introduce WorkflowActionCore superprotocol

Workflow/Sources/AnyWorkflow.swift

@@ -91,7 +91,7 @@ extension AnyWorkflow {
     /// That type information *is* present in our storage object, however, so we
     /// pass the context down to that storage object which will ultimately call
     /// through to `context.render(workflow:key:reducer:)`.
-    internal func render<Parent, Action>(context: RenderContext<Parent>, key: String, outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowAction, Action.WorkflowType == Parent {
+    internal func render<Parent, Action>(context: RenderContext<Parent>, key: String, outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowActionCore, Action.WorkflowType == Parent {
         return storage.render(context: context, key: key, outputMap: outputMap)
     }
 }
@@ -103,7 +103,7 @@ extension AnyWorkflow {
     fileprivate class AnyStorage {
         var base: Any { fatalError() }
 
-        func render<Parent, Action>(context: RenderContext<Parent>, key: String, outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowAction, Action.WorkflowType == Parent {
+        func render<Parent, Action>(context: RenderContext<Parent>, key: String, outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowActionCore, Action.WorkflowType == Parent {
             fatalError()
         }
 
@@ -140,7 +140,7 @@ extension AnyWorkflow {
             return T.self
         }
 
-        override func render<Parent, Action>(context: RenderContext<Parent>, key: String, outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowAction, Action.WorkflowType == Parent {
+        override func render<Parent, Action>(context: RenderContext<Parent>, key: String, outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowActionCore, Action.WorkflowType == Parent {
             let outputMap: (T.Output) -> Action = { [outputTransform] output in
                 outputMap(outputTransform(output))
             }

Workflow/Sources/AnyWorkflowConvertible.swift

@@ -37,11 +37,11 @@ extension AnyWorkflowConvertible {
     /// - Parameter key: A string that uniquely identifies this workflow.
     ///
     /// - Returns: The `Rendering` generated by the workflow.
-    public func rendered<Parent>(in context: RenderContext<Parent>, key: String = "") -> Rendering where Output: WorkflowAction, Output.WorkflowType == Parent {
+    public func rendered<Parent>(in context: RenderContext<Parent>, key: String = "") -> Rendering where Output: WorkflowActionCore, Output.WorkflowType == Parent {
         return asAnyWorkflow().render(context: context, key: key, outputMap: { $0 })
     }
 
-    public func rendered<Parent, Action>(in context: RenderContext<Parent>, key: String = "", outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowAction, Action.WorkflowType == Parent {
+    public func rendered<Parent, Action>(in context: RenderContext<Parent>, key: String = "", outputMap: @escaping (Output) -> Action) -> Rendering where Action: WorkflowActionCore, Action.WorkflowType == Parent {
         return asAnyWorkflow().render(context: context, key: key, outputMap: { outputMap($0) })
     }
 
@@ -73,12 +73,12 @@ extension AnyWorkflowConvertible where Output == Never {
 }
 
 extension AnyWorkflowConvertible where Rendering == Void {
-    public func running<Parent, Action>(in context: RenderContext<Parent>, key: String = "", outputMap: @escaping (Output) -> Action) where Action: WorkflowAction, Action.WorkflowType == Parent {
+    public func running<Parent, Action>(in context: RenderContext<Parent>, key: String = "", outputMap: @escaping (Output) -> Action) where Action: WorkflowActionCore, Action.WorkflowType == Parent {
         rendered(in: context, key: key, outputMap: outputMap)
     }
 }
 
-extension AnyWorkflowConvertible where Rendering == Void, Output: WorkflowAction {
+extension AnyWorkflowConvertible where Rendering == Void, Output: WorkflowActionCore {
     public func running<Parent>(in context: RenderContext<Parent>, key: String = "") where Output.WorkflowType == Parent {
         rendered(in: context, key: key)
     }

Workflow/Sources/RenderContext.swift

@@ -63,7 +63,7 @@ public class RenderContext<WorkflowType: Workflow>: RenderContextType {
     /// - Parameter key: A string that uniquely identifies this child.
     ///
     /// - Returns: The `Rendering` result of the child's `render` method.
-    func render<Child, Action>(workflow: Child, key: String, outputMap: @escaping (Child.Output) -> Action) -> Child.Rendering where Child: Workflow, Action: WorkflowAction, WorkflowType == Action.WorkflowType {
+    func render<Child, Action>(workflow: Child, key: String, outputMap: @escaping (Child.Output) -> Action) -> Child.Rendering where Child: Workflow, Action: WorkflowActionCore, WorkflowType == Action.WorkflowType {
         fatalError()
     }
 
