Fix: Throw a FieldError exception when get_value() fails

[babeltrace.git] / bindings / python / babeltrace.i.in

diff --git a/bindings/python/babeltrace.i.in b/bindings/python/babeltrace.i.in
index 1ea6b5d2bb6e92cc589d1b00381ca6c5d2512693..f3a00f588fde0d4ca267d6c155ef54792770045d 100644 (file)
--- a/bindings/python/babeltrace.i.in
+++ b/bindings/python/babeltrace.i.in
@@ -576,6 +576,8 @@ struct bt_ctf_event *bt_ctf_iter_read_event(struct bt_ctf_iter *iter);
 %rename("_bt_ctf_get_decl_from_def") bt_ctf_get_decl_from_def(
                const struct bt_definition *field);
 %rename("_bt_array_index") bt_array_index(struct definition_array *array, uint64_t i);
+%rename("_bt_sequence_len")  bt_sequence_len(struct definition_sequence *sequence);
+%rename("_bt_sequence_index") bt_sequence_index(struct definition_sequence *sequence, uint64_t i);
 
 const struct bt_definition *bt_ctf_get_top_level_scope(const struct bt_ctf_event *ctf_event,
                enum bt_ctf_scope scope);
@@ -607,6 +609,8 @@ int bt_ctf_field_get_error(void);
 const char *bt_ctf_get_decl_event_name(const struct bt_ctf_event_decl *event);
 const char *bt_ctf_get_decl_field_name(const struct bt_ctf_field_decl *field);
 const struct bt_declaration *bt_ctf_get_decl_from_def(const struct bt_definition *field);
+uint64_t bt_sequence_len(struct definition_sequence *sequence);
+struct bt_definition *bt_sequence_index(struct definition_sequence *sequence, uint64_t i);
 
 %pythoncode%{
 
@@ -628,6 +632,15 @@ class ctf:
                SEQUENCE = 9
                NR_CTF_TYPES = 10
 
+               def get_type_id_name(id):
+                       name = "UNKNOWN"
+                       constants = [attr for attr in dir(ctf.type_id) if not callable(getattr(ctf.type_id, attr)) and not attr.startswith("__")]
+                       for attr in constants:
+                               if getattr(ctf.type_id, attr) == id:
+                                       name = attr
+                                       break
+                       return name
+
        class scope:
                TRACE_PACKET_HEADER = 0
                STREAM_PACKET_CONTEXT = 1
@@ -880,6 +893,12 @@ class ctf:
                        else:
                                return ctx
 
+       class FieldError(Exception):
+               def __init__(self, value):
+                       self.value = value
+
+               def __str__(self):
+                       return repr(self.value)
 
        class Definition(object):
                """Definition class.  Do not instantiate."""
@@ -960,6 +979,27 @@ class ctf:
                                return None
                        return element
 
+               def get_sequence_len(self):
+                       """
+                       Return the len of a sequence or a negative
+                       value on error.
+                       """
+                       seq = _bt_python_get_sequence_from_def(self._d)
+                       return _bt_sequence_len(seq)
+
+               def get_sequence_element_at(self, index):
+                       """
+                       Return the sequence's element at position index,
+                       otherwise return None
+                       """
+                       seq = _bt_python_get_sequence_from_def(self._d)
+                       if seq is not None:
+                               element = ctf.Definition.__new__(ctf.Definition)
+                               element._d = _bt_sequence_index(seq, index)
+                               if element._d is not None:
+                                       return element
+                       return None
+
                def get_uint64(self):
                        """
                        Return the value associated with the field.
@@ -1002,22 +1042,30 @@ class ctf:
                        Return None on error.
                        """
                        id = self.field_type()
+                       value = None
                        if id == ctf.type_id.STRING:
-                               return self.get_str()
-                       if id == ctf.type_id.ARRAY:
-                               array = []
+                               value = self.get_str()
+                       elif id == ctf.type_id.ARRAY:
+                               value = []
                                for i in range(self.get_array_len()):
                                        element = self.get_array_element_at(i)
-                                       array.append(element.get_value())
-                               return array
-                       if id == ctf.type_id.INTEGER:
+                                       value.append(element.get_value())
+                       elif id == ctf.type_id.INTEGER:
                                if self.get_int_signedness() == 0:
-                                       return self.get_uint64()
+                                       value = self.get_uint64()
                                else:
-                                       return self.get_int64()
-                       if id == ctf.type_id.ENUM:
-                               return self.get_enum_str()
-                       return None
+                                       value = self.get_int64()
+                       elif id == ctf.type_id.ENUM:
+                               value = self.get_enum_str()
+                       elif id == ctf.type_id.SEQUENCE:
+                               seq_len = self.get_sequence_len()
+                               value = []
+                               for i in range(seq_len):
+                                       evDef = self.get_sequence_element_at(i)
+                                       value.append(evDef.get_value())
+                       if ctf.field_error():
+                               raise ctf.FieldError("Error occured while accessing field {} of type {}".format(self.field_name(), ctf.type_id.get_type_id_name(self.field_type())))
+                       return value
 
                def get_scope(self):
                        """Return the scope of a field or None on error."""