMathML_DeprecatedMathSpaceValue2, false,
+        params);
+    aCSSValue.SetFloatValue(float(i) / float(18), eCSSUnit_EM);
+    return true;
+  }
+
+  return false;
+}
+
+// The REC says:
+//
+// "Most presentation elements have attributes that accept values representing
+// lengths to be used for size, spacing or similar properties. The syntax of a
+// length is specified as
+//
+// number | number unit | namedspace
+//
+// There should be no space between the number and the unit of a length."
+//
+// "A trailing '%' represents a percent of the default value. The default
+// value, or how it is obtained, is listed in the table of attributes for each
+// element. [...] A number without a unit is intepreted as a multiple of the
+// default value."
+//
+// "The possible units in MathML are:
+//
+// Unit Description
+// em   an em (font-relative unit traditionally used for horizontal lengths)
+// ex   an ex (font-relative unit traditionally used for vertical lengths)
+// px   pixels, or size of a pixel in the current display
+// in   inches (1 inch = 2.54 centimeters)
+// cm   centimeters
+// mm   millimeters
+// pt   points (1 point = 1/72 inch)
+// pc   picas (1 pica = 12 points)
+// %    percentage of default value"
+//
+// The numbers are defined that way:
+// - unsigned-number: "a string of decimal digits with up to one decimal point
+//   (U+002E), representing a non-negative terminating decimal number (a type of
+//   rational number)"
+// - number: "an optional prefix of '-' (U+002D), followed by an unsigned
+//   number, representing a terminating decimal number (a type of rational
+//   number)"
+//
+/* static */
+// XXXfredw: Deprecate legacy MathML syntax and use the CSS parser instead.
+// See https://github.com/mathml-refresh/mathml/issues/63
+bool MathMLElement::ParseNumericValue(const nsString& aString,
+                                      nsCSSValue& aCSSValue, uint32_t aFlags,
+                                      Document* aDocument) {
+  nsAutoString str(aString);
+  str.CompressWhitespace();  // aString is const in this code...
+
+  int32_t stringLength = str.Length();
+  if (!stringLength) {
+    if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+      ReportLengthParseError(aString, aDocument);
+    }
+    return false;
+  }
+
+  if (aDocument && ParseNamedSpaceValue(str, aCSSValue, aFlags, *aDocument)) {
+    return true;
+  }
+
+  nsAutoString number, unit;
+
+  // see if the negative sign is there
+  int32_t i = 0;
+  char16_t c = str[0];
+  if (c == '-') {
+    number.Append(c);
+    i++;
+  }
+
+  // Gather up characters that make up the number
+  bool gotDot = false;
+  for (; i < stringLength; i++) {
+    c = str[i];
+    if (gotDot && c == '.') {
+      if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+        ReportLengthParseError(aString, aDocument);
+      }
+      return false;  // two dots encountered
+    } else if (c == '.')
+      gotDot = true;
+    else if (!IsAsciiDigit(c)) {
+      str.Right(unit, stringLength - i);
+      // some authors leave blanks before the unit, but that shouldn't
+      // be allowed, so don't CompressWhitespace on 'unit'.
+      break;
+    }
+    number.Append(c);
+  }
+  if (gotDot && str[i - 1] == '.') {
+    if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+      ReportLengthParseError(aString, aDocument);
+    }
+    return false;  // Number ending with a dot.
+  }
+
+  // Convert number to floating point
+  nsresult errorCode;
+  float floatValue = number.ToFloat(&errorCode);
+  if (NS_FAILED(errorCode)) {
+    if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+      ReportLengthParseError(aString, aDocument);
+    }
+    return false;
+  }
+  if (floatValue < 0 && !(aFlags & PARSE_ALLOW_NEGATIVE)) {
+    if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+      ReportLengthParseError(aString, aDocument);
+    }
+    return false;
+  }
+
+  nsCSSUnit cssUnit;
+  if (unit.IsEmpty()) {
+    // We are supposed to have a unit, but there isn't one.
+    // If the value is 0 we can just call it "pixels" otherwise
+    // this is illegal.
