Implement Tray Icons

This commit implements the StatusNotifierItem protocol, and enables
swaybar to show tray icons. It also uses `xembedsniproxy` in order to
communicate with xembed applications.
The tray is completely optional, and can be disabled on compile time
with the `enable-tray` option. Or on runtime with the bar config option
`tray_output none`.

Overview of changes:
In swaybar very little is changed outside the tray subfolder except
that all events are now polled in `event_loop.c`, this creates no
functional difference.

Six bar configuration options were added, these are detailed in
sway-bar(5)

The tray subfolder is where all protocol implementation takes place and
is organised as follows:

tray/sni_watcher.c:
	This file contains the StatusNotifierWatcher. It keeps track of
	items and hosts and reports when they come or go.
tray/tray.c
	This file contains the StatusNotifierHost. It keeps track of
	sway's version of the items and represents the tray itself.
tray/sni.c
	This file contains the StatusNotifierItem struct and all
	communication with individual items.
tray/icon.c
	This file implements the icon theme protocol. It allows for
	finding icons by name, rather than by pixmap.
tray/dbus.c
	This file allows for asynchronous DBus communication.

See #986 #343

CMake/FindDBus.cmake

@@ -0,0 +1,59 @@
+# - Try to find DBus
+# Once done, this will define
+#
+#  DBUS_FOUND - system has DBus
+#  DBUS_INCLUDE_DIRS - the DBus include directories
+#  DBUS_LIBRARIES - link these to use DBus
+#
+# Copyright (C) 2012 Raphael Kubo da Costa <rakuco@webkit.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1.  Redistributions of source code must retain the above copyright
+#     notice, this list of conditions and the following disclaimer.
+# 2.  Redistributions in binary form must reproduce the above copyright
+#     notice, this list of conditions and the following disclaimer in the
+#     documentation and/or other materials provided with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND ITS CONTRIBUTORS ``AS
+# IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR ITS
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+# EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+# PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+# OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+# WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+# OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+# ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+FIND_PACKAGE(PkgConfig)
+PKG_CHECK_MODULES(PC_DBUS QUIET dbus-1)
+
+FIND_LIBRARY(DBUS_LIBRARIES
+    NAMES dbus-1
+    HINTS ${PC_DBUS_LIBDIR}
+          ${PC_DBUS_LIBRARY_DIRS}
+)
+
+FIND_PATH(DBUS_INCLUDE_DIR
+    NAMES dbus/dbus.h
+    HINTS ${PC_DBUS_INCLUDEDIR}
+          ${PC_DBUS_INCLUDE_DIRS}
+)
+
+GET_FILENAME_COMPONENT(_DBUS_LIBRARY_DIR ${DBUS_LIBRARIES} PATH)
+FIND_PATH(DBUS_ARCH_INCLUDE_DIR
+    NAMES dbus/dbus-arch-deps.h
+    HINTS ${PC_DBUS_INCLUDEDIR}
+          ${PC_DBUS_INCLUDE_DIRS}
+          ${_DBUS_LIBRARY_DIR}
+          ${DBUS_INCLUDE_DIR}
+    PATH_SUFFIXES include
+)
+
+SET(DBUS_INCLUDE_DIRS ${DBUS_INCLUDE_DIR} ${DBUS_ARCH_INCLUDE_DIR})
+
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(DBUS REQUIRED_VARS DBUS_INCLUDE_DIRS DBUS_LIBRARIES)

CMakeLists.txt

@@ -47,6 +47,7 @@ option(enable-swaybar "Enables the swaybar utility" YES)
 option(enable-swaygrab "Enables the swaygrab utility" YES)
 option(enable-swaymsg "Enables the swaymsg utility" YES)
 option(enable-gdk-pixbuf "Use Pixbuf to support more image formats" YES)
+option(enable-tray "Enables the swaybar tray" YES)
 option(zsh-completions "Zsh shell completions" NO)
 option(default-wallpaper "Installs the default wallpaper" YES)
 option(LD_LIBRARY_PATH "Configure sway's default LD_LIBRARY_PATH")
@@ -64,6 +65,7 @@ find_package(Cairo REQUIRED)
 find_package(Pango REQUIRED)
 find_package(GdkPixbuf)
 find_package(PAM)
+find_package(DBus)
 
 find_package(LibInput REQUIRED)
 
@@ -90,6 +92,17 @@ else()
 	message(STATUS "Building without gdk-pixbuf, only png images supported.")
 endif()
 
+if (enable-tray)
+	if (DBUS_FOUND)
+		set(ENABLE_TRAY)
+		add_definitions(-DENABLE_TRAY)
+	else()
+		message(WARNING "Tray required but DBus was not found. Tray will not be included")
+	endif()
+else()
+	message(STATUS "Building without the tray.")
+endif()
+
 include_directories(include)
 
 add_subdirectory(protocols)

include/client/cairo.h

@@ -6,6 +6,8 @@
 
 void cairo_set_source_u32(cairo_t *cairo, uint32_t color);
 
+cairo_surface_t *cairo_image_surface_scale(cairo_surface_t *image, int width, int height);
+
 #ifdef WITH_GDK_PIXBUF
 #include <gdk-pixbuf/gdk-pixbuf.h>
 

include/sway/commands.h

@@ -157,17 +157,21 @@ sway_cmd cmd_workspace;
 sway_cmd cmd_ws_auto_back_and_forth;
 sway_cmd cmd_workspace_layout;
 
+sway_cmd bar_cmd_activate_button;
 sway_cmd bar_cmd_binding_mode_indicator;
 sway_cmd bar_cmd_bindsym;
 sway_cmd bar_cmd_colors;
+sway_cmd bar_cmd_context_button;
 sway_cmd bar_cmd_font;
 sway_cmd bar_cmd_mode;
 sway_cmd bar_cmd_modifier;
 sway_cmd bar_cmd_output;
 sway_cmd bar_cmd_height;
 sway_cmd bar_cmd_hidden_state;
+sway_cmd bar_cmd_icon_theme;
 sway_cmd bar_cmd_id;
 sway_cmd bar_cmd_position;
+sway_cmd bar_cmd_secondary_button;
 sway_cmd bar_cmd_separator_symbol;
 sway_cmd bar_cmd_status_command;
 sway_cmd bar_cmd_pango_markup;

include/sway/config.h

@@ -133,7 +133,17 @@ struct bar_config {
 	char *swaybar_command;
 	char *font;
 	int height; // -1 not defined
-	int tray_padding;
+
+#ifdef ENABLE_TRAY
+	// Tray
+	char *tray_output;
+	char *icon_theme;
+	uint32_t tray_padding;
+	uint32_t activate_button;
+	uint32_t context_button;
+	uint32_t secondary_button;
+#endif
+
 	bool workspace_buttons;
 	bool wrap_scroll;
 	char *separator_symbol;

include/swaybar/bar.h

@@ -21,6 +21,9 @@ struct output {
 	struct window *window;
 	struct registry *registry;
 	list_t *workspaces;
+#ifdef ENABLE_TRAY
+	list_t *items;
+#endif
 	char *name;
 	int idx;
 	bool focused;
@@ -37,6 +40,9 @@ struct workspace {
 /** Global bar state */
 extern struct bar swaybar;
 
+/** True if sway needs to render */
+extern bool dirty;
+
 /**
  * Setup bar.
  */

include/swaybar/config.h

@@ -33,6 +33,17 @@ struct config {
 	bool all_outputs;
 	list_t *outputs;
 
+#ifdef ENABLE_TRAY
+	// Tray
+	char *tray_output;
+	char *icon_theme;
+
+	uint32_t tray_padding;
+	uint32_t activate_button;
+	uint32_t context_button;
+	uint32_t secondary_button;
+#endif
+
 	int height;
 
 	struct {

include/swaybar/event_loop.h

@@ -0,0 +1,26 @@
+#ifndef _SWAYBAR_EVENT_LOOP_H
+#define _SWAYBAR_EVENT_LOOP_H
+
+#include <stdbool.h>
+#include <time.h>
+
+void add_event(int fd, short mask,
+		void(*cb)(int fd, short mask, void *data),
+		void *data);
+
+// Not guaranteed to notify cb immediately
+void add_timer(timer_t timer,
+		void(*cb)(timer_t timer, void *data),
+		void *data);
+
+// Returns false if nothing exists, true otherwise
+bool remove_event(int fd);
+
+// Returns false if nothing exists, true otherwise
+bool remove_timer(timer_t timer);
+
+// Blocks and returns after sending callbacks
+void event_loop_poll();
+
+void init_event_loop();
+#endif /*_SWAYBAR_EVENT_LOOP_H */

include/swaybar/tray/dbus.h

@@ -0,0 +1,18 @@
+#ifndef _SWAYBAR_DBUS_H
+#define _SWAYBAR_DBUS_H
+
+#include <stdbool.h>
+#include <dbus/dbus.h>
+extern DBusConnection *conn;
+
+/**
+ * Should be called in main loop to dispatch events
+ */
+void dispatch_dbus();
+
+/**
+ * Initializes async dbus communication
+ */
+int dbus_init();
+
+#endif /* _SWAYBAR_DBUS_H */

include/swaybar/tray/icon.h

@@ -0,0 +1,16 @@
+#ifndef _SWAYBAR_ICON_H
+#define _SWAYBAR_ICON_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <client/cairo.h>
+
+/**
+ * Returns the image found by `name` that is closest to `size`
+ */
+cairo_surface_t *find_icon(const char *name, int size);
+
+/* Struct used internally only */
+struct subdir;
+
+#endif /* _SWAYBAR_ICON_H */

include/swaybar/tray/sni.h

@@ -0,0 +1,81 @@
+#ifndef _SWAYBAR_SNI_H
+#define _SWAYBAR_SNI_H
+
+#include <stdbool.h>
+#include <client/cairo.h>
+
+struct StatusNotifierItem {
+	/* Name registered to sni watcher */
+	char *name;
+	/* Unique bus name, needed for determining signal origins */
+	char *unique_name;
+	bool kde_special_snowflake;
+
+	cairo_surface_t *image;
+	bool dirty;
+};
+
+/* Each output holds an sni_icon_ref of each item to render */
+struct sni_icon_ref {
+	cairo_surface_t *icon;
+	struct StatusNotifierItem *ref;
+};
+
+struct sni_icon_ref *sni_icon_ref_create(struct StatusNotifierItem *item,
+		int height);
+
+void sni_icon_ref_free(struct sni_icon_ref *sni_ref);
+
+/**
+ * Will return a new item and get its icon. (see warning below)
+ */
+struct StatusNotifierItem *sni_create(const char *name);
+
+/**
+ * `item` must be a struct StatusNotifierItem *
+ * `str` must be a NUL terminated char *
+ *
+ * Returns 0 if `item` has a name of `str`
+ */
+int sni_str_cmp(const void *item, const void *str);
+
+/**
+ * Returns 0 if `item` has a unique name of `str` or if
+ * `item->unique_name == NULL`
+ */
+int sni_uniq_cmp(const void *item, const void *str);
+
+/**
+ * Gets an icon for the given item if found.
+ *
+ * XXX
+ * This function keeps a reference to the item until it gets responses, make
+ * sure that the reference and item are valid during this time.
+ */
+void get_icon(struct StatusNotifierItem *item);
+
+/**
+ * Calls the "activate" method on the given StatusNotifierItem
+ *
+ * x and y should be where the item was clicked
+ */
+void sni_activate(struct StatusNotifierItem *item, uint32_t x, uint32_t y);
+
+/**
+ * Asks the item to draw a context menu at the given x and y coords
+ */
+void sni_context_menu(struct StatusNotifierItem *item, uint32_t x, uint32_t y);
+
+/**
+ * Calls the "secondary activate" method on the given StatusNotifierItem
+ *
+ * x and y should be where the item was clicked
+ */
+void sni_secondary(struct StatusNotifierItem *item, uint32_t x, uint32_t y);
+
+/**
+ * Deconstructs `item`
+ */
+void sni_free(struct StatusNotifierItem *item);
+
+#endif /* _SWAYBAR_SNI_H */

include/swaybar/tray/sni_watcher.h

@@ -0,0 +1,10 @@
+#ifndef _SWAYBAR_SNI_WATCHER_H
+#define _SWAYBAR_SNI_WATCHER_H
+
+/**
+ * Starts the sni_watcher, the watcher is practically a black box and should
+ * only be accessed though functions described in its spec
+ */
+int init_sni_watcher();
+
+#endif /* _SWAYBAR_SNI_WATCHER_H */

include/swaybar/tray/tray.h

@@ -0,0 +1,26 @@
+#ifndef _SWAYBAR_TRAY_H
+#define _SWAYBAR_TRAY_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include "swaybar/tray/dbus.h"
+#include "swaybar/tray/sni.h"
+#include "list.h"
+
+extern struct tray *tray;
+
+struct tray {
+	list_t *items;
+};
+
+/**
+ * Initializes the tray host with D-Bus
+ */
+int init_tray();
+
+/**
+ * Returns an item if `x` and `y` collide with it and NULL otherwise
+ */
+struct StatusNotifierItem *collides_with_sni(int x, int y);
+
+#endif /* _SWAYBAR_TRAY_H */

sway/commands.c

@@ -221,18 +221,22 @@ static struct cmd_handler handlers[] = {
 };
 
