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# Qt Distribution Example

This example program modifies the hard-coded paths that are compiled into the Qt library.

When distributing the Qt library, the final installation prefix is very rarely the same as the prefix used when doing development. You can use the code from this example to modify the following hard-coded paths in Qt library:

- Prefix - Normally, all other paths are relative to the Prefix.

- Binaries - Location of binaries distributed with Qt (for example, Qt Assistant).

- Documentation - Location of the Qt documentation.

- Headers - Location of the Qt headers.

- Libraries - Location of addition libraries distributed with Qt (for example, the qui library).

- Plugins - Location of the Qt plugins.

- Data - Location of applicaton specific data for all programs distributed with Qt.

Implementation:

    /****************************************************************************
    ** ui.h extension file, included from the uic-generated form implementation.
    **
    ** If you wish to add, delete or rename functions or slots use
    ** Qt Designer which will update this file, preserving your code. Create an
    ** init() function in place of a constructor, and a destroy() function in
    ** place of a destructor.
    *****************************************************************************/

    #include <qapplication.h>
    #include <qcursor.h>
    #include <qeventloop.h>
    #include <qfile.h>
    #include <qfiledialog.h>
    #include <qfileinfo.h>
    #include <qlineedit.h>
    #include <qmessagebox.h>
    #include <qpushbutton.h>
    #include <qtimer.h>

    void Distributor::init()
    {
        timer = new QTimer( this );
        connect( timer, SIGNAL(timeout()), SLOT(checkLibData()) );

        cancelButton()->setAutoDefault( FALSE );
        backButton()->setAutoDefault( FALSE );

        setNextEnabled( selectLibrary, FALSE );

        setHelpEnabled( selectLibrary, FALSE );
        setHelpEnabled( modifyPaths, FALSE );
        setHelpEnabled( verifyMods, FALSE );

        setFinishEnabled( verifyMods, TRUE );
    }

    void Distributor::showPage( QWidget *page )
    {
        if ( page == selectLibrary ) {
            nextButton()->setDefault( TRUE );
            libFilename->setFocus();
        } else if ( page == modifyPaths ) {
            nextButton()->setDefault( TRUE );
            prefixPath->selectAll();
            prefixPath->setFocus();
        } else if ( page == verifyMods ) {
            finishButton()->setDefault( TRUE );
            finishButton()->setFocus();

            QString labeltext =
                tr("<p><b>Current Library File:</b> %1</p>"
                   "<table border=0>"
                   "<tr><td><b>New Installation Prefix:</b></td><td>%2</td></tr>"
                   "<tr><td></td><td></td></tr>"
                   "<tr><td><b>Binaries Path:</b></td><td>%3</td></tr>"
                   "<tr><td><b>Documentation Path:</b></td><td>%4</td></tr>"
                   "<tr><td><b>Headers Path:</b></td><td>%5</td></tr>"
                   "<tr><td><b>Libraries Path:</b></td><td>%6</td></tr>"
                   "<tr><td><b>Plugins Path:</b></td><td>%7</td></tr>"
                   "<tr><td><b>Data Path:</b></td><td>%8</td></tr>"
                   "</table>"
                   "<p>Please verify that these options are correct.  Press the "
                   "<i>Finish</i> button to apply these modifications to the Qt "
                   "library.  Use the <i>Back</i> button to make corrections.  Use "
                   "the <i>Cancel</i> button to abort.</p>")
                .arg( libFilename->text() )
                .arg( prefixPath->text() )
                .arg( binPath->text() )
                .arg( docPath->text() )
                .arg( hdrPath->text() )
                .arg( libPath->text() )
                .arg( plgPath->text() )
                .arg( datPath->text() );
            textLabel4->setText( labeltext );
        }

        QWizard::showPage( page );
    }

    void Distributor::checkLibFilename( const QString &filename )
    {
        setNextEnabled( selectLibrary, FALSE );

        QFileInfo fileinfo( filename );
        if ( ! filename.isEmpty() && fileinfo.exists() &&
             fileinfo.isReadable() && fileinfo.isWritable() &&
             fileinfo.isFile() && !fileinfo.isSymLink() )
            timer->start( 500, TRUE );
    }

    void Distributor::browseLibFilename()
    {
        QString filename =
            QFileDialog::getOpenFileName( QString::null, QString::null, this );
        libFilename->setText( filename );
    }

    static char *find_pattern( char *h, const char *n, ulong hlen )
    {
        if ( ! h || ! n || hlen == 0 )
            return 0;

