Rearrange sources (#4997)

include/xrpl/basics/CountedObject.h

@@ -0,0 +1,156 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#ifndef RIPPLE_BASICS_COUNTEDOBJECT_H_INCLUDED
+#define RIPPLE_BASICS_COUNTEDOBJECT_H_INCLUDED
+
+#include <ripple/beast/type_name.h>
+#include <atomic>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace ripple {
+
+/** Manages all counted object types. */
+class CountedObjects
+{
+public:
+    static CountedObjects&
+    getInstance() noexcept;
+
+    using Entry = std::pair<std::string, int>;
+    using List = std::vector<Entry>;
+
+    List
+    getCounts(int minimumThreshold) const;
+
+public:
+    /** Implementation for @ref CountedObject.
+
+        @internal
+    */
+    class Counter
+    {
+    public:
+        Counter(std::string name) noexcept : name_(std::move(name)), count_(0)
+        {
+            // Insert ourselves at the front of the lock-free linked list
+            CountedObjects& instance = CountedObjects::getInstance();
+            Counter* head;
+
+            do
+            {
+                head = instance.m_head.load();
+                next_ = head;
+            } while (instance.m_head.exchange(this) != head);
+
+            ++instance.m_count;
+        }
+
+        ~Counter() noexcept = default;
+
+        int
+        increment() noexcept
+        {
+            return ++count_;
+        }
+
+        int
+        decrement() noexcept
+        {
+            return --count_;
+        }
+
+        int
+        getCount() const noexcept
+        {
+            return count_.load();
+        }
+
+        Counter*
+        getNext() const noexcept
+        {
+            return next_;
+        }
+
+        std::string const&
+        getName() const noexcept
+        {
+            return name_;
+        }
+
+    private:
+        std::string const name_;
+        std::atomic<int> count_;
+        Counter* next_;
+    };
+
+private:
+    CountedObjects() noexcept;
+    ~CountedObjects() noexcept = default;
+
+private:
+    std::atomic<int> m_count;
+    std::atomic<Counter*> m_head;
+};
+
+//------------------------------------------------------------------------------
+
+/** Tracks the number of instances of an object.
+
+    Derived classes have their instances counted automatically. This is used
+    for reporting purposes.
+
+    @ingroup ripple_basics
+*/
+template <class Object>
+class CountedObject
+{
+private:
+    static auto&
+    getCounter() noexcept
+    {
+        static CountedObjects::Counter c{beast::type_name<Object>()};
+        return c;
+    }
+
+public:
+    CountedObject() noexcept
+    {
+        getCounter().increment();
+    }
+
+    CountedObject(CountedObject const&) noexcept
+    {
+        getCounter().increment();
+    }
+
+    CountedObject&
+    operator=(CountedObject const&) noexcept = default;
+
+    ~CountedObject() noexcept
+    {
+        getCounter().decrement();
+    }
+};
+
+}  // namespace ripple
+
+#endif