 static struct cmd_handler bar_handlers[] = {
+	{ "activate_button", bar_cmd_activate_button },
 	{ "binding_mode_indicator", bar_cmd_binding_mode_indicator },
 	{ "bindsym", bar_cmd_bindsym },
 	{ "colors", bar_cmd_colors },
+	{ "context_button", bar_cmd_context_button },
 	{ "font", bar_cmd_font },
 	{ "height", bar_cmd_height },
 	{ "hidden_state", bar_cmd_hidden_state },
+	{ "icon_theme", bar_cmd_icon_theme },
 	{ "id", bar_cmd_id },
 	{ "mode", bar_cmd_mode },
 	{ "modifier", bar_cmd_modifier },
 	{ "output", bar_cmd_output },
 	{ "pango_markup", bar_cmd_pango_markup },
 	{ "position", bar_cmd_position },
+	{ "secondary_button", bar_cmd_secondary_button },
 	{ "separator_symbol", bar_cmd_separator_symbol },
 	{ "status_command", bar_cmd_status_command },
 	{ "strip_workspace_numbers", bar_cmd_strip_workspace_numbers },

sway/commands/bar/activate_button.c

@@ -0,0 +1,26 @@
+#include <stdlib.h>
+#include "sway/commands.h"
+#include "log.h"
+
+struct cmd_results *bar_cmd_activate_button(int argc, char **argv) {
+	const char *cmd_name = "activate_button";
+#ifndef ENABLE_TRAY
+	return cmd_results_new(CMD_INVALID, cmd_name, "Invalid %s command "
+			"%s called, but sway was compiled without tray support",
+			cmd_name, cmd_name);
+#else
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, cmd_name, EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+
+	if (!config->current_bar) {
+		return cmd_results_new(CMD_FAILURE, cmd_name, "No bar defined.");
+	}
+
+	// User should be able to prefix with 0x or whatever they want
+	config->current_bar->secondary_button = strtoul(argv[0], NULL, 0);
+
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+#endif
+}

sway/commands/bar/context_button.c

@@ -0,0 +1,26 @@
+#include <stdlib.h>
+#include "sway/commands.h"
+#include "log.h"
+
+struct cmd_results *bar_cmd_context_button(int argc, char **argv) {
+	const char *cmd_name = "context_button";
+#ifndef ENABLE_TRAY
+	return cmd_results_new(CMD_INVALID, cmd_name, "Invalid %s command "
+			"%s called, but sway was compiled without tray support",
+			cmd_name, cmd_name);
+#else
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, cmd_name, EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+
+	if (!config->current_bar) {
+		return cmd_results_new(CMD_FAILURE, cmd_name, "No bar defined.");
+	}
+
+	// User should be able to prefix with 0x or whatever they want
+	config->current_bar->context_button = strtoul(argv[0], NULL, 0);
+
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+#endif
+}

sway/commands/bar/icon_theme.c

@@ -0,0 +1,25 @@
+#define _XOPEN_SOURCE 500
+#include <string.h>
+#include "sway/commands.h"
+
+struct cmd_results *bar_cmd_icon_theme(int argc, char **argv) {
+	const char *cmd_name = "tray_output";
+#ifndef ENABLE_TRAY
+	return cmd_results_new(CMD_INVALID, cmd_name, "Invalid %s command "
+			"%s called, but sway was compiled without tray support",
+			cmd_name, cmd_name);
+#else
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, cmd_name, EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+
+	if (!config->current_bar) {
+		return cmd_results_new(CMD_FAILURE, cmd_name, "No bar defined.");
+	}
+
+	config->current_bar->icon_theme = strdup(argv[0]);
+
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+#endif
+}

sway/commands/bar/secondary_button.c

@@ -0,0 +1,26 @@
+#include <stdlib.h>
+#include "sway/commands.h"
+#include "log.h"
+
+struct cmd_results *bar_cmd_secondary_button(int argc, char **argv) {
+	const char *cmd_name = "secondary_button";
+#ifndef ENABLE_TRAY
+	return cmd_results_new(CMD_INVALID, cmd_name, "Invalid %s command "
+			"%s called, but sway was compiled without tray support",
+			cmd_name, cmd_name);
+#else
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, cmd_name, EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+
+	if (!config->current_bar) {
+		return cmd_results_new(CMD_FAILURE, cmd_name, "No bar defined.");
+	}
+
+	// User should be able to prefix with 0x or whatever they want
+	config->current_bar->secondary_button = strtoul(argv[0], NULL, 0);
+
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+#endif
+}

sway/commands/bar/tray_output.c

@@ -1,7 +1,29 @@
+#define _XOPEN_SOURCE 500
+#include <string.h>
 #include "sway/commands.h"
-#include "log.h"
 
 struct cmd_results *bar_cmd_tray_output(int argc, char **argv) {
-	sway_log(L_ERROR, "Warning: tray_output is not supported on wayland");
+	const char *cmd_name = "tray_output";
+#ifndef ENABLE_TRAY
+	return cmd_results_new(CMD_INVALID, cmd_name, "Invalid %s command "
+			"%s called, but sway was compiled without tray support",
+			cmd_name, cmd_name);
+#else
+	struct cmd_results *error = NULL;
+	if ((error = checkarg(argc, cmd_name, EXPECTED_EQUAL_TO, 1))) {
+		return error;
+	}
+
+	if (!config->current_bar) {
+		return cmd_results_new(CMD_FAILURE, cmd_name, "No bar defined.");
+	}
+
+	if (strcmp(argv[0], "all") == 0) {
+		// Default behaviour
+		return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+	}
+	config->current_bar->tray_output = strdup(argv[0]);
+
 	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+#endif
 }

sway/commands/bar/tray_padding.c

@@ -1,30 +1,34 @@
 #include <stdlib.h>
-#include <string.h>
 #include <strings.h>
 #include "sway/commands.h"
 #include "log.h"
 
 struct cmd_results *bar_cmd_tray_padding(int argc, char **argv) {
+	const char *cmd_name = "tray_padding";
+#ifndef ENABLE_TRAY
+	return cmd_results_new(CMD_INVALID, cmd_name, "Invalid %s command"
+			"%s called, but sway was compiled without tray support",
+			cmd_name, cmd_name);
+#else
 	struct cmd_results *error = NULL;
-	if ((error = checkarg(argc, "tray_padding", EXPECTED_AT_LEAST, 1))) {
+	if ((error = checkarg(argc, cmd_name, EXPECTED_AT_LEAST, 1))) {
 		return error;
 	}
 
 	if (!config->current_bar) {
-		return cmd_results_new(CMD_FAILURE, "tray_padding", "No bar defined.");
+		return cmd_results_new(CMD_FAILURE, cmd_name, "No bar defined.");
 	}
 
-	int padding = atoi(argv[0]);
+	if (argc == 1 || (argc == 2 && strcasecmp("px", argv[1]) == 0)) {
-	if (padding < 0) {
+		char *inv;
-		return cmd_results_new(CMD_INVALID, "tray_padding",
+		uint32_t padding = strtoul(argv[0], &inv, 10);
-				"Invalid padding value %s, minimum is 0", argv[0]);
+		if (*inv == '\0' || strcasecmp(inv, "px") == 0) {
+			config->current_bar->tray_padding = padding;
+			sway_log(L_DEBUG, "Enabling tray padding of %d px on bar: %s", padding, config->current_bar->id);
+			return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+		}
 	}
-
+	return cmd_results_new(CMD_FAILURE, cmd_name,
-	if (argc > 1 && strcasecmp("px", argv[1]) != 0) {
+		"Expected 'tray_padding <padding>[px]'");
-		return cmd_results_new(CMD_INVALID, "tray_padding",
+#endif
-				"Unknown unit %s", argv[1]);
-	}
-	config->current_bar->tray_padding = padding;
-	sway_log(L_DEBUG, "Enabling tray padding of %d px on bar: %s", padding, config->current_bar->id);
-	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 }

sway/config.c

@@ -69,6 +69,10 @@ static void free_bar(struct bar_config *bar) {
 	}
 	free(bar->mode);
 	free(bar->hidden_state);
+#ifdef ENABLE_TRAY
+	free(bar->tray_output);
+	free(bar->icon_theme);
+#endif
 	free(bar->status_command);
 	free(bar->font);
 	free(bar->separator_symbol);
@@ -1386,7 +1390,14 @@ struct bar_config *default_bar_config(void) {
 	bar->separator_symbol = NULL;
 	bar->strip_workspace_numbers = false;
 	bar->binding_mode_indicator = true;
+#ifdef ENABLE_TRAY
+	bar->tray_output = NULL;
+	bar->icon_theme = NULL;
 	bar->tray_padding = 2;
+	bar->activate_button = 0x110; /* BTN_LEFT */
+	bar->context_button = 0x111; /* BTN_RIGHT */
+	bar->secondary_button = 0x112; /* BTN_MIDDLE */
+#endif
 	bar->verbose = false;
 	bar->pid = 0;
 	// set default colors

sway/ipc-json.c

@@ -327,7 +327,22 @@ json_object *ipc_json_describe_bar_config(struct bar_config *bar) {
 
 	json_object *json = json_object_new_object();
 	json_object_object_add(json, "id", json_object_new_string(bar->id));
-	json_object_object_add(json, "tray_output", NULL);
+#ifdef ENABLE_TRAY
+	if (bar->tray_output) {
+		json_object_object_add(json, "tray_output", json_object_new_string(bar->tray_output));
+	} else {
+		json_object_object_add(json, "tray_output", NULL);
+	}
+	if (bar->icon_theme) {
+		json_object_object_add(json, "icon_theme", json_object_new_string(bar->icon_theme));
+	} else {
+		json_object_object_add(json, "icon_theme", NULL);
+	}
+	json_object_object_add(json, "tray_padding", json_object_new_int(bar->tray_padding));
+	json_object_object_add(json, "activate_button", json_object_new_int(bar->activate_button));
+	json_object_object_add(json, "context_button", json_object_new_int(bar->context_button));
+	json_object_object_add(json, "secondary_button", json_object_new_int(bar->secondary_button));
+#endif
 	json_object_object_add(json, "mode", json_object_new_string(bar->mode));
 	json_object_object_add(json, "hidden_state", json_object_new_string(bar->hidden_state));
 	json_object_object_add(json, "modifier", json_object_new_string(get_modifier_name_by_mask(bar->modifier)));

sway/sway-bar.5.txt

@@ -65,6 +65,42 @@ Commands
 **height** <height>::
 	Sets the height of the bar. Default height will match the font size.
 
+Tray
+----
+
+Swaybar provides a system tray where programs such as NetworkManager, VLC,
+Pidgin, etc. can place little icons. The following commands configure
+interaction with the tray or individual icons.
+The _button_ argument in all following commands is a Linux input event code as
+defined in linux/input-event-codes.h. This is because wayland defines button
+codes in this manner.
+
+**activate_button** <button>::
+	Sets the button to be used for the _activate_ (primary click) tray item
+	event. By default is BTN_LEFT (0x110).
+
+**context_button** <button>::
+	Sets the button to be used for the _context menu_ (right click) tray item
+	event. By default is BTN_RIGHT (0x111).
+
+**secondary_button** <button>::
+	Sets the button to be used for the _secondary_ (middle click) tray item
+	event. By default is BTN_MIDDLE (0x112).
+
+**tray_output** none|all|<name>::
+	Sets the output that the tray will appear on or none. Unlike i3bar, swaybar
+	should be able to show icons on any number of bars and outputs without
+	races. Because of this, the default value for this is _all_.
+
+**tray_padding** <px> [px]::
+	Sets the pixel padding of the system tray. This padding will surround the
+	tray on all sides and between each item. The default value for _px_ is 2.
+
+**icon_theme** <name>::
+	Sets the icon theme that sway will look for item icons in. This option has
+	no default value, because sway will always default to the fallback theme,
+	hicolor.
+
 Colors
 ------
 

swaybar/CMakeLists.txt

@@ -5,7 +5,13 @@ include_directories(
 	${PANGO_INCLUDE_DIRS}
 	${JSONC_INCLUDE_DIRS}
 	${XKBCOMMON_INCLUDE_DIRS}
+	${DBUS_INCLUDE_DIRS}
 )
+if (enable-tray)
+	file(GLOB tray
+		tray/*.c
+	)
+endif()
 
 add_executable(swaybar
 	main.c
@@ -14,6 +20,8 @@ add_executable(swaybar
 	bar.c
 	status_line.c
 	ipc.c
+	event_loop.c
+	${tray}
 )
 
 target_link_libraries(swaybar
@@ -24,6 +32,7 @@ target_link_libraries(swaybar
 	${CAIRO_LIBRARIES}
 	${PANGO_LIBRARIES}
 	${JSONC_LIBRARIES}
+	${DBUS_LIBRARIES}
 )
 
 if (WITH_GDK_PIXBUF)
@@ -32,6 +41,8 @@ if (WITH_GDK_PIXBUF)
 	)
 endif()
 
