From: Michael Ferrari <nekkodroid404@gmail.com>
Date: Sat, 14 Sep 2024 00:01:52 +0000 (+0200)
Subject: firstboot: add similar input suggestion
X-Git-Tag: v257-rc1~388
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=1e1ac5d53b0f126b6c4419506c7c42b67c07537f;p=thirdparty%2Fsystemd.git

firstboot: add similar input suggestion

This uses the same logic as similar verb suggestion for command line
utilities. Try to be helpful when the user entered something invalid
instead of just showing the prompt again.
---

diff --git a/src/basic/strv.c b/src/basic/strv.c
index 6c71f990c83..5b71c36dbfe 100644
--- a/src/basic/strv.c
+++ b/src/basic/strv.c
@@ -66,6 +66,33 @@ char* strv_find_startswith(char * const *l, const char *name) {
         return NULL;
 }
 
+char* strv_find_closest_by_levenshtein(char * const *l, const char *name) {
+        ssize_t best_distance = SSIZE_MAX;
+        char *best = NULL;
+
+        assert(name);
+
+        STRV_FOREACH(i, l) {
+                ssize_t distance;
+
+                distance = strlevenshtein(*i, name);
+                if (distance < 0) {
+                        log_debug_errno(distance, "Failed to determine Levenshtein distance between %s and %s: %m", *i, name);
+                        return NULL;
+                }
+
+                if (distance > 5) /* If the distance is just too far off, don't make a bad suggestion */
+                        continue;
+
+                if (distance < best_distance) {
+                        best_distance = distance;
+                        best = *i;
+                }
+        }
+
+        return best;
+}
+
 char* strv_find_first_field(char * const *needles, char * const *haystack) {
         STRV_FOREACH(k, needles) {
                 char *value = strv_env_pairs_get((char **)haystack, *k);
diff --git a/src/basic/strv.h b/src/basic/strv.h
index d38d5bf5384..b7845eeeccb 100644
--- a/src/basic/strv.h
+++ b/src/basic/strv.h
@@ -17,6 +17,7 @@ char* strv_find(char * const *l, const char *name) _pure_;
 char* strv_find_case(char * const *l, const char *name) _pure_;
 char* strv_find_prefix(char * const *l, const char *name) _pure_;
 char* strv_find_startswith(char * const *l, const char *name) _pure_;
+char* strv_find_closest_by_levenshtein(char * const *l, const char *name) _pure_;
 /* Given two vectors, the first a list of keys and the second a list of key-value pairs, returns the value
  * of the first key from the first vector that is found in the second vector. */
 char* strv_find_first_field(char * const *needles, char * const *haystack) _pure_;
diff --git a/src/firstboot/firstboot.c b/src/firstboot/firstboot.c
index f4601c02101..3899835d4c6 100644
--- a/src/firstboot/firstboot.c
+++ b/src/firstboot/firstboot.c
@@ -187,6 +187,7 @@ static int prompt_loop(const char *text, char **l, unsigned percentage, bool (*i
 
         for (;;) {
                 _cleanup_free_ char *p = NULL;
+                char *best_match = NULL;
                 unsigned u;
 
                 r = ask_string(&p, "%s %s (empty to skip, \"list\" to list options): ",
@@ -219,12 +220,20 @@ static int prompt_loop(const char *text, char **l, unsigned percentage, bool (*i
                         return free_and_strdup_warn(ret, l[u-1]);
                 }
 
-                if (!is_valid(p)) {
-                        log_error("Entered data invalid.");
-                        continue;
-                }
+                if (is_valid(p))
+                        return free_and_replace(*ret, p);
+
+                /* Be helperful to the user, and give a hint what the user might have wanted to
+                 * type. We search with two mechanisms: a simple prefix match and – if that didn't
+                 * yield results –, a Levenshtein word distance based match. */
+                best_match = strv_find_prefix(l, p);
+                if (!best_match)
+                        best_match = strv_find_closest_by_levenshtein(l, p);
 
-                return free_and_replace(*ret, p);
+                if (best_match)
+                        log_error("Invalid data '%s', did you mean '%s'?", p, best_match);
+                else
+                        log_error("Invalid data '%s'.", p);
         }
 }