for-each-ref: `:short` format for `refname`

[thirdparty/git.git] / builtin-for-each-ref.c

diff --git a/builtin-for-each-ref.c b/builtin-for-each-ref.c
index 21e92bbcb577c0361df51bd81e6fb5ab546619ea..9b44092671118e34b3b9c38a91f8330d8b3d95a5 100644 (file)
--- a/builtin-for-each-ref.c
+++ b/builtin-for-each-ref.c
@@ -545,6 +545,107 @@ static void grab_values(struct atom_value *val, int deref, struct object *obj, v
        }
 }
 
+/*
+ * 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;
+}
+
+/*
+ * Shorten the refname to an non-ambiguous form
+ */
+static char *get_short_ref(struct refinfo *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 ref->refname;
+
+       /* buffer for scanf result, at most ref->refname must fit */
+       short_name = xstrdup(ref->refname);
+
+       /* 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->refname, 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];
+
+                       /*
+                        * the short name is ambiguous, if it resolves
+                        * (with this previous rule) to a valid ref
+                        * read_ref() returns 0 on success
+                        */
+                       if (!read_ref(mkpath(rule, short_name_len, short_name),
+                                     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 ref->refname;
+}
+
+
 /*
  * Parse the object referred by ref, and grab needed value.
  */
@@ -570,13 +671,33 @@ static void populate_value(struct refinfo *ref)
        for (i = 0; i < used_atom_cnt; i++) {
                const char *name = used_atom[i];
                struct atom_value *v = &ref->value[i];
-               if (!strcmp(name, "refname"))
-                       v->s = ref->refname;
-               else if (!strcmp(name, "*refname")) {
-                       int len = strlen(ref->refname);
-                       char *s = xmalloc(len + 4);
-                       sprintf(s, "%s^{}", ref->refname);
-                       v->s = s;
+               int deref = 0;
+               if (*name == '*') {
+                       deref = 1;
+                       name++;
+               }
+               if (!prefixcmp(name, "refname")) {
+                       const char *formatp = strchr(name, ':');
+                       const char *refname = ref->refname;
+
+                       /* look for "short" refname format */
+                       if (formatp) {
+                               formatp++;
+                               if (!strcmp(formatp, "short"))
+                                       refname = get_short_ref(ref);
+                               else
+                                       die("unknown refname format %s",
+                                           formatp);
+                       }
+
+                       if (!deref)
+                               v->s = refname;
+                       else {
+                               int len = strlen(refname);
+                               char *s = xmalloc(len + 4);
+                               sprintf(s, "%s^{}", refname);
+                               v->s = s;
+                       }
                }
        }