On Tue, Nov 13, 2018 at 07:49:15PM -0500, Jeff King wrote:
> Yes, the packet_read_line_buf() interface will both advance the buf
> pointer and decrement the length. So if we want to "peek", we have to
> do so with a copy (there's a peek function if you use the packet_reader
> interface, but that might be overkill here).
>
> You can rewrite it like this, which is a pretty faithful conversion and
> passes the tests (but see below).
> [...]
Here's a version which is less faithful, but I think does sensible
things in all cases, and is much easier to follow. I get a little
nervous just because it tightens some cases, and one never knows if
other implementations might be relying on the looseness. E.g.:
- in the current code we'd still drop back to dumb http if the server
tells us "application/x-git-upload-pack" but the initial pktline
doesn't start with "#" (even though if it _does_ have "#" at
position 5 but isn't a valid pktline, we'd complain!)
- right now the v2 protocol does not require the server to say
"application/x-git-upload-pack" for the content-type
This patch tightens both of those (I also made a few stylistic tweaks,
and added the ERR condition to show where it would go). I dunno. Part of
me sees this as a nice cleanup, but maybe it is better to just leave it
alone. A lot of these behaviors are just how it happens to work now, and
not part of the spec, but we don't know what might be relying on them.
diff --git a/remote-curl.c b/remote-curl.c
index 762a55a75f..1adb96311b 100644
--- a/remote-curl.c
+++ b/remote-curl.c
@@ -330,9 +330,61 @@ static int get_protocol_http_header(enum protocol_version
version,
return 0;
}
+static void check_smart_http(struct discovery *d, const char *service,
+ struct strbuf *type)
+{
+ char *src_buf;
+ size_t src_len;
+ char *line;
+ const char *p;
+
+ if (!skip_prefix(type->buf, "application/x-", &p) ||
+ !skip_prefix(p, service, &p) ||
+ strcmp(p, "-advertisement"))
+ return;
+
+ /*
+ * We speculatively try to read a packet, which means we must preserve
+ * the original buf/len pair in some cases.
+ */
+ src_buf = d->buf;
+ src_len = d->len;
+ line = packet_read_line_buf(&src_buf, &src_len, NULL);
+ if (!line)
+ die("invalid server response; expected service, got flush
packet");
+
+ if (skip_prefix(line, "# service=", &p) && !strcmp(p, service)) {
+ /*
+ * The header can include additional metadata lines, up
+ * until a packet flush marker. Ignore these now, but
+ * in the future we might start to scan them.
+ */
+ while (packet_read_line_buf(&src_buf, &src_len, NULL))
+ ;
+
+ /*
+ * v0 smart http; callers expect us to soak up the
+ * service and header packets
+ */
+ d->buf = src_buf;
+ d->len = src_len;
+ d->proto_git = 1;
+
+ } else if (starts_with(line, "version 2")) { /* should be strcmp()? */
+ /*
+ * v2 smart http; do not consume version packet, which will
+ * be handled elsewhere.
+ */
+ d->proto_git = 1;
+ } else if (skip_prefix(line, "ERR ", &p)) {
+ die(_("remote error: %s"), p);
+ } else {
+ die("invalid server response; got '%s'", line);
+ }
+}
+
static struct discovery *discover_refs(const char *service, int for_push)
{
- struct strbuf exp = STRBUF_INIT;
struct strbuf type = STRBUF_INIT;
struct strbuf charset = STRBUF_INIT;
struct strbuf buffer = STRBUF_INIT;
@@ -405,38 +457,8 @@ static struct discovery *discover_refs(const char
*service, int for_push)
last->buf_alloc = strbuf_detach(&buffer, &last->len);
last->buf = last->buf_alloc;
- strbuf_addf(&exp, "application/x-%s-advertisement", service);
- if (maybe_smart &&
- (5 <= last->len && last->buf[4] == '#') &&
- !strbuf_cmp(&exp, &type)) {
- char *line;
-
- /*
- * smart HTTP response; validate that the service
- * pkt-line matches our request.
- */
- line = packet_read_line_buf(&last->buf, &last->len, NULL);
- if (!line)
- die("invalid server response; expected service, got
flush packet");
-
- strbuf_reset(&exp);
- strbuf_addf(&exp, "# service=%s", service);
- if (strcmp(line, exp.buf))
- die("invalid server response; got '%s'", line);
- strbuf_release(&exp);
-
- /* The header can include additional metadata lines, up
- * until a packet flush marker. Ignore these now, but
- * in the future we might start to scan them.
- */
- while (packet_read_line_buf(&last->buf, &last->len, NULL))
- ;
-
- last->proto_git = 1;
- } else if (maybe_smart &&
- last->len > 5 && starts_with(last->buf + 4, "version 2")) {
- last->proto_git = 1;
- }
+ if (maybe_smart)
+ check_smart_http(last, service, &type);
if (last->proto_git)
last->refs = parse_git_refs(last, for_push);
@@ -444,7 +466,6 @@ static struct discovery *discover_refs(const char *service,
int for_push)
last->refs = parse_info_refs(last);
strbuf_release(&refs_url);
- strbuf_release(&exp);
strbuf_release(&type);
strbuf_release(&charset);
strbuf_release(&effective_url);
