Add Toggle Hidden Files mod

[Asteski]

Toggle Hidden Files

This mod allows you to toggle the visibility of hidden files in Windows Explorer using the Ctrl+H keyboard shortcut.

Features

• Ctrl+H hotkey that works only when Explorer windows are focused
• Toggles the "Show hidden files" setting
• Optional: Also toggle protected OS files
• Automatically refreshes Explorer windows
• Works with all Windows Explorer windows

Usage

1. Focus an Explorer window - Click on or open any File Explorer window
2. Press Ctrl+H - Use the keyboard shortcut to toggle hidden files visibility
3. The setting will be applied immediately to all Explorer windows

Settings

• Also toggle protected OS files: When enabled, Ctrl+H will also show/hide protected operating system files

Technical Details

• Only activates when Windows Explorer windows are in focus
• Modifies the standard registry settings for showing hidden files
• Sends refresh messages to all Explorer windows
• Handles proper cleanup when the mod is unloaded
• Explorer process must be restarted for changes to take effect

[m417z]

Why is this compiler option needed?

[m417z]

From the documentation:

This hook is called in the context of the thread that installed it. The call is made by sending a message to the thread that installed the hook. Therefore, the thread that installed the hook must have a message loop.

Wh_ModInit is either called on the initial Explorer thread, or in a dedicated Windhawk thread. Not in all cases that thread has a message loop. To make it work in all cases, create a dedicated thread for it. Here's an example:

https://github.com/m417z/7-Taskbar-Numberer/blob/master/dll/keybd_hook.c

[m417z]

This mod has no good reason to run as part of explorer.exe, except that it's convenient. We discussed it here: #1916 (comment)

This mod is injected into explorer and runs as part of it. This is suboptimal for the following reasons:

• There can be more than one explorer.exe process in case the "launch folder windows in separate process" option is enabled, and for other reasons.
• This mod doesn't have a good reason to be injected into explorer.exe, it's just convenient. But by doing so, a mistake or instability in the mod affects the whole shell.

This is not the first mod to take this approach. Here are other recent mods:

• New MOD "edge-hot-corner-desktop-switch" #1832
• added mod auto-hide-desktop-after-inactivity.wh.cpp #1913

And maybe also:

• https://windhawk.net/mods/classic-theme-enable
• https://windhawk.net/mods/magnifier-mod

All three mods could be separate tools, they don't use and don't need Windhawk's injection and hooking capabilities. On the other hand, I can understand that the ease of mod installation is appealing. I wonder if Windhawk needs to come up with a new type of mods which run as part of a dedicated process.

Currently, Windhawk doesn't have a built-in functionality for something like that, but for now, I implemented some code that can be added to a mod to make it run as part of a separate windhawk.exe process:

Details

////////////////////////////////////////////////////////////////////////////////
// Windhawk tool mod implementation for mods which don't need to inject to other
// processes or hook other functions. Context:
// https://github.com/ramensoftware/windhawk-mods/pull/1916
//
// The mod will load and run in a dedicated windhawk.exe process.
//
// Paste the code below as part of the mod code, and use these callbacks:
// * WhTool_ModInit
// * WhTool_ModSettingsChanged
// * WhTool_ModUninit
//
// Currently, other callbacks are not supported.

bool g_isToolModProcessLauncher;
HANDLE g_toolModProcessMutex;

void WINAPI EntryPoint_Hook() {
    Wh_Log(L">");
    ExitThread(0);
}

BOOL Wh_ModInit() {
    bool isService = false;
    bool isToolModProcess = false;
    bool isCurrentToolModProcess = false;
    int argc;
    LPWSTR* argv = CommandLineToArgvW(GetCommandLine(), &argc);
    if (!argv) {
        Wh_Log(L"CommandLineToArgvW failed");
        return FALSE;
    }

    for (int i = 1; i < argc; i++) {
        if (wcscmp(argv[i], L"-service") == 0) {
            isService = true;
            break;
        }
    }

    for (int i = 1; i < argc - 1; i++) {
        if (wcscmp(argv[i], L"-tool-mod") == 0) {
            isToolModProcess = true;
            if (wcscmp(argv[i + 1], WH_MOD_ID) == 0) {
                isCurrentToolModProcess = true;
            }
            break;
        }
    }

