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[thirdparty/squid.git] / src / adaptation / icap / Launcher.h

/*
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  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,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#ifndef SQUID_ICAPLAUNCHER_H
#define SQUID_ICAPLAUNCHER_H

#include "adaptation/icap/ServiceRep.h"
#include "adaptation/Initiate.h"
#include "adaptation/Initiator.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.
 */

namespace Adaptation
{
namespace Icap
{

class Xaction;
class XactAbortInfo;

// Note: Initiate must be the first parent for cbdata to work. We use
// a temporary InitaitorHolder/toCbdata hacks and do not call cbdata
// operations on the initiator directly.
class Launcher: public Adaptation::Initiate, public Adaptation::Initiator
{
public:
    Launcher(const char *aTypeName, Adaptation::ServicePointer &aService);
    virtual ~Launcher();

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

    // Adaptation::Initiator: asynchronous communication with the current transaction
    virtual void noteAdaptationAnswer(const Answer &answer);
    virtual void noteXactAbort(XactAbortInfo info);

private:
    bool canRetry(XactAbortInfo &info) const; //< true if can retry in the case of persistent connection failures
    bool canRepeat(XactAbortInfo &info) const; //< true if can repeat in the case of no or unsatisfactory response

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

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

    void launchXaction(const char *xkind);

    Adaptation::ServicePointer theService; ///< ICAP service for all launches
    CbcPointer<Initiate> theXaction; ///< current ICAP transaction
    int theLaunches; // the number of transaction launches
};

/// helper class to pass information about aborted ICAP requests to
/// the Adaptation::Icap::Launcher class
class XactAbortInfo
{
public:
    XactAbortInfo(HttpRequest *anIcapRequest, HttpReply *anIcapReply,
                  bool beRetriable, bool beRepeatable);
    XactAbortInfo(const XactAbortInfo &);
    ~XactAbortInfo();

    std::ostream &print(std::ostream &os) const {
        return os << isRetriable << ',' << isRepeatable;
    }

    HttpRequest *icapRequest;
    HttpReply *icapReply;
    bool isRetriable;
    bool isRepeatable;

private:
    XactAbortInfo &operator =(const XactAbortInfo &); // undefined
};

inline
std::ostream &
operator <<(std::ostream &os, const XactAbortInfo &xai)
{
    return xai.print(os);
}

} // namespace Icap
} // namespace Adaptation

#endif /* SQUID_ICAPLAUNCHER_H */