Thread-local state

src/dearpygui_commands.h

@@ -2519,8 +2519,9 @@ setup_dearpygui(PyObject* self, PyObject* args, PyObject* kwargs)
 		return nullptr;
 	}
 
-	while (!GContext->itemRegistry->containers.empty())
-		GContext->itemRegistry->containers.pop();
+	// Clear the containers stack. Unfortunately std::stack doesn't have a clear() call,
+	// but assigning a new empty stack does just the same.
+	mvItemRegistry::threadContext.containers = {};
 	GContext->started = true;
 	GContext->running = true;
 	GContext->future = std::async(std::launch::async, []() {return mvRunCallbacks(); });
@@ -2924,18 +2925,19 @@ pop_container_stack(PyObject* self, PyObject* args, PyObject* kwargs)
 
 	mvPySafeLockGuard lk(GContext->mutex);
 
-	if (GContext->itemRegistry->containers.empty())
+	auto& containers = mvItemRegistry::threadContext.containers;
+	if (containers.empty())
 	{
 		mvThrowPythonError(mvErrorCode::mvContainerStackEmpty, "No container to pop.");
 		assert(false);
 		return nullptr;
 	}
 
-	mvAppItem* item = GContext->itemRegistry->containers.top();
-	GContext->itemRegistry->containers.pop();
+	mvAppItem* item = containers.top();
+	containers.pop();
 
 	if (item)
-		return ToPyUUID(item->uuid);
+		return ToPyUUID(item);
 	else
 		return GetPyNone();
 
@@ -2945,8 +2947,9 @@ static PyObject*
 empty_container_stack(PyObject* self, PyObject* args, PyObject* kwargs)
 {
 	mvPySafeLockGuard lk(GContext->mutex);
-	while (!GContext->itemRegistry->containers.empty())
-		GContext->itemRegistry->containers.pop();
+	// Clear the containers stack. Unfortunately std::stack doesn't have a clear() call,
+	// but assigning a new empty stack does just the same.
+	mvItemRegistry::threadContext.containers = {};
 	return GetPyNone();
 }
 
@@ -2956,11 +2959,12 @@ top_container_stack(PyObject* self, PyObject* args, PyObject* kwargs)
 	mvPySafeLockGuard lk(GContext->mutex);
 
 	mvAppItem* item = nullptr;
-	if (!GContext->itemRegistry->containers.empty())
-		item = GContext->itemRegistry->containers.top();
+	auto& containers = mvItemRegistry::threadContext.containers;
+	if (!containers.empty())
+		item = containers.top();
 
 	if (item)
-		return ToPyUUID(item->uuid);
+		return ToPyUUID(item);
 	else
 		return GetPyNone();
 }
@@ -2970,23 +2974,23 @@ last_item(PyObject* self, PyObject* args, PyObject* kwargs)
 {
 	mvPySafeLockGuard lk(GContext->mutex);
 
-	return ToPyUUID(GContext->itemRegistry->lastItemAdded);
+	return ToPyUUID(mvItemRegistry::threadContext.lastItemAdded);
 }
 
 static PyObject*
 last_container(PyObject* self, PyObject* args, PyObject* kwargs)
 {
 	mvPySafeLockGuard lk(GContext->mutex);
 
-	return ToPyUUID(GContext->itemRegistry->lastContainerAdded);
+	return ToPyUUID(mvItemRegistry::threadContext.lastContainerAdded);
 }
 
 static PyObject*
 last_root(PyObject* self, PyObject* args, PyObject* kwargs)
 {
 	mvPySafeLockGuard lk(GContext->mutex);
 
-	return ToPyUUID(GContext->itemRegistry->lastRootAdded);
+	return ToPyUUID(mvItemRegistry::threadContext.lastRootAdded);
 }
 
 static PyObject*
@@ -3006,7 +3010,7 @@ push_container_stack(PyObject* self, PyObject* args, PyObject* kwargs)
 	{
 		if (DearPyGui::GetEntityDesciptionFlags(parent->type) & MV_ITEM_DESC_CONTAINER)
 		{
-			GContext->itemRegistry->containers.push(parent);
+			mvItemRegistry::threadContext.containers.push(parent);
 			return ToPyBool(true);
 		}
 	}
@@ -4164,8 +4168,8 @@ capture_next_item(PyObject* self, PyObject* args, PyObject* kwargs)
 
 	mvPySafeLockGuard lk(GContext->mutex);
 
