From f9c665a542448da5152c96cddbb7878a518f5f13 Mon Sep 17 00:00:00 2001
From: Erik <nuclear.ace@gmail.com>
Date: Mon, 25 Jan 2016 17:23:57 -0500
Subject: [PATCH] for whatever reason I was able trigger a race condition
 because of the last commit

---
 Source/SwiftRegex.swift | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Source/SwiftRegex.swift b/Source/SwiftRegex.swift
index 8ea2d0e..b7c134b 100644
--- a/Source/SwiftRegex.swift
+++ b/Source/SwiftRegex.swift
@@ -15,6 +15,7 @@ import Foundation
 
 infix operator <~ { associativity none precedence 130 }
 
+private let lock = dispatch_semaphore_create(1)
 private var swiftRegexCache = [String: NSRegularExpression]()
 
 internal final class SwiftRegex: NSObject, BooleanType {
@@ -22,6 +23,10 @@ internal final class SwiftRegex: NSObject, BooleanType {
     var regex: NSRegularExpression
     
     init(target:String, pattern:String, options:NSRegularExpressionOptions?) {
+        if dispatch_semaphore_wait(lock, dispatch_time(DISPATCH_TIME_NOW, Int64(10 * NSEC_PER_MSEC))) != 0 {
+            fatalError("This should never happen")
+        }
+        
         self.target = target
         if let regex = swiftRegexCache[pattern] {
             self.regex = regex
@@ -36,6 +41,7 @@ internal final class SwiftRegex: NSObject, BooleanType {
                 self.regex = NSRegularExpression()
             }
         }
+        dispatch_semaphore_signal(lock)
         super.init()
     }