DeepFactory counts the number of active Deep objects

3 files changed, 19 insertions, 0 deletions

diff --git a/deep_test/deep_test.cpp b/deep_test/deep_test.cpp
index 0c7ed0f..dbc0115 100644
--- a/deep_test/deep_test.cpp
+++ b/deep_test/deep_test.cpp
@@ -8,6 +8,8 @@ class MyDeepFactory : public DeepFactory
     static MyDeepFactory Instance;
 
     private:
+
+    private:
     void createMetatable(lua_State* const L_) const override
     {
         luaL_getmetatable(L_, "deep");
@@ -164,6 +166,14 @@ static luaL_Reg const deep_mt[] = {
 
 // #################################################################################################
 
+int luaD_get_deep_count(lua_State* const L_)
+{
+    lua_pushinteger(L_, MyDeepFactory::Instance.getObjectCount());
+    return 1;
+}
+
+// #################################################################################################
+
 int luaD_new_deep(lua_State* L)
 {
     UserValueCount const _nuv{ static_cast<int>(luaL_optinteger(L, 1, 0)) };
@@ -296,6 +306,7 @@ int luaD_new_clonable(lua_State* L)
 // #################################################################################################
 
 static luaL_Reg const deep_module[] = {
+    { "get_deep_count", luaD_get_deep_count }, 
     { "new_deep", luaD_new_deep },
     { "new_clonable", luaD_new_clonable },
     { nullptr, nullptr }
diff --git a/src/deep.cpp b/src/deep.cpp
index 398e13f..bc0b73c 100644
--- a/src/deep.cpp
+++ b/src/deep.cpp
@@ -131,6 +131,7 @@ int DeepFactory::DeepGC(lua_State* const L_)
 void DeepFactory::DeleteDeepObject(lua_State* const L_, DeepPrelude* const o_)
 {
     STACK_CHECK_START_REL(L_, 0);
+    o_->factory.deepObjectCount.fetch_sub(1, std::memory_order_relaxed);
     o_->factory.deleteDeepObjectInternal(L_, o_);
     STACK_CHECK(L_, 0);
 }
@@ -318,6 +319,7 @@ void DeepFactory::pushDeepUserdata(DestState const L_, UserValueCount const nuv_
     if (_prelude == nullptr) {
         raise_luaL_error(L_, "DeepFactory::newDeepObjectInternal failed to create deep userdata (out of memory)");
     }
+    deepObjectCount.fetch_add(1, std::memory_order_relaxed);
 
     if (_prelude->magic != kDeepVersion) {
         // just in case, don't leak the newly allocated deep userdata object
diff --git a/src/deep.hpp b/src/deep.hpp
index 6bc3b20..8196e66 100644
--- a/src/deep.hpp
+++ b/src/deep.hpp
@@ -50,6 +50,10 @@ class DeepPrelude
 // external C modules should create a single object implementing that interface for each Deep userdata class they want to expose
 class DeepFactory
 {
+    private:
+    // the current count of deep object instances
+    mutable std::atomic<int> deepObjectCount{};
+
     protected:
     // protected non-virtual destructor: Lanes won't manage the Factory's lifetime
     DeepFactory() = default;
@@ -80,6 +84,8 @@ class DeepFactory
     // NVI: public interface
     static void DeleteDeepObject(lua_State* L_, DeepPrelude* o_);
     [[nodiscard]]
+    int getObjectCount() const { return deepObjectCount.load(std::memory_order_relaxed); }
+    [[nodiscard]]
     static bool IsDeepUserdata(lua_State* const L_, StackIndex const idx_);
     [[nodiscard]]
     static DeepFactory* LookupFactory(lua_State* L_, StackIndex index_, LookupMode mode_);