#ifndef lint
static char rcsid[] = "@(#$Id: rcldb.cpp,v 1.65 2006-04-11 07:14:28 dockes Exp $ (C) 2004 J.F.Dockes";
#endif
/*
* 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.
*/
#include <stdio.h>
#include <unistd.h>
#include <sys/stat.h>
#include <fnmatch.h>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#ifndef NO_NAMESPACES
using namespace std;
#endif /* NO_NAMESPACES */
#include "rcldb.h"
#include "textsplit.h"
#include "transcode.h"
#include "unacpp.h"
#include "conftree.h"
#include "debuglog.h"
#include "pathut.h"
#include "smallut.h"
#include "pathhash.h"
#include "utf8iter.h"
#include "wipedir.h"
#include "xapian.h"
#include <xapian/stem.h>
#ifndef MAX
#define MAX(A,B) (A>B?A:B)
#endif
#ifndef MIN
#define MIN(A,B) (A<B?A:B)
#endif
#ifndef NO_NAMESPACES
namespace Rcl {
#endif
// This is how long an abstract we keep or build from beginning of text when
// indexing. It only has an influence on the size of the db as we are free
// to shorten it again when displaying
#define INDEX_ABSTRACT_SIZE 250
// This is the size of the abstract that we synthetize out of query
// term contexts at query time
#define MA_ABSTRACT_SIZE 250
// This is how many words (context size) we keep around query terms
// when building the abstract
#define MA_EXTRACT_WIDTH 4
// Truncate longer path and uniquize with hash . The goal for this is
// to avoid xapian max term length limitations, not to gain space (we
// gain very little even with very short maxlens like 30)
#define PATHHASHLEN 150
// Synthetic abstract marker (to discriminate from abstract actually
// found in doc)
const static string rclSyntAbs = "?!#@";
// Data for a xapian database. There could actually be 2 different
// ones for indexing or query as there is not much in common.
class Native {
public:
bool m_isopen;
bool m_iswritable;
Db::OpenMode m_mode;
string m_basedir;
// List of directories for additional databases to query
list<string> m_extraDbs;
// Indexing
Xapian::WritableDatabase wdb;
vector<bool> updated;
// Querying
Xapian::Database db;
Xapian::Query query; // query descriptor: terms and subqueries
// joined by operators (or/and etc...)
Xapian::Enquire *enquire; // Open query descriptor.
Xapian::MSet mset; // Partial result set
string makeAbstract(Xapian::docid id, const list<string>& terms);
bool dbDataToRclDoc(std::string &data, Doc &doc,
int qopts,
Xapian::docid docid,
const list<string>& terms);
Native()
: m_isopen(false), m_iswritable(false), m_mode(Db::DbRO), enquire(0)
{ }
~Native() {
delete enquire;
}
bool filterMatch(Db *rdb, Xapian::Document &xdoc) {
// Parse xapian document's data and populate doc fields
string data = xdoc.get_data();
ConfSimple parms(&data);
// The only filtering for now is on file path (subtree)
string url;
parms.get(string("url"), url);
url = url.substr(7);
if (url.find(rdb->m_asdata.topdir) == 0)
return true;
return false;
}
};
Db::Db()
: m_qOpts(0)
{
m_ndb = new Native;
}
Db::~Db()
{
LOGDEB1(("Db::~Db\n"));
if (m_ndb == 0)
return;
LOGDEB(("Db::~Db: isopen %d m_iswritable %d\n", m_ndb->m_isopen,
m_ndb->m_iswritable));
if (m_ndb->m_isopen == false)
return;
const char *ermsg = "Unknown error";
try {
LOGDEB(("Db::~Db: closing native database\n"));
if (m_ndb->m_iswritable == true) {
m_ndb->wdb.flush();
}
delete m_ndb;
m_ndb = 0;
return;
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (const string &s) {
ermsg = s.c_str();
} catch (const char *s) {
ermsg = s;
} catch (...) {
ermsg = "Caught unknown exception";
}
LOGERR(("Db::~Db: got exception: %s\n", ermsg));
}
bool Db::open(const string& dir, OpenMode mode, int qops)
{
if (m_ndb == 0)
return false;
LOGDEB(("Db::open: m_isopen %d m_iswritable %d\n", m_ndb->m_isopen,
m_ndb->m_iswritable));
if (m_ndb->m_isopen) {
// We used to return an error here but I see no reason to
if (!close())
return false;
}
const char *ermsg = "Unknown";
try {
switch (mode) {
case DbUpd:
case DbTrunc:
{
int action = (mode == DbUpd) ? Xapian::DB_CREATE_OR_OPEN :
Xapian::DB_CREATE_OR_OVERWRITE;
m_ndb->wdb = Xapian::WritableDatabase(dir, action);
LOGDEB(("Db::open: lastdocid: %d\n",
m_ndb->wdb.get_lastdocid()));
m_ndb->updated.resize(m_ndb->wdb.get_lastdocid() + 1);
for (unsigned int i = 0; i < m_ndb->updated.size(); i++)
m_ndb->updated[i] = false;
m_ndb->m_iswritable = true;
}
break;
case DbRO:
default:
m_ndb->m_iswritable = false;
m_ndb->db = Xapian::Database(dir);
for (list<string>::iterator it = m_ndb->m_extraDbs.begin();
it != m_ndb->m_extraDbs.end(); it++) {
string aerr;
LOGDEB(("Db::Open: adding query db [%s]\n", it->c_str()));
aerr.clear();
try {
// Make this non-fatal
m_ndb->db.add_database(Xapian::Database(*it));
} catch (const Xapian::Error &e) {
aerr = e.get_msg().c_str();
} catch (const string &s) {
aerr = s.c_str();
} catch (const char *s) {
aerr = s;
} catch (...) {
aerr = "Caught unknown exception";
}
if (!aerr.empty())
LOGERR(("Db::Open: error while trying to add database "
"from [%s]: %s\n", it->c_str(), aerr.c_str()));
}
break;
}
m_qOpts = qops;
m_ndb->m_mode = mode;
m_ndb->m_isopen = true;
m_ndb->m_basedir = dir;
return true;
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (const string &s) {
ermsg = s.c_str();
} catch (const char *s) {
ermsg = s;
} catch (...) {
ermsg = "Caught unknown exception";
}
LOGERR(("Db::open: exception while opening [%s]: %s\n",
dir.c_str(), ermsg));
return false;
}
string Db::getDbDir()
{
if (m_ndb == 0)
return "";
return m_ndb->m_basedir;
}
// Note: xapian has no close call, we delete and recreate the db
bool Db::close()
{
if (m_ndb == 0)
return false;
LOGDEB(("Db::close(): m_isopen %d m_iswritable %d\n", m_ndb->m_isopen,
m_ndb->m_iswritable));
if (m_ndb->m_isopen == false)
return true;
const char *ermsg = "Unknown";
try {
if (m_ndb->m_iswritable == true) {
m_ndb->wdb.flush();
LOGDEB(("Rcl:Db: Called xapian flush\n"));
}
