From 49342f1039b41d2c95dde3f9cc26efbdc85d0272 Mon Sep 17 00:00:00 2001
From: Ashish Kumar Yadav <ashishkumar.yadav@students.iiserpune.ac.in>
Date: Wed, 11 Aug 2021 20:24:07 +0530
Subject: [PATCH] Implement support for CSI 22 and 23

This patch implements title stack into st.
---
 st.c    | 34 +++++++++++++++++++++++++++++++---
 st.info |  4 ++--
 win.h   |  4 +++-
 x.c     | 44 +++++++++++++++++++++++++++++++++++++++-----
 4 files changed, 75 insertions(+), 11 deletions(-)

diff --git a/st.c b/st.c
index 76b7e0d..092b93c 100644
--- a/st.c
+++ b/st.c
@@ -1806,6 +1806,33 @@ csihandle(void)
 			goto unknown;
 		}
 		break;
+	case 't': /* title stack operations */
+		switch (csiescseq.arg[0]) {
+		case 22: /* pust current title on stack */
+			switch (csiescseq.arg[1]) {
+			case 0:
+			case 1:
+			case 2:
+				xpushtitle();
+				break;
+			default:
+				goto unknown;
+			}
+			break;
+		case 23: /* pop last title from stack */
+			switch (csiescseq.arg[1]) {
+			case 0:
+			case 1:
+			case 2:
+				xsettitle(NULL, 1);
+				break;
+			default:
+				goto unknown;
+			}
+			break;
+		default:
+			goto unknown;
+		}
 	}
 }
 
@@ -1856,7 +1883,7 @@ strhandle(void)
 		case 1:
 		case 2:
 			if (narg > 1)
-				xsettitle(strescseq.args[1]);
+				xsettitle(strescseq.args[1], 0);
 			return;
 		case 52:
 			if (narg > 2 && allowwindowops) {
@@ -1892,7 +1919,7 @@ strhandle(void)
 		}
 		break;
 	case 'k': /* old title set compatibility */
-		xsettitle(strescseq.args[0]);
+		xsettitle(strescseq.args[0], 0);
 		return;
 	case 'P': /* DCS -- Device Control String */
 	case '_': /* APC -- Application Program Command */
@@ -2264,6 +2291,7 @@ eschandle(uchar ascii)
 		break;
 	case 'c': /* RIS -- Reset to initial state */
 		treset();
+		xfreetitlestack();
 		resettitle();
 		xloadcols();
 		break;
@@ -2546,7 +2574,7 @@ tresize(int col, int row)
 void
 resettitle(void)
 {
-	xsettitle(NULL);
+	xsettitle(NULL, 0);
 }
 
 void
diff --git a/st.info b/st.info
index 8201ad6..aeef606 100644
--- a/st.info
+++ b/st.info
@@ -161,7 +161,7 @@ st-mono| simpleterm monocolor,
 	rin=\E[%p1%dT,
 	ritm=\E[23m,
 	rmacs=\E(B,
-	rmcup=\E[?1049l,
+	rmcup=\E[?1049l\E[23;0;0t,
 	rmir=\E[4l,
 	rmkx=\E[?1l\E>,
 	rmso=\E[27m,
@@ -172,7 +172,7 @@ st-mono| simpleterm monocolor,
 	sitm=\E[3m,
 	sgr0=\E[0m,
 	smacs=\E(0,
-	smcup=\E[?1049h,
+	smcup=\E[?1049h\E[22;0;0t,
 	smir=\E[4h,
 	smkx=\E[?1h\E=,
 	smso=\E[7m,
diff --git a/win.h b/win.h
index a6ef1b9..e24337e 100644
--- a/win.h
+++ b/win.h
@@ -30,7 +30,9 @@ void xdrawline(Line, int, int, int);
 void xfinishdraw(void);
 void xloadcols(void);
 int xsetcolorname(int, const char *);
-void xsettitle(char *);
+void xfreetitlestack(void);
+void xsettitle(char *, int);
+void xpushtitle(void);
 int xsetcursor(int);
 void xsetmode(int, unsigned int);
 void xsetpointermotion(int);
diff --git a/x.c b/x.c
index 210f184..b4bebff 100644
--- a/x.c
+++ b/x.c
@@ -63,6 +63,9 @@ static void ttysend(const Arg *);
 /* config.h for applying patches and the configuration. */
 #include "config.h"
 
+/* size of title stack */
+#define TITLESTACKSIZE 8
+
 /* XEMBED messages */
 #define XEMBED_FOCUS_IN  4
 #define XEMBED_FOCUS_OUT 5
@@ -220,6 +223,8 @@ static DC dc;
 static XWindow xw;
 static XSelection xsel;
 static TermWindow win;
+static int tstki; /* title stack index */
+static char *titlestack[TITLESTACKSIZE]; /* title stack */
 
 /* Font Ring Cache */
 enum {
@@ -1580,18 +1585,47 @@ xsetenv(void)
 }
 
 void
-xsettitle(char *p)
+xfreetitlestack(void)
 {
-	XTextProperty prop;
-	DEFAULT(p, opt_title);
+	for (int i = 0; i < LEN(titlestack); i++) {
+		free(titlestack[i]);
+		titlestack[i] = NULL;
+	}
+}
 
-	Xutf8TextListToTextProperty(xw.dpy, &p, 1, XUTF8StringStyle,
-			&prop);
+void
+xsettitle(char *p, int pop)
+{
+ 	XTextProperty prop;
+ 
+	free(titlestack[tstki]);
+	if (pop) {
+		titlestack[tstki] = NULL;
+		tstki = (tstki - 1 + TITLESTACKSIZE) % TITLESTACKSIZE;
+		p = titlestack[tstki] ? titlestack[tstki] : opt_title;
+	} else if (p) {
+		titlestack[tstki] = xstrdup(p);
+	} else {
+		titlestack[tstki] = NULL;
+		p = opt_title;
+	}
+ 
+ 	Xutf8TextListToTextProperty(xw.dpy, &p, 1, XUTF8StringStyle, &prop);
 	XSetWMName(xw.dpy, xw.win, &prop);
 	XSetTextProperty(xw.dpy, xw.win, &prop, xw.netwmname);
 	XFree(prop.value);
 }
 
+void
+xpushtitle(void)
+{
+	int tstkin = (tstki + 1) % TITLESTACKSIZE;
+
+	free(titlestack[tstkin]);
+	titlestack[tstkin] = titlestack[tstki] ? xstrdup(titlestack[tstki]) : NULL;
+	tstki = tstkin;
+}
+
 int
 xstartdraw(void)
 {
-- 
2.32.0