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construct/include/ircd/json/tuple/tuple.h
2018-02-05 18:54:55 -08:00

1193 lines
24 KiB
C++

// Matrix Construct
//
// Copyright (C) Matrix Construct Developers, Authors & Contributors
// Copyright (C) 2016-2018 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. The
// full license for this software is available in the LICENSE file.
#pragma once
#define HAVE_IRCD_JSON_TUPLE_H
#include "property.h"
namespace ircd {
namespace json {
/// All tuple templates inherit from this non-template type for tagging.
struct tuple_base
{
// EBO tag
};
/// A compile-time construct to describe a JSON object's members and types.
///
/// Member access by name is O(1) because of recursive constexpr function
/// inlining when translating a name to the index number which is then used
/// as the template argument to std::get() for the value.
///
/// Here we represent a JSON object with a named tuple, allowing the programmer
/// to create a structure specifying all of the potentially valid members of the
/// object. Thus at runtime, the tuple only carries around its values like a
/// `struct`. Unlike a `struct`, the tuple is abstractly iterable and we have
/// implemented logic operating on all JSON tuples regardless of their makeup
/// without any effort from a developer when creating a new tuple.
///
/// The member structure for the tuple is called `property` because json::member
/// is already used to pair together runtime oriented json::values.
///
/// Create and use a tuple to efficiently extract members from a json::object.
/// The tuple will populate its own members during a single-pass iteration of
/// the JSON input.
///
/// But remember, the tuple carries very little information for you at runtime
/// which may make it difficult to represent all JS phenomena like "undefined"
/// and "null".
///
template<class... T>
struct tuple
:std::tuple<T...>
,tuple_base
{
struct keys;
using tuple_type = std::tuple<T...>;
using super_type = tuple<T...>;
static constexpr size_t size();
operator json::value() const;
operator crh::sha256::buf() const;
template<class... U> tuple(const tuple<U...> &);
tuple(const json::object &);
tuple(const json::iov &);
tuple(const std::initializer_list<member> &);
tuple() = default;
};
template<class tuple>
constexpr bool
is_tuple()
{
return std::is_base_of<tuple_base, tuple>::value;
}
template<class tuple,
class R>
using enable_if_tuple = typename std::enable_if<is_tuple<tuple>(), R>::type;
template<class tuple,
class test,
class R>
using enable_if_tuple_and = typename std::enable_if<is_tuple<tuple>() && test(), R>::type;
template<class tuple>
using tuple_type = typename tuple::tuple_type;
template<class tuple>
using tuple_size = std::tuple_size<tuple_type<tuple>>;
template<class tuple,
size_t i>
using tuple_element = typename std::tuple_element<i, tuple_type<tuple>>::type;
template<class tuple,
size_t i>
using tuple_value_type = typename tuple_element<tuple, i>::value_type;
template<class tuple>
auto &
stdcast(const tuple &o)
{
return static_cast<const typename tuple::tuple_type &>(o);
}
template<class tuple>
auto &
stdcast(tuple &o)
{
return static_cast<typename tuple::tuple_type &>(o);
}
template<class tuple>
constexpr enable_if_tuple<tuple, size_t>
size()
{
return tuple_size<tuple>::value;
}
template<class tuple,
size_t i>
constexpr enable_if_tuple<tuple, const char *const &>
key()
{
return tuple_element<tuple, i>::key;
}
template<size_t i,
class tuple>
enable_if_tuple<tuple, const char *const &>
