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/*!
    \contentspage{index.html}{Qt Installer Framework}
    \previouspage noninteractive.html
    \page scripting.html
    \nextpage operations.html

    \title Component Scripting

    For each component, you can specify one script that prepares the operations
    to be performed by the installer. The script format has to be
    compatible with QJSEngine.

    \section1 Construction

    The script has to contain a \c Component object that the installer creates
    when it loads the script. Therefore, the script must contain at
    least the \c Component() function, which performs initialization, such as
    putting pages in the correct places or connecting signals and slots.

    The following code snippet places the \c ErrorPage (which is the class
    name of the user interface file loaded from errorpage.ui) in front of the
    ready for installation page and sets its completeness to \c false.

    \code
    function Component()
    {
        // Add a user interface file called ErrorPage, which should not be complete
        installer.addWizardPage( component, "ErrorPage", QInstaller.ReadyForInstallation );
        component.userInterface( "ErrorPage" ).complete = false;
    }
    \endcode

    For more information, see the documentation for \l installer::addWizardPage() and
    \l component::userInterface().

    \section1 Installer Hooks

    You can add the following hook methods into your script:

    \table
        \header
            \li Method
            \li Description
        \row
            \li \c{Component.prototype.retranslateUi}
            \li Called when the language of the installer changes.
        \row
            \li \c{Component.prototype.createOperations}
            \li See \l component::createOperations().
        \row
            \li \c{Component.prototype.createOperationsForArchive}
            \li See \l component::createOperationsForArchive().
        \row
            \li \c{Component.prototype.createOperationsForPath}
            \li See \l component::createOperationsForPath().
    \endtable

    \section1 Global Variables

    The installer puts the following symbols into the script space:

    \table
        \header
            \li Symbol
            \li Description
        \row
            \li installer
            \li Reference to the \l QInstaller of the component
        \row
            \li component
            \li Reference to the \l Component of the component
    \endtable

    \section1 Message Boxes

    You can show a QMessageBox from within the script by using the following
    static members:

    \list
    \li QMessageBox::critical()
    \li QMessageBox::information()
    \li QMessageBox::question()
    \li QMessageBox::warning()
    \endlist

    For your convenience, the values for QMessageBox::StandardButton are made
    available by using \c QMessageBox.Ok, \c QMessageBox.Open, and so on.

    \section1 Adding Operations to Components

    You might want to add custom operations after extracting the content, when
    copying files or patching file content, for example. You can create and add
    update operations to the installation from within a script using
    component::addOperation(). If you need to run an operation that requires
    administrative rights, use component::addElevatedOperation() instead.

    Operations need to be added before the actual installation step. Override
    \l component::createOperations() to register custom operations for a
    component.

    Each operation has a unique key used for identification and can take up to
    five parameters. In the parameter values, you can use variables as set in
    installer::setValue(). For more information, see \l{Predefined Variables}.

    For a summary of all available operations, see \l{Operations}.

    \section1 Registering Custom Operations

    You can register custom installation operations in the installer by deriving
    the KDUpdater::UpdateOperation class. The following code displays the
    methods that you must implement:

  \code
  #include <KDUpdater/UpdateOperation>

  class CustomOperation : public KDUpdater::UpdateOperation
  {
  public:
    CustomOperation()
    {
        setName( "CustomOperation" );
    }

    void backup()
    {
        // do whatever is needed to restore the state in undoOperation()
    }

    bool performOperation()
    {
        const QStringList args = arguments();
        // do whatever is needed to do for the given arguments

        bool success = ...;
        return success;
    }

    void undoOperation()
    {
        // restore the previous state, as saved in backup()
    }

    bool testOperation()
    {
        // currently unused
        return true;
    }

    CustomOperation* clone() const
    {
        return new CustomOperation;
    }

    QDomDocument toXml()
    {
        // automatically adds the operation's arguments and everything set via setValue
        QDomDocument doc = KDUpdater::UpdateOperation::toXml();

        // if you need any information to undo the operation you did,
        // add them to the doc here

        return doc;
    }

    bool fromXml( const QDomDocument& doc )
    {
        // automatically loads the operation's arguments and everything set via setValue
        if( !KDUpdater::UpdateOperation::fromXml( doc ) )
            return false;

        // if you need any information to undo the operation you did,
        // read them from the doc here

        return true;
    }
  };
  \endcode

    Finally, you need to register your custom operation class, as follows:
  \code
  #include <KDupdater/UpdateOperationFactory>

  KDUpdater::UpdateOperationFactory::instance().registerUpdateOperation< CustomOperation >( "CustomOperation" );
  \endcode

    Now you can use your operation in the installer in the same way as the
    predefined operations.

  \section1 Predefined Variables

    You can use the following predefined variables in scripts to facilitate
    directory access:

    \table
        \header
            \li Symbol
            \li Description
        \row
            \li ProductName
            \li Name of the product to be installed, as defined in config.xml.
        \row
            \li ProductVersion
            \li Version number of the product to be installed, as defined in
                config.xml.
        \row
            \li Title
            \li Title of the installation program, as defined in config.xml.
        \row
            \li Publisher
            \li Publisher of the installation program, as defined in config.xml.
        \row
            \li Url
            \li Product URL, as defined in config.xml.
        \row
            \li StartMenuDir
            \li Start menu group, as defined in config.xml. Only available on Windows.
        \row
            \li TargetDir
            \li Target directory for installation, as selected by the user.
        \row
            \li DesktopDir
            \li Name of the directory that contains the user's desktop.

            Only available on Windows.
        \row
            \li os
            \li Current platform: \c "x11", \c "win", or \c "mac".

                This variable is deprecated: Use \l systemInfo instead.
        \row
            \li RootDir
            \li Root directory of the filesystem.
        \row
            \li HomeDir
            \li Home directory of the current user.
        \row
            \li ApplicationsDir
            \li Applications directory.

                For example, \c {C:\Program Files} on Windows,
                \c {/opt} on Linux and \c {/Applications} on OS X.
        \row
            \li InstallerDirPath
            \li The directory that contains the installer application executable.
        \row
            \li InstallerFilePath
            \li The file path of the installer application executable.
        \row
            \li UserStartMenuProgramsPath
            \li The path to the folder containing the items in the Start menu of the user.

                For example, \c {C:\Users\USERNAME\AppData\Roaming\Microsoft\Windows\Start Menu\Programs}

                Only available on Windows.
        \row
            \li AllUsersStartMenuProgramsPath
            \li The path to the folder containing the items in the Start menu for all users.

                For example, \c {C:\ProgramData\Microsoft\Windows\Start Menu\Programs}

                Only available on Windows.
    \endtable

    The variables can be resolved by calls to installer::value(). If embedded
    in '@' they can also be part of strings passed as arguments to installation
    operations:

    \code
    if (installer.value("os") === "win") {
        component.addOperation("CreateShortcut", "@TargetDir@/MyApp.exe", "@StartMenuDir@/MyApp.lnk");
    }
    \endcode
*/
