fixup! ircd::db: Various improvements to DB subsystem.

include/ircd/db/value.h

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2016 Charybdis Development Team
+ * Copyright (C) 2016 Jason Volk <jason@zemos.net>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice is present in all copies.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#pragma once
+#define HAVE_IRCD_DB_VALUE_H
+
+namespace ircd {
+namespace db   {
+
+template<database *const &d,
+         class T = string_view>
+struct value
+{
+};
+
+template<database *const &d>
+struct value<d, void>
+:cell
+{
+	using cell::cell;
+
+	value(const string_view &name,
+	      const string_view &index)
+	:cell{*d, name, index}
+	{}
+};
+
+template<database *const &d>
+struct value<d, string_view>
+:value<d, void>
+{
+	operator string_view() const
+	{
+		return string_view{static_cast<const cell &>(*this)};
+	}
+
+	operator string_view()
+	{
+		return string_view{static_cast<cell &>(*this)};
+	}
+
+	using cell::cell;
+
+	value(const string_view &col,
+	      const string_view &row)
+	:value<d, void>{col, row}
+	{}
+
+	value &operator=(const string_view &val)
+	{
+		static_cast<cell &>(*this) = val;
+		return *this;
+	}
+
+	friend std::ostream &operator<<(std::ostream &s, const value<d, string_view> &v)
+	{
+		s << string_view{v};
+		return s;
+	}
+};
+
+template<database *const &d,
+         class T>
+struct arithmetic_value
+:value<d, void>
+{
+	bool compare_exchange(T &expected, const T &desired)
+	{
+		const auto ep(reinterpret_cast<const char *>(&expected));
+		const auto dp(reinterpret_cast<const char *>(&desired));
+
+		string_view s{ep, expected? sizeof(T) : 0};
+		const auto ret(cell::compare_exchange(s, string_view{dp, sizeof(T)}));
+		expected = !s.empty()? *reinterpret_cast<const T *>(s.data()) : 0;
+		return ret;
+	}
+
+	T exchange(const T &desired)
+	{
+		const auto dp(reinterpret_cast<const char *>(&desired));
+		const auto ret(cell::exchange(string_view{dp, desired? sizeof(T) : 0}));
+		return !ret.empty()? *reinterpret_cast<const T *>(ret.data()) : 0;
+	}
+
+	operator T() const
+	{
+		const auto val(this->val());
+		return !val.empty()? *reinterpret_cast<const T *>(val.data()) : 0;
+	}
+
+	operator T()
+	{
+		const auto val(this->val());
+		return !val.empty()? *reinterpret_cast<const T *>(val.data()) : 0;
+	}
+
+	using cell::cell;
+
+	arithmetic_value(const string_view &col,
+	                 const string_view &row)
+	:value<d, void>{col, row}
+	{}
+
+	arithmetic_value &operator=(const T &val)
+	{
+		cell &cell(*this);
+		const auto ptr(reinterpret_cast<const char *>(&val));
+		cell = string_view{ptr, val? sizeof(T) : 0};
+		return *this;
+	}
+
+	friend std::ostream &operator<<(std::ostream &s, const arithmetic_value &v)
+	{
+		s << T(v);
+		return s;
+	}
+};
+
+#define IRCD_ARITHMETIC_VALUE(_type_)                    \
+template<database *const &d>                             \
+struct value<d, _type_>                                  \
+:arithmetic_value<d, _type_>                             \
+{                                                        \
+	using arithmetic_value<d, _type_>::arithmetic_value; \
+}
+
+IRCD_ARITHMETIC_VALUE(uint64_t);
+IRCD_ARITHMETIC_VALUE(int64_t);
+IRCD_ARITHMETIC_VALUE(uint32_t);
+IRCD_ARITHMETIC_VALUE(int32_t);
+IRCD_ARITHMETIC_VALUE(uint16_t);
+IRCD_ARITHMETIC_VALUE(int16_t);
+
+} // namespace db
+} // namespace ircd