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

10 files changed, 213 insertions, 18 deletions

diff --git a/sway/commands.c b/sway/commands.c
index 34218491..f83b5287 100644
--- a/sway/commands.c
+++ b/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 },
diff --git a/sway/commands/bar/activate_button.c b/sway/commands/bar/activate_button.c
new file mode 100644
index 00000000..32a1d3e5
--- /dev/null
+++ b/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
+}
diff --git a/sway/commands/bar/context_button.c b/sway/commands/bar/context_button.c
new file mode 100644
index 00000000..6d7d7aec
--- /dev/null
+++ b/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
+}
diff --git a/sway/commands/bar/icon_theme.c b/sway/commands/bar/icon_theme.c
new file mode 100644
index 00000000..cbfc0be5
--- /dev/null
+++ b/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
+}
diff --git a/sway/commands/bar/secondary_button.c b/sway/commands/bar/secondary_button.c
new file mode 100644
index 00000000..745045c5
--- /dev/null
+++ b/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
+}
diff --git a/sway/commands/bar/tray_output.c b/sway/commands/bar/tray_output.c
index 8a1b5d35..012304a9 100644
--- a/sway/commands/bar/tray_output.c
+++ b/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
 }
diff --git a/sway/commands/bar/tray_padding.c b/sway/commands/bar/tray_padding.c
index 8c559f65..ac0572ce 100644
--- a/sway/commands/bar/tray_padding.c
+++ b/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 (padding < 0) {
-		return cmd_results_new(CMD_INVALID, "tray_padding",
-				"Invalid padding value %s, minimum is 0", argv[0]);
+	if (argc == 1 || (argc == 2 && strcasecmp("px", argv[1]) == 0)) {
+		char *inv;
+		uint32_t padding = strtoul(argv[0], &inv, 10);
+		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);
+		}
 	}
-
-	if (argc > 1 && strcasecmp("px", argv[1]) != 0) {
-		return cmd_results_new(CMD_INVALID, "tray_padding",
-				"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);
+	return cmd_results_new(CMD_FAILURE, cmd_name,
+		"Expected 'tray_padding <padding>[px]'");
+#endif
 }
diff --git a/sway/config.c b/sway/config.c
index 85823953..e0b65615 100644
--- a/sway/config.c
+++ b/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
diff --git a/sway/ipc-json.c b/sway/ipc-json.c
index 512144a4..31de53f0 100644
--- a/sway/ipc-json.c
+++ b/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)));
diff --git a/sway/sway-bar.5.txt b/sway/sway-bar.5.txt
index 5a52e7db..29487662 100644
--- a/sway/sway-bar.5.txt
+++ b/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
 ------