From bfcfb26b00cb93a359469cb8817861439818b430 Mon Sep 17 00:00:00 2001
From: Guido Cella <guido@guidocella.xyz>
Date: Mon, 30 Sep 2024 08:40:25 +0200
Subject: [PATCH] allow switching to the configured tag when a window opens

Add a rule option to switch to the configured tag when a window opens,
then switch back when it closes.
---
 config.def.h |  6 +++---
 dwl.c        | 23 +++++++++++++++++++----
 2 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/config.def.h b/config.def.h
index 8a6eda0..59e3ac5 100644
--- a/config.def.h
+++ b/config.def.h
@@ -21,9 +21,9 @@ static const float fullscreen_bg[]         = {0.0f, 0.0f, 0.0f, 1.0f}; /* You ca
 static int log_level = WLR_ERROR;
 
 static const Rule rules[] = {
-	/* app_id             title       tags mask     isfloating   monitor */
-	{ "Gimp_EXAMPLE",     NULL,       0,            1,           -1 }, /* Start on currently visible tags floating, not tiled */
-	{ "firefox_EXAMPLE",  NULL,       1 << 8,       0,           -1 }, /* Start on ONLY tag "9" */
+	/* app_id             title       tags mask     switchtotag   isfloating   monitor */
+	{ "Gimp_EXAMPLE",     NULL,       0,            0             1,           -1 }, /* Start on currently visible tags floating, not tiled */
+	{ "firefox_EXAMPLE",  NULL,       1 << 8,       1             0,           -1 }, /* Start on ONLY tag "9" */
     /* default/example rule: can be changed but cannot be eliminated; at least one rule must exist */
 };
 
diff --git a/dwl.c b/dwl.c
index 44f3ad9..7a97d94 100644
--- a/dwl.c
+++ b/dwl.c
@@ -138,6 +138,7 @@ typedef struct {
 	unsigned int bw;
 	uint32_t tags;
 	int isfloating, isurgent, isfullscreen;
+	int switchtotag;
 	uint32_t resize; /* configure serial of a pending resize */
 } Client;
 
@@ -226,6 +227,7 @@ typedef struct {
 	const char *id;
 	const char *title;
 	uint32_t tags;
+	bool switchtotag;
 	int isfloating;
 	int monitor;
 } Rule;
@@ -241,7 +243,7 @@ typedef struct {
 
 /* function declarations */
 static void applybounds(Client *c, struct wlr_box *bbox);
-static void applyrules(Client *c);
+static void applyrules(Client *c, bool map);
 static void arrange(Monitor *m);
 static void arrangelayer(Monitor *m, struct wl_list *list,
 		struct wlr_box *usable_area, int exclusive);
@@ -474,7 +476,7 @@ applybounds(Client *c, struct wlr_box *bbox)
 }
 
 void
-applyrules(Client *c)
+applyrules(Client *c, bool map)
 {
 	/* rule matching */
 	const char *appid, *title;
@@ -496,6 +498,11 @@ applyrules(Client *c)
 				if (r->monitor == i++)
 					mon = m;
 			}
+			if (r->switchtotag && map) {
+				c->switchtotag = selmon->tagset[selmon->seltags];
+				mon->seltags ^= 1;
+				mon->tagset[selmon->seltags] = r->tags & TAGMASK;
+			}
 		}
 	}
 
@@ -864,7 +871,7 @@ commitnotify(struct wl_listener *listener, void *data)
 		 * a different monitor based on its title, this will likely select
 		 * a wrong monitor.
 		 */
-		applyrules(c);
+		applyrules(c, false);
 		if (c->mon) {
 			client_set_scale(client_surface(c), c->mon->wlr_output->scale);
 		}
@@ -1790,7 +1797,7 @@ mapnotify(struct wl_listener *listener, void *data)
 		c->isfloating = 1;
 		setmon(c, p->mon, p->tags);
 	} else {
-		applyrules(c);
+		applyrules(c, true);
 	}
 	printstatus();
 
@@ -2831,6 +2838,14 @@ unmapnotify(struct wl_listener *listener, void *data)
 		wl_list_remove(&c->flink);
 	}
 
+	if (c->switchtotag) {
+		Arg a = { .ui = c->switchtotag };
+		// Call view() -> arrange() -> checkidleinhibitor() before
+		// wlr_scene_node_destroy() to prevent a rare use after free of
+		// tree->node.
+		view(&a);
+	}
+
 	wlr_scene_node_destroy(&c->scene->node);
 	printstatus();
 	motionnotify(0, NULL, 0, 0, 0, 0);
-- 
2.52.0