key(const tuple &t)
{
return std::get<i>(t).key;
}
template<class tuple,
size_t hash,
size_t i>
constexpr typename std::enable_if<i == size<tuple>(), size_t>::type
indexof()
{
return size<tuple>();
}
template<class tuple,
size_t hash,
size_t i = 0>
constexpr typename std::enable_if<i < size<tuple>(), size_t>::type
indexof()
{
constexpr auto equal
{
ircd::hash(key<tuple, i>()) == hash
};
return equal? i : indexof<tuple, hash, i + 1>();
}
template<class tuple,
size_t i>
constexpr typename std::enable_if<i == size<tuple>(), size_t>::type
indexof(const char *const &name)
{
return size<tuple>();
}
template<class tuple,
size_t i = 0>
constexpr typename std::enable_if<i < size<tuple>(), size_t>::type
indexof(const char *const &name)
{
constexpr auto equal
{
_constexpr_equal(key<tuple, i>(), name)
};
return equal? i : indexof<tuple, i + 1>(name);
}
template<class tuple,
size_t i>
constexpr typename std::enable_if<i == size<tuple>(), size_t>::type
indexof(const string_view &name)
{
return size<tuple>();
}
template<class tuple,
size_t i = 0>
constexpr typename std::enable_if<i < size<tuple>(), size_t>::type
indexof(const string_view &name)
{
const auto equal
{
name == key<tuple, i>()
};
return equal? i : indexof<tuple, i + 1>(name);
}
template<class tuple>
constexpr bool
key_exists(const string_view &key)
{
return indexof<tuple>(key) < size<tuple>();
}
template<size_t i,
class tuple>
enable_if_tuple<tuple, tuple_value_type<tuple, i> &>
val(tuple &t)
{
return static_cast<tuple_value_type<tuple, i> &>(std::get<i>(t));
}
template<size_t i,
class tuple>
enable_if_tuple<tuple, const tuple_value_type<tuple, i> &>
val(const tuple &t)
{
return static_cast<const tuple_value_type<tuple, i> &>(std::get<i>(t));
}
template<class T>
typename std::enable_if<is_number<T>(), size_t>::type
serialized(T&& t)
{
return lex_cast(t).size();
}
template<class T>
typename std::enable_if<is_number<T>(), bool>::type
defined(T&& t)
{
return !is_zero{}(t);
}
template<class dst,
class src>
typename std::enable_if
<
std::is_base_of<json::string, dst>() &&
std::is_convertible<src, ircd::string_view>(),
void>::type
_assign(dst &d,
src&& s)
{
d = unquote(string_view{std::forward<src>(s)});
}
template<class dst,
class src>
typename std::enable_if
<
!std::is_base_of<json::string, dst>() &&
std::is_convertible<src, dst>() &&
!ircd::json::is_tuple<dst>() &&
!std::is_same<bool, dst>(),
void>::type
_assign(dst &d,
src&& s)
{
d = std::forward<src>(s);
}
template<class dst,
class src>
typename std::enable_if
<
!std::is_base_of<json::string, dst>() &&
std::is_convertible<src, dst>() &&
!ircd::json::is_tuple<dst>() &&
std::is_same<bool, dst>(),
void>::type
_assign(dst &d,
src&& s)
{
static const is_zero test{};
d = test(std::forward<src>(s));
}
template<class dst,
class src>
typename std::enable_if
<
std::is_arithmetic<dst>() &&
std::is_base_of<std::string_view, typename std::remove_reference<src>::type>() &&
!std::is_base_of<ircd::byte_view<ircd::string_view>, typename std::remove_reference<src>::type>(),
void>::type
_assign(dst &d,
src&& s)
try
{
d = lex_cast<dst>(std::forward<src>(s));
}
catch(const bad_lex_cast &e)
{
throw parse_error("cannot convert '%s' to '%s'",
demangle<src>(),
demangle<dst>());
}
template<class dst,
class src>
typename std::enable_if
<
std::is_arithmetic<dst>() &&
std::is_base_of<ircd::byte_view<ircd::string_view>, typename std::remove_reference<src>::type>(),
void>::type
_assign(dst &d,
src&& s)
{
assert(!s.empty());
d = byte_view<dst>(std::forward<src>(s));
