1 /* 2 * Copyright (C) 2013 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.server; 18 19 import android.os.Handler; 20 import android.os.Trace; 21 22 /** 23 * Shared singleton foreground thread for the system. This is a thread for regular 24 * foreground service operations, which shouldn't be blocked by anything running in 25 * the background. In particular, the shared background thread could be doing 26 * relatively long-running operations like saving state to disk (in addition to 27 * simply being a background priority), which can cause operations scheduled on it 28 * to be delayed for a user-noticeable amount of time. 29 */ 30 public final class FgThread extends ServiceThread { 31 private static FgThread sInstance; 32 private static Handler sHandler; 33 34 private FgThread() { 35 super("android.fg", android.os.Process.THREAD_PRIORITY_DEFAULT, true /*allowIo*/); 36 } 37 38 private static void ensureThreadLocked() { 39 if (sInstance == null) { 40 sInstance = new FgThread(); 41 sInstance.start(); 42 sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_ACTIVITY_MANAGER); 43 sHandler = new Handler(sInstance.getLooper()); 44 } 45 } 46 47 public static FgThread get() { 48 synchronized (UiThread.class) { 49 ensureThreadLocked(); 50 return sInstance; 51 } 52 } 53 54 public static Handler getHandler() { 55 synchronized (UiThread.class) { 56 ensureThreadLocked(); 57 return sHandler; 58 } 59 } 60 } 61
