From 007a31709950f2251fef083f27b12829e6554f20 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <mgraesslin@kde.org>
Date: Fri, 2 Oct 2015 09:47:27 +0200
Subject: [PATCH] [wayland] Add options depending on available backend plugins

As distributions do not ship all plugins let's try to filter the options
based on the plugins which are actually available. There is no point in
allowing e.g. framebuffer just to notice then that the plugin is not
shipped ending in confusing error for the user. So let's only add the
options which actually make sense.
---
 main_wayland.cpp | 39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/main_wayland.cpp b/main_wayland.cpp
index 36cc34864b..949a1a26e5 100644
--- a/main_wayland.cpp
+++ b/main_wayland.cpp
@@ -384,6 +384,13 @@ int main(int argc, char * argv[])
     KWin::Application::createAboutData();
 
     const auto availablePlugins = KPluginLoader::findPlugins(QStringLiteral("org.kde.kwin.waylandbackends"));
+    auto hasPlugin = [&availablePlugins] (const QString &name) {
+        return std::any_of(availablePlugins.begin(), availablePlugins.end(),
+            [name] (const KPluginMetaData &plugin) {
+                return plugin.pluginId() == name;
+            }
+        );
+    };
 
     QCommandLineOption xwaylandOption(QStringLiteral("xwayland"),
                                       i18n("Start a rootless Xwayland server."));
@@ -417,16 +424,28 @@ int main(int argc, char * argv[])
     a.setupCommandLine(&parser);
     parser.addOption(xwaylandOption);
     parser.addOption(waylandSocketOption);
-    parser.addOption(windowedOption);
-    parser.addOption(x11DisplayOption);
-    parser.addOption(waylandDisplayOption);
-    parser.addOption(framebufferOption);
-    parser.addOption(framebufferDeviceOption);
-    parser.addOption(widthOption);
-    parser.addOption(heightOption);
+    if (hasPlugin(KWin::s_x11Plugin) || hasPlugin(KWin::s_waylandPlugin)) {
+        parser.addOption(windowedOption);
+    }
+    if (hasPlugin(KWin::s_x11Plugin)) {
+        parser.addOption(x11DisplayOption);
+    }
+    if (hasPlugin(KWin::s_waylandPlugin)) {
+        parser.addOption(waylandDisplayOption);
+    }
+    if (hasPlugin(KWin::s_fbdevPlugin)) {
+        parser.addOption(framebufferOption);
+        parser.addOption(framebufferDeviceOption);
+    }
+    if (hasPlugin(KWin::s_x11Plugin)) {
+        parser.addOption(widthOption);
+        parser.addOption(heightOption);
+    }
 #if HAVE_LIBHYBRIS
     QCommandLineOption hwcomposerOption(QStringLiteral("hwcomposer"), i18n("Use libhybris hwcomposer"));
-    parser.addOption(hwcomposerOption);
+    if (hasPlugin(KWin::s_hwcomposerPlugin)) {
+        parser.addOption(hwcomposerOption);
+    }
 #endif
 #if HAVE_INPUT
     QCommandLineOption libinputOption(QStringLiteral("libinput"),
@@ -435,7 +454,9 @@ int main(int argc, char * argv[])
 #endif
 #if HAVE_DRM
     QCommandLineOption drmOption(QStringLiteral("drm"), i18n("Render through drm node."));
-    parser.addOption(drmOption);
+    if (hasPlugin(KWin::s_drmPlugin)) {
+        parser.addOption(drmOption);
+    }
 #endif
 
     QCommandLineOption inputMethodOption(QStringLiteral("inputmethod"),