Attempt at unix pipe support

FFMpegCore.Test/FFProbeTests.cs

@@ -52,7 +52,6 @@ public void Probe_Success_FromStream_Async()
             using (var stream = File.OpenRead(VideoLibrary.LocalVideo.FullName))
             {
                 var info = output.ParseVideoInfoAsync(stream).WaitForResult();
-                
                 Assert.AreEqual(13, info.Duration.Seconds);
             }
         }

FFMpegCore/FFMPEG/Argument/Atoms/InputPipeArgument.cs

@@ -30,10 +30,8 @@ public override string GetStringValue()
 
         public override async Task ProcessDataAsync(CancellationToken token)
         {
-            await Pipe.WaitForConnectionAsync(token).ConfigureAwait(false);
-            if (!Pipe.IsConnected)
-                throw new TaskCanceledException();
-            await Writer.WriteDataAsync(Pipe).ConfigureAwait(false);
+            await Pipe.During(token).ConfigureAwait(false);
+            await Writer.WriteDataAsync(Pipe.GetStream()).ConfigureAwait(false);
         }
     }
 }

FFMpegCore/FFMPEG/Argument/Atoms/OutputPipeArgument.cs

@@ -24,10 +24,8 @@ public override string GetStringValue()
 
         public override async Task ProcessDataAsync(CancellationToken token)
         {
-            await Pipe.WaitForConnectionAsync(token).ConfigureAwait(false);
-            if (!Pipe.IsConnected)
-                throw new TaskCanceledException();
-            await Reader.ReadDataAsync(Pipe).ConfigureAwait(false);
+            await Pipe.During(token).ConfigureAwait(false);
+            await Reader.ReadDataAsync(Pipe.GetStream()).ConfigureAwait(false);
         }
     }
 }

FFMpegCore/FFMPEG/Argument/Atoms/PipeArgument.cs

@@ -2,38 +2,40 @@
 using System;
 using System.Collections.Generic;
 using System.IO.Pipes;
+using System.Runtime.InteropServices;
 using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
+using Mono.Unix;
 
 namespace FFMpegCore.FFMPEG.Argument
 {
     public abstract class PipeArgument : Argument
     {
-        public string PipeName { get; private set; }
-        public string PipePath => PipeHelpers.GetPipePath(PipeName);
+        public string PipePath => Pipe.PipePath;
 
-        protected NamedPipeServerStream Pipe { get; private set; }
+        protected INamedPipe Pipe { get; private set; }
         private PipeDirection direction;
 
         protected PipeArgument(PipeDirection direction)
         {
-            PipeName = PipeHelpers.GetUnqiuePipeName();
+            var pipeName = "FFMpegCore_Pipe_" + Guid.NewGuid();
+            Pipe = RuntimeInformation.IsOSPlatform(OSPlatform.Windows) switch
+            {
+                true => new WindowsNamedPipe(pipeName),
+                false => new UnixNamedPipe(pipeName)
+            };
             this.direction = direction;
         }
 
         public void OpenPipe()
         {
-            if (Pipe != null)
-                throw new InvalidOperationException("Pipe already has been opened");
-
-            Pipe = new NamedPipeServerStream(PipeName, direction, 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous);
+            Pipe.Open(direction);
         }
 
         public void ClosePipe()
         {
-            Pipe?.Dispose();
-            Pipe = null;
+            Pipe.Close();
         }
         public Task ProcessDataAsync()
         {

