Make HTTPClientResponse.init public

Sources/AsyncHTTPClient/AsyncAwait/AnyAsyncSequence.swift

@@ -0,0 +1,48 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the AsyncHTTPClient open source project
+//
+// Copyright (c) 2022 Apple Inc. and the AsyncHTTPClient project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of AsyncHTTPClient project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+@usableFromInline
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+struct AnyAsyncSequence<Element>: Sendable, AsyncSequence {
+    @usableFromInline typealias AsyncIteratorNextCallback = () async throws -> Element?
+
+    @usableFromInline struct AsyncIterator: AsyncIteratorProtocol {
+        @usableFromInline let nextCallback: AsyncIteratorNextCallback
+
+        @inlinable init(nextCallback: @escaping AsyncIteratorNextCallback) {
+            self.nextCallback = nextCallback
+        }
+
+        @inlinable mutating func next() async throws -> Element? {
+            try await self.nextCallback()
+        }
+    }
+
+    @usableFromInline var makeAsyncIteratorCallback: @Sendable () -> AsyncIteratorNextCallback
+
+    @inlinable init<SequenceOfBytes>(
+        _ asyncSequence: SequenceOfBytes
+    ) where SequenceOfBytes: AsyncSequence & Sendable, SequenceOfBytes.Element == Element {
+        self.makeAsyncIteratorCallback = {
+            var iterator = asyncSequence.makeAsyncIterator()
+            return {
+                try await iterator.next()
+            }
+        }
+    }
+
+    @inlinable func makeAsyncIterator() -> AsyncIterator {
+        .init(nextCallback: self.makeAsyncIteratorCallback())
+    }
+}

Sources/AsyncHTTPClient/AsyncAwait/AsyncLazySequence.swift

@@ -0,0 +1,52 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the AsyncHTTPClient open source project
+//
+// Copyright (c) 2022 Apple Inc. and the AsyncHTTPClient project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of AsyncHTTPClient project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+@usableFromInline
+struct AsyncLazySequence<Base: Sequence>: AsyncSequence {
+    @usableFromInline typealias Element = Base.Element
+    @usableFromInline struct AsyncIterator: AsyncIteratorProtocol {
+        @usableFromInline var iterator: Base.Iterator
+        @inlinable init(iterator: Base.Iterator) {
+            self.iterator = iterator
+        }
+
+        @inlinable mutating func next() async throws -> Base.Element? {
+            self.iterator.next()
+        }
+    }
+
+    @usableFromInline var base: Base
+
+    @inlinable init(base: Base) {
+        self.base = base
+    }
+
+    @inlinable func makeAsyncIterator() -> AsyncIterator {
+        .init(iterator: self.base.makeIterator())
+    }
+}
+
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension AsyncLazySequence: Sendable where Base: Sendable {}
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension AsyncLazySequence.AsyncIterator: Sendable where Base.Iterator: Sendable {}
+
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension Sequence {
+    /// Turns `self` into an `AsyncSequence` by vending each element of `self` asynchronously.
+    @inlinable var async: AsyncLazySequence<Self> {
+        .init(base: self)
+    }
+}

Sources/AsyncHTTPClient/AsyncAwait/HTTPClientResponse.swift

@@ -33,98 +33,125 @@ public struct HTTPClientResponse: Sendable {
     /// The body of this HTTP response.
     public var body: Body
 
-    /// A representation of the response body for an HTTP response.
-    ///
-    /// The body is streamed as an `AsyncSequence` of `ByteBuffer`, where each `ByteBuffer` contains
-    /// an arbitrarily large chunk of data. The boundaries between `ByteBuffer` objects in the sequence
-    /// are entirely synthetic and have no semantic meaning.
-    public struct Body: Sendable {
-        private let bag: Transaction
-        private let reference: ResponseRef
-
-        fileprivate init(_ transaction: Transaction) {
-            self.bag = transaction
-            self.reference = ResponseRef(transaction: transaction)
-        }
-    }
-
     init(
         bag: Transaction,
         version: HTTPVersion,
         status: HTTPResponseStatus,
         headers: HTTPHeaders
     ) {
-        self.body = Body(bag)
         self.version = version
         self.status = status
         self.headers = headers
+        self.body = Body(TransactionBody(bag))
+    }
+
+    @inlinable public init(
+        version: HTTPVersion = .http1_1,
+        status: HTTPResponseStatus = .ok,
+        headers: HTTPHeaders = [:],
+        body: Body = Body()
+    ) {
+        self.version = version
+        self.status = status
+        self.headers = headers
+        self.body = body
     }
 }
 
