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