perf: Removed item cache - even with the slow-ish std::unordered_map, the cache is nearly useless.

Author: v-ein

src/dearpygui_commands.h

@@ -3273,10 +3273,7 @@ unstage(PyObject* self, PyObject* args, PyObject* kwargs)
 	}
 
 	if (item_found)
-	{
-		CleanUpItem(*GContext->itemRegistry, item);
 		return GetPyNone();
-	}
 
 	mvThrowPythonError(mvErrorCode::mvItemNotFound, "unstage",
 		"Stage not found: " + std::to_string(item), nullptr);

src/mvAppItem.cpp

@@ -45,7 +45,6 @@ mvAppItem::~mvAppItem()
                 GContext->itemRegistry->aliases.erase(config.alias);
         }
         GContext->itemRegistry->allItems.erase(uuid);
-        CleanUpItem(*GContext->itemRegistry, uuid);
     }
 }
 

src/mvItemRegistry.cpp

@@ -8,14 +8,11 @@
 
 mvItemRegistry::mvItemRegistry()
 {
-    // prefill cached containers
-    for (i32 i = 0; i < CachedContainerCount; i++)
-    {
-        cachedContainersID[i] = 0;
-        cachedContainersPTR[i] = nullptr;
-        cachedItemsID[i] = 0;
-        cachedItemsPTR[i] = nullptr;
-    }
+    // We seldom need to do a GetItem(0), and an explicit check for uuid == 0 in GetItem
+    // slows it down.  Instead of this, we add a fake entry to the allItems map,
+    // mapping 0 to nullptr.  This entry will never go away because map items are only
+    // removed in the mvAppItem destructor.
+    allItems[0] = nullptr;
 }
 
 static b8
@@ -47,25 +44,6 @@ TopParent(mvItemRegistry& registry)
     return nullptr;
 }
 
-static void
-CacheItem(mvItemRegistry& registry, mvAppItem* item)
-{
-    if (DearPyGui::GetEntityDesciptionFlags(item->type) & MV_ITEM_DESC_CONTAINER)
-    {
-        registry.cachedContainersID[registry.cachedContainerIndex] = item->uuid;
-        registry.cachedContainersPTR[registry.cachedContainerIndex] = item;
-        registry.cachedContainerIndex++;
-        if (registry.cachedContainerIndex == registry.CachedContainerCount)
-            registry.cachedContainerIndex = 0;
-    }
-
-    registry.cachedItemsID[registry.cachedItemsIndex] = item->uuid;
-    registry.cachedItemsPTR[registry.cachedItemsIndex] = item;
-    registry.cachedItemsIndex++;
-    if (registry.cachedItemsIndex == registry.CachedContainerCount)
-        registry.cachedItemsIndex = 0;
-}
-
 static void
 UpdateChildLocations(std::vector<std::shared_ptr<mvAppItem>>* children, i32 slots)
 {
@@ -310,10 +288,6 @@ RemoveItemFromTree(mvItemRegistry& registry, mvAppItem* item)
 b8
 DeleteItem(mvItemRegistry& registry, mvUUID uuid, b8 childrenOnly, i32 slot)
 {
-
-    // TODO: we probably don't need this anymore (well, only if we remove the cache)
-    CleanUpItem(registry, uuid);
-
     mvAppItem* item = GetItem(registry, uuid);
     if (!item)
     {
@@ -745,25 +719,6 @@ ClearItemRegistry(mvItemRegistry& registry)
     registry.viewportDrawlistRoots.clear();
 }
 
-void 
-CleanUpItem(mvItemRegistry& registry, mvUUID uuid)
-{
-    for (i32 i = 0; i < registry.CachedContainerCount; i++)
-    {
-        if (registry.cachedContainersID[i] == uuid)
-        {
-            registry.cachedContainersID[i] = 0;
-            registry.cachedContainersPTR[i] = nullptr;
-        }
-
-        if (registry.cachedItemsID[i] == uuid)
-        {
-            registry.cachedItemsID[i] = 0;
-            registry.cachedItemsPTR[i] = nullptr;
-        }
-    }
-}
-
 b8
 AddItemWithRuntimeChecks(mvItemRegistry& registry, std::shared_ptr<mvAppItem> item, mvUUID parent, mvUUID before)
 {
@@ -803,8 +758,6 @@ AddItemWithRuntimeChecks(mvItemRegistry& registry, std::shared_ptr<mvAppItem> it
 
     registry.lastItemAdded = item->uuid;
 
-    CacheItem(registry, item.get());
-
     //---------------------------------------------------------------------------
     // STEP 1: check if an item with this name exists (NO LONGER NEEDED)
     //---------------------------------------------------------------------------

src/mvItemRegistry.h

@@ -24,7 +24,6 @@ void             RenderItemRegistry(mvItemRegistry& registry);
 
 // cleanup
 void             ClearItemRegistry(mvItemRegistry& registry);
-void             CleanUpItem      (mvItemRegistry& registry, mvUUID uuid);
 b8               DeleteItem       (mvItemRegistry& registry, mvUUID uuid, b8 childrenOnly = false, i32 slot = -1);
 
 // aliases
@@ -64,18 +63,10 @@ b8               ReorderChildren         (mvItemRegistry& registry, mvUUID paren
 struct mvItemRegistry
 {
 
-    static constexpr i32 CachedContainerCount = 25;
-
-    // caching
+    // "last item" state
     mvUUID     lastItemAdded = 0;
     mvUUID     lastContainerAdded = 0;
     mvUUID     lastRootAdded = 0;
-    i32        cachedContainerIndex = 0;
-    i32        cachedItemsIndex = 0;
-    mvUUID     cachedItemsID[CachedContainerCount];
-    mvAppItem* cachedItemsPTR[CachedContainerCount];
-    mvUUID     cachedContainersID[CachedContainerCount];
-    mvAppItem* cachedContainersPTR[CachedContainerCount];
 
     // misc
     std::stack<mvAppItem*>                  containers;      // parent stack, top of stack becomes widget's parent

src/mvNodes.cpp

@@ -107,7 +107,6 @@ void mvNodeEditor::onChildRemoved(std::shared_ptr<mvAppItem> item)
                     if (i1 == attr_id || i2 == attr_id)
                     {
                         DeleteItem(*GContext->itemRegistry, child->uuid);
-                        CleanUpItem(*GContext->itemRegistry, child->uuid);
                     }
                 }
             }