-	GContext->itemRegistry->captureCallback = mvPyObject(callable == Py_None? nullptr : callable, true);
-	GContext->itemRegistry->captureCallbackUserData = mvPyObject(user_data, true);
+	mvItemRegistry::threadContext.captureCallback = mvPyObject(callable == Py_None? nullptr : callable, true);
+	mvItemRegistry::threadContext.captureCallbackUserData = mvPyObject(user_data, true);
 
 	return GetPyNone();
 }

src/mvContext.h

@@ -115,7 +115,7 @@ struct mvContext
     double              time      = 0.0;    // total time since starting
     int                 frame     = 0;      // frame count
     int                 framerate = 0;      // frame rate
-    mvUUID              id = MV_START_UUID; // current ID
+    std::atomic<mvUUID> id = MV_START_UUID; // current ID
     mvViewport*         viewport = nullptr;
     mvGraphics          graphics;
     bool                resetTheme = false;

src/mvItemRegistry.cpp

@@ -12,6 +12,8 @@
 
 #include "mvProfiler.h"
 
+thread_local mvThreadContext mvItemRegistry::threadContext;
+
 mvItemRegistry::mvItemRegistry()
 {
     // We seldom need to do a GetItem(0), and an explicit check for uuid == 0 in GetItem
@@ -36,17 +38,12 @@ DebugItem(const char* label, const char* item) {
     ImGui::TextColored(ImVec4(1.0f, 0.0f, 1.0f, 1.0f), "%s", item);
 }
 
-static void
-PushParent(mvItemRegistry& registry, mvAppItem* item)
-{
-    registry.containers.push(item);
-}
-
 static mvAppItem*
 TopParent(mvItemRegistry& registry)
 {
-    if (!registry.containers.empty())
-        return registry.containers.top();
+	auto& containers = mvItemRegistry::threadContext.containers;
+    if (!containers.empty())
+        return containers.top();
     return nullptr;
 }
 
@@ -328,9 +325,10 @@ DeleteItem(mvItemRegistry& registry, mvUUID uuid, b8 childrenOnly, i32 slot)
     }
 
     // See if it is the captured item
-    if (registry.capturedItem && registry.capturedItem.get() == item)
+    auto& capturedItem = mvItemRegistry::threadContext.capturedItem;
+    if (capturedItem && capturedItem.get() == item)
     {
-        registry.capturedItem = nullptr;
+        capturedItem = nullptr;
         return true;
     }
 
@@ -352,10 +350,11 @@ MoveItem(mvItemRegistry& registry, mvUUID uuid, mvUUID parent, mvUUID before)
 
     std::shared_ptr<mvAppItem> child = nullptr;
 
-    if (registry.capturedItem && registry.capturedItem->uuid == uuid)
+    auto& capturedItem = mvItemRegistry::threadContext.capturedItem;
+    if (capturedItem && capturedItem->uuid == uuid)
     {
-        child = registry.capturedItem;
-        registry.capturedItem = nullptr;
+        child = capturedItem;
+        capturedItem = nullptr;
     }
     else
     {
@@ -652,8 +651,9 @@ mvAppItem*
 GetItem(mvItemRegistry& registry, mvUUID uuid)
 {
     // check captured
-    if (registry.capturedItem && registry.capturedItem->uuid == uuid)
-        return registry.capturedItem.get();
+    auto& capturedItem = mvItemRegistry::threadContext.capturedItem;
+    if (capturedItem && capturedItem->uuid == uuid)
+        return capturedItem.get();
 
     auto found = registry.allItems.find(uuid);
     return found != registry.allItems.end()? found->second : nullptr;
@@ -706,16 +706,18 @@ b8
 AddItemWithRuntimeChecks(mvItemRegistry& registry, std::shared_ptr<mvAppItem> item, mvUUID parent, mvUUID before)
 {
 
-    if(registry.captureCallback)
+    auto& threadContext = mvItemRegistry::threadContext;
+
+    if (threadContext.captureCallback)
     {
 