delete m_ndb;
m_ndb = new Native;
if (m_ndb)
return true;
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (const string &s) {
ermsg = s.c_str();
} catch (const char *s) {
ermsg = s;
} catch (...) {
ermsg = "Caught unknown exception";
}
LOGERR(("Db:close: exception while deleting db: %s\n", ermsg));
return false;
}
bool Db::reOpen()
{
if (m_ndb->m_isopen) {
if (!close())
return false;
if (!open(m_ndb->m_basedir, m_ndb->m_mode, m_qOpts)) {
return false;
}
}
return true;
}
bool Db::addQueryDb(const string &dir)
{
LOGDEB(("Db::addQueryDb: ndb %p iswritable %d db [%s]\n", m_ndb,
(m_ndb)?m_ndb->m_iswritable:0, dir.c_str()));
if (!m_ndb)
return false;
if (m_ndb->m_iswritable)
return false;
if (find(m_ndb->m_extraDbs.begin(), m_ndb->m_extraDbs.end(), dir) ==
m_ndb->m_extraDbs.end()) {
m_ndb->m_extraDbs.push_back(dir);
}
return reOpen();
}
bool Db::rmQueryDb(const string &dir)
{
if (!m_ndb)
return false;
if (m_ndb->m_iswritable)
return false;
if (dir.empty()) {
m_ndb->m_extraDbs.clear();
} else {
list<string>::iterator it = find(m_ndb->m_extraDbs.begin(),
m_ndb->m_extraDbs.end(), dir);
if (it != m_ndb->m_extraDbs.end()) {
m_ndb->m_extraDbs.erase(it);
}
}
return reOpen();
}
bool Db::testDbDir(const string &dir)
{
string aerr;
LOGDEB(("Db::testDbDir: [%s]\n", dir.c_str()));
try {
Xapian::Database db(dir);
} catch (const Xapian::Error &e) {
aerr = e.get_msg().c_str();
} catch (const string &s) {
aerr = s.c_str();
} catch (const char *s) {
aerr = s;
} catch (...) {
aerr = "Caught unknown exception";
}
if (!aerr.empty()) {
LOGERR(("Db::Open: error while trying to open database "
"from [%s]: %s\n", dir.c_str(), aerr.c_str()));
return false;
}
return true;
}
bool Db::isopen()
{
if (m_ndb == 0)
return false;
return m_ndb->m_isopen;
}
// A small class to hold state while splitting text
class mySplitterCB : public TextSplitCB {
public:
Xapian::Document &doc;
Xapian::termpos basepos; // Base for document section
Xapian::termpos curpos; // Last position sent to callback
mySplitterCB(Xapian::Document &d) : doc(d), basepos(1), curpos(0)
{}
bool takeword(const std::string &term, int pos, int, int);
};
// Callback for the document to word splitting class during indexation
bool mySplitterCB::takeword(const std::string &term, int pos, int, int)
{
#if 0
LOGDEB(("mySplitterCB::takeword:splitCb: [%s]\n", term.c_str()));
string printable;
if (transcode(term, printable, "UTF-8", "ISO-8859-1")) {
LOGDEB((" [%s]\n", printable.c_str()));
}
#endif
const char *ermsg;
try {
// Note: 1 is the within document frequency increment. It would
// be possible to assign different weigths to doc parts (ie title)
// by using a higher value
curpos = pos;
doc.add_posting(term, basepos + curpos, 1);
return true;
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (...) {
ermsg= "Unknown error";
}
LOGERR(("Db: xapian add_posting error %s\n", ermsg));
return false;
}
// Unaccent and lowercase data, replace \n\r with spaces
// Removing crlfs is so that we can use the text in the document data fields.
// Use unac (with folding extension) for removing accents and casefolding
//
// Note that we always return true (but set out to "" on error). We don't
// want to stop indexation because of a bad string
bool dumb_string(const string &in, string &out)
{
out.erase();
if (in.empty())
return true;
string s1 = neutchars(in, "\n\r");
if (!unacmaybefold(s1, out, "UTF-8", true)) {
LOGERR(("dumb_string: unac failed for %s\n", in.c_str()));
out.erase();
// See comment at start of func
return true;
}
return true;
}
// Add document in internal form to the database: index the terms in
// the title abstract and body and add special terms for file name,
// date, mime type ... , create the document data record (more
// metadata), and update database
bool Db::add(const string &fn, const Doc &idoc,
const struct stat *stp)
{
LOGDEB1(("Db::add: fn %s\n", fn.c_str()));
if (m_ndb == 0)
return false;
Doc doc = idoc;
// Truncate abstract, title and keywords to reasonable lengths. If
// abstract is currently empty, we make up one with the beginning
// of the document.
if (doc.abstract.empty()) {
doc.abstract = rclSyntAbs +
truncate_to_word(doc.text, INDEX_ABSTRACT_SIZE);
} else {
doc.abstract = truncate_to_word(doc.abstract, INDEX_ABSTRACT_SIZE);
}
doc.abstract = neutchars(doc.abstract, "\n\r");
doc.title = truncate_to_word(doc.title, 100);
doc.keywords = truncate_to_word(doc.keywords, 300);
Xapian::Document newdocument;
mySplitterCB splitData(newdocument);
TextSplit splitter(&splitData);
// /////// Split and index terms in document body and auxiliary fields
string noacc;
// Split and index file name as document term(s)
if (dumb_string(doc.utf8fn, noacc)) {
splitter.text_to_words(noacc);
splitData.basepos += splitData.curpos + 100;
}
// Split and index title
if (!dumb_string(doc.title, noacc)) {
LOGERR(("Db::add: dumb_string failed\n"));
return false;
}
splitter.text_to_words(noacc);
splitData.basepos += splitData.curpos + 100;
// Split and index body
if (!dumb_string(doc.text, noacc)) {
LOGERR(("Db::add: dumb_string failed\n"));
return false;
}
splitter.text_to_words(noacc);
splitData.basepos += splitData.curpos + 100;
// Split and index keywords
if (!dumb_string(doc.keywords, noacc)) {
LOGERR(("Db::add: dumb_string failed\n"));
return false;
}
splitter.text_to_words(noacc);
splitData.basepos += splitData.curpos + 100;
// Split and index abstract
if (!dumb_string(doc.abstract, noacc)) {
LOGERR(("Db::add: dumb_string failed\n"));
return false;
}
splitter.text_to_words(noacc);
splitData.basepos += splitData.curpos + 100;
////// Special terms for metadata
// Mime type
newdocument.add_term("T" + doc.mimetype);
// Simple file name. This is used for file name searches only. We index
// it with a term prefix. utf8fn used to be the full path, but it's now
// the simple file name.
