import com.google.ipc.invalidation.common.CommonInvalidationConstants2; //导入依赖的package包/类
/** Returns the header to include on a message to the server. */
private ClientHeader.Builder createClientHeader() {
  Preconditions.checkState(internalScheduler.isRunningOnThread(), "Not on internal thread");
  ClientHeader.Builder builder = ClientHeader.newBuilder()
      .setProtocolVersion(CommonInvalidationConstants2.PROTOCOL_VERSION)
      .setClientTimeMs(internalScheduler.getCurrentTimeMs())
      .setMessageId(Integer.toString(messageId))
      .setMaxKnownServerTimeMs(lastKnownServerTimeMs)
      .setRegistrationSummary(listener.getRegistrationSummary())
      .setClientType(clientType);
  ByteString clientToken = listener.getClientToken();
  if (clientToken != null) {
    logger.fine("Sending token on client->server message: %s",
        CommonProtoStrings2.toLazyCompactString(clientToken));
    builder.setClientToken(clientToken);
  }
  return builder;
}
 

import com.google.ipc.invalidation.common.CommonInvalidationConstants2; //导入依赖的package包/类
/** Returns a default config builder for the client. */
public static ClientConfigP.Builder createConfig() {
  return ClientConfigP.newBuilder()
      .setVersion(CommonProtos2.newVersion(CommonInvalidationConstants2.CONFIG_MAJOR_VERSION,
          CommonInvalidationConstants2.CONFIG_MINOR_VERSION))
      .setProtocolHandlerConfig(ProtocolHandler.createConfig());
}
 

import com.google.ipc.invalidation.common.CommonInvalidationConstants2; //导入依赖的package包/类
/** Returns a configuration builder with parameters set for unit tests. */
public static ClientConfigP.Builder createConfigForTest() {
  return ClientConfigP.newBuilder()
      .setVersion(CommonProtos2.newVersion(CommonInvalidationConstants2.CONFIG_MAJOR_VERSION,
          CommonInvalidationConstants2.CONFIG_MINOR_VERSION))
      .setProtocolHandlerConfig(ProtocolHandler.createConfigForTest())
      .setNetworkTimeoutDelayMs(2 * 1000)
      .setHeartbeatIntervalMs(5 * 1000)
      .setWriteRetryDelayMs(500);
}
 

import com.google.ipc.invalidation.common.CommonInvalidationConstants2; //导入依赖的package包/类
/**
 * Handles a message from the server. If the message can be processed (i.e., is valid, is
 * of the right version, and is not a silence message), returns a {@link ParsedMessage}
 * representing it. Otherwise, returns {@code null}.
 * <p>
 * This class intercepts and processes silence messages. In this case, it will discard any other
 * data in the message.
 * <p>
 * Note that this method does <b>not</b> check the session token of any message.
 */
ParsedMessage handleIncomingMessage(byte[] incomingMessage) {
  Preconditions.checkState(internalScheduler.isRunningOnThread(), "Not on internal thread");
  ServerToClientMessage message;
  try {
    message = ServerToClientMessage.parseFrom(incomingMessage);
  } catch (InvalidProtocolBufferException exception) {
    logger.warning("Incoming message is unparseable: %s",
        CommonProtoStrings2.toLazyCompactString(incomingMessage));
    return null;
  }

  // Validate the message. If this passes, we can blindly assume valid messages from here on.
  logger.fine("Incoming message: %s", message);
  if (!msgValidator.isValid(message)) {
    statistics.recordError(ClientErrorType.INCOMING_MESSAGE_FAILURE);
    logger.severe("Received invalid message: %s", message);
    return null;
  }

  // Check the version of the message.
  if (message.getHeader().getProtocolVersion().getVersion().getMajorVersion() !=
      CommonInvalidationConstants2.PROTOCOL_MAJOR_VERSION) {
    statistics.recordError(ClientErrorType.PROTOCOL_VERSION_FAILURE);
    logger.severe("Dropping message with incompatible version: %s", message);
    return null;
  }

  // Check if it is a ConfigChangeMessage which indicates that messages should no longer be
  // sent for a certain duration. Perform this check before the token is even checked.
  if (message.hasConfigChangeMessage()) {
    ConfigChangeMessage configChangeMsg = message.getConfigChangeMessage();
    statistics.recordReceivedMessage(ReceivedMessageType.CONFIG_CHANGE);
    if (configChangeMsg.hasNextMessageDelayMs()) {  // Validator has ensured that it is positive.
      nextMessageSendTimeMs =
          internalScheduler.getCurrentTimeMs() + configChangeMsg.getNextMessageDelayMs();
    }
    return null;  // Ignore all other messages in the envelope.
  }

  lastKnownServerTimeMs = Math.max(lastKnownServerTimeMs, message.getHeader().getServerTimeMs());
  return new ParsedMessage(message);
}