Source/core/inspector/DOMPatchSupport.cpp - platform/external/chromium_org/third_party/WebKit - Git at Google

 /*
  * 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
  * copyright notice, this list of conditions and the following disclaimer
  * in the documentation and/or other materials provided with the
  * distribution.
  *     * Neither the name of Google Inc. nor the names of its
  * contributors may be used to endorse or promote products derived from
  * this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "core/inspector/DOMPatchSupport.h"

 #include "HTMLNames.h"
 #include "bindings/v8/ExceptionState.h"
 #include "bindings/v8/ExceptionStatePlaceholder.h"
 #include "core/dom/Attribute.h"
 #include "core/dom/ContextFeatures.h"
 #include "core/dom/Document.h"
 #include "core/dom/DocumentFragment.h"
 #include "core/dom/Node.h"
 #include "core/html/HTMLDocument.h"
 #include "core/html/parser/HTMLDocumentParser.h"
 #include "core/inspector/DOMEditor.h"
 #include "core/inspector/InspectorHistory.h"
 #include "core/xml/parser/XMLDocumentParser.h"
 #include "wtf/Deque.h"
 #include "wtf/HashTraits.h"
 #include "wtf/RefPtr.h"
 #include "wtf/SHA1.h"
 #include "wtf/text/Base64.h"
 #include "wtf/text/CString.h"

 using namespace std;

 namespace WebCore {

 using HTMLNames::bodyTag;
 using HTMLNames::headTag;
 using HTMLNames::htmlTag;

 struct DOMPatchSupport::Digest {
     explicit Digest(Node* node) : m_node(node) { }

     String m_sha1;
     String m_attrsSHA1;
     Node* m_node;
     Vector<OwnPtr<Digest> > m_children;
 };

 void DOMPatchSupport::patchDocument(Document& document, const String& markup)
 {
     InspectorHistory history;
     DOMEditor domEditor(&history);
     DOMPatchSupport patchSupport(&domEditor, document);
     patchSupport.patchDocument(markup);
 }

 DOMPatchSupport::DOMPatchSupport(DOMEditor* domEditor, Document& document)
     : m_domEditor(domEditor)
     , m_document(document)
 {
 }

 void DOMPatchSupport::patchDocument(const String& markup)
 {
     RefPtr<Document> newDocument;
     if (m_document.isHTMLDocument())
         newDocument = HTMLDocument::create();
     else if (m_document.isXHTMLDocument())
         newDocument = HTMLDocument::createXHTML();
     else if (m_document.isSVGDocument())
         newDocument = Document::create();

     ASSERT(newDocument);
     newDocument->setContextFeatures(m_document.contextFeatures());
     RefPtr<DocumentParser> parser;
     if (m_document.isHTMLDocument())
         parser = HTMLDocumentParser::create(toHTMLDocument(newDocument.get()), false);
     else
         parser = XMLDocumentParser::create(newDocument.get(), 0);
     parser->insert(markup); // Use insert() so that the parser will not yield.
     parser->finish();
     parser->detach();

     OwnPtr<Digest> oldInfo = createDigest(m_document.documentElement(), 0);
     OwnPtr<Digest> newInfo = createDigest(newDocument->documentElement(), &m_unusedNodesMap);

     if (!innerPatchNode(oldInfo.get(), newInfo.get(), IGNORE_EXCEPTION)) {
         // Fall back to rewrite.
         m_document.write(markup);
         m_document.close();
     }
 }

 Node* DOMPatchSupport::patchNode(Node* node, const String& markup, ExceptionState& es)
 {
     // Don't parse <html> as a fragment.
     if (node->isDocumentNode() || (node->parentNode() && node->parentNode()->isDocumentNode())) {
         patchDocument(markup);
         return 0;
     }

     Node* previousSibling = node->previousSibling();
     // FIXME: This code should use one of createFragment* in markup.h
     RefPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);
     if (m_document.isHTMLDocument())
         fragment->parseHTML(markup, node->parentElement() ? node->parentElement() : m_document.documentElement());
     else
         fragment->parseXML(markup, node->parentElement() ? node->parentElement() : m_document.documentElement());

     // Compose the old list.
     ContainerNode* parentNode = node->parentNode();
     Vector<OwnPtr<Digest> > oldList;
     for (Node* child = parentNode->firstChild(); child; child = child->nextSibling())
         oldList.append(createDigest(child, 0));

