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1
19
20 package edu.umd.cs.findbugs.detect;
21
22 import java.util.HashMap  ;
23 import java.util.HashSet ;
24 import java.util.Map ;
25
26 import edu.umd.cs.findbugs.*;
27 import edu.umd.cs.findbugs.ba.AnalysisContext;
28
29 import org.apache.bcel.Repository;
30 import org.apache.bcel.classfile.*;
31
32 public class FindHEmismatch extends BytecodeScanningDetector implements
33 StatelessDetector {
34 boolean hasFields = false;
35
36 boolean visibleOutsidePackage = false;
37
38 boolean hasHashCode = false;
39
40 boolean hasEqualsObject = false;
41
42 boolean hashCodeIsAbstract = false;
43
44 boolean equalsObjectIsAbstract = false;
45
46 boolean equalsMethodIsInstanceOfEquals = false;
47
48 boolean hasCompareToObject = false;
49
50 boolean hasEqualsSelf = false;
51
52 boolean hasCompareToSelf = false;
53
54 boolean extendsObject = false;
55
56 MethodAnnotation equalsMethod = null;
57
58 MethodAnnotation compareToMethod = null;
59 MethodAnnotation compareToObjectMethod = null;
60 MethodAnnotation compareToSelfMethod = null;
61
62 MethodAnnotation hashCodeMethod = null;
63
64 HashSet <String > nonHashableClasses = new HashSet <String >();
65 OpcodeStack stack = new OpcodeStack();
66
67 public boolean isHashableClassName(String dottedClassName) {
68 return !nonHashableClasses.contains(dottedClassName);
69 }
70 Map <String , BugInstance> potentialBugs = new HashMap <String , BugInstance>();
71
72 private BugReporter bugReporter;
73
74 public FindHEmismatch(BugReporter bugReporter) {
75 this.bugReporter = bugReporter;
76 }
77
78 @Override
79 public void visitAfter(JavaClass obj) {
80 if (!obj.isClass())
81 return;
82 if (getDottedClassName().equals("java.lang.Object"))
83 return;
84 int accessFlags = obj.getAccessFlags();
85 if ((accessFlags & ACC_INTERFACE) != 0)
86 return;
87 visibleOutsidePackage = obj.isPublic() || obj.isProtected();
88
89 String whereEqual = getDottedClassName();
90 boolean classThatDefinesEqualsIsAbstract = false;
91 boolean classThatDefinesHashCodeIsAbstract = false;
92 boolean inheritedHashCodeIsFinal = false;
93 boolean inheritedEqualsIsFinal = false;
94 boolean inheritedEqualsIsAbstract = false;
95 if (!hasEqualsObject) {
96 JavaClass we = Lookup.findSuperImplementor(obj, "equals",
97 "(Ljava/lang/Object;)Z", bugReporter);
98 if (we == null) {
99 whereEqual = "java.lang.Object";
100 } else {
101 whereEqual = we.getClassName();
102 classThatDefinesEqualsIsAbstract = we.isAbstract();
103 Method m = findMethod(we, "equals", "(Ljava/lang/Object;)Z");
104 if (m != null && m.isFinal())
105 inheritedEqualsIsFinal = true;
106 if (m != null && m.isAbstract())
107 inheritedEqualsIsAbstract = true;
108 }
109 }
110 boolean usesDefaultEquals = whereEqual.equals("java.lang.Object");
111 String whereHashCode = getDottedClassName();
112 if (!hasHashCode) {
113 JavaClass wh = Lookup.findSuperImplementor(obj, "hashCode", "()I",
114 bugReporter);
115 if (wh == null) {
116 whereHashCode = "java.lang.Object";
117 } else {
118 whereHashCode = wh.getClassName();
119 classThatDefinesHashCodeIsAbstract = wh.isAbstract();
120 Method m = findMethod(wh, "hashCode", "()I");
