Tidy up the terminal detection and feature code and add named sets of

terminal features, each of which are defined in one place and map to a
builtin set of terminfo(5) capabilities. Features can be specified based
on TERM with a new terminal-features option or with the -T flag when
running tmux. tmux will also detect a few common terminals from the DA
and DSR responses.

This is intended to make it easier to configure tmux's use of
terminfo(5) even in the presence of outdated ncurses(3) or terminfo(5)
databases or for features which do not yet have a terminfo(5) entry.
Instead of having to grok terminfo(5) capability names and what they
should be set to in the terminal-overrides option, the user can
hopefully just give tmux a feature name and let it do the right thing.

The terminal-overrides option remains both for backwards compatibility
and to allow tweaks of individual capabilities.

tmux already did much of this already, this makes it tidier and simpler
to configure.

1 files changed, 264 insertions, 0 deletions

diff --git a/tty-features.c b/tty-features.c
new file mode 100644
index 00000000..58cbae7b
--- /dev/null
+++ b/tty-features.c
@@ -0,0 +1,264 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2020 Nicholas Marriott <nicholas.marriott@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "tmux.h"
+
+/*
+ * Still hardcoded:
+ * - bracket paste (sent if application asks for it);
+ * - mouse (under kmous capability);
+ * - focus events (under focus-events option);
+ * - default colours (under AX or op capabilities);
+ * - AIX colours (under colors >= 16);
+ * - alternate escape (under XT).
+ *
+ * Also:
+ * - XT is used to decide whether to send DA and DSR,
+ * - DECSLRM and DECFRA use a flag instead of capabilities.
+ * - Sync is a flag rather than a string capability.
+ * - UTF-8 is a separate flag on the client; needed for unattached clients.
+ */
+
+/* A named terminal feature. */
+struct tty_feature {
+	const char	 *name;
+	const char	**capabilities;
+	int		  flags;
+};
+
+/* Terminal has xterm(1) title setting. */
+static const char *tty_feature_title_capabilities[] = {
+	"tsl=\\E]0;", /* should be using TS really */
+	"fsl=\\a",
+	NULL
+};
+static struct tty_feature tty_feature_title = {
+	"title",
+	tty_feature_title_capabilities,
+	0
+};
+
+/* Terminal can set the clipboard with OSC 52. */
+static const char *tty_feature_clipboard_capabilities[] = {
+	"Ms=\\E]52;%p1%s;%p2%s\\a",
+	NULL
+};
+static struct tty_feature tty_feature_clipboard = {
+	"clipboard",
+	tty_feature_clipboard_capabilities,
+	0
+};
+
+/*
+ * Terminal supports RGB colour. This replaces setab and setaf also since
+ * terminals with RGB have versions that do not allow setting colours from the
+ * 256 palette.
+ */
+static const char *tty_feature_rgb_capabilities[] = {
+	"setrgbf=\\E[38;2;%p1%d;%p2%d;%p3%dm",
+	"setrgbb=\\E[48;2;%p1%d;%p2%d;%p3%dm",
+	"setab=\\E[%?%p1%{8}%<%t4%p1%d%e%p1%{16}%<%t10%p1%{8}%-%d%e48;5;%p1%d%;m",
+	"setaf=\\E[%?%p1%{8}%<%t3%p1%d%e%p1%{16}%<%t9%p1%{8}%-%d%e38;5;%p1%d%;m",
+	NULL
+};
+static struct tty_feature tty_feature_rgb = {
+	"RGB",
+	tty_feature_rgb_capabilities,
+	(TERM_256COLOURS|TERM_RGBCOLOURS)
+};
+
+/* Terminal supports 256 colours. */
+static const char *tty_feature_256_capabilities[] = {
+	"setab=\\E[%?%p1%{8}%<%t4%p1%d%e%p1%{16}%<%t10%p1%{8}%-%d%e48;5;%p1%d%;m",
+	"setaf=\\E[%?%p1%{8}%<%t3%p1%d%e%p1%{16}%<%t9%p1%{8}%-%d%e38;5;%p1%d%;m",
+	NULL
+};
+static struct tty_feature tty_feature_256 = {
+	"256",
+	tty_feature_256_capabilities,
+	TERM_256COLOURS
+};
+
+/* Terminal supports overline. */