+target_link_libraries(swaybar rt)
+
 install(
 	TARGETS swaybar
 	RUNTIME

swaybar/bar.c

@@ -7,10 +7,17 @@
 #include <sys/wait.h>
 #include <signal.h>
 #include <poll.h>
+#ifdef ENABLE_TRAY
+#include <dbus/dbus.h>
+#include "swaybar/tray/sni_watcher.h"
+#include "swaybar/tray/tray.h"
+#include "swaybar/tray/sni.h"
+#endif
 #include "swaybar/ipc.h"
 #include "swaybar/render.h"
 #include "swaybar/config.h"
 #include "swaybar/status_line.h"
+#include "swaybar/event_loop.h"
 #include "swaybar/bar.h"
 #include "ipc-client.h"
 #include "list.h"
@@ -50,18 +57,39 @@ static void spawn_status_cmd_proc(struct bar *bar) {
 	}
 }
 
+#ifdef ENABLE_TRAY
+static void spawn_xembed_sni_proxy() {
+	pid_t pid = fork();
+	if (pid == 0) {
+		int wstatus;
+		do {
+			pid = fork();
+			if (pid == 0) {
+				execlp("xembedsniproxy", "xembedsniproxy", NULL);
+				_exit(EXIT_FAILURE);
+			}
+			waitpid(pid, &wstatus, 0);
+		} while (!WIFEXITED(wstatus));
+		_exit(EXIT_FAILURE);
+	}
+}
+#endif
+
 struct output *new_output(const char *name) {
 	struct output *output = malloc(sizeof(struct output));
 	output->name = strdup(name);
 	output->window = NULL;
 	output->registry = NULL;
 	output->workspaces = create_list();
+#ifdef ENABLE_TRAY
+	output->items = create_list();
+#endif
 	return output;
 }
 
 static void mouse_button_notify(struct window *window, int x, int y,
 		uint32_t button, uint32_t state_w) {
-	sway_log(L_DEBUG, "Mouse button %d clicked at %d %d %d\n", button, x, y, state_w);
+	sway_log(L_DEBUG, "Mouse button %d clicked at %d %d %d", button, x, y, state_w);
 	if (!state_w) {
 		return;
 	}
@@ -92,6 +120,30 @@ static void mouse_button_notify(struct window *window, int x, int y,
 			break;
 		}
 	}
+
+#ifdef ENABLE_TRAY
+	uint32_t tray_padding = swaybar.config->tray_padding;
+	int tray_width = window->width * window->scale;
+
+	for (int i = 0; i < clicked_output->items->length; ++i) {
+		struct sni_icon_ref *item =
+			 clicked_output->items->items[i];
+		int icon_width = cairo_image_surface_get_width(item->icon);
+
+		tray_width -= tray_padding;
+		if (x <= tray_width && x >= tray_width - icon_width) {
+			if (button == swaybar.config->activate_button) {
+				sni_activate(item->ref, x, y);
+			} else if (button == swaybar.config->context_button) {
+				sni_context_menu(item->ref, x, y);
+			} else if (button == swaybar.config->secondary_button) {
+				sni_secondary(item->ref, x, y);
+			}
+			break;
+		}
+		tray_width -= icon_width;
+	}
+#endif
 }
 
 static void mouse_scroll_notify(struct window *window, enum scroll_direction direction) {
@@ -136,6 +188,9 @@ void bar_setup(struct bar *bar, const char *socket_path, const char *bar_id) {
 	/* initialize bar with default values */
 	bar_init(bar);
 
+	/* Initialize event loop lists */
+	init_event_loop();
+
 	/* connect to sway ipc */
 	bar->ipc_socketfd = ipc_open_socket(socket_path);
 	bar->ipc_event_socketfd = ipc_open_socket(socket_path);
@@ -178,23 +233,54 @@ void bar_setup(struct bar *bar, const char *socket_path, const char *bar_id) {
 	}
 	/* spawn status command */
 	spawn_status_cmd_proc(bar);
+
+#ifdef ENABLE_TRAY
+	// We should have at least one output to serve the tray to
+	if (!swaybar.config->tray_output || strcmp(swaybar.config->tray_output, "none") != 0) {
+		/* Connect to the D-Bus */
+		dbus_init();
+
+		/* Start the SNI watcher */
+		init_sni_watcher();
+
+		/* Start the SNI host */
+		init_tray();
+
+		/* Start xembedsniproxy */
+		spawn_xembed_sni_proxy();
+	}
+#endif
+}
+
+bool dirty = true;
+
+static void respond_ipc(int fd, short mask, void *_bar) {
+	struct bar *bar = (struct bar *)_bar;
+	sway_log(L_DEBUG, "Got IPC event.");
+	dirty = handle_ipc_event(bar);
+}
+
+static void respond_command(int fd, short mask, void *_bar) {
+	struct bar *bar = (struct bar *)_bar;
+	dirty = handle_status_line(bar);
+}
+
+static void respond_output(int fd, short mask, void *_output) {
+	struct output *output = (struct output *)_output;
+	if (wl_display_dispatch(output->registry->display) == -1) {
+		sway_log(L_ERROR, "failed to dispatch wl: %d", errno);
+	}
 }
 
 void bar_run(struct bar *bar) {
-	int pfds = bar->outputs->length + 2;
+	add_event(bar->ipc_event_socketfd, POLLIN, respond_ipc, bar);
-	struct pollfd *pfd = malloc(pfds * sizeof(struct pollfd));
+	add_event(bar->status_read_fd, POLLIN, respond_command, bar);
-	bool dirty = true;
-
-	pfd[0].fd = bar->ipc_event_socketfd;
-	pfd[0].events = POLLIN;
-	pfd[1].fd = bar->status_read_fd;
-	pfd[1].events = POLLIN;
 
 	int i;
 	for (i = 0; i < bar->outputs->length; ++i) {
 		struct output *output = bar->outputs->items[i];
-		pfd[i+2].fd = wl_display_get_fd(output->registry->display);
+		add_event(wl_display_get_fd(output->registry->display),
-		pfd[i+2].events = POLLIN;
+				POLLIN, respond_output, output);
 	}
 
 	while (1) {
@@ -212,29 +298,10 @@ void bar_run(struct bar *bar) {
 
 		dirty = false;
 
-		poll(pfd, pfds, -1);
+		event_loop_poll();
-
+#ifdef ENABLE_TRAY
-		if (pfd[0].revents & POLLIN) {
+		dispatch_dbus();
-			sway_log(L_DEBUG, "Got IPC event.");
+#endif
-			dirty = handle_ipc_event(bar);
-		}
-
-		if (bar->config->status_command && pfd[1].revents & POLLIN) {
-			sway_log(L_DEBUG, "Got update from status command.");
-			dirty = handle_status_line(bar);
-		}
-
-		// dispatch wl_display events
-		for (i = 0; i < bar->outputs->length; ++i) {
-			struct output *output = bar->outputs->items[i];
-			if (pfd[i+2].revents & POLLIN) {
-				if (wl_display_dispatch(output->registry->display) == -1) {
-					sway_log(L_ERROR, "failed to dispatch wl: %d", errno);
-				}
-			} else {
-				wl_display_dispatch_pending(output->registry->display);
-			}
-		}
 	}
 }
 

swaybar/config.c

@@ -48,6 +48,18 @@ struct config *init_config() {
 	/* height */
 	config->height = 0;
 
+#ifdef ENABLE_TRAY
+	config->tray_output = NULL;
+	config->icon_theme = NULL;
+	config->tray_padding = 2;
+	/**
+	 * These constants are used by wayland and are defined in
+	 * linux/input-event-codes.h
+	 */
+	config->activate_button = 0x110; /* BTN_LEFT */
+	config->context_button = 0x111; /* BTN_RIGHT */
+#endif
+
 	/* colors */
 	config->colors.background = 0x000000FF;
 	config->colors.statusline = 0xFFFFFFFF;

swaybar/event_loop.c

@@ -0,0 +1,143 @@
+#define _XOPEN_SOURCE 500
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+#include <strings.h>
+#include <poll.h>
+#include "swaybar/bar.h"
+#include "swaybar/event_loop.h"
+#include "list.h"
+#include "log.h"
+
+struct event_item {
+	void(*cb)(int fd, short mask, void *data);
+	void *data;
+};
+
+struct timer_item {
+	timer_t timer;
+	void(*cb)(timer_t timer, void *data);
+	void *data;
+};
+
+static struct {
+	// The order of each must be kept consistent
+	struct {   /* pollfd array */
+		struct pollfd *items;
+		int capacity;
+		int length;
+	} fds;
+	list_t *items; /* event_item list */
+
+	// Timer list
+	list_t *timers;
+} event_loop;
+
+void add_timer(timer_t timer,
+		void(*cb)(timer_t timer, void *data),
+		void *data) {
+
+	struct timer_item *item = malloc(sizeof(struct timer_item));
+	item->timer = timer;
+	item->cb = cb;
+	item->data = data;
+
+	list_add(event_loop.timers, item);
+}
+
+void add_event(int fd, short mask,
+		void(*cb)(int fd, short mask, void *data), void *data) {
+
+	struct pollfd pollfd = {
+		fd,
+		mask,
+		0,
+	};
+
+	// Resize
+	if (event_loop.fds.length == event_loop.fds.capacity) {
+		event_loop.fds.capacity += 10;
+		event_loop.fds.items = realloc(event_loop.fds.items,
+			sizeof(struct pollfd) * event_loop.fds.capacity);
+	}
+
+	event_loop.fds.items[event_loop.fds.length++] = pollfd;
+
+	struct event_item *item = malloc(sizeof(struct event_item));
+	item->cb = cb;
+	item->data = data;
+
+	list_add(event_loop.items, item);
+
+	return;
+}
+
+bool remove_event(int fd) {
+	int index = -1;
+	for (int i = 0; i < event_loop.fds.length; ++i) {
+		if (event_loop.fds.items[i].fd == fd) {
+			index = i;
+		}
+	}
+	if (index != -1) {
+		free(event_loop.items->items[index]);
+
+		--event_loop.fds.length;
+		memmove(&event_loop.fds.items[index], &event_loop.fds.items[index + 1],
+				sizeof(struct pollfd) * event_loop.fds.length - index);
+
+		list_del(event_loop.items, index);
+		return true;
+	} else {
+		return false;
+	}
+}
+
+static int timer_item_timer_cmp(const void *_timer_item, const void *_timer) {
+	const struct timer_item *timer_item = _timer_item;
+	const timer_t *timer = _timer;
+	if (timer_item->timer == timer) {
+		return 0;
+	} else {
+		return -1;
+	}
+}
+bool remove_timer(timer_t timer) {
+	int index = list_seq_find(event_loop.timers, timer_item_timer_cmp, &timer);
+	if (index != -1) {
+		list_del(event_loop.timers, index);
+		return true;
+	}
+	return false;
+}
+
+void event_loop_poll() {
+	poll(event_loop.fds.items, event_loop.fds.length, -1);
+
+	for (int i = 0; i < event_loop.fds.length; ++i) {
+		struct pollfd pfd = event_loop.fds.items[i];
+		struct event_item *item = (struct event_item *)event_loop.items->items[i];
+
+		if (pfd.revents & pfd.events) {
+			item->cb(pfd.fd, pfd.revents, item->data);
+		}
+	}
+
+	// check timers
+	// not tested, but seems to work
+	for (int i = 0; i < event_loop.timers->length; ++i) {
+		struct timer_item *item = event_loop.timers->items[i];
+		int overrun = timer_getoverrun(item->timer);
+		if (overrun && overrun != -1) {
+			item->cb(item->timer, item->data);
+		}
+	}
+}
+
+void init_event_loop() {
+	event_loop.fds.length = 0;
+	event_loop.fds.capacity = 10;
+	event_loop.fds.items = malloc(event_loop.fds.capacity * sizeof(struct pollfd));
+	event_loop.items = create_list();
+	event_loop.timers = create_list();
+}

swaybar/ipc.c

@@ -19,11 +19,19 @@ void ipc_send_workspace_command(const char *workspace_name) {
 
 static void ipc_parse_config(struct config *config, const char *payload) {
 	json_object *bar_config = json_tokener_parse(payload);
-	json_object *tray_output, *mode, *hidden_bar, *position, *status_command;
+	json_object *markup, *mode, *hidden_bar, *position, *status_command;
 	json_object *font, *bar_height, *wrap_scroll, *workspace_buttons, *strip_workspace_numbers;
 	json_object *binding_mode_indicator, *verbose, *colors, *sep_symbol, *outputs;
-	json_object *markup;
+#ifdef ENABLE_TRAY
+	json_object *tray_output, *icon_theme, *tray_padding, *activate_button, *context_button;
+	json_object *secondary_button;
 	json_object_object_get_ex(bar_config, "tray_output", &tray_output);
+	json_object_object_get_ex(bar_config, "icon_theme", &icon_theme);
+	json_object_object_get_ex(bar_config, "tray_padding", &tray_padding);
+	json_object_object_get_ex(bar_config, "activate_button", &activate_button);
+	json_object_object_get_ex(bar_config, "context_button", &context_button);
+	json_object_object_get_ex(bar_config, "secondary_button", &secondary_button);
+#endif
 	json_object_object_get_ex(bar_config, "mode", &mode);
 	json_object_object_get_ex(bar_config, "hidden_bar", &hidden_bar);
 	json_object_object_get_ex(bar_config, "position", &position);
@@ -83,6 +91,34 @@ static void ipc_parse_config(struct config *config, const char *payload) {
 		config->pango_markup = json_object_get_boolean(markup);
 	}
 