     // Compose the new list.
     String markupCopy = markup.lower();
     Vector<OwnPtr<Digest> > newList;
     for (Node* child = parentNode->firstChild(); child != node; child = child->nextSibling())
         newList.append(createDigest(child, 0));
     for (Node* child = fragment->firstChild(); child; child = child->nextSibling()) {
         if (child->hasTagName(headTag) && !child->firstChild() && markupCopy.find("</head>") == kNotFound)
             continue; // HTML5 parser inserts empty <head> tag whenever it parses <body>
         if (child->hasTagName(bodyTag) && !child->firstChild() && markupCopy.find("</body>") == kNotFound)
             continue; // HTML5 parser inserts empty <body> tag whenever it parses </head>
         newList.append(createDigest(child, &m_unusedNodesMap));
     }
     for (Node* child = node->nextSibling(); child; child = child->nextSibling())
         newList.append(createDigest(child, 0));

     if (!innerPatchChildren(parentNode, oldList, newList, es)) {
         // Fall back to total replace.
         if (!m_domEditor->replaceChild(parentNode, fragment.release(), node, es))
             return 0;
     }
     return previousSibling ? previousSibling->nextSibling() : parentNode->firstChild();
 }

 bool DOMPatchSupport::innerPatchNode(Digest* oldDigest, Digest* newDigest, ExceptionState& es)
 {
     if (oldDigest->m_sha1 == newDigest->m_sha1)
         return true;

     Node* oldNode = oldDigest->m_node;
     Node* newNode = newDigest->m_node;

     if (newNode->nodeType() != oldNode->nodeType() || newNode->nodeName() != oldNode->nodeName())
         return m_domEditor->replaceChild(oldNode->parentNode(), newNode, oldNode, es);

     if (oldNode->nodeValue() != newNode->nodeValue()) {
         if (!m_domEditor->setNodeValue(oldNode, newNode->nodeValue(), es))
             return false;
     }

     if (oldNode->nodeType() != Node::ELEMENT_NODE)
         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->attributeCount()) {
                 const Attribute* attribute = oldElement->attributeItem(0);
                 if (!m_domEditor->removeAttribute(oldElement, attribute->localName(), es))
                     return false;
             }
         }

         // FIXME: Create a function in Element for copying properties. cloneDataFromElement() is close but not enough for this case.
         if (newElement->hasAttributesWithoutUpdate()) {
             size_t numAttrs = newElement->attributeCount();
             for (size_t i = 0; i < numAttrs; ++i) {
                 const Attribute* attribute = newElement->attributeItem(i);
                 if (!m_domEditor->setAttribute(oldElement, attribute->name().localName(), attribute->value(), es))
                     return false;
             }
         }
     }

     bool result = innerPatchChildren(oldElement, oldDigest->m_children, newDigest->m_children, es);
     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)
 {
     ResultMap newMap(newList.size());
     ResultMap oldMap(oldList.size());

     for (size_t i = 0; i < oldMap.size(); ++i) {
         oldMap[i].first = 0;
         oldMap[i].second = 0;
     }

     for (size_t i = 0; i < newMap.size(); ++i) {
         newMap[i].first = 0;
         newMap[i].second = 0;
     }

     // Trim head and tail.
     for (size_t i = 0; i < oldList.size() && i < newList.size() && oldList[i]->m_sha1 == newList[i]->m_sha1; ++i) {
         oldMap[i].first = oldList[i].get();
         oldMap[i].second = i;
         newMap[i].first = newList[i].get();
         newMap[i].second = i;
     }
     for (size_t i = 0; i < oldList.size() && i < newList.size() && oldList[oldList.size() - i - 1]->m_sha1 == newList[newList.size() - i - 1]->m_sha1; ++i) {
         size_t oldIndex = oldList.size() - i - 1;
         size_t newIndex = newList.size() - i - 1;
         oldMap[oldIndex].first = oldList[oldIndex].get();
         oldMap[oldIndex].second = newIndex;
         newMap[newIndex].first = newList[newIndex].get();
         newMap[newIndex].second = oldIndex;
     }

     typedef HashMap<String, Vector<size_t> > DiffTable;
     DiffTable newTable;
     DiffTable oldTable;

     for (size_t i = 0; i < newList.size(); ++i) {
         DiffTable::iterator it = newTable.add(newList[i]->m_sha1, Vector<size_t>()).iterator;
         it->value.append(i);
     }

     for (size_t i = 0; i < oldList.size(); ++i) {
         DiffTable::iterator it = oldTable.add(oldList[i]->m_sha1, Vector<size_t>()).iterator;
         it->value.append(i);
     }

     for (DiffTable::iterator newIt = newTable.begin(); newIt != newTable.end(); ++newIt) {
         if (newIt->value.size() != 1)
             continue;

         DiffTable::iterator oldIt = oldTable.find(newIt->key);
         if (oldIt == oldTable.end() || oldIt->value.size() != 1)
             continue;

         newMap[newIt->value[0]] = make_pair(newList[newIt->value[0]].get(), oldIt->value[0]);
         oldMap[oldIt->value[0]] = make_pair(oldList[oldIt->value[0]].get(), newIt->value[0]);
     }

     for (size_t i = 0; newList.size() > 0 && i < newList.size() - 1; ++i) {
         if (!newMap[i].first || newMap[i + 1].first)
             continue;

         size_t j = newMap[i].second + 1;
         if (j < oldMap.size() && !oldMap[j].first && newList[i + 1]->m_sha1 == oldList[j]->m_sha1) {
             newMap[i + 1] = make_pair(newList[i + 1].get(), j);
             oldMap[j] = make_pair(oldList[j].get(), i + 1);
         }
     }

     for (size_t i = newList.size() - 1; newList.size() > 0 && i > 0; --i) {
         if (!newMap[i].first || newMap[i - 1].first || newMap[i].second <= 0)
             continue;

         size_t j = newMap[i].second - 1;
         if (!oldMap[j].first && newList[i - 1]->m_sha1 == oldList[j]->m_sha1) {
             newMap[i - 1] = make_pair(newList[i - 1].get(), j);
             oldMap[j] = make_pair(oldList[j].get(), i - 1);
         }
     }

