polybar-dwm/src/components/controller.cpp

#include <mutex>
#include <csignal>

#include "components/controller.hpp"
#include "components/signals.hpp"
#include "modules/backlight.hpp"
#include "modules/battery.hpp"
#include "modules/bspwm.hpp"
#include "modules/counter.hpp"
#include "modules/cpu.hpp"
#include "modules/date.hpp"
#include "modules/memory.hpp"
#include "modules/menu.hpp"
#include "modules/script.hpp"
#include "modules/text.hpp"
#include "modules/unsupported.hpp"
#include "modules/xbacklight.hpp"
#include "utils/process.hpp"
#include "utils/string.hpp"

#if ENABLE_I3
#include "modules/i3.hpp"
#endif
#if ENABLE_MPD
#include "modules/mpd.hpp"
#endif
#if ENABLE_NETWORK
#include "modules/network.hpp"
#endif
#if ENABLE_ALSA
#include "modules/volume.hpp"
#endif

LEMONBUDDY_NS

using namespace modules;

/**
 * Stop modules and cleanup X components,
 * threads and spawned processes
 */
controller::~controller() {
  g_signals::bar::action_click = nullptr;

  if (m_command) {
    m_log.info("Terminating running shell command");
    m_command->terminate();
  }

  if (m_eventloop) {
    m_log.info("Deconstructing eventloop");
    m_eventloop->set_update_cb(nullptr);
    m_eventloop->set_input_db(nullptr);
    m_eventloop.reset();
  }

  if (m_bar) {
    m_log.info("Deconstructing bar");
    m_bar.reset();
  }

  m_log.info("Interrupting X event loop");
  m_connection.send_dummy_event(m_connection.root());

  if (!m_threads.empty()) {
    m_log.info("Joining active threads");
    for (auto&& thread : m_threads) {
      if (thread.joinable())
        thread.join();
    }
  }

  m_log.info("Waiting for spawned processes");
  while (process_util::notify_childprocess())
    ;

  m_connection.flush();
}

/**
 * Setup X environment
 */
void controller::bootstrap(bool writeback, bool dump_wmname) {
  m_writeback = writeback;

  m_log.trace("controller: Initialize X atom cache");
  m_connection.preload_atoms();

  m_log.trace("controller: Query X extension data");
  m_connection.query_extensions();

  // Listen for events on the root window to be able to
  // break the blocking wait call when cleaning up
  m_log.trace("controller: Listen for events on the root window");
  try {
    const uint32_t value_list[2]{XCB_EVENT_MASK_PROPERTY_CHANGE | XCB_EVENT_MASK_STRUCTURE_NOTIFY};
    m_connection.change_window_attributes_checked(
        m_connection.root(), XCB_CW_EVENT_MASK, value_list);
  } catch (const std::exception& err) {
    throw application_error("Failed to change root window event mask: " + string{err.what()});
  }

  try {
    m_log.trace("controller: Setup bar");
    m_bar->bootstrap(m_writeback || dump_wmname);
  } catch (const std::exception& err) {
    throw application_error("Failed to setup bar renderer: " + string{err.what()});
  }

  if (dump_wmname) {
    std::cout << m_bar->settings().wmname << std::endl;
    return;
  }

  m_log.trace("controller: Attach eventloop callbacks");
  m_eventloop->set_update_cb(bind(&controller::on_update, this));

  if (!m_writeback) {
    g_signals::bar::action_click = bind(&controller::on_mouse_event, this, placeholders::_1);
    m_eventloop->set_input_db(bind(&controller::on_unrecognized_action, this, placeholders::_1));
  }

  m_log.trace("controller: Setup user-defined modules");
  bootstrap_modules();
}

/**
 * Launch the controller
 */
bool controller::run() {
  assert(!m_connection.connection_has_error());

  m_log.info("Starting application");
  m_running = true;

  install_sigmask();
  install_confwatch();

  // Listen for X events in separate thread
  if (!m_writeback) {
    m_threads.emplace_back(thread(&controller::wait_for_xevent, this));
  }

  // Wait for term signal in separate thread
  m_threads.emplace_back(thread(&controller::wait_for_signal, this));

  // Start event loop
  if (m_eventloop) {
    auto throttle_ms = m_conf.get<double>("settings", "throttle-ms", 10);
    auto throttle_limit = m_conf.get<int>("settings", "throttle-limit", 5);
    m_eventloop->run(chrono::duration<double, std::milli>(throttle_ms), throttle_limit);
  }

