feat(frame): add GetClickFrame global

Backport the engine-registered C global behind the /click command: resolve
a frame by its global name, returning it only when _G[name] holds a real
frame whose GetName() matches. Mirrors 3.3.5's Script_GetClickFrame; reads
the name from CFrameScriptObject vtable slot +4, verified against 1.12's
own Script_GetName.

Author: brues-code

README.md

@@ -67,7 +67,7 @@ reference in **[docs/API.md](docs/API.md)**.
 | [Expansion](docs/API.md#expansion) | `ClassicExpansionAtLeast`, `ClassicExpansionAtMost`, `GetClassicExpansionLevel` |
 | [Faction](docs/API.md#faction) | `C_Reputation.GetFactionDataByIndex`, `C_Reputation.GetFactionStandings`, `C_Reputation.GetLastStandingChange`, `C_Reputation.GetWatchedFactionData`, `C_Reputation.SetWatchedFactionByID`, `GetFactionIDByIndex`, `GetFactionInfoByID`, `GetFactionParentID` |
 | [Focus](docs/API.md#focus) | `ClearFocus`, `FocusUnit` |
-| [Frame](docs/API.md#frame) | `region:SetPoint("point")` (one-arg form), `region:SetSize`, `region:GetSize`, `region:IsMouseOver`, `region:GetRect`, `region:IsDragging`, `GetMouseFoci`, `frame:SetShown`, `fontstring:GetStringHeight`, `fontstring:GetUnboundedStringWidth`, `fontstring:GetWrappedWidth`, `fontstring:GetNumLines`, `fontstring:GetLineHeight`, `fontstring:IsTruncated`, `fontstring:SetMaxLines`, `fontstring:GetMaxLines`, `fontstring:SetFormattedText`, `texture:SetRotation`, `texture:GetRotation`, `texture:SetVertexOffset`, `texture:GetVertexOffset`, `texture:SetColorTexture`, `texture:SetMask`, `frame:CreateMaskTexture`, `texture:AddMaskTexture`, `texture:RemoveMaskTexture`, `texture:GetNumMaskTextures`, `texture:GetMaskTexture`, `fontstring:SetRotation`, `fontstring:GetRotation`, `frame:SetResizeBounds`, `frame:HookScript`, `frame:IsEventRegistered`, `frame:GetEffectiveAlpha`, `frame:SetAttribute`, `frame:SetAttributeNoHandler`, `frame:ClearAttribute`, `frame:GetAttribute`, `OnAttributeChanged` (script), `SetModernScriptArgs`, `GetModernScriptArgs`, `SecureCmdOptionParse`, `RegisterStateDriver`, `UnregisterStateDriver`, `RegisterAttributeDriver`, `UnregisterAttributeDriver`, `RegisterUnitWatch`, `UnregisterUnitWatch`, `UnitWatchRegistered`, `SecureButton_GetAttribute`, `SecureButton_GetUnit`, `PreClick` (script), `PostClick` (script) |
+| [Frame](docs/API.md#frame) | `region:SetPoint("point")` (one-arg form), `region:SetSize`, `region:GetSize`, `region:IsMouseOver`, `region:GetRect`, `region:IsDragging`, `GetMouseFoci`, `frame:SetShown`, `fontstring:GetStringHeight`, `fontstring:GetUnboundedStringWidth`, `fontstring:GetWrappedWidth`, `fontstring:GetNumLines`, `fontstring:GetLineHeight`, `fontstring:IsTruncated`, `fontstring:SetMaxLines`, `fontstring:GetMaxLines`, `fontstring:SetFormattedText`, `texture:SetRotation`, `texture:GetRotation`, `texture:SetVertexOffset`, `texture:GetVertexOffset`, `texture:SetColorTexture`, `texture:SetMask`, `frame:CreateMaskTexture`, `texture:AddMaskTexture`, `texture:RemoveMaskTexture`, `texture:GetNumMaskTextures`, `texture:GetMaskTexture`, `fontstring:SetRotation`, `fontstring:GetRotation`, `frame:SetResizeBounds`, `frame:HookScript`, `frame:IsEventRegistered`, `frame:GetEffectiveAlpha`, `frame:SetAttribute`, `frame:SetAttributeNoHandler`, `frame:ClearAttribute`, `frame:GetAttribute`, `OnAttributeChanged` (script), `SetModernScriptArgs`, `GetModernScriptArgs`, `SecureCmdOptionParse`, `RegisterStateDriver`, `UnregisterStateDriver`, `RegisterAttributeDriver`, `UnregisterAttributeDriver`, `RegisterUnitWatch`, `UnregisterUnitWatch`, `UnitWatchRegistered`, `SecureButton_GetAttribute`, `SecureButton_GetUnit`, `PreClick` (script), `PostClick` (script), `GetClickFrame` |
 | [FriendList](docs/API.md#friendlist) | `C_FriendList.GetFriendInfo`, `C_FriendList.GetFriendInfoByIndex`, `C_FriendList.GetNumFriends`, `C_FriendList.GetNumOnlineFriends`, `C_FriendList.GetNumWhoResults`, `C_FriendList.GetWhoInfo`, `C_FriendList.IsFriend`, `C_FriendList.IsIgnored`, `C_FriendList.IsIgnoredByGuid`, `C_FriendList.IsWhoQueryPending`, `C_FriendList.SendWhoQueryByName`, `C_FriendList.SetFriendNotes`, `C_FriendList.SetFriendNotesByIndex` |
 | [GameObject](docs/API.md#gameobject) | `C_GameObjectInfo.GetGameObjectInfoByID`, `C_GameObjectInfo.RequestLoadGameObjectByID`, `ClosestGameObjectPosition` |
 | [Glue](docs/API.md#glue) | `C_Glue.IsOnGlueScreen` |

