Convenient macOS/iOS/etc version checking at runtime

OSVersion.swift

//
//  OSVersion.swift
//  Created by Seth Willits on 4/12/18.
//
//  if runtimeOSVersion.isAtLeast(10, 12) { ... }

import Foundation


var runtimeOSVersion: OperatingSystemVersion {
    return ProcessInfo.processInfo.operatingSystemVersion
} 


extension OperatingSystemVersion: Comparable, Equatable {
    
    init(_ major: Int, _ minor: Int, _ patch: Int) {
        self.init(majorVersion: major, minorVersion: minor, patchVersion: patch)
    }
    
    
    func `is`(_ major: Int, _ minor: Int, _ patch: Int? = nil) -> Bool {
        let v1 = (patch == nil) ? self.majorMinor : self
        let v2 = OperatingSystemVersion(major, minor, patch ?? 0)
        return v1 == v2
    }
    
    
    func isAtLeast(_ major: Int, _ minor: Int, _ patch: Int? = nil) -> Bool {
        let v1 = (patch == nil) ? self.majorMinor : self
        let v2 = OperatingSystemVersion(major, minor, patch ?? 0)
        return v1 >= v2
    }
    
    
    func isAfter(_ major: Int, _ minor: Int, _ patch: Int? = nil) -> Bool {
        let v1 = (patch == nil) ? self.majorMinor : self
        let v2 = OperatingSystemVersion(major, minor, patch ?? 0)
        return v1 > v2
    }
    
    
    func isBefore(_ major: Int, _ minor: Int, _ patch: Int? = nil) -> Bool {
        let v1 = (patch == nil) ? self.majorMinor : self
        let v2 = OperatingSystemVersion(major, minor, patch ?? 0)
        return v1 < v2
    }
    
    
    public static func < (lhs: OperatingSystemVersion, rhs: OperatingSystemVersion) -> Bool {
        return lhs.asUInt32 < rhs.asUInt32
    }
    
    
    public static func == (lhs: OperatingSystemVersion, rhs: OperatingSystemVersion) -> Bool {
        return lhs.asUInt32 == rhs.asUInt32
    }
    
    
    private var majorMinor: OperatingSystemVersion {
        return OperatingSystemVersion(majorVersion, minorVersion, 0)
    }
    
    
    private var asUInt32: UInt32 {
        return ((0xFF & UInt32(majorVersion)) << 16) | ((0xFF & UInt32(minorVersion)) << 8) | ((0xFF & UInt32(patchVersion)))
    }
}

let v1 = OperatingSystemVersion(10, 1, 6)
let v2 = OperatingSystemVersion(10, 2, 4)
let v3 = OperatingSystemVersion(10, 2, 5)
let v4 = OperatingSystemVersion(10, 3, 1)

assert(v1 < v2)
assert(v2 < v3)
assert(v2 != v3)
assert(v3 > v2)
assert(v2 != v3)

assert(v1.is(10, 1))
assert(v1.is(10, 1, 6))
assert(!v1.is(10, 1, 7))

assert(v2.isAtLeast(10, 1))
assert(v2.isAtLeast(10, 1, 5))
assert(v2.isAtLeast(10, 2))
assert(v2.isAtLeast(10, 2, 1))
assert(v2.isAtLeast(10, 2, 4))
assert(!v2.isAtLeast(10, 3))
assert(!v2.isAtLeast(10, 3, 1))

assert(v2.isAfter(10, 1))
assert(v2.isAfter(10, 2, 3))
assert(!v2.isAfter(10, 2, 7))

assert(v2.isBefore(10, 3))
assert(v2.isBefore(10, 2, 9))
assert(!v2.isBefore(10, 2, 4))
assert(!v2.isBefore(10, 1, 4))