Merge branch 'requirements-checking'

src/calamares/CalamaresApplication.cpp

@@ -348,6 +348,7 @@ void
 CalamaresApplication::initViewSteps()
 {
     cDebug() << "STARTUP: loadModules for all modules done";
+    m_moduleManager->checkRequirements();
     if ( Calamares::Branding::instance()->windowMaximize() )
     {
         m_mainwindow->setWindowFlag( Qt::FramelessWindowHint );
@@ -355,6 +356,7 @@ CalamaresApplication::initViewSteps()
     }
     else
         m_mainwindow->show();
+
     ProgressTreeModel* m = new ProgressTreeModel( nullptr );
     ProgressTreeView::instance()->setModel( m );
     cDebug() << "STARTUP: Window now visible and ProgressTreeView populated";

src/libcalamaresui/CMakeLists.txt

@@ -5,6 +5,8 @@ set( calamaresui_SOURCES
     modulesystem/Module.cpp
     modulesystem/ModuleManager.cpp
     modulesystem/ProcessJobModule.cpp
+    modulesystem/Requirement.cpp
+    modulesystem/RequirementsChecker.cpp
     modulesystem/ViewModule.cpp
 
     utils/CalamaresUtilsGui.cpp

src/libcalamaresui/modulesystem/Module.cpp

@@ -281,4 +281,10 @@ Module::initFrom( const QVariantMap& moduleDescriptor )
         m_maybe_emergency = moduleDescriptor[ EMERGENCY ].toBool();
 }
 
+RequirementsList
+Module::checkRequirements()
+{
+    return RequirementsList();
+}
+
 } //ns

src/libcalamaresui/modulesystem/Module.h

@@ -1,6 +1,7 @@
 /* === This file is part of Calamares - <https://github.com/calamares> ===
  *
  *   Copyright 2014-2015, Teo Mrnjavac <teo@kde.org>
+ *   Copyright 2017, Adriaan de Groot <groot@kde.org>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -19,6 +20,7 @@
 #ifndef CALAMARES_MODULE_H
 #define CALAMARES_MODULE_H
 
+#include "Requirement.h"
 #include "UiDllMacro.h"
 
 #include <Typedefs.h>
@@ -178,6 +180,11 @@ public:
      */
     QVariantMap configurationMap();
 
+    /**
+     * @brief Check the requirements of this module.
+     */
+    virtual RequirementsList checkRequirements();
+
 protected:
     explicit Module();
     virtual void initFrom( const QVariantMap& moduleDescriptor );

src/libcalamaresui/modulesystem/ModuleManager.cpp

@@ -21,26 +21,23 @@
 
 #include "ExecutionViewStep.h"
 #include "Module.h"
-#include "utils/Logger.h"
+#include "RequirementsChecker.h"
-#include "utils/YamlUtils.h"
 #include "Settings.h"
 #include "ViewManager.h"
 
+#include "utils/Logger.h"
+#include "utils/YamlUtils.h"
+
 #include <yaml-cpp/yaml.h>
 
 #include <QApplication>
 #include <QDir>
 #include <QTimer>
 
-#define MODULE_CONFIG_FILENAME "module.desc"
-
 namespace Calamares
 {
-
-
 ModuleManager* ModuleManager::s_instance = nullptr;
 
-
 ModuleManager*
 ModuleManager::instance()
 {
@@ -94,7 +91,7 @@ ModuleManager::doInit()
                 bool success = currentDir.cd( subdir );
                 if ( success )
                 {
-                    QFileInfo descriptorFileInfo( currentDir.absoluteFilePath( MODULE_CONFIG_FILENAME ) );
+                    QFileInfo descriptorFileInfo( currentDir.absoluteFilePath( QLatin1Literal( "module.desc") ) );
                     if ( ! ( descriptorFileInfo.exists() && descriptorFileInfo.isReadable() ) )
                     {
                         cDebug() << Q_FUNC_INFO << "unreadable file: "
@@ -307,6 +304,26 @@ ModuleManager::loadModules()
     } );
 }
 
+void
+ModuleManager::checkRequirements()
+{
+    cDebug() << "Checking module requirements ..";
+
+    QVector< Module* > modules( m_loadedModulesByInstanceKey.count() );
+    int count = 0;
+    for (const auto& module : m_loadedModulesByInstanceKey )
+    {
+        modules[count++] = module;
+    }
+
+    RequirementsChecker *rq = new RequirementsChecker( modules, this );
+    connect( rq, &RequirementsChecker::requirementsResult, this, &ModuleManager::requirementsResult );
+    connect( rq, &RequirementsChecker::requirementsComplete, this, &ModuleManager::requirementsComplete );
+    connect( rq, &RequirementsChecker::requirementsProgress, this, &ModuleManager::requirementsProgress );
+    connect( rq, &RequirementsChecker::done, rq, &RequirementsChecker::deleteLater );
+
+    QTimer::singleShot( 0, rq, &RequirementsChecker::run );
+}
 
 QStringList
 ModuleManager::checkDependencies()
@@ -334,8 +351,6 @@ ModuleManager::checkDependencies()
                     break;
                 }
             }
-            if ( somethingWasRemovedBecauseOfUnmetDependencies )
-                break;
         }
         if ( !somethingWasRemovedBecauseOfUnmetDependencies )
             break;
@@ -369,4 +384,4 @@ ModuleManager::checkDependencies( const Module& m )
     return allRequirementsFound;
 }
 
-}
+}  // namespace

src/libcalamaresui/modulesystem/ModuleManager.h

@@ -20,6 +20,7 @@
 #ifndef MODULELOADER_H
 #define MODULELOADER_H
 
+#include "Requirement.h"
 #include "Typedefs.h"
 
 #include <QObject>
@@ -30,6 +31,7 @@ namespace Calamares
 {
 
 class Module;
+struct RequirementEntry;  // from Requirement.h
 
 /**
  * @brief The ModuleManager class is a singleton which manages Calamares modules.
@@ -81,10 +83,20 @@ public:
      */
     void loadModules();
 
