PowerToys/src/modules/keyboardmanager/KeyboardManagerEngineLibrary/KeyboardManager.cpp

#include "pch.h"
#include "KeyboardManager.h"
#include <interface/powertoy_module_interface.h>
#include <common/SettingsAPI/settings_objects.h>
#include <common/interop/shared_constants.h>
#include <common/debug_control.h>
#include <common/utils/winapi_error.h>
#include <common/logger/logger_settings.h>

#include <keyboardmanager/common/Shortcut.h>
#include <keyboardmanager/common/RemapShortcut.h>
#include <keyboardmanager/common/KeyboardManagerConstants.h>
#include <keyboardmanager/common/Helpers.h>
#include <keyboardmanager/common/KeyboardEventHandlers.h>
#include <ctime>

#include "KeyboardEventHandlers.h"
#include "trace.h"

HHOOK KeyboardManager::hookHandleCopy;
HHOOK KeyboardManager::hookHandle;
KeyboardManager* KeyboardManager::keyboardManagerObjectPtr;

KeyboardManager::KeyboardManager()
{
    // Load the initial settings.
    LoadSettings();

    // Set the static pointer to the newest object of the class
    keyboardManagerObjectPtr = this;

    std::filesystem::path modulePath(PTSettingsHelper::get_module_save_folder_location(moduleName));
    auto changeSettingsCallback = [this](DWORD err) {
        Logger::trace(L"{} event was signaled", KeyboardManagerConstants::SettingsEventName);
        if (err != ERROR_SUCCESS)
        {
            Logger::error(L"Failed to watch settings changes. {}", get_last_error_or_default(err));
        }

        loadingSettings = true;
        try
        {
            LoadSettings();
        }
        catch (...)
        {
            Logger::error("Failed to load settings");
        }

        loadingSettings = false;
    };

    editorIsRunningEvent = CreateEvent(nullptr, true, false, KeyboardManagerConstants::EditorWindowEventName.c_str());
    settingsEventWaiter = EventWaiter(KeyboardManagerConstants::SettingsEventName, changeSettingsCallback);
}

void KeyboardManager::LoadSettings()
{
    bool loadedSuccessful = state.LoadSettings();
    if (!loadedSuccessful)
    {
        std::this_thread::sleep_for(std::chrono::milliseconds(500));

        // retry once
        state.LoadSettings();
    }
}

LRESULT CALLBACK KeyboardManager::HookProc(int nCode, const WPARAM wParam, const LPARAM lParam)
{
    LowlevelKeyboardEvent event{};
    if (nCode == HC_ACTION)
    {
        event.lParam = reinterpret_cast<KBDLLHOOKSTRUCT*>(lParam);
        event.wParam = wParam;
        event.lParam->vkCode = Helpers::EncodeKeyNumpadOrigin(event.lParam->vkCode, event.lParam->flags & LLKHF_EXTENDED);

        if (keyboardManagerObjectPtr->HandleKeyboardHookEvent(&event) == 1)
        {
            // Reset Num Lock whenever a NumLock key down event is suppressed since Num Lock key state change occurs before it is intercepted by low level hooks
            if (event.lParam->vkCode == VK_NUMLOCK && (event.wParam == WM_KEYDOWN || event.wParam == WM_SYSKEYDOWN) && event.lParam->dwExtraInfo != KeyboardManagerConstants::KEYBOARDMANAGER_SUPPRESS_FLAG)
            {
                KeyboardEventHandlers::SetNumLockToPreviousState(keyboardManagerObjectPtr->inputHandler);
            }
            return 1;
        }
    }

    return CallNextHookEx(hookHandleCopy, nCode, wParam, lParam);
}

void KeyboardManager::StartLowlevelKeyboardHook()
{
#if defined(DISABLE_LOWLEVEL_HOOKS_WHEN_DEBUGGED)
    if (IsDebuggerPresent())
    {
        return;
    }
#endif

    if (!hookHandle)
    {
        hookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, HookProc, GetModuleHandle(NULL), NULL);
        hookHandleCopy = hookHandle;
        if (!hookHandle)
        {
            DWORD errorCode = GetLastError();
            show_last_error_message(L"SetWindowsHookEx", errorCode, L"PowerToys - Keyboard Manager");
            auto errorMessage = get_last_error_message(errorCode);
            Trace::Error(errorCode, errorMessage.has_value() ? errorMessage.value() : L"", L"StartLowlevelKeyboardHook::SetWindowsHookEx");
        }
    }
}

void KeyboardManager::StopLowlevelKeyboardHook()
{
    if (hookHandle)
    {
        UnhookWindowsHookEx(hookHandle);
        hookHandle = nullptr;
    }
}

intptr_t KeyboardManager::HandleKeyboardHookEvent(LowlevelKeyboardEvent* data) noexcept
{
    if (loadingSettings)
    {
        return 0;
    }

    // Suspend remapping if remap key/shortcut window is opened
    if (editorIsRunningEvent != nullptr && WaitForSingleObject(editorIsRunningEvent, 0) == WAIT_OBJECT_0)
    {
        return 0;
    }

    // If key has suppress flag, then suppress it
    if (data->lParam->dwExtraInfo == KeyboardManagerConstants::KEYBOARDMANAGER_SUPPRESS_FLAG)
    {
        return 1;
    }

    // Remap a key
    intptr_t SingleKeyRemapResult = KeyboardEventHandlers::HandleSingleKeyRemapEvent(inputHandler, data, state);

    // Single key remaps have priority. If a key is remapped, only the remapped version should be visible to the shortcuts and hence the event should be suppressed here.
    if (SingleKeyRemapResult == 1)
    {
        return 1;
    }

    /* This feature has not been enabled (code from proof of concept stage)
        // Remap a key to behave like a modifier instead of a toggle
        intptr_t SingleKeyToggleToModResult = KeyboardEventHandlers::HandleSingleKeyToggleToModEvent(inputHandler, data, keyboardManagerState);
    */

    // Handle an app-specific shortcut remapping
    intptr_t AppSpecificShortcutRemapResult = KeyboardEventHandlers::HandleAppSpecificShortcutRemapEvent(inputHandler, data, state);

    // If an app-specific shortcut is remapped then the os-level shortcut remapping should be suppressed.
    if (AppSpecificShortcutRemapResult == 1)
    {
        return 1;
    }

    intptr_t SingleKeyToTextRemapResult = KeyboardEventHandlers::HandleSingleKeyToTextRemapEvent(inputHandler, data, state);

    if (SingleKeyToTextRemapResult == 1)
    {
        return 1;
    }

    // Handle an os-level shortcut remapping
    return KeyboardEventHandlers::HandleOSLevelShortcutRemapEvent(inputHandler, data, state);
}