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1 /*
2  * Copyright (C) 2020 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.hdmi;
18 
19 import java.util.ArrayList;
20 import java.util.List;
21 
22 /**
23  * Buffer for processing the incoming CEC messages while allocating logical addresses.
24  */
25 final class CecMessageBuffer {
26     private List<HdmiCecMessage> mBuffer = new ArrayList<>();
27     private HdmiControlService mHdmiControlService;
28 
CecMessageBuffer(HdmiControlService hdmiControlService)29     CecMessageBuffer(HdmiControlService hdmiControlService) {
30         mHdmiControlService = hdmiControlService;
31     }
32 
33     /**
34      * Adds a message to the buffer.
35      * Only certain types of messages need to be buffered.
36      * @param message The message to add to the buffer
37      * @return Whether the message was added to the buffer
38      */
bufferMessage(HdmiCecMessage message)39     public boolean bufferMessage(HdmiCecMessage message) {
40         switch (message.getOpcode()) {
41             case Constants.MESSAGE_ACTIVE_SOURCE:
42                 bufferActiveSource(message);
43                 return true;
44             case Constants.MESSAGE_IMAGE_VIEW_ON:
45             case Constants.MESSAGE_TEXT_VIEW_ON:
46                 bufferImageOrTextViewOn(message);
47                 return true;
48             case Constants.MESSAGE_SYSTEM_AUDIO_MODE_REQUEST:
49                 bufferSystemAudioModeRequest(message);
50                 return true;
51             // Add here if new message that needs to buffer
52             default:
53                 // Do not need to buffer messages other than above
54                 return false;
55         }
56     }
57 
58     /**
59      * Process all messages in the buffer.
60      */
processMessages()61     public void processMessages() {
62         for (final HdmiCecMessage message : mBuffer) {
63             mHdmiControlService.runOnServiceThread(new Runnable() {
64                 @Override
65                 public void run() {
66                     mHdmiControlService.handleCecCommand(message);
67                 }
68             });
69         }
70         mBuffer.clear();
71     }
72 
bufferActiveSource(HdmiCecMessage message)73     private void bufferActiveSource(HdmiCecMessage message) {
74         if (!replaceMessageIfBuffered(message, Constants.MESSAGE_ACTIVE_SOURCE)) {
75             mBuffer.add(message);
76         }
77     }
78 
bufferImageOrTextViewOn(HdmiCecMessage message)79     private void bufferImageOrTextViewOn(HdmiCecMessage message) {
80         if (!replaceMessageIfBuffered(message, Constants.MESSAGE_IMAGE_VIEW_ON)
81                 && !replaceMessageIfBuffered(message, Constants.MESSAGE_TEXT_VIEW_ON)) {
82             mBuffer.add(message);
83         }
84     }
85 
bufferSystemAudioModeRequest(HdmiCecMessage message)86     private void bufferSystemAudioModeRequest(HdmiCecMessage message) {
87         if (!replaceMessageIfBuffered(message, Constants.MESSAGE_SYSTEM_AUDIO_MODE_REQUEST)) {
88             mBuffer.add(message);
89         }
90     }
91 
92     // Returns true if the message is replaced
replaceMessageIfBuffered(HdmiCecMessage message, int opcode)93     private boolean replaceMessageIfBuffered(HdmiCecMessage message, int opcode) {
94         for (int i = 0; i < mBuffer.size(); i++) {
95             HdmiCecMessage bufferedMessage = mBuffer.get(i);
96             if (bufferedMessage.getOpcode() == opcode) {
97                 mBuffer.set(i, message);
98                 return true;
99             }
100         }
101         return false;
102     }
103 }
104