#include "cache.h"
#include "transport.h"
#include "run-command.h"
#include "pkt-line.h"
#include "fetch-pack.h"
#include "remote.h"
#include "connect.h"
#include "send-pack.h"
#include "walker.h"
#include "bundle.h"
#include "dir.h"
#include "refs.h"
#include "branch.h"
#include "url.h"
#include "submodule.h"
#include "string-list.h"
#include "sha1-array.h"

/* rsync support */

/*
 * We copy packed-refs and refs/ into a temporary file, then read the
 * loose refs recursively (sorting whenever possible), and then inserting
 * those packed refs that are not yet in the list (not validating, but
 * assuming that the file is sorted).
 *
 * Appears refactoring this from refs.c is too cumbersome.
 */

static int str_cmp(const void *a, const void *b)
{
        const char *s1 = a;
        const char *s2 = b;

        return strcmp(s1, s2);
}

/* path->buf + name_offset is expected to point to "refs/" */

static int read_loose_refs(struct strbuf *path, int name_offset,
                struct ref **tail)
{
        DIR *dir = opendir(path->buf);
        struct dirent *de;
        struct {
                char **entries;
                int nr, alloc;
        } list;
        int i, pathlen;

        if (!dir)
                return -1;

        memset (&list, 0, sizeof(list));

        while ((de = readdir(dir))) {
                if (is_dot_or_dotdot(de->d_name))
                        continue;
                ALLOC_GROW(list.entries, list.nr + 1, list.alloc);
                list.entries[list.nr++] = xstrdup(de->d_name);
        }
        closedir(dir);

        /* sort the list */

        qsort(list.entries, list.nr, sizeof(char *), str_cmp);

        pathlen = path->len;
        strbuf_addch(path, '/');

        for (i = 0; i < list.nr; i++, strbuf_setlen(path, pathlen + 1)) {
                strbuf_addstr(path, list.entries[i]);
                if (read_loose_refs(path, name_offset, tail)) {
                        int fd = open(path->buf, O_RDONLY);
                        char buffer[40];
                        struct ref *next;

                        if (fd < 0)
                                continue;
                        next = alloc_ref(path->buf + name_offset);
                        if (read_in_full(fd, buffer, 40) != 40 ||
                                        get_sha1_hex(buffer, next->old_sha1)) {
                                close(fd);
                                free(next);
                                continue;
                        }
                        close(fd);
                        (*tail)->next = next;
                        *tail = next;
                }
        }
        strbuf_setlen(path, pathlen);

        for (i = 0; i < list.nr; i++)
                free(list.entries[i]);
        free(list.entries);

        return 0;
}

/* insert the packed refs for which no loose refs were found */

static void insert_packed_refs(const char *packed_refs, struct ref **list)
{
        FILE *f = fopen(packed_refs, "r");
        static char buffer[PATH_MAX];

        if (!f)
                return;

        for (;;) {
                int cmp = 0; /* assigned before used */
                int len;

                if (!fgets(buffer, sizeof(buffer), f)) {
                        fclose(f);
                        return;
                }

                if (!isxdigit(buffer[0]))
                        continue;
                len = strlen(buffer);
                if (len && buffer[len - 1] == '\n')
                        buffer[--len] = '\0';
                if (len < 41)
                        continue;
                while ((*list)->next &&
                                (cmp = strcmp(buffer + 41,
                                      (*list)->next->name)) > 0)
                        list = &(*list)->next;
                if (!(*list)->next || cmp < 0) {
                        struct ref *next = alloc_ref(buffer + 41);
                        buffer[40] = '\0';
                        if (get_sha1_hex(buffer, next->old_sha1)) {
                                warning ("invalid SHA-1: %s", buffer);
                                free(next);
                                continue;
                        }
                        next->next = (*list)->next;
                        (*list)->next = next;
                        list = &(*list)->next;
                }
        }
}

static void set_upstreams(struct transport *transport, struct ref *refs,
        int pretend)
{
        struct ref *ref;
        for (ref = refs; ref; ref = ref->next) {
                const char *localname;
                const char *tmp;
                const char *remotename;
                unsigned char sha[20];
                int flag = 0;
                /*
                 * Check suitability for tracking. Must be successful /
                 * already up-to-date ref create/modify (not delete).
                 */
                if (ref->status != REF_STATUS_OK &&
                        ref->status != REF_STATUS_UPTODATE)
                        continue;
                if (!ref->peer_ref)
                        continue;
                if (is_null_sha1(ref->new_sha1))
                        continue;

                /* Follow symbolic refs (mainly for HEAD). */
                localname = ref->peer_ref->name;
                remotename = ref->name;
                tmp = resolve_ref_unsafe(localname, RESOLVE_REF_READING,
                                         sha, &flag);
                if (tmp && flag & REF_ISSYMREF &&
                        starts_with(tmp, "refs/heads/"))
                        localname = tmp;