if (dumb_string(doc.utf8fn, noacc) && !noacc.empty()) {
noacc = string("XSFN") + noacc;
newdocument.add_term(noacc);
}
// Pathname/ipath terms. This is used for file existence/uptodate
// checks, and unique id for the replace_document() call
// Truncate the filepath part to a reasonable length and
// replace the truncated part with a hopefully unique hash
string hash;
pathHash(fn, hash, PATHHASHLEN);
LOGDEB2(("Db::add: pathhash [%s]\n", hash.c_str()));
string pathterm = "P" + hash;
newdocument.add_term(pathterm);
// Unique term: with path, makes unique identifier for documents
// inside multidocument files.
string uniterm;
if (doc.ipath.empty()) {
uniterm = pathterm;
} else {
uniterm = "Q" + hash + "|" + doc.ipath;
newdocument.add_term(uniterm);
}
// Dates etc...
time_t mtime = atol(doc.dmtime.empty() ? doc.fmtime.c_str() :
doc.dmtime.c_str());
struct tm *tm = localtime(&mtime);
char buf[9];
sprintf(buf, "%04d%02d%02d",tm->tm_year+1900, tm->tm_mon + 1, tm->tm_mday);
newdocument.add_term("D" + string(buf)); // Date (YYYYMMDD)
buf[7] = '\0';
if (buf[6] == '3') buf[6] = '2';
newdocument.add_term("W" + string(buf)); // "Weak" - 10ish day interval
buf[6] = '\0';
newdocument.add_term("M" + string(buf)); // Month (YYYYMM)
buf[4] = '\0';
newdocument.add_term("Y" + string(buf)); // Year (YYYY)
// Document data record. omindex has the following nl separated fields:
// - url
// - sample
// - caption (title limited to 100 chars)
// - mime type
string record = "url=file://" + fn;
record += "\nmtype=" + doc.mimetype;
record += "\nfmtime=" + doc.fmtime;
if (!doc.dmtime.empty()) {
record += "\ndmtime=" + doc.dmtime;
}
record += "\norigcharset=" + doc.origcharset;
char sizebuf[20];
sizebuf[0] = 0;
if (stp)
sprintf(sizebuf, "%ld", (long)stp->st_size);
if (sizebuf[0])
record += string("\nfbytes=") + sizebuf;
sprintf(sizebuf, "%u", (unsigned int)doc.text.length());
record += string("\ndbytes=") + sizebuf;
if (!doc.ipath.empty()) {
record += "\nipath=" + doc.ipath;
}
record += "\ncaption=" + doc.title;
record += "\nkeywords=" + doc.keywords;
record += "\nabstract=" + doc.abstract;
record += "\n";
LOGDEB1(("Newdocument data: %s\n", record.c_str()));
newdocument.set_data(record);
const char *fnc = fn.c_str();
// Add db entry or update existing entry:
try {
Xapian::docid did =
m_ndb->wdb.replace_document(uniterm, newdocument);
if (did < m_ndb->updated.size()) {
m_ndb->updated[did] = true;
LOGDEB(("Db::add: docid %d updated [%s , %s]\n", did, fnc,
doc.ipath.c_str()));
} else {
LOGDEB(("Db::add: docid %d added [%s , %s]\n", did, fnc,
doc.ipath.c_str()));
}
} catch (...) {
// FIXME: is this ever actually needed?
try {
m_ndb->wdb.add_document(newdocument);
LOGDEB(("Db::add: %s added (failed re-seek for duplicate)\n",
fnc));
} catch (...) {
LOGERR(("Db::add: failed again after replace_document\n"));
return false;
}
}
return true;
}
// Test if given filename has changed since last indexed:
bool Db::needUpdate(const string &filename, const struct stat *stp)
{
if (m_ndb == 0)
return false;
// If no document exist with this path, we do need update
string hash;
pathHash(filename, hash, PATHHASHLEN);
string pathterm = "P" + hash;
const char *ermsg;
// Look for all documents with this path. We need to look at all
// to set their existence flag. We check the update time on the
// fmtime field which will be identical for all docs inside a
// multi-document file (we currently always reindex all if the
// file changed)
Xapian::PostingIterator doc;
try {
if (!m_ndb->wdb.term_exists(pathterm)) {
LOGDEB1(("Db::needUpdate: no such path: %s\n", pathterm.c_str()));
return true;
}
Xapian::PostingIterator docid0 = m_ndb->wdb.postlist_begin(pathterm);
for (Xapian::PostingIterator docid = docid0;
docid != m_ndb->wdb.postlist_end(pathterm); docid++) {
Xapian::Document doc = m_ndb->wdb.get_document(*docid);
// Check the date once. no need to look at the others if
// the db needs updating. Note that the fmtime used to be
// called mtime, and we're keeping compat
if (docid == docid0) {
string data = doc.get_data();
const char *cp = strstr(data.c_str(), "fmtime=");
if (cp) {
cp += 7;
} else {
cp = strstr(data.c_str(), "mtime=");
if (cp)
cp+= 6;
}
long mtime = cp ? atol(cp) : 0;
if (mtime < stp->st_mtime) {
LOGDEB2(("Db::needUpdate: yes: mtime: Db %ld file %ld\n",
(long)mtime, (long)stp->st_mtime));
// Db is not up to date. Let's index the file
return true;
}
}
// Db is up to date. Make a note that this document exists.
