modernuo/Projects/Server/Network/Pipe.cs

505 lines
14 KiB
C#

/*************************************************************************
* ModernUO *
* Copyright 2019-2020 - ModernUO Development Team *
* Email: hi@modernuo.com *
* File: Pipe.cs *
* *
* This program is free software: you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation, either version 3 of the License, or *
* (at your option) any later version. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program. If not, see <http://www.gnu.org/licenses/>. *
*************************************************************************/
using System;
using System.Runtime.CompilerServices;
using System.Threading;
namespace Server.Network
{
public interface IPipeTask<T> : INotifyCompletion
{
public IPipeTask<T> GetAwaiter();
public bool IsCompleted { get; }
public T GetResult();
}
public class Pipe<T>
{
public struct Result
{
public ArraySegment<T>[] Buffer { get; }
public bool IsClosed { get; set; }
public int Length
{
get
{
var length = 0;
for (int i = 0; i < Buffer.Length; i++)
{
length += Buffer[i].Count;
}
return length;
}
}
public void CopyFrom(ReadOnlySpan<T> bytes)
{
var remaining = bytes.Length;
var offset = 0;
if (remaining == 0)
{
return;
}
for (int i = 0; i < 2; i++)
{
var buffer = Buffer[i];
var sz = Math.Min(remaining, buffer.Count);
bytes.Slice(offset, sz).CopyTo(buffer);
remaining -= sz;
offset += sz;
if (remaining == 0)
{
return;
}
}
throw new OutOfMemoryException();
}
public Result(int segments)
{
IsClosed = false;
Buffer = new ArraySegment<T>[segments];
}
}
public class PipeWriter : IPipeTask<Result>
{
private readonly Pipe<T> _pipe;
private Result _result = new(2);
internal PipeWriter(Pipe<T> pipe) => _pipe = pipe;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint GetAvailable()
{
var read = _pipe._readIdx;
var write = _pipe._writeIdx;
if (read <= write)
{
if (read == 0)
{
return _pipe.Size - write - 1;
}
return _pipe.Size - write + (read - 1);
}
return read - write - 1;
}
public Result TryGetMemory()
{
var read = _pipe._readIdx;
var write = _pipe._writeIdx;
_result.IsClosed = _pipe._closed;
if (read <= write)
{
var readZero = read == 0;
var sz = _pipe.Size - write - (readZero ? 1 : 0);
_result.Buffer[0] = sz == 0 ? ArraySegment<T>.Empty : new ArraySegment<T>(_pipe._buffer, (int)write, (int)sz);
_result.Buffer[1] = readZero ? ArraySegment<T>.Empty : new ArraySegment<T>(_pipe._buffer, 0, (int)read - 1);
}
else
{
var sz = read - write - 1;
_result.Buffer[0] = sz == 0 ? ArraySegment<T>.Empty : new ArraySegment<T>(_pipe._buffer, (int)write, (int)sz);
_result.Buffer[1] = ArraySegment<T>.Empty;
}
return _result;
}
public IPipeTask<Result> GetMemory()
{
if (_pipe._writeAwaitBeginning)
{
throw new Exception("Double await on writer");
}
return this;
}
public void Advance(uint count)
{
var read = _pipe._readIdx;
var write = _pipe._writeIdx;
if (count == 0)
{
return;
}
if (count > _pipe.Size - 1)
{
throw new InvalidOperationException();
}
if (read <= write)
{
if (count > read + _pipe.Size - write - 1)
{
throw new InvalidOperationException();
}
var sz = Math.Min(count, _pipe.Size - write);
write += sz;
if (write > _pipe.Size - 1)
{
write = 0;
}
count -= sz;
if (count > 0)
{
if (count >= read)
{
throw new InvalidOperationException();
}
write = count;
}
}
else
{
if (count > read - write - 1)
{
throw new InvalidOperationException();
}
write += count;
}
// It's never valid to advance the write pointer to become equal to
// the read pointer. Check that here.
if (write == read)
{
throw new InvalidOperationException("Write index equals read index after advance");
}
_pipe._writeIdx = write;
}
public void Close()
{
_pipe._closed = true;
var waiting = _pipe._readAwaitBeginning;
if (!waiting)
{
return;
}
Action continuation;
do
{
continuation = _pipe._readContinuation;
} while (continuation == null);
_pipe._readContinuation = null;
_pipe._readAwaitBeginning = false;
ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), true);
}
public void Flush()
{
if (_pipe._readIdx == _pipe._writeIdx)
{
return;
}
var waiting = _pipe._readAwaitBeginning;
if (!waiting)
{
return;
}
Action continuation;
do
{
continuation = _pipe._readContinuation;
} while (continuation == null);
_pipe._readContinuation = null;
_pipe._readAwaitBeginning = false;
ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), true);
}
#region Awaitable
// The following makes it possible to await the writer. Do not use any of this directly.
