From f800adc478591cff0a462ae51af105eebfb7a9f4 Mon Sep 17 00:00:00 2001 From: Uwe Hermann Date: Thu, 27 Jan 2011 20:56:39 +0100 Subject: Bugfix: PyTuple_SetItem() "steals" a reference. --- decode.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'decode.c') diff --git a/decode.c b/decode.c index 6acbd10..c2beab2 100644 --- a/decode.c +++ b/decode.c @@ -34,6 +34,19 @@ /* The list of protocol decoders. */ GSList *list_pds = NULL; +/* + * Here's a quick overview of Python/C API reference counting. + * + * Check the Python/C API docs for what type of reference a function returns. + * + * - If it returns a "new reference", you're responsible to Py_DECREF() it. + * + * - If it returns a "borrowed reference", you MUST NOT Py_DECREF() it. + * + * - If a function "steals" a reference, you no longer are responsible for + * Py_DECREF()ing it (someone else will do it for you at some point). + */ + /** * Initialize libsigrokdecode. * @@ -263,9 +276,14 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec, return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */ } + /* + * IMPORTANT: PyTuple_SetItem() "steals" a reference to py_value! + * That means we are no longer responsible for Py_DECREF()'ing it. + * It will automatically be free'd when the 'py_args' tuple is free'd. + */ if (PyTuple_SetItem(py_args, 0, py_value) != 0) { PyErr_Print(); - Py_DECREF(py_value); + Py_DECREF(py_value); /* TODO: Ref. stolen upon error? */ Py_DECREF(py_args); Py_DECREF(py_func); Py_DECREF(py_mod); @@ -274,7 +292,6 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec, if (!(py_res = PyObject_CallObject(py_func, py_args))) { PyErr_Print(); - Py_DECREF(py_value); Py_DECREF(py_args); Py_DECREF(py_func); Py_DECREF(py_mod); @@ -285,7 +302,6 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec, (Py_ssize_t *)outbuflen))) { PyErr_Print(); Py_DECREF(py_res); - Py_DECREF(py_value); Py_DECREF(py_args); Py_DECREF(py_func); Py_DECREF(py_mod); @@ -293,7 +309,6 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec, } Py_DECREF(py_res); - // Py_DECREF(py_value); Py_DECREF(py_args); Py_DECREF(py_func); Py_DECREF(py_mod); -- cgit v1.2.3-70-g09d2