Make HBRequest/HBResponse Sendable (hummingbird-project#153)

* Made HBRequest Sendable

* Add UnsafeTransfer and use in HBRequest

* Make HBResponse Sendable

* Added _HBSendableProtocol

* format

* Make PerformanceTest an executableTarget

* Update FlatDictionary.swift

* Fix compile error

* Make MediaType Sendable

Sources/Hummingbird/AsyncAwaitSupport/Sendable.swift

@@ -0,0 +1,19 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Hummingbird server framework project
+//
+// Copyright (c) 2022 the Hummingbird authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+#if compiler(>=5.6)
+@preconcurrency public protocol _HBSendableProtocol: Sendable {}
+#else
+public protocol _HBSendableProtocol {}
+#endif

Sources/Hummingbird/AsyncAwaitSupport/UnsafeTransfer.swift

@@ -0,0 +1,66 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Hummingbird server framework project
+//
+// Copyright (c) 2022 the Hummingbird authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the SwiftNIO open source project
+//
+// Copyright (c) 2021-2022 Apple Inc. and the SwiftNIO project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+/// ``HBUnsafeTransfer`` can be used to make non-`Sendable` values `Sendable`.
+/// As the name implies, the usage of this is unsafe because it disables the sendable checking of the compiler.
+/// It can be used similar to `@unsafe Sendable` but for values instead of types.
+@usableFromInline
+struct HBUnsafeTransfer<Wrapped> {
+    @usableFromInline
+    var wrappedValue: Wrapped
+
+    @inlinable
+    init(_ wrappedValue: Wrapped) {
+        self.wrappedValue = wrappedValue
+    }
+}
+
+#if swift(>=5.5) && canImport(_Concurrency)
+extension HBUnsafeTransfer: @unchecked Sendable {}
+#endif
+
+extension HBUnsafeTransfer: Equatable where Wrapped: Equatable {}
+extension HBUnsafeTransfer: Hashable where Wrapped: Hashable {}
+
+/// ``HBUnsafeMutableTransferBox`` can be used to make non-`Sendable` values `Sendable` and mutable.
+/// It can be used to capture local mutable values in a `@Sendable` closure and mutate them from within the closure.
+/// As the name implies, the usage of this is unsafe because it disables the sendable checking of the compiler and does not add any synchronisation.
+@usableFromInline
+final class HBUnsafeMutableTransferBox<Wrapped> {
+    @usableFromInline
+    var wrappedValue: Wrapped
+
+    @inlinable
+    init(_ wrappedValue: Wrapped) {
+        self.wrappedValue = wrappedValue
+    }
+}
+
+#if swift(>=5.5) && canImport(_Concurrency)
+extension HBUnsafeMutableTransferBox: @unchecked Sendable {}
+#endif

Sources/Hummingbird/Extensions/Extensions.swift

@@ -12,6 +12,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+import HummingbirdCore
 import Logging
 
 /// Extend objects with additional member variables
@@ -91,3 +92,56 @@ public struct HBExtensions<ParentObject> {
 public protocol HBExtensible {
     var extensions: HBExtensions<Self> { get set }
 }
+
+/// Version of `HBExtensions` that requires all extensions are sendable
+public struct HBSendableExtensions<ParentObject> {
+    /// Initialize extensions
+    public init() {
+        self.items = [:]
+    }
+
+    /// Get optional extension from a `KeyPath`
+    public func get<Type: HBSendable>(_ key: KeyPath<ParentObject, Type>) -> Type? {
+        self.items[key]?.value as? Type
+    }
+
+    /// Get extension from a `KeyPath`
+    public func get<Type: HBSendable>(_ key: KeyPath<ParentObject, Type>, error: StaticString? = nil) -> Type {
+        guard let value = items[key]?.value as? Type else {
+            preconditionFailure(error?.description ?? "Cannot get extension of type \(Type.self) without having set it")
+        }
+        return value
+    }
+
+    /// Return if extension has been set
+    public func exists<Type: HBSendable>(_ key: KeyPath<ParentObject, Type>) -> Bool {
+        self.items[key]?.value != nil
+    }
+
+    /// Set extension for a `KeyPath`
+    /// - Parameters:
+    ///   - key: KeyPath
+    ///   - value: value to store in extension
+    ///   - shutdownCallback: closure to call when extensions are shutsdown
+    public mutating func set<Type: HBSendable>(_ key: KeyPath<ParentObject, Type>, value: Type) {
+        self.items[key] = .init(
+            value: value
+        )
+    }
+
+    struct Item {
+        let value: Any
+    }
+
+    var items: [PartialKeyPath<ParentObject>: Item]
+}
+
+/// Protocol for extensible classes
+public protocol HBSendableExtensible {
+    var extensions: HBSendableExtensions<Self> { get set }
+}
+
+#if compiler(>=5.6)
+/// Conform to @unchecked Sendable as the PartialKeyPath in the item dictionary is not Sendable
+extension HBSendableExtensions: @unchecked Sendable {}
+#endif

Sources/Hummingbird/HTTP/MediaType.swift

@@ -422,3 +422,8 @@ extension HBMediaType {
         "7z": .application7z,
     ]
 }
+
+#if swift(>=5.6)
+extension HBMediaType: Sendable {}
+extension HBMediaType.Category: Sendable {}
+#endif

Sources/Hummingbird/Router/Parameters.swift

@@ -114,3 +114,7 @@ extension HBParameters: CustomStringConvertible {
         String(describing: self.parameters)
     }
 }
+
+#if swift(>=5.6)
+extension HBParameters: Sendable {}
+#endif

