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.Build;
20 
21 import com.android.internal.annotations.VisibleForTesting;
22 import com.android.internal.util.IndentingPrintWriter;
23 import com.android.systemui.Dumpable;
24 
25 import java.io.FileDescriptor;
26 import java.io.PrintWriter;
27 import java.io.Writer;
28 import java.util.Collection;
29 
30 /**
31  * Detects leaks.
32  */
33 public class LeakDetector implements Dumpable {
34 
35     public static final boolean ENABLED = Build.IS_DEBUGGABLE;
36 
37     private final TrackedCollections mTrackedCollections;
38     private final TrackedGarbage mTrackedGarbage;
39     private final TrackedObjects mTrackedObjects;
40 
41     @VisibleForTesting
LeakDetector(TrackedCollections trackedCollections, TrackedGarbage trackedGarbage, TrackedObjects trackedObjects)42     public LeakDetector(TrackedCollections trackedCollections,
43             TrackedGarbage trackedGarbage,
44             TrackedObjects trackedObjects) {
45         mTrackedCollections = trackedCollections;
46         mTrackedGarbage = trackedGarbage;
47         mTrackedObjects = trackedObjects;
48     }
49 
50     /**
51      * Tracks an instance that has a high leak risk (i.e. has complex ownership and references
52      * a large amount of memory).
53      *
54      * The LeakDetector will monitor and keep weak references to such instances, dump statistics
55      * about them in a bugreport, and in the future dump the heap if their count starts growing
56      * unreasonably.
57      *
58      * This should be called when the instance is first constructed.
59      */
trackInstance(T object)60     public <T> void trackInstance(T object) {
61         if (mTrackedObjects != null) {
62             mTrackedObjects.track(object);
63         }
64     }
65 
66     /**
67      * Tracks a collection that is at risk of leaking large objects, e.g. a collection of
68      * dynamically registered listeners.
69      *
70      * The LeakDetector will monitor and keep weak references to such collections, dump
71      * statistics about them in a bugreport, and in the future dump the heap if their size starts
72      * growing unreasonably.
73      *
74      * This should be called whenever the collection grows.
75      *
76      * @param tag A tag for labeling the collection in a bugreport
77      */
trackCollection(Collection<T> collection, String tag)78     public <T> void trackCollection(Collection<T> collection, String tag) {
79         if (mTrackedCollections != null) {
80             mTrackedCollections.track(collection, tag);
81         }
82     }
83 
84     /**
85      * Tracks an instance that should become garbage soon.
86      *
87      * The LeakDetector will monitor and keep weak references to such garbage, dump
88      * statistics about them in a bugreport, and in the future dump the heap if it is not
89      * collected reasonably soon.
90      *
91      * This should be called when the last strong reference to the instance is dropped.
92      */
trackGarbage(Object o)93     public void trackGarbage(Object o) {
94         if (mTrackedGarbage != null) {
95             mTrackedGarbage.track(o);
96         }
97     }
98 
getTrackedGarbage()99     TrackedGarbage getTrackedGarbage() {
100         return mTrackedGarbage;
101     }
102 
103     @Override
dump(FileDescriptor df, PrintWriter w, String[] args)104     public void dump(FileDescriptor df, PrintWriter w, String[] args) {
105         IndentingPrintWriter pw = new IndentingPrintWriter(w, "  ");
106 
107         pw.println("SYSUI LEAK DETECTOR");
108         pw.increaseIndent();
109 
110         if (mTrackedCollections != null && mTrackedGarbage != null) {
111             pw.println("TrackedCollections:");
112             pw.increaseIndent();
113             mTrackedCollections.dump(pw, (col) -> !TrackedObjects.isTrackedObject(col));
114             pw.decreaseIndent();
115             pw.println();
116 
117             pw.println("TrackedObjects:");
118             pw.increaseIndent();
119             mTrackedCollections.dump(pw, TrackedObjects::isTrackedObject);
120             pw.decreaseIndent();
121             pw.println();
122 
123             pw.print("TrackedGarbage:");
124             pw.increaseIndent();
125             mTrackedGarbage.dump(pw);
126             pw.decreaseIndent();
127         } else {
128             pw.println("disabled");
129         }
130         pw.decreaseIndent();
131         pw.println();
132     }
133 
create()134     public static LeakDetector create() {
135         if (ENABLED) {
136             TrackedCollections collections = new TrackedCollections();
137             return new LeakDetector(collections, new TrackedGarbage(collections),
138                     new TrackedObjects(collections));
139         } else {
140             return new LeakDetector(null, null, null);
141         }
142     }
143 }
144