moved parameter_binder from member to parameter to bind, execute and fetch methods

backends/postgres/include/postgres_parameter_binder.h

@@ -1,14 +1,13 @@
 #ifndef QUERY_POSTGRES_PARAMETER_BINDER_H
 #define QUERY_POSTGRES_PARAMETER_BINDER_H
 
-#include "matador/utils/attribute_writer.hpp"
+#include "matador/sql/interface/parameter_binder.hpp"
 
 #include <vector>
 
 namespace matador::backends::postgres {
 
-class postgres_parameter_binder final : public utils::attribute_writer
-{
+class postgres_parameter_binder final : public sql::interface::parameter_binder {
 public:
   struct bind_data {
     explicit bind_data(size_t size);

backends/postgres/include/postgres_statement.hpp

@@ -2,8 +2,7 @@
 #define QUERY_POSTGRES_STATEMENT_HPP
 
 #include "matador/sql/interface/statement_impl.hpp"
-
-#include "postgres_parameter_binder.h"
+#include "matador/sql/interface/parameter_binder.hpp"
 
 #include <libpq-fe.h>
 
@@ -14,18 +13,17 @@ class postgres_statement final : public sql::statement_impl
 public:
   postgres_statement(PGconn *db, std::string name, const sql::query_context &query);
 
-  utils::result<size_t, utils::error> execute() override;
-  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch() override;
+  utils::result<size_t, utils::error> execute(const sql::interface::parameter_binder& bindings) override;
+  utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch(const sql::interface::parameter_binder& bindings) override;
   void reset() override;
+
 protected:
-  utils::attribute_writer& binder() override;
+  [[nodiscard]] std::unique_ptr<utils::attribute_writer> create_binder() const override;
 
 private:
   PGconn *db_{nullptr};
 
   std::string name_;
-
-  postgres_parameter_binder binder_;
 };
 
 }

backends/postgres/src/postgres_parameter_binder.cpp

@@ -53,7 +53,7 @@ postgres_parameter_binder::bind_data::bind_data(const size_t size)
 , formats(size)
 {}
 
-postgres_parameter_binder::postgres_parameter_binder(size_t size)
+postgres_parameter_binder::postgres_parameter_binder(const size_t size)
 : bind_data_(size)
 {}
 

backends/postgres/src/postgres_statement.cpp

@@ -1,5 +1,6 @@
 #include "postgres_statement.hpp"
 #include "postgres_error.hpp"
+#include "postgres_parameter_binder.h"
 #include "postgres_result_reader.hpp"
 
 namespace matador::backends::postgres {
@@ -8,17 +9,19 @@ postgres_statement::postgres_statement(PGconn *db, std::string name, const sql::
 : statement_impl(query)
 , db_(db)
 , name_(std::move(name))
-, binder_(query_.bind_vars.size())
 {}
 
-utils::result<size_t, utils::error> postgres_statement::execute()
-{
+utils::result<size_t, utils::error> postgres_statement::execute(const sql::interface::parameter_binder& bindings) {
+  const auto* postgres_bindings = dynamic_cast<const postgres_parameter_binder*>(&bindings);
+  if (!postgres_bindings) {
+    return utils::failure(utils::error(sql::error_code::EXECUTE_FAILED, "Failed to cast bindings to postgres bindings"));
+  }
   PGresult *res = PQexecPrepared(db_,
       name_.c_str(),
-      static_cast<int>(binder_.params().values.size()),
-      binder_.params().values.data(),
-      binder_.params().lengths.data(),
-      binder_.params().formats.data(),
+      static_cast<int>(postgres_bindings->params().values.size()),
+      postgres_bindings->params().values.data(),
+      postgres_bindings->params().lengths.data(),
+      postgres_bindings->params().formats.data(),
       0);
 
   if (is_result_error(res)) {
@@ -30,17 +33,20 @@ utils::result<size_t, utils::error> postgres_statement::execute()
     return utils::ok(static_cast<size_t>(0));
   }
 
-  return utils::ok(static_cast<size_t>(std::stoul(tuples)));
+  return utils::ok((std::stoul(tuples)));
 }
 
-utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_statement::fetch()
-{
+utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_statement::fetch(const sql::interface::parameter_binder& bindings) {
+  const auto* postgres_bindings = dynamic_cast<const postgres_parameter_binder*>(&bindings);
+  if (!postgres_bindings) {
+    return utils::failure(utils::error(sql::error_code::EXECUTE_FAILED, "Failed to cast bindings to postgres bindings"));
+  }
   PGresult *res = PQexecPrepared(db_,
       name_.c_str(),
-      static_cast<int>(binder_.params().values.size()),
-      binder_.params().values.data(),
-      binder_.params().lengths.data(),
-      binder_.params().formats.data(),
+      static_cast<int>(postgres_bindings->params().values.size()),
+      postgres_bindings->params().values.data(),
+      postgres_bindings->params().lengths.data(),
+      postgres_bindings->params().formats.data(),
       0);
 
   if (is_result_error(res)) {
@@ -52,9 +58,7 @@ utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> postgres_st
 
 void postgres_statement::reset() {}
 
-utils::attribute_writer& postgres_statement::binder()
-{
-  return binder_;
+std::unique_ptr<utils::attribute_writer> postgres_statement::create_binder() const {
+  return std::make_unique<postgres_parameter_binder>(query_.bind_vars.size());
+}
 }
-
-}