name-rev: replace static buffer with strbuf

When name-rev needs to format an actual name, we do so into
a fixed-size buffer. That includes the actual ref tip, as
well as any traversal information. Since refs can exceed
1024 bytes, this means you can get a bogus result. E.g.,
doing:

   git tag $(perl -e 'print join("/", 1..1024)')
   git describe --contains HEAD^

results in ".../282/283", when it should be
".../1023/1024~1".

We can solve this by using a heap buffer. We'll use a
strbuf, which lets us write into the same buffer from our
loop without having to reallocate.

Signed-off-by: Jeff King <peff@peff.net>
This commit is contained in:
Jeff King 2017-03-28 15:46:44 -04:00 committed by Junio C Hamano
parent cddac45219
commit 903fc7da44

View file

@ -238,10 +238,9 @@ static const char *get_exact_ref_match(const struct object *o)
return NULL;
}
/* returns a static buffer */
static const char *get_rev_name(const struct object *o)
/* may return a constant string or use "buf" as scratch space */
static const char *get_rev_name(const struct object *o, struct strbuf *buf)
{
static char buffer[1024];
struct rev_name *n;
struct commit *c;
@ -258,10 +257,9 @@ static const char *get_rev_name(const struct object *o)
int len = strlen(n->tip_name);
if (len > 2 && !strcmp(n->tip_name + len - 2, "^0"))
len -= 2;
snprintf(buffer, sizeof(buffer), "%.*s~%d", len, n->tip_name,
n->generation);
return buffer;
strbuf_reset(buf);
strbuf_addf(buf, "%.*s~%d", len, n->tip_name, n->generation);
return buf->buf;
}
}
@ -271,10 +269,11 @@ static void show_name(const struct object *obj,
{
const char *name;
const struct object_id *oid = &obj->oid;
struct strbuf buf = STRBUF_INIT;
if (!name_only)
printf("%s ", caller_name ? caller_name : oid_to_hex(oid));
name = get_rev_name(obj);
name = get_rev_name(obj, &buf);
if (name)
printf("%s\n", name);
else if (allow_undefined)
@ -283,6 +282,7 @@ static void show_name(const struct object *obj,
printf("%s\n", find_unique_abbrev(oid->hash, DEFAULT_ABBREV));
else
die("cannot describe '%s'", oid_to_hex(oid));
strbuf_release(&buf);
}
static char const * const name_rev_usage[] = {
@ -294,6 +294,7 @@ static char const * const name_rev_usage[] = {
static void name_rev_line(char *p, struct name_ref_data *data)
{
struct strbuf buf = STRBUF_INIT;
int forty = 0;
char *p_start;
for (p_start = p; *p; p++) {
@ -314,7 +315,7 @@ static void name_rev_line(char *p, struct name_ref_data *data)
struct object *o =
lookup_object(sha1);
if (o)
name = get_rev_name(o);
name = get_rev_name(o, &buf);
}
*(p+1) = c;
@ -332,6 +333,8 @@ static void name_rev_line(char *p, struct name_ref_data *data)
/* flush */
if (p_start != p)
fwrite(p_start, p - p_start, 1, stdout);
strbuf_release(&buf);
}
int cmd_name_rev(int argc, const char **argv, const char *prefix)