eden-cli: set the window title from the main thread

The titlebar timer runs on SDL's timer thread, and on macOS AppKit throws
when a window title is set from there, aborting eden-cli two seconds in.
The timer now only prepares the title; the main loop applies it.

Assisted-by: Claude Opus 5.5 (code changes, debugging and commit message)

3 files changed, 21 insertions, 2 deletions

diff --git a/src/yuzu_cmd/emu_window/emu_window_sdl3.cpp b/src/yuzu_cmd/emu_window/emu_window_sdl3.cpp
index ecb8171ac7..93bbbfb8fc 100644
--- a/src/yuzu_cmd/emu_window/emu_window_sdl3.cpp
+++ b/src/yuzu_cmd/emu_window/emu_window_sdl3.cpp
@@ -38,8 +38,10 @@ EmuWindow_SDL3::EmuWindow_SDL3(InputCommon::InputSubsystem* input_subsystem_, Co
     titlebar_timer = SDL_AddTimer(2000, [](void *userdata, SDL_TimerID, Uint32) -> Uint32 {
         auto* this_ = (EmuWindow_SDL3*)userdata;
         auto const results = this_->system.GetAndResetPerfStats();
-        auto const title = fmt::format("{} | {}-{} | FPS: {:.0f} ({:.0f}%)", Common::g_build_fullname, Common::g_scm_branch, Common::g_scm_desc, results.average_game_fps, results.emulation_speed * 100.0f);
-        SDL_SetWindowTitle(this_->render_window, title.c_str());
+        auto* const title = new std::string(fmt::format("{} | {}-{} | FPS: {:.0f} ({:.0f}%)", Common::g_build_fullname, Common::g_scm_branch, Common::g_scm_desc, results.average_game_fps, results.emulation_speed * 100.0f));
+        // Timers run on their own thread and AppKit throws when a title is set off the main
+        // thread: ApplyPendingTitle sets it from the main loop.
+        delete this_->pending_title.exchange(title);
         return 2000;
     }, this);
     mouse_timer = SDL_AddTimer(100, [](void *userdata, SDL_TimerID, Uint32) -> Uint32 {
@@ -55,6 +57,7 @@ EmuWindow_SDL3::EmuWindow_SDL3(InputCommon::InputSubsystem* input_subsystem_, Co
 EmuWindow_SDL3::~EmuWindow_SDL3() {
     SDL_RemoveTimer(titlebar_timer);
     SDL_RemoveTimer(mouse_timer);
+    delete pending_title.exchange(nullptr);
     system.HIDCore().UnloadInputDevices();
     input_subsystem->Shutdown();
     SDL_Quit();
@@ -154,6 +157,13 @@ bool EmuWindow_SDL3::IsOpen() const {
     return is_open;
 }
 
+void EmuWindow_SDL3::ApplyPendingTitle() {
+    if (std::string* const title = pending_title.exchange(nullptr)) {
+        SDL_SetWindowTitle(render_window, title->c_str());
+        delete title;
+    }
+}
+
 bool EmuWindow_SDL3::IsShown() const {
     return is_shown;
 }
diff --git a/src/yuzu_cmd/emu_window/emu_window_sdl3.h b/src/yuzu_cmd/emu_window/emu_window_sdl3.h
index 0dc2a4983a..a76a2bfd85 100644
--- a/src/yuzu_cmd/emu_window/emu_window_sdl3.h
+++ b/src/yuzu_cmd/emu_window/emu_window_sdl3.h
@@ -6,7 +6,9 @@
 
 #pragma once
 
+#include <atomic>
 #include <cstdlib>
+#include <string>
 #include <tuple>
 #include <utility>
 
@@ -41,6 +43,9 @@ public:
     /// Whether the window is still open, and a close request hasn't yet been sent
     bool IsOpen() const;
 
+    /// Sets the title the titlebar timer prepared; call from the main thread.
+    void ApplyPendingTitle();
+
     /// Returns if window is shown (not minimized)
     bool IsShown() const override;
 
@@ -92,6 +97,7 @@ protected:
 
     /// Periodic changer of titlebar (independent of event loop)
     SDL_TimerID titlebar_timer;
+    std::atomic<std::string*> pending_title{};
 
     // Mouse resetter once it
     SDL_TimerID mouse_timer;
diff --git a/src/yuzu_cmd/yuzu.cpp b/src/yuzu_cmd/yuzu.cpp
index 22abe6a759..4d71a29993 100644
--- a/src/yuzu_cmd/yuzu.cpp
+++ b/src/yuzu_cmd/yuzu.cpp
@@ -481,6 +481,9 @@ static void RunKeyScript(InputCommon::InputSubsystem& input_subsystem) {
 extern "C" SDL_AppResult SDL_AppIterate(void *appstate) {
     SdlState *state = (SdlState *)appstate;
     RunKeyScript(state->input_subsystem);
+    if (state->emu_window) {
+        state->emu_window->ApplyPendingTitle();
+    }
     return state->emu_window && state->emu_window->IsOpen() ? SDL_APP_CONTINUE : SDL_APP_SUCCESS;
 }
 extern "C" SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event) {