/* Copyright (C) 2012 J.F.Dockes
* 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.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef _SYNFAMILY_H_INCLUDED_
#define _SYNFAMILY_H_INCLUDED_
/**
* The Xapian synonyms mechanism can be used for many things beyond actual
* synonyms, anything that would turn a string into a group of equivalents.
* Unfortunately, it has only one keyspace.
* This class partitions the Xapian synonyms keyspace by using prefixes and
* can provide different applications each with a family of keyspaces.
* Two characters are reserved by the class and should not be used inside
* either family or member names: ':' and ';'
* A synonym key for family "stemdb", member "french", key "somestem"
* looks like:
* :stemdb:french:somestem -> somestem expansions
* A special entry is used to list all the members for a family, e.g.:
* :stemdb;members -> french, english ...
*/
#include <string>
#include <vector>
#include <xapian.h>
#include "debuglog.h"
#include "xmacros.h"
#include "strmatcher.h"
namespace Rcl {
class XapSynFamily {
public:
/**
* Construct from readable xapian database and family name (ie: Stm)
*/
XapSynFamily(Xapian::Database xdb, const std::string& familyname)
: m_rdb(xdb)
{
m_prefix1 = std::string(":") + familyname;
}
/** Retrieve all members of this family (e.g: french english german...) */
virtual bool getMembers(std::vector<std::string>&);
/** debug: list map for one member to stdout */
virtual bool listMap(const std::string& fam);
/** Expand term to list of synonyms for given member */
bool synExpand(const std::string& membername,
const std::string& term, std::vector<std::string>& result);
// The prefix shared by all synonym entries inside a family member
virtual std::string entryprefix(const std::string& member)
{
return m_prefix1 + ":" + member + ":";
}
// The key for the "list of members" entry
virtual std::string memberskey()
{
return m_prefix1 + ";" + "members";
}
Xapian::Database& getdb()
{
return m_rdb;
}
protected:
Xapian::Database m_rdb;
std::string m_prefix1;
};
/** Modify ops for a synonyms family
*
* A method to add a synonym entry inside a given member would make sense,
* but would not be used presently as all these ops go through
* ComputableSynFamMember objects
*/
class XapWritableSynFamily : public XapSynFamily {
public:
/** Construct with Xapian db open for r/w */
XapWritableSynFamily(Xapian::WritableDatabase db,
const std::string& familyname)
: XapSynFamily(db, familyname), m_wdb(db)
{
}
/** Delete all entries for one member (e.g. french), and remove from list
* of members */
virtual bool deleteMember(const std::string& membername);
/** Add to list of members. Idempotent, does not affect actual expansions */
virtual bool createMember(const std::string& membername);
Xapian::WritableDatabase getdb() {return m_wdb;}
protected:
Xapian::WritableDatabase m_wdb;
};
/** A functor which transforms a string */
class SynTermTrans {
public:
virtual std::string operator()(const std::string&) = 0;
};
/** A member (set of root-synonyms associations) of a SynFamily for
* which the root is computable from the input term.
* The objects use a functor member to compute the term root on input
* (e.g. compute the term sterm or casefold it
*/
class XapComputableSynFamMember {
public:
XapComputableSynFamMember(Xapian::Database xdb, std::string familyname,
std::string membername, SynTermTrans* trans)
: m_family(xdb, familyname), m_membername(membername),
m_trans(trans), m_prefix(m_family.entryprefix(m_membername))
{
}
/** Expand a term to its list of synonyms. If filtertrans is set we
* keep only the results which transform to the same value as the input
* This is used for example for filtering the result of case+diac
* expansion when only either case or diac expansion is desired.
*/
bool synExpand(const std::string& term, std::vector<std::string>& result,
SynTermTrans *filtertrans = 0);
/** Same with also wildcard/regexp expansion of entry against the keys.
* The input matcher will be modified to fit our key format. */
bool synKeyExpand(StrMatcher* in, std::vector<std::string>& result,
SynTermTrans *filtertrans = 0);
private:
XapSynFamily m_family;
std::string m_membername;
SynTermTrans *m_trans;
std::string m_prefix;
};
/** Computable term root SynFamily member, modify ops */
class XapWritableComputableSynFamMember {
public:
XapWritableComputableSynFamMember(
Xapian::WritableDatabase xdb, std::string familyname,
std::string membername, SynTermTrans* trans)
: m_family(xdb, familyname), m_membername(membername),
m_trans(trans), m_prefix(m_family.entryprefix(m_membername))
{
}
virtual bool addSynonym(const std::string& term)
{
LOGDEB2(("addSynonym:me %p term [%s] m_trans %p\n", this,
term.c_str(), m_trans));
std::string transformed = (*m_trans)(term);
LOGDEB2(("addSynonym: transformed [%s]\n", transformed.c_str()));
if (transformed == term)
return true;
std::string ermsg;
try {
m_family.getdb().add_synonym(m_prefix + transformed, term);
} XCATCHERROR(ermsg);
if (!ermsg.empty()) {
LOGERR(("XapWritableComputableSynFamMember::addSynonym: "
"xapian error %s\n", ermsg.c_str()));
return false;
}
return true;
}
void clear()
{
m_family.deleteMember(m_membername);
}
void recreate()
{
clear();
m_family.createMember(m_membername);
}
private:
XapWritableSynFamily m_family;
std::string m_membername;
SynTermTrans *m_trans;
std::string m_prefix;
};
//
// Prefixes are centrally defined here to avoid collisions
//
// Lowercase accented stem to expansion. Family member name: language
static const std::string synFamStem("Stm");
#ifndef RCL_INDEX_STRIPCHARS
// Lowercase unaccented stem to expansion. Family member name: language
static const std::string synFamStemUnac("StU");
// Lowercase unaccented term to case and accent variations. Only one
// member, named "all". This set is used for separate case/diac
// expansion by post-filtering the results of dual expansion.
static const std::string synFamDiCa("DCa");
#endif // !RCL_INDEX_STRIPCHARS
} // end namespace Rcl
#endif /* _SYNFAMILY_H_INCLUDED_ */