C_AddOns.IsAddOnLoaded

Author: brues-code

AddOns/!!!ClassicAPI/Util/EventUtil.lua

@@ -83,12 +83,11 @@ function EventUtil.TriggerOnVariablesLoaded()
 end
 
 function EventUtil.ContinueOnAddOnLoaded(addOnName, callback)
-    -- 1.12's IsAddOnLoaded returns a single bool. 3.3.5 split that into
-    -- (isLoadedOrLoading, isLoaded); treat truthy as "ready to use".
-    if IsAddOnLoaded(addOnName) then
-        callback()
-        return
-    end
+	local isLoadedOrLoading, isLoaded = C_AddOns.IsAddOnLoaded(addOnName)
+	if isLoaded then
+		callback();
+		return;
+	end
 
     EventUtil.RegisterOnceFrameEventAndCallback("ADDON_LOADED", callback, addOnName)
 end

README.md

@@ -18,7 +18,7 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | Namespace | Calls |
 |-----------|-------|
 | [Action](docs/API.md#action) | `GetActionInfo` |
-| [AddOns](docs/API.md#addons) | `C_AddOns.DoesAddOnExist`, `C_AddOns.GetAddOnName`, `C_AddOns.GetAddOnNotes`, `C_AddOns.GetAddOnSecurity`, `C_AddOns.GetAddOnTitle`, `C_AddOns.IsAddOnLoadable` |
+| [AddOns](docs/API.md#addons) | `C_AddOns.DoesAddOnExist`, `C_AddOns.GetAddOnName`, `C_AddOns.GetAddOnNotes`, `C_AddOns.GetAddOnSecurity`, `C_AddOns.GetAddOnTitle`, `C_AddOns.IsAddOnLoadable`, `C_AddOns.IsAddOnLoaded` |
 | [Chat](docs/API.md#chat) | `GetCurrentChatGUID` |
 | [Class](docs/API.md#class) | `FillLocalizedClassList` |
 | [Combat](docs/API.md#combat) | `InCombatLockdown` |

docs/API.md

@@ -17,6 +17,7 @@ build instructions.
   - [`C_AddOns.GetAddOnTitle(indexOrName)`](#c_addonsgetaddontitleindexorname)
   - [`C_AddOns.GetAddOnNotes(indexOrName)`](#c_addonsgetaddonnotesindexorname)
   - [`C_AddOns.IsAddOnLoadable(indexOrName)`](#c_addonsisaddonloadableindexorname)
+  - [`C_AddOns.IsAddOnLoaded(indexOrName)`](#c_addonsisaddonloadedindexorname)
   - [`C_AddOns.GetAddOnSecurity(indexOrName)`](#c_addonsgetaddonsecurityindexorname)
   - [`C_AddOns.DoesAddOnExist(indexOrName)`](#c_addonsdoesaddonexistindexorname)
 
