corpus.cpp

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/*
  Phrasehunter - index and query text corpora
  Copyright (C) 2006  Torsten Marek (shlomme@gmx.de) &
  Armin Schmidt (armin.sch@gmail.com)
  
  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 Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

#include <iostream>
#include <boost/filesystem/operations.hpp>
#include <boost/format.hpp>
#include <boost/lexical_cast.hpp>

#include "sqlitepp/sqlitepp.h"

#include "phrasehunter/corpus.h"
#include "phrasehunter/indexer.h"
#include "phrasehunter/tokenizer.h"
#include "phrasehunter/searchengine.h"
#include "phrasehunter/statistics.h"
#include "phrasehunter/contextreader.h"


using boost::lexical_cast;
using namespace SQLitePP;
namespace filesystem = boost::filesystem;

namespace PhraseHunter {

const int CorpusManager::Repository::Format = 4;
const std::string CorpusManager::Repository::TextDirectory("texts");
const std::string CorpusManager::Repository::InfoFile("info");
const std::string CorpusManager::Repository::IndexFile((boost::format("index-%||.db") % Format).str());

CorpusManager::CorpusManager(const std::string& corpus_repository, CorpusManager::Mode mode)
    throw(Exceptions::NoSuchCorpusError)
    : m_mode(mode), 
      m_directory(corpus_repository),
      m_searchEngine(NULL),
      m_statistics(NULL),
      m_contextReader(NULL),
      m_db(indexFile().string())
{
    if(!filesystem::exists(textDir().string()) || !filesystem::exists(indexFile().string()))
        throw Exceptions::NoSuchCorpusError(corpus_repository);

    m_indexer = (mode & Write) ? new IndexManager(m_db) : NULL;
}

CorpusManager::~CorpusManager()
{
    // it's safe to call delete on a NULL pointer
    delete m_indexer;
    delete m_searchEngine;
    delete m_statistics;
}

SearchEngine* CorpusManager::searchEngine()
{
    if(m_searchEngine == NULL) {
        m_searchEngine = new SearchEngine(m_db);
    }
    return m_searchEngine;
}

StatisticsEngine* CorpusManager::statisticsEngine()
{
    if(m_statistics == NULL) {
        m_statistics = new StatisticsEngine(searchEngine(), contextReader(), m_db);
    }
    return m_statistics;
}

ContextReader* CorpusManager::contextReader()    
{
    if(m_contextReader == NULL) {
        m_contextReader = new ContextReader(textDir());
    }
    return m_contextReader;
}

std::string CorpusManager::documentName(DocID docID)
{
    Statement::Pointer dn = m_db.statement("select description from docs where docid = ?");
    
    ResultIterator ri = (*dn)
        .bindArgs(docID)
        .query();
    
    return (ri.hasMoreRows()) 
        ? ri.get<std::string>(0)
        : "";
}

    
void CorpusManager::addFile(const std::string& filename, const std::string& info)
    throw (Exceptions::FileError, Exceptions::NoIndexerError, std::out_of_range)
{
    if (m_indexer == NULL)
        throw Exceptions::NoIndexerError();
    

    
    int newDocID = 
        (*m_db.statement("INSERT INTO docs (description) VALUES (?)"))
        .bindArgs(info)
        .exec()
        .lastInsertId();
    
    filesystem::path newname = textDir() / lexical_cast<std::string>(newDocID);
    
    (*m_db.statement("UPDATE docs SET filename = ? WHERE id = ?"))
        .bindArgs(newname.string(), newDocID)
        .exec();
    
    TextSaver ts(filename, newname.string());
    m_indexer->addToIndex(ts, newDocID);
}

void CorpusManager::removeFile(DocID docID) throw (Exceptions::NoIndexerError)
{
    if(m_indexer == NULL)
        throw Exceptions::NoIndexerError();
    filesystem::remove(textDir() / lexical_cast<std::string>(docID));
    
    (*m_db.statement("DELETE FROM docs WHERE docid = ?"))
        .bindArgs(docID)
        .exec();
    
    m_indexer->removeFromIndex(docID);
}

}

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