Allow property bindings to be easily created from JavaScript

Properties can now be assigned a function that returns the binding
value.

Task-number: QTBUG-14964
Reviewed-by: Aaron Kennedy

9 files changed, 149 insertions, 17 deletions

diff --git a/src/declarative/qml/qdeclarativebinding.cpp b/src/declarative/qml/qdeclarativebinding.cpp
index b2d0738..a5bd604 100644
--- a/src/declarative/qml/qdeclarativebinding.cpp
+++ b/src/declarative/qml/qdeclarativebinding.cpp
@@ -274,6 +274,13 @@ QDeclarativeBinding::QDeclarativeBinding(const QString &str, QObject *obj, QDecl
     setNotifyOnValueChanged(true);
 }
 
+QDeclarativeBinding::QDeclarativeBinding(const QScriptValue &func, QObject *obj, QDeclarativeContextData *ctxt, QObject *parent)
+: QDeclarativeExpression(ctxt, obj, func, *new QDeclarativeBindingPrivate)
+{
+    setParent(parent);
+    setNotifyOnValueChanged(true);
+}
+
 QDeclarativeBinding::~QDeclarativeBinding()
 {
 }
@@ -292,6 +299,19 @@ QDeclarativeProperty QDeclarativeBinding::property() const
    return d->property; 
 }
 
+void QDeclarativeBinding::setEvaluateFlags(EvaluateFlags flags)
+{
+    Q_D(QDeclarativeBinding);
+    d->setEvaluateFlags(QDeclarativeQtScriptExpression::EvaluateFlags(static_cast<int>(flags)));
+}
+
+QDeclarativeBinding::EvaluateFlags QDeclarativeBinding::evaluateFlags() const
+{
+    Q_D(const QDeclarativeBinding);
+    return QDeclarativeBinding::EvaluateFlags(static_cast<int>(d->evaluateFlags()));
+}
+
+
 class QDeclarativeBindingProfiler {
 public:
     QDeclarativeBindingProfiler(QDeclarativeBinding *bind)
diff --git a/src/declarative/qml/qdeclarativebinding_p.h b/src/declarative/qml/qdeclarativebinding_p.h
index 19e7099..0260b95 100644
--- a/src/declarative/qml/qdeclarativebinding_p.h
+++ b/src/declarative/qml/qdeclarativebinding_p.h
@@ -147,14 +147,21 @@ class Q_DECLARATIVE_PRIVATE_EXPORT QDeclarativeBinding : public QDeclarativeExpr
 {
 Q_OBJECT
 public:
+    enum EvaluateFlag { RequiresThisObject = 0x01 };
+    Q_DECLARE_FLAGS(EvaluateFlags, EvaluateFlag)
+
     QDeclarativeBinding(const QString &, QObject *, QDeclarativeContext *, QObject *parent=0);
     QDeclarativeBinding(const QString &, QObject *, QDeclarativeContextData *, QObject *parent=0);
     QDeclarativeBinding(void *, QDeclarativeRefCount *, QObject *, QDeclarativeContextData *, 
                         const QString &, int, QObject *parent);
+    QDeclarativeBinding(const QScriptValue &, QObject *, QDeclarativeContextData *, QObject *parent=0);
 
     void setTarget(const QDeclarativeProperty &);
     QDeclarativeProperty property() const;
 
+    void setEvaluateFlags(EvaluateFlags flags);
+    EvaluateFlags evaluateFlags() const;
+
     bool enabled() const;
 
     // Inherited from  QDeclarativeAbstractBinding
@@ -177,6 +184,8 @@ private:
     Q_DECLARE_PRIVATE(QDeclarativeBinding)
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(QDeclarativeBinding::EvaluateFlags)
+
 QT_END_NAMESPACE
 
 Q_DECLARE_METATYPE(QDeclarativeBinding*)
diff --git a/src/declarative/qml/qdeclarativeexpression.cpp b/src/declarative/qml/qdeclarativeexpression.cpp
index 26c91a5..7a85ada 100644
--- a/src/declarative/qml/qdeclarativeexpression.cpp
+++ b/src/declarative/qml/qdeclarativeexpression.cpp
@@ -103,6 +103,19 @@ void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, const QS
     expressionFunctionValid = false;
 }
 
+void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, const QScriptValue &func,
+                                         QObject *me)
+{
+    expression = func.toString();
+
+    QDeclarativeAbstractExpression::setContext(ctxt);
+    scopeObject = me;
+
+    expressionFunction = func;
+    expressionFunctionMode = ExplicitContext;
+    expressionFunctionValid = true;
+}
+
 void QDeclarativeExpressionPrivate::init(QDeclarativeContextData *ctxt, void *expr, 
                                          QDeclarativeRefCount *rc, 
                                          QObject *me, const QString &srcUrl, int lineNumber)
@@ -304,6 +317,19 @@ QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QO
     d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
 }
 
