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Java > Open Source Codes > edu > umd > cs > findbugs > detect > InheritanceUnsafeGetResource


1 /*
2  * FindBugs - Find bugs in Java programs
3  * Copyright (C) 2004-2006 University of Maryland
4  *
5  * This library is free software; you can redistribute it and/or
6  * modify it under the terms of the GNU Lesser General Public
7  * License as published by the Free Software Foundation; either
8  * version 2.1 of the License, or (at your option) any later version.
9  *
10  * This library is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13  * Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public
16  * License along with this library; if not, write to the Free Software
17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18  */
19
20 package edu.umd.cs.findbugs.detect;
21
22
23 import java.util.Set JavaDoc;
24
25 import edu.umd.cs.findbugs.*;
26 import edu.umd.cs.findbugs.ba.AnalysisContext;
27 import edu.umd.cs.findbugs.ba.ch.Subtypes;
28
29 import org.apache.bcel.classfile.*;
30
31 public class InheritanceUnsafeGetResource extends BytecodeScanningDetector implements StatelessDetector {
32
33     private BugReporter bugReporter;
34     private boolean classIsFinal;
35 // private boolean methodIsVisibleToOtherPackages;
36 private boolean classIsVisibleToOtherPackages;
37 // private boolean methodIsFinal;
38 private boolean methodIsStatic;
39     int state = 0;
40     int sawGetClass;
41     boolean reportedForThisClass;
42     String JavaDoc stringConstant;
43     int prevOpcode;
44
45     public InheritanceUnsafeGetResource(BugReporter bugReporter) {
46         this.bugReporter = bugReporter;
47     }
48
49
50
51     @Override JavaDoc
52          public void visit(JavaClass obj) {
53         classIsFinal = obj.isFinal();
54         reportedForThisClass = false;
55         classIsVisibleToOtherPackages = obj.isPublic() || obj.isProtected();
56     }
57
58     @Override JavaDoc
59          public void visit(Method obj) {
60         methodIsStatic = obj.isStatic();
61         state = 0;
62         sawGetClass = -100;
63     }
64
65     @Override JavaDoc
66          public void sawOpcode(int seen) {
67         if (reportedForThisClass) return;
68
69         
70         switch (seen) {
71         case LDC:
72             Constant constantValue = getConstantRefOperand();
73             if (constantValue instanceof ConstantClass)
74                 sawGetClass = -100;
75             else if (constantValue instanceof ConstantString) {
76                 stringConstant = ((ConstantString)constantValue).getBytes(getConstantPool());
77             }
78             break;
79             
80         case ALOAD_0:
81             state = 1;
82             break;
83         case INVOKEVIRTUAL:
84             if (getClassConstantOperand().equals("java/lang/Class")
85                     && (getNameConstantOperand().equals("getResource")
86                     || getNameConstantOperand().equals("getResourceAsStream"))
87                     && sawGetClass + 10 >= getPC()) {
88                  Subtypes subtypes = AnalysisContext.currentAnalysisContext()
89                     .getSubtypes();
90                  int priority = NORMAL_PRIORITY;
91                  if (prevOpcode == LDC && stringConstant != null && stringConstant.charAt(0)=='/')
92                      priority = LOW_PRIORITY;
93                  else {
94                  String JavaDoc myPackagename = getThisClass().getPackageName();
95                 Set JavaDoc<JavaClass> mySubtypes = subtypes.getTransitiveSubtypes(getThisClass());
96                 if (mySubtypes.isEmpty()) priority++;
97                 else for(JavaClass c : mySubtypes) {
98                         if (!c.getPackageName().equals(myPackagename)) {
99                             priority--;
100                             break;
101                         }
102                     }
103                  }
104                 bugReporter.reportBug(new BugInstance(this, "UI_INHERITANCE_UNSAFE_GETRESOURCE",
105                         priority)
106                         .addClassAndMethod(this)
107                         .addSourceLine(this));
108                 reportedForThisClass = true;
109
110             } else if (state == 1
111                     && !methodIsStatic
112                     && !classIsFinal
113                     && classIsVisibleToOtherPackages
114                     && getNameConstantOperand().equals("getClass")
115                     && getSigConstantOperand().equals("()Ljava/lang/Class;")) {
116                 sawGetClass = getPC();
117             }
118             state = 0;
119             break;
120         default:
121             state = 0;
122             break;
123         }
124         if (seen != LDC) stringConstant = null;
125         prevOpcode = seen;
126
127     }
128
129 }
130
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