qml: Override the new Object::instanceOf hook to allow QML type checking

[ChangeLog][QtQml] The instanceof keyword in JavaScript has been
extended to work on QML types and instances. This means that you are now
able to use it to verify that a var is indeed the type you expect (e.g.
someVar instanceof Rectangle).

Note that one of the added tests revealed a slight shortcoming in the
QML type system (QTBUG-58477). For now, we should keep consistency and
work to address the problem universally in the future.

Change-Id: I7d9bf9b64cfd037908de1ae51b01065eacb95abe
Task-number: QTBUG-24799
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

10 files changed, 309 insertions, 1 deletions

diff --git a/tests/auto/qml/qqmllanguage/data/instanceOf/CustomMouseArea.qml b/tests/auto/qml/qqmllanguage/data/instanceOf/CustomMouseArea.qml
new file mode 100644
index 0000000000..f6ec5848c1
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceOf/CustomMouseArea.qml
@@ -0,0 +1,6 @@
+import QtQuick 2.6
+
+MouseArea {
+
+}
+
diff --git a/tests/auto/qml/qqmllanguage/data/instanceOf/CustomRectangle.qml b/tests/auto/qml/qqmllanguage/data/instanceOf/CustomRectangle.qml
new file mode 100644
index 0000000000..b3fa43a671
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceOf/CustomRectangle.qml
@@ -0,0 +1,4 @@
+import QtQuick 2.6
+
+Rectangle {
+}
diff --git a/tests/auto/qml/qqmllanguage/data/instanceOf/CustomRectangleWithProp.qml b/tests/auto/qml/qqmllanguage/data/instanceOf/CustomRectangleWithProp.qml
new file mode 100644
index 0000000000..cf566b9315
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceOf/CustomRectangleWithProp.qml
@@ -0,0 +1,6 @@
+import QtQuick 2.6
+
+Rectangle {
+    property int somethingCustom: 0
+}
+
diff --git a/tests/auto/qml/qqmllanguage/data/instanceOf/qmldir b/tests/auto/qml/qqmllanguage/data/instanceOf/qmldir
new file mode 100644
index 0000000000..144c93d8e3
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceOf/qmldir
@@ -0,0 +1,2 @@
+CustomRectangle 1.0 CustomRectangle.qml
+CustomMouseArea 1.0 CustomMouseArea.qml
diff --git a/tests/auto/qml/qqmllanguage/data/instanceof_qtqml.qml b/tests/auto/qml/qqmllanguage/data/instanceof_qtqml.qml
new file mode 100644
index 0000000000..d74b172cf8
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceof_qtqml.qml
@@ -0,0 +1,13 @@
+import QtQml 2.0
+
+QtObject {
+    id: qtobjectInstance
+
+    property Timer aTimer: Timer {
+        id: timerInstance
+    }
+
+    property Connections aConnections: Connections {
+        id: connectionsInstance
+    }
+}
diff --git a/tests/auto/qml/qqmllanguage/data/instanceof_qtqml_qualified.qml b/tests/auto/qml/qqmllanguage/data/instanceof_qtqml_qualified.qml
new file mode 100644
index 0000000000..a8e303363e
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceof_qtqml_qualified.qml
@@ -0,0 +1,13 @@
+import QtQml 2.0 as QmlImport
+
+QmlImport.QtObject {
+    id: qtobjectInstance
+
+    property QmlImport.Timer aTimer: QmlImport.Timer {
+        id: timerInstance
+    }
+
+    property QmlImport.Connections aConnections: QmlImport.Connections {
+        id: connectionsInstance
+    }
+}
diff --git a/tests/auto/qml/qqmllanguage/data/instanceof_qtquick.qml b/tests/auto/qml/qqmllanguage/data/instanceof_qtquick.qml
new file mode 100644
index 0000000000..9c1808d515
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceof_qtquick.qml
@@ -0,0 +1,14 @@
+import QtQuick 2.0
+
+Item {
+    id: itemInstance
+
+    Rectangle {
+        id: rectangleInstance
+    }
+
+    MouseArea {
+        id: mouseAreaInstance
+    }
+}
+
diff --git a/tests/auto/qml/qqmllanguage/data/instanceof_qtquick_composite.qml b/tests/auto/qml/qqmllanguage/data/instanceof_qtquick_composite.qml
new file mode 100644
index 0000000000..78fc112805
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceof_qtquick_composite.qml
@@ -0,0 +1,26 @@
+import QtQuick 2.0
+import "instanceOf"
+
+Item {
+    id: itemInstance
+
+    Rectangle {
+        id: rectangleInstance
+    }
+
+    MouseArea {
+        id: mouseAreaInstance
+    }
+
+    CustomRectangle {
+        id: customRectangleInstance
+    }
+    CustomRectangleWithProp {
+        id: customRectangleWithPropInstance
+    }
+    CustomMouseArea {
+        id: customMouseAreaInstance
+    }
+}
+
+
diff --git a/tests/auto/qml/qqmllanguage/data/instanceof_qtquick_composite_qualified.qml b/tests/auto/qml/qqmllanguage/data/instanceof_qtquick_composite_qualified.qml
new file mode 100644
index 0000000000..97361b7334
--- /dev/null
+++ b/tests/auto/qml/qqmllanguage/data/instanceof_qtquick_composite_qualified.qml
@@ -0,0 +1,27 @@
+import QtQuick 2.0 as QuickImport
+import "instanceOf" as CustomImport
+
+QuickImport.Item {
+    id: itemInstance
+
+    QuickImport.Rectangle {
+        id: rectangleInstance
+    }
+
+    QuickImport.MouseArea {
+        id: mouseAreaInstance
+    }
+
+    CustomImport.CustomRectangle {
+        id: customRectangleInstance
+    }
+    CustomImport.CustomRectangleWithProp {
+        id: customRectangleWithPropInstance
+    }
+    CustomImport.CustomMouseArea {
+        id: customMouseAreaInstance
+    }
+}
+
+
+
diff --git a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
index 750c32cc3c..e67fa18309 100644
--- a/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
+++ b/tests/auto/qml/qqmllanguage/tst_qqmllanguage.cpp
@@ -263,6 +263,9 @@ private slots:
     void qmlTypeCanBeResolvedByName_data();
     void qmlTypeCanBeResolvedByName();
 