+    if (floatValue != 0.0) {
+      if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+        ReportLengthParseError(aString, aDocument);
+      }
+      return false;
+    }
+    cssUnit = eCSSUnit_Pixel;
+  } else if (unit.EqualsLiteral("%")) {
+    aCSSValue.SetPercentValue(floatValue / 100.0f);
+    return true;
+  } else if (unit.LowerCaseEqualsLiteral("em"))
+    cssUnit = eCSSUnit_EM;
+  else if (unit.LowerCaseEqualsLiteral("ex"))
+    cssUnit = eCSSUnit_XHeight;
+  else if (unit.LowerCaseEqualsLiteral("px"))
+    cssUnit = eCSSUnit_Pixel;
+  else if (unit.LowerCaseEqualsLiteral("in"))
+    cssUnit = eCSSUnit_Inch;
+  else if (unit.LowerCaseEqualsLiteral("cm"))
+    cssUnit = eCSSUnit_Centimeter;
+  else if (unit.LowerCaseEqualsLiteral("mm"))
+    cssUnit = eCSSUnit_Millimeter;
+  else if (unit.LowerCaseEqualsLiteral("pt"))
+    cssUnit = eCSSUnit_Point;
+  else if (unit.LowerCaseEqualsLiteral("pc"))
+    cssUnit = eCSSUnit_Pica;
+  else if (unit.LowerCaseEqualsLiteral("q"))
+    cssUnit = eCSSUnit_Quarter;
+  else {  // unexpected unit
+    if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
+      ReportLengthParseError(aString, aDocument);
+    }
+    return false;
+  }
+
+  aCSSValue.SetFloatValue(floatValue, cssUnit);
+  return true;
+}
+
+void MathMLElement::MapMTableAttributesInto(
+    MappedDeclarationsBuilder& aBuilder) {
+  // width
+  //
+  // "Specifies the desired width of the entire table and is intended for
+  // visual user agents. When the value is a percentage value, the value is
+  // relative to the horizontal space a MathML renderer has available for the
+  // math element. When the value is "auto", the MathML renderer should
+  // calculate the table width from its contents using whatever layout
+  // algorithm it chooses. "
+  //
+  // values: "auto" | length
+  // default: auto
+  //
+  if (!aBuilder.PropertyIsSet(eCSSProperty_width)) {
+    const nsAttrValue* value = aBuilder.GetAttr(nsGkAtoms::width);
+    nsCSSValue width;
+    // This does not handle auto and unitless values
+    if (value && value->Type() == nsAttrValue::eString) {
+      ParseNumericValue(value->GetStringValue(), width, 0,
+                        &aBuilder.Document());
+      if (width.GetUnit() == eCSSUnit_Percent) {
+        aBuilder.SetPercentValue(eCSSProperty_width, width.GetPercentValue());
+      } else if (width.GetUnit() != eCSSUnit_Null) {
+        aBuilder.SetLengthValue(eCSSProperty_width, width);
+      }
+    }
+  }
+  MapGlobalMathMLAttributesInto(aBuilder);
+}
+
+void MathMLElement::MapMiAttributesInto(MappedDeclarationsBuilder& aBuilder) {
+  // mathvariant
+  // https://w3c.github.io/mathml-core/#dfn-mathvariant
+  if (!aBuilder.PropertyIsSet(eCSSProperty_text_transform)) {
+    const nsAttrValue* value = aBuilder.GetAttr(nsGkAtoms::mathvariant_);
+    if (value && value->Type() == nsAttrValue::eString) {
+      auto str = value->GetStringValue();
+      str.CompressWhitespace();
+      if (value->GetStringValue().LowerCaseEqualsASCII("normal")) {
+        aBuilder.SetKeywordValue(eCSSProperty_text_transform,
+                                 StyleTextTransformCase::None);
+      }
+    }
+  }
+  MapGlobalMathMLAttributesInto(aBuilder);
+}
+
+void MathMLElement::MapGlobalMathMLAttributesInto(
+    MappedDeclarationsBuilder& aBuilder) {
+  // scriptlevel
+  // https://w3c.github.io/mathml-core/#dfn-scriptlevel
+  const nsAttrValue* value = aBuilder.GetAttr(nsGkAtoms::scriptlevel_);
+  if (value && value->Type() == nsAttrValue::eString &&
+      !aBuilder.PropertyIsSet(eCSSProperty_math_depth)) {
+    auto str = value->GetStringValue();
+    // FIXME: Should we remove whitespace trimming?
