From 2bf186a2e598a4bccdc4979085e8e4d963a3819d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jo=C3=A3o=20Abecasis?= <joao.abecasis@nokia.com>
Date: Wed, 25 Jan 2012 17:40:24 +0100
Subject: [PATCH] Allow function types to be registered without workarounds
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Commit 4b8ceb41aed352f10d36db5284453f425dbc5f3f added the requirement
that pointed-to types need to be registered when registering pointer
types. Unfortunately, the implementation also affects function pointer
types.

This change whitelists 0, 1, 2 and 3 argument functions as not deriving
from QObject, forgoing the need to workaround details of the type
registration implementation when registering those function pointer
types.

Change-Id: I4d855e9d70a8179a6e31b84623ad5bf063e0d6d8
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@nokia.com>
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>
---
 src/corelib/io/qtextstream.h                      |  6 ------
 src/corelib/kernel/qmetatype.h                    |  6 ++++++
 .../corelib/kernel/qmetatype/tst_qmetatype.cpp    | 13 +++++++++++++
 .../tst_exceptionsafety_objects.cpp               |  5 -----
 tests/benchmarks/corelib/tools/qstring/main.cpp   | 15 ---------------
 5 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/src/corelib/io/qtextstream.h b/src/corelib/io/qtextstream.h
index e3686e10ef..3e1d0faa25 100644
--- a/src/corelib/io/qtextstream.h
+++ b/src/corelib/io/qtextstream.h
@@ -208,12 +208,6 @@ typedef void (QTextStream::*QTSMFI)(int); // manipulator w/int argument
 typedef void (QTextStream::*QTSMFC)(QChar); // manipulator w/QChar argument
 
 
-namespace QtPrivate {
-template <> struct IsPointerToTypeDerivedFromQObject<QTextStreamFunction> {
-    enum { Value = false };
-};
-}
-
 class Q_CORE_EXPORT QTextStreamManipulator
 {
 public:
diff --git a/src/corelib/kernel/qmetatype.h b/src/corelib/kernel/qmetatype.h
index fd5c5f30dd..0ea9d26394 100644
--- a/src/corelib/kernel/qmetatype.h
+++ b/src/corelib/kernel/qmetatype.h
@@ -365,6 +365,12 @@ namespace QtPrivate {
         Q_STATIC_ASSERT_X(sizeof(T), "Type argument of Q_DECLARE_METATYPE(T*) must be fully defined");
         enum { Value = sizeof(checkType(static_cast<T*>(0))) == sizeof(yes_type) };
     };
+
+    // Function pointers don't derive from QObject
+    template <class Result> struct IsPointerToTypeDerivedFromQObject<Result(*)()> { enum { Value = false }; };
+    template <class Result, class Arg0> struct IsPointerToTypeDerivedFromQObject<Result(*)(Arg0)> { enum { Value = false }; };
+    template <class Result, class Arg0, class Arg1> struct IsPointerToTypeDerivedFromQObject<Result(*)(Arg0, Arg1)> { enum { Value = false }; };
+    template <class Result, class Arg0, class Arg1, class Arg2> struct IsPointerToTypeDerivedFromQObject<Result(*)(Arg0, Arg1, Arg2)> { enum { Value = false }; };
 }
 
 template <typename T>
diff --git a/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp b/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp
index 82e59cef76..be13b39e7e 100644
--- a/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp
+++ b/tests/auto/corelib/kernel/qmetatype/tst_qmetatype.cpp
@@ -931,5 +931,18 @@ void tst_QMetaType::automaticTemplateRegistration()
   }
 }
 
+// Compile-time test, it should be possible to register function pointer types
+class Undefined;
+
+typedef Undefined (*UndefinedFunction0)();
+typedef Undefined (*UndefinedFunction1)(Undefined);
+typedef Undefined (*UndefinedFunction2)(Undefined, Undefined);
+typedef Undefined (*UndefinedFunction3)(Undefined, Undefined, Undefined);
+
+Q_DECLARE_METATYPE(UndefinedFunction0);
+Q_DECLARE_METATYPE(UndefinedFunction1);
+Q_DECLARE_METATYPE(UndefinedFunction2);
+Q_DECLARE_METATYPE(UndefinedFunction3);
+
 QTEST_MAIN(tst_QMetaType)
 #include "tst_qmetatype.moc"
diff --git a/tests/auto/other/exceptionsafety_objects/tst_exceptionsafety_objects.cpp b/tests/auto/other/exceptionsafety_objects/tst_exceptionsafety_objects.cpp
index e53582f178..71a70384fc 100644
--- a/tests/auto/other/exceptionsafety_objects/tst_exceptionsafety_objects.cpp
+++ b/tests/auto/other/exceptionsafety_objects/tst_exceptionsafety_objects.cpp
@@ -99,11 +99,6 @@ struct AbstractTester
 Q_DECLARE_METATYPE(AbstractTester *)
 
 typedef void (*TestFunction)(QObject*);
-QT_BEGIN_NAMESPACE namespace QtPrivate {
-template <> struct IsPointerToTypeDerivedFromQObject<TestFunction> {
-    enum { Value = false };
-};
-} QT_END_NAMESPACE
 Q_DECLARE_METATYPE(TestFunction)
 
 template <typename T>
diff --git a/tests/benchmarks/corelib/tools/qstring/main.cpp b/tests/benchmarks/corelib/tools/qstring/main.cpp
index ca72a9b013..9d5c43c290 100644
--- a/tests/benchmarks/corelib/tools/qstring/main.cpp
+++ b/tests/benchmarks/corelib/tools/qstring/main.cpp
@@ -1298,11 +1298,6 @@ static int ucstrncmp_ssse3_aligning2(const ushort *a, const ushort *b, int len)
 #endif
 
 typedef int (* UcstrncmpFunction)(const ushort *, const ushort *, int);
-QT_BEGIN_NAMESPACE namespace QtPrivate {
-template <> struct IsPointerToTypeDerivedFromQObject<UcstrncmpFunction> {
-    enum { Value = false };
-};
-} QT_END_NAMESPACE
 Q_DECLARE_METATYPE(UcstrncmpFunction)
 
 void tst_QString::ucstrncmp_data() const
@@ -1462,11 +1457,6 @@ void tst_QString::fromLatin1() const
 }
 
 typedef void (* FromLatin1Function)(ushort *, const char *, int);
-QT_BEGIN_NAMESPACE namespace QtPrivate {
-template <> struct IsPointerToTypeDerivedFromQObject<FromLatin1Function> {
-    enum { Value = false };
-};
-} QT_END_NAMESPACE
 Q_DECLARE_METATYPE(FromLatin1Function)
 
 void fromLatin1_regular(ushort *dst, const char *str, int size)
@@ -1917,11 +1907,6 @@ void tst_QString::fromLatin1Alternatives() const
 }
 
 typedef int (* FromUtf8Function)(ushort *, const char *, int);
-QT_BEGIN_NAMESPACE namespace QtPrivate {
-template <> struct IsPointerToTypeDerivedFromQObject<FromUtf8Function> {
-    enum { Value = false };
-};
-} QT_END_NAMESPACE
 Q_DECLARE_METATYPE(FromUtf8Function)
 
 extern QTextCodec::ConverterState *state;