    #ifdef Q_OS_UNIX
        size_t nlen;
    #else
        ulong nlen;
    #endif

        char nc = *n++;
        nlen = strlen( n );
        char hc;

        do {
            do {
                hc = *h++;
                if ( hlen-- < 1 )
                    return 0;
            } while ( hc != nc );

            if ( nlen > hlen )
                return 0;
        } while ( qstrncmp( h, n, nlen ) != 0 );
        return h + nlen;
    }

    void Distributor::checkLibData()
    {
        struct step {
            const char *key;
            QCString value;
            bool done;
        } steps[7];

        steps[0].key = "qt_nstpath=";
        steps[0].done = FALSE;

        steps[1].key = "qt_binpath=";
        steps[1].done = FALSE;

        steps[2].key = "qt_docpath=";
        steps[2].done = FALSE;

        steps[3].key = "qt_hdrpath=";
        steps[3].done = FALSE;

        steps[4].key = "qt_libpath=";
        steps[4].done = FALSE;

        steps[5].key = "qt_plgpath=";
        steps[5].done = FALSE;

        steps[6].key = "qt_datpath=";
        steps[6].done = FALSE;

        uint completed = 0;
        uint total_steps = sizeof(steps) / sizeof(step);

        QFile file( libFilename->text() );
        if ( file.open( IO_ReadOnly ) ) {
            QApplication::setOverrideCursor( WaitCursor );

            // instead of reading in the entire file, do the search in chunks
            char data[60000];
            ulong offset = 0;

            while ( ! file.atEnd() && completed < total_steps ) {
                QApplication::eventLoop()->processEvents( QEventLoop::ExcludeUserInput );

                ulong len = file.readBlock( data, sizeof(data) );
                if ( len < 267 ) {
                    // not enough room to make any modifications... stop
                    break;
                }

                for ( uint x = 0; x < total_steps; ++x ) {
                    if ( steps[x].done ) continue;

                    char *s = find_pattern( data, steps[x].key, len );
                    if ( s ) {
                        ulong where = s - data;
                        if ( len - where < 256 ) {
                            // not enough space left to write the full
                            // path... move the file pointer back to just
                            // before the pattern and continue
                            offset += where - 11;
                            file.at( offset );
                            len = file.readBlock( data, sizeof(data) );
                            --x; // retry the current step
                            continue;
                        }

                        steps[x].value = s;
                        steps[x].done = TRUE;

                        ++completed;
                    }
                }

                // move to the new read position
                offset += len - 11;
                file.at( offset );
            }

            file.close();

            QApplication::restoreOverrideCursor();
        }

        if ( completed == total_steps ) {
            setNextEnabled( selectLibrary, TRUE );

            QString prefix = QFile::decodeName( steps[0].value );
            prefixPath->setText( prefix );

            QString def_bin = prefix + QString::fromLatin1( "/bin" );
            QString def_doc = prefix + QString::fromLatin1( "/doc" );
            QString def_hdr = prefix + QString::fromLatin1( "/include" );
            QString def_lib = prefix + QString::fromLatin1( "/lib" );
            QString def_plg = prefix + QString::fromLatin1( "/plugins" );
            QString def_dat = prefix;

            QString bin = QFile::decodeName( steps[1].value );
            QString doc = QFile::decodeName( steps[2].value );
            QString hdr = QFile::decodeName( steps[3].value );
            QString lib = QFile::decodeName( steps[4].value );
            QString plg = QFile::decodeName( steps[5].value );
            QString dat = QFile::decodeName( steps[6].value );

            autoSet->setChecked( def_bin == bin &&
                                 def_doc == doc &&
                                 def_hdr == hdr &&
                                 def_lib == lib &&
                                 def_plg == plg &&
                                 def_dat == dat );

            if ( ! autoSet->isChecked() ) {
                binPath->setText( bin );
                docPath->setText( doc );
                hdrPath->setText( hdr );
                libPath->setText( lib );
                plgPath->setText( plg );
                datPath->setText( dat );
            }
        }
    }