                /* Both source and destination must be local branches. */
                if (!localname || !starts_with(localname, "refs/heads/"))
                        continue;
                if (!remotename || !starts_with(remotename, "refs/heads/"))
                        continue;

                if (!pretend)
                        install_branch_config(BRANCH_CONFIG_VERBOSE,
                                localname + 11, transport->remote->name,
                                remotename);
                else
                        printf("Would set upstream of '%s' to '%s' of '%s'\n",
                                localname + 11, remotename + 11,
                                transport->remote->name);
        }
}

static const char *rsync_url(const char *url)
{
        if (!starts_with(url, "rsync://"))
                skip_prefix(url, "rsync:", &url);
        return url;
}

static struct ref *get_refs_via_rsync(struct transport *transport, int for_push)
{
        struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
        struct ref dummy = {NULL}, *tail = &dummy;
        struct child_process rsync = CHILD_PROCESS_INIT;
        const char *args[5];
        int temp_dir_len;

        if (for_push)
                return NULL;

        /* copy the refs to the temporary directory */

        strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
        if (!mkdtemp(temp_dir.buf))
                die_errno ("Could not make temporary directory");
        temp_dir_len = temp_dir.len;

        strbuf_addstr(&buf, rsync_url(transport->url));
        strbuf_addstr(&buf, "/refs");

        rsync.argv = args;
        rsync.stdout_to_stderr = 1;
        args[0] = "rsync";
        args[1] = (transport->verbose > 1) ? "-rv" : "-r";
        args[2] = buf.buf;
        args[3] = temp_dir.buf;
        args[4] = NULL;

        if (run_command(&rsync))
                die ("Could not run rsync to get refs");

        strbuf_reset(&buf);
        strbuf_addstr(&buf, rsync_url(transport->url));
        strbuf_addstr(&buf, "/packed-refs");

        args[2] = buf.buf;

        if (run_command(&rsync))
                die ("Could not run rsync to get refs");

        /* read the copied refs */

        strbuf_addstr(&temp_dir, "/refs");
        read_loose_refs(&temp_dir, temp_dir_len + 1, &tail);
        strbuf_setlen(&temp_dir, temp_dir_len);

        tail = &dummy;
        strbuf_addstr(&temp_dir, "/packed-refs");
        insert_packed_refs(temp_dir.buf, &tail);
        strbuf_setlen(&temp_dir, temp_dir_len);

        if (remove_dir_recursively(&temp_dir, 0))
                warning ("Error removing temporary directory %s.",
                                temp_dir.buf);

        strbuf_release(&buf);
        strbuf_release(&temp_dir);

        return dummy.next;
}

static int fetch_objs_via_rsync(struct transport *transport,
                                int nr_objs, struct ref **to_fetch)
{
        struct child_process rsync = CHILD_PROCESS_INIT;

        rsync.stdout_to_stderr = 1;
        argv_array_push(&rsync.args, "rsync");
        argv_array_push(&rsync.args, (transport->verbose > 1) ? "-rv" : "-r");
        argv_array_push(&rsync.args, "--ignore-existing");
        argv_array_push(&rsync.args, "--exclude");
        argv_array_push(&rsync.args, "info");
        argv_array_pushf(&rsync.args, "%s/objects/", rsync_url(transport->url));
        argv_array_push(&rsync.args, get_object_directory());

        /* NEEDSWORK: handle one level of alternates */
        return run_command(&rsync);
}

static int write_one_ref(const char *name, const struct object_id *oid,
                         int flags, void *data)
{
        struct strbuf *buf = data;
        int len = buf->len;

        /* when called via for_each_ref(), flags is non-zero */
        if (flags && !starts_with(name, "refs/heads/") &&
                        !starts_with(name, "refs/tags/"))
                return 0;

        strbuf_addstr(buf, name);
        if (safe_create_leading_directories(buf->buf) ||
            write_file(buf->buf, 0, "%s\n", oid_to_hex(oid)))
                return error("problems writing temporary file %s: %s",
                             buf->buf, strerror(errno));
        strbuf_setlen(buf, len);
        return 0;
}

static int write_refs_to_temp_dir(struct strbuf *temp_dir,
                                  int refspec_nr, const char **refspec)
{
        int i;

        for (i = 0; i < refspec_nr; i++) {
                struct object_id oid;
                char *ref;

                if (dwim_ref(refspec[i], strlen(refspec[i]), oid.hash, &ref) != 1)
                        return error("Could not get ref %s", refspec[i]);

                if (write_one_ref(ref, &oid, 0, temp_dir)) {
                        free(ref);
                        return -1;
                }
                free(ref);
        }
        return 0;
}

static int rsync_transport_push(struct transport *transport,
                int refspec_nr, const char **refspec, int flags)
{
        struct strbuf buf = STRBUF_INIT, temp_dir = STRBUF_INIT;
        int result = 0, i;
        struct child_process rsync = CHILD_PROCESS_INIT;
        const char *args[10];

        if (flags & TRANSPORT_PUSH_MIRROR)
                return error("rsync transport does not support mirror mode");

