/*
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* Copyright (C) 2013 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.android.server;
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import android.os.Handler;
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import android.os.Looper;
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import android.os.Process;
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import android.os.Trace;
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/**
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* Shared singleton thread for showing UI. This is a foreground thread, and in
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* additional should not have operations that can take more than a few ms scheduled
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* on it to avoid UI jank.
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*/
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public final class UiThread extends ServiceThread {
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private static final long SLOW_DISPATCH_THRESHOLD_MS = 100;
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private static final long SLOW_DELIVERY_THRESHOLD_MS = 200;
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private static UiThread sInstance;
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private static Handler sHandler;
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private UiThread() {
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super("android.ui", Process.THREAD_PRIORITY_FOREGROUND, false /*allowIo*/);
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}
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@Override
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public void run() {
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// Make sure UiThread is in the fg stune boost group
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Process.setThreadGroup(Process.myTid(), Process.THREAD_GROUP_TOP_APP);
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super.run();
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}
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private static void ensureThreadLocked() {
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if (sInstance == null) {
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sInstance = new UiThread();
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sInstance.start();
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final Looper looper = sInstance.getLooper();
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looper.setTraceTag(Trace.TRACE_TAG_SYSTEM_SERVER);
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looper.setSlowLogThresholdMs(
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SLOW_DISPATCH_THRESHOLD_MS, SLOW_DELIVERY_THRESHOLD_MS);
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sHandler = new Handler(sInstance.getLooper());
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}
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}
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public static UiThread get() {
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synchronized (UiThread.class) {
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ensureThreadLocked();
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return sInstance;
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}
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}
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public static Handler getHandler() {
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synchronized (UiThread.class) {
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ensureThreadLocked();
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return sHandler;
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}
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}
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}
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