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.ConstantPoolGen;
  import org.apache.bcel.generic.ILOAD;
  import org.apache.bcel.generic.INVOKEINTERFACE;
  import org.apache.bcel.generic.ISTORE;
  import org.apache.bcel.generic.InstructionHandle;
  import org.apache.bcel.generic.InstructionList;
  import org.apache.bcel.generic.LocalVariableGen;
  import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
  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;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   */
  final class ParentPattern extends RelativePathPattern {
      private final Pattern _left;
      private final RelativePathPattern _right;
  		
      public ParentPattern(Pattern left, RelativePathPattern right) {
  	(_left = left).setParent(this);
  	(_right = right).setParent(this);
      }
  
      public void setParser(Parser parser) {
  	super.setParser(parser);
  	_left.setParser(parser);
  	_right.setParser(parser);
      }
      
      public boolean isWildcard() {
  	return false;
      }
  	
      public StepPattern getKernelPattern() {
  	return _right.getKernelPattern();
      }
  	
      public void reduceKernelPattern() {
  	_right.reduceKernelPattern();
      }
  
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
  	_left.typeCheck(stable);
  	return _right.typeCheck(stable);
      }
  
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
  	final ConstantPoolGen cpg = classGen.getConstantPool();
  	final InstructionList il = methodGen.getInstructionList();
  	final LocalVariableGen local =
  	    methodGen.addLocalVariable2("ppt", 
  					Util.getJCRefType(NODE_SIG),
  					null);
  	
  	final org.apache.bcel.generic.Instruction loadLocal =
  	    new ILOAD(local.getIndex());
  	final org.apache.bcel.generic.Instruction storeLocal =
  	    new ISTORE(local.getIndex());
  
  	if (_right.isWildcard()) {
  	    il.append(methodGen.loadDOM());
  	    il.append(SWAP);
  	}
  	else if (_right instanceof StepPattern) {
  	    il.append(DUP);
  	    local.setStart(il.append(storeLocal));
  	    
  	    _right.translate(classGen, methodGen);
  	    
  	    il.append(methodGen.loadDOM());
  	    local.setEnd(il.append(loadLocal));
  	}
  	else {
  	    _right.translate(classGen, methodGen);
  
  	    if (_right instanceof AncestorPattern) {
  		il.append(methodGen.loadDOM());
  		il.append(SWAP);
  	    }
  	}
  
  	final int getParent = cpg.addInterfaceMethodref(DOM_INTF,
  							GET_PARENT,
  							GET_PARENT_SIG);
  	il.append(new INVOKEINTERFACE(getParent, 2));
  
  	final SyntaxTreeNode p = getParent();
  	if (p == null || p instanceof Instruction || 
  	    p instanceof TopLevelElement) 
  	{
  	    _left.translate(classGen, methodGen);
  	}
  	else {
  	    il.append(DUP);
  	    InstructionHandle storeInst = il.append(storeLocal);
  
              if (local.getStart() == null) {
                  local.setStart(storeInst);
              }
  	    _left.translate(classGen, methodGen);
  
  	    il.append(methodGen.loadDOM());
  	    local.setEnd(il.append(loadLocal));
  	}
  
  	methodGen.removeLocalVariable(local);
  	
  	/*
  	 * If _right is an ancestor pattern, backpatch _left false
  	 * list to the loop that searches for more ancestors.
  	 */
  	if (_right instanceof AncestorPattern) {
  	    final AncestorPattern ancestor = (AncestorPattern) _right;
  	    _left.backPatchFalseList(ancestor.getLoopHandle());    // clears list
  	}
  
  	_trueList.append(_right._trueList.append(_left._trueList));
  	_falseList.append(_right._falseList.append(_left._falseList));
      }
  
      public String toString() {
  	return "Parent(" + _left + ", " + _right + ')';
      }
  }
  