    void Distributor::checkInstallationPrefix( const QString &prefix )
    {
        if ( autoSet->isChecked() ) {
            binPath->setText( prefix + QString::fromLatin1( "/bin" ) );
            docPath->setText( prefix + QString::fromLatin1( "/doc" ) );
            hdrPath->setText( prefix + QString::fromLatin1( "/include" ) );
            libPath->setText( prefix + QString::fromLatin1( "/lib" ) );
            plgPath->setText( prefix + QString::fromLatin1( "/plugins" ) );
            datPath->setText( prefix );
        }
    }

    void Distributor::browseInstallationPrefix()
    {
        QString prefix =
            QFileDialog::getOpenFileName( QString::null, QString::null, this );
        prefixPath->setText( prefix );
    }

    void Distributor::toggleAutoSet( bool autoset )
    {
        if ( autoset ) checkInstallationPrefix( prefixPath->text() );
    }

    void Distributor::accept()
    {
        struct step {
            const char *key;
            QCString value;
            bool done;
        } steps[7];

        steps[0].key = "qt_nstpath=";
        steps[0].value = QFile::encodeName( prefixPath->text() );
        steps[0].done = FALSE;

        steps[1].key = "qt_binpath=";
        steps[1].value = QFile::encodeName( binPath->text() );
        steps[1].done = FALSE;

        steps[2].key = "qt_docpath=";
        steps[2].value = QFile::encodeName( docPath->text() );
        steps[2].done = FALSE;

        steps[3].key = "qt_hdrpath=";
        steps[3].value = QFile::encodeName( hdrPath->text() );
        steps[3].done = FALSE;

        steps[4].key = "qt_libpath=";
        steps[4].value = QFile::encodeName( libPath->text() );
        steps[4].done = FALSE;

        steps[5].key = "qt_plgpath=";
        steps[5].value = QFile::encodeName( plgPath->text() );
        steps[5].done = FALSE;

        steps[6].key = "qt_datpath=";
        steps[6].value = QFile::encodeName( datPath->text() );
        steps[6].done = FALSE;

        uint completed = 0;
        uint total_steps = sizeof(steps) / sizeof(step);

        QFile file( libFilename->text() );
        if ( file.open( IO_ReadWrite ) ) {
            QApplication::setOverrideCursor( WaitCursor );

            // instead of reading in the entire file, do the search in chunks
            char data[60000];
            ulong offset = 0;

            while ( ! file.atEnd() && completed < total_steps ) {
                QApplication::eventLoop()->processEvents( QEventLoop::ExcludeUserInput );

                ulong len = file.readBlock( data, sizeof(data) );
                if ( len < 267 ) {
                    // not enough room to make any modifications... stop
                    break;
                }

                uint completed_save = completed;
                for ( uint x = 0; x < total_steps; ++x ) {
                    if ( steps[x].done ) continue;

                    char *s = find_pattern( data, steps[x].key, len );
                    if ( s ) {
                        ulong where = s - data;
                        if ( len - where < 256 ) {
                            // not enough space left to write the full
                            // path... move the file pointer back to just
                            // before the pattern and continue
                            offset += where - 11;
                            file.at( offset );
                            len = file.readBlock( data, sizeof(data) );
                            --x; // retry the current step
                            continue;
                        }

                        qstrcpy( s, steps[x].value );
                        steps[x].done = TRUE;

                        ++completed;
                    }
                }

                if ( completed != completed_save ) {
                    // something changed...  move file pointer back to
                    // where the data was read and write the new data
                    file.at( offset );
                    file.writeBlock( data, len );
                }

                // move to the new read position
                offset += len - 11;
                file.at( offset );
            }

            file.close();

            QApplication::restoreOverrideCursor();
        }

        if ( completed != total_steps ) {
            QMessageBox::information( this,
                                      tr("Qt Distribution Wizard"),
                                      tr("<p><h3>Modifications failed.</h3></p>"
                                         "<p>Please make sure that you have permission "
                                         "to write the selected file, and that the library "
                                         "is properly built.</p>") );
            return;
        }

        QWizard::accept();
    }

See also Examples.