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tdutils/td/utils/SharedObjectPool.h

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+/*
+    This file is part of TON Blockchain Library.
+
+    TON Blockchain Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    TON Blockchain Library is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with TON Blockchain Library.  If not, see <http://www.gnu.org/licenses/>.
+
+    Copyright 2017-2019 Telegram Systems LLP
+*/
+#pragma once
+
+#include "td/utils/common.h"
+#include "td/utils/logging.h"
+#include "td/utils/MpscLinkQueue.h"
+
+#include <atomic>
+#include <memory>
+#include <new>
+#include <utility>
+
+namespace td {
+
+namespace detail {
+class AtomicRefCnt {
+ public:
+  explicit AtomicRefCnt(uint64 cnt) : cnt_(cnt) {
+  }
+  void inc() {
+    cnt_.fetch_add(1, std::memory_order_relaxed);
+  }
+  bool dec() {
+    return cnt_.fetch_sub(1, std::memory_order_acq_rel) == 1;
+  }
+  uint64 value() const {
+    return cnt_.load(std::memory_order_relaxed);
+  }
+
+ private:
+  std::atomic<uint64> cnt_{0};
+};
+
+template <class DataT, class DeleterT>
+class SharedPtrRaw
+    : public DeleterT
+    , private MpscLinkQueueImpl::Node {
+ public:
+  explicit SharedPtrRaw(DeleterT deleter) : DeleterT(std::move(deleter)), ref_cnt_{0}, option_magic_(Magic) {
+  }
+
+  ~SharedPtrRaw() {
+    CHECK(use_cnt() == 0);
+    CHECK(option_magic_ == Magic);
+  }
+  template <class... ArgsT>
+  void init_data(ArgsT &&... args) {
+    new (&option_data_) DataT(std::forward<ArgsT>(args)...);
+  }
+  void destroy_data() {
+    option_data_.~DataT();
+    option_magic_ = Magic;
+  }
+  uint64 use_cnt() const {
+    return ref_cnt_.value();
+  }
+  void inc() {
+    ref_cnt_.inc();
+  }
+  bool dec() {
+    return ref_cnt_.dec();
+  }
+  DataT &data() {
+    return option_data_;
+  }
+  static SharedPtrRaw *from_mpsc_link_queue_node(MpscLinkQueueImpl::Node *node) {
+    return static_cast<SharedPtrRaw<DataT, DeleterT> *>(node);
+  }
+  MpscLinkQueueImpl::Node *to_mpsc_link_queue_node() {
+    return static_cast<MpscLinkQueueImpl::Node *>(this);
+  }
+
+ private:
+  AtomicRefCnt ref_cnt_;
+  enum { Magic = 0x732817a2 };
+  union {
+    DataT option_data_;
+    uint32 option_magic_;
+  };
+};
+
+template <class T, class DeleterT = std::default_delete<T>>
+class SharedPtr {
+ public:
+  using Raw = detail::SharedPtrRaw<T, DeleterT>;
+  SharedPtr() = default;
+  ~SharedPtr() {
+    if (!raw_) {
+      return;
+    }
+    reset();
+  }
+  explicit SharedPtr(Raw *raw) : raw_(raw) {
+    if (raw_) {
+      raw_->inc();
+    }
+  }
+  SharedPtr(const SharedPtr &other) : SharedPtr(other.raw_) {
+  }
+  SharedPtr &operator=(const SharedPtr &other) {
+    if (other.raw_) {
+      other.raw_->inc();
+    }
+    reset(other.raw_);
+    return *this;
+  }
+  SharedPtr(SharedPtr &&other) : raw_(other.raw_) {
+    other.raw_ = nullptr;
+  }
+  SharedPtr &operator=(SharedPtr &&other) {
+    reset(other.raw_);
+    other.raw_ = nullptr;
+    return *this;
+  }
+  bool empty() const {
+    return raw_ == nullptr;
+  }
+  explicit operator bool() const {
+    return !empty();
+  }
+  uint64 use_cnt() const {
+    if (!raw_) {
+      return 0;
+    }
+    return raw_->use_cnt();
+  }
+  T &operator*() const {
+    return raw_->data();
+  }
+  T *operator->() const {
+    return &raw_->data();
+  }
+
+  Raw *release() {
+    auto res = raw_;
+    raw_ = nullptr;
+    return res;
+  }
+
+  void reset(Raw *new_raw = nullptr) {
