Move AsyncOperation into Operations static library and add separate tests

1 files changed, 138 insertions, 0 deletions

diff --git a/ios/Operations/TransformOperation.swift b/ios/Operations/TransformOperation.swift
new file mode 100644
index 0000000000..71cac93f4b
--- /dev/null
+++ b/ios/Operations/TransformOperation.swift
@@ -0,0 +1,138 @@
+//
+//  TransformOperation.swift
+//  AsyncOperationQueueTest
+//
+//  Created by pronebird on 31/05/2022.
+//
+
+import Foundation
+
+public final class TransformOperation<Input, Output, Failure: Error>:
+    ResultOperation<Output, Failure>,
+    InputOperation
+{
+    public typealias ExecutionBlock = (Input, TransformOperation<Input, Output, Failure>) -> Void
+    public typealias ThrowingExecutionBlock = (Input) throws -> Output
+    public typealias InputBlock = () -> Input?
+
+    private let nslock = NSLock()
+
+    public var input: Input? {
+        return _input
+    }
+
+    private var __input: Input?
+    private var _input: Input? {
+        get {
+            nslock.lock()
+            defer { nslock.unlock() }
+            return __input
+        }
+        set {
+            nslock.lock()
+            __input = newValue
+            nslock.unlock()
+        }
+    }
+
+    private var inputBlock: InputBlock?
+
+    private var executionBlock: ExecutionBlock?
+    private var cancellationBlocks: [() -> Void] = []
+
+    public init(
+        dispatchQueue: DispatchQueue? = nil,
+        input: Input? = nil,
+        block: ExecutionBlock? = nil
+    ) {
+        __input = input
+        executionBlock = block
+
+        super.init(dispatchQueue: dispatchQueue)
+    }
+
+    public init(
+        dispatchQueue: DispatchQueue? = nil,
+        input: Input? = nil,
+        throwingBlock: @escaping ThrowingExecutionBlock
+    ) {
+        __input = input
+        executionBlock = Self.wrapThrowingBlock(throwingBlock)
+
+        super.init(dispatchQueue: dispatchQueue)
+    }
+
+    override public func main() {
+        let inputValue = inputBlock?()
+
+        _input = inputValue
+
+        guard let inputValue = inputValue, let executionBlock = executionBlock else {
+            finish(completion: .cancelled)
+            return
+        }
+
+        executionBlock(inputValue, self)
+    }
+
+    override public func operationDidCancel() {
+        let blocks = cancellationBlocks
+        cancellationBlocks.removeAll()
+
+        for block in blocks {
+            block()
+        }
+    }
+
+    override public func operationDidFinish() {
+        cancellationBlocks.removeAll()
+        executionBlock = nil
+    }
+
+    // MARK: - Block handlers
+
+    public func setExecutionBlock(_ block: @escaping ExecutionBlock) {
+        dispatchQueue.async {
+            assert(!self.isExecuting && !self.isFinished)
+            self.executionBlock = block
+        }
+    }
+
+    public func setExecutionBlock(_ block: @escaping ThrowingExecutionBlock) {
+        setExecutionBlock(Self.wrapThrowingBlock(block))
+    }
+
+    public func addCancellationBlock(_ block: @escaping () -> Void) {
+        dispatchQueue.async {
+            if self.isCancelled {
+                block()
+            } else {
+                self.cancellationBlocks.append(block)
+            }
+        }
+    }
+
+    // MARK: - Input injection
+
+    public func setInputBlock(_ block: @escaping () -> Input?) {
+        dispatchQueue.async {
+            self.inputBlock = block
+        }
+    }
+
+    private class func wrapThrowingBlock(_ executionBlock: @escaping ThrowingExecutionBlock)
+        -> ExecutionBlock
+    {
+        return { input, operation in
+            do {
+                let value = try executionBlock(input)
+
+                operation.finish(completion: .success(value))
+            } catch {
+                let castedError = error as! Failure
+
+                operation.finish(completion: .failure(castedError))
+            }
+        }
+    }
+}