add AsyncProcess, Concurreny for Foundation.Process

Package.swift

@@ -19,6 +19,11 @@ let package = Package(
     .package(url: "https://github.com/apple/swift-system", from: "1.2.1"),
     .package(url: "https://github.com/apple/swift-argument-parser", from: "1.2.2"),
     .package(url: "https://github.com/apple/swift-async-algorithms.git", from: "0.1.0"),
+    .package(url: "https://github.com/apple/swift-atomics.git", from: "1.0.0"),
+    .package(url: "https://github.com/apple/swift-nio.git", from: "2.56.0"),
+    .package(url: "https://github.com/apple/swift-nio-extras.git", from: "1.17.0"),
+    .package(url: "https://github.com/apple/swift-log.git", from: "1.5.2"),
+    .package(url: "https://github.com/apple/swift-collections.git", from: "1.0.0"),
   ],
   targets: [
     // Targets are the basic building blocks of a package. A target can define a module or a test suite.
@@ -45,5 +50,28 @@ let package = Package(
         .target(name: "SwiftSDKGenerator"),
       ]
     ),
+    .target(
+      name: "AsyncProcess",
+      dependencies: [
+        .product(name: "Atomics", package: "swift-atomics"),
+        .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
+        .product(name: "Logging", package: "swift-log"),
+        .product(name: "NIO", package: "swift-nio"),
+        .product(name: "NIOExtras", package: "swift-nio-extras"),
+        .product(name: "DequeModule", package: "swift-collections"),
+        .product(name: "SystemPackage", package: "swift-system"),
+      ]
+    ),
+    .testTarget(
+      name: "AsyncProcessTests",
+      dependencies: [
+        "AsyncProcess",
+        .product(name: "Atomics", package: "swift-atomics"),
+        .product(name: "AsyncAlgorithms", package: "swift-async-algorithms"),
+        .product(name: "NIO", package: "swift-nio"),
+        .product(name: "NIOConcurrencyHelpers", package: "swift-nio"),
+        .product(name: "Logging", package: "swift-log"),
+      ]
+    ),
   ]
 )

Sources/AsyncProcess/ChunkSequence.swift

@@ -0,0 +1,63 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+import NIO
+
+#if os(Linux) || os(Android) || os(Windows)
+@preconcurrency import Foundation
+#else
+import Foundation
+#endif
+
+public struct IllegalStreamConsumptionError: Error {
+  var description: String
+}
+
+public struct ChunkSequence: AsyncSequence & Sendable {
+  private let fileHandle: FileHandle?
+  private let group: EventLoopGroup
+
+  public init(takingOwnershipOfFileHandle fileHandle: FileHandle?, group: EventLoopGroup) {
+    self.group = group
+    self.fileHandle = fileHandle
+  }
+
+  public func makeAsyncIterator() -> AsyncIterator {
+    // This will close the file handle.
+    AsyncIterator(try! self.fileHandle?.fileContentStream(eventLoop: self.group.any()))
+  }
+
+  public typealias Element = ByteBuffer
+  public struct AsyncIterator: AsyncIteratorProtocol {
+    public typealias Element = ByteBuffer
+    internal typealias UnderlyingSequence = FileContentStream
+
+    private var underlyingIterator: UnderlyingSequence.AsyncIterator?
+
+    internal init(_ underlyingSequence: UnderlyingSequence?) {
+      self.underlyingIterator = underlyingSequence?.makeAsyncIterator()
+    }
+
+    public mutating func next() async throws -> Element? {
+      if self.underlyingIterator != nil {
+        return try await self.underlyingIterator!.next()
+      } else {
+        throw IllegalStreamConsumptionError(
+          description: """
+          Either `.discard`ed, `.inherit`ed or redirected this stream to a `.fileHandle`,
+          cannot also consume it. To consume, please `.stream` it.
+          """
+        )
+      }
+    }
+  }
+}

Sources/AsyncProcess/EOFSequence.swift

@@ -0,0 +1,27 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift open source project
+//
+// Copyright (c) 2022-2023 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See http://swift.org/LICENSE.txt for license information
+// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+public struct EOFSequence<Element>: AsyncSequence & Sendable {
+  public typealias Element = Element
+
+  public struct AsyncIterator: AsyncIteratorProtocol {
+    public mutating func next() async throws -> Element? {
+      nil
+    }
+  }
+
+  public init(of type: Element.Type = Element.self) {}
+
+  public func makeAsyncIterator() -> AsyncIterator {
+    AsyncIterator()
+  }
+}