MTP: bring up MTP perf tests in Crystalball

/*

 * Copyright (C) 2020 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.

 */

package android.mtp_perf;

import android.app.Activity;

import android.content.Context;

import android.os.Bundle;

import android.os.ParcelFileDescriptor;

import android.os.ProxyFileDescriptorCallback;

import android.os.storage.StorageManager;

import android.system.ErrnoException;

import androidx.test.InstrumentationRegistry;

import androidx.test.filters.LargeTest;

import androidx.test.runner.AndroidJUnit4;

import org.junit.Test;

import org.junit.runner.RunWith;

import java.io.IOException;

@RunWith(AndroidJUnit4.class)

@LargeTest

public class AppFusePerfTest {

    static final int SIZE = 10 * 1024 * 1024; // 10MB

    @Test

    public void testReadWriteFile() throws IOException {

        final Context context = InstrumentationRegistry.getInstrumentation().getTargetContext();

        final StorageManager storageManager = context.getSystemService(StorageManager.class);

        final byte[] bytes = new byte[SIZE];

        final int samples = 100;

        final double[] readTime = new double[samples];

        final double[] writeTime = new double[samples];

        for (int i = 0; i < samples; i++) {

            final ParcelFileDescriptor fd = storageManager.openProxyFileDescriptor(

                    ParcelFileDescriptor.MODE_READ_ONLY, new TestCallback());

            try (final ParcelFileDescriptor.AutoCloseInputStream stream =

                    new ParcelFileDescriptor.AutoCloseInputStream(fd)) {

                final long startTime = System.nanoTime();

                stream.read(bytes);

                readTime[i] = (System.nanoTime() - startTime) / 1000.0 / 1000.0;

            }

        }

        for (int i = 0; i < samples; i++) {

            final ParcelFileDescriptor fd = storageManager.openProxyFileDescriptor(

                    ParcelFileDescriptor.MODE_WRITE_ONLY | ParcelFileDescriptor.MODE_TRUNCATE,

                    new TestCallback());

            try (final ParcelFileDescriptor.AutoCloseOutputStream stream =

                    new ParcelFileDescriptor.AutoCloseOutputStream(fd)) {

                final long startTime = System.nanoTime();

                stream.write(bytes);

                writeTime[i] = (System.nanoTime() - startTime) / 1000.0 / 1000.0;

            }

        }

        double readAverage = 0;

        double writeAverage = 0;

        double readSquaredAverage = 0;

        double writeSquaredAverage = 0;

        for (int i = 0; i < samples; i++) {

            readAverage += readTime[i];

            writeAverage += writeTime[i];

            readSquaredAverage += readTime[i] * readTime[i];

            writeSquaredAverage += writeTime[i] * writeTime[i];

        }

        readAverage /= samples;

        writeAverage /= samples;

        readSquaredAverage /= samples;

        writeSquaredAverage /= samples;

        final Bundle results = new Bundle();

        results.putDouble("readAverage", readAverage);

        results.putDouble("readStandardDeviation",

                Math.sqrt(readSquaredAverage - readAverage * readAverage));

        results.putDouble("writeAverage", writeAverage);

        results.putDouble("writeStandardDeviation",

                Math.sqrt(writeSquaredAverage - writeAverage * writeAverage));

        InstrumentationRegistry.getInstrumentation().sendStatus(Activity.RESULT_OK, results);

    }

    private static class TestCallback extends ProxyFileDescriptorCallback {

        @Override

        public long onGetSize() throws ErrnoException {

            return SIZE;

        }

        @Override

        public int onRead(long offset, int size, byte[] data) throws ErrnoException {

            return size;

        }

        @Override

        public int onWrite(long offset, int size, byte[] data) throws ErrnoException {

            return size;

        }

        @Override

        public void onFsync() throws ErrnoException {}

        @Override

        public void onRelease() {}

    }

}