}
template<class dst,
class src>
typename std::enable_if
<
std::is_base_of<std::string_view, dst>() &&
std::is_pod<typename std::remove_reference<src>::type>(),
void>::type
_assign(dst &d,
src&& s)
{
d = byte_view<string_view>(std::forward<src>(s));
}
template<class dst,
class src>
typename std::enable_if
<
ircd::json::is_tuple<dst>(),
void>::type
_assign(dst &d,
src&& s)
{
d = dst{std::forward<src>(s)};
}
template<size_t hash,
class tuple>
enable_if_tuple<tuple, const tuple_value_type<tuple, indexof<tuple, hash>()> &>
get(const tuple &t)
{
constexpr size_t idx
{
indexof<tuple, hash>()
};
return val<idx>(t);
}
template<size_t hash,
class tuple>
enable_if_tuple<tuple, tuple_value_type<tuple, indexof<tuple, hash>()>>
get(const tuple &t,
const tuple_value_type<tuple, indexof<tuple, hash>()> &def)
{
constexpr size_t idx
{
indexof<tuple, hash>()
};
const auto &ret
{
val<idx>(t)
};
using value_type = tuple_value_type<tuple, idx>;
//TODO: undefined
return defined(ret)? ret : def;
}
template<size_t hash,
class tuple>
enable_if_tuple<tuple, tuple_value_type<tuple, indexof<tuple, hash>()> &>
get(tuple &t)
{
constexpr size_t idx
{
indexof<tuple, hash>()
};
return val<idx>(t);
}
template<size_t hash,
class tuple>
enable_if_tuple<tuple, tuple_value_type<tuple, indexof<tuple, hash>()> &>
get(tuple &t,
tuple_value_type<tuple, indexof<tuple, hash>()> &def)
{
//TODO: undefined
auto &ret{get<hash, tuple>(t)};
using value_type = decltype(ret);
return defined(ret)? ret : def;
}
template<size_t hash,
class tuple>
enable_if_tuple<tuple, const tuple_value_type<tuple, indexof<tuple, hash>()> &>
at(const tuple &t)
{
constexpr size_t idx
{
indexof<tuple, hash>()
};
auto &ret
{
val<idx>(t)
};
using value_type = tuple_value_type<tuple, idx>;
//TODO: XXX
if(!defined(ret))
throw not_found("%s", key<idx>(t));
return ret;
}
template<size_t hash,
class tuple>
enable_if_tuple<tuple, tuple_value_type<tuple, indexof<tuple, hash>()> &>
at(tuple &t)
{
constexpr size_t idx
{
indexof<tuple, hash>()
};
auto &ret
{
val<idx>(t)
};
using value_type = tuple_value_type<tuple, idx>;
//TODO: XXX
if(!defined(ret))
throw not_found("%s", key<idx>(t));
return ret;
}
template<class tuple,
class function,
size_t i>
typename std::enable_if<i == size<tuple>(), void>::type
at(tuple &t,
const string_view &name,
function&& f)
{
}
template<class tuple,
class function,
size_t i = 0>
typename std::enable_if<i < size<tuple>(), void>::type
at(tuple &t,
const string_view &name,
function&& f)
{
if(indexof<tuple>(name) == i)
f(val<i>(t));
else
at<tuple, function, i + 1>(t, name, std::forward<function>(f));
}
template<class tuple,
class function,
size_t i>
typename std::enable_if<i == size<tuple>(), void>::type
at(const tuple &t,
const string_view &name,
function&& f)
{
}
template<class tuple,
class function,
size_t i = 0>
typename std::enable_if<i < size<tuple>(), void>::type
at(const tuple &t,
const string_view &name,
function&& f)
{
if(indexof<tuple>(name) == i)
f(val<i>(t));
else
at<tuple, function, i + 1>(t, name, std::forward<function>(f));
}
template<size_t i,
class tuple,
class function>
typename std::enable_if<i == size<tuple>(), void>::type
for_each(const tuple &t,
function&& f)
{}
template<size_t i,
class tuple,
class function>
typename std::enable_if<i == size<tuple>(), void>::type
for_each(tuple &t,
function&& f)
{}
template<size_t i = 0,
class tuple,
class function>
typename std::enable_if<i < size<tuple>(), void>::type
for_each(const tuple &t,
function&& f)
{
f(key<i>(t), val<i>(t));
