chromium/src/third_party/blink/renderer/core/dom/first_letter_pseudo_element.cc - manifest_repos/chromium_src - Git at Google

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc.
  * All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 #include "third_party/blink/renderer/core/dom/first_letter_pseudo_element.h"

 #include "third_party/blink/renderer/core/css/style_change_reason.h"
 #include "third_party/blink/renderer/core/dom/element.h"
 #include "third_party/blink/renderer/core/dom/node_computed_style.h"
 #include "third_party/blink/renderer/core/layout/generated_children.h"
 #include "third_party/blink/renderer/core/layout/layout_object.h"
 #include "third_party/blink/renderer/core/layout/layout_object_inlines.h"
 #include "third_party/blink/renderer/core/layout/layout_text.h"
 #include "third_party/blink/renderer/core/layout/layout_text_fragment.h"
 #include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_item.h"
 #include "third_party/blink/renderer/platform/text/text_break_iterator.h"
 #include "third_party/blink/renderer/platform/wtf/text/unicode.h"
 #include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"

 namespace blink {

 // CSS 2.1 http://www.w3.org/TR/CSS21/selector.html#first-letter "Punctuation
 // (i.e, characters defined in Unicode [UNICODE] in the "open" (Ps), "close"
 // (Pe), "initial" (Pi). "final" (Pf) and "other" (Po) punctuation classes),
 // that precedes or follows the first letter should be included"
 static inline bool IsPunctuationForFirstLetter(UChar32 c) {
   WTF::unicode::CharCategory char_category = WTF::unicode::Category(c);
   return char_category == WTF::unicode::kPunctuation_Open ||
          char_category == WTF::unicode::kPunctuation_Close ||
          char_category == WTF::unicode::kPunctuation_InitialQuote ||
          char_category == WTF::unicode::kPunctuation_FinalQuote ||
          char_category == WTF::unicode::kPunctuation_Other;
 }

 static inline bool IsSpaceForFirstLetter(UChar c) {
   return IsSpaceOrNewline(c) || c == WTF::unicode::kNoBreakSpaceCharacter;
 }

 unsigned FirstLetterPseudoElement::FirstLetterLength(const String& text) {
   unsigned length = 0;
   unsigned text_length = text.length();

   if (text_length == 0)
     return length;

   // Account for leading spaces first.
   while (length < text_length && IsSpaceForFirstLetter(text[length]))
     length++;
   // Now account for leading punctuation.
   while (length < text_length &&
          IsPunctuationForFirstLetter(text.CharacterStartingAt(length)))
     length += LengthOfGraphemeCluster(text, length);

   // Bail if we didn't find a letter before the end of the text or before a
   // space.
   if (IsSpaceForFirstLetter(text[length]) || length == text_length)
     return 0;

   // Account the next character for first letter.
   length += LengthOfGraphemeCluster(text, length);

   // Keep looking for allowed punctuation for the :first-letter.
   unsigned num_code_units = 0;
   for (; length < text_length; length += num_code_units) {
     UChar32 c = text.CharacterStartingAt(length);
     if (!IsPunctuationForFirstLetter(c))
       break;
     num_code_units = LengthOfGraphemeCluster(text, length);
   }
   return length;
 }

 // Once we see any of these layoutObjects we can stop looking for first-letter
 // as they signal the end of the first line of text.
 static bool IsInvalidFirstLetterLayoutObject(const LayoutObject* obj) {
   return (obj->IsBR() || (obj->IsText() && To<LayoutText>(obj)->IsWordBreak()));
 }

 LayoutText* FirstLetterPseudoElement::FirstLetterTextLayoutObject(
     const Element& element) {
   LayoutObject* parent_layout_object = nullptr;

   // If we are looking at a first letter element then we need to find the
   // first letter text LayoutObject from the parent node, and not ourselves.
   if (element.IsFirstLetterPseudoElement()) {
     parent_layout_object =
         element.ParentOrShadowHostElement()->GetLayoutObject();
   } else {
     parent_layout_object = element.GetLayoutObject();
   }

   if (!parent_layout_object ||
       !parent_layout_object->Style()->HasPseudoElementStyle(
           kPseudoIdFirstLetter) ||
       !CanHaveGeneratedChildren(*parent_layout_object) ||
       !parent_layout_object->BehavesLikeBlockContainer())
     return nullptr;

