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authorJeff King <peff@peff.net>2009-04-07 07:14:20 (GMT)
committerJunio C Hamano <gitster@pobox.com>2009-04-08 06:22:15 (GMT)
commit7c2b3029df45a74d0ebd11afcc94259791cfb90d (patch)
tree5c3888be7cb3dc41dbd6ef7d93a8b58f059a98ad /refs.c
parent8cae19d987b1bbd43258558f591e39d9d216dcb3 (diff)
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make get_short_ref a public function
Often we want to shorten a full ref name to something "prettier" to show a user. For example, "refs/heads/master" is often shown simply as "master", or "refs/remotes/origin/master" is shown as "origin/master". Many places in the code use a very simple formula: skip common prefixes like refs/heads, refs/remotes, etc. This is codified in the prettify_ref function. for-each-ref has a more correct (but more expensive) approach: consider the ref lookup rules, and try shortening as much as possible while remaining unambiguous. This patch makes the latter strategy globally available as shorten_unambiguous_ref. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'refs.c')
-rw-r--r--refs.c99
1 files changed, 99 insertions, 0 deletions
diff --git a/refs.c b/refs.c
index 59c373f..1e5e7b4 100644
--- a/refs.c
+++ b/refs.c
@@ -1652,3 +1652,102 @@ struct ref *find_ref_by_name(const struct ref *list, const char *name)
return (struct ref *)list;
return NULL;
}
+
+/*
+ * generate a format suitable for scanf from a ref_rev_parse_rules
+ * rule, that is replace the "%.*s" spec with a "%s" spec
+ */
+static void gen_scanf_fmt(char *scanf_fmt, const char *rule)
+{
+ char *spec;
+
+ spec = strstr(rule, "%.*s");
+ if (!spec || strstr(spec + 4, "%.*s"))
+ die("invalid rule in ref_rev_parse_rules: %s", rule);
+
+ /* copy all until spec */
+ strncpy(scanf_fmt, rule, spec - rule);
+ scanf_fmt[spec - rule] = '\0';
+ /* copy new spec */
+ strcat(scanf_fmt, "%s");
+ /* copy remaining rule */
+ strcat(scanf_fmt, spec + 4);
+
+ return;
+}
+
+char *shorten_unambiguous_ref(const char *ref)
+{
+ int i;
+ static char **scanf_fmts;
+ static int nr_rules;
+ char *short_name;
+
+ /* pre generate scanf formats from ref_rev_parse_rules[] */
+ if (!nr_rules) {
+ size_t total_len = 0;
+
+ /* the rule list is NULL terminated, count them first */
+ for (; ref_rev_parse_rules[nr_rules]; nr_rules++)
+ /* no +1 because strlen("%s") < strlen("%.*s") */
+ total_len += strlen(ref_rev_parse_rules[nr_rules]);
+
+ scanf_fmts = xmalloc(nr_rules * sizeof(char *) + total_len);
+
+ total_len = 0;
+ for (i = 0; i < nr_rules; i++) {
+ scanf_fmts[i] = (char *)&scanf_fmts[nr_rules]
+ + total_len;
+ gen_scanf_fmt(scanf_fmts[i], ref_rev_parse_rules[i]);
+ total_len += strlen(ref_rev_parse_rules[i]);
+ }
+ }
+
+ /* bail out if there are no rules */
+ if (!nr_rules)
+ return xstrdup(ref);
+
+ /* buffer for scanf result, at most ref must fit */
+ short_name = xstrdup(ref);
+
+ /* skip first rule, it will always match */
+ for (i = nr_rules - 1; i > 0 ; --i) {
+ int j;
+ int short_name_len;
+
+ if (1 != sscanf(ref, scanf_fmts[i], short_name))
+ continue;
+
+ short_name_len = strlen(short_name);
+
+ /*
+ * check if the short name resolves to a valid ref,
+ * but use only rules prior to the matched one
+ */
+ for (j = 0; j < i; j++) {
+ const char *rule = ref_rev_parse_rules[j];
+ unsigned char short_objectname[20];
+ char refname[PATH_MAX];
+
+ /*
+ * the short name is ambiguous, if it resolves
+ * (with this previous rule) to a valid ref
+ * read_ref() returns 0 on success
+ */
+ mksnpath(refname, sizeof(refname),
+ rule, short_name_len, short_name);
+ if (!read_ref(refname, short_objectname))
+ break;
+ }
+
+ /*
+ * short name is non-ambiguous if all previous rules
+ * haven't resolved to a valid ref
+ */
+ if (j == i)
+ return short_name;
+ }
+
+ free(short_name);
+ return xstrdup(ref);
+}