PySide6: Move the mutex for locking QObject allocation helpers to libpyside

Qml and Quick were using 2 different mutexes, which does not make
sense.

Task-number: PYSIDE-1709
Change-Id: Id0ec0f780c1d24e40a7f072dea62964ecf92e9d2
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

5 files changed, 16 insertions, 11 deletions

diff --git a/sources/pyside6/PySide6/QtQuick/pysidequickregistertype.cpp b/sources/pyside6/PySide6/QtQuick/pysidequickregistertype.cpp
index 3ccbe69a4..edca30620 100644
--- a/sources/pyside6/PySide6/QtQuick/pysidequickregistertype.cpp
+++ b/sources/pyside6/PySide6/QtQuick/pysidequickregistertype.cpp
@@ -51,18 +51,15 @@
 
 #include <QtCore/QMutex>
 
-// Mutex used to avoid race condition on PySide::nextQObjectMemoryAddr.
-static QMutex nextQmlElementMutex;
-
 static void createQuickItem(void *memory, void *type)
 {
-    QMutexLocker locker(&nextQmlElementMutex);
+    QMutexLocker locker(&PySide::nextQObjectMemoryAddrMutex());
     PySide::setNextQObjectMemoryAddr(memory);
     Shiboken::GilState state;
     PyObject *obj = PyObject_CallObject(reinterpret_cast<PyObject *>(type), 0);
     if (!obj || PyErr_Occurred())
         PyErr_Print();
-    PySide::setNextQObjectMemoryAddr(0);
+    PySide::setNextQObjectMemoryAddr(nullptr);
 }
 
 bool pyTypeObjectInheritsFromClass(PyTypeObject *pyObjType, QByteArray className)
diff --git a/sources/pyside6/libpyside/pyside.cpp b/sources/pyside6/libpyside/pyside.cpp
index 05c0e7486..b2bf0ed69 100644
--- a/sources/pyside6/libpyside/pyside.cpp
+++ b/sources/pyside6/libpyside/pyside.cpp
@@ -71,6 +71,7 @@
 #include <QtCore/QCoreApplication>
 #include <QtCore/QDir>
 #include <QtCore/QFileInfo>
+#include <QtCore/QMutex>
 #include <QtCore/QSharedPointer>
 #include <QtCore/QStack>
 #include <QtCore/QThread>
@@ -387,6 +388,12 @@ bool inherits(PyTypeObject *objType, const char *class_name)
     return inherits(base, class_name);
 }
 
+QMutex &nextQObjectMemoryAddrMutex()
+{
+    static QMutex mutex;
+    return mutex;
+}
+
 void *nextQObjectMemoryAddr()
 {
     return qobjectNextAddr;
diff --git a/sources/pyside6/libpyside/pysideqobject.h b/sources/pyside6/libpyside/pysideqobject.h
index 19e603bb7..538f6f024 100644
--- a/sources/pyside6/libpyside/pysideqobject.h
+++ b/sources/pyside6/libpyside/pysideqobject.h
@@ -48,6 +48,7 @@
 
 QT_FORWARD_DECLARE_CLASS(QObject)
 QT_FORWARD_DECLARE_STRUCT(QMetaObject)
+QT_FORWARD_DECLARE_CLASS(QMutex)
 
 namespace PySide
 {
@@ -83,7 +84,10 @@ PYSIDE_API QObject *convertToQObject(PyObject *object, bool raiseError);
 /// attribute related with name
 PYSIDE_API PyObject *getMetaDataFromQObject(QObject *cppSelf, PyObject *self, PyObject *name);
 
+/// Mutex for accessing QObject memory helpers from multiple threads
+PYSIDE_API QMutex &nextQObjectMemoryAddrMutex();
 PYSIDE_API void *nextQObjectMemoryAddr();
+/// Set the address where to allocate the next QObject (for QML)
 PYSIDE_API void setNextQObjectMemoryAddr(void *addr);
 
 PYSIDE_API PyObject *getWrapperForQObject(QObject *cppSelf, PyTypeObject *sbk_type);
diff --git a/sources/pyside6/libpysideqml/pysideqmlregistertype.cpp b/sources/pyside6/libpysideqml/pysideqmlregistertype.cpp
index cbacd5887..5f5d5fff8 100644
--- a/sources/pyside6/libpysideqml/pysideqmlregistertype.cpp
+++ b/sources/pyside6/libpysideqml/pysideqmlregistertype.cpp
@@ -59,20 +59,17 @@
 #include <QtQml/QJSValue>
 #include <QtQml/QQmlListProperty>
 
-// Mutex used to avoid race condition on PySide::nextQObjectMemoryAddr.
-static QMutex nextQmlElementMutex;
-
 static PySide::Qml::QuickRegisterItemFunction quickRegisterItemFunction = nullptr;
 
 static void createInto(void *memory, void *type)
 {
-    QMutexLocker locker(&nextQmlElementMutex);
+    QMutexLocker locker(&PySide::nextQObjectMemoryAddrMutex());
     PySide::setNextQObjectMemoryAddr(memory);
     Shiboken::GilState state;
     PyObject *obj = PyObject_CallObject(reinterpret_cast<PyObject *>(type), 0);
     if (!obj || PyErr_Occurred())
         PyErr_Print();
-    PySide::setNextQObjectMemoryAddr(0);
+    PySide::setNextQObjectMemoryAddr(nullptr);
 }
 
 PyTypeObject *qObjectType()
diff --git a/sources/shiboken6/generator/shiboken/cppgenerator.cpp b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
index e508b5855..f93024d55 100644
--- a/sources/shiboken6/generator/shiboken/cppgenerator.cpp
+++ b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
@@ -3679,7 +3679,7 @@ void CppGenerator::writeMethodCall(TextStream &s, const AbstractMetaFunctionCPtr
                             Indentation indent(uva);
 
                             uva << "cptr = new (addr) ::" << ctorCall << ";\n"
-                                << "PySide::setNextQObjectMemoryAddr(0);"
+                                << "PySide::setNextQObjectMemoryAddr(nullptr);"
                                 << '\n';
                         }
                         uva << "} else {\n";