   // Drill down into our children and look for our first text child.
   LayoutObject* first_letter_text_layout_object =
       parent_layout_object->SlowFirstChild();
   while (first_letter_text_layout_object) {
     // This can be called when the first letter layoutObject is already in the
     // tree. We do not want to consider that layoutObject for our text
     // layoutObject so we go to the sibling (which is the LayoutTextFragment for
     // the remaining text).
     if (first_letter_text_layout_object->Style() &&
         first_letter_text_layout_object->Style()->StyleType() ==
             kPseudoIdFirstLetter) {
       first_letter_text_layout_object =
           first_letter_text_layout_object->NextSibling();
     } else if (first_letter_text_layout_object->IsText()) {
       // FIXME: If there is leading punctuation in a different LayoutText than
       // the first letter, we'll not apply the correct style to it.
       scoped_refptr<StringImpl> str =
           To<LayoutText>(first_letter_text_layout_object)->IsTextFragment()
               ? To<LayoutTextFragment>(first_letter_text_layout_object)
                     ->CompleteText()
               : To<LayoutText>(first_letter_text_layout_object)->OriginalText();
       if (FirstLetterLength(str.get()) ||
           IsInvalidFirstLetterLayoutObject(first_letter_text_layout_object))
         break;
       first_letter_text_layout_object =
           first_letter_text_layout_object->NextSibling();
     } else if (first_letter_text_layout_object->IsListMarkerIncludingAll()) {
       // The list item marker may have out-of-flow siblings inside an anonymous
       // block. Skip them to make sure we leave the anonymous block before
       // continuing looking for the first letter text.
       do {
         first_letter_text_layout_object =
             first_letter_text_layout_object->NextInPreOrderAfterChildren(
                 parent_layout_object);
       } while (
           first_letter_text_layout_object &&
           first_letter_text_layout_object->IsFloatingOrOutOfFlowPositioned());
     } else if (first_letter_text_layout_object
                    ->IsFloatingOrOutOfFlowPositioned()) {
       if (first_letter_text_layout_object->Style()->StyleType() ==
           kPseudoIdFirstLetter) {
         first_letter_text_layout_object =
             first_letter_text_layout_object->SlowFirstChild();
         break;
       }
       first_letter_text_layout_object =
           first_letter_text_layout_object->NextSibling();
     } else if (first_letter_text_layout_object->IsAtomicInlineLevel() ||
                first_letter_text_layout_object->IsButtonIncludingNG() ||
                IsMenuList(first_letter_text_layout_object)) {
       return nullptr;
     } else if (first_letter_text_layout_object
                    ->IsFlexibleBoxIncludingDeprecatedAndNG() ||
                first_letter_text_layout_object->IsLayoutGridIncludingNG()) {
       first_letter_text_layout_object =
           first_letter_text_layout_object->NextSibling();
     } else if (!first_letter_text_layout_object->IsInline() &&
                first_letter_text_layout_object->Style()->HasPseudoElementStyle(
                    kPseudoIdFirstLetter) &&
                CanHaveGeneratedChildren(*first_letter_text_layout_object)) {
       // There is a layoutObject further down the tree which has
       // PseudoIdFirstLetter set. When that node is attached we will handle
       // setting up the first letter then.
       return nullptr;
     } else if (first_letter_text_layout_object->IsInline() &&
                !first_letter_text_layout_object->SlowFirstChild()) {
       if (LayoutObject* next_sibling =
               first_letter_text_layout_object->NextSibling()) {
         first_letter_text_layout_object = next_sibling;
         continue;
       }
       LayoutObject* parent = first_letter_text_layout_object->Parent();
       if (parent && parent != parent_layout_object) {
         first_letter_text_layout_object = parent->NextSibling();
         continue;
       }
       return nullptr;
     } else {
       first_letter_text_layout_object =
           first_letter_text_layout_object->SlowFirstChild();
     }
   }

   // No first letter text to display, we're done.
   // FIXME: This list of disallowed LayoutText subclasses is fragile.
   // crbug.com/422336.
   // Should counter be on this list? What about LayoutTextFragment?
   if (!first_letter_text_layout_object ||
       !first_letter_text_layout_object->IsText() ||
       IsInvalidFirstLetterLayoutObject(first_letter_text_layout_object))
     return nullptr;

   return To<LayoutText>(first_letter_text_layout_object);
 }

 FirstLetterPseudoElement::FirstLetterPseudoElement(Element* parent)
     : PseudoElement(parent, kPseudoIdFirstLetter),
       remaining_text_layout_object_(nullptr) {}

