upload-pack: refactor ok_to_give_up()

[git.git] / upload-pack.c

#include "cache.h"
#include "config.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "repository.h"
#include "object-store.h"
#include "tag.h"
#include "object.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "list-objects-filter.h"
#include "list-objects-filter-options.h"
#include "run-command.h"
#include "connect.h"
#include "sigchain.h"
#include "version.h"
#include "string-list.h"
#include "argv-array.h"
#include "prio-queue.h"
#include "protocol.h"
#include "quote.h"
#include "upload-pack.h"
#include "serve.h"

/* Remember to update object flag allocation in object.h */
#define THEY_HAVE       (1u << 11)
#define OUR_REF         (1u << 12)
#define WANTED          (1u << 13)
#define COMMON_KNOWN    (1u << 14)
#define REACHABLE       (1u << 15)

#define SHALLOW         (1u << 16)
#define NOT_SHALLOW     (1u << 17)
#define CLIENT_SHALLOW  (1u << 18)
#define HIDDEN_REF      (1u << 19)

static timestamp_t oldest_have;

static int deepen_relative;
static int multi_ack;
static int no_done;
static int use_thin_pack, use_ofs_delta, use_include_tag;
static int no_progress, daemon_mode;
/* Allow specifying sha1 if it is a ref tip. */
#define ALLOW_TIP_SHA1  01
/* Allow request of a sha1 if it is reachable from a ref (possibly hidden ref). */
#define ALLOW_REACHABLE_SHA1    02
/* Allow request of any sha1. Implies ALLOW_TIP_SHA1 and ALLOW_REACHABLE_SHA1. */
#define ALLOW_ANY_SHA1  07
static unsigned int allow_unadvertised_object_request;
static int shallow_nr;
static struct object_array have_obj;
static struct object_array want_obj;
static struct object_array extra_edge_obj;
static unsigned int timeout;
static int keepalive = 5;
/* 0 for no sideband,
 * otherwise maximum packet size (up to 65520 bytes).
 */
static int use_sideband;
static int stateless_rpc;
static const char *pack_objects_hook;

static int filter_capability_requested;
static int allow_filter;
static struct list_objects_filter_options filter_options;

static void reset_timeout(void)
{
        alarm(timeout);
}

static void send_client_data(int fd, const char *data, ssize_t sz)
{
        if (use_sideband) {
                send_sideband(1, fd, data, sz, use_sideband);
                return;
        }
        if (fd == 3)
                /* emergency quit */
                fd = 2;
        if (fd == 2) {
                /* XXX: are we happy to lose stuff here? */
                xwrite(fd, data, sz);
                return;
        }
        write_or_die(fd, data, sz);
}

static int write_one_shallow(const struct commit_graft *graft, void *cb_data)
{
        FILE *fp = cb_data;
        if (graft->nr_parent == -1)
                fprintf(fp, "--shallow %s\n", oid_to_hex(&graft->oid));
        return 0;
}

static void create_pack_file(void)
{
        struct child_process pack_objects = CHILD_PROCESS_INIT;
        char data[8193], progress[128];
        char abort_msg[] = "aborting due to possible repository "
                "corruption on the remote side.";
        int buffered = -1;
        ssize_t sz;
        int i;
        FILE *pipe_fd;

        if (!pack_objects_hook)
                pack_objects.git_cmd = 1;
        else {
                argv_array_push(&pack_objects.args, pack_objects_hook);
                argv_array_push(&pack_objects.args, "git");
                pack_objects.use_shell = 1;
        }

        if (shallow_nr) {
                argv_array_push(&pack_objects.args, "--shallow-file");
                argv_array_push(&pack_objects.args, "");
        }
        argv_array_push(&pack_objects.args, "pack-objects");
        argv_array_push(&pack_objects.args, "--revs");
        if (use_thin_pack)
                argv_array_push(&pack_objects.args, "--thin");

        argv_array_push(&pack_objects.args, "--stdout");
        if (shallow_nr)
                argv_array_push(&pack_objects.args, "--shallow");
        if (!no_progress)
                argv_array_push(&pack_objects.args, "--progress");
        if (use_ofs_delta)
                argv_array_push(&pack_objects.args, "--delta-base-offset");
        if (use_include_tag)
                argv_array_push(&pack_objects.args, "--include-tag");
        if (filter_options.filter_spec) {
                if (pack_objects.use_shell) {
                        struct strbuf buf = STRBUF_INIT;
                        sq_quote_buf(&buf, filter_options.filter_spec);
                        argv_array_pushf(&pack_objects.args, "--filter=%s", buf.buf);
                        strbuf_release(&buf);
                } else {
                        argv_array_pushf(&pack_objects.args, "--filter=%s",
                                         filter_options.filter_spec);
                }
        }

        pack_objects.in = -1;
        pack_objects.out = -1;
        pack_objects.err = -1;

        if (start_command(&pack_objects))
                die("git upload-pack: unable to fork git-pack-objects");

        pipe_fd = xfdopen(pack_objects.in, "w");

