1 /*
2 * reserved comment block
3 * DO NOT REMOVE OR ALTER!
4 */
5 /*
6 * Copyright 2001-2004 The Apache Software Foundation.
7 *
8 * Licensed under the Apache License, Version 2.0 (the "License");
9 * you may not use this file except in compliance with the License.
10 * 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 * $Id: EqualityExpr.java,v 1.2.4.1 2005/09/12 10:16:52 pvedula Exp $
22 */
23
24 package com.sun.org.apache.xalan.internal.xsltc.compiler;
25
26 import com.sun.org.apache.bcel.internal.generic.BranchHandle;
27 import com.sun.org.apache.bcel.internal.generic.BranchInstruction;
28 import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
29 import com.sun.org.apache.bcel.internal.generic.GOTO;
30 import com.sun.org.apache.bcel.internal.generic.IFEQ;
31 import com.sun.org.apache.bcel.internal.generic.IFNE;
32 import com.sun.org.apache.bcel.internal.generic.IF_ICMPEQ;
33 import com.sun.org.apache.bcel.internal.generic.IF_ICMPNE;
34 import com.sun.org.apache.bcel.internal.generic.INVOKESTATIC;
35 import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
36 import com.sun.org.apache.bcel.internal.generic.InstructionList;
37 import com.sun.org.apache.bcel.internal.generic.PUSH;
38 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType;
39 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
40 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.IntType;
41 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
42 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType;
43 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;
44 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NumberType;
45 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.RealType;
46 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
47 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ResultTreeType;
48 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.StringType;
49 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
50 import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
51 import com.sun.org.apache.xalan.internal.xsltc.runtime.Operators;
52
53 /**
54 * @author Jacek Ambroziak
55 * @author Santiago Pericas-Geertsen
56 * @author Morten Jorgensen
57 * @author Erwin Bolwidt <ejb@klomp.org>
58 */
59 final class EqualityExpr extends Expression {
60
61 private final int _op;
62 private Expression _left;
63 private Expression _right;
64
65 public EqualityExpr(int op, Expression left, Expression right) {
66 _op = op;
67 (_left = left).setParent(this);
68 (_right = right).setParent(this);
69 }
70
71 public void setParser(Parser parser) {
72 super.setParser(parser);
73 _left.setParser(parser);
74 _right.setParser(parser);
75 }
76
77 public String toString() {
78 return Operators.getOpNames(_op) + '(' + _left + ", " + _right + ')';
79 }
80
81 public Expression getLeft() {
82 return _left;
83 }
84
85 public Expression getRight() {
86 return _right;
87 }
88
89 public boolean getOp() {
90 return (_op != Operators.NE);
91 }
92
93 /**
94 * Returns true if this expressions contains a call to position(). This is
95 * needed for context changes in node steps containing multiple predicates.
96 */
97 public boolean hasPositionCall() {
98 if (_left.hasPositionCall()) return true;
99 if (_right.hasPositionCall()) return true;
100 return false;
101 }
102
103 public boolean hasLastCall() {
104 if (_left.hasLastCall()) return true;
105 if (_right.hasLastCall()) return true;
106 return false;
107 }
108
109 private void swapArguments() {
110 final Expression temp = _left;
111 _left = _right;
112 _right = temp;
113 }
114
115 /**
116 * Typing rules: see XSLT Reference by M. Kay page 345.
