Update monet.

tools/android/findbugs_plugin/src/org/chromium/tools/findbugs/plugin/SynchronizedThisDetector.java

Index: tools/android/findbugs_plugin/src/org/chromium/tools/findbugs/plugin/SynchronizedThisDetector.java
diff --git a/tools/android/findbugs_plugin/src/org/chromium/tools/findbugs/plugin/SynchronizedThisDetector.java b/tools/android/findbugs_plugin/src/org/chromium/tools/findbugs/plugin/SynchronizedThisDetector.java
new file mode 100644
index 0000000000000000000000000000000000000000..9a4e5e12226c769ef60fdedf165b7999fbfad2aa
--- /dev/null
+++ b/tools/android/findbugs_plugin/src/org/chromium/tools/findbugs/plugin/SynchronizedThisDetector.java
@@ -0,0 +1,73 @@
+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.tools.findbugs.plugin;
+
+import org.apache.bcel.classfile.Code;
+
+import edu.umd.cs.findbugs.BugInstance;
+import edu.umd.cs.findbugs.BugReporter;
+import edu.umd.cs.findbugs.bcel.OpcodeStackDetector;
+
+/**
+ * This class detects the synchronized(this).
+ *
+ * The pattern of byte code of synchronized(this) is
+ * aload_0         # Load the 'this' pointer on top of stack
+ * dup             # Duplicate the 'this' pointer
+ * astore_x        # Store this for late use, it might be astore.
+ * monitorenter
+ */
+public class SynchronizedThisDetector extends OpcodeStackDetector {
+    private static final int PATTERN[] = {ALOAD_0, DUP, 0xff, 0xff, MONITORENTER};
+
+    private int mStep = 0;
+    private BugReporter mBugReporter;
+
+    public SynchronizedThisDetector(BugReporter bugReporter) {
+        mBugReporter = bugReporter;
+    }
+
+    @Override
+    public void visit(Code code) {
+        mStep = 0;
+        super.visit(code);
+    }
+
+    @Override
+    public void sawOpcode(int seen) {
+        if (PATTERN[mStep] == seen) {
+            mStep++;
+            if (mStep == PATTERN.length) {
+                mBugReporter.reportBug(new BugInstance(this, "CHROMIUM_SYNCHRONIZED_THIS",
+                                                       NORMAL_PRIORITY)
+                        .addClassAndMethod(this)
+                        .addSourceLine(this));
+                mStep = 0;
+                return;
+            }
+        } else if (mStep == 2) {
+            // This could be astore_x
+            switch (seen) {
+                case ASTORE_0:
+                case ASTORE_1:
+                case ASTORE_2:
+                case ASTORE_3:
+                    mStep += 2;
+                    break;
+                case ASTORE:
+                    mStep++;
+                    break;
+                default:
+                    mStep = 0;
+                    break;
+            }
+        } else if (mStep == 3) {
+            // Could be any byte following the ASTORE.
+            mStep++;
+        } else {
+            mStep = 0;
+        }
+    }
+}