/* -*- 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 "nsTreeSanitizer.h"

#include "mozilla/ArrayUtils.h"
#include "mozilla/CSSStyleSheet.h"
#include "mozilla/css/Declaration.h"
#include "mozilla/css/StyleRule.h"
#include "mozilla/css/Rule.h"
#include "nsCSSParser.h"
#include "nsCSSProperty.h"
#include "nsUnicharInputStream.h"
#include "nsIDOMCSSRule.h"
#include "nsAttrName.h"
#include "nsIScriptSecurityManager.h"
#include "nsNetUtil.h"
#include "nsComponentManagerUtils.h"
#include "nsNullPrincipal.h"
#include "nsContentUtils.h"
#include "nsIParserUtils.h"
#include "nsIDocument.h"
#include "nsQueryObject.h"

using namespace mozilla;

//
// Thanks to Mark Pilgrim and Sam Ruby for the initial whitelist
//
nsIAtom** const kElementsHTML[] = {
  &nsGkAtoms::a,
  &nsGkAtoms::abbr,
  &nsGkAtoms::acronym,
  &nsGkAtoms::address,
  &nsGkAtoms::area,
  &nsGkAtoms::article,
  &nsGkAtoms::aside,
  &nsGkAtoms::audio,
  &nsGkAtoms::b,
  &nsGkAtoms::bdi,
  &nsGkAtoms::bdo,
  &nsGkAtoms::big,
  &nsGkAtoms::blockquote,
  // body checked specially
  &nsGkAtoms::br,
  &nsGkAtoms::button,
  &nsGkAtoms::canvas,
  &nsGkAtoms::caption,
  &nsGkAtoms::center,
  &nsGkAtoms::cite,
  &nsGkAtoms::code,
  &nsGkAtoms::col,
  &nsGkAtoms::colgroup,
  &nsGkAtoms::datalist,
  &nsGkAtoms::dd,
  &nsGkAtoms::del,
  &nsGkAtoms::details,
  &nsGkAtoms::dfn,
  &nsGkAtoms::dir,
  &nsGkAtoms::div,
  &nsGkAtoms::dl,
  &nsGkAtoms::dt,
  &nsGkAtoms::em,
  &nsGkAtoms::fieldset,
  &nsGkAtoms::figcaption,
  &nsGkAtoms::figure,
  &nsGkAtoms::font,
  &nsGkAtoms::footer,
  &nsGkAtoms::form,
  &nsGkAtoms::h1,
  &nsGkAtoms::h2,
  &nsGkAtoms::h3,
  &nsGkAtoms::h4,
  &nsGkAtoms::h5,
  &nsGkAtoms::h6,
  // head checked specially
  &nsGkAtoms::header,
  &nsGkAtoms::hgroup,
  &nsGkAtoms::hr,
  // html checked specially
  &nsGkAtoms::i,
  &nsGkAtoms::img,
  &nsGkAtoms::input,
  &nsGkAtoms::ins,
  &nsGkAtoms::kbd,
  &nsGkAtoms::label,
  &nsGkAtoms::legend,
  &nsGkAtoms::li,
  &nsGkAtoms::link,
  &nsGkAtoms::listing,
  &nsGkAtoms::map,
  &nsGkAtoms::mark,
  &nsGkAtoms::menu,
  &nsGkAtoms::meta,
  &nsGkAtoms::meter,
  &nsGkAtoms::nav,
  &nsGkAtoms::nobr,
  &nsGkAtoms::noscript,
  &nsGkAtoms::ol,
  &nsGkAtoms::optgroup,
  &nsGkAtoms::option,
  &nsGkAtoms::output,
  &nsGkAtoms::p,
  &nsGkAtoms::pre,
  &nsGkAtoms::progress,
  &nsGkAtoms::q,
  &nsGkAtoms::rb,
  &nsGkAtoms::rp,
  &nsGkAtoms::rt,
  &nsGkAtoms::rtc,
  &nsGkAtoms::ruby,
  &nsGkAtoms::s,
  &nsGkAtoms::samp,
  &nsGkAtoms::section,
  &nsGkAtoms::select,
  &nsGkAtoms::small,
  &nsGkAtoms::source,
  &nsGkAtoms::span,
  &nsGkAtoms::strike,
  &nsGkAtoms::strong,
  &nsGkAtoms::sub,
  &nsGkAtoms::summary,
  &nsGkAtoms::sup,
  // style checked specially
  &nsGkAtoms::table,
  &nsGkAtoms::tbody,
  &nsGkAtoms::td,
  &nsGkAtoms::textarea,
  &nsGkAtoms::tfoot,
  &nsGkAtoms::th,
  &nsGkAtoms::thead,
  &nsGkAtoms::time,
  // title checked specially
  &nsGkAtoms::tr,
  &nsGkAtoms::track,
  &nsGkAtoms::tt,
  &nsGkAtoms::u,
  &nsGkAtoms::ul,
  &nsGkAtoms::var,
  &nsGkAtoms::video,
  &nsGkAtoms::wbr,
  nullptr
};

nsIAtom** const kAttributesHTML[] = {
  &nsGkAtoms::abbr,
  &nsGkAtoms::accept,
  &nsGkAtoms::acceptcharset,
  &nsGkAtoms::accesskey,
  &nsGkAtoms::action,
  &nsGkAtoms::alt,
  &nsGkAtoms::autocomplete,
  &nsGkAtoms::autofocus,
  &nsGkAtoms::autoplay,
  &nsGkAtoms::axis,
  &nsGkAtoms::_char,
  &nsGkAtoms::charoff,
  &nsGkAtoms::charset,
  &nsGkAtoms::checked,
  &nsGkAtoms::cite,
  &nsGkAtoms::_class,
  &nsGkAtoms::cols,
  &nsGkAtoms::colspan,
  &nsGkAtoms::content,
  &nsGkAtoms::contenteditable,
  &nsGkAtoms::contextmenu,
  &nsGkAtoms::controls,
  &nsGkAtoms::coords,
  &nsGkAtoms::datetime,
  &nsGkAtoms::dir,
  &nsGkAtoms::disabled,
  &nsGkAtoms::draggable,
  &nsGkAtoms::enctype,
  &nsGkAtoms::face,
  &nsGkAtoms::_for,
  &nsGkAtoms::frame,
  &nsGkAtoms::headers,
  &nsGkAtoms::height,
  &nsGkAtoms::hidden,
  &nsGkAtoms::high,
  &nsGkAtoms::href,
  &nsGkAtoms::hreflang,
  &nsGkAtoms::icon,
  &nsGkAtoms::id,
  &nsGkAtoms::ismap,
  &nsGkAtoms::itemid,
  &nsGkAtoms::itemprop,
  &nsGkAtoms::itemref,
  &nsGkAtoms::itemscope,
  &nsGkAtoms::itemtype,
  &nsGkAtoms::kind,
  &nsGkAtoms::label,
  &nsGkAtoms::lang,
  &nsGkAtoms::list,
  &nsGkAtoms::longdesc,
  &nsGkAtoms::loop,
  &nsGkAtoms::low,
  &nsGkAtoms::max,
  &nsGkAtoms::maxlength,
  &nsGkAtoms::media,
  &nsGkAtoms::method,
  &nsGkAtoms::min,
  &nsGkAtoms::mozdonotsend,
  &nsGkAtoms::multiple,
  &nsGkAtoms::muted,
  &nsGkAtoms::name,
  &nsGkAtoms::nohref,
  &nsGkAtoms::novalidate,
  &nsGkAtoms::nowrap,
  &nsGkAtoms::open,
  &nsGkAtoms::optimum,
  &nsGkAtoms::pattern,
  &nsGkAtoms::placeholder,
  &nsGkAtoms::playbackrate,
  &nsGkAtoms::poster,
  &nsGkAtoms::preload,
  &nsGkAtoms::prompt,
  &nsGkAtoms::pubdate,
  &nsGkAtoms::radiogroup,
  &nsGkAtoms::readonly,
  &nsGkAtoms::rel,
  &nsGkAtoms::required,
  &nsGkAtoms::rev,
  &nsGkAtoms::reversed,
  &nsGkAtoms::role,
  &nsGkAtoms::rows,
  &nsGkAtoms::rowspan,
  &nsGkAtoms::rules,
  &nsGkAtoms::scoped,
  &nsGkAtoms::scope,
  &nsGkAtoms::selected,
  &nsGkAtoms::shape,
  &nsGkAtoms::span,
  &nsGkAtoms::spellcheck,
  &nsGkAtoms::src,
  &nsGkAtoms::srclang,
  &nsGkAtoms::start,
  &nsGkAtoms::summary,
  &nsGkAtoms::tabindex,
  &nsGkAtoms::target,
  &nsGkAtoms::title,
  &nsGkAtoms::type,
  &nsGkAtoms::usemap,
  &nsGkAtoms::value,
  &nsGkAtoms::width,
  &nsGkAtoms::wrap,
  nullptr
};

