Change when sampling thread is reset during shutdown to prevent races.

Also adds some extra argument checking and testing for tracing.

Bug: 17412385

(cherry picked from commit f8bdd4e783842577e49f418a0b5962ba49dfdd93)

Change-Id: Ifc4f1a296155d73255b29d264b5475024e6419da
diff --git a/test/099-vmdebug/src/Main.java b/test/099-vmdebug/src/Main.java
new file mode 100644
index 0000000..d51ec6e
--- /dev/null
+++ b/test/099-vmdebug/src/Main.java
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.io.File;
+import java.io.IOException;
+import java.lang.reflect.Method;
+
+public class Main {
+    public static void main(String[] args) throws Exception {
+        String name = System.getProperty("java.vm.name");
+        if (!"Dalvik".equals(name)) {
+            System.out.println("This test is not supported on " + name);
+            return;
+        }
+        testMethodTracing();
+    }
+
+    private static void testMethodTracing() throws Exception {
+        String tempFileName;
+        if (new File("/tmp").isDirectory()) {
+            tempFileName = "/tmp/test.trace";
+        } else if (new File("/sdcard").isDirectory()) {
+            tempFileName = "/sdcard/test.trace";
+        } else {
+            System.out.println("Can't find proper output directory for trace file");
+            return;
+        }
+        File tempFile = new File(tempFileName);
+        tempFile.delete();
+
+        System.out.println("Confirm enable/disable");
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        VMDebug.startMethodTracing(tempFileName, 0, 0, false, 0);
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        VMDebug.stopMethodTracing();
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        if (tempFile.length() == 0) {
+            System.out.println("ERROR: tracing output file is empty");
+        }
+
+        System.out.println("Confirm sampling");
+        VMDebug.startMethodTracing(tempFileName, 0, 0, true, 1000);
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        VMDebug.stopMethodTracing();
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        if (tempFile.length() == 0) {
+            System.out.println("ERROR: sample tracing output file is empty");
+        }
+
+        System.out.println("Test starting when already started");
+        VMDebug.startMethodTracing(tempFileName, 0, 0, false, 0);
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        VMDebug.startMethodTracing(tempFileName, 0, 0, false, 0);
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+
+        System.out.println("Test stopping when already stopped");
+        VMDebug.stopMethodTracing();
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+        VMDebug.stopMethodTracing();
+        System.out.println("status=" + VMDebug.getMethodTracingMode());
+
+        System.out.println("Test tracing with empty filename");
+        try {
+            VMDebug.startMethodTracing("", 0, 0, false, 0);
+            System.out.println("Should have thrown an exception");
+        } catch (Exception e) {
+            System.out.println("Got expected exception");
+        }
+
+        System.out.println("Test tracing with bogus (< 1024 && != 0) filesize");
+        try {
+            VMDebug.startMethodTracing(tempFileName, 1000, 0, false, 0);
+            System.out.println("Should have thrown an exception");
+        } catch (Exception e) {
+            System.out.println("Got expected exception");
+        }
+
+        System.out.println("Test sampling with bogus (<= 0) interval");
+        try {
+            VMDebug.startMethodTracing(tempFileName, 0, 0, true, 0);
+            System.out.println("Should have thrown an exception");
+        } catch (Exception e) {
+            System.out.println("Got expected exception");
+        }
+
+        tempFile.delete();
+    }
+
+    private static class VMDebug {
+        private static final Method startMethodTracingMethod;
+        private static final Method stopMethodTracingMethod;
+        private static final Method getMethodTracingModeMethod;
+        static {
+            try {
+                Class c = Class.forName("dalvik.system.VMDebug");
+                startMethodTracingMethod = c.getDeclaredMethod("startMethodTracing", String.class,
+                        Integer.TYPE, Integer.TYPE, Boolean.TYPE, Integer.TYPE);
+                stopMethodTracingMethod = c.getDeclaredMethod("stopMethodTracing");
+                getMethodTracingModeMethod = c.getDeclaredMethod("getMethodTracingMode");
+            } catch (Exception e) {
+                throw new RuntimeException(e);
+            }
+        }
+
+        public static void startMethodTracing(String filename, int bufferSize, int flags,
+                boolean samplingEnabled, int intervalUs) throws Exception {
+            startMethodTracingMethod.invoke(null, filename, bufferSize, flags, samplingEnabled,
+                    intervalUs);
+        }
+        public static void stopMethodTracing() throws Exception {
+            stopMethodTracingMethod.invoke(null);
+        }
+        public static int getMethodTracingMode() throws Exception {
+            return (int) getMethodTracingModeMethod.invoke(null);
+        }
+    }
+}