+    /**
+     * @brief Starts asynchronous requirements checking for each module.
+     * When this is done, the signal modulesChecked is emitted.
+     */
+    void checkRequirements();
+
 signals:
     void initDone();
     void modulesLoaded();  /// All of the modules were loaded successfully
     void modulesFailed( QStringList );   /// .. or not
+    // Below, see RequirementsChecker documentation
+    void requirementsComplete( bool );
+    void requirementsResult( RequirementsList );
+    void requirementsProgress( const QString& );
 
 private slots:
     void doInit();

src/libcalamaresui/modulesystem/Requirement.cpp

@@ -0,0 +1,19 @@
+/* === This file is part of Calamares - <http://github.com/calamares> ===
+ *
+ *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+#include "Requirement.h"
+

src/libcalamaresui/modulesystem/Requirement.h

@@ -0,0 +1,64 @@
+/* === This file is part of Calamares - <http://github.com/calamares> ===
+ *
+ *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef CALAMARES_REQUIREMENT_H
+#define CALAMARES_REQUIREMENT_H
+
+#include <QList>
+#include <QMetaType>
+#include <QString>
+
+#include <functional>
+
+namespace Calamares
+{
+
+/**
+ * An indication of a requirement, which is checked in preparation
+ * for system installation. An entry has a name and some explanation functions
+ * (functions, because they need to respond to translations).
+ *
+ * A requirement can be *satisfied* or not.
+ * A requirement can be optional (i.e. a "good to have") or mandatory.
+ *
+ * Requirements which are not satisfied, and also mandatory, will prevent the
+ * installation from proceeding.
+ */
+struct RequirementEntry
+{
+    using TextFunction = std::function< QString() >;
+
+    /// @brief name of this requirement; not shown to user and used as ID
+    QString name;
+
+    /// @brief Description of this requirement, for use in user-visible lists
+    TextFunction enumerationText;
+
+    /// @brief User-visible string to show that the requirement is not met
+    TextFunction negatedText;
+
+    bool satisfied;
+    bool mandatory;
+};
+
+using RequirementsList = QList< RequirementEntry >;
+
+}  // namespace Calamares
+
+Q_DECLARE_METATYPE(Calamares::RequirementEntry)
+
+#endif

src/libcalamaresui/modulesystem/RequirementsChecker.cpp

@@ -0,0 +1,154 @@
+/* === This file is part of Calamares - <http://github.com/calamares> ===
+ *
+ *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "RequirementsChecker.h"
+
+#include "Module.h"
+#include "Requirement.h"
+
+#include "utils/Logger.h"
+
+#include <algorithm>
+
+#include <QtConcurrent/QtConcurrent>
+#include <QFuture>
+#include <QFutureWatcher>
+#include <QTimer>
+
+
+namespace Calamares
+{
+
+static void
+registerMetatypes()
+{
+    static bool done = false;
+
+    if ( !done )
+    {
+        qRegisterMetaType< RequirementEntry >( "RequirementEntry" );
+        // It's sensitive to the names of types in parameters; in particular
+        // althrough QList<RequirementEntry> is the same as RequirementsList,
+        // because we *name* the type as  RequirementsList in the parameters,
+        // we need to register that (as well). Here, be safe and register
+        // both names.
+        qRegisterMetaType< QList< RequirementEntry > >( "QList<RequirementEntry>" );
+        qRegisterMetaType< RequirementsList >( "RequirementsList" );
+        done = true;
+    }
+}
+
+static void
+check( Module * const &m, RequirementsChecker *c )
+{
+    RequirementsList l = m->checkRequirements();
+    if ( l.count() > 0 )
+        c->addCheckedRequirements( l );
+    c->requirementsProgress( QObject::tr( "Requirements checking for module <i>%1</i> is complete." ).arg( m->name() ) );
+}
+
+RequirementsChecker::RequirementsChecker( QVector< Module* > modules, QObject* parent )
+    : QObject( parent )
+    , m_modules( std::move( modules ) )
+    , m_progressTimer( nullptr )
+    , m_progressTimeouts( 0 )
+{
+    m_watchers.reserve( m_modules.count() );
+    m_collectedRequirements.reserve( m_modules.count() );
+
+    registerMetatypes();
+}
+
+RequirementsChecker::~RequirementsChecker()
+{
+}
+
+void
+RequirementsChecker::run()
+{
+    m_progressTimer = new QTimer( this );
+    connect( m_progressTimer, &QTimer::timeout, this, &RequirementsChecker::reportProgress );
+    m_progressTimer->start( 1200 );  // msec
+
+    for (const auto& module : m_modules )
+    {
+        Watcher *watcher = new Watcher( this );
+        watcher->setFuture( QtConcurrent::run( check, module, this ) );
+        m_watchers.append( watcher );
+        connect( watcher, &Watcher::finished, this, &RequirementsChecker::finished );
+    }
+
+    QTimer::singleShot( 0, this, &RequirementsChecker::finished );
+}
+
+void
+RequirementsChecker::finished()
+{
+    if ( std::all_of( m_watchers.cbegin(), m_watchers.cend(), []( const Watcher *w ) { return w && w->isFinished(); } ) )
+    {
+        cDebug() << "All requirements have been checked.";
+
+        if ( m_progressTimer )
+            m_progressTimer->stop();
+
+        bool acceptable = true;
+        int count = 0;
+        for ( const auto& r : m_collectedRequirements )
+        {
+            if ( r.mandatory && !r.satisfied )
+            {
+                cDebug() << "  .. requirement" << count << r.name << "is not satisfied.";
+                acceptable = false;
+            }
+            ++count;
+        }
+
+        emit requirementsComplete( acceptable );
+        QTimer::singleShot(0, this, &RequirementsChecker::done );
+    }
+}
+
+void
+RequirementsChecker::addCheckedRequirements( RequirementsList l )
+{
+    static QMutex addMutex;
+    {
+        QMutexLocker lock( &addMutex );
+        m_collectedRequirements.append( l );
+    }
+    cDebug() << "Added" << l.count() << "requirement results";
+    emit requirementsResult( l );
+}
+
+void
+RequirementsChecker::reportProgress()
+{
+    m_progressTimeouts++;
+
+    auto remaining = std::count_if( m_watchers.cbegin(), m_watchers.cend(), []( const Watcher *w ) { return w && !w->isFinished(); } );
+    if ( remaining > 0 )
+    {
+        QString waiting = tr( "Waiting for %n module(s).", "", remaining );
+        QString elapsed = tr( "(%n second(s))", "", m_progressTimeouts * m_progressTimer->interval() / 1000 );
+        emit requirementsProgress( waiting + QString( " " ) + elapsed );
+    }
+    else
+        emit requirementsProgress( tr( "System-requirements checking is complete." ) );
+}
+
+}