+    void instanceof_data();
+    void instanceof();
+
 private:
     QQmlEngine engine;
     QStringList defaultImportPathList;
@@ -309,7 +312,7 @@ private:
     if (!errorfile) { \
         if (qgetenv("DEBUG") != "" && !component.errors().isEmpty()) \
             qWarning() << "Unexpected Errors:" << component.errors(); \
-        QVERIFY(!component.isError()); \
+        QVERIFY2(!component.isError(), qPrintable(component.errorString())); \
         QVERIFY(component.errors().isEmpty()); \
     } else { \
         DETERMINE_ERRORS(errorfile,expected,actual);\
@@ -4338,6 +4341,200 @@ void tst_qqmllanguage::qmlTypeCanBeResolvedByName()
     QVERIFY(!o.isNull());
 }
 
+// Tests for the QML-only extensions of instanceof. Tests for the regular JS
+// instanceof belong in tst_qqmlecmascript!
+void tst_qqmllanguage::instanceof_data()
+{
+    QTest::addColumn<QUrl>("documentToTestIn");
+    QTest::addColumn<QVariant>("expectedValue");
+
+    // so the way this works is that the name of the test tag defines the test
+    // to run.
+    //
+    // the expectedValue is either a boolean true or false for whether the two
+    // operands are indeed an instanceof each other, or a string for the
+    // expected error message.
+
+    // assert that basic types don't convert to QObject
+    QTest::newRow("1 instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant("TypeError: Type error");
+    QTest::newRow("true instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant("TypeError: Type error");
+    QTest::newRow("\"foobar\" instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant("TypeError: Type error");
+
+    // assert that Managed don't either
+    QTest::newRow("new String(\"foobar\") instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant("TypeError: Type error");
+    QTest::newRow("new Object() instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant("TypeError: Type error");
+    QTest::newRow("new Date() instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant("TypeError: Type error");
+
+    // test that simple QtQml comparisons work
+    QTest::newRow("qtobjectInstance instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(true);
+    QTest::newRow("qtobjectInstance instanceof Timer")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(false);
+    QTest::newRow("timerInstance instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(true);
+    QTest::newRow("timerInstance instanceof Timer")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(true);
+    QTest::newRow("connectionsInstance instanceof QtObject")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(true);
+    QTest::newRow("connectionsInstance instanceof Timer")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(false);
+    QTest::newRow("connectionsInstance instanceof Connections")
+        << testFileUrl("instanceof_qtqml.qml")
+        << QVariant(true);
+
+    // make sure they still work when imported with a qualifier
+    QTest::newRow("qtobjectInstance instanceof QmlImport.QtObject")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("qtobjectInstance instanceof QmlImport.Timer")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(false);
+    QTest::newRow("timerInstance instanceof QmlImport.QtObject")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("timerInstance instanceof QmlImport.Timer")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("connectionsInstance instanceof QmlImport.QtObject")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("connectionsInstance instanceof QmlImport.Timer")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(false);
+    QTest::newRow("connectionsInstance instanceof QmlImport.Connections")
+        << testFileUrl("instanceof_qtqml_qualified.qml")
+        << QVariant(true);
+
+    // test that Quick C++ types work ok
+    QTest::newRow("itemInstance instanceof QtObject")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(true);
+    QTest::newRow("itemInstance instanceof Timer")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(false);
+    QTest::newRow("itemInstance instanceof Rectangle")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(false);
