QObject: Add connect() overload with context arg

On C++, there is an overload of QObject::connect() that allows passing a
context object. This creates a connection in the context object's event
loop instead of that of the caller. This implements said overload in
Python.

Change-Id: Ia6a098a04470741efd450818c31aa5bffb1bd9f8
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>
(cherry picked from commit acab25a3ccb836818e5089b23d40196bc7414b7a)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

7 files changed, 137 insertions, 0 deletions

diff --git a/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml b/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml
index bccd5f02d..5168373fd 100644
--- a/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml
+++ b/sources/pyside6/PySide6/QtCore/typesystem_core_common.xml
@@ -1748,6 +1748,10 @@
                   return-type="QMetaObject::Connection" static="yes">
         <inject-code class="target" position="beginning" file="../glue/qtcore.cpp" snippet="qobject-connect-4"/>
     </add-function>
+    <add-function signature="connect(const QObject*@sender@,const char*@signal@,const QObject*@context@,PyCallable*@functor@,Qt::ConnectionType@type@=Qt::AutoConnection)"
+                  return-type="QMetaObject::Connection" static="yes">
+        <inject-code class="target" position="beginning" file="../glue/qtcore.cpp" snippet="qobject-connect-4-context"/>
+    </add-function>
     <!-- static version -->
     <add-function signature="connect(const char*@signal@,PyCallable*@functor@,Qt::ConnectionType@type@=Qt::AutoConnection)"
                   return-type="QMetaObject::Connection">
diff --git a/sources/pyside6/PySide6/glue/qtcore.cpp b/sources/pyside6/PySide6/glue/qtcore.cpp
index a687d8447..ed1cb100f 100644
--- a/sources/pyside6/PySide6/glue/qtcore.cpp
+++ b/sources/pyside6/PySide6/glue/qtcore.cpp
@@ -321,6 +321,12 @@ PyModule_AddStringConstant(module, "__version__", qVersion());
 %PYARG_0 = %CONVERTTOPYTHON[%RETURN_TYPE](%0);
 // @snippet qobject-connect-4
 
+// @snippet qobject-connect-4-context
+// %FUNCTION_NAME() - disable generation of function call.
+%RETURN_TYPE %0 = PySide::qobjectConnectCallback(%1, %2, %3, %PYARG_4, %5);
+%PYARG_0 = %CONVERTTOPYTHON[%RETURN_TYPE](%0);
+// @snippet qobject-connect-4-context
+
 // @snippet qobject-connect-5
 // %FUNCTION_NAME() - disable generation of function call.
 %RETURN_TYPE %0 = PySide::qobjectConnectCallback(%CPPSELF, %1, %PYARG_2, %3);
diff --git a/sources/pyside6/libpyside/CMakeLists.txt b/sources/pyside6/libpyside/CMakeLists.txt
index 01a0a66b0..e9fd0d56e 100644
--- a/sources/pyside6/libpyside/CMakeLists.txt
+++ b/sources/pyside6/libpyside/CMakeLists.txt
@@ -5,7 +5,10 @@ project(libpyside)
 
 set(libpyside_libraries Qt::Core Qt::CorePrivate)
 
+set(CMAKE_AUTOMOC ON)
+
 set(libpyside_HEADERS # installed below
+    pysideqslotobject_p.h
     class_property.h
     dynamicqmetaobject.h
     feature_select.h
@@ -41,6 +44,7 @@ set(libpyside_HEADERS # installed below
 )
 
 set(libpyside_SRC
+    pysideqslotobject_p.cpp
     class_property.cpp
     dynamicqmetaobject.cpp
     feature_select.cpp
diff --git a/sources/pyside6/libpyside/pysideqslotobject_p.cpp b/sources/pyside6/libpyside/pysideqslotobject_p.cpp
new file mode 100644
index 000000000..914be898a
--- /dev/null
+++ b/sources/pyside6/libpyside/pysideqslotobject_p.cpp
@@ -0,0 +1,36 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#include "pysideqslotobject_p.h"
+
+#include <autodecref.h>
+#include <gilstate.h>
+
+namespace PySide
+{
+
+void PySideQSlotObject::impl(int which, QSlotObjectBase *this_, QObject *receiver,
+                             void **args, bool *ret)
+{
+    auto self = static_cast<PySideQSlotObject *>(this_);
+    switch (which) {
+    case Destroy:
+        delete self;
+        break;
+    case Call:
+        {
+            Shiboken::GilState state;
+            Shiboken::AutoDecRef arglist(PyTuple_New(0));
+            Shiboken::AutoDecRef ret(PyObject_CallObject(self->callable, arglist));
+            break;
+        }
+    case Compare:
+    case NumOperations:
+        Q_UNUSED(receiver);
+        Q_UNUSED(args);
+        Q_UNUSED(ret);
+        break;
+    }
+}
+
+} // namespace PySide
diff --git a/sources/pyside6/libpyside/pysideqslotobject_p.h b/sources/pyside6/libpyside/pysideqslotobject_p.h
new file mode 100644
index 000000000..d7d258505
--- /dev/null
+++ b/sources/pyside6/libpyside/pysideqslotobject_p.h
@@ -0,0 +1,39 @@
+// Copyright (C) 2024 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
+
+#ifndef PYSIDEQSLOTOBJECT_P_H
+#define PYSIDEQSLOTOBJECT_P_H
+
+#include "pysidemacros.h"
+#include <sbkpython.h>
+
+#include <QtCore/QObject>
+#include <QtCore/qobjectdefs.h>
+
+namespace PySide
+{
+
+class PySideQSlotObject : public QtPrivate::QSlotObjectBase
+{
+    PyObject *callable;
+
+    static void impl(int which, QSlotObjectBase *this_, QObject *receiver, void **args, bool *ret);
+
+public:
+    PySideQSlotObject(PyObject *callable) : QtPrivate::QSlotObjectBase(&impl), callable(callable)
+    {
+        Py_INCREF(callable);
+    }
+
+    ~PySideQSlotObject()
+    {
+        auto gstate = PyGILState_Ensure();
+        Py_DECREF(callable);
+        PyGILState_Release(gstate);
+    }
+};
+
+
+} // namespace PySide
+
+#endif // PYSIDEQSLOTOBJECT_P_H
diff --git a/sources/pyside6/libpyside/qobjectconnect.cpp b/sources/pyside6/libpyside/qobjectconnect.cpp
index 15b71766c..c47c96eb8 100644
--- a/sources/pyside6/libpyside/qobjectconnect.cpp
+++ b/sources/pyside6/libpyside/qobjectconnect.cpp
@@ -3,6 +3,7 @@
 
