Q_{APPLICATION,GLOBAL}_STATIC: use variadic macros

We can't remove Q_GLOBAL_STATIC_WITH_ARGS, for compatibility reasons.
It's also the only way to pass uniform initialization (i.e., initialize
the value as value{with_braces}), though I don't think this is used
almost anywhere due to the fact that you couldn't pass more than one
argument. But Q_APPLICATION_STATIC is new in 6.3, so we have time to
change it.

[ChangeLog][QtCore][QGlobalStatic] The Q_GLOBAL_STATIC macro is now
variadic. Any extra arguments are used as constructor arguments,
obliterating the need to use Q_GLOBAL_STATIC_WITH_ARGS().

Pick-to: 6.3
Change-Id: Ib42b3adc93bf4d43bd55fffd16be3656a512fe53
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

5 files changed, 37 insertions, 56 deletions

diff --git a/src/corelib/global/qglobalstatic.h b/src/corelib/global/qglobalstatic.h
index cf96e5ae8e..098aee966b 100644
--- a/src/corelib/global/qglobalstatic.h
+++ b/src/corelib/global/qglobalstatic.h
@@ -145,8 +145,8 @@ protected:
     static QGlobalStatic<QtGlobalStatic::Holder<Q_QGS_ ## NAME>> NAME;      \
     /**/
 
-#define Q_GLOBAL_STATIC(TYPE, NAME)                                         \
-    Q_GLOBAL_STATIC_WITH_ARGS(TYPE, NAME, ())
+#define Q_GLOBAL_STATIC(TYPE, NAME, ...)                                    \
+    Q_GLOBAL_STATIC_WITH_ARGS(TYPE, NAME, (__VA_ARGS__))
 
 QT_END_NAMESPACE
 #endif // QGLOBALSTATIC_H
diff --git a/src/corelib/global/qglobalstatic.qdoc b/src/corelib/global/qglobalstatic.qdoc
index 99416ad102..1e3fc6f11c 100644
--- a/src/corelib/global/qglobalstatic.qdoc
+++ b/src/corelib/global/qglobalstatic.qdoc
@@ -26,7 +26,7 @@
 ****************************************************************************/
 
 /*!
-    \macro Q_GLOBAL_STATIC(Type, VariableName)
+    \macro Q_GLOBAL_STATIC(Type, VariableName, ...)
     \since 5.1
     \relates QGlobalStatic
 
@@ -36,6 +36,11 @@
     will not increase the application or the library's load time. Additionally,
     the object is initialized in a thread-safe manner on all platforms.
 
+    Since Qt 6.3, this macro admits variadic arguments, which are used to
+    initialize the object, thus making the need for \l
+    Q_GLOBAL_STATIC_WITH_ARGS unnecessary. Please note the arguments do not
+    require an extra set of parentheses, unlike the older macro.
+
     The typical use of this macro is as follows, in a global context (that is,
     outside of any function bodies):
 
@@ -273,12 +278,13 @@
 
     \endomit
 
-    \sa Q_GLOBAL_STATIC_WITH_ARGS(), QGlobalStatic
+    \sa Q_GLOBAL_STATIC_WITH_ARGS(), Q_APPLICATION_STATIC(), QGlobalStatic
 */
 
 /*!
     \macro Q_GLOBAL_STATIC_WITH_ARGS(Type, VariableName, Arguments)
     \since 5.1
+    \obsolete
     \relates QGlobalStatic
 
     Creates a global and static object of type \l QGlobalStatic, of name \a
@@ -296,7 +302,12 @@
     \endcode
 
     The \a Arguments macro parameter must always include the parentheses or, if
-    C++11 uniform initialization is allowed, the braces.
+    C++11 uniform initialization is allowed, the braces. The above call is
+    equivalent to
+
+    \code
+        Q_GLOBAL_STATIC(MyType, staticType, 42, "Hello", "World")
+    \endcode
 
     Aside from the actual initialization of the contents with the supplied
     arguments, this macro behaves identically to Q_GLOBAL_STATIC(). Please
diff --git a/src/corelib/kernel/qapplicationstatic.h b/src/corelib/kernel/qapplicationstatic.h
index f34bd806a2..93a5062776 100644
--- a/src/corelib/kernel/qapplicationstatic.h
+++ b/src/corelib/kernel/qapplicationstatic.h
@@ -100,21 +100,18 @@ template <typename QAS> struct ApplicationHolder
 };
 } // namespace QtGlobalStatic
 
-#define Q_APPLICATION_STATIC_WITH_ARGS(TYPE, NAME, ARGS)                    \
+#define Q_APPLICATION_STATIC(TYPE, NAME, ...) \
     namespace { struct Q_QAS_ ## NAME {                                     \
         typedef TYPE QAS_Type;                                              \
         static void innerFunction(void *pointer)                            \
-            noexcept(noexcept(std::remove_cv_t<QAS_Type> ARGS))             \
+            noexcept(noexcept(std::remove_cv_t<QAS_Type>(__VA_ARGS__)))     \
         {                                                                   \
-            new (pointer) QAS_Type ARGS;                                    \
+            new (pointer) QAS_Type(__VA_ARGS__);                            \
         }                                                                   \
     }; }                                                                    \
     static QGlobalStatic<QtGlobalStatic::ApplicationHolder<Q_QAS_ ## NAME>> NAME;\
     /**/
 
