Add link=/nolink to styles to specific a hyperlink. GitHub issue 4280

from Moritz Angermann.

format-draw.c

@@ -710,6 +710,7 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 					     "AFTER" };
 	size_t			 size = strlen(expanded);
 	struct screen		*os = octx->s, s[TOTAL];
+	struct hyperlinks	*hl = os->hyperlinks;
 	struct screen_write_ctx	 ctx[TOTAL];
 	u_int			 ocx = os->cx, ocy = os->cy, n, i, width[TOTAL];
 	u_int			 map[] = { LEFT,
@@ -723,7 +724,7 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 	struct grid_cell	 gc, current_default, base_default;
 	struct style		 sy, saved_sy;
 	struct utf8_data	*ud = &sy.gc.data;
-	const char		*cp, *end;
+	const char		*cp, *end, *link_uri;
 	enum utf8_state		 more;
 	char			*tmp;
 	struct format_range	*fr = NULL, *fr1;
@@ -838,6 +839,17 @@ format_draw(struct screen_write_ctx *octx, const struct grid_cell *base,
 			sy.gc.fg = base->fg;
 		}
 
+		/*
+		 * Resolve any hyperlink and store it in the cell. The URI
+		 * doubles as the internal ID so repeated links share one entry
+		 * and the ID stays stable across redraws.
+		 */
+		link_uri = style_link(&sy);
+		if (link_uri != NULL && hl != NULL)
+			sy.gc.link = hyperlinks_put(hl, link_uri, link_uri);
+		else
+			sy.gc.link = 0;
+
 		/* If this style has a fill colour, store it for later. */
 		if (sy.fill != 8)
 			fill = sy.fill;

style.c

@@ -42,9 +42,17 @@ static struct style style_default = {
 
 	STYLE_WIDTH_DEFAULT, 0, STYLE_PAD_DEFAULT,
 
-	STYLE_DEFAULT_BASE
+	STYLE_DEFAULT_BASE,
+
+	0
 };
 
+/*
+ * Global hyperlink set holding the URIs for #[link=...] styles, so a style
+ * only needs to store a small ID rather than the URI itself.
+ */
+static struct hyperlinks	*style_hyperlinks;
+
 /* Set range string. */
 static void
 style_set_range_string(struct style *sy, const char *s)
@@ -91,6 +99,7 @@ style_parse(struct style *sy, const struct grid_cell *base, const char *in)
 			sy->gc.us = base->us;
 			sy->gc.attr = base->attr;
 			sy->gc.flags = base->flags;
+			sy->link = 0;
 		} else if (strcasecmp(tmp, "ignore") == 0)
 			sy->ignore = 1;
 		else if (strcasecmp(tmp, "noignore") == 0)
@@ -234,7 +243,9 @@ style_parse(struct style *sy, const struct grid_cell *base, const char *in)
 		} else if (strcasecmp(tmp, "none") == 0)
 			sy->gc.attr = 0;
 		else if (end > 2 && strncasecmp(tmp, "no", 2) == 0) {
-			if (strcmp(tmp + 2, "attr") == 0)
+			if (strcmp(tmp + 2, "link") == 0)
+				sy->link = 0;
+			else if (strcmp(tmp + 2, "attr") == 0)
 				sy->gc.attr |= GRID_ATTR_NOATTR;
 			else {
 				value = attributes_fromstring(tmp + 2);
@@ -262,6 +273,15 @@ style_parse(struct style *sy, const struct grid_cell *base, const char *in)
 			if (errstr != NULL)
 				goto error;
 			sy->pad = (int)n;
+		} else if (strncasecmp(tmp, "link=", 5) == 0) {
+			if (tmp[5] == '\0')
+				sy->link = 0;
+			else {
+				if (style_hyperlinks == NULL)
+					style_hyperlinks = hyperlinks_init();
+				sy->link = hyperlinks_put(style_hyperlinks,
+				    tmp + 5, tmp + 5);
+			}
 		} else {
 			if ((value = attributes_fromstring(tmp)) == -1)
 				goto error;
@@ -284,8 +304,8 @@ style_tostring(struct style *sy)
 {
 	struct grid_cell	*gc = &sy->gc;
 	int			 off = 0;
-	const char		*comma = "", *tmp = "";
+	const char		*comma = "", *tmp = "", *uri;
-	static char		 s[1024];
+	static char		 s[2048];
 	char			 b[21];
 
 	*s = '\0';
@@ -389,15 +409,33 @@ style_tostring(struct style *sy)
 		comma = ",";
 	}
 	if (sy->pad >= 0) {
-		xsnprintf(s + off, sizeof s - off, "%spad=%u", comma,
+		off += xsnprintf(s + off, sizeof s - off, "%spad=%u", comma,
 		    sy->pad);
 		comma = ",";
 	}
+	uri = style_link(sy);
+	if (uri != NULL) {
+		xsnprintf(s + off, sizeof s - off, "%slink=%s", comma, uri);
+		comma = ",";
+	}
 	if (*s == '\0')
 		return ("default");
 	return (s);
 }
 
+/* Get the hyperlink URI for a style, or NULL if it has none. */
+const char *
+style_link(struct style *sy)
+{
+	const char	*uri;
+
+	if (sy->link == 0 || style_hyperlinks == NULL)
+		return (NULL);
+	if (!hyperlinks_get(style_hyperlinks, sy->link, &uri, NULL, NULL))
+		return (NULL);
+	return (uri);
+}
+
 /* Apply a style on top of the given style. */
 struct style *
 style_add(struct grid_cell *gc, struct options *oo, const char *name,

tmux.1

@@ -7266,6 +7266,28 @@ Set the width of the styled area.
 .Ar N
 may be a column count or a percentage (for example
 .Ql 50% ) .
+.It Xo Ic link=uri
+(or
+.Ic nolink )
+.Xc
+Make the styled text an OSC 8 hyperlink to
+.Ar uri ,
+for example
+.Ql #[link=https://example.com]text#[nolink] .
+This is emitted only to terminals with the
+.Ic hyperlinks
+feature (see
+.Ic terminal-features ) ;
+it works in the status line and in other formats drawn with styles.
+The link continues until
+.Ic nolink ,
+.Ic default ,
+or an empty
+.Ic link=
+is given.
+The
+.Ar uri
+may not contain spaces or commas and is limited in length.
 .It Xo Ic list=on ,
 .Ic list=focus ,
 .Ic list=left\-marker ,

tmux.h

@@ -984,6 +984,8 @@ struct style {
 	int			pad;
 
 	enum style_default_type	default_type;
+
+	u_int			link;
 };
 
 /* Cursor style. */
@@ -3960,6 +3962,7 @@ int		 style_parse(struct style *,const struct grid_cell *,
 int		 style_parse_colour(struct style *,
 		     const struct grid_cell *, const char *);
 const char	*style_tostring(struct style *);
+const char	*style_link(struct style *);
 struct style	*style_add(struct grid_cell *, struct options *,
 		     const char *, struct format_tree *);
 void		 style_apply(struct grid_cell *, struct options *,

tty-features.c

@@ -570,6 +570,7 @@ tty_default_features(int *feat, const char *name, u_int version)
 			      "cstyle,"
 			      "extkeys,"
 			      "focus,"
+		  	      "hyperlinks,"
 			      "usstyle"
 		},
 		{ .name = "XTerm",