modules: Keyboard Layout

This patch adds a new module to show the current keyboard layout.

Signed-off-by: Harish Krupo <harishkrupo@gmail.com>

include/IModule.hpp

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <gtkmm.h>
+#include <wayland-client.h>
 
 namespace waybar {
 
@@ -9,6 +10,7 @@ class IModule {
     virtual ~IModule() = default;
     virtual auto update() -> void = 0;
     virtual operator Gtk::Widget &() = 0;
+  virtual void handleSeat(struct wl_seat*, uint32_t) {};
     Glib::Dispatcher dp; // Hmmm Maybe I should create an abstract class ?
 };
 

include/bar.hpp

@@ -17,6 +17,7 @@ class Bar {
     Bar(const Bar&) = delete;
 
     auto toggle() -> void;
+  void handleSeat(struct wl_seat*, uint32_t);
 
     const Client& client;
     Gtk::Window window;

include/client.hpp

@@ -34,6 +34,8 @@ class Client {
       uint32_t name, const char *interface, uint32_t version);
     static void handleGlobalRemove(void *data,
       struct wl_registry *registry, uint32_t name);
+  static void seatName(void *data, struct wl_seat *wl_seat, const char *name) {}
+  static void seatCapabilities(void *data, struct wl_seat *wl_seat, uint32_t caps);
 };
 
 }

include/factory.hpp

@@ -19,6 +19,7 @@
 #ifdef HAVE_LIBPULSE
 #include "modules/pulseaudio.hpp"
 #endif
+#include "modules/kbdlayout.hpp"
 #include "modules/custom.hpp"
 
 namespace waybar {

include/modules/kbdlayout.hpp

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <fmt/format.h>
+#include <algorithm>
+#include "ALabel.hpp"
+#include <xkbcommon/xkbcommon.h>
+#include <wayland-client.h>
+#include <sys/mman.h>
+
+namespace waybar::modules {
+
+class KbdLayout : public ALabel {
+  public:
+    KbdLayout(const Json::Value&);
+    ~KbdLayout();
+    auto update() -> void;
+  void handleSeat(struct wl_seat* seat, uint32_t caps);
+  struct wl_keyboard *wl_kbd_ = nullptr;
+  struct xkb_context *xkb_ctx_ = nullptr;
+  struct xkb_keymap *keymap_ = nullptr;
+  struct xkb_state *xkb_state_ = nullptr;
+  uint32_t current_group_ = 0;
+
+private:
+
+static void kbdKeymap(void *data, struct wl_keyboard *wl_kbd, uint32_t format,
+                       int fd, uint32_t size);
+static void kbdEnter(void *data, struct wl_keyboard *wl_kbd, uint32_t serial,
+          struct wl_surface *surf, struct wl_array *keys) {}
+static void kbdLeave(void *data, struct wl_keyboard *wl_kbd, uint32_t serial, struct wl_surface *surf) {}
+
+static void kbdKey(void *data, struct wl_keyboard *wl_kbd, uint32_t serial, uint32_t time,
+        uint32_t key, uint32_t state) {}
+
+static void kbdModifiers(void *data, struct wl_keyboard *wl_kbd, uint32_t serial,
+                         uint32_t mods_depressed, uint32_t mods_latched,
+                         uint32_t mods_locked, uint32_t group);
+
+static void kbdRepeatInfo(void *data, struct wl_keyboard *wl_kbd, int32_t rate,
+                int32_t delay) {}
+  std::string layout_ = "EN";
+};
+
+}  // namespace waybar::modules

meson.build

@@ -39,6 +39,7 @@ sigcpp = dependency('sigc++-2.0')
 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'))
+xkbcommon = dependency('xkbcommon')
 