+#ifdef ENABLE_TRAY
+	if (tray_output) {
+		free(config->tray_output);
+		config->tray_output = strdup(json_object_get_string(tray_output));
+	}
+
+	if (icon_theme) {
+		free(config->icon_theme);
+		config->icon_theme = strdup(json_object_get_string(icon_theme));
+	}
+
+	if (tray_padding) {
+		config->tray_padding = json_object_get_int(tray_padding);
+	}
+
+	if (activate_button) {
+		config->activate_button = json_object_get_int(activate_button);
+	}
+
+	if (context_button) {
+		config->context_button = json_object_get_int(context_button);
+	}
+
+	if (secondary_button) {
+		config->secondary_button = json_object_get_int(secondary_button);
+	}
+#endif
+
 	// free previous outputs list
 	int i;
 	for (i = 0; i < config->outputs->length; ++i) {

swaybar/render.c

@@ -8,6 +8,10 @@
 #include "swaybar/config.h"
 #include "swaybar/status_line.h"
 #include "swaybar/render.h"
+#ifdef ENABLE_TRAY
+#include "swaybar/tray/tray.h"
+#include "swaybar/tray/sni.h"
+#endif
 #include "log.h"
 
 
@@ -297,6 +301,72 @@ void render(struct output *output, struct config *config, struct status_line *li
 	}
 	cairo_paint(cairo);
 
+#ifdef ENABLE_TRAY
+	// Tray icons
+	uint32_t tray_padding = config->tray_padding;
+	unsigned int tray_width = window->width * window->scale;
+	const int item_size = (window->height * window->scale) - (2 * tray_padding);
+
+	if (item_size < 0) {
+		// Can't render items if the padding is too large
+		goto no_tray;
+	}
+
+	if (config->tray_output && strcmp(config->tray_output, output->name) != 0) {
+		goto no_tray;
+	}
+
+	for (int i = 0; i < tray->items->length; ++i) {
+		struct StatusNotifierItem *item =
+			tray->items->items[i];
+		if (!item->image) {
+			continue;
+		}
+
+		struct sni_icon_ref *render_item = NULL;
+		int j;
+		for (j = i; j < output->items->length; ++j) {
+			struct sni_icon_ref *ref =
+				output->items->items[j];
+			if (ref->ref == item) {
+				render_item = ref;
+				break;
+			} else {
+				sni_icon_ref_free(ref);
+				list_del(output->items, j);
+			}
+		}
+
+		if (!render_item) {
+			render_item = sni_icon_ref_create(item, item_size);
+			list_add(output->items, render_item);
+		} else if (item->dirty) {
+			// item needs re-render
+			sni_icon_ref_free(render_item);
+			output->items->items[j] = render_item =
+				sni_icon_ref_create(item, item_size);
+		}
+
+		tray_width -= tray_padding;
+		tray_width -= item_size;
+
+		cairo_set_source_surface(cairo, render_item->icon, tray_width, tray_padding);
+		cairo_rectangle(cairo, tray_width, tray_padding, item_size, item_size);
+		cairo_fill(cairo);
+
+		item->dirty = false;
+	}
+
+
+	if (tray_width != window->width * window->scale) {
+		tray_width -= tray_padding;
+	}
+
+no_tray:
+#else
+	const int tray_width = window->width * window->scale;
+#endif
+
 	// Command output
 	if (is_focused) {
 		cairo_set_source_u32(cairo, config->colors.focused_statusline);
@@ -309,12 +379,11 @@ void render(struct output *output, struct config *config, struct status_line *li
 	if (line->protocol == TEXT) {
 		get_text_size(window->cairo, window->font, &width, &height,
 				window->scale, config->pango_markup, "%s", line->text_line);
-		cairo_move_to(cairo, (window->width * window->scale)
+		cairo_move_to(cairo, tray_width - margin - width, margin);
-				- margin - width, margin);
 		pango_printf(window->cairo, window->font, window->scale,
 				config->pango_markup, "%s", line->text_line);
 	} else if (line->protocol == I3BAR && line->block_line) {
-		double pos = (window->width * window->scale) - 0.5;
+		double pos = tray_width - 0.5;
 		bool edge = true;
 		for (i = line->block_line->length - 1; i >= 0; --i) {
 			struct status_block *block = line->block_line->items[i];

swaybar/tray/dbus.c

@@ -0,0 +1,189 @@
+#define _XOPEN_SOURCE 500
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <poll.h>
+#include <signal.h>
+#include <time.h>
+#include <dbus/dbus.h>
+#include "swaybar/tray/dbus.h"
+#include "swaybar/event_loop.h"
+#include "log.h"
+
+DBusConnection *conn = NULL;
+
+static void dispatch_watch(int fd, short mask, void *data) {
+	sway_log(L_DEBUG, "Dispatching watch");
+	DBusWatch *watch = data;
+
+	if (!dbus_watch_get_enabled(watch)) {
+		return;
+	}
+
+	uint32_t flags = 0;
+
+	if (mask & POLLIN) {
+		flags |= DBUS_WATCH_READABLE;
+	} if (mask & POLLOUT) {
+		flags |= DBUS_WATCH_WRITABLE;
+	} if (mask & POLLHUP) {
+		flags |= DBUS_WATCH_HANGUP;
+	} if (mask & POLLERR) {
+		flags |= DBUS_WATCH_ERROR;
+	}
+
+	dbus_watch_handle(watch, flags);
+}
+
+static dbus_bool_t add_watch(DBusWatch *watch, void *_data) {
+	if (!dbus_watch_get_enabled(watch)) {
+		// Watch should not be polled
+		return TRUE;
+	}
+
+	short mask = 0;
+	uint32_t flags = dbus_watch_get_flags(watch);
+
+	if (flags & DBUS_WATCH_READABLE) {
+		mask |= POLLIN;
+	} if (flags & DBUS_WATCH_WRITABLE) {
+		mask |= POLLOUT;
+	}
+
+	int fd = dbus_watch_get_unix_fd(watch);
+
+	sway_log(L_DEBUG, "Adding DBus watch fd: %d", fd);
+	add_event(fd, mask, dispatch_watch, watch);
+
+	return TRUE;
+}
+
+static void remove_watch(DBusWatch *watch, void *_data) {
+	int fd = dbus_watch_get_unix_fd(watch);
+
+	remove_event(fd);
+}
+
+static void dispatch_timeout(timer_t timer, void *data) {
+	sway_log(L_DEBUG, "Dispatching DBus timeout");
+	DBusTimeout *timeout = data;
+
+	if (dbus_timeout_get_enabled(timeout)) {
+		dbus_timeout_handle(timeout);
+	}
+}
+
+static dbus_bool_t add_timeout(DBusTimeout *timeout, void *_data) {
+	if (!dbus_timeout_get_enabled(timeout)) {
+		return TRUE;
+	}
+
+	timer_t *timer = malloc(sizeof(timer_t));
+	if (!timer) {
+		sway_log(L_ERROR, "Cannot allocate memory");
+		return FALSE;
+	}
+	struct sigevent ev = {
+		.sigev_notify = SIGEV_NONE,
+	};
+
+	if (timer_create(CLOCK_MONOTONIC, &ev, timer)) {
+		sway_log(L_ERROR, "Could not create DBus timer");
+		return FALSE;
+	}
+
+	int interval = dbus_timeout_get_interval(timeout);
+	int interval_sec = interval / 1000;
+	int interval_msec = (interval_sec * 1000) - interval;
+
+	struct timespec period = {
+		(time_t) interval_sec,
+		((long) interval_msec) * 1000 * 1000,
+	};
+	struct itimerspec time = {
+		period,
+		period,
+	};
+
+	timer_settime(*timer, 0, &time, NULL);
+
+	dbus_timeout_set_data(timeout, timer, free);
+
+	sway_log(L_DEBUG, "Adding DBus timeout. Interval: %ds %dms", interval_sec, interval_msec);
+	add_timer(*timer, dispatch_timeout, timeout);
+
+	return TRUE;
+}
+static void remove_timeout(DBusTimeout *timeout, void *_data) {
+	timer_t *timer = (timer_t *) dbus_timeout_get_data(timeout);
+	sway_log(L_DEBUG, "Removing DBus timeout.");
+
+	if (timer) {
+		remove_timer(*timer);
+	}
+}
+
+static bool should_dispatch = true;
+
+static void dispatch_status(DBusConnection *connection, DBusDispatchStatus new_status,
+		void *_data) {
+	if (new_status == DBUS_DISPATCH_DATA_REMAINS) {
+		should_dispatch = true;
+	}
+}
+
+/* Public functions below */
+
+void dispatch_dbus() {
+	if (!should_dispatch) {
+		return;
+	}
+
+	DBusDispatchStatus status;
+
+	do {
+		status = dbus_connection_dispatch(conn);
+	} while (status == DBUS_DISPATCH_DATA_REMAINS);
+
+	if (status != DBUS_DISPATCH_COMPLETE) {
+		sway_log(L_ERROR, "Cannot dispatch dbus events: %d", status);
+	}
+
+	should_dispatch = false;
+}
+
+int dbus_init() {
+	DBusError error;
+	dbus_error_init(&error);
+
+	conn = dbus_bus_get(DBUS_BUS_SESSION, &error);
+	dbus_connection_set_exit_on_disconnect(conn, FALSE);
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "Cannot get bus connection: %s\n", error.message);
+		conn = NULL;
+		return -1;
+	}
+
+	sway_log(L_INFO, "Unique name: %s\n", dbus_bus_get_unique_name(conn));
+
+	// Will be called if dispatch status changes
+	dbus_connection_set_dispatch_status_function(conn, dispatch_status, NULL, NULL);
+
+	if (!dbus_connection_set_watch_functions(conn, add_watch, remove_watch,
+			NULL, NULL, NULL)) {
+		dbus_connection_set_watch_functions(conn, NULL, NULL, NULL, NULL, NULL);
+		sway_log(L_ERROR, "Failed to activate DBUS watch functions");
+		return -1;
+	}
+
+	if (!dbus_connection_set_timeout_functions(conn, add_timeout, remove_timeout,
+			NULL, NULL, NULL)) {
+		dbus_connection_set_watch_functions(conn, NULL, NULL, NULL, NULL, NULL);
+		dbus_connection_set_timeout_functions(conn, NULL, NULL, NULL, NULL, NULL);
+		sway_log(L_ERROR, "Failed to activate DBUS timeout functions");
+		return -1;
+	}
+
+	return 0;
+}

