content: /*
   *  This file is part of AndroidIDE.
   *
   *  AndroidIDE is free software: you can redistribute it and/or modify
   *  it under the terms of the GNU General Public License as published by
   *  the Free Software Foundation, either version 3 of the License, or
   *  (at your option) any later version.
   *
   *  AndroidIDE is distributed in the hope that it will be useful,
   *  but WITHOUT ANY WARRANTY; without even the implied warranty of
   *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   *  GNU General Public License for more details.
   *
   *  You should have received a copy of the GNU General Public License
   *   along with AndroidIDE.  If not, see <https://www.gnu.org/licenses/>.
   */
  
  /*
   * reserved comment block
   * DO NOT REMOVE OR ALTER!
   */
  /*
   * Copyright 2001-2004 The Apache Software Foundation.
   *
   * Licensed 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: UnionPathExpr.java,v 1.2.4.1 2005/09/12 11:34:14 pvedula Exp $
   */
  
  package jaxp.sun.org.apache.xalan.internal.xsltc.compiler;
  
  import java.util.Vector;
  
  import jaxp.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
  import jaxp.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
  import jaxp.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
  import jaxp.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
  import jaxp.sun.org.apache.bcel.internal.generic.InstructionList;
  import jaxp.sun.org.apache.bcel.internal.generic.NEW;
  import jaxp.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
  import jaxp.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
  import jaxp.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
  import jaxp.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
  import jaxp.sun.org.apache.xml.internal.dtm.Axis;
  import jaxp.sun.org.apache.xml.internal.dtm.DTM;
  
  /**
   * @author Jacek Ambroziak
   * @author Santiago Pericas-Geertsen
   */
  final class UnionPathExpr extends Expression {
  
      private final Expression _pathExpr;
      private final Expression _rest;
      private boolean _reverse = false;
  
      // linearization for top level UnionPathExprs
      private Expression[] _components;
  
      public UnionPathExpr(Expression pathExpr, Expression rest) {
          _pathExpr = pathExpr;
          _rest     = rest;
      }
  
      public void setParser(Parser parser) {
          super.setParser(parser);
          // find all expressions in this Union
          final Vector components = new Vector();
          flatten(components);
          final int size = components.size();
          _components = (Expression[])components.toArray(new Expression[size]);
          for (int i = 0; i < size; i++) {
              _components[i].setParser(parser);
              _components[i].setParent(this);
              if (_components[i] instanceof Step) {
                  final Step step = (Step)_components[i];
                  final int axis = step.getAxis();
                  final int type = step.getNodeType();
                  // Put attribute iterators first
                  if ((axis == Axis.ATTRIBUTE) || (type == DTM.ATTRIBUTE_NODE)) {
                      _components[i] = _components[0];
                      _components[0] = step;
                  }
                  // Check if the union contains a reverse iterator
          if (Axis.isReverse(axis)) _reverse = true;
              }
          }
          // No need to reverse anything if another expression lies on top of this
          if (getParent() instanceof Expression) _reverse = false;
      }
  
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
          final int length = _components.length;
          for (int i = 0; i < length; i++) {
              if (_components[i].typeCheck(stable) != Type.NodeSet) {
                  _components[i] = new CastExpr(_components[i], Type.NodeSet);
              }
          }
          return _type = Type.NodeSet;
      }
  
      public String toString() {
          return "union(" + _pathExpr + ", " + _rest + ')';
      }
  
      private void flatten(Vector components) {
          components.addElement(_pathExpr);
          if (_rest != null) {
              if (_rest instanceof UnionPathExpr) {
                  ((UnionPathExpr)_rest).flatten(components);
              }
              else {
                  components.addElement(_rest);
              }
          }
      }
  
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
          final ConstantPoolGen cpg = classGen.getConstantPool();
          final InstructionList il = methodGen.getInstructionList();
  
          final int init = cpg.addMethodref(UNION_ITERATOR_CLASS,
                                            "<init>",
                                            "("+DOM_INTF_SIG+")V");
          final int iter = cpg.addMethodref(UNION_ITERATOR_CLASS,
                                            ADD_ITERATOR,
                                            ADD_ITERATOR_SIG);
  
          // Create the UnionIterator and leave it on the stack
          il.append(new NEW(cpg.addClass(UNION_ITERATOR_CLASS)));
          il.append(DUP);
          il.append(methodGen.loadDOM());
          il.append(new INVOKESPECIAL(init));
  
          // Add the various iterators to the UnionIterator
          final int length = _components.length;
          for (int i = 0; i < length; i++) {
              _components[i].translate(classGen, methodGen);
              il.append(new INVOKEVIRTUAL(iter));
          }
  
          // Order the iterator only if strictly needed
          if (_reverse) {
              final int order = cpg.addInterfaceMethodref(DOM_INTF,
                                                          ORDER_ITERATOR,
                                                          ORDER_ITERATOR_SIG);
              il.append(methodGen.loadDOM());
              il.append(SWAP);
              il.append(methodGen.loadContextNode());
              il.append(new INVOKEINTERFACE(order, 3));
  
          }
      }
  }
  