From 30f073d02d0719e1d5d4e61f68122f174dfa284d Mon Sep 17 00:00:00 2001
From: rbock <rbock@eudoxos.de>
Date: Sun, 1 Nov 2015 09:32:47 +0100
Subject: [PATCH] Moved result_field implementation to result_field_base

Much less boiler plate code this way
---
 .../sqlpp11/data_types/boolean/result_field.h | 65 +-------------
 .../data_types/day_point/result_field.h       | 64 +-------------
 .../data_types/floating_point/result_field.h  | 63 +-------------
 .../data_types/integral/result_field.h        | 64 +-------------
 .../sqlpp11/data_types/text/result_field.h    | 81 +++---------------
 .../data_types/time_point/result_field.h      | 65 +-------------
 include/sqlpp11/result_field.h                |  1 +
 include/sqlpp11/result_field_base.h           | 85 ++++++++++++++++---
 8 files changed, 100 insertions(+), 388 deletions(-)

diff --git a/include/sqlpp11/data_types/boolean/result_field.h b/include/sqlpp11/data_types/boolean/result_field.h
index 27810558..3a4862a8 100644
--- a/include/sqlpp11/data_types/boolean/result_field.h
+++ b/include/sqlpp11/data_types/boolean/result_field.h
@@ -28,81 +28,24 @@
 #define SQLPP_BOOLEAN_RESULT_FIELD_H
 
 #include <sqlpp11/basic_expression_operators.h>
-#include <sqlpp11/exception.h>
 #include <sqlpp11/result_field.h>
 #include <sqlpp11/result_field_base.h>
-#include <sqlpp11/type_traits.h>
 #include <sqlpp11/data_types/boolean/data_type.h>
 #include <ostream>
 
 namespace sqlpp
 {
   template <typename Db, typename FieldSpec>
-  struct result_field_t<boolean, Db, FieldSpec> : public result_field_base_t<result_field_t<boolean, Db, FieldSpec>>
+  struct result_field_t<boolean, Db, FieldSpec> : public result_field_base<Db, FieldSpec, signed char>
   {
+#warning : need to get rid of this static assert by removing the boolean parameter from result_field
     static_assert(std::is_same<value_type_of<FieldSpec>, boolean>::value, "field type mismatch");
-    using _cpp_value_type = typename boolean::_cpp_value_type;
-
-    result_field_t() : _is_valid(false), _is_null(true), _value(false)
-    {
-    }
-
-    void _validate()
-    {
-      _is_valid = true;
-    }
-
-    void _invalidate()
-    {
-      _is_valid = false;
-      _is_null = true;
-      _value = 0;
-    }
-
-    bool is_null() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-      return _is_null;
-    }
-
-    bool _is_trivial() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-
-      return value() == false;
-    }
-
-    _cpp_value_type value() const
-    {
-      if (not _is_valid)
-        throw exception("accessing value in non-existing row");
-
-      if (_is_null)
-      {
-        if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
-        {
-          throw exception("accessing value of NULL field");
-        }
-        else
-        {
-          return false;
-        }
-      }
-      return _value;
-    }
 
     template <typename Target>
-    void _bind(Target& target, size_t i)
+    void _bind(Target& target, size_t index)
     {
-      target._bind_boolean_result(i, &_value, &_is_null);
+      target._bind_boolean_result(index, &this->_value, &this->_is_null);
     }
-
-  private:
-    bool _is_valid;
-    bool _is_null;
-    signed char _value;
   };
 
   template <typename Db, typename FieldSpec>
diff --git a/include/sqlpp11/data_types/day_point/result_field.h b/include/sqlpp11/data_types/day_point/result_field.h
index 53970002..8b0710b3 100644
--- a/include/sqlpp11/data_types/day_point/result_field.h
+++ b/include/sqlpp11/data_types/day_point/result_field.h
@@ -28,81 +28,23 @@
 #define SQLPP_DAY_POINT_RESULT_FIELD_H
 