docs/API.md

@@ -204,6 +204,7 @@ build instructions.
   - [`RegisterUnitWatch` / `UnregisterUnitWatch` / `UnitWatchRegistered`](#registerunitwatch--unregisterunitwatch--unitwatchregistered)
   - [`SecureButton_GetAttribute` / `SecureButton_GetUnit`](#securebutton_getattribute--securebutton_getunit)
   - [`PreClick` / `PostClick` button scripts](#preclick--postclick-button-scripts)
+  - [`GetClickFrame(name)`](#getclickframename)
 
 - [FriendList](#friendlist)
   - [`C_FriendList.SendWhoQueryByName(name)`](#c_friendlistsendwhoquerybynamename)
@@ -4995,6 +4996,21 @@ the normal use: run code just before or after a button's click action. (Modern
 WoW fires them even with no `OnClick`; that path is not available on this
 client.)
 
+### `GetClickFrame(name)`
+
+Returns the frame with the given global name. The `/click` command uses it to
+change a frame name into the frame.
+
+The function returns the frame only when `_G[name]` holds a real frame, and the
+`GetName()` of that frame is equal to `name`. If the global holds a different
+value, a plain table, or a frame with a different name, the function returns
+nil. This name test makes sure that a changed global does not return the wrong
+frame.
+
+```lua
+GetClickFrame("MyButton")     -- the frame named "MyButton", or nil
+```
+
 ## FriendList
 
 ### `C_FriendList.SendWhoQueryByName(name)`

src/frame/ClickFrame.cpp

@@ -0,0 +1,99 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software Foundation, either
+// version 3 of the License, or (at your option) any later version.
+//
+// ClassicAPI is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+// PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// `GetClickFrame(name)` — backport of the C global WoW registers for the
+// `/click` handler to resolve a frame by its global name. Vanilla 1.12
+// never shipped it; 3.3.5's `Script_GetClickFrame` (`0x00564130`) is the
+// reference.
+//
+// It lives in the DLL, not addon Lua, because Blizzard shipped it as an
+// engine-registered C global — the backport mirrors where the real
+// function lives, not the fact that Lua could fake it.
+//
+// Behaviour, matching the 3.3.5 resolver `FUN_00562990` (minus its private
+// name→frame memoization cache, which is only a perf optimization over the
+// global lookup):
+//   1. `_G[name]` — a plain global-table lookup.
+//   2. The value must be a frame wrapper table backed by a
+//      `CFrameScriptObject`.
+//   3. Its real `GetName()` must equal `name`. This is the load-bearing
+//      check: it stops a reassigned global (`_G["Foo"] = someOtherFrame`)
+//      from resolving to a differently-named frame.
+// Return the frame on a match, otherwise nil.
+//
+// `GetName()` is the object's vtable slot +4 (`__thiscall`, returns
+// `const char *`) — verified from 1.12's own `Script_GetName`
+// (`0x0079FF60` / `0x007A1390`), which resolves self the same way and reads
+// the name from that slot. It's a base virtual present on every
+// `CFrameScriptObject` subtype, so calling it after `ResolveObject` is
+// safe without the RTTI subtype gate `Script_GetName` does first.
+
+#include "Game.h"
+#include "Offsets.h"
+
+#include <cstring>
+
+namespace Frame::ClickFrame {
+
+namespace {
+// CFrameScriptObject::GetName — vtable slot +4, thiscall, no args.
+using GetName_t = const char *(__thiscall *)(void *self);
+
+const char *ObjectName(void *obj) {
+    auto vtable = *reinterpret_cast<void ***>(obj);
+    auto getName = reinterpret_cast<GetName_t>(vtable[1]);
+    return getName(obj);
+}
+} // namespace
+
+static int __fastcall Script_GetClickFrame(void *L) {
+    using namespace Game::Lua;
+
+    if (GetTop(L) < 1) {
+        Error(L, "Usage: GetClickFrame(\"name\")");
+        return 0;
+    }
+    const char *name = ToString(L, 1);
+    if (name == nullptr) {
+        PushNil(L);
+        return 1;
+    }
+
+    // getglobal(name): push _G[name].
+    PushString(L, name);
+    GetTable(L, GLOBALS_INDEX);
+
+    if (Type(L, -1) != TYPE_TABLE) {
+        PushNil(L);
+        return 1;
+    }
+
+    void *obj = ResolveObject(L, -1);
+    if (obj != nullptr) {
+        const char *objName = ObjectName(obj);
+        if (objName != nullptr && std::strcmp(objName, name) == 0)
+            // The wrapper table is still on top — return it as-is.
+            return 1;
+    }
+
+    PushNil(L);
+    return 1;
+}
+
+static void RegisterLuaFunctions() {
+    Game::Lua::RegisterGlobalFunction("GetClickFrame", &Script_GetClickFrame);
+}
+
+static const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
+
+} // namespace Frame::ClickFrame