nsIAtom** const kPresAttributesHTML[] = {
  &nsGkAtoms::align,
  &nsGkAtoms::background,
  &nsGkAtoms::bgcolor,
  &nsGkAtoms::border,
  &nsGkAtoms::cellpadding,
  &nsGkAtoms::cellspacing,
  &nsGkAtoms::color,
  &nsGkAtoms::compact,
  &nsGkAtoms::clear,
  &nsGkAtoms::hspace,
  &nsGkAtoms::noshade,
  &nsGkAtoms::pointSize,
  &nsGkAtoms::size,
  &nsGkAtoms::valign,
  &nsGkAtoms::vspace,
  nullptr
};

nsIAtom** const kURLAttributesHTML[] = {
  &nsGkAtoms::action,
  &nsGkAtoms::href,
  &nsGkAtoms::src,
  &nsGkAtoms::longdesc,
  &nsGkAtoms::cite,
  &nsGkAtoms::background,
  nullptr
};

nsIAtom** const kElementsSVG[] = {
  &nsGkAtoms::a, // a
  &nsGkAtoms::altGlyph, // altGlyph
  &nsGkAtoms::altGlyphDef, // altGlyphDef
  &nsGkAtoms::altGlyphItem, // altGlyphItem
  &nsGkAtoms::circle, // circle
  &nsGkAtoms::clipPath, // clipPath
  &nsGkAtoms::colorProfile, // color-profile
  &nsGkAtoms::cursor, // cursor
  &nsGkAtoms::defs, // defs
  &nsGkAtoms::desc, // desc
  &nsGkAtoms::ellipse, // ellipse
  &nsGkAtoms::elevation, // elevation
  &nsGkAtoms::erode, // erode
  &nsGkAtoms::ex, // ex
  &nsGkAtoms::exact, // exact
  &nsGkAtoms::exponent, // exponent
  &nsGkAtoms::feBlend, // feBlend
  &nsGkAtoms::feColorMatrix, // feColorMatrix
  &nsGkAtoms::feComponentTransfer, // feComponentTransfer
  &nsGkAtoms::feComposite, // feComposite
  &nsGkAtoms::feConvolveMatrix, // feConvolveMatrix
  &nsGkAtoms::feDiffuseLighting, // feDiffuseLighting
  &nsGkAtoms::feDisplacementMap, // feDisplacementMap
  &nsGkAtoms::feDistantLight, // feDistantLight
  &nsGkAtoms::feDropShadow, // feDropShadow
  &nsGkAtoms::feFlood, // feFlood
  &nsGkAtoms::feFuncA, // feFuncA
  &nsGkAtoms::feFuncB, // feFuncB
  &nsGkAtoms::feFuncG, // feFuncG
  &nsGkAtoms::feFuncR, // feFuncR
  &nsGkAtoms::feGaussianBlur, // feGaussianBlur
  &nsGkAtoms::feImage, // feImage
  &nsGkAtoms::feMerge, // feMerge
  &nsGkAtoms::feMergeNode, // feMergeNode
  &nsGkAtoms::feMorphology, // feMorphology
  &nsGkAtoms::feOffset, // feOffset
  &nsGkAtoms::fePointLight, // fePointLight
  &nsGkAtoms::feSpecularLighting, // feSpecularLighting
  &nsGkAtoms::feSpotLight, // feSpotLight
  &nsGkAtoms::feTile, // feTile
  &nsGkAtoms::feTurbulence, // feTurbulence
  &nsGkAtoms::filter, // filter
  &nsGkAtoms::font, // font
  &nsGkAtoms::font_face, // font-face
  &nsGkAtoms::font_face_format, // font-face-format
  &nsGkAtoms::font_face_name, // font-face-name
  &nsGkAtoms::font_face_src, // font-face-src
  &nsGkAtoms::font_face_uri, // font-face-uri
  &nsGkAtoms::foreignObject, // foreignObject
  &nsGkAtoms::g, // g
  &nsGkAtoms::glyph, // glyph
  &nsGkAtoms::glyphRef, // glyphRef
  &nsGkAtoms::hkern, // hkern
  &nsGkAtoms::image, // image
  &nsGkAtoms::line, // line
  &nsGkAtoms::linearGradient, // linearGradient
  &nsGkAtoms::marker, // marker
  &nsGkAtoms::mask, // mask
  &nsGkAtoms::metadata, // metadata
  &nsGkAtoms::missingGlyph, // missingGlyph
  &nsGkAtoms::mpath, // mpath
  &nsGkAtoms::path, // path
  &nsGkAtoms::pattern, // pattern
  &nsGkAtoms::polygon, // polygon
  &nsGkAtoms::polyline, // polyline
  &nsGkAtoms::radialGradient, // radialGradient
  &nsGkAtoms::rect, // rect
  &nsGkAtoms::stop, // stop
  &nsGkAtoms::svg, // svg
  &nsGkAtoms::svgSwitch, // switch
  &nsGkAtoms::symbol, // symbol
  &nsGkAtoms::text, // text
  &nsGkAtoms::textPath, // textPath
  &nsGkAtoms::title, // title
  &nsGkAtoms::tref, // tref
  &nsGkAtoms::tspan, // tspan
  &nsGkAtoms::use, // use
  &nsGkAtoms::view, // view
  &nsGkAtoms::vkern, // vkern
  nullptr
};

