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
17package com.android.server.display;
18
19import android.content.Context;
20import android.os.Handler;
21import android.view.Display;
22
23import java.io.PrintWriter;
24import java.util.concurrent.atomic.AtomicInteger;
25
26/**
27 * A display adapter makes zero or more display devices available to the system
28 * and provides facilities for discovering when displays are connected or disconnected.
29 * <p>
30 * For now, all display adapters are registered in the system server but
31 * in principle it could be done from other processes.
32 * </p><p>
33 * Display adapters are guarded by the {@link DisplayManagerService.SyncRoot} lock.
34 * </p>
35 */
36abstract class DisplayAdapter {
37    private final DisplayManagerService.SyncRoot mSyncRoot;
38    private final Context mContext;
39    private final Handler mHandler;
40    private final Listener mListener;
41    private final String mName;
42
43    public static final int DISPLAY_DEVICE_EVENT_ADDED = 1;
44    public static final int DISPLAY_DEVICE_EVENT_CHANGED = 2;
45    public static final int DISPLAY_DEVICE_EVENT_REMOVED = 3;
46
47    /**
48     * Used to generate globally unique display mode ids.
49     */
50    private static final AtomicInteger NEXT_DISPLAY_MODE_ID = new AtomicInteger(1);  // 0 = no mode.
51
52    // Called with SyncRoot lock held.
53    public DisplayAdapter(DisplayManagerService.SyncRoot syncRoot,
54            Context context, Handler handler, Listener listener, String name) {
55        mSyncRoot = syncRoot;
56        mContext = context;
57        mHandler = handler;
58        mListener = listener;
59        mName = name;
60    }
61
62    /**
63     * Gets the object that the display adapter should synchronize on when handling
64     * calls that come in from outside of the display manager service.
65     */
66    public final DisplayManagerService.SyncRoot getSyncRoot() {
67        return mSyncRoot;
68    }
69
70    /**
71     * Gets the display adapter's context.
72     */
73    public final Context getContext() {
74        return mContext;
75    }
76
77    /**
78     * Gets a handler that the display adapter may use to post asynchronous messages.
79     */
80    public final Handler getHandler() {
81        return mHandler;
82    }
83
84    /**
85     * Gets the display adapter name for debugging purposes.
86     */
87    public final String getName() {
88        return mName;
89    }
90
91    /**
92     * Registers the display adapter with the display manager.
93     *
94     * The display adapter should register any built-in display devices as soon as possible.
95     * The boot process will wait for the default display to be registered.
96     * Other display devices can be registered dynamically later.
97     */
98    public void registerLocked() {
99    }
100
101    /**
102     * Dumps the local state of the display adapter.
103     */
104    public void dumpLocked(PrintWriter pw) {
105    }
106
107    /**
108     * Sends a display device event to the display adapter listener asynchronously.
109     */
110    protected final void sendDisplayDeviceEventLocked(
111            final DisplayDevice device, final int event) {
112        mHandler.post(new Runnable() {
113            @Override
114            public void run() {
115                mListener.onDisplayDeviceEvent(device, event);
116            }
117        });
118    }
119
120    /**
121     * Sends a request to perform traversals.
122     */
123    protected final void sendTraversalRequestLocked() {
124        mHandler.post(new Runnable() {
125            @Override
126            public void run() {
127                mListener.onTraversalRequested();
128            }
129        });
130    }
131
132    public static Display.Mode createMode(int width, int height, float refreshRate) {
133        return new Display.Mode(
134                NEXT_DISPLAY_MODE_ID.getAndIncrement(), width, height, refreshRate);
135    }
136
137    public interface Listener {
138        public void onDisplayDeviceEvent(DisplayDevice device, int event);
139        public void onTraversalRequested();
140    }
141}
142