From d29954ae3359c4ac5d6e59cef8249427568bc00a Mon Sep 17 00:00:00 2001
From: Vlad Zahorodnii <vlad.zahorodnii@kde.org>
Date: Mon, 19 Jul 2021 12:12:06 +0300
Subject: [PATCH] scripting: Make QTimer constructible

If a QObject is exposed to js using QJSEngine::newQMetaObject(), a new
instance of it can be made only with constructors exposed by Q_INVOKABLE

At the moment, QTimer's constructor is not Q_INVOKABLE, so code such as
`const timer = new QTimer()` will not work.

BUG: 439630
FIXED-IN: 5.22.4
---
 src/scripting/scripting.cpp |  7 ++++++-
 src/scripting/scripting.h   | 13 +++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/scripting/scripting.cpp b/src/scripting/scripting.cpp
index 6870121c9c..a53ee14616 100644
--- a/src/scripting/scripting.cpp
+++ b/src/scripting/scripting.cpp
@@ -92,6 +92,11 @@ void KWin::AbstractScript::stop()
     deleteLater();
 }
 
+KWin::ScriptTimer::ScriptTimer(QObject *parent)
+    : QTimer(parent)
+{
+}
+
 KWin::Script::Script(int id, QString scriptName, QString pluginName, QObject* parent)
     : AbstractScript(id, scriptName, pluginName, parent)
     , m_engine(new QJSEngine(this))
@@ -167,7 +172,7 @@ void KWin::Script::slotScriptLoadedFromFile()
     m_engine->installExtensions(QJSEngine::ConsoleExtension);
 
     // Make the timer visible to QJSEngine.
-    QJSValue timerMetaObject = m_engine->newQMetaObject(&QTimer::staticMetaObject);
+    QJSValue timerMetaObject = m_engine->newQMetaObject(&ScriptTimer::staticMetaObject);
     m_engine->globalObject().setProperty("QTimer", timerMetaObject);
 
     // Expose enums.
diff --git a/src/scripting/scripting.h b/src/scripting/scripting.h
index 85ce7b360d..8814dec94c 100644
--- a/src/scripting/scripting.h
+++ b/src/scripting/scripting.h
@@ -18,6 +18,7 @@
 #include <QStringList>
 #include <QJSEngine>
 #include <QJSValue>
+#include <QTimer>
 
 #include <QDBusContext>
 #include <QDBusMessage>
@@ -83,6 +84,18 @@ private:
     bool m_running;
 };
 
+/**
+ * In order to be able to construct QTimer objects in javascript, the constructor
+ * must be declared with Q_INVOKABLE.
+ */
+class ScriptTimer : public QTimer
+{
+    Q_OBJECT
+
+public:
+    Q_INVOKABLE ScriptTimer(QObject *parent = nullptr);
+};
+
 class Script : public AbstractScript, QDBusContext
 {
     Q_OBJECT