added date_type_t, time_type_t and timestamp, ensure allocated postgres resources are released, split repository into basic_repository and repository.

backends/postgres/src/postgres_connection.cpp

@@ -86,15 +86,18 @@ utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_co
   PGresult *res = PQexec(conn_, context.sql.c_str());
 
   if (is_result_error(res)) {
-    return utils::failure(make_error(sql::error_code::FETCH_FAILED, res, conn_, "Failed to fetch", context.sql));
+    const auto err = make_error(sql::error_code::FETCH_FAILED, res, conn_, "Failed to fetch", context.sql);
+    PQclear(res);
+    return utils::failure(err);
   }
 
   std::vector<object::attribute> prototype = context.prototype;
 
   const int num_col = PQnfields(res);
   if (prototype.size() != static_cast<size_t>(num_col)) {
-    return utils::failure(make_error(sql::error_code::FETCH_FAILED, res, conn_,
-                                     "Number of received columns doesn't match expected columns.", context.sql));
+    const auto err = make_error(sql::error_code::FETCH_FAILED, res, conn_, "Number of received columns doesn't match expected columns.", context.sql);
+    PQclear(res);
+    return utils::failure(err);
   }
   for (int i = 0; i < num_col; ++i) {
     if (!prototype.at(i).is_null()) {
@@ -127,13 +130,13 @@ utils::result<std::unique_ptr<sql::statement_impl>, utils::error> postgres_conne
   const sql::query_context &context) {
   auto statement_name = generate_statement_name(context);
 
-  const PGresult *result = PQprepare(conn_, statement_name.c_str(), context.sql.c_str(), static_cast<int>(context.bind_vars.size()), nullptr);
+  PGresult *result = PQprepare(conn_, statement_name.c_str(), context.sql.c_str(), static_cast<int>(context.bind_vars.size()), nullptr);
 
   if (is_result_error(result)) {
     return utils::failure(make_error(sql::error_code::PREPARE_FAILED, result, conn_, "Failed to prepare", context.sql));
   }
 
-  std::unique_ptr<sql::statement_impl> s(std::make_unique<postgres_statement>(conn_, statement_name, context));
+  std::unique_ptr<sql::statement_impl> s(std::make_unique<postgres_statement>(conn_, result, statement_name, context));
   return utils::ok(std::move(s));
 }
 
@@ -277,8 +280,11 @@ utils::result<bool, utils::error> postgres_connection::exists(const std::string
 
   const auto result = utils::to<size_t>(PQcmdTuples(res));
   if (!result) {
+    PQclear(res);
     return utils::failure(make_error(sql::error_code::FAILURE, res, conn_, "Failed to convert result value", stmt));
   }
+
+  PQclear(res);
   return utils::ok(*result == 1);
 }