On 09/21, Jonathan Tan wrote:
> Currently, get_remote_heads() parses the ref advertisement in one loop,
> allowing refs and shallow lines to intersperse, despite this not being
> allowed by the specification. Refactor get_remote_heads() to use two
> loops instead, enforcing that refs come first, and then shallows.
>
> This also makes it easier to teach get_remote_heads() to interpret other
> lines in the ref advertisement, which will be done in a subsequent
> patch.
>
> Signed-off-by: Jonathan Tan <jonathantanmy@xxxxxxxxxx>
> ---
> In some in-office discussion, I was informed that my original patch
> relaxed the ordering of ".keep" lines. Here is an update.
>
> I'm also using a switch statement now, which avoids having multiple
> lines of read_remote_ref().
Looks cleaner than the last patch.
>
> connect.c | 159 ++++++++++++++++++++++++++++++++++++--------------------------
> 1 file changed, 93 insertions(+), 66 deletions(-)
>
> diff --git a/connect.c b/connect.c
> index 49b28b83b..e0821dbff 100644
> --- a/connect.c
> +++ b/connect.c
> @@ -107,6 +107,84 @@ static void annotate_refs_with_symref_info(struct ref *ref)
> string_list_clear(&symref, 0);
> }
>
> +/*
> + * Read one line of a server's ref advertisement into packet_buffer.
> + */
> +static int read_remote_ref(int in, char **src_buf, size_t *src_len,
> + int *responded)
> +{
> + int len = packet_read(in, src_buf, src_len,
> + packet_buffer, sizeof(packet_buffer),
> + PACKET_READ_GENTLE_ON_EOF |
> + PACKET_READ_CHOMP_NEWLINE);
> + const char *arg;
> + if (len < 0)
> + die_initial_contact(*responded);
> + if (len > 4 && skip_prefix(packet_buffer, "ERR ", &arg))
> + die("remote error: %s", arg);
> +
> + *responded = 1;
> +
> + return len;
> +}
> +
> +#define EXPECTING_REF 0
> +#define EXPECTING_SHALLOW 1
> +
> +static int process_ref(int *state, int len, struct ref ***list,
> + unsigned int flags, struct oid_array *extra_have)
> +{
> + struct object_id old_oid;
> + char *name;
> + int name_len;
> +
> + if (len < GIT_SHA1_HEXSZ + 2 ||
> + get_oid_hex(packet_buffer, &old_oid) ||
> + packet_buffer[GIT_SHA1_HEXSZ] != ' ') {
> + (*state)++;
I think it may be cleaner if the state variable is updated outside of
this function based on a return value from this function.
> + return 0;
> + }
> +
> + name = packet_buffer + GIT_SHA1_HEXSZ + 1;
> + name_len = strlen(name);
> + if (len != name_len + GIT_SHA1_HEXSZ + 1) {
> + free(server_capabilities);
> + server_capabilities = xstrdup(name + name_len + 1);
> + }
> +
> + if (extra_have && !strcmp(name, ".have")) {
> + oid_array_append(extra_have, &old_oid);
> + } else if (!strcmp(name, "capabilities^{}")) {
> + if (**list)
> + /* cannot coexist with other refs */
> + die("protocol error: unexpected capabilities^{}");
> + /* There should be no more refs; proceed to the next state. */
> + (*state)++;
> + } else if (check_ref(name, flags)) {
> + struct ref *ref = alloc_ref(name);
> + oidcpy(&ref->old_oid, &old_oid);
> + **list = ref;
> + *list = &ref->next;
> + }
> + return 1;
> +}
> +
> +static int process_shallow(int *state, struct oid_array *shallow_points)
state isn't needed here and could be dropped from the parameter list.