121 if (m != null && m.isFinal())
122 inheritedHashCodeIsFinal = true;
123 }
124 }
125 boolean usesDefaultHashCode = whereHashCode.equals("java.lang.Object");
126 if (false && (usesDefaultEquals || usesDefaultHashCode)) {
127 try {
128 if (Repository.implementationOf(obj, "java/util/Set")
129 || Repository.implementationOf(obj, "java/util/List")
130 || Repository.implementationOf(obj, "java/util/Map")) {
131 }
134 } catch (ClassNotFoundException e) {
135 }
137 }
138
139 if (!hasEqualsObject && hasEqualsSelf) {
140
141 if (usesDefaultEquals) {
142 int priority = HIGH_PRIORITY;
143 if (usesDefaultHashCode || obj.isAbstract())
144 priority++;
145 if (!visibleOutsidePackage)
146 priority++;
147 BugInstance bug = new BugInstance(this, "EQ_SELF_USE_OBJECT",
148 priority).addClass(getDottedClassName());
149 if (equalsMethod != null)
150 bug.addMethod(equalsMethod);
151 bugReporter.reportBug(bug);
152 } else {
153 int priority = NORMAL_PRIORITY;
154 if (hasFields)
155 priority--;
156 if (obj.isAbstract())
157 priority++;
158 BugInstance bug = new BugInstance(this, "EQ_SELF_NO_OBJECT",
159 priority).addClass(getDottedClassName());
160 if (equalsMethod != null)
161 bug.addMethod(equalsMethod);
162 bugReporter.reportBug(bug);
163 }
164 }
165
166
174
175 if ((hasCompareToObject || hasCompareToSelf) && usesDefaultEquals) {
176 BugInstance bug = new BugInstance(this, "EQ_COMPARETO_USE_OBJECT_EQUALS",
177 obj.isAbstract() ? Priorities.LOW_PRIORITY : Priorities.NORMAL_PRIORITY).addClass(this);
178 if (compareToSelfMethod != null) bug.addMethod(compareToSelfMethod);
179 else bug.addMethod(compareToObjectMethod);
180 bugReporter.reportBug(bug);
181 }
182 if (!hasCompareToObject && hasCompareToSelf) {
183 if (!extendsObject)
184 bugReporter.reportBug(new BugInstance(this,
185 "CO_SELF_NO_OBJECT", NORMAL_PRIORITY).addClass(
186 getDottedClassName()).addMethod(compareToMethod));
187 }
188
189 if (hasHashCode && !hashCodeIsAbstract
191 && !(hasEqualsObject || hasEqualsSelf)) {
192 int priority = LOW_PRIORITY;
193 if (usesDefaultEquals)
194 bugReporter.reportBug(new BugInstance(this,
195 "HE_HASHCODE_USE_OBJECT_EQUALS", priority).addClass(
196 getDottedClassName()).addMethod(hashCodeMethod));
197 else if (!inheritedEqualsIsFinal)
198 bugReporter.reportBug(new BugInstance(this,
199 "HE_HASHCODE_NO_EQUALS", priority).addClass(
200 getDottedClassName()).addMethod(hashCodeMethod));
201 }
202 if (!hasHashCode
203 && (hasEqualsObject && !equalsObjectIsAbstract || hasEqualsSelf)) {
204 if (usesDefaultHashCode) {
205 int priority = HIGH_PRIORITY;
206 if (equalsMethodIsInstanceOfEquals)
207 priority += 2;
208 else if (obj.isAbstract() || !hasEqualsObject)
209 priority++;
210 if (priority == HIGH_PRIORITY)
211 nonHashableClasses.add(getDottedClassName());
212 if (!visibleOutsidePackage) {
213 priority++;
214 }
215 BugInstance bug = new BugInstance(this,
216 "HE_EQUALS_USE_HASHCODE", priority)
217 .addClass(getDottedClassName());
218 if (equalsMethod != null)
219 bug.addMethod(equalsMethod);
220 bugReporter.reportBug(bug);
221 } else if (!inheritedHashCodeIsFinal
222 && !whereHashCode.startsWith("java.util.Abstract")) {
223 int priority = LOW_PRIORITY;
