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 java.util.Vector;
  
  import org.apache.bcel.generic.ConstantPoolGen;
  import org.apache.bcel.generic.GETFIELD;
  import org.apache.bcel.generic.INVOKESTATIC;
  import org.apache.bcel.generic.InstructionList;
  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;
  
  /**
   * @author Jacek Ambroziak
   * @author Morten Jorgensen
   */
  final class DocumentCall extends FunctionCall {
  
      private Expression _arg1 = null;
      private Expression _arg2 = null;
      private Type       _arg1Type;
  
      /**
       * Default function call constructor
       */
      public DocumentCall(QName fname, Vector arguments) {
          super(fname, arguments);
      }
  
      /**
       * Type checks the arguments passed to the document() function. The first
       * argument can be any type (we must cast it to a string) and contains the
       * URI of the document
       */
      public Type typeCheck(SymbolTable stable) throws TypeCheckError {
          // At least one argument - two at most
          final int ac = argumentCount();
          if ((ac < 1) || (ac > 2)) {
              ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_ARG_ERR, this);
              throw new TypeCheckError(msg);
          }
          if (getStylesheet() == null) {
              ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_ARG_ERR, this);
              throw new TypeCheckError(msg);
          }
  
          // Parse the first argument 
          _arg1 = argument(0);
  
          if (_arg1 == null) {// should not happened 
              ErrorMsg msg = new ErrorMsg(ErrorMsg.DOCUMENT_ARG_ERR, this);
              throw new TypeCheckError(msg);
          }
  
          _arg1Type = _arg1.typeCheck(stable);
          if ((_arg1Type != Type.NodeSet) && (_arg1Type != Type.String)) {
              _arg1 = new CastExpr(_arg1, Type.String);
          }
  
          // Parse the second argument 
          if (ac == 2) {
              _arg2 = argument(1);
  
              if (_arg2 == null) {// should not happened 
                  ErrorMsg msg = new ErrorMsg(ErrorMsg.DOCUMENT_ARG_ERR, this);
                  throw new TypeCheckError(msg);
              }
  
              final Type arg2Type = _arg2.typeCheck(stable);
  
              if (arg2Type.identicalTo(Type.Node)) {
                  _arg2 = new CastExpr(_arg2, Type.NodeSet);
              } else if (arg2Type.identicalTo(Type.NodeSet)) {
                  // falls through
              } else {
                  ErrorMsg msg = new ErrorMsg(ErrorMsg.DOCUMENT_ARG_ERR, this);
                  throw new TypeCheckError(msg);
              }
          }
  
          return _type = Type.NodeSet;
      }
      
      /**
       * Translates the document() function call to a call to LoadDocument()'s
       * static method document().
       */
      public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
          final ConstantPoolGen cpg = classGen.getConstantPool();
          final InstructionList il = methodGen.getInstructionList();
          final int ac = argumentCount();
  
          final int domField = cpg.addFieldref(classGen.getClassName(),
                                               DOM_FIELD,
                                               DOM_INTF_SIG);
            
          String docParamList = null;
          if (ac == 1) {
             // documentF(Object,String,AbstractTranslet,DOM)
             docParamList = "("+OBJECT_SIG+STRING_SIG+TRANSLET_SIG+DOM_INTF_SIG
                           +")"+NODE_ITERATOR_SIG;
          } else { //ac == 2; ac < 1 or as >2  was tested in typeChec()
             // documentF(Object,DTMAxisIterator,String,AbstractTranslet,DOM)
             docParamList = "("+OBJECT_SIG+NODE_ITERATOR_SIG+STRING_SIG
                           +TRANSLET_SIG+DOM_INTF_SIG+")"+NODE_ITERATOR_SIG;  
          }
          final int docIdx = cpg.addMethodref(LOAD_DOCUMENT_CLASS, "documentF",
                                              docParamList);
  
  
          // The URI can be either a node-set or something else cast to a string
          _arg1.translate(classGen, methodGen);
          if (_arg1Type == Type.NodeSet) {
              _arg1.startIterator(classGen, methodGen);
          }
  
          if (ac == 2) {
              //_arg2 == null was tested in typeChec()
              _arg2.translate(classGen, methodGen);
              _arg2.startIterator(classGen, methodGen);       
          }
      
          // Process the rest of the parameters on the stack
          il.append(new PUSH(cpg, getStylesheet().getSystemId()));
          il.append(classGen.loadTranslet());
          il.append(DUP);
          il.append(new GETFIELD(domField));
          il.append(new INVOKESTATIC(docIdx));
      }
  
  }
  