Add Context.Spawn.

Author: niemeyer

cpp/capi.cpp

@@ -327,6 +327,12 @@ void contextGetProperty(QQmlContext_ *context, QString_ *name, DataValue *result
     packDataValue(&var, result);
 }
 
+QQmlContext_ *contextSpawn(QQmlContext_ *context)
+{
+    QQmlContext *qcontext = reinterpret_cast<QQmlContext *>(context);
+    return new QQmlContext(qcontext);
+}
+
 void delObject(QObject_ *object)
 {
     delete reinterpret_cast<QObject *>(object);

cpp/capi.h

@@ -125,6 +125,7 @@ void engineAddImageProvider(QQmlEngine_ *engine, QString_ *providerId, void *ima
 void contextGetProperty(QQmlContext_ *context, QString_ *name, DataValue *value);
 void contextSetProperty(QQmlContext_ *context, QString_ *name, DataValue *value);
 void contextSetObject(QQmlContext_ *context, QObject_ *value);
+QQmlContext_ *contextSpawn(QQmlContext_ *context);
 
 void delObject(QObject_ *object);
 void delObjectLater(QObject_ *object);

qml.go

@@ -327,7 +327,15 @@ func (ctx *Context) Var(name string) interface{} {
 	return unpackDataValue(&dvalue, ctx.engine)
 }
 
-// TODO Context.Spawn() => Context
+// Spawn creates a new context that has ctx as a parent.
+func (ctx *Context) Spawn() *Context {
+	var result Context
+	result.engine = ctx.engine
+	RunMain(func() {
+		result.addr = C.contextSpawn(ctx.addr)
+	})
+	return &result
+}
 
 // Object is the common interface implemented by all QML types.
 //

qml_test.go

@@ -282,6 +282,27 @@ func (s *S) TestComponentCreateWindow(c *C) {
 	window.Hide()
 }
 
+func (s *S) TestContextSpawn(c *C) {
+	context1 := s.engine.Context()
+	context2 := context1.Spawn()
+
+	context1.SetVar("mystr", "context1")
+	context2.SetVar("mystr", "context2")
+
+	data := `
+		import QtQuick 2.0
+		Item { property var s: mystr }
+	`
+	component, err := s.engine.LoadString("file.qml", data)
+	c.Assert(err, IsNil)
+
+	obj1 := component.Create(context1)
+	obj2 := component.Create(context2)
+
+	c.Assert(obj1.String("s"), Equals, "context1")
+	c.Assert(obj2.String("s"), Equals, "context2")
+}
+
 func (s *S) TestReadVoidAddrProperty(c *C) {
 	obj := cpptest.NewTestType(s.engine)
 	addr := obj.Property("voidAddr").(uintptr)