Add an API (currently private) for installing missing Plasma engines.

Use it when a requested data or script engine is not found.

REVIEW: 102175

CMakeLists.txt

@@ -6,8 +6,13 @@ if(KDE_PLATFORM_FEATURE_BINARY_COMPATIBLE_FEATURE_REDUCTION)
     set(PLASMA_NO_KNEWSTUFF TRUE)
     set(PLASMA_NO_SOLID TRUE)
     set(PLASMA_NO_KIO TRUE)
+    set(PLASMA_NO_PACKAGEKIT TRUE)
 endif(KDE_PLATFORM_FEATURE_BINARY_COMPATIBLE_FEATURE_REDUCTION)
 
+if(NOT Q_WS_X11)
+    set(PLASMA_NO_PACKAGEKIT TRUE)
+endif(NOT Q_WS_X11)
+
 include_directories(${CMAKE_CURRENT_SOURCE_DIR}
                     ${KDE4_KDECORE_INCLUDES}
                     ${KDE4_KDEUI_INCLUDES}
@@ -42,6 +47,11 @@ if(NOT PLASMA_NO_SOLID)
     set(PLASMA_EXTRA_LIBS ${PLASMA_EXTRA_LIBS} ${KDE4_SOLID_LIBS})
 endif(NOT PLASMA_NO_SOLID)
 
+if(NOT PLASMA_NO_PACKAGEKIT)
+    add_definitions(-DPLASMA_ENABLE_PACKAGEKIT_SUPPORT=1)
+    set(PLASMA_EXTRA_LIBS ${PLASMA_EXTRA_LIBS} ${QT_QTDBUS_LIBRARY})
+endif(NOT PLASMA_NO_PACKAGEKIT)
+
 if(QCA2_FOUND)
     include_directories(${QCA2_INCLUDE_DIR})
     set(ENABLE_REMOTE_WIDGETS TRUE)
@@ -110,6 +120,7 @@ set(plasma_LIB_SRCS
     private/animablegraphicswebview.cpp
     private/applethandle.cpp
     private/associatedapplicationmanager.cpp
+    private/componentinstaller.cpp
     private/datacontainer_p.cpp
     private/dataenginebindings.cpp
     private/dataengineconsumer.cpp

dataenginemanager.cpp

@@ -29,6 +29,7 @@
 
 #include "datacontainer.h"
 #include "pluginloader.h"
+#include "private/componentinstaller_p.h"
 #include "private/dataengine_p.h"
 #include "private/datacontainer_p.h"
 #include "scripting/scriptengine.h"
@@ -130,6 +131,9 @@ Plasma::DataEngine *DataEngineManager::loadEngine(const QString &name)
 
     DataEngine *engine = PluginLoader::pluginLoader()->loadDataEngine(name);
     if (!engine) {
+        // Try installing the engine. However, it's too late for this request.
+        ComponentInstaller::self()->installMissingComponent("dataengine", name);
+
         return d->nullEngine();
     }
 

private/componentinstaller.cpp

@@ -0,0 +1,103 @@
+/*
+ *   Copyright 2011 Kevin Kofler <kevin.kofler@chello.at>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Library General Public License as
+ *   published by the Free Software Foundation; either version 2, or
+ *   (at your option) any later version.
+ *
+ *   This program 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 Library General Public
+ *   License along with this program; if not, write to the
+ *   Free Software Foundation, Inc.,
+ *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#include "private/componentinstaller_p.h"
+
+#include <kglobal.h>
+
+#ifdef PLASMA_ENABLE_PACKAGEKIT_SUPPORT
+#include <QSet>
+#include <QDBusInterface>
+#include <QDBusPendingCall>
+#include <QWidget>
+#include <QLatin1String>
+#include <QStringList>
+#endif
+
+namespace Plasma
+{
+
+class ComponentInstallerPrivate
+{
+    public:
+#ifdef PLASMA_ENABLE_PACKAGEKIT_SUPPORT
+        QSet<QString> alreadyPrompted;
+#endif
+};
+
+class ComponentInstallerSingleton
+{
+    public:
+        ComponentInstaller self;
+};
+
+K_GLOBAL_STATIC(ComponentInstallerSingleton, privateComponentInstallerSelf)
+
+ComponentInstaller *ComponentInstaller::self()
+{
+    return &privateComponentInstallerSelf->self;
+}
+
+ComponentInstaller::ComponentInstaller()
+    : d(new ComponentInstallerPrivate)
+{
+}
+
+ComponentInstaller::~ComponentInstaller()
+{
+    delete d;
+}
+
+void ComponentInstaller::installMissingComponent(const QString &type,
+                                                 const QString &name,
+                                                 QWidget *parent, bool force)
+{
+#ifdef PLASMA_ENABLE_PACKAGEKIT_SUPPORT
+    QString searchString = type + '-' + name;
+
+    if (!force) {
+        if (d->alreadyPrompted.contains(searchString)) {
+            return;
+        }
+    }
+
+    d->alreadyPrompted.insert(searchString);
+
+    QDBusInterface packageKit(QLatin1String("org.freedesktop.PackageKit"),
+                              QLatin1String("/org/freedesktop/PackageKit"),
+                              QLatin1String("org.freedesktop.PackageKit.Modify"));
+    // We don't check packageKit.isValid() because the service is activated on
+    // demand, so it will show up as "not valid".
+    WId wid = 0;
+    if (parent) {
+        wid = parent->winId();
+    }
+    QStringList resources;
+    resources.append(searchString);
+    packageKit.asyncCall(QLatin1String("InstallResources"), (unsigned int) wid,
+                         QLatin1String("plasma-service"), resources, QString());
+#else
+    Q_UNUSED(type);
+    Q_UNUSED(name);
+    Q_UNUSED(parent);
+    Q_UNUSED(force);
+#endif
+}
+
+} // namespace Plasma