        if (shallow_nr)
                for_each_commit_graft(write_one_shallow, pipe_fd);

        for (i = 0; i < want_obj.nr; i++)
                fprintf(pipe_fd, "%s\n",
                        oid_to_hex(&want_obj.objects[i].item->oid));
        fprintf(pipe_fd, "--not\n");
        for (i = 0; i < have_obj.nr; i++)
                fprintf(pipe_fd, "%s\n",
                        oid_to_hex(&have_obj.objects[i].item->oid));
        for (i = 0; i < extra_edge_obj.nr; i++)
                fprintf(pipe_fd, "%s\n",
                        oid_to_hex(&extra_edge_obj.objects[i].item->oid));
        fprintf(pipe_fd, "\n");
        fflush(pipe_fd);
        fclose(pipe_fd);

        /* We read from pack_objects.err to capture stderr output for
         * progress bar, and pack_objects.out to capture the pack data.
         */

        while (1) {
                struct pollfd pfd[2];
                int pe, pu, pollsize;
                int ret;

                reset_timeout();

                pollsize = 0;
                pe = pu = -1;

                if (0 <= pack_objects.out) {
                        pfd[pollsize].fd = pack_objects.out;
                        pfd[pollsize].events = POLLIN;
                        pu = pollsize;
                        pollsize++;
                }
                if (0 <= pack_objects.err) {
                        pfd[pollsize].fd = pack_objects.err;
                        pfd[pollsize].events = POLLIN;
                        pe = pollsize;
                        pollsize++;
                }

                if (!pollsize)
                        break;

                ret = poll(pfd, pollsize,
                        keepalive < 0 ? -1 : 1000 * keepalive);

                if (ret < 0) {
                        if (errno != EINTR) {
                                error_errno("poll failed, resuming");
                                sleep(1);
                        }
                        continue;
                }
                if (0 <= pe && (pfd[pe].revents & (POLLIN|POLLHUP))) {
                        /* Status ready; we ship that in the side-band
                         * or dump to the standard error.
                         */
                        sz = xread(pack_objects.err, progress,
                                  sizeof(progress));
                        if (0 < sz)
                                send_client_data(2, progress, sz);
                        else if (sz == 0) {
                                close(pack_objects.err);
                                pack_objects.err = -1;
                        }
                        else
                                goto fail;
                        /* give priority to status messages */
                        continue;
                }
                if (0 <= pu && (pfd[pu].revents & (POLLIN|POLLHUP))) {
                        /* Data ready; we keep the last byte to ourselves
                         * in case we detect broken rev-list, so that we
                         * can leave the stream corrupted.  This is
                         * unfortunate -- unpack-objects would happily
                         * accept a valid packdata with trailing garbage,
                         * so appending garbage after we pass all the
                         * pack data is not good enough to signal
                         * breakage to downstream.
                         */
                        char *cp = data;
                        ssize_t outsz = 0;
                        if (0 <= buffered) {
                                *cp++ = buffered;
                                outsz++;
                        }
                        sz = xread(pack_objects.out, cp,
                                  sizeof(data) - outsz);
                        if (0 < sz)
                                ;
                        else if (sz == 0) {
                                close(pack_objects.out);
                                pack_objects.out = -1;
                        }
                        else
                                goto fail;
                        sz += outsz;
                        if (1 < sz) {
                                buffered = data[sz-1] & 0xFF;
                                sz--;
                        }
                        else
                                buffered = -1;
                        send_client_data(1, data, sz);
                }

                /*
                 * We hit the keepalive timeout without saying anything; send
                 * an empty message on the data sideband just to let the other
                 * side know we're still working on it, but don't have any data
                 * yet.
                 *
                 * If we don't have a sideband channel, there's no room in the
                 * protocol to say anything, so those clients are just out of
                 * luck.
                 */
                if (!ret && use_sideband) {
                        static const char buf[] = "0005\1";
                        write_or_die(1, buf, 5);
                }
        }

        if (finish_command(&pack_objects)) {
                error("git upload-pack: git-pack-objects died with error.");
                goto fail;
        }

        /* flush the data */
        if (0 <= buffered) {
                data[0] = buffered;
                send_client_data(1, data, 1);
                fprintf(stderr, "flushed.\n");
        }
        if (use_sideband)
                packet_flush(1);
        return;

 fail:
        send_client_data(3, abort_msg, sizeof(abort_msg));
        die("git upload-pack: %s", abort_msg);
}

static int got_oid(const char *hex, struct object_id *oid)
{
        struct object *o;
        int we_knew_they_have = 0;

        if (get_oid_hex(hex, oid))
                die("git upload-pack: expected SHA1 object, got '%s'", hex);
        if (!has_object_file(oid))
                return -1;

        o = parse_object(the_repository, 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 1;
        }
        return 0;
}

static int reachable(struct commit *from, unsigned int with_flag,
                     unsigned int assign_flag)
{
        struct prio_queue work = { compare_commits_by_commit_date };

