LenseTest

inlining.swift

//
//  Inlining.swift
//  Benchmarks
//
//  Created by Anders on 13/8/2016.
//  Copyright © 2016 Anders. All rights reserved.
//

import XCTest

struct SuperStruct {
	var field0 = 0
	var field1 = 1
	var field2 = 2
	var field3 = 3
	var field4 = 4
	var field5 = 5
	var field6 = 6
	var field7 = 7
}

class Inlining: XCTestCase {
	func testPerformanceInlined() {
		let value = TestAtomic(SuperStruct())
		var isValueCorrect = true

		measure {
			for _ in 0 ..< 1000000 {
				isValueCorrect = isValueCorrect && value.withValue { $0.field1 } == 1
			}

			XCTAssert(isValueCorrect)
		}
	}

	func testPerformanceNormal() {
		let value = TestAtomic(SuperStruct())
		let lense = test(value: value)
		var isValueCorrect = true

		measure {
			for _ in 0 ..< 1000000 {
				isValueCorrect = isValueCorrect && lense() == 1
			}

			XCTAssert(isValueCorrect)
		}
	}

	func testPerformanceValueLense() {
		let value = TestAtomic(SuperStruct())
		let lense = test2(value: value)
		var isValueCorrect = true

		measure {
			for _ in 0 ..< 1000000 {
				isValueCorrect = isValueCorrect && lense.value == 1
			}

			XCTAssert(isValueCorrect)
		}
	}
}

public final class ValueLense {
	let _atomic: TestAtomic<SuperStruct>

	var value: Int {
		return _atomic.withValue { $0.field1 }
	}

	init(_ atomic: TestAtomic<SuperStruct>) {
		_atomic = atomic
	}
}

func test(value: TestAtomic<SuperStruct>) -> () -> Int {
	return { value.withValue { $0.field1 } }
}

func test2(value: TestAtomic<SuperStruct>) -> ValueLense {
	return ValueLense(value)
}

public final class TestAtomic<Value> {
	private var _value: Value

	public init(_ value: Value) {
		_value = value
	}

//	@inline(__always)
	public func inlinedWithValue<Result>(_ action: @noescape (inout Value) throws -> Result) rethrows -> Result {
		return try action(&_value)
	}

//	@inline(never)
	public func withValue<Result>(_ action: @noescape (Value) throws -> Result) rethrows -> Result {
		return try action(_value)
	}
}