DelayedMessageBuffer.java revision 7fa3a66470d2133796defd14a0600578758882ac 
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                mBuffer.add(message);
58                break;
59            default:
60                buffered = false;
61                break;
62        }
63        if (buffered) {
64            HdmiLogger.debug("Buffering message:" + message);
65        }
66    }
67
68    private void removeActiveSource() {
69        // Uses iterator to remove elements while looping through the list.
70        for (Iterator<HdmiCecMessage> iter = mBuffer.iterator(); iter.hasNext(); ) {
71            HdmiCecMessage message = iter.next();
72            if (message.getOpcode() == Constants.MESSAGE_ACTIVE_SOURCE) {
73                iter.remove();
74            }
75        }
76    }
77
78    void processAllMessages() {
79        for (HdmiCecMessage message : mBuffer) {
80            mDevice.onMessage(message);
81            HdmiLogger.debug("Processing message:" + message);
82        }
83        mBuffer.clear();
84    }
85
86    /**
87     * Process messages from a given logical device. Called by
88     * {@link NewDeviceAction} actions when they finish adding the device
89     * information.
90     * <p>&lt;Active Source&gt; is not processed in this method but processed
91     * separately via {@link #processActiveSource()}.
92     *
93     * @param address logical address of CEC device which the messages to process
94     *        are associated with
95     */
96    void processMessagesForDevice(int address) {
97        HdmiLogger.debug("Processing message for address:" + address);
98        for (Iterator<HdmiCecMessage> iter = mBuffer.iterator(); iter.hasNext(); ) {
99            HdmiCecMessage message = iter.next();
100            if (message.getOpcode() == Constants.MESSAGE_ACTIVE_SOURCE) {
101                continue;
102            }
103            if (message.getSource() == address) {
104                mDevice.onMessage(message);
105                HdmiLogger.debug("Processing message:" + message);
106                iter.remove();
107            }
108        }
109    }
110
111    /**
112     * Process &lt;Active Source&gt;.
113     *
114     * <p>The message has a dependency on TV input framework. Should be invoked
115     * after we get the callback
116     * {@link android.media.tv.TvInputManager.TvInputCallback#onInputAdded(String)}
117     * to ensure the processing of the message takes effect when transformed
118     * to input change callback.
119     *
120     * @param address logical address of the device to be the active source
121     */
122    void processActiveSource(int address) {
123        for (Iterator<HdmiCecMessage> iter = mBuffer.iterator(); iter.hasNext(); ) {
124            HdmiCecMessage message = iter.next();
125            if (message.getOpcode() == Constants.MESSAGE_ACTIVE_SOURCE
126                    && message.getSource() == address) {
127                mDevice.onMessage(message);
128                HdmiLogger.debug("Processing message:" + message);
129                iter.remove();
130            }
131        }
132    }
133}
134