gecko-dev/editor/libeditor/HTMLEditUtils.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "HTMLEditUtils.h"

#include "mozilla/ArrayUtils.h"   // for ArrayLength
#include "mozilla/Assertions.h"   // for MOZ_ASSERT, etc.
#include "mozilla/EditAction.h"   // for EditAction
#include "mozilla/EditorBase.h"   // for EditorBase
#include "mozilla/dom/Element.h"  // for Element, nsINode
#include "nsAString.h"            // for nsAString::IsEmpty
#include "nsCOMPtr.h"             // for nsCOMPtr, operator==, etc.
#include "nsCaseTreatment.h"
#include "nsDebug.h"    // for NS_ASSERTION, etc.
#include "nsError.h"    // for NS_SUCCEEDED
#include "nsGkAtoms.h"  // for nsGkAtoms, nsGkAtoms::a, etc.
#include "nsHTMLTags.h"
#include "nsAtom.h"              // for nsAtom
#include "nsNameSpaceManager.h"  // for kNameSpaceID_None
#include "nsLiteralString.h"     // for NS_LITERAL_STRING
#include "nsString.h"            // for nsAutoString
#include "mozilla/dom/HTMLAnchorElement.h"

namespace mozilla {

/**
 * IsInlineStyle() returns true if aNode is an inline style.
 */
bool HTMLEditUtils::IsInlineStyle(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(
      nsGkAtoms::b, nsGkAtoms::i, nsGkAtoms::u, nsGkAtoms::tt, nsGkAtoms::s,
      nsGkAtoms::strike, nsGkAtoms::big, nsGkAtoms::small, nsGkAtoms::sub,
      nsGkAtoms::sup, nsGkAtoms::font);
}

bool HTMLEditUtils::IsRemovableInlineStyleElement(Element& aElement) {
  if (!aElement.IsHTMLElement()) {
    return false;
  }
  // https://w3c.github.io/editing/execCommand.html#removeformat-candidate
  if (aElement.IsAnyOfHTMLElements(
          nsGkAtoms::abbr,  // Chrome ignores, but does not make sense.
          nsGkAtoms::acronym, nsGkAtoms::b,
          nsGkAtoms::bdi,  // Chrome ignores, but does not make sense.
          nsGkAtoms::bdo, nsGkAtoms::big, nsGkAtoms::cite, nsGkAtoms::code,
          // nsGkAtoms::del, Chrome ignores, but does not make sense but
          // execCommand unofficial draft excludes this.  Spec issue:
          // https://github.com/w3c/editing/issues/192
          nsGkAtoms::dfn, nsGkAtoms::em, nsGkAtoms::font, nsGkAtoms::i,
          nsGkAtoms::ins, nsGkAtoms::kbd,
          nsGkAtoms::mark,  // Chrome ignores, but does not make sense.
          nsGkAtoms::nobr, nsGkAtoms::q, nsGkAtoms::s, nsGkAtoms::samp,
          nsGkAtoms::small, nsGkAtoms::span, nsGkAtoms::strike,
          nsGkAtoms::strong, nsGkAtoms::sub, nsGkAtoms::sup, nsGkAtoms::tt,
          nsGkAtoms::u, nsGkAtoms::var)) {
    return true;
  }
  // If it's a <blink> element, we can remove it.
  nsAutoString tagName;
  aElement.GetTagName(tagName);
  return tagName.LowerCaseEqualsASCII("blink");
}

/**
 * IsFormatNode() returns true if aNode is a format node.
 */
bool HTMLEditUtils::IsFormatNode(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(
      nsGkAtoms::p, nsGkAtoms::pre, nsGkAtoms::h1, nsGkAtoms::h2, nsGkAtoms::h3,
      nsGkAtoms::h4, nsGkAtoms::h5, nsGkAtoms::h6, nsGkAtoms::address);
}

