DelayedMessageBuffer.java revision ad1e3d7df42376cd2a257b6c3b2fed540658a6e3 
1/*
2 * Copyright (C) 2014 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.hdmi;
18
19import android.hardware.hdmi.HdmiDeviceInfo;
20import android.util.Slog;
21
22import java.util.ArrayList;
23import java.util.Iterator;
24
25/**
26 * Buffer storage to keep incoming messages for later processing. Used to
27 * handle messages that arrive when the device is not ready. Useful when
28 * keeping the messages from a connected device which are not discovered yet.
29 */
30final class DelayedMessageBuffer {
31    private final ArrayList<HdmiCecMessage> mBuffer = new ArrayList<>();
32    private final HdmiCecLocalDevice mDevice;
33
34    DelayedMessageBuffer(HdmiCecLocalDevice device) {
35        mDevice = device;
36    }
37
38    /**
39     * Add a new message to the buffer. The buffer keeps selected messages in
40     * the order they are received.
41     *
42     * @param message {@link HdmiCecMessage} to add
43     */
44    void add(HdmiCecMessage message) {
45        boolean buffered = true;
46
47        // Note that all the messages are not handled in the same manner.
48        // For &lt;Active Source&gt; we keep the latest one only.
49        // TODO: This might not be the best way to choose the active source.
50        //       Devise a better way to pick up the best one.
51        switch (message.getOpcode()) {
52            case Constants.MESSAGE_ACTIVE_SOURCE:
53                removeActiveSource();
54                mBuffer.add(message);
55                break;
56            case Constants.MESSAGE_INITIATE_ARC:
57            case Constants.MESSAGE_SET_SYSTEM_AUDIO_MODE:
58                mBuffer.add(message);
59                break;
60            default:
61                buffered = false;
62                break;
63        }
64        if (buffered) {
65            HdmiLogger.debug("Buffering message:" + message);
66        }
67    }
68
69    private void removeActiveSource() {
70        // Uses iterator to remove elements while looping through the list.
71        for (Iterator<HdmiCecMessage> iter = mBuffer.iterator(); iter.hasNext(); ) {
72            HdmiCecMessage message = iter.next();
73            if (message.getOpcode() == Constants.MESSAGE_ACTIVE_SOURCE) {
74                iter.remove();
75            }
76        }
77    }
78
79    void processAllMessages() {
80        for (HdmiCecMessage message : mBuffer) {
81            mDevice.onMessage(message);
82            HdmiLogger.debug("Processing message:" + message);
83        }
84        mBuffer.clear();
85    }
86
87    /**
88     * Process messages from a given logical device. Called by
89     * {@link NewDeviceAction} actions when they finish adding the device
90     * information.
91     * <p>&lt;Active Source&gt; is not processed in this method but processed
92     * separately via {@link #processActiveSource()}.
93     *
94     * @param address logical address of CEC device which the messages to process
95     *        are associated with
96     */
97    void processMessagesForDevice(int address) {
98        HdmiLogger.debug("Processing message for address:" + address);
99        for (Iterator<HdmiCecMessage> iter = mBuffer.iterator(); iter.hasNext(); ) {
100            HdmiCecMessage message = iter.next();
101            if (message.getOpcode() == Constants.MESSAGE_ACTIVE_SOURCE) {
102                continue;
103            }
104            if (message.getSource() == address) {
105                mDevice.onMessage(message);
106                HdmiLogger.debug("Processing message:" + message);
107                iter.remove();
108            }
109        }
110    }
111
112    /**
113     * Process &lt;Active Source&gt;.
114     *
115     * <p>The message has a dependency on TV input framework. Should be invoked
116     * after we get the callback
117     * {@link android.media.tv.TvInputManager.TvInputCallback#onInputAdded(String)}
118     * to ensure the processing of the message takes effect when transformed
119     * to input change callback.
120     *
121     * @param address logical address of the device to be the active source
122     */
123    void processActiveSource(int address) {
124        for (Iterator<HdmiCecMessage> iter = mBuffer.iterator(); iter.hasNext(); ) {
125            HdmiCecMessage message = iter.next();
126            if (message.getOpcode() == Constants.MESSAGE_ACTIVE_SOURCE
127                    && message.getSource() == address) {
128                mDevice.onMessage(message);
129                HdmiLogger.debug("Processing message:" + message);
130                iter.remove();
131            }
132        }
133    }
134}
135