 FirstLetterPseudoElement::~FirstLetterPseudoElement() {
   DCHECK(!remaining_text_layout_object_);
 }

 void FirstLetterPseudoElement::UpdateTextFragments() {
   String old_text(remaining_text_layout_object_->CompleteText());
   DCHECK(old_text.Impl());

   unsigned length = FirstLetterPseudoElement::FirstLetterLength(old_text);
   remaining_text_layout_object_->SetTextFragment(
       old_text.Impl()->Substring(length, old_text.length()), length,
       old_text.length() - length);
   remaining_text_layout_object_->DirtyLineBoxes();

   for (auto* child = GetLayoutObject()->SlowFirstChild(); child;
        child = child->NextSibling()) {
     if (!child->IsText() || !To<LayoutText>(child)->IsTextFragment())
       continue;
     auto* child_fragment = To<LayoutTextFragment>(child);
     if (child_fragment->GetFirstLetterPseudoElement() != this)
       continue;

     child_fragment->SetTextFragment(old_text.Impl()->Substring(0, length), 0,
                                     length);
     child_fragment->DirtyLineBoxes();

     // Make sure the first-letter layoutObject is set to require a layout as it
     // needs to re-create the line boxes. The remaining text layoutObject
     // will be marked by the LayoutText::setText.
     child_fragment->SetNeedsLayoutAndIntrinsicWidthsRecalc(
         layout_invalidation_reason::kTextChanged);
     break;
   }
 }

 void FirstLetterPseudoElement::ClearRemainingTextLayoutObject() {
   DCHECK(remaining_text_layout_object_);
   remaining_text_layout_object_ = nullptr;

   if (GetDocument().InStyleRecalc()) {
     // UpdateFirstLetterPseudoElement will handle remaining_text_layout_object_
     // changes during style recalc and layout tree rebuild.
     return;
   }

   // When we remove nodes from the tree, we do not mark ancestry for
   // ChildNeedsStyleRecalc(). When removing the text node which contains the
   // first letter, we need to UpdateFirstLetter to render the new first letter
   // or remove the ::first-letter pseudo if there is no text left. Do that as
   // part of a style recalc for this ::first-letter.
   SetNeedsStyleRecalc(
       kLocalStyleChange,
       StyleChangeReasonForTracing::Create(style_change_reason::kPseudoClass));
 }

 void FirstLetterPseudoElement::AttachLayoutTree(AttachContext& context) {
   LayoutText* first_letter_text =
       FirstLetterPseudoElement::FirstLetterTextLayoutObject(*this);
   // The FirstLetterPseudoElement should have been removed in
   // Element::UpdateFirstLetterPseudoElement(). However if there existed a first
   // letter before updating it, the layout tree will be different after
   // DetachLayoutTree() called right before this method.
   // If there is a bug in FirstLetterTextLayoutObject(), we might end up with
   // null here. DCHECKing here, but handling the null pointer below to avoid
   // crashes.
   DCHECK(first_letter_text);

   AttachContext first_letter_context(context);
   first_letter_context.next_sibling = first_letter_text;
   first_letter_context.next_sibling_valid = true;
   if (first_letter_text) {
     first_letter_context.parent = first_letter_text->Parent();
     if (first_letter_context.parent->ForceLegacyLayout())
       first_letter_context.force_legacy_layout = true;
   }
   PseudoElement::AttachLayoutTree(first_letter_context);
   if (first_letter_text)
     AttachFirstLetterTextLayoutObjects(first_letter_text);
 }

 void FirstLetterPseudoElement::DetachLayoutTree(bool performing_reattach) {
   if (remaining_text_layout_object_) {
     if (remaining_text_layout_object_->GetNode() && GetDocument().IsActive()) {
       auto* text_node = To<Text>(remaining_text_layout_object_->GetNode());
       remaining_text_layout_object_->SetTextFragment(
           text_node->DataImpl(), 0, text_node->DataImpl()->length());
     }
     remaining_text_layout_object_->SetFirstLetterPseudoElement(nullptr);
     remaining_text_layout_object_->SetIsRemainingTextLayoutObject(false);
   }
   remaining_text_layout_object_ = nullptr;

