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/PseudoElement.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_firstLetter(nullptr)
 {
 }
 
 RenderTextFragment::RenderTextFragment(Node* node, StringImpl* str)
     : RenderText(node, str)
     , m_start(0)
     , m_end(str ? str->length() : 0)
     , m_contentString(str)
-    , m_firstLetter(nullptr)
 {
 }
 
 RenderTextFragment::~RenderTextFragment()
 {
 }
 
-void RenderTextFragment::trace(Visitor* visitor)
+PassRefPtr<StringImpl> RenderTextFragment::completeText() const
 {
-    visitor->trace(m_firstLetter);
-    RenderText::trace(visitor);
-}
-
-RenderText* RenderTextFragment::firstRenderTextInFirstLetter() const
-{
-    for (RenderObject* current = m_firstLetter; current; current = current->nextInPreOrder(m_firstLetter)) {
-        if (current->isText())
-            return toRenderText(current);
-    }
-    return 0;
+    Text* e = associatedTextNode();

[esprehn, 2014/09/30 09:00:31]

text =, no single letter variables.

[dsinclair, 2014/09/30 21:46:34]

Done.

+    return e ? e->dataImpl() : contentString();
 }
 
 PassRefPtr<StringImpl> RenderTextFragment::originalText() const
 {
-    Node* e = node();
-    RefPtr<StringImpl> result = ((e && e->isTextNode()) ? toText(e)->dataImpl() : 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;
 
-        ASSERT(!m_contentString);
-        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()) {

[esprehn, 2014/09/30 09:00:31]

This feels sketchy, we can't keep an explicit RefPtr to the PseudoElement
instead?

[dsinclair, 2014/09/30 21:46:34]

I can do that, if it's preferred, I was more afraid of those pointers going
stale or the renderer having been removed already then just getting the sibling.

+        if (!previous->isPseudoElement() || !previous->node()->isFirstLetterPseudoElement())
+            return;
+
+        previous->node()->parentElement()->setNeedsStyleRecalc(SubtreeStyleChange);

[esprehn, 2014/09/30 09:00:31]

This is really bad, you're causing a subtree recalc every time the text value
changes.

ex.

<div>Text here
  ... thousands of divs ...
  <div></div>
  ...
</div>

if you reach in and touch the text node with "Text here" and change the value
you'll force a recalc style of thousands of divs.

[dsinclair, 2014/09/30 21:46:34]

Changed to LocalStyleChange. I had to add a second call to
previous->node()->setNeedsStyleRecalc() to force the first-letter pseudoElement
to also recalc style.

+
+        // FIXME:: Will this get cleaned up properly? OR am I leaking here?
+        previous->node()->detach();
     }
 }
 
 void RenderTextFragment::transformText()
 {
-    // Don't reset first-letter here because we are only transforming the truncated fragment.
     if (RefPtr<StringImpl> textToTransform = originalText())
         RenderText::setText(textToTransform.release(), true);
 }
 
 UChar RenderTextFragment::previousCharacter() const
 {
     if (start()) {
-        Node* e = node();
-        StringImpl* original = ((e && e->isTextNode()) ? toText(e)->dataImpl() : contentString());
+        StringImpl* original = completeText().get();
         if (original && start() <= original->length())
             return (*original)[start() - 1];
     }
 
     return RenderText::previousCharacter();
 }
 
-RenderBlock* RenderTextFragment::blockForAccompanyingFirstLetter() 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);
-    }
-    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())
+    if (!node())
         return;
 
-    if (isDescendantOf(toRenderTextFragment(nodeRenderer)->m_firstLetter))
-        result.setIsFirstLetter(true);
+    // FIXME(dsinclair): First letter?
 }
 
+// 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
+{
+    Node* e = node();

[esprehn, 2014/09/30 09:00:31]

node = this->node(); Not sure what e is, but no single letter vars.

[dsinclair, 2014/09/30 21:46:34]

Done.

+    if (!e)
+        return nullptr;
+
+    if (e->isFirstLetterPseudoElement()) {
+        Element* pseudo = toElement(e);
+        RenderObject* nextRenderer = pseudo->firstLetterTextRenderer();
+        if (!nextRenderer)
+            return nullptr;
+        e = nextRenderer->node();
+    }
+    return (e && e->isTextNode()) ? toText(e) : nullptr;

[esprehn, 2014/09/30 09:00:31]

This code seems overly cautious, how can firstLetterTextRenderer ever not be a
text node? node() is actually a Text* anyway (it must be).

[dsinclair, 2014/09/30 21:46:34]

I believe I broke that invariant (if it is invariant?). In
PseudoElement::attachFirstLetterTextRenderers(), when I create the
RenderTextFragment for the letter, I set the node to 'this'. There is wackyness
that happens if you create two renderers with the same node, if the node gets
removed from the tree bad things were happening. So, I changed the node for the
letter renderer to be the pseudoElement.

+}
+
+
 } // namespace blink