From 63b2ca0dbdae190941d60a55c9cff99d4a75a0e1 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Mon, 31 May 2021 13:18:17 +0100
Subject: Initial commit of prepstmt, selects, record sets

This is full of holes, but all the basics are covered.
---
 lib/input/mysqlBindings.h | 178 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 178 insertions(+)
 create mode 100644 lib/input/mysqlBindings.h

(limited to 'lib/input/mysqlBindings.h')

diff --git a/lib/input/mysqlBindings.h b/lib/input/mysqlBindings.h
new file mode 100644
index 0000000..dcb3ebf
--- /dev/null
+++ b/lib/input/mysqlBindings.h
@@ -0,0 +1,178 @@
+#ifndef MYGRATE_INPUT_MYSQLBINDINGS_H
+#define MYGRATE_INPUT_MYSQLBINDINGS_H
+
+#include <dbTypes.h>
+#include <helpers.h>
+#include <initializer_list>
+#include <mysql.h>
+#include <mysql_types.h>
+#include <variant>
+#include <vector>
+
+namespace MyGrate::Input {
+	struct BingingData {
+		explicit BingingData(unsigned long l, my_bool n = 0) : len {l}, null {n} { }
+		unsigned long len;
+		my_bool null;
+	};
+
+	struct Bindings {
+		// NOLINTNEXTLINE(hicpp-explicit-conversions)
+		explicit Bindings(const std::initializer_list<DbValue> & vs)
+		{
+			binds.reserve(vs.size());
+			data.reserve(vs.size());
+			for (const auto & v : vs) {
+				std::visit(*this, v);
+			}
+		}
+		template<std::integral T>
+		void
+		operator()(const T & v)
+		{
+			auto & b = binds.emplace_back();
+			b.buffer_type = MySQL::CType<T>::type;
+			b.buffer = const_cast<T *>(&v);
+			b.is_unsigned = std::unsigned_integral<T>;
+		}
+		template<std::floating_point T>
+		void
+		operator()(const T & v)
+		{
+			auto & b = binds.emplace_back();
+			b.buffer_type = MySQL::CType<T>::type;
+			b.buffer = const_cast<T *>(&v);
+		}
+		template<Viewable T>
+		void
+		operator()(const T & v)
+		{
+			auto & b = binds.emplace_back();
+			b.buffer_type = MySQL::CType<T>::type;
+			b.buffer = const_cast<typename T::value_type *>(v.data());
+			b.length = &data.emplace_back(v.size(), 0).len;
+		}
+		void
+		operator()(const std::nullptr_t &)
+		{
+			auto & b = binds.emplace_back();
+			b.buffer = nullptr;
+			b.is_null = &data.emplace_back(0, 1).null;
+		}
+		template<typename T>
+		void
+		operator()(const T &)
+		{
+			throw std::runtime_error("Not implemented");
+		}
+		std::vector<MYSQL_BIND> binds;
+		std::vector<BingingData> data;
+	};
+
+	class ResultData : public BingingData {
+	public:
+		ResultData() : BingingData {0} { }
+		virtual ~ResultData() = default;
+
+		[[nodiscard]] virtual DbValue getValue() const = 0;
+	};
+
+	template<typename T> class ResultDataT : public ResultData {
+	public:
+		ResultDataT(MYSQL_BIND & b, const MYSQL_FIELD & f)
+		{
+			b.buffer = &buf;
+			b.buffer_length = sizeof(T);
+			b.is_null = &this->null;
+			b.length = &this->len;
+			b.is_unsigned = std::is_unsigned_v<T>;
+			b.buffer_type = f.type;
+		}
+
+		[[nodiscard]] DbValue
+		getValue() const override
+		{
+			return buf;
+		}
+
+	private:
+		T buf {};
+	};
+
+	template<> class ResultDataT<std::string_view> : public ResultData {
+	public:
+		ResultDataT(MYSQL_BIND & b, const MYSQL_FIELD & f) : buf(f.length)
+		{
+			b.buffer_length = buf.size();
+			b.buffer = buf.data();
+			b.is_null = &this->null;
+			b.length = &this->len;
+			b.buffer_type = f.type;
+		}
+
+		[[nodiscard]] DbValue
+		getValue() const override
+		{
+			return std::string_view {buf.data(), this->len};
+		}
+
+	private:
+		std::vector<char> buf;
+	};
+
+	template<> class ResultDataT<Blob> : public ResultData {
+	public:
+		ResultDataT(MYSQL_BIND & b, const MYSQL_FIELD & f) : buf(f.length)
+		{
+			b.buffer_length = buf.size();
+			b.buffer = buf.data();
+			b.is_null = &this->null;
+			b.length = &this->len;
+			b.buffer_type = f.type;
+		}
+
+		[[nodiscard]] DbValue
+		getValue() const override
+		{
+			return Blob {buf.data(), this->len};
+		}
+
+	private:
+		std::vector<std::byte> buf;
+	};
+
+	template<typename Out> class ResultDataTime : public ResultData {
+	public:
+		ResultDataTime(MYSQL_BIND & b, const MYSQL_FIELD & f)
+		{
+			b.buffer_length = sizeof(MYSQL_TIME);
+			b.buffer = &buf;
+			b.is_null = &this->null;
+			b.length = &this->len;
+			b.buffer_type = f.type;
+		}
+
+		[[nodiscard]] DbValue
+		getValue() const override
+		{
+			return Out {*this};
+		}
+
+	private:
+		operator Date() const
+		{
+			return Date(buf.year, buf.month, buf.day);
+		}
+		operator Time() const
+		{
+			return Time(buf.hour, buf.minute, buf.second);
+		}
+		operator DateTime() const
+		{
+			return DateTime(*this, *this);
+		}
+		MYSQL_TIME buf;
+	};
+}
+
+#endif
-- 
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