X-Git-Url: http://git.efficios.com/?p=babeltrace.git;a=blobdiff_plain;f=src%2Fbindings%2Fpython%2Fbt2%2Fbt2%2Fnative_bt_component_class.i;h=b9e91a4af86e83c9864bb89b8fc1998865aeb909;hp=0b679ec8359a646d000e87672babc4b33adb210e;hb=ce4923b0c7a2de36eba95725334d251e9aa08aad;hpb=416379bc0706641778bba7efbebaa5c6027e81b8

diff --git a/src/bindings/python/bt2/bt2/native_bt_component_class.i b/src/bindings/python/bt2/bt2/native_bt_component_class.i
index 0b679ec8..b9e91a4a 100644
--- a/src/bindings/python/bt2/bt2/native_bt_component_class.i
+++ b/src/bindings/python/bt2/bt2/native_bt_component_class.i
@@ -172,12 +172,162 @@ void native_comp_class_dtor(void) {
 	}
 }
 
+static
+void restore_current_thread_error_and_append_exception_chain_recursive(
+		PyObject *py_exc_value,
+		bt_self_component_class *self_component_class,
+		bt_self_component *self_component,
+		bt_self_message_iterator *self_message_iterator,
+		const char *module_name)
+{
+	PyObject *py_exc_cause_value;
+	PyObject *py_exc_type = NULL;
+	PyObject *py_exc_tb = NULL;
+	GString *gstr = NULL;
+
+	/* If this exception has a cause, handle that one first. */
+	py_exc_cause_value = PyException_GetCause(py_exc_value);
+	if (py_exc_cause_value) {
+		restore_current_thread_error_and_append_exception_chain_recursive(
+			py_exc_cause_value, self_component_class,
+			self_component, self_message_iterator, module_name);
+	}
+
+	/*
+	 * If the raised exception is a bt2.Error, restore the wrapped error.
+	 */
+	if (PyErr_GivenExceptionMatches(py_exc_value, py_mod_bt2_exc_error_type)) {
+		PyObject *py_error_swig_ptr;
+		const bt_error *error;
+		int ret;
+
+		/*
+		 * We never raise a bt2.Error with a cause: it should be the
+		 * end of the chain.
+		 */
+		BT_ASSERT(!py_exc_cause_value);
+
+		/*
+		 * We steal the error object from the exception, to move
+		 * it back as the current thread's error.
+		 */
+		py_error_swig_ptr = PyObject_GetAttrString(py_exc_value, "_ptr");
+		BT_ASSERT(py_error_swig_ptr);
+
+		ret = PyObject_SetAttrString(py_exc_value, "_ptr", Py_None);
+		BT_ASSERT(ret == 0);
+
+		ret = SWIG_ConvertPtr(py_error_swig_ptr, (void **) &error,
+			SWIGTYPE_p_bt_error, 0);
+		BT_ASSERT(ret == 0);
+
+		BT_CURRENT_THREAD_MOVE_ERROR_AND_RESET(error);
+
+		Py_DECREF(py_error_swig_ptr);
+	}
+
+	py_exc_type = PyObject_Type(py_exc_value);
+	py_exc_tb = PyException_GetTraceback(py_exc_value);
+
+	gstr = bt_py_common_format_exception(py_exc_type, py_exc_value,
+			py_exc_tb, BT_LOG_OUTPUT_LEVEL, false);
+	if (!gstr) {
+		/* bt_py_common_format_exception has already warned. */
+		goto end;
+	}
+
+	if (self_component_class) {
+		BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_COMPONENT_CLASS(
+			self_component_class, "%s", gstr->str);
+	} else if (self_component) {
+		BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_COMPONENT(
+			self_component, "%s", gstr->str);
+	} else if (self_message_iterator) {
+		BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_MESSAGE_ITERATOR(
+			self_message_iterator, "%s", gstr->str);
+	} else {
+		BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_UNKNOWN(
+			module_name, "%s", gstr->str);
+	}
+
+end:
+	if (gstr) {
+		g_string_free(gstr, TRUE);
+	}
+
+	Py_XDECREF(py_exc_cause_value);
+	Py_XDECREF(py_exc_type);
+	Py_XDECREF(py_exc_tb);
+}
+
+/*
+ * If you have the following code:
+ *
+ * try:
+ *     try:
+ *         something_that_raises_bt2_error()
+ *     except bt2.Error as e1:
+ *         raise ValueError from e1
+ * except ValueError as e2:
+ *     raise TypeError from e2
+ *
+ * We will have the following exception chain:
+ *
+ *     TypeError -> ValueError -> bt2.Error
+ *
+ * Where the TypeError is the current exception (obtained from PyErr_Fetch).
+ *
+ * The bt2.Error contains a `struct bt_error *` that used to be the current
+ * thread's error, at the moment the exception was raised.
+ *
+ * This function gets to the bt2.Error and restores the wrapped
+ * `struct bt_error *` as the current thread's error.
+ *
+ * Then, for each exception in the chain, starting with the oldest one, it adds
+ * an error cause to the current thread's error.
+ */
+static
+void restore_bt_error_and_append_current_exception_chain(
+		bt_self_component_class *self_component_class,
+		bt_self_component *self_component,
+		bt_self_message_iterator *self_message_iterator,
+		const char *module_name)
+{
+	BT_ASSERT(PyErr_Occurred());
+
+	/* Used to access and restore the current exception. */
+	PyObject *py_exc_type;
+	PyObject *py_exc_value;
+	PyObject *py_exc_tb;
+
+	/* Fetch and normalize the Python exception. */
+	PyErr_Fetch(&py_exc_type, &py_exc_value, &py_exc_tb);
+	PyErr_NormalizeException(&py_exc_type, &py_exc_value, &py_exc_tb);
+	BT_ASSERT(py_exc_type);
+	BT_ASSERT(py_exc_value);
+	BT_ASSERT(py_exc_tb);
+
+	/*
+	 * Set the exception's traceback so it's possible to get it using
+	 * PyException_GetTraceback in
+	 * restore_current_thread_error_and_append_exception_chain_recursive.
+	 */
+	PyException_SetTraceback(py_exc_value, py_exc_tb);
+
+	restore_current_thread_error_and_append_exception_chain_recursive(py_exc_value,
+		self_component_class, self_component, self_message_iterator,
+		module_name);
+
+	PyErr_Restore(py_exc_type, py_exc_value, py_exc_tb);
+}
+
 static inline
 void log_exception_and_maybe_append_error(int log_level,
 		bool append_error,
 		bt_self_component_class *self_component_class,
 		bt_self_component *self_component,
-		bt_self_message_iterator *self_message_iterator)
+		bt_self_message_iterator *self_message_iterator,
+		const char *module_name)
 {
 	GString *gstr;
 