/**
 * IsNodeThatCanOutdent() returns true if aNode is a list, list item or
 * blockquote.
 */
bool HTMLEditUtils::IsNodeThatCanOutdent(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(nsGkAtoms::ul, nsGkAtoms::ol, nsGkAtoms::dl,
                                    nsGkAtoms::li, nsGkAtoms::dd, nsGkAtoms::dt,
                                    nsGkAtoms::blockquote);
}

/**
 * IsHeader() returns true if aNode is an html header.
 */
bool HTMLEditUtils::IsHeader(nsINode& aNode) {
  return aNode.IsAnyOfHTMLElements(nsGkAtoms::h1, nsGkAtoms::h2, nsGkAtoms::h3,
                                   nsGkAtoms::h4, nsGkAtoms::h5, nsGkAtoms::h6);
}

/**
 * IsListItem() returns true if aNode is an html list item.
 */
bool HTMLEditUtils::IsListItem(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(nsGkAtoms::li, nsGkAtoms::dd,
                                    nsGkAtoms::dt);
}

/**
 * IsTableElement() returns true if aNode is an html table, td, tr, ...
 */
bool HTMLEditUtils::IsTableElement(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(
      nsGkAtoms::table, nsGkAtoms::tr, nsGkAtoms::td, nsGkAtoms::th,
      nsGkAtoms::thead, nsGkAtoms::tfoot, nsGkAtoms::tbody, nsGkAtoms::caption);
}

/**
 * IsTableElementButNotTable() returns true if aNode is an html td, tr, ...
 * (doesn't include table)
 */
bool HTMLEditUtils::IsTableElementButNotTable(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(nsGkAtoms::tr, nsGkAtoms::td, nsGkAtoms::th,
                                    nsGkAtoms::thead, nsGkAtoms::tfoot,
                                    nsGkAtoms::tbody, nsGkAtoms::caption);
}

/**
 * IsTable() returns true if aNode is an html table.
 */
bool HTMLEditUtils::IsTable(nsINode* aNode) {
  return aNode && aNode->IsHTMLElement(nsGkAtoms::table);
}

/**
 * IsTableRow() returns true if aNode is an html tr.
 */
bool HTMLEditUtils::IsTableRow(nsINode* aNode) {
  return aNode && aNode->IsHTMLElement(nsGkAtoms::tr);
}

/**
 * IsTableCell() returns true if aNode is an html td or th.
 */
bool HTMLEditUtils::IsTableCell(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(nsGkAtoms::td, nsGkAtoms::th);
}

/**
 * IsTableCellOrCaption() returns true if aNode is an html td or th or caption.
 */
bool HTMLEditUtils::IsTableCellOrCaption(nsINode& aNode) {
  return aNode.IsAnyOfHTMLElements(nsGkAtoms::td, nsGkAtoms::th,
                                   nsGkAtoms::caption);
}

/**
 * IsList() returns true if aNode is an html list.
 */
bool HTMLEditUtils::IsList(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(nsGkAtoms::ul, nsGkAtoms::ol,
                                    nsGkAtoms::dl);
}

/**
 * IsPre() returns true if aNode is an html pre node.
 */
bool HTMLEditUtils::IsPre(nsINode* aNode) {
  return aNode && aNode->IsHTMLElement(nsGkAtoms::pre);
}

/**
 * IsImage() returns true if aNode is an html image node.
 */
bool HTMLEditUtils::IsImage(nsINode* aNode) {
  return aNode && aNode->IsHTMLElement(nsGkAtoms::img);
}

bool HTMLEditUtils::IsLink(nsINode* aNode) {
  MOZ_ASSERT(aNode);

  if (!aNode->IsContent()) {
    return false;
  }

  RefPtr<HTMLAnchorElement> anchor =
      HTMLAnchorElement::FromNodeOrNull(aNode->AsContent());
  if (!anchor) {
    return false;
  }

  nsAutoString tmpText;
  anchor->GetHref(tmpText);
  return !tmpText.IsEmpty();
}

bool HTMLEditUtils::IsNamedAnchor(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  if (!aNode->IsHTMLElement(nsGkAtoms::a)) {
    return false;
  }

  nsAutoString text;
  return aNode->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::name,
                                     text) &&
         !text.IsEmpty();
}

