Simplify appending SBuf to String (#2108)

[thirdparty/squid.git] / src / ConfigOption.h

/*
 * Copyright (C) 1996-2025 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_SRC_CONFIGOPTION_H
#define SQUID_SRC_CONFIGOPTION_H

#include <iosfwd>
#include <vector>

class StoreEntry;
class ConfigParser;

namespace Configuration {

/// Interface for basic/low-level manipulation of a squid.conf directive value.
/// Hides T's declarations from squid.conf parsing/reconfiguring/reporting code.
///
/// Implementations/specializations must not modify the current configuration
/// (i.e. the Config objects and similar/related global state). To facilitate
/// reuse, implementations/specializations should also be independent from any
/// specific configuration directive name and its squid.conf location.
///
/// TODO: Support multi-directive components of various kinds.
template <class T>
class Component
{
public:
    /* the code adding "TYPE: T" to cf.data.pre must specialize these */

    /// creates a new T instance using the given parser; never returns nil
    static T Parse(ConfigParser &);

    /// reports the current T instance configuration in squid.conf format
    static void Print(std::ostream &, const T &);

    /// destroys Parse() result
    static void Free(T);
};

} // namespace Configuration

/*
 * Deprecated squid.conf option wrappers used by cache_dir handling code. These
 * classes are similar to Configuration::Component<T>, but they merge T with T
 * parsing API, making them ill-suited for handling SquidConfig data members
 * with built-in C++ types and, more importantly, forcing SquidConfig users to
 * know about parsing/dumping/freeing capabilities of each SquidConfig
 * component. They also do not hide T details from the generic squid.conf
 * parsing code -- one has to provide a type-specific parse_T() for each T.
 */

class ConfigOption
{

public:
    virtual ~ConfigOption() {}

    virtual bool parse(char const *option, const char *value, int reconfiguring) = 0;
    virtual void dump(StoreEntry * e) const = 0;
};

class ConfigOptionVector : public ConfigOption
{

public:
    ~ConfigOptionVector() override;
    bool parse(char const *option, const char *value, int reconfiguring) override;
    void dump(StoreEntry * e) const override;
    std::vector<ConfigOption *>options;
};

template <class C>
class ConfigOptionAdapter : public ConfigOption
{

public:
    ConfigOptionAdapter(C& theObject, bool (C::*parseFP)(char const *option, const char *value, int reconfiguring), void (C::*dumpFP)(StoreEntry * e) const) : object(theObject), parser(parseFP), dumper(dumpFP) {}

    bool parse(char const *option, const char *value, int isaReconf) override {
        if (parser)
            return (object.*parser)(option, value, isaReconf);

        return false;
    }

    void dump(StoreEntry * e) const override {
        if (dumper)
            (object.*dumper)(e);
    }

private:
    C &object;
    bool (C::*parser)(char const *option, const char *value, int reconfiguring) ;
    void (C::*dumper)(StoreEntry * e) const;
};

#endif /* SQUID_SRC_CONFIGOPTION_H */