 #ifdef DEBUG_DOM_PATCH_SUPPORT
     dumpMap(oldMap, "OLD");
     dumpMap(newMap, "NEW");
 #endif

     return make_pair(oldMap, newMap);
 }

 bool DOMPatchSupport::innerPatchChildren(ContainerNode* parentNode, const Vector<OwnPtr<Digest> >& oldList, const Vector<OwnPtr<Digest> >& newList, ExceptionState& es)
 {
     pair<ResultMap, ResultMap> resultMaps = diff(oldList, newList);
     ResultMap& oldMap = resultMaps.first;
     ResultMap& newMap = resultMaps.second;

     Digest* oldHead = 0;
     Digest* oldBody = 0;

     // 1. First strip everything except for the nodes that retain. Collect pending merges.
     HashMap<Digest*, Digest*> merges;
     HashSet<size_t, WTF::IntHash<size_t>, WTF::UnsignedWithZeroKeyHashTraits<size_t> > usedNewOrdinals;
     for (size_t i = 0; i < oldList.size(); ++i) {
         if (oldMap[i].first) {
             if (usedNewOrdinals.add(oldMap[i].second).isNewEntry)
                 continue;
             oldMap[i].first = 0;
             oldMap[i].second = 0;
         }

         // Always match <head> and <body> tags with each other - we can't remove them from the DOM
         // upon patching.
         if (oldList[i]->m_node->hasTagName(headTag)) {
             oldHead = oldList[i].get();
             continue;
         }
         if (oldList[i]->m_node->hasTagName(bodyTag)) {
             oldBody = oldList[i].get();
             continue;
         }

         // Check if this change is between stable nodes. If it is, consider it as "modified".
         if (!m_unusedNodesMap.contains(oldList[i]->m_sha1) && (!i || oldMap[i - 1].first) && (i == oldMap.size() - 1 || oldMap[i + 1].first)) {
             size_t anchorCandidate = i ? oldMap[i - 1].second + 1 : 0;
             size_t anchorAfter = (i == oldMap.size() - 1) ? anchorCandidate + 1 : oldMap[i + 1].second;
             if (anchorAfter - anchorCandidate == 1 && anchorCandidate < newList.size())
                 merges.set(newList[anchorCandidate].get(), oldList[i].get());
             else {
                 if (!removeChildAndMoveToNew(oldList[i].get(), es))
                     return false;
             }
         } else {
             if (!removeChildAndMoveToNew(oldList[i].get(), es))
                 return false;
         }
     }

     // Mark retained nodes as used, do not reuse node more than once.
     HashSet<size_t, WTF::IntHash<size_t>, WTF::UnsignedWithZeroKeyHashTraits<size_t> >  usedOldOrdinals;
     for (size_t i = 0; i < newList.size(); ++i) {
         if (!newMap[i].first)
             continue;
         size_t oldOrdinal = newMap[i].second;
         if (usedOldOrdinals.contains(oldOrdinal)) {
             // Do not map node more than once
             newMap[i].first = 0;
             newMap[i].second = 0;
             continue;
         }
         usedOldOrdinals.add(oldOrdinal);
         markNodeAsUsed(newMap[i].first);
     }

     // Mark <head> and <body> nodes for merge.
     if (oldHead || oldBody) {
         for (size_t i = 0; i < newList.size(); ++i) {
             if (oldHead && newList[i]->m_node->hasTagName(headTag))
                 merges.set(newList[i].get(), oldHead);
             if (oldBody && newList[i]->m_node->hasTagName(bodyTag))
                 merges.set(newList[i].get(), oldBody);
         }
     }

     // 2. Patch nodes marked for merge.
     for (HashMap<Digest*, Digest*>::iterator it = merges.begin(); it != merges.end(); ++it) {
         if (!innerPatchNode(it->value, it->key, es))
             return false;
     }

     // 3. Insert missing nodes.
     for (size_t i = 0; i < newMap.size(); ++i) {
         if (newMap[i].first || merges.contains(newList[i].get()))
             continue;
         if (!insertBeforeAndMarkAsUsed(parentNode, newList[i].get(), parentNode->childNode(i), es))
             return false;
     }

