sndio: Add module.

- can control sndio: change volume, toggle mute
- appearance is somewhat dynamic: takes muted status into account
- uses polling inside sleeper thread to update values
- uses sioctl_* functions, requires sndio>=1.7.0.

src/factory.cpp

@@ -76,6 +76,11 @@ waybar::AModule* waybar::Factory::makeModule(const std::string& name) const {
     if (ref == "mpd") {
       return new waybar::modules::MPD(id, config_[name]);
     }
+#endif
+#ifdef HAVE_LIBSNDIO
+    if (ref == "sndio") {
+      return new waybar::modules::Sndio(id, config_[name]);
+    }
 #endif
     if (ref == "temperature") {
       return new waybar::modules::Temperature(id, config_[name]);

src/modules/sndio.cpp

@@ -0,0 +1,167 @@
+#include "modules/sndio.hpp"
+#include <algorithm>
+#include <cstdlib>
+#include <poll.h>
+#include <fmt/format.h>
+
+namespace waybar::modules {
+
+void ondesc(void *arg, struct sioctl_desc *d, int curval) {
+  auto self = static_cast<Sndio*>(arg);
+  if (d == NULL) {
+    // d is NULL when the list is done
+    return;
+  }
+  self->set_desc(d, curval);
+}
+
+void onval(void *arg, unsigned int addr, unsigned int val) {
+  auto self = static_cast<Sndio*>(arg);
+  self->put_val(addr, val);
+}
+
+Sndio::Sndio(const std::string &id, const Json::Value &config)
+    : ALabel(config, "sndio", id, "{volume}%"),
+      hdl_(nullptr),
+      pfds_(0),
+      addr_(0),
+      volume_(0),
+      old_volume_(0),
+      maxval_(0),
+      muted_(false) {
+  hdl_ = sioctl_open(SIO_DEVANY, SIOCTL_READ | SIOCTL_WRITE, 0);
+  if (hdl_ == nullptr) {
+    throw std::runtime_error("sioctl_open() failed.");
+  }
+
+  if(sioctl_ondesc(hdl_, ondesc, this) == 0) {
+    throw std::runtime_error("sioctl_ondesc() failed.");
+  }
+
+  sioctl_onval(hdl_, onval, this);
+
+  pfds_.reserve(sioctl_nfds(hdl_));
+
+  event_box_.show();
+
+  event_box_.add_events(Gdk::SCROLL_MASK | Gdk::SMOOTH_SCROLL_MASK | Gdk::BUTTON_PRESS_MASK);
+  event_box_.signal_scroll_event().connect(
+    sigc::mem_fun(*this, &Sndio::handleScroll));
+  event_box_.signal_button_press_event().connect(
+    sigc::mem_fun(*this, &Sndio::handleToggle));
+
+  thread_ = [this] {
+    dp.emit();
+
+    int nfds = sioctl_pollfd(hdl_, pfds_.data(), POLLIN);
+    if (nfds == 0) {
+      throw std::runtime_error("sioctl_pollfd() failed.");
+    }
+    while (poll(pfds_.data(), nfds, -1) < 0) {
+      if (errno != EINTR) {
+        throw std::runtime_error("poll() failed.");
+      }
+    }
+
+    int revents = sioctl_revents(hdl_, pfds_.data());
+    if (revents & POLLHUP) {
+      throw std::runtime_error("disconnected!");
+    }
+  };
+}
+
+Sndio::~Sndio() {
+  sioctl_close(hdl_);
+}
+
+auto Sndio::update() -> void {
+  auto format = format_;
+  unsigned int vol = 100. * static_cast<double>(volume_) / static_cast<double>(maxval_);
+
+  if (volume_ == 0) {
+    label_.get_style_context()->add_class("muted");
+  } else {
+    label_.get_style_context()->remove_class("muted");
+  }
+
+  label_.set_markup(fmt::format(format,
+                                fmt::arg("volume", vol),
+                                fmt::arg("raw_value", volume_)));
+
+  ALabel::update();
+}
+
+auto Sndio::set_desc(struct sioctl_desc *d, unsigned int val) -> void {
+  std::string name{d->func};
+  std::string node_name{d->node0.name};
+
+  if (name == "level" && node_name == "output" && d->type == SIOCTL_NUM) {
+    // store addr for output.level value, used in put_val
+    addr_ = d->addr;
+    maxval_ = d->maxval;
+    volume_ = val;
+  }
+}
+
+auto Sndio::put_val(unsigned int addr, unsigned int val) -> void {
+  if (addr == addr_) {
+    volume_ = val;
+  }
+}
+
+bool Sndio::handleScroll(GdkEventScroll *e) {
+  // change the volume only when no user provided
+  // events are configured
+  if (config_["on-scroll-up"].isString() || config_["on-scroll-down"].isString()) {
+    return AModule::handleScroll(e);
+  }
+
+  auto dir = AModule::getScrollDir(e);
+  if (dir == SCROLL_DIR::NONE) {
+    return true;
+  }
+
+  int step = 5;
+  if (config_["scroll-step"].isInt()) {
+    step = config_["scroll-step"].asInt();
+  }
+
+  int new_volume = volume_;
+  if (muted_) {
+    new_volume = old_volume_;
+  }
+
+  if (dir == SCROLL_DIR::UP) {
+    new_volume += step;
+  } else if (dir == SCROLL_DIR::DOWN) {
+    new_volume -= step;
+  }
+  new_volume = std::clamp(new_volume, 0, static_cast<int>(maxval_));
+
+  // quits muted mode if volume changes
+  muted_ = false;
+
+  sioctl_setval(hdl_, addr_, new_volume);
+
+  return true;
+}
+
+bool Sndio::handleToggle(GdkEventButton* const& e) {
+  // toggle mute only when no user provided events are configured
+  if (config_["on-click"].isString()) {
+    return AModule::handleToggle(e);
+  }
+
+  muted_ = !muted_;
+  if (muted_) {
+    // store old volume to be able to restore it later
+    old_volume_ = volume_;
+    sioctl_setval(hdl_, addr_, 0);
+  } else {
+    sioctl_setval(hdl_, addr_, old_volume_);
+  }
+
+  return true;
+}
+
+} /* namespace waybar::modules */