Bug #1819 fix in three parts: Retry failed ICAP pconns.

[thirdparty/squid.git] / src / ICAP / ICAPLauncher.h

/*
 * $Id: ICAPLauncher.h,v 1.1 2007/05/08 16:32:11 rousskov Exp $
 *
 *
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 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
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 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 */

#ifndef SQUID_ICAPLAUNCHER_H
#define SQUID_ICAPLAUNCHER_H

#include "ICAP/ICAPInitiator.h"
#include "ICAP/ICAPInitiate.h"

/*
 * The ICAP Launcher starts an ICAP transaction. If the transaction fails
 * due to what looks like a persistent connection race condition, the launcher
 * starts a new ICAP transaction using a freshly opened connection.
 *
 * ICAPLauncher and one or more ICAP transactions initiated by it form an
 * ICAP "query".
 *
 * An ICAP Initiator deals with the ICAP Launcher and not an individual ICAP
 * transaction because the latter may disappear and be replaced by another
 * transaction.
 *
 * Specific ICAP launchers implement the createXaction() method to create
 * REQMOD, RESPMOD, or OPTIONS transaction from initiator-supplied data.
 *
 * TODO: This class might be the right place to initiate ICAP ACL checks or 
 * implement more sophisticated ICAP transaction handling like chaining of 
 * ICAP transactions.
 */

class ICAPXaction;

// Note: ICAPInitiate must be the first parent for cbdata to work. We use
// a temporary ICAPInitaitorHolder/toCbdata hacks and do not call cbdata
// operations on the initiator directly.
class ICAPLauncher: public ICAPInitiate, public ICAPInitiator
{
public:
    ICAPLauncher(const char *aTypeName, ICAPInitiator *anInitiator, ICAPServiceRep::Pointer &aService);
    virtual ~ICAPLauncher();

    // ICAPInitiate: asynchronous communication with the initiator
    void noteInitiatorAborted();

    // ICAPInitiator: asynchronous communication with the current transaction
    virtual void noteIcapAnswer(HttpMsg *message);
    virtual void noteIcapQueryAbort(bool final);

    // a temporary cbdata-for-multiple inheritance hack, see ICAPInitiator.cc
    virtual void *toCbdata() { return this; }

protected:
    // ICAPInitiate API implementation
    virtual void start();
    virtual bool doneAll() const;
    virtual void swanSong();

    // creates the right ICAP transaction using stored configuration params
    virtual ICAPXaction *createXaction() = 0;

    void launchXaction(bool final);

    ICAPInitiate *theXaction; // current ICAP transaction
    int theLaunches; // the number of transaction launches
};

#endif /* SQUID_ICAPLAUNCHER_H */