14 KiB
XCUI Editor Agent Guide
This file documents the current editor architecture for agents working under
editor/. It describes the code that exists in this checkout, not a desired
future shape.
If this file conflicts with the current code, editor/CMakeLists.txt, or the
real directory tree, trust the code and update this file in the same change.
Build Shape
The important production targets are:
XCUIEditorLib: reusable XCEditor framework code fromeditor/srcandeditor/include/XCEditor, including the reusable window authority, synchronization planner, and presentation projection underXCEditor/Windowing.XCUIEditorAppWindowing: app-internal static library for the current host contracts, content controllers, coordinators, frame transfer flow, runtime controllers, and window manager.XCUIEditorApp: concrete editor executable. Its output name isXCEngine.
Do not invent target boundaries that are not present in editor/CMakeLists.txt.
Names such as XCUIEditorAppCore, XCUIEditorAppLib, and XCUIEditorHost
are not current production library boundaries in this checkout.
There is now a narrow public editor/include/XCEditor/Windowing layer for the
generic window authority model, synchronization plan/planner, and presentation
projection. App-specific window orchestration remains under
editor/app/Windowing, and the concrete Win32 host remains under
editor/app/Platform/Win32.
Layering
Use these ownership boundaries when changing code:
editor/include/XCEditorandeditor/src: reusable editor framework. Keep this layer independent from app state, Win32, D3D12 host code, andApp::*types.editor/include/XCEditor/Windowingandeditor/src/Windowing: reusable window authority, validation, synchronization planning, commit, and presentation projection. Keep this layer generic and free of app content, host runtime, native platform, and rendering details.editor/app/Composition,Commands,Features,Project,Scene,State,System,UtilityWindows: editor product semantics.editor/app/Windowing/Content,Coordinator,Frame,Host,Runtime: app window orchestration, content ownership, frame driving, frame transfer, and per-window runtime state.editor/app/Platform/Win32: native window, message dispatch, input, lifecycle, chrome, HWND ownership, and native host adapter behavior.editor/app/Rendering: editor rendering host and D3D12 integration.
The semantic dependency direction should remain:
XCEditor framework
<- editor app semantics
<- app windowing runtime
<- Win32 host / rendering host
Startup Flow
The application starts through:
app/main.cpp
-> RunXCUIEditorApp
-> Application::Run
-> Application::Initialize
The primary workspace window is initialized through:
EditorContext::BuildWorkspaceController()
-> EditorWindowSystem::BootstrapPrimaryWindow(...)
-> EditorWindowManager::CreateWorkspaceWindow(...)
-> EditorWindowContentFactory::CreateWorkspaceContentController(...)
-> EditorWindowRuntimeController(EditorContext, contentController)
-> EditorWindowHostRuntime::CreateHostWindow(runtimeController, ...)
Keep authoritative window bootstrap in EditorWindowSystem; do not move it
back into the Win32 host.
Frame Runtime Ownership
EditorWindowManager owns steady-state frame iteration and the immediate-frame
callbacks used by native paint, resize, maximize/restore, and chrome actions.
The Win32 host may request a frame through EditorWindowHostCoordinator, but it
must not own the editor frame loop or fetch EditorContext.
EditorWindowRuntimeController lives under editor/app/Windowing/Runtime.
App windowing creates it from EditorContext plus a workspace or utility
content controller, then passes it to the native host. The Win32 host stores and
calls the runtime controller, but it does not create content controllers and it
does not receive EditorContext.
The host contract direction is:
EditorWindowManager / coordinators
-> create EditorWindowRuntimeController
-> EditorWindowHostRuntime::CreateHostWindow(runtimeController, ...)
-> Win32 EditorWindow owns HWND and delegates frame work to the runtime
Window Authority Model
EditorWindowSystem owns the authoritative UIEditorWindowWorkspaceSet through
EditorWindowWorkspaceStore.
Normal per-frame workspace edits now use direct writes into that authoritative state:
EditorWorkspaceWindowContentController::UpdateAndAppend(...)
-> EditorWindowSystem::TryBuildLiveWindowWorkspaceController(windowId, ...)
-> UIEditorWorkspaceController::BindToState(...)
