Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 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; |
Jeff Sharkey | 74cd3de | 2016-04-06 17:40:54 -0600 | [diff] [blame] | 20 | import android.os.Trace; |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 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 | */ |
Jeff Brown | 4ccb823 | 2014-01-16 22:16:42 -0800 | [diff] [blame] | 30 | public final class FgThread extends ServiceThread { |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 31 | private static FgThread sInstance; |
| 32 | private static Handler sHandler; |
| 33 | |
| 34 | private FgThread() { |
Jeff Brown | 4ccb823 | 2014-01-16 22:16:42 -0800 | [diff] [blame] | 35 | super("android.fg", android.os.Process.THREAD_PRIORITY_DEFAULT, true /*allowIo*/); |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 36 | } |
| 37 | |
| 38 | private static void ensureThreadLocked() { |
| 39 | if (sInstance == null) { |
| 40 | sInstance = new FgThread(); |
| 41 | sInstance.start(); |
Michael Wright | daf72b1 | 2017-11-01 22:24:08 +0000 | [diff] [blame] | 42 | sInstance.getLooper().setTraceTag(Trace.TRACE_TAG_SYSTEM_SERVER); |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 43 | sHandler = new Handler(sInstance.getLooper()); |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 44 | } |
| 45 | } |
| 46 | |
| 47 | public static FgThread get() { |
yangbingqian | 6ecf9af | 2017-05-10 20:31:15 +0800 | [diff] [blame] | 48 | synchronized (FgThread.class) { |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 49 | ensureThreadLocked(); |
| 50 | return sInstance; |
| 51 | } |
| 52 | } |
| 53 | |
| 54 | public static Handler getHandler() { |
yangbingqian | 6ecf9af | 2017-05-10 20:31:15 +0800 | [diff] [blame] | 55 | synchronized (FgThread.class) { |
Dianne Hackborn | 8d044e8 | 2013-04-30 17:24:15 -0700 | [diff] [blame] | 56 | ensureThreadLocked(); |
| 57 | return sHandler; |
| 58 | } |
| 59 | } |
| 60 | } |