+    // See https://github.com/w3c/mathml/issues/122
+    str.CompressWhitespace();
+    if (str.Length() > 0) {
+      nsresult errorCode;
+      int32_t intValue = str.ToInteger(&errorCode);
+      bool reportParseError = true;
+      if (NS_SUCCEEDED(errorCode)) {
+        char16_t ch = str.CharAt(0);
+        bool isRelativeScriptLevel = (ch == '+' || ch == '-');
+        // ToInteger is not very strict, check this is really <unsigned>.
+        reportParseError = false;
+        for (uint32_t i = isRelativeScriptLevel ? 1 : 0; i < str.Length();
+             i++) {
+          if (!IsAsciiDigit(str.CharAt(i))) {
+            reportParseError = true;
+            break;
+          }
+        }
+        if (!reportParseError) {
+          aBuilder.SetMathDepthValue(intValue, isRelativeScriptLevel);
+        }
+      }
+      if (reportParseError) {
+        ReportParseErrorNoTag(str, nsGkAtoms::scriptlevel_,
+                              aBuilder.Document());
+      }
+    }
+  }
+
+  // mathsize
+  // https://w3c.github.io/mathml-core/#dfn-mathsize
+  value = aBuilder.GetAttr(nsGkAtoms::mathsize_);
+  if (value && value->Type() == nsAttrValue::eString &&
+      !aBuilder.PropertyIsSet(eCSSProperty_font_size)) {
+    auto str = value->GetStringValue();
+    nsCSSValue fontSize;
+    ParseNumericValue(str, fontSize, 0, nullptr);
+    if (fontSize.GetUnit() == eCSSUnit_Percent) {
+      aBuilder.SetPercentValue(eCSSProperty_font_size,
+                               fontSize.GetPercentValue());
+    } else if (fontSize.GetUnit() != eCSSUnit_Null) {
+      aBuilder.SetLengthValue(eCSSProperty_font_size, fontSize);
+    }
+  }
+
+  if (!StaticPrefs::mathml_legacy_mathvariant_attribute_disabled()) {
+    // mathvariant
+    //
+    // "Specifies the logical class of the token. Note that this class is more
+    // than styling, it typically conveys semantic intent;"
+    //
+    // values: "normal" | "bold" | "italic" | "bold-italic" | "double-struck" |
+    // "bold-fraktur" | "script" | "bold-script" | "fraktur" | "sans-serif" |
+    // "bold-sans-serif" | "sans-serif-italic" | "sans-serif-bold-italic" |
+    // "monospace" | "initial" | "tailed" | "looped" | "stretched"
+    // default: normal (except on <mi>)
+    //
+    value = aBuilder.GetAttr(nsGkAtoms::mathvariant_);
+    if (value && value->Type() == nsAttrValue::eString &&
+        !aBuilder.PropertyIsSet(eCSSProperty__moz_math_variant)) {
+      auto str = value->GetStringValue();
+      str.CompressWhitespace();
+      static const char sizes[19][23] = {"normal",
+                                         "bold",
+                                         "italic",
+                                         "bold-italic",
+                                         "script",
+                                         "bold-script",
+                                         "fraktur",
+                                         "double-struck",
+                                         "bold-fraktur",
+                                         "sans-serif",
+                                         "bold-sans-serif",
+                                         "sans-serif-italic",
+                                         "sans-serif-bold-italic",
+                                         "monospace",
+                                         "initial",
+                                         "tailed",
+                                         "looped",
+                                         "stretched"};
+      static const StyleMathVariant values[MOZ_ARRAY_LENGTH(sizes)] = {
+          StyleMathVariant::Normal,
+          StyleMathVariant::Bold,
+          StyleMathVariant::Italic,
+          StyleMathVariant::BoldItalic,
+          StyleMathVariant::Script,
+          StyleMathVariant::BoldScript,
+          StyleMathVariant::Fraktur,
+          StyleMathVariant::DoubleStruck,
+          StyleMathVariant::BoldFraktur,
+          StyleMathVariant::SansSerif,
+          StyleMathVariant::BoldSansSerif,
+          StyleMathVariant::SansSerifItalic,
+          StyleMathVariant::SansSerifBoldItalic,
+          StyleMathVariant::Monospace,
+          StyleMathVariant::Initial,
+          StyleMathVariant::Tailed,
+          StyleMathVariant::Looped,
+          StyleMathVariant::Stretched};
+      for (uint32_t i = 0; i < ArrayLength(sizes); ++i) {
+        if (str.LowerCaseEqualsASCII(sizes[i])) {
+          if (values[i] != StyleMathVariant::Normal) {
+            // Warn about deprecated mathvariant attribute values. Strictly
+            // speaking, we should also warn about mathvariant="normal" if the
+            // element is not an <mi>. However this would require exposing the
+            // tag name via aBuilder. Moreover, this use case is actually to
+            // revert the effect of a non-normal mathvariant value on an
+            // ancestor element, which should consequently have already
+            // triggered a warning.