        prio_queue_put(&work, from);
        while (work.nr) {
                struct commit_list *list;
                struct commit *commit = prio_queue_get(&work);

                if (commit->object.flags & with_flag) {
                        from->object.flags |= assign_flag;
                        break;
                }
                if (!commit->object.parsed)
                        parse_object(the_repository, &commit->object.oid);
                if (commit->object.flags & REACHABLE)
                        continue;
                commit->object.flags |= REACHABLE;
                if (commit->date < oldest_have)
                        continue;
                for (list = commit->parents; list; list = list->next) {
                        struct commit *parent = list->item;
                        if (!(parent->object.flags & REACHABLE))
                                prio_queue_put(&work, parent);
                }
        }
        from->object.flags |= REACHABLE;
        clear_commit_marks(from, REACHABLE);
        clear_prio_queue(&work);
        return (from->object.flags & assign_flag);
}

/*
 * Determine if every commit in 'from' can reach at least one commit
 * that is marked with 'with_flag'. As we traverse, use 'assign_flag'
 * as a marker for commits that are already visited.
 */
static int can_all_from_reach_with_flag(struct object_array *from,
                                        unsigned int with_flag,
                                        unsigned int assign_flag)
{
        int i;

        for (i = 0; i < from->nr; i++) {
                struct object *from_one = from->objects[i].item;

                if (from_one->flags & assign_flag)
                        continue;
                from_one = deref_tag(the_repository, from_one, "a from object", 0);
                if (!from_one || from_one->type != OBJ_COMMIT) {
                        /* no way to tell if this is reachable by
                         * looking at the ancestry chain alone, so
                         * leave a note to ourselves not to worry about
                         * this object anymore.
                         */
                        from->objects[i].item->flags |= assign_flag;
                        continue;
                }
                if (!reachable((struct commit *)from_one, with_flag, assign_flag))
                        return 0;
        }
        return 1;
}

static int ok_to_give_up(void)
{
        if (!have_obj.nr)
                return 0;

        return can_all_from_reach_with_flag(&want_obj, THEY_HAVE, COMMON_KNOWN);
}

static int get_common_commits(void)
{
        struct object_id oid;
        char last_hex[GIT_MAX_HEXSZ + 1];
        int got_common = 0;
        int got_other = 0;
        int sent_ready = 0;

        save_commit_buffer = 0;

        for (;;) {
                char *line = packet_read_line(0, NULL);
                const char *arg;

                reset_timeout();

                if (!line) {
                        if (multi_ack == 2 && got_common
                            && !got_other && ok_to_give_up()) {
                                sent_ready = 1;
                                packet_write_fmt(1, "ACK %s ready\n", last_hex);
                        }
                        if (have_obj.nr == 0 || multi_ack)
                                packet_write_fmt(1, "NAK\n");

                        if (no_done && sent_ready) {
                                packet_write_fmt(1, "ACK %s\n", last_hex);
                                return 0;
                        }
                        if (stateless_rpc)
                                exit(0);
                        got_common = 0;
                        got_other = 0;
                        continue;
                }
                if (skip_prefix(line, "have ", &arg)) {
                        switch (got_oid(arg, &oid)) {
                        case -1: /* they have what we do not */
                                got_other = 1;
                                if (multi_ack && ok_to_give_up()) {
                                        const char *hex = oid_to_hex(&oid);
                                        if (multi_ack == 2) {
                                                sent_ready = 1;
                                                packet_write_fmt(1, "ACK %s ready\n", hex);
                                        } else
                                                packet_write_fmt(1, "ACK %s continue\n", hex);
                                }
                                break;
                        default:
                                got_common = 1;
                                oid_to_hex_r(last_hex, &oid);
                                if (multi_ack == 2)
                                        packet_write_fmt(1, "ACK %s common\n", last_hex);
                                else if (multi_ack)
                                        packet_write_fmt(1, "ACK %s continue\n", last_hex);
                                else if (have_obj.nr == 1)
                                        packet_write_fmt(1, "ACK %s\n", last_hex);
                                break;
                        }
                        continue;
                }
                if (!strcmp(line, "done")) {
                        if (have_obj.nr > 0) {
                                if (multi_ack)
                                        packet_write_fmt(1, "ACK %s\n", last_hex);
                                return 0;
                        }
                        packet_write_fmt(1, "NAK\n");
                        return -1;
                }
                die("git upload-pack: expected SHA1 list, got '%s'", line);
        }
}

static int is_our_ref(struct object *o)
{
        int allow_hidden_ref = (allow_unadvertised_object_request &
                        (ALLOW_TIP_SHA1 | ALLOW_REACHABLE_SHA1));
        return o->flags & ((allow_hidden_ref ? HIDDEN_REF : 0) | OUR_REF);
}