for_each<i + 1>(t, std::forward<function>(f));
}
template<size_t i = 0,
class tuple,
class function>
typename std::enable_if<i < size<tuple>(), void>::type
for_each(tuple &t,
function&& f)
{
f(key<i>(t), val<i>(t));
for_each<i + 1>(t, std::forward<function>(f));
}
template<class tuple,
class function>
void
for_each(const tuple &t,
const vector_view<const string_view> &mask,
function&& f)
{
std::for_each(std::begin(mask), std::end(mask), [&t, &f]
(const auto &key)
{
at(t, key, [&f, &key]
(auto&& val)
{
f(key, val);
});
});
}
template<class tuple,
class function>
void
for_each(tuple &t,
const vector_view<const string_view> &mask,
function&& f)
{
std::for_each(std::begin(mask), std::end(mask), [&t, &f]
(const auto &key)
{
at(t, key, [&f, &key]
(auto&& val)
{
f(key, val);
});
});
}
template<class tuple,
class function,
ssize_t i>
typename std::enable_if<(i < 0), void>::type
rfor_each(const tuple &t,
function&& f)
{}
template<class tuple,
class function,
ssize_t i>
typename std::enable_if<(i < 0), void>::type
rfor_each(tuple &t,
function&& f)
{}
template<class tuple,
class function,
ssize_t i = size<tuple>() - 1>
typename std::enable_if<i < tuple_size<tuple>(), void>::type
rfor_each(const tuple &t,
function&& f)
{
f(key<i>(t), val<i>(t));
rfor_each<tuple, function, i - 1>(t, std::forward<function>(f));
}
template<class tuple,
class function,
ssize_t i = size<tuple>() - 1>
typename std::enable_if<i < tuple_size<tuple>(), void>::type
rfor_each(tuple &t,
function&& f)
{
f(key<i>(t), val<i>(t));
rfor_each<tuple, function, i - 1>(t, std::forward<function>(f));
}
template<size_t i,
class tuple,
class function>
typename std::enable_if<i == size<tuple>(), bool>::type
until(const tuple &t,
function&& f)
{
return true;
}
template<size_t i,
class tuple,
class function>
typename std::enable_if<i == size<tuple>(), bool>::type
until(tuple &t,
function&& f)
{
return true;
}
template<size_t i = 0,
class tuple,
class function>
typename std::enable_if<i < size<tuple>(), bool>::type
until(const tuple &t,
function&& f)
{
return f(key<i>(t), val<i>(t))?
until<i + 1>(t, std::forward<function>(f)):
false;
}
template<size_t i = 0,
class tuple,
class function>
typename std::enable_if<i < size<tuple>(), bool>::type
until(tuple &t,
function&& f)
{
return f(key<i>(t), val<i>(t))?
until<i + 1>(t, std::forward<function>(f)):
false;
}
template<size_t i,
class tuple,
class function>
typename std::enable_if<i == size<tuple>(), bool>::type
until(const tuple &a,
const tuple &b,
function&& f)
{
return true;
}
template<size_t i = 0,
class tuple,
class function>
typename std::enable_if<i < size<tuple>(), bool>::type
until(const tuple &a,
const tuple &b,
function&& f)
{
return f(key<i>(a), val<i>(a), val<i>(b))?
until<i + 1>(a, b, std::forward<function>(f)):
false;
}
template<class tuple,
class function,
ssize_t i>
typename std::enable_if<(i < 0), bool>::type
runtil(const tuple &t,
function&& f)
{
return true;
}
template<class tuple,
class function,
ssize_t i>
typename std::enable_if<(i < 0), bool>::type
runtil(tuple &t,
function&& f)
{
return true;
}
template<class tuple,
class function,
ssize_t i = size<tuple>() - 1>
typename std::enable_if<i < size<tuple>(), bool>::type
runtil(const tuple &t,
function&& f)
{
return f(key<i>(t), val<i>(t))?
runtil<tuple, function, i - 1>(t, std::forward<function>(f)):
false;
}
template<class tuple,
class function,
ssize_t i = size<tuple>() - 1>
typename std::enable_if<i < size<tuple>(), bool>::type
runtil(tuple &t,
function&& f)
{
return f(key<i>(t), val<i>(t))?
