ServiceGroups.h

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/*
 * Copyright (C) 1996-2019 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */

#ifndef SQUID_ADAPTATION__SERVICE_GROUPS_H
#define SQUID_ADAPTATION__SERVICE_GROUPS_H

#include "adaptation/Elements.h"
#include "adaptation/forward.h"
#include "base/RefCount.h"
#include "SquidString.h"

#include <vector>

namespace Adaptation
{

// Interface for grouping adaptation services together.
// Specific groups differ in how the first and the next services are selected
class ServiceGroup: public RefCountable
{
public:
    typedef RefCount<ServiceGroup> Pointer;

    typedef std::vector<String> Store;
    typedef String Id;
    typedef unsigned int Pos; // vector<>::position_type
    friend class ServicePlan;

public:
    ServiceGroup(const String &aKind, bool areAllServicesSame);
    virtual ~ServiceGroup();

    virtual void parse();
    virtual void finalize(); // called after all are parsed

    bool wants(const ServiceFilter &filter) const;

protected:
    bool has(const Pos pos) const {
        // does not check that the service at pos still exists
        return pos < services.size(); // unsigned pos is never negative
    }


    bool findReplacement(const ServiceFilter &filter, Pos &pos) const;
    bool findLink(const ServiceFilter &filter, Pos &pos) const;

private:
    ServicePointer at(const Pos pos) const;
    bool findService(const ServiceFilter &filter, Pos &pos) const;

    void checkUniqueness(const Pos checkedPos) const;
    void finalizeMsg(const char *msg, const String &culprit, bool error) const;

public:
    String kind;
    Id id;
    Store services;
    Store removedServices;

    Method method; 
    VectPoint point; 

    const bool allServicesSame; // whether we can freely substitute services
};

// a group of equivalent services; one service per set is usually used
class ServiceSet: public ServiceGroup
{
public:
    ServiceSet();

protected:
    virtual bool replace(Pos &pos) const { return has(++pos); }
    virtual bool advance(Pos &) const { return false; }
};

// corner case: a group consisting of one service
class SingleService: public ServiceGroup
{
public:
    SingleService(const String &aServiceKey);

protected:
    virtual bool replace(Pos &) const { return false; }
    virtual bool advance(Pos &) const { return false; }
};

class ServiceChain: public ServiceGroup
{
public:
    ServiceChain();

protected:
    virtual bool replace(Pos &) const { return false; }
    virtual bool advance(Pos &pos) const { return has(++pos); }
};

class DynamicServiceChain: public ServiceChain
{
public:
    DynamicServiceChain(const DynamicGroupCfg &cfg, const ServiceFilter &f);

    static void Split(const ServiceFilter &filter, const String &ids,
                      DynamicGroupCfg &current, DynamicGroupCfg &future);
};

class ServicePlan
{
public:
    typedef unsigned int Pos; // vector<>::position_type

public:
    ServicePlan();
    explicit ServicePlan(const ServiceGroupPointer &g, const ServiceFilter &filter);

    bool exhausted() const { return atEof; }

    ServicePointer current() const; 
    ServicePointer replacement(const ServiceFilter &filter); 
    ServicePointer next(const ServiceFilter &filter); 

    std::ostream &print(std::ostream &os) const;

private:
    ServiceGroupPointer group; 
    Pos pos; 
    bool atEof; 
};

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

typedef std::vector<ServiceGroupPointer> Groups;
Groups &AllGroups();
ServiceGroupPointer FindGroup(const ServiceGroup::Id &id);

} // namespace Adaptation

#endif /* SQUID_ADAPTATION__SERVICE_GROUPS_H */