/**
 * IsMozDiv() returns true if aNode is an html div node with |type = _moz|.
 */
bool HTMLEditUtils::IsMozDiv(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsHTMLElement(nsGkAtoms::div) &&
         aNode->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::type,
                                         NS_LITERAL_STRING("_moz"),
                                         eIgnoreCase);
}

/**
 * IsMailCite() returns true if aNode is an html blockquote with |type=cite|.
 */
bool HTMLEditUtils::IsMailCite(nsINode* aNode) {
  MOZ_ASSERT(aNode);

  // don't ask me why, but our html mailcites are id'd by "type=cite"...
  if (aNode->IsElement() &&
      aNode->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::type,
                                      NS_LITERAL_STRING("cite"), eIgnoreCase)) {
    return true;
  }

  // ... but our plaintext mailcites by "_moz_quote=true".  go figure.
  if (aNode->IsElement() &&
      aNode->AsElement()->AttrValueIs(kNameSpaceID_None, nsGkAtoms::mozquote,
                                      NS_LITERAL_STRING("true"), eIgnoreCase)) {
    return true;
  }

  return false;
}

/**
 * IsFormWidget() returns true if aNode is a form widget of some kind.
 */
bool HTMLEditUtils::IsFormWidget(nsINode* aNode) {
  MOZ_ASSERT(aNode);
  return aNode->IsAnyOfHTMLElements(nsGkAtoms::textarea, nsGkAtoms::select,
                                    nsGkAtoms::button, nsGkAtoms::output,
                                    nsGkAtoms::progress, nsGkAtoms::meter,
                                    nsGkAtoms::input);
}

bool HTMLEditUtils::SupportsAlignAttr(nsINode& aNode) {
  return aNode.IsAnyOfHTMLElements(
      nsGkAtoms::hr, nsGkAtoms::table, nsGkAtoms::tbody, nsGkAtoms::tfoot,
      nsGkAtoms::thead, nsGkAtoms::tr, nsGkAtoms::td, nsGkAtoms::th,
      nsGkAtoms::div, nsGkAtoms::p, nsGkAtoms::h1, nsGkAtoms::h2, nsGkAtoms::h3,
      nsGkAtoms::h4, nsGkAtoms::h5, nsGkAtoms::h6);
}

// We use bitmasks to test containment of elements. Elements are marked to be
// in certain groups by setting the mGroup member of the nsElementInfo struct
// to the corresponding GROUP_ values (OR'ed together). Similarly, elements are
// marked to allow containment of certain groups by setting the
// mCanContainGroups member of the nsElementInfo struct to the corresponding
// GROUP_ values (OR'ed together).
// Testing containment then simply consists of checking whether the
// mCanContainGroups bitmask of an element and the mGroup bitmask of a
// potential child overlap.

#define GROUP_NONE 0

// body, head, html
#define GROUP_TOPLEVEL (1 << 1)

// base, link, meta, script, style, title
#define GROUP_HEAD_CONTENT (1 << 2)

// b, big, i, s, small, strike, tt, u
#define GROUP_FONTSTYLE (1 << 3)

// abbr, acronym, cite, code, datalist, del, dfn, em, ins, kbd, mark, rb, rp
// rt, rtc, ruby, samp, strong, var
#define GROUP_PHRASE (1 << 4)

// a, applet, basefont, bdi, bdo, br, font, iframe, img, map, meter, object,
// output, picture, progress, q, script, span, sub, sup
#define GROUP_SPECIAL (1 << 5)

// button, form, input, label, select, textarea
#define GROUP_FORMCONTROL (1 << 6)

// address, applet, article, aside, blockquote, button, center, del, details,
// dialog, dir, div, dl, fieldset, figure, footer, form, h1, h2, h3, h4, h5,
// h6, header, hgroup, hr, iframe, ins, main, map, menu, nav, noframes,
// noscript, object, ol, p, pre, table, section, summary, ul
#define GROUP_BLOCK (1 << 7)

