1 /*
2 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
3 */
4 /*
5 * Licensed to the Apache Software Foundation (ASF) under one or more
6 * contributor license agreements. See the NOTICE file distributed with
7 * this work for additional information regarding copyright ownership.
8 * The ASF licenses this file to You under the Apache License, Version 2.0
9 * (the "License"); you may not use this file except in compliance with
10 * the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing, software
15 * distributed under the License is distributed on an "AS IS" BASIS,
16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17 * See the License for the specific language governing permissions and
18 * limitations under the License.
19 */
20
21 package com.sun.org.apache.xalan.internal.xsltc.compiler;
22
23 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
24 import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
25 import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
26 import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
27 import com.sun.org.apache.bcel.internal.generic.InstructionList;
28 import com.sun.org.apache.bcel.internal.generic.NEW;
29 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
30 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
31 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
32 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
33 import com.sun.org.apache.xml.internal.dtm.Axis;
34 import com.sun.org.apache.xml.internal.dtm.DTM;
35 import java.util.ArrayList;
36 import java.util.List;
37
38 /**
39 * @author Jacek Ambroziak
40 * @author Santiago Pericas-Geertsen
41 * @LastModified: Nov 2017
42 */
43 final class UnionPathExpr extends Expression {
44
45 private final Expression _pathExpr;
46 private final Expression _rest;
47 private boolean _reverse = false;
48
49 // linearization for top level UnionPathExprs
50 private Expression[] _components;
51
52 public UnionPathExpr(Expression pathExpr, Expression rest) {
53 _pathExpr = pathExpr;
54 _rest = rest;
55 }
56
57 public void setParser(Parser parser) {
58 super.setParser(parser);
59 // find all expressions in this Union
60 final List<Expression> components = new ArrayList<>();
61 flatten(components);
62 final int size = components.size();
63 _components = components.toArray(new Expression[size]);
64 for (int i = 0; i < size; i++) {
65 _components[i].setParser(parser);
66 _components[i].setParent(this);
67 if (_components[i] instanceof Step) {
68 final Step step = (Step)_components[i];
69 final int axis = step.getAxis();
70 final int type = step.getNodeType();
71 // Put attribute iterators first
72 if ((axis == Axis.ATTRIBUTE) || (type == DTM.ATTRIBUTE_NODE)) {
73 _components[i] = _components[0];
74 _components[0] = step;
75 }
76 // Check if the union contains a reverse iterator
77 if (Axis.isReverse(axis)) _reverse = true;
78 }
79 }
80 // No need to reverse anything if another expression lies on top of this
81 if (getParent() instanceof Expression) _reverse = false;
82 }
83
84 public Type typeCheck(SymbolTable stable) throws TypeCheckError {
85 final int length = _components.length;
86 for (int i = 0; i < length; i++) {
87 if (_components[i].typeCheck(stable) != Type.NodeSet) {
88 _components[i] = new CastExpr(_components[i], Type.NodeSet);
89 }
90 }
91 return _type = Type.NodeSet;
92 }
93
94 public String toString() {
95 return "union(" + _pathExpr + ", " + _rest + ')';
96 }
97
98 private void flatten(List<Expression> components) {
99 components.add(_pathExpr);
100 if (_rest != null) {
101 if (_rest instanceof UnionPathExpr) {
102 ((UnionPathExpr)_rest).flatten(components);
103 }
104 else {
105 components.add(_rest);
106 }
107 }
108 }
109
110 public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
111 final ConstantPoolGen cpg = classGen.getConstantPool();
112 final InstructionList il = methodGen.getInstructionList();
113
114 final int init = cpg.addMethodref(UNION_ITERATOR_CLASS,
115 "<init>",
116 "("+DOM_INTF_SIG+")V");
117 final int iter = cpg.addMethodref(UNION_ITERATOR_CLASS,
118 ADD_ITERATOR,
119 ADD_ITERATOR_SIG);
120
121 // Create the UnionIterator and leave it on the stack
122 il.append(new NEW(cpg.addClass(UNION_ITERATOR_CLASS)));
123 il.append(DUP);
124 il.append(methodGen.loadDOM());
125 il.append(new INVOKESPECIAL(init));
126
127 // Add the various iterators to the UnionIterator
128 final int length = _components.length;
129 for (int i = 0; i < length; i++) {
130 _components[i].translate(classGen, methodGen);
131 il.append(new INVOKEVIRTUAL(iter));
132 }
133
134 // Order the iterator only if strictly needed
135 if (_reverse) {
136 final int order = cpg.addInterfaceMethodref(DOM_INTF,
137 ORDER_ITERATOR,
138 ORDER_ITERATOR_SIG);
139 il.append(methodGen.loadDOM());
140 il.append(SWAP);
141 il.append(methodGen.loadContextNode());
142 il.append(new INVOKEINTERFACE(order, 3));
143
144 }
145 }
146 }