     // 4. Then put all nodes that retained into their slots (sort by new index).
     for (size_t i = 0; i < oldMap.size(); ++i) {
         if (!oldMap[i].first)
             continue;
         RefPtr<Node> node = oldMap[i].first->m_node;
         Node* anchorNode = parentNode->childNode(oldMap[i].second);
         if (node.get() == anchorNode)
             continue;
         if (node->hasTagName(bodyTag) || node->hasTagName(headTag))
             continue; // Never move head or body, move the rest of the nodes around them.

         if (!m_domEditor->insertBefore(parentNode, node.release(), anchorNode, es))
             return false;
     }
     return true;
 }

 static void addStringToSHA1(SHA1& sha1, const String& string)
 {
     CString cString = string.utf8();
     sha1.addBytes(reinterpret_cast<const uint8_t*>(cString.data()), cString.length());
 }

 PassOwnPtr<DOMPatchSupport::Digest> DOMPatchSupport::createDigest(Node* node, UnusedNodesMap* unusedNodesMap)
 {
     Digest* digest = new Digest(node);

     SHA1 sha1;

     Node::NodeType nodeType = node->nodeType();
     sha1.addBytes(reinterpret_cast<const uint8_t*>(&nodeType), sizeof(nodeType));
     addStringToSHA1(sha1, node->nodeName());
     addStringToSHA1(sha1, node->nodeValue());

     if (node->nodeType() == Node::ELEMENT_NODE) {
         Node* child = node->firstChild();
         while (child) {
             OwnPtr<Digest> childInfo = createDigest(child, unusedNodesMap);
             addStringToSHA1(sha1, childInfo->m_sha1);
             child = child->nextSibling();
             digest->m_children.append(childInfo.release());
         }
         Element* element = toElement(node);

         if (element->hasAttributesWithoutUpdate()) {
             size_t numAttrs = element->attributeCount();
             SHA1 attrsSHA1;
             for (size_t i = 0; i < numAttrs; ++i) {
                 const Attribute* attribute = element->attributeItem(i);
                 addStringToSHA1(attrsSHA1, attribute->name().toString());
                 addStringToSHA1(attrsSHA1, attribute->value());
             }
             Vector<uint8_t, 20> attrsHash;
             attrsSHA1.computeHash(attrsHash);
             digest->m_attrsSHA1 = base64Encode(reinterpret_cast<const char*>(attrsHash.data()), 10);
             addStringToSHA1(sha1, digest->m_attrsSHA1);
         }
     }

     Vector<uint8_t, 20> hash;
     sha1.computeHash(hash);
     digest->m_sha1 = base64Encode(reinterpret_cast<const char*>(hash.data()), 10);
     if (unusedNodesMap)
         unusedNodesMap->add(digest->m_sha1, digest);
     return adoptPtr(digest);
 }

 bool DOMPatchSupport::insertBeforeAndMarkAsUsed(ContainerNode* parentNode, Digest* digest, Node* anchor, ExceptionState& es)
 {
     bool result = m_domEditor->insertBefore(parentNode, digest->m_node, anchor, es);
     markNodeAsUsed(digest);
     return result;
 }

 bool DOMPatchSupport::removeChildAndMoveToNew(Digest* oldDigest, ExceptionState& es)
 {
     RefPtr<Node> oldNode = oldDigest->m_node;
     if (!m_domEditor->removeChild(oldNode->parentNode(), oldNode.get(), es))
         return false;

     // Diff works within levels. In order not to lose the node identity when user
     // prepends his HTML with "<div>" (i.e. all nodes are shifted to the next nested level),
     // prior to dropping the original node on the floor, check whether new DOM has a digest
     // with matching sha1. If it does, replace it with the original DOM chunk. Chances are
     // high that it will get merged back into the original DOM during the further patching.
     UnusedNodesMap::iterator it = m_unusedNodesMap.find(oldDigest->m_sha1);
     if (it != m_unusedNodesMap.end()) {
         Digest* newDigest = it->value;
         Node* newNode = newDigest->m_node;
         if (!m_domEditor->replaceChild(newNode->parentNode(), oldNode, newNode, es))
             return false;
         newDigest->m_node = oldNode.get();
         markNodeAsUsed(newDigest);
         return true;
     }

     for (size_t i = 0; i < oldDigest->m_children.size(); ++i) {
         if (!removeChildAndMoveToNew(oldDigest->m_children[i].get(), es))
             return false;
     }
     return true;
 }

 void DOMPatchSupport::markNodeAsUsed(Digest* digest)
 {
     Deque<Digest*> queue;
     queue.append(digest);
     while (!queue.isEmpty()) {
         Digest* first = queue.takeFirst();
         m_unusedNodesMap.remove(first->m_sha1);
         for (size_t i = 0; i < first->m_children.size(); ++i)
             queue.append(first->m_children[i].get());
     }
 }

 #ifdef DEBUG_DOM_PATCH_SUPPORT
 static String nodeName(Node* node)
 {
     if (node->document().isXHTMLDocument())
          return node->nodeName();
     return node->nodeName().lower();
 }