+    if (raw_ && raw_->dec()) {
+      raw_->destroy_data();
+      auto deleter = std::move(static_cast<DeleterT &>(*raw_));
+      deleter(raw_);
+    }
+    raw_ = new_raw;
+  }
+
+  template <class... ArgsT>
+  static SharedPtr<T, DeleterT> create(ArgsT &&... args) {
+    auto raw = make_unique<Raw>(DeleterT());
+    raw->init_data(std::forward<ArgsT>(args)...);
+    return SharedPtr<T, DeleterT>(raw.release());
+  }
+  template <class D, class... ArgsT>
+  static SharedPtr<T, DeleterT> create_with_deleter(D &&d, ArgsT &&... args) {
+    auto raw = make_unique<Raw>(std::forward<D>(d));
+    raw->init_data(std::forward<ArgsT>(args)...);
+    return SharedPtr<T, DeleterT>(raw.release());
+  }
+  bool operator==(const SharedPtr<T, DeleterT> &other) const {
+    return raw_ == other.raw_;
+  }
+
+ private:
+  Raw *raw_{nullptr};
+};
+
+}  // namespace detail
+
+template <class DataT>
+class SharedObjectPool {
+  class Deleter;
+
+ public:
+  using Ptr = detail::SharedPtr<DataT, Deleter>;
+
+  SharedObjectPool() = default;
+  SharedObjectPool(const SharedObjectPool &other) = delete;
+  SharedObjectPool &operator=(const SharedObjectPool &other) = delete;
+  SharedObjectPool(SharedObjectPool &&other) = delete;
+  SharedObjectPool &operator=(SharedObjectPool &&other) = delete;
+  ~SharedObjectPool() {
+    free_queue_.pop_all(free_queue_reader_);
+    size_t free_cnt = 0;
+    while (free_queue_reader_.read()) {
+      free_cnt++;
+    }
+    LOG_CHECK(free_cnt == allocated_.size()) << free_cnt << " " << allocated_.size();
+  }
+
+  template <class... ArgsT>
+  Ptr alloc(ArgsT &&... args) {
+    auto *raw = alloc_raw();
+    raw->init_data(std::forward<ArgsT>(args)...);
+    return Ptr(raw);
+  }
+  size_t total_size() const {
+    return allocated_.size();
+  }
+  uint64 calc_free_size() {
+    free_queue_.pop_all(free_queue_reader_);
+    return free_queue_reader_.calc_size();
+  }
+
+  //non thread safe
+  template <class F>
+  void for_each(F &&f) {
+    for (auto &raw : allocated_) {
+      if (raw->use_cnt() > 0) {
+        f(raw->data());
+      }
+    }
+  }
+
+ private:
+  using Raw = typename Ptr::Raw;
+  Raw *alloc_raw() {
+    free_queue_.pop_all(free_queue_reader_);
+    auto *raw = free_queue_reader_.read().get();
+    if (raw) {
+      return raw;
+    }
+    allocated_.push_back(make_unique<Raw>(deleter()));
+    return allocated_.back().get();
+  }
+
+  void free_raw(Raw *raw) {
+    free_queue_.push(Node{raw});
+  }
+
+  class Node {
+   public:
+    Node() = default;
+    explicit Node(Raw *raw) : raw_(raw) {
+    }
+
+    MpscLinkQueueImpl::Node *to_mpsc_link_queue_node() {
+      return raw_->to_mpsc_link_queue_node();
+    }
+    static Node from_mpsc_link_queue_node(MpscLinkQueueImpl::Node *node) {
+      return Node{Raw::from_mpsc_link_queue_node(node)};
+    }
+    Raw *get() const {
+      return raw_;
+    }
+    explicit operator bool() const {
+      return raw_ != nullptr;
+    }
+
+   private:
+    Raw *raw_{nullptr};
+  };
+
+  class Deleter {
+   public:
+    explicit Deleter(SharedObjectPool<DataT> *pool) : pool_(pool) {
+    }
+    void operator()(Raw *raw) {
+      pool_->free_raw(raw);
+    };
+
+   private:
+    SharedObjectPool<DataT> *pool_;
+  };
+  friend class Deleter;
+
+  Deleter deleter() {
+    return Deleter(this);
+  }
+
+  std::vector<unique_ptr<Raw>> allocated_;
+  MpscLinkQueue<Node> free_queue_;
+  typename MpscLinkQueue<Node>::Reader free_queue_reader_;
+};
+
+}  // namespace td