-> workspace operations mutate the bound authoritative workspace/session
The old normal path is obsolete:
snapshot diff
-> workspaceMutation frame request
-> coordinator
-> synchronization plan
-> commit
Do not reintroduce workspaceMutation as the steady-state route for ordinary
layout, tab, visibility, or active-panel edits inside an existing workspace
window.
Cross-window create, update, close, and destroyed-window reconciliation still use the planner/coordinator flow:
target UIEditorWindowWorkspaceSet
-> EditorWindowSystem::BuildPlanForWindowSet(...)
-> EditorWindowWorkspaceCoordinator::ApplySynchronizationPlan(...)
-> EditorWindowSystem::CommitSynchronizationPlan(...)
EditorWindowWorkspaceCoordinator::RefreshWindowPresentation(...) refreshes
each workspace window projection from authoritative state. Presentation should
follow authority; it should not become a second source of truth.
Frame Transfer Requests
EditorWindowFrameTransferRequests is only for host-side or cross-window side
effects that cannot be represented as direct in-window workspace edits.
Current request fields are:
workspace.beginGlobalTabDragworkspace.detachPanelutility.openUtilityWindow
There is no workspace.workspaceMutation field in the current frame transfer
contract. Treat any doc, comment, or test name that says otherwise as stale.
Window Categories
Workspace and utility windows share the native host path but use distinct content controllers.
- Workspace windows use
EditorWorkspaceWindowContentController. - Utility windows use
EditorUtilityWindowContentController. - App windowing creates content through
EditorWindowContentFactory. - App windowing wraps content in
EditorWindowRuntimeController. - The concrete host validates
EditorWindowContentCapabilitiesthrough the runtime controller when a native host window is created.
Utility windows are descriptor driven through EditorUtilityWindowDescriptor,
EditorUtilityWindowRegistry, and CreateEditorUtilityWindowPanel(...).
Register new utility windows there rather than hard-coding them in Win32 host
logic.
Modification Rules
- First decide whether the change belongs to XCEditor framework, app semantics, app windowing, Win32 host, or rendering host.
- Keep public framework headers free of
App::*, Win32, and D3D12 host types. - Do not add
editor/appas an include directory forXCUIEditorLib. App-only services must cross into framework code through framework-owned interfaces and app-side adapters. - Do not compile
${XCUI_EDITOR_SHARED_SOURCES}directly intoXCUIEditorApp; the executable should consume shared framework code throughXCUIEditorLib. - Use
editor/include/XCEditor/Windowingandeditor/src/Windowingfor generic window authority, synchronization, validation, and presentation projection. - Use
editor/app/Windowingfor app-specific window runtime semantics, content, frame transfer, host contracts, runtime controllers, and coordinators. - Use
editor/app/Platform/Win32only for native host behavior and message integration. Win32 code may request frames through the host coordinator; it must not own the editor frame loop or exposeEditorContext. - Do not let
editor/app/WindowingincludePlatform/Win32headers. - Keep concrete rendering details inside
editor/app/Windowing/Runtimeoreditor/app/Rendering; do not spread D3D12 host types into content, coordinator, frame-transfer, or public host-contract headers. - Do not let Win32 host code create workspace or utility content directly.
It should receive an
EditorWindowRuntimeControllercreated by app windowing. - Use direct authoritative workspace binding for ordinary in-window workspace mutations.
- Use synchronization plans for operations that create, close, replace, or reconcile workspace windows.
- Use frame transfer requests only for host-side or cross-window effects.
Current Architecture Debt
The highest-value windowing boundary has been hardened: XCUIEditorLib now
owns the reusable window authority, synchronization planner, workspace store,
and presentation projection under XCEditor/Windowing. XCUIEditorAppWindowing
owns the app-internal content controller factory, runtime controllers,
coordinators, frame transfer flow, host contracts, and manager. The Win32 host
is the concrete native adapter and creates native host windows from runtime
controllers supplied by app windowing.
The framework/app compile boundary is also enforced. XCUIEditorLib does not
receive editor/app includes, and XCUIEditorApp does not directly compile
the shared framework sources. When framework UI code needs app-provided data
such as loaded icons, expose a framework-owned interface and adapt it in app
composition code.
The main windowing debt that was previously in the Win32 host has been cut:
frame iteration, immediate frame driving, content-controller construction, and
EditorContext ownership now live in app windowing. EditorWindowHostCoordinator
does not expose GetEditorContext(), and the native host receives an
EditorWindowRuntimeController rather than raw workspace/utility content.
