/// Flushes recent changes to the disk.
bool XapianIndex::flush(void)
{
	bool flushed = false;

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
#ifdef DEBUG
		cout << "XapianIndex::flush: called" << endl;
#endif
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			pIndex->flush();
			flushed = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't flush database: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't flush database, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return flushed;
}

/// Renames a label.
bool XapianIndex::renameLabel(const string &name, const string &newName)
{
	bool renamedLabel = false;

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			string term("XLABEL:");

			// Get documents that have this label
			term += name;
			for (Xapian::PostingIterator postingIter = pIndex->postlist_begin(term);
				postingIter != pIndex->postlist_end(term); ++postingIter)
			{
				Xapian::docid docId = *postingIter;

				// Get the document
				Xapian::Document doc = pIndex->get_document(docId);
				// Remove the term
				doc.remove_term(term);
				// ...add the new one
				doc.add_term(limitTermLength(string("XLABEL:") + newName));
				// ...and update the document
				pIndex->replace_document(docId, doc);
			}

			renamedLabel = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't delete label: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't delete label, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return renamedLabel;
}

/// Updates a document's properties.
bool XapianIndex::updateDocumentInfo(unsigned int docId, const DocumentInfo &docInfo)
{
	bool updated = false;

	if (docId == 0)
	{
		return false;
	}

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			Xapian::Document doc = pIndex->get_document(docId);
			Xapian::termcount termPos = 0;

			// Update the document data with the current language
			removeCommonTerms(doc);
			m_stemLanguage = Languages::toEnglish(docInfo.getLanguage());
			addCommonTerms(docInfo, doc, termPos);
			setDocumentData(docInfo, doc, m_stemLanguage);

			pIndex->replace_document(docId, doc);
			updated = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't update document properties: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't update document properties, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return updated;
}

/// Determines whether a document has a label.
bool XapianIndex::hasLabel(unsigned int docId, const string &name) const
{
	bool foundLabel = false;

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			string term("XLABEL:");

			// Get documents that have this label
			// FIXME: would it be faster to get the document's terms ?
			term += name;
			Xapian::PostingIterator postingIter = pIndex->postlist_begin(term);
			if (postingIter != pIndex->postlist_end(term))
			{
				// Is this document in the list ?
				postingIter.skip_to(docId);
				if ((postingIter != pIndex->postlist_end(term)) &&
					(docId == (*postingIter)))
				{
					foundLabel = true;
				}
			}
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't check document labels: " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't check document labels, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return foundLabel;
}

/// Updates a document's properties.
bool XapianIndex::updateDocumentInfo(unsigned int docId, const DocumentInfo &docInfo)
{
	bool updated = false;

	if (docId == 0)
	{
		return false;
	}

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			Xapian::Document doc = pIndex->get_document(docId);

#ifdef DEBUG
			cout << "XapianIndex::updateDocumentInfo: language is " << docInfo.getLanguage() << endl;
#endif
			// Update the document data with the current language
			setDocumentData(doc, docInfo, docInfo.getLanguage());
			pIndex->replace_document(docId, doc);
			updated = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't update document properties: " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't update document properties, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return updated;
}

bool XapianIndex::deleteDocuments(const string &term)
{
    bool unindexed = false;

    if (term.empty() == true)
    {
        return false;
    }

    XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
    if (pDatabase == NULL)
    {
        cerr << "Bad index " << m_databaseName << endl;
        return false;
    }

    try
    {
        Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
        if (pIndex != NULL)
        {
#ifdef DEBUG
            cout << "XapianIndex::deleteDocuments: term is " << term << endl;
#endif

            // Delete documents from the index
            pIndex->delete_document(term);

            unindexed = true;
        }
    }
    catch (const Xapian::Error &error)
    {
        cerr << "Couldn't unindex documents: " << error.get_type() << ": " << error.get_msg() << endl;
    }
    catch (...)
    {
        cerr << "Couldn't unindex documents, unknown exception occured" << endl;
    }
    pDatabase->unlock();

    return unindexed;
}

/// Unindexes documents with the given label.
bool XapianIndex::unindexDocuments(const string &labelName)
{
	bool unindexed = false;

	if (labelName.empty() == true)
	{
		return false;
	}

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			string term("XLABEL:");

			// Delete documents from the index
			term += labelName;
			pIndex->delete_document(term);
			unindexed = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't unindex documents: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't unindex documents, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return unindexed;
}

/// Unindexes the given document; true if success.
bool XapianIndex::unindexDocument(unsigned int docId)
{
	bool unindexed = false;

	if (docId == 0)
	{
		return false;
	}

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			// Delete the document from the index
			pIndex->delete_document(docId);
			unindexed = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't unindex document: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't unindex document, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return unindexed;
}