 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 WebCore
	/*
	* 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
	* copyright notice, this list of conditions and the following disclaimer
	* in the documentation and/or other materials provided with the
	* distribution.
	* * Neither the name of Google Inc. nor the names of its
	* contributors may be used to endorse or promote products derived from
	* this software without specific prior written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "core/inspector/DOMPatchSupport.h"

	#include "HTMLNames.h"
	#include "bindings/v8/ExceptionState.h"
	#include "bindings/v8/ExceptionStatePlaceholder.h"
	#include "core/dom/Attribute.h"
	#include "core/dom/ContextFeatures.h"
	#include "core/dom/Document.h"
	#include "core/dom/DocumentFragment.h"
	#include "core/dom/Node.h"
	#include "core/html/HTMLDocument.h"
	#include "core/html/parser/HTMLDocumentParser.h"
	#include "core/inspector/DOMEditor.h"
	#include "core/inspector/InspectorHistory.h"
	#include "core/xml/parser/XMLDocumentParser.h"
	#include "wtf/Deque.h"
	#include "wtf/HashTraits.h"
	#include "wtf/RefPtr.h"
	#include "wtf/SHA1.h"
	#include "wtf/text/Base64.h"
	#include "wtf/text/CString.h"

	using namespace std;

	namespace WebCore {

	using HTMLNames::bodyTag;
	using HTMLNames::headTag;
	using HTMLNames::htmlTag;

	struct DOMPatchSupport::Digest {
	explicit Digest(Node* node) : m_node(node) { }

	String m_sha1;
	String m_attrsSHA1;
	Node* m_node;
	Vector<OwnPtr<Digest> > m_children;
	};

	void DOMPatchSupport::patchDocument(Document& document, const String& markup)
	{
	InspectorHistory history;
	DOMEditor domEditor(&history);
	DOMPatchSupport patchSupport(&domEditor, document);
	patchSupport.patchDocument(markup);
	}

	DOMPatchSupport::DOMPatchSupport(DOMEditor* domEditor, Document& document)
	: m_domEditor(domEditor)
	, m_document(document)
	{
	}

	void DOMPatchSupport::patchDocument(const String& markup)
	{
	RefPtr<Document> newDocument;
	if (m_document.isHTMLDocument())
	newDocument = HTMLDocument::create();
	else if (m_document.isXHTMLDocument())
	newDocument = HTMLDocument::createXHTML();
	else if (m_document.isSVGDocument())
	newDocument = Document::create();

	ASSERT(newDocument);
	newDocument->setContextFeatures(m_document.contextFeatures());
	RefPtr<DocumentParser> parser;
	if (m_document.isHTMLDocument())
	parser = HTMLDocumentParser::create(toHTMLDocument(newDocument.get()), false);
	else
	parser = XMLDocumentParser::create(newDocument.get(), 0);
	parser->insert(markup); // Use insert() so that the parser will not yield.
	parser->finish();
	parser->detach();

	OwnPtr<Digest> oldInfo = createDigest(m_document.documentElement(), 0);
	OwnPtr<Digest> newInfo = createDigest(newDocument->documentElement(), &m_unusedNodesMap);

	if (!innerPatchNode(oldInfo.get(), newInfo.get(), IGNORE_EXCEPTION)) {
	// Fall back to rewrite.
	m_document.write(markup);
	m_document.close();
	}
	}

	Node* DOMPatchSupport::patchNode(Node* node, const String& markup, ExceptionState& es)
	{
	// Don't parse <html> as a fragment.
	if (node->isDocumentNode() \|\| (node->parentNode() && node->parentNode()->isDocumentNode())) {
	patchDocument(markup);
	return 0;
	}

	Node* previousSibling = node->previousSibling();
	// FIXME: This code should use one of createFragment* in markup.h
	RefPtr<DocumentFragment> fragment = DocumentFragment::create(m_document);
	if (m_document.isHTMLDocument())
	fragment->parseHTML(markup, node->parentElement() ? node->parentElement() : m_document.documentElement());
	else
	fragment->parseXML(markup, node->parentElement() ? node->parentElement() : m_document.documentElement());

	// Compose the old list.
	ContainerNode* parentNode = node->parentNode();
	Vector<OwnPtr<Digest> > oldList;
	for (Node* child = parentNode->firstChild(); child; child = child->nextSibling())
	oldList.append(createDigest(child, 0));