public IPipeTask<Result> GetAwaiter() => this;
public bool IsCompleted
{
get
{
if (GetAvailable() > 0)
{
return true;
}
if (_pipe._closed)
{
return true;
}
_pipe._writeAwaitBeginning = true;
return false;
}
}
public Result GetResult() => TryGetMemory();
public void OnCompleted(Action continuation) => _pipe._writeContinuation = continuation;
#endregion
}
public class PipeReader : IPipeTask<Result>
{
private readonly Pipe<T> _pipe;
private Result _result = new(2);
internal PipeReader(Pipe<T> pipe) => _pipe = pipe;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public uint GetAvailable()
{
var read = _pipe._readIdx;
var write = _pipe._writeIdx;
if (read <= write)
{
return write - read;
}
return write + _pipe.Size - read;
}
public Result TryRead()
{
var read = _pipe._readIdx;
var write = _pipe._writeIdx;
_result.IsClosed = _pipe._closed;
if (read <= write)
{
_result.Buffer[0] = write - read == 0 ? ArraySegment<T>.Empty : new ArraySegment<T>(_pipe._buffer, (int)read, (int)(write - read));
_result.Buffer[1] = ArraySegment<T>.Empty;
}
else
{
_result.Buffer[0] = _pipe.Size - read == 0 ? ArraySegment<T>.Empty : new ArraySegment<T>(_pipe._buffer, (int)read, (int)(_pipe.Size - read));
_result.Buffer[1] = write == 0 ? ArraySegment<T>.Empty : new ArraySegment<T>(_pipe._buffer, 0, (int)write);
}
return _result;
}
public IPipeTask<Result> Read()
{
if (_pipe._readAwaitBeginning)
{
throw new Exception("Double await on reader");
}
return this;
}
public void Advance(uint count)
{
var read = _pipe._readIdx;
var write = _pipe._writeIdx;
if (read <= write)
{
if (count > write - read)
{
throw new InvalidOperationException();
}
read += count;
}
else
{
var sz = Math.Min(count, _pipe.Size - read);
read += sz;
if (read > _pipe.Size - 1)
{
read = 0;
}
count -= sz;
if (count > 0)
{
if (count > write)
{
throw new InvalidOperationException();
}
read = count;
}
}
_pipe._readIdx = read;
}
public void Commit()
{
if (_pipe._readIdx == ((_pipe._writeIdx + 1) & (_pipe.Size - 1)))
{
return;
}
var waiting = _pipe._writeAwaitBeginning;
if (!waiting)
{
return;
}
Action continuation;
do
{
continuation = _pipe._writeContinuation;
} while (continuation == null);
_pipe._writeContinuation = null;
_pipe._writeAwaitBeginning = false;
ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), true);
}
public void Close()
{
_pipe._closed = true;
var waiting = _pipe._writeAwaitBeginning;
if (!waiting)
{
return;
}
Action continuation;
do
{
continuation = _pipe._writeContinuation;
} while (continuation == null);
_pipe._writeContinuation = null;
_pipe._writeAwaitBeginning = false;
ThreadPool.UnsafeQueueUserWorkItem(_ => continuation(), true);
}
#region Awaitable
// The following makes it possible to await the reader. Do not use any of this directly.
public IPipeTask<Result> GetAwaiter() => this;
public bool IsCompleted
{
get
{
if (GetAvailable() > 0)
{
return true;
}
if (_pipe._closed)
{
return true;
}
_pipe._readAwaitBeginning = true;
return false;
}
}
public Result GetResult() => TryRead();
public void OnCompleted(Action continuation) => _pipe._readContinuation = continuation;
#endregion
}
private readonly T[] _buffer;
private volatile uint _writeIdx;
private volatile uint _readIdx;
private bool _closed;
public PipeWriter Writer { get; }
public PipeReader Reader { get; }
public uint Size => (uint)_buffer.Length;
public Pipe(T[] buf)
{
// Test if the buffer is a power of two
if (buf.Length == 0 || (buf.Length & (buf.Length - 1)) != 0)
{
throw new ArgumentOutOfRangeException(nameof(buf), "Pipe buffers must have a length that is a power of two");
}
_buffer = buf;
_writeIdx = 0;
_readIdx = 0;
_closed = false;
Writer = new PipeWriter(this);
Reader = new PipeReader(this);
}
#region Awaitable
private volatile bool _readAwaitBeginning;
private volatile Action _readContinuation;
private volatile bool _writeAwaitBeginning;
private volatile Action _writeContinuation;
#endregion
}
}