src/libcalamaresui/modulesystem/RequirementsChecker.h

@@ -0,0 +1,87 @@
+/* === This file is part of Calamares - <http://github.com/calamares> ===
+ *
+ *   Copyright 2019, Adriaan de Groot <groot@kde.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef CALAMARES_REQUIREMENTSCHECKER_H
+#define CALAMARES_REQUIREMENTSCHECKER_H
+
+#include "Requirement.h"
+
+#include <QFutureWatcher>
+#include <QObject>
+#include <QTimer>
+#include <QVector>
+
+
+namespace Calamares
+{
+
+class Module;
+
+/** @brief A manager-class that checks all the module requirements
+ *
+ * Asynchronously checks the requirements for each module, and
+ * emits progress signals as appropriate.
+ */
+class RequirementsChecker : public QObject
+{
+    Q_OBJECT
+
+public:
+    RequirementsChecker( QVector< Module* > modules, QObject* parent = nullptr );
+    virtual ~RequirementsChecker() override;
+
+public slots:
+    /// @brief Start checking all the requirements
+    void run();
+
+    /// @brief Called when requirements are reported by a module
+    void addCheckedRequirements( RequirementsList );
+
+    /// @brief Called when all requirements have been checked
+    void finished();
+
+    /// @brief Called periodically while requirements are being checked
+    void reportProgress();
+
+signals:
+    /// @brief Human-readable progress message
+    void requirementsProgress( const QString& );
+    /// @brief Requirements from a single module
+    void requirementsResult( RequirementsList );
+    /** @brief When all requirements are collected
+     *
+     * The argument indicates if all mandatory requirements are satisfied.
+     */
+    void requirementsComplete( bool );
+    /// @brief Emitted after requirementsComplete
+    void done();
+
+private:
+    QVector< Module* > m_modules;
+
+    using Watcher = QFutureWatcher< void >;
+    QVector< Watcher* > m_watchers;
+
+    RequirementsList m_collectedRequirements;
+
+    QTimer *m_progressTimer;
+    unsigned m_progressTimeouts;
+} ;
+
+}
+
+#endif

src/libcalamaresui/modulesystem/ViewModule.cpp

@@ -132,4 +132,10 @@ ViewModule::~ViewModule()
     delete m_loader;
 }
 
+RequirementsList
+ViewModule::checkRequirements()
+{
+    return m_viewStep->checkRequirements();
+}
+
 } // namespace Calamares

src/libcalamaresui/modulesystem/ViewModule.h

@@ -39,6 +39,8 @@ public:
     void loadSelf() override;
     JobList jobs() const override;
 
+    RequirementsList checkRequirements() override;
+
 protected:
     void initFrom( const QVariantMap& moduleDescriptor ) override;
 

src/libcalamaresui/viewpages/ViewStep.cpp

@@ -74,4 +74,10 @@ ViewStep::setConfigurationMap( const QVariantMap& configurationMap )
     Q_UNUSED( configurationMap );
 }
 
+
+RequirementsList ViewStep::checkRequirements()
+{
+    return RequirementsList();
+}
+
 }

src/libcalamaresui/viewpages/ViewStep.h

@@ -22,6 +22,7 @@
 
 #include <QObject>
 
+#include "modulesystem/Requirement.h"
 #include "../UiDllMacro.h"
 #include "Typedefs.h"
 
@@ -117,6 +118,12 @@ public:
      */
     virtual void onLeave();
 
+    /**
+     * @brief Jobs needed to run this viewstep
+     *
+     * When a ViewStep is listed in the exec section, its jobs are executed instead.
+     * This function returns that list of jobs; an empty list is ok.
+     */
     virtual JobList jobs() const = 0;
 
     void setModuleInstanceKey( const QString& instanceKey );
@@ -127,7 +134,17 @@ public:
 
     virtual void setConfigurationMap( const QVariantMap& configurationMap );
 
+    /**
+     * @brief Can this module proceed, on this machine?
+     *
+     * This is called asynchronously at startup, and returns a list of
+     * the requirements that the module has checked, and their status.
+     * See Calamares::RequirementEntry for details.
+     */
+    virtual RequirementsList checkRequirements();
+
 signals:
+    /// @brief Tells the viewmanager to enable the *next* button according to @p status
     void nextStatusChanged( bool status );
 
     /* Emitted when the viewstep thinks it needs more space than is currently

src/modules/partition/gui/ChoicePage.cpp

@@ -882,11 +882,6 @@ ChoicePage::updateDeviceStatePreview()
     PartitionModel* model = new PartitionModel( m_beforePartitionBarsView );
     model->init( deviceBefore, m_core->osproberEntries() );
 
-    // The QObject parents tree is meaningful for memory management here,
-    // see qDeleteAll above.
-    deviceBefore->setParent( model );  // Can't reparent across threads
-    model->setParent( m_beforePartitionBarsView );
-
     m_beforePartitionBarsView->setModel( model );
     m_beforePartitionLabelsView->setModel( model );
 

src/modules/partition/gui/PartitionViewStep.cpp

@@ -60,6 +60,8 @@
 #include <QtConcurrent/QtConcurrent>
 #include <QFutureWatcher>
 
+#include <unistd.h>  // For sleep(3)
+
 PartitionViewStep::PartitionViewStep( QObject* parent )
     : Calamares::ViewStep( parent )
     , m_core( nullptr )
@@ -584,17 +586,18 @@ PartitionViewStep::setConfigurationMap( const QVariantMap& configurationMap )
     // Now that we have the config, we load the PartitionCoreModule in the background
     // because it could take a while. Then when it's done, we can set up the widgets
     // and remove the spinner.
-    QFutureWatcher< void >* watcher = new QFutureWatcher< void >();
+    m_future = new QFutureWatcher< void >();
-    connect( watcher, &QFutureWatcher< void >::finished,
+    connect( m_future, &QFutureWatcher< void >::finished,
-             this, [ this, watcher, choices ]
+             this, [ this ]
     {
         continueLoading();
-        watcher->deleteLater();
+        this->m_future->deleteLater();
+        this->m_future = nullptr;
     } );
 
