Convert first letter into a pseudo element.

Source/core/rendering/RenderTextFragment.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. 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 "config.h"
 #include "core/rendering/RenderTextFragment.h"
 
+#include "core/dom/FirstLetterPseudoElement.h"
+#include "core/dom/PseudoElement.h"
+#include "core/dom/StyleChangeReason.h"
 #include "core/dom/Text.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderBlock.h"
 
 namespace blink {
 
 RenderTextFragment::RenderTextFragment(Node* node, StringImpl* str, int startOffset, int length)
     : RenderText(node, str ? str->substring(startOffset, length) : PassRefPtr<StringImpl>(nullptr))
     , m_start(startOffset)
     , m_end(length)
+    , m_isRemainingTextRenderer(false)
     , m_contentString(str)
-    , m_firstLetter(nullptr)
+    , m_firstLetterPseudoElement(nullptr)
 {
 }
 
 RenderTextFragment::RenderTextFragment(Node* node, StringImpl* str)
     : RenderText(node, str)
     , m_start(0)
     , m_end(str ? str->length() : 0)
+    , m_isRemainingTextRenderer(false)
     , m_contentString(str)
-    , m_firstLetter(nullptr)
+    , m_firstLetterPseudoElement(nullptr)
 {
 }
 
 RenderTextFragment::~RenderTextFragment()
 {
+    ASSERT(!m_firstLetterPseudoElement);
+}
+
+void RenderTextFragment::destroy()
+{
+    if (m_isRemainingTextRenderer && m_firstLetterPseudoElement)
+        m_firstLetterPseudoElement->setRemainingTextRenderer(nullptr);
+    m_firstLetterPseudoElement = nullptr;
+    RenderText::destroy();
 }
 
 void RenderTextFragment::trace(Visitor* visitor)
 {
-    visitor->trace(m_firstLetter);
+    visitor->trace(m_firstLetterPseudoElement);
     RenderText::trace(visitor);
 }
 
-RenderText* RenderTextFragment::firstRenderTextInFirstLetter() const
+PassRefPtr<StringImpl> RenderTextFragment::completeText() const
 {
-    for (RenderObject* current = m_firstLetter; current; current = current->nextInPreOrder(m_firstLetter)) {
-        if (current->isText())
-            return toRenderText(current);
-    }
-    return 0;
+    Text* text = associatedTextNode();
+    return text ? text->dataImpl() : contentString();
 }
 
 void RenderTextFragment::setContentString(StringImpl* str)
 {
     m_contentString = str;
     setText(str);
 }
 
 PassRefPtr<StringImpl> RenderTextFragment::originalText() const
 {
-    RefPtr<StringImpl> result = RenderText::originalText();
-    if (!result)
-        result = m_contentString;
+    RefPtr<StringImpl> result = completeText();
     if (!result)
         return nullptr;
     return result->substring(start(), end());
 }
 
-void RenderTextFragment::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
-{
-    RenderText::styleDidChange(diff, oldStyle);
-
-    if (RenderBlock* block = blockForAccompanyingFirstLetter()) {
-        block->style()->removeCachedPseudoStyle(FIRST_LETTER);
-        block->updateFirstLetter();
-    }
-}
-
-void RenderTextFragment::willBeDestroyed()
-{
-    if (m_firstLetter)
-        m_firstLetter->destroy();
-    RenderText::willBeDestroyed();
-}
-
 void RenderTextFragment::setText(PassRefPtr<StringImpl> text, bool force)
 {
     RenderText::setText(text, force);
 
     m_start = 0;
     m_end = textLength();
-    if (m_firstLetter) {
-        // FIXME: We should not modify the structure of the render tree during
-        // layout. crbug.com/370458
-        DeprecatedDisableModifyRenderTreeStructureAsserts disabler;
 
-        m_firstLetter->destroy();
-        m_firstLetter = nullptr;
-        if (Node* t = node()) {
-            ASSERT(!t->renderer());
-            t->setRenderer(this);
-        }
+    // If we're the remaining text from a first letter then we have to tell the
+    // first letter pseudo element to reattach itself so it can re-calculate the
+    // correct first-letter settings.
+    if (RenderObject* previous = previousSibling()) {
+        if (!previous->isPseudoElement() || !previous->node()->isFirstLetterPseudoElement())
+            return;
+
+        // Tell the first letter container node, and the first-letter node
+        // that their style may have changed.
+        // e.g. fast/css/first-letter-detach.html
+        toFirstLetterPseudoElement(previous->node())->setNeedsUpdate();
     }
 }
 
 void RenderTextFragment::transformText()
 {
-    // Don't reset first-letter here because we are only transforming the truncated fragment.
+    // Note, we have to call RenderText::setText here because, if we use our
+    // version we will, potentially, screw up the first-letter settings where
+    // we only use portions of the string.
     if (RefPtr<StringImpl> textToTransform = originalText())
         RenderText::setText(textToTransform.release(), true);
 }
 
 UChar RenderTextFragment::previousCharacter() const
 {
     if (start()) {
-        RefPtr<StringImpl> original = RenderText::originalText();
-        if (!original)
-            original =  m_contentString;
+        StringImpl* original = completeText().get();
         if (original && start() <= original->length())
             return (*original)[start() - 1];
     }
 
     return RenderText::previousCharacter();
 }
 
-RenderBlock* RenderTextFragment::blockForAccompanyingFirstLetter() const
+// If this is the renderer for a first-letter pseudoNode then we have to look
+// at the node for the remaining text to find our content.
+Text* RenderTextFragment::associatedTextNode() const
 {
-    if (!m_firstLetter)
-        return 0;
-    for (RenderObject* block = m_firstLetter->parent(); block; block = block->parent()) {
-        if (block->style()->hasPseudoStyle(FIRST_LETTER) && block->canHaveChildren() && block->isRenderBlock())
-            return toRenderBlock(block);
+    Node* node = m_isRemainingTextRenderer ? this->node() : this->firstLetterPseudoElement();
+    if (!node)
+        return nullptr;
+
+    if (node->isFirstLetterPseudoElement()) {
+        FirstLetterPseudoElement* pseudo = toFirstLetterPseudoElement(node);
+        RenderObject* nextRenderer = FirstLetterPseudoElement::firstLetterTextRenderer(*pseudo);
+        if (!nextRenderer)
+            return nullptr;
+        node = nextRenderer->node();
     }
-    return 0;
-}
-
-void RenderTextFragment::updateHitTestResult(HitTestResult& result, const LayoutPoint& point)
-{
-    if (result.innerNode())
-        return;
-
-    RenderObject::updateHitTestResult(result, point);
-    if (m_firstLetter || !node())
-        return;
-    RenderObject* nodeRenderer = node()->renderer();
-    if (!nodeRenderer || !nodeRenderer->isText() || !toRenderText(nodeRenderer)->isTextFragment())
-        return;
-
-    if (isDescendantOf(toRenderTextFragment(nodeRenderer)->m_firstLetter))
-        result.setIsFirstLetter(true);
+    return (node && node->isTextNode()) ? toText(node) : nullptr;
 }
 
 } // namespace blink