AutoLazy
Post compile tool using Fody to implement the double-checked locking pattern.
The nuget package 
https://nuget.org/packages/AutoLazy.Fody/
PM> Install-Package AutoLazy.Fody
Works on
- static or instance members
- parameterless methods
- properties
- methods with a single parameter (new)
Contributing
Please read the guidelines before submitting any changes. Thank you!
Example
Turns this
public class MyClass
{
// This would work as a method, e.g. GetSettings(), as well.
[Lazy]
public static Settings Settings
{
get
{
using (var fs = File.Open("settings.xml", FileMode.Open))
{
var serializer = new XmlSerializer(typeof(Settings));
return (Settings)serializer.Deserialize(fs);
}
}
}
[Lazy]
public static Settings GetSettingsFile(string fileName)
{
using (var fs = File.Open(fileName, FileMode.Open))
{
var serializer = new XmlSerializer(typeof(Settings));
return (Settings)serializer.Deserialize(fs);
}
}
}Into something equivalent to this
public class MyClass
{
// begin - fields added by the post-compile step
private static readonly object _syncRoot = new object();
private static volatile Settings _settings;
// end
[Lazy]
public static Settings Settings
{
get
{
// thread-safe double-checked locking pattern generated here
var result = _settings;
if (result == null)
{
lock(_syncRoot)
{
result = _settings;
if (result == null)
{
using (var fs = File.Open("settings.xml", FileMode.Open))
{
var serializer = new XmlSerializer(typeof(Settings));
result = (Settings)serializer.Deserialize(fs);
_settings = result;
}
}
}
}
return result;
}
}
// begin - fields added by post-compile step
private static readonly object _getSettingsFileSyncRoot = new object();
private static volatile Dictionary<string, Settings> _getSettingsFileCache
= new Dictionary<string, Settings>();
// end
[Lazy]
public static Settings GetSettingsFile(string fileName)
{
Settings result;
if (!_getSettingsFileCache.TryGetValue(fileName, out result)) // volatile read
{
lock (_getSettingsFileSyncRoot)
{
if (!_getSettingsFileCache.TryGetValue(fileName, out result))
{
using (var fs = File.Open(fileName, FileMode.Open))
{
var serializer = new XmlSerializer(typeof(Settings));
result = (Settings)serializer.Deserialize(fs);
}
// note - we can't mutate the dictionary after
// exposing it to reads (possibly from other threads)
// therefore, we have to copy the dictionary into a new one
// then expose it by setting _getSettingsFileCache
var newCache = new Dictionary<string, Settings>(_getSettingsFileCache.Count + 1);
newCache.Add(fileName, result);
foreach (var pair in _getSettingsFileCache)
{
newCache.Add(pair.Key, pair.Value);
}
_getSettingsFileCache = newCache; // volatile write
}
}
}
return result;
}
}