py-common: make bt_py_common_format_exception accept an arbitrary exception

[babeltrace.git] / src / py-common / py-common.c

diff --git a/src/py-common/py-common.c b/src/py-common/py-common.c
index 4fea4d27b5475ecfa5c6c28208ef8de3a0d79795..465f35015ce2bdb76daf108f496b9cec17e8d6d0 100644 (file)
--- a/src/py-common/py-common.c
+++ b/src/py-common/py-common.c
@@ -32,11 +32,10 @@
 #include "py-common.h"
 
 BT_HIDDEN
-GString *bt_py_common_format_exception(int log_level)
+GString *bt_py_common_format_exception(PyObject *py_exc_type,
+               PyObject *py_exc_value, PyObject *py_exc_tb,
+               int log_level, bool chain)
 {
-       PyObject *type = NULL;
-       PyObject *value = NULL;
-       PyObject *traceback = NULL;
        PyObject *traceback_module = NULL;
        PyObject *format_exception_func = NULL;
        PyObject *exc_str_list = NULL;
@@ -44,13 +43,6 @@ GString *bt_py_common_format_exception(int log_level)
        const char *format_exc_func_name;
        Py_ssize_t i;
 
-       BT_ASSERT(PyErr_Occurred());
-       PyErr_Fetch(&type, &value, &traceback);
-       BT_ASSERT(type);
-
-       /* Make sure `value` is what we expected: an instance of `type` */
-       PyErr_NormalizeException(&type, &value, &traceback);
-
        /*
         * Import the standard `traceback` module which contains the
         * functions to format an exception.
@@ -62,12 +54,12 @@ GString *bt_py_common_format_exception(int log_level)
        }
 
        /*
-        * `traceback` can be `NULL`, when we fail to call a Python
+        * `py_exc_tb` can be `NULL`, when we fail to call a Python
         * function from native code (there is no Python stack at that
         * point). For example, a function which takes 5 positional
         * arguments, but 8 were given.
         */
-       format_exc_func_name = traceback ? "format_exception" :
+       format_exc_func_name = py_exc_tb ? "format_exception" :
                "format_exception_only";
        format_exception_func = PyObject_GetAttrString(traceback_module,
                format_exc_func_name);
@@ -83,8 +75,13 @@ GString *bt_py_common_format_exception(int log_level)
                goto error;
        }
 
+       /*
+        * If we are calling format_exception_only, `py_exc_tb` is NULL, so the
+        * effective argument list is of length 2.
+        */
        exc_str_list = PyObject_CallFunctionObjArgs(format_exception_func,
-               type, value, traceback, NULL);
+               py_exc_type, py_exc_value, py_exc_tb, Py_None /* limit */,
+               chain ? Py_True : Py_False /* chain */, NULL);
        if (!exc_str_list) {
                if (BT_LOG_ON_ERROR) {
                        BT_LOGE("Failed to call `traceback.%s` function:",
@@ -139,6 +136,30 @@ end:
        Py_XDECREF(format_exception_func);
        Py_XDECREF(traceback_module);
 
+       return msg_buf;
+}
+
+BT_HIDDEN
+GString *bt_py_common_format_current_exception(int log_level)
+{
+       GString *result;
+       PyObject *py_exc_type = NULL;
+       PyObject *py_exc_value = NULL;
+       PyObject *py_exc_tb = NULL;
+
+       BT_ASSERT(PyErr_Occurred());
+       PyErr_Fetch(&py_exc_type, &py_exc_value, &py_exc_tb);
+       BT_ASSERT(py_exc_type);
+
+       /*
+        * Make sure `py_exc_value` is what we expected: an instance of
+        * `py_exc_type`.
+        */
+       PyErr_NormalizeException(&py_exc_type, &py_exc_value, &py_exc_tb);
+
+       result = bt_py_common_format_exception(py_exc_type, py_exc_value,
+               py_exc_tb, log_level, true);
+
        /*
         * We can safely call PyErr_Restore() because we always call
         * PyErr_Fetch(), and having an error indicator is a function's
@@ -146,7 +167,7 @@ end:
         *
         * PyErr_Restore() steals our references.
         */
-       PyErr_Restore(type, value, traceback);
+       PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb);
 
-       return msg_buf;
+       return result;
 }