   PseudoElement::DetachLayoutTree(performing_reattach);
 }

 scoped_refptr<ComputedStyle>
 FirstLetterPseudoElement::CustomStyleForLayoutObject(
     const StyleRecalcContext& style_recalc_context) {
   LayoutObject* first_letter_text =
       FirstLetterPseudoElement::FirstLetterTextLayoutObject(*this);
   if (!first_letter_text)
     return nullptr;
   DCHECK(first_letter_text->Parent());
   return ParentOrShadowHostElement()->StyleForPseudoElement(
       style_recalc_context, PseudoElementStyleRequest(GetPseudoId()),
       first_letter_text->Parent()->FirstLineStyle());
 }

 void FirstLetterPseudoElement::AttachFirstLetterTextLayoutObjects(LayoutText* first_letter_text) {
   DCHECK(first_letter_text);

   // The original string is going to be either a generated content string or a
   // DOM node's string. We want the original string before it got transformed in
   // case first-letter has no text-transform or a different text-transform
   // applied to it.
   String old_text =
       first_letter_text->IsTextFragment()
           ? To<LayoutTextFragment>(first_letter_text)->CompleteText()
           : first_letter_text->OriginalText();
   DCHECK(old_text.Impl());

   // FIXME: This would already have been calculated in firstLetterLayoutObject.
   // Can we pass the length through?
   unsigned length = FirstLetterPseudoElement::FirstLetterLength(old_text);
   unsigned remaining_length = old_text.length() - length;

   // Construct a text fragment for the text after the first letter.
   // This text fragment might be empty.
   LayoutTextFragment* remaining_text;

   LegacyLayout legacy_layout = first_letter_text->ForceLegacyLayout()
                                    ? LegacyLayout::kForce
                                    : LegacyLayout::kAuto;

   if (first_letter_text->GetNode()) {
     remaining_text = LayoutTextFragment::Create(
         first_letter_text->GetNode(), old_text.Impl(), length, remaining_length,
         legacy_layout);
   } else {
     remaining_text = LayoutTextFragment::CreateAnonymous(
         *this, old_text.Impl(), length, remaining_length, legacy_layout);
   }

   remaining_text->SetFirstLetterPseudoElement(this);
   remaining_text->SetIsRemainingTextLayoutObject(true);
   remaining_text->SetStyle(first_letter_text->Style());

   if (remaining_text->GetNode())
     remaining_text->GetNode()->SetLayoutObject(remaining_text);

   remaining_text_layout_object_ = remaining_text;

   LayoutObject* next_sibling = GetLayoutObject()->NextSibling();
   GetLayoutObject()->Parent()->AddChild(remaining_text, next_sibling);

   // Construct text fragment for the first letter.
   const ComputedStyle* const letter_style = GetComputedStyle();
   LayoutTextFragment* letter = LayoutTextFragment::CreateAnonymous(
       *this, old_text.Impl(), 0, length, legacy_layout);
   letter->SetFirstLetterPseudoElement(this);
   letter->SetStyle(letter_style);
   GetLayoutObject()->AddChild(letter);

   first_letter_text->Destroy();
 }

 Node* FirstLetterPseudoElement::InnerNodeForHitTesting() const {
   // When we hit a first letter during hit testing, hover state and events
   // should be triggered on the parent of the real text node where the first
   // letter is taken from. The first letter may not come from a real node - for
   // quotes and generated text in ::before/::after. In that case walk up the
   // layout tree to find the closest ancestor which is not anonymous. Note that
   // display:contents will not be skipped since we generate anonymous
   // LayoutInline boxes for ::before/::after with display:contents.
   DCHECK(remaining_text_layout_object_);
   LayoutObject* layout_object = remaining_text_layout_object_;
   while (layout_object->IsAnonymous()) {
     layout_object = layout_object->Parent();
     DCHECK(layout_object);
   }
   Node* node = layout_object->GetNode();
   DCHECK(node);
   if (layout_object == remaining_text_layout_object_) {
     // The text containing the first-letter is a real node, return its flat tree
     // parent. If we used the layout tree parent, we would have incorrectly
     // skipped display:contents ancestors.
     return FlatTreeTraversal::Parent(*node);
   }
   if (node->IsPseudoElement()) {
     // ::first-letter in generated content for ::before/::after. Use pseudo
     // element parent.
     return node->ParentOrShadowHostNode();
   }
   return node;
 }