/*
 * on successful case, it's up to the caller to close cmd->out
 */
static int do_reachable_revlist(struct child_process *cmd,
                                struct object_array *src,
                                struct object_array *reachable)
{
        static const char *argv[] = {
                "rev-list", "--stdin", NULL,
        };
        struct object *o;
        char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
        int i;

        cmd->argv = argv;
        cmd->git_cmd = 1;
        cmd->no_stderr = 1;
        cmd->in = -1;
        cmd->out = -1;

        /*
         * If the next rev-list --stdin encounters an unknown commit,
         * it terminates, which will cause SIGPIPE in the write loop
         * below.
         */
        sigchain_push(SIGPIPE, SIG_IGN);

        if (start_command(cmd))
                goto error;

        namebuf[0] = '^';
        namebuf[GIT_SHA1_HEXSZ + 1] = '\n';
        for (i = get_max_object_index(); 0 < i; ) {
                o = get_indexed_object(--i);
                if (!o)
                        continue;
                if (reachable && o->type == OBJ_COMMIT)
                        o->flags &= ~TMP_MARK;
                if (!is_our_ref(o))
                        continue;
                memcpy(namebuf + 1, oid_to_hex(&o->oid), GIT_SHA1_HEXSZ);
                if (write_in_full(cmd->in, namebuf, GIT_SHA1_HEXSZ + 2) < 0)
                        goto error;
        }
        namebuf[GIT_SHA1_HEXSZ] = '\n';
        for (i = 0; i < src->nr; i++) {
                o = src->objects[i].item;
                if (is_our_ref(o)) {
                        if (reachable)
                                add_object_array(o, NULL, reachable);
                        continue;
                }
                if (reachable && o->type == OBJ_COMMIT)
                        o->flags |= TMP_MARK;
                memcpy(namebuf, oid_to_hex(&o->oid), GIT_SHA1_HEXSZ);
                if (write_in_full(cmd->in, namebuf, GIT_SHA1_HEXSZ + 1) < 0)
                        goto error;
        }
        close(cmd->in);
        cmd->in = -1;
        sigchain_pop(SIGPIPE);

        return 0;

error:
        sigchain_pop(SIGPIPE);

        if (cmd->in >= 0)
                close(cmd->in);
        if (cmd->out >= 0)
                close(cmd->out);
        return -1;
}

static int get_reachable_list(struct object_array *src,
                              struct object_array *reachable)
{
        struct child_process cmd = CHILD_PROCESS_INIT;
        int i;
        struct object *o;
        char namebuf[GIT_MAX_HEXSZ + 2]; /* ^ + hash + LF */
        const unsigned hexsz = the_hash_algo->hexsz;

        if (do_reachable_revlist(&cmd, src, reachable) < 0)
                return -1;

        while ((i = read_in_full(cmd.out, namebuf, hexsz + 1)) == hexsz + 1) {
                struct object_id sha1;
                const char *p;

                if (parse_oid_hex(namebuf, &sha1, &p) || *p != '\n')
                        break;

                o = lookup_object(the_repository, sha1.hash);
                if (o && o->type == OBJ_COMMIT) {
                        o->flags &= ~TMP_MARK;
                }
        }
        for (i = get_max_object_index(); 0 < i; i--) {
                o = get_indexed_object(i - 1);
                if (o && o->type == OBJ_COMMIT &&
                    (o->flags & TMP_MARK)) {
                        add_object_array(o, NULL, reachable);
                                o->flags &= ~TMP_MARK;
                }
        }
        close(cmd.out);

        if (finish_command(&cmd))
                return -1;

        return 0;
}

static int has_unreachable(struct object_array *src)
{
        struct child_process cmd = CHILD_PROCESS_INIT;
        char buf[1];
        int i;

        if (do_reachable_revlist(&cmd, src, NULL) < 0)
                return 1;

        /*
         * The commits out of the rev-list are not ancestors of
         * our ref.
         */
        i = read_in_full(cmd.out, buf, 1);
        if (i)
                goto error;
        close(cmd.out);
        cmd.out = -1;

        /*
         * rev-list may have died by encountering a bad commit
         * in the history, in which case we do want to bail out
         * even when it showed no commit.
         */
        if (finish_command(&cmd))
                goto error;

        /* All the non-tip ones are ancestors of what we advertised */
        return 0;

error:
        sigchain_pop(SIGPIPE);
        if (cmd.out >= 0)
                close(cmd.out);
        return 1;
}

static void check_non_tip(void)
{
        int i;

