feat: Add basic support for MPD

README.md

@@ -14,6 +14,7 @@
 - Memory
 - Cpu load average
 - Temperature
+- MPD
 - Custom scripts
 - Multiple output configuration
 - And much more customizations
@@ -49,6 +50,7 @@ libpulse [Pulseaudio module]
 libnl [Network module]
 sway [Sway modules]
 libdbusmenu-gtk3 [Tray module]
+libmpdclient [MPD module]
 ```
 
 Contributions welcome! - have fun :)<br>

include/factory.hpp

@@ -23,6 +23,9 @@
 #ifdef HAVE_LIBPULSE
 #include "modules/pulseaudio.hpp"
 #endif
+#ifdef HAVE_LIBMPDCLIENT
+#include "modules/mpd.hpp"
+#endif
 #include "modules/temperature.hpp"
 #include "modules/custom.hpp"
 

include/modules/mpd.hpp

@@ -0,0 +1,39 @@
+#pragma once
+
+#include <thread>
+#include <fmt/format.h>
+#include <mpd/client.h>
+#include "ALabel.hpp"
+
+namespace waybar::modules {
+
+class MPD : public ALabel {
+  public:
+    MPD(const std::string&, const Json::Value&);
+    auto update() -> void;
+  private:
+    std::thread worker();
+    void setLabel();
+    void tryConnect();
+    void checkErrors();
+    void fetchState();
+    void waitForEvent();
+
+    std::thread worker_;
+
+    using unique_connection = std::unique_ptr<mpd_connection, decltype(&mpd_connection_free)>;
+    using unique_status     = std::unique_ptr<mpd_status, decltype(&mpd_status_free)>;
+    using unique_song      = std::unique_ptr<mpd_song, decltype(&mpd_song_free)>;
+
+    // Not using unique_ptr since we don't manage the pointer
+    // (It's either nullptr, or from the config)
+    const char* server;
+
+    unique_connection connection_;
+    unique_status     status_;
+    unique_song       song_;
+
+    bool stopped_;
+};
+
+}  // namespace waybar::modules

meson.build

@@ -56,6 +56,7 @@ libnl = dependency('libnl-3.0', required: get_option('libnl'))
 libnlgen = dependency('libnl-genl-3.0', required: get_option('libnl'))
 libpulse = dependency('libpulse', required: get_option('pulseaudio'))
 libudev = dependency('libudev', required: get_option('libudev'))
+libmpdclient = dependency('libmpdclient', required: get_option('mpd'))
 
 src_files = files(
     'src/factory.cpp',
@@ -107,6 +108,11 @@ if libudev.found()
     src_files += 'src/modules/backlight.cpp'
 endif
 
+if libmpdclient.found()
+    add_project_arguments('-DHAVE_LIBMPDCLIENT', language: 'cpp')
+    src_files += 'src/modules/mpd.cpp'
+endif
+
 subdir('protocol')
 
 executable(
@@ -128,7 +134,8 @@ executable(
         libnl,
         libnlgen,
         libpulse,
-        libudev
+        libudev,
+        libmpdclient
     ],
     include_directories: [include_directories('include')],
     install: true,

meson_options.txt

@@ -2,4 +2,5 @@ option('libnl', type: 'feature', value: 'auto', description: 'Enable libnl suppo
 option('libudev', type: 'feature', value: 'auto', description: 'Enable libudev support for udev related features')
 option('pulseaudio', type: 'feature', value: 'auto', description: 'Enable support for pulseaudio')
 option('dbusmenu-gtk', type: 'feature', value: 'auto', description: 'Enable support for tray')
+option('mpd', type: 'feature', value: 'auto', description: 'Enable support for the Music Player Daemon')
 option('out', type: 'string', value : '/', description: 'output prefix directory')

resources/style.css

@@ -138,3 +138,16 @@ window#waybar.hidded {
     background-color: #ecf0f1;
     color: #2d3436;
 }
+
+#mpd {
+    background-color: #ba2880;
+}
+
+#mpd.disconnected {
+    background: #f53c3c;
+}
+
+#mpd.stopped {
+    background: #90b1b1;
+    color: #2a5c45;
+}

src/factory.cpp

@@ -56,6 +56,11 @@ waybar::IModule* waybar::Factory::makeModule(const std::string &name) const
       return new waybar::modules::Pulseaudio(id, config_[name]);
     }
     #endif
+    #ifdef HAVE_LIBMPDCLIENT
+    if (ref == "mpd") {
+      return new waybar::modules::MPD(id, config_[name]);
+    }
+    #endif
     if (ref == "temperature") {
       return new waybar::modules::Temperature(id, config_[name]);
     }

src/modules/mpd.cpp

@@ -0,0 +1,164 @@
+#include "modules/mpd.hpp"
+
+#include <iostream>
+
+waybar::modules::MPD::MPD(const std::string& id, const Json::Value &config)
+    : ALabel(config, "{album} - {artist} - {title}", 2),
+      server(nullptr),
+      connection_(nullptr, &mpd_connection_free),
+      status_(nullptr, &mpd_status_free),
+      song_(nullptr, &mpd_song_free) {
+  label_.set_name("mpd");
+  if (!id.empty()) {
+    label_.get_style_context()->add_class(id);
+  }
+
+  if (!config["server"].isNull()) {
+    server = config["server"].asCString();
+  }
+
+  worker_ = worker();
+}
+
+auto waybar::modules::MPD::update() -> void {
+  tryConnect();
+
+  if (connection_ != nullptr) {
+    try {
+      fetchState();
+    } catch (std::exception e) {
+      stopped_ = true;
+    }
+  }
+
+  setLabel();
+}
+
+std::thread waybar::modules::MPD::worker() {
+  return std::thread([this] () {
+      while (true) {
+        if (connection_ == nullptr) {
+          // Retry periodically if no connection
+          update();
+          std::this_thread::sleep_for(std::chrono::seconds(2));
+        } else {
+          // Else, update on any event
+          waitForEvent();
+          update();
+        }
+      }
+  });
+}
+
+void waybar::modules::MPD::setLabel() {
+  if (connection_ == nullptr) {
+    label_.get_style_context()->add_class("disconnected");
+    // In the case connection closed while MPD is stopped
+    label_.get_style_context()->remove_class("stopped");
+
+    auto format = config_["format-disconnected"].isString() ?
