WIP: add FileDescriptor forwarding methods

Author: milseman

Sources/System/Sockets/SocketHelpers.swift

@@ -0,0 +1,42 @@
+/*
+ This source file is part of the Swift System open source project
+
+ Copyright (c) 2021 Apple Inc. and the Swift System project authors
+ Licensed under Apache License v2.0 with Runtime Library Exception
+
+ See https://swift.org/LICENSE.txt for license information
+*/
+
+extension SocketDescriptor {
+  /// Writes a sequence of bytes to the socket
+  ///
+  /// This is equivalent to calling `fileDescriptor.writeAll(_:)`
+  ///
+  /// - Parameter sequence: The bytes to write.
+  /// - Returns: The number of bytes written, equal to the number of elements in `sequence`.
+  @_alwaysEmitIntoClient
+  @discardableResult
+  public func writeAll<S: Sequence>(
+    _ sequence: S
+  ) throws -> Int where S.Element == UInt8 {
+    try fileDescriptor.writeAll(sequence)
+  }
+
+  /// Runs a closure and then closes the socket, even if an error occurs.
+  ///
+  /// This is equivalent to calling `fileDescriptor.closeAfter(_:)`
+  ///
+  /// - Parameter body: The closure to run.
+  ///   If the closure throws an error,
+  ///   this method closes the socket before it rethrows that error.
+  ///
+  /// - Returns: The value returned by the closure.
+  ///
+  /// If `body` throws an error
+  /// or an error occurs while closing the socket,
+  /// this method rethrows that error.
+  public func closeAfter<R>(_ body: () throws -> R) throws -> R {
+    try fileDescriptor.closeAfter(body)
+  }
+}
+

Sources/System/Sockets/SocketOperations.swift

@@ -48,12 +48,6 @@ 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`
@@ -87,3 +81,57 @@ extension SocketDescriptor {
 
 
 }
+
+// MARK: - Forward FileDescriptor methods
+extension SocketDescriptor {
+  /// Deletes a socket's file descriptor.
+  ///
+  /// This is equivalent to calling `fileDescriptor.close()`
+  @_alwaysEmitIntoClient
+  public func close() throws { try fileDescriptor.close() }
+
+  /// Reads bytes from a socket.
+  ///
+  /// This is equivalent to calling `fileDescriptor.read(into:retryOnInterrupt:)`
+  ///
+  /// - Parameters:
+  ///   - buffer: The region of memory to read into.
+  ///   - retryOnInterrupt: Whether to retry the read operation
+  ///     if it throws ``Errno/interrupted``.
+  ///     The default is `true`.
+  ///     Pass `false` to try only once and throw an error upon interruption.
+  /// - Returns: The number of bytes that were read.
+  ///
+  /// The corresponding C function is `read`.
+  @_alwaysEmitIntoClient
+  public func read(
+    into buffer: UnsafeMutableRawBufferPointer, retryOnInterrupt: Bool = true
+  ) throws -> Int {
+    try fileDescriptor.read(into: buffer, retryOnInterrupt: retryOnInterrupt)
+  }
+
+  /// Writes the contents of a buffer to the socket.
+  ///
+  /// This is equivalent to `fileDescriptor.write(_:retryOnInterrupt:)`
+  ///
+  /// - Parameters:
+  ///   - buffer: The region of memory that contains the data being written.
+  ///   - retryOnInterrupt: Whether to retry the write operation
+  ///     if it throws ``Errno/interrupted``.
+  ///     The default is `true`.
+  ///     Pass `false` to try only once and throw an error upon interruption.
+  /// - Returns: The number of bytes that were written.
+  ///
+  /// After writing,
+  /// this method increments the file's offset by the number of bytes written.
+  /// To change the file's offset,
+  /// call the ``seek(offset:from:)`` method.
+  ///
+  /// The corresponding C function is `write`.
+  @_alwaysEmitIntoClient
+  public func write(
+    _ buffer: UnsafeRawBufferPointer, retryOnInterrupt: Bool = true
+  ) throws -> Int {
+    try fileDescriptor.write(buffer, retryOnInterrupt: retryOnInterrupt)
+  }
+}