        /*
         * In the normal in-process case without
         * uploadpack.allowReachableSHA1InWant,
         * non-tip requests can never happen.
         */
        if (!stateless_rpc && !(allow_unadvertised_object_request & ALLOW_REACHABLE_SHA1))
                goto error;
        if (!has_unreachable(&want_obj))
                /* All the non-tip ones are ancestors of what we advertised */
                return;

error:
        /* Pick one of them (we know there at least is one) */
        for (i = 0; i < want_obj.nr; i++) {
                struct object *o = want_obj.objects[i].item;
                if (!is_our_ref(o))
                        die("git upload-pack: not our ref %s",
                            oid_to_hex(&o->oid));
        }
}

static void send_shallow(struct commit_list *result)
{
        while (result) {
                struct object *object = &result->item->object;
                if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
                        packet_write_fmt(1, "shallow %s",
                                         oid_to_hex(&object->oid));
                        register_shallow(the_repository, &object->oid);
                        shallow_nr++;
                }
                result = result->next;
        }
}

static void send_unshallow(const struct object_array *shallows)
{
        int i;

        for (i = 0; i < shallows->nr; i++) {
                struct object *object = shallows->objects[i].item;
                if (object->flags & NOT_SHALLOW) {
                        struct commit_list *parents;
                        packet_write_fmt(1, "unshallow %s",
                                         oid_to_hex(&object->oid));
                        object->flags &= ~CLIENT_SHALLOW;
                        /*
                         * We want to _register_ "object" as shallow, but we
                         * also need to traverse object's parents to deepen a
                         * shallow clone. Unregister it for now so we can
                         * parse and add the parents to the want list, then
                         * re-register it.
                         */
                        unregister_shallow(&object->oid);
                        object->parsed = 0;
                        parse_commit_or_die((struct commit *)object);
                        parents = ((struct commit *)object)->parents;
                        while (parents) {
                                add_object_array(&parents->item->object,
                                                 NULL, &want_obj);
                                parents = parents->next;
                        }
                        add_object_array(object, NULL, &extra_edge_obj);
                }
                /* make sure commit traversal conforms to client */
                register_shallow(the_repository, &object->oid);
        }
}

static void deepen(int depth, int deepen_relative,
                   struct object_array *shallows)
{
        if (depth == INFINITE_DEPTH && !is_repository_shallow(the_repository)) {
                int i;

                for (i = 0; i < shallows->nr; i++) {
                        struct object *object = shallows->objects[i].item;
                        object->flags |= NOT_SHALLOW;
                }
        } else if (deepen_relative) {
                struct object_array reachable_shallows = OBJECT_ARRAY_INIT;
                struct commit_list *result;

                get_reachable_list(shallows, &reachable_shallows);
                result = get_shallow_commits(&reachable_shallows,
                                             depth + 1,
                                             SHALLOW, NOT_SHALLOW);
                send_shallow(result);
                free_commit_list(result);
                object_array_clear(&reachable_shallows);
        } else {
                struct commit_list *result;

                result = get_shallow_commits(&want_obj, depth,
                                             SHALLOW, NOT_SHALLOW);
                send_shallow(result);
                free_commit_list(result);
        }

        send_unshallow(shallows);
}

static void deepen_by_rev_list(int ac, const char **av,
                               struct object_array *shallows)
{
        struct commit_list *result;

        result = get_shallow_commits_by_rev_list(ac, av, SHALLOW, NOT_SHALLOW);
        send_shallow(result);
        free_commit_list(result);
        send_unshallow(shallows);
}

/* Returns 1 if a shallow list is sent or 0 otherwise */
static int send_shallow_list(int depth, int deepen_rev_list,
                             timestamp_t deepen_since,
                             struct string_list *deepen_not,
                             struct object_array *shallows)
{
        int ret = 0;

        if (depth > 0 && deepen_rev_list)
                die("git upload-pack: deepen and deepen-since (or deepen-not) cannot be used together");
        if (depth > 0) {
                deepen(depth, deepen_relative, shallows);
                ret = 1;
        } else if (deepen_rev_list) {
                struct argv_array av = ARGV_ARRAY_INIT;
                int i;

                argv_array_push(&av, "rev-list");
                if (deepen_since)
                        argv_array_pushf(&av, "--max-age=%"PRItime, deepen_since);
                if (deepen_not->nr) {
                        argv_array_push(&av, "--not");
                        for (i = 0; i < deepen_not->nr; i++) {
                                struct string_list_item *s = deepen_not->items + i;
                                argv_array_push(&av, s->string);
                        }
                        argv_array_push(&av, "--not");
                }
                for (i = 0; i < want_obj.nr; i++) {
                        struct object *o = want_obj.objects[i].item;
                        argv_array_push(&av, oid_to_hex(&o->oid));
                }
                deepen_by_rev_list(av.argc, av.argv, shallows);
                argv_array_clear(&av);
                ret = 1;
        } else {
                if (shallows->nr > 0) {
                        int i;
                        for (i = 0; i < shallows->nr; i++)
                                register_shallow(the_repository,
                                                 &shallows->objects[i].item->oid);
                }
        }

        shallow_nr += shallows->nr;
        return ret;
}

static int process_shallow(const char *line, struct object_array *shallows)
{
        const char *arg;
        if (skip_prefix(line, "shallow ", &arg)) {
                struct object_id oid;
                struct object *object;
                if (get_oid_hex(arg, &oid))
                        die("invalid shallow line: %s", line);
                object = parse_object(the_repository, &oid);
                if (!object)
                        return 1;
                if (object->type != OBJ_COMMIT)
                        die("invalid shallow object %s", oid_to_hex(&oid));
                if (!(object->flags & CLIENT_SHALLOW)) {
                        object->flags |= CLIENT_SHALLOW;
                        add_object_array(object, NULL, shallows);
                }
                return 1;
        }