@@ -77,7 +77,7 @@ public class RenderContext<WorkflowType: Workflow>: RenderContextType {
     ///
     /// - Parameter actionType: The type of Action this Sink may process
     /// - Returns: A Sink capable of relaying `Action` instances to the Workflow runtime
-    public func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where Action: WorkflowAction, Action.WorkflowType == WorkflowType {
+    public func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where Action: WorkflowActionCore, Action.WorkflowType == WorkflowType {
         fatalError()
     }
 
@@ -118,12 +118,12 @@ public class RenderContext<WorkflowType: Workflow>: RenderContextType {
             super.init()
         }
 
-        override func render<Child, Action>(workflow: Child, key: String, outputMap: @escaping (Child.Output) -> Action) -> Child.Rendering where WorkflowType == Action.WorkflowType, Child: Workflow, Action: WorkflowAction {
+        override func render<Child, Action>(workflow: Child, key: String, outputMap: @escaping (Child.Output) -> Action) -> Child.Rendering where WorkflowType == Action.WorkflowType, Child: Workflow, Action: WorkflowActionCore {
             assertStillValid()
             return implementation.render(workflow: workflow, key: key, outputMap: outputMap)
         }
 
-        override func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where WorkflowType == Action.WorkflowType, Action: WorkflowAction {
+        override func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where WorkflowType == Action.WorkflowType, Action: WorkflowActionCore {
             assertStillValid()
             return implementation.makeSink(of: actionType)
         }
@@ -142,9 +142,9 @@ public class RenderContext<WorkflowType: Workflow>: RenderContextType {
 internal protocol RenderContextType: AnyObject {
     associatedtype WorkflowType: Workflow
 
-    func render<Child, Action>(workflow: Child, key: String, outputMap: @escaping (Child.Output) -> Action) -> Child.Rendering where Child: Workflow, Action: WorkflowAction, Action.WorkflowType == WorkflowType
+    func render<Child, Action>(workflow: Child, key: String, outputMap: @escaping (Child.Output) -> Action) -> Child.Rendering where Child: Workflow, Action: WorkflowActionCore, Action.WorkflowType == WorkflowType
 
-    func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where Action: WorkflowAction, Action.WorkflowType == WorkflowType
+    func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where Action: WorkflowActionCore, Action.WorkflowType == WorkflowType
 
     func runSideEffect(key: AnyHashable, action: (_ lifetime: Lifetime) -> Void)
 }

Workflow/Sources/Sink.swift

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-/// Sink is a type that receives incoming values (commonly events or `WorkflowAction`)
+/// Sink is a type that receives incoming values (commonly events or `WorkflowActionCore`)
 ///
 /// Use `RenderContext.makeSink` to create instances.
 public struct Sink<Value> {

Workflow/Sources/SubtreeManager.swift

@@ -128,7 +128,7 @@ extension WorkflowNode {
 
 extension WorkflowNode.SubtreeManager {
     enum Output {
-        case update(any WorkflowAction<WorkflowType>, source: WorkflowUpdateDebugInfo.Source)
+        case update(any WorkflowActionCore<WorkflowType>, source: WorkflowUpdateDebugInfo.Source)
         case childDidUpdate(WorkflowUpdateDebugInfo)
     }
 }
@@ -178,7 +178,7 @@ extension WorkflowNode.SubtreeManager {
             outputMap: @escaping (Child.Output) -> Action
         ) -> Child.Rendering
             where Child: Workflow,
-            Action: WorkflowAction,
+            Action: WorkflowActionCore,
             WorkflowType == Action.WorkflowType {
             /// A unique key used to identify this child workflow
             let childKey = ChildKey(childType: Child.self, key: key)
@@ -227,7 +227,7 @@ extension WorkflowNode.SubtreeManager {
             return child.render()
         }
 
-        func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where Action: WorkflowAction, WorkflowType == Action.WorkflowType {
+        func makeSink<Action>(of actionType: Action.Type) -> Sink<Action> where Action: WorkflowActionCore, WorkflowType == Action.WorkflowType {
             let reusableSink = sinkStore.findOrCreate(actionType: Action.self)
 
             let sink = Sink<Action> { [weak reusableSink] action in
@@ -270,7 +270,7 @@ extension WorkflowNode.SubtreeManager {
             self.usedSinks = [:]
         }
 
-        mutating func findOrCreate<Action: WorkflowAction>(actionType: Action.Type) -> ReusableSink<Action> {
+        mutating func findOrCreate<Action: WorkflowActionCore>(actionType: Action.Type) -> ReusableSink<Action> {
             let key = ObjectIdentifier(actionType)
 
             let reusableSink: ReusableSink<Action>
@@ -302,7 +302,7 @@ extension WorkflowNode.SubtreeManager {
         }
     }
 
