From 96eb8e8b0bcd192592d960647e402e953ee2f4d1 Mon Sep 17 00:00:00 2001
From: Andrew Noyes <andrew@weaselab.dev>
Date: Tue, 2 Sep 2025 15:25:38 -0400
Subject: [PATCH] Fix memory leaks

---
 src/metric.cpp | 51 +++++++++++++++++++++++++-------------------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/src/metric.cpp b/src/metric.cpp
index dca4af9..4b3fee0 100644
--- a/src/metric.cpp
+++ b/src/metric.cpp
@@ -329,19 +329,23 @@ struct Metric {
 
   // Global arena allocator for metric families and persistent global state
   static ArenaAllocator &get_global_arena() {
-    static ArenaAllocator global_arena(64 * 1024); // 64KB initial size
-    return global_arena;
+    static auto *global_arena =
+        new ArenaAllocator(64 * 1024); // 64KB initial size
+    return *global_arena;
   }
 
   // Function-local statics to avoid static initialization order fiasco
   static auto &get_counter_families() {
-    using FamilyMap = std::map<
-        std::string_view, Family<Counter>::State *, std::less<std::string_view>,
-        ArenaStlAllocator<
-            std::pair<const std::string_view, Family<Counter>::State *>>>;
-    static FamilyMap *counterFamilies = new FamilyMap(
-        ArenaStlAllocator<
-            std::pair<const std::string_view, Family<Counter>::State *>>(
+    using FamilyMap =
+        std::map<std::string_view, ArenaAllocator::Ptr<Family<Counter>::State>,
+                 std::less<std::string_view>,
+                 ArenaStlAllocator<
+                     std::pair<const std::string_view,
+                               ArenaAllocator::Ptr<Family<Counter>::State>>>>;
+    static FamilyMap *counterFamilies =
+        new FamilyMap(ArenaStlAllocator<
+                      std::pair<const std::string_view,
+                                ArenaAllocator::Ptr<Family<Counter>::State>>>(
             &get_global_arena()));
     return *counterFamilies;
   }
@@ -360,13 +364,16 @@ struct Metric {
 
   static auto &get_histogram_families() {
     using FamilyMap =
-        std::map<std::string_view, Family<Histogram>::State *,
+        std::map<std::string_view,
+                 ArenaAllocator::Ptr<Family<Histogram>::State>,
                  std::less<std::string_view>,
-                 ArenaStlAllocator<std::pair<const std::string_view,
-                                             Family<Histogram>::State *>>>;
-    static FamilyMap *histogramFamilies = new FamilyMap(
-        ArenaStlAllocator<
-            std::pair<const std::string_view, Family<Histogram>::State *>>(
+                 ArenaStlAllocator<
+                     std::pair<const std::string_view,
+                               ArenaAllocator::Ptr<Family<Histogram>::State>>>>;
+    static FamilyMap *histogramFamilies =
+        new FamilyMap(ArenaStlAllocator<
+                      std::pair<const std::string_view,
+                                ArenaAllocator::Ptr<Family<Histogram>::State>>>(
             &get_global_arena()));
     return *histogramFamilies;
   }
@@ -872,11 +879,7 @@ Family<Counter> create_counter(std::string_view name, std::string_view help) {
   auto name_view = arena_copy_string(name, global_arena);
   auto &familyPtr = Metric::get_counter_families()[name_view];
   if (!familyPtr) {
-    // NOTE: Family<T>::State instances are never destroyed - this is fine
-    // because the number of metric families is bounded by application design
-    familyPtr = new (global_arena.allocate_raw(sizeof(Family<Counter>::State),
-                                               alignof(Family<Counter>::State)))
-        Family<Counter>::State(global_arena);
+    familyPtr = global_arena.construct<Family<Counter>::State>(global_arena);
     familyPtr->name = name_view;
     familyPtr->help = arena_copy_string(help, global_arena);
   } else {
@@ -885,7 +888,7 @@ Family<Counter> create_counter(std::string_view name, std::string_view help) {
         "metric family already registered with different help text", name);
   }
   Family<Counter> family;
-  family.p = familyPtr;
+  family.p = familyPtr.get();
   return family;
 }
 
@@ -925,9 +928,7 @@ Family<Histogram> create_histogram(std::string_view name, std::string_view help,
   if (!family_ptr) {
     // NOTE: Family<T>::State instances are never destroyed - this is fine
     // because the number of metric families is bounded by application design
-    family_ptr = new (global_arena.allocate_raw(
-        sizeof(Family<Histogram>::State), alignof(Family<Histogram>::State)))
-        Family<Histogram>::State(global_arena);
+    family_ptr = global_arena.construct<Family<Histogram>::State>(global_arena);
     family_ptr->name = name_view;
     family_ptr->help = arena_copy_string(help, global_arena);
 
@@ -971,7 +972,7 @@ Family<Histogram> create_histogram(std::string_view name, std::string_view help,
                       name);
   }
   Family<Histogram> family;
-  family.p = family_ptr;
+  family.p = family_ptr.get();
   return family;
 }