runtil<tuple, function, i - 1>(t, std::forward<function>(f)):
false;
}
template<class V,
class... T>
tuple<T...> &
set(tuple<T...> &t,
const string_view &key,
V&& val)
try
{
at(t, key, [&key, &val]
(auto &target)
{
_assign(target, std::forward<V>(val));
});
return t;
}
catch(const std::exception &e)
{
throw parse_error("failed to set member '%s' (from %s): %s",
key,
demangle<V>(),
e.what());
}
template<class... T>
tuple<T...> &
set(tuple<T...> &t,
const string_view &key,
const json::value &value)
{
switch(type(value))
{
case type::STRING:
case type::LITERAL:
set(t, key, string_view{value});
break;
case type::NUMBER:
if(value.floats)
set(t, key, value.floating);
else
set(t, key, value.integer);
break;
case type::OBJECT:
case type::ARRAY:
if(unlikely(!value.serial))
throw print_error("Type %s must be JSON to be used by tuple member '%s'",
reflect(type(value)),
key);
set(t, key, string_view{value});
break;
}
return t;
}
template<class... T>
tuple<T...>::tuple(const json::object &object)
{
std::for_each(std::begin(object), std::end(object), [this]
(const auto &member)
{
set(*this, member.first, member.second);
});
}
template<class... T>
tuple<T...>::tuple(const json::iov &iov)
{
std::for_each(std::begin(iov), std::end(iov), [this]
(const auto &member)
{
set(*this, member.first, member.second);
});
}
template<class... T>
tuple<T...>::tuple(const std::initializer_list<member> &members)
{
std::for_each(std::begin(members), std::end(members), [this]
(const auto &member)
{
set(*this, member.first, member.second);
});
}
template<class... T>
template<class... U>
tuple<T...>::tuple(const tuple<U...> &t)
{
for_each(t, [this]
(const auto &key, const auto &val)
{
set(*this, key, val);
});
}
template<class... T>
constexpr size_t
tuple<T...>::size()
{
return std::tuple_size<tuple_type>();
}
template<class tuple,
class it_a,
class it_b,
class closure>
constexpr auto
_key_transform(it_a it,
const it_b end,
closure&& lambda)
{
for(size_t i(0); i < tuple::size() && it != end; ++i)
{
*it = lambda(key<tuple, i>());
++it;
}
return it;
}
template<class tuple,
class it_a,
class it_b>
constexpr auto
_key_transform(it_a it,
const it_b end)
{
for(size_t i(0); i < tuple::size() && it != end; ++i)
{
*it = key<tuple, i>();
++it;
}
return it;
}
template<class it_a,
class it_b,
class... T>
auto
_key_transform(const tuple<T...> &tuple,
it_a it,
const it_b end)
{
for_each(tuple, [&it, &end]
(const auto &key, const auto &val)
{
if(it != end)
{
*it = key;
++it;
}
});
return it;
}
template<class... T>
struct tuple<T...>::keys
:std::array<string_view, tuple<T...>::size()>
{
struct selection;
struct include;
struct exclude;
constexpr keys()
{
_key_transform<tuple<T...>>(this->begin(), this->end());
}
};
template<class... T>
struct tuple<T...>::keys::selection
:std::bitset<tuple<T...>::size()>
{
template<class closure>
constexpr bool until(closure &&function) const
{
for(size_t i(0); i < this->size(); ++i)
if(this->test(i))
if(!function(key<tuple<T...>, i>()))
return false;
return true;
}
template<class closure>
constexpr void for_each(closure &&function) const
{
this->until([&function](auto&& key)
{
function(key);
return true;
});
}
template<class it_a,
class it_b>
constexpr auto transform(it_a it, const it_b end) const
{
this->until([&it, &end](auto&& key)
{
if(it == end)
return false;
*it = key;
++it;
return true;
});
}
};
template<class... T>
struct tuple<T...>::keys::include
:selection
{
constexpr include(const std::initializer_list<string_view> &list)
{
for(const auto &key : list)
this->set(indexof<tuple<T...>>(key), true);
}
};
template<class... T>
struct tuple<T...>::keys::exclude
:selection
{
constexpr exclude(const std::initializer_list<string_view> &list)
{
this->set();
for(const auto &key : list)
this->set(indexof<tuple<T...>>(key), false);
