add LeakDetector

iface/CMakeLists.txt

@@ -13,6 +13,7 @@ target_sources(nf7_iface
     common/container.hh
     common/exception.hh
     common/future.hh
+    common/leak_detector.hh
     common/observer.hh
     common/task.hh
     common/task_context.hh
@@ -33,6 +34,7 @@ target_sources(nf7_iface_test
     common/dealer_test.cc
     common/container_test.cc
     common/future_test.cc
+    common/leak_detector_test.cc
     common/observer_test.cc
     common/observer_test.hh
     common/task_test.cc

iface/common/leak_detector.hh

@@ -0,0 +1,45 @@
+// No copyright
+#pragma once
+
+#include <atomic>
+#include <cassert>
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+
+namespace nf7 {
+#if !defined(NDEBUG)
+
+  template <typename T>
+  class LeakDetector {
+   public:
+    LeakDetector() { (void) checker_; ++count_; }
+    virtual ~LeakDetector() noexcept { --count_; }
+
+   private:
+    struct Checker {
+      ~Checker() {
+        if (count_ > 0) {
+          std::cerr << "LEAK DETECTED: " << typeid(T).name() << std::endl;
+        }
+      }
+    };
+
+   public:
+    static uint64_t count() noexcept { return count_; }
+
+   private:
+    static inline Checker               checker_;
+    static inline std::atomic<uint64_t> count_ = 0;
+  };
+
+#else
+
+  template <typename T>
+  class LeakDetector {
+   public:
+    static uint64_t count() noexcept { return 0; }
+  };
+
+#endif
+}  // namespace nf7

iface/common/leak_detector_test.cc

@@ -0,0 +1,21 @@
+// No copyright
+#include "iface/common/leak_detector.hh"
+
+#include <gtest/gtest.h>
+
+#include <memory>
+
+
+namespace {
+class A : private nf7::LeakDetector<A> { };
+}  // namespace
+
+#if !defined(NDEBUG)
+TEST(LeakDetector, Counter) {
+  {
+    A a;
+    EXPECT_EQ(nf7::LeakDetector<A>::count(), 1);
+  }
+  EXPECT_EQ(nf7::LeakDetector<A>::count(), 0);
+}
+#endif