From 0d3fd8ae03eb180e1309f8b0bfd2fbce6c3cfdcc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Thu, 17 May 2018 10:55:21 +0200
Subject: basic/string-util: add a convenience function to cescape mostly-ascii
 fields
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

It's not supposed to be the most efficient, but instead fast and simple to use.

I kept the logic in ellipsize_mem() to use unicode ellipsis even in non-unicode
locales. I'm not quite convinced things should be this way, especially that with
this patch it'd actually be simpler to always use "…" in unicode locale and "..."
otherwise, but Lennart wanted it this way for some reason.
---
 src/basic/string-util.c | 70 ++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 54 insertions(+), 16 deletions(-)

(limited to 'src/basic/string-util.c')

diff --git a/src/basic/string-util.c b/src/basic/string-util.c
index 498e31122..f241a3376 100644
--- a/src/basic/string-util.c
+++ b/src/basic/string-util.c
@@ -14,6 +14,7 @@
 #include <string.h>
 
 #include "alloc-util.h"
+//#include "escape.h"
 #include "gunicode.h"
 //#include "locale-util.h"
 #include "macro.h"
@@ -457,6 +458,20 @@ bool string_has_cc(const char *p, const char *ok) {
         return false;
 }
 
+static int write_ellipsis(char *buf, bool unicode) {
+        if (unicode || is_locale_utf8()) {
+                buf[0] = 0xe2; /* tri-dot ellipsis: … */
+                buf[1] = 0x80;
+                buf[2] = 0xa6;
+        } else {
+                buf[0] = '.';
+                buf[1] = '.';
+                buf[2] = '.';
+        }
+
+        return 3;
+}
+
 static char *ascii_ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigned percent) {
         size_t x, need_space;
         char *r;
@@ -505,17 +520,7 @@ static char *ascii_ellipsize_mem(const char *s, size_t old_length, size_t new_le
         assert(x <= new_length - need_space);
 
         memcpy(r, s, x);
-
-        if (is_locale_utf8()) {
-                r[x+0] = 0xe2; /* tri-dot ellipsis: … */
-                r[x+1] = 0x80;
-                r[x+2] = 0xa6;
-        } else {
-                r[x+0] = '.';
-                r[x+1] = '.';
-                r[x+2] = '.';
-        }
-
+        write_ellipsis(r + x, false);
         memcpy(r + x + 3,
                s + old_length - (new_length - x - need_space),
                new_length - x - need_space + 1);
@@ -600,23 +605,56 @@ char *ellipsize_mem(const char *s, size_t old_length, size_t new_length, unsigne
         */
 
         memcpy(e, s, len);
-        e[len + 0] = 0xe2; /* tri-dot ellipsis: … */
-        e[len + 1] = 0x80;
-        e[len + 2] = 0xa6;
-
+        write_ellipsis(e + len, true);
         memcpy(e + len + 3, j, len2 + 1);
 
         return e;
 }
 
 char *ellipsize(const char *s, size_t length, unsigned percent) {
-
         if (length == (size_t) -1)
                 return strdup(s);
 
         return ellipsize_mem(s, strlen(s), length, percent);
 }
 
+char *cellescape(char *buf, size_t len, const char *s) {
+        /* Escape and ellipsize s into buffer buf of size len. Only non-control ASCII
+         * characters are copied as they are, everything else is escaped. The result
+         * is different then if escaping and ellipsization was performed in two
+         * separate steps, because each sequence is either stored in full or skipped.
+         *
+         * This function should be used for logging about strings which expected to
+         * be plain ASCII in a safe way.
+         *
+         * An ellipsis will be used if s is too long. It was always placed at the
+         * very end.
+         */
+
+        size_t i;
+        const char *t = s;
+
+        assert(len > 4 + 4 + 1); /* two chars and the terminator */
+
+        for (i = 0; i < len - 9; t++) {
+                if (!*t)
+                        goto done;
+                i += cescape_char(*t, buf + i);
+        }
+
+        /* We have space for one more char and terminating nul at this point */
+        if (*t) {
+                if (*(t+1))
+                        i += write_ellipsis(buf + i, false);
+                else
+                        i += cescape_char(*t, buf + i);
+        }
+
+ done:
+        buf[i] = '\0';
+        return buf;
+}
+
 bool nulstr_contains(const char *nulstr, const char *needle) {
         const char *i;
 
-- 
cgit v1.2.3