@synchronized in Swift

synchronized.swift

import ObjectiveC

@discardableResult
public func synchronized<T>(_ lock: AnyObject, closure: () -> T) -> T {
    let lock_ = lock
    objc_sync_enter(lock_)
    defer { objc_sync_exit(lock_) }

    return closure()
}

Example code:

func foo() {
    synchronized(self) {
        // do something
    }
}