     QFuture< void > future =
         QtConcurrent::run( this, &PartitionViewStep::initPartitionCoreModule );
-    watcher->setFuture( future );
+    m_future->setFuture( future );
 
     if ( configurationMap.contains( "partitionLayout" ) )
     {
@@ -613,5 +616,24 @@ PartitionViewStep::jobs() const
     return m_core->jobs();
 }
 
+Calamares::RequirementsList
+PartitionViewStep::checkRequirements()
+{
+    if ( m_future )
+        m_future->waitForFinished();
+
+    Calamares::RequirementsList l;
+    l.append(
+    {
+        QLatin1Literal( "partitions" ),
+        []{ return tr( "has at least one disk device available." ); },
+        []{ return tr( "There are no partitons to install on." ); },
+        m_core->deviceModel()->rowCount() > 0,  // satisfied
+        true    // required
+    } );
+
+    return l;
+}
+
 
 CALAMARES_PLUGIN_FACTORY_DEFINITION( PartitionViewStepFactory, registerPlugin<PartitionViewStep>(); )

src/modules/partition/gui/PartitionViewStep.h

@@ -36,6 +36,8 @@ class PartitionPage;
 class PartitionCoreModule;
 class QStackedWidget;
 
+template<typename T> class QFutureWatcher;
+
 /**
  * The starting point of the module. Instantiates PartitionCoreModule,
  * ChoicePage and PartitionPage, then connects them.
@@ -69,6 +71,8 @@ public:
 
     QList< Calamares::job_ptr > jobs() const override;
 
+    Calamares::RequirementsList checkRequirements() override;
+
 private:
     void initPartitionCoreModule();
     void continueLoading();
@@ -79,6 +83,7 @@ private:
     PartitionPage*    m_manualPartitionPage;
 
     QWidget*          m_waitingWidget;
+    QFutureWatcher<void>* m_future;
 
     QSet< PartitionActions::Choices::SwapChoice > m_swapChoices;
 };

src/modules/welcome/CMakeLists.txt

@@ -15,9 +15,10 @@ endif()
 include_directories( ${PROJECT_BINARY_DIR}/src/libcalamaresui )
 
 set( CHECKER_SOURCES
-    checker/CheckItemWidget.cpp
+    checker/CheckerContainer.cpp
     checker/CheckerWidget.cpp
-    checker/RequirementsChecker.cpp
+    checker/CheckItemWidget.cpp
+    checker/GeneralRequirements.cpp
     ${PARTMAN_SRC}
 )
 

src/modules/welcome/WelcomePage.cpp

@@ -22,10 +22,12 @@
 
 #include "ui_WelcomePage.h"
 #include "CalamaresVersion.h"
-#include "checker/RequirementsChecker.h"
+#include "checker/CheckerContainer.h"
 #include "utils/Logger.h"
 #include "utils/CalamaresUtilsGui.h"
 #include "utils/Retranslator.h"
+
+#include "modulesystem/ModuleManager.h"
 #include "ViewManager.h"
 
 #include <QApplication>
@@ -39,11 +41,14 @@
 #include "Branding.h"
 
 
-WelcomePage::WelcomePage( RequirementsChecker* requirementsChecker, QWidget* parent )
+WelcomePage::WelcomePage( QWidget* parent )
     : QWidget( parent )
     , ui( new Ui::WelcomePage )
-    , m_requirementsChecker( requirementsChecker )
+    , m_checkingWidget( new CheckerContainer( this ) )
 {
+    connect( Calamares::ModuleManager::instance(), &Calamares::ModuleManager::requirementsResult, m_checkingWidget, &CheckerContainer::requirementsChecked );
+    connect( Calamares::ModuleManager::instance(), &Calamares::ModuleManager::requirementsComplete, m_checkingWidget, &CheckerContainer::requirementsComplete );
+    connect( Calamares::ModuleManager::instance(), &Calamares::ModuleManager::requirementsProgress, m_checkingWidget, &CheckerContainer::requirementsProgress );
     ui->setupUi( this );
 
     ui->verticalLayout->insertSpacing( 1, CalamaresUtils::defaultFontHeight() * 2 );
@@ -102,7 +107,7 @@ WelcomePage::WelcomePage( RequirementsChecker* requirementsChecker, QWidget* par
         mb.exec();
     } );
 
-    ui->verticalLayout->insertWidget( 3, m_requirementsChecker->widget() );
+    ui->verticalLayout->insertWidget( 3, m_checkingWidget);
 }
 
 
@@ -277,3 +282,8 @@ WelcomePage::focusInEvent( QFocusEvent* e )
         ui->languageWidget->setFocus();
     e->accept();
 }
+
+bool WelcomePage::verdict() const
+{
+    return m_checkingWidget->verdict();
+}

src/modules/welcome/WelcomePage.h

@@ -26,26 +26,27 @@ namespace Ui
 class WelcomePage;
 }
 
-class RequirementsChecker;
+class CheckerContainer;
 
 class WelcomePage : public QWidget
 {
     Q_OBJECT
 public:
-    explicit WelcomePage( RequirementsChecker* requirementsChecker,
+    explicit WelcomePage( QWidget* parent = nullptr );
-                          QWidget* parent = nullptr );
 
     void setUpLinks( bool showSupportUrl,
                      bool showKnownIssuesUrl,
                      bool showReleaseNotesUrl );
 
+    bool verdict() const;
+
 protected:
     void focusInEvent( QFocusEvent* e ) override; //choose the child widget to focus
 
 private:
     void initLanguages();
     Ui::WelcomePage* ui;
-    RequirementsChecker* m_requirementsChecker;
+    CheckerContainer* m_checkingWidget;
 };
 
 #endif // WELCOMEPAGE_H

src/modules/welcome/WelcomeViewStep.cpp

@@ -20,9 +20,10 @@
 #include "WelcomeViewStep.h"
 
 #include "WelcomePage.h"
-#include "checker/RequirementsChecker.h"
+#include "checker/GeneralRequirements.h"
-#include "utils/Logger.h"
 
+#include "modulesystem/ModuleManager.h"
+#include "utils/Logger.h"
 
 #include <QVariant>
 
@@ -30,12 +31,10 @@ CALAMARES_PLUGIN_FACTORY_DEFINITION( WelcomeViewStepFactory, registerPlugin<Welc
 