nsIAtom** const kAttributesSVG[] = {
  // accent-height
  &nsGkAtoms::accumulate, // accumulate
  &nsGkAtoms::additive, // additive
  &nsGkAtoms::alignment_baseline, // alignment-baseline
  // alphabetic
  &nsGkAtoms::amplitude, // amplitude
  // arabic-form
  // ascent
  &nsGkAtoms::attributeName, // attributeName
  &nsGkAtoms::attributeType, // attributeType
  &nsGkAtoms::azimuth, // azimuth
  &nsGkAtoms::baseFrequency, // baseFrequency
  &nsGkAtoms::baseline_shift, // baseline-shift
  // baseProfile
  // bbox
  &nsGkAtoms::begin, // begin
  &nsGkAtoms::bias, // bias
  &nsGkAtoms::by, // by
  &nsGkAtoms::calcMode, // calcMode
  // cap-height
  &nsGkAtoms::_class, // class
  &nsGkAtoms::clip_path, // clip-path
  &nsGkAtoms::clip_rule, // clip-rule
  &nsGkAtoms::clipPathUnits, // clipPathUnits
  &nsGkAtoms::color, // color
  &nsGkAtoms::colorInterpolation, // color-interpolation
  &nsGkAtoms::colorInterpolationFilters, // color-interpolation-filters
  &nsGkAtoms::cursor, // cursor
  &nsGkAtoms::cx, // cx
  &nsGkAtoms::cy, // cy
  &nsGkAtoms::d, // d
  // descent
  &nsGkAtoms::diffuseConstant, // diffuseConstant
  &nsGkAtoms::direction, // direction
  &nsGkAtoms::display, // display
  &nsGkAtoms::divisor, // divisor
  &nsGkAtoms::dominant_baseline, // dominant-baseline
  &nsGkAtoms::dur, // dur
  &nsGkAtoms::dx, // dx
  &nsGkAtoms::dy, // dy
  &nsGkAtoms::edgeMode, // edgeMode
  &nsGkAtoms::elevation, // elevation
  // enable-background
  &nsGkAtoms::end, // end
  &nsGkAtoms::fill, // fill
  &nsGkAtoms::fill_opacity, // fill-opacity
  &nsGkAtoms::fill_rule, // fill-rule
  &nsGkAtoms::filter, // filter
  &nsGkAtoms::filterUnits, // filterUnits
  &nsGkAtoms::flood_color, // flood-color
  &nsGkAtoms::flood_opacity, // flood-opacity
  // XXX focusable
  &nsGkAtoms::font, // font
  &nsGkAtoms::font_family, // font-family
  &nsGkAtoms::font_size, // font-size
  &nsGkAtoms::font_size_adjust, // font-size-adjust
  &nsGkAtoms::font_stretch, // font-stretch
  &nsGkAtoms::font_style, // font-style
  &nsGkAtoms::font_variant, // font-variant
  &nsGkAtoms::fontWeight, // font-weight
  &nsGkAtoms::format, // format
  &nsGkAtoms::from, // from
  &nsGkAtoms::fx, // fx
  &nsGkAtoms::fy, // fy
  // g1
  // g2
  // glyph-name
  // glyphRef
  &nsGkAtoms::glyph_orientation_horizontal, // glyph-orientation-horizontal
  &nsGkAtoms::glyph_orientation_vertical, // glyph-orientation-vertical
  &nsGkAtoms::gradientTransform, // gradientTransform
  &nsGkAtoms::gradientUnits, // gradientUnits
  &nsGkAtoms::height, // height
  // horiz-adv-x
  // horiz-origin-x
  // horiz-origin-y
  &nsGkAtoms::id, // id
  // ideographic
  &nsGkAtoms::image_rendering, // image-rendering
  &nsGkAtoms::in, // in
  &nsGkAtoms::in2, // in2
  &nsGkAtoms::intercept, // intercept
  // k
  &nsGkAtoms::k1, // k1
  &nsGkAtoms::k2, // k2
  &nsGkAtoms::k3, // k3
  &nsGkAtoms::k4, // k4
  &nsGkAtoms::kerning, // kerning
  &nsGkAtoms::kernelMatrix, // kernelMatrix
  &nsGkAtoms::kernelUnitLength, // kernelUnitLength
  &nsGkAtoms::keyPoints, // keyPoints
  &nsGkAtoms::keySplines, // keySplines
  &nsGkAtoms::keyTimes, // keyTimes
  &nsGkAtoms::lang, // lang
  // lengthAdjust
  &nsGkAtoms::letter_spacing, // letter-spacing
  &nsGkAtoms::lighting_color, // lighting-color
  &nsGkAtoms::limitingConeAngle, // limitingConeAngle
  // local
  &nsGkAtoms::marker, // marker
  &nsGkAtoms::marker_end, // marker-end
  &nsGkAtoms::marker_mid, // marker-mid
  &nsGkAtoms::marker_start, // marker-start
  &nsGkAtoms::markerHeight, // markerHeight
  &nsGkAtoms::markerUnits, // markerUnits
  &nsGkAtoms::markerWidth, // markerWidth
  &nsGkAtoms::mask, // mask
  &nsGkAtoms::maskContentUnits, // maskContentUnits
  &nsGkAtoms::maskUnits, // maskUnits
  // mathematical
  &nsGkAtoms::max, // max
  &nsGkAtoms::media, // media
  &nsGkAtoms::method, // method
  &nsGkAtoms::min, // min
  &nsGkAtoms::mode, // mode
  &nsGkAtoms::name, // name
  &nsGkAtoms::numOctaves, // numOctaves
  &nsGkAtoms::offset, // offset
  &nsGkAtoms::opacity, // opacity
  &nsGkAtoms::_operator, // operator
  &nsGkAtoms::order, // order
  &nsGkAtoms::orient, // orient
  &nsGkAtoms::orientation, // orientation
  // origin
  // overline-position
  // overline-thickness
  &nsGkAtoms::overflow, // overflow
  // panose-1
  &nsGkAtoms::path, // path
  &nsGkAtoms::pathLength, // pathLength
  &nsGkAtoms::patternContentUnits, // patternContentUnits
  &nsGkAtoms::patternTransform, // patternTransform
  &nsGkAtoms::patternUnits, // patternUnits
  &nsGkAtoms::pointer_events, // pointer-events XXX is this safe?
  &nsGkAtoms::points, // points
  &nsGkAtoms::pointsAtX, // pointsAtX
  &nsGkAtoms::pointsAtY, // pointsAtY
  &nsGkAtoms::pointsAtZ, // pointsAtZ
  &nsGkAtoms::preserveAlpha, // preserveAlpha
  &nsGkAtoms::preserveAspectRatio, // preserveAspectRatio
  &nsGkAtoms::primitiveUnits, // primitiveUnits
  &nsGkAtoms::r, // r
  &nsGkAtoms::radius, // radius
  &nsGkAtoms::refX, // refX
  &nsGkAtoms::refY, // refY
  &nsGkAtoms::repeatCount, // repeatCount
  &nsGkAtoms::repeatDur, // repeatDur
  &nsGkAtoms::requiredExtensions, // requiredExtensions
  &nsGkAtoms::requiredFeatures, // requiredFeatures
  &nsGkAtoms::restart, // restart
  &nsGkAtoms::result, // result
  &nsGkAtoms::rotate, // rotate
  &nsGkAtoms::rx, // rx
  &nsGkAtoms::ry, // ry
  &nsGkAtoms::scale, // scale
  &nsGkAtoms::seed, // seed
  &nsGkAtoms::shape_rendering, // shape-rendering
  &nsGkAtoms::slope, // slope
  &nsGkAtoms::spacing, // spacing
  &nsGkAtoms::specularConstant, // specularConstant
  &nsGkAtoms::specularExponent, // specularExponent
  &nsGkAtoms::spreadMethod, // spreadMethod
  &nsGkAtoms::startOffset, // startOffset
  &nsGkAtoms::stdDeviation, // stdDeviation
  // stemh
  // stemv
  &nsGkAtoms::stitchTiles, // stitchTiles
  &nsGkAtoms::stop_color, // stop-color
  &nsGkAtoms::stop_opacity, // stop-opacity
  // strikethrough-position
  // strikethrough-thickness
  &nsGkAtoms::string, // string
  &nsGkAtoms::stroke, // stroke
  &nsGkAtoms::stroke_dasharray, // stroke-dasharray
  &nsGkAtoms::stroke_dashoffset, // stroke-dashoffset
  &nsGkAtoms::stroke_linecap, // stroke-linecap
  &nsGkAtoms::stroke_linejoin, // stroke-linejoin
  &nsGkAtoms::stroke_miterlimit, // stroke-miterlimit
  &nsGkAtoms::stroke_opacity, // stroke-opacity
  &nsGkAtoms::stroke_width, // stroke-width
  &nsGkAtoms::surfaceScale, // surfaceScale
  &nsGkAtoms::systemLanguage, // systemLanguage
  &nsGkAtoms::tableValues, // tableValues
  &nsGkAtoms::target, // target
  &nsGkAtoms::targetX, // targetX
  &nsGkAtoms::targetY, // targetY
  &nsGkAtoms::text_anchor, // text-anchor
  &nsGkAtoms::text_decoration, // text-decoration
  // textLength
  &nsGkAtoms::text_rendering, // text-rendering
  &nsGkAtoms::title, // title
  &nsGkAtoms::to, // to
  &nsGkAtoms::transform, // transform
  &nsGkAtoms::type, // type
  // u1
  // u2
  // underline-position
  // underline-thickness
  // unicode
  &nsGkAtoms::unicode_bidi, // unicode-bidi
  // unicode-range
  // units-per-em
  // v-alphabetic
  // v-hanging
  // v-ideographic
  // v-mathematical
  &nsGkAtoms::values, // values
  &nsGkAtoms::vector_effect, // vector-effect
  // vert-adv-y
  // vert-origin-x
  // vert-origin-y
  &nsGkAtoms::viewBox, // viewBox
  &nsGkAtoms::viewTarget, // viewTarget
  &nsGkAtoms::visibility, // visibility
  &nsGkAtoms::width, // width
  // widths
  &nsGkAtoms::word_spacing, // word-spacing
  // writing-mode
  &nsGkAtoms::x, // x
  // x-height
  &nsGkAtoms::x1, // x1
  &nsGkAtoms::x2, // x2
  &nsGkAtoms::xChannelSelector, // xChannelSelector
  &nsGkAtoms::y, // y
  &nsGkAtoms::y1, // y1
  &nsGkAtoms::y2, // y2
  &nsGkAtoms::yChannelSelector, // yChannelSelector
  &nsGkAtoms::z, // z
  &nsGkAtoms::zoomAndPan, // zoomAndPan
  nullptr
};