117 */
118 public Type typeCheck(SymbolTable stable) throws TypeCheckError {
119 final Type tleft = _left.typeCheck(stable);
120 final Type tright = _right.typeCheck(stable);
121
122 if (tleft.isSimple() && tright.isSimple()) {
123 if (tleft != tright) {
124 if (tleft instanceof BooleanType) {
125 _right = new CastExpr(_right, Type.Boolean);
126 }
127 else if (tright instanceof BooleanType) {
128 _left = new CastExpr(_left, Type.Boolean);
129 }
130 else if (tleft instanceof NumberType ||
131 tright instanceof NumberType) {
132 _left = new CastExpr(_left, Type.Real);
133 _right = new CastExpr(_right, Type.Real);
134 }
135 else { // both compared as strings
136 _left = new CastExpr(_left, Type.String);
137 _right = new CastExpr(_right, Type.String);
138 }
139 }
140 }
141 else if (tleft instanceof ReferenceType) {
142 _right = new CastExpr(_right, Type.Reference);
143 }
144 else if (tright instanceof ReferenceType) {
145 _left = new CastExpr(_left, Type.Reference);
146 }
147 // the following 2 cases optimize @attr|.|.. = 'string'
148 else if (tleft instanceof NodeType && tright == Type.String) {
149 _left = new CastExpr(_left, Type.String);
150 }
151 else if (tleft == Type.String && tright instanceof NodeType) {
152 _right = new CastExpr(_right, Type.String);
153 }
154 // optimize node/node
155 else if (tleft instanceof NodeType && tright instanceof NodeType) {
156 _left = new CastExpr(_left, Type.String);
157 _right = new CastExpr(_right, Type.String);
158 }
159 else if (tleft instanceof NodeType && tright instanceof NodeSetType) {
160 // compare(Node, NodeSet) will be invoked
161 }
162 else if (tleft instanceof NodeSetType && tright instanceof NodeType) {
163 swapArguments(); // for compare(Node, NodeSet)
164 }
165 else {
166 // At least one argument is of type node, node-set or result-tree
167
168 // Promote an expression of type node to node-set
169 if (tleft instanceof NodeType) {
170 _left = new CastExpr(_left, Type.NodeSet);
171 }
172 if (tright instanceof NodeType) {
173 _right = new CastExpr(_right, Type.NodeSet);
174 }
175
176 // If one arg is a node-set then make it the left one
177 if (tleft.isSimple() ||
178 tleft instanceof ResultTreeType &&
179 tright instanceof NodeSetType) {
180 swapArguments();
181 }
182
183 // Promote integers to doubles to have fewer compares
184 if (_right.getType() instanceof IntType) {
185 _right = new CastExpr(_right, Type.Real);
186 }
187 }
188 return _type = Type.Boolean;
189 }
190
191 public void translateDesynthesized(ClassGenerator classGen,
192 MethodGenerator methodGen) {
193 final Type tleft = _left.getType();
194 final InstructionList il = methodGen.getInstructionList();
195
196 if (tleft instanceof BooleanType) {
197 _left.translate(classGen, methodGen);
198 _right.translate(classGen, methodGen);
199 _falseList.add(il.append(_op == Operators.EQ ?
200 (BranchInstruction)new IF_ICMPNE(null) :
201 (BranchInstruction)new IF_ICMPEQ(null)));
202 }
203 else if (tleft instanceof NumberType) {
204 _left.translate(classGen, methodGen);
205 _right.translate(classGen, methodGen);
206
207 if (tleft instanceof RealType) {
208 il.append(DCMPG);
209 _falseList.add(il.append(_op == Operators.EQ ?
210 (BranchInstruction)new IFNE(null) :
211 (BranchInstruction)new IFEQ(null)));
212 }
213 else {
214 _falseList.add(il.append(_op == Operators.EQ ?
215 (BranchInstruction)new IF_ICMPNE(null) :
216 (BranchInstruction)new IF_ICMPEQ(null)));
217 }
218 }
219 else {
220 translate(classGen, methodGen);
221 desynthesize(classGen, methodGen);
222 }
223 }
224
225 public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
226 final ConstantPoolGen cpg = classGen.getConstantPool();
227 final InstructionList il = methodGen.getInstructionList();
228
229 final Type tleft = _left.getType();
230 Type tright = _right.getType();
231
232 if (tleft instanceof BooleanType || tleft instanceof NumberType) {
233 translateDesynthesized(classGen, methodGen);
234 synthesize(classGen, methodGen);
235 return;
236 }
237
238 if (tleft instanceof StringType) {
239 final int equals = cpg.addMethodref(STRING_CLASS,
240 "equals",
241 "(" + OBJECT_SIG +")Z");
242 _left.translate(classGen, methodGen);
243 _right.translate(classGen, methodGen);
244 il.append(new INVOKEVIRTUAL(equals));
245
246 if (_op == Operators.NE) {
247 il.append(ICONST_1);
248 il.append(IXOR); // not x <-> x xor 1
249 }
250 return;
251 }
252
253 BranchHandle truec, falsec;
254
255 if (tleft instanceof ResultTreeType) {
256 if (tright instanceof BooleanType) {
257 _right.translate(classGen, methodGen);
258 if (_op == Operators.NE) {
259 il.append(ICONST_1);
260 il.append(IXOR); // not x <-> x xor 1
261 }
262 return;
263 }
264
265 if (tright instanceof RealType) {
266 _left.translate(classGen, methodGen);
267 tleft.translateTo(classGen, methodGen, Type.Real);
268 _right.translate(classGen, methodGen);
269
270 il.append(DCMPG);
271 falsec = il.append(_op == Operators.EQ ?