         // this is a unique situation in that the caller always has the GIL
-        registry.capturedItem = item;
+        threadContext.capturedItem = item;
         // resetting captureCallback in advance in order to avoid recursion (if the callback
         // attempts to add another item or move an item)
-        mvPyObject captureCallback(std::move(registry.captureCallback));
-        registry.captureCallback = nullptr;
-        mvRunCallback(captureCallback, nullptr, registry.capturedItem->uuid);
+        mvPyObject captureCallback(std::move(threadContext.captureCallback));
+        threadContext.captureCallback = nullptr;
+        mvRunCallback(captureCallback, nullptr, threadContext.capturedItem->uuid);
         return true;
     }
 
@@ -733,13 +735,13 @@ AddItemWithRuntimeChecks(mvItemRegistry& registry, std::shared_ptr<mvAppItem> it
     //---------------------------------------------------------------------------
     if (DearPyGui::GetEntityDesciptionFlags(item->type) & MV_ITEM_DESC_ROOT)
     {
-        registry.lastRootAdded = item->uuid;
-        registry.lastContainerAdded = item->uuid;
+        threadContext.lastRootAdded = item->uuid;
+        threadContext.lastContainerAdded = item->uuid;
     }
     else if (DearPyGui::GetEntityDesciptionFlags(item->type) & MV_ITEM_DESC_CONTAINER)
-        registry.lastContainerAdded = item->uuid;
+        threadContext.lastContainerAdded = item->uuid;
 
-    registry.lastItemAdded = item->uuid;
+    threadContext.lastItemAdded = item->uuid;
 
     //---------------------------------------------------------------------------
     // STEP 1: check if an item with this name exists (NO LONGER NEEDED)

src/mvItemRegistry.h

@@ -48,6 +48,25 @@ b8               AddItemWithRuntimeChecks(mvItemRegistry& registry, std::shared_
 void             ResetTheme              (mvItemRegistry& registry);
 b8               ReorderChildren         (mvItemRegistry& registry, mvUUID parent, i32 slot, const std::vector<mvUUID>& new_order);
 
+//-----------------------------------------------------------------------------
+// mvThreadContext
+//     - Holds thread-local data used together with mvItemRegistry
+//-----------------------------------------------------------------------------
+
+struct mvThreadContext
+{
+    // "last item" state
+    mvUUID     lastItemAdded = 0;
+    mvUUID     lastContainerAdded = 0;
+    mvUUID     lastRootAdded = 0;
+
+    std::stack<mvAppItem*>                  containers;      // parent stack, top of stack becomes widget's parent
+
+    std::shared_ptr<mvAppItem>              capturedItem = nullptr;
+    mvPyObject                              captureCallback = nullptr;
+    mvPyObject                              captureCallbackUserData = nullptr;
+};
+
 //-----------------------------------------------------------------------------
 // mvItemRegistry
 //     - Responsibilities:
@@ -61,21 +80,16 @@ b8               ReorderChildren         (mvItemRegistry& registry, mvUUID paren
 struct mvItemRegistry
 {
 
-    // "last item" state
-    mvUUID     lastItemAdded = 0;
-    mvUUID     lastContainerAdded = 0;
-    mvUUID     lastRootAdded = 0;
-
     // misc
-    std::stack<mvAppItem*>                  containers;      // parent stack, top of stack becomes widget's parent
     std::unordered_map<std::string, mvUUID> aliases;
     std::unordered_map<mvUUID, mvAppItem*>  allItems;        // used for quick access to items by UUID
+
+    static thread_local mvThreadContext     threadContext;
+
+    // debug items
     b8                                      showImGuiDebug = false;
     b8                                      showImPlotDebug = false;
-    std::vector<std::shared_ptr<mvAppItem>>           debugWindows;
-    std::shared_ptr<mvAppItem>                        capturedItem = nullptr;
-    mvPyObject                              captureCallback = nullptr;
-    mvPyObject                              captureCallbackUserData = nullptr;
+    std::vector<std::shared_ptr<mvAppItem>> debugWindows;
 
     // roots
     std::vector<std::shared_ptr<mvAppItem>> colormapRoots;