code: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements. See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership. The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the  "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  /*
   * $Id$
   */
  
  package org.apache.xalan.xsltc.compiler;
  
  import org.apache.bcel.generic.ALOAD;
  import org.apache.bcel.generic.ASTORE;
  import org.apache.bcel.generic.ConstantPoolGen;
  import org.apache.bcel.generic.GETSTATIC;
  import org.apache.bcel.generic.INVOKESTATIC;
  import org.apache.bcel.generic.InstructionList;
  import org.apache.bcel.generic.LocalVariableGen;
  import org.apache.bcel.generic.PUSH;
  import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
  import org.apache.xalan.xsltc.compiler.util.ErrorMsg;
  import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
  import org.apache.xalan.xsltc.compiler.util.Type;
  import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
  import org.apache.xalan.xsltc.compiler.util.Util;
  import org.apache.xml.utils.XML11Char;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   * @author Morten Jorgensen
   */
  final class XslElement extends Instruction {
  
      private String  _prefix;
      private boolean _ignore = false;
      private boolean _isLiteralName = true;
      private AttributeValueTemplate _name; 
      private AttributeValueTemplate _namespace;
  
      /**
       * Displays the contents of the element
       */
      public void display(int indent) {
  	indent(indent);
  	Util.println("Element " + _name);
  	displayContents(indent + IndentIncrement);
      }
  
      /**
       * This method is now deprecated. The new implemation of this class
       * never declares the default NS.
       */
      public boolean declaresDefaultNS() {
  	return false;
      }
  
      public void parseContents(Parser parser) {
  	final SymbolTable stable = parser.getSymbolTable();
  
  	// Handle the 'name' attribute
  	String name = getAttribute("name");
  	if (name == EMPTYSTRING) {
  	    ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_ELEM_NAME_ERR,
  					name, this);
  	    parser.reportError(WARNING, msg);
  	    parseChildren(parser);
  	    _ignore = true; 	// Ignore the element if the QName is invalid
  	    return;
  	}
  
  	// Get namespace attribute
  	String namespace = getAttribute("namespace");
  
  	// Optimize compilation when name is known at compile time
          _isLiteralName = Util.isLiteral(name);
  	if (_isLiteralName) {
              if (!XML11Char.isXML11ValidQName(name)) {
  		ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_ELEM_NAME_ERR,
  					    name, this);
  		parser.reportError(WARNING, msg);
  		parseChildren(parser);
  		_ignore = true; 	// Ignore the element if the QName is invalid
  		return;
  	    }
  
  	    final QName qname = parser.getQNameSafe(name);
  	    String prefix = qname.getPrefix();
  	    String local = qname.getLocalPart();
  	    
  	    if (prefix == null) {
  		prefix = EMPTYSTRING;
  	    }
  
  	    if (!hasAttribute("namespace")) {
  		namespace = lookupNamespace(prefix); 
  		if (namespace == null) {
  		    ErrorMsg err = new ErrorMsg(ErrorMsg.NAMESPACE_UNDEF_ERR,
  						prefix, this);
  		    parser.reportError(WARNING, err);
  		    parseChildren(parser);
  		    _ignore = true; 	// Ignore the element if prefix is undeclared
  		    return;
  		}
  		_prefix = prefix;
  		_namespace = new AttributeValueTemplate(namespace, parser, this);
  	    }
  	    else {
  		if (prefix == EMPTYSTRING) {
          	    if (Util.isLiteral(namespace)) {
  			prefix = lookupPrefix(namespace);
  			if (prefix == null) {
  			    prefix = stable.generateNamespacePrefix();
  			}
  		    }
  
  		    // Prepend prefix to local name
  		    final StringBuffer newName = new StringBuffer(prefix);
  		    if (prefix != EMPTYSTRING) {
  			newName.append(':');
  		    }
  		    name = newName.append(local).toString();
  		}
  		_prefix = prefix;
  		_namespace = new AttributeValueTemplate(namespace, parser, this);
  	    }
  	}
  	else {
              // name attribute contains variable parts.  If there is no namespace
              // attribute, the generated code needs to be prepared to look up
              // any prefix in the stylesheet at run-time.
              _namespace = (namespace == EMPTYSTRING) ? null :
  			 new AttributeValueTemplate(namespace, parser, this);
  	}
  
  	_name = new AttributeValueTemplate(name, parser, this);
  
  	final String useSets = getAttribute("use-attribute-sets");
  	if (useSets.length() > 0) {
              if (!Util.isValidQNames(useSets)) {
                  ErrorMsg err = new ErrorMsg(ErrorMsg.INVALID_QNAME_ERR, useSets, this);
                  parser.reportError(Constants.ERROR, err);	
              }
  	    setFirstElement(new UseAttributeSets(useSets, parser));
  	}
  
  	parseChildren(parser);
      }
  
      /**
       * Run type check on element name & contents
       */
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
  	if (!_ignore) {
  	    _name.typeCheck(stable);
  	    if (_namespace != null) {
  		_namespace.typeCheck(stable);
  	    }
  	}
  	typeCheckContents(stable);
  	return Type.Void;
      }
  