 }  // namespace blink
	/*
	* Copyright (C) 1999 Lars Knoll (knoll@kde.org)
	* (C) 1999 Antti Koivisto (koivisto@kde.org)
	* (C) 2007 David Smith (catfish.man@gmail.com)
	* Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc.
	* All rights reserved.
	* Copyright (C) Research In Motion Limited 2010. All rights reserved.
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public License
	* along with this library; see the file COPYING.LIB. If not, write to
	* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	#include "third_party/blink/renderer/core/dom/first_letter_pseudo_element.h"

	#include "third_party/blink/renderer/core/css/style_change_reason.h"
	#include "third_party/blink/renderer/core/dom/element.h"
	#include "third_party/blink/renderer/core/dom/node_computed_style.h"
	#include "third_party/blink/renderer/core/layout/generated_children.h"
	#include "third_party/blink/renderer/core/layout/layout_object.h"
	#include "third_party/blink/renderer/core/layout/layout_object_inlines.h"
	#include "third_party/blink/renderer/core/layout/layout_text.h"
	#include "third_party/blink/renderer/core/layout/layout_text_fragment.h"
	#include "third_party/blink/renderer/core/layout/ng/list/layout_ng_list_item.h"
	#include "third_party/blink/renderer/platform/text/text_break_iterator.h"
	#include "third_party/blink/renderer/platform/wtf/text/unicode.h"
	#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"

	namespace blink {

	// CSS 2.1 http://www.w3.org/TR/CSS21/selector.html#first-letter "Punctuation
	// (i.e, characters defined in Unicode [UNICODE] in the "open" (Ps), "close"
	// (Pe), "initial" (Pi). "final" (Pf) and "other" (Po) punctuation classes),
	// that precedes or follows the first letter should be included"
	static inline bool IsPunctuationForFirstLetter(UChar32 c) {
	WTF::unicode::CharCategory char_category = WTF::unicode::Category(c);
	return char_category == WTF::unicode::kPunctuation_Open \|\|
	char_category == WTF::unicode::kPunctuation_Close \|\|
	char_category == WTF::unicode::kPunctuation_InitialQuote \|\|
	char_category == WTF::unicode::kPunctuation_FinalQuote \|\|
	char_category == WTF::unicode::kPunctuation_Other;
	}

	static inline bool IsSpaceForFirstLetter(UChar c) {
	return IsSpaceOrNewline(c) \|\| c == WTF::unicode::kNoBreakSpaceCharacter;
	}

	unsigned FirstLetterPseudoElement::FirstLetterLength(const String& text) {
	unsigned length = 0;
	unsigned text_length = text.length();

	if (text_length == 0)
	return length;

	// Account for leading spaces first.
	while (length < text_length && IsSpaceForFirstLetter(text[length]))
	length++;
	// Now account for leading punctuation.
	while (length < text_length &&
	IsPunctuationForFirstLetter(text.CharacterStartingAt(length)))
	length += LengthOfGraphemeCluster(text, length);

	// Bail if we didn't find a letter before the end of the text or before a
	// space.
	if (IsSpaceForFirstLetter(text[length]) \|\| length == text_length)
	return 0;

	// Account the next character for first letter.
	length += LengthOfGraphemeCluster(text, length);

	// Keep looking for allowed punctuation for the :first-letter.
	unsigned num_code_units = 0;
	for (; length < text_length; length += num_code_units) {
	UChar32 c = text.CharacterStartingAt(length);
	if (!IsPunctuationForFirstLetter(c))
	break;
	num_code_units = LengthOfGraphemeCluster(text, length);
	}
	return length;
	}

	// Once we see any of these layoutObjects we can stop looking for first-letter
	// as they signal the end of the first line of text.
	static bool IsInvalidFirstLetterLayoutObject(const LayoutObject* obj) {
	return (obj->IsBR() \|\| (obj->IsText() && To<LayoutText>(obj)->IsWordBreak()));
	}

	LayoutText* FirstLetterPseudoElement::FirstLetterTextLayoutObject(
	const Element& element) {
	LayoutObject* parent_layout_object = nullptr;

	// If we are looking at a first letter element then we need to find the
	// first letter text LayoutObject from the parent node, and not ourselves.
	if (element.IsFirstLetterPseudoElement()) {
	parent_layout_object =
	element.ParentOrShadowHostElement()->GetLayoutObject();
	} else {
	parent_layout_object = element.GetLayoutObject();
	}

	if (!parent_layout_object \|\|
	!parent_layout_object->Style()->HasPseudoElementStyle(
	kPseudoIdFirstLetter) \|\|
	!CanHaveGeneratedChildren(*parent_layout_object) \|\|
	!parent_layout_object->BehavesLikeBlockContainer())
	return nullptr;