 WelcomeViewStep::WelcomeViewStep( QObject* parent )
     : Calamares::ViewStep( parent )
-    , m_requirementsChecker( new RequirementsChecker( this ) )
+    , m_requirementsChecker( new GeneralRequirements( this ) )
 {
-    emit nextStatusChanged( true );
+    connect( Calamares::ModuleManager::instance(), &Calamares::ModuleManager::requirementsComplete, this, &WelcomeViewStep::nextStatusChanged );
-    m_widget = new WelcomePage( m_requirementsChecker );
+    m_widget = new WelcomePage();
-    connect( m_requirementsChecker, &RequirementsChecker::verdictChanged,
-             this, &WelcomeViewStep::nextStatusChanged );
 }
 
 
@@ -63,7 +62,7 @@ WelcomeViewStep::widget()
 bool
 WelcomeViewStep::isNextEnabled() const
 {
-    return m_requirementsChecker->verdict();
+    return m_widget->verdict();
 }
 
 
@@ -88,10 +87,10 @@ WelcomeViewStep::isAtEnd() const
 }
 
 
-QList< Calamares::job_ptr >
+Calamares::JobList
 WelcomeViewStep::jobs() const
 {
-    return QList< Calamares::job_ptr >();
+    return Calamares::JobList();
 }
 
 
@@ -123,3 +122,7 @@ WelcomeViewStep::setConfigurationMap( const QVariantMap& configurationMap )
                     "module configuration.";
 }
 
+Calamares::RequirementsList WelcomeViewStep::checkRequirements()
+{
+    return m_requirementsChecker->checkRequirements();
+}

src/modules/welcome/WelcomeViewStep.h

@@ -21,6 +21,7 @@
 
 #include <QObject>
 
+#include <modulesystem/Requirement.h>
 #include <utils/PluginFactory.h>
 #include <viewpages/ViewStep.h>
 
@@ -29,7 +30,7 @@
 #include <QVariantMap>
 
 class WelcomePage;
-class RequirementsChecker;
+class GeneralRequirements;
 
 class PLUGINDLLEXPORT WelcomeViewStep : public Calamares::ViewStep
 {
@@ -49,14 +50,15 @@ public:
     bool isAtBeginning() const override;
     bool isAtEnd() const override;
 
-    QList< Calamares::job_ptr > jobs() const override;
+    Calamares::JobList jobs() const override;
 
     void setConfigurationMap( const QVariantMap& configurationMap ) override;
 
+    Calamares::RequirementsList checkRequirements() override;
+
 private:
     WelcomePage* m_widget;
-
+    GeneralRequirements* m_requirementsChecker;
-    RequirementsChecker* m_requirementsChecker;
 };
 
 CALAMARES_PLUGIN_FACTORY_DECLARATION( WelcomeViewStepFactory )

src/modules/welcome/checker/CheckerContainer.cpp

@@ -0,0 +1,78 @@
+/* === This file is part of Calamares - <https://github.com/calamares> ===
+ *
+ *   Copyright 2014-2017, Teo Mrnjavac <teo@kde.org>
+ *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2017, Gabriel Craciunescu <crazy@frugalware.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Based on code extracted from RequirementsChecker.cpp */
+
+#include "CheckerContainer.h"
+
+#include "CheckerWidget.h"
+
+#include "utils/CalamaresUtilsGui.h"
+#include "utils/Logger.h"
+#include "utils/Retranslator.h"
+#include "widgets/WaitingWidget.h"
+
+CheckerContainer::CheckerContainer(QWidget* parent)
+    : QWidget( parent )
+    , m_waitingWidget( new WaitingWidget( QString() ) )
+    , m_checkerWidget( new CheckerWidget() )
+    , m_verdict( false )
+{
+    QBoxLayout* mainLayout = new QHBoxLayout;
+    setLayout( mainLayout );
+    CalamaresUtils::unmarginLayout( mainLayout );
+
+    mainLayout->addWidget( m_waitingWidget );
+    CALAMARES_RETRANSLATE( m_waitingWidget->setText( tr( "Gathering system information..." ) ); )
+}
+
+CheckerContainer::~CheckerContainer()
+{
+    delete m_waitingWidget;
+    delete m_checkerWidget;
+}
+
+void CheckerContainer::requirementsComplete( bool ok )
+{
+    m_checkerWidget->init( m_requirements );
+    layout()->removeWidget( m_waitingWidget );
+    m_waitingWidget->deleteLater();
+    m_waitingWidget = nullptr;  // Don't delete in destructor
+    m_checkerWidget->setParent( this );
+    layout()->addWidget( m_checkerWidget );
+
+    m_verdict = ok;
+}
+
+void CheckerContainer::requirementsChecked(const Calamares::RequirementsList& l)
+{
+    m_requirements.append( l );
+}
+
+void CheckerContainer::requirementsProgress(const QString& message)
+{
+    if ( m_waitingWidget )
+        m_waitingWidget->setText( message );
+}
+
+bool CheckerContainer::verdict() const
+{
+    return m_verdict;
+}

src/modules/welcome/checker/CheckerContainer.h

@@ -0,0 +1,64 @@
+/* === This file is part of Calamares - <https://github.com/calamares> ===
+ *
+ *   Copyright 2014-2017, Teo Mrnjavac <teo@kde.org>
+ *   Copyright 2017, Adriaan de Groot <groot@kde.org>
+ *   Copyright 2017, Gabriel Craciunescu <crazy@frugalware.org>
+ *
+ *   Calamares is free software: you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, either version 3 of the License, or
+ *   (at your option) any later version.
+ *
+ *   Calamares 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Based on code extracted from RequirementsChecker.cpp */
+
+#ifndef CHECKERCONTAINER_H
+#define CHECKERCONTAINER_H
+
+#include <QWidget>
+
+#include "modulesystem/Requirement.h"
+
+class CheckerWidget;
+class WaitingWidget;
+
+/**
+ * A widget that collects requirements results; until the results are
+ * all in, displays a spinner / waiting widget. Then it switches to
+ * a (list) diplay of the results, plus some explanation of the
+ * overall state of the entire list of results.
+ */
+class CheckerContainer : public QWidget
+{
+    Q_OBJECT
+public:
+    explicit CheckerContainer( QWidget* parent = nullptr );
+    virtual ~CheckerContainer();
+
+    bool verdict() const;
+
+public slots:
+    void requirementsChecked( const Calamares::RequirementsList& );
+
+    /** @brief All the requirements are complete, switch to list view */
+    void requirementsComplete( bool );
+
+    void requirementsProgress( const QString& message );
+
+protected:
+    WaitingWidget *m_waitingWidget;
+    CheckerWidget *m_checkerWidget;
+
+    Calamares::RequirementsList m_requirements;
+    bool m_verdict;
+} ;
+
+#endif

src/modules/welcome/checker/CheckerWidget.cpp

@@ -53,22 +53,22 @@ CheckerWidget::CheckerWidget( QWidget* parent )
 
 
 void
-CheckerWidget::init( const QList< PrepareEntry >& checkEntries )
+CheckerWidget::init( const Calamares::RequirementsList& checkEntries )
 {
     bool allChecked = true;
     bool requirementsSatisfied = true;
 
