tvl-depot/absl/container/internal/common.h
Abseil Team b69c7d880c Export of internal Abseil changes
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00f5301405423005d9129935c05f20155536cc1a by CJ Johnson <johnsoncj@google.com>:

Removes usage of std::aligned_storage from Abseil implementation details

PiperOrigin-RevId: 296492301

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fc11d15f91764612fba080669d2381dc181df52b by Abseil Team <absl-team@google.com>:

Fix absl::bind_front documentation.

PiperOrigin-RevId: 296482945

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0164c595c129c46bf21ae74eba5399a1da5f140b by Gennadiy Rozental <rogeeff@google.com>:

Automated g4 rollback of changelist 296320700.

PiperOrigin-RevId: 296439968

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1eb295700758ca0894d872b2de7c675b4ad679af by Abseil Team <absl-team@google.com>:

Removes duplicate comments.

PiperOrigin-RevId: 296433214

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c30c01caae02d2fa4ef783d988de6bebb9757c39 by Derek Mauro <dmauro@google.com>:

Merge GitHub #621: Add RISCV support to GetProgramCounter()

Fixes #621

PiperOrigin-RevId: 296351174

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95d4498167596fd7543e025bdfe9a8da9e2ca3c8 by Abseil Team <absl-team@google.com>:

Automated g4 rollback of changelist 296320700.

PiperOrigin-RevId: 296348701

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b193f0543e0cec54dddb2ed51f45dc489c8d06d5 by Gennadiy Rozental <rogeeff@google.com>:

Change TryParse interface to return managed value.

In addition introduce companion StoreValue routine which consumes pointer to source value and stores the value inside of FlagImpl. In a follow up CL we will change StoreValue implementation to behave differently depending on "value storage kind".
We also rename default_src_ to default_value_.

PiperOrigin-RevId: 296320700

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57e942b485d12912a0a8d0d0b35fa2a62847020f by Derek Mauro <dmauro@google.com>:

Merge GitHub #622
 * Add missing #ifdef conditionals for ABSL_HAVE_VDSO_SUPPORT

PiperOrigin-RevId: 296272830
GitOrigin-RevId: 00f5301405423005d9129935c05f20155536cc1a
Change-Id: I1b05eeaf1280f95fb0a2c5f3654995a87c792893
2020-02-21 15:56:04 -05:00

202 lines
5.2 KiB
C++

// Copyright 2018 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#ifndef ABSL_CONTAINER_INTERNAL_CONTAINER_H_
#define ABSL_CONTAINER_INTERNAL_CONTAINER_H_
#include <cassert>
#include <type_traits>
#include "absl/meta/type_traits.h"
#include "absl/types/optional.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace container_internal {
template <class, class = void>
struct IsTransparent : std::false_type {};
template <class T>
struct IsTransparent<T, absl::void_t<typename T::is_transparent>>
: std::true_type {};
template <bool is_transparent>
struct KeyArg {
// Transparent. Forward `K`.
template <typename K, typename key_type>
using type = K;
};
template <>
struct KeyArg<false> {
// Not transparent. Always use `key_type`.
template <typename K, typename key_type>
using type = key_type;
};
// The node_handle concept from C++17.
// We specialize node_handle for sets and maps. node_handle_base holds the
// common API of both.
template <typename PolicyTraits, typename Alloc>
class node_handle_base {
protected:
using slot_type = typename PolicyTraits::slot_type;
public:
using allocator_type = Alloc;
constexpr node_handle_base() = default;
node_handle_base(node_handle_base&& other) noexcept {
*this = std::move(other);
}
~node_handle_base() { destroy(); }
node_handle_base& operator=(node_handle_base&& other) noexcept {
destroy();
if (!other.empty()) {
alloc_ = other.alloc_;
PolicyTraits::transfer(alloc(), slot(), other.slot());
other.reset();
}
return *this;
}
bool empty() const noexcept { return !alloc_; }
explicit operator bool() const noexcept { return !empty(); }
allocator_type get_allocator() const { return *alloc_; }
protected:
friend struct CommonAccess;
struct transfer_tag_t {};
node_handle_base(transfer_tag_t, const allocator_type& a, slot_type* s)
: alloc_(a) {
PolicyTraits::transfer(alloc(), slot(), s);
}
struct move_tag_t {};
node_handle_base(move_tag_t, const allocator_type& a, slot_type* s)
: alloc_(a) {
PolicyTraits::construct(alloc(), slot(), s);
}
void destroy() {
if (!empty()) {
PolicyTraits::destroy(alloc(), slot());
reset();
}
}
void reset() {
assert(alloc_.has_value());
alloc_ = absl::nullopt;
}
slot_type* slot() const {
assert(!empty());
return reinterpret_cast<slot_type*>(std::addressof(slot_space_));
}
allocator_type* alloc() { return std::addressof(*alloc_); }
private:
absl::optional<allocator_type> alloc_ = {};
alignas(slot_type) mutable unsigned char slot_space_[sizeof(slot_type)] = {};
};
// For sets.
template <typename Policy, typename PolicyTraits, typename Alloc,
typename = void>
class node_handle : public node_handle_base<PolicyTraits, Alloc> {
using Base = node_handle_base<PolicyTraits, Alloc>;
public:
using value_type = typename PolicyTraits::value_type;
constexpr node_handle() {}
value_type& value() const { return PolicyTraits::element(this->slot()); }
private:
friend struct CommonAccess;
using Base::Base;
};
// For maps.
template <typename Policy, typename PolicyTraits, typename Alloc>
class node_handle<Policy, PolicyTraits, Alloc,
absl::void_t<typename Policy::mapped_type>>
: public node_handle_base<PolicyTraits, Alloc> {
using Base = node_handle_base<PolicyTraits, Alloc>;
public:
using key_type = typename Policy::key_type;
using mapped_type = typename Policy::mapped_type;
constexpr node_handle() {}
auto key() const -> decltype(PolicyTraits::key(this->slot())) {
return PolicyTraits::key(this->slot());
}
mapped_type& mapped() const {
return PolicyTraits::value(&PolicyTraits::element(this->slot()));
}
private:
friend struct CommonAccess;
using Base::Base;
};
// Provide access to non-public node-handle functions.
struct CommonAccess {
template <typename Node>
static auto GetSlot(const Node& node) -> decltype(node.slot()) {
return node.slot();
}
template <typename Node>
static void Destroy(Node* node) {
node->destroy();
}
template <typename Node>
static void Reset(Node* node) {
node->reset();
}
template <typename T, typename... Args>
static T Transfer(Args&&... args) {
return T(typename T::transfer_tag_t{}, std::forward<Args>(args)...);
}
template <typename T, typename... Args>
static T Move(Args&&... args) {
return T(typename T::move_tag_t{}, std::forward<Args>(args)...);
}
};
// Implement the insert_return_type<> concept of C++17.
template <class Iterator, class NodeType>
struct InsertReturnType {
Iterator position;
bool inserted;
NodeType node;
};
} // namespace container_internal
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_CONTAINER_INTERNAL_CONTAINER_H_