HdmiCecMessageCache.java revision e81e108c4035ea8933525baa8108cb392f8abf5d 
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.HdmiCec;
20import android.hardware.hdmi.HdmiCecMessage;
21import android.util.FastImmutableArraySet;
22import android.util.SparseArray;
23
24/**
25 * Cache for incoming message. It caches {@link HdmiCecMessage} with source address and opcode
26 * as a key.
27 *
28 * <p>Note that whenever a device is removed it should call {@link #flushMessagesFrom(int)}
29 * to clean up messages come from the device.
30 */
31final class HdmiCecMessageCache {
32    private static final FastImmutableArraySet<Integer> CACHEABLE_OPCODES = new FastImmutableArraySet<>(
33            new Integer[] {
34                    HdmiCec.MESSAGE_SET_OSD_NAME,
35                    HdmiCec.MESSAGE_REPORT_PHYSICAL_ADDRESS,
36                    HdmiCec.MESSAGE_DEVICE_VENDOR_ID,
37                    HdmiCec.MESSAGE_CEC_VERSION,
38            });
39
40    // It's like [Source Logical Address, [Opcode, HdmiCecMessage]].
41    private final SparseArray<SparseArray<HdmiCecMessage>> mCache = new SparseArray<>();
42
43    HdmiCecMessageCache() {
44    }
45
46    /**
47     * Return a {@link HdmiCecMessage} corresponding to the given {@code address} and
48     * {@code opcode}.
49     *
50     * @param address a logical address of source device
51     * @param opcode opcode of message
52     * @return null if has no {@link HdmiCecMessage} matched to the given {@code address} and {code
53     *         opcode}
54     */
55    public HdmiCecMessage getMessage(int address, int opcode) {
56        SparseArray<HdmiCecMessage> messages = mCache.get(address);
57        if (messages == null) {
58            return null;
59        }
60
61        return messages.get(opcode);
62    }
63
64    /**
65     * Flush all {@link HdmiCecMessage}s sent from the given {@code address}.
66     *
67     * @param address a logical address of source device
68     */
69    public void flushMessagesFrom(int address) {
70        mCache.remove(address);
71    }
72
73    /**
74     * Flush all cached {@link HdmiCecMessage}s.
75     */
76    public void flushAll() {
77        mCache.clear();
78    }
79
80    /**
81     * Cache incoming {@link HdmiCecMessage}. If opcode of message is not listed on
82     * cacheable opcodes list, just ignore it.
83     *
84     * @param message a {@link HdmiCecMessage} to be cached
85     */
86    public void cacheMessage(HdmiCecMessage message) {
87        int opcode = message.getOpcode();
88        if (!isCacheable(opcode)) {
89            return;
90        }
91
92        int source = message.getSource();
93        SparseArray<HdmiCecMessage> messages = mCache.get(source);
94        if (messages == null) {
95            messages = new SparseArray<>();
96            mCache.put(source, messages);
97        }
98        messages.put(opcode, message);
99    }
100
101    private boolean isCacheable(int opcode) {
102        return CACHEABLE_OPCODES.contains(opcode);
103    }
104}
105