On Tue, Jan 2, 2018 at 4:18 PM, Brandon Williams <bmw...@google.com> wrote:
> Introduce the 'fetch' server command.
>
> Signed-off-by: Brandon Williams <bmw...@google.com>
> ---
> Documentation/technical/protocol-v2.txt | 14 ++
> serve.c | 2 +
> upload-pack.c | 290
> ++++++++++++++++++++++++++++++++
> upload-pack.h | 9 +
> 4 files changed, 315 insertions(+)
> create mode 100644 upload-pack.h
>
> diff --git a/Documentation/technical/protocol-v2.txt
> b/Documentation/technical/protocol-v2.txt
> index 5f4d0e719..2a8e2f226 100644
> --- a/Documentation/technical/protocol-v2.txt
> +++ b/Documentation/technical/protocol-v2.txt
> @@ -115,3 +115,17 @@ The output of ls-refs is as follows:
>
> symref = PKT-LINE("symref" SP symbolic-ref SP resolved-ref LF)
> shallow = PKT-LINE("shallow" SP obj-id LF)
> +
> + Fetch
> +-------
> +
> +Fetch will need to be a modified version of the v1 fetch protocol. Some
> +potential areas for improvement are: Ref-in-want, CDN offloading,
> +Fetch-options.
> +
> +Since we'll have an 'ls-ref' service we can eliminate the need of fetch
> +to perform a ref-advertisement, instead a client can run the 'ls-refs'
> +service first, in order to find out what refs the server has, and then
> +request those refs directly using the fetch service.
> +
> +//TODO Flesh out the design
TODO: actually do it. ;)
a couple notes from the discussion in office:
* Could we split fetch into multiple phases
(negotiation + getting the pack)
* negotiation could be reused in forced push to
minimize the pack to be sent
* negotiation in a half duplex is actually better
called 'discovery', which discovers about the set
of objects available on the remote side.
(the opposite would be reveal, or 'ask-for-discovery', which
is could be used for a symmetric design of fetch and push)
> diff --git a/serve.c b/serve.c
> index 88d548410..ca3bb7190 100644
> --- a/serve.c
> +++ b/serve.c
> @@ -6,6 +6,7 @@
> #include "argv-array.h"
> #include "ls-refs.h"
> #include "serve.h"
> +#include "upload-pack.h"
>
> static int always_advertise(struct repository *r,
> struct strbuf *value)
> @@ -46,6 +47,7 @@ static struct protocol_capability capabilities[] = {
> { "agent", agent_advertise, NULL },
> { "stateless-rpc", always_advertise, NULL },
> { "ls-refs", always_advertise, ls_refs },
> + { "fetch", always_advertise, upload_pack_v2 },
> };
>
> static void advertise_capabilities(void)
> diff --git a/upload-pack.c b/upload-pack.c
> index 2ca60d27c..c41f6f528 100644
> --- a/upload-pack.c
> +++ b/upload-pack.c
> @@ -20,6 +20,7 @@
> #include "prio-queue.h"
> #include "protocol.h"
> #include "serve.h"
> +#include "upload-pack.h"
>
> static const char * const upload_pack_usage[] = {
> N_("git upload-pack [<options>] <dir>"),
> @@ -1040,6 +1041,295 @@ static void upload_pack(void)
> }
> }
>
> +struct upload_pack_data {
> + struct object_array wants;
> + struct oid_array haves;
> +
> + unsigned stateless_rpc : 1;
> +
> + unsigned use_thin_pack : 1;
> + unsigned use_ofs_delta : 1;
> + unsigned no_progress : 1;
> + unsigned use_include_tag : 1;
> + unsigned done : 1;
> +};
> +
> +#define UPLOAD_PACK_DATA_INIT { OBJECT_ARRAY_INIT, OID_ARRAY_INIT, 0, 0, 0,
> 0, 0, 0 }
> +
> +static void upload_pack_data_clear(struct upload_pack_data *data)
> +{
> + object_array_clear(&data->wants);
> + oid_array_clear(&data->haves);
> +}
> +
> +static int parse_want(const char *line)
> +{
> + const char *arg;
> + if (skip_prefix(line, "want ", &arg)) {
> + struct object_id oid;
> + struct object *o;
> +
> + if (get_oid_hex(arg, &oid))
> + die("git upload-pack: protocol error, "
> + "expected to get oid, not '%s'", line);
> +
> + o = parse_object(&oid);
> + if (!o) {
> + packet_write_fmt(1,
> + "ERR upload-pack: not our ref %s",
> + oid_to_hex(&oid));
> + die("git upload-pack: not our ref %s",
> + oid_to_hex(&oid));
> + }
> +
> + if (!(o->flags & WANTED)) {
> + o->flags |= WANTED;
> + add_object_array(o, NULL, &want_obj);
> + }
> +
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static int parse_have(const char *line, struct oid_array *haves)
> +{
> + const char *arg;
> + if (skip_prefix(line, "have ", &arg)) {
> + struct object_id oid;
> +
> + if (get_oid_hex(arg, &oid))
> + die("git upload-pack: expected SHA1 object, got
> '%s'", arg);
> + oid_array_append(haves, &oid);
> + return 1;
> + }
The same stylistic nit as in an earlier patch: Maybe
shortcircuit by inverting the condition?
