Add support for parameterNames in Signals

There were many uses cases when a proper interaction
between Python and Qml was needed, one of them was
the case to emit signals from Python an get those values
via an argument name in QML.

A simple example describing this situation can be found
in PYSIDE-634:

Python:
    sumResult = Signal(int, arguments=["sum"])
    sumResult.emit(42)
Qml:
    onSumResult: console.log(sum) // will print 42

A test case based on the same example was added.

Change-Id: I0908f97d88eaadc0c02d81bc4daca936f72f6c6a
Fixes: PYSIDE-634
Reviewed-by: Christian Tismer <tismer@stackless.com>

1 files changed, 21 insertions, 2 deletions

diff --git a/sources/pyside2/libpyside/pysidesignal.cpp b/sources/pyside2/libpyside/pysidesignal.cpp
index 169028f0c..47a5fff43 100644
--- a/sources/pyside2/libpyside/pysidesignal.cpp
+++ b/sources/pyside2/libpyside/pysidesignal.cpp
@@ -203,14 +203,15 @@ PyTypeObject *PySideSignalInstanceTypeF(void)
 int signalTpInit(PyObject *self, PyObject *args, PyObject *kwds)
 {
     static PyObject *emptyTuple = nullptr;
-    static const char *kwlist[] = {"name", nullptr};
+    static const char *kwlist[] = {"name", "arguments", nullptr};
     char *argName = nullptr;
+    PyObject *argArguments = nullptr;
 
     if (emptyTuple == 0)
         emptyTuple = PyTuple_New(0);
 
     if (!PyArg_ParseTupleAndKeywords(emptyTuple, kwds,
-        "|s:QtCore." SIGNAL_CLASS_NAME, const_cast<char **>(kwlist), &argName))
+        "|sO:QtCore." SIGNAL_CLASS_NAME, const_cast<char **>(kwlist), &argName, &argArguments))
         return 0;
 
     bool tupledArgs = false;
@@ -220,6 +221,24 @@ int signalTpInit(PyObject *self, PyObject *args, PyObject *kwds)
     if (argName)
         data->data->signalName = argName;
 
+    data->data->signalArguments = new QByteArrayList();
+    if (argArguments && PySequence_Check(argArguments)) {
+        Py_ssize_t argument_size = PySequence_Size(argArguments);
+        for (Py_ssize_t i = 0; i < argument_size; ++i) {
+            PyObject *item = PySequence_GetItem(argArguments, i);
+#ifdef IS_PY3K
+            PyObject *strObj = PyUnicode_AsUTF8String(item);
+            char *s = PyBytes_AsString(strObj);
+            Py_DECREF(strObj);
+#else
+            char *s = PyBytes_AsString(item);
+#endif
+            Py_DECREF(item);
+            if (s != nullptr)
+                data->data->signalArguments->append(QByteArray(s));
+        }
+    }
+
     for (Py_ssize_t i = 0, i_max = PyTuple_Size(args); i < i_max; i++) {
         PyObject *arg = PyTuple_GET_ITEM(args, i);
         if (PySequence_Check(arg) && !Shiboken::String::check(arg)) {