-    for ( const PrepareEntry& entry : checkEntries )
+    for ( const auto& entry : checkEntries )
     {
-        if ( !entry.checked )
+        if ( !entry.satisfied )
         {
-            CheckItemWidget* ciw = new CheckItemWidget( entry.checked, entry.required );
+            CheckItemWidget* ciw = new CheckItemWidget( entry.satisfied, entry.mandatory );
             CALAMARES_RETRANSLATE( ciw->setText( entry.negatedText() ); )
             m_entriesLayout->addWidget( ciw );
             ciw->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Preferred );
 
             allChecked = false;
-            if ( entry.required )
+            if ( entry.mandatory )
             {
                 requirementsSatisfied = false;
             }
@@ -162,7 +162,7 @@ CheckerWidget::init( const QList< PrepareEntry >& checkEntries )
 
 
 void
-CheckerWidget::showDetailsDialog( const QList< PrepareEntry >& checkEntries )
+CheckerWidget::showDetailsDialog( const Calamares::RequirementsList& checkEntries )
 {
     QDialog* detailsDialog = new QDialog( this );
     QBoxLayout* mainLayout = new QVBoxLayout;
@@ -177,12 +177,12 @@ CheckerWidget::showDetailsDialog( const QList< PrepareEntry >& checkEntries )
     CalamaresUtils::unmarginLayout( entriesLayout );
     mainLayout->addLayout( entriesLayout );
 
-    for ( const PrepareEntry& entry : checkEntries )
+    for ( const auto& entry : checkEntries )
     {
         if ( entry.enumerationText().isEmpty() )
             continue;
 
-        CheckItemWidget* ciw = new CheckItemWidget( entry.checked, entry.required );
+        CheckItemWidget* ciw = new CheckItemWidget( entry.satisfied, entry.mandatory );
         CALAMARES_RETRANSLATE( ciw->setText( entry.enumerationText() ); )
         entriesLayout->addWidget( ciw );
         ciw->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Preferred );

src/modules/welcome/checker/CheckerWidget.h

@@ -19,7 +19,7 @@
 #ifndef CHECKERWIDGET_H
 #define CHECKERWIDGET_H
 
-#include "RequirementsChecker.h"
+#include "modulesystem/Requirement.h"
 
 #include <QBoxLayout>
 #include <QWidget>
@@ -30,10 +30,10 @@ class CheckerWidget : public QWidget
 public:
     explicit CheckerWidget( QWidget* parent = nullptr );
 
-    void init( const QList< PrepareEntry >& checkEntries );
+    void init( const Calamares::RequirementsList& checkEntries );
 
 private:
-    void showDetailsDialog( const QList< PrepareEntry >& checkEntries );
+    void showDetailsDialog( const Calamares::RequirementsList& checkEntries );
 
     QBoxLayout* m_mainLayout;
     QBoxLayout* m_entriesLayout;

src/modules/welcome/checker/GeneralRequirements.cpp

@@ -18,11 +18,12 @@
  *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "RequirementsChecker.h"
+#include "GeneralRequirements.h"
 
-#include "CheckerWidget.h"
+#include "CheckerContainer.h"
 #include "partman_devices.h"
 
+#include "modulesystem/Requirement.h"
 #include "widgets/WaitingWidget.h"
 #include "utils/CalamaresUtilsGui.h"
 #include "utils/Logger.h"
@@ -30,6 +31,7 @@
 #include "utils/CalamaresUtilsSystem.h"
 #include "utils/Units.h"
 
+
 #include "JobQueue.h"
 #include "GlobalStorage.h"
 
@@ -51,29 +53,17 @@
 
 #include <unistd.h> //geteuid
 
-RequirementsChecker::RequirementsChecker( QObject* parent )
+GeneralRequirements::GeneralRequirements( QObject* parent )
     : QObject( parent )
-    , m_widget( new QWidget() )
     , m_requiredStorageGB( -1 )
     , m_requiredRamGB( -1 )
-    , m_actualWidget( new CheckerWidget() )
-    , m_verdict( false )
 {
-    QBoxLayout* mainLayout = new QHBoxLayout;
+}
-    m_widget->setLayout( mainLayout );
-    CalamaresUtils::unmarginLayout( mainLayout );
 
-    WaitingWidget* waitingWidget = new WaitingWidget( QString() );
+Calamares::RequirementsList GeneralRequirements::checkRequirements()
-    mainLayout->addWidget( waitingWidget );
-    CALAMARES_RETRANSLATE( waitingWidget->setText( tr( "Gathering system information..." ) ); )
-
-    QSize availableSize = qApp->desktop()->availableGeometry( m_widget ).size();
-
-    QTimer* timer = new QTimer;
-    timer->setSingleShot( true );
-    connect( timer, &QTimer::timeout,
-             [=]()
 {
+    QSize availableSize = qApp->desktop()->availableGeometry().size();
+
     bool enoughStorage = false;
     bool enoughRam = false;
     bool hasPower = false;
@@ -101,15 +91,14 @@ RequirementsChecker::RequirementsChecker( QObject* parent )
         isRoot = checkIsRoot();
 
     using TR = Logger::DebugRow<const char *, bool>;
-
+    cDebug() << "GeneralRequirements output:"
-        cDebug() << "RequirementsChecker output:"
                     << TR("enoughStorage", enoughStorage)
                     << TR("enoughRam", enoughRam)
                     << TR("hasPower", hasPower)
                     << TR("hasInternet", hasInternet)
                     << TR("isRoot", isRoot);
 