if (*docid < m_ndb->updated.size())
m_ndb->updated[*docid] = true;
}
return false;
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (...) {
ermsg= "Unknown error";
}
LOGERR(("Db::needUpdate: error while checking existence: %s\n", ermsg));
return true;
}
const static string stemdirstem = "stem_";
/// Compute name of stem db for given base database and language
static string stemdbname(const string& basename, string lang)
{
string nm = path_cat(basename, stemdirstem + lang);
return nm;
}
// Return list of existing stem db languages
list<string> Db::getStemLangs()
{
list<string> dirs;
LOGDEB(("Db::getStemLang\n"));
if (m_ndb == 0)
return dirs;
string pattern = stemdirstem + "*";
dirs = path_dirglob(m_ndb->m_basedir, pattern);
for (list<string>::iterator it = dirs.begin(); it != dirs.end(); it++) {
*it = path_basename(*it);
*it = it->substr(stemdirstem.length(), string::npos);
}
return dirs;
}
/**
* Delete stem db for given language
*/
bool Db::deleteStemDb(const string& lang)
{
LOGDEB(("Db::deleteStemDb(%s)\n", lang.c_str()));
if (m_ndb == 0)
return false;
if (m_ndb->m_isopen == false)
return false;
string dir = stemdbname(m_ndb->m_basedir, lang);
if (wipedir(dir) == 0 && rmdir(dir.c_str()) == 0)
return true;
return false;
}
// Deciding if we try to stem the term. If it has numerals or capitals
// we don't
inline static bool
p_notlowerascii(unsigned int c)
{
if (c < 'a' || (c > 'z' && c < 128))
return true;
return false;
}
/**
* Create database of stem to parents associations for a given language.
* We walk the list of all terms, stem them, and create another Xapian db
* with documents indexed by a single term (the stem), and with the list of
* parent terms in the document data.
*/
bool Db::createStemDb(const string& lang)
{
LOGDEB(("Db::createStemDb(%s)\n", lang.c_str()));
if (m_ndb == 0)
return false;
if (m_ndb->m_isopen == false)
return false;
// First build the in-memory stem database:
// We walk the list of all terms, and stem each.
// If the stem is identical to the term, no need to create an entry
// Else, we add an entry to the multimap.
// At the end, we only save stem-terms associations with several terms, the
// others are not useful
// Note: a map<string, list<string> > would probably be more efficient
multimap<string, string> assocs;
// Statistics
int nostem=0; // Dont even try: not-alphanum (incomplete for now)
int stemconst=0; // Stem == term
int stemdiff=0; // Count of all different stems
int stemmultiple = 0; // Count of stems with multiple derivatives
try {
Xapian::Stem stemmer(lang);
Xapian::TermIterator it;
for (it = m_ndb->wdb.allterms_begin();
it != m_ndb->wdb.allterms_end(); it++) {
// If it has any non-lowercase 7bit char, cant be stemmable
string::iterator sit = (*it).begin(), eit = sit + (*it).length();
if ((sit = find_if(sit, eit, p_notlowerascii)) != eit) {
++nostem;
// LOGDEB(("stemskipped: [%s], because of 0x%x\n",
// (*it).c_str(), *sit));
continue;
}
string stem = stemmer.stem_word(*it);
//cerr << "word " << *it << " stem " << stem << endl;
if (stem == *it) {
++stemconst;
continue;
}
assocs.insert(pair<string,string>(stem, *it));
}
} catch (const Xapian::Error &e) {
LOGERR(("Db::createStemDb: build failed: %s\n", e.get_msg().c_str()));
return false;
} catch (...) {
LOGERR(("Db::createStemDb: build failed: no stemmer for %s ? \n",
lang.c_str()));
return false;
}
class DirWiper {
public:
string dir;
bool do_it;
DirWiper(string d) : dir(d), do_it(true) {}
~DirWiper() {
if (do_it) {
wipedir(dir);
rmdir(dir.c_str());
}
}
};
// Create xapian database for stem relations
string stemdbdir = stemdbname(m_ndb->m_basedir, lang);
// We want to get rid of the db dir in case of error. This gets disarmed
// just before success return.
DirWiper wiper(stemdbdir);
const char *ermsg = "NOERROR";
Xapian::WritableDatabase sdb;
try {
sdb = Xapian::WritableDatabase(stemdbdir,
Xapian::DB_CREATE_OR_OVERWRITE);
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (const string &s) {
ermsg = s.c_str();
} catch (const char *s) {
ermsg = s;
} catch (...) {
ermsg = "Caught unknown exception";
}
if (ermsg != "NOERROR") {
LOGERR(("Db::createstemdb: exception while opening [%s]: %s\n",
stemdbdir.c_str(), ermsg));
return false;
}
// Enter pseud-docs in db. Walk the multimap, only enter
// associations where there are several parent terms
string stem;
list<string> derivs;
for (multimap<string,string>::const_iterator it = assocs.begin();
it != assocs.end(); it++) {
if (stem == it->first) {
// Staying with same stem
derivs.push_back(it->second);
// cerr << " " << it->second << endl;
} else {
// Changing stems
++stemdiff;
if (derivs.size() == 1) {
// Exactly one term stems to this. Check for the case where
// the stem itself exists as a term. The code above would not
// have inserted anything in this case.
if (m_ndb->wdb.term_exists(stem))
derivs.push_back(stem);
}
if (derivs.size() > 1) {
// Previous stem has multiple derivatives. Enter in db
++stemmultiple;
Xapian::Document newdocument;
newdocument.add_term(stem);
// The doc data is just parents=blank-separated-list
string record = "parents=";
for (list<string>::const_iterator it = derivs.begin();
it != derivs.end(); it++) {
record += *it + " ";
}
record += "\n";
LOGDEB1(("stemdocument data: %s\n", record.c_str()));
newdocument.set_data(record);
try {
sdb.replace_document(stem, newdocument);
} catch (...) {
LOGERR(("Db::createstemdb: replace failed\n"));
return false;
}
}
derivs.clear();
stem = it->first;
derivs.push_back(it->second);
// cerr << "\n" << stem << " " << it->second;
}
}
LOGDEB(("Stem map size: %d stems %d mult %d no %d const %d\n",
assocs.size(), stemdiff, stemmultiple, nostem, stemconst));
wiper.do_it = false;
return true;
}
/**
* This is called at the end of an indexing session, to delete the
* documents for files that are no longer there.
*/
bool Db::purge()
{
LOGDEB(("Db::purge\n"));
if (m_ndb == 0)
return false;
LOGDEB(("Db::purge: m_isopen %d m_iswritable %d\n", m_ndb->m_isopen,
m_ndb->m_iswritable));
if (m_ndb->m_isopen == false || m_ndb->m_iswritable == false)
return false;
// There seems to be problems with the document delete code, when
// we do this, the database is not actually updated. Especially,
// if we delete a bunch of docs, so that there is a hole in the
// docids at the beginning, we can't add anything (appears to work
// and does nothing). Maybe related to the exceptions below when
// trying to delete an unexistant document ?
