/*
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* Copyright 2014 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package chat.server.moquette;
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import chat.server.moquette.message.MqttFixedHeader;
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import chat.server.moquette.message.MqttQoS;
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import io.netty.handler.codec.DecoderException;
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final class MqttCodecUtil {
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private static final char[] TOPIC_WILDCARDS = {'#', '+'};
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private static final int MIN_CLIENT_ID_LENGTH = 1;
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private static final int MAX_CLIENT_ID_LENGTH = 23;
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static boolean isValidPublishTopicName(String topicName) {
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// publish topic name must not contain any wildcard
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for (char c : TOPIC_WILDCARDS) {
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if (topicName.indexOf(c) >= 0) {
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return false;
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}
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}
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return true;
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}
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static boolean isValidMessageId(int messageId) {
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return messageId != 0;
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}
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public static boolean isValidClientId(MqttVersion mqttVersion, String clientId) {
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if (mqttVersion == MqttVersion.MQTT_3_1) {
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return clientId != null && clientId.length() >= MIN_CLIENT_ID_LENGTH &&
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clientId.length() <= MAX_CLIENT_ID_LENGTH;
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}
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if (mqttVersion.protocolLevel() >= MqttVersion.MQTT_3_1_1.protocolLevel()) {
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// In 3.1.3.1 Client Identifier of MQTT 3.1.1 specification, The Server MAY allow ClientId’s
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// that contain more than 23 encoded bytes. And, The Server MAY allow zero-length ClientId.
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return clientId != null;
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}
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throw new IllegalArgumentException(mqttVersion + " is unknown mqtt version");
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}
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static MqttFixedHeader validateFixedHeader(MqttFixedHeader mqttFixedHeader) {
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switch (mqttFixedHeader.messageType()) {
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case PUBREL:
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case SUBSCRIBE:
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case UNSUBSCRIBE:
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if (mqttFixedHeader.qosLevel() != MqttQoS.AT_LEAST_ONCE) {
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throw new DecoderException(mqttFixedHeader.messageType().name() + " message must have QoS 1");
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}
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default:
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return mqttFixedHeader;
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}
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}
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static MqttFixedHeader resetUnusedFields(MqttFixedHeader mqttFixedHeader) {
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switch (mqttFixedHeader.messageType()) {
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case CONNECT:
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case CONNACK:
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case PUBACK:
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case PUBREC:
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case PUBCOMP:
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case SUBACK:
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case UNSUBACK:
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case PINGREQ:
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case PINGRESP:
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//case DISCONNECT:
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if (mqttFixedHeader.isDup() ||
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mqttFixedHeader.qosLevel() != MqttQoS.AT_MOST_ONCE ||
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mqttFixedHeader.isRetain()) {
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return new MqttFixedHeader(
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mqttFixedHeader.messageType(),
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false,
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MqttQoS.AT_MOST_ONCE,
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false,
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mqttFixedHeader.remainingLength());
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}
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return mqttFixedHeader;
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case PUBREL:
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case SUBSCRIBE:
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case UNSUBSCRIBE:
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if (mqttFixedHeader.isRetain()) {
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return new MqttFixedHeader(
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mqttFixedHeader.messageType(),
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mqttFixedHeader.isDup(),
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mqttFixedHeader.qosLevel(),
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false,
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mqttFixedHeader.remainingLength());
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}
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return mqttFixedHeader;
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default:
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return mqttFixedHeader;
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}
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}
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private MqttCodecUtil() { }
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}
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