> +
> + return 0;
> +}
> +
> +static void process_args(struct argv_array *args, struct upload_pack_data
> *data)
> +{
> + int i;
> +
> + for (i = 0; i < args->argc; i++) {
> + const char *arg = args->argv[i];
> +
> + /* process want */
> + if (parse_want(arg))
> + continue;
> + /* process have line */
> + if (parse_have(arg, &data->haves))
> + continue;
> +
> + /* process args like thin-pack */
> + if (!strcmp(arg, "thin-pack")) {
> + use_thin_pack = 1;
> + continue;
> + }
> + if (!strcmp(arg, "ofs-delta")) {
> + use_ofs_delta = 1;
> + continue;
> + }
> + if (!strcmp(arg, "no-progress")) {
> + no_progress = 1;
> + continue;
> + }
> + if (!strcmp(arg, "include-tag")) {
> + use_include_tag = 1;
> + continue;
> + }
> + if (!strcmp(arg, "done")) {
> + data->done = 1;
> + continue;
> + }
> +
> + /* ignore unknown lines maybe? */
> + die("unexpect line: '%s'", arg);
> + }
> +}
> +
> +static void read_haves(struct upload_pack_data *data)
> +{
> + struct packet_reader reader;
> + packet_reader_init(&reader, 0, NULL, 0,
> + PACKET_READ_CHOMP_NEWLINE);
> +
> + while (packet_reader_read(&reader) == PACKET_READ_NORMAL) {
> +
> + if (parse_have(reader.line, &data->haves))
> + continue;
> + if (!strcmp(reader.line, "done")) {
> + data->done = 1;
> + continue;
> + }
> + }
> + if (reader.status != PACKET_READ_FLUSH)
> + die("ERROR");
> +}
> +
> +static int process_haves(struct oid_array *haves, struct oid_array *common)
> +{
> + int i;
> +
> + /* Process haves */
> + for (i = 0; i < haves->nr; i++) {
> + const struct object_id *oid = &haves->oid[i];
> + struct object *o;
> + int we_knew_they_have = 0;
> +
> + if (!has_object_file(oid))
> + continue;
> +
> + oid_array_append(common, oid);
> +
> + o = parse_object(oid);
> + if (!o)
> + die("oops (%s)", oid_to_hex(oid));
> + if (o->type == OBJ_COMMIT) {
> + struct commit_list *parents;
> + struct commit *commit = (struct commit *)o;
> + if (o->flags & THEY_HAVE)
> + we_knew_they_have = 1;
> + else
> + o->flags |= THEY_HAVE;
> + if (!oldest_have || (commit->date < oldest_have))
> + oldest_have = commit->date;
> + for (parents = commit->parents;
> + parents;
> + parents = parents->next)
> + parents->item->object.flags |= THEY_HAVE;
> + }
> + if (!we_knew_they_have)
> + add_object_array(o, NULL, &have_obj);
> + }
> +
> + return 0;
> +}
> +
> +static int send_acks(struct oid_array *acks, struct strbuf *response)
> +{
> + int i;
> + /* Send Acks */
> + if (!acks->nr)
> + packet_buf_write(response, "NAK\n");
> +
> + for (i = 0; i < acks->nr; i++) {
> + packet_buf_write(response, "ACK %s common\n",
> + oid_to_hex(&acks->oid[i]));
> + }
> +
> + if (ok_to_give_up()) {
> + /* Send Ready */
> + packet_buf_write(response, "ACK %s ready\n",
> + oid_to_hex(&acks->oid[i-1]));
> + return 1;
> + }
> +
> + return 0;
> +}
> +
> +static int process_haves_and_send_acks(struct upload_pack_data *data)
> +{
> + struct oid_array common = OID_ARRAY_INIT;