// Flushing before trying the deletes seeems to work around the problem
try {
m_ndb->wdb.flush();
} catch (...) {
LOGDEB(("Db::purge: 1st flush failed\n"));
}
for (Xapian::docid docid = 1; docid < m_ndb->updated.size(); ++docid) {
if (!m_ndb->updated[docid]) {
try {
m_ndb->wdb.delete_document(docid);
LOGDEB(("Db::purge: deleted document #%d\n", docid));
} catch (const Xapian::DocNotFoundError &) {
LOGDEB(("Db::purge: document #%d not found\n", docid));
}
}
}
try {
m_ndb->wdb.flush();
} catch (...) {
LOGDEB(("Db::purge: 2nd flush failed\n"));
}
return true;
}
/**
* Expand term to list of all terms which stem to the same term.
*/
static list<string> stemexpand(Native *m_ndb, string term, const string& lang)
{
list<string> explist;
try {
Xapian::Stem stemmer(lang);
string stem = stemmer.stem_word(term);
LOGDEB(("stemexpand: [%s] stem-> [%s]\n", term.c_str(), stem.c_str()));
// Try to fetch the doc from the stem db
string stemdbdir = stemdbname(m_ndb->m_basedir, lang);
Xapian::Database sdb(stemdbdir);
LOGDEB1(("stemexpand: %s lastdocid: %d\n",
stemdbdir.c_str(), sdb.get_lastdocid()));
if (!sdb.term_exists(stem)) {
LOGDEB1(("Db::stemexpand: no term for %s\n", stem.c_str()));
explist.push_back(term);
return explist;
}
Xapian::PostingIterator did = sdb.postlist_begin(stem);
if (did == sdb.postlist_end(stem)) {
LOGDEB1(("stemexpand: no term(1) for %s\n",stem.c_str()));
explist.push_back(term);
return explist;
}
Xapian::Document doc = sdb.get_document(*did);
string data = doc.get_data();
// No need for a conftree, but we need to massage the data a little
string::size_type pos = data.find_first_of("=");
++pos;
string::size_type pos1 = data.find_last_of("\n");
if (pos == string::npos || pos1 == string::npos ||pos1 <= pos) { // ??
explist.push_back(term);
return explist;
}
stringToStrings(data.substr(pos, pos1-pos), explist);
if (find(explist.begin(), explist.end(), term) == explist.end()) {
explist.push_back(term);
}
LOGDEB(("stemexpand: %s -> %s\n", stem.c_str(),
stringlistdisp(explist).c_str()));
} catch (...) {
LOGERR(("stemexpand: error accessing stem db\n"));
explist.push_back(term);
return explist;
}
return explist;
}
// Splitter callback for breaking query into terms
class wsQData : public TextSplitCB {
public:
vector<string> terms;
string catterms() {
string s;
for (unsigned int i=0;i<terms.size();i++) {
s += "[" + terms[i] + "] ";
}
return s;
}
bool takeword(const std::string &term, int , int, int) {
LOGDEB1(("wsQData::takeword: %s\n", term.c_str()));
terms.push_back(term);
return true;
}
void dumball() {
for (vector<string>::iterator it=terms.begin(); it !=terms.end();it++){
string dumb;
dumb_string(*it, dumb);
*it = dumb;
}
}
};
// Turn string into list of xapian queries. There is little
// interpretation done on the string (no +term -term or filename:term
// stuff). We just separate words and phrases, and interpret
// capitalized terms as wanting no stem expansion.
// The final list contains one query for each term or phrase
// - Elements corresponding to a stem-expanded part are an OP_OR
// composition of the stem-expanded terms (or a single term query).
// - Elements corresponding to a phrase are an OP_PHRASE composition of the
// phrase terms (no stem expansion in this case)
static void stringToXapianQueries(const string &iq,
const string& stemlang,
Native *m_ndb,
list<Xapian::Query> &pqueries,
Db::QueryOpts opts = Db::QO_NONE)
{
string qstring = iq;
// Split into (possibly single word) phrases ("this is a phrase"):
list<string> phrases;
stringToStrings(qstring, phrases);
// Then process each phrase: split into terms and transform into
// appropriate Xapian Query
for (list<string>::iterator it=phrases.begin(); it !=phrases.end(); it++) {
LOGDEB(("strToXapianQ: phrase or word: [%s]\n", it->c_str()));
wsQData splitData;
TextSplit splitter(&splitData, true);
splitter.text_to_words(*it);
LOGDEB1(("strToXapianQ: splitter term count: %d\n",
splitData.terms.size()));
switch(splitData.terms.size()) {
case 0: continue;// ??
case 1: // Not a real phrase: one term
{
string term = splitData.terms.front();
bool nostemexp = false;
// Check if the first letter is a majuscule in which
// case we do not want to do stem expansion. Note that
// the test is convoluted and possibly problematic
if (term.length() > 0) {
string noacterm,noaclowterm;
if (unacmaybefold(term, noacterm, "UTF-8", false) &&
unacmaybefold(noacterm, noaclowterm, "UTF-8", true)) {
Utf8Iter it1(noacterm);
Utf8Iter it2(noaclowterm);
if (*it1 != *it2)
nostemexp = true;
}
}
LOGDEB1(("Term: %s stem expansion: %s\n",
term.c_str(), nostemexp?"no":"yes"));
list<string> exp;
string term1;
dumb_string(term, term1);
// Possibly perform stem compression/expansion
if (!nostemexp && (opts & Db::QO_STEM)) {
exp = stemexpand(m_ndb, term1, stemlang);
} else {
exp.push_back(term1);
}
// Push either term or OR of stem-expanded set
pqueries.push_back(Xapian::Query(Xapian::Query::OP_OR,
exp.begin(), exp.end()));
}
break;
default:
// Phrase: no stem expansion
splitData.dumball();
LOGDEB(("Pushing phrase: [%s]\n", splitData.catterms().c_str()));
pqueries.push_back(Xapian::Query(Xapian::Query::OP_PHRASE,
splitData.terms.begin(),
splitData.terms.end()));
}
}
}
// Prepare query out of simple query string
bool Db::setQuery(const std::string &iqstring, QueryOpts opts,
const string& stemlang)
{
LOGDEB(("Db::setQuery: q: [%s], opts 0x%x, stemlang %s\n",
iqstring.c_str(), (unsigned int)opts, stemlang.c_str()));
if (!m_ndb)
return false;
m_asdata.erase();
m_dbindices.clear();
list<Xapian::Query> pqueries;
stringToXapianQueries(iqstring, stemlang, m_ndb, pqueries, opts);
m_ndb->query = Xapian::Query(Xapian::Query::OP_OR, pqueries.begin(),
pqueries.end());
delete m_ndb->enquire;
m_ndb->enquire = new Xapian::Enquire(m_ndb->db);
m_ndb->enquire->set_query(m_ndb->query);
m_ndb->mset = Xapian::MSet();
return true;
}
// Prepare query out of "advanced search" data
bool Db::setQuery(AdvSearchData &sdata, QueryOpts opts,
const string& stemlang)
{
LOGDEB(("Db::setQuery: adv:\n"));
LOGDEB((" allwords: %s\n", sdata.allwords.c_str()));
LOGDEB((" phrase: %s\n", sdata.phrase.c_str()));
LOGDEB((" orwords: %s\n", sdata.orwords.c_str()));
LOGDEB((" nowords: %s\n", sdata.nowords.c_str()));
string ft;
for (list<string>::iterator it = sdata.filetypes.begin();
it != sdata.filetypes.end(); it++) {ft += *it + " ";}
if (!ft.empty())
LOGDEB((" searched file types: %s\n", ft.c_str()));
if (!sdata.topdir.empty())
LOGDEB((" restricted to: %s\n", sdata.topdir.c_str()));
m_asdata = sdata;
m_dbindices.clear();
if (!m_ndb)
return false;
list<Xapian::Query> pqueries;
Xapian::Query xq;
if (!sdata.filename.empty()) {
LOGDEB((" filename search\n"));
// File name search, with possible wildcards.
