/FlightCrew-0.7.2/src/FlightCrew-gui/UpdateChecker.cpp

/************************************************************************

**

**  Copyright (C) 2010  Strahinja Markovic

**

**  This file is part of FlightCrew.

**

**  FlightCrew is free software: you can redistribute it and/or modify

**  it under the terms of the GNU Lesser General Public License as published

**  by the Free Software Foundation, either version 3 of the License, or

**  (at your option) any later version.

**

**  FlightCrew 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 Lesser General Public License for more details.

**

**  You should have received a copy of the GNU Lesser General Public License

**  along with FlightCrew.  If not, see <http://www.gnu.org/licenses/>.

**

*************************************************************************/



#include <QRegExp>

#include <QSettings>

#include <QNetworkAccessManager>

#include <QNetworkRequest>

#include <QNetworkReply>

#include <QDateTime>

#include <QMessageBox>

#include <QDesktopServices>

#include <QXmlStreamReader>

#include <QTextStream>

#include "UpdateChecker.h"



static const QString DOWNLOAD_PAGE_LOCATION  = "http://code.google.com/p/flightcrew/downloads/list";

static const QString UPDATE_XML_LOCATION     = "http://flightcrew.googlecode.com/git/version.xml";

static const QString XML_VERSION_ELEMENT     = "current-version";

static const QString LAST_ONLINE_VERSION_KEY = "last_online_version";

static const QString LAST_CHECK_TIME_KEY     = "last_check_time";

static const QString SETTINGS_GROUP          = "updatechecker";

static const QString VERSION_NUMBERS         = "(\\d+)\\.(\\d+)\\.(\\d+)";

static const QString FLIGHTCREW_VERSION      = QString( FLIGHTCREW_FULL_VERSION );



// Delta is six hours

static const int SECONDS_BETWEEN_CHECKS      = 60 * 60 * 6 ;





UpdateChecker::UpdateChecker( QObject *parent )

    : 

    QObject( parent ),

    m_NetworkManager( new QNetworkAccessManager( this ) )

{

    connect(    m_NetworkManager,  SIGNAL( finished( QNetworkReply* ) ),

                this,              SLOT( ReplyRecieved( QNetworkReply* ) )

           );

}





void UpdateChecker::CheckForUpdate()

{

    QSettings settings;

    settings.beginGroup( SETTINGS_GROUP );



    // The default time is one always longer than the check interval

    QDateTime default_time    = QDateTime::currentDateTime().addSecs( - SECONDS_BETWEEN_CHECKS - 1 );

    QDateTime last_check_time = settings.value( LAST_CHECK_TIME_KEY, default_time ).toDateTime();



    // We want to check for a new version

    // no sooner than every six hours

    if ( last_check_time.secsTo( QDateTime::currentDateTime() ) > SECONDS_BETWEEN_CHECKS )

    {

        settings.setValue( LAST_CHECK_TIME_KEY, QDateTime::currentDateTime() );



        m_NetworkManager->get( QNetworkRequest( QUrl( UPDATE_XML_LOCATION ) ) );        

    }

}





void UpdateChecker::ReplyRecieved( QNetworkReply* reply )

{

    QSettings settings;

    settings.beginGroup( SETTINGS_GROUP );



    QString last_online_version    = settings.value( LAST_ONLINE_VERSION_KEY, QString() ).toString();

    QString current_online_version = ReadOnlineVersion( TextInReply( reply ) );



    bool is_newer = IsOnlineVersionNewer( FLIGHTCREW_VERSION, current_online_version );



    // The message box is displayed only if the online version is newer

    // and only if the user hasn't been informed about this release before

    if ( is_newer && ( current_online_version != last_online_version ) )

    {

        QMessageBox::StandardButton button_clicked;



        button_clicked = QMessageBox::question(  0,

                     QObject::tr( "FlightCrew" ),

                     QObject::tr( "<p>A newer version of FlightCrew is available, version <b>%1</b>.<br/>"

                         "The ChangeLog can be seen <a href='http://flightcrew.googlecode.com/git/ChangeLog.txt'>here</a>.</p>"

                         "<p>Would you like to go to the download page?</p>" )

                     .arg( current_online_version ),

                     QMessageBox::Yes | QMessageBox::No,

                     QMessageBox::Yes );



        if ( button_clicked == QMessageBox::Yes )

        {

            QDesktopServices::openUrl( QUrl( DOWNLOAD_PAGE_LOCATION ) );

        }

    }



    // Store the current online version as the last one checked

    settings.setValue( LAST_ONLINE_VERSION_KEY, current_online_version );



    // Schedule this object for deletion.

    // There is no point for its existence

    // after it has received and processed the net reply. 

    deleteLater();

}





QString UpdateChecker::TextInReply( QNetworkReply* reply ) const

{

    if ( !reply->open( QIODevice::ReadOnly | QIODevice::Text ) )

    {

        return "";

    }



    QTextStream in( reply );



    // Input should be UTF-8

    in.setCodec( "UTF-8" );



    // This will automatically switch reading from

    // UTF-8 to UTF-16 if a BOM is detected

    in.setAutoDetectUnicode( true );



    return in.readAll();

}





QString UpdateChecker::ReadOnlineVersion( const QString &online_version_xml ) const

{

    if ( online_version_xml.isEmpty() )



        return QString();



    QXmlStreamReader version_reader( online_version_xml );



    while ( !version_reader.atEnd() ) 

    {

        // Get the next token from the stream

        if ( ( version_reader.readNext() == QXmlStreamReader::StartElement ) &&

             ( version_reader.name() == XML_VERSION_ELEMENT )

           ) 

        {

           return version_reader.readElementText();

        }

    }



    return QString();

}





bool UpdateChecker::IsOnlineVersionNewer( const QString &current_version_string,

                                          const QString &online_version_string ) const

{

    if ( current_version_string.isEmpty() || online_version_string.isEmpty() )



        return false;



    QRegExp current_version_numbers( VERSION_NUMBERS );

    QString( current_version_string ).indexOf( current_version_numbers );



    QRegExp online_version_numbers( VERSION_NUMBERS );

    QString( online_version_string ).indexOf( online_version_numbers );



    // This code assumes three digits per field,

    // which should be way more than enough

    int current_version = current_version_numbers.cap( 1 ).toInt() * 1000000 +

                          current_version_numbers.cap( 2 ).toInt() * 1000 +

                          current_version_numbers.cap( 3 ).toInt();



    int online_version = online_version_numbers.cap( 1 ).toInt() * 1000000 +

                         online_version_numbers.cap( 2 ).toInt() * 1000 +

                         online_version_numbers.cap( 3 ).toInt();



    return online_version > current_version;

}