mirror of
https://github.com/ton-blockchain/ton
synced 2025-03-09 15:40:10 +00:00
394 lines
8.1 KiB
C++
394 lines
8.1 KiB
C++
/*
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This file is part of TON Blockchain Library.
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TON Blockchain Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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TON Blockchain Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with TON Blockchain Library. If not, see <http://www.gnu.org/licenses/>.
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Copyright 2017-2020 Telegram Systems LLP
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*/
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#pragma once
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#include "td/utils/Slice.h"
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#include <atomic>
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#include <memory>
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#include <new>
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#include <type_traits>
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namespace td {
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namespace detail {
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struct SharedSliceHeader {
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explicit SharedSliceHeader(size_t size) : size_{size} {
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}
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void inc() {
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refcnt_.fetch_add(1, std::memory_order_relaxed);
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}
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bool dec() {
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return refcnt_.fetch_sub(1, std::memory_order_acq_rel) == 1;
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}
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bool is_unique() const {
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// NB: race if std::memory_order_relaxed is used
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// reader may see a change by a new writer
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return refcnt_.load(std::memory_order_acquire) == 1;
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}
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size_t size() const {
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return size_;
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}
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private:
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std::atomic<uint64> refcnt_{1};
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size_t size_;
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};
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struct UniqueSliceHeader {
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explicit UniqueSliceHeader(size_t size) : size_{size} {
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}
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void inc() {
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}
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bool dec() {
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return true;
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}
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bool is_unique() const {
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return true;
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}
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size_t size() const {
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return size_;
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}
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private:
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size_t size_;
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};
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template <class HeaderT, bool zero_on_destruct = false>
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class UnsafeSharedSlice {
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public:
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UnsafeSharedSlice() = default;
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UnsafeSharedSlice clone() const {
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if (is_null()) {
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return UnsafeSharedSlice();
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}
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header()->inc();
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return UnsafeSharedSlice(ptr_.get());
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}
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bool is_null() const {
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return !ptr_;
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}
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bool is_unique() const {
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if (is_null()) {
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return true;
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}
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return header()->is_unique();
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}
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MutableSlice as_mutable_slice() {
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if (is_null()) {
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return MutableSlice();
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}
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return MutableSlice(ptr_.get() + sizeof(HeaderT), header()->size());
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}
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Slice as_slice() const {
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if (is_null()) {
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return Slice();
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}
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return Slice(ptr_.get() + sizeof(HeaderT), header()->size());
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}
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size_t size() const {
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if (is_null()) {
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return 0;
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}
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return header()->size();
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}
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static UnsafeSharedSlice create(size_t size) {
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static_assert(std::is_standard_layout<HeaderT>::value, "HeaderT must have statdard layout");
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auto ptr = std::make_unique<char[]>(sizeof(HeaderT) + size);
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auto header_ptr = new (ptr.get()) HeaderT(size);
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CHECK(header_ptr == reinterpret_cast<HeaderT *>(ptr.get()));
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return UnsafeSharedSlice(std::move(ptr));
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}
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static UnsafeSharedSlice create(Slice slice) {
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auto res = create(slice.size());
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res.as_mutable_slice().copy_from(slice);
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return res;
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}
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void clear() {
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ptr_.reset();
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}
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private:
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explicit UnsafeSharedSlice(char *ptr) : ptr_(ptr) {
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}
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explicit UnsafeSharedSlice(std::unique_ptr<char[]> from) : ptr_(from.release()) {
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}
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HeaderT *header() const {
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return reinterpret_cast<HeaderT *>(ptr_.get());
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}
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struct SharedSliceDestructor {
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void operator()(char *ptr) {
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auto header = reinterpret_cast<HeaderT *>(ptr);
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if (header->dec()) {
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if (zero_on_destruct) {
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MutableSlice(ptr, sizeof(HeaderT) + header->size()).fill_zero_secure();
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}
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std::default_delete<char[]>()(ptr);
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}
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}
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};
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std::unique_ptr<char[], SharedSliceDestructor> ptr_;
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};
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} // namespace detail
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class BufferSlice;
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class UniqueSharedSlice;
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class SharedSlice {
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using Impl = detail::UnsafeSharedSlice<detail::SharedSliceHeader>;
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public:
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SharedSlice() = default;
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explicit SharedSlice(Slice slice) : impl_(Impl::create(slice)) {
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}
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explicit SharedSlice(UniqueSharedSlice from);
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SharedSlice(const char *ptr, size_t size) : SharedSlice(Slice(ptr, size)) {
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}
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SharedSlice clone() const {
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return SharedSlice(impl_.clone());
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}
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Slice as_slice() const {
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return impl_.as_slice();
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}
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BufferSlice clone_as_buffer_slice() const;
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operator Slice() const {
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return as_slice();
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}
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// like in std::string