// We expand wildcards by scanning the filename terms (prefixed
// with XSFN) from the database.
// We build an OR query with the expanded values if any.
string pattern;
dumb_string(sdata.filename, pattern);
// If pattern is not quoted, and has no wildcards, we add * at
// each end: match any substring
if (pattern[0] == '"' && pattern[pattern.size()-1] == '"') {
pattern = pattern.substr(1, pattern.size() -2);
} else if (pattern.find_first_of("*?[") == string::npos) {
pattern = "*" + pattern + "*";
} // else let it be
LOGDEB((" pattern: [%s]\n", pattern.c_str()));
// Match pattern against all file names in the db
Xapian::TermIterator it = m_ndb->db.allterms_begin();
it.skip_to("XSFN");
list<string> names;
for (;it != m_ndb->db.allterms_end(); it++) {
if ((*it).find("XSFN") != 0)
break;
string fn = (*it).substr(4);
LOGDEB2(("Matching [%s] and [%s]\n", pattern.c_str(), fn.c_str()));
if (fnmatch(pattern.c_str(), fn.c_str(), 0) != FNM_NOMATCH) {
names.push_back((*it).c_str());
}
// Limit the match count
if (names.size() > 1000) {
LOGERR(("Db::SetQuery: too many matched file names\n"));
break;
}
}
if (names.empty()) {
// Build an impossible query: we know its impossible because we
// control the prefixes!
names.push_back("XIMPOSSIBLE");
}
// Build a query out of the matching file name terms.
xq = Xapian::Query(Xapian::Query::OP_OR, names.begin(), names.end());
}
if (!sdata.allwords.empty()) {
stringToXapianQueries(sdata.allwords, stemlang, m_ndb, pqueries, opts);
if (!pqueries.empty()) {
Xapian::Query nq =
Xapian::Query(Xapian::Query::OP_AND, pqueries.begin(),
pqueries.end());
xq = xq.empty() ? nq :
Xapian::Query(Xapian::Query::OP_AND, xq, nq);
pqueries.clear();
}
}
if (!sdata.orwords.empty()) {
stringToXapianQueries(sdata.orwords, stemlang, m_ndb, pqueries, opts);
if (!pqueries.empty()) {
Xapian::Query nq =
Xapian::Query(Xapian::Query::OP_OR, pqueries.begin(),
pqueries.end());
xq = xq.empty() ? nq :
Xapian::Query(Xapian::Query::OP_AND_MAYBE, xq, nq);
pqueries.clear();
}
}
if (!sdata.phrase.empty()) {
Xapian::Query nq;
string s = string("\"") + sdata.phrase + string("\"");
stringToXapianQueries(s, stemlang, m_ndb, pqueries);
if (!pqueries.empty()) {
// There should be a single list element phrase query.
xq = xq.empty() ? *pqueries.begin() :
Xapian::Query(Xapian::Query::OP_AND, xq, *pqueries.begin());
pqueries.clear();
}
}
if (!sdata.filetypes.empty()) {
Xapian::Query tq;
for (list<string>::iterator it = sdata.filetypes.begin();
it != sdata.filetypes.end(); it++) {
string term = "T" + *it;
LOGDEB(("Adding file type term: [%s]\n", term.c_str()));
tq = tq.empty() ? Xapian::Query(term) :
Xapian::Query(Xapian::Query::OP_OR, tq, Xapian::Query(term));
}
xq = xq.empty() ? tq : Xapian::Query(Xapian::Query::OP_FILTER, xq, tq);
}
// "And not" part. Must come last, as we have to check it's not
// the only term in the query. We do no stem expansion on 'No'
// words. Should we ?
if (!sdata.nowords.empty()) {
stringToXapianQueries(sdata.nowords, stemlang, m_ndb, pqueries);
if (!pqueries.empty()) {
Xapian::Query nq;
nq = Xapian::Query(Xapian::Query::OP_OR, pqueries.begin(),
pqueries.end());
if (xq.empty()) {
// Xapian cant do this currently. Have to have a positive
// part!
