Add support for structure fields in the Python bindings

get_value() returns a dictionary when the field is a structure.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/bindings/python/babeltrace.i.in b/bindings/python/babeltrace.i.in
index c39b53ad08866b06fbd9811aac74e3c0e7b6e750..725940c96ca8f9691f94c61abdd49483c79cba96 100644 (file)
--- a/bindings/python/babeltrace.i.in
+++ b/bindings/python/babeltrace.i.in
@@ -580,6 +580,8 @@ struct bt_ctf_event *bt_ctf_iter_read_event(struct bt_ctf_iter *iter);
 %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);
+%rename("_bt_ctf_get_struct_field_count") bt_ctf_get_struct_field_count(const struct bt_definition *structure);
+%rename("_bt_ctf_get_struct_field_index") bt_ctf_get_struct_field_index(const struct bt_definition *structure, 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);
@@ -615,6 +617,8 @@ 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);
+uint64_t bt_ctf_get_struct_field_count(const struct bt_definition *structure);
+const struct bt_definition *bt_ctf_get_struct_field_index(const struct bt_definition *structure, uint64_t i);
 
 %pythoncode%{
 
@@ -1058,6 +1062,23 @@ class ctf:
                        """
                        return _bt_ctf_get_variant(self._d)
 
+               def get_struct_field_count(self):
+                       """
+                       Return the number of fields contained in the structure.
+                       If the field does not exist or is not of the type requested,
+                       the value returned is undefined.
+                       """
+                       return _bt_ctf_get_struct_field_count(self._d)
+
+               def get_struct_field_at(self, i):
+                       """
+                       Return the structure's field at position i.
+                       If the field does not exist or is not of the type requested,
+                       the value returned is undefined. To check if an error occured,
+                       use the ctf.field_error() function after accessing a field.
+                       """
+                       return _bt_ctf_get_struct_field_index(self._d, i)
+
                def get_value(self):
                        """
                        Return the value associated with the field according to its type.
@@ -1091,6 +1112,12 @@ class ctf:
                                variant = ctf.Definition.__new__(ctf.Definition)
                                variant._d = self.get_variant();
                                value = variant.get_value()
+                       elif id == ctf.type_id.STRUCT:
+                               value = {}
+                               for i in range(self.get_struct_field_count()):
+                                       member = ctf.Definition.__new__(ctf.Definition)
+                                       member._d = self.get_struct_field_at(i);
+                                       value[member.field_name()] = member.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())))

diff --git a/formats/ctf/events.c b/formats/ctf/events.c
index f38278aadc6d64ebd4be1f5d9165bf31b313f339..8174293b28e85b80b2038ecec808c3490488636f 100644 (file)
--- a/formats/ctf/events.c
+++ b/formats/ctf/events.c
@@ -637,6 +637,18 @@ const struct bt_definition *bt_ctf_get_variant(const struct bt_definition *field
 
        return ret;
 }
+
+uint64_t bt_ctf_get_struct_field_count(const struct bt_definition *field)
+{
+       uint64_t ret = -1;
+       const struct bt_declaration *declaration =
+               bt_ctf_get_decl_from_def(field);
+
+       if (field && bt_ctf_field_type(declaration) == CTF_TYPE_STRUCT) {
+               const struct declaration_struct *struct_declaration =
+                       container_of(declaration, struct declaration_struct, p);
+
+               ret = bt_struct_declaration_len(struct_declaration);
        } else {
                bt_ctf_field_set_error(-EINVAL);
        }
@@ -644,6 +656,27 @@ const struct bt_definition *bt_ctf_get_variant(const struct bt_definition *field
        return ret;
 }
 