+/*!  \internal */
+QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, QObject *scope, const QScriptValue &func,
+                       QDeclarativeExpressionPrivate &dd)
+: QObject(dd, 0)
+{
+    Q_D(QDeclarativeExpression);
+    d->init(ctxt, func, scope);
+
+    if (QDeclarativeExpression_notifyIdx == -1)
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
+}
+
 /*!
     Destroy the QDeclarativeExpression instance.
 */
@@ -412,6 +438,16 @@ void QDeclarativeQtScriptExpression::setNotifyObject(QObject *object, int notify
     }
 }
 
+void QDeclarativeQtScriptExpression::setEvaluateFlags(EvaluateFlags flags)
+{
+    evalFlags = flags;
+}
+
+QDeclarativeQtScriptExpression::EvaluateFlags QDeclarativeQtScriptExpression::evaluateFlags() const
+{
+    return evalFlags;
+}
+
 QScriptValue QDeclarativeQtScriptExpression::scriptValue(QObject *secondaryScope, bool *isUndefined)
 {
     Q_ASSERT(context() && context()->engine);
@@ -476,7 +512,10 @@ QScriptValue QDeclarativeQtScriptExpression::eval(QObject *secondaryScope, bool
         oldOverride = ep->contextClass->setOverrideObject(expressionContext, secondaryScope);
     }
 
-    QScriptValue svalue = expressionFunction.call(); // This could cause this to be deleted
+    QScriptValue thisObject;
+    if (evalFlags & RequiresThisObject)
+        thisObject = ep->objectClass->newQObject(scopeObject);
+    QScriptValue svalue = expressionFunction.call(thisObject); // This could cause this c++ object to be deleted
 
     if (isShared) {
         ep->sharedContext = oldSharedContext;
diff --git a/src/declarative/qml/qdeclarativeexpression.h b/src/declarative/qml/qdeclarativeexpression.h
index 72c5947..d40094b 100644
--- a/src/declarative/qml/qdeclarativeexpression.h
+++ b/src/declarative/qml/qdeclarativeexpression.h
@@ -59,6 +59,7 @@ class QDeclarativeEngine;
 class QDeclarativeContext;
 class QDeclarativeExpressionPrivate;
 class QDeclarativeContextData;
+class QScriptValue;
 class Q_DECLARATIVE_EXPORT QDeclarativeExpression : public QObject
 {
     Q_OBJECT
@@ -94,6 +95,8 @@ Q_SIGNALS:
 protected:
     QDeclarativeExpression(QDeclarativeContextData *, QObject *, const QString &,
                            QDeclarativeExpressionPrivate &dd);
+    QDeclarativeExpression(QDeclarativeContextData *, QObject *, const QScriptValue &,
+                           QDeclarativeExpressionPrivate &dd);
     QDeclarativeExpression(QDeclarativeContextData *, void *, QDeclarativeRefCount *rc, 
                            QObject *me, const QString &, int, QDeclarativeExpressionPrivate &dd);
 
diff --git a/src/declarative/qml/qdeclarativeexpression_p.h b/src/declarative/qml/qdeclarativeexpression_p.h
index 1d25609..51cae0f 100644
--- a/src/declarative/qml/qdeclarativeexpression_p.h
+++ b/src/declarative/qml/qdeclarativeexpression_p.h
@@ -113,6 +113,9 @@ class QDeclarativeQtScriptExpression : public QDeclarativeAbstractExpression,
 public:
     enum Mode { SharedContext, ExplicitContext };
 
+    enum EvaluateFlag { RequiresThisObject = 0x01 };
+    Q_DECLARE_FLAGS(EvaluateFlags, EvaluateFlag)
+
     QDeclarativeQtScriptExpression();
     virtual ~QDeclarativeQtScriptExpression();
 
@@ -131,6 +134,9 @@ public:
     void resetNotifyOnChange();
     void setNotifyObject(QObject *, int );
 
+    void setEvaluateFlags(EvaluateFlags flags);
+    EvaluateFlags evaluateFlags() const;
+
     QScriptValue scriptValue(QObject *secondaryScope, bool *isUndefined);
 
     class DeleteWatcher {
@@ -157,8 +163,13 @@ private:
     QObject *guardObject;
     int guardObjectNotifyIndex;
     bool *deleted;
+
+    EvaluateFlags evalFlags;
 };
 