      /**
       * This method is called when the name of the element is known at compile time.
       * In this case, there is no need to inspect the element name at runtime to
       * determine if a prefix exists, needs to be generated, etc.
       */
      public void translateLiteral(ClassGenerator classGen, MethodGenerator methodGen) {
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  
  	if (!_ignore) {
  	    il.append(methodGen.loadHandler());
  	    _name.translate(classGen, methodGen);
  	    il.append(DUP2);
  	    il.append(methodGen.startElement());
  
  	    if (_namespace != null) {
  		il.append(methodGen.loadHandler());
  		il.append(new PUSH(cpg, _prefix));
  		_namespace.translate(classGen,methodGen);
  		il.append(methodGen.namespace());
  	    }
  	}
  
  	translateContents(classGen, methodGen);
  
  	if (!_ignore) {
  	    il.append(methodGen.endElement());
  	}
      }
  
      /**
       * At runtime the compilation of xsl:element results in code that: (i)
       * evaluates the avt for the name, (ii) checks for a prefix in the name
       * (iii) generates a new prefix and create a new qname when necessary
       * (iv) calls startElement() on the handler (v) looks up a uri in the XML
       * when the prefix is not known at compile time (vi) calls namespace() 
       * on the handler (vii) evaluates the contents (viii) calls endElement().
       */
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
  	LocalVariableGen local = null;
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  
  	// Optimize translation if element name is a literal
  	if (_isLiteralName) {
  	    translateLiteral(classGen, methodGen);
  	    return;
  	}
  
  	if (!_ignore) {
         
              // if the qname is an AVT, then the qname has to be checked at runtime if it is a valid qname
              LocalVariableGen nameValue =
                      methodGen.addLocalVariable2("nameValue",
                                                  Util.getJCRefType(STRING_SIG),
                                                  null);
                      
              // store the name into a variable first so _name.translate only needs to be called once  
              _name.translate(classGen, methodGen);
              nameValue.setStart(il.append(new ASTORE(nameValue.getIndex())));
              il.append(new ALOAD(nameValue.getIndex()));
              
              // call checkQName if the name is an AVT
              final int check = cpg.addMethodref(BASIS_LIBRARY_CLASS, "checkQName",
                              "("
                              +STRING_SIG
                              +")V");                 
              il.append(new INVOKESTATIC(check));
              
              // Push handler for call to endElement()
              il.append(methodGen.loadHandler());         
              
              // load name value again
              nameValue.setEnd(il.append(new ALOAD(nameValue.getIndex())));
                      
  	    if (_namespace != null) {
  		_namespace.translate(classGen, methodGen);
  	    }
  	    else {
                  // If name is an AVT and namespace is not specified, need to
                  // look up any prefix in the stylesheet by calling
                  //   BasisLibrary.lookupStylesheetQNameNamespace(
                  //                name, stylesheetNode, ancestorsArray,
                  //                prefixURIsIndexArray, prefixURIPairsArray,
                  //                !ignoreDefaultNamespace)
                  String transletClassName = getXSLTC().getClassName();
                  il.append(DUP);
                  il.append(new PUSH(cpg, getNodeIDForStylesheetNSLookup()));
                  il.append(new GETSTATIC(cpg.addFieldref(
                                               transletClassName,
                                               STATIC_NS_ANCESTORS_ARRAY_FIELD,
                                               NS_ANCESTORS_INDEX_SIG)));
                  il.append(new GETSTATIC(cpg.addFieldref(
                                               transletClassName,
                                               STATIC_PREFIX_URIS_IDX_ARRAY_FIELD,
                                               PREFIX_URIS_IDX_SIG)));
                  il.append(new GETSTATIC(cpg.addFieldref(
                                               transletClassName,
                                               STATIC_PREFIX_URIS_ARRAY_FIELD,
                                               PREFIX_URIS_ARRAY_SIG)));
                  // Default namespace is significant
                  il.append(ICONST_0);
                  il.append(
                      new INVOKESTATIC(
                          cpg.addMethodref(BASIS_LIBRARY_CLASS,
                                             LOOKUP_STYLESHEET_QNAME_NS_REF,
                                             LOOKUP_STYLESHEET_QNAME_NS_SIG)));
  	    }
  
              // Push additional arguments
  	    il.append(methodGen.loadHandler());
  	    il.append(methodGen.loadDOM());
  	    il.append(methodGen.loadCurrentNode());
          
              // Invoke BasisLibrary.startXslElemCheckQName()
              il.append(new INVOKESTATIC(
              cpg.addMethodref(BASIS_LIBRARY_CLASS, "startXslElement",
                      "(" + STRING_SIG 
                      + STRING_SIG 
                      + TRANSLET_OUTPUT_SIG 
                      + DOM_INTF_SIG + "I)" + STRING_SIG)));                
  
  
  	}
  
  	translateContents(classGen, methodGen);
  
  	if (!_ignore) {
  	    il.append(methodGen.endElement());
  	}
      }
  
      /**
       * Override this method to make sure that xsl:attributes are not
       * copied to output if this xsl:element is to be ignored
       */
      public void translateContents(ClassGenerator classGen,
  				  MethodGenerator methodGen) {
  	final int n = elementCount();
  	for (int i = 0; i < n; i++) {
  	    final SyntaxTreeNode item =
  		(SyntaxTreeNode)getContents().elementAt(i);
  	    if (_ignore && item instanceof XslAttribute) continue;
  	    item.translate(classGen, methodGen);
  	}
      }
  
  }
  