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tdutils/td/utils/ThreadSafeCounter.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/ThreadLocalStorage.h"
+#include "td/utils/StringBuilder.h"
+
+#include <array>
+#include <mutex>
+
+namespace td {
+template <size_t N>
+class ThreadSafeMultiCounter {
+ public:
+  void add(size_t index, int64 diff) {
+    CHECK(index < N);
+    tls_.get()[index].fetch_add(diff, std::memory_order_relaxed);
+  }
+
+  int64 sum(size_t index) const {
+    CHECK(index < N);
+    int64 res = 0;
+    tls_.for_each([&](auto &value) { res += value[index].load(); });
+    return res;
+  }
+
+ private:
+  ThreadLocalStorage<std::array<std::atomic<int64>, N>> tls_;
+};
+
+class ThreadSafeCounter {
+ public:
+  void add(int64 diff) {
+    counter_.add(0, diff);
+  }
+
+  int64 sum() const {
+    return counter_.sum(0);
+  }
+
+ private:
+  ThreadSafeMultiCounter<1> counter_;
+};
+
+class NamedThreadSafeCounter {
+  static constexpr int N = 128;
+  using Counter = ThreadSafeMultiCounter<N>;
+
+ public:
+  class CounterRef {
+   public:
+    CounterRef() = default;
+    CounterRef(size_t index, Counter *counter) : index_(index), counter_(counter) {
+    }
+    void add(int64 diff) {
+      counter_->add(index_, diff);
+    }
+    int64 sum() const {
+      return counter_->sum(index_);
+    }
+
+   private:
+    size_t index_{0};
+    Counter *counter_{nullptr};
+  };
+
+  CounterRef get_counter(Slice name) {
+    std::unique_lock<std::mutex> guard(mutex_);
+    for (size_t i = 0; i < names_.size(); i++) {
+      if (names_[i] == name) {
+        return get_counter_ref(i);
+      }
+    }
+    CHECK(names_.size() < N);
+    names_.push_back(name.str());
+    return get_counter_ref(names_.size() - 1);
+  }
+
+  CounterRef get_counter_ref(size_t index) {
+    return CounterRef(index, &counter_);
+  }
+
+  static NamedThreadSafeCounter &get_default() {
+    static NamedThreadSafeCounter res;
+    return res;
+  }
+
+  template <class F>
+  void for_each(F &&f) const {
+    std::unique_lock<std::mutex> guard(mutex_);
+    for (size_t i = 0; i < names_.size(); i++) {
+      f(names_[i], counter_.sum(i));
+    }
+  }
+
+  friend StringBuilder &operator<<(StringBuilder &sb, const NamedThreadSafeCounter &counter) {
+    counter.for_each([&sb](Slice name, int64 cnt) { sb << name << ": " << cnt << "\n"; });
+    return sb;
+  }
+
+ private:
+  mutable std::mutex mutex_;
+  std::vector<std::string> names_;
+
+  Counter counter_;
+};
+
+}  // namespace td