sdata.description = "Error: pure negative query\n";
LOGERR(("Rcl::Db::setQuery: error: pure negative query\n"));
return false;
}
xq = Xapian::Query(Xapian::Query::OP_AND_NOT, xq, nq);
pqueries.clear();
}
}
m_ndb->query = xq;
delete m_ndb->enquire;
m_ndb->enquire = new Xapian::Enquire(m_ndb->db);
m_ndb->enquire->set_query(m_ndb->query);
m_ndb->mset = Xapian::MSet();
// Get the query description and trim the "Xapian::Query"
sdata.description = m_ndb->query.get_description();
if (sdata.description.find("Xapian::Query") == 0)
sdata.description = sdata.description.substr(strlen("Xapian::Query"));
LOGDEB(("Db::SetQuery: Q: %s\n", sdata.description.c_str()));
return true;
}
bool Db::getQueryTerms(list<string>& terms)
{
if (!m_ndb)
return false;
terms.clear();
Xapian::TermIterator it;
for (it = m_ndb->query.get_terms_begin(); it != m_ndb->query.get_terms_end();
it++) {
terms.push_back(*it);
}
return true;
}
// Mset size
static const int qquantum = 30;
int Db::getResCnt()
{
if (!m_ndb || !m_ndb->enquire) {
LOGERR(("Db::getResCnt: no query opened\n"));
return -1;
}
if (m_ndb->mset.size() <= 0) {
try {
m_ndb->mset = m_ndb->enquire->get_mset(0, qquantum);
} catch (const Xapian::DatabaseModifiedError &error) {
m_ndb->db.reopen();
m_ndb->mset = m_ndb->enquire->get_mset(0, qquantum);
} catch (const Xapian::Error & error) {
LOGERR(("enquire->get_mset: exception: %s\n",
error.get_msg().c_str()));
return -1;
}
}
return m_ndb->mset.get_matches_lower_bound();
}
bool Native::dbDataToRclDoc(std::string &data, Doc &doc,
int qopts,
Xapian::docid docid, const list<string>& terms)
{
LOGDEB1(("Db::dbDataToRclDoc: data: %s\n", data.c_str()));
ConfSimple parms(&data);
if (!parms.ok())
return false;
parms.get(string("url"), doc.url);
parms.get(string("mtype"), doc.mimetype);
parms.get(string("fmtime"), doc.fmtime);
parms.get(string("dmtime"), doc.dmtime);
parms.get(string("origcharset"), doc.origcharset);
parms.get(string("caption"), doc.title);
parms.get(string("keywords"), doc.keywords);
parms.get(string("abstract"), doc.abstract);
bool syntabs = false;
if (doc.abstract.find(rclSyntAbs) == 0) {
doc.abstract = doc.abstract.substr(rclSyntAbs.length());
syntabs = true;
}
if ((qopts && Db::QO_BUILD_ABSTRACT) && !terms.empty()) {
LOGDEB1(("dbDataToRclDoc:: building abstract from position data\n"));
if (doc.abstract.empty() || syntabs ||
(qopts & Db::QO_REPLACE_ABSTRACT))
doc.abstract = makeAbstract(docid, terms);
}
parms.get(string("ipath"), doc.ipath);
parms.get(string("fbytes"), doc.fbytes);
parms.get(string("dbytes"), doc.dbytes);
return true;
}
// Get document at rank i in query (i is the index in the whole result
// set, as in the enquire class. We check if the current mset has the
// doc, else ask for an other one. We use msets of 10 documents. Don't
// know if the whole thing makes sense at all but it seems to work.
//
// If there is a postquery filter (ie: file names), we have to
// maintain a correspondance from the sequential external index
// sequence to the internal Xapian hole-y one (the holes being the documents
// that dont match the filter).
bool Db::getDoc(int exti, Doc &doc, int *percent)
{
LOGDEB1(("Db::getDoc: exti %d\n", exti));
if (!m_ndb || !m_ndb->enquire) {
LOGERR(("Db::getDoc: no query opened\n"));
return false;
}
// For now the only post-query filter is on dir subtree
bool postqfilter = !m_asdata.topdir.empty();
LOGDEB1(("Topdir %s postqflt %d\n", m_asdata.topdir.c_str(), postqfilter));
int xapi;
if (postqfilter) {
// There is a postquery filter, does this fall in already known area ?
if (exti >= (int)m_dbindices.size()) {
// Have to fetch xapian docs and filter until we get
// enough or fail
m_dbindices.reserve(exti+1);
// First xapian doc we fetch is the one after last stored
int first = m_dbindices.size() > 0 ? m_dbindices.back() + 1 : 0;
// Loop until we get enough docs
while (exti >= (int)m_dbindices.size()) {
LOGDEB(("Db::getDoc: fetching %d starting at %d\n",
qquantum, first));
try {
m_ndb->mset = m_ndb->enquire->get_mset(first, qquantum);
} catch (const Xapian::DatabaseModifiedError &error) {
m_ndb->db.reopen();
m_ndb->mset = m_ndb->enquire->get_mset(first, qquantum);
} catch (const Xapian::Error & error) {
LOGERR(("enquire->get_mset: exception: %s\n",
error.get_msg().c_str()));
abort();
}
if (m_ndb->mset.empty()) {
LOGDEB(("Db::getDoc: got empty mset\n"));
return false;
}
first = m_ndb->mset.get_firstitem();
for (unsigned int i = 0; i < m_ndb->mset.size() ; i++) {
LOGDEB(("Db::getDoc: [%d]\n", i));
Xapian::Document xdoc = m_ndb->mset[i].get_document();
if (m_ndb->filterMatch(this, xdoc)) {
m_dbindices.push_back(first + i);
}
}
first = first + m_ndb->mset.size();
}
}
xapi = m_dbindices[exti];
} else {
xapi = exti;
}
// From there on, we work with a xapian enquire item number. Fetch it
int first = m_ndb->mset.get_firstitem();
int last = first + m_ndb->mset.size() -1;
if (!(xapi >= first && xapi <= last)) {
LOGDEB(("Fetching for first %d, count %d\n", xapi, qquantum));
try {
m_ndb->mset = m_ndb->enquire->get_mset(xapi, qquantum);
} catch (const Xapian::DatabaseModifiedError &error) {
m_ndb->db.reopen();
m_ndb->mset = m_ndb->enquire->get_mset(xapi, qquantum);
} catch (const Xapian::Error & error) {
LOGERR(("enquire->get_mset: exception: %s\n",
error.get_msg().c_str()));
abort();
}
if (m_ndb->mset.empty())
return false;
first = m_ndb->mset.get_firstitem();
last = first + m_ndb->mset.size() -1;
}
LOGDEB1(("Db::getDoc: Qry [%s] win [%d-%d] Estimated results: %d",
m_ndb->query.get_description().c_str(),
first, last,
m_ndb->mset.get_matches_lower_bound()));
Xapian::Document xdoc = m_ndb->mset[xapi-first].get_document();
Xapian::docid docid = *(m_ndb->mset[xapi-first]);
if (percent)
*percent = m_ndb->mset.convert_to_percent(m_ndb->mset[xapi-first]);
// Parse xapian document's data and populate doc fields
string data = xdoc.get_data();
list<string> terms;
getQueryTerms(terms);
return m_ndb->dbDataToRclDoc(data, doc, m_qOpts, docid, terms);
}
// Retrieve document defined by file name and internal path. Very inefficient,
// used only for history display. We'd need to enter path+ipath terms in the
// db if we wanted to make this more efficient.