swaybar/tray/icon.c

@@ -0,0 +1,404 @@
+#define _XOPEN_SOURCE 500
+#define _POSIX_C_SOURCE 200809L
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <limits.h>
+#include "swaybar/tray/icon.h"
+#include "swaybar/bar.h"
+#include "swaybar/config.h"
+#include "stringop.h"
+#include "log.h"
+
+/**
+ * REVIEW:
+ * This file repeats lots of "costly" operations that are the same for every
+ * icon. It's possible to create a dictionary or some other structure to cache
+ * these, though it may complicate things somewhat.
+ *
+ * Also parsing (index.theme) is currently pretty messy, so that could be made
+ * much better as well. Over all, things work, but are not optimal.
+ */
+
+/* Finds all themes that the given theme inherits */
+static list_t *find_inherits(const char *theme_dir) {
+	const char inherits[] = "Inherits";
+	const char index_name[] = "index.theme";
+	list_t *themes = create_list();
+	FILE *index = NULL;
+	char *path = malloc(strlen(theme_dir) + sizeof(index_name));
+	if (!path) {
+		goto fail;
+	}
+	if (!themes) {
+		goto fail;
+	}
+
+	strcpy(path, theme_dir);
+	strcat(path, index_name);
+
+	index = fopen(path, "r");
+	if (!index) {
+		goto fail;
+	}
+
+	char *buf = NULL;
+	size_t n = 0;
+	while (!feof(index)) {
+		getline(&buf, &n, index);
+		if (n <= sizeof(inherits) + 1) {
+			continue;
+		}
+		if (strncmp(inherits, buf, sizeof(inherits) - 1) == 0) {
+			char *themestr = buf + sizeof(inherits);
+			themes = split_string(themestr, ",");
+			break;
+		}
+	}
+	free(buf);
+
+fail:
+	free(path);
+	if (index) {
+		fclose(index);
+	}
+	return themes;
+}
+
+static bool isdir(const char *path) {
+	struct stat statbuf;
+	if (stat(path, &statbuf) != -1) {
+		if (S_ISDIR(statbuf.st_mode)) {
+			return true;
+		}
+	}
+	return false;
+
+}
+
+/**
+ * Returns the directory of a given theme if it exists.
+ * The returned pointer must be freed.
+ */
+static char *find_theme_dir(const char *theme) {
+	char *basedir;
+	char *icon_dir;
+
+	if (!theme) {
+		return NULL;
+	}
+
+	if (!(icon_dir = malloc(1024))) {
+		sway_log(L_ERROR, "Out of memory!");
+		goto fail;
+	}
+
+	if ((basedir = getenv("HOME"))) {
+		if (snprintf(icon_dir, 1024, "%s/.icons/%s", basedir, theme) >= 1024) {
+			sway_log(L_ERROR, "Path too long to render");
+			// XXX perhaps just goto trying in /usr/share? This
+			// shouldn't happen anyway, but might with a long global
+			goto fail;
+		}
+
+		if (isdir(icon_dir)) {
+			return icon_dir;
+		}
+	}
+
+	if ((basedir = getenv("XDG_DATA_DIRS"))) {
+		if (snprintf(icon_dir, 1024, "%s/icons/%s", basedir, theme) >= 1024) {
+			sway_log(L_ERROR, "Path too long to render");
+			// ditto
+			goto fail;
+		}
+
+		if (isdir(icon_dir)) {
+			return icon_dir;
+		}
+	}
+
+	// Spec says use "/usr/share/pixmaps/", but I see everything in
+	// "/usr/share/icons/" look it both, I suppose.
+	if (snprintf(icon_dir, 1024, "/usr/share/pixmaps/%s", theme) >= 1024) {
+		sway_log(L_ERROR, "Path too long to render");
+		goto fail;
+	}
+	if (isdir(icon_dir)) {
+		return icon_dir;
+	}
+
+	if (snprintf(icon_dir, 1024, "/usr/share/icons/%s", theme) >= 1024) {
+		sway_log(L_ERROR, "Path too long to render");
+		goto fail;
+	}
+	if (isdir(icon_dir)) {
+		return icon_dir;
+	}
+
+fail:
+	free(icon_dir);
+	sway_log(L_ERROR, "Could not find dir for theme: %s", theme);
+	return NULL;
+}
+
+/**
+ * Returns all theme dirs needed to be looked in for an icon.
+ * Does not check for duplicates
+ */
+static list_t *find_all_theme_dirs(const char *theme) {
+	list_t *dirs = create_list();
+	if (!dirs) {
+		return NULL;
+	}
+	char *dir = find_theme_dir(theme);
+	if (dir) {
+		list_add(dirs, dir);
+		list_t *inherits = find_inherits(dir);
+		list_cat(dirs, inherits);
+		list_free(inherits);
+	}
+	dir = find_theme_dir("hicolor");
+	if (dir) {
+		list_add(dirs, dir);
+	}
+
+	return dirs;
+}
+
+struct subdir {
+	int size;
+	char name[];
+};
+
+static int subdir_str_cmp(const void *_subdir, const void *_str) {
+	const struct subdir *subdir = _subdir;
+	const char *str = _str;
+	return strcmp(subdir->name, str);
+}
+/**
+ * Helper to find_subdirs. Acts similar to `split_string(subdirs, ",")` but
+ * generates a list of struct subdirs
+ */
+static list_t *split_subdirs(char *subdir_str) {
+	list_t *subdir_list = create_list();
+	char *copy = strdup(subdir_str);
+	if (!subdir_list || !copy) {
+		list_free(subdir_list);
+		free(copy);
+		return NULL;
+	}
+
+	char *token;
+	token = strtok(copy, ",");
+	while(token) {
+		int len = strlen(token) + 1;
+		struct subdir *subdir =
+			malloc(sizeof(struct subdir) + sizeof(char [len]));
+		if (!subdir) {
+			// Return what we have
+			return subdir_list;
+		}
+		subdir->size = 0;
+		strcpy(subdir->name, token);
+
+		list_add(subdir_list, subdir);
+
+		token = strtok(NULL, ",");
+	}
+	free(copy);
+
+	return subdir_list;
+}
+/**
+ * Returns a list of all subdirectories of a theme.
+ * Take note: the subdir names are all relative to `theme_dir` and must be
+ * combined with it to form a valid directory.
+ *
+ * Each member of the list is of type (struct subdir *) this struct contains
+ * the name of the subdir, along with size information. These must be freed
+ * bye the caller.
+ *
+ * This currently ignores min and max sizes of icons.
+ */
+static list_t* find_theme_subdirs(const char *theme_dir) {
+	const char index_name[] = "/index.theme";
+	list_t *dirs = NULL;
+	char *path = malloc(strlen(theme_dir) + sizeof(index_name));
+	FILE *index = NULL;
+	if (!path) {
+		sway_log(L_ERROR, "Failed to allocate memory");
+		goto fail;
+	}
+
+	strcpy(path, theme_dir);
+	strcat(path, index_name);
+
+	index = fopen(path, "r");
+	if (!index) {
+		sway_log(L_ERROR, "Could not open file: %s", path);
+		goto fail;
+	}
+
+	char *buf = NULL;
+	size_t n = 0;
+	while (!feof(index)) {
+		const char directories[] = "Directories";
+		getline(&buf, &n, index);
+		if (n <= sizeof(directories) + 1) {
+			continue;
+		}
+		if (strncmp(directories, buf, sizeof(directories) - 1) == 0) {
+			char *dirstr = buf + sizeof(directories);
+			dirs = split_subdirs(dirstr);
+			break;
+		}
+	}
+	// Now, find the size of each dir
+	struct subdir *current_subdir = NULL;
+	while (!feof(index)) {
+		const char size[] = "Size";
+		getline(&buf, &n, index);
+
+		if (buf[0] == '[') {
+			int len = strlen(buf);
+			if (buf[len-1] == '\n') {
+				len--;
+			}
+			// replace ']'
+			buf[len-1] = '\0';
+
+			int index;
+			if ((index = list_seq_find(dirs, subdir_str_cmp, buf+1)) != -1) {
+				current_subdir = (dirs->items[index]);
+			}
+		}
+
+		if (strncmp(size, buf, sizeof(size) - 1) == 0) {
+			if (current_subdir) {
+				current_subdir->size = atoi(buf + sizeof(size));
+			}
+		}
+	}
+	free(buf);
+fail:
+	free(path);
+	if (index) {
+		fclose(index);
+	}
+	return dirs;
+}
+
+/* Returns the file of an icon given its name and size */
+static char *find_icon_file(const char *name, int size) {
+	int namelen = strlen(name);
+	list_t *dirs = find_all_theme_dirs(swaybar.config->icon_theme);
+	if (!dirs) {
+		return NULL;
+	}
+	int min_size_diff = INT_MAX;
+	char *current_file = NULL;
+
+	for (int i = 0; i < dirs->length; ++i) {
+		char *dir = dirs->items[i];
+		list_t *subdirs = find_theme_subdirs(dir);
+
+		if (!subdirs) {
+			continue;
+		}
+
+		for (int i = 0; i < subdirs->length; ++i) {
+			struct subdir *subdir = subdirs->items[i];
+
+			// Only use an unsized if we don't already have a
+			// canidate this should probably change to allow svgs
+			if (!subdir->size && current_file) {
+				continue;
+			}
+
+			int size_diff = abs(size - subdir->size);
+
+			if (size_diff >= min_size_diff) {
+				continue;
+			}
+
+			char *path = malloc(strlen(subdir->name) + strlen(dir) + 2);
+
+			strcpy(path, dir);
+			path[strlen(dir)] = '/';
+			strcpy(path + strlen(dir) + 1, subdir->name);
+
+			DIR *icons = opendir(path);
+			if (!icons) {
+				free(path);
+				continue;
+			}
+
+			struct dirent *direntry;
+			while ((direntry = readdir(icons)) != NULL) {
+				int len = strlen(direntry->d_name);
+				if (len <= namelen + 2) { //must have some ext
+					continue;
+				}
+				if (strncmp(direntry->d_name, name, namelen) == 0) {
+					char *ext = direntry->d_name + namelen + 1;
+#ifdef WITH_GDK_PIXBUF
+					if (strcmp(ext, "png") == 0 ||
+							strcmp(ext, "xpm") == 0 ||
+							strcmp(ext, "svg") == 0) {
+#else
+					if (strcmp(ext, "png") == 0) {
+#endif
+						free(current_file);
+						char *icon_path = malloc(strlen(path) + len + 2);
+
+						strcpy(icon_path, path);
+						icon_path[strlen(path)] = '/';
+						strcpy(icon_path + strlen(path) + 1, direntry->d_name);
+						current_file = icon_path;
+						min_size_diff = size_diff;
+					}
+				}
+			}
+			free(path);
+			closedir(icons);
+		}
+		free_flat_list(subdirs);
+	}
+	free_flat_list(dirs);
+
+	return current_file;
+}
+
+cairo_surface_t *find_icon(const char *name, int size) {
+	char *image_path = find_icon_file(name, size);
+	if (image_path == NULL) {
+		return NULL;
+	}
+
+	cairo_surface_t *image = NULL;
+#ifdef WITH_GDK_PIXBUF
+	GError *err = NULL;
+	GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file(image_path, &err);
+	if (!pixbuf) {
+		sway_log(L_ERROR, "Failed to load icon image: %s", err->message);
+	}
+	image = gdk_cairo_image_surface_create_from_pixbuf(pixbuf);
+	g_object_unref(pixbuf);
+#else
+	// TODO make svg work? cairo supports it. maybe remove gdk alltogether
+	image = cairo_image_surface_create_from_png(image_path);
+#endif //WITH_GDK_PIXBUF
+	if (!image) {
+		sway_log(L_ERROR, "Could not read icon image");
+		return NULL;
+	}
+
+	free(image_path);
+	return image;
+}