 src_files = files(
     'src/factory.cpp',
@@ -48,6 +49,7 @@ src_files = files(
     'src/modules/clock.cpp',
     'src/modules/custom.cpp',
     'src/modules/cpu.cpp',
+    'src/modules/kbdlayout.cpp',
     'src/main.cpp',
     'src/bar.cpp',
     'src/client.cpp'
@@ -109,7 +111,8 @@ executable(
         giounix,
         libnl,
         libnlgen,
-        libpulse
+        libpulse,
+	xkbcommon
     ],
     include_directories: [include_directories('include')],
     install: true,

resources/style.css

@@ -29,7 +29,7 @@ window#waybar {
     border-bottom: 3px solid white;
 }
 
-#clock, #battery, #cpu, #memory, #network, #pulseaudio, #custom-spotify, #tray, #mode {
+#clock, #battery, #cpu, #memory, #network, #pulseaudio, #custom-spotify, #tray, #mode, kbdlayout {
     padding: 0 10px;
     margin: 0 5px;
 }
@@ -100,3 +100,8 @@ window#waybar {
 #tray {
     background-color: #2980b9;
 }
+
+#kbdlayout {
+    background: #1f4d96;
+    color: white;
+}

src/bar.cpp

@@ -144,6 +144,21 @@ auto waybar::Bar::toggle() -> void
   wl_surface_commit(surface);
 }
 
+void waybar::Bar::handleSeat(struct wl_seat* seat, uint32_t caps) {
+  zwlr_layer_surface_v1_get_keyboard_modifiers(layer_surface, 1, seat);
+  wl_surface_commit(surface);
+
+  for (auto it = modules_left_.begin(); it != modules_left_.end(); ++it) {
+    (*it)->handleSeat(seat, caps);
+  }
+  for (auto it = modules_center_.begin(); it != modules_center_.end(); ++it) {
+    (*it)->handleSeat(seat, caps);
+  }
+  for (auto it = modules_right_.begin(); it != modules_right_.end(); ++it) {
+    (*it)->handleSeat(seat, caps);
+  }
+}
+
 auto waybar::Bar::setupConfig() -> void
 {
   std::ifstream file(client.config_file);

src/client.cpp

@@ -43,6 +43,13 @@ waybar::Client::Client(int argc, char* argv[])
 
 }
 
+void waybar::Client::seatCapabilities(void *data, struct wl_seat *wl_seat, uint32_t caps) {
+  auto o = static_cast<waybar::Client *>(data);
+  for (auto it = o->bars.begin(); it != o->bars.end(); ++it) {
+    (*it)->handleSeat(wl_seat, caps);
+  }
+}
+
 void waybar::Client::handleGlobal(void *data, struct wl_registry *registry,
   uint32_t name, const char *interface, uint32_t version)
 {
@@ -58,8 +65,13 @@ void waybar::Client::handleGlobal(void *data, struct wl_registry *registry,
       o->bars.emplace_back(std::make_unique<Bar>(*o, std::move(output), name));
     }
   } else if (strcmp(interface, wl_seat_interface.name) == 0) {
+    static const struct wl_seat_listener seat_listener = {
+                                                          seatCapabilities,
+                                                          seatName
+    };
     o->seat = static_cast<struct wl_seat *>(wl_registry_bind(registry, name,
       &wl_seat_interface, version));
+    wl_seat_add_listener(o->seat, &seat_listener, o);
   } else if (strcmp(interface, zxdg_output_manager_v1_interface.name) == 0
     && version >= ZXDG_OUTPUT_V1_NAME_SINCE_VERSION) {
       o->xdg_output_manager = static_cast<struct zxdg_output_manager_v1 *>(

src/factory.cpp

@@ -46,6 +46,9 @@ waybar::IModule* waybar::Factory::makeModule(const std::string &name) const
       return new waybar::modules::Pulseaudio(config_[name]);
     }
     #endif
+    if (ref == "kbdlayout") {
+      return new waybar::modules::KbdLayout(config_[name]);
+    }
     if (ref.compare(0, 7, "custom/") == 0 && ref.size() > 7) {
       return new waybar::modules::Custom(ref.substr(7), config_[name]);
     }

