decode.c: Better documentation.

Mark all Python/C API functions returning a new reference with "NEWREF",
and those that steal references with "STEAL".

diff --git a/decode.c b/decode.c
index 59cbadcfad66e0466072fb7e9bc05ae8b1eb9ad6..db29494523eb867af0d6334376ab94862f67841a 100644 (file)
--- a/decode.c
+++ b/decode.c
@@ -111,15 +111,20 @@ static int h_str(PyObject *py_res, PyObject *py_func, PyObject *py_mod,
        py_str = PyMapping_GetItemString(py_res, (char *)key);
        if (!py_str || !PyString_Check(py_str)) {
                if (PyErr_Occurred())
-                       PyErr_Print();
+                       PyErr_Print(); /* Returns void. */
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
        }
 
+       /*
+        * PyString_AsString()'s returned string refers to an internal buffer
+        * (not a copy), i.e. the data must not be modified, and the memory
+        * must not be free()'d.
+        */
        if (!(str = PyString_AsString(py_str))) {
                if (PyErr_Occurred())
-                       PyErr_Print();
+                       PyErr_Print(); /* Returns void. */
                Py_DECREF(py_str);
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
@@ -128,7 +133,7 @@ static int h_str(PyObject *py_res, PyObject *py_func, PyObject *py_mod,
 
        if (!(*outstr = strdup(str))) {
                if (PyErr_Occurred())
-                       PyErr_Print();
+                       PyErr_Print(); /* Returns void. */
                Py_DECREF(py_str);
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
@@ -155,31 +160,31 @@ int sigrokdecode_load_decoder(const char *name,
        int r;
 
        /* Get the name of the decoder module as Python string. */
-       if (!(py_name = PyString_FromString(name))) {
-               PyErr_Print();
+       if (!(py_name = PyString_FromString(name))) { /* NEWREF */
+               PyErr_Print(); /* Returns void. */
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
        }
 
        /* "Import" the Python module. */
-       if (!(py_mod = PyImport_Import(py_name))) {
-               PyErr_Print();
+       if (!(py_mod = PyImport_Import(py_name))) { /* NEWREF */
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_name);
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
        }
        Py_DECREF(py_name);
 
        /* Get the 'register' function name as Python callable object. */
-       py_func = PyObject_GetAttrString(py_mod, "register");
+       py_func = PyObject_GetAttrString(py_mod, "register"); /* NEWREF */
        if (!py_func || !PyCallable_Check(py_func)) {
                if (PyErr_Occurred())
-                       PyErr_Print();
+                       PyErr_Print(); /* Returns void. */
                Py_DECREF(py_mod);
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
        }
 
        /* Call the 'register' function without arguments, get the result. */
-       if (!(py_res = PyObject_CallFunction(py_func, NULL))) {
-               PyErr_Print();
+       if (!(py_res = PyObject_CallFunction(py_func, NULL))) { /* NEWREF */
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
@@ -203,10 +208,10 @@ int sigrokdecode_load_decoder(const char *name,
        Py_DECREF(py_func);
 
        /* Get the 'decode' function name as Python callable object. */
-       py_func = PyObject_GetAttrString(py_mod, "decode");
+       py_func = PyObject_GetAttrString(py_mod, "decode"); /* NEWREF */
        if (!py_func || !PyCallable_Check(py_func)) {
                if (PyErr_Occurred())
-                       PyErr_Print();
+                       PyErr_Print(); /* Returns void. */
                Py_DECREF(py_mod);
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
        }
@@ -259,8 +264,8 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec,
        /* TODO: Really run Py_DECREF on py_mod/py_func? */
 
        /* Create a Python tuple of size 1. */
-       if (!(py_args = PyTuple_New(1))) {
-               PyErr_Print();
+       if (!(py_args = PyTuple_New(1))) { /* NEWREF */
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
@@ -268,8 +273,8 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec,
 
        /* Get the input buffer as Python "string" (byte array). */
        /* TODO: int vs. uint64_t for 'inbuflen'? */
-       if (!(py_value = Py_BuildValue("s#", inbuf, inbuflen))) {
-               PyErr_Print();
+       if (!(py_value = Py_BuildValue("s#", inbuf, inbuflen))) { /* NEWREF */
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_args);
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
@@ -281,8 +286,8 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec,
         * 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();
+       if (PyTuple_SetItem(py_args, 0, py_value) != 0) { /* STEAL */
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_value); /* TODO: Ref. stolen upon error? */
                Py_DECREF(py_args);
                Py_DECREF(py_func);
@@ -290,8 +295,8 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec,
                return SIGROKDECODE_ERR_PYTHON; /* TODO: More specific error? */
        }
 
-       if (!(py_res = PyObject_CallObject(py_func, py_args))) {
-               PyErr_Print();
+       if (!(py_res = PyObject_CallObject(py_func, py_args))) { /* NEWREF */
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_args);
                Py_DECREF(py_func);
                Py_DECREF(py_mod);
@@ -300,7 +305,7 @@ int sigrokdecode_run_decoder(struct sigrokdecode_decoder *dec,
 
        if ((ret = PyObject_AsCharBuffer(py_res, (const char **)outbuf,
                                         (Py_ssize_t *)outbuflen))) {
-               PyErr_Print();
+               PyErr_Print(); /* Returns void. */
                Py_DECREF(py_res);
                Py_DECREF(py_args);
                Py_DECREF(py_func);