Commit 723d4d3f authored by Yedidya Feldblum's avatar Yedidya Feldblum Committed by Facebook Github Bot

Refactor is_simple_allocator and callers

Summary:
[Folly] Refactor `is_simple_allocator` and callers.

* Swap order of template parameters.
* Do decaying in the callers instead.
* Do a direct invocability test, rather than an indirect test of whether the allocator has a method `destroy` with the expected signature.

Reviewed By: ericniebler

Differential Revision: D6184062

fbshipit-source-id: aec32e6e323b8c6023b94c258ab2bcddd8c53e09
parent 1bdec475
......@@ -17,6 +17,7 @@
#pragma once
#include <folly/Traits.h>
#include <folly/functional/Invoke.h>
#include <cstddef>
#include <cstdlib>
......@@ -24,6 +25,7 @@
#include <limits>
#include <memory>
#include <stdexcept>
#include <type_traits>
#include <utility>
namespace folly {
......@@ -344,25 +346,23 @@ class allocator_delete
}
};
template <typename T, typename Allocator>
class is_simple_allocator {
FOLLY_CREATE_HAS_MEMBER_FN_TRAITS(has_destroy, destroy);
namespace detail {
typedef typename std::remove_const<
typename std::remove_reference<Allocator>::type
>::type allocator;
typedef typename std::remove_reference<T>::type value_type;
typedef value_type* pointer;
FOLLY_CREATE_MEMBER_INVOKE_TRAITS(destroy_invoke_traits, destroy);
public:
constexpr static bool value = !has_destroy<allocator, void(pointer)>::value
&& !has_destroy<allocator, void(void*)>::value;
};
} // namespace detail
template <typename Allocator, typename Value>
using is_simple_allocator =
Negation<detail::destroy_invoke_traits::is_invocable<Allocator, Value*>>;
template <typename T, typename Allocator>
struct as_stl_allocator {
typedef typename std::conditional<
is_simple_allocator<T, Allocator>::value,
is_simple_allocator<
typename std::remove_reference<Allocator>::type,
typename std::remove_reference<T>::type
>::value,
folly::StlAllocator<
typename std::remove_reference<Allocator>::type,
typename std::remove_reference<T>::type
......@@ -373,7 +373,10 @@ struct as_stl_allocator {
template <typename T, typename Allocator>
typename std::enable_if<
is_simple_allocator<T, Allocator>::value,
is_simple_allocator<
typename std::remove_reference<Allocator>::type,
typename std::remove_reference<T>::type
>::value,
folly::StlAllocator<
typename std::remove_reference<Allocator>::type,
typename std::remove_reference<T>::type
......@@ -387,7 +390,10 @@ typename std::enable_if<
template <typename T, typename Allocator>
typename std::enable_if<
!is_simple_allocator<T, Allocator>::value,
!is_simple_allocator<
typename std::remove_reference<Allocator>::type,
typename std::remove_reference<T>::type
>::value,
typename std::remove_reference<Allocator>::type
>::type make_stl_allocator(Allocator&& allocator) {
return std::move(allocator);
......@@ -405,7 +411,10 @@ struct AllocatorUniquePtr {
typedef std::unique_ptr<T,
folly::allocator_delete<
typename std::conditional<
is_simple_allocator<T, Allocator>::value,
is_simple_allocator<
typename std::remove_reference<Allocator>::type,
typename std::remove_reference<T>::type
>::value,
folly::StlAllocator<typename std::remove_reference<Allocator>::type, T>,
typename std::remove_reference<Allocator>::type
>::type
......
......@@ -25,7 +25,7 @@
using namespace folly;
static_assert(
is_simple_allocator<int,SysArena>::value,
is_simple_allocator<SysArena, int>::value,
"SysArena should be a simple allocator"
);
......
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