// frame, frameset
#define GROUP_FRAME (1 << 8)

// col, tbody
#define GROUP_TABLE_CONTENT (1 << 9)

// tr
#define GROUP_TBODY_CONTENT (1 << 10)

// td, th
#define GROUP_TR_CONTENT (1 << 11)

// col
#define GROUP_COLGROUP_CONTENT (1 << 12)

// param
#define GROUP_OBJECT_CONTENT (1 << 13)

// li
#define GROUP_LI (1 << 14)

// area
#define GROUP_MAP_CONTENT (1 << 15)

// optgroup, option
#define GROUP_SELECT_CONTENT (1 << 16)

// option
#define GROUP_OPTIONS (1 << 17)

// dd, dt
#define GROUP_DL_CONTENT (1 << 18)

// p
#define GROUP_P (1 << 19)

// text, whitespace, newline, comment
#define GROUP_LEAF (1 << 20)

// XXX This is because the editor does sublists illegally.
// ol, ul
#define GROUP_OL_UL (1 << 21)

// h1, h2, h3, h4, h5, h6
#define GROUP_HEADING (1 << 22)

// figcaption
#define GROUP_FIGCAPTION (1 << 23)

// picture members (img, source)
#define GROUP_PICTURE_CONTENT (1 << 24)

#define GROUP_INLINE_ELEMENT                                            \
  (GROUP_FONTSTYLE | GROUP_PHRASE | GROUP_SPECIAL | GROUP_FORMCONTROL | \
   GROUP_LEAF)

#define GROUP_FLOW_ELEMENT (GROUP_INLINE_ELEMENT | GROUP_BLOCK)

struct ElementInfo final {
#ifdef DEBUG
  nsHTMLTag mTag;
#endif
  uint32_t mGroup;
  uint32_t mCanContainGroups;
  bool mIsContainer;
  bool mCanContainSelf;
};

#ifdef DEBUG
#  define ELEM(_tag, _isContainer, _canContainSelf, _group, _canContainGroups) \
    {                                                                          \
      eHTMLTag_##_tag, _group, _canContainGroups, _isContainer,                \
          _canContainSelf                                                      \
    }
#else
#  define ELEM(_tag, _isContainer, _canContainSelf, _group, _canContainGroups) \
    { _group, _canContainGroups, _isContainer, _canContainSelf }
#endif