/// Indexes the given data.
bool XapianIndex::indexDocument(Tokenizer &tokens, const std::set<std::string> &labels,
	unsigned int &docId)
{
	unsigned int dataLength = 0;
	bool indexed = false;

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		// Get the document
		const Document *pDocument = tokens.getDocument();
		if (pDocument == NULL)
		{
#ifdef DEBUG
			cout << "XapianIndex::indexDocument: no document" << endl;
#endif
			return false;
		}

		// Cache the document's properties
		DocumentInfo docInfo(pDocument->getTitle(), pDocument->getLocation(),
			pDocument->getType(), pDocument->getLanguage());
		docInfo.setTimestamp(pDocument->getTimestamp());
		docInfo.setLocation(Url::canonicalizeUrl(docInfo.getLocation()));

		const char *pData = pDocument->getData(dataLength);
		if (pData != NULL)
		{
			m_stemLanguage = scanDocument(pData, dataLength, docInfo);
		}

		Xapian::Document doc;
		Xapian::termcount termPos = 0;

#ifdef DEBUG
		cout << "XapianIndex::indexDocument: adding terms" << endl;
#endif
		// Add the tokenizer's terms to the Xapian document
		addPostingsToDocument(tokens, doc, "", termPos, m_stemMode);
		// Add labels
		for (set<string>::const_iterator labelIter = labels.begin(); labelIter != labels.end();
			++labelIter)
		{
			doc.add_term(limitTermLength(string("XLABEL:") + *labelIter));
		}
		if (addCommonTerms(docInfo, doc, termPos) == true)
		{
			setDocumentData(docInfo, doc, m_stemLanguage);

			Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
			if (pIndex != NULL)
			{
				// Add this document to the Xapian index
				docId = pIndex->add_document(doc);
				indexed = true;
			}
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't index document: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't index document, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return indexed;
}

/// Sets a document's labels.
bool XapianIndex::setDocumentLabels(unsigned int docId, const set<string> &labels,
	bool resetLabels)
{
	bool updatedLabels = false;

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	try
	{
		Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
		if (pIndex != NULL)
		{
			Xapian::Document doc = pIndex->get_document(docId);

			// Reset existing labels ?
			if (resetLabels == true)
			{
				Xapian::TermIterator termIter = pIndex->termlist_begin(docId);
				if (termIter != pIndex->termlist_end(docId))
				{
					for (termIter.skip_to("XLABEL:");
						termIter != pIndex->termlist_end(docId); ++termIter)
					{
						// Is this a label ?
						if (strncasecmp((*termIter).c_str(), "XLABEL:", min(7, (int)(*termIter).length())) == 0)
						{
							doc.remove_term(*termIter);
						}
					}
				}
			}

			// Set new labels
			for (set<string>::const_iterator labelIter = labels.begin(); labelIter != labels.end();
				++labelIter)
			{
				if (labelIter->empty() == false)
				{
					doc.add_term(limitTermLength(string("XLABEL:") + *labelIter));
				}
			}

			pIndex->replace_document(docId, doc);
			updatedLabels = true;
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't update document's labels: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't update document's labels, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return updatedLabels;
}

/// Updates the given document; true if success.
bool XapianIndex::updateDocument(unsigned int docId, Tokenizer &tokens)
{
	unsigned int dataLength = 0;
	bool updated = false;

	const Document *pDocument = tokens.getDocument();
	if (pDocument == NULL)
	{
		return false;
	}

	XapianDatabase *pDatabase = XapianDatabaseFactory::getDatabase(m_databaseName, false);
	if (pDatabase == NULL)
	{
		cerr << "Bad index " << m_databaseName << endl;
		return false;
	}

	const char *pData = pDocument->getData(dataLength);
	if (pData == NULL)
	{
		return false;
	}

	// Cache the document's properties
	DocumentInfo docInfo(pDocument->getTitle(), pDocument->getLocation(),
		pDocument->getType(), pDocument->getLanguage());
	docInfo.setTimestamp(pDocument->getTimestamp());
	docInfo.setLocation(Url::canonicalizeUrl(docInfo.getLocation()));

	// Don't scan the document if a language is specified
	m_stemLanguage = Languages::toEnglish(pDocument->getLanguage());
	if (m_stemLanguage.empty() == true)
	{
		m_stemLanguage = scanDocument(pData, dataLength, docInfo);
	}

	try
	{
		set<string> labels;
		Xapian::Document doc;
		Xapian::termcount termPos = 0;