nsIAtom** const kURLAttributesSVG[] = {
  nullptr
};

nsIAtom** const kElementsMathML[] = {
   &nsGkAtoms::abs_, // abs
   &nsGkAtoms::_and, // and
   &nsGkAtoms::annotation_, // annotation
   &nsGkAtoms::annotation_xml_, // annotation-xml
   &nsGkAtoms::apply_, // apply
   &nsGkAtoms::approx_, // approx
   &nsGkAtoms::arccos_, // arccos
   &nsGkAtoms::arccosh_, // arccosh
   &nsGkAtoms::arccot_, // arccot
   &nsGkAtoms::arccoth_, // arccoth
   &nsGkAtoms::arccsc_, // arccsc
   &nsGkAtoms::arccsch_, // arccsch
   &nsGkAtoms::arcsec_, // arcsec
   &nsGkAtoms::arcsech_, // arcsech
   &nsGkAtoms::arcsin_, // arcsin
   &nsGkAtoms::arcsinh_, // arcsinh
   &nsGkAtoms::arctan_, // arctan
   &nsGkAtoms::arctanh_, // arctanh
   &nsGkAtoms::arg_, // arg
   &nsGkAtoms::bind_, // bind
   &nsGkAtoms::bvar_, // bvar
   &nsGkAtoms::card_, // card
   &nsGkAtoms::cartesianproduct_, // cartesianproduct
   &nsGkAtoms::cbytes_, // cbytes
   &nsGkAtoms::ceiling, // ceiling
   &nsGkAtoms::cerror_, // cerror
   &nsGkAtoms::ci_, // ci
   &nsGkAtoms::cn_, // cn
   &nsGkAtoms::codomain_, // codomain
   &nsGkAtoms::complexes_, // complexes
   &nsGkAtoms::compose_, // compose
   &nsGkAtoms::condition_, // condition
   &nsGkAtoms::conjugate_, // conjugate
   &nsGkAtoms::cos_, // cos
   &nsGkAtoms::cosh_, // cosh
   &nsGkAtoms::cot_, // cot
   &nsGkAtoms::coth_, // coth
   &nsGkAtoms::cs_, // cs
   &nsGkAtoms::csc_, // csc
   &nsGkAtoms::csch_, // csch
   &nsGkAtoms::csymbol_, // csymbol
   &nsGkAtoms::curl_, // curl
   &nsGkAtoms::declare, // declare
   &nsGkAtoms::degree_, // degree
   &nsGkAtoms::determinant_, // determinant
   &nsGkAtoms::diff_, // diff
   &nsGkAtoms::divergence_, // divergence
   &nsGkAtoms::divide_, // divide
   &nsGkAtoms::domain_, // domain
   &nsGkAtoms::domainofapplication_, // domainofapplication
   &nsGkAtoms::el_, // el
   &nsGkAtoms::emptyset_, // emptyset
   &nsGkAtoms::eq_, // eq
   &nsGkAtoms::equivalent_, // equivalent
   &nsGkAtoms::eulergamma_, // eulergamma
   &nsGkAtoms::exists_, // exists
   &nsGkAtoms::exp_, // exp
   &nsGkAtoms::exponentiale_, // exponentiale
   &nsGkAtoms::factorial_, // factorial
   &nsGkAtoms::factorof_, // factorof
   &nsGkAtoms::_false, // false
   &nsGkAtoms::floor, // floor
   &nsGkAtoms::fn_, // fn
   &nsGkAtoms::forall_, // forall
   &nsGkAtoms::gcd_, // gcd
   &nsGkAtoms::geq_, // geq
   &nsGkAtoms::grad, // grad
   &nsGkAtoms::gt_, // gt
   &nsGkAtoms::ident_, // ident
   &nsGkAtoms::image, // image
   &nsGkAtoms::imaginary_, // imaginary
   &nsGkAtoms::imaginaryi_, // imaginaryi
   &nsGkAtoms::implies_, // implies
   &nsGkAtoms::in, // in
   &nsGkAtoms::infinity, // infinity
   &nsGkAtoms::int_, // int
   &nsGkAtoms::integers_, // integers
   &nsGkAtoms::intersect_, // intersect
   &nsGkAtoms::interval_, // interval
   &nsGkAtoms::inverse_, // inverse
   &nsGkAtoms::lambda_, // lambda
   &nsGkAtoms::laplacian_, // laplacian
   &nsGkAtoms::lcm_, // lcm
   &nsGkAtoms::leq_, // leq
   &nsGkAtoms::limit_, // limit
   &nsGkAtoms::list_, // list
   &nsGkAtoms::ln_, // ln
   &nsGkAtoms::log_, // log
   &nsGkAtoms::logbase_, // logbase
   &nsGkAtoms::lowlimit_, // lowlimit
   &nsGkAtoms::lt_, // lt
   &nsGkAtoms::maction_, // maction
   &nsGkAtoms::maligngroup_, // maligngroup
   &nsGkAtoms::malignmark_, // malignmark
   &nsGkAtoms::math, // math
   &nsGkAtoms::matrix, // matrix
   &nsGkAtoms::matrixrow_, // matrixrow
   &nsGkAtoms::max, // max
   &nsGkAtoms::mean_, // mean
   &nsGkAtoms::median_, // median
   &nsGkAtoms::menclose_, // menclose
   &nsGkAtoms::merror_, // merror
   &nsGkAtoms::mfenced_, // mfenced
   &nsGkAtoms::mfrac_, // mfrac
   &nsGkAtoms::mglyph_, // mglyph
   &nsGkAtoms::mi_, // mi
   &nsGkAtoms::min, // min
   &nsGkAtoms::minus_, // minus
   &nsGkAtoms::mlabeledtr_, // mlabeledtr
   &nsGkAtoms::mlongdiv_, // mlongdiv
   &nsGkAtoms::mmultiscripts_, // mmultiscripts
   &nsGkAtoms::mn_, // mn
   &nsGkAtoms::mo_, // mo
   &nsGkAtoms::mode, // mode
   &nsGkAtoms::moment_, // moment
   &nsGkAtoms::momentabout_, // momentabout
   &nsGkAtoms::mover_, // mover
   &nsGkAtoms::mpadded_, // mpadded
   &nsGkAtoms::mphantom_, // mphantom
   &nsGkAtoms::mprescripts_, // mprescripts
   &nsGkAtoms::mroot_, // mroot
   &nsGkAtoms::mrow_, // mrow
   &nsGkAtoms::ms_, // ms
   &nsGkAtoms::mscarries_, // mscarries
   &nsGkAtoms::mscarry_, // mscarry
   &nsGkAtoms::msgroup_, // msgroup
   &nsGkAtoms::msline_, // msline
   &nsGkAtoms::mspace_, // mspace
   &nsGkAtoms::msqrt_, // msqrt
   &nsGkAtoms::msrow_, // msrow
   &nsGkAtoms::mstack_, // mstack
   &nsGkAtoms::mstyle_, // mstyle
   &nsGkAtoms::msub_, // msub
   &nsGkAtoms::msubsup_, // msubsup
   &nsGkAtoms::msup_, // msup
   &nsGkAtoms::mtable_, // mtable
   &nsGkAtoms::mtd_, // mtd
   &nsGkAtoms::mtext_, // mtext
   &nsGkAtoms::mtr_, // mtr
   &nsGkAtoms::munder_, // munder
   &nsGkAtoms::munderover_, // munderover
   &nsGkAtoms::naturalnumbers_, // naturalnumbers
   &nsGkAtoms::neq_, // neq
   &nsGkAtoms::none, // none
   &nsGkAtoms::_not, // not
   &nsGkAtoms::notanumber_, // notanumber
   &nsGkAtoms::note_, // note
   &nsGkAtoms::notin_, // notin
   &nsGkAtoms::notprsubset_, // notprsubset
   &nsGkAtoms::notsubset_, // notsubset
   &nsGkAtoms::_or, // or
   &nsGkAtoms::otherwise, // otherwise
   &nsGkAtoms::outerproduct_, // outerproduct
   &nsGkAtoms::partialdiff_, // partialdiff
   &nsGkAtoms::pi_, // pi
   &nsGkAtoms::piece_, // piece
   &nsGkAtoms::piecewise_, // piecewise
   &nsGkAtoms::plus_, // plus
   &nsGkAtoms::power_, // power
   &nsGkAtoms::primes_, // primes
   &nsGkAtoms::product_, // product
   &nsGkAtoms::prsubset_, // prsubset
   &nsGkAtoms::quotient_, // quotient
   &nsGkAtoms::rationals_, // rationals
   &nsGkAtoms::real_, // real
   &nsGkAtoms::reals_, // reals
   &nsGkAtoms::reln_, // reln
   &nsGkAtoms::rem, // rem
   &nsGkAtoms::root_, // root
   &nsGkAtoms::scalarproduct_, // scalarproduct
   &nsGkAtoms::sdev_, // sdev
   &nsGkAtoms::sec_, // sec
   &nsGkAtoms::sech_, // sech
   &nsGkAtoms::selector_, // selector
   &nsGkAtoms::semantics_, // semantics
   &nsGkAtoms::sep_, // sep
   &nsGkAtoms::set_, // set
   &nsGkAtoms::setdiff_, // setdiff
   &nsGkAtoms::share_, // share
   &nsGkAtoms::sin_, // sin
   &nsGkAtoms::sinh_, // sinh
   &nsGkAtoms::subset_, // subset
   &nsGkAtoms::sum, // sum
   &nsGkAtoms::tan_, // tan
   &nsGkAtoms::tanh_, // tanh
   &nsGkAtoms::tendsto_, // tendsto
   &nsGkAtoms::times_, // times
   &nsGkAtoms::transpose_, // transpose
   &nsGkAtoms::_true, // true
   &nsGkAtoms::union_, // union
   &nsGkAtoms::uplimit_, // uplimit
   &nsGkAtoms::variance_, // variance
   &nsGkAtoms::vector_, // vector
   &nsGkAtoms::vectorproduct_, // vectorproduct
   &nsGkAtoms::xor_, // xor
  nullptr
};