-        QList< PrepareEntry > checkEntries;
+    Calamares::RequirementsList checkEntries;
     foreach ( const QString& entry, m_entriesToCheck )
     {
         if ( entry == "storage" )
@@ -165,52 +154,12 @@ RequirementsChecker::RequirementsChecker( QObject* parent )
                 false
             } );
     }
-
+    return checkEntries;
-        m_actualWidget->init( checkEntries );
-        m_widget->layout()->removeWidget( waitingWidget );
-        waitingWidget->deleteLater();
-        m_actualWidget->setParent( m_widget );
-        m_widget->layout()->addWidget( m_actualWidget );
-
-        bool canGoNext = true;
-        foreach ( const PrepareEntry& entry, checkEntries )
-        {
-            if ( !entry.checked && entry.required )
-            {
-                canGoNext = false;
-                break;
-            }
-        }
-        m_verdict = canGoNext;
-        emit verdictChanged( m_verdict );
-
-        if ( canGoNext )
-            detectFirmwareType();
-
-        timer->deleteLater();
-    } );
-    timer->start( 0 );
-
-    emit verdictChanged( true );
-}
-
-
-RequirementsChecker::~RequirementsChecker()
-{
-    if ( m_widget && m_widget->parent() == nullptr )
-        m_widget->deleteLater();
-}
-
-
-QWidget*
-RequirementsChecker::widget() const
-{
-    return m_widget;
 }
 
 
 void
-RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
+GeneralRequirements::setConfigurationMap( const QVariantMap& configurationMap )
 {
     bool incompleteConfiguration = false;
 
@@ -222,7 +171,7 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
     }
     else
     {
-        cWarning() << "RequirementsChecker entry 'check' is incomplete.";
+        cWarning() << "GeneralRequirements entry 'check' is incomplete.";
         incompleteConfiguration = true;
     }
 
@@ -234,14 +183,26 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
     }
     else
     {
-        cWarning() << "RequirementsChecker entry 'required' is incomplete.";
+        cWarning() << "GeneralRequirements entry 'required' is incomplete.";
         incompleteConfiguration = true;
     }
 
+#ifdef WITHOUT_LIBPARTED
+    if ( m_entriesToCheck.contains( "storage" ) )
+        cWarning() << "GeneralRequirements checks 'storage' but libparted is disabled.";
+    if ( m_entriesToRequire.contains( "storage" ) )
+    {
+        // Warn, but also drop the required bit because otherwise installation
+        // will be impossible (because the check always returns false).
+        cWarning() << "GeneralRequirements requires 'storage' check but libparted is disabled.";
+        m_entriesToRequire.removeAll( "storage" );
+    }
+#endif
+
     // Help out with consistency, but don't fix
     for ( const auto& r : m_entriesToRequire )
         if ( !m_entriesToCheck.contains( r ) )
-            cWarning() << "RequirementsChecker requires" << r << "but does not check it.";
+            cWarning() << "GeneralRequirements requires" << r << "but does not check it.";
 
     if ( configurationMap.contains( "requiredStorage" ) &&
          ( configurationMap.value( "requiredStorage" ).type() == QVariant::Double ||
@@ -251,7 +212,7 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
         m_requiredStorageGB = configurationMap.value( "requiredStorage" ).toDouble( &ok );
         if ( !ok )
         {
-            cWarning() << "RequirementsChecker entry 'requiredStorage' is invalid.";
+            cWarning() << "GeneralRequirements entry 'requiredStorage' is invalid.";
             m_requiredStorageGB = 3.;
         }
 
@@ -259,7 +220,7 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
     }
     else
     {
-        cWarning() << "RequirementsChecker entry 'requiredStorage' is missing.";
+        cWarning() << "GeneralRequirements entry 'requiredStorage' is missing.";
         m_requiredStorageGB = 3.;
         incompleteConfiguration = true;
     }
@@ -272,14 +233,14 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
         m_requiredRamGB = configurationMap.value( "requiredRam" ).toDouble( &ok );
         if ( !ok )
         {
-            cWarning() << "RequirementsChecker entry 'requiredRam' is invalid.";
+            cWarning() << "GeneralRequirements entry 'requiredRam' is invalid.";
             m_requiredRamGB = 1.;
             incompleteConfiguration = true;
         }
     }
     else
     {
-        cWarning() << "RequirementsChecker entry 'requiredRam' is missing.";
+        cWarning() << "GeneralRequirements entry 'requiredRam' is missing.";
         m_requiredRamGB = 1.;
         incompleteConfiguration = true;
     }
@@ -291,7 +252,7 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
         if ( m_checkHasInternetUrl.isEmpty() ||
              !QUrl( m_checkHasInternetUrl ).isValid() )
         {
-            cWarning() << "RequirementsChecker entry 'internetCheckUrl' is invalid in welcome.conf" << m_checkHasInternetUrl
+            cWarning() << "GeneralRequirements entry 'internetCheckUrl' is invalid in welcome.conf" << m_checkHasInternetUrl
                      << "reverting to default (http://example.com).";
             m_checkHasInternetUrl = "http://example.com";
             incompleteConfiguration = true;
@@ -299,7 +260,7 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
     }
     else
     {
-        cWarning() << "RequirementsChecker entry 'internetCheckUrl' is undefined in welcome.conf,"
+        cWarning() << "GeneralRequirements entry 'internetCheckUrl' is undefined in welcome.conf,"
                     "reverting to default (http://example.com).";
 
         m_checkHasInternetUrl = "http://example.com";
@@ -308,24 +269,17 @@ RequirementsChecker::setConfigurationMap( const QVariantMap& configurationMap )
 
     if ( incompleteConfiguration )
     {
-        cWarning() << "RequirementsChecker configuration map:" << Logger::DebugMap( configurationMap );
+        cWarning() << "GeneralRequirements configuration map:" << Logger::DebugMap( configurationMap );
     }
 }
 
 
 bool
-RequirementsChecker::verdict() const
+GeneralRequirements::checkEnoughStorage( qint64 requiredSpace )
-{
-    return m_verdict;
-}
-
-
-bool
-RequirementsChecker::checkEnoughStorage( qint64 requiredSpace )
 {
 #ifdef WITHOUT_LIBPARTED
     Q_UNUSED( requiredSpace );
-    cWarning() << "RequirementsChecker is configured without libparted.";
+    cWarning() << "GeneralRequirements is configured without libparted.";
     return false;
 #else
     return check_big_enough( requiredSpace );
@@ -334,7 +288,7 @@ RequirementsChecker::checkEnoughStorage( qint64 requiredSpace )
 
 
 bool
-RequirementsChecker::checkEnoughRam( qint64 requiredRam )
+GeneralRequirements::checkEnoughRam( qint64 requiredRam )
 {
     // Ignore the guesstimate-factor; we get an under-estimate
     // which is probably the usable RAM for programs.
@@ -344,7 +298,7 @@ RequirementsChecker::checkEnoughRam( qint64 requiredRam )
 
 
 bool
-RequirementsChecker::checkBatteryExists()
+GeneralRequirements::checkBatteryExists()
 {
     const QFileInfo basePath( "/sys/class/power_supply" );
 
