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      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 
     17 package com.android.server.hdmi;
     18 
     19 import android.util.FastImmutableArraySet;
     20 import 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  */
     29 final 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