nsIAtom** const kAttributesMathML[] = {
   &nsGkAtoms::accent_, // accent
   &nsGkAtoms::accentunder_, // accentunder
   &nsGkAtoms::actiontype_, // actiontype
   &nsGkAtoms::align, // align
   &nsGkAtoms::alignmentscope_, // alignmentscope
   &nsGkAtoms::alt, // alt
   &nsGkAtoms::altimg_, // altimg
   &nsGkAtoms::altimg_height_, // altimg-height
   &nsGkAtoms::altimg_valign_, // altimg-valign
   &nsGkAtoms::altimg_width_, // altimg-width
   &nsGkAtoms::background, // background
   &nsGkAtoms::base, // base
   &nsGkAtoms::bevelled_, // bevelled
   &nsGkAtoms::cd_, // cd
   &nsGkAtoms::cdgroup_, // cdgroup
   &nsGkAtoms::charalign_, // charalign
   &nsGkAtoms::close, // close
   &nsGkAtoms::closure_, // closure
   &nsGkAtoms::color, // color
   &nsGkAtoms::columnalign_, // columnalign
   &nsGkAtoms::columnalignment_, // columnalignment
   &nsGkAtoms::columnlines_, // columnlines
   &nsGkAtoms::columnspacing_, // columnspacing
   &nsGkAtoms::columnspan_, // columnspan
   &nsGkAtoms::columnwidth_, // columnwidth
   &nsGkAtoms::crossout_, // crossout
   &nsGkAtoms::decimalpoint_, // decimalpoint
   &nsGkAtoms::definitionURL_, // definitionURL
   &nsGkAtoms::denomalign_, // denomalign
   &nsGkAtoms::depth_, // depth
   &nsGkAtoms::dir, // dir
   &nsGkAtoms::display, // display
   &nsGkAtoms::displaystyle_, // displaystyle
   &nsGkAtoms::edge_, // edge
   &nsGkAtoms::encoding, // encoding
   &nsGkAtoms::equalcolumns_, // equalcolumns
   &nsGkAtoms::equalrows_, // equalrows
   &nsGkAtoms::fence_, // fence
   &nsGkAtoms::fontfamily_, // fontfamily
   &nsGkAtoms::fontsize_, // fontsize
   &nsGkAtoms::fontstyle_, // fontstyle
   &nsGkAtoms::fontweight_, // fontweight
   &nsGkAtoms::form, // form
   &nsGkAtoms::frame, // frame
   &nsGkAtoms::framespacing_, // framespacing
   &nsGkAtoms::groupalign_, // groupalign
   &nsGkAtoms::height, // height
   &nsGkAtoms::href, // href
   &nsGkAtoms::id, // id
   &nsGkAtoms::indentalign_, // indentalign
   &nsGkAtoms::indentalignfirst_, // indentalignfirst
   &nsGkAtoms::indentalignlast_, // indentalignlast
   &nsGkAtoms::indentshift_, // indentshift
   &nsGkAtoms::indentshiftfirst_, // indentshiftfirst
   &nsGkAtoms::indenttarget_, // indenttarget
   &nsGkAtoms::index, // index
   &nsGkAtoms::integer, // integer
   &nsGkAtoms::largeop_, // largeop
   &nsGkAtoms::length, // length
   &nsGkAtoms::linebreak_, // linebreak
   &nsGkAtoms::linebreakmultchar_, // linebreakmultchar
   &nsGkAtoms::linebreakstyle_, // linebreakstyle
   &nsGkAtoms::linethickness_, // linethickness
   &nsGkAtoms::location_, // location
   &nsGkAtoms::longdivstyle_, // longdivstyle
   &nsGkAtoms::lquote_, // lquote
   &nsGkAtoms::lspace_, // lspace
   &nsGkAtoms::ltr, // ltr
   &nsGkAtoms::mathbackground_, // mathbackground
   &nsGkAtoms::mathcolor_, // mathcolor
   &nsGkAtoms::mathsize_, // mathsize
   &nsGkAtoms::mathvariant_, // mathvariant
   &nsGkAtoms::maxsize_, // maxsize
   &nsGkAtoms::minlabelspacing_, // minlabelspacing
   &nsGkAtoms::minsize_, // minsize
   &nsGkAtoms::movablelimits_, // movablelimits
   &nsGkAtoms::msgroup_, // msgroup
   &nsGkAtoms::name, // name
   &nsGkAtoms::newline, // newline
   &nsGkAtoms::notation_, // notation
   &nsGkAtoms::numalign_, // numalign
   &nsGkAtoms::number, // number
   &nsGkAtoms::open, // open
   &nsGkAtoms::order, // order
   &nsGkAtoms::other_, // other
   &nsGkAtoms::overflow, // overflow
   &nsGkAtoms::position, // position
   &nsGkAtoms::role, // role
   &nsGkAtoms::rowalign_, // rowalign
   &nsGkAtoms::rowlines_, // rowlines
   &nsGkAtoms::rowspacing_, // rowspacing
   &nsGkAtoms::rowspan, // rowspan
   &nsGkAtoms::rquote_, // rquote
   &nsGkAtoms::rspace_, // rspace
   &nsGkAtoms::schemaLocation_, // schemaLocation
   &nsGkAtoms::scriptlevel_, // scriptlevel
   &nsGkAtoms::scriptminsize_, // scriptminsize
   &nsGkAtoms::scriptsize_, // scriptsize
   &nsGkAtoms::scriptsizemultiplier_, // scriptsizemultiplier
   &nsGkAtoms::selection_, // selection
   &nsGkAtoms::separator_, // separator
   &nsGkAtoms::separators_, // separators
   &nsGkAtoms::shift_, // shift
   &nsGkAtoms::side_, // side
   &nsGkAtoms::src, // src
   &nsGkAtoms::stackalign_, // stackalign
   &nsGkAtoms::stretchy_, // stretchy
   &nsGkAtoms::subscriptshift_, // subscriptshift
   &nsGkAtoms::superscriptshift_, // superscriptshift
   &nsGkAtoms::symmetric_, // symmetric
   &nsGkAtoms::type, // type
   &nsGkAtoms::voffset_, // voffset
   &nsGkAtoms::width, // width
   &nsGkAtoms::xref_, // xref
  nullptr
};