@@ -370,7 +324,7 @@ RequirementsChecker::checkBatteryExists()
 
 
 bool
-RequirementsChecker::checkHasPower()
+GeneralRequirements::checkHasPower()
 {
     const QString UPOWER_SVC_NAME( "org.freedesktop.UPower" );
     const QString UPOWER_INTF_NAME( "org.freedesktop.UPower" );
@@ -401,10 +355,10 @@ RequirementsChecker::checkHasPower()
 
 
 bool
-RequirementsChecker::checkHasInternet()
+GeneralRequirements::checkHasInternet()
 {
     // default to true in the QNetworkAccessManager::UnknownAccessibility case
-    QNetworkAccessManager qnam( this );
+    QNetworkAccessManager qnam;
     bool hasInternet = qnam.networkAccessible() == QNetworkAccessManager::Accessible;
 
     if ( !hasInternet && qnam.networkAccessible() == QNetworkAccessManager::UnknownAccessibility )
@@ -425,14 +379,14 @@ RequirementsChecker::checkHasInternet()
 
 
 bool
-RequirementsChecker::checkIsRoot()
+GeneralRequirements::checkIsRoot()
 {
     return !geteuid();
 }
 
 
 void
-RequirementsChecker::detectFirmwareType()
+GeneralRequirements::detectFirmwareType()
 {
     QString fwType = QFile::exists( "/sys/firmware/efi/efivars" ) ? "efi" : "bios";
     Calamares::JobQueue::instance()->globalStorage()->insert( "firmwareType", fwType );

src/modules/welcome/checker/GeneralRequirements.h

@@ -17,52 +17,23 @@
  *   along with Calamares. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef REQUIREMENTSCHECKER_H
+#ifndef GENERALREQUIREMENTS_H
-#define REQUIREMENTSCHECKER_H
+#define GENERALREQUIREMENTS_H
 
 #include <QObject>
 #include <QStringList>
 
-#include <functional>
+#include "modulesystem/Requirement.h"
 
-class CheckerWidget;
+class GeneralRequirements : public QObject
-class QWidget;
-
-/**
- * An indication of a requirement, which is checked in preparation
- * for system installation. An entry has a name and some explanation,
- * as well as three meaningful states:
- *  - checked = true, the requirement is met (green)
- *  - checked = false, the requirement is not met
- *      - required = false, warn about it (yellow), no failure
- *      - required = true, prohibit installation (red)
- */
-struct PrepareEntry
-{
-    QString name;
-    std::function< QString() > enumerationText; //Partial string, inserted in a
-                                                //list of requirements to satisfy.
-    std::function< QString() > negatedText;     //Complete sentence about this requirement
-                                                //not having been met.
-    bool checked;
-    bool required;
-};
-
-class RequirementsChecker : public QObject
 {
     Q_OBJECT
 public:
-    explicit RequirementsChecker( QObject* parent = nullptr );
+    explicit GeneralRequirements( QObject* parent = nullptr );
-    virtual ~RequirementsChecker();
-
-    QWidget* widget() const;
 
     void setConfigurationMap( const QVariantMap& configurationMap );
 
-    bool verdict() const;
+    Calamares::RequirementsList checkRequirements();
-
-signals:
-    void verdictChanged( bool );
 
 private:
     QStringList m_entriesToCheck;
@@ -76,13 +47,9 @@ private:
     bool checkIsRoot();
     void detectFirmwareType();
 
-    QWidget* m_widget;
     qreal m_requiredStorageGB;
     qreal m_requiredRamGB;
     QString m_checkHasInternetUrl;
-
-    CheckerWidget* m_actualWidget;
-    bool m_verdict;
 };
 
 #endif // REQUIREMENTSCHECKER_H

src/modules/welcome/welcome.conf

@@ -1,18 +1,37 @@
+# Configuration for the welcome module. The welcome page
+# displays some information from the branding file.
+# Which parts it displays can be configured through
+# the show* variables.
+#
+# In addition to displaying the welcome page, this module
+# can check requirements for installation.
 ---
+# Display settings for various buttons on the welcome page.
 showSupportUrl:         true
 showKnownIssuesUrl:     true
 showReleaseNotesUrl:    true
 
+# Requirements checking. These are general, generic, things
+# that are checked. They may not match with the actual requirements
+# imposed by other modules in the system.
 requirements:
+    # Amount of available disk, in GB. Floating-point is allowed here.
+    # Note that this does not account for *usable* disk, so it is possible
+    # to pass this requirement, yet have no space to install to.
     requiredStorage:    5.5
+
+    # Amount of available RAM, in GB. Floating-point is allowed here.
     requiredRam:        1.0
+
+    # To check for internet connectivity, Calamares does a HTTP GET
+    # on this URL; on success (e.g. HTTP code 200) internet is OK.
     internetCheckUrl:   http://google.com
 
     # List conditions to check. Each listed condition will be
     # probed in some way, and yields true or false according to
     # the host system satisfying the condition.
     #
-    # This sample file lists all the conditions that are know.
+    # This sample file lists all the conditions that are known.
     check:
         - storage
         - ram
@@ -20,7 +39,7 @@ requirements:
         - internet
         - root
         - screen
-    # List conditions that must be satisfied (from the list
+    # List conditions that **must** be satisfied (from the list
     # of conditions, above) for installation to proceed.
     # If any of these conditions are not met, the user cannot
     # continue past the welcome page.