cursor.cpp

/* This file is part of the KDE project
   Copyright (C) 2003-2006 Jaroslaw Staniek <js@iidea.pl>
 
   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library 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
   Library General Public License for more details.
 
   You should have received a copy of the GNU Library General Public License
   along with this program; see the file COPYING.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
*/
 
#include <kexidb/cursor.h>
 
#include <kexidb/driver.h>
#include <kexidb/driver_p.h>
#include <kexidb/error.h>
#include <kexidb/roweditbuffer.h>
#include <kexiutils/utils.h>
 
#include <kdebug.h>
#include <tdelocale.h>
 
#include <assert.h>
#include <stdlib.h>
 
using namespace KexiDB;
 
#ifdef KEXI_DEBUG_GUI
 
#endif
 
Cursor::Cursor(Connection* conn, const TQString& statement, uint options)
    : TQObject()
    , m_conn(conn)
    , m_query(0)
    , m_rawStatement(statement)
    , m_options(options)
{
#ifdef KEXI_DEBUG_GUI
    KexiUtils::addKexiDBDebug(TQString("Create cursor: ")+statement);
#endif
    init();
}
 
Cursor::Cursor(Connection* conn, QuerySchema& query, uint options )
    : TQObject()
    , m_conn(conn)
    , m_query(&query)
    , m_options(options)
{
#ifdef KEXI_DEBUG_GUI
    KexiUtils::addKexiDBDebug(TQString("Create cursor for query \"%1\": ").arg(query.name())+query.debugString());
#endif
    init();
}
 
void Cursor::init()
{
    assert(m_conn);
    m_conn->m_cursors.insert(this,this);
    m_opened = false;
//  , m_atFirst(false)
//  , m_atLast(false)
//  , m_beforeFirst(false)
    m_atLast = false;
    m_afterLast = false;
    m_readAhead = false;
    m_at = 0;
//js:todo:  if (m_query)
//      m_fieldCount = m_query->fieldsCount();
//  m_fieldCount = m_query ? m_query->fieldCount() : 0; //do not know
    //<members related to buffering>
//  m_cols_pointers_mem_size = 0;
    m_records_in_buf = 0;
    m_buffering_completed = false;
    m_at_buffer = false;
    m_result = -1;
 
    m_containsROWIDInfo = (m_query && m_query->masterTable()) 
        && m_conn->driver()->beh->ROW_ID_FIELD_RETURNS_LAST_AUTOINCREMENTED_VALUE == false;
 
    if (m_query) {
        //get list of all fields
        m_fieldsExpanded = new QueryColumnInfo::Vector();
        *m_fieldsExpanded = m_query->fieldsExpanded(
            m_containsROWIDInfo ? QuerySchema::WithInternalFieldsAndRowID : QuerySchema::WithInternalFields);
        m_logicalFieldCount = m_fieldsExpanded->count() 
            - m_query->internalFields().count() - (m_containsROWIDInfo?1:0);
        m_fieldCount = m_fieldsExpanded->count();
    } else {
        m_fieldsExpanded = 0;
        m_logicalFieldCount = 0;
        m_fieldCount = 0;
    }
    m_orderByColumnList = 0;
    m_queryParameters = 0;
}
 
Cursor::~Cursor()
{
#ifdef KEXI_DEBUG_GUI
    if (m_query)
        KexiUtils::addKexiDBDebug(TQString("~ Delete cursor for query"));
    else
        KexiUtils::addKexiDBDebug(TQString("~ Delete cursor: ")+m_rawStatement);
#endif
/*  if (!m_query)
        KexiDBDbg << "Cursor::~Cursor() '" << m_rawStatement.latin1() << "'" << endl;
    else
        KexiDBDbg << "Cursor::~Cursor() " << endl;*/
 
