/* Copyright (c) 2001-2019, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */


package org.hsqldb;

import org.hsqldb.error.Error;
import org.hsqldb.error.ErrorCode;
import org.hsqldb.lib.StringConverter;
import org.hsqldb.persist.PersistentStore;
import org.hsqldb.persist.TextCache;
import org.hsqldb.persist.TextFileReader;
import org.hsqldb.rowio.RowInputInterface;

Subclass of Table to handle TEXT data source. 

Extends Table to provide the notion of an SQL base table object whose
data is read from and written to a text format data file.
Author:
Bob Preston (sqlbob@users dot sourceforge.net), Fred Toussi (fredt@users dot sourceforge.net)
Version:
2.4.1/**
 * Subclass of Table to handle TEXT data source. <p>
 *
 * Extends Table to provide the notion of an SQL base table object whose
 * data is read from and written to a text format data file.
 *
 * @author Bob Preston (sqlbob@users dot sourceforge.net)
 * @author Fred Toussi (fredt@users dot sourceforge.net)
 * @version 2.4.1
 */
public class TextTable extends Table {

    String  dataSource  = "";
    boolean isReversed  = false;
    boolean isConnected = false;

//    TextCache cache;

    
Constructs a new TextTable from the given arguments.
Params:
db – the owning database
name – the table's HsqlName
type – code (normal or temp text table)/**
     * Constructs a new TextTable from the given arguments.
     *
     * @param db the owning database
     * @param name the table's HsqlName
     * @param type code (normal or temp text table)
     */
    TextTable(Database db, HsqlNameManager.HsqlName name, int type) {

        super(db, name, type);

        isWithDataSource = true;
    }

    public boolean isConnected() {
        return isConnected;
    }

    
connects to the data source
/**
     * connects to the data source
     */
    public void connect(Session session) {
        connect(session, isReadOnly);
    }

    
connects to the data source
/**
     * connects to the data source
     */
    private void connect(Session session, boolean withReadOnlyData) {

        // Open new cache:
        if ((dataSource.length() == 0) || isConnected) {

            // nothing to do
            return;
        }

        store = database.persistentStoreCollection.getStore(this);

        TextCache      cache    = null;
        TextFileReader reader   = null;
        boolean        readOnly = isReadOnly || database.isReadOnly();
        String securePath = database.logger.getSecurePath(dataSource, false,
            true);

        if (securePath == null) {
            throw (Error.error(ErrorCode.ACCESS_IS_DENIED, dataSource));
        }

        try {
            cache =
                (TextCache) database.logger.textTableManager
                    .openTextFilePersistence(this, securePath, readOnly,
                                             isReversed);

            store.setCache(cache);

            reader = cache.getTextFileReader();

            // read and insert all the rows from the source file
            if (cache.isIgnoreFirstLine()) {
                reader.readHeaderLine();
                cache.setHeaderInitialise(reader.getHeaderLine());
            }

            readDataIntoTable(session, store, reader);
        } catch (Throwable t) {
            long linenumber = reader == null ? 0
                                             : reader.getLineNumber();

            store.removeAll();

            if (identitySequence != null) {
                identitySequence.reset();
            }

            if (cache != null) {
                database.logger.textTableManager.closeTextCache(this);
                store.release();
            }

            // everything is in order here.
            // At this point table should either have a valid (old) data
            // source and cache or have an empty source and null cache.
            throw Error.error(t, ErrorCode.TEXT_FILE, 0, new Object[] {
                Long.valueOf(linenumber), t.toString()
            });
        }

        isConnected = true;
        isReadOnly  = withReadOnlyData;
    }

    private void readDataIntoTable(Session session, PersistentStore store,
                                   TextFileReader reader) {

        while (true) {
            RowInputInterface rowIn = reader.readObject();

            if (rowIn == null) {
                break;
            }

            Row row = (Row) store.get(rowIn);

            if (row == null) {
                break;
            }

            Object[] data = row.getData();

            systemUpdateIdentityValue(data);
            enforceRowConstraints(session, data);
            store.indexRow(session, row);
        }
    }

    
disconnects from the data source
/**
     * disconnects from the data source
     */
    public void disconnect() {

        this.store = null;

        PersistentStore store =
            database.persistentStoreCollection.getStore(this);

        store.release();

        isConnected = false;
    }

    
This method does some of the work involved with managing the creation
and opening of the cache, the rest is done in Log.java and
TextCache.java.
Better clarification of the role of the methods is needed.
/**
     * This method does some of the work involved with managing the creation
     * and opening of the cache, the rest is done in Log.java and
     * TextCache.java.
     *
     * Better clarification of the role of the methods is needed.
     */
    private void openCache(Session session, String dataSourceNew,
                           boolean isReversedNew, boolean isReadOnlyNew) {

