implemented prepared statement for postgres and sqlite

backends/postgres/include/postgres_connection.hpp

@@ -14,6 +14,8 @@
 
 #include "matador/sql/connection_impl.hpp"
 
+#include <unordered_map>
+
 #include <libpq-fe.h>
 
 namespace matador::backends::postgres {
@@ -27,7 +29,7 @@ public:
   bool is_open() override;
 
   std::unique_ptr<sql::query_result_impl> fetch(const std::string &stmt) override;
-  void prepare(const std::string &stmt) override;
+  std::unique_ptr<sql::statement_impl> prepare(sql::query_context context) override;
 
   size_t execute(const std::string &stmt) override;
 
@@ -35,8 +37,15 @@ public:
 
   bool exists(const std::string &table_name) override;
 
+private:
+  [[nodiscard]] static std::string generate_statement_name(const sql::query_context &query) ;
+
 private:
   PGconn *conn_{nullptr};
+
+  using string_to_int_map = std::unordered_map<std::string, unsigned long>;
+
+  static string_to_int_map statement_name_map_;
 };
 
 }

backends/postgres/include/postgres_parameter_binder.h

@@ -0,0 +1,42 @@
+#ifndef QUERY_POSTGRES_PARAMETER_BINDER_H
+#define QUERY_POSTGRES_PARAMETER_BINDER_H
+
+#include "matador/sql/parameter_binder.hpp"
+
+#include <vector>
+
+namespace matador::backends::postgres {
+
+class postgres_parameter_binder final : public sql::parameter_binder
+{
+public:
+  explicit postgres_parameter_binder(size_t size);
+
+  void bind(size_t pos, char i) override;
+  void bind(size_t pos, short i) override;
+  void bind(size_t pos, int i) override;
+  void bind(size_t pos, long i) override;
+  void bind(size_t pos, long long int i) override;
+  void bind(size_t pos, unsigned char i) override;
+  void bind(size_t pos, unsigned short i) override;
+  void bind(size_t pos, unsigned int i) override;
+  void bind(size_t pos, unsigned long i) override;
+  void bind(size_t pos, unsigned long long int i) override;
+  void bind(size_t pos, bool b) override;
+  void bind(size_t pos, float d) override;
+  void bind(size_t pos, double d) override;
+  void bind(size_t pos, const char *string) override;
+  void bind(size_t pos, const char *string, size_t size) override;
+  void bind(size_t pos, const std::string &string) override;
+  void bind(size_t pos, const std::string &x, size_t size) override;
+
+  const std::vector<const char*>& params() const;
+
+private:
+  std::vector<std::string> strings_;
+  std::vector<const char*> params_;
+};
+
+}
+
+#endif //QUERY_POSTGRES_PARAMETER_BINDER_H

backends/postgres/include/postgres_statement.hpp

@@ -0,0 +1,34 @@
+#ifndef QUERY_POSTGRES_STATEMENT_HPP
+#define QUERY_POSTGRES_STATEMENT_HPP
+
+#include "matador/sql/statement_impl.hpp"
+
+#include "postgres_parameter_binder.h"
+
+#include <libpq-fe.h>
+
+namespace matador::backends::postgres {
+
+class postgres_statement final : public sql::statement_impl
+{
+public:
+  postgres_statement(PGconn *db, PGresult *result, const std::string &name, const sql::query_context &query);
+
+  size_t execute() override;
+  std::unique_ptr<sql::query_result_impl> fetch() override;
+  void reset() override;
+protected:
+  sql::parameter_binder& binder() override;
+
+private:
+  PGconn *db_{nullptr};
+  PGresult *result_{nullptr};
+
+  std::string name_;
+
+  postgres_parameter_binder binder_;
+};
+
+}
+
+#endif //QUERY_POSTGRES_STATEMENT_HPP