MINOR: cfgparse: add cfg_find_best_match() to suggest an existing word

Instead of just reporting "unknown keyword", let's provide a function which
will look through a list of registered keywords for a similar-looking word
to the one that wasn't matched. This will help callers suggest correct
spelling. Also, given that a large part of the config parser still relies
on a long chain of strcmp(), we'll need to be able to pass extra candidates.
Thus the function supports an optional extra list for this purpose.
This commit is contained in:
Willy Tarreau 2021-03-12 09:08:04 +01:00
parent ba2c4459a5
commit e2afcc4509
2 changed files with 47 additions and 0 deletions

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@ -113,6 +113,7 @@ int alertif_too_many_args(int maxarg, const char *file, int linenum, char **args
int parse_process_number(const char *arg, unsigned long *proc, int max, int *autoinc, char **err);
unsigned long parse_cpu_set(const char **args, unsigned long *cpu_set, char **err);
void free_email_alert(struct proxy *p);
const char *cfg_find_best_match(const char *word, const struct list *list, int section, const char **extra);
/*
* Sends a warning if proxy <proxy> does not have at least one of the

View File

@ -332,6 +332,52 @@ int warnif_cond_conflicts(const struct acl_cond *cond, unsigned int where, const
return ERR_WARN;
}
/* try to find in <list> the word that looks closest to <word> by counting
* transitions between letters, digits and other characters. Will return the
* best matching word if found, otherwise NULL. An optional array of extra
* words to compare may be passed in <extra>, but it must then be terminated
* by a NULL entry. If unused it may be NULL.
*/
const char *cfg_find_best_match(const char *word, const struct list *list, int section, const char **extra)
{
uint8_t word_sig[1024]; // 0..25=letter, 26=digit, 27=other, 28=begin, 29=end
uint8_t list_sig[1024];
const struct cfg_kw_list *kwl;
int index;
const char *best_ptr = NULL;
int dist, best_dist = INT_MAX;
make_word_fingerprint(word_sig, word);
list_for_each_entry(kwl, list, list) {
for (index = 0; kwl->kw[index].kw != NULL; index++) {
if (kwl->kw[index].section != section)
continue;
make_word_fingerprint(list_sig, kwl->kw[index].kw);
dist = word_fingerprint_distance(word_sig, list_sig);
if (dist < best_dist) {
best_dist = dist;
best_ptr = kwl->kw[index].kw;
}
}
}
while (extra && *extra) {
make_word_fingerprint(list_sig, *extra);
dist = word_fingerprint_distance(word_sig, list_sig);
if (dist < best_dist) {
best_dist = dist;
best_ptr = *extra;
}
extra++;
}
if (best_dist > 2 * strlen(word) || (best_ptr && best_dist > 2 * strlen(best_ptr)))
best_ptr = NULL;
return best_ptr;
}
/* Parse a string representing a process number or a set of processes. It must
* be "all", "odd", "even", a number between 1 and <max> or a range with
* two such numbers delimited by a dash ('-'). On success, it returns