        return 0;
}

static int process_deepen(const char *line, int *depth)
{
        const char *arg;
        if (skip_prefix(line, "deepen ", &arg)) {
                char *end = NULL;
                *depth = (int)strtol(arg, &end, 0);
                if (!end || *end || *depth <= 0)
                        die("Invalid deepen: %s", line);
                return 1;
        }

        return 0;
}

static int process_deepen_since(const char *line, timestamp_t *deepen_since, int *deepen_rev_list)
{
        const char *arg;
        if (skip_prefix(line, "deepen-since ", &arg)) {
                char *end = NULL;
                *deepen_since = parse_timestamp(arg, &end, 0);
                if (!end || *end || !deepen_since ||
                    /* revisions.c's max_age -1 is special */
                    *deepen_since == -1)
                        die("Invalid deepen-since: %s", line);
                *deepen_rev_list = 1;
                return 1;
        }
        return 0;
}

static int process_deepen_not(const char *line, struct string_list *deepen_not, int *deepen_rev_list)
{
        const char *arg;
        if (skip_prefix(line, "deepen-not ", &arg)) {
                char *ref = NULL;
                struct object_id oid;
                if (expand_ref(arg, strlen(arg), &oid, &ref) != 1)
                        die("git upload-pack: ambiguous deepen-not: %s", line);
                string_list_append(deepen_not, ref);
                free(ref);
                *deepen_rev_list = 1;
                return 1;
        }
        return 0;
}

static void receive_needs(void)
{
        struct object_array shallows = OBJECT_ARRAY_INIT;
        struct string_list deepen_not = STRING_LIST_INIT_DUP;
        int depth = 0;
        int has_non_tip = 0;
        timestamp_t deepen_since = 0;
        int deepen_rev_list = 0;

        shallow_nr = 0;
        for (;;) {
                struct object *o;
                const char *features;
                struct object_id oid_buf;
                char *line = packet_read_line(0, NULL);
                const char *arg;

                reset_timeout();
                if (!line)
                        break;

                if (process_shallow(line, &shallows))
                        continue;
                if (process_deepen(line, &depth))
                        continue;
                if (process_deepen_since(line, &deepen_since, &deepen_rev_list))
                        continue;
                if (process_deepen_not(line, &deepen_not, &deepen_rev_list))
                        continue;

                if (skip_prefix(line, "filter ", &arg)) {
                        if (!filter_capability_requested)
                                die("git upload-pack: filtering capability not negotiated");
                        parse_list_objects_filter(&filter_options, arg);
                        continue;
                }

                if (!skip_prefix(line, "want ", &arg) ||
                    parse_oid_hex(arg, &oid_buf, &features))
                        die("git upload-pack: protocol error, "
                            "expected to get object ID, not '%s'", line);

                if (parse_feature_request(features, "deepen-relative"))
                        deepen_relative = 1;
                if (parse_feature_request(features, "multi_ack_detailed"))
                        multi_ack = 2;
                else if (parse_feature_request(features, "multi_ack"))
                        multi_ack = 1;
                if (parse_feature_request(features, "no-done"))
                        no_done = 1;
                if (parse_feature_request(features, "thin-pack"))
                        use_thin_pack = 1;
                if (parse_feature_request(features, "ofs-delta"))
                        use_ofs_delta = 1;
                if (parse_feature_request(features, "side-band-64k"))
                        use_sideband = LARGE_PACKET_MAX;
                else if (parse_feature_request(features, "side-band"))
                        use_sideband = DEFAULT_PACKET_MAX;
                if (parse_feature_request(features, "no-progress"))
                        no_progress = 1;
                if (parse_feature_request(features, "include-tag"))
                        use_include_tag = 1;
                if (allow_filter && parse_feature_request(features, "filter"))
                        filter_capability_requested = 1;

                o = parse_object(the_repository, &oid_buf);
                if (!o) {
                        packet_write_fmt(1,
                                         "ERR upload-pack: not our ref %s",
                                         oid_to_hex(&oid_buf));
                        die("git upload-pack: not our ref %s",
                            oid_to_hex(&oid_buf));
                }
                if (!(o->flags & WANTED)) {
                        o->flags |= WANTED;
                        if (!((allow_unadvertised_object_request & ALLOW_ANY_SHA1) == ALLOW_ANY_SHA1
                              || is_our_ref(o)))
                                has_non_tip = 1;
                        add_object_array(o, NULL, &want_obj);
                }
        }

        /*
         * We have sent all our refs already, and the other end
         * should have chosen out of them. When we are operating
         * in the stateless RPC mode, however, their choice may
         * have been based on the set of older refs advertised
         * by another process that handled the initial request.
         */
        if (has_non_tip)
                check_non_tip();

        if (!use_sideband && daemon_mode)
                no_progress = 1;

        if (depth == 0 && !deepen_rev_list && shallows.nr == 0)
                return;

        if (send_shallow_list(depth, deepen_rev_list, deepen_since,
                              &deepen_not, &shallows))
                packet_flush(1);
        object_array_clear(&shallows);
}