	// Drill down into our children and look for our first text child.
	LayoutObject* first_letter_text_layout_object =
	parent_layout_object->SlowFirstChild();
	while (first_letter_text_layout_object) {
	// This can be called when the first letter layoutObject is already in the
	// tree. We do not want to consider that layoutObject for our text
	// layoutObject so we go to the sibling (which is the LayoutTextFragment for
	// the remaining text).
	if (first_letter_text_layout_object->Style() &&
	first_letter_text_layout_object->Style()->StyleType() ==
	kPseudoIdFirstLetter) {
	first_letter_text_layout_object =
	first_letter_text_layout_object->NextSibling();
	} else if (first_letter_text_layout_object->IsText()) {
	// FIXME: If there is leading punctuation in a different LayoutText than
	// the first letter, we'll not apply the correct style to it.
	scoped_refptr<StringImpl> str =
	To<LayoutText>(first_letter_text_layout_object)->IsTextFragment()
	? To<LayoutTextFragment>(first_letter_text_layout_object)
	->CompleteText()
	: To<LayoutText>(first_letter_text_layout_object)->OriginalText();
	if (FirstLetterLength(str.get()) \|\|
	IsInvalidFirstLetterLayoutObject(first_letter_text_layout_object))
	break;
	first_letter_text_layout_object =
	first_letter_text_layout_object->NextSibling();
	} else if (first_letter_text_layout_object->IsListMarkerIncludingAll()) {
	// The list item marker may have out-of-flow siblings inside an anonymous
	// block. Skip them to make sure we leave the anonymous block before
	// continuing looking for the first letter text.
	do {
	first_letter_text_layout_object =
	first_letter_text_layout_object->NextInPreOrderAfterChildren(
	parent_layout_object);
	} while (
	first_letter_text_layout_object &&
	first_letter_text_layout_object->IsFloatingOrOutOfFlowPositioned());
	} else if (first_letter_text_layout_object
	->IsFloatingOrOutOfFlowPositioned()) {
	if (first_letter_text_layout_object->Style()->StyleType() ==
	kPseudoIdFirstLetter) {
	first_letter_text_layout_object =
	first_letter_text_layout_object->SlowFirstChild();
	break;
	}
	first_letter_text_layout_object =
	first_letter_text_layout_object->NextSibling();
	} else if (first_letter_text_layout_object->IsAtomicInlineLevel() \|\|
	first_letter_text_layout_object->IsButtonIncludingNG() \|\|
	IsMenuList(first_letter_text_layout_object)) {
	return nullptr;
	} else if (first_letter_text_layout_object
	->IsFlexibleBoxIncludingDeprecatedAndNG() \|\|
	first_letter_text_layout_object->IsLayoutGridIncludingNG()) {
	first_letter_text_layout_object =
	first_letter_text_layout_object->NextSibling();
	} else if (!first_letter_text_layout_object->IsInline() &&
	first_letter_text_layout_object->Style()->HasPseudoElementStyle(
	kPseudoIdFirstLetter) &&
	CanHaveGeneratedChildren(*first_letter_text_layout_object)) {
	// There is a layoutObject further down the tree which has
	// PseudoIdFirstLetter set. When that node is attached we will handle
	// setting up the first letter then.
	return nullptr;
	} else if (first_letter_text_layout_object->IsInline() &&
	!first_letter_text_layout_object->SlowFirstChild()) {
	if (LayoutObject* next_sibling =
	first_letter_text_layout_object->NextSibling()) {
	first_letter_text_layout_object = next_sibling;
	continue;
	}
	LayoutObject* parent = first_letter_text_layout_object->Parent();
	if (parent && parent != parent_layout_object) {
	first_letter_text_layout_object = parent->NextSibling();
	continue;
	}
	return nullptr;
	} else {
	first_letter_text_layout_object =
	first_letter_text_layout_object->SlowFirstChild();
	}
	}

	// No first letter text to display, we're done.
	// FIXME: This list of disallowed LayoutText subclasses is fragile.
	// crbug.com/422336.
	// Should counter be on this list? What about LayoutTextFragment?
	if (!first_letter_text_layout_object \|\|
	!first_letter_text_layout_object->IsText() \|\|
	IsInvalidFirstLetterLayoutObject(first_letter_text_layout_object))
	return nullptr;

	return To<LayoutText>(first_letter_text_layout_object);
	}

	FirstLetterPseudoElement::FirstLetterPseudoElement(Element* parent)
	: PseudoElement(parent, kPseudoIdFirstLetter),
	remaining_text_layout_object_(nullptr) {}