-    fileprivate final class ReusableSink<Action: WorkflowAction>: AnyReusableSink where Action.WorkflowType == WorkflowType {
+    fileprivate final class ReusableSink<Action: WorkflowActionCore>: AnyReusableSink where Action.WorkflowType == WorkflowType {
         func handle(action: Action) {
             let output = Output.update(action, source: .external)
 
@@ -445,11 +445,11 @@ extension WorkflowNode.SubtreeManager {
 
     fileprivate final class ChildWorkflow<W: Workflow>: AnyChildWorkflow {
         private let node: WorkflowNode<W>
-        private var outputMap: (W.Output) -> any WorkflowAction<WorkflowType>
+        private var outputMap: (W.Output) -> any WorkflowActionCore<WorkflowType>
 
         init(
             workflow: W,
-            outputMap: @escaping (W.Output) -> any WorkflowAction<WorkflowType>,
+            outputMap: @escaping (W.Output) -> any WorkflowActionCore<WorkflowType>,
             eventPipe: EventPipe,
             key: String,
             parentSession: WorkflowSession?,
@@ -480,7 +480,7 @@ extension WorkflowNode.SubtreeManager {
 
         func update(
             workflow: W,
-            outputMap: @escaping (W.Output) -> any WorkflowAction<WorkflowType>,
+            outputMap: @escaping (W.Output) -> any WorkflowActionCore<WorkflowType>,
             eventPipe: EventPipe
         ) {
             self.outputMap = outputMap

Workflow/Sources/WorkflowAction.swift

@@ -14,12 +14,18 @@
  * limitations under the License.
  */
 
-/// Conforming types represent an action that advances a workflow. When applied, an action emits the next
-/// state and / or output for the workflow.
-public protocol WorkflowAction<WorkflowType> {
+// TODO: document this
+public protocol WorkflowActionCore<WorkflowType> {
     /// The type of workflow that this action can be applied to.
     associatedtype WorkflowType: Workflow
 
+    // TODO: document this
+    func apply(toState state: inout WorkflowType.State, workflow: WorkflowType) -> WorkflowType.Output?
+}
+
+/// Conforming types represent an action that advances a workflow. When applied, an action emits the next
+/// state and / or output for the workflow.
+public protocol WorkflowAction: WorkflowActionCore {
     /// Applies this action to a given state of the workflow, optionally returning an output event.
     ///
     /// - Parameter state: The current state of the workflow. The state is passed as an `inout` param, allowing actions
@@ -30,11 +36,17 @@ public protocol WorkflowAction<WorkflowType> {
     func apply(toState state: inout WorkflowType.State) -> WorkflowType.Output?
 }
 
+public extension WorkflowActionCore where Self: WorkflowAction {
+    func apply(toState state: inout WorkflowType.State, workflow: WorkflowType) -> WorkflowType.Output? {
+        apply(toState: &state)
+    }
+}
+
 /// A type-erased workflow action.
 ///
 /// The `AnyWorkflowAction` type forwards `apply` to an underlying workflow action, hiding its specific underlying type.
-public struct AnyWorkflowAction<WorkflowType: Workflow>: WorkflowAction {
-    private let _apply: (inout WorkflowType.State) -> WorkflowType.Output?
+public struct AnyWorkflowAction<WorkflowType: Workflow>: WorkflowActionCore {
+    private let _apply: (inout WorkflowType.State, WorkflowType) -> WorkflowType.Output?
 
     /// The underlying type-erased `WorkflowAction`
     public let base: Any
@@ -50,7 +62,7 @@ public struct AnyWorkflowAction<WorkflowType: Workflow>: WorkflowAction {
             self = anyEvent
             return
         }
-        self._apply = { return base.apply(toState: &$0) }
+        self._apply = base.apply
         self.base = base
         self.isClosureBased = false
     }
@@ -62,6 +74,21 @@ public struct AnyWorkflowAction<WorkflowType: Workflow>: WorkflowAction {
         _ apply: @escaping (inout WorkflowType.State) -> WorkflowType.Output?,
         fileID: StaticString = #fileID,
         line: UInt = #line
+    ) {
+        self.init(
+            { state, _ in apply(&state) },
+            fileID: fileID,
+            line: line
+        )
+    }
+
+    /// Creates a type-erased workflow action with the given `apply` implementation.
+    ///
+    /// - Parameter apply: the apply function for the resulting action.
+    public init(
+        _ apply: @escaping (inout WorkflowType.State, WorkflowType) -> WorkflowType.Output?,
+        fileID: StaticString = #fileID,
+        line: UInt = #line
     ) {
         let closureAction = ClosureAction<WorkflowType>(
             _apply: apply,
@@ -74,13 +101,13 @@ public struct AnyWorkflowAction<WorkflowType: Workflow>: WorkflowAction {
     /// Private initializer forwarded to via `init(_ apply:...)`
     /// - Parameter closureAction: The `ClosureAction` wrapping the underlying `apply` closure.
     fileprivate init(closureAction: ClosureAction<WorkflowType>) {
-        self._apply = closureAction.apply(toState:)
+        self._apply = closureAction.apply(toState:workflow:)
         self.base = closureAction
         self.isClosureBased = true
     }
 