swaybar/tray/sni.c

@@ -0,0 +1,463 @@
+#define _XOPEN_SOURCE 500
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdbool.h>
+#include <dbus/dbus.h>
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include "swaybar/tray/dbus.h"
+#include "swaybar/tray/sni.h"
+#include "swaybar/tray/icon.h"
+#include "swaybar/bar.h"
+#include "client/cairo.h"
+#include "log.h"
+
+// Not sure what this is but cairo needs it.
+static const cairo_user_data_key_t cairo_user_data_key;
+
+struct sni_icon_ref *sni_icon_ref_create(struct StatusNotifierItem *item,
+		int height) {
+	struct sni_icon_ref *sni_ref = malloc(sizeof(struct sni_icon_ref));
+	if (!sni_ref) {
+		return NULL;
+	}
+	sni_ref->icon = cairo_image_surface_scale(item->image, height, height);
+	sni_ref->ref = item;
+
+	return sni_ref;
+}
+
+void sni_icon_ref_free(struct sni_icon_ref *sni_ref) {
+	if (!sni_ref) {
+		return;
+	}
+	cairo_surface_destroy(sni_ref->icon);
+	free(sni_ref);
+}
+
+/* Gets the pixmap of an icon */
+static void reply_icon(DBusPendingCall *pending, void *_data) {
+	struct StatusNotifierItem *item = _data;
+
+	DBusMessage *reply = dbus_pending_call_steal_reply(pending);
+
+	if (!reply) {
+		sway_log(L_ERROR, "Did not get reply");
+		goto bail;
+	}
+
+	int message_type = dbus_message_get_type(reply);
+
+	if (message_type == DBUS_MESSAGE_TYPE_ERROR) {
+		char *msg;
+
+		dbus_message_get_args(reply, NULL,
+				DBUS_TYPE_STRING, &msg,
+				DBUS_TYPE_INVALID);
+
+		sway_log(L_ERROR, "Message is error: %s", msg);
+		goto bail;
+	}
+
+	DBusMessageIter iter;
+	DBusMessageIter variant; /* v[a(iiay)] */
+	DBusMessageIter array; /* a(iiay) */
+	DBusMessageIter d_struct; /* (iiay) */
+	DBusMessageIter icon; /* ay */
+
+	dbus_message_iter_init(reply, &iter);
+
+	// Each if here checks the types above before recursing
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT) {
+		sway_log(L_ERROR, "Relpy type incorrect");
+		sway_log(L_ERROR, "Should be \"v\", is \"%s\"",
+				dbus_message_iter_get_signature(&iter));
+		goto bail;
+	}
+	dbus_message_iter_recurse(&iter, &variant);
+
+	if (strcmp("a(iiay)", dbus_message_iter_get_signature(&variant)) != 0) {
+		sway_log(L_ERROR, "Relpy type incorrect");
+		sway_log(L_ERROR, "Should be \"a(iiay)\", is \"%s\"",
+				dbus_message_iter_get_signature(&variant));
+		goto bail;
+	}
+
+	if (dbus_message_iter_get_element_count(&variant) == 0) {
+		// Can't recurse if there are no items
+		sway_log(L_INFO, "Item has no icon");
+		goto bail;
+	}
+	dbus_message_iter_recurse(&variant, &array);
+
+	dbus_message_iter_recurse(&array, &d_struct);
+
+	int width;
+	dbus_message_iter_get_basic(&d_struct, &width);
+	dbus_message_iter_next(&d_struct);
+
+	int height;
+	dbus_message_iter_get_basic(&d_struct, &height);
+	dbus_message_iter_next(&d_struct);
+
+	int len = dbus_message_iter_get_element_count(&d_struct);
+
+	if (!len) {
+		sway_log(L_ERROR, "No icon data");
+		goto bail;
+	}
+
+	// Also implies len % 4 == 0, useful below
+	if (len != width * height * 4) {
+		sway_log(L_ERROR, "Incorrect array size passed");
+		goto bail;
+	}
+
+	dbus_message_iter_recurse(&d_struct, &icon);
+
+	int stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width);
+	// FIXME support a variable stride
+	// (works on my machine though for all tested widths)
+	if (!sway_assert(stride == width * 4, "Stride must be equal to byte length")) {
+		goto bail;
+	}
+
+	// Data is by reference, no need to free
+	uint8_t *message_data;
+	dbus_message_iter_get_fixed_array(&icon, &message_data, &len);
+
+	uint8_t *image_data = malloc(stride * height);
+	if (!image_data) {
+		sway_log(L_ERROR, "Could not allocate memory for icon");
+		goto bail;
+	}
+
+	// Transform from network byte order to host byte order
+	// Assumptions are safe because the equality above
+	uint32_t *network = (uint32_t *) message_data;
+	uint32_t *host = (uint32_t *)image_data;
+	for (int i = 0; i < width * height; ++i) {
+		host[i] = ntohl(network[i]);
+	}
+
+	cairo_surface_t *image = cairo_image_surface_create_for_data(
+			image_data, CAIRO_FORMAT_ARGB32,
+			width, height, stride);
+
+	if (image) {
+		if (item->image) {
+			cairo_surface_destroy(item->image);
+		}
+		item->image = image;
+		// Free the image data on surface destruction
+		cairo_surface_set_user_data(image,
+				&cairo_user_data_key,
+				image_data,
+				free);
+		item->dirty = true;
+		dirty = true;
+
+		dbus_message_unref(reply);
+		return;
+	} else {
+		sway_log(L_ERROR, "Could not create image surface");
+		free(image_data);
+	}
+
+bail:
+	if (reply) {
+		dbus_message_unref(reply);
+	}
+	sway_log(L_ERROR, "Could not get icon from item");
+	return;
+}
+static void send_icon_msg(struct StatusNotifierItem *item) {
+	DBusPendingCall *pending;
+	DBusMessage *message = dbus_message_new_method_call(
+			item->name,
+			"/StatusNotifierItem",
+			"org.freedesktop.DBus.Properties",
+			"Get");
+	const char *iface;
+	if (item->kde_special_snowflake) {
+		iface = "org.kde.StatusNotifierItem";
+	} else {
+		iface = "org.freedesktop.StatusNotifierItem";
+	}
+	const char *prop = "IconPixmap";
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_STRING, &iface,
+			DBUS_TYPE_STRING, &prop,
+			DBUS_TYPE_INVALID);
+
+	bool status =
+		dbus_connection_send_with_reply(conn, message, &pending, -1);
+
+	dbus_message_unref(message);
+
+	if (!(pending || status)) {
+		sway_log(L_ERROR, "Could not get item icon");
+		return;
+	}
+
+	dbus_pending_call_set_notify(pending, reply_icon, item, NULL);
+}
+
+/* Get an icon by its name */
+static void reply_icon_name(DBusPendingCall *pending, void *_data) {
+	struct StatusNotifierItem *item = _data;
+
+	DBusMessage *reply = dbus_pending_call_steal_reply(pending);
+
+	if (!reply) {
+		sway_log(L_INFO, "Got no icon name reply from item");
+		goto bail;
+	}
+
+	int message_type = dbus_message_get_type(reply);
+
+	if (message_type == DBUS_MESSAGE_TYPE_ERROR) {
+		char *msg;
+
+		dbus_message_get_args(reply, NULL,
+				DBUS_TYPE_STRING, &msg,
+				DBUS_TYPE_INVALID);
+
+		sway_log(L_INFO, "Could not get icon name: %s", msg);
+		goto bail;
+	}
+
+	DBusMessageIter iter; /* v[s] */
+	DBusMessageIter variant; /* s */
+
+	dbus_message_iter_init(reply, &iter);
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT) {
+		sway_log(L_ERROR, "Relpy type incorrect");
+		sway_log(L_ERROR, "Should be \"v\", is \"%s\"",
+				dbus_message_iter_get_signature(&iter));
+		goto bail;
+	}
+	dbus_message_iter_recurse(&iter, &variant);
+
+
+	if (dbus_message_iter_get_arg_type(&variant) != DBUS_TYPE_STRING) {
+		sway_log(L_ERROR, "Relpy type incorrect");
+		sway_log(L_ERROR, "Should be \"s\", is \"%s\"",
+				dbus_message_iter_get_signature(&iter));
+		goto bail;
+	}
+
+	char *icon_name;
+	dbus_message_iter_get_basic(&variant, &icon_name);
+
+	cairo_surface_t *image = find_icon(icon_name, 256);
+
+	if (image) {
+		sway_log(L_DEBUG, "Icon for %s found with size %d", icon_name,
+				cairo_image_surface_get_width(image));
+		if (item->image) {
+			cairo_surface_destroy(item->image);
+		}
+		item->image = image;
+		item->dirty = true;
+		dirty = true;
+
+		dbus_message_unref(reply);
+		return;
+	}
+
+bail:
+	if (reply) {
+		dbus_message_unref(reply);
+	}
+	// Now try the pixmap
+	send_icon_msg(item);
+	return;
+}
+static void send_icon_name_msg(struct StatusNotifierItem *item) {
+	DBusPendingCall *pending;
+	DBusMessage *message = dbus_message_new_method_call(
+			item->name,
+			"/StatusNotifierItem",
+			"org.freedesktop.DBus.Properties",
+			"Get");
+	const char *iface;
+	if (item->kde_special_snowflake) {
+		iface = "org.kde.StatusNotifierItem";
+	} else {
+		iface = "org.freedesktop.StatusNotifierItem";
+	}
+	const char *prop = "IconName";
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_STRING, &iface,
+			DBUS_TYPE_STRING, &prop,
+			DBUS_TYPE_INVALID);
+
+	bool status =
+		dbus_connection_send_with_reply(conn, message, &pending, -1);
+
+	dbus_message_unref(message);
+
+	if (!(pending || status)) {
+		sway_log(L_ERROR, "Could not get item icon name");
+		return;
+	}
+
+	dbus_pending_call_set_notify(pending, reply_icon_name, item, NULL);
+}
+
+void get_icon(struct StatusNotifierItem *item) {
+	send_icon_name_msg(item);
+}
+
+void sni_activate(struct StatusNotifierItem *item, uint32_t x, uint32_t y) {
+	const char *iface =
+		(item->kde_special_snowflake ? "org.kde.StatusNotifierItem"
+		 : "org.freedesktop.StatusNotifierItem");
+	DBusMessage *message = dbus_message_new_method_call(
+			item->name,
+			"/StatusNotifierItem",
+			iface,
+			"Activate");
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_INT32, &x,
+			DBUS_TYPE_INT32, &y,
+			DBUS_TYPE_INVALID);
+
+	dbus_connection_send(conn, message, NULL);
+
+	dbus_message_unref(message);
+}
+
+void sni_context_menu(struct StatusNotifierItem *item, uint32_t x, uint32_t y) {
+	const char *iface =
+		(item->kde_special_snowflake ? "org.kde.StatusNotifierItem"
+		 : "org.freedesktop.StatusNotifierItem");
+	DBusMessage *message = dbus_message_new_method_call(
+			item->name,
+			"/StatusNotifierItem",
+			iface,
+			"ContextMenu");
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_INT32, &x,
+			DBUS_TYPE_INT32, &y,
+			DBUS_TYPE_INVALID);
+
+	dbus_connection_send(conn, message, NULL);
+
+	dbus_message_unref(message);
+}
+void sni_secondary(struct StatusNotifierItem *item, uint32_t x, uint32_t y) {
+	const char *iface =
+		(item->kde_special_snowflake ? "org.kde.StatusNotifierItem"
+		 : "org.freedesktop.StatusNotifierItem");
+	DBusMessage *message = dbus_message_new_method_call(
+			item->name,
+			"/StatusNotifierItem",
+			iface,
+			"SecondaryActivate");
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_INT32, &x,
+			DBUS_TYPE_INT32, &y,
+			DBUS_TYPE_INVALID);
+
+	dbus_connection_send(conn, message, NULL);
+
+	dbus_message_unref(message);
+}
+
+static void get_unique_name(struct StatusNotifierItem *item) {
+	// I think that we're fine being sync here becaues the message is
+	// directly to the message bus. Could be async though.
+	DBusMessage *message = dbus_message_new_method_call(
+			"org.freedesktop.DBus",
+			"/org/freedesktop/DBus",
+			"org.freedesktop.DBus",
+			"GetNameOwner");
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_STRING, &item->name,
+			DBUS_TYPE_INVALID);
+
+	DBusMessage *reply = dbus_connection_send_with_reply_and_block(
+			conn, message, -1, NULL);
+
+	dbus_message_unref(message);
+
+	if (!reply) {
+		sway_log(L_ERROR, "Could not get unique name for item: %s",
+				item->name);
+		return;
+	}
+
+	if (!dbus_message_get_args(reply, NULL,
+				DBUS_TYPE_STRING, &item->unique_name,
+				DBUS_TYPE_INVALID)) {
+		item->unique_name = NULL;
+		sway_log(L_ERROR, "Error parsing method args");
+	}
+
+	dbus_message_unref(reply);
+}
+
+struct StatusNotifierItem *sni_create(const char *name) {
+	struct StatusNotifierItem *item = malloc(sizeof(struct StatusNotifierItem));
+	item->name = strdup(name);
+	item->unique_name = NULL;
+	item->image = NULL;
+	item->dirty = false;
+
+	// If it doesn't use this name then assume that it uses the KDE spec
+	// This is because xembed-sni-proxy uses neither "org.freedesktop" nor
+	// "org.kde" and just gives us the items "unique name"
+	//
+	// We could use this to our advantage and fill out the "unique name"
+	// field with the given name if it is neither freedesktop or kde, but
+	// that's makes us rely on KDE hackyness which is bad practice
+	const char freedesktop_name[] = "org.freedesktop";
+	if (strncmp(name, freedesktop_name, sizeof(freedesktop_name) - 1) != 0) {
+		item->kde_special_snowflake = true;
+	} else {
+		item->kde_special_snowflake = false;
+	}
+
+	get_icon(item);
+
+	get_unique_name(item);
+
+	return item;
+}
+/* Return true if `item` has a name of `str` */
+int sni_str_cmp(const void *_item, const void *_str) {
+	const struct StatusNotifierItem *item = _item;
+	const char *str = _str;
+
+	return strcmp(item->name, str);
+}
+/* Returns true if `item` has a unique name of `str` */
+int sni_uniq_cmp(const void *_item, const void *_str) {
+	const struct StatusNotifierItem *item = _item;
+	const char *str = _str;
+
+	if (!item->unique_name) {
+		return false;
+	}
+	return strcmp(item->unique_name, str);
+}
+void sni_free(struct StatusNotifierItem *item) {
+	if (!item) {
+		return;
+	}
+	free(item->name);
+	if (item->image) {
+		cairo_surface_destroy(item->image);
+	}
+	free(item);
+}