 #include <sqlpp11/basic_expression_operators.h>
-#include <sqlpp11/exception.h>
 #include <sqlpp11/result_field.h>
 #include <sqlpp11/result_field_base.h>
-#include <sqlpp11/type_traits.h>
 #include <sqlpp11/data_types/day_point/data_type.h>
 #include <ostream>
 
 namespace sqlpp
 {
   template <typename Db, typename FieldSpec>
-  struct result_field_t<day_point, Db, FieldSpec> : public result_field_base_t<result_field_t<day_point, Db, FieldSpec>>
+  struct result_field_t<day_point, Db, FieldSpec> : public result_field_base<Db, FieldSpec>
   {
     static_assert(std::is_same<value_type_of<FieldSpec>, day_point>::value, "field type mismatch");
-    using _cpp_value_type = typename sqlpp::day_point::_cpp_value_type;
-
-    result_field_t() : _is_valid(false), _is_null(true), _value{}
-    {
-    }
-
-    void _invalidate()
-    {
-      _is_valid = false;
-      _is_null = true;
-      _value = _cpp_value_type{};
-    }
-
-    void _validate()
-    {
-      _is_valid = true;
-    }
-
-    bool is_null() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-      return _is_null;
-    }
-
-    bool _is_trivial() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-
-      return value() == _cpp_value_type{};
-    }
-
-    _cpp_value_type value() const
-    {
-      if (not _is_valid)
-        throw exception("accessing value in non-existing row");
-
-      if (_is_null)
-      {
-        if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
-        {
-          throw exception("accessing value of NULL field");
-        }
-        else
-        {
-          return _cpp_value_type{};
-        }
-      }
-      return _value;
-    }
 
     template <typename Target>
-    void _bind(Target& target, size_t i)
+    void _bind(Target& target, size_t index)
     {
-      target._bind_date_result(i, &_value, &_is_null);
+      target._bind_date_result(index, &this->_value, &this->_is_null);
     }
-
-  private:
-    bool _is_valid;
-    bool _is_null;
-    _cpp_value_type _value;
   };
 
   template <typename Db, typename FieldSpec>
diff --git a/include/sqlpp11/data_types/floating_point/result_field.h b/include/sqlpp11/data_types/floating_point/result_field.h
index c36754b7..d96f0c23 100644
--- a/include/sqlpp11/data_types/floating_point/result_field.h
+++ b/include/sqlpp11/data_types/floating_point/result_field.h
@@ -38,72 +38,15 @@
 namespace sqlpp
 {
   template <typename Db, typename FieldSpec>
-  struct result_field_t<floating_point, Db, FieldSpec>
-      : public result_field_base_t<result_field_t<floating_point, Db, FieldSpec>>
+  struct result_field_t<floating_point, Db, FieldSpec> : public result_field_base<Db, FieldSpec>
   {
     static_assert(std::is_same<value_type_of<FieldSpec>, floating_point>::value, "field type mismatch");
-    using _cpp_value_type = typename floating_point::_cpp_value_type;
-
-    result_field_t() : _is_valid(false), _is_null(true), _value(0)
-    {
-    }
-
-    void _validate()
-    {
-      _is_valid = true;
-    }
-
-    void _invalidate()
-    {
-      _is_valid = false;
-      _is_null = true;
-      _value = 0;
-    }
-
-    bool is_null() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-      return _is_null;
-    }
-
-    bool _is_trivial() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-
-      return value() == 0;
-    }
-
-    _cpp_value_type value() const
-    {
-      if (not _is_valid)
-        throw exception("accessing value in non-existing row");
-
-      if (_is_null)
-      {
-        if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
-        {
-          throw exception("accessing value of NULL field");
-        }
-        else
-        {
-          return 0;
-        }
-      }
-      return _value;
-    }
 
     template <typename Target>
-    void _bind(Target& target, size_t i)
+    void _bind(Target& target, size_t index)
     {
-      target._bind_floating_point_result(i, &_value, &_is_null);
+      target._bind_floating_point_result(index, &this->_value, &this->_is_null);
     }
-
-  private:
-    bool _is_valid;
-    bool _is_null;
-    _cpp_value_type _value;
   };
 
