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HiveMQ MQTT Client is an MQTT 5.0 and MQTT 3.1.1 compatible and feature-rich high-performance Java client library with different API flavours and backpressure support
/*
* Copyright 2018 dc-square and the HiveMQ MQTT Client 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.hivemq.client.internal.mqtt.codec.encoder.mqtt5;
import com.hivemq.client.internal.mqtt.codec.encoder.MqttEncoderContext;
import com.hivemq.client.internal.mqtt.codec.encoder.MqttMessageEncoder;
import com.hivemq.client.internal.mqtt.datatypes.MqttVariableByteInteger;
import com.hivemq.client.internal.mqtt.message.MqttMessage;
import com.hivemq.client.internal.mqtt.message.MqttMessageWithUserProperties;
import com.hivemq.client.mqtt.mqtt5.message.Mqtt5ReasonCode;
import io.netty.buffer.ByteBuf;
import org.jetbrains.annotations.NotNull;
import static com.hivemq.client.internal.mqtt.codec.encoder.MqttMessageEncoderUtil.*;
import static com.hivemq.client.internal.mqtt.codec.encoder.mqtt5.Mqtt5MessageEncoderUtil.encodeNullableProperty;
import static com.hivemq.client.internal.mqtt.codec.encoder.mqtt5.Mqtt5MessageEncoderUtil.nullablePropertyEncodedLength;
import static com.hivemq.client.internal.mqtt.message.MqttProperty.REASON_STRING;
/**
* Base class of encoders for MQTT messages with omissible User Properties.
*
* @author Silvio Giebl
*/
abstract class Mqtt5MessageWithUserPropertiesEncoder
extends MqttMessageEncoder {
@Override
protected @NotNull ByteBuf encode(final @NotNull M message, final @NotNull MqttEncoderContext context) {
int propertyLength = propertyLength(message);
final int remainingLengthWithoutProperties = remainingLengthWithoutProperties(message);
int remainingLength = remainingLength(message, remainingLengthWithoutProperties, propertyLength);
int encodedLength = encodedPacketLength(remainingLength);
int omittedProperties = 0;
while (encodedLength > context.getMaximumPacketSize()) {
omittedProperties++;
propertyLength = propertyLength(message, propertyLength, omittedProperties);
if (propertyLength < 0) {
throw maximumPacketSizeExceeded(message, encodedLength, context.getMaximumPacketSize());
}
remainingLength = remainingLength(message, remainingLengthWithoutProperties, propertyLength);
encodedLength = encodedPacketLength(remainingLength);
}
return encode(message, context, encodedLength, remainingLength, propertyLength, omittedProperties);
}
/**
* Encodes the given MQTT message.
*
* @param message the MQTT message to encode.
* @param context the encoder context.
* @param encodedLength the encoded length the MQTT message.
* @param remainingLength the remaining length of the MQTT message.
* @param propertyLength the property length of the MQTT message.
* @param omittedProperties the count of omitted properties of the MQTT message.
* @return the byte buffer the MQTT message is encoded to.
*/
@NotNull ByteBuf encode(
final @NotNull M message, final @NotNull MqttEncoderContext context, final int encodedLength,
final int remainingLength, final int propertyLength, final int omittedProperties) {
final ByteBuf out = context.getAllocator().ioBuffer(encodedLength, encodedLength);
encode(message, out, remainingLength, propertyLength, omittedProperties);
return out;
}
/**
* Encodes the given MQTT message.
*
* @param message the MQTT message to encode.
* @param out the byte buffer the MQTT message is encoded to.
* @param remainingLength the remaining length of the MQTT message.
* @param propertyLength the property length of the MQTT message.
* @param omittedProperties the count of omitted properties of the MQTT message.
*/
abstract void encode(
final @NotNull M message, final @NotNull ByteBuf out, final int remainingLength, final int propertyLength,
final int omittedProperties);
/**
* Calculates the remaining length of the given MQTT message.
*
* @param message the MQTT message to encode.
* @param remainingLengthWithoutProperties the already calculated remaining length without the properties.
* @param propertyLength the already calculated property length.
* @return the remaining length of the MQTT message.
*/
private int remainingLength(
final @NotNull M message, final int remainingLengthWithoutProperties, final int propertyLength) {
return remainingLengthWithoutProperties + propertyLengthWithHeader(message, propertyLength);
}
/**
* Calculates the remaining length without the properties of the given MQTT message.
*
* @param message the MQTT message to encode.
* @return the remaining length without the properties of the MQTT message.
*/
abstract int remainingLengthWithoutProperties(final @NotNull M message);
/**
* Calculates the property length of the given MQTT message.
*
* @param message the MQTT message to encode.
* @return the property length of the MQTT message.
*/
abstract int propertyLength(final @NotNull M message);
/**
* Calculates the property length of the given MQTT message with omitting the given count of properties.
*
* @param message the MQTT message to encode.
* @param propertyLength the already calculated property length with a count of omitted properties of {@code
* omittedProperties - 1}.
* @param omittedProperties the count of omitted properties.
* @return the property length of the MQTT message with omitting the given count of properties or -1 if no more
* properties can be omitted.
*/
int propertyLength(final @NotNull M message, final int propertyLength, final int omittedProperties) {
switch (omittedProperties) {
case 0:
return propertyLength;
case 1:
return propertyLength - message.getUserProperties().encodedLength();
default:
return -1;
}
}
/**
* Calculates the encoded length of the properties of the given MQTT message with a prefixed header.
