Move AsyncOperation into Operations static library and add separate tests

1 files changed, 120 insertions, 0 deletions

diff --git a/ios/Operations/ResultBlockOperation.swift b/ios/Operations/ResultBlockOperation.swift
new file mode 100644
index 0000000000..483731360a
--- /dev/null
+++ b/ios/Operations/ResultBlockOperation.swift
@@ -0,0 +1,120 @@
+//
+//  ResultBlockOperation.swift
+//  MullvadVPN
+//
+//  Created by pronebird on 12/05/2022.
+//  Copyright © 2022 Mullvad VPN AB. All rights reserved.
+//
+
+import Foundation
+
+public final class ResultBlockOperation<Success, Failure: Error>: ResultOperation<
+    Success,
+    Failure
+> {
+    public typealias ExecutionBlock = (ResultBlockOperation<Success, Failure>) -> Void
+    public typealias ThrowingExecutionBlock = () throws -> Success
+
+    private var executionBlock: ExecutionBlock?
+    private var cancellationBlocks: [() -> Void] = []
+
+    public convenience init(
+        dispatchQueue: DispatchQueue? = nil,
+        executionBlock: ExecutionBlock? = nil
+    ) {
+        self.init(
+            dispatchQueue: dispatchQueue,
+            executionBlock: executionBlock,
+            completionQueue: nil,
+            completionHandler: nil
+        )
+    }
+
+    public convenience init(
+        dispatchQueue: DispatchQueue? = nil,
+        executionBlock: @escaping ThrowingExecutionBlock
+    ) {
+        self.init(
+            dispatchQueue: dispatchQueue,
+            executionBlock: Self.wrapThrowingBlock(executionBlock),
+            completionQueue: nil,
+            completionHandler: nil
+        )
+    }
+
+    public init(
+        dispatchQueue: DispatchQueue?,
+        executionBlock: ExecutionBlock?,
+        completionQueue: DispatchQueue?,
+        completionHandler: CompletionHandler?
+    ) {
+        self.executionBlock = executionBlock
+
+        super.init(
+            dispatchQueue: dispatchQueue,
+            completionQueue: completionQueue,
+            completionHandler: completionHandler
+        )
+    }
+
+    override public func main() {
+        let block = executionBlock
+        executionBlock = nil
+
+        block?(self)
+    }
+
+    override public func operationDidCancel() {
+        let blocks = cancellationBlocks
+        cancellationBlocks.removeAll()
+
+        for block in blocks {
+            block()
+        }
+    }
+
+    override public func operationDidFinish() {
+        cancellationBlocks.removeAll()
+        executionBlock = nil
+    }
+
+    public func setExecutionBlock(
+        _ block: @escaping (ResultBlockOperation<Success, Failure>)
+            -> Void
+    ) {
+        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)
+            }
+        }
+    }
+
+    private class func wrapThrowingBlock(_ executionBlock: @escaping ThrowingExecutionBlock)
+        -> ExecutionBlock
+    {
+        return { operation in
+            do {
+                let value = try executionBlock()
+
+                operation.finish(completion: .success(value))
+            } catch {
+                let castedError = error as! Failure
+
+                operation.finish(completion: .failure(castedError))
+            }
+        }
+    }
+}