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// Copyright (c) 2023 Klemens D. Morgenstern
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_SQLITE_DETAIL_AGGREGATE_FUNCTION_HPP
#define BOOST_SQLITE_DETAIL_AGGREGATE_FUNCTION_HPP
#include <boost/sqlite/detail/config.hpp>
#include <boost/sqlite/detail/catch.hpp>
#include <boost/sqlite/error.hpp>
#include <boost/sqlite/cstring_ref.hpp>
#include <boost/sqlite/memory.hpp>
#include <boost/sqlite/result.hpp>
#include <boost/sqlite/value.hpp>
#include <boost/callable_traits/args.hpp>
#include <boost/callable_traits/return_type.hpp>
#include <boost/callable_traits/has_void_return.hpp>
#include <boost/core/span.hpp>
BOOST_SQLITE_BEGIN_NAMESPACE
namespace detail
{
template<typename Func>
struct aggregate_function_maker
{
void * mem;
template<typename ... Args>
Func* operator()(Args && ... args)
{
return new (mem) Func(std::forward<Args>(args)...);
}
};
template<typename Func, typename Args>
int create_aggregate_function(sqlite3 * db, cstring_ref name, Args && args, int flags,
std::true_type /* void return */)
{
using args_type = callable_traits::args_t<decltype(&Func::step)>;
using span_type = typename std::tuple_element<1U, args_type>::type;
using func_type = typename std::decay<Func>::type;
using func_args_type = typename std::decay<Args>::type;
return sqlite3_create_function_v2(
db, name.c_str(),
span_type::extent == boost::dynamic_extent ? -1 : static_cast<int>(span_type::extent),
SQLITE_UTF8 | flags,
new (memory_tag{}) func_args_type(std::forward<Args>(args)),
nullptr,
+[](sqlite3_context* ctx, int len, sqlite3_value** args)
{
auto aa = reinterpret_cast<value*>(args);
auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
execute_context_function(
ctx,
[&]() -> result<void>
{
if (c == nullptr)
{
auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
if (!p)
return error(SQLITE_NOMEM);
c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
}
c->step(span_type{aa, static_cast<std::size_t>(len)});
return {};
});
},
[](sqlite3_context* ctx)
{
auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
execute_context_function(
ctx,
[&]() -> result<decltype(c->final())>
{
if (c == nullptr)
{
auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
if (!p)
return error(SQLITE_NOMEM);
c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
}
struct reaper {void operator()(func_type * c) { c->~func_type();}};
std::unique_ptr<func_type, reaper> cl{c};
return c->final();
});
},
[](void * ptr) noexcept { delete_(static_cast<func_type*>(ptr));}
);
}
template<typename Func, typename Args>
int create_aggregate_function(sqlite3 * db, cstring_ref name, Args && args, int flags,
std::false_type /* void return */)
{
using args_type = callable_traits::args_t<decltype(&Func::step)>;
using span_type = typename std::tuple_element<1U, args_type>::type;
using func_type = typename std::decay<Func>::type;
using func_args_type = typename std::decay<Args>::type;
return sqlite3_create_function_v2(
db, name.c_str(),
span_type::extent == boost::dynamic_extent ? -1 : static_cast<int>(span_type::extent),
SQLITE_UTF8 | flags,
new (memory_tag{}) func_args_type(std::forward<Args>(args)),
nullptr,
+[](sqlite3_context* ctx, int len, sqlite3_value** args)
{
auto aa = reinterpret_cast<value*>(args);
auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
execute_context_function(
ctx,
[&]() -> result<void>
{
if (c == nullptr)
{
auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
if (!p)
return {system::in_place_error, error(SQLITE_NOMEM)};
c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
}
return c->step(span_type{aa, static_cast<std::size_t>(len)});
});
},
[](sqlite3_context* ctx)
{
auto fa = reinterpret_cast<func_args_type*>(sqlite3_user_data(ctx));
auto c = static_cast<func_type*>(sqlite3_aggregate_context(ctx, 0));
execute_context_function(
ctx,
[&]() -> result<decltype(c->final())>
{
if (c == nullptr)
{
auto p = sqlite3_aggregate_context(ctx, sizeof(func_type));
if (!p)
return {system::in_place_error, error(SQLITE_NOMEM)};
c = mp11::tuple_apply(aggregate_function_maker<func_type>{p}, *fa);
}
struct reaper {void operator()(func_type * c) { c->~func_type();}};
std::unique_ptr<func_type, reaper> cl{c};
return c->final();
});
},
[](void * ptr) noexcept { delete_(static_cast<func_type*>(ptr));}
);
}
}
BOOST_SQLITE_END_NAMESPACE
#endif //BOOST_SQLITE_DETAIL_AGGREGATE_FUNCTION_HPP
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