static const ElementInfo kElements[eHTMLTag_userdefined] = {
    ELEM(a, true, false, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(abbr, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(acronym, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(address, true, true, GROUP_BLOCK, GROUP_INLINE_ELEMENT | GROUP_P),
    // While applet is no longer a valid tag, removing it here breaks the editor
    // (compiles, but causes many tests to fail in odd ways). This list is
    // tracked against the main HTML Tag list, so any changes will require more
    // than just removing entries.
    ELEM(applet, true, true, GROUP_SPECIAL | GROUP_BLOCK,
         GROUP_FLOW_ELEMENT | GROUP_OBJECT_CONTENT),
    ELEM(area, false, false, GROUP_MAP_CONTENT, GROUP_NONE),
    ELEM(article, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(aside, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(audio, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(b, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(base, false, false, GROUP_HEAD_CONTENT, GROUP_NONE),
    ELEM(basefont, false, false, GROUP_SPECIAL, GROUP_NONE),
    ELEM(bdi, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(bdo, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(bgsound, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(big, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(blockquote, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(body, true, true, GROUP_TOPLEVEL, GROUP_FLOW_ELEMENT),
    ELEM(br, false, false, GROUP_SPECIAL, GROUP_NONE),
    ELEM(button, true, true, GROUP_FORMCONTROL | GROUP_BLOCK,
         GROUP_FLOW_ELEMENT),
    ELEM(canvas, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(caption, true, true, GROUP_NONE, GROUP_INLINE_ELEMENT),
    ELEM(center, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(cite, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(code, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(col, false, false, GROUP_TABLE_CONTENT | GROUP_COLGROUP_CONTENT,
         GROUP_NONE),
    ELEM(colgroup, true, false, GROUP_NONE, GROUP_COLGROUP_CONTENT),
    ELEM(data, true, false, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(datalist, true, false, GROUP_PHRASE,
         GROUP_OPTIONS | GROUP_INLINE_ELEMENT),
    ELEM(dd, true, false, GROUP_DL_CONTENT, GROUP_FLOW_ELEMENT),
    ELEM(del, true, true, GROUP_PHRASE | GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(details, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(dfn, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(dialog, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(dir, true, false, GROUP_BLOCK, GROUP_LI),
    ELEM(div, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(dl, true, false, GROUP_BLOCK, GROUP_DL_CONTENT),
    ELEM(dt, true, true, GROUP_DL_CONTENT, GROUP_INLINE_ELEMENT),
    ELEM(em, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(embed, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(fieldset, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(figcaption, true, false, GROUP_FIGCAPTION, GROUP_FLOW_ELEMENT),
    ELEM(figure, true, true, GROUP_BLOCK,
         GROUP_FLOW_ELEMENT | GROUP_FIGCAPTION),
    ELEM(font, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(footer, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(form, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(frame, false, false, GROUP_FRAME, GROUP_NONE),
    ELEM(frameset, true, true, GROUP_FRAME, GROUP_FRAME),
    ELEM(h1, true, false, GROUP_BLOCK | GROUP_HEADING, GROUP_INLINE_ELEMENT),
    ELEM(h2, true, false, GROUP_BLOCK | GROUP_HEADING, GROUP_INLINE_ELEMENT),
    ELEM(h3, true, false, GROUP_BLOCK | GROUP_HEADING, GROUP_INLINE_ELEMENT),
    ELEM(h4, true, false, GROUP_BLOCK | GROUP_HEADING, GROUP_INLINE_ELEMENT),
    ELEM(h5, true, false, GROUP_BLOCK | GROUP_HEADING, GROUP_INLINE_ELEMENT),
    ELEM(h6, true, false, GROUP_BLOCK | GROUP_HEADING, GROUP_INLINE_ELEMENT),
    ELEM(head, true, false, GROUP_TOPLEVEL, GROUP_HEAD_CONTENT),
    ELEM(header, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(hgroup, true, false, GROUP_BLOCK, GROUP_HEADING),
    ELEM(hr, false, false, GROUP_BLOCK, GROUP_NONE),
    ELEM(html, true, false, GROUP_TOPLEVEL, GROUP_TOPLEVEL),
    ELEM(i, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(iframe, true, true, GROUP_SPECIAL | GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(image, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(img, false, false, GROUP_SPECIAL | GROUP_PICTURE_CONTENT, GROUP_NONE),
    ELEM(input, false, false, GROUP_FORMCONTROL, GROUP_NONE),