+Q_DECLARE_OPERATORS_FOR_FLAGS(QDeclarativeQtScriptExpression::EvaluateFlags)
+
+
 class QDeclarativeExpression;
 class QString;
 class QDeclarativeExpressionPrivate : public QObjectPrivate, public QDeclarativeQtScriptExpression
@@ -169,6 +180,7 @@ public:
     ~QDeclarativeExpressionPrivate();
 
     void init(QDeclarativeContextData *, const QString &, QObject *);
+    void init(QDeclarativeContextData *, const QScriptValue &, QObject *);
     void init(QDeclarativeContextData *, void *, QDeclarativeRefCount *, QObject *, const QString &, int);
 
     QVariant value(QObject *secondaryScope = 0, bool *isUndefined = 0);
diff --git a/src/declarative/qml/qdeclarativeobjectscriptclass.cpp b/src/declarative/qml/qdeclarativeobjectscriptclass.cpp
index cbbf2b9..7701a23 100644
--- a/src/declarative/qml/qdeclarativeobjectscriptclass.cpp
+++ b/src/declarative/qml/qdeclarativeobjectscriptclass.cpp
@@ -359,8 +359,20 @@ void QDeclarativeObjectScriptClass::setProperty(QObject *obj,
         }
     }
 
+    QDeclarativeBinding *newBinding = 0;
+    if (value.isFunction() && !value.isRegExp()) {
+        QScriptContextInfo ctxtInfo(context);
+        QDeclarativePropertyCache::ValueTypeData valueTypeData;
+
+        newBinding = new QDeclarativeBinding(value, obj, evalContext);
+        newBinding->setSourceLocation(ctxtInfo.fileName(), ctxtInfo.functionStartLineNumber());
+        newBinding->setTarget(QDeclarativePropertyPrivate::restore(*lastData, valueTypeData, obj, evalContext));
+        if (newBinding->expression().contains("this"))
+            newBinding->setEvaluateFlags(newBinding->evaluateFlags() | QDeclarativeBinding::RequiresThisObject);
+    }
+
     QDeclarativeAbstractBinding *delBinding =
-        QDeclarativePropertyPrivate::setBinding(obj, lastData->coreIndex, -1, 0);
+        QDeclarativePropertyPrivate::setBinding(obj, lastData->coreIndex, -1, newBinding);
     if (delBinding)
         delBinding->destroy();
 
@@ -379,10 +391,7 @@ void QDeclarativeObjectScriptClass::setProperty(QObject *obj,
         QString error = QLatin1String("Cannot assign [undefined] to ") +
                         QLatin1String(QMetaType::typeName(lastData->propType));
         context->throwError(error);
-    } else if (!value.isRegExp() && value.isFunction()) {
-        QString error = QLatin1String("Cannot assign a function to a property.");
-        context->throwError(error);
-    } else {
+    } else if (!value.isFunction()) {
         QVariant v;
         if (lastData->flags & QDeclarativePropertyCache::Data::IsQList)
             v = enginePriv->scriptValueToVariant(value, qMetaTypeId<QList<QObject *> >());
diff --git a/src/declarative/qml/qdeclarativeproperty.cpp b/src/declarative/qml/qdeclarativeproperty.cpp
index 76829b7..61e3002 100644
--- a/src/declarative/qml/qdeclarativeproperty.cpp
+++ b/src/declarative/qml/qdeclarativeproperty.cpp
@@ -1480,19 +1480,28 @@ QDeclarativePropertyPrivate::restore(const QByteArray &data, QObject *object, QD
     if (data.isEmpty())
         return prop;
 
-    prop.d = new QDeclarativePropertyPrivate;
-    prop.d->object = object;
-    prop.d->context = ctxt;
-    prop.d->engine = ctxt->engine;
-
     const SerializedData *sd = (const SerializedData *)data.constData();
     if (sd->isValueType) {
         const ValueTypeSerializedData *vt = (const ValueTypeSerializedData *)sd;
-        prop.d->core = vt->core;
-        prop.d->valueType = vt->valueType;
+        return restore(vt->core, vt->valueType, object, ctxt);
     } else {
-        prop.d->core = sd->core;
+        QDeclarativePropertyCache::ValueTypeData data;
+        return restore(sd->core, data, object, ctxt);
     }
+}
+
+QDeclarativeProperty
+QDeclarativePropertyPrivate::restore(const QDeclarativePropertyCache::Data &data, const QDeclarativePropertyCache::ValueTypeData &valueType, QObject *object, QDeclarativeContextData *ctxt)
+{
+    QDeclarativeProperty prop;
+
+    prop.d = new QDeclarativePropertyPrivate;
+    prop.d->object = object;
+    prop.d->context = ctxt;
+    prop.d->engine = ctxt->engine;
+
+    prop.d->core = data;
+    prop.d->valueType = valueType;
 
