python: provide more C methods

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

Acked-by: Darren Hart <dvhltc@us.ibm.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>

1 files changed, 113 insertions, 0 deletions

diff --git a/ctracecmd.i b/ctracecmd.i
index ea62772..9569419 100644
--- a/ctracecmd.i
+++ b/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 */