Fix a crash bug when the UserDefault.xml file is empty. (cocos2d#18626)

* Fix a crash bug when the UserDefault.xml file is empty.

* Fix a crash bug when play multiple timeline animations.

* Fix a crash bug when loading .plist files.

* Fix code style.

Author: monkey256

cocos/base/CCUserDefault.cpp

@@ -57,25 +57,41 @@ static tinyxml2::XMLElement* getXMLNodeForKey(const char* pKey, tinyxml2::XMLEle
 
     do 
     {
-         tinyxml2::XMLDocument* xmlDoc = new (std::nothrow) tinyxml2::XMLDocument();
+        tinyxml2::XMLDocument* xmlDoc = new (std::nothrow) tinyxml2::XMLDocument();
         *doc = xmlDoc;
+        *rootNode = nullptr;
 
         std::string xmlBuffer = FileUtils::getInstance()->getStringFromFile(UserDefault::getInstance()->getXMLFilePath());
 
-        if (xmlBuffer.empty())
+        if (!xmlBuffer.empty())
         {
-            CCLOG("can not read xml file");
-            break;
+            xmlDoc->Parse(xmlBuffer.c_str(), xmlBuffer.size());
+
+            // get root node
+            *rootNode = xmlDoc->RootElement();
         }
-        xmlDoc->Parse(xmlBuffer.c_str(), xmlBuffer.size());
 
-        // get root node
-        *rootNode = xmlDoc->RootElement();
         if (nullptr == *rootNode)
         {
-            CCLOG("read root node error");
-            break;
+            // try to insert xml declaration
+            if (!xmlDoc->FirstChild())
+            {
+                tinyxml2::XMLDeclaration *xmlDeclaration = xmlDoc->NewDeclaration(nullptr);
+                if (nullptr != xmlDeclaration)
+                {
+                    xmlDoc->LinkEndChild(xmlDeclaration);
+                }
+            }
+
+            // create root element
+            tinyxml2::XMLElement *rootEle = xmlDoc->NewElement(USERDEFAULT_ROOT_NAME);
+            if (nullptr == rootEle)
+                break;
+
+            xmlDoc->LinkEndChild(rootEle);
+            *rootNode = rootEle;
         }
+
         // find the node
         curNode = (*rootNode)->FirstChildElement();
         while (nullptr != curNode)
@@ -95,7 +111,7 @@ static tinyxml2::XMLElement* getXMLNodeForKey(const char* pKey, tinyxml2::XMLEle
 
 static void setValueForKey(const char* pKey, const char* pValue)
 {
-     tinyxml2::XMLElement* rootNode;
+    tinyxml2::XMLElement* rootNode;
     tinyxml2::XMLDocument* doc;
     tinyxml2::XMLElement* node;
     // check the params

cocos/editor-support/cocostudio/ActionTimeline/CCFrame.cpp

@@ -149,7 +149,8 @@ TextureFrame* TextureFrame::create()
 }
 
 TextureFrame::TextureFrame()
-    : _textureName("")
+    : _sprite(nullptr)
+    , _textureName("")
 {
 }
 

cocos/platform/CCFileUtils.cpp

@@ -86,6 +86,7 @@ class DictMaker : public SAXDelegator
 public:
     DictMaker()
         : _resultType(SAX_RESULT_NONE)
+        , _state(SAX_NONE)
     {
     }