Move AsyncOperation into Operations static library and add separate tests

1 files changed, 96 insertions, 0 deletions

diff --git a/ios/Operations/InputInjectionBuilder.swift b/ios/Operations/InputInjectionBuilder.swift
new file mode 100644
index 0000000000..ad2f329024
--- /dev/null
+++ b/ios/Operations/InputInjectionBuilder.swift
@@ -0,0 +1,96 @@
+//
+//  InputInjectionBuilder.swift
+//  MullvadVPN
+//
+//  Created by pronebird on 09/06/2022.
+//  Copyright © 2022 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+
+public protocol OperationInputContext {
+    associatedtype Input
+
+    func reduce() -> Input?
+}
+
+public final class InputInjectionBuilder<OperationType, Context>
+    where OperationType: InputOperation
+{
+    public typealias InputBlock = (inout Context) -> Void
+
+    private let operation: OperationType
+    private var context: Context
+    private var inputBlocks: [InputBlock] = []
+
+    public init(operation: OperationType, context: Context) {
+        self.operation = operation
+        self.context = context
+    }
+
+    public func inject<T>(
+        from dependency: T,
+        assignOutputTo keyPath: WritableKeyPath<Context, T.Output?>
+    ) -> Self
+        where T: OutputOperation
+    {
+        return inject(from: dependency) { context, output in
+            context[keyPath: keyPath] = output
+        }
+    }
+
+    public func inject<T>(
+        from dependency: T,
+        via block: @escaping (inout Context, T.Output) -> Void
+    ) -> Self
+        where T: OutputOperation
+    {
+        inputBlocks.append { context in
+            if let output = dependency.output {
+                block(&context, output)
+            }
+        }
+
+        operation.addDependency(dependency)
+
+        return self
+    }
+
+    public func injectCompletion<T, Success, Failure>(
+        from dependency: T,
+        via block: @escaping (inout Context, T.Completion) -> Void
+    ) -> Self
+        where T: ResultOperation<Success, Failure>
+    {
+        inputBlocks.append { context in
+            if let completion = dependency.completion {
+                block(&context, completion)
+            }
+        }
+
+        operation.addDependency(dependency)
+
+        return self
+    }
+
+    public func reduce(_ reduceBlock: @escaping (Context) -> OperationType.Input?) {
+        operation.setInputBlock {
+            for inputBlock in self.inputBlocks {
+                inputBlock(&self.context)
+            }
+
+            return reduceBlock(self.context)
+        }
+    }
+}
+
+public extension InputInjectionBuilder
+    where Context: OperationInputContext,
+    Context.Input == OperationType.Input
+{
+    func reduce() {
+        reduce { context in
+            return context.reduce()
+        }
+    }
+}