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.display; 18 19 import android.content.Context; 20 import android.os.Handler; 21 22 import java.io.PrintWriter; 23 24 /** 25 * A display adapter makes zero or more display devices available to the system 26 * and provides facilities for discovering when displays are connected or disconnected. 27 * <p> 28 * For now, all display adapters are registered in the system server but 29 * in principle it could be done from other processes. 30 * </p><p> 31 * Display adapters are guarded by the {@link DisplayManagerService.SyncRoot} lock. 32 * </p> 33 */ 34 abstract class DisplayAdapter { 35 private final DisplayManagerService.SyncRoot mSyncRoot; 36 private final Context mContext; 37 private final Handler mHandler; 38 private final Listener mListener; 39 private final String mName; 40 41 public static final int DISPLAY_DEVICE_EVENT_ADDED = 1; 42 public static final int DISPLAY_DEVICE_EVENT_CHANGED = 2; 43 public static final int DISPLAY_DEVICE_EVENT_REMOVED = 3; 44 45 // Called with SyncRoot lock held. DisplayAdapter(DisplayManagerService.SyncRoot syncRoot, Context context, Handler handler, Listener listener, String name)46 public DisplayAdapter(DisplayManagerService.SyncRoot syncRoot, 47 Context context, Handler handler, Listener listener, String name) { 48 mSyncRoot = syncRoot; 49 mContext = context; 50 mHandler = handler; 51 mListener = listener; 52 mName = name; 53 } 54 55 /** 56 * Gets the object that the display adapter should synchronize on when handling 57 * calls that come in from outside of the display manager service. 58 */ getSyncRoot()59 public final DisplayManagerService.SyncRoot getSyncRoot() { 60 return mSyncRoot; 61 } 62 63 /** 64 * Gets the display adapter's context. 65 */ getContext()66 public final Context getContext() { 67 return mContext; 68 } 69 70 /** 71 * Gets a handler that the display adapter may use to post asynchronous messages. 72 */ getHandler()73 public final Handler getHandler() { 74 return mHandler; 75 } 76 77 /** 78 * Gets the display adapter name for debugging purposes. 79 */ getName()80 public final String getName() { 81 return mName; 82 } 83 84 /** 85 * Registers the display adapter with the display manager. 86 * 87 * The display adapter should register any built-in display devices as soon as possible. 88 * The boot process will wait for the default display to be registered. 89 * Other display devices can be registered dynamically later. 90 */ registerLocked()91 public void registerLocked() { 92 } 93 94 /** 95 * Dumps the local state of the display adapter. 96 */ dumpLocked(PrintWriter pw)97 public void dumpLocked(PrintWriter pw) { 98 } 99 100 /** 101 * Sends a display device event to the display adapter listener asynchronously. 102 */ sendDisplayDeviceEventLocked( final DisplayDevice device, final int event)103 protected final void sendDisplayDeviceEventLocked( 104 final DisplayDevice device, final int event) { 105 mHandler.post(new Runnable() { 106 @Override 107 public void run() { 108 mListener.onDisplayDeviceEvent(device, event); 109 } 110 }); 111 } 112 113 /** 114 * Sends a request to perform traversals. 115 */ sendTraversalRequestLocked()116 protected final void sendTraversalRequestLocked() { 117 mHandler.post(new Runnable() { 118 @Override 119 public void run() { 120 mListener.onTraversalRequested(); 121 } 122 }); 123 } 124 125 public interface Listener { onDisplayDeviceEvent(DisplayDevice device, int event)126 public void onDisplayDeviceEvent(DisplayDevice device, int event); onTraversalRequested()127 public void onTraversalRequested(); 128 } 129 } 130