bool Db::getDoc(const string &fn, const string &ipath, Doc &doc, int *pc)
{
LOGDEB(("Db:getDoc: [%s] (%d) [%s]\n", fn.c_str(), fn.length(),
ipath.c_str()));
if (m_ndb == 0)
return false;
// Initialize what we can in any case. If this is history, caller
// will make partial display in case of error
doc.ipath = ipath;
doc.url = string("file://") + fn;
if (*pc)
*pc = 100;
string hash;
pathHash(fn, hash, PATHHASHLEN);
string pathterm = "P" + hash;
// Look for all documents with this path, searching for the one
// with the appropriate ipath. This is very inefficient.
const char *ermsg = "";
try {
if (!m_ndb->db.term_exists(pathterm)) {
// Document found in history no longer in the database.
// We return true (because their might be other ok docs further)
// but indicate the error with pc = -1
if (*pc)
*pc = -1;
LOGINFO(("Db:getDoc: path inexistant: [%s] length %d\n",
pathterm.c_str(), pathterm.length()));
return true;
}
for (Xapian::PostingIterator docid =
m_ndb->db.postlist_begin(pathterm);
docid != m_ndb->db.postlist_end(pathterm); docid++) {
Xapian::Document xdoc = m_ndb->db.get_document(*docid);
string data = xdoc.get_data();
list<string> terms;
if (m_ndb->dbDataToRclDoc(data, doc, QO_NONE, *docid, terms)
&& doc.ipath == ipath)
return true;
}
} catch (const Xapian::Error &e) {
ermsg = e.get_msg().c_str();
} catch (const string &s) {
ermsg = s.c_str();
} catch (const char *s) {
ermsg = s;
} catch (...) {
ermsg = "Caught unknown exception";
}
if (*ermsg) {
LOGERR(("Db::getDoc: %s\n", ermsg));
}
return false;
}
// Width of a sample extract around a query term
//
// We build a possibly full size but sparsely populated (only around
// the search term) reconstruction of the document. It would be
// possible to compress the array, by having only multiple chunks
// around the terms, but this would seriously complicate the data
// structure.
string Native::makeAbstract(Xapian::docid docid, const list<string>& terms)
{
Chrono chron;
// A buffer that we populate with the document terms, at their position
vector<string> buf;
// Go through the list of query terms. For each entry in each
// position list, populate the slot in the document buffer, and
// remember the position and its neigbours
vector<unsigned int> qtermposs; // The term positions
set<unsigned int> chunkposs; // All the positions we shall populate
for (list<string>::const_iterator qit = terms.begin(); qit != terms.end();
qit++) {
Xapian::PositionIterator pos;
// There may be query terms not in this doc. This raises an
// exception when requesting the position list, we just catch it.
try {
unsigned int occurrences = 0;
for (pos = db.positionlist_begin(docid, *qit);
pos != db.positionlist_end(docid, *qit); pos++) {
unsigned int ipos = *pos;
LOGDEB1(("Abstract: [%s] at %d\n", qit->c_str(), ipos));
// Possibly extend the array. Do it in big chunks
if (ipos + MA_EXTRACT_WIDTH >= buf.size()) {
buf.resize(ipos + MA_EXTRACT_WIDTH + 1000);
}
buf[ipos] = *qit;
// Remember the term position
qtermposs.push_back(ipos);
// Add adjacent slots to the set to populate at next step
for (unsigned int ii = MAX(0, ipos-MA_EXTRACT_WIDTH);
ii <= MIN(ipos+MA_EXTRACT_WIDTH, buf.size()-1); ii++) {
chunkposs.insert(ii);
}
// Limit the number of occurences we keep for each
// term. The abstract has a finite length anyway !
if (occurrences++ > 10)
break;
}
} catch (...) {
}
}
LOGDEB1(("Abstract:%d:chosen number of positions %d. Populating\n",
chron.millis(), qtermposs.size()));
// Walk the full document position list and populate slots around
// the query terms. We arbitrarily truncate the list to avoid
// taking forever. If we do cutoff, the abstract may be
// inconsistant, which is bad...
{ Xapian::TermIterator term;
int cutoff = 500 * 1000;
for (term = db.termlist_begin(docid);
term != db.termlist_end(docid); term++) {
Xapian::PositionIterator pos;
for (pos = db.positionlist_begin(docid, *term);
pos != db.positionlist_end(docid, *term); pos++) {
if (cutoff-- < 0)
break;
unsigned int ipos = *pos;
if (chunkposs.find(ipos) != chunkposs.end()) {
buf[ipos] = *term;
}
}
if (cutoff-- < 0)
break;
}
}
LOGDEB1(("Abstract:%d: randomizing and extracting\n", chron.millis()));
// We randomize the selection of term positions, from which we
// shall pull, starting at the beginning, until the abstract is
// big enough. The abstract is finally built in correct position
// order, thanks to the position map.
random_shuffle(qtermposs.begin(), qtermposs.end());
map<unsigned int, string> mabs;
unsigned int abslen = 0;
LOGDEB1(("Abstract:%d: extracting\n", chron.millis()));
// Extract data around the first (in random order) term positions,
// and store the chunks in the map
for (vector<unsigned int>::const_iterator it = qtermposs.begin();
it != qtermposs.end(); it++) {
unsigned int ipos = *it;
unsigned int start = MAX(0, ipos-MA_EXTRACT_WIDTH);
unsigned int end = MIN(ipos+MA_EXTRACT_WIDTH, buf.size()-1);
string chunk;
for (unsigned int ii = start; ii <= end; ii++) {
if (!buf[ii].empty()) {
chunk += buf[ii] + " ";
abslen += buf[ii].length();
}
if (abslen > MA_ABSTRACT_SIZE)
break;
}
if (end != buf.size()-1)
chunk += "... ";
mabs[ipos] = chunk;
if (abslen > MA_ABSTRACT_SIZE)
break;
}
// Build the abstract by walking the map (in order of position)
string abstract;
for (map<unsigned int, string>::const_iterator it = mabs.begin();
it != mabs.end(); it++) {
abstract += (*it).second;
}
LOGDEB(("Abtract: done in %d mS\n", chron.millis()));
return abstract;
}
#ifndef NO_NAMESPACES
}
#endif