valueiterator.h

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/* Copyright (C) 2008,2009,2010,2011,2012,2013,2014,2015 Olly Betts
 *
 * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301
 * USA
 */

#ifndef XAPIAN_INCLUDED_VALUEITERATOR_H
#define XAPIAN_INCLUDED_VALUEITERATOR_H

#if !defined XAPIAN_IN_XAPIAN_H && !defined XAPIAN_LIB_BUILD
# error Never use <xapian/valueiterator.h> directly; include <xapian.h> instead.
#endif

#include <iterator>
#include <string>

#include <xapian/attributes.h>
#include <xapian/derefwrapper.h>
#include <xapian/types.h>
#include <xapian/visibility.h>

namespace Xapian {

class XAPIAN_VISIBILITY_DEFAULT ValueIterator {
    void decref();

  public:
    class Internal;
    Internal * internal;

    explicit ValueIterator(Internal *internal_);

    ValueIterator(const ValueIterator & o);

    ValueIterator & operator=(const ValueIterator & o);

#ifdef XAPIAN_MOVE_SEMANTICS
    ValueIterator(ValueIterator && o)
        : internal(o.internal) {
        o.internal = nullptr;
    }

    ValueIterator & operator=(ValueIterator && o) {
        if (this != &o) {
            if (internal) decref();
            internal = o.internal;
            o.internal = nullptr;
        }
        return *this;
    }
#endif

    XAPIAN_NOTHROW(ValueIterator())
        : internal() { }

    ~ValueIterator() {
        if (internal) decref();
    }

    std::string operator*() const;

    ValueIterator & operator++();

    DerefWrapper_<std::string> operator++(int) {
        const std::string & value(**this);
        operator++();
        return DerefWrapper_<std::string>(value);
    }

    Xapian::docid get_docid() const;

    Xapian::valueno get_valueno() const;

    void skip_to(Xapian::docid docid_or_slot);

#ifndef check
    bool check(Xapian::docid docid);
#else
    // The AssertMacros.h header in the macOS SDK currently defines a check
    // macro.  Apple have deprecated check() in favour of __Check() and
    // plan to remove check() in a "future release", but for now prevent
    // expansion of check by adding parentheses in the method prototype:
    // https://www.opensource.apple.com/source/CarbonHeaders/CarbonHeaders-18.1/AssertMacros.h
    //
    // We do this conditionally, as these parentheses trip up SWIG's
    // parser:
    // https://github.com/swig/swig/issues/45
    bool (check)(Xapian::docid docid);
#endif

    std::string get_description() const;

    // @{
    typedef std::input_iterator_tag iterator_category;
    typedef std::string value_type;
    typedef Xapian::doccount_diff difference_type;
    typedef std::string * pointer;
    typedef std::string & reference;
    // @}
};

bool
XAPIAN_NOTHROW(operator==(const ValueIterator &a, const ValueIterator &b));

inline bool
operator==(const ValueIterator &a, const ValueIterator &b) XAPIAN_NOEXCEPT
{
    // Use a pointer comparison - this ensures both that (a == a) and correct
    // handling of end iterators (which we ensure have NULL internals).
    return a.internal == b.internal;
}

bool
XAPIAN_NOTHROW(operator!=(const ValueIterator &a, const ValueIterator &b));

inline bool
operator!=(const ValueIterator &a, const ValueIterator &b) XAPIAN_NOEXCEPT
{
    return !(a == b);
}

}

#endif // XAPIAN_INCLUDED_VALUEITERATOR_H