+static const char *tty_feature_overline_capabilities[] = {
+	"Smol=\\E[53m",
+	NULL
+};
+static struct tty_feature tty_feature_overline = {
+	"overline",
+	tty_feature_overline_capabilities,
+	0
+};
+
+/* Terminal supports underscore styles. */
+static const char *tty_feature_usstyle_capabilities[] = {
+	"Smulx=\E[4::%p1%dm",
+	"Setulc=\E[58::2::%p1%{65536}%/%d::%p1%{256}%/%{255}%&%d::%p1%{255}%&%d%;m",
+	NULL
+};
+static struct tty_feature tty_feature_usstyle = {
+	"usstyle",
+	tty_feature_usstyle_capabilities,
+	0
+};
+
+/* Terminal supports cursor styles. */
+static const char *tty_feature_cstyle_capabilities[] = {
+	"Ss=\\E[%p1%d q",
+	"Se=\\E[2 q",
+	NULL
+};
+static struct tty_feature tty_feature_cstyle = {
+	"cstyle",
+	tty_feature_cstyle_capabilities,
+	0
+};
+
+/* Terminal supports cursor colours. */
+static const char *tty_feature_ccolour_capabilities[] = {
+	"Cs=\\E]12;%p1%s\\a",
+	"Cr=\\E]112\\a",
+	NULL
+};
+static struct tty_feature tty_feature_ccolour = {
+	"ccolour",
+	tty_feature_ccolour_capabilities,
+	0
+};
+
+/* Terminal supports synchronized updates. */
+static const char *tty_feature_sync_capabilities[] = {
+	"Sync",
+	NULL
+};
+static struct tty_feature tty_feature_sync = {
+	"sync",
+	tty_feature_sync_capabilities,
+	0
+};
+
+/* Terminal supports DECSLRM margins. */
+static struct tty_feature tty_feature_margins = {
+	"margins",
+	NULL,
+	TERM_DECSLRM
+};
+
+/* Terminal supports DECFRA rectangle fill. */
+static struct tty_feature tty_feature_rectfill = {
+	"rectfill",
+	NULL,
+	TERM_DECFRA
+};
+
+/* Available terminal features. */
+static const struct tty_feature *tty_features[] = {
+	&tty_feature_256,
+	&tty_feature_clipboard,
+	&tty_feature_ccolour,
+	&tty_feature_cstyle,
+	&tty_feature_margins,
+	&tty_feature_overline,
+	&tty_feature_rectfill,
+	&tty_feature_rgb,
+	&tty_feature_sync,
+	&tty_feature_title,
+	&tty_feature_usstyle
+};
+
+void
+tty_add_features(int *feat, const char *s, const char *separators)
+{
+	const struct tty_feature	 *tf;
+	char				 *next, *loop, *copy;
+	u_int				  i;
+
+	loop = copy = xstrdup(s);
+	while ((next = strsep(&loop, separators)) != NULL) {
+		for (i = 0; i < nitems(tty_features); i++) {
+			tf = tty_features[i];
+			if (strcasecmp(tf->name, next) == 0)
+				break;
+		}
+		if (i == nitems(tty_features)) {
+			log_debug("unknown terminal feature: %s", next);
+			break;
+		}
+		if (~(*feat) & (1 << i)) {
+			log_debug("adding terminal feature: %s", tf->name);
+			(*feat) |= (1 << i);
+		}
+	}
+	free(copy);
+}
+
+const char *
+tty_get_features(int feat)
+{
+	const struct tty_feature	*tf;
+	static char			 s[512];
+	u_int				 i;
+
+	*s = '\0';
+	for (i = 0; i < nitems(tty_features); i++) {
+		if (~feat & (1 << i))
+			continue;
+		tf = tty_features[i];
+
+		strlcat(s, tf->name, sizeof s);
+		strlcat(s, ",", sizeof s);
+	}
+	if (*s != '\0')
+		s[strlen(s) - 1] = '\0';
+	return (s);
+}
+
+void
+tty_apply_features(struct tty_term *term, int feat)
+{
+	const struct tty_feature	 *tf;
+	const char			**capability;
+	u_int				  i;
+
+	if (feat == 0)
+		return;
+	log_debug("applying terminal features: %s", tty_get_features(feat));
+
+	for (i = 0; i < nitems(tty_features); i++) {
+		if ((term->features & (1 << i)) || (~feat & (1 << i)))
+			continue;
+		tf = tty_features[i];
+
+		log_debug("applying terminal feature: %s", tf->name);
+		if (tf->capabilities != NULL) {
+			capability = tf->capabilities;
+			while (*capability != NULL) {
+				log_debug("adding capability: %s", *capability);
+				tty_term_apply(term, *capability, 1);
+				capability++;
+			}
+		}
+		term->flags |= tf->flags;
+	}
+	term->features |= feat;
+}