+      config_["format-disconnected"].asString() : "disconnected";
+    label_.set_markup(format);
+    return;
+  } else {
+    label_.get_style_context()->remove_class("disconnected");
+  }
+
+  auto format = format_;
+
+  std::string artist, album_artist, album, title, date;
+
+  if (stopped_) {
+    format = config_["format-stopped"].isString() ?
+      config_["format-stopped"].asString() : "stopped";
+    label_.get_style_context()->add_class("stopped");
+  } else {
+    label_.get_style_context()->remove_class("stopped");
+
+    artist       = mpd_song_get_tag(song_.get(), MPD_TAG_ARTIST, 0);
+    album_artist = mpd_song_get_tag(song_.get(), MPD_TAG_ALBUM_ARTIST, 0);
+    album        = mpd_song_get_tag(song_.get(), MPD_TAG_ALBUM, 0);
+    title        = mpd_song_get_tag(song_.get(), MPD_TAG_TITLE, 0);
+    date         = mpd_song_get_tag(song_.get(), MPD_TAG_DATE, 0);
+  }
+
+  label_.set_markup(fmt::format(format,
+        fmt::arg("artist", artist),
+        fmt::arg("album-artist", album_artist),
+        fmt::arg("album", album),
+        fmt::arg("title", title),
+        fmt::arg("date", date)));
+
+  if (tooltipEnabled()) {
+    std::string tooltip_format;
+    tooltip_format = config_["tooltip-format"].isString() ?
+      config_["tooltip-format"].asString() : "MPD";
+    auto tooltip_text = fmt::format(tooltip_format,
+        fmt::arg("artist", artist),
+        fmt::arg("album-artist", album_artist),
+        fmt::arg("album", album),
+        fmt::arg("title", title),
+        fmt::arg("date", date));
+    label_.set_tooltip_text(tooltip_text);
+  }
+}
+
+void waybar::modules::MPD::tryConnect() {
+  if (connection_ != nullptr) {
+    return;
+  }
+
+  connection_ = unique_connection(
+      mpd_connection_new(server, config_["port"].asUInt(), 5'000),
+      &mpd_connection_free);
+
+  if (connection_ == nullptr) {
+    std::cerr << "Failed to connect to MPD" << std::endl;
+    return;
+  }
+
+  try {
+    checkErrors();
+  } catch (std::runtime_error e) {
+    std::cerr << "Failed to connect to MPD: " << e.what() << std::endl;
+    connection_.reset();
+  }
+
+}
+
+void waybar::modules::MPD::checkErrors() {
+  auto conn = connection_.get();
+
+  switch (mpd_connection_get_error(conn)) {
+    case MPD_ERROR_SUCCESS:
+      return;
+    case MPD_ERROR_CLOSED:
+      std::cerr << "Connection to MPD closed" << std::endl;
+      mpd_connection_clear_error(conn);
+      connection_.reset();
+      return;
+    default:
+      auto error_message = mpd_connection_get_error_message(conn);
+      mpd_connection_clear_error(conn);
+      throw std::runtime_error(std::string(error_message));
+  }
+}
+
+void waybar::modules::MPD::fetchState() {
+    status_ = unique_status(mpd_run_status(connection_.get()), &mpd_status_free);
+    checkErrors();
+    mpd_state state = mpd_status_get_state(status_.get());
+    checkErrors();
+    stopped_ = state == MPD_STATE_UNKNOWN || state == MPD_STATE_STOP;
+
+    mpd_send_current_song(connection_.get());
+    song_ = unique_song(mpd_recv_song(connection_.get()), &mpd_song_free);
+    mpd_response_finish(connection_.get());
+    checkErrors();
+}
+
+void waybar::modules::MPD::waitForEvent() {
+  auto conn = connection_.get();
+  mpd_run_idle_mask(conn, MPD_IDLE_PLAYER /* | MPD_IDLE_OPTIONS */);
+  checkErrors();
+}