	// Compose the new list.
	String markupCopy = markup.lower();
	Vector<OwnPtr<Digest> > newList;
	for (Node* child = parentNode->firstChild(); child != node; child = child->nextSibling())
	newList.append(createDigest(child, 0));
	for (Node* child = fragment->firstChild(); child; child = child->nextSibling()) {
	if (child->hasTagName(headTag) && !child->firstChild() && markupCopy.find("</head>") == kNotFound)
	continue; // HTML5 parser inserts empty <head> tag whenever it parses <body>
	if (child->hasTagName(bodyTag) && !child->firstChild() && markupCopy.find("</body>") == kNotFound)
	continue; // HTML5 parser inserts empty <body> tag whenever it parses </head>
	newList.append(createDigest(child, &m_unusedNodesMap));
	}
	for (Node* child = node->nextSibling(); child; child = child->nextSibling())
	newList.append(createDigest(child, 0));

	if (!innerPatchChildren(parentNode, oldList, newList, es)) {
	// Fall back to total replace.
	if (!m_domEditor->replaceChild(parentNode, fragment.release(), node, es))
	return 0;
	}
	return previousSibling ? previousSibling->nextSibling() : parentNode->firstChild();
	}

	bool DOMPatchSupport::innerPatchNode(Digest* oldDigest, Digest* newDigest, ExceptionState& es)
	{
	if (oldDigest->m_sha1 == newDigest->m_sha1)
	return true;

	Node* oldNode = oldDigest->m_node;
	Node* newNode = newDigest->m_node;

	if (newNode->nodeType() != oldNode->nodeType() \|\| newNode->nodeName() != oldNode->nodeName())
	return m_domEditor->replaceChild(oldNode->parentNode(), newNode, oldNode, es);

	if (oldNode->nodeValue() != newNode->nodeValue()) {
	if (!m_domEditor->setNodeValue(oldNode, newNode->nodeValue(), es))
	return false;
	}

	if (oldNode->nodeType() != Node::ELEMENT_NODE)
	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->attributeCount()) {
	const Attribute* attribute = oldElement->attributeItem(0);
	if (!m_domEditor->removeAttribute(oldElement, attribute->localName(), es))
	return false;
	}
	}

	// FIXME: Create a function in Element for copying properties. cloneDataFromElement() is close but not enough for this case.
	if (newElement->hasAttributesWithoutUpdate()) {
	size_t numAttrs = newElement->attributeCount();
	for (size_t i = 0; i < numAttrs; ++i) {
	const Attribute* attribute = newElement->attributeItem(i);
	if (!m_domEditor->setAttribute(oldElement, attribute->name().localName(), attribute->value(), es))
	return false;
	}
	}
	}

	bool result = innerPatchChildren(oldElement, oldDigest->m_children, newDigest->m_children, es);
	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)
	{
	ResultMap newMap(newList.size());
	ResultMap oldMap(oldList.size());

	for (size_t i = 0; i < oldMap.size(); ++i) {
	oldMap[i].first = 0;
	oldMap[i].second = 0;
	}

	for (size_t i = 0; i < newMap.size(); ++i) {
	newMap[i].first = 0;
	newMap[i].second = 0;
	}

	// Trim head and tail.
	for (size_t i = 0; i < oldList.size() && i < newList.size() && oldList[i]->m_sha1 == newList[i]->m_sha1; ++i) {
	oldMap[i].first = oldList[i].get();
	oldMap[i].second = i;
	newMap[i].first = newList[i].get();
	newMap[i].second = i;
	}
	for (size_t i = 0; i < oldList.size() && i < newList.size() && oldList[oldList.size() - i - 1]->m_sha1 == newList[newList.size() - i - 1]->m_sha1; ++i) {
	size_t oldIndex = oldList.size() - i - 1;
	size_t newIndex = newList.size() - i - 1;
	oldMap[oldIndex].first = oldList[oldIndex].get();
	oldMap[oldIndex].second = newIndex;
	newMap[newIndex].first = newList[newIndex].get();
	newMap[newIndex].second = oldIndex;
	}

	typedef HashMap<String, Vector<size_t> > DiffTable;
	DiffTable newTable;
	DiffTable oldTable;

	for (size_t i = 0; i < newList.size(); ++i) {
	DiffTable::iterator it = newTable.add(newList[i]->m_sha1, Vector<size_t>()).iterator;
	it->value.append(i);
	}

	for (size_t i = 0; i < oldList.size(); ++i) {
	DiffTable::iterator it = oldTable.add(oldList[i]->m_sha1, Vector<size_t>()).iterator;
	it->value.append(i);
	}

	for (DiffTable::iterator newIt = newTable.begin(); newIt != newTable.end(); ++newIt) {
	if (newIt->value.size() != 1)
	continue;

	DiffTable::iterator oldIt = oldTable.find(newIt->key);
	if (oldIt == oldTable.end() \|\| oldIt->value.size() != 1)
	continue;

	newMap[newIt->value[0]] = make_pair(newList[newIt->value[0]].get(), oldIt->value[0]);
	oldMap[oldIt->value[0]] = make_pair(oldList[oldIt->value[0]].get(), newIt->value[0]);
	}

	for (size_t i = 0; newList.size() > 0 && i < newList.size() - 1; ++i) {
	if (!newMap[i].first \|\| newMap[i + 1].first)
	continue;

	size_t j = newMap[i].second + 1;
	if (j < oldMap.size() && !oldMap[j].first && newList[i + 1]->m_sha1 == oldList[j]->m_sha1) {
	newMap[i + 1] = make_pair(newList[i + 1].get(), j);
	oldMap[j] = make_pair(oldList[j].get(), i + 1);
	}
	}

	for (size_t i = newList.size() - 1; newList.size() > 0 && i > 0; --i) {
	if (!newMap[i].first \|\| newMap[i - 1].first \|\| newMap[i].second <= 0)
	continue;

	size_t j = newMap[i].second - 1;
	if (!oldMap[j].first && newList[i - 1]->m_sha1 == oldList[j]->m_sha1) {
	newMap[i - 1] = make_pair(newList[i - 1].get(), j);
	oldMap[j] = make_pair(oldList[j].get(), i - 1);
	}
	}