	FirstLetterPseudoElement::~FirstLetterPseudoElement() {
	DCHECK(!remaining_text_layout_object_);
	}

	void FirstLetterPseudoElement::UpdateTextFragments() {
	String old_text(remaining_text_layout_object_->CompleteText());
	DCHECK(old_text.Impl());

	unsigned length = FirstLetterPseudoElement::FirstLetterLength(old_text);
	remaining_text_layout_object_->SetTextFragment(
	old_text.Impl()->Substring(length, old_text.length()), length,
	old_text.length() - length);
	remaining_text_layout_object_->DirtyLineBoxes();

	for (auto* child = GetLayoutObject()->SlowFirstChild(); child;
	child = child->NextSibling()) {
	if (!child->IsText() \|\| !To<LayoutText>(child)->IsTextFragment())
	continue;
	auto* child_fragment = To<LayoutTextFragment>(child);
	if (child_fragment->GetFirstLetterPseudoElement() != this)
	continue;

	child_fragment->SetTextFragment(old_text.Impl()->Substring(0, length), 0,
	length);
	child_fragment->DirtyLineBoxes();

	// Make sure the first-letter layoutObject is set to require a layout as it
	// needs to re-create the line boxes. The remaining text layoutObject
	// will be marked by the LayoutText::setText.
	child_fragment->SetNeedsLayoutAndIntrinsicWidthsRecalc(
	layout_invalidation_reason::kTextChanged);
	break;
	}
	}

	void FirstLetterPseudoElement::ClearRemainingTextLayoutObject() {
	DCHECK(remaining_text_layout_object_);
	remaining_text_layout_object_ = nullptr;

	if (GetDocument().InStyleRecalc()) {
	// UpdateFirstLetterPseudoElement will handle remaining_text_layout_object_
	// changes during style recalc and layout tree rebuild.
	return;
	}

	// When we remove nodes from the tree, we do not mark ancestry for
	// ChildNeedsStyleRecalc(). When removing the text node which contains the
	// first letter, we need to UpdateFirstLetter to render the new first letter
	// or remove the ::first-letter pseudo if there is no text left. Do that as
	// part of a style recalc for this ::first-letter.
	SetNeedsStyleRecalc(
	kLocalStyleChange,
	StyleChangeReasonForTracing::Create(style_change_reason::kPseudoClass));
	}

	void FirstLetterPseudoElement::AttachLayoutTree(AttachContext& context) {
	LayoutText* first_letter_text =
	FirstLetterPseudoElement::FirstLetterTextLayoutObject(*this);
	// The FirstLetterPseudoElement should have been removed in
	// Element::UpdateFirstLetterPseudoElement(). However if there existed a first
	// letter before updating it, the layout tree will be different after
	// DetachLayoutTree() called right before this method.
	// If there is a bug in FirstLetterTextLayoutObject(), we might end up with
	// null here. DCHECKing here, but handling the null pointer below to avoid
	// crashes.
	DCHECK(first_letter_text);

	AttachContext first_letter_context(context);
	first_letter_context.next_sibling = first_letter_text;
	first_letter_context.next_sibling_valid = true;
	if (first_letter_text) {
	first_letter_context.parent = first_letter_text->Parent();
	if (first_letter_context.parent->ForceLegacyLayout())
	first_letter_context.force_legacy_layout = true;
	}
	PseudoElement::AttachLayoutTree(first_letter_context);
	if (first_letter_text)
	AttachFirstLetterTextLayoutObjects(first_letter_text);
	}

	void FirstLetterPseudoElement::DetachLayoutTree(bool performing_reattach) {
	if (remaining_text_layout_object_) {
	if (remaining_text_layout_object_->GetNode() && GetDocument().IsActive()) {
	auto* text_node = To<Text>(remaining_text_layout_object_->GetNode());
	remaining_text_layout_object_->SetTextFragment(
	text_node->DataImpl(), 0, text_node->DataImpl()->length());
	}
	remaining_text_layout_object_->SetFirstLetterPseudoElement(nullptr);
	remaining_text_layout_object_->SetIsRemainingTextLayoutObject(false);
	}
	remaining_text_layout_object_ = nullptr;

