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Xalan-Java is an XSLT processor for transforming XML documents into HTML, text, or other XML document types. It implements XSL Transformations (XSLT) Version 1.0 and XML Path Language (XPath) Version 1.0 and can be used from the command line, in an applet or a servlet, or as a module in other program.
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/*
 * 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: DocumentCall.java 1225842 2011-12-30 15:14:35Z mrglavas $
 */

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));
    }

}