PowerToys/src/modules/shortcut_guide/target_state.cpp

#include "pch.h"
#include "target_state.h"
#include "common/start_visible.h"
#include "keyboard_state.h"

TargetState::TargetState(int ms_delay) : delay(std::chrono::milliseconds(ms_delay)), thread(&TargetState::thread_proc, this)
{ }

bool TargetState::signal_event(unsigned vk_code, bool key_down) {
  std::unique_lock lock(mutex);
  if (!events.empty() && events.back().key_down == key_down && events.back().vk_code == vk_code) {
    return false;
  }
  bool supress = false;
  if (!key_down && (vk_code == VK_LWIN || vk_code == VK_RWIN) &&
    state == Shown &&
    std::chrono::system_clock::now() - singnal_timestamp > std::chrono::milliseconds(300) &&
    !key_was_pressed) {
    supress = true;
  }
  events.push_back({ key_down, vk_code });
  lock.unlock();
  cv.notify_one();
  if (supress) {
    // Send a fake key-stroke to prevent the start menu from appearing.
    // We use 0x07 VK code, which is undefined. It still prevents the
    // start menu from appearing, but should not interfere with any
    // keyboard shortcuts.
    INPUT input[3] = { {},{},{} };
    input[0].type = INPUT_KEYBOARD;
    input[0].ki.wVk = 0x07;
    input[1].type = INPUT_KEYBOARD;
    input[1].ki.wVk = 0x07;
    input[1].ki.dwFlags = KEYEVENTF_KEYUP;
    input[2].type = INPUT_KEYBOARD;
    input[2].ki.wVk = VK_LWIN;
    input[2].ki.dwFlags = KEYEVENTF_KEYUP;
    SendInput(3, input, sizeof(INPUT));
  }
  return supress;
}

void TargetState::was_hiden() {
  std::unique_lock<std::mutex> lock(mutex);
  state = Hidden;
  events.clear();
  lock.unlock();
  cv.notify_one();
}

void TargetState::exit() {
  std::unique_lock lock(mutex);
  events.clear();
  state = Exiting;
  lock.unlock();
  cv.notify_one();
  thread.join();
}

KeyEvent TargetState::next() {
  auto e = events.front();
  events.pop_front();
  return e;
}

void TargetState::handle_hidden() {
  std::unique_lock lock(mutex);
  if (events.empty())
    cv.wait(lock);
  if (events.empty() || state == Exiting)
    return;
  auto event = next();
  if (event.key_down && (event.vk_code == VK_LWIN || event.vk_code == VK_RWIN)) {
    state = Timeout;
    winkey_timestamp = std::chrono::system_clock::now();
  }
}

void TargetState::handle_shown() {
  std::unique_lock lock(mutex);
  if (events.empty()) {
    cv.wait(lock);
  }
  if (events.empty() || state == Exiting) {
    return;
  }
  auto event = next();
  if (event.key_down && (event.vk_code == VK_LWIN || event.vk_code == VK_RWIN)) {
    return;
  }
  if (!event.key_down && (event.vk_code == VK_LWIN || event.vk_code == VK_RWIN) || !winkey_held()) {
    state = Hidden;
    lock.unlock();
    return;
  }
  if (event.key_down) {
    key_was_pressed = true;
    lock.unlock();
    instance->on_held_press(event.vk_code);
  }
}

void TargetState::thread_proc() {
  while (true) {
    switch (state) {
    case Hidden:
      handle_hidden();
      break;
    case Timeout:
      handle_timeout();
      break;
    case Shown:
      handle_shown();
      break;
    case Exiting:
    default:
      return;
    }
  }
}

void TargetState::handle_timeout() {
  std::unique_lock lock(mutex);
  auto wait_time = delay - (std::chrono::system_clock::now() - winkey_timestamp);
  if (events.empty())
    cv.wait_for(lock, wait_time);
  if (state == Exiting)
    return;
  while (!events.empty()) {
    auto event = events.front();
    if (event.key_down && (event.vk_code == VK_LWIN || event.vk_code == VK_RWIN))
      events.pop_front();
    else
      break;
  }
  if (!events.empty() || !only_winkey_key_held() || is_start_visible()) {
    state = Hidden;
    return;
  }
  if (std::chrono::system_clock::now() - winkey_timestamp < delay)
    return;
  singnal_timestamp = std::chrono::system_clock::now();
  key_was_pressed = false;
  state = Shown;
  lock.unlock();
  instance->on_held();
}

void TargetState::set_delay(int ms_delay) {
  delay = std::chrono::milliseconds(ms_delay);
}