272 (BranchInstruction) new IFNE(null) :
273 (BranchInstruction) new IFEQ(null));
274 il.append(ICONST_1);
275 truec = il.append(new GOTO(null));
276 falsec.setTarget(il.append(ICONST_0));
277 truec.setTarget(il.append(NOP));
278 return;
279 }
280
281 // Next, result-tree/string and result-tree/result-tree comparisons
282
283 _left.translate(classGen, methodGen);
284 tleft.translateTo(classGen, methodGen, Type.String);
285 _right.translate(classGen, methodGen);
286
287 if (tright instanceof ResultTreeType) {
288 tright.translateTo(classGen, methodGen, Type.String);
289 }
290
291 final int equals = cpg.addMethodref(STRING_CLASS,
292 "equals",
293 "(" +OBJECT_SIG+ ")Z");
294 il.append(new INVOKEVIRTUAL(equals));
295
296 if (_op == Operators.NE) {
297 il.append(ICONST_1);
298 il.append(IXOR); // not x <-> x xor 1
299 }
300 return;
301 }
302
303 if (tleft instanceof NodeSetType && tright instanceof BooleanType) {
304 _left.translate(classGen, methodGen);
305 _left.startIterator(classGen, methodGen);
306 Type.NodeSet.translateTo(classGen, methodGen, Type.Boolean);
307 _right.translate(classGen, methodGen);
308
309 il.append(IXOR); // x != y <-> x xor y
310 if (_op == Operators.EQ) {
311 il.append(ICONST_1);
312 il.append(IXOR); // not x <-> x xor 1
313 }
314 return;
315 }
316
317 if (tleft instanceof NodeSetType && tright instanceof StringType) {
318 _left.translate(classGen, methodGen);
319 _left.startIterator(classGen, methodGen); // needed ?
320 _right.translate(classGen, methodGen);
321 il.append(new PUSH(cpg, _op));
322 il.append(methodGen.loadDOM());
323 final int cmp = cpg.addMethodref(BASIS_LIBRARY_CLASS,
324 "compare",
325 "("
326 + tleft.toSignature()
327 + tright.toSignature()
328 + "I"
329 + DOM_INTF_SIG
330 + ")Z");
331 il.append(new INVOKESTATIC(cmp));
332 return;
333 }
334
335 // Next, node-set/t for t in {real, string, node-set, result-tree}
336 _left.translate(classGen, methodGen);
337 _left.startIterator(classGen, methodGen);
338 _right.translate(classGen, methodGen);
339 _right.startIterator(classGen, methodGen);
340
341 // Cast a result tree to a string to use an existing compare
342 if (tright instanceof ResultTreeType) {
343 tright.translateTo(classGen, methodGen, Type.String);
344 tright = Type.String;
345 }
346
347 // Call the appropriate compare() from the BasisLibrary
348 il.append(new PUSH(cpg, _op));
349 il.append(methodGen.loadDOM());
350
351 final int compare = cpg.addMethodref(BASIS_LIBRARY_CLASS,
352 "compare",
353 "("
354 + tleft.toSignature()
355 + tright.toSignature()
356 + "I"
357 + DOM_INTF_SIG
358 + ")Z");
359 il.append(new INVOKESTATIC(compare));
360 }
361 }