Rearrange sources (#4997)

include/xrpl/beast/insight/Gauge.h

@@ -0,0 +1,147 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of Beast: https://github.com/vinniefalco/Beast
+    Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
+
+    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 BEAST_INSIGHT_GAUGE_H_INCLUDED
+#define BEAST_INSIGHT_GAUGE_H_INCLUDED
+
+#include <ripple/beast/insight/GaugeImpl.h>
+
+#include <memory>
+
+namespace beast {
+namespace insight {
+
+/** A metric for measuring an integral value.
+
+    A gauge is an instantaneous measurement of a value, like the gas gauge
+    in a car. The caller directly sets the value, or adjusts it by a
+    specified amount. The value is kept in the client rather than the collector.
+
+    This is a lightweight reference wrapper which is cheap to copy and assign.
+    When the last reference goes away, the metric is no longer collected.
+*/
+class Gauge final
+{
+public:
+    using value_type = GaugeImpl::value_type;
+    using difference_type = GaugeImpl::difference_type;
+
+    /** Create a null metric.
+        A null metric reports no information.
+    */
+    Gauge()
+    {
+    }
+
+    /** Create the metric reference the specified implementation.
+        Normally this won't be called directly. Instead, call the appropriate
+        factory function in the Collector interface.
+        @see Collector.
+    */
+    explicit Gauge(std::shared_ptr<GaugeImpl> const& impl) : m_impl(impl)
+    {
+    }
+
+    /** Set the value on the gauge.
+        A Collector implementation should combine multiple calls to value
+        changes into a single change if the calls occur within a single
+        collection interval.
+    */
+    /** @{ */
+    void
+    set(value_type value) const
+    {
+        if (m_impl)
+            m_impl->set(value);
+    }
+
+    Gauge const&
+    operator=(value_type value) const
+    {
+        set(value);
+        return *this;
+    }
+    /** @} */
+
+    /** Adjust the value of the gauge. */
+    /** @{ */
+    void
+    increment(difference_type amount) const
+    {
+        if (m_impl)
+            m_impl->increment(amount);
+    }
+
+    Gauge const&
+    operator+=(difference_type amount) const
+    {
+        increment(amount);
+        return *this;
+    }
+
+    Gauge const&
+    operator-=(difference_type amount) const
+    {
+        increment(-amount);
+        return *this;
+    }
+
+    Gauge const&
+    operator++() const
+    {
+        increment(1);
+        return *this;
+    }
+
+    Gauge const&
+    operator++(int) const
+    {
+        increment(1);
+        return *this;
+    }
+
+    Gauge const&
+    operator--() const
+    {
+        increment(-1);
+        return *this;
+    }
+
+    Gauge const&
+    operator--(int) const
+    {
+        increment(-1);
+        return *this;
+    }
+    /** @} */
+
+    std::shared_ptr<GaugeImpl> const&
+    impl() const
+    {
+        return m_impl;
+    }
+
+private:
+    std::shared_ptr<GaugeImpl> m_impl;
+};
+
+}  // namespace insight
+}  // namespace beast
+
+#endif