/// <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 free one or,
// if none is free, pick the least busy one. Skip all connections with non keep-alive request pipelined.
//
minBusyCount = Int32.MaxValue;
foreach (Connection currentConnection in m_ConnectionList)
{
GlobalLog.Print("ConnectionGroup::FindMatchingConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString());
if (currentConnection.LockedRequest == request)
{
leastbusyConnection = currentConnection;
return(currentConnection);
}
GlobalLog.Print("ConnectionGroup::FindMatchingConnection: lockedRequest# " + ((currentConnection.LockedRequest == null) ? "null" : currentConnection.LockedRequest.GetHashCode().ToString()));
if (!currentConnection.NonKeepAliveRequestPipelined && currentConnection.BusyCount < minBusyCount && currentConnection.LockedRequest == null)
{
leastbusyConnection = currentConnection;
minBusyCount = currentConnection.BusyCount;
if (minBusyCount == 0)
{
freeConnectionsAvail = true;
}
}
}
//
// If there is NOT a Connection free, then we allocate a new Connection
//
if (!freeConnectionsAvail && CurrentConnections < ConnectionLimit)
{
//
// 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::FindMatchingConnection [returning new Connection] CurrentConnections:" + CurrentConnections.ToString() + " ConnectionLimit:" + ConnectionLimit.ToString());
leastbusyConnection = new Connection(this);
}
}
return(null); // only if we have a locked Connection that matches can return non-null
}
/// <devdoc>
/// <para>
/// Used by the ServicePoint to find a free or new Connection
/// for use in making Requests. Under NTLM and Negotiate requests,
/// this function depricates itself and switches the object over to
/// using a new code path (see FindConnectionAuthenticationGroup).
/// </para>
/// </devdoc>
internal Connection FindConnection(HttpWebRequest request, string connName, out bool forcedsubmit)
{
Connection leastbusyConnection = null;
Connection newConnection = null;
bool freeConnectionsAvail = false;
forcedsubmit = false;
if (m_AuthenticationGroup || request.LockConnection)
{
m_AuthenticationGroup = true;
return(FindConnectionAuthenticationGroup(request, connName));
}
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 connection as follows:
// - free connection
// - if there is no free connection and if we are under connection limit, create new connection
// - pick the least busy connection which does not have non-keep alive request pipelined
// - pick the least busy connection which may have non-keep alive request pipelined
// If we pick the connection with non keep-alive request pipelined on it, we set forcedsubmit to true.
// This will make sure that we don't start the request immediately and it gets queued on the connection.
//
int minBusyCount = Int32.MaxValue;
bool foundLiveConnection = false;
foreach (Connection currentConnection in m_ConnectionList)
{
GlobalLog.Print("ConnectionGroup::FindConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString());
bool useThisConnection = false;
if (foundLiveConnection)
{
useThisConnection = (!currentConnection.NonKeepAliveRequestPipelined && minBusyCount > currentConnection.BusyCount);
}
else
{
useThisConnection = (!currentConnection.NonKeepAliveRequestPipelined || minBusyCount > currentConnection.BusyCount);
}
if (useThisConnection)
{
leastbusyConnection = currentConnection;
minBusyCount = currentConnection.BusyCount;
if (!foundLiveConnection)
{
foundLiveConnection = !currentConnection.NonKeepAliveRequestPipelined;
}
else
{
GlobalLog.Assert(!currentConnection.NonKeepAliveRequestPipelined, "Connection.NonKeepAliveRequestPipelined == false|Non keep-alive request has been pipelined on this connection.");
}
if (foundLiveConnection && minBusyCount == 0)
{
freeConnectionsAvail = true;
break;
}
}
}
//
// If there is NOT a Connection free, then we allocate a new Connection
//
if (!freeConnectionsAvail && CurrentConnections < ConnectionLimit)
{
//
// 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() + " ConnectionLimit:" + ConnectionLimit.ToString());
newConnection = new Connection(this);
forcedsubmit = false;
}
else
{
//
// All connections are busy, use the least busy one
//
GlobalLog.Print("ConnectionGroup::FindConnection [returning leastbusyConnection] freeConnectionsAvail:" + freeConnectionsAvail.ToString() + " CurrentConnections:" + CurrentConnections.ToString() + " ConnectionLimit:" + ConnectionLimit.ToString());
GlobalLog.Assert(leastbusyConnection != null, "Connect.leastbusyConnection != null|All connections have BusyCount equal to Int32.MaxValue.");
newConnection = leastbusyConnection;
forcedsubmit = !foundLiveConnection;
}
newConnection.MarkAsReserved();
}
return(newConnection);
}
/// <devdoc>
/// <para>
/// Used by the ServicePoint to find a free or new Connection
/// for use in making Requests. Under NTLM and Negotiate requests,
/// this function depricates itself and switches the object over to
/// using a new code path (see FindConnectionAuthenticationGroup).
/// </para>
/// </devdoc>
internal Connection FindConnection(HttpWebRequest request, string connName)
{
Connection leastbusyConnection = null;
Connection newConnection = null;
bool freeConnectionsAvail = false;
if (m_AuthenticationGroup || request.LockConnection)
{
m_AuthenticationGroup = true;
return(FindConnectionAuthenticationGroup(request, connName));
}
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.
//
int minBusyCount = Int32.MaxValue;
foreach (Connection currentConnection in m_ConnectionList)
{
GlobalLog.Print("ConnectionGroup::FindConnection currentConnection.BusyCount:" + currentConnection.BusyCount.ToString());
if (currentConnection.BusyCount < minBusyCount)
{
leastbusyConnection = currentConnection;
minBusyCount = currentConnection.BusyCount;
if (minBusyCount == 0)
{
freeConnectionsAvail = true;
break;
}
}
}
//
// If there is NOT a Connection free, then we allocate a new Connection
//
if (!freeConnectionsAvail && CurrentConnections < ConnectionLimit)
{
//
// 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() + " ConnectionLimit:" + ConnectionLimit.ToString());
newConnection = new Connection(this);
}
else
{
//
// All connections are busy, use the least busy one
//
GlobalLog.Print("ConnectionGroup::FindConnection [returning leastbusyConnection] freeConnectionsAvail:" + freeConnectionsAvail.ToString() + " CurrentConnections:" + CurrentConnections.ToString() + " ConnectionLimit:" + ConnectionLimit.ToString());
GlobalLog.Assert(leastbusyConnection != null, "Connect.leastbusyConnection != null|All connections have BusyCount equal to Int32.MaxValue.");
newConnection = leastbusyConnection;
}
}
return(newConnection);
}