        String  dataSourceOld = dataSource;
        boolean isReversedOld = isReversed;
        boolean isReadOnlyOld = isReadOnly;

        if (dataSourceNew == null) {
            dataSourceNew = "";
        }

        disconnect();

        dataSource = dataSourceNew;
        isReversed = (isReversedNew && dataSource.length() > 0);

        try {
            connect(session, isReadOnlyNew || isReversedNew);
        } catch (HsqlException e) {
            dataSource = dataSourceOld;
            isReversed = isReversedOld;

            connect(session, isReadOnlyOld);

            throw e;
        }
    }

    
High level command to assign a data source to the table definition.
Reassigns only if the data source or direction has changed.
/**
     * High level command to assign a data source to the table definition.
     * Reassigns only if the data source or direction has changed.
     */
    void setDataSource(Session session, String dataSourceNew,
                       boolean isReversedNew, boolean createFile) {

        if (getTableType() == Table.TEMP_TEXT_TABLE) {

            //
        } else {
            session.getGrantee().checkSchemaUpdateOrGrantRights(
                getSchemaName().name);
        }

        dataSourceNew = dataSourceNew.trim();

        //-- Open if descending, direction changed, file changed, or not connected currently
        if (isReversedNew || (isReversedNew != isReversed)
                || !dataSource.equals(dataSourceNew) || !isConnected) {
            openCache(session, dataSourceNew, isReversedNew, isReadOnly);
        }

        if (isReversed) {
            isReadOnly = true;
        }
    }

    public String getDataSource() {
        return dataSource;
    }

    public boolean isDescDataSource() {
        return isReversed;
    }

    public void setHeader(String header) {

        PersistentStore store =
            database.persistentStoreCollection.getStore(this);
        TextCache cache = (TextCache) store.getCache();

        if (cache != null && cache.isIgnoreFirstLine()) {
            cache.setHeader(header);

            return;
        }

        throw Error.error(ErrorCode.TEXT_TABLE_HEADER);
    }

    private String getHeader() {

        PersistentStore store =
            database.persistentStoreCollection.getStore(this);
        TextCache cache  = (TextCache) store.getCache();
        String    header = cache == null ? null
                                         : cache.getHeader();

        return header == null ? null
                              : StringConverter.toQuotedString(header, '\'',
                              true);
    }

    
Used by INSERT, DELETE, UPDATE operations. This class will return
a more appropriate message when there is no data source.
/**
     * Used by INSERT, DELETE, UPDATE operations. This class will return
     * a more appropriate message when there is no data source.
     */
    public void checkDataReadOnly() {

        if (dataSource.length() == 0) {
            String name = getName().getSchemaQualifiedStatementName();

            throw Error.error(ErrorCode.TEXT_TABLE_UNKNOWN_DATA_SOURCE, name);
        }

        if (isDataReadOnly()) {
            throw Error.error(ErrorCode.DATA_IS_READONLY);
        }
    }

    public boolean isDataReadOnly() {
        return !isConnected() || super.isDataReadOnly()
               || store.getCache().isDataReadOnly();
    }

    public void setDataReadOnly(boolean value) {

        if (!value) {
            if (isReversed) {
                throw Error.error(ErrorCode.DATA_IS_READONLY);
            }

            if (database.isFilesReadOnly()) {
                throw Error.error(ErrorCode.DATABASE_IS_READONLY);
            }

            if (isConnected()) {
                store.getCache().close();
                store.getCache().open(value);
            }
        }

        isReadOnly = value;
    }

    
Adds commitPersistence() call
/**
     * Adds commitPersistence() call
     */
    public void insertData(Session session, PersistentStore store,
                           Object[] data, boolean enforceUnique) {

        Row row = (Row) store.getNewCachedObject(session, data, false);

        store.indexRow(session, row);
        store.commitPersistence(row);
    }

    String getDataSourceDDL() {

        String dataSource = getDataSource();

        if (dataSource == null) {
            return null;
        }

        StringBuilder sb = new StringBuilder(128);

        sb.append(Tokens.T_SET).append(' ').append(Tokens.T_TABLE).append(' ');
        sb.append(getName().getSchemaQualifiedStatementName());
        sb.append(' ').append(Tokens.T_SOURCE).append(' ').append('\'');
        sb.append(dataSource);
        sb.append('\'');

        return sb.toString();
    }

    
Generates the SET TABLE  SOURCE HEADER  statement for a
text table;
/**
     * Generates the SET TABLE <tablename> SOURCE HEADER <string> statement for a
     * text table;
     */
    String getDataSourceHeader() {

        String header = getHeader();

        if (header == null) {
            return null;
        }

        StringBuilder sb = new StringBuilder(128);

        sb.append(Tokens.T_SET).append(' ').append(Tokens.T_TABLE).append(' ');
        sb.append(getName().getSchemaQualifiedStatementName());
        sb.append(' ').append(Tokens.T_SOURCE).append(' ');
        sb.append(Tokens.T_HEADER).append(' ');
        sb.append(header);

        return sb.toString();
    }
}