python: provide more C methods

This provides the C methods for wrapping
callbacks and the upcoming Event/Field
classes.

Acked-by: Darren Hart <[email protected]>
Signed-off-by: Johannes Berg <[email protected]>

ctracecmd.i

@@ -17,6 +17,119 @@
 #include "trace-cmd.h"
 %}
 
+
+%typemap(in) PyObject *pyfunc {
+	if (!PyCallable_Check($input)) {
+		PyErr_SetString(PyExc_TypeError, "Need a callable object!");
+		return NULL;
+	}
+	$1 = $input;
+}
+
+%ignore python_callback;
+
+%inline %{
+static int python_callback(struct trace_seq *s,
+			   struct record *record,
+			   struct event_format *event,
+			   void *context);
+
+void py_pevent_register_event_handler(struct pevent *pevent, int id,
+				      char *subsys, char *evname,
+				      PyObject *pyfunc)
+{
+	Py_INCREF(pyfunc);
+	pevent_register_event_handler(pevent, id, subsys, evname,
+				      python_callback, pyfunc);
+}
+
+static PyObject *py_field_get_data(struct format_field *f, struct record *r)
+{
+	if (!strncmp(f->type, "__data_loc ", 11)) {
+		unsigned long long val;
+		int len, offset;
+
+		if (pevent_read_number_field(f, r->data, &val)) {
+			PyErr_SetString(PyExc_TypeError,
+					"Field is not a valid number");
+			return NULL;
+		}
+
+		/*
+		 * The actual length of the dynamic array is stored
+		 * in the top half of the field, and the offset
+		 * is in the bottom half of the 32 bit field.
+		 */
+		offset = val & 0xffff;
+		len = val >> 16;
+
+		return PyBuffer_FromMemory((char *)r->data + offset, len);
+	}
+
+	return PyBuffer_FromMemory((char *)r->data + f->offset, f->size);
+}
+
+static PyObject *py_format_get_keys(struct event_format *ef)
+{
+	PyObject *list;
+	struct format_field *f;
+
+	list = PyList_New(0);
+
+	for (f = ef->format.fields; f; f = f->next) {
+		if (PyList_Append(list, PyString_FromString(f->name))) {
+			Py_DECREF(list);
+			return NULL;
+		}
+	}
+
+	return list;
+}
+%}
+
+
+%wrapper %{
+static int python_callback(struct trace_seq *s,
+			   struct record *record,
+			   struct event_format *event,
+			   void *context)
+{
+	PyObject *arglist, *result;
+	int r = 0;
+
+	record->ref_count++;
+
+	arglist = Py_BuildValue("(OOO)",
+		SWIG_NewPointerObj(SWIG_as_voidptr(s),
+				   SWIGTYPE_p_trace_seq, 0),
+		SWIG_NewPointerObj(SWIG_as_voidptr(record),
+				   SWIGTYPE_p_record, 0),
+		SWIG_NewPointerObj(SWIG_as_voidptr(event),
+				   SWIGTYPE_p_event_format, 0));
+
+	result = PyEval_CallObject(context, arglist);
+	Py_XDECREF(arglist);
+	if (result && result != Py_None) {
+		if (!PyInt_Check(result)) {
+			PyErr_SetString(PyExc_TypeError,
+					"callback must return int");
+			PyErr_Print();
+			Py_XDECREF(result);
+			return 0;
+		}
+		r = PyInt_AS_LONG(result);
+	} else if (result == Py_None)
+		r = 0;
+	else
+		PyErr_Print();
+
+	Py_XDECREF(result);
+
+	return r;
+}
+%}
+
+
 %ignore trace_seq_vprintf;
 
 /* SWIG can't grok these, define them to nothing */