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Code Issues Releases Wiki Activity

ircd::db: Improve where semantics.

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This commit is contained in:
Jason Volk 2017-09-21 02:09:16 -07:00
parent 15173a1d06
commit 234a34086f
1 changed files with 109 additions and 9 deletions
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118
include/ircd/db/where.h
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@ -31,23 +31,24 @@ namespace ircd::db
template<class tuple>
struct ircd::db::where
{
struct noop;
struct equal;
struct not_equal;
struct logical_not;
struct logical_and;
struct logical_or;
struct test;
struct noop;
virtual bool operator()(const tuple &) const = 0;
virtual ~where() noexcept = default;
};
template<class tuple>
struct ircd::db::where<tuple>::noop
:ircd::db::where<tuple>
namespace ircd::db
{
bool operator()(const tuple &) const override
{
return true;
}
};
template<class T> typename where<T>::logical_or operator||(const where<T> &, const where<T> &);
template<class T> typename where<T>::logical_and operator&&(const where<T> &, const where<T> &);
template<class T> typename where<T>::logical_not operator!(const where<T> &);
}
template<class tuple>
struct ircd::db::where<tuple>::equal
@ -128,3 +129,102 @@ const
return not_equal;
});
}
template<class tuple>
struct ircd::db::where<tuple>::logical_and
:ircd::db::where<tuple>
{
const where *a, *b;
bool operator()(const tuple &t) const override
{
return (*a)(t) && (*b)(t);
}
logical_and(const where &a, const where &b)
:a{&a}
,b{&b}
{}
};
template<class tuple>
typename ircd::db::where<tuple>::logical_and
ircd::db::operator&&(const where<tuple> &a, const where<tuple> &b)
{
return { a, b };
}
template<class tuple>
struct ircd::db::where<tuple>::logical_or
:ircd::db::where<tuple>
{
const where *a, *b;
bool operator()(const tuple &t) const override
{
return (*a)(t) || (*b)(t);
}
logical_or(const where &a, const where &b)
:a{&a}
,b{&b}
{}
};
template<class tuple>
typename ircd::db::where<tuple>::logical_or
ircd::db::operator||(const where<tuple> &a, const where<tuple> &b)
{
return { a, b };
}
template<class tuple>
struct ircd::db::where<tuple>::logical_not
:ircd::db::where<tuple>
{
const where *a;
bool operator()(const tuple &t) const override
{
return !(*a)(t);
}
logical_not(const where &a)
:a{&a}
{}
};
template<class tuple>
typename ircd::db::where<tuple>::logical_not
ircd::db::operator!(const where<tuple> &a)
{
return { a };
}
template<class tuple>
struct ircd::db::where<tuple>::test
:ircd::db::where<tuple>
{
using function = std::function<bool (const tuple &)>;
function closure;
bool operator()(const tuple &t) const override
{
return closure(t);
}
test(function closure)
:closure{std::move(closure)}
{}
};
template<class tuple>
struct ircd::db::where<tuple>::noop
:ircd::db::where<tuple>
{
bool operator()(const tuple &) const override
{
return true;
}
};