224
225 if (hasEqualsObject && inheritedEqualsIsAbstract)
226 priority++;
227 if (hasFields)
228 priority--;
229 if (equalsMethodIsInstanceOfEquals || !hasEqualsObject)
230 priority += 2;
231 else if (obj.isAbstract())
232 priority++;
233 BugInstance bug = new BugInstance(this,
234 "HE_EQUALS_NO_HASHCODE", priority)
235 .addClass(getDottedClassName());
236 if (equalsMethod != null)
237 bug.addMethod(equalsMethod);
238 bugReporter.reportBug(bug);
239 }
240 }
241 if (!hasHashCode && !hasEqualsObject && !hasEqualsSelf
242 && !usesDefaultEquals && usesDefaultHashCode
243 && !obj.isAbstract() && classThatDefinesEqualsIsAbstract) {
244 BugInstance bug = new BugInstance(this,
245 "HE_INHERITS_EQUALS_USE_HASHCODE", NORMAL_PRIORITY)
246 .addClass(getDottedClassName());
247 if (equalsMethod != null)
248 bug.addMethod(equalsMethod);
249 bugReporter.reportBug(bug);
250 }
251 }
252
253 @Override
254 public void visit(JavaClass obj) {
255 extendsObject = getDottedSuperclassName().equals("java.lang.Object");
256 hasFields = false;
257 hasHashCode = false;
258 hasCompareToObject = false;
259 hasCompareToSelf = false;
260 hasEqualsObject = false;
261 hasEqualsSelf = false;
262 hashCodeIsAbstract = false;
263 equalsObjectIsAbstract = false;
264 equalsMethodIsInstanceOfEquals = false;
265 equalsMethod = null;
266 compareToMethod = null;
267 compareToSelfMethod = null;
268 compareToObjectMethod = null;
269 hashCodeMethod = null;
270 }
271
272 @Override
273 public void visit(Field obj) {
274 int accessFlags = obj.getAccessFlags();
275 if ((accessFlags & ACC_STATIC) != 0)
276 return;
277 if (!obj.getName().startsWith("this$"))
278 hasFields = true;
279 }
280
281 @Override
282 public void visit(Method obj) {
283 stack.resetForMethodEntry(this);
284
285 int accessFlags = obj.getAccessFlags();
286 if ((accessFlags & ACC_STATIC) != 0)
287 return;
288 String name = obj.getName();
289 String sig = obj.getSignature();
290 if ((accessFlags & ACC_ABSTRACT) != 0) {
291 if (name.equals("equals")
292 && sig.equals("(L" + getClassName() + ";)Z")) {
293 bugReporter.reportBug(new BugInstance(this, "EQ_ABSTRACT_SELF",
294 LOW_PRIORITY).addClass(getDottedClassName()));
295 return;
296 } else if (name.equals("compareTo")
297 && sig.equals("(L" + getClassName() + ";)I")) {
298 bugReporter.reportBug(new BugInstance(this, "CO_ABSTRACT_SELF",
299 LOW_PRIORITY).addClass(getDottedClassName()));
300 return;
301 }
302 }
303 boolean sigIsObject = sig.equals("(Ljava/lang/Object;)Z");
304 if (name.equals("hashCode") && sig.equals("()I")) {
305 hasHashCode = true;
306 if (obj.isAbstract())
307 hashCodeIsAbstract = true;
308 hashCodeMethod = MethodAnnotation.fromVisitedMethod(this);
309 } else if (name.equals("equals")) {
311 if (sigIsObject) {
312 equalsMethod = MethodAnnotation.fromVisitedMethod(this);
313 hasEqualsObject = true;
314 if (obj.isAbstract())
315 equalsObjectIsAbstract = true;
316 else if (!obj.isNative()) {
317 Code code = obj.getCode();
318 byte[] codeBytes = code.getCode();
319
320 if ((codeBytes.length == 5 && (codeBytes[1] & 0xff) == INSTANCEOF)
321 || (codeBytes.length == 15
322 && (codeBytes[1] & 0xff) == INSTANCEOF && (codeBytes[11] & 0xff) == INVOKESPECIAL)) {
