private T NoneMode(HashSet <Thread> threads, Func <T> valueFactory)
{
if (Volatile.Read(ref _isValueCreated) != 0)
{
return(_valueFactory.Invoke());
}
try
{
AddThread(threads);
ValueForDebugDisplay = valueFactory();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
Volatile.Write(ref _isValueCreated, 1);
return(ValueForDebugDisplay);
}
catch (Exception)
{
Volatile.Write(ref _isValueCreated, 0);
throw;
}
finally
{
RemoveThread(threads);
}
}
private T CachingFullMode(Func <T> valueFactory, ManualResetEvent waitHandle, ref Thread thread)
{
if (Interlocked.CompareExchange(ref _isValueCreated, 1, 0) == 0)
{
try
{
thread = Thread.CurrentThread;
GC.KeepAlive(thread);
_target = valueFactory.Invoke();
_valueFactory = FuncHelper.GetReturnFunc(_target);
return(_target);
}
catch (Exception exc)
{
_valueFactory = FuncHelper.GetThrowFunc <T>(exc);
throw;
}
finally
{
waitHandle.Set();
thread = null;
}
}
else
{
if (ReferenceEquals(thread, Thread.CurrentThread))
{
throw new InvalidOperationException();
}
waitHandle.WaitOne();
return(_valueFactory.Invoke());
}
}
private T CachingFullMode(Func <T> valueFactory, EventWaitHandle waitHandle, ref Thread thread)
{
if (Interlocked.CompareExchange(ref _isValueCreated, 1, 0) == 0)
{
try
{
thread = Thread.CurrentThread;
GC.KeepAlive(thread);
ValueForDebugDisplay = valueFactory.Invoke();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
return(ValueForDebugDisplay);
}
catch (Exception exc)
{
_valueFactory = FuncHelper.GetThrowFunc <T>(exc);
throw;
}
finally
{
waitHandle.Set();
thread = null;
}
}
if (thread == Thread.CurrentThread)
{
throw new InvalidOperationException();
}
waitHandle.WaitOne();
return(_valueFactory.Invoke());
}
private Lazy(Func <T> valueFactory, LazyThreadSafetyMode mode, bool cacheExceptions)
{
if (valueFactory == null)
{
throw new ArgumentNullException(nameof(valueFactory));
}
switch (mode)
{
case LazyThreadSafetyMode.None:
if (cacheExceptions)
{
var threads = new HashSet <Thread>();
_valueFactory =
() => CachingNoneMode(threads, valueFactory);
}
else
{
var threads = new HashSet <Thread>();
_valueFactory =
() => NoneMode(threads, valueFactory);
}
break;
case LazyThreadSafetyMode.PublicationOnly:
_valueFactory = PublicationOnlyMode;
break;
default: /*LazyThreadSafetyMode.ExecutionAndPublication*/
if (cacheExceptions)
{
Thread? thread = null;
ManualResetEvent?manualResetEvent = null;
_valueFactory =
() => CachingFullMode(valueFactory, ref manualResetEvent, ref thread);
}
else
{
Thread? thread = null;
ManualResetEvent?manualResetEvent = null;
_valueFactory =
() => FullMode(valueFactory, ref manualResetEvent, ref thread);
}
break;
}
T PublicationOnlyMode()
{
ValueForDebugDisplay = valueFactory();
if (Interlocked.CompareExchange(ref _isValueCreated, 1, 0) == 0)
{
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
}
return(ValueForDebugDisplay);
}
}
private T PublicationOnlyMode(Func <T> valueFactory)
{
_target = valueFactory();
if (Interlocked.CompareExchange(ref _isValueCreated, 1, 0) == 0)
{
_valueFactory = FuncHelper.GetReturnFunc(_target);
}
return(_target);
}
private T FullMode(Func <T> valueFactory, ref ManualResetEvent?waitHandle, ref Thread?thread)
{
if (waitHandle == null)
{
waitHandle = new ManualResetEvent(false);
}