  // Wake up signal thread
  if (m_waiting) {
    kill(getpid(), SIGTERM);
  }

  uninstall_sigmask();
  uninstall_confwatch();

  m_running = false;

  return !m_reload;
}

/**
 * Set signal mask for the current and future threads
 */
void controller::install_sigmask() {
  m_log.trace("controller: Set pthread_sigmask to block term signals");

  sigemptyset(&m_waitmask);
  sigaddset(&m_waitmask, SIGINT);
  sigaddset(&m_waitmask, SIGQUIT);
  sigaddset(&m_waitmask, SIGTERM);
  sigaddset(&m_waitmask, SIGUSR1);

  if (pthread_sigmask(SIG_BLOCK, &m_waitmask, nullptr) == -1)
    throw system_error();

  sigemptyset(&m_ignmask);
  sigaddset(&m_ignmask, SIGPIPE);

  if (pthread_sigmask(SIG_BLOCK, &m_ignmask, nullptr) == -1)
    throw system_error();
}

/**
 * Uninstall sigmask to allow term signals
 */
void controller::uninstall_sigmask() {
  m_log.trace("controller: Set pthread_sigmask to unblock term signals");

  if (pthread_sigmask(SIG_UNBLOCK, &m_waitmask, nullptr) == -1)
    throw system_error();
}

/**
 * Listen for changes to the config file
 */
void controller::install_confwatch() {
  if (!m_running)
    return;

  if (!m_confwatch) {
    m_log.trace("controller: Config watch not set, skip...");
    return;
  }

  m_threads.emplace_back([this] {
    this_thread::sleep_for(1s);

    try {
      if (!m_running)
        return;

      m_log.trace("controller: Attach config watch");
      m_confwatch->attach(IN_MODIFY);

      m_log.trace("controller: Wait for config file inotify event");
      m_confwatch->get_event();

      if (!m_running)
        return;

      m_log.info("Configuration file changed");
      kill(getpid(), SIGUSR1);
    } catch (const system_error& err) {
      m_log.err(err.what());
      m_log.trace("controller: Reset config watch");
      m_confwatch.reset();
    }
  });
}

/**
 * Remove the config inotify watch
 */
void controller::uninstall_confwatch() {
  try {
    if (m_confwatch) {
      m_log.info("Removing config watch");
      m_confwatch->remove();
    }
  } catch (const system_error& err) {
  }
}

/**
 * Wait for termination signal
 */
void controller::wait_for_signal() {
  m_log.trace("controller: Wait for signal");
  m_waiting = true;

  int caught_signal = 0;
  sigwait(&m_waitmask, &caught_signal);

  m_log.warn("Termination signal received, shutting down...");
  m_log.trace("controller: Caught signal %d", caught_signal);

  if (m_eventloop) {
    m_eventloop->stop();
  }

  m_reload = (caught_signal == SIGUSR1);
  m_waiting = false;
}

/**
 * Wait for X events and forward them to
 * the event registry
 */
void controller::wait_for_xevent() {
  m_log.trace("controller: Listen for X events");

  m_connection.flush();

  while (m_running) {
    try {
      int error = 0;

      if ((error = m_connection.connection_has_error()) != 0) {
        m_log.err("Error in X event loop, aborting... (%s)", m_connection.error_str(error));
        break;
      }

      auto evt = m_connection.wait_for_event();

      if (evt != nullptr) {
        m_connection.dispatch_event(evt);
      }
    } catch (const std::exception& err) {
      m_log.err("Error in X event loop: %s", err.what());
    }
  }
}

/**
 * Create and initialize bar modules
 */
void controller::bootstrap_modules() {
  const bar_settings bar{m_bar->settings()};
  string bs{m_conf.bar_section()};
  size_t module_count = 0;

  for (int i = 0; i < 3; i++) {
    alignment align = static_cast<alignment>(i + 1);
    string confkey;

    switch (align) {
      case alignment::LEFT:
        confkey = "modules-left";
        break;
      case alignment::CENTER:
        confkey = "modules-center";
        break;
      case alignment::RIGHT:
        confkey = "modules-right";
        break;
      default:
        break;
    }

    for (auto& module_name : string_util::split(m_conf.get<string>(bs, confkey, ""), ' ')) {
      try {
        auto type = m_conf.get<string>("module/" + module_name, "type");
        module_t module;