+    QTest::newRow("rectangleInstance instanceof Item")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(true);
+    QTest::newRow("rectangleInstance instanceof Rectangle")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(true);
+    QTest::newRow("rectangleInstance instanceof MouseArea")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(false);
+    QTest::newRow("mouseAreaInstance instanceof Item")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(true);
+    QTest::newRow("mouseAreaInstance instanceof Rectangle")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(false);
+    QTest::newRow("mouseAreaInstance instanceof MouseArea")
+        << testFileUrl("instanceof_qtquick.qml")
+        << QVariant(true);
+
+    // test that unqualified quick composite types work ok
+    QTest::newRow("rectangleInstance instanceof CustomRectangle")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(false);
+    QTest::newRow("customRectangleInstance instanceof Rectangle")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleInstance instanceof Item")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleWithPropInstance instanceof CustomRectangleWithProp")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleWithPropInstance instanceof CustomRectangle")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(false); // ### XXX: QTBUG-58477
+    QTest::newRow("customRectangleWithPropInstance instanceof Rectangle")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleInstance instanceof MouseArea")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(false);
+    QTest::newRow("customMouseAreaInstance instanceof MouseArea")
+        << testFileUrl("instanceof_qtquick_composite.qml")
+        << QVariant(true);
+
+    // test that they still work when qualified
+    QTest::newRow("rectangleInstance instanceof CustomImport.CustomRectangle")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(false);
+    QTest::newRow("customRectangleInstance instanceof QuickImport.Rectangle")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleInstance instanceof QuickImport.Item")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleWithPropInstance instanceof CustomImport.CustomRectangleWithProp")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleWithPropInstance instanceof CustomImport.CustomRectangle")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(false); // ### XXX: QTBUG-58477
+    QTest::newRow("customRectangleWithPropInstance instanceof QuickImport.Rectangle")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(true);
+    QTest::newRow("customRectangleInstance instanceof QuickImport.MouseArea")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(false);
+    QTest::newRow("customMouseAreaInstance instanceof QuickImport.MouseArea")
+        << testFileUrl("instanceof_qtquick_composite_qualified.qml")
+        << QVariant(true);
+}
+
+void tst_qqmllanguage::instanceof()
+{
+    QFETCH(QUrl, documentToTestIn);
+    QFETCH(QVariant, expectedValue);
+
+    QQmlEngine engine;
+    QQmlComponent component(&engine, documentToTestIn);
+    VERIFY_ERRORS(0);
+
+    QScopedPointer<QObject> o(component.create());
+    QVERIFY(o != 0);
+
+    QQmlExpression expr(engine.contextForObject(o.data()), 0, QString::fromLatin1(QTest::currentDataTag()));
+    QVariant ret = expr.evaluate();
+
+    if (expectedValue.type() == QVariant::Bool) {
+        // no error expected
+        QVERIFY2(!expr.hasError(), qPrintable(expr.error().description()));
+        bool returnValue = ret.toBool();
+
+        if (QTest::currentDataTag() == QLatin1String("customRectangleWithPropInstance instanceof CustomRectangle") ||
+            QTest::currentDataTag() == QLatin1String("customRectangleWithPropInstance instanceof CustomImport.CustomRectangle"))
+            QEXPECT_FAIL("", "QTBUG-58477: QML type rules are a little lax", Continue);
+        QCOMPARE(returnValue, expectedValue.toBool());
+    } else {
+        QVERIFY(expr.hasError());
+        QCOMPARE(expr.error().description(), expectedValue.toString());
+    }
+}
+
 QTEST_MAIN(tst_qqmllanguage)
 
 #include "tst_qqmllanguage.moc"