/*
 * Copyright (C) 2015 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;

/**
 * Controls deoptimization using dalvik.system.VMDebug class.
 */
public class DeoptimizationController {
    private static final String TEMP_FILE_NAME_PREFIX = "test";
    private static final String TEMP_FILE_NAME_SUFFIX = ".trace";

    private static File createTempFile() throws Exception {
        try {
            return  File.createTempFile(TEMP_FILE_NAME_PREFIX, TEMP_FILE_NAME_SUFFIX);
        } catch (IOException e) {
            System.setProperty("java.io.tmpdir", "/data/local/tmp");
            try {
                return File.createTempFile(TEMP_FILE_NAME_PREFIX, TEMP_FILE_NAME_SUFFIX);
            } catch (IOException e2) {
                System.setProperty("java.io.tmpdir", "/sdcard");
                return File.createTempFile(TEMP_FILE_NAME_PREFIX, TEMP_FILE_NAME_SUFFIX);
            }
        }
    }

    public static void startDeoptimization() {
        File tempFile = null;
        try {
            tempFile = createTempFile();
            String tempFileName = tempFile.getPath();

            VMDebug.startMethodTracing(tempFileName, 0, 0, false, 1000);
            if (VMDebug.getMethodTracingMode() == 0) {
                throw new IllegalStateException("Not tracing.");
            }
        } catch (Exception exc) {
            exc.printStackTrace(System.out);
        } finally {
            if (tempFile != null) {
                tempFile.delete();
            }
        }
    }

    public static void stopDeoptimization() {
        try {
            VMDebug.stopMethodTracing();
            if (VMDebug.getMethodTracingMode() != 0) {
                throw new IllegalStateException("Still tracing.");
            }
        } catch (Exception exc) {
            exc.printStackTrace(System.out);
        }
    }

    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);
        }
    }
}