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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package libcore.heapdumper;
     18 
     19 import android.app.Activity;
     20 import android.app.Instrumentation;
     21 import android.os.Bundle;
     22 import android.os.Environment;
     23 import android.util.Log;
     24 
     25 import java.io.File;
     26 import java.io.FileOutputStream;
     27 import java.io.IOException;
     28 import java.io.OutputStream;
     29 
     30 /**
     31  * An abstract base class for an {@link Instrumentation} that takes some measurement, performs some
     32  * action, and then takes the measurement again, all without launching any activities.
     33  *
     34  * <p>The metric to be collected is defined by the concrete subclass's implementation of
     35  * {@link #takeMeasurement}. The action to be performed is determined by an invocation argument.
     36  *
     37  * <p>The instrumentation should be invoked with two arguments:
     38  * <ul>
     39  *     <li>one called {@code dumpdir} which gives the name of a directory to put the dumps in,
     40  *     relative to the public external storage directory;
     41  *     <li>one called {@code action} which gives the name of an {@link Actions} value to run between
     42  *     the two measurements.
     43  * </ul>
     44  *
     45  * <p>If there is a problem, it will try to create a file called {@code error} in the output
     46  * directory, containing a failure message.
     47  */
     48 public abstract class AbstractMetricInstrumentation extends Instrumentation {
     49 
     50     private static final String TAG = "AbstractMetricInstrumentation";
     51 
     52     private File mOutputDirectory;
     53 
     54     @Override
     55     public void onCreate(Bundle icicle) {
     56         mOutputDirectory = resolveOutputDirectory(icicle);
     57         try {
     58             Runnable mAction = loadAction(icicle);
     59             takeMeasurement("before");
     60             mAction.run();
     61             takeMeasurement("after");
     62         } catch (Exception e) {
     63             recordException(e);
     64         }
     65         super.onCreate(icicle);
     66         finish(Activity.RESULT_OK, new Bundle());
     67     }
     68 
     69     /**
     70      * Takes a measurement, including the given label in the filename of the output.
     71      */
     72     protected abstract void takeMeasurement(String label) throws IOException;
     73 
     74     /**
     75      * Returns a {@link File} in the correct output directory with the given relative filename.
     76      */
     77     protected final File resolveRelativeOutputFilename(String relativeOutputFilename) {
     78         return new File(mOutputDirectory, relativeOutputFilename);
     79     }
     80 
     81     /**
     82      * Does its best to force as much garbage as possible to be collected.
     83      */
     84     protected final void tryRemoveGarbage() {
     85         Runtime runtime = Runtime.getRuntime();
     86         // Do a GC run.
     87         runtime.gc();
     88         // Run finalizers for any objects pending finalization.
     89         runtime.runFinalization();
     90         // Do another GC run, for objects made eligible for collection by the finalization process.
     91         runtime.gc();
     92     }
     93 
     94     /**
     95      * Resolves the directory to use for output, based on the arguments in the bundle.
     96      */
     97     private static File resolveOutputDirectory(Bundle icicle) {
     98         String relativeDirectoryName = icicle.getString("dumpdir");
     99         if (relativeDirectoryName == null) {
    100             throw new IllegalArgumentException(
    101                     "Instrumentation invocation missing dumpdir argument");
    102         }
    103         if (!Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
    104             throw new IllegalStateException("External storage unavailable");
    105         }
    106         File dir = Environment.getExternalStoragePublicDirectory(relativeDirectoryName);
    107         if (!dir.isDirectory()) {
    108             throw new IllegalArgumentException(
    109                     "Instrumentation invocation's dumpdir argument is not a directory: "
    110                             + dir.getAbsolutePath());
    111         }
    112         return dir;
    113     }
    114 
    115     /**
    116      * Returns the {@link Runnable} to run between measurements, based on the arguments in the
    117      * bundle.
    118      */
    119     private static Runnable loadAction(Bundle icicle) {
    120         String name = icicle.getString("action");
    121         if (name == null) {
    122             throw new IllegalArgumentException(
    123                     "Instrumentation invocation missing action argument");
    124         }
    125         return Actions.valueOf(name);
    126     }
    127 
    128     /**
    129      * Write an {@code error} file into {@link #mOutputDirectory} containing the message of the
    130      * exception.
    131      */
    132     private void recordException(Exception e) {
    133         Log.e(TAG, "Exception while taking measurements", e);
    134         String contents = e.getMessage();
    135         File errorFile = new File(mOutputDirectory, "error");
    136         try {
    137             try (OutputStream errorStream = new FileOutputStream(errorFile)) {
    138                 errorStream.write(contents.getBytes("UTF-8"));
    139             }
    140         } catch (IOException e2) {
    141             throw new RuntimeException("Exception writing error file!", e2);
    142         }
    143     }
    144 }
    145