private static async Task <bool> GetHeader(Stream stream, byte[] messageHeader, ISharedArrayPool sharedArrayPool)
{
var binaryReader = new AsyncBinaryReader(stream);
var messageHeaderLength = await binaryReader.ReadUInt16Async();
Debug.Assert(messageHeaderLength == messageHeader.Length);
if (messageHeaderLength != messageHeader.Length)
{
// 消息不对，忽略
return(false);
}
var messageHeaderBuffer = sharedArrayPool.Rent(messageHeader.Length);
try
{
var readCount = await ReadBufferAsync(stream, messageHeaderBuffer, messageHeader.Length);
Debug.Assert(readCount == messageHeader.Length);
if (ByteListExtension.Equals(messageHeaderBuffer, messageHeader, readCount))
{
// 读对了
return(true);
}
else
{
// 发过来的消息是出错的
return(false);
}
}
finally
{
sharedArrayPool.Return(messageHeaderBuffer);
}
}
public ByteListMessageStream(byte[] buffer, int count, ISharedArrayPool sharedArrayPool) : base(buffer, 0,
count, false)
{
_sharedArrayPool = sharedArrayPool;
Buffer = buffer;
}
public static async Task <IpcMessageResult> ReadAsync(Stream stream,
byte[] messageHeader, ISharedArrayPool sharedArrayPool)
{
/*
* UInt16 Message Header Length 消息头的长度
* byte[] Message Header 消息头的内容
* UInt32 Version 当前IPC服务的版本
* UInt64 Ack 用于给对方确认收到消息使用
* UInt32 Empty 给以后版本使用的值
* UInt16 Command Type 命令类型，业务端的值将会是 0 而框架层采用其他值
* UInt32 Content Length 这条消息的内容长度
* byte[] Content 实际的内容
*/
if (!await GetHeader(stream, messageHeader, sharedArrayPool))
{
// 消息不对，忽略
return(new IpcMessageResult("Message Header no match"));
}
var binaryReader = new AsyncBinaryReader(stream);
// UInt32 Version 当前IPC服务的版本
var version = await binaryReader.ReadUInt32Async();
Debug.Assert(version == 1);
if (version == 0)
{
// 这是上个版本的，但是不兼容了
return(new IpcMessageResult("收到版本为 0 的旧版本消息，但是不兼容此版本"));
}
// UInt64 Ack 用于给对方确认收到消息使用
var ack = await binaryReader.ReadReadUInt64Async();
// UInt32 Empty 给以后版本使用的值
var empty = await binaryReader.ReadUInt32Async();
Debug.Assert(empty == 0);
// UInt16 Command Type 命令类型，业务端的值将会是大于 0 而框架层采用其他值
var commandType = (IpcMessageCommandType)await binaryReader.ReadUInt16Async();
// UInt32 Content Length 这条消息的内容长度
var messageLength = await binaryReader.ReadUInt32Async();
if (messageLength > IpcConfiguration.MaxMessageLength)
{
// 太长了
return(new IpcMessageResult(
$"Message Length too long MessageLength={messageLength} MaxMessageLength={IpcConfiguration.MaxMessageLength}. {DebugContext.OverMaxMessageLength}"));
}
var messageBuffer = sharedArrayPool.Rent((int)messageLength);
// byte[] Content 实际的内容
var readCount = await ReadBufferAsync(stream, messageBuffer, (int)messageLength);
Debug.Assert(readCount == messageLength);
var ipcMessageContext = new IpcMessageContext(ack, messageBuffer, messageLength, sharedArrayPool);
return(new IpcMessageResult(success: true, ipcMessageContext, commandType));
}
public static async Task <(bool success, IpcMessageContext ipcMessageContext)> ReadAsync(Stream stream,
byte[] messageHeader, ISharedArrayPool sharedArrayPool,
int maxMessageLength = ushort.MaxValue *byte.MaxValue)
{
try
{
/*
* UInt16 Message Header Length
* byte[] Message Header
* UInt32 Version
* UInt64 Ack
* UInt32 Empty
* UInt32 Content Length
* byte[] Content
*/
if (!await GetHeader(stream, messageHeader, sharedArrayPool))
{
// 消息不对，忽略
return((false, default) !);