1
2
3
4 package net.sourceforge.pmd.lang.java.rule.basic;
5
6 import java.util.ArrayList;
7 import java.util.List;
8
9 import net.sourceforge.pmd.lang.ast.Node;
10 import net.sourceforge.pmd.lang.java.ast.ASTAssignmentOperator;
11 import net.sourceforge.pmd.lang.java.ast.ASTClassOrInterfaceDeclaration;
12 import net.sourceforge.pmd.lang.java.ast.ASTCompilationUnit;
13 import net.sourceforge.pmd.lang.java.ast.ASTEqualityExpression;
14 import net.sourceforge.pmd.lang.java.ast.ASTExpression;
15 import net.sourceforge.pmd.lang.java.ast.ASTFieldDeclaration;
16 import net.sourceforge.pmd.lang.java.ast.ASTIfStatement;
17 import net.sourceforge.pmd.lang.java.ast.ASTLiteral;
18 import net.sourceforge.pmd.lang.java.ast.ASTLocalVariableDeclaration;
19 import net.sourceforge.pmd.lang.java.ast.ASTMethodDeclaration;
20 import net.sourceforge.pmd.lang.java.ast.ASTName;
21 import net.sourceforge.pmd.lang.java.ast.ASTNullLiteral;
22 import net.sourceforge.pmd.lang.java.ast.ASTPrimaryExpression;
23 import net.sourceforge.pmd.lang.java.ast.ASTPrimaryPrefix;
24 import net.sourceforge.pmd.lang.java.ast.ASTReferenceType;
25 import net.sourceforge.pmd.lang.java.ast.ASTReturnStatement;
26 import net.sourceforge.pmd.lang.java.ast.ASTStatementExpression;
27 import net.sourceforge.pmd.lang.java.ast.ASTSynchronizedStatement;
28 import net.sourceforge.pmd.lang.java.ast.ASTType;
29 import net.sourceforge.pmd.lang.java.ast.ASTVariableDeclaratorId;
30 import net.sourceforge.pmd.lang.java.ast.ASTVariableInitializer;
31 import net.sourceforge.pmd.lang.java.rule.AbstractJavaRule;
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52 public class DoubleCheckedLockingRule extends AbstractJavaRule {
53
54 private List<String> volatileFields;
55
56 @Override
57 public Object visit(ASTClassOrInterfaceDeclaration node, Object data) {
58 if (node.isInterface()) {
59 return data;
60 }
61 return super.visit(node, data);
62 }
63
64 @Override
65 public Object visit(ASTCompilationUnit compilationUnit, Object data) {
66 if (this.volatileFields == null) {
67 this.volatileFields = new ArrayList<String>(0);
68 } else {
69 this.volatileFields.clear();
70 }
71 return super.visit(compilationUnit, data);
72 }
73
74 @Override
75 public Object visit(ASTFieldDeclaration fieldDeclaration, Object data) {
76 if (fieldDeclaration.isVolatile()) {
77 for (ASTVariableDeclaratorId declarator : fieldDeclaration
78 .findDescendantsOfType(ASTVariableDeclaratorId.class)) {
79 this.volatileFields.add(declarator.getImage());
80 }
81 }
82 return super.visit(fieldDeclaration, data);
83 }
84
85 @Override
86 public Object visit(ASTMethodDeclaration node, Object data) {
87 if (node.getResultType().isVoid()) {
88 return super.visit(node, data);
89 }
90
91 ASTType typeNode = (ASTType) node.getResultType().jjtGetChild(0);
92 if (typeNode.jjtGetNumChildren() == 0 || !(typeNode.jjtGetChild(0) instanceof ASTReferenceType)) {
93 return super.visit(node, data);
94 }
95
96 List<ASTReturnStatement> rsl = node.findDescendantsOfType(ASTReturnStatement.class);
97 if (rsl.size() != 1) {
98 return super.visit(node, data);
99 }
100 ASTReturnStatement rs = rsl.get(0);
101
102 List<ASTPrimaryExpression> pel = rs.findDescendantsOfType(ASTPrimaryExpression.class);
103 ASTPrimaryExpression ape = pel.get(0);
104 Node lastChild = ape.jjtGetChild(ape.jjtGetNumChildren() - 1);
105 String returnVariableName = null;
106 if (lastChild instanceof ASTPrimaryPrefix) {
107 returnVariableName = getNameFromPrimaryPrefix((ASTPrimaryPrefix) lastChild);
108 }
109
110 if (returnVariableName == null || this.volatileFields.contains(returnVariableName)) {
111 return super.visit(node, data);
112 }
113
114 if (checkLocalVariableUsage(node, returnVariableName)) {
115 return super.visit(node, data);
116 }
117 List<ASTIfStatement> isl = node.findDescendantsOfType(ASTIfStatement.class);
118 if (isl.size() == 2) {
119 ASTIfStatement is = isl.get(0);
120 if (ifVerify(is, returnVariableName)) {
121
122 List<ASTSynchronizedStatement> ssl = is.findDescendantsOfType(ASTSynchronizedStatement.class);
123 if (ssl.size() == 1) {
124 ASTSynchronizedStatement ss = ssl.get(0);
125 isl = ss.findDescendantsOfType(ASTIfStatement.class);
126 if (isl.size() == 1) {
127 ASTIfStatement is2 = isl.get(0);
128 if (ifVerify(is2, returnVariableName)) {
129 List<ASTStatementExpression> sel = is2.findDescendantsOfType(ASTStatementExpression.class);
