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- make MqttPacketReader and Writer a specialized version of their Binary counterparts

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- improved message framing. as basis to improve buffering
- share more common code for the writer part
This commit is contained in:
JanEggers
2017-09-10 15:41:39 +02:00
parent a4d393ae28
commit 644bcfba27
4 changed files with 323 additions and 393 deletions
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MQTTnet.Core/Serializer/MqttPacketReader.cs
+53 -86
View File
@@ -2,55 +2,28 @@
using System.IO;
using System.Text;
using System.Threading.Tasks;
using MQTTnet.Core.Channel;
using MQTTnet.Core.Exceptions;
using MQTTnet.Core.Protocol;
using MQTTnet.Core.Channel;
using MQTTnet.Core.Packets;
namespace MQTTnet.Core.Serializer
{
public sealed class MqttPacketReader : IDisposable
public sealed class MqttPacketReader : BinaryReader
{
private readonly MemoryStream _remainingData = new MemoryStream(1024);
private readonly IMqttCommunicationChannel _source;
private readonly MqttPacketHeader _header;
private int _remainingLength;
public MqttPacketReader(IMqttCommunicationChannel source)
public MqttPacketReader(Stream stream, MqttPacketHeader header)
: base(stream)
{
_source = source ?? throw new ArgumentNullException(nameof(source));
_header = header;
}
public MqttControlPacketType ControlPacketType { get; private set; }
public byte FixedHeader { get; private set; }
public bool EndOfRemainingData => _remainingData.Position == _remainingData.Length;
public async Task ReadToEndAsync()
public bool EndOfRemainingData => BaseStream.Position == _header.BodyLength;
public override ushort ReadUInt16()
{
await ReadFixedHeaderAsync().ConfigureAwait(false);
await ReadRemainingLengthAsync().ConfigureAwait(false);
if (_remainingLength == 0)
{
return;
}
var buffer = new byte[_remainingLength];
await ReadFromSourceAsync(buffer).ConfigureAwait(false);
_remainingData.Write(buffer, 0, buffer.Length);
_remainingData.Position = 0;
}
public byte ReadRemainingDataByte()
{
return ReadRemainingData(1)[0];
}
public ushort ReadRemainingDataUShort()
{
var buffer = ReadRemainingData(2);
var buffer = ReadBytes(2);
var temp = buffer[0];
buffer[0] = buffer[1];
@@ -59,31 +32,59 @@ namespace MQTTnet.Core.Serializer
return BitConverter.ToUInt16(buffer, 0);
}
public string ReadRemainingDataStringWithLengthPrefix()
public string ReadStringWithLengthPrefix()
{
var buffer = ReadRemainingDataWithLengthPrefix();
var buffer = ReadWithLengthPrefix();
return Encoding.UTF8.GetString(buffer, 0, buffer.Length);
}
public byte[] ReadRemainingDataWithLengthPrefix()
public byte[] ReadWithLengthPrefix()
{
var length = ReadRemainingDataUShort();
return ReadRemainingData(length);
var length = ReadUInt16();
return ReadBytes(length);
}
public byte[] ReadRemainingData()
{
return ReadRemainingData(_remainingLength - (int)_remainingData.Position);
return ReadBytes(_header.BodyLength - (int)BaseStream.Position);
}
public byte[] ReadRemainingData(int length)
public static async Task<MqttPacketHeader> ReadHeaderFromSourceAsync(IMqttCommunicationChannel source)
{
var buffer = new byte[length];
_remainingData.Read(buffer, 0, buffer.Length);
return buffer;
var fixedHeader = await ReadStreamByteAsync(source).ConfigureAwait(false);
var byteReader = new ByteReader(fixedHeader);
byteReader.Read(4);
var controlPacketType = (MqttControlPacketType)byteReader.Read(4);
var bodyLength = await ReadBodyLengthFromSourceAsync(source).ConfigureAwait(false);
return new MqttPacketHeader()
{
FixedHeader = fixedHeader,
ControlPacketType = controlPacketType,
BodyLength = bodyLength
};
}
private async Task ReadRemainingLengthAsync()
private static async Task<byte> ReadStreamByteAsync(IMqttCommunicationChannel source)
{
var buffer = new byte[1];
await ReadFromSourceAsync(source, buffer).ConfigureAwait(false);
return buffer[0];
}
public static async Task ReadFromSourceAsync(IMqttCommunicationChannel source, byte[] buffer)
{
try
{
await source.ReadAsync(buffer);
}
catch (Exception exception)
{
throw new MqttCommunicationException(exception);
}
}
private static async Task<int> ReadBodyLengthFromSourceAsync(IMqttCommunicationChannel source)
{
// Alorithm taken from http://docs.oasis-open.org/mqtt/mqtt/v3.1.1/os/mqtt-v3.1.1-os.html.
var multiplier = 1;
@@ -91,7 +92,7 @@ namespace MQTTnet.Core.Serializer
byte encodedByte;
do
{
encodedByte = await ReadStreamByteAsync().ConfigureAwait(false);
encodedByte = await ReadStreamByteAsync(source).ConfigureAwait(false);
value += (encodedByte & 127) * multiplier;
multiplier *= 128;
if (multiplier > 128 * 128 * 128)
@@ -99,41 +100,7 @@ namespace MQTTnet.Core.Serializer
throw new MqttProtocolViolationException("Remaining length is ivalid.");
}
} while ((encodedByte & 128) != 0);
_remainingLength = value;
}
private Task ReadFromSourceAsync(byte[] buffer)
{
try
{
return _source.ReadAsync(buffer);
}
catch (Exception exception)
{
throw new MqttCommunicationException(exception);
}
}
private async Task<byte> ReadStreamByteAsync()
{
var buffer = new byte[1];
await ReadFromSourceAsync(buffer).ConfigureAwait(false);
return buffer[0];
}
private async Task ReadFixedHeaderAsync()
{
FixedHeader = await ReadStreamByteAsync().ConfigureAwait(false);
var byteReader = new ByteReader(FixedHeader);
byteReader.Read(4);
ControlPacketType = (MqttControlPacketType)byteReader.Read(4);
}
public void Dispose()
{
_remainingData?.Dispose();
return value;
}
}
}