    //take me if delete was 
    if (!m_conn->m_destructor_started)
        m_conn->m_cursors.take(this);
    else {
        KexiDBDbg << "Cursor::~Cursor() can be destroyed with Conenction::deleteCursor(), not with delete operator !"<< endl;
        exit(1);
    }
    delete m_fieldsExpanded;
    delete m_queryParameters;
}
 
bool Cursor::open()
{
    if (m_opened) {
        if (!close())
            return false;
    }
    if (!m_rawStatement.isEmpty())
        m_conn->m_sql = m_rawStatement;
    else {
        if (!m_query) {
            KexiDBDbg << "Cursor::open(): no query statement (or schema) defined!" << endl;
            setError(ERR_SQL_EXECUTION_ERROR, i18n("No query statement or schema defined."));
            return false;
        }
        Connection::SelectStatementOptions options;
        options.alsoRetrieveROWID = m_containsROWIDInfo; /*get ROWID if needed*/
        m_conn->m_sql = m_queryParameters 
            ? m_conn->selectStatement( *m_query, *m_queryParameters, options )
            : m_conn->selectStatement( *m_query, options );
        if (m_conn->m_sql.isEmpty()) {
            KexiDBDbg << "Cursor::open(): empty statement!" << endl;
            setError(ERR_SQL_EXECUTION_ERROR, i18n("Query statement is empty."));
            return false;
        }
    }
    m_sql = m_conn->m_sql;
    m_opened = drv_open();
//  m_beforeFirst = true;
    m_afterLast = false; //we are not @ the end
    m_at = 0; //we are before 1st rec
    if (!m_opened) {
        setError(ERR_SQL_EXECUTION_ERROR, i18n("Error opening database cursor."));
        return false;
    }
    m_validRecord = false;
 
//luci: WHAT_EXACTLY_SHOULD_THAT_BE?
//  if (!m_readAhead) // jowenn: to ensure before first state, without cluttering implementation code
    if (m_conn->driver()->beh->_1ST_ROW_READ_AHEAD_REQUIRED_TO_KNOW_IF_THE_RESULT_IS_EMPTY) {
//      KexiDBDbg << "READ AHEAD:" << endl;
        m_readAhead = getNextRecord(); //true if any record in this query
//      KexiDBDbg << "READ AHEAD = " << m_readAhead << endl;
    }
    m_at = 0; //we are still before 1st rec
    return !error();
}
 
bool Cursor::close()
{
    if (!m_opened)
        return true;
    bool ret = drv_close();
 
    clearBuffer();
 
    m_opened = false;
//  m_beforeFirst = false;
    m_afterLast = false;
    m_readAhead = false;
    m_fieldCount = 0;
    m_logicalFieldCount = 0;
    m_at = -1;
 
//  KexiDBDbg<<"Cursor::close() == "<<ret<<endl;
    return ret;
}
 
bool Cursor::reopen()
{
    if (!m_opened)
        return open();
    return close() && open();
}
 
bool Cursor::moveFirst()
{
    if (!m_opened)
        return false;
//  if (!m_beforeFirst) { //cursor isn't @ first record now: reopen
    if (!m_readAhead) {
        if (m_options & Buffered) {
            if (m_records_in_buf==0 && m_buffering_completed) {
                //eof and bof should now return true:
                m_afterLast = true;
                m_at = 0;
                return false; //buffering completed and there is no records!
            }
            if (m_records_in_buf>0) {
                //set state as we would be before first rec:
                m_at_buffer = false;
                m_at = 0;
                //..and move to next, ie. 1st record
//              m_afterLast = m_afterLast = !getNextRecord();
                m_afterLast = !getNextRecord();
                return !m_afterLast;
            }
        }
        if (m_afterLast && m_at==0) //failure if already no records
            return false;
        if (!reopen()) //try reopen
            return false;
        if (m_afterLast) //eof
            return false;
    }
    else {
        //we have a record already read-ahead: we now point @ that:
        m_at = 1;
    }
//  if (!m_atFirst) { //cursor isn't @ first record now: reopen
//      reopen();
//  }
//  if (m_validRecord) {
//      return true; //there is already valid record retrieved
//  }
    //get first record
//  if (drv_moveFirst() && drv_getRecord()) {
//      m_beforeFirst = false;
        m_afterLast = false;
        m_readAhead = false; //1st record had been read
//  }
    return m_validRecord;
}
 
bool Cursor::moveLast()
{
    if (!m_opened)
        return false;
    if (m_afterLast || m_atLast) {
        return m_validRecord; //we already have valid last record retrieved
    }
    if (!getNextRecord()) { //at least next record must be retrieved
//      m_beforeFirst = false;
        m_afterLast = true;
        m_validRecord = false;
        m_atLast = false;
        return false; //no records
    }
    while (getNextRecord()) //move after last rec.
        ;
//  m_beforeFirst = false;
    m_afterLast = false;
    //cursor shows last record data
    m_atLast = true; 
//  m_validRecord = true;
 