@@ -191,19 +341,10 @@ void log_exception_and_maybe_append_error(int log_level,
 	BT_LOG_WRITE(log_level, BT_LOG_TAG, "%s", gstr->str);
 
 	if (append_error) {
-		if (self_component_class) {
-			BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_COMPONENT_CLASS(
-				self_component_class, "%s", gstr->str);
-		} else if (self_component) {
-			BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_COMPONENT(
-				self_component, "%s", gstr->str);
-		} else if (self_message_iterator) {
-			BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_MESSAGE_ITERATOR(
-				self_message_iterator, "%s", gstr->str);
-		} else {
-			BT_CURRENT_THREAD_ERROR_APPEND_CAUSE_FROM_UNKNOWN(
-				"Python", "%s", gstr->str);
-		}
+		restore_bt_error_and_append_current_exception_chain(
+			self_component_class, self_component,
+			self_message_iterator, module_name);
+
 	}
 
 end:
@@ -213,28 +354,32 @@ end:
 }
 
 static inline
-void loge_exception(void)
+void loge_exception(const char *module_name)
 {
-	log_exception_and_maybe_append_error(BT_LOG_ERROR, true, NULL, NULL, NULL);
+	log_exception_and_maybe_append_error(BT_LOG_ERROR, true, NULL, NULL,
+		NULL, module_name);
 }
 
 static
 void loge_exception_message_iterator(
 		bt_self_message_iterator *self_message_iterator)
 {
-	log_exception_and_maybe_append_error(BT_LOG_ERROR, true, NULL, NULL, self_message_iterator);
+	log_exception_and_maybe_append_error(BT_LOG_ERROR, true, NULL, NULL,
+		self_message_iterator, NULL);
 }
 
 static inline
 void logw_exception(void)
 {
-	log_exception_and_maybe_append_error(BT_LOG_WARNING, false, NULL, NULL, NULL);
+	log_exception_and_maybe_append_error(BT_LOG_WARNING, false, NULL, NULL,
+		NULL, NULL);
 }
 
 static inline
 int py_exc_to_status(bt_self_component_class *self_component_class,
 		bt_self_component *self_component,
-		bt_self_message_iterator *self_message_iterator)
+		bt_self_message_iterator *self_message_iterator,
+		const char *module_name)
 {
 	int status = __BT_FUNC_STATUS_OK;
 	PyObject *exc = PyErr_Occurred();
@@ -262,7 +407,7 @@ int py_exc_to_status(bt_self_component_class *self_component_class,
 		/* Unknown exception: convert to general error */
 		log_exception_and_maybe_append_error(BT_LOG_WARNING, true,
 			self_component_class, self_component,
-			self_message_iterator);
+			self_message_iterator, module_name);
 		status = __BT_FUNC_STATUS_ERROR;
 	}
 
@@ -274,20 +419,20 @@ end:
 static
 int py_exc_to_status_component_class(bt_self_component_class *self_component_class)
 {
-	return py_exc_to_status(self_component_class, NULL, NULL);
+	return py_exc_to_status(self_component_class, NULL, NULL, NULL);
 }
 
 static
 int py_exc_to_status_component(bt_self_component *self_component)
 {
-	return py_exc_to_status(NULL, self_component, NULL);
+	return py_exc_to_status(NULL, self_component, NULL, NULL);
 }
 
 static
 int py_exc_to_status_message_iterator(
 		bt_self_message_iterator *self_message_iterator)
 {
-	return py_exc_to_status(NULL, NULL, self_message_iterator);
+	return py_exc_to_status(NULL, NULL, self_message_iterator, NULL);
 }
 
 /* Component class proxy methods (delegate to the attached Python object) */
@@ -519,7 +664,7 @@ component_class_seek_beginning(bt_self_message_iterator *self_message_iterator)
 	py_result = PyObject_CallMethod(py_iter, "_bt_seek_beginning_from_native",
 		NULL);
 	BT_ASSERT(!py_result || py_result == Py_None);
-        status = py_exc_to_status_message_iterator(self_message_iterator);
+	status = py_exc_to_status_message_iterator(self_message_iterator);
 	Py_XDECREF(py_result);
 	return status;
 }