+            AutoTArray<nsString, 1> params;
+            params.AppendElement(str);
+            aBuilder.Document().WarnOnceAbout(
+                dom::DeprecatedOperations::eMathML_DeprecatedMathVariant, false,
+                params);
+          }
+          aBuilder.SetKeywordValue(eCSSProperty__moz_math_variant, values[i]);
+          break;
+        }
+      }
+    }
+  }
+
+  // mathbackground
+  // https://w3c.github.io/mathml-core/#dfn-mathbackground
+  value = aBuilder.GetAttr(nsGkAtoms::mathbackground_);
+  if (value) {
+    nscolor color;
+    if (value->GetColorValue(color)) {
+      aBuilder.SetColorValueIfUnset(eCSSProperty_background_color, color);
+    }
+  }
+
+  // mathcolor
+  // https://w3c.github.io/mathml-core/#dfn-mathcolor
+  value = aBuilder.GetAttr(nsGkAtoms::mathcolor_);
+  nscolor color;
+  if (value && value->GetColorValue(color)) {
+    aBuilder.SetColorValueIfUnset(eCSSProperty_color, color);
+  }
+
+  // dir
+  // https://w3c.github.io/mathml-core/#dfn-dir
+  value = aBuilder.GetAttr(nsGkAtoms::dir);
+  if (value && value->Type() == nsAttrValue::eString &&
+      !aBuilder.PropertyIsSet(eCSSProperty_direction)) {
+    auto str = value->GetStringValue();
+    static const char dirs[][4] = {"ltr", "rtl"};
+    static const StyleDirection dirValues[MOZ_ARRAY_LENGTH(dirs)] = {
+        StyleDirection::Ltr, StyleDirection::Rtl};
+    for (uint32_t i = 0; i < ArrayLength(dirs); ++i) {
+      if (str.LowerCaseEqualsASCII(dirs[i])) {
+        aBuilder.SetKeywordValue(eCSSProperty_direction, dirValues[i]);
+        break;
+      }
+    }
+  }
+
+  // displaystyle
+  // https://mathml-refresh.github.io/mathml-core/#dfn-displaystyle
+  value = aBuilder.GetAttr(nsGkAtoms::displaystyle_);
+  if (value && value->Type() == nsAttrValue::eString &&
+      !aBuilder.PropertyIsSet(eCSSProperty_math_style)) {
+    auto str = value->GetStringValue();
+    static const char displaystyles[][6] = {"false", "true"};
+    static const StyleMathStyle mathStyle[MOZ_ARRAY_LENGTH(displaystyles)] = {
+        StyleMathStyle::Compact, StyleMathStyle::Normal};
+    for (uint32_t i = 0; i < ArrayLength(displaystyles); ++i) {
+      if (str.LowerCaseEqualsASCII(displaystyles[i])) {
+        aBuilder.SetKeywordValue(eCSSProperty_math_style, mathStyle[i]);
+        break;
+      }
+    }
+  }
+}
+
+void MathMLElement::GetEventTargetParent(EventChainPreVisitor& aVisitor) {
+  Element::GetEventTargetParent(aVisitor);
+
+  GetEventTargetParentForLinks(aVisitor);
+}
+
+nsresult MathMLElement::PostHandleEvent(EventChainPostVisitor& aVisitor) {
+  return PostHandleEventForLinks(aVisitor);
+}
+
+NS_IMPL_ELEMENT_CLONE(MathMLElement)
+
+void MathMLElement::SetIncrementScriptLevel(bool aIncrementScriptLevel,
+                                            bool aNotify) {
+  NS_ASSERTION(aNotify, "We always notify!");
+  if (aIncrementScriptLevel) {
+    AddStates(ElementState::INCREMENT_SCRIPT_LEVEL);
+  } else {
+    RemoveStates(ElementState::INCREMENT_SCRIPT_LEVEL);
+  }
+}
+
+int32_t MathMLElement::TabIndexDefault() { return IsLink() ? 0 : -1; }
+
+// XXX Bug 1586011: Share logic with other element classes.
