ENH: Add retrieval and queries to Extern C interface

Summary

See https://gitlab.indiscale.com/caosdb/customers/lfpb/management/-/issues/411. Extends the Extern C interface by retrieving single and multiple entities and executing queries.

Focus

There is a lot of repetitive new code for create, delete, set, and get functions in ccaosdb.cpp. Some aspects of the c++ objects of Entities, Parents, and Propeties had to be changed in order to comply with the C interface, mainly because of memory management.

The most important new parts is that entities, transactions, properties and parents can now be created and deleted via the C interface, and that their properties can be set and gotten.

Test Environment

In principle, unit tests should be sufficient. Check whether you are content with the extent of the tests. Queries and retrievals are checked in the integration tests.

Check List for the Author

Please, prepare your MR for a review. Be sure to write a summary and a focus and create gitlab comments for the reviewer. They should guide the reviewer through the changes, explain your changes and also point out open questions. For further good practices have a look at our review guidelines

• All automated tests pass
• Reference related Issues
• [ ] Up-to-date CHANGELOG.md
• Annotations in code (Gitlab comments)
  • Intent of new code
  • Problems with old code
  • Why this implementation?

Check List for the Reviewer

• I understand the intent of this MR
• All automated tests pass
• [ ] Up-to-date CHANGELOG.md
• The test environment setup works and the intended behavior is reproducible in the test environment
• In-code documentation and comments are up-to-date.
• Check: Are there specifications? Are they satisfied?

For further good practices have a look at our review guidelines.

include/ccaosdb.h

+/*
+ * This file is a part of the CaosDB Project.
+ * Copyright (C) 2021 Timm Fitschen <t.fitschen@indiscale.com>
+ * Copyright (C) 2021 Florian Spreckelsen <f.spreckelsen@indiscale.com>
+ * Copyright (C) 2021 IndiScale GmbH <info@indiscale.com>
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Affero 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
+ * Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public
+ * License along with this program. If not, see
+ * <https://www.gnu.org/licenses/>.
+ *
+ */
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -31,6 +52,12 @@ int caosdb_constants_COMPATIBLE_SERVER_VERSION_PATCH();
  */
 const char *caosdb_constants_COMPATIBLE_SERVER_VERSION_PRE_RELEASE();
 
+/**
+ * Return the status code reserved for errors in clients wrapping this
+ * interface.
+ */
+int caosdb_status_code_OTHER_CLIENT_ERROR();
+
 /**
  * A wrapper of the C++ Connection class.
  *
@@ -40,6 +67,7 @@ const char *caosdb_constants_COMPATIBLE_SERVER_VERSION_PRE_RELEASE();
  */
 typedef struct {
   void *wrapped_connection;
+  bool _deletable = false;
 } caosdb_connection_connection;
 
 /**
@@ -51,6 +79,7 @@ typedef struct {
  */
 typedef struct {
   void *wrapped_connection_configuration;
+  bool _deletable = false;
 } caosdb_connection_connection_configuration;
 
 /**
@@ -70,10 +99,12 @@ typedef struct {
 
 typedef struct {
   void *wrapped_certificate_provider;
+  bool _deletable = false;
 } caosdb_connection_certificate_provider;
 
 typedef struct {
   void *wrapped_authenticator;
+  bool _deletable = false;
 } caosdb_authentication_authenticator;
 
 /**
@@ -242,62 +273,77 @@ int caosdb_connection_connection_manager_get_connection(
 // not sufficient yet.
 typedef struct {
   void *wrapped_transaction;
+  bool _deletable = false;
 } caosdb_transaction_transaction;
 
+/**
+ * Create a transaction on an existing connection.
+ *
+ * This transaction has to be deleted manually by
+ * caosdb_transaction_delete_transaction() later on.
+ */
 int caosdb_connection_connection_create_transaction(
   caosdb_connection_connection *connection,
   caosdb_transaction_transaction *out);
+int caosdb_transaction_delete_transaction(
+  caosdb_transaction_transaction *transaction);
 int caosdb_transaction_transaction_retrieve_by_id(
   caosdb_transaction_transaction *transaction, const char *id);
+int caosdb_transaction_transaction_retrieve_by_ids(
+  caosdb_transaction_transaction *transaction, const char *ids[], int length);
+int caosdb_transaction_transaction_query(
+  caosdb_transaction_transaction *transaction, const char *query);
 int caosdb_transaction_transaction_execute(
   caosdb_transaction_transaction *transaction);
+// TODO(fspreck) execute_asynchronously may be added as a separate
+// function once we actually support asynchronous execution.
 
 typedef struct {
   void *wrapped_result_set;
+  bool _deletable = false;
 } caosdb_transaction_result_set;
 
 int caosdb_transaction_transaction_get_result_set(
   caosdb_transaction_transaction *transaction,
   caosdb_transaction_result_set *out);
 
+int caosdb_transaction_transaction_get_count_result(
+  caosdb_transaction_transaction *transaction, long *out);
+
 typedef struct {
   void *wrapped_entity;
-  char **id;
-  char **role;
-  char **name;
-  char **description;
-  char **datatype;
-  char **unit;
-  char **value;
-  char **version_id;
+  bool _deletable = false;
 } caosdb_entity_entity;
 