/* return non-zero if the ref is hidden, otherwise 0 */
static int mark_our_ref(const char *refname, const char *refname_full,
                        const struct object_id *oid)
{
        struct object *o = lookup_unknown_object(oid->hash);

        if (ref_is_hidden(refname, refname_full)) {
                o->flags |= HIDDEN_REF;
                return 1;
        }
        o->flags |= OUR_REF;
        return 0;
}

static int check_ref(const char *refname_full, const struct object_id *oid,
                     int flag, void *cb_data)
{
        const char *refname = strip_namespace(refname_full);

        mark_our_ref(refname, refname_full, oid);
        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, " symref=%s:%s", item->string, (char *)item->util);
}

static int send_ref(const char *refname, const struct object_id *oid,
                    int flag, void *cb_data)
{
        static const char *capabilities = "multi_ack thin-pack side-band"
                " side-band-64k ofs-delta shallow deepen-since deepen-not"
                " deepen-relative no-progress include-tag multi_ack_detailed";
        const char *refname_nons = strip_namespace(refname);
        struct object_id peeled;

        if (mark_our_ref(refname_nons, refname, oid))
                return 0;

        if (capabilities) {
                struct strbuf symref_info = STRBUF_INIT;

                format_symref_info(&symref_info, cb_data);
                packet_write_fmt(1, "%s %s%c%s%s%s%s%s%s agent=%s\n",
                             oid_to_hex(oid), refname_nons,
                             0, capabilities,
                             (allow_unadvertised_object_request & ALLOW_TIP_SHA1) ?
                                     " allow-tip-sha1-in-want" : "",
                             (allow_unadvertised_object_request & ALLOW_REACHABLE_SHA1) ?
                                     " allow-reachable-sha1-in-want" : "",
                             stateless_rpc ? " no-done" : "",
                             symref_info.buf,
                             allow_filter ? " filter" : "",
                             git_user_agent_sanitized());
                strbuf_release(&symref_info);
        } else {
                packet_write_fmt(1, "%s %s\n", oid_to_hex(oid), refname_nons);
        }
        capabilities = NULL;
        if (!peel_ref(refname, &peeled))
                packet_write_fmt(1, "%s %s^{}\n", oid_to_hex(&peeled), refname_nons);
        return 0;
}

static int find_symref(const char *refname, const struct object_id *oid,
                       int flag, void *cb_data)
{
        const char *symref_target;
        struct string_list_item *item;

        if ((flag & REF_ISSYMREF) == 0)
                return 0;
        symref_target = resolve_ref_unsafe(refname, 0, NULL, &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 int upload_pack_config(const char *var, const char *value, void *unused)
{
        if (!strcmp("uploadpack.allowtipsha1inwant", var)) {
                if (git_config_bool(var, value))
                        allow_unadvertised_object_request |= ALLOW_TIP_SHA1;
                else
                        allow_unadvertised_object_request &= ~ALLOW_TIP_SHA1;
        } else if (!strcmp("uploadpack.allowreachablesha1inwant", var)) {
                if (git_config_bool(var, value))
                        allow_unadvertised_object_request |= ALLOW_REACHABLE_SHA1;
                else
                        allow_unadvertised_object_request &= ~ALLOW_REACHABLE_SHA1;
        } else if (!strcmp("uploadpack.allowanysha1inwant", var)) {
                if (git_config_bool(var, value))
                        allow_unadvertised_object_request |= ALLOW_ANY_SHA1;
                else
                        allow_unadvertised_object_request &= ~ALLOW_ANY_SHA1;
        } else if (!strcmp("uploadpack.keepalive", var)) {
                keepalive = git_config_int(var, value);
                if (!keepalive)
                        keepalive = -1;
        } else if (current_config_scope() != CONFIG_SCOPE_REPO) {
                if (!strcmp("uploadpack.packobjectshook", var))
                        return git_config_string(&pack_objects_hook, var, value);
        } else if (!strcmp("uploadpack.allowfilter", var)) {
                allow_filter = git_config_bool(var, value);
        }
        return parse_hide_refs_config(var, value, "uploadpack");
}

void upload_pack(struct upload_pack_options *options)
{
        struct string_list symref = STRING_LIST_INIT_DUP;

        stateless_rpc = options->stateless_rpc;
        timeout = options->timeout;
        daemon_mode = options->daemon_mode;

        git_config(upload_pack_config, NULL);

        head_ref_namespaced(find_symref, &symref);

        if (options->advertise_refs || !stateless_rpc) {
                reset_timeout();
                head_ref_namespaced(send_ref, &symref);
                for_each_namespaced_ref(send_ref, &symref);
                advertise_shallow_grafts(1);
                packet_flush(1);
        } else {
                head_ref_namespaced(check_ref, NULL);
                for_each_namespaced_ref(check_ref, NULL);
        }
        string_list_clear(&symref, 1);
        if (options->advertise_refs)
                return;

        receive_needs();
        if (want_obj.nr) {
                get_common_commits();
                create_pack_file();
        }
}

struct upload_pack_data {
        struct object_array wants;
        struct oid_array haves;

        struct object_array shallows;
        struct string_list deepen_not;
        int depth;
        timestamp_t deepen_since;
        int deepen_rev_list;
        int deepen_relative;

