mu/lib/mu-xapian.cc

119 lines
3.8 KiB
C++

/*
** Copyright (C) 2017 Dirk-Jan C. Binnema <djcb@djcbsoftware.nl>
**
** This library is free software; you can redistribute it and/or
** modify it under the terms of the GNU Lesser General Public License
** as published by the Free Software Foundation; either version 2.1
** of the License, or (at your option) any later version.
**
** This library 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
** Lesser General Public License for more details.
**
** You should have received a copy of the GNU Lesser General Public
** License along with this library; if not, write to the Free
** Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
** 02110-1301, USA.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif /*HAVE_CONFIG_H*/
#include <xapian.h>
#include "mu-xapian.hh"
#include <utils/mu-error.hh>
using namespace Mu;
static Xapian::Query
xapian_query_op(const Mu::Tree& tree)
{
Xapian::Query::op op;
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wswitch-enum"
switch (tree.node.type) {
case Node::Type::OpNot: // OpNot x ::= <all> AND NOT x
if (tree.children.size() != 1)
throw std::runtime_error("invalid # of children");
return Xapian::Query(Xapian::Query::OP_AND_NOT,
Xapian::Query::MatchAll,
xapian_query(tree.children.front()));
case Node::Type::OpAnd: op = Xapian::Query::OP_AND; break;
case Node::Type::OpOr: op = Xapian::Query::OP_OR; break;
case Node::Type::OpXor: op = Xapian::Query::OP_XOR; break;
case Node::Type::OpAndNot: op = Xapian::Query::OP_AND_NOT; break;
default: throw Mu::Error(Error::Code::Internal, "invalid op"); // bug
}
#pragma GCC diagnostic pop
std::vector<Xapian::Query> childvec;
for (const auto& subtree : tree.children)
childvec.emplace_back(xapian_query(subtree));
return Xapian::Query(op, childvec.begin(), childvec.end());
}
static Xapian::Query
make_query(const Value* val, const std::string& str, bool maybe_wildcard)
{
const auto vlen{str.length()};
if (!maybe_wildcard || vlen <= 1 || str[vlen - 1] != '*')
return Xapian::Query(val->prefix + str);
else
return Xapian::Query(Xapian::Query::OP_WILDCARD,
val->prefix + str.substr(0, vlen - 1));
}
static Xapian::Query
xapian_query_value(const Mu::Tree& tree)
{
const auto v = dynamic_cast<Value*>(tree.node.data.get());
if (!v->phrase)
return make_query(v, v->value, true /*maybe-wildcard*/);
const auto parts = split(v->value, " ");
if (parts.empty())
return Xapian::Query::MatchNothing; // shouldn't happen
if (parts.size() == 1)
return make_query(v, parts.front(), true /*maybe-wildcard*/);
std::vector<Xapian::Query> phvec;
for (const auto& p : parts)
phvec.emplace_back(make_query(v, p, false /*no wildcards*/));
return Xapian::Query(Xapian::Query::OP_PHRASE, phvec.begin(), phvec.end());
}
static Xapian::Query
xapian_query_range(const Mu::Tree& tree)
{
const auto r{dynamic_cast<Range*>(tree.node.data.get())};
return Xapian::Query(Xapian::Query::OP_VALUE_RANGE,
(Xapian::valueno)r->id,
r->lower,
r->upper);
}
Xapian::Query
Mu::xapian_query(const Mu::Tree& tree)
{
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wswitch-enum"
switch (tree.node.type) {
case Node::Type::Empty: return Xapian::Query();
case Node::Type::OpNot:
case Node::Type::OpAnd:
case Node::Type::OpOr:
case Node::Type::OpXor:
case Node::Type::OpAndNot: return xapian_query_op(tree);
case Node::Type::Value: return xapian_query_value(tree);
case Node::Type::Range: return xapian_query_range(tree);
default: throw Mu::Error(Error::Code::Internal, "invalid query"); // bug
}
#pragma GCC diagnostic pop
}