while (Volatile.Read(ref _isValueCreated) != 1)
{
var foundThread = Interlocked.CompareExchange(ref thread, Thread.CurrentThread, null);
if (foundThread == null)
{
try
{
ValueForDebugDisplay = valueFactory.Invoke();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
Volatile.Write(ref _isValueCreated, 1);
return(ValueForDebugDisplay);
}
finally
{
Volatile.Write(ref thread, default);
waitHandle.Set();
if (Volatile.Read(ref _isValueCreated) == 1)
{
waitHandle.Close();
}
}
}
if (foundThread == Thread.CurrentThread)
{
throw new InvalidOperationException();
}
if (waitHandle.SafeWaitHandle.IsClosed)
{
continue;
}
try
{
waitHandle.WaitOne();
}
catch (ObjectDisposedException exception)
{
_ = exception;
}
}
return(_valueFactory.Invoke());
}
private T CachingFullMode(Func <T> valueFactory, ref ManualResetEvent?waitHandle, ref Thread?thread)
{
if (waitHandle == null)
{
waitHandle = new ManualResetEvent(false);
}
if (Interlocked.CompareExchange(ref _isValueCreated, 1, 0) == 0)
{
Volatile.Write(ref thread, Thread.CurrentThread);
try
{
ValueForDebugDisplay = valueFactory.Invoke();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
return(ValueForDebugDisplay);
}
catch (Exception exc)
{
_valueFactory = FuncHelper.GetThrowFunc <T>(exc);
throw;
}
finally
{
Volatile.Write(ref thread, null);
waitHandle.Set();
waitHandle.Close();
}
}
if (Volatile.Read(ref thread) == Thread.CurrentThread)
{
throw new InvalidOperationException();
}
if (waitHandle.SafeWaitHandle.IsClosed)
{
return(_valueFactory.Invoke());
}
try
{
waitHandle.WaitOne();
}
catch (ObjectDisposedException exception)
{
_ = exception;
}
return(_valueFactory.Invoke());
}
private T FullMode(Func <T> valueFactory, ManualResetEvent waitHandle, ref Thread thread, ref int preIsValueCreated)
{
back:
if (Interlocked.CompareExchange(ref preIsValueCreated, 1, 0) == 0)
{
try
{
thread = Thread.CurrentThread;
GC.KeepAlive(thread);
_target = valueFactory.Invoke();
_valueFactory = FuncHelper.GetReturnFunc(_target);
Thread.VolatileWrite(ref _isValueCreated, 1);
return(_target);
}
catch (Exception)
{
Thread.VolatileWrite(ref preIsValueCreated, 0);
throw;
}
finally
{
waitHandle.Set();
thread = null;
}
}
else
{
if (ReferenceEquals(thread, Thread.CurrentThread))
{
throw new InvalidOperationException();
}
else
{
waitHandle.WaitOne();
if (Thread.VolatileRead(ref _isValueCreated) == 1)
{
return(_valueFactory.Invoke());
}
else
{
goto back;
}
}
}
}
private T NoneMode(Func <T> valueFactory, HashSet <Thread> threads)
{
// NOTICE this method has no null check
var currentThread = Thread.CurrentThread;
if (Thread.VolatileRead(ref _isValueCreated) == 0)
{
try
{
// lock (threads) // This is meant to not be thread-safe
{
if (threads.Contains(currentThread))
{
throw new InvalidOperationException();
}
else
{
threads.Add(currentThread);
}
}
_target = valueFactory();
_valueFactory = FuncHelper.GetReturnFunc(_target);
Thread.VolatileWrite(ref _isValueCreated, 1);
return(_target);
}
catch (Exception)
{
Thread.VolatileWrite(ref _isValueCreated, 0);
throw;
}
finally
{
// lock (threads) // This is meant to not be thread-safe
{
threads.Remove(Thread.CurrentThread);
}
}
}
else
{
return(_valueFactory.Invoke());
}
}
private T FullMode(Func <T> valueFactory, EventWaitHandle waitHandle, ref Thread thread, ref int preIsValueCreated)
