From e7f523c898983c84ba3102675662dc33cbb5573e Mon Sep 17 00:00:00 2001
From: Nihal Jere <noocsharp@gmail.com>
Date: Sat, 21 Mar 2020 15:50:00 -0500
Subject: [PATCH] fsignal

---
 config.def.h |  7 +++++++
 dwm.c        | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/config.def.h b/config.def.h
index 1c0b587..8d2e6e9 100644
--- a/config.def.h
+++ b/config.def.h
@@ -113,3 +113,10 @@ static Button buttons[] = {
 	{ ClkTagBar,            MODKEY,         Button3,        toggletag,      {0} },
 };
 
+/* signal definitions */
+/* signum must be greater than 0 */
+/* trigger signals using `xsetroot -name "fsignal:<signum>"` */
+static Signal signals[] = {
+	/* signum       function        argument  */
+	{ 1,            setlayout,      {.v = 0} },
+};
diff --git a/dwm.c b/dwm.c
index 4465af1..db2ee08 100644
--- a/dwm.c
+++ b/dwm.c
@@ -106,6 +106,12 @@ typedef struct {
 	const Arg arg;
 } Key;
 
+typedef struct {
+	unsigned int signum;
+	void (*func)(const Arg *);
+	const Arg arg;
+} Signal;
+
 typedef struct {
 	const char *symbol;
 	void (*arrange)(Monitor *);
@@ -176,6 +182,7 @@ static void grabbuttons(Client *c, int focused);
 static void grabkeys(void);
 static void incnmaster(const Arg *arg);
 static void keypress(XEvent *e);
+static int fake_signal(void);
 static void killclient(const Arg *arg);
 static void manage(Window w, XWindowAttributes *wa);
 static void mappingnotify(XEvent *e);
@@ -998,6 +1005,47 @@ keypress(XEvent *e)
 			keys[i].func(&(keys[i].arg));
 }
 
+int
+fake_signal(void)
+{
+	char fsignal[256];
+	char indicator[9] = "fsignal:";
+	char str_signum[16];
+	int i, v, signum;
+	size_t len_fsignal, len_indicator = strlen(indicator);
+
+	// Get root name property
+	if (gettextprop(root, XA_WM_NAME, fsignal, sizeof(fsignal))) {
+		len_fsignal = strlen(fsignal);
+
+		// Check if this is indeed a fake signal
+		if (len_indicator > len_fsignal ? 0 : strncmp(indicator, fsignal, len_indicator) == 0) {
+			memcpy(str_signum, &fsignal[len_indicator], len_fsignal - len_indicator);
+			str_signum[len_fsignal - len_indicator] = '\0';
+
+			// Convert string value into managable integer
+			for (i = signum = 0; i < strlen(str_signum); i++) {
+				v = str_signum[i] - '0';
+				if (v >= 0 && v <= 9) {
+					signum = signum * 10 + v;
+				}
+			}
+
+			// Check if a signal was found, and if so handle it
+			if (signum)
+				for (i = 0; i < LENGTH(signals); i++)
+					if (signum == signals[i].signum && signals[i].func)
+						signals[i].func(&(signals[i].arg));
+
+			// A fake signal was sent
+			return 1;
+		}
+	}
+
+	// No fake signal was sent, so proceed with update
+	return 0;
+}
+
 void
 killclient(const Arg *arg)
 {
@@ -1215,8 +1263,10 @@ propertynotify(XEvent *e)
 	Window trans;
 	XPropertyEvent *ev = &e->xproperty;
 
-	if ((ev->window == root) && (ev->atom == XA_WM_NAME))
-		updatestatus();
+	if ((ev->window == root) && (ev->atom == XA_WM_NAME)) {
+		if (!fake_signal())
+			updatestatus();
+    }
 	else if (ev->state == PropertyDelete)
 		return; /* ignore */
 	else if ((c = wintoclient(ev->window))) {
-- 
2.25.1