    LocalFree(argv);

    if (isService) {
        return FALSE;
    }

    if (isCurrentToolModProcess) {
        g_toolModProcessMutex =
            CreateMutex(nullptr, TRUE, L"windhawk-tool-mod_" WH_MOD_ID);
        if (!g_toolModProcessMutex) {
            Wh_Log(L"CreateMutex failed");
            ExitProcess(1);
        }

        if (GetLastError() == ERROR_ALREADY_EXISTS) {
            Wh_Log(L"Tool mod already running (%s)", WH_MOD_ID);
            ExitProcess(1);
        }

        if (!WhTool_ModInit()) {
            ExitProcess(1);
        }

        IMAGE_DOS_HEADER* dosHeader =
            (IMAGE_DOS_HEADER*)GetModuleHandle(nullptr);
        IMAGE_NT_HEADERS* ntHeaders =
            (IMAGE_NT_HEADERS*)((BYTE*)dosHeader + dosHeader->e_lfanew);

        DWORD entryPointRVA = ntHeaders->OptionalHeader.AddressOfEntryPoint;
        void* entryPoint = (BYTE*)dosHeader + entryPointRVA;

        Wh_SetFunctionHook(entryPoint, (void*)EntryPoint_Hook, nullptr);
        return TRUE;
    }

    if (isToolModProcess) {
        return FALSE;
    }

    g_isToolModProcessLauncher = true;
    return TRUE;
}

void Wh_ModAfterInit() {
    if (!g_isToolModProcessLauncher) {
        return;
    }

    WCHAR currentProcessPath[MAX_PATH];
    switch (GetModuleFileName(nullptr, currentProcessPath,
                              ARRAYSIZE(currentProcessPath))) {
        case 0:
        case ARRAYSIZE(currentProcessPath):
            Wh_Log(L"GetModuleFileName failed");
            return;
    }

    WCHAR
    commandLine[MAX_PATH + 2 +
                (sizeof(L" -tool-mod \"" WH_MOD_ID "\"") / sizeof(WCHAR)) - 1];
    swprintf_s(commandLine, L"\"%s\" -tool-mod \"%s\"", currentProcessPath,
               WH_MOD_ID);

    HMODULE kernelModule = GetModuleHandle(L"kernelbase.dll");
    if (!kernelModule) {
        kernelModule = GetModuleHandle(L"kernel32.dll");
        if (!kernelModule) {
            Wh_Log(L"No kernelbase.dll/kernel32.dll");
            return;
        }
    }

    using CreateProcessInternalW_t = BOOL(WINAPI*)(
        HANDLE hUserToken, LPCWSTR lpApplicationName, LPWSTR lpCommandLine,
        LPSECURITY_ATTRIBUTES lpProcessAttributes,
        LPSECURITY_ATTRIBUTES lpThreadAttributes, WINBOOL bInheritHandles,
        DWORD dwCreationFlags, LPVOID lpEnvironment, LPCWSTR lpCurrentDirectory,
        LPSTARTUPINFOW lpStartupInfo,
        LPPROCESS_INFORMATION lpProcessInformation,
        PHANDLE hRestrictedUserToken);
    CreateProcessInternalW_t pCreateProcessInternalW =
        (CreateProcessInternalW_t)GetProcAddress(kernelModule,
                                                 "CreateProcessInternalW");
    if (!pCreateProcessInternalW) {
        Wh_Log(L"No CreateProcessInternalW");
        return;
    }

    STARTUPINFO si{
        .cb = sizeof(STARTUPINFO),
        .dwFlags = STARTF_FORCEOFFFEEDBACK,
    };
    PROCESS_INFORMATION pi;
    if (!pCreateProcessInternalW(nullptr, currentProcessPath, commandLine,
                                 nullptr, nullptr, FALSE, NORMAL_PRIORITY_CLASS,
                                 nullptr, nullptr, &si, &pi, nullptr)) {
        Wh_Log(L"CreateProcess failed");
        return;
    }

    CloseHandle(pi.hProcess);
    CloseHandle(pi.hThread);
}

void Wh_ModSettingsChanged() {
    if (g_isToolModProcessLauncher) {
        return;
    }

    WhTool_ModSettingsChanged();
}

void Wh_ModUninit() {
    if (g_isToolModProcessLauncher) {
        return;
    }

    WhTool_ModUninit();
    ExitProcess(0);
}

Please do the following:

• Add the code above at the end of your mod code
• Replace Wh_ModInit, Wh_ModSettingsChanged, Wh_ModUninit in your code to WhTool_*, e.g. WhTool_ModInit
• Change the target process from explorer.exe to windhawk.exe
• Remove the FindCurrentProcessTaskbarWnd check, as it's now guaranteed that only one instance will be running

Please try it and let me know if it behaves as expected in all cases. If it is, let's adapt it. In the future, such functionality might become part of Windhawk.