Improve connect: Use existing metatypes if possible

As there is now a chance that a QMetaMethod already contains the
metatypes for its arguments, we can just query it directly (and use the
fallback to name lookup logic that already exists there).
This also allows us to avoid creating a QList of names, and only
requires us to do a name lookup in case the connection actually fails.

Change-Id: Idda30bc4b538a94476ae6c533776c22340f0030d
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

3 files changed, 38 insertions, 15 deletions

diff --git a/src/corelib/kernel/qmetaobject.cpp b/src/corelib/kernel/qmetaobject.cpp
index e584fbba8e..f0cef22b6f 100644
--- a/src/corelib/kernel/qmetaobject.cpp
+++ b/src/corelib/kernel/qmetaobject.cpp
@@ -207,6 +207,7 @@ public:
     inline uint parameterTypeInfo(int index) const;
     inline int parameterType(int index) const;
     inline void getParameterTypes(int *types) const;
+    inline QByteArray parameterTypeName(int index) const;
     inline QList<QByteArray> parameterTypes() const;
     inline QList<QByteArray> parameterNames() const;
     inline QByteArray tag() const;
@@ -1780,6 +1781,12 @@ void QMetaMethodPrivate::getParameterTypes(int *types) const
     }
 }
 
+QByteArray QMetaMethodPrivate::parameterTypeName(int index) const
+{
+    int paramsIndex = parametersDataIndex();
+    return typeNameFromTypeInfo(mobj, mobj->d.data[paramsIndex + index]);
+}
+
 QList<QByteArray> QMetaMethodPrivate::parameterTypes() const
 {
     Q_ASSERT(priv(mobj->d.data)->revision >= 7);
@@ -1961,6 +1968,20 @@ QList<QByteArray> QMetaMethod::parameterTypes() const
 }
 
 /*!
+   \since 6.0
+   Returns the name of the type at position \a index
+   If there is no parameter at \a index, returns an empty QByteArray
+
+   \sa parameterNames()
+ */
+QByteArray QMetaMethod::parameterTypeName(int index) const
+{
+    if (!mobj || index < 0 || index >= parameterCount())
+        return {};
+    return QMetaMethodPrivate::get(this)->parameterTypeName(index);
+}
+
+/*!
     Returns a list of parameter names.
 
     \sa parameterTypes(), methodSignature()
diff --git a/src/corelib/kernel/qmetaobject.h b/src/corelib/kernel/qmetaobject.h
index d013bfce65..8136e04dc9 100644
--- a/src/corelib/kernel/qmetaobject.h
+++ b/src/corelib/kernel/qmetaobject.h
@@ -63,6 +63,7 @@ public:
     QMetaType parameterMetaType(int index) const;
     void getParameterTypes(int *types) const;
     QList<QByteArray> parameterTypes() const;
+    QByteArray parameterTypeName(int index) const;
     QList<QByteArray> parameterNames() const;
     const char *tag() const;
     enum Access { Private, Protected, Public };
diff --git a/src/corelib/kernel/qobject.cpp b/src/corelib/kernel/qobject.cpp
index 1b8646947e..54229a9f71 100644
--- a/src/corelib/kernel/qobject.cpp
+++ b/src/corelib/kernel/qobject.cpp
@@ -95,28 +95,29 @@ QAbstractDynamicMetaObject::~QAbstractDynamicMetaObject()
 {
 }
 
-static int *queuedConnectionTypes(const QList<QByteArray> &typeNames)
+static int *queuedConnectionTypes(const QMetaMethod& method)
 {
-    int *types = new int [typeNames.count() + 1];
-    Q_CHECK_PTR(types);
-    for (int i = 0; i < typeNames.count(); ++i) {
-        const QByteArray typeName = typeNames.at(i);
-        if (typeName.endsWith('*'))
-            types[i] = QMetaType::VoidStar;
+    const auto parameterCount = method.parameterCount();
+    int *typeIds = new int [parameterCount + 1];
+    Q_CHECK_PTR(typeIds);
+    for (int i = 0; i < parameterCount; ++i) {
+        const QMetaType metaType = method.parameterMetaType(i);
+        if (metaType.flags() & QMetaType::IsPointer)
+            typeIds[i] = QMetaType::VoidStar;
         else
-            types[i] = QMetaType::fromName(typeName).id();
-
-        if (!types[i]) {
+            typeIds[i] = metaType.id();
+        if (!typeIds[i]) {
+            const QByteArray typeName = method.parameterTypeName(i);
             qWarning("QObject::connect: Cannot queue arguments of type '%s'\n"
                      "(Make sure '%s' is registered using qRegisterMetaType().)",
                      typeName.constData(), typeName.constData());
-            delete [] types;
+            delete [] typeIds;
             return nullptr;
         }
     }
-    types[typeNames.count()] = 0;
+    typeIds[parameterCount] = 0;
 
-    return types;
+    return typeIds;
 }
 
 static int *queuedConnectionTypes(const QArgumentType *argumentTypes, int argc)
@@ -2871,7 +2872,7 @@ QMetaObject::Connection QObject::connect(const QObject *sender, const QMetaMetho
 
     int *types = nullptr;
     if ((type == Qt::QueuedConnection)
-            && !(types = queuedConnectionTypes(signal.parameterTypes())))
+            && !(types = queuedConnectionTypes(signal)))
         return QMetaObject::Connection(nullptr);
 
 #ifndef QT_NO_DEBUG
@@ -3615,7 +3616,7 @@ static void queued_activate(QObject *sender, int signal, QObjectPrivate::Connect
     const int *argumentTypes = c->argumentTypes.loadRelaxed();
     if (!argumentTypes) {
         QMetaMethod m = QMetaObjectPrivate::signal(sender->metaObject(), signal);
-        argumentTypes = queuedConnectionTypes(m.parameterTypes());
+        argumentTypes = queuedConnectionTypes(m);
         if (!argumentTypes) // cannot queue arguments
             argumentTypes = &DIRECT_CONNECTION_ONLY;
         if (!c->argumentTypes.testAndSetOrdered(nullptr, argumentTypes)) {