 @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
-extension HTTPClientResponse.Body: AsyncSequence {
-    public typealias Element = AsyncIterator.Element
+extension HTTPClientResponse {
+    /// A representation of the response body for an HTTP response.
+    ///
+    /// The body is streamed as an `AsyncSequence` of `ByteBuffer`, where each `ByteBuffer` contains
+    /// an arbitrarily large chunk of data. The boundaries between `ByteBuffer` objects in the sequence
+    /// are entirely synthetic and have no semantic meaning.
+    public struct Body: AsyncSequence, Sendable {
+        public typealias Element = ByteBuffer
+        public struct AsyncIterator: AsyncIteratorProtocol {
+            @usableFromInline var storage: Storage.AsyncIterator
 
-    public struct AsyncIterator: AsyncIteratorProtocol {
-        private let stream: IteratorStream
+            @inlinable init(storage: Storage.AsyncIterator) {
+                self.storage = storage
+            }
 
-        fileprivate init(stream: IteratorStream) {
-            self.stream = stream
+            @inlinable public mutating func next() async throws -> ByteBuffer? {
+                try await self.storage.next()
+            }
         }
 
-        public mutating func next() async throws -> ByteBuffer? {
-            try await self.stream.next()
+        @usableFromInline var storage: Storage
+
+        @inlinable public func makeAsyncIterator() -> AsyncIterator {
+            .init(storage: self.storage.makeAsyncIterator())
         }
     }
+}
 
-    public func makeAsyncIterator() -> AsyncIterator {
-        AsyncIterator(stream: IteratorStream(bag: self.bag))
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension HTTPClientResponse.Body {
+    @usableFromInline enum Storage: Sendable {
+        case transaction(TransactionBody)
+        case anyAsyncSequence(AnyAsyncSequence<ByteBuffer>)
     }
 }
 
 @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
-extension HTTPClientResponse.Body {
-    /// The purpose of this object is to inform the transaction about the response body being deinitialized.
-    /// If the users has not called `makeAsyncIterator` on the body, before it is deinited, the http
-    /// request needs to be cancelled.
-    fileprivate final class ResponseRef: Sendable {
-        private let transaction: Transaction
-
-        init(transaction: Transaction) {
-            self.transaction = transaction
+extension HTTPClientResponse.Body.Storage: AsyncSequence {
+    @usableFromInline typealias Element = ByteBuffer
+
+    @inlinable func makeAsyncIterator() -> AsyncIterator {
+        switch self {
+        case .transaction(let transaction):
+            return .transaction(transaction.makeAsyncIterator())
+        case .anyAsyncSequence(let anyAsyncSequence):
+            return .anyAsyncSequence(anyAsyncSequence.makeAsyncIterator())
         }
+    }
+}
+
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension HTTPClientResponse.Body.Storage {
+    @usableFromInline enum AsyncIterator {
+        case transaction(TransactionBody.AsyncIterator)
+        case anyAsyncSequence(AnyAsyncSequence<ByteBuffer>.AsyncIterator)
+    }
+}
 
-        deinit {
-            self.transaction.responseBodyDeinited()
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension HTTPClientResponse.Body.Storage.AsyncIterator: AsyncIteratorProtocol {
+    @inlinable mutating func next() async throws -> ByteBuffer? {
+        switch self {
+        case .transaction(let iterator):
+            return try await iterator.next()
+        case .anyAsyncSequence(var iterator):
+            defer { self = .anyAsyncSequence(iterator) }
+            return try await iterator.next()
         }
     }
 }
 
 @available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
 extension HTTPClientResponse.Body {
-    internal class IteratorStream {
-        struct ID: Hashable {
-            private let objectID: ObjectIdentifier
-
-            init(_ object: IteratorStream) {
-                self.objectID = ObjectIdentifier(object)
-            }
-        }
+    init(_ body: TransactionBody) {
+        self.init(.transaction(body))
+    }
 
-        private var id: ID { ID(self) }
-        private let bag: Transaction
+    @usableFromInline init(_ storage: Storage) {
+        self.storage = storage
+    }
 
-        init(bag: Transaction) {
-            self.bag = bag
-        }
+    public init() {
+        self = .stream(EmptyCollection<ByteBuffer>().async)
+    }
 
-        deinit {
-            self.bag.responseBodyIteratorDeinited(streamID: self.id)
-        }
+    @inlinable public static func stream<SequenceOfBytes>(
+        _ sequenceOfBytes: SequenceOfBytes
+    ) -> Self where SequenceOfBytes: AsyncSequence & Sendable, SequenceOfBytes.Element == ByteBuffer {
+        self.init(.anyAsyncSequence(AnyAsyncSequence(sequenceOfBytes.singleIteratorPrecondition)))
+    }
 
-        func next() async throws -> ByteBuffer? {
-            try await self.bag.nextResponsePart(streamID: self.id)
-        }
+    public static func bytes(_ byteBuffer: ByteBuffer) -> Self {
+        .stream(CollectionOfOne(byteBuffer).async)
     }
 }
 

