/*
 * Copyright (C) 2015 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 com.android.systemui;

import com.android.internal.annotations.VisibleForTesting;
import com.android.systemui.util.Assert;

import android.os.Handler;
import android.view.Choreographer;

import java.util.ArrayList;

Utility class for methods used to dejank the UI.
/**
 * Utility class for methods used to dejank the UI.
 */
public class DejankUtils {

    private static final Choreographer sChoreographer = Choreographer.getInstance();
    private static final Handler sHandler = new Handler();
    private static final ArrayList<Runnable> sPendingRunnables = new ArrayList<>();

    
Only for testing.
/**
     * Only for testing.
     */
    private static boolean sImmediate;

    private static final Runnable sAnimationCallbackRunnable = new Runnable() {
        @Override
        public void run() {
            for (int i = 0; i < sPendingRunnables.size(); i++) {
                sHandler.post(sPendingRunnables.get(i));
            }
            sPendingRunnables.clear();
        }
    };

    
Executes r after performTraversals. Use this do to CPU heavy work for which the timing is not critical for animation. The work is then scheduled at the same time RenderThread is doing its thing, leading to better parallelization. 
Needs to be called from the main thread.
/**
     * Executes {@code r} after performTraversals. Use this do to CPU heavy work for which the
     * timing is not critical for animation. The work is then scheduled at the same time
     * RenderThread is doing its thing, leading to better parallelization.
     *
     * <p>Needs to be called from the main thread.
     */
    public static void postAfterTraversal(Runnable r) {
        if (sImmediate) {
            r.run();
            return;
        }
        Assert.isMainThread();
        sPendingRunnables.add(r);
        postAnimationCallback();
    }

    
Removes a previously scheduled runnable.
Needs to be called from the main thread.
/**
     * Removes a previously scheduled runnable.
     *
     * <p>Needs to be called from the main thread.
     */
    public static void removeCallbacks(Runnable r) {
        Assert.isMainThread();
        sPendingRunnables.remove(r);
        sHandler.removeCallbacks(r);
    }

    private static void postAnimationCallback() {
        sChoreographer.postCallback(Choreographer.CALLBACK_ANIMATION, sAnimationCallbackRunnable,
                null);
    }

    @VisibleForTesting
    public static void setImmediate(boolean immediate) {
        sImmediate = immediate;
    }
}