*
* @param message the MQTT message to encode.
* @param propertyLength the already calculated property length.
* @return the encoded length of the properties of the MQTT message with a prefixed header.
*/
int propertyLengthWithHeader(final @NotNull M message, final int propertyLength) {
return encodedLengthWithHeader(propertyLength);
}
/**
* Calculates the encoded length of omissible properties of the given MQTT message.
*
* @param message the MQTT message to encode.
* @return the encoded length of the omissible properties of the MQTT message.
*/
int omissiblePropertyLength(final @NotNull M message) {
return message.getUserProperties().encodedLength();
}
/**
* Encodes the omissible properties of the given MQTT message if they must not be omitted due to the given count of
* omitted properties.
*
* @param message the MQTT message to encode.
* @param out the byte buffer to encode to.
* @param omittedProperties the count of properties of the MQTT message.
*/
void encodeOmissibleProperties(final @NotNull M message, final @NotNull ByteBuf out, final int omittedProperties) {
if (omittedProperties == 0) {
message.getUserProperties().encode(out);
}
}
/**
* Base class of encoders for MQTT messages with an omissible Reason String and omissible User Properties.
*/
static abstract class WithReason
extends Mqtt5MessageWithUserPropertiesEncoder {
@Override
int propertyLength(final @NotNull M message, final int propertyLength, final int omittedProperties) {
switch (omittedProperties) {
case 0:
return propertyLength;
case 1:
return propertyLength - reasonStringLength(message);
case 2:
return propertyLength - message.getUserProperties().encodedLength();
default:
return -1;
}
}
@Override
final int omissiblePropertyLength(final @NotNull M message) {
return reasonStringLength(message) + message.getUserProperties().encodedLength();
}
@Override
void encodeOmissibleProperties(
final @NotNull M message, final @NotNull ByteBuf out, final int omittedProperties) {
if (omittedProperties == 0) {
encodeNullableProperty(REASON_STRING, message.getRawReasonString(), out);
}
if (omittedProperties <= 1) {
message.getUserProperties().encode(out);
}
}
private int reasonStringLength(final @NotNull M message) {
return nullablePropertyEncodedLength(message.getRawReasonString());
}
/**
* Base class of encoders for MQTT messages with an omissible Reason Code, an omissible Reason String and
* omissible User Properties. The Reason Code is omitted if it is the default and the property length is 0.
*/
static abstract class WithOmissibleCode< //
M extends MqttMessageWithUserProperties.WithReason.WithCode, R extends Mqtt5ReasonCode>
extends WithReason {
abstract int getFixedHeader();
abstract @NotNull R getDefaultReasonCode();
@Override
final int remainingLengthWithoutProperties(final @NotNull M message) {
return 1 + additionalRemainingLength(message); // reason code (1)
}
int additionalRemainingLength(final @NotNull M message) {
return 0;
}
@Override
final int propertyLength(final @NotNull M message) {
return omissiblePropertyLength(message) + additionalPropertyLength(message);
}
int additionalPropertyLength(final @NotNull M message) {
return 0;
}
@Override
protected void encode(
final @NotNull M message, final @NotNull ByteBuf out, final int remainingLength,
final int propertyLength, final int omittedProperties) {
encodeFixedHeader(out, remainingLength);
encodeVariableHeader(message, out, propertyLength, omittedProperties);
}
private void encodeFixedHeader(final @NotNull ByteBuf out, final int remainingLength) {
out.writeByte(getFixedHeader());
MqttVariableByteInteger.encode(remainingLength, out);
}
private void encodeVariableHeader(
final @NotNull M message, final @NotNull ByteBuf out, final int propertyLength,
final int omittedProperties) {
encodeAdditionalVariableHeader(message, out);
final R reasonCode = message.getReasonCode();
if (propertyLength == 0) {
if (reasonCode != getDefaultReasonCode()) {
out.writeByte(reasonCode.getCode());
}
} else {
out.writeByte(reasonCode.getCode());
MqttVariableByteInteger.encode(propertyLength, out);
encodeAdditionalProperties(message, out);
encodeOmissibleProperties(message, out, omittedProperties);
}
}
void encodeAdditionalVariableHeader(final @NotNull M message, final @NotNull ByteBuf out) {}
void encodeAdditionalProperties(final @NotNull M message, final @NotNull ByteBuf out) {}
@Override
final int propertyLengthWithHeader(final @NotNull M message, final int propertyLength) {
if (propertyLength == 0) {
return (message.getReasonCode() == getDefaultReasonCode()) ? -1 : 0;
}
return super.propertyLengthWithHeader(message, propertyLength);
}
/**
* Base class of encoders for MQTT messages with a Packet Identifier, an omissible Reason Code, an omissible
* Reason String and omissible User Properties. The Reason Code is omitted if it is the default and the
* property length is 0.
*/
static abstract class WithId< //
M extends MqttMessageWithUserProperties.WithReason.WithCode.WithId, R extends Mqtt5ReasonCode>
extends WithOmissibleCode {
@Override
int additionalRemainingLength(final @NotNull M message) {
return 2; // packet identifier (2)
}
@Override
void encodeAdditionalVariableHeader(final @NotNull M message, final @NotNull ByteBuf out) {
out.writeShort(message.getPacketIdentifier());
}
}
}
}
}