5 // Jérémie "Garuma" Laval <jeremie.laval@gmail.com>
7 // Copyright (c) 2009 Jérémie "Garuma" Laval
9 // Permission is hereby granted, free of charge, to any person obtaining a copy
10 // of this software and associated documentation files (the "Software"), to deal
11 // in the Software without restriction, including without limitation the rights
12 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13 // copies of the Software, and to permit persons to whom the Software is
14 // furnished to do so, subject to the following conditions:
16 // The above copyright notice and this permission notice shall be included in
17 // all copies or substantial portions of the Software.
19 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
22 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
27 #if NET_4_0 || BOOTSTRAP_NET_4_0
31 namespace System.Threading
33 public static class LazyInitializer
35 public static T EnsureInitialized<T> (ref T target) where T : class
37 return EnsureInitialized (ref target, GetDefaultCtorValue<T>);
40 public static T EnsureInitialized<T> (ref T target, Func<T> initFunc) where T : class
42 Interlocked.CompareExchange (ref target, initFunc (), null);
47 public static T EnsureInitialized<T> (ref T target, ref bool initialized, ref object syncRoot)
49 return EnsureInitialized (ref target, ref initialized, ref syncRoot, GetDefaultCtorValue<T>);
52 public static T EnsureInitialized<T> (ref T target, ref bool initialized, ref object syncRoot, Func<T> initFunc)
59 return target = initFunc ();
63 internal static T GetDefaultCtorValue<T> ()
66 return Activator.CreateInstance<T> ();
68 throw new MissingMemberException ("The type being lazily initialized does not have a "
69 + "public, parameterless constructor.");