/* query-fp.cc - "query:" field processor glue
 *
 * This file is part of notmuch.
 *
 * Copyright © 2015 Austin Clements
 * Copyright © 2016 David Bremner
 *
 * 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 3 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, see https://www.gnu.org/licenses/ .
 *
 * Author: Austin Clements <aclements@csail.mit.edu>
 *                David Bremner <david@tethera.net>
 */

#include "regexp-fields.h"

#ifdef HAVE_XAPIAN_FIELD_PROCESSOR
RegexpPostingSource::RegexpPostingSource (Xapian::valueno slot, const std::string &regexp)
    : slot_ (slot)
{
    int r = regcomp (&regexp_, regexp.c_str (), REG_EXTENDED | REG_NOSUB);

    if (r != 0)
	/* XXX Report a query syntax error using regerror */
	throw "regcomp failed";
}

RegexpPostingSource::~RegexpPostingSource ()
{
    regfree (&regexp_);
}

void
RegexpPostingSource::init (const Xapian::Database &db)
{
    db_ = db;
    it_ = db_.valuestream_begin (slot_);
    end_ = db.valuestream_end (slot_);
    started_ = false;
}

Xapian::doccount
RegexpPostingSource::get_termfreq_min () const
{
    return 0;
}

Xapian::doccount
RegexpPostingSource::get_termfreq_est () const
{
    return get_termfreq_max () / 2;
}

Xapian::doccount
RegexpPostingSource::get_termfreq_max () const
{
    return db_.get_value_freq (slot_);
}

Xapian::docid
RegexpPostingSource::get_docid () const
{
    return it_.get_docid ();
}

bool
RegexpPostingSource::at_end () const
{
    return it_ == end_;
}

void
RegexpPostingSource::next (unused (double min_wt))
{
    if (started_ && ! at_end ())
	++it_;
    started_ = true;

    for (; ! at_end (); ++it_) {
	std::string value = *it_;
	if (regexec (&regexp_, value.c_str (), 0, NULL, 0) == 0)
	    break;
    }
}

Xapian::Query
RegexpFieldProcessor::operator() (const std::string & str)
{
    postings = new RegexpPostingSource (slot, str);
    return Xapian::Query (postings);
}
#endif