    ELEM(ins, true, true, GROUP_PHRASE | GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(kbd, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(keygen, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(label, true, false, GROUP_FORMCONTROL, GROUP_INLINE_ELEMENT),
    ELEM(legend, true, true, GROUP_NONE, GROUP_INLINE_ELEMENT),
    ELEM(li, true, false, GROUP_LI, GROUP_FLOW_ELEMENT),
    ELEM(link, false, false, GROUP_HEAD_CONTENT, GROUP_NONE),
    ELEM(listing, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(main, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(map, true, true, GROUP_SPECIAL, GROUP_BLOCK | GROUP_MAP_CONTENT),
    ELEM(mark, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(marquee, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(menu, true, true, GROUP_BLOCK, GROUP_LI | GROUP_FLOW_ELEMENT),
    ELEM(menuitem, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(meta, false, false, GROUP_HEAD_CONTENT, GROUP_NONE),
    ELEM(meter, true, false, GROUP_SPECIAL, GROUP_FLOW_ELEMENT),
    ELEM(multicol, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(nav, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(nobr, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(noembed, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(noframes, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(noscript, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(object, true, true, GROUP_SPECIAL | GROUP_BLOCK,
         GROUP_FLOW_ELEMENT | GROUP_OBJECT_CONTENT),
    // XXX Can contain self and ul because editor does sublists illegally.
    ELEM(ol, true, true, GROUP_BLOCK | GROUP_OL_UL, GROUP_LI | GROUP_OL_UL),
    ELEM(optgroup, true, false, GROUP_SELECT_CONTENT, GROUP_OPTIONS),
    ELEM(option, true, false, GROUP_SELECT_CONTENT | GROUP_OPTIONS, GROUP_LEAF),
    ELEM(output, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(p, true, false, GROUP_BLOCK | GROUP_P, GROUP_INLINE_ELEMENT),
    ELEM(param, false, false, GROUP_OBJECT_CONTENT, GROUP_NONE),
    ELEM(picture, true, false, GROUP_SPECIAL, GROUP_PICTURE_CONTENT),
    ELEM(plaintext, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(pre, true, true, GROUP_BLOCK, GROUP_INLINE_ELEMENT),
    ELEM(progress, true, false, GROUP_SPECIAL, GROUP_FLOW_ELEMENT),
    ELEM(q, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(rb, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(rp, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(rt, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(rtc, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(ruby, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(s, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(samp, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(script, true, false, GROUP_HEAD_CONTENT | GROUP_SPECIAL, GROUP_LEAF),
    ELEM(section, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(select, true, false, GROUP_FORMCONTROL, GROUP_SELECT_CONTENT),
    ELEM(small, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(slot, true, false, GROUP_NONE, GROUP_FLOW_ELEMENT),
    ELEM(source, false, false, GROUP_PICTURE_CONTENT, GROUP_NONE),
    ELEM(span, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(strike, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(strong, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(style, true, false, GROUP_HEAD_CONTENT, GROUP_LEAF),
    ELEM(sub, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(summary, true, true, GROUP_BLOCK, GROUP_FLOW_ELEMENT),
    ELEM(sup, true, true, GROUP_SPECIAL, GROUP_INLINE_ELEMENT),
    ELEM(table, true, false, GROUP_BLOCK, GROUP_TABLE_CONTENT),
    ELEM(tbody, true, false, GROUP_TABLE_CONTENT, GROUP_TBODY_CONTENT),
    ELEM(td, true, false, GROUP_TR_CONTENT, GROUP_FLOW_ELEMENT),
    ELEM(textarea, true, false, GROUP_FORMCONTROL, GROUP_LEAF),
    ELEM(tfoot, true, false, GROUP_NONE, GROUP_TBODY_CONTENT),
    ELEM(th, true, false, GROUP_TR_CONTENT, GROUP_FLOW_ELEMENT),
    ELEM(thead, true, false, GROUP_NONE, GROUP_TBODY_CONTENT),
    ELEM(template, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(time, true, false, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(title, true, false, GROUP_HEAD_CONTENT, GROUP_LEAF),
    ELEM(tr, true, false, GROUP_TBODY_CONTENT, GROUP_TR_CONTENT),
    ELEM(track, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(tt, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    ELEM(u, true, true, GROUP_FONTSTYLE, GROUP_INLINE_ELEMENT),
    // XXX Can contain self and ol because editor does sublists illegally.
    ELEM(ul, true, true, GROUP_BLOCK | GROUP_OL_UL, GROUP_LI | GROUP_OL_UL),
    ELEM(var, true, true, GROUP_PHRASE, GROUP_INLINE_ELEMENT),
    ELEM(video, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(wbr, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(xmp, false, false, GROUP_NONE, GROUP_NONE),

