WIP: shutdown

Author: milseman

Sources/System/Internals/Constants.swift

@@ -514,3 +514,13 @@ internal var _MSG_PEEK: CInt { MSG_PEEK }
 
 @_alwaysEmitIntoClient
 internal var _MSG_WAITALL: CInt { MSG_WAITALL }
+
+@_alwaysEmitIntoClient
+internal var _SHUT_RD: CInt { SHUT_RD }
+
+@_alwaysEmitIntoClient
+internal var _SHUT_WR: CInt { SHUT_WR }
+
+@_alwaysEmitIntoClient
+internal var _SHUT_RDWR: CInt { SHUT_RDWR }
+

Sources/System/Internals/Syscalls.swift

@@ -122,3 +122,10 @@ internal func system_socket(_ domain: CInt, type: CInt, protocol: CInt) -> CInt
   #endif
   return socket(domain, type, `protocol`)
 }
+
+internal func system_shutdown(_ socket: CInt, _ how: CInt) -> CInt {
+  #if ENABLE_MOCKING
+  if mockingEnabled { return _mock(socket, how) }
+  #endif
+  return shutdown(socket, how)
+}

Sources/System/Sockets/SocketDescriptor.swift

@@ -184,6 +184,29 @@ extension SocketDescriptor {
     // TODO: MSG_NOSIGNAL
   }
 
+  public struct ShutdownKind: RawRepresentable, Hashable, Codable {
+    @_alwaysEmitIntoClient
+    public var rawValue: CInt
+
+    @_alwaysEmitIntoClient
+    public init(rawValue: CInt) { self.rawValue = rawValue }
+
+    /// Further receives will be disallowed
+    ///
+    /// The corresponding C constant is `SHUT_RD`
+    public static var read: ShutdownKind { ShutdownKind(rawValue: _SHUT_RD) }
+
+    /// Further sends will be disallowed
+    ///
+    /// The corresponding C constant is `SHUT_RD`
+    public static var write: ShutdownKind { ShutdownKind(rawValue: _SHUT_WR) }
+
+    /// Further sends and receives will be disallowed
+    ///
+    /// The corresponding C constant is `SHUT_RDWR`
+    public static var readWrite: ShutdownKind { ShutdownKind(rawValue: _SHUT_RDWR) }
+  }
+
 }
 
 extension SocketDescriptor {

Sources/System/Sockets/SocketOperations.swift

@@ -48,5 +48,23 @@ extension SocketDescriptor {
     }.map(SocketDescriptor.init(rawValue:))
   }
 
+  /// Deletes a socket's file descriptor.
+  ///
+  /// This is equivalent to `socket.fileDescriptor.close()`
+  @_alwaysEmitIntoClient
+  public func close() throws { try fileDescriptor.close() }
+
+  /// Shutdown part of a full-duplex connection
+  ///
+  /// The corresponding C function is `shutdown`
+  @_alwaysEmitIntoClient
+  public func shutdown(_ how: ShutdownKind) throws {
+    try _shutdown(how).get()
+  }
+
+  @usableFromInline
+  internal func _shutdown(_ how: ShutdownKind) -> Result<(), Errno> {
+    nothingOrErrno(system_shutdown(self.rawValue, how.rawValue))
+  }
 
 }

Tests/SystemTests/SocketTest.swift

@@ -20,11 +20,18 @@ final class SocketTest: XCTestCase {
 
   func testSyscalls() {
 
+    let socket = SocketDescriptor(rawValue: 3)
+    let rawSocket = socket.rawValue
+
     let syscallTestCases: Array<MockTestCase> = [
       MockTestCase(name: "socket", PF_INET6, SOCK_STREAM, 0, interruptable: true) {
         retryOnInterrupt in
         _ = try SocketDescriptor.open(.ipv6, .stream, retryOnInterrupt: retryOnInterrupt)
       },
+      MockTestCase(name: "shutdown", rawSocket, SHUT_RD, interruptable: false) {
+        retryOnInterrupt in
+        _ = try socket.shutdown(.read)
+      },
     ]
 
     syscallTestCases.forEach { $0.runAllTests() }