srd: simplified error checking, in preparation for more of it

[libsigrokdecode.git] / util.c

/*
 * This file is part of the sigrok project.
 *
 * Copyright (C) 2010 Uwe Hermann <uwe@hermann-uwe.de>
 * Copyright (C) 2011 Bert Vermeulen <bert@biot.com>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include "sigrokdecode.h" /* First, so we avoid a _POSIX_C_SOURCE warning. */
#include "sigrokdecode-internal.h"
#include "config.h"


/**
 * Get the value of a python object's attribute, returned as a newly
 * allocated char *.
 *
 * @param py_obj The object to probe.
 * @param attr Name of the attribute to retrieve.
 * @param outstr ptr to char * storage to be filled in.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *         The 'outstr' argument points to a malloc()ed string upon success.
 */
int py_attr_as_str(PyObject *py_obj, const char *attr, char **outstr)
{
	PyObject *py_str;
	int ret;

	if (!PyObject_HasAttrString(py_obj, attr)) {
		srd_dbg("object has no attribute '%s'", attr);
		return SRD_ERR_PYTHON;
	}

	if (!(py_str = PyObject_GetAttrString(py_obj, attr))) {
		/* TODO: report exception message/traceback to err/dbg */
		PyErr_Clear();
		return SRD_ERR_PYTHON;
	}

	ret = py_str_as_str(py_str, outstr);
	Py_XDECREF(py_str);

	return ret;
}


/**
 * Get the value of a python unicode string object, returned as a newly
 * allocated char *.
 *
 * @param py_str The unicode string object.
 * @param outstr ptr to char * storage to be filled in.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *         The 'outstr' argument points to a malloc()ed string upon success.
 */
int py_str_as_str(PyObject *py_str, char **outstr)
{
	PyObject *py_encstr;
	int ret;
	char *str;

	py_encstr = NULL;
	str = NULL;
	ret = SRD_OK;

	if (!PyUnicode_Check(py_str)) {
		srd_dbg("not a string object");
		ret = SRD_ERR_PYTHON;
		goto err_out;
	}

	if (!(py_encstr = PyUnicode_AsEncodedString(py_str, "utf-8", NULL))) {
		ret = SRD_ERR_PYTHON;
		goto err_out;
	}
	if (!(str = PyBytes_AS_STRING(py_encstr))) {
		ret = SRD_ERR_PYTHON;
		goto err_out;
	}

	if (!(*outstr = g_strdup(str))) {
		srd_dbg("malloc failed");
		ret = SRD_ERR_MALLOC;
		goto err_out;
	}

err_out:
	if (py_encstr)
		Py_XDECREF(py_encstr);

	if (PyErr_Occurred()) {
		srd_dbg("string conversion failed");
		/* TODO: dump exception to srd_dbg */
		PyErr_Clear();
	}

	return ret;
}


/**
 * Convert a python list of unicode strings to a NULL-terminated UTF8-encoded
 * char * array. The caller must free each string when finished.
 *
 * @param py_strlist The list object.
 * @param outstr ptr to char ** storage to be filled in.
 *
 * @return SRD_OK upon success, a (negative) error code otherwise.
 *         The 'outstr' argument points to a malloc()ed char ** upon success.
 */
int py_strlist_to_char(PyObject *py_strlist, char ***outstr)
{
	PyObject *py_str;
	int list_len, i;
	char **out, *str;

	list_len = PyList_Size(py_strlist);
	if (!(out = g_try_malloc(sizeof(char *) * (list_len + 1))))
		return SRD_ERR_MALLOC;
	for (i = 0; i < list_len; i++) {
		if (!(py_str = PyUnicode_AsEncodedString(
				PyList_GetItem(py_strlist, i), "utf-8", NULL)))
			return SRD_ERR_PYTHON;
		if (!(str = PyBytes_AS_STRING(py_str)))
			return SRD_ERR_PYTHON;
		out[i] = g_strdup(str);
	}
	out[i] = NULL;
	*outstr = out;

	return SRD_OK;
}