	PseudoElement::DetachLayoutTree(performing_reattach);
	}

	scoped_refptr<ComputedStyle>
	FirstLetterPseudoElement::CustomStyleForLayoutObject(
	const StyleRecalcContext& style_recalc_context) {
	LayoutObject* first_letter_text =
	FirstLetterPseudoElement::FirstLetterTextLayoutObject(*this);
	if (!first_letter_text)
	return nullptr;
	DCHECK(first_letter_text->Parent());
	return ParentOrShadowHostElement()->StyleForPseudoElement(
	style_recalc_context, PseudoElementStyleRequest(GetPseudoId()),
	first_letter_text->Parent()->FirstLineStyle());
	}

	void FirstLetterPseudoElement::AttachFirstLetterTextLayoutObjects(LayoutText* first_letter_text) {
	DCHECK(first_letter_text);

	// The original string is going to be either a generated content string or a
	// DOM node's string. We want the original string before it got transformed in
	// case first-letter has no text-transform or a different text-transform
	// applied to it.
	String old_text =
	first_letter_text->IsTextFragment()
	? To<LayoutTextFragment>(first_letter_text)->CompleteText()
	: first_letter_text->OriginalText();
	DCHECK(old_text.Impl());

	// FIXME: This would already have been calculated in firstLetterLayoutObject.
	// Can we pass the length through?
	unsigned length = FirstLetterPseudoElement::FirstLetterLength(old_text);
	unsigned remaining_length = old_text.length() - length;

	// Construct a text fragment for the text after the first letter.
	// This text fragment might be empty.
	LayoutTextFragment* remaining_text;

	LegacyLayout legacy_layout = first_letter_text->ForceLegacyLayout()
	? LegacyLayout::kForce
	: LegacyLayout::kAuto;

	if (first_letter_text->GetNode()) {
	remaining_text = LayoutTextFragment::Create(
	first_letter_text->GetNode(), old_text.Impl(), length, remaining_length,
	legacy_layout);
	} else {
	remaining_text = LayoutTextFragment::CreateAnonymous(
	*this, old_text.Impl(), length, remaining_length, legacy_layout);
	}

	remaining_text->SetFirstLetterPseudoElement(this);
	remaining_text->SetIsRemainingTextLayoutObject(true);
	remaining_text->SetStyle(first_letter_text->Style());

	if (remaining_text->GetNode())
	remaining_text->GetNode()->SetLayoutObject(remaining_text);

	remaining_text_layout_object_ = remaining_text;

	LayoutObject* next_sibling = GetLayoutObject()->NextSibling();
	GetLayoutObject()->Parent()->AddChild(remaining_text, next_sibling);

	// Construct text fragment for the first letter.
	const ComputedStyle* const letter_style = GetComputedStyle();
	LayoutTextFragment* letter = LayoutTextFragment::CreateAnonymous(
	*this, old_text.Impl(), 0, length, legacy_layout);
	letter->SetFirstLetterPseudoElement(this);
	letter->SetStyle(letter_style);
	GetLayoutObject()->AddChild(letter);

	first_letter_text->Destroy();
	}

	Node* FirstLetterPseudoElement::InnerNodeForHitTesting() const {
	// When we hit a first letter during hit testing, hover state and events
	// should be triggered on the parent of the real text node where the first
	// letter is taken from. The first letter may not come from a real node - for
	// quotes and generated text in ::before/::after. In that case walk up the
	// layout tree to find the closest ancestor which is not anonymous. Note that
	// display:contents will not be skipped since we generate anonymous
	// LayoutInline boxes for ::before/::after with display:contents.
	DCHECK(remaining_text_layout_object_);
	LayoutObject* layout_object = remaining_text_layout_object_;
	while (layout_object->IsAnonymous()) {
	layout_object = layout_object->Parent();
	DCHECK(layout_object);
	}
	Node* node = layout_object->GetNode();
	DCHECK(node);
	if (layout_object == remaining_text_layout_object_) {
	// The text containing the first-letter is a real node, return its flat tree
	// parent. If we used the layout tree parent, we would have incorrectly
	// skipped display:contents ancestors.
	return FlatTreeTraversal::Parent(*node);
	}
	if (node->IsPseudoElement()) {
	// ::first-letter in generated content for ::before/::after. Use pseudo
	// element parent.
	return node->ParentOrShadowHostNode();
	}
	return node;
	}

	} // namespace blink