protected override sealed Delegate CombineImpl(Delegate other)
{
if (other == null)
{
return(this);
}
MulticastDelegate o = (MulticastDelegate)other;
var oInvList = o.InvocationList;
var oInvLen = o.InvocationListLength;
o = o.WithoutInvocationList(); // we flatten the list.
var newInvList = InvocationList;
var curInvLen = InvocationListLength;
int newInvLen = curInvLen + 1 + oInvLen;
bool needNewList = newInvList == null || newInvList.Length < newInvLen;
// try appending to the current list.
if (!needNewList)
{
//if (Interlocked.CompareExchange(ref lostInvocationList, 1, 0) != 0 /*!TakeInvokationListOwnership()*/)
// The locking might acually be faster than forcing a field of the class to be volatile,
// but more measurements are needed.
lock (InvocationList)
{
if (lostInvocationList != 0)
{
needNewList = true;
}
else
{
lostInvocationList = 1;
}
}
if (!needNewList)
{
newInvList[curInvLen] = o;
for (int i = 0; i < oInvLen; ++i)
{
newInvList[curInvLen + i + 1] = oInvList[i];
}
}
}
if (needNewList)
{
// start by 4, duplicate size.
int len = newInvList == null ? 4 : newInvList.Length;
while (len < newInvLen)
{
len *= 2;
}
MulticastDelegate[] list = new MulticastDelegate[len];
var curInvList = InvocationList;
for (int i = 0; i < curInvLen; ++i)
{
list[i] = curInvList[i];
}
list[curInvLen] = o;
for (int i = 0; i < oInvLen; ++i)
{
list[curInvLen + 1 + i] = oInvList[i];
}
newInvList = list;
}
return(this.CloneWithNewInvocationList(newInvList, newInvLen));
}