323 equalsMethodIsInstanceOfEquals = true;
324 }
325 }
326 } else if (sig.equals("(L" + getClassName() + ";)Z")) {
327 hasEqualsSelf = true;
328 if (equalsMethod == null)
329 equalsMethod = MethodAnnotation.fromVisitedMethod(this);
330 }
331 } else if (name.equals("compareTo")) {
332 MethodAnnotation tmp = MethodAnnotation.fromVisitedMethod(this);
333 if (sig.equals("(Ljava/lang/Object;)I")) {
334 hasCompareToObject = true;
335 compareToObjectMethod = compareToMethod = tmp;
336 }
337 else if (sig.equals("(L" + getClassName() + ";)I")) {
338 hasCompareToSelf = true;
339 compareToSelfMethod = compareToMethod = tmp;
340 }
341 }
342 }
343
344 Method findMethod(JavaClass clazz, String name, String sig) {
345 Method[] m = clazz.getMethods();
346 for (Method aM : m)
347 if (aM.getName().equals(name) && aM.getSignature().equals(sig))
348 return aM;
349 return null;
350 }
351
352
353 @Override
354 public void sawOpcode(int seen) {
355 stack.mergeJumps(this);
356 if (seen == INVOKEVIRTUAL) {
357 String className = getClassConstantOperand();
358 if (className.equals("java/util/Map") || className.equals("java/util/HashMap")
359 || className.equals("java/util/LinkedHashMap")
360 || className.equals("java/util/concurrent/ConcurrentHashMap") ) {
361 if (getNameConstantOperand().equals("put")
362 && getSigConstantOperand()
363 .equals("(Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;")
364 && stack.getStackDepth() >= 3) check(1);
365 else if ((getNameConstantOperand().equals("get") || getNameConstantOperand().equals("remove"))
366 && getSigConstantOperand()
367 .equals("(Ljava/lang/Object;)Ljava/lang/Object;")
368 && stack.getStackDepth() >= 2) check(0);
369 } else if (className.equals("java/util/Set") || className.equals("java/util/HashSet") ) {
370 if (getNameConstantOperand().equals("add") || getNameConstantOperand().equals("contains") || getNameConstantOperand().equals("remove")
371 && getSigConstantOperand()
372 .equals("(Ljava/lang/Object;)Z")
373 && stack.getStackDepth() >= 2) check(0);
374 }
375 }
376 stack.sawOpcode(this, seen);
377 }
378 private void check(int pos) {
379 OpcodeStack.Item item = stack.getStackItem(pos);
380 JavaClass type = null;
381
382 try {
383 type = item.getJavaClass();
384 } catch (ClassNotFoundException e) {
385 AnalysisContext.reportMissingClass(e);
386 }
387 if (type == null) return;
388 if (!AnalysisContext.currentAnalysisContext().getSubtypes().isApplicationClass(type)) return;
389 int priority = NORMAL_PRIORITY;
390 if (getClassConstantOperand().indexOf("Hash") >= 0) priority--;
391 if (type.isAbstract() || type.isInterface()) priority++;
392 potentialBugs.put(type.getClassName(),
393 new BugInstance("HE_USE_OF_UNHASHABLE_CLASS",priority)
394 .addClassAndMethod(this)
395 .addTypeOfNamedClass(type.getClassName())
396 .addTypeOfNamedClass(getClassConstantOperand())
397 .addSourceLine(this));
398 }
399
400 @Override
401 public void report() {
402 for(Map.Entry <String , BugInstance> e : potentialBugs.entrySet()) {
403 if (!isHashableClassName(e.getKey()))
404 bugReporter.reportBug(e.getValue());
405 }
406
407 }
408 }
409 |
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