/// <devdoc>
/// <para>
/// Used by the ServicePoint to find a free or new Connection
/// for use in making Requests.
/// </para>
/// </devdoc>
public Connection FindConnection(string connName)
{
Connection leastbusyConnection = null;
Connection newConnection = null;
bool freeConnectionsAvail = false;
GlobalLog.Print("ConnectionGroup::FindConnection [" + connName + "] m_ConnectionList.Count:" + m_ConnectionList.Count.ToString());
lock (m_ConnectionList) {
//
// go through the list of open connections to this service point and pick
// the first empty one or, if none is empty, pick the least busy one.
//
bool completed;
do
{
int minBusyCount = Int32.MaxValue;
completed = true; // by default, only once through the outer loop
foreach (WeakReference currentConnectionReference in m_ConnectionList)
{
Connection currentConnection = null;
if (currentConnectionReference != null)
{
currentConnection = currentConnectionReference.Target as Connection;
}
//
// If the weak reference is alive, see if its not busy,
// otherwise make sure to remove it from the list
//
if (currentConnection != null)
{
GlobalLog.Print("ConnectionGroup::FindConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString());
if (currentConnection.BusyCount < minBusyCount)
{
leastbusyConnection = currentConnection;
minBusyCount = currentConnection.BusyCount;
if (minBusyCount == 0)
{
freeConnectionsAvail = true;
break;
}
}
}
else
{
m_ConnectionList.Remove(currentConnectionReference);
completed = false;
// now start iterating again because we changed the ArrayList
break;
}
}
} while (!completed);
//
// If there is NOT a Connection free, then we allocate a new Connection
//
if (!freeConnectionsAvail && CurrentConnections < InternalConnectionLimit)
{
//
// If we can create a new connection, then do it,
// this may have complications in pipeling because
// we may wish to optimize this case by actually
// using existing connections, rather than creating new ones
//
// Note: this implicately results in a this.Associate being called.
//
GlobalLog.Print("ConnectionGroup::FindConnection [returning new Connection] freeConnectionsAvail:" + freeConnectionsAvail.ToString() + " CurrentConnections:" + CurrentConnections.ToString() + " InternalConnectionLimit:" + InternalConnectionLimit.ToString());
newConnection =
new Connection(
this,
m_ServicePoint,
m_IPAddress,
m_ServicePoint.ProtocolVersion,
m_ServicePoint.SupportsPipelining);
}
else
{
//
// All connections are busy, use the least busy one
//
GlobalLog.Print("ConnectionGroup::FindConnection [returning leastbusyConnection] freeConnectionsAvail:" + freeConnectionsAvail.ToString() + " CurrentConnections:" + CurrentConnections.ToString() + " InternalConnectionLimit:" + InternalConnectionLimit.ToString());
GlobalLog.Assert(leastbusyConnection != null, "Connect.leastbusyConnection != null", "All connections have BusyCount equal to Int32.MaxValue");
newConnection = leastbusyConnection;
}
}
return(newConnection);
}
/// <devdoc>
/// <para>
/// Attempts to match a request with a connection, if a connection is unassigned ie not locked with
/// a request, then the least busy connections is returned in "leastbusyConnection." If the
/// connection limit allows, and all connections are busy, a new one is allocated and returned.
///
/// RETURNS: a Connection shown to match a previously locked Request/Connection (OTHERWISE)
/// leasebusyConnection - will contain a newly allocated Connection or least Busy one
/// suiteable for requests.
///
/// NOTE: For Whidbey: try to integrate this code into FindConnection()
/// </para>
/// </devdoc>
private Connection FindMatchingConnection(HttpWebRequest request, string connName, out Connection leastbusyConnection)
{
int minBusyCount = Int32.MaxValue;
bool freeConnectionsAvail = false;
leastbusyConnection = null;
lock (m_ConnectionList) {
//
// go through the list of open connections to this service point and pick
// the first empty one or, if none is empty, pick the least busy one.
//
bool completed;
do
{
minBusyCount = Int32.MaxValue;
completed = true; // by default, only once through the outer loop
foreach (WeakReference currentConnectionReference in m_ConnectionList)
{
Connection currentConnection = null;
if (currentConnectionReference != null)
{
currentConnection = currentConnectionReference.Target as Connection;
}
//
// If the weak reference is alive, see if its not busy,
// otherwise make sure to remove it from the list
//
if (currentConnection != null)
{
GlobalLog.Print("ConnectionGroup::FindConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString());
if (currentConnection.LockedRequest == request)
{
leastbusyConnection = currentConnection;
return(currentConnection);
}
GlobalLog.Print("ConnectionGroup::FindConnection: lockedRequest# " + ((currentConnection.LockedRequest == null) ? "null" : currentConnection.LockedRequest.GetHashCode().ToString()));
if (currentConnection.BusyCount < minBusyCount && currentConnection.LockedRequest == null)
{
leastbusyConnection = currentConnection;
minBusyCount = currentConnection.BusyCount;
if (minBusyCount == 0)
{
freeConnectionsAvail = true;
}
}
}
else
{
m_ConnectionList.Remove(currentConnectionReference);
completed = false;
// now start iterating again because we changed the ArrayList
break;
}
}
} while (!completed);
//
// If there is NOT a Connection free, then we allocate a new Connection
//
if (!freeConnectionsAvail && CurrentConnections < InternalConnectionLimit)
{
//
// If we can create a new connection, then do it,
// this may have complications in pipeling because
// we may wish to optimize this case by actually
// using existing connections, rather than creating new ones
//
// Note: this implicately results in a this.Associate being called.
//
GlobalLog.Print("ConnectionGroup::FindConnection [returning new Connection] CurrentConnections:" + CurrentConnections.ToString() + " InternalConnectionLimit:" + InternalConnectionLimit.ToString());
leastbusyConnection =
new Connection(
this,
m_ServicePoint,
m_IPAddress,
m_ServicePoint.ProtocolVersion,
m_ServicePoint.SupportsPipelining
);
}
}
return(null); // only if we have a locked Connection that matches can return non-null
}
