In order to allow for better control flow when protocol_v2 is introduced
convert 'get_remote_heads()' to use 'struct packet_reader' to read
packet lines. This enables a client to be able to peek the first line
of a server's response (without consuming it) in order to determine the
protocol version its speaking and then passing control to the
appropriate handler.
This is needed because the initial response from a server speaking
protocol_v0 includes the first ref, while subsequent protocol versions
respond with a version line. We want to be able to read this first line
without consuming the first ref sent in the protocol_v0 case so that the
protocol version the server is speaking can be determined outside of
'get_remote_heads()' in a future patch.
Signed-off-by: Brandon Williams <bmw...@google.com>
---
connect.c | 174 ++++++++++++++++++++++++++++++++++----------------------------
1 file changed, 96 insertions(+), 78 deletions(-)
diff --git a/connect.c b/connect.c
index c3a014c5b..00e90075c 100644
--- a/connect.c
+++ b/connect.c
@@ -48,6 +48,12 @@ int check_ref_type(const struct ref *ref, int flags)
static void die_initial_contact(int unexpected)
{
+ /*
+ * A hang-up after seeing some response from the other end
+ * means that it is unexpected, as we know the other end is
+ * willing to talk to us. A hang-up before seeing any
+ * response does not necessarily mean an ACL problem, though.
+ */
if (unexpected)
die(_("The remote end hung up upon initial contact"));
else
@@ -56,6 +62,41 @@ static void die_initial_contact(int unexpected)
"and the repository exists."));
}
+static enum protocol_version discover_version(struct packet_reader *reader)
+{
+ enum protocol_version version = protocol_unknown_version;
+
+ /*
+ * Peek the first line of the server's response to
+ * determine the protocol version the server is speaking.
+ */
+ switch (packet_reader_peek(reader)) {
+ case PACKET_READ_EOF:
+ die_initial_contact(0);
+ case PACKET_READ_FLUSH:
+ case PACKET_READ_DELIM:
+ version = protocol_v0;
+ break;
+ case PACKET_READ_NORMAL:
+ version = determine_protocol_version_client(reader->line);
+ break;
+ }
+
+ /* Maybe process capabilities here, at least for v2 */
+ switch (version) {
+ case protocol_v1:
+ /* Read the peeked version line */
+ packet_reader_read(reader);
+ break;
+ case protocol_v0:
+ break;
+ case protocol_unknown_version:
+ die("unknown protocol version: '%s'\n", reader->line);
+ }
+
+ return version;
+}
+
static void parse_one_symref_info(struct string_list *symref, const char *val,
int len)
{
char *sym, *target;
@@ -109,60 +150,21 @@ 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)
+static void process_capabilities(const char *line, int *len)
{
- 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_PROTOCOL_VERSION 0
-#define EXPECTING_FIRST_REF 1
-#define EXPECTING_REF 2
-#define EXPECTING_SHALLOW 3
-
-/* Returns 1 if packet_buffer is a protocol version pkt-line, 0 otherwise. */
-static int process_protocol_version(void)
-{
- switch (determine_protocol_version_client(packet_buffer)) {
- case protocol_v1:
- return 1;
- case protocol_v0:
- return 0;
- default:
- die("server is speaking an unknown protocol");
- }
-}
-
-static void process_capabilities(int *len)
-{
- int nul_location = strlen(packet_buffer);
+ int nul_location = strlen(line);
if (nul_location == *len)
return;
- server_capabilities = xstrdup(packet_buffer + nul_location + 1);
+ server_capabilities = xstrdup(line + nul_location + 1);
*len = nul_location;
}
-static int process_dummy_ref(void)
+static int process_dummy_ref(const char *line)
{
struct object_id oid;
const char *name;
- if (parse_oid_hex(packet_buffer, &oid, &name))
+ if (parse_oid_hex(line, &oid, &name))
return 0;
if (*name != ' ')
return 0;
@@ -171,20 +173,20 @@ static int process_dummy_ref(void)
return !oidcmp(&null_oid, &oid) && !strcmp(name, "capabilities^{}");
}