+Focusable MathMLElement::IsFocusableWithoutStyle(bool aWithMouse) {
+  if (!IsInComposedDoc() || IsInDesignMode()) {
+    // In designMode documents we only allow focusing the document.
+    return {};
+  }
+
+  int32_t tabIndex = TabIndex();
+  if (!IsLink()) {
+    // If a tabindex is specified at all we're focusable
+    if (GetTabIndexAttrValue().isSome()) {
+      return {true, tabIndex};
+    }
+    return {};
+  }
+
+  if (!OwnerDoc()->LinkHandlingEnabled()) {
+    return {};
+  }
+
+  // Links that are in an editable region should never be focusable, even if
+  // they are in a contenteditable="false" region.
+  if (nsContentUtils::IsNodeInEditableRegion(this)) {
+    return {};
+  }
+
+  if ((sTabFocusModel & eTabFocus_linksMask) == 0) {
+    tabIndex = -1;
+  }
+
+  return {true, tabIndex};
+}
+
+already_AddRefed<nsIURI> MathMLElement::GetHrefURI() const {
+  // MathML href
+  // The REC says: "When user agents encounter MathML elements with both href
+  // and xlink:href attributes, the href attribute should take precedence."
+  const nsAttrValue* href = mAttrs.GetAttr(nsGkAtoms::href, kNameSpaceID_None);
+  if (!href) {
+    return nullptr;
+  }
+  // Get absolute URI
+  nsAutoString hrefStr;
+  href->ToString(hrefStr);
+  nsCOMPtr<nsIURI> hrefURI;
+  nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(hrefURI), hrefStr,
+                                            OwnerDoc(), GetBaseURI());
+  return hrefURI.forget();
+}
+
+bool MathMLElement::IsEventAttributeNameInternal(nsAtom* aName) {
+  // The intent is to align MathML event attributes on HTML5, so the flag
+  // EventNameType_HTML is used here.
+  return nsContentUtils::IsEventAttributeName(aName, EventNameType_HTML);
+}
+
+void MathMLElement::BeforeSetAttr(int32_t aNamespaceID, nsAtom* aName,
+                                  const nsAttrValue* aValue, bool aNotify) {
+  if (aNamespaceID == kNameSpaceID_None) {
+    if (!aValue && IsEventAttributeName(aName)) {
+      if (EventListenerManager* manager = GetExistingListenerManager()) {
+        manager->RemoveEventHandler(GetEventNameForAttr(aName));
+      }
+    }
+  }
+
+  return MathMLElementBase::BeforeSetAttr(aNamespaceID, aName, aValue, aNotify);
+}
+
+void MathMLElement::AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
+                                 const nsAttrValue* aValue,
+                                 const nsAttrValue* aOldValue,
+                                 nsIPrincipal* aSubjectPrincipal,
+                                 bool aNotify) {
+  // It is important that this be done after the attribute is set/unset.
+  // We will need the updated attribute value because notifying the document
+  // that content states have changed will call IntrinsicState, which will try
+  // to get updated information about the visitedness from Link.
+  if (aName == nsGkAtoms::href && aNameSpaceID == kNameSpaceID_None) {
+    Link::ResetLinkState(aNotify, aValue || Link::ElementHasHref());
+  }
+
+  if (aNameSpaceID == kNameSpaceID_None) {
+    if (IsEventAttributeName(aName) && aValue) {
+      MOZ_ASSERT(aValue->Type() == nsAttrValue::eString,
+                 "Expected string value for script body");
+      SetEventHandler(GetEventNameForAttr(aName), aValue->GetStringValue());
+    }
+  }
+
+  return MathMLElementBase::AfterSetAttr(aNameSpaceID, aName, aValue, aOldValue,
+                                         aSubjectPrincipal, aNotify);
+}
+
+JSObject* MathMLElement::WrapNode(JSContext* aCx,
+                                  JS::Handle<JSObject*> aGivenProto) {
+  return MathMLElement_Binding::Wrap(aCx, this, aGivenProto);
+}
diff --git a/dom/mathml/MathMLElement.h b/dom/mathml/MathMLElement.h
new file mode 100644
index 0000000000..46198d877d
--- /dev/null
+++ b/dom/mathml/MathMLElement.h
@@ -0,0 +1,111 @@
+/* -*- 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/. */
+
+#ifndef mozilla_dom_MathMLElement_h_
+#define mozilla_dom_MathMLElement_h_
+
+#include "mozilla/Attributes.h"
+#include "nsStyledElement.h"
+#include "Link.h"
+
+class nsCSSValue;
+
+namespace mozilla {
+class EventChainPostVisitor;
+class EventChainPreVisitor;
+namespace dom {
+
+using MathMLElementBase = nsStyledElement;
+
+/*
+ * The base class for MathML elements.
