installer-framework/installerbuilder/libinstaller/environmentvariablesoperation.cpp

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** contained in the Technology Preview License Agreement accompanying
** this package.
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** GNU Lesser General Public License Usage
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** License version 2.1 as published by the Free Software Foundation and
** appearing in the file LICENSE.LGPL included in the packaging of this file.
** Please review the following information to ensure the GNU Lesser General
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#include "environmentvariablesoperation.h"

#include <stdlib.h>

#include <QtCore/QSettings>

#include "KDUpdater/environment.h"

// this makes us use QSettingsWrapper
#include "fsengineclient.h"

#ifdef Q_WS_WIN
# include <windows.h>
#endif

using namespace QInstaller;

/*
TRANSLATOR QInstaller::EnvironmentVariablesOperation
*/

EnvironmentVariableOperation::EnvironmentVariableOperation()
{
    setName(QLatin1String("EnvironmentVariable"));
}

EnvironmentVariableOperation::~EnvironmentVariableOperation()
{
}

void EnvironmentVariableOperation::backup()
{
}

using namespace KDUpdater;

#ifdef Q_WS_WIN
static bool broadcastChange() {
    // Use SendMessageTimeout to Broadcast a message to the whole system to update settings of all
    // running applications. This is needed to activate the changes done above without logout+login.
    // Note that cmd.exe does not respond to any WM_SETTINGCHANGE messages...
    DWORD aResult = 0;
    LRESULT sendresult = SendMessageTimeout( HWND_BROADCAST, WM_SETTINGCHANGE,
        0, (LPARAM) "Environment", SMTO_BLOCK | SMTO_ABORTIFHUNG, 5000, &aResult );
    if( sendresult == 0 || aResult != 0 ) {
        qWarning( "Failed to broadcast a WM_SETTINGCHANGE message\n" );
        return false;
    }

    return true;
}
#endif

namespace {

template <typename SettingsType>
UpdateOperation::Error writeSetting(const QString &regPath,
                                    const QString &name,
                                    const QString &value,
                                    QString *errorString,
                                    QString *oldValue) {
    oldValue->clear();
    SettingsType registry(regPath, QSettings::NativeFormat);
    if (!registry.isWritable()) {
        *errorString = QObject::tr("Registry path %1 is not writable").arg(regPath);
        return UpdateOperation::UserDefinedError;
    }

    // remember old value for undo
    *oldValue = registry.value(name).toString();

    // set the new value
    registry.setValue(name, value);
    registry.sync();

    if(registry.status() != QSettings::NoError) {
        *errorString = QObject::tr("Could not write to registry path %1").arg(regPath);
        return UpdateOperation::UserDefinedError;
    }

    return UpdateOperation::NoError;
}

template <typename SettingsType>
UpdateOperation::Error undoSetting(const QString &regPath,
                                    const QString &name,
                                    const QString &value,
                                    const QString &oldValue,
                                    QString *errorString) {
    QString actual;
    {
        SettingsType registry(regPath, QSettings::NativeFormat);
        actual = registry.value(name).toString();
    }
    if (actual != value) //key changed, don't undo
        return UpdateOperation::UserDefinedError;
    else {
        QString dontcare;
        return writeSetting<SettingsType>(regPath, name, oldValue, errorString, &dontcare);
    }
}

}

bool EnvironmentVariableOperation::performOperation()
{
    if (arguments().count() < 2 || arguments().count() > 4) {
        setError(InvalidArguments);
        setErrorString(tr("Invalid arguments in %0: %1 arguments given, 2-3 expected.")
                        .arg(name()).arg( arguments().count()));
        return false;
    }

    const QString name = arguments().at(0);
    const QString value = arguments().at(1);
    bool isPersistent = false;

#ifdef Q_WS_WIN
    isPersistent = arguments().count() >= 3 ? arguments().at(2) == QLatin1String("true") : true;
    const bool isSystemWide = arguments().count() >= 4 ? arguments().at(3) == QLatin1String("true") : false;
    QString oldvalue;
    if (isPersistent) {
        const QString regPath = isSystemWide ? QLatin1String( "HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment" )
                                             : QLatin1String( "HKEY_CURRENT_USER\\Environment" );

        // write the name=value pair to the global environment
        QString errorString;

        Error err = NoError;

        err = isSystemWide
            ? writeSetting<QSettingsWrapper>(regPath, name, value, &errorString, &oldvalue)
            : writeSetting<QSettings>(regPath, name, value, &errorString, &oldvalue);
        if (err != NoError) {
            setError(err);
            setErrorString(errorString);
            return false;
        }
        const bool bret = broadcastChange();
        Q_UNUSED(bret); // this is not critical, so fall-through
        setValue( QLatin1String( "oldvalue" ), oldvalue );
        return true;
    }
#endif
    Q_ASSERT( !isPersistent );

    setValue( QLatin1String( "oldvalue" ), Environment::instance()->value( name ) );
    Environment::instance()->setTemporaryValue( name, value );

    return true;
}

bool EnvironmentVariableOperation::undoOperation()
{
    if (arguments().count() < 2 || arguments().count() > 4)
        return false;

    const QString name = arguments().at(0);
    const QString value = arguments().at(1);
    const QString oldvalue = this->value( QLatin1String("oldvalue") ).toString();

#ifdef Q_WS_WIN
    const bool isPersistent = arguments().count() >= 3 ? arguments().at(2) == QLatin1String("true") : true;
#else
   const bool isPersistent = false;
#endif

    if ( !isPersistent ) {
        const QString actual = Environment::instance()->value( name );
        const bool doUndo = actual == value;
        if ( doUndo )
            Environment::instance()->setTemporaryValue( name, oldvalue );
        return doUndo;
    }

#ifdef Q_WS_WIN
    const bool isSystemWide = arguments().count() >= 4 ? arguments().at(3) == QLatin1String("true") : false;

    const QString regPath = isSystemWide ? QLatin1String( "HKEY_LOCAL_MACHINE\\SYSTEM\\CurrentControlSet\\Control\\Session Manager\\Environment" )
                                         : QLatin1String( "HKEY_CURRENT_USER\\Environment" );

    QString errorString;

    const Error err = isSystemWide
        ? undoSetting<QSettingsWrapper>(regPath, name, value, oldvalue, &errorString)
        : undoSetting<QSettings>(regPath, name, value, oldvalue, &errorString);

    if  (err != NoError) {
        setError(err);
        setErrorString(errorString);
        return false;
    }
#endif

    return true;
}

bool EnvironmentVariableOperation::testOperation()
{
    return true;
}

EnvironmentVariableOperation* EnvironmentVariableOperation::clone() const
{
    return new EnvironmentVariableOperation();
}