-static void check_no_capabilities(int len)
+static void check_no_capabilities(const char *line, int len)
{
- if (strlen(packet_buffer) != len)
+ if (strlen(line) != len)
warning("Ignoring capabilities after first line '%s'",
- packet_buffer + strlen(packet_buffer));
+ line + strlen(line));
}
-static int process_ref(int len, struct ref ***list, unsigned int flags,
- struct oid_array *extra_have)
+static int process_ref(const char *line, int len, struct ref ***list,
+ unsigned int flags, struct oid_array *extra_have)
{
struct object_id old_oid;
const char *name;
- if (parse_oid_hex(packet_buffer, &old_oid, &name))
+ if (parse_oid_hex(line, &old_oid, &name))
return 0;
if (*name != ' ')
return 0;
@@ -200,16 +202,17 @@ static int process_ref(int len, struct ref ***list,
unsigned int flags,
**list = ref;
*list = &ref->next;
}
- check_no_capabilities(len);
+ check_no_capabilities(line, len);
return 1;
}
-static int process_shallow(int len, struct oid_array *shallow_points)
+static int process_shallow(const char *line, int len,
+ struct oid_array *shallow_points)
{
const char *arg;
struct object_id old_oid;
- if (!skip_prefix(packet_buffer, "shallow ", &arg))
+ if (!skip_prefix(line, "shallow ", &arg))
return 0;
if (get_oid_hex(arg, &old_oid))
@@ -217,10 +220,17 @@ static int process_shallow(int len, struct oid_array
*shallow_points)
if (!shallow_points)
die("repository on the other end cannot be shallow");
oid_array_append(shallow_points, &old_oid);
- check_no_capabilities(len);
+ check_no_capabilities(line, len);
return 1;
}
+enum get_remote_heads_state {
+ EXPECTING_FIRST_REF = 0,
+ EXPECTING_REF,
+ EXPECTING_SHALLOW,
+ EXPECTING_DONE,
+};
+
/*
* Read all the refs from the other end
*/
@@ -230,47 +240,55 @@ struct ref **get_remote_heads(int in, char *src_buf,
size_t src_len,
struct oid_array *shallow_points)
{
struct ref **orig_list = list;
+ int len = 0;
+ enum get_remote_heads_state state = EXPECTING_FIRST_REF;
+ struct packet_reader reader;
+ const char *arg;
- /*
- * A hang-up after seeing some response from the other end
- * means that it is unexpected, as we know the other end is
- * willing to talk to us. A hang-up before seeing any
- * response does not necessarily mean an ACL problem, though.
- */
- int responded = 0;
- int len;
- int state = EXPECTING_PROTOCOL_VERSION;
+ packet_reader_init(&reader, in, src_buf, src_len,
+ PACKET_READ_CHOMP_NEWLINE |
+ PACKET_READ_GENTLE_ON_EOF);
+
+ discover_version(&reader);
*list = NULL;
- while ((len = read_remote_ref(in, &src_buf, &src_len, &responded))) {
+ while (state != EXPECTING_DONE) {
+ switch (packet_reader_read(&reader)) {
+ case PACKET_READ_EOF:
+ die_initial_contact(1);
+ case PACKET_READ_NORMAL:
+ len = reader.pktlen;
+ if (len > 4 && skip_prefix(reader.line, "ERR ", &arg))
+ die("remote error: %s", arg);
+ break;
+ case PACKET_READ_FLUSH:
+ state = EXPECTING_DONE;
+ break;
+ case PACKET_READ_DELIM:
+ die("invalid packet");
+ }
+
switch (state) {
- case EXPECTING_PROTOCOL_VERSION:
- if (process_protocol_version()) {
- state = EXPECTING_FIRST_REF;
- break;
- }
- state = EXPECTING_FIRST_REF;
- /* fallthrough */
case EXPECTING_FIRST_REF:
- process_capabilities(&len);
- if (process_dummy_ref()) {
+ process_capabilities(reader.line, &len);
+ if (process_dummy_ref(reader.line)) {
state = EXPECTING_SHALLOW;
break;
}
state = EXPECTING_REF;
/* fallthrough */
case EXPECTING_REF:
- if (process_ref(len, &list, flags, extra_have))
+ if (process_ref(reader.line, len, &list, flags,
extra_have))
break;
state = EXPECTING_SHALLOW;
/* fallthrough */
case EXPECTING_SHALLOW:
- if (process_shallow(len, shallow_points))
+ if (process_shallow(reader.line, len, shallow_points))
break;
- die("protocol error: unexpected '%s'", packet_buffer);
- default:
- die("unexpected state %d", state);
+ die("protocol error: unexpected '%s'", reader.line);
+ case EXPECTING_DONE:
+ break;
}
}
--
2.16.0.rc1.238.g530d649a79-goog