nsIAtom** const kURLAttributesMathML[] = {
  &nsGkAtoms::href,
  &nsGkAtoms::src,
  &nsGkAtoms::cdgroup_,
  &nsGkAtoms::altimg_,
  &nsGkAtoms::definitionURL_,
  nullptr
};

nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sElementsHTML = nullptr;
nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sAttributesHTML = nullptr;
nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sPresAttributesHTML = nullptr;
nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sElementsSVG = nullptr;
nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sAttributesSVG = nullptr;
nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sElementsMathML = nullptr;
nsTHashtable<nsISupportsHashKey>* nsTreeSanitizer::sAttributesMathML = nullptr;
nsIPrincipal* nsTreeSanitizer::sNullPrincipal = nullptr;

nsTreeSanitizer::nsTreeSanitizer(uint32_t aFlags)
 : mAllowStyles(aFlags & nsIParserUtils::SanitizerAllowStyle)
 , mAllowComments(aFlags & nsIParserUtils::SanitizerAllowComments)
 , mDropNonCSSPresentation(aFlags &
     nsIParserUtils::SanitizerDropNonCSSPresentation)
 , mDropForms(aFlags & nsIParserUtils::SanitizerDropForms)
 , mCidEmbedsOnly(aFlags &
     nsIParserUtils::SanitizerCidEmbedsOnly)
 , mDropMedia(aFlags & nsIParserUtils::SanitizerDropMedia)
 , mFullDocument(false)
{
  if (mCidEmbedsOnly) {
    // Sanitizing styles for external references is not supported.
    mAllowStyles = false;
  }
  if (!sElementsHTML) {
    // Initialize lazily to avoid having to initialize at all if the user
    // doesn't paste HTML or load feeds.
    InitializeStatics();
  }
}

bool
nsTreeSanitizer::MustFlatten(int32_t aNamespace, nsIAtom* aLocal)
{
  if (aNamespace == kNameSpaceID_XHTML) {
    if (mDropNonCSSPresentation && (nsGkAtoms::font == aLocal ||
                                    nsGkAtoms::center == aLocal)) {
      return true;
    }
    if (mDropForms && (nsGkAtoms::form == aLocal ||
                       nsGkAtoms::input == aLocal ||
                       nsGkAtoms::keygen == aLocal ||
                       nsGkAtoms::option == aLocal ||
                       nsGkAtoms::optgroup == aLocal)) {
      return true;
    }
    if (mFullDocument && (nsGkAtoms::title == aLocal ||
                          nsGkAtoms::html == aLocal ||
                          nsGkAtoms::head == aLocal ||
                          nsGkAtoms::body == aLocal)) {
      return false;
    }
    return !sElementsHTML->GetEntry(aLocal);
  }
  if (aNamespace == kNameSpaceID_SVG) {
    if (mCidEmbedsOnly || mDropMedia) {
      // Sanitizing CSS-based URL references inside SVG presentational
      // attributes is not supported, so flattening for cid: embed case.
      return true;
    }
    return !sElementsSVG->GetEntry(aLocal);
  }
  if (aNamespace == kNameSpaceID_MathML) {
    return !sElementsMathML->GetEntry(aLocal);
  }
  return true;
}

bool
nsTreeSanitizer::IsURL(nsIAtom*** aURLs, nsIAtom* aLocalName)
{
  nsIAtom** atomPtrPtr;
  while ((atomPtrPtr = *aURLs)) {
    if (*atomPtrPtr == aLocalName) {
      return true;
    }
    ++aURLs;
  }
  return false;
}

bool
nsTreeSanitizer::MustPrune(int32_t aNamespace,
                           nsIAtom* aLocal,
                           mozilla::dom::Element* aElement)
{
  // To avoid attacks where a MathML script becomes something that gets
  // serialized in a way that it parses back as an HTML script, let's just
  // drop elements with the local name 'script' regardless of namespace.
  if (nsGkAtoms::script == aLocal) {
    return true;
  }
  if (aNamespace == kNameSpaceID_XHTML) {
    if (nsGkAtoms::title == aLocal && !mFullDocument) {
      // emulate the quirks of the old parser
      return true;
    }
    if (mDropForms && (nsGkAtoms::select == aLocal ||
                       nsGkAtoms::button == aLocal ||
                       nsGkAtoms::datalist == aLocal)) {
      return true;
    }
    if (mDropMedia && (nsGkAtoms::img == aLocal ||
                       nsGkAtoms::video == aLocal ||
                       nsGkAtoms::audio == aLocal ||
                       nsGkAtoms::source == aLocal)) {
      return true;
    }
    if (nsGkAtoms::meta == aLocal &&
        (aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::charset) ||
         aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::httpEquiv))) {
      // Throw away charset declarations even if they also have microdata
      // which they can't validly have.
      return true;
    }
    if (((!mFullDocument && nsGkAtoms::meta == aLocal) ||
        nsGkAtoms::link == aLocal) &&
        !(aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::itemprop) ||
          aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::itemscope))) {
      // emulate old behavior for non-Microdata <meta> and <link> presumably
      // in <head>. <meta> and <link> are whitelisted in order to avoid
      // corrupting Microdata when they appear in <body>. Note that
      // SanitizeAttributes() will remove the rel attribute from <link> and
      // the name attribute from <meta>.
      return true;
    }
  }
  if (mAllowStyles) {
    if (nsGkAtoms::style == aLocal && !(aNamespace == kNameSpaceID_XHTML
        || aNamespace == kNameSpaceID_SVG)) {
      return true;
    }
    return false;
  }
  if (nsGkAtoms::style == aLocal) {
    return true;
  }
  return false;
}

bool
nsTreeSanitizer::SanitizeStyleDeclaration(mozilla::css::Declaration* aDeclaration,
                                          nsAutoString& aRuleText)
{
  bool didSanitize = aDeclaration->HasProperty(eCSSProperty_binding);
  aDeclaration->RemoveProperty(eCSSProperty_binding);
  aDeclaration->ToString(aRuleText);
  return didSanitize;
}

bool
nsTreeSanitizer::SanitizeStyleSheet(const nsAString& aOriginal,
                                    nsAString& aSanitized,
                                    nsIDocument* aDocument,
                                    nsIURI* aBaseURI)
{
  nsresult rv;
  aSanitized.Truncate();
  // aSanitized will hold the permitted CSS text.
  // -moz-binding is blacklisted.
  bool didSanitize = false;
  // Create a sheet to hold the parsed CSS
  RefPtr<CSSStyleSheet> sheet = new CSSStyleSheet(CORS_NONE, aDocument->GetReferrerPolicy());
  sheet->SetURIs(aDocument->GetDocumentURI(), nullptr, aBaseURI);
  sheet->SetPrincipal(aDocument->NodePrincipal());
  // Create the CSS parser, and parse the CSS text.
  nsCSSParser parser(nullptr, sheet);
  rv = parser.ParseSheet(aOriginal, aDocument->GetDocumentURI(), aBaseURI,
                         aDocument->NodePrincipal(), 0,
                         mozilla::css::eAuthorSheetFeatures);
  NS_ENSURE_SUCCESS(rv, true);
  // Mark the sheet as complete.
  MOZ_ASSERT(!sheet->IsModified(),
             "should not get marked modified during parsing");
  sheet->SetComplete();
  // Loop through all the rules found in the CSS text
  int32_t ruleCount = sheet->StyleRuleCount();
  for (int32_t i = 0; i < ruleCount; ++i) {
    mozilla::css::Rule* rule = sheet->GetStyleRuleAt(i);
    if (!rule)
      continue;
    switch (rule->GetType()) {
      default:
        didSanitize = true;
        // Ignore these rule types.
        break;
      case mozilla::css::Rule::NAMESPACE_RULE:
      case mozilla::css::Rule::FONT_FACE_RULE: {
        // Append @namespace and @font-face rules verbatim.
        nsAutoString cssText;
        nsCOMPtr<nsIDOMCSSRule> styleRule = do_QueryInterface(rule);
        if (styleRule) {
          rv = styleRule->GetCssText(cssText);
          if (NS_SUCCEEDED(rv)) {
            aSanitized.Append(cssText);
          }
        }
        break;
      }
      case mozilla::css::Rule::STYLE_RULE: {
        // For style rules, we will just look for and remove the
        // -moz-binding properties.
        RefPtr<mozilla::css::StyleRule> styleRule = do_QueryObject(rule);
        NS_ASSERTION(styleRule, "Must be a style rule");
        nsAutoString decl;
        bool sanitized =
          SanitizeStyleDeclaration(styleRule->GetDeclaration(), decl);
        didSanitize = sanitized || didSanitize;
        if (!sanitized) {
          styleRule->GetCssText(decl);
        }
        aSanitized.Append(decl);
      }
    }
  }
  return didSanitize;
}

