refactor old APM [Begin/End]Accept methods on top of Task APIs, and e…

…nable for Unix as well (#51212)

* refactor old APM [Begin/End]Accept methods on top of Task APIs, and enable for Unix as well

* fix BeginAccept to throw synchronously, and relevant test changes

* fix AcceptReceive test to run on unix too

* dispose accepted socket if receive throws

* remove CallbackClosure cache

* fix test helper to indicate AcceptReceive with EAP is still only supported on Windows

Co-authored-by: Geoffrey Kizer <geoffrek@windows.microsoft.com>

src/libraries/System.Net.Sockets/src/System.Net.Sockets.csproj

@@ -43,7 +43,6 @@
     <Compile Include="System\Net\Sockets\TransmitFileOptions.cs" />
     <Compile Include="System\Net\Sockets\UDPClient.cs" />
     <Compile Include="System\Net\Sockets\UdpReceiveResult.cs" />
-    <Compile Include="System\Net\Sockets\AcceptOverlappedAsyncResult.cs" />
     <Compile Include="System\Net\Sockets\BaseOverlappedAsyncResult.cs" />
     <Compile Include="System\Net\Sockets\UnixDomainSocketEndPoint.cs" />
     <!-- Logging -->
@@ -89,7 +88,6 @@
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsWindows)' == 'true'">
     <!-- Windows: CoreCLR -->
-    <Compile Include="System\Net\Sockets\AcceptOverlappedAsyncResult.Windows.cs" />
     <Compile Include="System\Net\Sockets\BaseOverlappedAsyncResult.Windows.cs" />
     <Compile Include="System\Net\Sockets\DynamicWinsockMethods.cs" />
     <Compile Include="System\Net\Sockets\SafeSocketHandle.Windows.cs" />
@@ -184,7 +182,6 @@
              Link="Common\System\Net\CompletionPortHelper.Windows.cs" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetsUnix)' == 'true'">
-    <Compile Include="System\Net\Sockets\AcceptOverlappedAsyncResult.Unix.cs" />
     <Compile Include="System\Net\Sockets\BaseOverlappedAsyncResult.Unix.cs" />
     <Compile Include="System\Net\Sockets\SafeSocketHandle.Unix.cs" />
     <Compile Include="System\Net\Sockets\Socket.Unix.cs" />

src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.Unix.cs

@@ -27,26 +27,6 @@ public SocketInformation DuplicateAndClose(int targetProcessId)
             throw new PlatformNotSupportedException(SR.net_sockets_duplicateandclose_notsupported);
         }
 
-        public IAsyncResult BeginAccept(int receiveSize, AsyncCallback? callback, object? state)
-        {
-            throw new PlatformNotSupportedException(SR.net_sockets_accept_receive_apm_notsupported);
-        }
-
-        public IAsyncResult BeginAccept(Socket? acceptSocket, int receiveSize, AsyncCallback? callback, object? state)
-        {
-            throw new PlatformNotSupportedException(SR.net_sockets_accept_receive_apm_notsupported);
-        }
-
-        public Socket EndAccept(out byte[] buffer, IAsyncResult asyncResult)
-        {
-            throw new PlatformNotSupportedException(SR.net_sockets_accept_receive_apm_notsupported);
-        }
-
-        public Socket EndAccept(out byte[] buffer, out int bytesTransferred, IAsyncResult asyncResult)
-        {
-            throw new PlatformNotSupportedException(SR.net_sockets_accept_receive_apm_notsupported);
-        }
-
         internal bool PreferInlineCompletions
         {
             get => _handle.PreferInlineCompletions;

src/libraries/System.Net.Sockets/src/System/Net/Sockets/Socket.Windows.cs

@@ -7,6 +7,7 @@
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Threading;
+using System.Threading.Tasks;
 using System.Runtime.Versioning;
 
 namespace System.Net.Sockets
@@ -145,30 +146,6 @@ public SocketInformation DuplicateAndClose(int targetProcessId)
             return info;
         }
 
-        public IAsyncResult BeginAccept(int receiveSize, AsyncCallback? callback, object? state)
-        {
-            return BeginAccept(acceptSocket: null, receiveSize, callback, state);
-        }
-
-        // This is the truly async version that uses AcceptEx.
-        public IAsyncResult BeginAccept(Socket? acceptSocket, int receiveSize, AsyncCallback? callback, object? state)
-        {
-            return BeginAcceptCommon(acceptSocket, receiveSize, callback, state);
-        }
-
-        public Socket EndAccept(out byte[] buffer, IAsyncResult asyncResult)
-        {
-            Socket socket = EndAccept(out byte[] innerBuffer, out int bytesTransferred, asyncResult);
-            buffer = new byte[bytesTransferred];
-            Buffer.BlockCopy(innerBuffer, 0, buffer, 0, bytesTransferred);
-            return socket;
-        }
-
-        public Socket EndAccept(out byte[] buffer, out int bytesTransferred, IAsyncResult asyncResult)
-        {
-            return EndAcceptCommon(out buffer!, out bytesTransferred, asyncResult);
-        }
-
         private DynamicWinsockMethods GetDynamicWinsockMethods()
         {
             return _dynamicWinsockMethods ??= DynamicWinsockMethods.GetMethods(_addressFamily, _socketType, _protocolType);
@@ -439,7 +416,7 @@ private IAsyncResult BeginSendFileInternal(string? fileName, byte[]? preBuffer,
                 throw new SocketException((int)errorCode);
             }
 
-            asyncResult.FinishPostingAsyncOp(ref Caches.SendClosureCache);
+            asyncResult.FinishPostingAsyncOp();
 
             return asyncResult;
         }