TEXTAREA: Cutting last line without EOL should not remove the remaining EOL in the previous line.

third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * 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
@@ skipping 602 matching lines @@
     }
 }
 
 bool HTMLTextFormControlElement::lastChangeWasUserEdit() const
 {
     if (!isTextFormControl())
         return false;
     return m_lastChangeWasUserEdit;
 }
 
+PassRefPtrWillBeRawPtr<Node> HTMLTextFormControlElement::createPlaceholderBreakElement() const
+{
+    return HTMLBRElement::create(document());
+}
+
+void HTMLTextFormControlElement::addPlaceholderBreakElementIfNecessary()
+{
+    HTMLElement* innerEditor = innerEditorElement();
+    ASSERT(innerEditor);

[yosin_UTC9, 2016/03/10 08:33:15]

Q: do we need to have this assert? following line de-reference |innerEditor|.

[tkent, 2016/03/10 08:42:38]

We may remove it.  Removed.

+    if (innerEditor->layoutObject() && !innerEditor->layoutObject()->style()->preserveNewline())
+        return;
+    Node* lastChild = innerEditor->lastChild();
+    if (!lastChild || !lastChild->isTextNode())
+        return;
+    if (toText(lastChild)->data().endsWith('\n') || toText(lastChild)->data().endsWith('\r'))
+        innerEditor->appendChild(createPlaceholderBreakElement());
+}
+
 void HTMLTextFormControlElement::setInnerEditorValue(const String& value)
 {
     ASSERT(!openShadowRoot());
     if (!isTextFormControl() || openShadowRoot())
         return;
 
     bool textIsChanged = value != innerEditorValue();
     HTMLElement* innerEditor = innerEditorElement();
     if (!textIsChanged && innerEditor->hasChildren())
         return;
 
     // If the last child is a trailing <br> that's appended below, remove it
     // first so as to enable setInnerText() fast path of updating a text node.
     if (isHTMLBRElement(innerEditor->lastChild()))
         innerEditor->removeChild(innerEditor->lastChild(), ASSERT_NO_EXCEPTION);
 
     // We don't use setTextContent.  It triggers unnecessary paint.
     if (value.isEmpty())
         innerEditor->removeChildren();
     else
         replaceChildrenWithText(innerEditor, value, ASSERT_NO_EXCEPTION);
 
-    if (value.endsWith('\n') || value.endsWith('\r'))
-        innerEditor->appendChild(HTMLBRElement::create(document()));
+    // Add <br> so that we can put the caret at the next line of the last
+    // newline.
+    addPlaceholderBreakElementIfNecessary();
 
     if (textIsChanged && layoutObject()) {
         if (AXObjectCache* cache = document().existingAXObjectCache())
             cache->handleTextFormControlChanged(this);
     }
 }
 
-static String finishText(StringBuilder& result)
-{
-    // Remove one trailing newline; there's always one that's collapsed out by layoutObject.
-    size_t size = result.length();
-    if (size && result[size - 1] == '\n')
-        result.resize(--size);
-    return result.toString();
-}
-
 String HTMLTextFormControlElement::innerEditorValue() const
 {
     ASSERT(!openShadowRoot());
     HTMLElement* innerEditor = innerEditorElement();
     if (!innerEditor || !isTextFormControl())
         return emptyString();
 
     StringBuilder result;
     for (Node& node : NodeTraversal::inclusiveDescendantsOf(*innerEditor)) {
-        if (isHTMLBRElement(node))
-            result.append(newlineCharacter);
-        else if (node.isTextNode())
+        if (isHTMLBRElement(node)) {
+            ASSERT(&node == innerEditor->lastChild());
+            if (&node != innerEditor->lastChild())
+                result.append(newlineCharacter);
+        } else if (node.isTextNode()) {
             result.append(toText(node).data());
+        }
     }
-    return finishText(result);
+    return result.toString();
 }
 
 static void getNextSoftBreak(RootInlineBox*& line, Node*& breakNode, unsigned& breakOffset)
 {
     RootInlineBox* next;
     for (; line; line = next) {
         next = line->nextRootBox();
         if (next && !line->endsWithBreak()) {
             ASSERT(line->lineBreakObj());
             breakNode = line->lineBreakObj().node();
@@ skipping 22 matching lines @@
     unsigned breakOffset;
     RootInlineBox* line = layoutObject->firstRootBox();
     if (!line)
         return value();
 
     getNextSoftBreak(line, breakNode, breakOffset);
 
     StringBuilder result;
     for (Node& node : NodeTraversal::descendantsOf(*innerText)) {
         if (isHTMLBRElement(node)) {
-            result.append(newlineCharacter);
+            ASSERT(&node == innerText->lastChild());
+            if (&node != innerText->lastChild())
+                result.append(newlineCharacter);
         } else if (node.isTextNode()) {
             String data = toText(node).data();
             unsigned length = data.length();
             unsigned position = 0;
             while (breakNode == node && breakOffset <= length) {
                 if (breakOffset > position) {
                     result.append(data, position, breakOffset - position);
                     position = breakOffset;
                     result.append(newlineCharacter);
                 }
                 getNextSoftBreak(line, breakNode, breakOffset);
             }
             result.append(data, position, length - position);
         }
         while (breakNode == node)
             getNextSoftBreak(line, breakNode, breakOffset);
     }
-    return finishText(result);
+    return result.toString();
 }
 
 HTMLTextFormControlElement* enclosingTextFormControl(const Position& position)
 {
     ASSERT(position.isNull() || position.isOffsetInAnchor()
         || position.computeContainerNode() || !position.anchorNode()->shadowHost()
         || (position.anchorNode()->parentNode() && position.anchorNode()->parentNode()->isShadowRoot()));
     return enclosingTextFormControl(position.computeContainerNode());
 }
 
@@ skipping 265 matching lines @@
 }
 
 void HTMLTextFormControlElement::copyNonAttributePropertiesFromElement(const Element& source)
 {
     const HTMLTextFormControlElement& sourceElement = static_cast<const HTMLTextFormControlElement&>(source);
     m_lastChangeWasUserEdit = sourceElement.m_lastChangeWasUserEdit;
     HTMLFormControlElement::copyNonAttributePropertiesFromElement(source);
 }
 
 } // namespace blink