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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 com.android.systemui.util.leak;
     18 
     19 import android.os.SystemClock;
     20 
     21 import java.io.PrintWriter;
     22 import java.lang.ref.WeakReference;
     23 import java.util.Collection;
     24 import java.util.Map;
     25 import java.util.function.Predicate;
     26 
     27 /**
     28  * Tracks the size of collections.
     29  */
     30 public class TrackedCollections {
     31     private static final long MILLIS_IN_MINUTE = 60 * 1000;
     32     private static final long HALFWAY_DELAY = 30 * MILLIS_IN_MINUTE;
     33 
     34     private final WeakIdentityHashMap<Collection<?>, CollectionState> mCollections
     35             = new WeakIdentityHashMap<>();
     36 
     37     /**
     38      * @see LeakDetector#trackCollection(Collection, String)
     39      */
     40     public synchronized void track(Collection<?> collection, String tag) {
     41         CollectionState collectionState = mCollections.get(collection);
     42         if (collectionState == null) {
     43             collectionState = new CollectionState();
     44             collectionState.tag = tag;
     45             collectionState.startUptime = SystemClock.uptimeMillis();
     46             mCollections.put(collection, collectionState);
     47         }
     48         if (collectionState.halfwayCount == -1
     49                 && SystemClock.uptimeMillis() - collectionState.startUptime > HALFWAY_DELAY) {
     50             collectionState.halfwayCount = collectionState.lastCount;
     51         }
     52         collectionState.lastCount = collection.size();
     53         collectionState.lastUptime = SystemClock.uptimeMillis();
     54     }
     55 
     56     private static class CollectionState {
     57         String tag;
     58         long startUptime;
     59         /** The number of elements in the collection at startUptime + HALFWAY_DELAY */
     60         int halfwayCount = -1;
     61         /** The number of elements in the collection at lastUptime */
     62         int lastCount = -1;
     63         long lastUptime;
     64 
     65         /**
     66          * Dump statistics about the tracked collection:
     67          * - the tag
     68          * - average elements inserted per hour during
     69          *   - the first 30min of its existence
     70          *   - after the first 30min
     71          *   - overall
     72          * - the current size of the collection
     73          */
     74         void dump(PrintWriter pw) {
     75             long now = SystemClock.uptimeMillis();
     76 
     77             pw.format("%s: %.2f (start-30min) / %.2f (30min-now) / %.2f (start-now)"
     78                             + " (growth rate in #/hour); %d (current size)",
     79                     tag,
     80                     ratePerHour(startUptime, 0, startUptime + HALFWAY_DELAY, halfwayCount),
     81                     ratePerHour(startUptime + HALFWAY_DELAY, halfwayCount, now, lastCount),
     82                     ratePerHour(startUptime, 0, now, lastCount),
     83                     lastCount);
     84         }
     85 
     86         private float ratePerHour(long uptime1, int count1, long uptime2, int count2) {
     87             if (uptime1 >= uptime2 || count1 < 0 || count2 < 0) {
     88                 return Float.NaN;
     89             }
     90             return ((float) count2 - count1) / (uptime2 - uptime1) * 60 * MILLIS_IN_MINUTE;
     91         }
     92     }
     93 
     94     public synchronized void dump(PrintWriter pw, Predicate<Collection<?>> filter) {
     95         for (Map.Entry<WeakReference<Collection<?>>, CollectionState> entry
     96                 : mCollections.entrySet()) {
     97             Collection<?> key = entry.getKey().get();
     98             if (filter == null || key != null && filter.test(key)) {
     99                 entry.getValue().dump(pw);
    100                 pw.println();
    101             }
    102         }
    103     }
    104 }
    105