-int caosdb_transaction_result_set_get_entity(
-  caosdb_transaction_result_set *result_set, caosdb_entity_entity *entity,
-  int index);
+int caosdb_transaction_result_set_at(caosdb_transaction_result_set *result_set,
+                                     caosdb_entity_entity *entity, int index);
+int caosdb_transaction_result_set_size(
+  caosdb_transaction_result_set *result_set, int *out);
 
 typedef struct {
   void *wrapped_property;
-  char **id;
-  char **name;
-  char **description;
-  char **datatype;
-  char **unit;
-  char **value;
+  bool _deletable = false;
 } caosdb_entity_property;
 typedef struct {
   void *wrapped_parent;
-  char **id;
-  char **name;
-  char **description;
+  bool _deletable = false;
 } caosdb_entity_parent;
 typedef struct {
   void *wrapped_message;
-  int *code;
-  char **description;
+  bool _deletable = false;
 } caosdb_entity_message;
 
-// GETTERS FOR COMPLEX OBJECTS
+// GETTERS FOR EVERYTHING
+int caosdb_entity_entity_get_id(caosdb_entity_entity *entity, char *out);
+int caosdb_entity_entity_get_role(caosdb_entity_entity *entity, char *out);
+int caosdb_entity_entity_get_name(caosdb_entity_entity *entity, char *out);
+int caosdb_entity_entity_get_description(caosdb_entity_entity *entity,
+                                         char *out);
+int caosdb_entity_entity_get_datatype(caosdb_entity_entity *entity, char *out);
+int caosdb_entity_entity_get_unit(caosdb_entity_entity *entity, char *out);
+int caosdb_entity_entity_get_value(caosdb_entity_entity *entity, char *out);
+int caosdb_entity_entity_get_version_id(caosdb_entity_entity *entity,
+                                        char *out);
 int caosdb_entity_entity_get_errors_size(caosdb_entity_entity *entity,
                                          int *out);
 int caosdb_entity_entity_get_error(caosdb_entity_entity *entity,
@@ -318,6 +364,29 @@ int caosdb_entity_entity_get_parents_size(caosdb_entity_entity *entity,
 int caosdb_entity_entity_get_parent(caosdb_entity_entity *entity,
                                     caosdb_entity_parent *out, int index);
 
+int caosdb_entity_property_get_id(caosdb_entity_property *property, char *out);
+int caosdb_entity_property_get_name(caosdb_entity_property *property,
+                                    char *out);
+int caosdb_entity_property_get_description(caosdb_entity_property *property,
+                                           char *out);
+int caosdb_entity_property_get_importance(caosdb_entity_property *property,
+                                          char *out);
+int caosdb_entity_property_get_datatype(caosdb_entity_property *property,
+                                        char *out);
+int caosdb_entity_property_get_unit(caosdb_entity_property *property,
+                                    char *out);
+int caosdb_entity_property_get_value(caosdb_entity_property *property,
+                                     char *out);
+
+int caosdb_entity_parent_get_id(caosdb_entity_parent *parent, char *out);
+int caosdb_entity_parent_get_name(caosdb_entity_parent *parent, char *out);
+int caosdb_entity_parent_get_description(caosdb_entity_parent *parent,
+                                         char *out);
+
+int caosdb_entity_message_get_code(caosdb_entity_message *message, int *out);
+int caosdb_entity_message_get_description(caosdb_entity_message *message,
+                                          char *out);
+
 // CONSTRUCTORS AND DESTRUCTORS
 int caosdb_entity_create_entity(caosdb_entity_entity *out);
 int caosdb_entity_delete_entity(caosdb_entity_entity *out);
@@ -326,11 +395,43 @@ int caosdb_entity_delete_property(caosdb_entity_property *out);
 int caosdb_entity_create_parent(caosdb_entity_parent *out);
 int caosdb_entity_delete_parent(caosdb_entity_parent *out);
 
-// SETTERS FOR COMPLEX OBJECTS
+// SETTERS FOR EVERYTHING THAT MAY BE SET
+int caosdb_entity_entity_set_role(caosdb_entity_entity *entity,
+                                  const char *role);
+int caosdb_entity_entity_set_name(caosdb_entity_entity *entity,
+                                  const char *name);
+int caosdb_entity_entity_set_description(caosdb_entity_entity *entity,
+                                         const char *description);
+int caosdb_entity_entity_set_datatype(caosdb_entity_entity *entity,
+                                      const char *datatype);
+int caosdb_entity_entity_set_unit(caosdb_entity_entity *entity,
+                                  const char *unit);
+int caosdb_entity_entity_set_value(caosdb_entity_entity *entity,
+                                   const char *value);
 int caosdb_entity_entity_append_parent(caosdb_entity_entity *entity,
                                        caosdb_entity_parent *parent);
+int caosdb_entity_entity_remove_parent(caosdb_entity_entity *entity, int index);
 int caosdb_entity_entity_append_property(caosdb_entity_entity *entity,
                                          caosdb_entity_property *property);
+int caosdb_entity_entity_remove_property(caosdb_entity_entity *entity,
+                                         int index);
+
+int caosdb_entity_property_set_id(caosdb_entity_property *property,
+                                  const char *id);
+int caosdb_entity_property_set_name(caosdb_entity_property *property,
+                                    const char *name);
+int caosdb_entity_property_set_datatype(caosdb_entity_property *property,
+                                        const char *datatype);
+int caosdb_entity_property_set_importance(caosdb_entity_property *property,
+                                          const char *importance);
+int caosdb_entity_property_set_unit(caosdb_entity_property *property,
+                                    const char *unit);
+int caosdb_entity_property_set_value(caosdb_entity_property *property,
+                                     const char *value);
+
+int caosdb_entity_parent_set_id(caosdb_entity_parent *parent, const char *id);
+int caosdb_entity_parent_set_name(caosdb_entity_parent *parent,
+                                  const char *name);
 
 #ifdef __cplusplus
 }