src/modules/kbdlayout.cpp

@@ -0,0 +1,87 @@
+#include "modules/kbdlayout.hpp"
+
+waybar::modules::KbdLayout::KbdLayout(const Json::Value &config)
+  : ALabel(config, "{layout}"), current_group_(0) {
+  label_.set_name("kbdlayout");
+  enum xkb_context_flags ctx_flags = static_cast<enum xkb_context_flags>(XKB_CONTEXT_NO_DEFAULT_INCLUDES | XKB_CONTEXT_NO_ENVIRONMENT_NAMES);
+  xkb_ctx_ = xkb_context_new(ctx_flags);
+}
+
+waybar::modules::KbdLayout::~KbdLayout() {
+  xkb_context_unref(xkb_ctx_);
+}
+
+void waybar::modules::KbdLayout::handleSeat(struct wl_seat* seat, uint32_t caps) {
+  static const struct wl_keyboard_listener kbd_listener = {
+                                                           kbdKeymap,
+                                                           kbdEnter,
+                                                           kbdLeave,
+                                                           kbdKey,
+                                                           kbdModifiers,
+                                                           kbdRepeatInfo
+  };
+
+  if (!wl_kbd_ && (caps & WL_SEAT_CAPABILITY_KEYBOARD)) {
+    wl_kbd_ = wl_seat_get_keyboard(seat);
+    wl_keyboard_add_listener(wl_kbd_, &kbd_listener, this);
+  } else if (wl_kbd_ && !(caps & WL_SEAT_CAPABILITY_KEYBOARD)) {
+    wl_keyboard_destroy(wl_kbd_);
+    wl_kbd_ = NULL;
+    xkb_keymap_unref(keymap_);
+    keymap_ = NULL;
+  }
+}
+
+auto waybar::modules::KbdLayout::update() -> void
+{
+  auto format = format_;
+
+  xkb_keycode_t keycode = 38;
+  xkb_layout_index_t layout = xkb_state_key_get_layout(xkb_state_, keycode);
+  layout_ = xkb_keymap_layout_get_name(keymap_, layout);
+
+  label_.set_label(fmt::format(format, fmt::arg("layout", layout_)));
+}
+
+void waybar::modules::KbdLayout::kbdKeymap(void *data, struct wl_keyboard *wl_kbd, uint32_t format, int fd, uint32_t size) {
+  auto o = static_cast<waybar::modules::KbdLayout *>(data);
+    void *buf;
+
+    buf = mmap(NULL, size, PROT_READ, MAP_PRIVATE, fd, 0);
+    if (buf == MAP_FAILED) {
+        printf("Failed to mmap keymap: %d\n", errno);
+        close(fd);
+        return;
+    }
+
+    o->keymap_ = xkb_keymap_new_from_buffer(o->xkb_ctx_, static_cast<const char*>(buf), size - 1,
+                                            XKB_KEYMAP_FORMAT_TEXT_V1, static_cast<enum xkb_keymap_compile_flags>(0));
+    munmap(buf, size);
+    close(fd);
+    if (!o->keymap_) {
+        printf("Failed to compile keymap!\n");
+        return;
+    }
+
+    o->xkb_state_ = xkb_state_new(o->keymap_);
+    if (!o->xkb_state_) {
+      printf("Failed to create XKB state!\n");
+      return;
+    }
+
+    o->dp.emit();
+}
+
+void waybar::modules::KbdLayout::kbdModifiers(void *data, struct wl_keyboard *wl_kbd, uint32_t serial,
+                                              uint32_t mods_depressed, uint32_t mods_latched,
+                                              uint32_t mods_locked, uint32_t group) {
+
+  auto o = static_cast<waybar::modules::KbdLayout *>(data);
+
+  xkb_state_update_mask(o->xkb_state_, mods_depressed, mods_latched,
+                        mods_locked, 0, 0, group);
+  if (o->current_group_ != group) {
+    o->current_group_ = group;
+    o->dp.emit();
+  }
+}