swaybar/tray/sni_watcher.c

@@ -0,0 +1,487 @@
+#define _XOPEN_SOURCE 500
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <dbus/dbus.h>
+#include "swaybar/tray/dbus.h"
+#include "list.h"
+#include "log.h"
+
+static list_t *items = NULL;
+static list_t *hosts = NULL;
+
+/**
+ * Describes the function of the StatusNotifierWatcher
+ * See https://freedesktop.org/wiki/Specifications/StatusNotifierItem/StatusNotifierWatcher/
+ *
+ * We also implement KDE's special snowflake protocol, it's like this but with
+ * all occurrences 'freedesktop' replaced with 'kde'. There is no KDE introspect.
+ */
+static const char *interface_xml =
+	"<!DOCTYPE node PUBLIC '-//freedesktop//DTD D-BUS Object Introspection 1.0//EN'"
+	"'http://www.freedesktop.org/standards/dbus/1.0/introspect.dtd'>"
+	"<node>"
+	"  <interface name='org.freedesktop.DBus.Introspectable'>"
+	"    <method name='Introspect'>"
+	"       <arg name='xml_data' direction='out' type='s'/>"
+	"    </method>"
+	"  </interface>"
+	"  <interface name='org.freedesktop.DBus.Properties'>"
+	"    <method name='Get'>"
+	"       <arg name='interface' direction='in' type='s'/>"
+	"       <arg name='propname' direction='in' type='s'/>"
+	"       <arg name='value' direction='out' type='v'/>"
+	"    </method>"
+	"    <method name='Set'>"
+	"       <arg name='interface' direction='in' type='s'/>"
+	"       <arg name='propname' direction='in' type='s'/>"
+	"       <arg name='value' direction='in' type='v'/>"
+	"    </method>"
+	"    <method name='GetAll'>"
+	"       <arg name='interface' direction='in' type='s'/>"
+	"       <arg name='props' direction='out' type='a{sv}'/>"
+	"    </method>"
+	"  </interface>"
+	"  <interface name='org.freedesktop.StatusNotifierWatcher'>"
+	"    <method name='RegisterStatusNotifierItem'>"
+	"      <arg type='s' name='service' direction='in'/>"
+	"    </method>"
+	"    <method name='RegisterStatusNotifierHost'>"
+	"      <arg type='s' name='service' direction='in'/>"
+	"    </method>"
+	"    <property name='RegisteredStatusNotifierItems' type='as' access='read'/>"
+	"    <property name='IsStatusNotifierHostRegistered' type='b' access='read'/>"
+	"    <property name='ProtocolVersion' type='i' access='read'/>"
+	"    <signal name='StatusNotifierItemRegistered'>"
+	"      <arg type='s' name='service' direction='out'/>"
+	"    </signal>"
+	"    <signal name='StatusNotifierItemUnregistered'>"
+	"      <arg type='s' name='service' direction='out'/>"
+	"    </signal>"
+	"    <signal name='StatusNotifierHostRegistered'>"
+	"      <arg type='' name='service' direction='out'/>"
+	"    </signal>"
+	"  </interface>"
+	"</node>";
+
+static void host_registered_signal(DBusConnection *connection) {
+	// Send one signal for each protocol
+	DBusMessage *signal = dbus_message_new_signal(
+			"/StatusNotifierWatcher",
+			"org.freedesktop.StatusNotifierWatcher",
+			"StatusNotifierHostRegistered");
+
+	dbus_connection_send(connection, signal, NULL);
+	dbus_message_unref(signal);
+
+
+	signal = dbus_message_new_signal(
+			"/StatusNotifierWatcher",
+			"org.kde.StatusNotifierWatcher",
+			"StatusNotifierHostRegistered");
+
+	dbus_connection_send(connection, signal, NULL);
+	dbus_message_unref(signal);
+}
+static void item_registered_signal(DBusConnection *connection, const char *name) {
+	DBusMessage *signal = dbus_message_new_signal(
+			"/StatusNotifierWatcher",
+			"org.freedesktop.StatusNotifierWatcher",
+			"StatusNotifierItemRegistered");
+	dbus_message_append_args(signal,
+			DBUS_TYPE_STRING, &name,
+			DBUS_TYPE_INVALID);
+	dbus_connection_send(connection, signal, NULL);
+	dbus_message_unref(signal);
+
+	signal = dbus_message_new_signal(
+			"/StatusNotifierWatcher",
+			"org.kde.StatusNotifierWatcher",
+			"StatusNotifierItemRegistered");
+	dbus_message_append_args(signal,
+			DBUS_TYPE_STRING, &name,
+			DBUS_TYPE_INVALID);
+	dbus_connection_send(connection, signal, NULL);
+	dbus_message_unref(signal);
+}
+static void item_unregistered_signal(DBusConnection *connection, const char *name) {
+	DBusMessage *signal = dbus_message_new_signal(
+			"/StatusNotifierWatcher",
+			"org.freedesktop.StatusNotifierWatcher",
+			"StatusNotifierItemUnregistered");
+	dbus_message_append_args(signal,
+			DBUS_TYPE_STRING, &name,
+			DBUS_TYPE_INVALID);
+	dbus_connection_send(connection, signal, NULL);
+	dbus_message_unref(signal);
+
+	signal = dbus_message_new_signal(
+			"/StatusNotifierWatcher",
+			"org.kde.StatusNotifierWatcher",
+			"StatusNotifierItemUnregistered");
+	dbus_message_append_args(signal,
+			DBUS_TYPE_STRING, &name,
+			DBUS_TYPE_INVALID);
+	dbus_connection_send(connection, signal, NULL);
+	dbus_message_unref(signal);
+}
+
+static void respond_to_introspect(DBusConnection *connection, DBusMessage *request) {
+	DBusMessage *reply;
+
+	reply = dbus_message_new_method_return(request);
+	dbus_message_append_args(reply,
+			DBUS_TYPE_STRING, &interface_xml,
+			DBUS_TYPE_INVALID);
+	dbus_connection_send(connection, reply, NULL);
+	dbus_message_unref(reply);
+}
+
+static void register_item(DBusConnection *connection, DBusMessage *message) {
+	DBusError error;
+	char *name;
+
+	dbus_error_init(&error);
+	if (!dbus_message_get_args(message, &error,
+				DBUS_TYPE_STRING, &name,
+				DBUS_TYPE_INVALID)) {
+		sway_log(L_ERROR, "Error parsing method args: %s\n", error.message);
+	}
+
+	name = strdup(name);
+	sway_log(L_INFO, "RegisterStatusNotifierItem called with \"%s\"\n", name);
+
+	// Don't add duplicate or not real item
+	if (list_seq_find(items, (int (*)(const void *, const void *))strcmp, name) != -1) {
+		return;
+	}
+	if (!dbus_bus_name_has_owner(connection, name, &error)) {
+		return;
+	}
+
+	list_add(items, name);
+	item_registered_signal(connection, name);
+
+	// It's silly, but xembedsniproxy wants a reply for this function
+	DBusMessage *reply = dbus_message_new_method_return(message);
+	dbus_connection_send(connection, reply, NULL);
+	dbus_message_unref(reply);
+}
+
+static void register_host(DBusConnection *connection, DBusMessage *message) {
+	DBusError error;
+	char *name;
+
+	dbus_error_init(&error);
+	if (!dbus_message_get_args(message, &error,
+				DBUS_TYPE_STRING, &name,
+				DBUS_TYPE_INVALID)) {
+		sway_log(L_ERROR, "Error parsing method args: %s\n", error.message);
+	}
+
+	sway_log(L_INFO, "RegisterStatusNotifierHost called with \"%s\"\n", name);
+
+	// Don't add duplicate or not real host
+	if (list_seq_find(hosts, (int (*)(const void *, const void *))strcmp, name) != -1) {
+		return;
+	}
+	if (!dbus_bus_name_has_owner(connection, name, &error)) {
+		return;
+	}
+
+	list_add(hosts, strdup(name));
+	host_registered_signal(connection);
+}
+
+static void get_property(DBusConnection *connection, DBusMessage *message) {
+	DBusError error;
+	char *interface;
+	char *property;
+
+	dbus_error_init(&error);
+	if (!dbus_message_get_args(message, &error,
+				DBUS_TYPE_STRING, &interface,
+				DBUS_TYPE_STRING, &property,
+				DBUS_TYPE_INVALID)) {
+		sway_log(L_ERROR, "Error parsing prop args: %s\n", error.message);
+		return;
+	}
+
+	if (strcmp(property, "RegisteredStatusNotifierItems") == 0) {
+		sway_log(L_INFO, "Replying with items\n");
+		DBusMessage *reply;
+		reply = dbus_message_new_method_return(message);
+		DBusMessageIter iter;
+		DBusMessageIter sub;
+		DBusMessageIter subsub;
+
+		dbus_message_iter_init_append(reply, &iter);
+
+		dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT,
+				"as", &sub);
+		dbus_message_iter_open_container(&sub, DBUS_TYPE_ARRAY,
+				"s", &subsub);
+
+		for (int i = 0; i < items->length; ++i) {
+			dbus_message_iter_append_basic(&subsub,
+					DBUS_TYPE_STRING, &items->items[i]);
+		}
+
+		dbus_message_iter_close_container(&sub, &subsub);
+		dbus_message_iter_close_container(&iter, &sub);
+
+		dbus_connection_send(connection, reply, NULL);
+		dbus_message_unref(reply);
+	} else if (strcmp(property, "IsStatusNotifierHostRegistered") == 0) {
+		DBusMessage *reply;
+		DBusMessageIter iter;
+		DBusMessageIter sub;
+		int registered = (hosts == NULL || hosts->length == 0) ? 0 : 1;
+
+		reply = dbus_message_new_method_return(message);
+
+		dbus_message_iter_init_append(reply, &iter);
+
+		dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT,
+				"b", &sub);
+		dbus_message_iter_append_basic(&sub,
+				DBUS_TYPE_BOOLEAN, &registered);
+
+		dbus_message_iter_close_container(&iter, &sub);
+
+		dbus_connection_send(connection, reply, NULL);
+		dbus_message_unref(reply);
+	} else if (strcmp(property, "ProtocolVersion") == 0) {
+		DBusMessage *reply;
+		DBusMessageIter iter;
+		DBusMessageIter sub;
+		const int version = 0;
+
+		reply = dbus_message_new_method_return(message);
+
+		dbus_message_iter_init_append(reply, &iter);
+
+		dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT,
+				"i", &sub);
+		dbus_message_iter_append_basic(&sub,
+				DBUS_TYPE_INT32, &version);
+
+		dbus_message_iter_close_container(&iter, &sub);
+		dbus_connection_send(connection, reply, NULL);
+		dbus_message_unref(reply);
+	}
+}
+
+static void set_property(DBusConnection *connection, DBusMessage *message) {
+	// All properties are read only and we don't allow new properties
+	return;
+}
+
+static void get_all(DBusConnection *connection, DBusMessage *message) {
+	DBusMessage *reply;
+	reply = dbus_message_new_method_return(message);
+	DBusMessageIter iter; /* a{v} */
+	DBusMessageIter arr;
+	DBusMessageIter dict;
+	DBusMessageIter sub;
+	DBusMessageIter subsub;
+	int registered = (hosts == NULL || hosts->length == 0) ? 0 : 1;
+	const int version = 0;
+	const char *prop;
+
+	// Could clean this up with a function for each prop
+	dbus_message_iter_init_append(reply, &iter);
+	dbus_message_iter_open_container(&iter, DBUS_TYPE_ARRAY,
+			"{sv}", &arr);
+
+	prop = "RegisteredStatusNotifierItems";
+	dbus_message_iter_open_container(&arr, DBUS_TYPE_DICT_ENTRY,
+			NULL, &dict);
+	dbus_message_iter_append_basic(&dict,
+			DBUS_TYPE_STRING, &prop);
+	dbus_message_iter_open_container(&dict, DBUS_TYPE_VARIANT,
+			"as", &sub);
+	dbus_message_iter_open_container(&sub, DBUS_TYPE_ARRAY,
+			"s", &subsub);
+	for (int i = 0; i < items->length; ++i) {
+		dbus_message_iter_append_basic(&subsub,
+				DBUS_TYPE_STRING, &items->items[i]);
+	}
+	dbus_message_iter_close_container(&sub, &subsub);
+	dbus_message_iter_close_container(&dict, &sub);
+	dbus_message_iter_close_container(&arr, &dict);
+
+	prop = "IsStatusNotifierHostRegistered";
+	dbus_message_iter_open_container(&arr, DBUS_TYPE_DICT_ENTRY,
+			NULL, &dict);
+	dbus_message_iter_append_basic(&dict,
+			DBUS_TYPE_STRING, &prop);
+	dbus_message_iter_open_container(&dict, DBUS_TYPE_VARIANT,
+			"b", &sub);
+	dbus_message_iter_append_basic(&sub,
+			DBUS_TYPE_BOOLEAN, &registered);
+	dbus_message_iter_close_container(&dict, &sub);
+	dbus_message_iter_close_container(&arr, &dict);
+
+	prop = "ProtocolVersion";
+	dbus_message_iter_open_container(&arr, DBUS_TYPE_DICT_ENTRY,
+			NULL, &dict);
+	dbus_message_iter_append_basic(&dict,
+			DBUS_TYPE_STRING, &prop);
+	dbus_message_iter_open_container(&dict, DBUS_TYPE_VARIANT,
+			"i", &sub);
+	dbus_message_iter_append_basic(&sub,
+			DBUS_TYPE_INT32, &version);
+	dbus_message_iter_close_container(&dict, &sub);
+	dbus_message_iter_close_container(&arr, &dict);
+
+	dbus_message_iter_close_container(&iter, &arr);
+
+	dbus_connection_send(connection, reply, NULL);
+	dbus_message_unref(reply);
+}
+
+static DBusHandlerResult message_handler(DBusConnection *connection, 
+		DBusMessage *message, void *data) {
+	const char *interface_name = dbus_message_get_interface(message);
+	const char *member_name = dbus_message_get_member(message);
+
+	// In order of the xml above
+	if (strcmp(interface_name, "org.freedesktop.DBus.Introspectable") == 0 &&
+			strcmp(member_name, "Introspect") == 0) {
+		// We don't have an introspect for KDE
+		respond_to_introspect(connection, message);
+		return DBUS_HANDLER_RESULT_HANDLED;
+	} else if (strcmp(interface_name, "org.freedesktop.DBus.Properties") == 0) {
+		if (strcmp(member_name, "Get") == 0) {
+			get_property(connection, message);
+			return DBUS_HANDLER_RESULT_HANDLED;
+		} else if (strcmp(member_name, "Set") == 0) {
+			set_property(connection, message);
+			return DBUS_HANDLER_RESULT_HANDLED;
+		} else if (strcmp(member_name, "GetAll") == 0) {
+			get_all(connection, message);
+			return DBUS_HANDLER_RESULT_HANDLED;
+		} else {
+			return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+		}
+	} else if (strcmp(interface_name, "org.freedesktop.StatusNotifierWatcher") == 0 ||
+			strcmp(interface_name, "org.kde.StatusNotifierWatcher") == 0) {
+		if (strcmp(member_name, "RegisterStatusNotifierItem") == 0) {
+			register_item(connection, message);
+			return DBUS_HANDLER_RESULT_HANDLED;
+		} else if (strcmp(member_name, "RegisterStatusNotifierHost") == 0) {
+			register_host(connection, message);
+			return DBUS_HANDLER_RESULT_HANDLED;
+		} else {
+			return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+		}
+	}
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static DBusHandlerResult signal_handler(DBusConnection *connection,
+		DBusMessage *message, void *_data) {
+	if (dbus_message_is_signal(message, "org.freedesktop.DBus", "NameOwnerChanged")) {
+		// Only eat the message if it is name that we are watching
+		const char *name;
+		const char *old_owner;
+		const char *new_owner;
+		int index;
+		if (!dbus_message_get_args(message, NULL,
+				DBUS_TYPE_STRING, &name,
+				DBUS_TYPE_STRING, &old_owner,
+				DBUS_TYPE_STRING, &new_owner,
+				DBUS_TYPE_INVALID)) {
+			sway_log(L_ERROR, "Error getting LostName args");
+			return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+		}
+		if (strcmp(new_owner, "") != 0) {
+			// Name is not lost
+			return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+		}
+		if ((index = list_seq_find(items, (int (*)(const void *, const void *))strcmp, name)) != -1) {
+			sway_log(L_INFO, "Status Notifier Item lost %s", name);
+			free(items->items[index]);
+			list_del(items, index);
+			item_unregistered_signal(connection, name);
+
+			return DBUS_HANDLER_RESULT_HANDLED;
+		}
+		if ((index = list_seq_find(hosts, (int (*)(const void *, const void *))strcmp, name)) != -1) {
+			sway_log(L_INFO, "Status Notifier Host lost %s", name);
+			free(hosts->items[index]);
+			list_del(hosts, index);
+
+			return DBUS_HANDLER_RESULT_HANDLED;
+		}
+	}
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static const DBusObjectPathVTable vtable = {
+	.message_function = message_handler,
+	.unregister_function = NULL,
+};
+
+int init_sni_watcher() {
+	DBusError error;
+	dbus_error_init(&error);
+	if (!conn) {
+		sway_log(L_ERROR, "Connection is null, cannot initiate StatusNotifierWatcher");
+		return -1;
+	}
+
+	items = create_list();
+	hosts = create_list();
+
+	int status = dbus_bus_request_name(conn, "org.freedesktop.StatusNotifierWatcher",
+			DBUS_NAME_FLAG_REPLACE_EXISTING,
+			&error);
+	if (status == DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
+		sway_log(L_DEBUG, "Got watcher name");
+	} else if (status == DBUS_REQUEST_NAME_REPLY_IN_QUEUE) {
+		sway_log(L_INFO, "Could not get watcher name, it may start later");
+	}
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus err getting watcher name: %s\n", error.message);
+		return -1;
+	}
+
+	status = dbus_bus_request_name(conn, "org.kde.StatusNotifierWatcher",
+			DBUS_NAME_FLAG_REPLACE_EXISTING,
+			&error);
+	if (status == DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
+		sway_log(L_DEBUG, "Got kde watcher name");
+	} else if (status == DBUS_REQUEST_NAME_REPLY_IN_QUEUE) {
+		sway_log(L_INFO, "Could not get kde watcher name, it may start later");
+	}
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus err getting kde watcher name: %s\n", error.message);
+		return -1;
+	}
+
+	dbus_connection_try_register_object_path(conn,
+			"/StatusNotifierWatcher",
+			&vtable, NULL, &error);
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus_err: %s\n", error.message);
+		return -1;
+	}
+
+	dbus_bus_add_match(conn,
+			"type='signal',\
+			sender='org.freedesktop.DBus',\
+			interface='org.freedesktop.DBus',\
+			member='NameOwnerChanged'",
+			&error);
+
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "DBus error getting match args: %s", error.message);
+	}
+
+	dbus_connection_add_filter(conn, signal_handler, NULL, NULL);
+	return 0;
+}

