From 0fcd743a640b2ec9f5cb7268833020ea40de4ec2 Mon Sep 17 00:00:00 2001
From: Elliott Sprehn <esprehn@chromium.org>
Date: Tue, 20 Jan 2015 14:26:54 -0800
Subject: [PATCH] Remove Element::textFromChildren().

Instead just use textContent() and teach HTMLStyleElement how to atomize
its children. I also added the optimization to Node::textContent so that
Text just returns its value instead of allocating a new buffer which
avoids malloc and copy when getting the textContent of text.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/864613002
---
 engine/core/dom/Element.cpp           | 40 ---------------------------
 engine/core/dom/Element.h             |  2 --
 engine/core/dom/Node.cpp              |  2 ++
 engine/core/html/HTMLStyleElement.cpp |  6 ++--
 4 files changed, 6 insertions(+), 44 deletions(-)

diff --git a/engine/core/dom/Element.cpp b/engine/core/dom/Element.cpp
index cd282835c46..2a9d24f901e 100644
--- a/engine/core/dom/Element.cpp
+++ b/engine/core/dom/Element.cpp
@@ -1305,46 +1305,6 @@ void Element::dispatchFocusOutEvent(const AtomicString& eventType, Element* newF
     dispatchScopedEventDispatchMediator(FocusOutEventDispatchMediator::create(FocusEvent::create(eventType, true, false, document().domWindow(), 0, newFocusedElement)));
 }
 
-String Element::textFromChildren()
-{
-    Text* firstTextNode = 0;
-    bool foundMultipleTextNodes = false;
-    unsigned totalLength = 0;
-
-    for (Node* child = firstChild(); child; child = child->nextSibling()) {
-        if (!child->isTextNode())
-            continue;
-        Text* text = toText(child);
-        if (!firstTextNode)
-            firstTextNode = text;
-        else
-            foundMultipleTextNodes = true;
-        unsigned length = text->data().length();
-        if (length > std::numeric_limits<unsigned>::max() - totalLength)
-            return emptyString();
-        totalLength += length;
-    }
-
-    if (!firstTextNode)
-        return emptyString();
-
-    if (firstTextNode && !foundMultipleTextNodes) {
-        firstTextNode->atomize();
-        return firstTextNode->data();
-    }
-
-    StringBuilder content;
-    content.reserveCapacity(totalLength);
-    for (Node* child = firstTextNode; child; child = child->nextSibling()) {
-        if (!child->isTextNode())
-            continue;
-        content.append(toText(child)->data());
-    }
-
-    ASSERT(content.length() == totalLength);
-    return content.toString();
-}
-
 // FIXME(sky): Remove pseudoElementSpecifier.
 RenderStyle* Element::computedStyle(PseudoId pseudoElementSpecifier)
 {
diff --git a/engine/core/dom/Element.h b/engine/core/dom/Element.h
index a1823950b9c..16befaa1b6c 100644
--- a/engine/core/dom/Element.h
+++ b/engine/core/dom/Element.h
@@ -295,8 +295,6 @@ public:
 
     void click();
 
-    String textFromChildren();
-
 protected:
     Element(const QualifiedName& tagName, Document*, ConstructionType);
 
diff --git a/engine/core/dom/Node.cpp b/engine/core/dom/Node.cpp
index e56d01eca8c..4bb54e7f4b9 100644
--- a/engine/core/dom/Node.cpp
+++ b/engine/core/dom/Node.cpp
@@ -908,6 +908,8 @@ ContainerNode* Node::ownerScope() const
 
 String Node::textContent() const
 {
+    if (isTextNode())
+        return toText(this)->data();
     StringBuilder content;
     for (const Node* node = this; node; node = NodeTraversal::next(*node, this)) {
         if (node->isTextNode())
diff --git a/engine/core/html/HTMLStyleElement.cpp b/engine/core/html/HTMLStyleElement.cpp
index e3b70a4faca..757c6127652 100644
--- a/engine/core/html/HTMLStyleElement.cpp
+++ b/engine/core/html/HTMLStyleElement.cpp
@@ -30,6 +30,7 @@
 #include "sky/engine/core/dom/Document.h"
 #include "sky/engine/core/dom/Element.h"
 #include "sky/engine/core/dom/StyleEngine.h"
+#include "sky/engine/core/dom/Text.h"
 #include "sky/engine/core/dom/shadow/ShadowRoot.h"
 #include "sky/engine/core/frame/LocalFrame.h"
 #include "sky/engine/platform/TraceEvent.h"
@@ -124,8 +125,9 @@ void HTMLStyleElement::process()
 
     MediaQueryEvaluator screenEval("screen", true);
     if (screenEval.eval(mediaQueries.get())) {
-        const String& text = textFromChildren();
-        m_sheet = document().styleEngine()->createSheet(this, text);
+        if (hasOneTextChild())
+            toText(firstChild())->atomize();
+        m_sheet = document().styleEngine()->createSheet(this, textContent());
         m_sheet->setMediaQueries(mediaQueries.release());
     }