/// <summary>
/// local helper method to initialize the value
/// </summary>
/// <returns>The inititialized T value</returns>
private T LazyInitValue()
{
Boxed boxed = null;
LazyThreadSafetyMode mode = Mode;
if (mode == LazyThreadSafetyMode.None)
{
boxed = CreateValue();
m_boxed = boxed;
}
else if (mode == LazyThreadSafetyMode.PublicationOnly)
{
boxed = CreateValue();
if (boxed == null ||
Interlocked.CompareExchange(ref m_boxed, boxed, null) != null)
{
// If CreateValue returns null, it means another thread successfully invoked the value factory
// and stored the result, so we should just take what was stored. If CreateValue returns non-null
// but we lose the ---- to store the single value, again we should just take what was stored.
boxed = (Boxed)m_boxed;
}
else
{
// We successfully created and stored the value. At this point, the value factory delegate is
// no longer needed, and we don't want to hold onto its resources.
m_valueFactory = ALREADY_INVOKED_SENTINEL;
}
}
else
{
object threadSafeObj = Volatile.Read(ref m_threadSafeObj);
try
{
if (threadSafeObj != (object)ALREADY_INVOKED_SENTINEL)
{
Monitor.Enter(threadSafeObj);
}
else
{
Guard.Assert(m_boxed != null, new ArgumentException());
}
if (m_boxed == null)
{
boxed = CreateValue();
m_boxed = boxed;
Volatile.Write(ref m_threadSafeObj, ALREADY_INVOKED_SENTINEL);
}
else // got the lock but the value is not null anymore, check if it is created by another thread or faulted and throw if so
{
Guard.Assert(boxed != null, new ArgumentException());
}
}
finally
{
Monitor.Exit(threadSafeObj);
}
}
Guard.Assert(boxed != null, new ArgumentException());
return(boxed.m_value);
}