@@ -565,6 +566,29 @@ C_AddOns.IsAddOnLoadable("HardcoreTooltips")  -- false, "DISABLED"
 C_AddOns.IsAddOnLoadable("garbage")           -- false, nil
 ```
 
+### `C_AddOns.IsAddOnLoaded(indexOrName)`
+
+Returns `loadedOrLoading, loaded` — two booleans.
+
+```lua
+C_AddOns.IsAddOnLoaded("DebugTools")    -- true, true
+C_AddOns.IsAddOnLoaded("garbage")       -- false, false
+C_AddOns.IsAddOnLoaded(1)               -- true, true   (first addon by index)
+```
+
+Modern WoW splits the two returns to distinguish "load-in-progress"
+from "fully loaded" — the difference matters for `LoadOnDemand`
+addons whose load is split across multiple `LoadAddOn` callbacks.
+Vanilla 1.12's addon loader (`FUN_0051F240`) is fully synchronous:
+the `loaded` byte flips inside a single call, so the in-flight
+state is never observable from Lua. Both returns are always the
+same boolean here. We surface the two-return shape so consumer
+code written against modern API doesn't need to special-case
+vanilla.
+
+Unknown addons (numeric index past `GetNumAddOns()`, or
+string name not in the registry) return `false, false`.
+
 ### `C_AddOns.GetAddOnSecurity(indexOrName)`
 
 Returns an `Enum.AddOnSecurityStatus` integer (not a string — modern

src/Offsets.h

@@ -2609,9 +2609,11 @@ enum Offsets {
     // We dispatch to these directly so the wrappers don't need to
     // bounce through `Script_GetAddOnInfo` and unwind 7 returns.
     //
-    //   IS_LOAD_ON_DEMAND `__fastcall(entry) → byte`
-    //     Hash-table lookup in the addon registry. Non-zero ⇒
-    //     `## LoadOnDemand: 1` in the .toc.
+    //   IS_LOADED `__fastcall(entry) → byte`
+    //     Hash-table lookup in the addon registry. Returns the byte
+    //     at `entry+0x18`, which the addon loader (`FUN_0051F240`)
+    //     writes `1` to when the addon has finished loading. Non-zero
+    //     ⇒ the addon is loaded.
     //
     //   CAN_LOAD `__fastcall(entry, char fullCheck=1, int *outStatus,
     //                        int *outDepHandle, const char *accountName) → byte`
@@ -2632,7 +2634,7 @@ enum Offsets {
     //     Hash-table lookup that returns the security category index
     //     (0=SECURE, 1=INSECURE, 2=BANNED). Defaults to `1` (INSECURE)
     //     when the entry isn't in the override table.
-    FUN_ADDON_IS_LOAD_ON_DEMAND = 0x0051E6F0,
+    FUN_ADDON_IS_LOADED = 0x0051E6F0,
     FUN_ADDON_CAN_LOAD = 0x0051E780,
     FUN_ADDON_GET_SECURITY_INDEX = 0x0051E990,
 

src/addons/Info.cpp

@@ -163,9 +163,13 @@ int __fastcall Script_IsAddOnLoadable(void *L) {
         return 2;
     }
 
-    auto isLoD = reinterpret_cast<EntryByteFn_t>(
-        Offsets::FUN_ADDON_IS_LOAD_ON_DEMAND);
-    if (isLoD(entry) != 0) {
+    // Already-loaded addons are trivially loadable — skip the
+    // recursive dep walk and return (true, nil) directly. `IS_LOADED`
+    // reads the byte at `entry+0x18` (the loader sets that to 1 on
+    // successful load).
+    auto isLoaded = reinterpret_cast<EntryByteFn_t>(
+        Offsets::FUN_ADDON_IS_LOADED);
+    if (isLoaded(entry) != 0) {
         Game::Lua::PushBoolean(L, 1);
         Game::Lua::PushNil(L);
         return 2;
@@ -229,6 +233,36 @@ int __fastcall Script_GetAddOnSecurity(void *L) {
     return 1;
 }
 
+// `C_AddOns.IsAddOnLoaded(indexOrName)` → `(loadedOrLoading, loaded)`.
+//
+// Modern WoW distinguishes "load-in-progress" from "fully loaded" —
+// matters for LoD addons whose load is split across multiple
+// `LoadAddOn` callbacks. Vanilla 1.12's `FUN_0051F240` is fully
+// synchronous: the loaded byte at `entry+0x18` flips from 0 → 1
+// inside a single call, so the "loading" state is never observable
+// from Lua. We return the same boolean twice — `loadedOrLoading`
+// and `loaded` are identical here.
+//
+// Resolves both numeric indices (via `FUN_ADDON_GET_BY_INDEX`) and
+// string names. `IS_LOADED` accepts an entry pointer as its name arg
+// because the entry's first 12 bytes are the inline NUL-terminated
+// directory name (same as the other per-field accessors), so we can
+// feed it either an entry or a Lua-side string transparently.
+int __fastcall Script_IsAddOnLoaded(void *L) {
+    const uint8_t *entry = ResolveAddOnName(L);
+    if (entry == nullptr) {
+        Game::Lua::PushBool(L, false);
+        Game::Lua::PushBool(L, false);
+        return 2;
+    }
+    auto isLoaded = reinterpret_cast<EntryByteFn_t>(
+        Offsets::FUN_ADDON_IS_LOADED);
+    const bool loaded = isLoaded(entry) != 0;
+    Game::Lua::PushBool(L, loaded);
+    Game::Lua::PushBool(L, loaded);
+    return 2;
+}
+
 // `C_AddOns.DoesAddOnExist(indexOrName)` — true iff the engine's
 // addon registry has a matching entry. For numeric input we trust
 // `GetByIndex`'s OOR-NULL; for string input we walk the flat array,
@@ -276,6 +310,8 @@ static void RegisterLuaFunctions() {
                                      &Script_GetAddOnSecurity);
     Game::Lua::RegisterTableFunction("C_AddOns", "DoesAddOnExist",
                                      &Script_DoesAddOnExist);
+    Game::Lua::RegisterTableFunction("C_AddOns", "IsAddOnLoaded",
+                                     &Script_IsAddOnLoaded);
     Game::Lua::RegisterIntegerEnum(
         "Enum", "AddOnSecurityStatus",
         kAddOnSecurityStatusEntries,