content: /*
   * Copyright (C) 2014 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.android.server.hdmi;
  
  import android.util.FastImmutableArraySet;
  import android.util.SparseArray;
  
  /**
   * Cache for incoming message. It caches {@link HdmiCecMessage} with source address and opcode
   * as a key.
   *
   * <p>Note that whenever a device is removed it should call {@link #flushMessagesFrom(int)}
   * to clean up messages come from the device.
   */
  final class HdmiCecMessageCache {
      private static final FastImmutableArraySet<Integer> CACHEABLE_OPCODES =
              new FastImmutableArraySet<>(new Integer[] {
                      Constants.MESSAGE_SET_OSD_NAME,
                      Constants.MESSAGE_REPORT_PHYSICAL_ADDRESS,
                      Constants.MESSAGE_DEVICE_VENDOR_ID,
                      Constants.MESSAGE_CEC_VERSION,
              });
  
      // It's like [Source Logical Address, [Opcode, HdmiCecMessage]].
      private final SparseArray<SparseArray<HdmiCecMessage>> mCache = new SparseArray<>();
  
      HdmiCecMessageCache() {
      }
  
      /**
       * Return a {@link HdmiCecMessage} corresponding to the given {@code address} and
       * {@code opcode}.
       *
       * @param address a logical address of source device
       * @param opcode opcode of message
       * @return null if has no {@link HdmiCecMessage} matched to the given {@code address} and {code
       *         opcode}
       */
      public HdmiCecMessage getMessage(int address, int opcode) {
          SparseArray<HdmiCecMessage> messages = mCache.get(address);
          if (messages == null) {
              return null;
          }
  
          return messages.get(opcode);
      }
  
      /**
       * Flush all {@link HdmiCecMessage}s sent from the given {@code address}.
       *
       * @param address a logical address of source device
       */
      public void flushMessagesFrom(int address) {
          mCache.remove(address);
      }
  
      /**
       * Flush all cached {@link HdmiCecMessage}s.
       */
      public void flushAll() {
          mCache.clear();
      }
  
      /**
       * Cache incoming {@link HdmiCecMessage}. If opcode of message is not listed on
       * cacheable opcodes list, just ignore it.
       *
       * @param message a {@link HdmiCecMessage} to be cached
       */
      public void cacheMessage(HdmiCecMessage message) {
          int opcode = message.getOpcode();
          if (!isCacheable(opcode)) {
              return;
          }
  
          int source = message.getSource();
          SparseArray<HdmiCecMessage> messages = mCache.get(source);
          if (messages == null) {
              messages = new SparseArray<>();
              mCache.put(source, messages);
          }
          messages.put(opcode, message);
      }
  
      private boolean isCacheable(int opcode) {
          return CACHEABLE_OPCODES.contains(opcode);
      }
  }
  