[PATCH v2 2/6] upload-pack: send symbolic ref information as capability
One long-standing flaw in the pack transfer protocol was that there was no way to tell the other end which branch "HEAD" points at. With a new "sym" capability (e.g. "sym=HEAD:refs/heads/master"; can be repeated more than once to represent symbolic refs other than HEAD, such as "refs/remotes/origin/HEAD").
Add an infrastructure to collect symbolic refs, format them as extra capabilities and put it on the wire. For now, just send information on the "HEAD" and nothing else.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
upload-pack.c | 48 +++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 43 insertions(+), 5 deletions(-)
Show changes to upload-pack.c +43 −5
diff --git a/upload-pack.c b/upload-pack.c
index a6e107f..53958b9 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -734,6 +734,16 @@ static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag
return 0;
}
+static void format_symref_info(struct strbuf *buf, struct string_list *symref)
+{
+ struct string_list_item *item;
+
+ if (!symref->nr)
+ return;
+ for_each_string_list_item(item, symref)
+ strbuf_addf(buf, " sym=%s:%s", item->string, (char *)item->util);
+}
+
static int send_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
static const char *capabilities = "multi_ack thin-pack side-band"
@@ -745,32 +755,60 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo
if (mark_our_ref(refname, sha1, flag, NULL))
return 0;
- if (capabilities)
- packet_write(1, "%s %s%c%s%s%s agent=%s\n",
+ if (capabilities) {
+ struct strbuf symref_info = STRBUF_INIT;
+
+ format_symref_info(&symref_info, cb_data);
+ packet_write(1, "%s %s%c%s%s%s%s agent=%s\n",
sha1_to_hex(sha1), refname_nons,
0, capabilities,
allow_tip_sha1_in_want ? " allow-tip-sha1-in-want" : "",
stateless_rpc ? " no-done" : "",
+ symref_info.buf,
git_user_agent_sanitized());
- else
+ strbuf_release(&symref_info);
+ } else {
packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
+ }
capabilities = NULL;
if (!peel_ref(refname, peeled))
packet_write(1, "%s %s^{}\n", sha1_to_hex(peeled), refname_nons);
return 0;
}
+static int find_symref(const char *refname, const unsigned char *sha1, int flag,
+ void *cb_data)
+{
+ const char *symref_target;
+ struct string_list_item *item;
+ unsigned char unused[20];
+
+ if ((flag & REF_ISSYMREF) == 0)
+ return 0;
+ symref_target = resolve_ref_unsafe(refname, unused, 0, &flag);
+ if (!symref_target || (flag & REF_ISSYMREF) == 0)
+ die("'%s' is a symref but it is not?", refname);
+ item = string_list_append(cb_data, refname);
+ item->util = xstrdup(symref_target);
+ return 0;
+}
+
static void upload_pack(void)
{
+ struct string_list symref = STRING_LIST_INIT_DUP;
+
+ head_ref_namespaced(find_symref, &symref);
+
if (advertise_refs || !stateless_rpc) {
reset_timeout();
- head_ref_namespaced(send_ref, NULL);
+ head_ref_namespaced(send_ref, &symref);
for_each_namespaced_ref(send_ref, NULL);
packet_flush(1);
} else {
- head_ref_namespaced(mark_our_ref, NULL);
+ head_ref_namespaced(mark_our_ref, &symref);
for_each_namespaced_ref(mark_our_ref, NULL);
}
+ string_list_clear(&symref, 1);
if (advertise_refs)
return;
--
1.8.4-585-g8d1dcaf
Andreas Krey
