Fixes from Walt's review comments

Author: zwoop

include/api/Metrics.h

@@ -50,8 +50,8 @@ class Metrics
     friend class Metrics;
 
   public:
-    AtomicType()          = default;
-    virtual ~AtomicType() = default;
+    AtomicType()  = default;
+    ~AtomicType() = default;
 
     int64_t
     load() const
@@ -296,6 +296,22 @@ class Metrics
     {
     };
 
+    static AtomicType *
+    lookup(const std::string_view name)
+    {
+      auto &instance = Metrics::instance();
+
+      return reinterpret_cast<AtomicType *>(instance.lookup(name));
+    }
+
+    static AtomicType *
+    lookup(const IdType id)
+    {
+      auto &instance = Metrics::instance();
+
+      return reinterpret_cast<AtomicType *>(instance.lookup(id));
+    }
+
     static Metrics::IdType
     create(const std::string_view name)
     {
@@ -335,7 +351,7 @@ class Metrics
     }
 
     static int64_t
-    load(AtomicType *metric)
+    load(const AtomicType *metric)
     {
       ink_assert(metric);
       return metric->_value.load();
@@ -360,6 +376,22 @@ class Metrics
     {
     };
 
+    static AtomicType *
+    lookup(const std::string_view name)
+    {
+      auto &instance = Metrics::instance();
+
+      return reinterpret_cast<AtomicType *>(instance.lookup(name));
+    }
+
+    static AtomicType *
+    lookup(const IdType id)
+    {
+      auto &instance = Metrics::instance();
+
+      return reinterpret_cast<AtomicType *>(instance.lookup(id));
+    }
+
     static Metrics::IdType
     create(const std::string_view name)
     {
@@ -392,7 +424,7 @@ class Metrics
     }
 
     static int64_t
-    load(AtomicType *metric)
+    load(const AtomicType *metric)
     {
       ink_assert(metric);
       return metric->_value.load();

src/proxy/http/PreWarmManager.cc

@@ -1178,7 +1178,7 @@ PreWarmManager::_register_stats(const PreWarm::ParsedSNIConf &parsed_conf)
           ++stats_counter;
         }
       } else {
-        metric = dynamic_cast<Metrics::Counter::AtomicType *>(metrics.lookup(stats_id));
+        metric = Metrics::Counter::lookup(stats_id);
       }
 
       counters[j] = metric;
@@ -1204,7 +1204,7 @@ PreWarmManager::_register_stats(const PreWarm::ParsedSNIConf &parsed_conf)
           ++stats_counter;
         }
       } else {
-        metric = dynamic_cast<Metrics::Gauge::AtomicType *>(metrics.lookup(stats_id));
+        metric = Metrics::Gauge::lookup(stats_id);
       }
 
       gauges[j] = metric;