        if (type == "internal/counter")
          module.reset(new counter_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/backlight")
          module.reset(new backlight_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/xbacklight")
          module.reset(new xbacklight_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/battery")
          module.reset(new battery_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/bspwm")
          module.reset(new bspwm_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/cpu")
          module.reset(new cpu_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/date")
          module.reset(new date_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/memory")
          module.reset(new memory_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/i3")
          module.reset(new i3_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/mpd")
          module.reset(new mpd_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/volume")
          module.reset(new volume_module(bar, m_log, m_conf, module_name));
        else if (type == "internal/network")
          module.reset(new network_module(bar, m_log, m_conf, module_name));
        else if (type == "custom/text")
          module.reset(new text_module(bar, m_log, m_conf, module_name));
        else if (type == "custom/script")
          module.reset(new script_module(bar, m_log, m_conf, module_name));
        else if (type == "custom/menu")
          module.reset(new menu_module(bar, m_log, m_conf, module_name));
        else
          throw application_error("Unknown module: " + module_name);

        module->set_update_cb(bind(&eventloop::enqueue, m_eventloop.get(),
            eventloop::entry_t{static_cast<int>(event_type::UPDATE)}));
        module->set_stop_cb(bind(&eventloop::enqueue, m_eventloop.get(),
            eventloop::entry_t{static_cast<int>(event_type::CHECK)}));

        module->setup();

        m_eventloop->add_module(align, move(module));

        module_count++;
      } catch (const std::runtime_error& err) {
        m_log.err("Disabling module \"%s\" (error: %s)", module_name, err.what());
      }
    }
  }

  if (module_count == 0)
    throw application_error("No modules created");
}

/**
 * Callback for clicked bar actions
 */
void controller::on_mouse_event(string input) {
  eventloop::entry_t evt{static_cast<int>(event_type::INPUT)};

  if (input.length() > sizeof(evt.data)) {
    m_log.warn("Ignoring input event (size)");
  } else {
    snprintf(evt.data, sizeof(evt.data), "%s", input.c_str());
    m_eventloop->enqueue(evt);
  }
}

/**
 * Callback for actions not handled internally by a module
 */
void controller::on_unrecognized_action(string input) {
  try {
    if (m_command) {
      m_log.warn("Terminating previous shell command");
      m_command->terminate();
    }

    m_log.info("Executing shell command: %s", input);

    m_command = command_util::make_command(input);
    m_command->exec();
    m_command.reset();
  } catch (const application_error& err) {
    m_log.err("controller: Error while forwarding input to shell -> %s", err.what());
  }
}

/**
 * Callback for module content update
 */
void controller::on_update() {
  string contents{""};
  string separator{m_bar->settings().separator};

  string padding_left(m_bar->settings().padding_left, ' ');
  string padding_right(m_bar->settings().padding_right, ' ');

  auto margin_left = m_bar->settings().module_margin_left;
  auto margin_right = m_bar->settings().module_margin_right;

  for (const auto& block : m_eventloop->modules()) {
    string block_contents;
    bool is_left = false;
    bool is_center = false;
    bool is_right = false;

    if (block.first == alignment::LEFT)
      is_left = true;
    else if (block.first == alignment::CENTER)
      is_center = true;
    else if (block.first == alignment::RIGHT)
      is_right = true;

    for (const auto& module : block.second) {
      auto module_contents = module->contents();

      if (module_contents.empty())
        continue;

      if (!block_contents.empty() && !separator.empty())
        block_contents += separator;

      if (!(is_left && module == block.second.front()))
        block_contents += string(margin_left, ' ');

      block_contents += module->contents();

      if (!(is_right && module == block.second.back()))
        block_contents += string(margin_right, ' ');
    }

    if (block_contents.empty())
      continue;

    if (is_left) {
      contents += "%{l}";
      contents += padding_left;
    } else if (is_center) {
      contents += "%{c}";
    } else if (is_right) {
      contents += "%{r}";
      block_contents += padding_right;
    }

    block_contents = string_util::replace_all(block_contents, "B-}%{B#", "B#");
    block_contents = string_util::replace_all(block_contents, "F-}%{F#", "F#");
    block_contents = string_util::replace_all(block_contents, "T-}%{T", "T");
    contents += string_util::replace_all(block_contents, "}%{", " ");
  }

  if (m_writeback) {
    std::cout << contents << std::endl;
  } else {
    m_bar->parse(contents);
  }

  if (!m_trayactivated) {
    m_trayactivated = true;
    m_bar->activate_tray();
  }
}

LEMONBUDDY_NS_END