	#ifdef DEBUG_DOM_PATCH_SUPPORT
	dumpMap(oldMap, "OLD");
	dumpMap(newMap, "NEW");
	#endif

	return make_pair(oldMap, newMap);
	}

	bool DOMPatchSupport::innerPatchChildren(ContainerNode* parentNode, const Vector<OwnPtr<Digest> >& oldList, const Vector<OwnPtr<Digest> >& newList, ExceptionState& es)
	{
	pair<ResultMap, ResultMap> resultMaps = diff(oldList, newList);
	ResultMap& oldMap = resultMaps.first;
	ResultMap& newMap = resultMaps.second;

	Digest* oldHead = 0;
	Digest* oldBody = 0;

	// 1. First strip everything except for the nodes that retain. Collect pending merges.
	HashMap<Digest, Digest> merges;
	HashSet<size_t, WTF::IntHash<size_t>, WTF::UnsignedWithZeroKeyHashTraits<size_t> > usedNewOrdinals;
	for (size_t i = 0; i < oldList.size(); ++i) {
	if (oldMap[i].first) {
	if (usedNewOrdinals.add(oldMap[i].second).isNewEntry)
	continue;
	oldMap[i].first = 0;
	oldMap[i].second = 0;
	}

	// Always match <head> and <body> tags with each other - we can't remove them from the DOM
	// upon patching.
	if (oldList[i]->m_node->hasTagName(headTag)) {
	oldHead = oldList[i].get();
	continue;
	}
	if (oldList[i]->m_node->hasTagName(bodyTag)) {
	oldBody = oldList[i].get();
	continue;
	}

	// Check if this change is between stable nodes. If it is, consider it as "modified".
	if (!m_unusedNodesMap.contains(oldList[i]->m_sha1) && (!i \|\| oldMap[i - 1].first) && (i == oldMap.size() - 1 \|\| oldMap[i + 1].first)) {
	size_t anchorCandidate = i ? oldMap[i - 1].second + 1 : 0;
	size_t anchorAfter = (i == oldMap.size() - 1) ? anchorCandidate + 1 : oldMap[i + 1].second;
	if (anchorAfter - anchorCandidate == 1 && anchorCandidate < newList.size())
	merges.set(newList[anchorCandidate].get(), oldList[i].get());
	else {
	if (!removeChildAndMoveToNew(oldList[i].get(), es))
	return false;
	}
	} else {
	if (!removeChildAndMoveToNew(oldList[i].get(), es))
	return false;
	}
	}

	// Mark retained nodes as used, do not reuse node more than once.
	HashSet<size_t, WTF::IntHash<size_t>, WTF::UnsignedWithZeroKeyHashTraits<size_t> > usedOldOrdinals;
	for (size_t i = 0; i < newList.size(); ++i) {
	if (!newMap[i].first)
	continue;
	size_t oldOrdinal = newMap[i].second;
	if (usedOldOrdinals.contains(oldOrdinal)) {
	// Do not map node more than once
	newMap[i].first = 0;
	newMap[i].second = 0;
	continue;
	}
	usedOldOrdinals.add(oldOrdinal);
	markNodeAsUsed(newMap[i].first);
	}

	// Mark <head> and <body> nodes for merge.
	if (oldHead \|\| oldBody) {
	for (size_t i = 0; i < newList.size(); ++i) {
	if (oldHead && newList[i]->m_node->hasTagName(headTag))
	merges.set(newList[i].get(), oldHead);
	if (oldBody && newList[i]->m_node->hasTagName(bodyTag))
	merges.set(newList[i].get(), oldBody);
	}
	}

	// 2. Patch nodes marked for merge.
	for (HashMap<Digest, Digest>::iterator it = merges.begin(); it != merges.end(); ++it) {
	if (!innerPatchNode(it->value, it->key, es))
	return false;
	}

	// 3. Insert missing nodes.
	for (size_t i = 0; i < newMap.size(); ++i) {
	if (newMap[i].first \|\| merges.contains(newList[i].get()))
	continue;
	if (!insertBeforeAndMarkAsUsed(parentNode, newList[i].get(), parentNode->childNode(i), es))
	return false;
	}