}
};
template<class it_a,
class it_b,
class closure,
class... T>
auto
_member_transform_if(const tuple<T...> &tuple,
it_a it,
const it_b end,
closure&& lambda)
{
until(tuple, [&it, &end, &lambda]
(const auto &key, const auto &val)
{
if(it == end)
return false;
if(lambda(*it, key, val))
++it;
return true;
});
return it;
}
template<class it_a,
class it_b,
class closure,
class... T>
auto
_member_transform(const tuple<T...> &tuple,
it_a it,
const it_b end,
closure&& lambda)
{
return _member_transform_if(tuple, it, end, [&lambda]
(auto&& ret, const auto &key, const auto &val)
{
ret = lambda(key, val);
return true;
});
}
template<class it_a,
class it_b,
class... T>
auto
_member_transform(const tuple<T...> &tuple,
it_a it,
const it_b end)
{
return _member_transform_if(tuple, it, end, []
(auto&& ret, const auto &key, const auto &val)
{
ret = member { key, val };
return true;
});
}
template<class... T>
size_t
serialized(const tuple<T...> &t)
{
constexpr const size_t member_count
{
tuple<T...>::size()
};
std::array<size_t, member_count> sizes {0};
const auto e{_member_transform_if(t, begin(sizes), end(sizes), []
(auto &ret, const string_view &key, auto&& val)
{
if(!defined(val))
return false;
// " " : ,
ret = 1 + key.size() + 1 + 1 + serialized(val) + 1;
return true;
})};
// Subtract one to get the final size when an extra comma is
// accumulated on non-empty objects.
const auto overhead
{
1 + std::all_of(begin(sizes), e, is_zero{})
};
return std::accumulate(begin(sizes), e, size_t(overhead));
}
template<class... T>
string_view
stringify(mutable_buffer &buf,
const tuple<T...> &tuple)
{
std::array<member, tuple.size()> members;
std::sort(begin(members), end(members), []
(const auto &a, const auto &b)
{
return a.first < b.first;
});
const auto e{_member_transform_if(tuple, begin(members), end(members), []
(auto &ret, const string_view &key, auto&& val)
{
if(!defined(val))
return false;
ret = member { key, val };
return true;
})};
return stringify(buf, begin(members), e);
}
template<class... T>
std::ostream &
operator<<(std::ostream &s, const tuple<T...> &t)
{
s << json::strung(t);
return s;
}
template<class... T>
tuple<T...>::operator
crh::sha256::buf()
const
{
//TODO: XXX
const auto preimage
{
json::strung(*this)
};
return crh::sha256::buf
{
[&preimage](auto &buf)
{
sha256{buf, const_buffer{preimage}};
}
};
}
template<class tuple>
enable_if_tuple<tuple, ed25519::sig>
sign(const tuple &t,
const ed25519::sk &sk)
{
//TODO: XXX
const auto preimage
{
json::strung(t)
};
return ed25519::sig
{
[&sk, &preimage](auto &buf)
{
sk.sign(buf, const_buffer{preimage});
}
};
}
template<class tuple>
enable_if_tuple<tuple, bool>
verify(const tuple &t,
const ed25519::pk &pk,
const ed25519::sig &sig,
std::nothrow_t)
noexcept try
{
//TODO: XXX
const auto preimage
{
json::strung(t)
};
return pk.verify(const_buffer{preimage}, sig);
}
catch(const std::exception &e)
{
log::error("Verification of json::tuple unexpected failure: %s", e.what());
return false;
}
template<class tuple>
enable_if_tuple<tuple, void>
verify(const tuple &t,
const ed25519::pk &pk,
const ed25519::sig &sig)
{
if(!verify(t, pk, sig, std::nothrow))
throw ed25519::bad_sig{"Verification failed"};
}
template<class tuple>
enable_if_tuple<tuple, void>
verify(const tuple &t,
const ed25519::pk &pk)
{
const ed25519::sig sig
{
[&t](auto &buf)
{
b64decode(buf, at<"signatures"_>(t));
}
};
auto copy(t);
at<"signatures"_>(copy) = string_view{};
if(!verify(copy, pk, sig, std::nothrow))
throw ed25519::bad_sig{"Verification failed"};
}
template<class... T>
tuple<T...>::operator
json::value()
const
{
json::value ret;
ret.type = OBJECT;
ret.create_string(serialized(*this), [this]
(mutable_buffer buffer)
{
stringify(buffer, *this);
});
return ret;
}
} // namespace json
} // namespace ircd