+ */
+class MathMLElement final : public MathMLElementBase, public Link {
+ public:
+  explicit MathMLElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit MathMLElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
+
+  // Implementation of nsISupports is inherited from MathMLElementBase
+  NS_DECL_ISUPPORTS_INHERITED
+
+  NS_IMPL_FROMNODE(MathMLElement, kNameSpaceID_MathML)
+
+  nsresult BindToTree(BindContext&, nsINode& aParent) override;
+  void UnbindFromTree(bool aNullParent = true) override;
+
+  bool ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
+                      const nsAString& aValue,
+                      nsIPrincipal* aMaybeScriptedPrincipal,
+                      nsAttrValue& aResult) override;
+
+  NS_IMETHOD_(bool) IsAttributeMapped(const nsAtom* aAttribute) const override;
+  nsMapRuleToAttributesFunc GetAttributeMappingFunction() const override;
+
+  enum {
+    PARSE_ALLOW_NEGATIVE = 0x02,
+    PARSE_SUPPRESS_WARNINGS = 0x04,
+  };
+  static bool ParseNamedSpaceValue(const nsString& aString,
+                                   nsCSSValue& aCSSValue, uint32_t aFlags,
+                                   const Document& aDocument);
+
+  static bool ParseNumericValue(const nsString& aString, nsCSSValue& aCSSValue,
+                                uint32_t aFlags, Document* aDocument);
+
+  static void MapGlobalMathMLAttributesInto(
+      mozilla::MappedDeclarationsBuilder&);
+  static void MapMiAttributesInto(mozilla::MappedDeclarationsBuilder&);
+  static void MapMTableAttributesInto(mozilla::MappedDeclarationsBuilder&);
+
+  void GetEventTargetParent(mozilla::EventChainPreVisitor& aVisitor) override;
+  MOZ_CAN_RUN_SCRIPT
+  nsresult PostHandleEvent(mozilla::EventChainPostVisitor& aVisitor) override;
+  nsresult Clone(mozilla::dom::NodeInfo*, nsINode** aResult) const override;
+
+  // Set during reflow as necessary. Does a style change notification,
+  // aNotify must be true.
+  void SetIncrementScriptLevel(bool aIncrementScriptLevel, bool aNotify);
+  bool GetIncrementScriptLevel() const {
+    return Element::State().HasState(ElementState::INCREMENT_SCRIPT_LEVEL);
+  }
+
+  int32_t TabIndexDefault() final;
+
+  Focusable IsFocusableWithoutStyle(bool aWithMouse) override;
+  already_AddRefed<nsIURI> GetHrefURI() const override;
+
+  void NodeInfoChanged(Document* aOldDoc) override {
+    ClearHasPendingLinkUpdate();
+    MathMLElementBase::NodeInfoChanged(aOldDoc);
+  }
+
+  bool IsEventAttributeNameInternal(nsAtom* aName) final;
+
+  bool Autofocus() const { return GetBoolAttr(nsGkAtoms::autofocus); }
+  void SetAutofocus(bool aAutofocus, ErrorResult& aRv) {
+    if (aAutofocus) {
+      SetAttr(nsGkAtoms::autofocus, u""_ns, aRv);
+    } else {
+      UnsetAttr(nsGkAtoms::autofocus, aRv);
+    }
+  }
+
+ protected:
+  virtual ~MathMLElement() = default;
+
+  JSObject* WrapNode(JSContext*, JS::Handle<JSObject*> aGivenProto) override;
+
+  void BeforeSetAttr(int32_t aNamespaceID, nsAtom* aName,
+                     const nsAttrValue* aValue, bool aNotify) final;
+  void AfterSetAttr(int32_t aNameSpaceID, nsAtom* aName,
+                    const nsAttrValue* aValue, const nsAttrValue* aOldValue,
+                    nsIPrincipal* aSubjectPrincipal, bool aNotify) override;
+};
+
+}  // namespace dom
+}  // namespace mozilla
+