swaybar/tray/tray.c

@@ -0,0 +1,279 @@
+#define _XOPEN_SOURCE 500
+#include <unistd.h>
+#include <stdlib.h>
+#include <string.h>
+#include <dbus/dbus.h>
+#include "swaybar/bar.h"
+#include "swaybar/tray/tray.h"
+#include "swaybar/tray/dbus.h"
+#include "swaybar/tray/sni.h"
+#include "swaybar/bar.h"
+#include "list.h"
+#include "log.h"
+
+struct tray *tray;
+
+static void register_host(char *name) {
+	DBusMessage *message;
+
+	message = dbus_message_new_method_call(
+			"org.freedesktop.StatusNotifierWatcher",
+			"/StatusNotifierWatcher",
+			"org.freedesktop.StatusNotifierWatcher",
+			"RegisterStatusNotifierHost");
+	if (!message) {
+		sway_log(L_ERROR, "Cannot allocate dbus method call");
+		return;
+	}
+
+	dbus_message_append_args(message,
+			DBUS_TYPE_STRING, &name,
+			DBUS_TYPE_INVALID);
+
+	dbus_connection_send(conn, message, NULL);
+
+	dbus_message_unref(message);
+}
+
+static void get_items_reply(DBusPendingCall *pending, void *_data) {
+	DBusMessage *reply = dbus_pending_call_steal_reply(pending);
+
+	if (!reply) {
+		sway_log(L_ERROR, "Got no items reply from sni watcher");
+		goto bail;
+	}
+
+	int message_type = dbus_message_get_type(reply);
+
+	if (message_type == DBUS_MESSAGE_TYPE_ERROR) {
+		char *msg;
+
+		dbus_message_get_args(reply, NULL,
+				DBUS_TYPE_STRING, &msg,
+				DBUS_TYPE_INVALID);
+
+		sway_log(L_ERROR, "Message is error: %s", msg);
+		goto bail;
+	}
+
+	DBusMessageIter iter;
+	DBusMessageIter variant;
+	DBusMessageIter array;
+
+	dbus_message_iter_init(reply, &iter);
+	if (dbus_message_iter_get_arg_type(&iter) != DBUS_TYPE_VARIANT) {
+		sway_log(L_ERROR, "Replyed with wrong type, not v(as)");
+		goto bail;
+	}
+	dbus_message_iter_recurse(&iter, &variant);
+	if (dbus_message_iter_get_arg_type(&variant) != DBUS_TYPE_ARRAY ||
+			dbus_message_iter_get_element_type(&variant) != DBUS_TYPE_STRING) {
+		sway_log(L_ERROR, "Replyed with wrong type, not v(as)");
+		goto bail;
+	}
+
+	// Clear list
+	list_foreach(tray->items, (void (*)(void *))sni_free);
+	list_free(tray->items);
+	tray->items = create_list();
+
+	// O(n) function, could be faster dynamically reading values
+	int len = dbus_message_iter_get_element_count(&variant);
+
+	dbus_message_iter_recurse(&variant, &array);
+	for (int i = 0; i < len; i++) {
+		const char *name;
+		dbus_message_iter_get_basic(&array, &name);
+
+		struct StatusNotifierItem *item = sni_create(name);
+
+		sway_log(L_DEBUG, "Item registered with host: %s", name);
+		list_add(tray->items, item);
+		dirty = true;
+	}
+
+bail:
+	dbus_message_unref(reply);
+	return;
+}
+static void get_items() {
+	DBusPendingCall *pending;
+	DBusMessage *message = dbus_message_new_method_call(
+			"org.freedesktop.StatusNotifierWatcher",
+			"/StatusNotifierWatcher",
+			"org.freedesktop.DBus.Properties",
+			"Get");
+
+	const char *iface = "org.freedesktop.StatusNotifierWatcher";
+	const char *prop = "RegisteredStatusNotifierItems";
+	dbus_message_append_args(message,
+			DBUS_TYPE_STRING, &iface,
+			DBUS_TYPE_STRING, &prop,
+			DBUS_TYPE_INVALID);
+
+	bool status =
+		dbus_connection_send_with_reply(conn, message, &pending, -1);
+	dbus_message_unref(message);
+
+	if (!(pending || status)) {
+		sway_log(L_ERROR, "Could not get items");
+		return;
+	}
+
+	dbus_pending_call_set_notify(pending, get_items_reply, NULL, NULL);
+}
+
+static DBusHandlerResult signal_handler(DBusConnection *connection,
+		DBusMessage *message, void *_data) {
+	if (dbus_message_is_signal(message, "org.freedesktop.StatusNotifierWatcher",
+				"StatusNotifierItemRegistered")) {
+		const char *name;
+		if (!dbus_message_get_args(message, NULL,
+				DBUS_TYPE_STRING, &name,
+				DBUS_TYPE_INVALID)) {
+			sway_log(L_ERROR, "Error getting StatusNotifierItemRegistered args");
+			return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+		}
+
+		if (list_seq_find(tray->items, sni_str_cmp, name) == -1) {
+			struct StatusNotifierItem *item = sni_create(name);
+
+			list_add(tray->items, item);
+			dirty = true;
+		}
+
+		return DBUS_HANDLER_RESULT_HANDLED;
+	} else if (dbus_message_is_signal(message, "org.freedesktop.StatusNotifierWatcher",
+				"StatusNotifierItemUnregistered")) {
+		const char *name;
+		if (!dbus_message_get_args(message, NULL,
+				DBUS_TYPE_STRING, &name,
+				DBUS_TYPE_INVALID)) {
+			sway_log(L_ERROR, "Error getting StatusNotifierItemUnregistered args");
+			return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+		}
+
+		int index;
+		if ((index = list_seq_find(tray->items, sni_str_cmp, name)) != -1) {
+			sni_free(tray->items->items[index]);
+			list_del(tray->items, index);
+			dirty = true;
+		} else {
+			// If it's not in our list, then our list is incorrect.
+			// Fetch all items again
+			sway_log(L_INFO, "Host item list incorrect, refreshing");
+			get_items();
+		}
+
+		return DBUS_HANDLER_RESULT_HANDLED;
+	} else if (dbus_message_is_signal(message, "org.freedesktop.StatusNotifierItem",
+				"NewIcon") || dbus_message_is_signal(message,
+				"org.kde.StatusNotifierItem", "NewIcon")) {
+		const char *name;
+		int index;
+		struct StatusNotifierItem *item;
+
+		name = dbus_message_get_sender(message);
+		if ((index = list_seq_find(tray->items, sni_uniq_cmp, name)) != -1) {
+			item = tray->items->items[index];
+			get_icon(item);
+		}
+
+		return DBUS_HANDLER_RESULT_HANDLED;
+	}
+	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+int init_tray() {
+	tray = (struct tray *)malloc(sizeof(tray));
+
+	tray->items = create_list();
+
+	DBusError error;
+	dbus_error_init(&error);
+	char *name = NULL;
+	if (!conn) {
+		sway_log(L_ERROR, "Connection is null, cannot init SNI host");
+		goto err;
+	}
+	name = calloc(sizeof(char), 256);
+
+	if (!name) {
+		sway_log(L_ERROR, "Cannot allocate name");
+		goto err;
+	}
+
+	pid_t pid = getpid();
+	if (snprintf(name, 256, "org.freedesktop.StatusNotifierHost-%d", pid)
+			>= 256) {
+		sway_log(L_ERROR, "Cannot get host name because string is too short."
+				"This should not happen");
+		goto err;
+	}
+
+	// We want to be the sole owner of this name
+	if (dbus_bus_request_name(conn, name, DBUS_NAME_FLAG_DO_NOT_QUEUE,
+			&error) != DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER) {
+		sway_log(L_ERROR, "Cannot get host name and start the tray");
+		goto err;
+	}
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "Dbus err getting host name: %s\n", error.message);
+		goto err;
+	}
+	sway_log(L_DEBUG, "Got host name");
+
+	register_host(name);
+
+	get_items();
+
+	// Perhaps use addmatch helper functions like wlc does?
+	dbus_bus_add_match(conn,
+			"type='signal',\
+			sender='org.freedesktop.StatusNotifierWatcher',\
+			member='StatusNotifierItemRegistered'",
+			&error);
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus_err: %s", error.message);
+		goto err;
+	}
+	dbus_bus_add_match(conn,
+			"type='signal',\
+			sender='org.freedesktop.StatusNotifierWatcher',\
+			member='StatusNotifierItemUnregistered'",
+			&error);
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus_err: %s", error.message);
+		return -1;
+	}
+
+	// SNI matches
+	dbus_bus_add_match(conn,
+			"type='signal',\
+			interface='org.freedesktop.StatusNotifierItem',\
+			member='NewIcon'",
+			&error);
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus_err %s", error.message);
+		goto err;
+	}
+	dbus_bus_add_match(conn,
+			"type='signal',\
+			interface='org.kde.StatusNotifierItem',\
+			member='NewIcon'",
+			&error);
+	if (dbus_error_is_set(&error)) {
+		sway_log(L_ERROR, "dbus_err %s", error.message);
+		goto err;
+	}
+
+	dbus_connection_add_filter(conn, signal_handler, NULL, NULL);
+
+	free(name);
+	return 0;
+
+err:
+	// TODO better handle errors
+	free(name);
+	return -1;
+}

wayland/cairo.c

@@ -8,6 +8,25 @@ void cairo_set_source_u32(cairo_t *cairo, uint32_t color) {
 			(color >> (0*8) & 0xFF) / 255.0);
 }
 
+cairo_surface_t *cairo_image_surface_scale(cairo_surface_t *image, int width, int height) {
+	int image_width = cairo_image_surface_get_width(image);
+	int image_height = cairo_image_surface_get_height(image);
+
+	cairo_surface_t *new =
+		cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height);
+
+	cairo_t *cairo = cairo_create(new);
+
+	cairo_scale(cairo, (double) width / image_width, (double) height / image_height);
+
+	cairo_set_source_surface(cairo, image, 0, 0);
+	cairo_paint(cairo);
+
+	cairo_destroy(cairo);
+
+	return new;
+}
+
 #ifdef WITH_GDK_PIXBUF
 #include <gdk-pixbuf/gdk-pixbuf.h>