130 if (sel.size() == 1) {
131 ASTStatementExpression se = sel.get(0);
132 if (se.jjtGetNumChildren() == 3) {
133
134
135 if (se.jjtGetChild(0) instanceof ASTPrimaryExpression) {
136 ASTPrimaryExpression pe = (ASTPrimaryExpression) se.jjtGetChild(0);
137 if (matchName(pe, returnVariableName)) {
138 if (se.jjtGetChild(1) instanceof ASTAssignmentOperator) {
139 addViolation(data, node);
140 }
141 }
142 }
143 }
144 }
145 }
146 }
147 }
148 }
149 }
150 return super.visit(node, data);
151 }
152
153 private boolean checkLocalVariableUsage(ASTMethodDeclaration node, String returnVariableName) {
154 List<ASTLocalVariableDeclaration> locals = node.findDescendantsOfType(ASTLocalVariableDeclaration.class);
155 ASTVariableInitializer initializer = null;
156 for (ASTLocalVariableDeclaration l : locals) {
157 ASTVariableDeclaratorId id = l.getFirstDescendantOfType(ASTVariableDeclaratorId.class);
158 if (id != null && id.hasImageEqualTo(returnVariableName)) {
159 initializer = l.getFirstDescendantOfType(ASTVariableInitializer.class);
160 break;
161 }
162 }
163
164 if (initializer == null) return false;
165
166
167 if (initializer.jjtGetNumChildren() > 0 && initializer.jjtGetChild(0) instanceof ASTExpression
168 && initializer.jjtGetChild(0).jjtGetNumChildren() > 0
169 && initializer.jjtGetChild(0).jjtGetChild(0) instanceof ASTPrimaryExpression
170 && initializer.jjtGetChild(0).jjtGetChild(0).jjtGetNumChildren() > 0
171 && initializer.jjtGetChild(0).jjtGetChild(0).jjtGetChild(0) instanceof ASTPrimaryPrefix
172 && initializer.jjtGetChild(0).jjtGetChild(0).jjtGetChild(0).jjtGetNumChildren() > 0
173 && initializer.jjtGetChild(0).jjtGetChild(0).jjtGetChild(0).jjtGetChild(0) instanceof ASTName) {
174 ASTName name = (ASTName)initializer.jjtGetChild(0).jjtGetChild(0).jjtGetChild(0).jjtGetChild(0);
175 if (name == null || !volatileFields.contains(name.getImage())) {
176 return false;
177 }
178 } else {
179
180 return false;
181 }
182
183
184 List<ASTName> names = node.findDescendantsOfType(ASTName.class);
185 for (ASTName n : names) {
186 if (!n.hasImageEqualTo(returnVariableName)) continue;
187
188 Node expression = n.getNthParent(3);
189 if (expression instanceof ASTEqualityExpression) continue;
190 if (expression instanceof ASTStatementExpression) {
191 if (expression.jjtGetNumChildren() > 2 && expression.jjtGetChild(1) instanceof ASTAssignmentOperator) {
192 ASTName value = expression.jjtGetChild(2).getFirstDescendantOfType(ASTName.class);
193 if (value == null || !volatileFields.contains(value.getImage())) {
194 return false;
195 }
196 }
197 }
198 }
199
200 return true;
201 }
202
203 private boolean ifVerify(ASTIfStatement is, String varname) {
204 List<ASTPrimaryExpression> finder = is.findDescendantsOfType(ASTPrimaryExpression.class);
205 if (finder.size() > 1) {
206 ASTPrimaryExpression nullStmt = findNonVariableStmt(varname, finder.get(0), finder.get(1));
207 if (nullStmt != null) {
208 if (nullStmt.jjtGetNumChildren() == 1 && nullStmt.jjtGetChild(0) instanceof ASTPrimaryPrefix) {
209 ASTPrimaryPrefix pp2 = (ASTPrimaryPrefix) nullStmt.jjtGetChild(0);
210 if (pp2.jjtGetNumChildren() == 1 && pp2.jjtGetChild(0) instanceof ASTLiteral) {
211 ASTLiteral lit = (ASTLiteral) pp2.jjtGetChild(0);
212 if (lit.jjtGetNumChildren() == 1 && lit.jjtGetChild(0) instanceof ASTNullLiteral) {
213 return true;
214 }
215 }
216 }
217 }
218 }
219 return false;
220 }
221
222
223
224
225
226
227
228
229
230
231
232
233
234 private ASTPrimaryExpression findNonVariableStmt(String variableName, ASTPrimaryExpression apeLeft,
235 ASTPrimaryExpression apeRight) {
236 if (matchName(apeLeft, variableName)) {
237 return apeRight;
238 } else if (matchName(apeRight, variableName)) {
239 return apeLeft;
240 }
241 return null;
242 }
243
244 private boolean matchName(ASTPrimaryExpression ape, String name) {
245 if (ape.jjtGetNumChildren() == 1 && ape.jjtGetChild(0) instanceof ASTPrimaryPrefix) {
246 ASTPrimaryPrefix pp = (ASTPrimaryPrefix) ape.jjtGetChild(0);
247 String name2 = getNameFromPrimaryPrefix(pp);
248 if (name2 != null && name2.equals(name)) {
249 return true;
250 }
251 }
252 return false;
253 }
254
255 private String getNameFromPrimaryPrefix(ASTPrimaryPrefix pp) {
256 if (pp.jjtGetNumChildren() == 1 && pp.jjtGetChild(0) instanceof ASTName) {
257 return ((ASTName) pp.jjtGetChild(0)).getImage();
258 }
259 return null;
260 }
261 }