/*
    //we are before or @ last record:
//  if (m_atLast && m_validRecord) //we're already @ last rec.
//      return true;
    if (m_validRecord) {
        if (drv_getRecord())
    }
    if (!m_validRecord) {
        if (drv_getRecord() && m_validRecord)
            return true;
        reopen();
    }
    */
    return true;
}
 
bool Cursor::moveNext()
{
    if (!m_opened || m_afterLast)
        return false;
    if (getNextRecord()) {
//      m_validRecord = true;
        return true;
    }
    return false;
}
 
bool Cursor::movePrev()
{
    if (!m_opened /*|| m_beforeFirst*/ || !(m_options & Buffered))
        return false;
 
    //we're after last record and there are records in the buffer
    //--let's move to last record
    if (m_afterLast && (m_records_in_buf>0)) {
        drv_bufferMovePointerTo(m_records_in_buf-1);
        m_at=m_records_in_buf;
        m_at_buffer = true; //now current record is stored in the buffer
        m_validRecord=true;
        m_afterLast=false;
        return true;
    }
    //we're at first record: go BOF
    if ((m_at <= 1) || (m_records_in_buf <= 1/*sanity*/)) {
        m_at=0;
        m_at_buffer = false;
        m_validRecord=false;
        return false;
    }
 
    m_at--;
    if (m_at_buffer) {//we already have got a pointer to buffer
        drv_bufferMovePointerPrev(); //just move to prev record in the buffer
    } else {//we have no pointer
        //compute a place in the buffer that contain next record's data
        drv_bufferMovePointerTo(m_at-1);
        m_at_buffer = true; //now current record is stored in the buffer
    }
    m_validRecord=true;
    m_afterLast=false;
    return true;
}
 
bool Cursor::eof() const
{
    return m_afterLast;
}
 
bool Cursor::bof() const
{
    return m_at==0;
}
 
TQ_LLONG Cursor::at() const
{
    if (m_readAhead)
        return 0;
    return m_at - 1;
}
 
bool Cursor::isBuffered() const
{
    return m_options & Buffered;
}
 
void Cursor::setBuffered(bool buffered)
{
    if (!m_opened)
        return;
    if (isBuffered()==buffered)
        return;
    m_options ^= Buffered;
}
 
void Cursor::clearBuffer()
{
    if ( !isBuffered() || m_fieldCount==0)
        return;
    
    drv_clearBuffer();
    
    m_records_in_buf=0;
    m_at_buffer=false;
}
 
bool Cursor::getNextRecord()
{
    m_result = -1; //by default: invalid result of row fetching
 
    if ((m_options & Buffered)) {//this cursor is buffered:
//      KexiDBDbg << "m_at < m_records_in_buf :: " << (long)m_at << " < " << m_records_in_buf << endl;
//js        if (m_at==-1) m_at=0;
        if (m_at < m_records_in_buf) {//we have next record already buffered:
//js            if (m_at_buffer && (m_at!=0)) {//we already have got a pointer to buffer
            if (m_at_buffer) {//we already have got a pointer to buffer
                drv_bufferMovePointerNext(); //just move to next record in the buffer
            } else {//we have no pointer
                //compute a place in the buffer that contain next record's data
                drv_bufferMovePointerTo(m_at-1+1);
//              drv_bufferMovePointerTo(m_at+1);
                m_at_buffer = true; //now current record is stored in the buffer
            }
        }
        else {//we are after last retrieved record: we need to physically fetch next record:
            if (!m_readAhead) {//we have no record that was read ahead
                if (!m_buffering_completed) {
                    //retrieve record only if we are not after 
                    //the last buffer's item (i.e. when buffer is not fully filled):
//                  KexiDBDbg<<"==== buffering: drv_getNextRecord() ===="<<endl;
                    drv_getNextRecord();
                }
                if ((FetchResult) m_result != FetchOK) {//there is no record
                    m_buffering_completed = true; //no more records for buffer
//                  KexiDBDbg<<"m_result != FetchOK ********"<<endl;
                    m_validRecord = false;
                    m_afterLast = true;
//js                    m_at = m_records_in_buf;
                    m_at = -1; //position is invalid now and will not be used
                    if ((FetchResult) m_result == FetchEnd) {
                        return false;
                    }
                    setError(ERR_CURSOR_RECORD_FETCHING, i18n("Cannot fetch next record."));
                    return false;
                }
                //we have a record: store this record's values in the buffer
                drv_appendCurrentRecordToBuffer();
                m_records_in_buf++;
            }
            else //we have a record that was read ahead: eat this
                m_readAhead = false;
        }
    }
    else {//we are after last retrieved record: we need to physically fetch next record:
        if (!m_readAhead) {//we have no record that was read ahead
//          KexiDBDbg<<"==== no prefetched record ===="<<endl;
            drv_getNextRecord();
            if ((FetchResult)m_result != FetchOK) {//there is no record
//              KexiDBDbg<<"m_result != FetchOK ********"<<endl;
                m_validRecord = false;
                m_afterLast = true;
                m_at = -1;
                if ((FetchResult) m_result == FetchEnd) {
                    return false;
                }
                setError(ERR_CURSOR_RECORD_FETCHING, i18n("Cannot fetch next record."));
                return false;
            }
        }
        else //we have a record that was read ahead: eat this
            m_readAhead = false;
    }
 
