From 8d91e51f7b554aa85be6e3b5cd7dde6a02a3c2d0 Mon Sep 17 00:00:00 2001
From: dogeystamp <dogeystamp@disroot.org>
Date: Tue, 2 Jan 2024 12:27:48 -0500
Subject: [PATCH] [st] patch: externalpipe

---
 suckless/st/config.def.h |  5 +++
 suckless/st/st.c         | 78 +++++++++++++++++++++++++++++++++++++++-
 suckless/st/st.h         |  1 +
 3 files changed, 83 insertions(+), 1 deletion(-)

diff --git a/suckless/st/config.def.h b/suckless/st/config.def.h
index e14775c..64c6a99 100644
--- a/suckless/st/config.def.h
+++ b/suckless/st/config.def.h
@@ -183,6 +183,10 @@ static MouseShortcut mshortcuts[] = {
 	{ XK_ANY_MOD,           Button5, ttysend,        {.s = "\005"} },
 };
 
+static char *screeneditcmd[] = { "/bin/sh", "-c",
+	"screen-edit.sh",
+	"externalpipe", NULL };
+
 /* Internal keyboard shortcuts. */
 #define MODKEY Mod1Mask
 #define TERMMOD (ControlMask|ShiftMask)
@@ -204,6 +208,7 @@ static Shortcut shortcuts[] = {
 	{ ShiftMask,            XK_Page_Up,     kscrollup,      {.i = -1} },
 	{ ShiftMask,            XK_Page_Down,   kscrolldown,    {.i = -1} },
 	{ TERMMOD,              XK_Return,      newterm,        {.i =  0} },
+	{ TERMMOD,              XK_U,           externalpipe,   { .v = screeneditcmd } },
 };
 
 /*
diff --git a/suckless/st/st.c b/suckless/st/st.c
index cd8d8f9..1ecca39 100644
--- a/suckless/st/st.c
+++ b/suckless/st/st.c
@@ -46,6 +46,7 @@
 #define TLINE(y)		((y) < term.scr ? term.hist[((y) + term.histi - \
 				term.scr + HISTSIZE + 1) % HISTSIZE] : \
 				term.line[(y) - term.scr])
+#define TLINE_HIST(y)           ((y) <= HISTSIZE-term.row+2 ? term.hist[(y)] : term.line[(y-HISTSIZE+term.row-3)])
 
 enum term_mode {
 	MODE_WRAP        = 1 << 0,
@@ -426,6 +427,20 @@ tlinelen(int y)
 	return i;
 }
 
+int
+tlinehistlen(int y)
+{
+	int i = term.col;
+
+	if (TLINE_HIST(y)[i - 1].mode & ATTR_WRAP)
+		return i;
+
+	while (i > 0 && TLINE_HIST(y)[i - 1].u == ' ')
+		--i;
+
+	return i;
+}
+
 void
 selstart(int col, int row, int snap)
 {
@@ -726,8 +741,14 @@ sigchld(int a)
 	if ((p = waitpid(pid, &stat, WNOHANG)) < 0)
 		die("waiting for pid %hd failed: %s\n", pid, strerror(errno));
 
-	if (pid != p)
+	if (pid != p) {
+		if (p == 0 && wait(&stat) < 0)
+			die("wait: %s\n", strerror(errno));
+
+		/* reinstall sigchld handler */
+		signal(SIGCHLD, sigchld);
 		return;
+	}
 
 	if (WIFEXITED(stat) && WEXITSTATUS(stat))
 		die("child exited with status %d\n", WEXITSTATUS(stat));
@@ -2084,6 +2105,61 @@ strparse(void)
 	}
 }
 
+void
+externalpipe(const Arg *arg)
+{
+	int to[2];
+	char buf[UTF_SIZ];
+	void (*oldsigpipe)(int);
+	Glyph *bp, *end;
+	int lastpos, n, newline;
+
+	if (pipe(to) == -1)
+		return;
+
+	switch (fork()) {
+	case -1:
+		close(to[0]);
+		close(to[1]);
+		return;
+	case 0:
+		dup2(to[0], STDIN_FILENO);
+		close(to[0]);
+		close(to[1]);
+		execvp(((char **)arg->v)[0], (char **)arg->v);
+		fprintf(stderr, "st: execvp %s\n", ((char **)arg->v)[0]);
+		perror("failed");
+		exit(0);
+	}
+
+	close(to[0]);
+	/* ignore sigpipe for now, in case child exists early */
+	oldsigpipe = signal(SIGPIPE, SIG_IGN);
+	newline = 0;
+	for (n = 0; n <= HISTSIZE + 2; n++) {
+		bp = TLINE_HIST(n);
+		lastpos = MIN(tlinehistlen(n) + 1, term.col) - 1;
+		if (lastpos < 0)
+			break;
+        if (lastpos == 0)
+            continue;
+		end = &bp[lastpos + 1];
+		for (; bp < end; ++bp)
+			if (xwrite(to[1], buf, utf8encode(bp->u, buf)) < 0)
+				break;
+		if ((newline = TLINE_HIST(n)[lastpos].mode & ATTR_WRAP))
+			continue;
+		if (xwrite(to[1], "\n", 1) < 0)
+			break;
+		newline = 0;
+	}
+	if (newline)
+		(void)xwrite(to[1], "\n", 1);
+	close(to[1]);
+	/* restore */
+	signal(SIGPIPE, oldsigpipe);
+}
+
 void
 strdump(void)
 {
diff --git a/suckless/st/st.h b/suckless/st/st.h
index f638558..0757c29 100644
--- a/suckless/st/st.h
+++ b/suckless/st/st.h
@@ -85,6 +85,7 @@ void draw(void);
 void kscrolldown(const Arg *);
 void kscrollup(const Arg *);
 void newterm(const Arg *);
+void externalpipe(const Arg *);
 void printscreen(const Arg *);
 void printsel(const Arg *);
 void sendbreak(const Arg *);