1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Licensed to the Apache Software Foundation (ASF) under one or more
7 * contributor license agreements. See the NOTICE file distributed with
8 * this work for additional information regarding copyright ownership.
9 * The ASF licenses this file to You under the Apache License, Version 2.0
10 * (the "License"); you may not use this file except in compliance with
11 * the License. You may obtain a copy of the License at
12 *
13 * http://www.apache.org/licenses/LICENSE-2.0
14 *
15 * Unless required by applicable law or agreed to in writing, software
16 * distributed under the License is distributed on an "AS IS" BASIS,
17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
18 * See the License for the specific language governing permissions and
19 * limitations under the License.
20 */
21
22 package com.sun.org.apache.xalan.internal.xsltc.compiler;
23
24 import com.sun.org.apache.bcel.internal.generic.ALOAD;
25 import com.sun.org.apache.bcel.internal.generic.ASTORE;
26 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
27 import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
28 import com.sun.org.apache.bcel.internal.generic.INVOKESPECIAL;
29 import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
30 import com.sun.org.apache.bcel.internal.generic.InstructionList;
31 import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
32 import com.sun.org.apache.bcel.internal.generic.NEW;
33 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
34 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
35 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType;
36 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;
37 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
38 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
39 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
40 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
41
42 /**
43 * @author Jacek Ambroziak
44 * @author Santiago Pericas-Geertsen
45 */
46 final class FilterParentPath extends Expression {
47
48 private Expression _filterExpr;
49 private Expression _path;
50 private boolean _hasDescendantAxis = false;
51
52 public FilterParentPath(Expression filterExpr, Expression path) {
53 (_path = path).setParent(this);
54 (_filterExpr = filterExpr).setParent(this);
55 }
56
57 public void setParser(Parser parser) {
58 super.setParser(parser);
59 _filterExpr.setParser(parser);
60 _path.setParser(parser);
61 }
62
63 public String toString() {
64 return "FilterParentPath(" + _filterExpr + ", " + _path + ')';
65 }
66
67 public void setDescendantAxis() {
68 _hasDescendantAxis = true;
69 }
70
71 /**
72 * Type check a FilterParentPath. If the filter is not a node-set add a
73 * cast to node-set only if it is of reference type. This type coercion is
74 * needed for expressions like $x/LINE where $x is a parameter reference.
75 */
76 public Type typeCheck(SymbolTable stable) throws TypeCheckError {
77 final Type ftype = _filterExpr.typeCheck(stable);
78 if (ftype instanceof NodeSetType == false) {
79 if (ftype instanceof ReferenceType) {
80 _filterExpr = new CastExpr(_filterExpr, Type.NodeSet);
81 }
82 /*
83 else if (ftype instanceof ResultTreeType) {
84 _filterExpr = new CastExpr(_filterExpr, Type.NodeSet);
85 }
86 */
87 else if (ftype instanceof NodeType) {
88 _filterExpr = new CastExpr(_filterExpr, Type.NodeSet);
89 }
90 else {
91 throw new TypeCheckError(this);
92 }
93 }
94
95 // Wrap single node path in a node set
96 final Type ptype = _path.typeCheck(stable);
97 if (!(ptype instanceof NodeSetType)) {
98 _path = new CastExpr(_path, Type.NodeSet);
99 }
100
101 return _type = Type.NodeSet;
102 }
103
104 public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
105 final ConstantPoolGen cpg = classGen.getConstantPool();
106 final InstructionList il = methodGen.getInstructionList();
107 // Create new StepIterator
108 final int initSI = cpg.addMethodref(STEP_ITERATOR_CLASS,
109 "<init>",
110 "("
111 +NODE_ITERATOR_SIG
112 +NODE_ITERATOR_SIG
113 +")V");
114
115 // Backwards branches are prohibited if an uninitialized object is
116 // on the stack by section 4.9.4 of the JVM Specification, 2nd Ed.
117 // We don't know whether this code might contain backwards branches,
118 // so we mustn't create the new object until after we've created
119 // the suspect arguments to its constructor. Instead we calculate
120 // the values of the arguments to the constructor first, store them
121 // in temporary variables, create the object and reload the
122 // arguments from the temporaries to avoid the problem.
123
124 // Recursively compile 2 iterators
125 _filterExpr.translate(classGen, methodGen);
126 LocalVariableGen filterTemp =
127 methodGen.addLocalVariable("filter_parent_path_tmp1",
128 Util.getJCRefType(NODE_ITERATOR_SIG),
129 null, null);
130 filterTemp.setStart(il.append(new ASTORE(filterTemp.getIndex())));
131
132 _path.translate(classGen, methodGen);
133 LocalVariableGen pathTemp =
134 methodGen.addLocalVariable("filter_parent_path_tmp2",
135 Util.getJCRefType(NODE_ITERATOR_SIG),
136 null, null);
137 pathTemp.setStart(il.append(new ASTORE(pathTemp.getIndex())));
138
139 il.append(new NEW(cpg.addClass(STEP_ITERATOR_CLASS)));
140 il.append(DUP);
141 filterTemp.setEnd(il.append(new ALOAD(filterTemp.getIndex())));
142 pathTemp.setEnd(il.append(new ALOAD(pathTemp.getIndex())));
143
144 // Initialize StepIterator with iterators from the stack
145 il.append(new INVOKESPECIAL(initSI));
146
147 // This is a special case for the //* path with or without predicates
148 if (_hasDescendantAxis) {
149 final int incl = cpg.addMethodref(NODE_ITERATOR_BASE,
150 "includeSelf",
151 "()" + NODE_ITERATOR_SIG);
152 il.append(new INVOKEVIRTUAL(incl));
153 }
154
155 SyntaxTreeNode parent = getParent();
156
157 boolean parentAlreadyOrdered =
158 (parent instanceof RelativeLocationPath)
159 || (parent instanceof FilterParentPath)
160 || (parent instanceof KeyCall)
161 || (parent instanceof CurrentCall)
162 || (parent instanceof DocumentCall);
163
164 if (!parentAlreadyOrdered) {
165 final int order = cpg.addInterfaceMethodref(DOM_INTF,
166 ORDER_ITERATOR,
167 ORDER_ITERATOR_SIG);
168 il.append(methodGen.loadDOM());
169 il.append(SWAP);
170 il.append(methodGen.loadContextNode());
171 il.append(new INVOKEINTERFACE(order, 3));
172 }
173 }
174 }