   template <typename Db, typename FieldSpec>
diff --git a/include/sqlpp11/data_types/integral/result_field.h b/include/sqlpp11/data_types/integral/result_field.h
index 02df24ff..fc9aec5b 100644
--- a/include/sqlpp11/data_types/integral/result_field.h
+++ b/include/sqlpp11/data_types/integral/result_field.h
@@ -28,81 +28,23 @@
 #define SQLPP_INTEGRAL_RESULT_FIELD_H
 
 #include <sqlpp11/basic_expression_operators.h>
-#include <sqlpp11/exception.h>
 #include <sqlpp11/result_field.h>
 #include <sqlpp11/result_field_base.h>
-#include <sqlpp11/type_traits.h>
 #include <sqlpp11/data_types/integral/data_type.h>
 #include <ostream>
 
 namespace sqlpp
 {
   template <typename Db, typename FieldSpec>
-  struct result_field_t<integral, Db, FieldSpec> : public result_field_base_t<result_field_t<integral, Db, FieldSpec>>
+  struct result_field_t<integral, Db, FieldSpec> : public result_field_base<Db, FieldSpec>
   {
     static_assert(std::is_same<value_type_of<FieldSpec>, integral>::value, "field type mismatch");
-    using _cpp_value_type = typename integral::_cpp_value_type;
-
-    result_field_t() : _is_valid(false), _is_null(true), _value(0)
-    {
-    }
-
-    void _invalidate()
-    {
-      _is_valid = false;
-      _is_null = true;
-      _value = 0;
-    }
-
-    void _validate()
-    {
-      _is_valid = true;
-    }
-
-    bool is_null() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-      return _is_null;
-    }
-
-    bool _is_trivial() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-
-      return value() == 0;
-    }
-
-    _cpp_value_type value() const
-    {
-      if (not _is_valid)
-        throw exception("accessing value in non-existing row");
-
-      if (_is_null)
-      {
-        if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
-        {
-          throw exception("accessing value of NULL field");
-        }
-        else
-        {
-          return 0;
-        }
-      }
-      return _value;
-    }
 
     template <typename Target>
-    void _bind(Target& target, size_t i)
+    void _bind(Target& target, size_t index)
     {
-      target._bind_integral_result(i, &_value, &_is_null);
+      target._bind_integral_result(index, &this->_value, &this->_is_null);
     }
-
-  private:
-    bool _is_valid;
-    bool _is_null;
-    _cpp_value_type _value;
   };
 
   template <typename Db, typename FieldSpec>
diff --git a/include/sqlpp11/data_types/text/result_field.h b/include/sqlpp11/data_types/text/result_field.h
index 593bfd21..c49959e2 100644
--- a/include/sqlpp11/data_types/text/result_field.h
+++ b/include/sqlpp11/data_types/text/result_field.h
@@ -28,90 +28,31 @@
 #define SQLPP_TEXT_RESULT_FIELD_H
 
 #include <sqlpp11/basic_expression_operators.h>
-#include <sqlpp11/exception.h>
 #include <sqlpp11/result_field.h>
 #include <sqlpp11/result_field_base.h>
-#include <sqlpp11/type_traits.h>
 #include <sqlpp11/data_types/text/data_type.h>
 #include <ostream>
 
