Update the first letter when the first line is changed by adding a new text at its start.

Source/core/rendering/RenderBlock.cpp

Index: Source/core/rendering/RenderBlock.cpp
diff --git a/Source/core/rendering/RenderBlock.cpp b/Source/core/rendering/RenderBlock.cpp
index e741c8de44b199f3453f59335b4e22abe7517fc6..f26c57f479a48bcc6675730bca7b122620857b42 100644
--- a/Source/core/rendering/RenderBlock.cpp
+++ b/Source/core/rendering/RenderBlock.cpp
@@ -31,6 +31,7 @@
 #include "core/dom/Element.h"
 #include "core/dom/OverflowEvent.h"
 #include "core/dom/ShadowRoot.h"
+#include "core/dom/Text.h"
 #include "core/dom/WebCoreMemoryInstrumentation.h"
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
@@ -6620,6 +6621,31 @@ void RenderBlock::updateFirstLetterStyle(RenderObject* firstLetterBlock, RenderO
     }
 }
 
+static inline unsigned whiteSpaceLength(PassRefPtr<StringImpl> oldText)

[esprehn, 2013/05/06 20:43:58]

Just take a String not a RefPtr<StringImpl>

+{
+    unsigned length = 0;
+    // Account for leading spaces and punctuation.
+    while (length < oldText->length() && shouldSkipForFirstLetter((*oldText)[length]))
+        length++;
+
+    // Account for first letter.
+    length++;
+
+    // Keep looking for whitespace and allowed punctuation, but avoid
+    // accumulating just whitespace into the :first-letter.
+    for (unsigned scanLength = length; scanLength < oldText->length(); ++scanLength) {
+        UChar c = (*oldText)[scanLength];
+
+        if (!shouldSkipForFirstLetter(c))
+            break;
+
+        if (isPunctuationForFirstLetter(c))
+            length = scanLength + 1;
+    }
+
+    return length;
+}
+
 void RenderBlock::createFirstLetterRenderer(RenderObject* firstLetterBlock, RenderObject* currentChild)
 {
     RenderObject* firstLetterContainer = currentChild->parent();
@@ -6642,26 +6668,8 @@ void RenderBlock::createFirstLetterRenderer(RenderObject* firstLetterBlock, Rend
 
     if (oldText && oldText->length() > 0) {
         unsigned length = 0;
+        length = whiteSpaceLength(oldText);
 
-        // Account for leading spaces and punctuation.
-        while (length < oldText->length() && shouldSkipForFirstLetter((*oldText)[length]))
-            length++;
-
-        // Account for first letter.
-        length++;
-        
-        // Keep looking for whitespace and allowed punctuation, but avoid
-        // accumulating just whitespace into the :first-letter.
-        for (unsigned scanLength = length; scanLength < oldText->length(); ++scanLength) {
-            UChar c = (*oldText)[scanLength]; 
-            
-            if (!shouldSkipForFirstLetter(c))
-                break;
-
-            if (isPunctuationForFirstLetter(c))
-                length = scanLength + 1;
-         }
-         
         // Construct a text fragment for the text after the first letter.
         // This text fragment might be empty.
         RenderTextFragment* remainingText = 
@@ -6701,6 +6709,8 @@ void RenderBlock::updateFirstLetter()
 
     // Drill into inlines looking for our first text child.
     RenderObject* currChild = firstLetterBlock->firstChild();
+    RenderObject* firstLetter = currChild;
+
     while (currChild) {
         if (currChild->isText())
             break;
@@ -6728,6 +6738,35 @@ void RenderBlock::updateFirstLetter()
     // If the child already has style, then it has already been created, so we just want
     // to update it.
     if (currChild->parent()->style()->styleType() == FIRST_LETTER) {
+        RenderText* remainingText = toRenderText(currChild->parent()->nextSibling());
+        // When the first line is changed by adding a new text at its start,
+        // the first letter has to be updated.
+        if (toRenderBoxModelObject(firstLetter)->firstLetterRemainingText() != remainingText) {
+            RenderText* firstLetterText = toRenderText(currChild);
+            RefPtr<StringImpl> updatedTextImp = remainingText->originalText();

[esprehn, 2013/05/06 20:43:58]

Just use String. A String is just a RefPtr to a StringImpl. There's no reason to
ever create your own RefPtr<StringImpl>

+            ASSERT(updatedTextImp);

[esprehn, 2013/05/06 20:43:58]

This assert should be inside whiteSpaceLength

+            unsigned length = 0;
+            if (updatedTextImp && updatedTextImp->length() > 0)

[esprehn, 2013/05/06 20:43:58]

This check should be inside whiteSpaceLength() and you want String isEmpty() not
an explicit length() check. Also checking if updatedTextImpl is null doesn't
make sense, you assert right above this.

unsigned length = whiteSpaceLength(updatedText)

+                length = whiteSpaceLength(updatedTextImp);
+
+            firstLetterText->setText(updatedTextImp->substring(0, length));
+            remainingText->setText(updatedTextImp->substring(length));
+
+            RenderObject* oldRemainingText = currChild->parent()->nextSibling()->nextSibling();

[esprehn, 2013/05/06 20:43:58]

This doesn't look safe at all. How do you know your parent has two siblings?

+            // Replace the previous remaining text with the original text.
+            // because it doesn't have the first letter.
+            if (oldRemainingText->isText()) {
+                RefPtr<StringImpl> oldString = toText(oldRemainingText->node())->dataImpl();

[esprehn, 2013/05/06 20:43:58]

This is going to crash if it's an anonymous text renderer like that created from
a RenderQuote or a RenderCounter.

+
+                // Before calling setText, we need to set m_firstLetter to 0 in order not to delete it.
+                if (toRenderText(oldRemainingText)->isTextFragment())
+                    toRenderTextFragment(oldRemainingText)->setFirstLetter(0);
+
+                toRenderText(oldRemainingText)->setText(oldString);
+            }
+            toRenderBoxModelObject(firstLetter)->setFirstLetterRemainingText(remainingText);
+        }
+
         updateFirstLetterStyle(firstLetterBlock, currChild);
         return;
     }