fix: running installed copies are renamed aside, not deleted under their name at restart

Turning boot-apply off while the tray app runs, then on again before a
restart, scheduled the new copy's deletion. Installing over a running
copy failed outright. Both now rename the running file aside first.
Also: the tray's stock-by-choice notice is no longer accepted from
unelevated processes and is only sent after a successful reset, and
the tuning lock waits briefly so the watchdog's look cannot refuse
an optimize.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: Rovey

src/app/common.cpp

@@ -24,7 +24,8 @@ constexpr wchar_t kTrayWindowClass[] = L"GpuAutoOptimizerWindow";
 TuningLock::TuningLock() {
     handle_ = CreateMutexW(nullptr, FALSE, kTuningMutex);
     if (!handle_) return;
-    const DWORD r = WaitForSingleObject(handle_, 0);
+    // Not 0: tuning_in_progress() holds the mutex for an instant while it looks.
+    const DWORD r = WaitForSingleObject(handle_, 100);
     owned_ = r == WAIT_OBJECT_0 || r == WAIT_ABANDONED;   // abandoned: the last owner died mid-run
 }
 

src/app/gui/main_gui.cpp

@@ -538,11 +538,13 @@ int WINAPI wWinMain(HINSTANCE inst, HINSTANCE, PWSTR cmdline, int) {
     const BOOL dark = TRUE;   // a dark title bar to match the dark window
     DwmSetWindowAttribute(g.hwnd, DWMWA_USE_IMMERSIVE_DARK_MODE, &dark, sizeof(dark));
 
-    // Explorer runs unelevated; let its tray notifications, a relaunch's
-    // "come forward" and gao --reset's notice reach an elevated window.
+    // Explorer runs unelevated; let its tray notifications and a relaunch's
+    // "come forward" reach an elevated window. Not the stock-by-choice notice:
+    // gao --reset is always elevated, and an unelevated process must not be
+    // able to switch the watchdog off.
     g.taskbar_created = RegisterWindowMessageW(L"TaskbarCreated");
     g.stock_by_choice = gao::app::stock_by_choice_message();
-    for (UINT m : {WM_APP_TRAY, g.taskbar_created, WM_APP_SHOW, g.stock_by_choice})
+    for (UINT m : {WM_APP_TRAY, g.taskbar_created, WM_APP_SHOW})
         ChangeWindowMessageFilterEx(g.hwnd, m, MSGFLT_ALLOW, nullptr);
 
     IMGUI_CHECKVERSION();

src/app/main.cpp

@@ -114,7 +114,7 @@ static int reset() {
         ok = ok && power_ok;
     }
     // A stock card by choice: a running tray app must not re-apply the tune.
-    gao::app::tell_tray_stock_by_choice();
+    if (ok) gao::app::tell_tray_stock_by_choice();
     std::printf("%s\n", ok ? "OK" : "MISMATCH");
     return ok ? 0 : 1;
 }

src/hw/boot_task.cpp

@@ -40,6 +40,19 @@ std::filesystem::path installed_dir() {
 std::filesystem::path installed_exe_path() { return installed_dir() / L"gao.exe"; }
 std::filesystem::path installed_tray_path() { return installed_dir() / L"GpuAutoOptimizer.exe"; }
 
+namespace {
+// A running exe cannot be deleted or overwritten, but it can be renamed.
+// Moving it aside frees its name at once; the renamed file goes at the next
+// restart. (Deleting it under its own name at restart would also delete a
+// copy installed there in the meantime.)
+bool move_aside(const std::filesystem::path& p) {
+    const auto aside = std::filesystem::path(p).concat(L".old-" + std::to_wstring(GetTickCount64()));
+    if (!MoveFileExW(p.c_str(), aside.c_str(), 0)) return false;
+    MoveFileExW(aside.c_str(), nullptr, MOVEFILE_DELAY_UNTIL_REBOOT);
+    return true;
+}
+}
+
 bool install_app(const std::filesystem::path& from_dir, std::string* why) {
     const auto dst = installed_dir();
     if (dst.empty()) { if (why) *why = "the Program Files folder could not be resolved"; return false; }
@@ -48,7 +61,8 @@ bool install_app(const std::filesystem::path& from_dir, std::string* why) {
     std::filesystem::create_directories(dst, ec);
     for (const wchar_t* name : kAppExes) {
         const auto src = from_dir / name;
-        if (!CopyFileW(src.c_str(), (dst / name).c_str(), FALSE)) {
+        const auto to = dst / name;
+        if (!CopyFileW(src.c_str(), to.c_str(), FALSE) && !(move_aside(to) && CopyFileW(src.c_str(), to.c_str(), FALSE))) {
             if (why) *why = "could not copy " + src.string() + " to " + dst.string() + " (error " + std::to_string(GetLastError()) + ")";
             return false;
         }
@@ -63,7 +77,7 @@ bool uninstall_app() {
     for (const wchar_t* name : kAppExes) {
         const auto p = dst / name;
         if (DeleteFileW(p.c_str()) || GetLastError() == ERROR_FILE_NOT_FOUND) continue;
-        MoveFileExW(p.c_str(), nullptr, MOVEFILE_DELAY_UNTIL_REBOOT);
+        move_aside(p);
         all = false;
     }
     if (all) RemoveDirectoryW(dst.c_str());   // only succeeds when empty

src/hw/boot_task.hpp

@@ -13,11 +13,12 @@ inline constexpr const wchar_t* kAppExes[] = {L"gao.exe", L"GpuAutoOptimizer.exe
 std::filesystem::path installed_dir();        // %ProgramFiles%\GpuAutoOptimizer
 std::filesystem::path installed_exe_path();   // ...\gao.exe
 std::filesystem::path installed_tray_path();  // ...\GpuAutoOptimizer.exe
-// Copies both executables from `from_dir` into installed_dir() (overwriting);
+// Copies both executables from `from_dir` into installed_dir() (overwriting; a
+// running copy is renamed aside first);
 // a no-op when `from_dir` already is that folder.
 bool install_app(const std::filesystem::path& from_dir, std::string* why);
 // Removes both copies and, if empty, the folder. A copy that is running (the
-// tray app) is scheduled for deletion at the next restart; returns false then.
+// tray app) is renamed aside and deleted at the next restart; returns false then.
 bool uninstall_app();
 bool files_equal(const std::filesystem::path& a, const std::filesystem::path& b);