Sources/Hummingbird/Server/Request.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2022 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -20,7 +20,7 @@ import NIOCore
 import NIOHTTP1
 
 /// Holds all the values required to process a request
-public struct HBRequest: HBExtensible {
+public struct HBRequest: HBSendableExtensible {
     // MARK: Member variables
 
     /// URI path
@@ -36,9 +36,9 @@ public struct HBRequest: HBExtensible {
     /// Logger to use
     public var logger: Logger
     /// reference to application
-    public var application: HBApplication { self._internal.application }
+    public var application: HBApplication { self._internal.application.wrappedValue }
     /// Request extensions
-    public var extensions: HBExtensions<HBRequest>
+    public var extensions: HBSendableExtensions<HBRequest>
     /// Request context (eventLoop, bytebuffer allocator and remote address)
     public var context: HBRequestContext { self._internal.context }
     /// EventLoop request is running on
@@ -61,8 +61,8 @@ public struct HBRequest: HBExtensible {
 
     /// endpoint that services this request.
     internal var endpointPath: String? {
-        get { self._internal.endpointPath }
-        set { self._internal.endpointPath = newValue }
+        get { self._internal.endpointPath.wrappedValue }
+        set { self._internal.endpointPath.wrappedValue = newValue }
     }
 
     // MARK: Initialization
@@ -90,7 +90,7 @@ public struct HBRequest: HBExtensible {
         )
         self.body = body
         self.logger = application.logger.with(metadataKey: "hb_id", value: .stringConvertible(Self.globalRequestID.loadThenWrappingIncrement(by: 1, ordering: .relaxed)))
-        self.extensions = HBExtensions()
+        self.extensions = .init()
     }
 
     // MARK: Methods
@@ -145,9 +145,9 @@ public struct HBRequest: HBExtensible {
             self.version = version
             self.method = method
             self.headers = headers
-            self.application = application
+            self.application = .init(application)
             self.context = context
-            self.endpointPath = endpointPath
+            self.endpointPath = .init(endpointPath)
         }
 
         /// URI path
@@ -158,13 +158,14 @@ public struct HBRequest: HBExtensible {
         let method: HTTPMethod
         /// Request HTTP headers
         let headers: HTTPHeaders
-        /// reference to application
-        let application: HBApplication
+        /// reference to application. Currently wrapped in HBUnsafeTransfer to make Sendable.
+        /// Hope to make it Sendable in the future
+        let application: HBUnsafeTransfer<HBApplication>
         /// request context
         let context: HBRequestContext
         /// Endpoint path. This is stored a var so it can be edited by the router. In theory this could
         /// be accessed on multiple thread/tasks at the same point but it is only ever edited by router
-        var endpointPath: String?
+        let endpointPath: HBUnsafeMutableTransferBox<String?>
     }
 
     private var _internal: _Internal
@@ -190,3 +191,8 @@ extension HBRequest: CustomStringConvertible {
         "uri: \(self.uri), version: \(self.version), method: \(self.method), headers: \(self.headers), body: \(self.body)"
     }
 }
+
+#if compiler(>=5.6)
+extension HBRequest: Sendable {}
+extension HBRequest._Internal: Sendable {}
+#endif

Sources/Hummingbird/Server/RequestContext.swift

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Hummingbird server framework project
 //
-// Copyright (c) 2021-2021 the Hummingbird authors
+// Copyright (c) 2021-2022 the Hummingbird authors
 // Licensed under Apache License v2.0
 //
 // See LICENSE.txt for license information
@@ -13,7 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 /// Context that created HBRequest.
-public protocol HBRequestContext {
+public protocol HBRequestContext: _HBSendableProtocol {
     /// EventLoop request is running on
     var eventLoop: EventLoop { get }
     /// ByteBuffer allocator used by request

Sources/Hummingbird/Server/Response.swift

@@ -16,15 +16,15 @@ import HummingbirdCore
 import NIOHTTP1
 
 /// Holds all the required to generate a HTTP Response
-public struct HBResponse: HBExtensible {
+public struct HBResponse: HBSendableExtensible {
     /// response status
     public var status: HTTPResponseStatus
     /// response headers
     public var headers: HTTPHeaders
     /// response body
     public var body: HBResponseBody
     /// Response extensions
-    public var extensions: HBExtensions<HBResponse>
+    public var extensions: HBSendableExtensions<HBResponse>
 
     /// Create an `HBResponse`
     ///
@@ -36,7 +36,7 @@ public struct HBResponse: HBExtensible {
         self.status = status
         self.headers = headers
         self.body = body
-        self.extensions = HBExtensions()
+        self.extensions = .init()
     }
 }
 
@@ -45,3 +45,7 @@ extension HBResponse: CustomStringConvertible {
         "status: \(self.status), headers: \(self.headers), body: \(self.body)"
     }
 }
+
+#if compiler(>=5.6)
+extension HBResponse: Sendable {}
+#endif

Sources/Hummingbird/Utils/FlatDictionary.swift

@@ -117,3 +117,8 @@ public struct FlatDictionary<Key: Hashable, Value>: Collection {
     private var elements: [Element]
     private var hashKeys: [Int]
 }
+
+#if compiler(>=5.6)
+// FlatDictionary is Sendable when Key and Value are Sendable
+extension FlatDictionary: Sendable where Key: Sendable, Value: Sendable {}
+#endif