From 863f704f479038a1b7f47a5cbb2fe32bd44b922d Mon Sep 17 00:00:00 2001
From: Luiz Siqueira <indiosmo@gmail.com>
Date: Tue, 14 Aug 2018 08:51:20 -0300
Subject: [PATCH] increment counter every time we overrid a message in async
 mode.

---
 include/spdlog/details/circular_q.h      | 8 ++++++++
 include/spdlog/details/mpmc_blocking_q.h | 5 +++++
 include/spdlog/details/thread_pool.h     | 5 +++++
 tests/test_async.cpp                     | 4 ++++
 4 files changed, 22 insertions(+)

diff --git a/include/spdlog/details/circular_q.h b/include/spdlog/details/circular_q.h
index 6f3433a2..cea12174 100644
--- a/include/spdlog/details/circular_q.h
+++ b/include/spdlog/details/circular_q.h
@@ -31,6 +31,7 @@ public:
         if (tail_ == head_) // overrun last item if full
         {
             head_ = (head_ + 1) % max_items_;
+            ++overrun_counter_;
         }
     }
 
@@ -53,12 +54,19 @@ public:
         return ((tail_ + 1) % max_items_) == head_;
     }
 
+    int overrun_counter() const
+    {
+      return overrun_counter_;
+    }
+
 private:
     size_t max_items_;
     typename std::vector<T>::size_type head_ = 0;
     typename std::vector<T>::size_type tail_ = 0;
 
     std::vector<T> v_;
+
+    int overrun_counter_ = 0;
 };
 } // namespace details
 } // namespace spdlog
diff --git a/include/spdlog/details/mpmc_blocking_q.h b/include/spdlog/details/mpmc_blocking_q.h
index d607da2c..3aa9fa1b 100644
--- a/include/spdlog/details/mpmc_blocking_q.h
+++ b/include/spdlog/details/mpmc_blocking_q.h
@@ -30,6 +30,11 @@ public:
     {
     }
 
+    int overrun_counter() const
+    {
+      return q_.overrun_counter();
+    }
+
 #ifndef __MINGW32__
     // try to enqueue and block if no room left
     void enqueue(T &&item)
diff --git a/include/spdlog/details/thread_pool.h b/include/spdlog/details/thread_pool.h
index b45b6d2b..fd47eed2 100644
--- a/include/spdlog/details/thread_pool.h
+++ b/include/spdlog/details/thread_pool.h
@@ -157,6 +157,11 @@ public:
         post_async_msg_(async_msg(std::move(worker_ptr), async_msg_type::flush), overflow_policy);
     }
 
+    int overrun_counter() const
+    {
+      return q_.overrun_counter();
+    }
+
 private:
     q_type q_;
 
diff --git a/tests/test_async.cpp b/tests/test_async.cpp
index c4324df4..91be8bd9 100644
--- a/tests/test_async.cpp
+++ b/tests/test_async.cpp
@@ -7,6 +7,7 @@ TEST_CASE("basic async test ", "[async]")
 {
     using namespace spdlog;
     auto test_sink = std::make_shared<sinks::test_sink_mt>();
+    int overrun_counter = 0;
     size_t queue_size = 128;
     size_t messages = 256;
     {
@@ -17,9 +18,11 @@ TEST_CASE("basic async test ", "[async]")
             logger->info("Hello message #{}", i);
         }
         logger->flush();
+        overrun_counter = tp->overrun_counter();
     }
     REQUIRE(test_sink->msg_counter() == messages);
     REQUIRE(test_sink->flush_counter() == 1);
+    REQUIRE(overrun_counter == 0);
 }
 
 TEST_CASE("discard policy ", "[async]")
@@ -37,6 +40,7 @@ TEST_CASE("discard policy ", "[async]")
         logger->info("Hello message");
     }
     REQUIRE(test_sink->msg_counter() < messages);
+    REQUIRE(tp->overrun_counter() > 0);
 }
 
 TEST_CASE("discard policy using factory ", "[async]")