[Fb-contrib-commit] SF.net SVN: fb-contrib: [674] trunk/fb-contrib

[<dbr...@us...>]

Revision: 674
          http://svn.sourceforge.net/fb-contrib/?rev=674&view=rev
Author:   dbrosius
Date:     2006-10-26 22:27:56 -0700 (Thu, 26 Oct 2006)

Log Message:
-----------
Initial checkin SC detector (no xml support yet)

Added Paths:
-----------
    trunk/fb-contrib/samples/SC_Sample.java
    trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SuspiciousComparator.java

Added: trunk/fb-contrib/samples/SC_Sample.java
===================================================================
--- trunk/fb-contrib/samples/SC_Sample.java	                        (rev 0)
+++ trunk/fb-contrib/samples/SC_Sample.java	2006-10-27 05:27:56 UTC (rev 674)
@@ -0,0 +1,28 @@
+import java.util.Comparator;
+
+public class SC_Sample 
+{
+	public static final int T1 = 0;
+	public static final int T2 = 1;
+	
+	int t = 0;
+	class SampleComparator implements Comparator<SC_Sample>
+	{
+		public int compare(SC_Sample arg0, SC_Sample arg1) {
+			if (arg0.t == arg1.t)
+				return 0;
+
+			return -1;
+		}
+	}
+	
+	class SampleComparable implements Comparable<SC_Sample>
+	{
+		public int compareTo(SC_Sample arg0) {
+			if (t == arg0.t)
+				return 0;
+			
+			return 1;
+		}
+	}
+}

Added: trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SuspiciousComparator.java
===================================================================
--- trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SuspiciousComparator.java	                        (rev 0)
+++ trunk/fb-contrib/src/com/mebigfatguy/fbcontrib/detect/SuspiciousComparator.java	2006-10-27 05:27:56 UTC (rev 674)
@@ -0,0 +1,120 @@
+package com.mebigfatguy.fbcontrib.detect;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import org.apache.bcel.Repository;
+import org.apache.bcel.classfile.Code;
+import org.apache.bcel.classfile.JavaClass;
+import org.apache.bcel.generic.Type;
+
+import edu.umd.cs.findbugs.BugInstance;
+import edu.umd.cs.findbugs.BugReporter;
+import edu.umd.cs.findbugs.BytecodeScanningDetector;
+import edu.umd.cs.findbugs.OpcodeStack;
+import edu.umd.cs.findbugs.ba.ClassContext;
+
+/**
+ * looks for class that implement Comparator or Comparable, and whose compare or compareTo
+ * methods return constant values only, but that don't represent the three possible choice
+ * (a negative number, 0, and a positive number).
+ */
+public class SuspiciousComparator extends BytecodeScanningDetector 
+{
+	private static Map<JavaClass, String> compareClasses = new HashMap<JavaClass, String>();
+	static {
+		try {
+			compareClasses.put(Repository.lookupClass("java/lang/Comparable"), "compare:2:I");;
+			compareClasses.put(Repository.lookupClass("java.lang/Comparator"), "compareTo:1:I");
+		} catch (ClassNotFoundException cnfe) {
+		}
+	}
+	
+	private OpcodeStack stack;
+	private BugReporter bugReporter;
+	private String[] methodInfo;
+	private boolean indeterminate;
+	private boolean seenNegative;
+	private boolean seenPositive;
+	private boolean seenZero;
+	
+	
+	/**
+     * constructs a DRE detector given the reporter to report bugs on
+     * @param bugReporter the sync of bug reports
+	 */
+	public SuspiciousComparator(BugReporter bugReporter) {
+		this.bugReporter = bugReporter;
+	}
+	
+	public void visitClassContext(ClassContext classContext) {
+		try {
+			JavaClass cls = classContext.getJavaClass();
+			for (Map.Entry<JavaClass, String> entry : compareClasses.entrySet()) {
+				if (cls.implementationOf(entry.getKey())) {
+					methodInfo = entry.getValue().split(":");
+					stack = new OpcodeStack();
+					super.visitClassContext(classContext);
+					break;
+				}
+			}
+		} catch (ClassNotFoundException cnfe) {
+			bugReporter.reportMissingClass(cnfe);
+		} finally {
+			methodInfo = null;
+			stack = null;
+		}
+	}
+	
+	public void visitCode(Code obj) {
+		String methodName = getMethodName();
+		String methodSig = getMethodSig();
+		if (methodName.equals(methodInfo[0])
+		&&  methodSig.endsWith(methodInfo[2])
+		&&  (Type.getArgumentTypes(methodSig).length == Integer.valueOf(methodInfo[1]))) {
+			stack.resetForMethodEntry(this);
+			indeterminate = false;
+			seenNegative = false;
+			seenPositive = false;
+			seenZero = false;
+			super.visitCode(obj);
+			if (!indeterminate) {
+				boolean seenAll = seenNegative & seenPositive & seenZero;
+				if (!seenAll) {
+					bugReporter.reportBug(new BugInstance(this, "SC_SUSPICIOUS_COMPARATOR", NORMAL_PRIORITY)
+								.addClass(this)
+								.addMethod(this)
+								.addSourceLine(this, 0));
+				}
+			}
+		}
+	}
+	
+	public void sawOpcode(int seen) {
+		try {
+			if (indeterminate)
+				return;
+			
+			if (seen == IRETURN) {
+				if (stack.getStackDepth() > 0) {
+					OpcodeStack.Item item = stack.getStackItem(0);
+					Integer returnValue = (Integer)item.getConstant();
+					if (returnValue == null)
+						indeterminate = true;
+					else {
+						int v = returnValue.intValue();
+						if (v < 0)
+							seenNegative = true;
+						else if (v > 0)
+							seenPositive = true;
+						else
+							seenZero = true;
+					}
+				} else
+					indeterminate = true;
+			}
+		} finally {
+			stack.sawOpcode(this, seen);
+		}
+	}
+}


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