Sources/AsyncHTTPClient/AsyncAwait/SingleIteratorPrecondition.swift

@@ -0,0 +1,45 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the AsyncHTTPClient open source project
+//
+// Copyright (c) 2022 Apple Inc. and the AsyncHTTPClient project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See CONTRIBUTORS.txt for the list of AsyncHTTPClient project authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Atomics
+
+/// Makes sure that a consumer of this `AsyncSequence` only calls `makeAsyncIterator()` at most once.
+/// If `makeAsyncIterator()` is called multiple times, the program crashes.
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+@usableFromInline struct SingleIteratorPrecondition<Base: AsyncSequence>: AsyncSequence {
+    @usableFromInline let base: Base
+    @usableFromInline let didCreateIterator: ManagedAtomic<Bool> = .init(false)
+    @usableFromInline typealias Element = Base.Element
+    @inlinable init(base: Base) {
+        self.base = base
+    }
+
+    @inlinable func makeAsyncIterator() -> Base.AsyncIterator {
+        precondition(
+            self.didCreateIterator.exchange(true, ordering: .relaxed) == false,
+            "makeAsyncIterator() is only allowed to be called at most once."
+        )
+        return self.base.makeAsyncIterator()
+    }
+}
+
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension SingleIteratorPrecondition: @unchecked Sendable where Base: Sendable {}
+
+@available(macOS 10.15, iOS 13.0, watchOS 6.0, tvOS 13.0, *)
+extension AsyncSequence {
+    @inlinable var singleIteratorPrecondition: SingleIteratorPrecondition<Self> {
+        .init(base: self)
+    }
+}

Sources/AsyncHTTPClient/AsyncAwait/Transaction+StateMachine.swift

@@ -30,7 +30,7 @@ extension Transaction {
             case queued(CheckedContinuation<HTTPClientResponse, Error>, HTTPRequestScheduler)
             case deadlineExceededWhileQueued(CheckedContinuation<HTTPClientResponse, Error>)
             case executing(ExecutionContext, RequestStreamState, ResponseStreamState)
-            case finished(error: Error?, HTTPClientResponse.Body.IteratorStream.ID?)
+            case finished(error: Error?, TransactionBody.AsyncIterator.ID?)
         }
 
         fileprivate enum RequestStreamState {
@@ -52,9 +52,9 @@ extension Transaction {
             // We are waiting for the user to create a response body iterator and to call next on
             // it for the first time.
             case waitingForResponseIterator(CircularBuffer<ByteBuffer>, next: Next)
-            case buffering(HTTPClientResponse.Body.IteratorStream.ID, CircularBuffer<ByteBuffer>, next: Next)
-            case waitingForRemote(HTTPClientResponse.Body.IteratorStream.ID, CheckedContinuation<ByteBuffer?, Error>)
-            case finished(HTTPClientResponse.Body.IteratorStream.ID, CheckedContinuation<ByteBuffer?, Error>)
+            case buffering(TransactionBody.AsyncIterator.ID, CircularBuffer<ByteBuffer>, next: Next)
+            case waitingForRemote(TransactionBody.AsyncIterator.ID, CheckedContinuation<ByteBuffer?, Error>)
+            case finished(TransactionBody.AsyncIterator.ID, CheckedContinuation<ByteBuffer?, Error>)
         }
 
         private var state: State
@@ -510,7 +510,7 @@ extension Transaction {
             }
         }
 
-        mutating func responseBodyIteratorDeinited(streamID: HTTPClientResponse.Body.IteratorStream.ID) -> FailAction {
+        mutating func responseBodyIteratorDeinited(streamID: TransactionBody.AsyncIterator.ID) -> FailAction {
             switch self.state {
             case .initialized, .queued, .deadlineExceededWhileQueued, .executing(_, _, .waitingForResponseHead):
                 preconditionFailure("Got notice about a deinited response body iterator, before we even received a response. Invalid state: \(self.state)")
@@ -536,7 +536,7 @@ extension Transaction {
         }
 
         mutating func consumeNextResponsePart(
-            streamID: HTTPClientResponse.Body.IteratorStream.ID,
+            streamID: TransactionBody.AsyncIterator.ID,
             continuation: CheckedContinuation<ByteBuffer?, Error>
         ) -> ConsumeAction {
             switch self.state {
@@ -639,8 +639,8 @@ extension Transaction {
         }
 
         private func verifyStreamIDIsEqual(
-            registered: HTTPClientResponse.Body.IteratorStream.ID,
-            this: HTTPClientResponse.Body.IteratorStream.ID,
+            registered: TransactionBody.AsyncIterator.ID,
+            this: TransactionBody.AsyncIterator.ID,
             file: StaticString = #file,
             line: UInt = #line
         ) {