> +{
> + const char *arg;
> + struct object_id old_oid;
> +
> + if (!skip_prefix(packet_buffer, "shallow ", &arg))
> + return 0;
> +
> + if (get_oid_hex(arg, &old_oid))
> + die("protocol error: expected shallow sha-1, got '%s'", arg);
> + if (!shallow_points)
> + die("repository on the other end cannot be shallow");
> + oid_array_append(shallow_points, &old_oid);
> + return 1;
> +}
> +
> /*
> * Read all the refs from the other end
> */
> @@ -123,76 +201,25 @@ struct ref **get_remote_heads(int in, char *src_buf, size_t src_len,
> * willing to talk to us. A hang-up before seeing any
> * response does not necessarily mean an ACL problem, though.
> */
> - int saw_response;
> - int got_dummy_ref_with_capabilities_declaration = 0;
> + int responded = 0;
> + int len;
> + int state = EXPECTING_REF;
>
> *list = NULL;
> - for (saw_response = 0; ; saw_response = 1) {
> - struct ref *ref;
> - struct object_id old_oid;
> - char *name;
> - int len, name_len;
> - char *buffer = packet_buffer;
> - const char *arg;
> -
> - len = packet_read(in, &src_buf, &src_len,
> - packet_buffer, sizeof(packet_buffer),
> - PACKET_READ_GENTLE_ON_EOF |
> - PACKET_READ_CHOMP_NEWLINE);
> - if (len < 0)
> - die_initial_contact(saw_response);
> -
> - if (!len)
> - break;
> -
> - if (len > 4 && skip_prefix(buffer, "ERR ", &arg))
> - die("remote error: %s", arg);
> -
> - if (len == GIT_SHA1_HEXSZ + strlen("shallow ") &&
> - skip_prefix(buffer, "shallow ", &arg)) {
> - if (get_oid_hex(arg, &old_oid))
> - die("protocol error: expected shallow sha-1, got '%s'", arg);
> - if (!shallow_points)
> - die("repository on the other end cannot be shallow");
> - oid_array_append(shallow_points, &old_oid);
> - continue;
> - }
> -
> - if (len < GIT_SHA1_HEXSZ + 2 || get_oid_hex(buffer, &old_oid) ||
> - buffer[GIT_SHA1_HEXSZ] != ' ')
> - die("protocol error: expected sha/ref, got '%s'", buffer);
> - name = buffer + GIT_SHA1_HEXSZ + 1;
> -
> - name_len = strlen(name);
> - if (len != name_len + GIT_SHA1_HEXSZ + 1) {
> - free(server_capabilities);
> - server_capabilities = xstrdup(name + name_len + 1);
> - }
>
> - if (extra_have && !strcmp(name, ".have")) {
> - oid_array_append(extra_have, &old_oid);
> - continue;
> - }
> -
> - if (!strcmp(name, "capabilities^{}")) {
> - if (saw_response)
> - die("protocol error: unexpected capabilities^{}");
> - if (got_dummy_ref_with_capabilities_declaration)
> - die("protocol error: multiple capabilities^{}");
> - got_dummy_ref_with_capabilities_declaration = 1;
> - continue;
> + while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) {
> + switch (state) {
> + case EXPECTING_REF:
> + if (process_ref(&state, len, &list, flags, extra_have))
> + break;
> + /* fallthrough */
> + case EXPECTING_SHALLOW:
> + if (process_shallow(&state, shallow_points))
> + break;
> + die("protocol error: unexpected '%s'", packet_buffer);
> + default:
> + die("unexpected state %d", state);
> }
> -
> - if (!check_ref(name, flags))
> - continue;
> -
> - if (got_dummy_ref_with_capabilities_declaration)
> - die("protocol error: unexpected ref after capabilities^{}");
> -
> - ref = alloc_ref(buffer + GIT_SHA1_HEXSZ + 1);
> - oidcpy(&ref->old_oid, &old_oid);
> - *list = ref;
> - list = &ref->next;
> }
>
> annotate_refs_with_symref_info(*orig_list);
> --
> 2.14.1.728.g20a5b67d5.dirty
>
--
Brandon Williams