    m_at++;
    
//  if (m_data->curr_colname && m_data->curr_coldata)
//      for (int i=0;i<m_data->curr_cols;i++) {
//          KexiDBDbg<<i<<": "<< m_data->curr_colname[i]<<" == "<< m_data->curr_coldata[i]<<endl;
//      }
//  KexiDBDbg<<"m_at == "<<(long)m_at<<endl;
 
    m_validRecord = true;
    return true;
}
 
bool Cursor::updateRow(RowData& data, RowEditBuffer& buf, bool useROWID)
{
    clearError();
    if (!m_query)
        return false;
    return m_conn->updateRow(*m_query, data, buf, useROWID);
}
 
bool Cursor::insertRow(RowData& data, RowEditBuffer& buf, bool getROWID)
{
    clearError();
    if (!m_query)
        return false;
    return m_conn->insertRow(*m_query, data, buf, getROWID);
}
 
bool Cursor::deleteRow(RowData& data, bool useROWID)
{
    clearError();
    if (!m_query)
        return false;
    return m_conn->deleteRow(*m_query, data, useROWID);
}
 
bool Cursor::deleteAllRows()
{
    clearError();
    if (!m_query)
        return false;
    return m_conn->deleteAllRows(*m_query);
}
 
TQString Cursor::debugString() const
{
    TQString dbg = "CURSOR( ";
    if (!m_query) {
        dbg += "RAW STATEMENT: '";
        dbg += m_rawStatement;
        dbg += "'\n";
    }
    else {
        dbg += "QuerySchema: '";
        dbg += m_conn->selectStatement( *m_query );
        dbg += "'\n";
    }
    if (isOpened())
        dbg += " OPENED";
    else
        dbg += " NOT_OPENED";
    if (isBuffered())
        dbg += " BUFFERED";
    else
        dbg += " NOT_BUFFERED";
    dbg += " AT=";
    dbg += TQString::number((unsigned long)at());
    dbg += " )";
    return dbg;
}
 
void Cursor::debug() const
{
    KexiDBDbg << debugString() << endl;
}
 
void Cursor::setOrderByColumnList(const TQStringList& columnNames)
{
    Q_UNUSED(columnNames);
// all field names should be fooun, exit otherwise ..........
 
    // OK
//TODO  if (!m_orderByColumnList)
//TODO
}
 
void Cursor::setOrderByColumnList(const TQString& column1, const TQString& column2, 
    const TQString& column3, const TQString& column4, const TQString& column5)
{
    Q_UNUSED(column1);
    Q_UNUSED(column2);
    Q_UNUSED(column3);
    Q_UNUSED(column4);
    Q_UNUSED(column5);
}
 
QueryColumnInfo::Vector Cursor::orderByColumnList() const
{
    return m_orderByColumnList ? *m_orderByColumnList: QueryColumnInfo::Vector();
}
 
TQValueList<TQVariant> Cursor::queryParameters() const
{
    return m_queryParameters ? *m_queryParameters : TQValueList<TQVariant>();
}
 
void Cursor::setQueryParameters(const TQValueList<TQVariant>& params)
{
    if (!m_queryParameters)
        m_queryParameters = new TQValueList<TQVariant>(params);
    else
        *m_queryParameters = params;
}
 
#include "cursor.moc"