Add some support to flag alias properties

This is required if we want to be able to get rid of the property
cache.

Also reserve a flag for var properties, in case it turns out that we
need to keep the distinction between var and QVariant properties in QML.

Change-Id: I55c2191adcc2d94bd8f148216e26423defaa900f
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

5 files changed, 42 insertions, 0 deletions

diff --git a/src/corelib/kernel/qmetaobject.cpp b/src/corelib/kernel/qmetaobject.cpp
index add1f3b86e..a94c0c7d5f 100644
--- a/src/corelib/kernel/qmetaobject.cpp
+++ b/src/corelib/kernel/qmetaobject.cpp
@@ -3033,6 +3033,20 @@ bool QMetaProperty::hasStdCppSet() const
 
 /*!
     \internal
+
+    Returns \c true if the property is an alias.
+    This is for instance true for a property declared in QML
+    as 'property alias'.
+*/
+bool QMetaProperty::isAlias() const
+{
+    if (!mobj)
+        return false;
+    return (data.flags() & Alias);
+}
+
+/*!
+    \internal
     Executes metacall with QMetaObject::RegisterPropertyMetaType flag.
     Returns id of registered type or QMetaType::UnknownType if a type
     could not be registered for any reason.
diff --git a/src/corelib/kernel/qmetaobject.h b/src/corelib/kernel/qmetaobject.h
index e9290e0844..474e4da0f1 100644
--- a/src/corelib/kernel/qmetaobject.h
+++ b/src/corelib/kernel/qmetaobject.h
@@ -314,6 +314,7 @@ public:
     bool resetOnGadget(void *gadget) const;
 
     bool hasStdCppSet() const;
+    bool isAlias() const;
     inline bool isValid() const { return isReadable(); }
     inline const QMetaObject *enclosingMetaObject() const { return mobj; }
 
diff --git a/src/corelib/kernel/qmetaobject_p.h b/src/corelib/kernel/qmetaobject_p.h
index 79d090cc4b..02ede4d376 100644
--- a/src/corelib/kernel/qmetaobject_p.h
+++ b/src/corelib/kernel/qmetaobject_p.h
@@ -71,6 +71,8 @@ enum PropertyFlags  {
     Writable = 0x00000002,
     Resettable = 0x00000004,
     EnumOrFlag = 0x00000008,
+    Alias = 0x00000010,
+    //Reserved for future usage = 0x00000020,
     StdCppSet = 0x00000100,
     Constant = 0x00000400,
     Final = 0x00000800,
diff --git a/src/corelib/kernel/qmetaobjectbuilder.cpp b/src/corelib/kernel/qmetaobjectbuilder.cpp
index 0f778af644..204ba8f51b 100644
--- a/src/corelib/kernel/qmetaobjectbuilder.cpp
+++ b/src/corelib/kernel/qmetaobjectbuilder.cpp
@@ -2368,6 +2368,19 @@ bool QMetaPropertyBuilder::isFinal() const
 }
 
 /*!
+ * Returns \c true if the property is an alias.
+ * The default value is false
+ */
+bool QMetaPropertyBuilder::isAlias() const
+{
+    QMetaPropertyBuilderPrivate *d = d_func();
+    if (d)
+        return d->flag(Alias);
+    else
+        return false;
+}
+
+/*!
     Sets this property to readable if \a value is true.
 
     \sa isReadable(), setWritable()
@@ -2503,6 +2516,16 @@ void QMetaPropertyBuilder::setFinal(bool value)
 }
 
 /*!
+   Sets the \c ALIAS flag on this property to \a value
+ */
+void QMetaPropertyBuilder::setAlias(bool value)
+{
+    QMetaPropertyBuilderPrivate *d = d_func();
+    if (d)
+        d->setFlag(Alias, value);
+}
+
+/*!
     Returns the revision of this property.
 
     \sa setRevision()
diff --git a/src/corelib/kernel/qmetaobjectbuilder_p.h b/src/corelib/kernel/qmetaobjectbuilder_p.h
index 974fbd4a64..a473e68cec 100644
--- a/src/corelib/kernel/qmetaobjectbuilder_p.h
+++ b/src/corelib/kernel/qmetaobjectbuilder_p.h
@@ -262,6 +262,7 @@ public:
     bool isEnumOrFlag() const;
     bool isConstant() const;
     bool isFinal() const;
+    bool isAlias() const;
 
     void setReadable(bool value);
     void setWritable(bool value);
@@ -274,6 +275,7 @@ public:
     void setEnumOrFlag(bool value);
     void setConstant(bool value);
     void setFinal(bool value);
+    void setAlias(bool value);
 
     int revision() const;
     void setRevision(int revision);