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.BranchHandle;
25 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
26 import com.sun.org.apache.bcel.internal.generic.GOTO;
27 import com.sun.org.apache.bcel.internal.generic.IFLT;
28 import com.sun.org.apache.bcel.internal.generic.ILOAD;
29 import com.sun.org.apache.bcel.internal.generic.INVOKEINTERFACE;
30 import com.sun.org.apache.bcel.internal.generic.ISTORE;
31 import com.sun.org.apache.bcel.internal.generic.InstructionHandle;
32 import com.sun.org.apache.bcel.internal.generic.InstructionList;
33 import com.sun.org.apache.bcel.internal.generic.LocalVariableGen;
34 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
35 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
36 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
37 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
38 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Util;
39
40 /**
41 * @author Jacek Ambroziak
42 * @author Santiago Pericas-Geertsen
43 * @author Erwin Bolwidt <ejb@klomp.org>
44 */
45 final class AncestorPattern extends RelativePathPattern {
46
47 private final Pattern _left; // may be null
48 private final RelativePathPattern _right;
49 private InstructionHandle _loop;
50
51 public AncestorPattern(RelativePathPattern right) {
52 this(null, right);
53 }
54
55 public AncestorPattern(Pattern left, RelativePathPattern right) {
56 _left = left;
57 (_right = right).setParent(this);
58 if (left != null) {
59 left.setParent(this);
60 }
61 }
62
63 public InstructionHandle getLoopHandle() {
64 return _loop;
65 }
66
67 public void setParser(Parser parser) {
68 super.setParser(parser);
69 if (_left != null) {
70 _left.setParser(parser);
71 }
72 _right.setParser(parser);
73 }
74
75 public boolean isWildcard() {
76 //!!! can be wildcard
77 return false;
78 }
79
80 public StepPattern getKernelPattern() {
81 return _right.getKernelPattern();
82 }
83
84 public void reduceKernelPattern() {
85 _right.reduceKernelPattern();
86 }
87
88 public Type typeCheck(SymbolTable stable) throws TypeCheckError {
89 if (_left != null) {
90 _left.typeCheck(stable);
91 }
92 return _right.typeCheck(stable);
93 }
94
95 public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
96 InstructionHandle parent;
97 final ConstantPoolGen cpg = classGen.getConstantPool();
98 final InstructionList il = methodGen.getInstructionList();
99
100 /*
101 * The scope of this local var must be the entire method since
102 * a another pattern may decide to jump back into the loop
103 */
104 final LocalVariableGen local =
105 methodGen.addLocalVariable2("app", Util.getJCRefType(NODE_SIG),
106 il.getEnd());
107
108 final com.sun.org.apache.bcel.internal.generic.Instruction loadLocal =
109 new ILOAD(local.getIndex());
110 final com.sun.org.apache.bcel.internal.generic.Instruction storeLocal =
111 new ISTORE(local.getIndex());
112
113 if (_right instanceof StepPattern) {
114 il.append(DUP);
115 il.append(storeLocal);
116 _right.translate(classGen, methodGen);
117 il.append(methodGen.loadDOM());
118 il.append(loadLocal);
119 }
120 else {
121 _right.translate(classGen, methodGen);
122
123 if (_right instanceof AncestorPattern) {
124 il.append(methodGen.loadDOM());
125 il.append(SWAP);
126 }
127 }
128
129 if (_left != null) {
130 final int getParent = cpg.addInterfaceMethodref(DOM_INTF,
131 GET_PARENT,
132 GET_PARENT_SIG);
133 parent = il.append(new INVOKEINTERFACE(getParent, 2));
134
135 il.append(DUP);
136 il.append(storeLocal);
137 _falseList.add(il.append(new IFLT(null)));
138 il.append(loadLocal);
139
140 _left.translate(classGen, methodGen);
141
142 final SyntaxTreeNode p = getParent();
143 if (p == null || p instanceof Instruction ||
144 p instanceof TopLevelElement)
145 {
146 // do nothing
147 }
148 else {
149 il.append(loadLocal);
150 }
151
152 final BranchHandle exit = il.append(new GOTO(null));
153 _loop = il.append(methodGen.loadDOM());
154 il.append(loadLocal);
155 local.setEnd(_loop);
156 il.append(new GOTO(parent));
157 exit.setTarget(il.append(NOP));
158 _left.backPatchFalseList(_loop);
159
160 _trueList.append(_left._trueList);
161 }
162 else {
163 il.append(POP2);
164 }
165
166 /*
167 * If _right is an ancestor pattern, backpatch this pattern's false
168 * list to the loop that searches for more ancestors.
169 */
170 if (_right instanceof AncestorPattern) {
171 final AncestorPattern ancestor = (AncestorPattern) _right;
172 _falseList.backPatch(ancestor.getLoopHandle()); // clears list
173 }
174
175 _trueList.append(_right._trueList);
176 _falseList.append(_right._falseList);
177 }
178
179 public String toString() {
180 return "AncestorPattern(" + _left + ", " + _right + ')';
181 }
182 }