[SE-0304] Align Task API implementation with the fourth revision of the proposal

stdlib/public/Concurrency/CMakeLists.txt

@@ -70,6 +70,7 @@ add_swift_target_library(swift_Concurrency ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} I
   TaskGroup.swift
   TaskLocal.cpp
   TaskLocal.swift
+  TaskSleep.swift
   ThreadSanitizer.cpp
   Mutex.cpp
   AsyncStreamBuffer.swift

stdlib/public/Concurrency/PartialAsyncTask.swift

@@ -18,8 +18,6 @@ import Swift
 @frozen
 public struct UnownedJob {
   private var context: Builtin.Job
-
-  public func run() { }
 }
 
 @available(SwiftStdlib 5.5, *)

stdlib/public/Concurrency/SourceCompatibilityShims.swift

@@ -190,65 +190,101 @@ extension Task where Failure == Never {
 
 @available(SwiftStdlib 5.5, *)
 extension TaskGroup {
-  @available(*, deprecated, renamed: "async(priority:operation:)")
+  @available(*, deprecated, renamed: "addTask(priority:operation:)")
   @_alwaysEmitIntoClient
   public mutating func add(
       priority: TaskPriority? = nil,
       operation: __owned @Sendable @escaping () async -> ChildTaskResult
   ) async -> Bool {
-    return self.asyncUnlessCancelled(priority: priority) {
+    return self.addTaskUnlessCancelled(priority: priority) {
       await operation()
     }
   }
 
-  @available(*, deprecated, renamed: "async(priority:operation:)")
+  @available(*, deprecated, renamed: "addTask(priority:operation:)")
   @_alwaysEmitIntoClient
   public mutating func spawn(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async -> ChildTaskResult
   ) {
-    async(priority: priority, operation: operation)
+    addTask(priority: priority, operation: operation)
   }
 
-  @available(*, deprecated, renamed: "asyncUnlessCancelled(priority:operation:)")
+  @available(*, deprecated, renamed: "addTaskUnlessCancelled(priority:operation:)")
   @_alwaysEmitIntoClient
   public mutating func spawnUnlessCancelled(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async -> ChildTaskResult
   ) -> Bool {
-    asyncUnlessCancelled(priority: priority, operation: operation)
+    addTaskUnlessCancelled(priority: priority, operation: operation)
+  }
+
+  @available(*, deprecated, renamed: "addTask(priority:operation:)")
+  @_alwaysEmitIntoClient
+  public mutating func async(
+    priority: TaskPriority? = nil,
+    operation: __owned @Sendable @escaping () async -> ChildTaskResult
+  ) {
+    addTask(priority: priority, operation: operation)
+  }
+
+  @available(*, deprecated, renamed: "addTaskUnlessCancelled(priority:operation:)")
+  @_alwaysEmitIntoClient
+  public mutating func asyncUnlessCancelled(
+    priority: TaskPriority? = nil,
+    operation: __owned @Sendable @escaping () async -> ChildTaskResult
+  ) -> Bool {
+    addTaskUnlessCancelled(priority: priority, operation: operation)
   }
 }
 
 @available(SwiftStdlib 5.5, *)
 extension ThrowingTaskGroup {
-  @available(*, deprecated, renamed: "async(priority:operation:)")
+  @available(*, deprecated, renamed: "addTask(priority:operation:)")
   @_alwaysEmitIntoClient
   public mutating func add(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
   ) async -> Bool {
-    return self.asyncUnlessCancelled(priority: priority) {
+    return self.addTaskUnlessCancelled(priority: priority) {
       try await operation()
     }
   }
 
-  @available(*, deprecated, renamed: "async(priority:operation:)")
+  @available(*, deprecated, renamed: "addTask(priority:operation:)")
   @_alwaysEmitIntoClient
   public mutating func spawn(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
   ) {
-    async(priority: priority, operation: operation)
+    addTask(priority: priority, operation: operation)
   }
 