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const char *data() const {
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return as_slice().data();
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}
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char operator[](size_t at) const {
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return as_slice()[at];
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}
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bool empty() const {
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return size() == 0;
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}
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size_t size() const {
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return impl_.size();
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}
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// like in std::string
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size_t length() const {
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return size();
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}
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void clear() {
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impl_.clear();
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}
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private:
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friend class UniqueSharedSlice;
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explicit SharedSlice(Impl impl) : impl_(std::move(impl)) {
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}
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Impl impl_;
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};
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class UniqueSharedSlice {
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using Impl = detail::UnsafeSharedSlice<detail::SharedSliceHeader>;
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public:
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UniqueSharedSlice() = default;
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explicit UniqueSharedSlice(size_t size) : impl_(Impl::create(size)) {
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}
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explicit UniqueSharedSlice(Slice slice) : impl_(Impl::create(slice)) {
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}
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UniqueSharedSlice(const char *ptr, size_t size) : UniqueSharedSlice(Slice(ptr, size)) {
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}
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explicit UniqueSharedSlice(SharedSlice from) : impl_() {
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if (from.impl_.is_unique()) {
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impl_ = std::move(from.impl_);
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} else {
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impl_ = Impl::create(from.as_slice());
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}
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}
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UniqueSharedSlice copy() const {
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return UniqueSharedSlice(as_slice());
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}
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Slice as_slice() const {
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return impl_.as_slice();
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}
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MutableSlice as_mutable_slice() {
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return impl_.as_mutable_slice();
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}
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operator Slice() const {
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return as_slice();
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}
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// like in std::string
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char *data() {
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return as_mutable_slice().data();
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}
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const char *data() const {
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return as_slice().data();
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}
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char operator[](size_t at) const {
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return as_slice()[at];
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}
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bool empty() const {
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return size() == 0;
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}
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size_t size() const {
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return impl_.size();
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}
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// like in std::string
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size_t length() const {
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return size();
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}
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void clear() {
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impl_.clear();
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}
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private:
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friend class SharedSlice;
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explicit UniqueSharedSlice(Impl impl) : impl_(std::move(impl)) {
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}
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Impl impl_;
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};
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inline SharedSlice::SharedSlice(UniqueSharedSlice from) : impl_(std::move(from.impl_)) {
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}
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template <bool zero_on_destruct>
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class UniqueSliceImpl {
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using Impl = detail::UnsafeSharedSlice<detail::UniqueSliceHeader, zero_on_destruct>;
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public:
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UniqueSliceImpl() = default;
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explicit UniqueSliceImpl(size_t size) : impl_(Impl::create(size)) {
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}
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UniqueSliceImpl(size_t size, char c) : impl_(Impl::create(size)) {
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as_mutable_slice().fill(c);
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}
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explicit UniqueSliceImpl(Slice slice) : impl_(Impl::create(slice)) {
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}
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UniqueSliceImpl(const char *ptr, size_t size) : UniqueSliceImpl(Slice(ptr, size)) {
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}
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UniqueSliceImpl copy() const {
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return UniqueSliceImpl(as_slice());
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}
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Slice as_slice() const {
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return impl_.as_slice();
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}
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MutableSlice as_mutable_slice() {
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return impl_.as_mutable_slice();
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}
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operator Slice() const {
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return as_slice();
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}
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// like in std::string
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char *data() {
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return as_mutable_slice().data();
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}
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const char *data() const {
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return as_slice().data();
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}
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char operator[](size_t at) const {
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return as_slice()[at];
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}
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bool empty() const {
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return size() == 0;
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}
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size_t size() const {
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return impl_.size();
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}
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// like in std::string
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size_t length() const {
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return size();
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}
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void clear() {
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impl_.clear();
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}
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private:
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explicit UniqueSliceImpl(Impl impl) : impl_(std::move(impl)) {
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}
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Impl impl_;
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};
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using UniqueSlice = UniqueSliceImpl<false>;
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using SecureString = UniqueSliceImpl<true>;
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inline MutableSlice as_mutable_slice(UniqueSharedSlice &unique_shared_slice) {
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return unique_shared_slice.as_mutable_slice();
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}
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inline MutableSlice as_mutable_slice(UniqueSlice &unique_slice) {
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return unique_slice.as_mutable_slice();
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}
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inline MutableSlice as_mutable_slice(SecureString &secure_string) {
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return secure_string.as_mutable_slice();
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}
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} // namespace td
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