        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;
};

static void upload_pack_data_init(struct upload_pack_data *data)
{
        struct object_array wants = OBJECT_ARRAY_INIT;
        struct oid_array haves = OID_ARRAY_INIT;
        struct object_array shallows = OBJECT_ARRAY_INIT;
        struct string_list deepen_not = STRING_LIST_INIT_DUP;

        memset(data, 0, sizeof(*data));
        data->wants = wants;
        data->haves = haves;
        data->shallows = shallows;
        data->deepen_not = deepen_not;
}

static void upload_pack_data_clear(struct upload_pack_data *data)
{
        object_array_clear(&data->wants);
        oid_array_clear(&data->haves);
        object_array_clear(&data->shallows);
        string_list_clear(&data->deepen_not, 0);
}

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(the_repository, &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;
        }

        return 0;
}

static void process_args(struct packet_reader *request,
                         struct upload_pack_data *data)
{
        while (packet_reader_read(request) != PACKET_READ_FLUSH) {
                const char *arg = request->line;
                const char *p;

                /* 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;
                }

                /* Shallow related arguments */
                if (process_shallow(arg, &data->shallows))
                        continue;
                if (process_deepen(arg, &data->depth))
                        continue;
                if (process_deepen_since(arg, &data->deepen_since,
                                         &data->deepen_rev_list))
                        continue;
                if (process_deepen_not(arg, &data->deepen_not,
                                       &data->deepen_rev_list))
                        continue;
                if (!strcmp(arg, "deepen-relative")) {
                        data->deepen_relative = 1;
                        continue;
                }

                if (allow_filter && skip_prefix(arg, "filter ", &p)) {
                        parse_list_objects_filter(&filter_options, p);
                        continue;
                }

                /* ignore unknown lines maybe? */
                die("unexpected line: '%s'", arg);
        }
}

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(the_repository, 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;

        packet_buf_write(response, "acknowledgments\n");

        /* Send Acks */
        if (!acks->nr)
                packet_buf_write(response, "NAK\n");

        for (i = 0; i < acks->nr; i++) {
                packet_buf_write(response, "ACK %s\n",
                                 oid_to_hex(&acks->oid[i]));
        }

        if (ok_to_give_up()) {
                /* Send Ready */
                packet_buf_write(response, "ready\n");
                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;
}

static void send_shallow_info(struct upload_pack_data *data)
{
        /* No shallow info needs to be sent */
        if (!data->depth && !data->deepen_rev_list && !data->shallows.nr &&
            !is_repository_shallow(the_repository))
                return;

        packet_write_fmt(1, "shallow-info\n");

        if (!send_shallow_list(data->depth, data->deepen_rev_list,
                               data->deepen_since, &data->deepen_not,
                               &data->shallows) &&
            is_repository_shallow(the_repository))
                deepen(INFINITE_DEPTH, data->deepen_relative, &data->shallows);

        packet_delim(1);
}

enum fetch_state {
        FETCH_PROCESS_ARGS = 0,
        FETCH_SEND_ACKS,
        FETCH_SEND_PACK,
        FETCH_DONE,
};

int upload_pack_v2(struct repository *r, struct argv_array *keys,
                   struct packet_reader *request)
{
        enum fetch_state state = FETCH_PROCESS_ARGS;
        struct upload_pack_data data;

        git_config(upload_pack_config, NULL);

        upload_pack_data_init(&data);
        use_sideband = LARGE_PACKET_MAX;

        while (state != FETCH_DONE) {
                switch (state) {
                case FETCH_PROCESS_ARGS:
                        process_args(request, &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_SEND_ACKS:
                        if (process_haves_and_send_acks(&data))
                                state = FETCH_SEND_PACK;
                        else
                                state = FETCH_DONE;
                        break;
                case FETCH_SEND_PACK:
                        send_shallow_info(&data);

                        packet_write_fmt(1, "packfile\n");
                        create_pack_file();
                        state = FETCH_DONE;
                        break;
                case FETCH_DONE:
                        continue;
                }
        }

        upload_pack_data_clear(&data);
        return 0;
}

int upload_pack_advertise(struct repository *r,
                          struct strbuf *value)
{
        if (value) {
                int allow_filter_value;
                strbuf_addstr(value, "shallow");
                if (!repo_config_get_bool(the_repository,
                                         "uploadpack.allowfilter",
                                         &allow_filter_value) &&
                    allow_filter_value)
                        strbuf_addstr(value, " filter");
        }
        return 1;
}