+const struct bt_definition *bt_ctf_get_struct_field_index(
+               const struct bt_definition *field, uint64_t i)
+{
+       const struct bt_definition *ret = NULL;
+
+       if (field && bt_ctf_field_type(
+               bt_ctf_get_decl_from_def(field)) == CTF_TYPE_STRUCT &&
+               i < bt_ctf_get_struct_field_count(field)) {
+               const struct definition_struct *structure = container_of(
+                       field, struct definition_struct, p);
+
+               ret = bt_struct_definition_get_field_from_index(structure, i);
+       }
+
+       if (!ret) {
+               bt_ctf_field_set_error(-EINVAL);
+       }
+
+       return ret;
+}
+
 int bt_ctf_get_event_decl_list(int handle_id, struct bt_context *ctx,
                struct bt_ctf_event_decl * const **list,
                unsigned int *count)

diff --git a/include/babeltrace/ctf/events.h b/include/babeltrace/ctf/events.h
index 414716d2c079b631936e19330fd82846c810a45e..c81d8852f83207881524129b1186d7a946c7f225 100644 (file)
--- a/include/babeltrace/ctf/events.h
+++ b/include/babeltrace/ctf/events.h
@@ -211,6 +211,12 @@ enum ctf_string_encoding bt_ctf_get_encoding(const struct bt_declaration *decl);
  */
 int bt_ctf_get_array_len(const struct bt_declaration *decl);
 
+/*
+ * bt_ctf_get_struct_field_count: return the number of fields in a structure.
+ * Returns a negative value on error.
+ */
+uint64_t bt_ctf_get_struct_field_count(const struct bt_definition *field);
+
 /*
  * Field access functions
  *
@@ -233,6 +239,8 @@ char *bt_ctf_get_char_array(const struct bt_definition *field);
 char *bt_ctf_get_string(const struct bt_definition *field);
 double bt_ctf_get_float(const struct bt_definition *field);
 const struct bt_definition *bt_ctf_get_variant(const struct bt_definition *field);
+const struct bt_definition *bt_ctf_get_struct_field_index(
+               const struct bt_definition *field, uint64_t i);
 
 /*
  * bt_ctf_field_get_error: returns the last error code encountered while

diff --git a/include/babeltrace/types.h b/include/babeltrace/types.h
index 438e79f3cff805fe535e564a78c52b5ab458a82f..677818b9417b7309ec634e956dfab1f617fad394 100644 (file)
--- a/include/babeltrace/types.h
+++ b/include/babeltrace/types.h
@@ -457,10 +457,10 @@ struct declaration_field *
 bt_struct_declaration_get_field_from_index(struct declaration_struct *struct_declaration,
                                        int index);
 struct bt_definition *
-bt_struct_definition_get_field_from_index(struct definition_struct *struct_definition,
+bt_struct_definition_get_field_from_index(const struct definition_struct *struct_definition,
                                       int index);
 int bt_struct_rw(struct bt_stream_pos *pos, struct bt_definition *definition);
-uint64_t bt_struct_declaration_len(struct declaration_struct *struct_declaration);
+uint64_t bt_struct_declaration_len(const struct declaration_struct *struct_declaration);
 
 /*
  * The tag enumeration is validated to ensure that it contains only mappings

diff --git a/types/struct.c b/types/struct.c
index b9fb6799b938dad37f6788c5bb14cafda8fa571d..7eaa42426054b9a617c551da6fcc38006bcee7e7 100644 (file)
--- a/types/struct.c
+++ b/types/struct.c
@@ -242,7 +242,7 @@ struct declaration_field *
  * field returned only valid as long as the field structure is not appended to.
  */
 struct bt_definition *
-bt_struct_definition_get_field_from_index(struct definition_struct *_struct,
+bt_struct_definition_get_field_from_index(const struct definition_struct *_struct,
                                        int index)
 {
        if (index < 0)
@@ -250,7 +250,7 @@ bt_struct_definition_get_field_from_index(struct definition_struct *_struct,
        return g_ptr_array_index(_struct->fields, index);
 }
 
-uint64_t bt_struct_declaration_len(struct declaration_struct *struct_declaration)
+uint64_t bt_struct_declaration_len(const struct declaration_struct *struct_declaration)
 {
        return struct_declaration->fields->len;
 }