	// 4. Then put all nodes that retained into their slots (sort by new index).
	for (size_t i = 0; i < oldMap.size(); ++i) {
	if (!oldMap[i].first)
	continue;
	RefPtr<Node> node = oldMap[i].first->m_node;
	Node* anchorNode = parentNode->childNode(oldMap[i].second);
	if (node.get() == anchorNode)
	continue;
	if (node->hasTagName(bodyTag) \|\| node->hasTagName(headTag))
	continue; // Never move head or body, move the rest of the nodes around them.

	if (!m_domEditor->insertBefore(parentNode, node.release(), anchorNode, es))
	return false;
	}
	return true;
	}

	static void addStringToSHA1(SHA1& sha1, const String& string)
	{
	CString cString = string.utf8();
	sha1.addBytes(reinterpret_cast<const uint8_t*>(cString.data()), cString.length());
	}

	PassOwnPtr<DOMPatchSupport::Digest> DOMPatchSupport::createDigest(Node* node, UnusedNodesMap* unusedNodesMap)
	{
	Digest* digest = new Digest(node);

	SHA1 sha1;

	Node::NodeType nodeType = node->nodeType();
	sha1.addBytes(reinterpret_cast<const uint8_t*>(&nodeType), sizeof(nodeType));
	addStringToSHA1(sha1, node->nodeName());
	addStringToSHA1(sha1, node->nodeValue());

	if (node->nodeType() == Node::ELEMENT_NODE) {
	Node* child = node->firstChild();
	while (child) {
	OwnPtr<Digest> childInfo = createDigest(child, unusedNodesMap);
	addStringToSHA1(sha1, childInfo->m_sha1);
	child = child->nextSibling();
	digest->m_children.append(childInfo.release());
	}
	Element* element = toElement(node);

	if (element->hasAttributesWithoutUpdate()) {
	size_t numAttrs = element->attributeCount();
	SHA1 attrsSHA1;
	for (size_t i = 0; i < numAttrs; ++i) {
	const Attribute* attribute = element->attributeItem(i);
	addStringToSHA1(attrsSHA1, attribute->name().toString());
	addStringToSHA1(attrsSHA1, attribute->value());
	}
	Vector<uint8_t, 20> attrsHash;
	attrsSHA1.computeHash(attrsHash);
	digest->m_attrsSHA1 = base64Encode(reinterpret_cast<const char*>(attrsHash.data()), 10);
	addStringToSHA1(sha1, digest->m_attrsSHA1);
	}
	}

	Vector<uint8_t, 20> hash;
	sha1.computeHash(hash);
	digest->m_sha1 = base64Encode(reinterpret_cast<const char*>(hash.data()), 10);
	if (unusedNodesMap)
	unusedNodesMap->add(digest->m_sha1, digest);
	return adoptPtr(digest);
	}

	bool DOMPatchSupport::insertBeforeAndMarkAsUsed(ContainerNode* parentNode, Digest* digest, Node* anchor, ExceptionState& es)
	{
	bool result = m_domEditor->insertBefore(parentNode, digest->m_node, anchor, es);
	markNodeAsUsed(digest);
	return result;
	}

	bool DOMPatchSupport::removeChildAndMoveToNew(Digest* oldDigest, ExceptionState& es)
	{
	RefPtr<Node> oldNode = oldDigest->m_node;
	if (!m_domEditor->removeChild(oldNode->parentNode(), oldNode.get(), es))
	return false;

	// Diff works within levels. In order not to lose the node identity when user
	// prepends his HTML with "<div>" (i.e. all nodes are shifted to the next nested level),
	// prior to dropping the original node on the floor, check whether new DOM has a digest
	// with matching sha1. If it does, replace it with the original DOM chunk. Chances are
	// high that it will get merged back into the original DOM during the further patching.
	UnusedNodesMap::iterator it = m_unusedNodesMap.find(oldDigest->m_sha1);
	if (it != m_unusedNodesMap.end()) {
	Digest* newDigest = it->value;
	Node* newNode = newDigest->m_node;
	if (!m_domEditor->replaceChild(newNode->parentNode(), oldNode, newNode, es))
	return false;
	newDigest->m_node = oldNode.get();
	markNodeAsUsed(newDigest);
	return true;
	}

	for (size_t i = 0; i < oldDigest->m_children.size(); ++i) {
	if (!removeChildAndMoveToNew(oldDigest->m_children[i].get(), es))
	return false;
	}
	return true;
	}

	void DOMPatchSupport::markNodeAsUsed(Digest* digest)
	{
	Deque<Digest*> queue;
	queue.append(digest);
	while (!queue.isEmpty()) {
	Digest* first = queue.takeFirst();
	m_unusedNodesMap.remove(first->m_sha1);
	for (size_t i = 0; i < first->m_children.size(); ++i)
	queue.append(first->m_children[i].get());
	}
	}

	#ifdef DEBUG_DOM_PATCH_SUPPORT
	static String nodeName(Node* node)
	{
	if (node->document().isXHTMLDocument())
	return node->nodeName();
	return node->nodeName().lower();
	}

	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 WebCore