void
nsTreeSanitizer::SanitizeAttributes(mozilla::dom::Element* aElement,
                                    nsTHashtable<nsISupportsHashKey>* aAllowed,
                                    nsIAtom*** aURLs,
                                    bool aAllowXLink,
                                    bool aAllowStyle,
                                    bool aAllowDangerousSrc)
{
  uint32_t ac = aElement->GetAttrCount();

  for (int32_t i = ac - 1; i >= 0; --i) {
    const nsAttrName* attrName = aElement->GetAttrNameAt(i);
    int32_t attrNs = attrName->NamespaceID();
    nsCOMPtr<nsIAtom> attrLocal = attrName->LocalName();

    if (kNameSpaceID_None == attrNs) {
      if (aAllowStyle && nsGkAtoms::style == attrLocal) {
        nsCOMPtr<nsIURI> baseURI = aElement->GetBaseURI();
        nsIDocument* document = aElement->OwnerDoc();
        // Pass the CSS Loader object to the parser, to allow parser error
        // reports to include the outer window ID.
        nsCSSParser parser(document->CSSLoader());
        nsAutoString value;
        aElement->GetAttr(attrNs, attrLocal, value);
        RefPtr<mozilla::css::Declaration> decl =
          parser.ParseStyleAttribute(value, document->GetDocumentURI(),
                                     baseURI, document->NodePrincipal());
        if (decl) {
          nsAutoString cleanValue;
          if (SanitizeStyleDeclaration(decl, cleanValue)) {
            aElement->SetAttr(kNameSpaceID_None,
                              nsGkAtoms::style,
                              cleanValue,
                              false);
          }
        }
        continue;
      }
      if (aAllowDangerousSrc && nsGkAtoms::src == attrLocal) {
        continue;
      }
      if (IsURL(aURLs, attrLocal)) {
        if (SanitizeURL(aElement, attrNs, attrLocal)) {
          // in case the attribute removal shuffled the attribute order, start
          // the loop again.
          --ac;
          i = ac; // i will be decremented immediately thanks to the for loop
          continue;
        }
        // else fall through to see if there's another reason to drop this
        // attribute (in particular if the attribute is background="" on an
        // HTML element)
      }
      if (!mDropNonCSSPresentation &&
          (aAllowed == sAttributesHTML) && // element is HTML
          sPresAttributesHTML->GetEntry(attrLocal)) {
        continue;
      }
      if (aAllowed->GetEntry(attrLocal) &&
          !((attrLocal == nsGkAtoms::rel &&
             aElement->IsHTMLElement(nsGkAtoms::link)) ||
            (!mFullDocument &&
             attrLocal == nsGkAtoms::name &&
             aElement->IsHTMLElement(nsGkAtoms::meta)))) {
        // name="" and rel="" are whitelisted, but treat them as blacklisted
        // for <meta name> (fragment case) and <link rel> (all cases) to avoid
        // document-wide metadata or styling overrides with non-conforming
        // <meta name itemprop> or
        // <link rel itemprop>
        continue;
      }
      const char16_t* localStr = attrLocal->GetUTF16String();
      // Allow underscore to cater to the MCE editor library.
      // Allow data-* on SVG and MathML, too, as a forward-compat measure.
      if (*localStr == '_' || (attrLocal->GetLength() > 5 && localStr[0] == 'd'
          && localStr[1] == 'a' && localStr[2] == 't' && localStr[3] == 'a'
          && localStr[4] == '-')) {
        continue;
      }
      // else not allowed
    } else if (kNameSpaceID_XML == attrNs) {
      if (nsGkAtoms::base == attrLocal) {
        if (SanitizeURL(aElement, attrNs, attrLocal)) {
          // in case the attribute removal shuffled the attribute order, start
          // the loop again.
          --ac;
          i = ac; // i will be decremented immediately thanks to the for loop
        }
        continue;
      }
      if (nsGkAtoms::lang == attrLocal || nsGkAtoms::space == attrLocal) {
        continue;
      }
      // else not allowed
    } else if (aAllowXLink && kNameSpaceID_XLink == attrNs) {
      if (nsGkAtoms::href == attrLocal) {
        if (SanitizeURL(aElement, attrNs, attrLocal)) {
          // in case the attribute removal shuffled the attribute order, start
          // the loop again.
          --ac;
          i = ac; // i will be decremented immediately thanks to the for loop
        }
        continue;
      }
      if (nsGkAtoms::type == attrLocal || nsGkAtoms::title == attrLocal
          || nsGkAtoms::show == attrLocal || nsGkAtoms::actuate == attrLocal) {
        continue;
      }
      // else not allowed
    }
    aElement->UnsetAttr(kNameSpaceID_None, attrLocal, false);
    // in case the attribute removal shuffled the attribute order, start the
    // loop again.
    --ac;
    i = ac; // i will be decremented immediately thanks to the for loop
  }

  // If we've got HTML audio or video, add the controls attribute, because
  // otherwise the content is unplayable with scripts removed.
  if (aElement->IsAnyOfHTMLElements(nsGkAtoms::video, nsGkAtoms::audio)) {
    aElement->SetAttr(kNameSpaceID_None,
                      nsGkAtoms::controls,
                      EmptyString(),
                      false);
  }
}

bool
nsTreeSanitizer::SanitizeURL(mozilla::dom::Element* aElement,
                             int32_t aNamespace,
                             nsIAtom* aLocalName)
{
  nsAutoString value;
  aElement->GetAttr(aNamespace, aLocalName, value);

  // Get value and remove mandatory quotes
  static const char* kWhitespace = "\n\r\t\b";
  const nsAString& v =
    nsContentUtils::TrimCharsInSet(kWhitespace, value);

  nsIScriptSecurityManager* secMan = nsContentUtils::GetSecurityManager();
  uint32_t flags = nsIScriptSecurityManager::DISALLOW_INHERIT_PRINCIPAL;

  nsCOMPtr<nsIURI> baseURI = aElement->GetBaseURI();
  nsCOMPtr<nsIURI> attrURI;
  nsresult rv = NS_NewURI(getter_AddRefs(attrURI), v, nullptr, baseURI);
  if (NS_SUCCEEDED(rv)) { 
    if (mCidEmbedsOnly &&
        kNameSpaceID_None == aNamespace) {
      if (nsGkAtoms::src == aLocalName || nsGkAtoms::background == aLocalName) {
        // comm-central uses a hack that makes nsIURIs created with cid: specs
        // actually have an about:blank spec. Therefore, nsIURI facilities are
        // useless for cid: when comm-central code is participating.
        if (!(v.Length() > 4 &&
              (v[0] == 'c' || v[0] == 'C') &&
              (v[1] == 'i' || v[1] == 'I') &&
              (v[2] == 'd' || v[2] == 'D') &&
              v[3] == ':')) {
          rv = NS_ERROR_FAILURE;
        }
      } else if (nsGkAtoms::cdgroup_ == aLocalName ||
                 nsGkAtoms::altimg_ == aLocalName ||
                 nsGkAtoms::definitionURL_ == aLocalName) {
        // Gecko doesn't fetch these now and shouldn't in the future, but
        // in case someone goofs with these in the future, let's drop them.
        rv = NS_ERROR_FAILURE;
      } else {
        rv = secMan->CheckLoadURIWithPrincipal(sNullPrincipal, attrURI, flags);
      }
    } else {
      rv = secMan->CheckLoadURIWithPrincipal(sNullPrincipal, attrURI, flags);
    }
  }
  if (NS_FAILED(rv)) {
    aElement->UnsetAttr(aNamespace, aLocalName, false);
    return true;
  }
  return false;
}

