Add "machine" to the IPC and layout saving/restoring

docs/ipc

@@ -349,7 +349,8 @@ window (integer)::
 	X11-related tools display (usually in hex).
 window_properties (map)::
 	This optional field contains all available X11 window properties from the
-	following list: *title*, *instance*, *class*, *window_role* and *transient_for*.
+	following list: *title*, *instance*, *class*, *window_role*, *machine*
+	and *transient_for*.
 window_type (string)::
 	The window type (_NET_WM_WINDOW_TYPE). Possible values are undefined, normal,
 	dialog, utility, toolbar, splash, menu, dropdown_menu, popup_menu, tooltip and

docs/layout-saving

@@ -185,9 +185,9 @@ Therefore, if you just start Emacs via dmenu, it will not get swallowed by that
 container. Only if you start Emacs with the proper instance name (+emacs24
 --name notmuch+), it will get swallowed.
 
-You can match on "class", "instance", "window_role" and "title". All values are
-case-sensitive regular expressions (PCRE). Use +xprop(1)+ and click into a
-window to see its properties:
+You can match on "class", "instance", "window_role", "title" and "machine". All
+values are case-sensitive regular expressions (PCRE). Use +xprop(1)+ and click
+into a window to see its properties:
 
 --------------------------------------------------------------------------------
 $ xprop

src/ipc.c

@@ -572,6 +572,7 @@ void dump_node(yajl_gen gen, struct Con *con, bool inplace_restart) {
         DUMP_PROPERTY("class", class_class);
         DUMP_PROPERTY("instance", class_instance);
         DUMP_PROPERTY("window_role", role);
+        DUMP_PROPERTY("machine", machine);
 
         if (con->window->name != NULL) {
             ystr("title");
@@ -661,6 +662,7 @@ void dump_node(yajl_gen gen, struct Con *con, bool inplace_restart) {
         DUMP_REGEX(instance);
         DUMP_REGEX(window_role);
         DUMP_REGEX(title);
+        DUMP_REGEX(machine);
 
 #undef DUMP_REGEX
         y(map_close);

src/load_layout.c

@@ -275,6 +275,9 @@ static int json_string(void *ctx, const unsigned char *val, size_t len) {
         } else if (strcasecmp(last_key, "title") == 0) {
             current_swallow->title = regex_new(sval);
             swallow_is_empty = false;
+        } else if (strcasecmp(last_key, "machine") == 0) {
+            current_swallow->machine = regex_new(sval);
+            swallow_is_empty = false;
         } else {
             ELOG("swallow key %s unknown\n", last_key);
         }

src/restore_layout.c

@@ -154,6 +154,7 @@ static void update_placeholder_contents(placeholder_state *state) {
         APPEND_REGEX(instance);
         APPEND_REGEX(window_role);
         APPEND_REGEX(title);
+        APPEND_REGEX(machine);
 
         if (serialized == NULL) {
             DLOG("This swallows specification is not serializable?!\n");