The remaining promotion debt is the app runtime surface itself.
XCUIEditorAppWindowing is still app-internal and may depend on app semantics
such as EditorContext, EditorShellRuntime, utility window descriptors,
product-specific content, and the current D3D12 window render loop. Do not
promote host interfaces, frame transfer, runtime controllers, or content
controllers to XCEditor until they are generic enough to expose. Do not move
frame ownership back into editor/app/Platform/Win32.
Validation
Default editor validation is only the app build plus the 12-second smoke run:
cmake --build build --config Debug --target editor_ui_smoke_targets
build\tests\UI\Editor\smoke\Debug\editor_ui_smoke_runner.exe build\editor\Debug\XCEngine.exe
Do not run editor_windowing_phase1_tests, editor_ui_tests, or broader test
targets by default. Run them only when the user explicitly asks for them or a
separate targeted change makes them necessary.
The runner sets XCUIEDITOR_SMOKE_TEST_DURATION_SECONDS=12, waits for the
editor to launch, lets the app auto-exit, and treats a clean editor exit as
success.
Recommended Reading
Start with these files for editor/windowing work:
editor/CMakeLists.txteditor/app/Bootstrap/Application.*editor/app/Composition/EditorContext.*editor/app/Composition/EditorShellRuntime.*editor/include/XCEditor/Workspace/UIEditorWorkspaceController.heditor/src/Workspace/UIEditorWorkspaceController.cppeditor/include/XCEditor/Windowing/System/EditorWindowSystem.heditor/include/XCEditor/Windowing/System/EditorWindowSynchronizationPlan.heditor/include/XCEditor/Windowing/System/EditorWindowSynchronizationPlanner.heditor/include/XCEditor/Windowing/Presentation/EditorWorkspaceWindowProjection.heditor/include/XCEditor/Windowing/Presentation/EditorWindowPresentationPolicy.heditor/src/Windowing/System/EditorWindowSystem.cppeditor/src/Windowing/System/EditorWindowWorkspaceStore.*editor/src/Windowing/System/EditorWindowSynchronizationPlanner.cppeditor/src/Windowing/Presentation/EditorWindowPresentationPolicy.cppeditor/app/Windowing/Host/EditorWindowHostInterfaces.heditor/app/Windowing/Content/EditorWindowContentController.heditor/app/Windowing/Content/EditorWindowContentFactory.*editor/app/Windowing/Content/EditorWorkspaceWindowContentController.*editor/app/Windowing/Frame/EditorWindowFrameOrchestrator.*editor/app/Windowing/Frame/EditorWindowTransferRequests.heditor/app/Windowing/Runtime/EditorWindowRuntimeController.*editor/app/Windowing/Runtime/EditorWindowScreenshotController.*editor/app/Windowing/Coordinator/EditorWindowWorkspaceCoordinator.*editor/app/Windowing/Coordinator/EditorUtilityWindowCoordinator.*editor/app/Windowing/EditorWindowManager.*editor/app/Platform/Win32/Windowing/EditorWindow.*editor/app/Platform/Win32/Windowing/EditorWindowHostRuntime.*editor/app/Platform/Win32/Windowing/EditorWindowMessageDispatcher.*tests/UI/Editor/smoke/CMakeLists.txt
Recent Cuts
- The framework-to-app icon dependency is sealed:
UIEditorShellComposeuses the framework-ownedUIEditorShellIconResolver, and the app adaptsBuiltInIconsinEditorShellDrawComposer. - The framework/app compile boundary is sealed:
XCUIEditorLibdoes not receiveeditor/appincludes,XCUIEditorAppdoes not directly compile${XCUI_EDITOR_SHARED_SOURCES}, and the app consumes framework code throughXCUIEditorLib. - The reusable window authority core lives in the framework:
EditorWindowSystem, synchronization planning, workspace store, and presentation projection are undereditor/include/XCEditor/Windowingandeditor/src/Windowing. - App windowing owns the runtime cut: content controllers,
EditorWindowRuntimeController, frame driving, frame transfer, host contracts, andEditorWindowManagerare undereditor/app/Windowing; Win32 remains the native adapter and no longer exposesEditorContext. - Default validation remains the editor app build plus the 12-second smoke run; run broader windowing/unit targets only for targeted coverage.