-  @available(*, deprecated, renamed: "asyncUnlessCancelled(priority:operation:)")
+  @available(*, deprecated, renamed: "addTaskUnlessCancelled(priority:operation:)")
   @_alwaysEmitIntoClient
   public mutating func spawnUnlessCancelled(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
   ) -> Bool {
-    asyncUnlessCancelled(priority: priority, operation: operation)
+    addTaskUnlessCancelled(priority: priority, operation: operation)
+  }
+
+  @available(*, deprecated, renamed: "addTask(priority:operation:)")
+  @_alwaysEmitIntoClient
+  public mutating func async(
+    priority: TaskPriority? = nil,
+    operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
+  ) {
+    addTask(priority: priority, operation: operation)
+  }
+
+  @available(*, deprecated, renamed: "addTaskUnlessCancelled(priority:operation:)")
+  @_alwaysEmitIntoClient
+  public mutating func asyncUnlessCancelled(
+    priority: TaskPriority? = nil,
+    operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
+  ) -> Bool {
+    addTaskUnlessCancelled(priority: priority, operation: operation)
   }
 }
 

stdlib/public/Concurrency/Task.swift

@@ -202,11 +202,20 @@ public struct TaskPriority: RawRepresentable, Sendable {
   }
 
   public static let high: TaskPriority = .init(rawValue: 0x19)
-  public static let userInitiated: TaskPriority = high
-  public static let `default`: TaskPriority = .init(rawValue: 0x15)
+
+  @_alwaysEmitIntoClient
+  public static var medium: TaskPriority {
+    .init(rawValue: 0x15)
+  }
+
   public static let low: TaskPriority = .init(rawValue: 0x11)
+
+  public static let userInitiated: TaskPriority = high
   public static let utility: TaskPriority = low
   public static let background: TaskPriority = .init(rawValue: 0x09)
+
+  @available(*, deprecated, renamed: "medium")
+  public static let `default`: TaskPriority = .init(rawValue: 0x15)
 }
 
 @available(SwiftStdlib 5.5, *)
@@ -606,25 +615,6 @@ extension Task where Failure == Error {
   }
 }
 
-// ==== Async Sleep ------------------------------------------------------------
-
-@available(SwiftStdlib 5.5, *)
-extension Task where Success == Never, Failure == Never {
-  /// Suspends the current task for _at least_ the given duration
-  /// in nanoseconds.
-  ///
-  /// This function does _not_ block the underlying thread.
-  public static func sleep(_ duration: UInt64) async {
-    let currentTask = Builtin.getCurrentAsyncTask()
-    let priority = getJobFlags(currentTask).priority ?? Task.currentPriority._downgradeUserInteractive
-
-    return await Builtin.withUnsafeContinuation { (continuation: Builtin.RawUnsafeContinuation) -> Void in
-      let job = _taskCreateNullaryContinuationJob(priority: Int(priority.rawValue), continuation: continuation)
-      _enqueueJobGlobalWithDelay(duration, job)
-    }
-  }
-}
-
 // ==== Voluntary Suspension -----------------------------------------------------
 
 @available(SwiftStdlib 5.5, *)
@@ -636,6 +626,8 @@ extension Task where Success == Never, Failure == Never {
   /// This is not a perfect cure for starvation;
   /// if the task is the highest-priority task in the system, it might go
   /// immediately back to executing.
+  ///
+  @available(*, deprecated, renamed: "suspend()")
   public static func yield() async {
     let currentTask = Builtin.getCurrentAsyncTask()
     let priority = getJobFlags(currentTask).priority ?? Task.currentPriority._downgradeUserInteractive
@@ -645,6 +637,11 @@ extension Task where Success == Never, Failure == Never {
       _enqueueJobGlobal(job)
     }
   }
+
+  @_alwaysEmitIntoClient
+  public static func suspend() async {
+    await yield()
+  }
 }
 