-#define Q_APPLICATION_STATIC(TYPE, NAME) \
-    Q_APPLICATION_STATIC_WITH_ARGS(TYPE, NAME, ())
-
 QT_END_NAMESPACE
 
 #endif // QAPPLICATIONSTATIC_H
diff --git a/src/corelib/kernel/qapplicationstatic.qdoc b/src/corelib/kernel/qapplicationstatic.qdoc
index 5903cdc20b..76507a2824 100644
--- a/src/corelib/kernel/qapplicationstatic.qdoc
+++ b/src/corelib/kernel/qapplicationstatic.qdoc
@@ -26,17 +26,18 @@
 ****************************************************************************/
 
 /*!
-    \macro Q_APPLICATION_STATIC(Type, VariableName)
+    \macro Q_APPLICATION_STATIC(Type, VariableName, ...)
     \since 6.3
     \relates QGlobalStatic
 
     This macro extends Q_GLOBAL_STATIC and creates a global and static object
-    of type \l QGlobalStatic, of name \a VariableName and that behaves as a
-    pointer to \a Type, where the actual lifetime of the type is bound to the
-    QCoreApplication. The object created by Q_APPLICATION_STATIC initializes
-    itself on the first use, which means that it will not increase the application
-    or the library's load time. Additionally, the object is initialized in a
-    thread-safe manner on all platforms.
+    of type \l QGlobalStatic, of name \a VariableName, initialized by the
+    variadic arguments, and that behaves as a pointer to \a Type, where the
+    actual lifetime of the type is bound to the QCoreApplication. The object
+    created by Q_APPLICATION_STATIC initializes itself on the first use, which
+    means that it will not increase the application or the library's load time.
+    Additionally, the object is initialized in a thread-safe manner on all
+    platforms.
 
     In contrast to Q_GLOBAL_STATIC where the type is only meant to be destroyed at
     program exit, here the actual lifetime of the type is bound to the lifetime of
@@ -56,9 +57,14 @@
     outside of any function bodies):
 
     \code
-        Q_APPLICATION_STATIC(MyQObjectType, staticType)
+        Q_APPLICATION_STATIC(MyQObjectType, staticType, "some string", function())
     \endcode
 
+    Do note that the arguments passed in variadic fashion to this macro are
+    evaluated every time the object is constructed, so in the above example,
+    the function \c{function} will be called more than once if the object is
+    recreated.
+
     Aside from the value also being bound to the lifetime of the QCoreApplication,
     this macro behaves identically to Q_GLOBAL_STATIC(). Please see that macro's
     documentation for more information.
@@ -99,38 +105,5 @@
 
     \endomit
 
-    \sa Q_APPLICATION_STATIC_WITH_ARGS(), QGlobalStatic
-*/
-
-/*!
-    \macro Q_APPLICATION_STATIC_WITH_ARGS(Type, VariableName, Arguments)
-    \since 6.3
-    \relates QGlobalStatic
-
-    Creates a global and static object of type \l QGlobalStatic, of name \a
-    VariableName, initialized by the arguments \a Arguments and that behaves as
-    a pointer to \a Type, where the actual lifetime of the type is bound to the
-    QCoreApplication. The object created by Q_APPLICATION_STATIC_WITH_ARGS
-    initializes itself on the first use, which means that it will not increase
-    the application or the library's load time. Additionally, the object is
-    initialized in a thread-safe manner on all platforms.
-
-    Since the value is bound to the QCoreApplication it should only ever be accessed,
-    if there is a valid QCoreApplication::instance().
-
-    The typical use of this macro is as follows, in a global context (that is,
-    outside of any function bodies):
-
-    \code
-        Q_APPLICATION_STATIC_WITH_ARGS(MyQObjectType, staticType, (42, "Hello", "World"))
-    \endcode
-
-    The \a Arguments macro parameter must always include the parentheses or, if
-    C++11 uniform initialization is allowed, the braces.
-
-    Aside from the actual initialization of the contents with the supplied
-    arguments, this macro behaves identically to Q_APPLICATION_STATIC(). Please
-    see that macro's documentation for more information.
-
-    \sa Q_APPLICATION_STATIC(), QGlobalStatic
+    \sa Q_GLOBAL_STATIC, QGlobalStatic
 */
diff --git a/src/network/access/qnetworkaccessmanager.cpp b/src/network/access/qnetworkaccessmanager.cpp
index 230aa40af6..b04f0cba7a 100644
--- a/src/network/access/qnetworkaccessmanager.cpp
+++ b/src/network/access/qnetworkaccessmanager.cpp
@@ -106,9 +106,9 @@ Q_APPLICATION_STATIC(QNetworkAccessFileBackendFactory, fileBackend)
 Q_GLOBAL_STATIC(QNetworkAccessDebugPipeBackendFactory, debugpipeBackend)
 #endif
 
-Q_APPLICATION_STATIC_WITH_ARGS(QFactoryLoader, loader,
-                          (QNetworkAccessBackendFactory_iid,
-                           QLatin1String("/networkaccess")))
+Q_APPLICATION_STATIC(QFactoryLoader, loader, QNetworkAccessBackendFactory_iid,
+                     QLatin1String("/networkaccess"))
+
 #if defined(Q_OS_MACOS)
 bool getProxyAuth(const QString& proxyHostname, const QString &scheme, QString& username, QString& password)
 {