+#endif  // mozilla_dom_MathMLElement_h_
diff --git a/dom/mathml/MathMLElementFactory.cpp b/dom/mathml/MathMLElementFactory.cpp
new file mode 100644
index 0000000000..ee8df090c9
--- /dev/null
+++ b/dom/mathml/MathMLElementFactory.cpp
@@ -0,0 +1,20 @@
+/* -*- 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 "nsContentCreatorFunctions.h"
+#include "nsGkAtoms.h"
+#include "mozilla/dom/MathMLElement.h"
+
+using namespace mozilla::dom;
+
+// MathML Element Factory (declared in nsContentCreatorFunctions.h)
+nsresult NS_NewMathMLElement(
+    Element** aResult, already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo) {
+  RefPtr<mozilla::dom::NodeInfo> nodeInfo(aNodeInfo);
+  auto* nim = nodeInfo->NodeInfoManager();
+  NS_ADDREF(*aResult = new (nim) MathMLElement(nodeInfo.forget()));
+  return NS_OK;
+}
diff --git a/dom/mathml/moz.build b/dom/mathml/moz.build
new file mode 100644
index 0000000000..e8b9fd61bb
--- /dev/null
+++ b/dom/mathml/moz.build
@@ -0,0 +1,26 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# 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/.
+
+with Files("**"):
+    BUG_COMPONENT = ("Core", "MathML")
+
+EXPORTS.mozilla.dom += [
+    "MathMLElement.h",
+]
+
+UNIFIED_SOURCES += [
+    "MathMLElement.cpp",
+    "MathMLElementFactory.cpp",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul"
+LOCAL_INCLUDES += [
+    "/dom/base",
+]
+
+MOCHITEST_MANIFESTS += ["tests/mochitest/mochitest.toml"]
diff --git a/dom/mathml/tests/mochitest/mochitest.toml b/dom/mathml/tests/mochitest/mochitest.toml
new file mode 100644
index 0000000000..3da0a28b92
--- /dev/null
+++ b/dom/mathml/tests/mochitest/mochitest.toml
@@ -0,0 +1,3 @@
+[DEFAULT]
+
+["test_math_tabindex_focus.html"]
diff --git a/dom/mathml/tests/mochitest/test_math_tabindex_focus.html b/dom/mathml/tests/mochitest/test_math_tabindex_focus.html
new file mode 100644
index 0000000000..fe03c13358
--- /dev/null
+++ b/dom/mathml/tests/mochitest/test_math_tabindex_focus.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1128054
+-->
+<head>
+  <title>Test for Bug 1128054</title>
+  <script src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1128054">Mozilla Bug 1128054</a>
+<p id="display"></p>
+<!-- Test default focusability -->
+<math></math>
+<math href="#" data-focusable=true></math>
+<!-- Test tabindex=0 focusability -->
+<math tabindex="0" data-focusable=true></math>
+<!-- Test tabindex=-1 focusability -->
+<math tabindex="-1" data-focusable=true></math>
+<!-- Test tabindex=invalid focusability -->
+<math tabindex="invalid"></math>
+<math href="#" tabindex="invalid" data-focusable=true></math>
+<!-- Tests code -->
+<script class="testbody" type="text/javascript">
+
+/** Test for Bug 1128054 **/
+
+add_task(function test_math_tabindex_focus() {
+  for (let element of document.querySelectorAll("math")) {
+    let focusable = element.dataset && element.dataset.focusable;
+    let desc = "<math";
+    for (let attr of ["href", "tabindex"]) {
+      if (element.hasAttribute(attr)) {
+        desc += ` ${attr}=${element.getAttribute(attr)}`;
+      }
+    }
+    desc += ">";
+    element.focus();
+    focusable ? is(document.activeElement, element, desc + " should focusable")
+              : isnot(document.activeElement, element, desc + " should not focusable");
+  }
+});
+
+</script>
+</body>
+</html>