 #include "qobjectconnect.h"
 #include "pysideqobject.h"
+#include "pysideqslotobject_p.h"
 #include "pysidesignal.h"
 #include "pysideutils.h"
 #include "signalmanager.h"
@@ -15,6 +16,8 @@
 #include <QtCore/QMetaMethod>
 #include <QtCore/QObject>
 
+#include <QtCore/private/qobject_p.h>
+
 #include <string_view>
 
 static bool isMethodDecorator(PyObject *method, bool is_pymethod, PyObject *self)
@@ -259,6 +262,46 @@ QMetaObject::Connection qobjectConnectCallback(QObject *source, const char *sign
     return connection;
 }
 
+QMetaObject::Connection qobjectConnectCallback(QObject *source, const char *signal, QObject *context,
+                                               PyObject *callback, Qt::ConnectionType type)
+{
+    if (!signal || !PySide::Signal::checkQtSignal(signal))
+        return {};
+
+    const int signalIndex =
+        PySide::SignalManager::registerMetaMethodGetIndex(source, signal + 1,
+                                                          QMetaMethod::Signal);
+    if (signalIndex == -1)
+        return {};
+
+    // Extract receiver from callback
+    const GetReceiverResult receiver = getReceiver(source, signal + 1, callback);
+    if (receiver.receiver == nullptr && receiver.self == nullptr)
+        return {};
+
+    PySide::SignalManager &signalManager = PySide::SignalManager::instance();
+
+    PySideQSlotObject *slotObject = new PySideQSlotObject(callback);
+
+    QMetaObject::Connection connection{};
+    Py_BEGIN_ALLOW_THREADS // PYSIDE-2367, prevent threading deadlocks with connectNotify()
+    connection = QObjectPrivate::connect(source, signalIndex, context, slotObject, type);
+    Py_END_ALLOW_THREADS
+    if (!connection) {
+        if (receiver.usingGlobalReceiver)
+            signalManager.releaseGlobalReceiver(source, receiver.receiver);
+        return {};
+    }
+
+    Q_ASSERT(receiver.receiver);
+    if (receiver.usingGlobalReceiver)
+        signalManager.notifyGlobalReceiver(receiver.receiver);
+
+    const QMetaMethod signalMethod = receiver.receiver->metaObject()->method(signalIndex);
+    static_cast<FriendlyQObject *>(source)->connectNotify(signalMethod);
+    return connection;
+}
+
 bool qobjectDisconnectCallback(QObject *source, const char *signal, PyObject *callback)
 {
     if (!PySide::Signal::checkQtSignal(signal))
diff --git a/sources/pyside6/libpyside/qobjectconnect.h b/sources/pyside6/libpyside/qobjectconnect.h
index 70b862233..c99b8006e 100644
--- a/sources/pyside6/libpyside/qobjectconnect.h
+++ b/sources/pyside6/libpyside/qobjectconnect.h
@@ -33,6 +33,11 @@ PYSIDE_API QMetaObject::Connection
     qobjectConnectCallback(QObject *source, const char *signal,
                            PyObject *callback, Qt::ConnectionType type);
 
+/// Helpers for QObject::connect(): Make a connection to a Python callback and a context object
+PYSIDE_API QMetaObject::Connection
+    qobjectConnectCallback(QObject *source, const char *signal, QObject *context,
+                           PyObject *callback, Qt::ConnectionType type);
+
 /// Helpers for QObject::disconnect(): Disconnect a Python callback
 PYSIDE_API bool qobjectDisconnectCallback(QObject *source, const char *signal,
                                           PyObject *callback);