 // ==== UnsafeCurrentTask ------------------------------------------------------
@@ -715,6 +712,11 @@ public struct UnsafeCurrentTask {
   public var priority: TaskPriority {
     getJobFlags(_task).priority ?? .unspecified
   }
+
+  /// Cancel the current task.
+  public func cancel() {
+    _taskCancel(_task)
+  }
 }
 
 @available(SwiftStdlib 5.5, *)

stdlib/public/Concurrency/TaskCancellation.swift

@@ -112,7 +112,7 @@ public struct CancellationError: Error {
 
 @available(SwiftStdlib 5.5, *)
 @_silgen_name("swift_task_addCancellationHandler")
-func _taskAddCancellationHandler(handler: @Sendable () -> Void) -> UnsafeRawPointer /*CancellationNotificationStatusRecord*/
+func _taskAddCancellationHandler(handler: () -> Void) -> UnsafeRawPointer /*CancellationNotificationStatusRecord*/
 
 @available(SwiftStdlib 5.5, *)
 @_silgen_name("swift_task_removeCancellationHandler")

stdlib/public/Concurrency/TaskGroup.swift

@@ -208,7 +208,7 @@ public struct TaskGroup<ChildTaskResult> {
   ///   - `true` if the operation was added to the group successfully,
   ///     `false` otherwise (e.g. because the group `isCancelled`)
   @_alwaysEmitIntoClient
-  public mutating func async(
+  public mutating func addTask(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async -> ChildTaskResult
   ) {
@@ -242,7 +242,7 @@ public struct TaskGroup<ChildTaskResult> {
   ///   - `true` if the operation was added to the group successfully,
   ///     `false` otherwise (e.g. because the group `isCancelled`)
   @_alwaysEmitIntoClient
-  public mutating func asyncUnlessCancelled(
+  public mutating func addTaskUnlessCancelled(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async -> ChildTaskResult
   ) -> Bool {
@@ -333,7 +333,14 @@ public struct TaskGroup<ChildTaskResult> {
   internal mutating func awaitAllRemainingTasks() async {
     while let _ = await next() {}
   }
-
+
+  /// Wait for all remaining tasks in the task group to complete before
+  /// returning.
+  @_alwaysEmitIntoClient
+  public mutating func waitForAll() async {
+    await awaitAllRemainingTasks()
+  }
+
   /// Query whether the group has any remaining tasks.
   ///
   /// Task groups are always empty upon entry to the `withTaskGroup` body, and
@@ -424,6 +431,18 @@ public struct ThrowingTaskGroup<ChildTaskResult, Failure: Error> {
     }
   }
 
+  @usableFromInline
+  internal mutating func _waitForAll() async throws {
+    while let _ = try await next() { }
+  }
+
+  /// Wait for all remaining tasks in the task group to complete before
+  /// returning.
+  @_alwaysEmitIntoClient
+  public mutating func waitForAll() async throws {
+    while let _ = try await next() { }
+  }
+
   /// Spawn, unconditionally, a child task in the group.
   ///
   /// ### Error handling
@@ -440,7 +459,7 @@ public struct ThrowingTaskGroup<ChildTaskResult, Failure: Error> {
   ///   - `true` if the operation was added to the group successfully,
   ///     `false` otherwise (e.g. because the group `isCancelled`)
   @_alwaysEmitIntoClient
-  public mutating func async(
+  public mutating func addTask(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
   ) {
@@ -474,7 +493,7 @@ public struct ThrowingTaskGroup<ChildTaskResult, Failure: Error> {
   ///   - `true` if the operation was added to the group successfully,
   ///     `false` otherwise (e.g. because the group `isCancelled`)
   @_alwaysEmitIntoClient
-  public mutating func asyncUnlessCancelled(
+  public mutating func addTaskUnlessCancelled(
     priority: TaskPriority? = nil,
     operation: __owned @Sendable @escaping () async throws -> ChildTaskResult
   ) -> Bool {