Make Element::attributes() less error-prone and simplify call sites

Source/core/inspector/DOMPatchSupport.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 170 matching lines @@
     }
 
     if (!oldNode->isElementNode())
         return true;
 
     // Patch attributes
     Element* oldElement = toElement(oldNode);
     Element* newElement = toElement(newNode);
     if (oldDigest->m_attrsSHA1 != newDigest->m_attrsSHA1) {
         // FIXME: Create a function in Element for removing all properties. Take in account whether did/willModifyAttribute are important.
-        if (oldElement->hasAttributesWithoutUpdate()) {
-            while (oldElement->attributes().size()) {
-                const Attribute& attribute = oldElement->attributes().at(0);
-                if (!m_domEditor->removeAttribute(oldElement, attribute.localName(), exceptionState))
-                    return false;
-            }
+        while (oldElement->attributesWithoutUpdate().size()) {
+            const Attribute& attribute = oldElement->attributesWithoutUpdate().at(0);
+            if (!m_domEditor->removeAttribute(oldElement, attribute.localName(), exceptionState))
+                return false;
         }
 
         // FIXME: Create a function in Element for copying properties. cloneDataFromElement() is close but not enough for this case.
-        if (newElement->hasAttributesWithoutUpdate()) {
-            AttributeCollection attributes = newElement->attributes();
-            AttributeCollection::const_iterator end = attributes.end();
-            for (AttributeCollection::const_iterator it = attributes.begin(); it != end; ++it) {
-                if (!m_domEditor->setAttribute(oldElement, it->name().localName(), it->value(), exceptionState))
-                    return false;
-            }
+        AttributeCollection attributes = newElement->attributesWithoutUpdate();
+        AttributeCollection::const_iterator end = attributes.end();
+        for (AttributeCollection::const_iterator it = attributes.begin(); it != end; ++it) {
+            if (!m_domEditor->setAttribute(oldElement, it->name().localName(), it->value(), exceptionState))
+                return false;
         }
     }
 
     bool result = innerPatchChildren(oldElement, oldDigest->m_children, newDigest->m_children, exceptionState);
     m_unusedNodesMap.remove(newDigest->m_sha1);
     return result;
 }
 
 pair<DOMPatchSupport::ResultMap, DOMPatchSupport::ResultMap>
 DOMPatchSupport::diff(const Vector<OwnPtr<Digest> >& oldList, const Vector<OwnPtr<Digest> >& newList)
@@ skipping 205 matching lines @@
     if (node->isElementNode()) {
         Element& element = toElement(*node);
         Node* child = element.firstChild();
         while (child) {
             OwnPtr<Digest> childInfo = createDigest(child, unusedNodesMap);
             addStringToDigestor(digestor.get(), childInfo->m_sha1);
             child = child->nextSibling();
             digest->m_children.append(childInfo.release());
         }
 
-        if (element.hasAttributesWithoutUpdate()) {
+        AttributeCollection attributes = element.attributesWithoutUpdate();
+        if (!attributes.isEmpty()) {
             OwnPtr<blink::WebCryptoDigestor> attrsDigestor = createDigestor(HashAlgorithmSha1);
-            AttributeCollection attributes = element.attributes();
             AttributeCollection::const_iterator end = attributes.end();
             for (AttributeCollection::const_iterator it = attributes.begin(); it != end; ++it) {
                 addStringToDigestor(attrsDigestor.get(), it->name().toString());
                 addStringToDigestor(attrsDigestor.get(), it->value().string());
             }
             finishDigestor(attrsDigestor.get(), digestResult);
             digest->m_attrsSHA1 = base64Encode(reinterpret_cast<const char*>(digestResult.data()), 10);
             addStringToDigestor(digestor.get(), digest->m_attrsSHA1);
             digestResult.clear();
         }
@@ skipping 65 matching lines @@
 void DOMPatchSupport::dumpMap(const ResultMap& map, const String& name)
 {
     fprintf(stderr, "\n\n");
     for (size_t i = 0; i < map.size(); ++i)
         fprintf(stderr, "%s[%lu]: %s (%p) - [%lu]\n", name.utf8().data(), i, map[i].first ? nodeName(map[i].first->m_node).utf8().data() : "", map[i].first, map[i].second);
 }
 #endif
 
 } // namespace blink