{
back:
if (Interlocked.CompareExchange(ref preIsValueCreated, 1, 0) == 0)
{
try
{
thread = Thread.CurrentThread;
GC.KeepAlive(thread);
ValueForDebugDisplay = valueFactory.Invoke();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
Volatile.Write(ref _isValueCreated, 1);
return(ValueForDebugDisplay);
}
catch (Exception)
{
Volatile.Write(ref preIsValueCreated, 0);
throw;
}
finally
{
waitHandle.Set();
thread = null;
}
}
if (thread == Thread.CurrentThread)
{
throw new InvalidOperationException();
}
waitHandle.WaitOne();
if (Volatile.Read(ref _isValueCreated) == 1)
{
return(_valueFactory.Invoke());
}
goto back;
}
private Lazy(Func <T> valueFactory, LazyThreadSafetyMode mode, bool cacheExceptions)
{
if (valueFactory == null)
{
throw new ArgumentNullException(nameof(valueFactory));
}
switch (mode)
{
case LazyThreadSafetyMode.None:
{
if (cacheExceptions)
{
var threads = new HashSet <Thread>();
_valueFactory =
() => CachingNoneMode(threads);
}
else
{
var threads = new HashSet <Thread>();
_valueFactory =
() => NoneMode(threads);
}
}
break;
case LazyThreadSafetyMode.PublicationOnly:
{
_valueFactory = PublicationOnlyMode;
}
break;
default: /*LazyThreadSafetyMode.ExecutionAndPublication*/
{
if (cacheExceptions)
{
Thread? thread = null;
ManualResetEvent?manualResetEvent = null;
_valueFactory =
() => CachingFullMode(valueFactory, ref manualResetEvent, ref thread);
}
else
{
Thread? thread = null;
ManualResetEvent?manualResetEvent = null;
_valueFactory =
() => FullMode(valueFactory, ref manualResetEvent, ref thread);
}
}
break;
}
T CachingNoneMode(HashSet <Thread> threads)
{
if (Volatile.Read(ref _isValueCreated) != 0)
{
return(_valueFactory.Invoke());
}
try
{
// lock (threads) // This is meant to not be thread-safe
{
var currentThread = Thread.CurrentThread;
if (threads.Contains(currentThread))
{
throw new InvalidOperationException();
}
threads.Add(currentThread);
}
ValueForDebugDisplay = valueFactory();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
Volatile.Write(ref _isValueCreated, 1);
return(ValueForDebugDisplay);
}
catch (Exception exception)
{
_valueFactory = FuncHelper.GetThrowFunc <T>(exception);
throw;
}
finally
{
// lock (threads) // This is meant to not be thread-safe
{
threads.Remove(Thread.CurrentThread);
}
}
}
T NoneMode(HashSet <Thread> threads)
{
if (Volatile.Read(ref _isValueCreated) != 0)
{
return(_valueFactory.Invoke());
}
try
{
// lock (threads) // This is meant to not be thread-safe
{
var currentThread = Thread.CurrentThread;
if (threads.Contains(currentThread))
{
throw new InvalidOperationException();
}
threads.Add(currentThread);
}
ValueForDebugDisplay = valueFactory();
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
Volatile.Write(ref _isValueCreated, 1);
return(ValueForDebugDisplay);
}
catch (Exception)
{
Volatile.Write(ref _isValueCreated, 0);
throw;
}
finally
{
// lock (threads) // This is meant to not be thread-safe
{
threads.Remove(Thread.CurrentThread);
}
}
}
T PublicationOnlyMode()
{
ValueForDebugDisplay = valueFactory();
if (Interlocked.CompareExchange(ref _isValueCreated, 1, 0) == 0)
{
_valueFactory = FuncHelper.GetReturnFunc(ValueForDebugDisplay);
}
return(ValueForDebugDisplay);
}
}