FFMpegCore/FFMPEG/Argument/Atoms/UnixNamedPipe.cs

@@ -0,0 +1,105 @@
+using System;
+using System.IO;
+using System.IO.Pipes;
+using System.Threading;
+using System.Threading.Tasks;
+using Instances;
+
+namespace FFMpegCore.FFMPEG.Argument
+{
+
+    public interface INamedPipe
+    {
+        public void Open(PipeDirection direction);
+        public Task During(CancellationToken cancellationToken);
+        public void Close();
+        System.IO.Stream GetStream();
+        string PipePath { get; }
+    }
+    
+    public class WindowsNamedPipe : INamedPipe
+    {
+        private readonly string _pipeName;
+
+        public WindowsNamedPipe(string pipeName)
+        {
+            _pipeName = pipeName;
+        }
+        public void Open(PipeDirection direction)
+        {
+            if (Pipe != null)
+                throw new InvalidOperationException("Pipe already has been opened");
+
+            Pipe = new NamedPipeServerStream(_pipeName, direction, 1, PipeTransmissionMode.Byte, PipeOptions.Asynchronous);
+        }
+
+        public async Task During(CancellationToken cancellationToken)
+        {
+            await Pipe.WaitForConnectionAsync(cancellationToken).ConfigureAwait(false);
+            if (!Pipe.IsConnected)
+                throw new TaskCanceledException();
+        }
+
+        public System.IO.Stream GetStream()
+        {
+            return Pipe;
+        }
+
+        public NamedPipeServerStream Pipe { get; set; }
+
+        public void Close()
+        {
+            Pipe?.Dispose();
+            Pipe = null;
+        }
+        public string PipePath => $@"\\.\pipe\{_pipeName}";
+    }
+    public class UnixNamedPipe : INamedPipe
+    {
+        private readonly string _pipeName;
+        private PipeDirection _direction;
+
+        public UnixNamedPipe(string pipeName)
+        {
+            _pipeName = pipeName;
+        }
+        
+        public void Open(PipeDirection direction)
+        {
+            if (direction == PipeDirection.InOut)
+                throw new NotImplementedException();
+            _direction = direction;
+            
+            if (File.Exists(PipePath))
+                throw new IOException($"Pipe name is already in use ({PipePath})");
+            
+            var (exitCode, _) = Instance.Finish("mkfifo", PipePath);
+            if (exitCode != 0)
+                throw new IOException($"Could not create FIFO file. (mkfifo failed with argument '{PipePath}')");
+        }
+        public Task During(CancellationToken cancellationToken)
+        {
+            return Task.CompletedTask;
+        }
+
+        public void Close()
+        {
+            if (!File.Exists(PipePath))
+                throw new IOException($"Could not find pipe to close");
+            
+            File.Delete(PipePath);
+        }
+
+        public System.IO.Stream GetStream()
+        {
+            return _direction switch
+            {
+                PipeDirection.In => File.OpenRead(PipePath),
+                PipeDirection.Out => File.OpenWrite(PipePath),
+                _ => throw new NotImplementedException()
+            };
+        }
+
+        public string PipePath => $"/tmp/CoreFxPipe_FIFO_{_pipeName}";
+    }
+}

FFMpegCore/FFMPEG/FFProbe.cs

@@ -121,7 +121,7 @@ public async Task<VideoInfo> ParseVideoInfoAsync(System.IO.Stream stream)
             var task = instance.FinishedRunning();
             try
             {
-                await pipeArgument.ProcessDataAsync();
+                await pipeArgument.ProcessDataAsync().ConfigureAwait(false);
                 pipeArgument.ClosePipe();
             }
             catch (IOException)

FFMpegCore/FFMPEG/Pipes/PipeHelpers.cs

@@ -1,18 +0,0 @@
-using System;
-using System.Runtime.InteropServices;
-
-namespace FFMpegCore.FFMPEG.Pipes
-{
-    static class PipeHelpers
-    {
-        public static string GetUnqiuePipeName() => "FFMpegCore_Pipe_" + Guid.NewGuid();
-
-        public static string GetPipePath(string pipeName)
-        {
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
-                return $@"\\.\pipe\{pipeName}";
-            else
-                return $"/tmp/CoreFxPipe_{pipeName}"; // dotnet uses unix sockets on unix, for more see https://github.com/dotnet/runtime/issues/24390
-        }
-    }
-}

FFMpegCore/FFMpegCore.csproj

@@ -32,6 +32,7 @@ Thanks to max619 and WeihanLi
 
   <ItemGroup>
     <PackageReference Include="Instances" Version="1.5.0" />
+    <PackageReference Include="Mono.Posix.NETStandard" Version="1.0.0" />
     <PackageReference Include="Newtonsoft.Json" Version="12.0.2" />
     <PackageReference Include="System.Drawing.Common" Version="4.5.1" />
   </ItemGroup>