001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements. See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership. The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the "License");
007 * you may not use this file except in compliance with the License.
008 * You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018 /*
019 * $Id: FilteredAbsoluteLocationPath.java 468650 2006-10-28 07:03:30Z minchau $
020 */
021
022 package org.apache.xalan.xsltc.compiler;
023
024 import org.apache.bcel.generic.ALOAD;
025 import org.apache.bcel.generic.ASTORE;
026 import org.apache.bcel.generic.ConstantPoolGen;
027 import org.apache.bcel.generic.INVOKEINTERFACE;
028 import org.apache.bcel.generic.INVOKESPECIAL;
029 import org.apache.bcel.generic.InstructionList;
030 import org.apache.bcel.generic.LocalVariableGen;
031 import org.apache.bcel.generic.NEW;
032 import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
033 import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
034 import org.apache.xalan.xsltc.compiler.util.NodeType;
035 import org.apache.xalan.xsltc.compiler.util.Type;
036 import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
037 import org.apache.xalan.xsltc.compiler.util.Util;
038
039 /**
040 * @author G. Todd Miller
041 */
042 final class FilteredAbsoluteLocationPath extends Expression {
043 private Expression _path; // may be null
044
045 public FilteredAbsoluteLocationPath() {
046 _path = null;
047 }
048
049 public FilteredAbsoluteLocationPath(Expression path) {
050 _path = path;
051 if (path != null) {
052 _path.setParent(this);
053 }
054 }
055
056 public void setParser(Parser parser) {
057 super.setParser(parser);
058 if (_path != null) {
059 _path.setParser(parser);
060 }
061 }
062
063 public Expression getPath() {
064 return(_path);
065 }
066
067 public String toString() {
068 return "FilteredAbsoluteLocationPath(" +
069 (_path != null ? _path.toString() : "null") + ')';
070 }
071
072 public Type typeCheck(SymbolTable stable) throws TypeCheckError {
073 if (_path != null) {
074 final Type ptype = _path.typeCheck(stable);
075 if (ptype instanceof NodeType) { // promote to node-set
076 _path = new CastExpr(_path, Type.NodeSet);
077 }
078 }
079 return _type = Type.NodeSet;
080 }
081
082 public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
083 final ConstantPoolGen cpg = classGen.getConstantPool();
084 final InstructionList il = methodGen.getInstructionList();
085 if (_path != null) {
086 final int initDFI = cpg.addMethodref(DUP_FILTERED_ITERATOR,
087 "<init>",
088 "("
089 + NODE_ITERATOR_SIG
090 + ")V");
091
092 // Backwards branches are prohibited if an uninitialized object is
093 // on the stack by section 4.9.4 of the JVM Specification, 2nd Ed.
094 // We don't know whether this code might contain backwards branches,
095 // so we mustn't create the new object until after we've created
096 // the suspect arguments to its constructor. Instead we calculate
097 // the values of the arguments to the constructor first, store them
098 // in temporary variables, create the object and reload the
099 // arguments from the temporaries to avoid the problem.
100
101 // Compile relative path iterator(s)
102 LocalVariableGen pathTemp =
103 methodGen.addLocalVariable("filtered_absolute_location_path_tmp",
104 Util.getJCRefType(NODE_ITERATOR_SIG),
105 null, null);
106 _path.translate(classGen, methodGen);
107 pathTemp.setStart(il.append(new ASTORE(pathTemp.getIndex())));
108
109 // Create new Dup Filter Iterator
110 il.append(new NEW(cpg.addClass(DUP_FILTERED_ITERATOR)));
111 il.append(DUP);
112 pathTemp.setEnd(il.append(new ALOAD(pathTemp.getIndex())));
113
114 // Initialize Dup Filter Iterator with iterator from the stack
115 il.append(new INVOKESPECIAL(initDFI));
116 }
117 else {
118 final int git = cpg.addInterfaceMethodref(DOM_INTF,
119 "getIterator",
120 "()"+NODE_ITERATOR_SIG);
121 il.append(methodGen.loadDOM());
122 il.append(new INVOKEINTERFACE(git, 1));
123 }
124 }
125 }