 namespace sqlpp
 {
+  namespace detail
+  {
+  }
+
   template <typename Db, typename FieldSpec>
-  struct result_field_t<text, Db, FieldSpec> : public result_field_base_t<result_field_t<text, Db, FieldSpec>>
+  struct result_field_t<text, Db, FieldSpec> : public result_field_base<Db, FieldSpec>
   {
     static_assert(std::is_same<value_type_of<FieldSpec>, text>::value, "field type mismatch");
-    using _cpp_value_type = typename text::_cpp_value_type;
-
-    result_field_t() : _is_valid(false), _value_ptr(nullptr), _len(0)
-    {
-    }
-
-    void _validate()
-    {
-      _is_valid = true;
-    }
-
-    void _invalidate()
-    {
-      _is_valid = false;
-      _value_ptr = nullptr;
-      _len = 0;
-    }
-
-    bool operator==(const _cpp_value_type& rhs) const
-    {
-      return value() == rhs;
-    }
-    bool operator!=(const _cpp_value_type& rhs) const
-    {
-      return not operator==(rhs);
-    }
-
-    bool is_null() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-      return _value_ptr == nullptr;
-    }
-
-    bool _is_trivial() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-
-      return value() == "";
-    }
-
-    _cpp_value_type value() const
-    {
-      if (not _is_valid)
-        throw exception("accessing value in non-existing row");
-
-      if (not _value_ptr)
-      {
-        if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
-        {
-          throw exception("accessing value of NULL field");
-        }
-        else
-        {
-          return "";
-        }
-      }
-      return std::string(_value_ptr, _value_ptr + _len);
-    }
 
     template <typename Target>
-    void _bind(Target& target, size_t i)
+    void _bind(Target& target, size_t index)
     {
-      target._bind_text_result(i, &_value_ptr, &_len);
+      const char* text{nullptr};
+      size_t len{};
+      target._bind_text_result(index, &text, &len);
+      this->_value = {text, len};
+      this->_is_null = (len == 0);
     }
-
-  private:
-    bool _is_valid;
-    const char* _value_ptr;
-    size_t _len;
   };
 
   template <typename Db, typename FieldSpec>
diff --git a/include/sqlpp11/data_types/time_point/result_field.h b/include/sqlpp11/data_types/time_point/result_field.h
index 1f1f3680..2c5219da 100644
--- a/include/sqlpp11/data_types/time_point/result_field.h
+++ b/include/sqlpp11/data_types/time_point/result_field.h
@@ -28,83 +28,22 @@
 #define SQLPP_TIME_POINT_RESULT_FIELD_H
 
 #include <sqlpp11/basic_expression_operators.h>
-#include <sqlpp11/exception.h>
 #include <sqlpp11/result_field.h>
 #include <sqlpp11/result_field_base.h>
-#include <sqlpp11/type_traits.h>
 #include <sqlpp11/data_types/time_point/data_type.h>
 #include <ostream>
 
 namespace sqlpp
 {
-  // time_point result field
   template <typename Db, typename FieldSpec>
-  struct result_field_t<time_point, Db, FieldSpec>
-      : public result_field_base_t<result_field_t<time_point, Db, FieldSpec>>
+  struct result_field_t<time_point, Db, FieldSpec> : public result_field_base<Db, FieldSpec>
   {
     static_assert(std::is_same<value_type_of<FieldSpec>, time_point>::value, "field type mismatch");
-    using _cpp_value_type = typename time_point::_cpp_value_type;
-
-    result_field_t() : _is_valid(false), _is_null(true), _value{}
-    {
-    }
-
-    void _invalidate()
-    {
-      _is_valid = false;
-      _is_null = true;
-      _value = _cpp_value_type{};
-    }
-
-    void _validate()
-    {
-      _is_valid = true;
-    }
-
-    bool is_null() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-      return _is_null;
-    }
-
-    bool _is_trivial() const
-    {
-      if (not _is_valid)
-        throw exception("accessing is_null in non-existing row");
-
-      return value() == _cpp_value_type{};
-    }
-
-    _cpp_value_type value() const
-    {
-      if (not _is_valid)
-        throw exception("accessing value in non-existing row");
-
-      if (_is_null)
-      {
-        if (enforce_null_result_treatment_t<Db>::value and not null_is_trivial_value_t<FieldSpec>::value)
-        {
-          throw exception("accessing value of NULL field");
-        }
-        else
-        {
-          return _cpp_value_type{};
-        }
-      }
-      return _value;
-    }
-
     template <typename Target>
     void _bind(Target& target, size_t i)
     {
-      target._bind_date_time_result(i, &_value, &_is_null);
+      target._bind_date_time_result(i, &this->_value, &this->_is_null);
     }
-
-  private:
-    bool _is_valid;
-    bool _is_null;
-    _cpp_value_type _value;
   };
 
