Port away from KToolInvocation

The problem with KToolInvocation is that it creates a dead lock on
Wayland in case kdeinit is not already running. It starts kdeinit
and does a QProcess::waitForFinished and our kdeinit needs to interact
with the wayland server. So dead lock.

As KRun also calls into the dangerous code path it's no option which
leaves us with QProcess to start the processes.

A nice side-effect is that we no don't need to link KF5::Service any
more from kwin_core. Now once Plasma and Notification don't use it
any more, it will be gone completely.

CMakeLists.txt

@@ -72,7 +72,6 @@ find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
     I18n
     Init
     Notifications
-    Service
     Package
     Plasma
     WidgetsAddons
@@ -86,6 +85,7 @@ find_package(KF5 ${KF5_MIN_VERSION} REQUIRED COMPONENTS
     KCMUtils
     KIO
     NewStuff
+    Service
     XmlGui
 )
 
@@ -502,7 +502,6 @@ set(kwin_KDE_LIBS
     KF5::GlobalAccelPrivate
     KF5::I18n
     KF5::Notifications
-    KF5::Service
     KF5::Package
     KF5::Plasma
     KF5::WindowSystem

config-kwin.h.cmake

@@ -7,6 +7,7 @@
 #define KWIN_VERSION_STRING "${PROJECT_VERSION}"
 #define XCB_VERSION_STRING "${XCB_VERSION}"
 #define KWIN_KILLER_BIN "${CMAKE_INSTALL_PREFIX}/${LIBEXEC_INSTALL_DIR}/kwin_killer_helper"
+#define KWIN_RULES_DIALOG_BIN "${CMAKE_INSTALL_PREFIX}/${LIBEXEC_INSTALL_DIR}/kwin_rules_dialog"
 #cmakedefine01 HAVE_WAYLAND
 #cmakedefine01 HAVE_WAYLAND_EGL
 #cmakedefine01 HAVE_WAYLAND_CURSOR

main.cpp

@@ -533,6 +533,11 @@ bool Application::usesLibinput()
     return s_useLibinput;
 }
 
+QProcessEnvironment Application::processStartupEnvironment() const
+{
+    return QProcessEnvironment::systemEnvironment();
+}
+
 } // namespace
 
 #include "main.moc"

main.h

@@ -30,6 +30,7 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 // Qt
 #include <QApplication>
 #include <QAbstractNativeEventFilter>
+#include <QProcessEnvironment>
 
 class QCommandLineParser;
 
@@ -141,6 +142,8 @@ public:
         return m_connection;
     }
 
+    virtual QProcessEnvironment processStartupEnvironment() const;
+
     static void setupMalloc();
     static void setupLocalizedString();
     static void setupLoggingCategoryFilters();

main_wayland.cpp

@@ -189,15 +189,14 @@ void ApplicationWayland::continueStartupWithX()
         }
     }
 
+    m_environment.insert(QStringLiteral("DISPLAY"), QString::fromUtf8(qgetenv("DISPLAY")));
     // start the applications passed to us as command line arguments
     if (!m_applicationsToStart.isEmpty()) {
-        QProcessEnvironment environment = m_environment;
-        environment.insert(QStringLiteral("DISPLAY"), QString::fromUtf8(qgetenv("DISPLAY")));
         for (const QString &application: m_applicationsToStart) {
             // note: this will kill the started process when we exit
             // this is going to happen anyway as we are the wayland and X server the app connects to
             QProcess *p = new QProcess(this);
-            p->setProcessEnvironment(environment);
+            p->setProcessEnvironment(m_environment);
             p->start(application);
         }
     }

main_wayland.h

@@ -50,6 +50,10 @@ public:
 
     bool notify(QObject *o, QEvent *e) override;
 
+    QProcessEnvironment processStartupEnvironment() const override {
+        return m_environment;
+    }
+
 protected:
     void performStartup() override;
 

rules.cpp

@@ -27,7 +27,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include <QTemporaryFile>
 #include <QFile>
 #include <QFileInfo>
-#include <ktoolinvocation.h>
 #include <QDebug>
 
 #ifndef KCMRULES
@@ -995,7 +994,19 @@ void RuleBook::edit(AbstractClient* c, bool whole_app)
     args << QStringLiteral("--wid") << QString::number(c->window());
     if (whole_app)
         args << QStringLiteral("--whole-app");
-    KToolInvocation::kdeinitExec(QStringLiteral("kwin_rules_dialog"), args);
+    QProcess *p = new QProcess(this);
+    p->setArguments(args);
+    p->setProcessEnvironment(kwinApp()->processStartupEnvironment());
+    p->setProgram(QStringLiteral(KWIN_RULES_DIALOG_BIN));
+    connect(p, static_cast<void (QProcess::*)(int, QProcess::ExitStatus)>(&QProcess::finished), this, &QProcess::deleteLater);
+    connect(p, static_cast<void (QProcess::*)(QProcess::ProcessError)>(&QProcess::error), this,
+        [p] (QProcess::ProcessError e) {
+            if (e == QProcess::FailedToStart) {
+                qCDebug(KWIN_CORE) << "Failed to start kwin_rules_dialog";
+            }
+        }
+    );
+    p->start();
 }
 
 void RuleBook::load()

useractions.cpp

@@ -47,7 +47,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #endif
 
 #include <KProcess>
-#include <KToolInvocation>
 
 #include <QAction>
 #include <QCheckBox>
@@ -307,14 +306,23 @@ void UserActionsMenu::init()
                                         "Window &Manager Settings..."));
         action->setIcon(QIcon::fromTheme(QStringLiteral("configure")));
         connect(action, &QAction::triggered, this,
-            []() {
+            [this]() {
                 // opens the KWin configuration
                 QStringList args;
                 args << QStringLiteral("--icon") << QStringLiteral("preferences-system-windows") << configModules(false);
-                QString error;
-                if (KToolInvocation::kdeinitExec(QStringLiteral("kcmshell5"), args, &error) != 0) {
-                    qCDebug(KWIN_CORE) << "Failed to start kcmshell5: " << error;
-                }
+                QProcess *p = new QProcess(this);
+                p->setArguments(args);
+                p->setProcessEnvironment(kwinApp()->processStartupEnvironment());
+                p->setProgram(QStringLiteral("kcmshell5"));
+                connect(p, static_cast<void (QProcess::*)(int, QProcess::ExitStatus)>(&QProcess::finished), this, &QProcess::deleteLater);
+                connect(p, static_cast<void (QProcess::*)(QProcess::ProcessError)>(&QProcess::error), this,
+                    [p] (QProcess::ProcessError e) {
+                        if (e == QProcess::FailedToStart) {
+                            qCDebug(KWIN_CORE) << "Failed to start kcmshell5";
+                        }
+                    }
+                );
+                p->start();
             }
         );
     }