    // These aren't elements.
    ELEM(text, false, false, GROUP_LEAF, GROUP_NONE),
    ELEM(whitespace, false, false, GROUP_LEAF, GROUP_NONE),
    ELEM(newline, false, false, GROUP_LEAF, GROUP_NONE),
    ELEM(comment, false, false, GROUP_LEAF, GROUP_NONE),
    ELEM(entity, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(doctypeDecl, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(markupDecl, false, false, GROUP_NONE, GROUP_NONE),
    ELEM(instruction, false, false, GROUP_NONE, GROUP_NONE),

    ELEM(userdefined, true, false, GROUP_NONE, GROUP_FLOW_ELEMENT)};

bool HTMLEditUtils::CanContain(int32_t aParent, int32_t aChild) {
  NS_ASSERTION(aParent > eHTMLTag_unknown && aParent <= eHTMLTag_userdefined,
               "aParent out of range!");
  NS_ASSERTION(aChild > eHTMLTag_unknown && aChild <= eHTMLTag_userdefined,
               "aChild out of range!");

#ifdef DEBUG
  static bool checked = false;
  if (!checked) {
    checked = true;
    int32_t i;
    for (i = 1; i <= eHTMLTag_userdefined; ++i) {
      NS_ASSERTION(kElements[i - 1].mTag == i,
                   "You need to update kElements (missing tags).");
    }
  }
#endif

  // Special-case button.
  if (aParent == eHTMLTag_button) {
    static const nsHTMLTag kButtonExcludeKids[] = {
        eHTMLTag_a,     eHTMLTag_fieldset, eHTMLTag_form,    eHTMLTag_iframe,
        eHTMLTag_input, eHTMLTag_select,   eHTMLTag_textarea};

    uint32_t j;
    for (j = 0; j < ArrayLength(kButtonExcludeKids); ++j) {
      if (kButtonExcludeKids[j] == aChild) {
        return false;
      }
    }
  }

  // Deprecated elements.
  if (aChild == eHTMLTag_bgsound) {
    return false;
  }

  // Bug #67007, dont strip userdefined tags.
  if (aChild == eHTMLTag_userdefined) {
    return true;
  }

  const ElementInfo& parent = kElements[aParent - 1];
  if (aParent == aChild) {
    return parent.mCanContainSelf;
  }

  const ElementInfo& child = kElements[aChild - 1];
  return (parent.mCanContainGroups & child.mGroup) != 0;
}

bool HTMLEditUtils::IsContainer(int32_t aTag) {
  NS_ASSERTION(aTag > eHTMLTag_unknown && aTag <= eHTMLTag_userdefined,
               "aTag out of range!");

  return kElements[aTag - 1].mIsContainer;
}

bool HTMLEditUtils::IsNonListSingleLineContainer(nsINode& aNode) {
  return aNode.IsAnyOfHTMLElements(
      nsGkAtoms::address, nsGkAtoms::div, nsGkAtoms::h1, nsGkAtoms::h2,
      nsGkAtoms::h3, nsGkAtoms::h4, nsGkAtoms::h5, nsGkAtoms::h6,
      nsGkAtoms::listing, nsGkAtoms::p, nsGkAtoms::pre, nsGkAtoms::xmp);
}

bool HTMLEditUtils::IsSingleLineContainer(nsINode& aNode) {
  return IsNonListSingleLineContainer(aNode) ||
         aNode.IsAnyOfHTMLElements(nsGkAtoms::li, nsGkAtoms::dt, nsGkAtoms::dd);
}

EditAction HTMLEditUtils::GetEditActionForInsert(const nsAtom& aTagName) {
  // This method may be in a hot path.  So, return only necessary
  // EditAction::eInsert*Element.
  if (&aTagName == nsGkAtoms::ul) {
    // For InputEvent.inputType, "insertUnorderedList".
    return EditAction::eInsertUnorderedListElement;
  }
  if (&aTagName == nsGkAtoms::ol) {
    // For InputEvent.inputType, "insertOrderedList".
    return EditAction::eInsertOrderedListElement;
  }
  if (&aTagName == nsGkAtoms::hr) {
    // For InputEvent.inputType, "insertHorizontalRule".
    return EditAction::eInsertHorizontalRuleElement;
  }
  return EditAction::eInsertNode;
}