		// Add the tokenizer's terms to the document
		addPostingsToDocument(tokens, doc, "", termPos, m_stemMode);
		// Get the document's labels
		if (getDocumentLabels(docId, labels) == true)
		{
			// Add labels
			for (set<string>::const_iterator labelIter = labels.begin(); labelIter != labels.end();
				++labelIter)
			{
				doc.add_term(limitTermLength(string("XLABEL:") + *labelIter));
			}
		}
		if (addCommonTerms(docInfo, doc, termPos) == true)
		{
			setDocumentData(docInfo, doc, m_stemLanguage);

			Xapian::WritableDatabase *pIndex = pDatabase->writeLock();
			if (pIndex != NULL)
			{
				// Update the document in the database
				pIndex->replace_document(docId, doc);
				updated = true;
			}
		}
	}
	catch (const Xapian::Error &error)
	{
		cerr << "Couldn't update document: " << error.get_type() << ": " << error.get_msg() << endl;
	}
	catch (...)
	{
		cerr << "Couldn't update document, unknown exception occured" << endl;
	}
	pDatabase->unlock();

	return updated;
}

bool
DatabaseWrite::rebuild (GList *cpt_list)
{
	string old_path = m_dbPath + "_old";
	string rebuild_path = m_dbPath + "_rb";
	string db_locale;

	// Create the rebuild directory
	if (g_mkdir_with_parents (rebuild_path.c_str (), 0755) != 0) {
		g_warning ("Unable to create database rebuild directory.");
		return false;
	}

	// check if old unrequired version of db still exists on filesystem
	if (g_file_test (old_path.c_str (), G_FILE_TEST_EXISTS)) {
		g_warning ("Existing xapian old db was not cleaned previously: '%s'.", old_path.c_str ());
		as_utils_delete_dir_recursive (old_path.c_str ());
	}

	// check if old unrequired version of db still exists on filesystem
	if (g_file_test (rebuild_path.c_str (), G_FILE_TEST_EXISTS)) {
		g_debug ("Removing old rebuild-dir from previous database rebuild.");
		as_utils_delete_dir_recursive (rebuild_path.c_str ());
	}

	Xapian::WritableDatabase db (rebuild_path, Xapian::DB_CREATE_OR_OVERWRITE);

	Xapian::TermGenerator term_generator;
	term_generator.set_database(db);
	try {
		/* this tests if we have spelling suggestions (there must be
		 * a better way?!?) - this is needed as inmemory does not have
		 * spelling corrections, but it allows setting the flag and will
		 * raise a exception much later
		 */
		db.add_spelling("test");
		db.remove_spelling("test");

		/* this enables the flag for it (we only reach this line if
		 * the db supports spelling suggestions)
		 */
		term_generator.set_flags(Xapian::TermGenerator::FLAG_SPELLING);
	} catch (const Xapian::UnimplementedError &error) {
		// Ignore
	}

	for (GList *list = cpt_list; list != NULL; list = list->next) {
		AsComponent *cpt = (AsComponent*) list->data;

		Xapian::Document doc;
		term_generator.set_document (doc);

		doc.set_data (as_component_get_name (cpt));

		// Sanity check
		if (!as_component_has_install_candidate (cpt)) {
			g_warning ("Skipped component '%s' from inclusion into database: Does not have an installation candidate.",
					   as_component_get_id (cpt));
			continue;
		}

		// Package name
		gchar **pkgs = as_component_get_pkgnames (cpt);
		if (pkgs != NULL) {
			gchar *pkgs_cstr = g_strjoinv (";", pkgs);
			string pkgs_str = pkgs_cstr;
			doc.add_value (XapianValues::PKGNAMES, pkgs_str);
			g_free (pkgs_cstr);

			for (uint i = 0; pkgs[i] != NULL; i++) {
				string pkgname = pkgs[i];
				doc.add_term("AP" + pkgname);
				if (pkgname.find ("-") != string::npos) {
					// we need this to work around xapian oddness
					string tmp = pkgname;
					replace (tmp.begin (), tmp.end (), '-', '_');
					doc.add_term (tmp);
				}
				// add packagename as meta-data too
				term_generator.index_text_without_positions (pkgname, WEIGHT_PKGNAME);
			}
		}

		// Source package name
		const gchar *spkgname_cstr = as_component_get_source_pkgname (cpt);
		if (spkgname_cstr != NULL) {
			string spkgname = spkgname_cstr;
			doc.add_value (XapianValues::SOURCE_PKGNAME, spkgname);
			if (!spkgname.empty()) {
				doc.add_term("AP" + spkgname);
				if (spkgname.find ("-") != string::npos) {
					// we need this to work around xapian oddness
					string tmp = spkgname;
					replace (tmp.begin (), tmp.end (), '-', '_');
					doc.add_term (tmp);
				}
				// add packagename as meta-data too
				term_generator.index_text_without_positions (spkgname, WEIGHT_PKGNAME);
			}
		}
//.........这里部分代码省略.........