1/*
2 * Copyright (C) 2015 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
17package com.android.systemui;
18
19import android.os.Handler;
20import android.os.Looper;
21import android.view.Choreographer;
22
23import java.util.ArrayList;
24
25/**
26 * Utility class for methods used to dejank the UI.
27 */
28public class DejankUtils {
29
30    private static final Choreographer sChoreographer = Choreographer.getInstance();
31    private static final Handler sHandler = new Handler();
32
33    private static final ArrayList<Runnable> sPendingRunnables = new ArrayList<>();
34
35    private static final Runnable sAnimationCallbackRunnable = new Runnable() {
36        @Override
37        public void run() {
38            for (int i = 0; i < sPendingRunnables.size(); i++) {
39                sHandler.post(sPendingRunnables.get(i));
40            }
41            sPendingRunnables.clear();
42        }
43    };
44
45    /**
46     * Executes {@code r} after performTraversals. Use this do to CPU heavy work for which the
47     * timing is not critical for animation. The work is then scheduled at the same time
48     * RenderThread is doing its thing, leading to better parallelization.
49     *
50     * <p>Needs to be called from the main thread.
51     */
52    public static void postAfterTraversal(Runnable r) {
53        throwIfNotCalledOnMainThread();
54        sPendingRunnables.add(r);
55        postAnimationCallback();
56    }
57
58    /**
59     * Removes a previously scheduled runnable.
60     *
61     * <p>Needs to be called from the main thread.
62     */
63    public static void removeCallbacks(Runnable r) {
64        throwIfNotCalledOnMainThread();
65        sPendingRunnables.remove(r);
66        sHandler.removeCallbacks(r);
67    }
68
69    private static void postAnimationCallback() {
70        sChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, sAnimationCallbackRunnable,
71                null);
72    }
73
74    private static void throwIfNotCalledOnMainThread() {
75        if (!Looper.getMainLooper().isCurrentThread()) {
76            throw new IllegalStateException("should be called from the main thread.");
77        }
78    }
79}
80