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

3 files changed, 132 insertions, 15 deletions

diff --git a/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.2.qml b/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.2.qml
index 948b39c..c8c926a 100644
--- a/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.2.qml
+++ b/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.2.qml
@@ -1,13 +1,73 @@
 import Qt.test 1.0
+import QtQuick 1.0
+
+import "functionAssignment.js" as Script
 
 MyQmlObject {
     property variant a
-    property bool runTest: false
-    onRunTestChanged: {
+    property int aNumber: 10
+
+    property bool assignToProperty: false
+    property bool assignToPropertyFromJsFile: false
+
+    property bool assignWithThis: false
+    property bool assignWithThisFromJsFile: false
+
+    property bool assignToValueType: false
+
+    property bool assignFuncWithoutReturn: false
+    property bool assignWrongType: false
+    property bool assignWrongTypeToValueType: false
+
+
+    onAssignToPropertyChanged: {
+        function myFunction() {
+            return aNumber * 10;
+        }
+        a = myFunction;
+    }
+
+    property QtObject obj: QtObject {
+        property int aNumber: 4212
+        function myFunction() {
+            return this.aNumber * 10;   // should use the aNumber from root, not this object
+        }
+    }
+    onAssignWithThisChanged: {
+        a = obj.myFunction;
+    }
+
+    onAssignToPropertyFromJsFileChanged: {
+        Script.bindPropertyWithThis()
+    }
+
+    onAssignWithThisFromJsFileChanged: {
+        Script.bindProperty()
+    }
+
+    property Text text: Text { }
+    onAssignToValueTypeChanged: {
+        text.font.pixelSize = (function() { return aNumber * 10; })
+        a = (function() { return text.font.pixelSize; })
+    }
+
+
+    // detecting errors:
+
+    onAssignFuncWithoutReturnChanged: {
         function myFunction() {
-            console.log("hello world");
         }
         a = myFunction;
     }
 
+    onAssignWrongTypeChanged: {
+        function myFunction() {
+            return 'a string';
+        }
+        aNumber = myFunction;
+    }
+
+    onAssignWrongTypeToValueTypeChanged: {
+        text.font.pixelSize = (function() { return 'a string'; })
+    }
 }
diff --git a/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.js b/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.js
new file mode 100644
index 0000000..14daa76
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativeecmascript/data/functionAssignment.js
@@ -0,0 +1,17 @@
+function bindProperty()
+{
+    a = (function(){ return aNumber * 10 })
+}
+
+
+function TestObject() { }
+TestObject.prototype.aNumber = 928349
+TestObject.prototype.bindFunction = function() {
+    return this.aNumber * 10        // this should not use the TestObject's aNumber
+}
+var testObj = new TestObject()
+
+function bindPropertyWithThis()
+{
+    a = testObj.bindFunction
+}
diff --git a/tests/auto/declarative/qdeclarativeecmascript/tst_qdeclarativeecmascript.cpp b/tests/auto/declarative/qdeclarativeecmascript/tst_qdeclarativeecmascript.cpp
index cfe8cad..e7f9a2c 100644
--- a/tests/auto/declarative/qdeclarativeecmascript/tst_qdeclarativeecmascript.cpp
+++ b/tests/auto/declarative/qdeclarativeecmascript/tst_qdeclarativeecmascript.cpp
@@ -155,7 +155,10 @@ private slots:
     void qtcreatorbug_1289();
     void noSpuriousWarningsAtShutdown();
     void canAssignNullToQObject();
-    void functionAssignment();
+    void functionAssignment_fromBinding();
+    void functionAssignment_fromJS();
+    void functionAssignment_fromJS_data();
+    void functionAssignmentfromJS_invalid();
     void eval();
     void function();
     void qtbug_10696();
@@ -2514,9 +2517,8 @@ void tst_qdeclarativeecmascript::canAssignNullToQObject()
     }
 }
 
-void tst_qdeclarativeecmascript::functionAssignment()
+void tst_qdeclarativeecmascript::functionAssignment_fromBinding()
 {
-    {
     QDeclarativeComponent component(&engine, TEST_FILE("functionAssignment.1.qml"));
 
     QString url = component.url().toString();
@@ -2529,26 +2531,64 @@ void tst_qdeclarativeecmascript::functionAssignment()
     QVERIFY(!o->property("a").isValid());
 
     delete o;
-    }
+}
 
-    {
+void tst_qdeclarativeecmascript::functionAssignment_fromJS()
+{
+    QFETCH(QString, triggerProperty);
+
+    QDeclarativeComponent component(&engine, TEST_FILE("functionAssignment.2.qml"));
+    QVERIFY2(component.errorString().isEmpty(), qPrintable(component.errorString()));
+
+    MyQmlObject *o = qobject_cast<MyQmlObject *>(component.create());
+    QVERIFY(o != 0);
+    QVERIFY(!o->property("a").isValid());
+
+    o->setProperty("aNumber", QVariant(5));
+    o->setProperty(triggerProperty.toUtf8().constData(), true);
+    QCOMPARE(o->property("a"), QVariant(50));
+
+    o->setProperty("aNumber", QVariant(10));
+    QCOMPARE(o->property("a"), QVariant(100));
+
+    delete o;
+}
+
+void tst_qdeclarativeecmascript::functionAssignment_fromJS_data()
+{
+    QTest::addColumn<QString>("triggerProperty");
+
+    QTest::newRow("assign to property") << "assignToProperty";
+    QTest::newRow("assign to property, from JS file") << "assignToPropertyFromJsFile";
+
+    QTest::newRow("assign to value type") << "assignToValueType";
+
+    QTest::newRow("use 'this'") << "assignWithThis";
+    QTest::newRow("use 'this' from JS file") << "assignWithThisFromJsFile";
+}
+
+void tst_qdeclarativeecmascript::functionAssignmentfromJS_invalid()
+{
     QDeclarativeComponent component(&engine, TEST_FILE("functionAssignment.2.qml"));
+    QVERIFY2(component.errorString().isEmpty(), qPrintable(component.errorString()));
 
     MyQmlObject *o = qobject_cast<MyQmlObject *>(component.create());
     QVERIFY(o != 0);
+    QVERIFY(!o->property("a").isValid());
 
+    o->setProperty("assignFuncWithoutReturn", true);
     QVERIFY(!o->property("a").isValid());
-    
+
     QString url = component.url().toString();
-    QString warning = url + ":10: Error: Cannot assign a function to a property.";
+    QString warning = url + ":63: Unable to assign QString to int";
     QTest::ignoreMessage(QtWarningMsg, warning.toLatin1().constData());
-    
-    o->setProperty("runTest", true);
-    
-    QVERIFY(!o->property("a").isValid());
+    o->setProperty("assignWrongType", true);
+
+    warning = url + ":70: Unable to assign QString to int";
+    QTest::ignoreMessage(QtWarningMsg, warning.toLatin1().constData());
+    o->setProperty("assignWrongTypeToValueType", true);
 
     delete o;
-    }
 }
 
 void tst_qdeclarativeecmascript::eval()