     return prop;
 }
diff --git a/src/declarative/qml/qdeclarativeproperty_p.h b/src/declarative/qml/qdeclarativeproperty_p.h
index fa0fef4..bd2c891 100644
--- a/src/declarative/qml/qdeclarativeproperty_p.h
+++ b/src/declarative/qml/qdeclarativeproperty_p.h
@@ -112,7 +112,12 @@ public:
     static QByteArray saveValueType(const QMetaObject *, int, 
                                     const QMetaObject *, int);
     static QByteArray saveProperty(const QMetaObject *, int);
+
     static QDeclarativeProperty restore(const QByteArray &, QObject *, QDeclarativeContextData *);
+    static QDeclarativeProperty restore(const QDeclarativePropertyCache::Data &,
+                                        const QDeclarativePropertyCache::ValueTypeData &,
+                                        QObject *,
+                                        QDeclarativeContextData *);
 
     static bool equal(const QMetaObject *, const QMetaObject *);
     static bool canConvert(const QMetaObject *from, const QMetaObject *to);
diff --git a/src/declarative/qml/qdeclarativevaluetypescriptclass.cpp b/src/declarative/qml/qdeclarativevaluetypescriptclass.cpp
index 558ef90..200cc1c 100644
--- a/src/declarative/qml/qdeclarativevaluetypescriptclass.cpp
+++ b/src/declarative/qml/qdeclarativevaluetypescriptclass.cpp
@@ -46,6 +46,8 @@
 #include "private/qdeclarativeengine_p.h"
 #include "private/qdeclarativeguard_p.h"
 
+#include <QtScript/qscriptcontextinfo.h>
+
 QT_BEGIN_NAMESPACE
 
 struct QDeclarativeValueTypeObject : public QScriptDeclarativeClass::Object {
@@ -161,17 +163,41 @@ void QDeclarativeValueTypeScriptClass::setProperty(Object *obj, const Identifier
     if (o->objectType == QDeclarativeValueTypeObject::Reference) {
         QDeclarativeValueTypeReference *ref = static_cast<QDeclarativeValueTypeReference *>(obj);
 
+        ref->type->read(ref->object, ref->property);
+        QMetaProperty p = ref->type->metaObject()->property(m_lastIndex);
+
+        QDeclarativeBinding *newBinding = 0;
+        if (value.isFunction() && !value.isRegExp()) {
+            QDeclarativeContextData *ctxt = QDeclarativeEnginePrivate::get(engine)->getContext(context());
+
+            QDeclarativePropertyCache::Data cacheData;
+            cacheData.flags = QDeclarativePropertyCache::Data::IsWritable;
+            cacheData.propType = ref->object->metaObject()->property(ref->property).userType();
+            cacheData.coreIndex = ref->property;
+
+            QDeclarativePropertyCache::ValueTypeData valueTypeData;
+            valueTypeData.valueTypeCoreIdx = m_lastIndex;
+            valueTypeData.valueTypePropType = p.userType();
+
+            newBinding = new QDeclarativeBinding(value, ref->object, ctxt);
+            QScriptContextInfo ctxtInfo(context());
+            newBinding->setSourceLocation(ctxtInfo.fileName(), ctxtInfo.functionStartLineNumber());
+            QDeclarativeProperty prop = QDeclarativePropertyPrivate::restore(cacheData, valueTypeData, ref->object, ctxt);
+            newBinding->setTarget(prop);
+            if (newBinding->expression().contains("this"))
+                newBinding->setEvaluateFlags(newBinding->evaluateFlags() | QDeclarativeBinding::RequiresThisObject);
+        }
+
         QDeclarativeAbstractBinding *delBinding = 
-            QDeclarativePropertyPrivate::setBinding(ref->object, ref->property, m_lastIndex, 0);
+            QDeclarativePropertyPrivate::setBinding(ref->object, ref->property, m_lastIndex, newBinding);
         if (delBinding) 
             delBinding->destroy();
 
-        ref->type->read(ref->object, ref->property);
-        QMetaProperty p = ref->type->metaObject()->property(m_lastIndex);
         if (p.isEnumType() && (QMetaType::Type)v.type() == QMetaType::Double) 
             v = v.toInt();
         p.write(ref->type, v);
         ref->type->write(ref->object, ref->property, 0);
+
     } else {
         QDeclarativeValueTypeCopy *copy = static_cast<QDeclarativeValueTypeCopy *>(obj);
         copy->type->setValue(copy->value);