-    public func apply(toState state: inout WorkflowType.State) -> WorkflowType.Output? {
-        return _apply(&state)
+    public func apply(toState state: inout WorkflowType.State, workflow: WorkflowType) -> WorkflowType.Output? {
+        return _apply(&state, workflow)
     }
 }
 
@@ -108,13 +135,13 @@ extension AnyWorkflowAction {
 /// A `WorkflowAction` that wraps an `apply(...)` implementation defined by a closure.
 /// Mainly used to provide more useful debugging/telemetry information for `AnyWorkflow` instances
 /// defined via a closure.
-struct ClosureAction<WorkflowType: Workflow>: WorkflowAction {
-    private let _apply: (inout WorkflowType.State) -> WorkflowType.Output?
+struct ClosureAction<WorkflowType: Workflow>: WorkflowActionCore {
+    private let _apply: (inout WorkflowType.State, WorkflowType) -> WorkflowType.Output?
     let fileID: StaticString
     let line: UInt
 
     init(
-        _apply: @escaping (inout WorkflowType.State) -> WorkflowType.Output?,
+        _apply: @escaping (inout WorkflowType.State, WorkflowType) -> WorkflowType.Output?,
         fileID: StaticString,
         line: UInt
     ) {
@@ -123,8 +150,8 @@ struct ClosureAction<WorkflowType: Workflow>: WorkflowAction {
         self.line = line
     }
 
-    func apply(toState state: inout WorkflowType.State) -> WorkflowType.Output? {
-        _apply(&state)
+    func apply(toState state: inout WorkflowType.State, workflow: WorkflowType) -> WorkflowType.Output? {
+        _apply(&state, workflow)
     }
 }
 

Workflow/Sources/WorkflowLogger.swift

@@ -113,7 +113,7 @@ final class WorkflowLogger {
         os_signpost(.end, log: .active, name: "Alive", signpostID: signpostID)
     }
 
-    static func logSinkEvent<Action: WorkflowAction>(ref: AnyObject, action: Action) {
+    static func logSinkEvent<Action: WorkflowActionCore>(ref: AnyObject, action: Action) {
         guard WorkflowLogging.config.logActions else { return }
 
         let signpostID = OSSignpostID(log: .active, object: ref)

Workflow/Sources/WorkflowNode.swift

@@ -80,7 +80,7 @@ final class WorkflowNode<WorkflowType: Workflow> {
 
         switch subtreeOutput {
         case .update(let action, let source):
-            /// 'Opens' the existential `any WorkflowAction<WorkflowType>` value
+            /// 'Opens' the existential `any WorkflowActionCore<WorkflowType>` value
             /// allowing the underlying conformance to be applied to the Workflow's State
             let outputEvent = openAndApply(
                 action,
@@ -178,12 +178,12 @@ extension WorkflowNode {
 }
 
 private extension WorkflowNode {
-    /// Applies an appropriate `WorkflowAction` to advance the underlying Workflow `State`
+    /// Applies an appropriate `WorkflowActionCore` to advance the underlying Workflow `State`
     /// - Parameters:
-    ///   - action: The `WorkflowAction` to apply
+    ///   - action: The `WorkflowActionCore` to apply
     ///   - isExternal: Whether the handled action came from the 'outside world' vs being bubbled up from a child node
     /// - Returns: An optional `Output` produced by the action application
-    func openAndApply<A: WorkflowAction>(
+    func openAndApply<A: WorkflowActionCore>(
         _ action: A,
         isExternal: Bool
     ) -> WorkflowType.Output? where A.WorkflowType == WorkflowType {
@@ -208,7 +208,7 @@ private extension WorkflowNode {
         defer { observerCompletion?(state, output) }
 
         /// Apply the action to the current state
-        output = action.apply(toState: &state)
+        output = action.apply(toState: &state, workflow: workflow)
 
         return output
     }