UnfairLockPointer.swift

public final class UnfairLockPointer {
  
  deinit {
    pointer.deinitialize(count: 1)
    pointer.deallocate()
  }
  
  private let pointer: os_unfair_lock_t
  
  public init() {
    // We will directly supply this pointer instead of using
    // the `&` operator when calling lock/unlock functions.
    // See: http://www.russbishop.net/the-law
    pointer = os_unfair_lock_t.allocate(capacity: 1)
    pointer.initialize(to: os_unfair_lock())
  }
    
  public func lock() {
    os_unfair_lock_lock(pointer)
  }
  
  public func tryLock() -> Bool {
    os_unfair_lock_trylock(pointer)
  }
  
  public func unlock() {
    os_unfair_lock_unlock(pointer)
  }
  
  public func assertOwned() {
    os_unfair_lock_assert_owner(pointer)
  }
  
  public func assertNotOwned() {
    os_unfair_lock_assert_not_owner(pointer)
  }
  
}