void
nsTreeSanitizer::Sanitize(nsIContent* aFragment)
{
  // If you want to relax these preconditions, be sure to check the code in
  // here that notifies / does not notify or that fires mutation events if
  // in tree.
  NS_PRECONDITION(aFragment->IsNodeOfType(nsINode::eDOCUMENT_FRAGMENT),
      "Argument was not DOM fragment.");
  NS_PRECONDITION(!aFragment->IsInDoc(), "The fragment is in doc?");

  mFullDocument = false;
  SanitizeChildren(aFragment);
}

void
nsTreeSanitizer::Sanitize(nsIDocument* aDocument)
{
  // If you want to relax these preconditions, be sure to check the code in
  // here that notifies / does not notify or that fires mutation events if
  // in tree.
#ifdef DEBUG
  NS_PRECONDITION(!aDocument->GetContainer(), "The document is in a shell.");
  RefPtr<mozilla::dom::Element> root = aDocument->GetRootElement();
  NS_PRECONDITION(root->IsHTMLElement(nsGkAtoms::html), "Not HTML root.");
#endif

  mFullDocument = true;
  SanitizeChildren(aDocument);
}

void
nsTreeSanitizer::SanitizeChildren(nsINode* aRoot)
{
  nsIContent* node = aRoot->GetFirstChild();
  while (node) {
    if (node->IsElement()) {
      mozilla::dom::Element* elt = node->AsElement();
      mozilla::dom::NodeInfo* nodeInfo = node->NodeInfo();
      nsIAtom* localName = nodeInfo->NameAtom();
      int32_t ns = nodeInfo->NamespaceID();

      if (MustPrune(ns, localName, elt)) {
        RemoveAllAttributes(node);
        nsIContent* descendant = node;
        while ((descendant = descendant->GetNextNode(node))) {
          RemoveAllAttributes(descendant);
        }
        nsIContent* next = node->GetNextNonChildNode(aRoot);
        node->RemoveFromParent();
        node = next;
        continue;
      }
      if (nsGkAtoms::style == localName) {
        // If styles aren't allowed, style elements got pruned above. Even
        // if styles are allowed, non-HTML, non-SVG style elements got pruned
        // above.
        NS_ASSERTION(ns == kNameSpaceID_XHTML || ns == kNameSpaceID_SVG,
            "Should have only HTML or SVG here!");
        nsAutoString styleText;
        nsContentUtils::GetNodeTextContent(node, false, styleText);

        nsAutoString sanitizedStyle;
        nsCOMPtr<nsIURI> baseURI = node->GetBaseURI();
        if (SanitizeStyleSheet(styleText,
                               sanitizedStyle,
                               aRoot->OwnerDoc(),
                               baseURI)) {
          nsContentUtils::SetNodeTextContent(node, sanitizedStyle, true);
        } else {
          // If the node had non-text child nodes, this operation zaps those.
          nsContentUtils::SetNodeTextContent(node, styleText, true);
        }
        if (ns == kNameSpaceID_XHTML) {
          SanitizeAttributes(elt,
                             sAttributesHTML,
                             (nsIAtom***)kURLAttributesHTML,
                             false,
                             mAllowStyles,
                             false);
        } else {
          SanitizeAttributes(elt,
                             sAttributesSVG,
                             (nsIAtom***)kURLAttributesSVG,
                             true,
                             mAllowStyles,
                             false);
        }
        node = node->GetNextNonChildNode(aRoot);
        continue;
      }
      if (MustFlatten(ns, localName)) {
        RemoveAllAttributes(node);
        nsCOMPtr<nsIContent> next = node->GetNextNode(aRoot);
        nsCOMPtr<nsIContent> parent = node->GetParent();
        nsCOMPtr<nsIContent> child; // Must keep the child alive during move
        ErrorResult rv;
        while ((child = node->GetFirstChild())) {
          nsCOMPtr<nsINode> refNode = node;
          parent->InsertBefore(*child, refNode, rv);
          if (rv.Failed()) {
            break;
          }
        }
        node->RemoveFromParent();
        node = next;
        continue;
      }
      NS_ASSERTION(ns == kNameSpaceID_XHTML ||
                   ns == kNameSpaceID_SVG ||
                   ns == kNameSpaceID_MathML,
          "Should have only HTML, MathML or SVG here!");
      if (ns == kNameSpaceID_XHTML) {
        SanitizeAttributes(elt,
                           sAttributesHTML,
                           (nsIAtom***)kURLAttributesHTML,
                           false, mAllowStyles,
                           (nsGkAtoms::img == localName) &&
                           !mCidEmbedsOnly);
      } else if (ns == kNameSpaceID_SVG) {
        SanitizeAttributes(elt,
                           sAttributesSVG,
                           (nsIAtom***)kURLAttributesSVG,
                           true,
                           mAllowStyles,
                           false);
      } else {
        SanitizeAttributes(elt,
                           sAttributesMathML,
                           (nsIAtom***)kURLAttributesMathML,
                           true,
                           false,
                           false);
      }
      node = node->GetNextNode(aRoot);
      continue;
    }
    NS_ASSERTION(!node->GetFirstChild(), "How come non-element node had kids?");
    nsIContent* next = node->GetNextNonChildNode(aRoot);
    if (!mAllowComments && node->IsNodeOfType(nsINode::eCOMMENT)) {
      node->RemoveFromParent();
    }
    node = next;
  }
}

void
nsTreeSanitizer::RemoveAllAttributes(nsIContent* aElement)
{
  const nsAttrName* attrName;
  while ((attrName = aElement->GetAttrNameAt(0))) {
    int32_t attrNs = attrName->NamespaceID();
    nsCOMPtr<nsIAtom> attrLocal = attrName->LocalName();
    aElement->UnsetAttr(attrNs, attrLocal, false);
  }
}

void
nsTreeSanitizer::InitializeStatics()
{
  NS_PRECONDITION(!sElementsHTML, "Initializing a second time.");

  sElementsHTML = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kElementsHTML));
  for (uint32_t i = 0; kElementsHTML[i]; i++) {
    sElementsHTML->PutEntry(*kElementsHTML[i]);
  }

  sAttributesHTML = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kAttributesHTML));
  for (uint32_t i = 0; kAttributesHTML[i]; i++) {
    sAttributesHTML->PutEntry(*kAttributesHTML[i]);
  }

  sPresAttributesHTML = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kPresAttributesHTML));
  for (uint32_t i = 0; kPresAttributesHTML[i]; i++) {
    sPresAttributesHTML->PutEntry(*kPresAttributesHTML[i]);
  }

  sElementsSVG = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kElementsSVG));
  for (uint32_t i = 0; kElementsSVG[i]; i++) {
    sElementsSVG->PutEntry(*kElementsSVG[i]);
  }

  sAttributesSVG = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kAttributesSVG));
  for (uint32_t i = 0; kAttributesSVG[i]; i++) {
    sAttributesSVG->PutEntry(*kAttributesSVG[i]);
  }

  sElementsMathML = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kElementsMathML));
  for (uint32_t i = 0; kElementsMathML[i]; i++) {
    sElementsMathML->PutEntry(*kElementsMathML[i]);
  }

  sAttributesMathML = new nsTHashtable<nsISupportsHashKey>(ArrayLength(kAttributesMathML));
  for (uint32_t i = 0; kAttributesMathML[i]; i++) {
    sAttributesMathML->PutEntry(*kAttributesMathML[i]);
  }

  nsCOMPtr<nsIPrincipal> principal =
      do_CreateInstance(NS_NULLPRINCIPAL_CONTRACTID);
  principal.forget(&sNullPrincipal);
}

void
nsTreeSanitizer::ReleaseStatics()
{
  delete sElementsHTML;
  sElementsHTML = nullptr;

  delete sAttributesHTML;
  sAttributesHTML = nullptr;

  delete sPresAttributesHTML;
  sPresAttributesHTML = nullptr;

  delete sElementsSVG;
  sElementsSVG = nullptr;

  delete sAttributesSVG;
  sAttributesSVG = nullptr;

  delete sElementsMathML;
  sElementsMathML = nullptr;

  delete sAttributesMathML;
  sAttributesMathML = nullptr;

  NS_IF_RELEASE(sNullPrincipal);
}
