1 /* 2 * Copyright (C) 2012 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.power; 18 19 /** 20 * Low-level screen on blocker mechanism which is used to keep the screen off 21 * or the contents of the screen hidden until the window manager is ready to show new content. 22 */ 23 interface ScreenOnBlocker { 24 /** 25 * Acquires the screen on blocker. 26 * Prevents the screen from turning on. 27 * 28 * Calls to acquire() nest and must be matched by the same number 29 * of calls to release(). 30 */ acquire()31 void acquire(); 32 33 /** 34 * Releases the screen on blocker. 35 * Allows the screen to turn on. 36 * 37 * It is an error to call release() if the screen on blocker has not been acquired. 38 * The system may crash. 39 */ release()40 void release(); 41 } 42