private/componentinstaller_p.h

@@ -0,0 +1,94 @@
+/*
+ *   Copyright 2011 Kevin Kofler <kevin.kofler@chello.at>
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Library General Public License as
+ *   published by the Free Software Foundation; either version 2, or
+ *   (at your option) any later version.
+ *
+ *   This program 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 Library General Public
+ *   License along with this program; if not, write to the
+ *   Free Software Foundation, Inc.,
+ *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+
+#ifndef PLASMA_COMPONENTINSTALLER_H
+#define PLASMA_COMPONENTINSTALLER_H
+
+class QString;
+class QWidget;
+
+namespace Plasma
+{
+
+class ComponentInstallerPrivate;
+
+/**
+ * @class ComponentInstaller plasma/private/componentinstaller_p.h
+ *
+ * @short This class provides a generic API for installation of components.
+ *
+ * @internal
+ *
+ * Plasma::ComponentInstaller allows searching for a missing data or script
+ * engine by name, and allowing the user to install the missing service.
+ * Currently, PackageKit is supported as the mechanism to install components,
+ * but more mechanisms could be supported in the future through the same API.
+ *
+ * @since 4.8
+ */
+class ComponentInstaller
+{
+    public:
+        /**
+         * Singleton pattern accessor.
+         */
+        static ComponentInstaller *self();
+
+        /**
+         * Installs a missing component asynchronously.
+         *
+         * By default, this method will cache requested components and not
+         * prompt again for the same engine in the same session. The force
+         * parameter can be used to disable this mechanism, e.g. when the user
+         * just installed a new widget written in a scripting language, and so
+         * is likely to want the script engine installed after all.
+         *
+         * In the case of on-demand installation, this will unfortunately not
+         * allow the call which triggered the missing component lookup to
+         * succeed, but we cannot afford to block all of Plasma until the
+         * mechanism is done installing the service.
+         *
+         * This function does nothing if PackageKit integration was disabled at
+         * compile time.
+         *
+         * @param type the type of the component, should be "scriptengine" or
+         *             "dataengine"
+         * @param name the name of the component
+         * @param parent a parent widget, used to set the wid for PackageKit
+         * @param force whether to always prompt, even if recently prompted
+         */
+        void installMissingComponent(const QString &type, const QString &name,
+                                     QWidget *parent = 0, bool force = false);
+
+    private:
+        /**
+         * Default constructor. The singleton method self() is the
+         * preferred access mechanism.
+         */
+        ComponentInstaller();
+        ~ComponentInstaller();
+
+        ComponentInstallerPrivate *const d;
+
+        friend class ComponentInstallerSingleton;
+};
+
+} // namespace Plasma
+
+#endif // multiple inclusion guard

scripting/scriptengine.cpp

@@ -27,6 +27,7 @@
 #include "applet.h"
 #include "dataengine.h"
 #include "package.h"
+#include "private/componentinstaller_p.h"
 #include "scripting/appletscript.h"
 #include "scripting/dataenginescript.h"
 #include "scripting/runnerscript.h"
@@ -196,6 +197,9 @@ ScriptEngine *loadEngine(const QString &language, ComponentType type, QObject *p
                  << "! error reported: " << error;
     }
 
+    // Try installing the engine. However, it's too late for this request.
+    ComponentInstaller::self()->installMissingComponent("scriptengine", language);
+
     return 0;
 }