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

1 files changed, 463 insertions, 0 deletions

diff --git a/swaybar/tray/sni.c b/swaybar/tray/sni.c
new file mode 100644
index 00000000..f0638dca
--- /dev/null
+++ b/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);
+}