Add GrantleeTheme::Engine to avoid code duplication

GrantleeTheme::Engine is a simple subclass of Grantlee::Engine which
sets up the correct plugin path and loads the default KDE plugins.

It also provides easy access to Ki18n localizer.

src/CMakeLists.txt

@@ -7,6 +7,7 @@ add_subdirectory(plugin)
 set(libgrantleetheme_SRCS
     grantleetheme.cpp
     grantleethememanager.cpp
+    grantleethemeengine.cpp
     grantleeki18nlocalizer.cpp
     qtresourcetemplateloader.cpp
 )
@@ -46,6 +47,7 @@ ecm_generate_headers(GrantleeTheme_CamelCase_HEADERS
   HEADER_NAMES
   GrantleeThemeManager
   GrantleeTheme
+  GrantleeThemeEngine
   QtResourceTemplateLoader
   GrantleeKi18nLocalizer
   REQUIRED_HEADERS GrantleeTheme_HEADERS

src/grantleetheme.cpp

@@ -18,6 +18,7 @@
 #include "grantleetheme.h"
 #include "grantleetheme_p.h"
 #include "grantleetheme_debug.h"
+#include "grantleethemeengine.h"
 #include "config-grantleetheme.h"
 
 #include <KConfig>
@@ -57,11 +58,7 @@ ThemePrivate::~ThemePrivate()
 
 void ThemePrivate::setupEngine()
 {
-    sEngine = new Grantlee::Engine;
-    sEngine->addPluginPath(QStringLiteral(GRANTLEE_PLUGIN_INSTALL_DIR));
-    sEngine->addDefaultLibrary(QStringLiteral("grantlee_i18ntags"));
-    sEngine->addDefaultLibrary(QStringLiteral("kde_grantlee_plugin"));
-    sEngine->setSmartTrimEnabled(true);
+    sEngine = new GrantleeTheme::Engine();
 }
 
 void ThemePrivate::setupLoader()

src/grantleethemeengine.cpp

+/*
+  Copyright (c) 2016 Daniel Vrátil <dvratil@kde.org>
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License, version 2, as
+  published by the Free Software Foundation.
+
+  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 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 "grantleethemeengine.h"
+#include "grantleeki18nlocalizer.h"
+
+#include "config-grantleetheme.h"
+
+using namespace GrantleeTheme;
+
+class GrantleeTheme::Engine::Private
+{
+public:
+    Private()
+    {
+    }
+
+    ~Private()
+    {
+    }
+
+    QWeakPointer<GrantleeKi18nLocalizer> localizer;
+};
+
+
+Engine::Engine(QObject *parent)
+    : Grantlee::Engine(parent)
+    , d(new Private)
+{
+    addPluginPath(QStringLiteral(GRANTLEE_PLUGIN_INSTALL_DIR));
+    addDefaultLibrary(QStringLiteral("grantlee_i18ntags"));
+    addDefaultLibrary(QStringLiteral("kde_grantlee_plugin"));
+    addDefaultLibrary(QStringLiteral("grantlee_scriptabletags"));
+    setSmartTrimEnabled(true);
+}
+
+Engine::~Engine()
+{
+    delete d;
+}
+
+QSharedPointer<GrantleeKi18nLocalizer> Engine::localizer() const
+{
+    auto loc = d->localizer.toStrongRef();
+    if (!loc) {
+        loc.reset(new GrantleeKi18nLocalizer());
+        d->localizer = loc.toWeakRef();
+    }
+    return loc;
+}

src/grantleethemeengine.h

+/*
+  Copyright (c) 2016 Daniel Vrátil <dvratil@kde.org>
+
+  This program is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License, version 2, as
+  published by the Free Software Foundation.
+
+  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 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 GRANTLEETHEMEENGINE_H
+#define GRANTLEETHEMEENGINE_H
+
+#include <grantlee/engine.h>
+#include <QSharedPointer>
+
+#include "grantleetheme_export.h"
+
+namespace GrantleeTheme {
+
+class GrantleeKi18nLocalizer;
+
+class GRANTLEETHEME_EXPORT Engine : public Grantlee::Engine
+{
+    Q_OBJECT
+
+public:
+    Engine(QObject *parent = Q_NULLPTR);
+    ~Engine() Q_DECL_OVERRIDE;
+
+    QSharedPointer<GrantleeKi18nLocalizer> localizer() const;
+
+private:
+    class Private;
+    Private *const d;
+};
+
+}
+
+#endif