   template <typename Db, typename FieldSpec>
diff --git a/include/sqlpp11/result_field.h b/include/sqlpp11/result_field.h
index a277078e..27ef54d7 100644
--- a/include/sqlpp11/result_field.h
+++ b/include/sqlpp11/result_field.h
@@ -33,6 +33,7 @@
 
 namespace sqlpp
 {
+#warning : The value type IS in the FieldSpec!
   template <typename ValueType, typename Db, typename FieldSpec>
   struct result_field_t
   {
diff --git a/include/sqlpp11/result_field_base.h b/include/sqlpp11/result_field_base.h
index ed9034ca..6d33ae35 100644
--- a/include/sqlpp11/result_field_base.h
+++ b/include/sqlpp11/result_field_base.h
@@ -31,21 +31,18 @@
 #include <sqlpp11/basic_expression_operators.h>
 #include <sqlpp11/alias_operators.h>
 #include <sqlpp11/result_field.h>
+#include <sqlpp11/exception.h>
+#include <sqlpp11/type_traits.h>
 
 namespace sqlpp
 {
-  template <typename Field>
-  struct result_field_base_t
+  template <typename Db, typename FieldSpec, typename StorageType = typename value_type_of<FieldSpec>::_cpp_value_type>
+  struct result_field_base
   {
-    static_assert(wrong_t<result_field_base_t>::value, "Invalid argument for result_field_base");
-  };
-
-  template <typename ValueType, typename Db, typename FieldSpec>
-  struct result_field_base_t<result_field_t<ValueType, Db, FieldSpec>>
-  {
-    using _derived_t = result_field_t<ValueType, Db, FieldSpec>;
-    using _field_spec_t = FieldSpec;
     using _db_t = Db;
+    using _field_spec_t = FieldSpec;
+    using _cpp_value_type = typename value_type_of<FieldSpec>::_cpp_value_type;
+    using _cpp_storage_type = StorageType;
 
     static constexpr bool _null_is_trivial =
         column_spec_can_be_null_t<_field_spec_t>::value and
@@ -58,10 +55,74 @@ namespace sqlpp
     using _nodes = detail::type_vector<>;
     using _can_be_null = column_spec_can_be_null_t<_field_spec_t>;
 
-    operator cpp_value_type_of<_field_spec_t>() const
+    result_field_base() : _is_valid{false}, _is_null{true}, _value{}
     {
-      return static_cast<const _derived_t&>(*this).value();
     }
+
+    bool operator==(const _cpp_value_type& rhs) const
+    {
+      return value() == rhs;
+    }
+
+    bool operator!=(const _cpp_value_type& rhs) const
+    {
+      return not operator==(rhs);
+    }
+
+    void _validate()
+    {
+      _is_valid = true;
+    }
+
+    void _invalidate()
+    {
+      _is_valid = false;
+      _is_null = true;
+      _value = {};
+    }
+
+    bool is_null() const
+    {
+      if (not _is_valid)
+        throw exception("accessing is_null in non-existing row");
+      return _is_null;
+    }
+
+    bool _is_trivial() const
+    {
+      if (not _is_valid)
+        throw exception("accessing is_null in non-existing row");
+
+      return value() == _cpp_storage_type{};
+    }
+
+    _cpp_value_type value() const
+    {
+      if (not _is_valid)
+        throw exception("accessing value in non-existing row");
+
+      if (_is_null)
+      {
+        if (not _null_is_trivial)
+        {
+          throw exception("accessing value of NULL field");
+        }
+        else
+        {
+          return {};
+        }
+      }
+      return _value;
+    }
+
+    operator _cpp_value_type() const
+    {
+      return value();
+    }
+
+    bool _is_valid;
+    bool _is_null;
+    _cpp_storage_type _value;
   };
 }
 #endif