EditAction HTMLEditUtils::GetEditActionForRemoveList(const nsAtom& aTagName) {
  // This method may be in a hot path.  So, return only necessary
  // EditAction::eRemove*Element.
  if (&aTagName == nsGkAtoms::ul) {
    // For InputEvent.inputType, "insertUnorderedList".
    return EditAction::eRemoveUnorderedListElement;
  }
  if (&aTagName == nsGkAtoms::ol) {
    // For InputEvent.inputType, "insertOrderedList".
    return EditAction::eRemoveOrderedListElement;
  }
  return EditAction::eRemoveListElement;
}

EditAction HTMLEditUtils::GetEditActionForInsert(const Element& aElement) {
  return GetEditActionForInsert(*aElement.NodeInfo()->NameAtom());
}

EditAction HTMLEditUtils::GetEditActionForFormatText(const nsAtom& aProperty,
                                                     const nsAtom* aAttribute,
                                                     bool aToSetStyle) {
  // This method may be in a hot path.  So, return only necessary
  // EditAction::eSet*Property or EditAction::eRemove*Property.
  if (&aProperty == nsGkAtoms::b) {
    return aToSetStyle ? EditAction::eSetFontWeightProperty
                       : EditAction::eRemoveFontWeightProperty;
  }
  if (&aProperty == nsGkAtoms::i) {
    return aToSetStyle ? EditAction::eSetTextStyleProperty
                       : EditAction::eRemoveTextStyleProperty;
  }
  if (&aProperty == nsGkAtoms::u) {
    return aToSetStyle ? EditAction::eSetTextDecorationPropertyUnderline
                       : EditAction::eRemoveTextDecorationPropertyUnderline;
  }
  if (&aProperty == nsGkAtoms::strike) {
    return aToSetStyle ? EditAction::eSetTextDecorationPropertyLineThrough
                       : EditAction::eRemoveTextDecorationPropertyLineThrough;
  }
  if (&aProperty == nsGkAtoms::sup) {
    return aToSetStyle ? EditAction::eSetVerticalAlignPropertySuper
                       : EditAction::eRemoveVerticalAlignPropertySuper;
  }
  if (&aProperty == nsGkAtoms::sub) {
    return aToSetStyle ? EditAction::eSetVerticalAlignPropertySub
                       : EditAction::eRemoveVerticalAlignPropertySub;
  }
  if (&aProperty == nsGkAtoms::font) {
    if (aAttribute == nsGkAtoms::face) {
      return aToSetStyle ? EditAction::eSetFontFamilyProperty
                         : EditAction::eRemoveFontFamilyProperty;
    }
    if (aAttribute == nsGkAtoms::color) {
      return aToSetStyle ? EditAction::eSetColorProperty
                         : EditAction::eRemoveColorProperty;
    }
    if (aAttribute == nsGkAtoms::bgcolor) {
      return aToSetStyle ? EditAction::eSetBackgroundColorPropertyInline
                         : EditAction::eRemoveBackgroundColorPropertyInline;
    }
  }
  return aToSetStyle ? EditAction::eSetInlineStyleProperty
                     : EditAction::eRemoveInlineStyleProperty;
}

EditAction HTMLEditUtils::GetEditActionForAlignment(
    const nsAString& aAlignType) {
  // This method may be in a hot path.  So, return only necessary
  // EditAction::eAlign*.
  if (aAlignType.EqualsLiteral("left")) {
    return EditAction::eAlignLeft;
  }
  if (aAlignType.EqualsLiteral("right")) {
    return EditAction::eAlignRight;
  }
  if (aAlignType.EqualsLiteral("center")) {
    return EditAction::eAlignCenter;
  }
  if (aAlignType.EqualsLiteral("justify")) {
    return EditAction::eJustify;
  }
  return EditAction::eSetAlignment;
}

}  // namespace mozilla