shiboken6: Implement opaque containers for getters returning a const reference

Add a bool m_const member to the container helper template that
indicates a const container. Error out of the modification functions
if that is set.  Create an additional creation function for the const
case. A const opaque containers is then of same Python type as the
non-const version, requiring no further type checks.

Pick-to: 6.2
Task-number: PYSIDE-1605
Change-Id: I45faeb0d68e6144a9dfbe25497694b8acdd98c09
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

1 files changed, 6 insertions, 3 deletions

diff --git a/sources/shiboken6/generator/shiboken/cppgenerator.cpp b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
index a6abeb077..06299a2ab 100644
--- a/sources/shiboken6/generator/shiboken/cppgenerator.cpp
+++ b/sources/shiboken6/generator/shiboken/cppgenerator.cpp
@@ -197,8 +197,11 @@ static QString opaqueContainerCreationFunc(const AbstractMetaType &type)
         static_cast<const ContainerTypeEntry *>(type.typeEntry());
     const auto *instantiationTypeEntry =
         type.instantiations().constFirst().typeEntry();
-    return u"create"_qs
-           + containerTypeEntry->opaqueContainerName(instantiationTypeEntry->name());
+    QString result = u"create"_qs;
+    if (type.isConstant())
+        result += u"Const"_qs;
+    result += containerTypeEntry->opaqueContainerName(instantiationTypeEntry->name());
+    return result;
 }
 
 // Write declaration of the function to create PyObject wrapping a container
@@ -206,7 +209,7 @@ static void writeOpaqueContainerCreationFuncDecl(TextStream &s, const QString &n
                                                  AbstractMetaType type)
 {
     type.setReferenceType(NoReference);
-    type.setConstant(false);
+    // Maintain const
     s << "PyObject *" << name << '(' << type.cppSignature() << "*);\n";
 }