> + struct strbuf response = STRBUF_INIT;
> + int ret = 0;
> +
> + process_haves(&data->haves, &common);
> + if (data->done) {
> + ret = 1;
> + } else if (send_acks(&common, &response)) {
> + packet_buf_delim(&response);
> + ret = 1;
> + } else {
> + /* Add Flush */
> + packet_buf_flush(&response);
> + ret = 0;
> + }
> +
> + /* Send response */
> + write_or_die(1, response.buf, response.len);
> + strbuf_release(&response);
> +
> + oid_array_clear(&data->haves);
> + oid_array_clear(&common);
> + return ret;
> +}
> +
> +#define FETCH_PROCESS_ARGS 0
> +#define FETCH_READ_HAVES 1
> +#define FETCH_SEND_ACKS 2
> +#define FETCH_SEND_PACK 3
> +#define FETCH_DONE 4
> +
> +int upload_pack_v2(struct repository *r, struct argv_array *keys,
> + struct argv_array *args)
> +{
> + int state = FETCH_PROCESS_ARGS;
> + struct upload_pack_data data = UPLOAD_PACK_DATA_INIT;
> + const char *out;
> + use_sideband = LARGE_PACKET_MAX;
> +
> + /* Check if cmd is being run as a stateless-rpc */
> + if (has_capability(keys, "stateless-rpc", &out))
> + if (!strcmp(out, "true"))
> + data.stateless_rpc = 1;
> +
> + while (state != FETCH_DONE) {
> + switch (state) {
> + case FETCH_PROCESS_ARGS:
> + process_args(args, &data);
> +
> + if (!want_obj.nr) {
> + /*
> + * Request didn't contain any 'want' lines,
> + * guess they didn't want anything.
> + */
> + state = FETCH_DONE;
> + } else if (data.haves.nr) {
> + /*
> + * Request had 'have' lines, so lets ACK them.
> + */
> + state = FETCH_SEND_ACKS;
> + } else {
> + /*
> + * Request had 'want's but no 'have's so we
> can
> + * immedietly go to construct and send a pack.
> + */
> + state = FETCH_SEND_PACK;
> + }
> + break;
> + case FETCH_READ_HAVES:
> + read_haves(&data);
> + state = FETCH_SEND_ACKS;
> + break;
> + case FETCH_SEND_ACKS:
> + if (process_haves_and_send_acks(&data))
> + state = FETCH_SEND_PACK;
> + else if (data.stateless_rpc)
> + /*
> + * Request was made via stateless-rpc and a
> + * packfile isn't ready to be created and
> sent.
> + */
> + state = FETCH_DONE;
> + else
> + state = FETCH_READ_HAVES;
> + break;
> + case FETCH_SEND_PACK:
> + create_pack_file();
> + state = FETCH_DONE;
> + break;
> + case FETCH_DONE:
> + break;
> + default:
> + BUG("invalid state");
> + }
> + }
> +
> + upload_pack_data_clear(&data);
> + return 0;
> +}
> +
> static int upload_pack_config(const char *var, const char *value, void
> *unused)
> {
> if (!strcmp("uploadpack.allowtipsha1inwant", var)) {
> diff --git a/upload-pack.h b/upload-pack.h
> new file mode 100644
> index 000000000..54c429563
> --- /dev/null
> +++ b/upload-pack.h
> @@ -0,0 +1,9 @@
> +#ifndef UPLOAD_PACK_H
> +#define UPLOAD_PACK_H
> +
> +struct repository;
> +struct argv_array;
> +extern int upload_pack_v2(struct repository *r, struct argv_array *keys,
> + struct argv_array *args);
> +
> +#endif /* UPLOAD_PACK_H */
> --
> 2.15.1.620.gb9897f4670-goog
>
