Merge pull request #917 from dequis/wcwidth-wrapper

Add a wrapper of wcwidth() that picks the best implementation

src/core/Makefile.am

@@ -53,6 +53,7 @@ libcore_a_SOURCES = \
 	utf8.c \
 	$(regex_impl) \
 	wcwidth.c \
+	wcwidth-wrapper.c \
 	tls.c \
 	write-buffer.c
 

src/core/core.c

@@ -60,6 +60,9 @@ void chat_commands_deinit(void);
 void log_away_init(void);
 void log_away_deinit(void);
 
+void wcwidth_wrapper_init(void);
+void wcwidth_wrapper_deinit(void);
+
 int irssi_gui;
 int irssi_init_finished;
 int reload_config;
@@ -258,6 +261,7 @@ void core_init(void)
 	nicklist_init();
 
 	chat_commands_init();
+	wcwidth_wrapper_init();
 
 	settings_add_str("misc", "ignore_signals", "");
 	settings_add_bool("misc", "override_coredump_limit", FALSE);
@@ -281,6 +285,7 @@ void core_deinit(void)
 	signal_remove("setup changed", (SIGNAL_FUNC) read_settings);
 	signal_remove("irssi init finished", (SIGNAL_FUNC) sig_irssi_init_finished);
 
+	wcwidth_wrapper_deinit();
 	chat_commands_deinit();
 
 	nicklist_deinit();

src/core/utf8.c

@@ -36,7 +36,7 @@ int string_advance(char const **str, int policy)
 		c = g_utf8_get_char(*str);
 		*str = g_utf8_next_char(*str);
 
-		return unichar_isprint(c) ? mk_wcwidth(c) : 1;
+		return unichar_isprint(c) ? i_wcwidth(c) : 1;
 	} else {
 		/* Assume TREAT_STRING_AS_BYTES: */
 		*str += 1;

src/core/utf8.h

@@ -12,8 +12,14 @@
 typedef guint32 unichar;
 
 /* Returns width for character (0-2). */
+int i_wcwidth(unichar c);
+
+/* Older variant of the above */
 int mk_wcwidth(unichar c);
 
+/* Signature for wcwidth implementations */
+typedef int (*WCWIDTH_FUNC) (unichar ucs);
+
 /* Advance the str pointer one character further; return the number of columns
  * occupied by the skipped character.
  */

src/core/wcwidth-wrapper.c

@@ -0,0 +1,141 @@
+/*
+ wcwidth-wrapper.c : irssi
+
+    Copyright (C) 2018 dequis
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+*/
+
+#define _GNU_SOURCE
+#include <wchar.h>
+
+#include "module.h"
+#include "signals.h"
+#include "settings.h"
+#include "utf8.h"
+
+#ifdef HAVE_LIBUTF8PROC
+#include <utf8proc.h>
+#endif
+
+/* wcwidth=2 since unicode 5.2.0 */
+#define UNICODE_SQUARE_HIRAGANA_HOKA 0x1F200
+
+/* wcwidth=2 since unicode 9.0.0 */
+#define UNICODE_IRSSI_LOGO 0x1F525
+
+enum {
+	WCWIDTH_IMPL_OLD,
+	WCWIDTH_IMPL_SYSTEM
+#ifdef HAVE_LIBUTF8PROC
+	,WCWIDTH_IMPL_JULIA
+#endif
+};
+
+WCWIDTH_FUNC wcwidth_impl_func = mk_wcwidth;
+
+int i_wcwidth(unichar ucs)
+{
+	return (*wcwidth_impl_func)(ucs);
+}
+
+static int system_wcwidth(unichar ucs)
+{
+	int retval = wcwidth((wchar_t) ucs);
+
+	if (retval < 0) {
+		/* Treat all unknown characters as taking one cell. This is
+		 * the reason mk_wcwidth and other outdated implementations
+		 * mostly worked with newer unicode, while glibc's wcwidth
+		 * needs updating to recognize new characters.
+		 *
+		 * Instead of relying on that, we keep the behavior of assuming
+		 * one cell even for glibc's implementation, which is still
+		 * highly accurate and less of a headache overall.
+		 */
+		return 1;
+	}
+
+	return retval;
+}
+
+#ifdef HAVE_LIBUTF8PROC
+/* wrapper because the function signatures are different
+ * (the parameter is unsigned for us, signed for them) */
+static int julia_wcwidth(unichar ucs)
+{
+	return utf8proc_charwidth(ucs);
+}
+#endif
+
+static void read_settings(void)
+{
+	static int choice = -1;
+	int newchoice;
+
+	newchoice = settings_get_choice("wcwidth_implementation");
+
+	if (choice == newchoice) {
+		return;
+	}
+
+	choice = newchoice;
+
+	switch (choice) {
+	case WCWIDTH_IMPL_OLD:
+		wcwidth_impl_func = &mk_wcwidth;
+		break;
+
+	case WCWIDTH_IMPL_SYSTEM:
+		wcwidth_impl_func = &system_wcwidth;
+		break;
+
+#ifdef HAVE_LIBUTF8PROC
+	case WCWIDTH_IMPL_JULIA:
+		wcwidth_impl_func = &julia_wcwidth;
+		break;
+#endif
+	}
+
+}
+
+void wcwidth_wrapper_init(void)
+{
+	int wcwidth_impl_default = 0;
+	/* Test against characters that have wcwidth=2
+	 * since unicode 5.2 and 9.0 respectively */
+
+	if (system_wcwidth(UNICODE_SQUARE_HIRAGANA_HOKA) == 2 ||
+	    system_wcwidth(UNICODE_IRSSI_LOGO) == 2) {
+		wcwidth_impl_default = WCWIDTH_IMPL_SYSTEM;
+	} else {
+		/* Fall back to our own (which implements 5.0) */
+		wcwidth_impl_default = WCWIDTH_IMPL_OLD;
+	}
+
+#ifdef HAVE_LIBUTF8PROC
+	settings_add_choice("misc", "wcwidth_implementation", wcwidth_impl_default, "old;system;julia");
+#else
+	settings_add_choice("misc", "wcwidth_implementation", wcwidth_impl_default, "old;system");
+#endif
+
+	read_settings();
+	signal_add_first("setup changed", (SIGNAL_FUNC) read_settings);
+}
+
+void wcwidth_wrapper_deinit(void)
+{
+	signal_remove("setup changed", (SIGNAL_FUNC) read_settings);
+}