        /* first push the objects */

        strbuf_addstr(&buf, rsync_url(transport->url));
        strbuf_addch(&buf, '/');

        rsync.argv = args;
        rsync.stdout_to_stderr = 1;
        i = 0;
        args[i++] = "rsync";
        args[i++] = "-a";
        if (flags & TRANSPORT_PUSH_DRY_RUN)
                args[i++] = "--dry-run";
        if (transport->verbose > 1)
                args[i++] = "-v";
        args[i++] = "--ignore-existing";
        args[i++] = "--exclude";
        args[i++] = "info";
        args[i++] = get_object_directory();
        args[i++] = buf.buf;
        args[i++] = NULL;

        if (run_command(&rsync))
                return error("Could not push objects to %s",
                                rsync_url(transport->url));

        /* copy the refs to the temporary directory; they could be packed. */

        strbuf_addstr(&temp_dir, git_path("rsync-refs-XXXXXX"));
        if (!mkdtemp(temp_dir.buf))
                die_errno ("Could not make temporary directory");
        strbuf_addch(&temp_dir, '/');

        if (flags & TRANSPORT_PUSH_ALL) {
                if (for_each_ref(write_one_ref, &temp_dir))
                        return -1;
        } else if (write_refs_to_temp_dir(&temp_dir, refspec_nr, refspec))
                return -1;

        i = 2;
        if (flags & TRANSPORT_PUSH_DRY_RUN)
                args[i++] = "--dry-run";
        if (!(flags & TRANSPORT_PUSH_FORCE))
                args[i++] = "--ignore-existing";
        args[i++] = temp_dir.buf;
        args[i++] = rsync_url(transport->url);
        args[i++] = NULL;
        if (run_command(&rsync))
                result = error("Could not push to %s",
                                rsync_url(transport->url));

        if (remove_dir_recursively(&temp_dir, 0))
                warning ("Could not remove temporary directory %s.",
                                temp_dir.buf);

        strbuf_release(&buf);
        strbuf_release(&temp_dir);

        return result;
}

struct bundle_transport_data {
        int fd;
        struct bundle_header header;
};

static struct ref *get_refs_from_bundle(struct transport *transport, int for_push)
{
        struct bundle_transport_data *data = transport->data;
        struct ref *result = NULL;
        int i;

        if (for_push)
                return NULL;

        if (data->fd > 0)
                close(data->fd);
        data->fd = read_bundle_header(transport->url, &data->header);
        if (data->fd < 0)
                die ("Could not read bundle '%s'.", transport->url);
        for (i = 0; i < data->header.references.nr; i++) {
                struct ref_list_entry *e = data->header.references.list + i;
                struct ref *ref = alloc_ref(e->name);
                hashcpy(ref->old_sha1, e->sha1);
                ref->next = result;
                result = ref;
        }
        return result;
}

static int fetch_refs_from_bundle(struct transport *transport,
                               int nr_heads, struct ref **to_fetch)
{
        struct bundle_transport_data *data = transport->data;
        return unbundle(&data->header, data->fd,
                        transport->progress ? BUNDLE_VERBOSE : 0);
}

static int close_bundle(struct transport *transport)
{
        struct bundle_transport_data *data = transport->data;
        if (data->fd > 0)
                close(data->fd);
        free(data);
        return 0;
}

struct git_transport_data {
        struct git_transport_options options;
        struct child_process *conn;
        int fd[2];
        unsigned got_remote_heads : 1;
        struct sha1_array extra_have;
        struct sha1_array shallow;
};

static int set_git_option(struct git_transport_options *opts,
                          const char *name, const char *value)
{
        if (!strcmp(name, TRANS_OPT_UPLOADPACK)) {
                opts->uploadpack = value;
                return 0;
        } else if (!strcmp(name, TRANS_OPT_RECEIVEPACK)) {
                opts->receivepack = value;
                return 0;
        } else if (!strcmp(name, TRANS_OPT_THIN)) {
                opts->thin = !!value;
                return 0;
        } else if (!strcmp(name, TRANS_OPT_FOLLOWTAGS)) {
                opts->followtags = !!value;
                return 0;
        } else if (!strcmp(name, TRANS_OPT_KEEP)) {
                opts->keep = !!value;
                return 0;
        } else if (!strcmp(name, TRANS_OPT_UPDATE_SHALLOW)) {
                opts->update_shallow = !!value;
                return 0;
        } else if (!strcmp(name, TRANS_OPT_DEPTH)) {
                if (!value)
                        opts->depth = 0;
                else {
                        char *end;
                        opts->depth = strtol(value, &end, 0);
                        if (*end)
                                die("transport: invalid depth option '%s'", value);
                }
                return 0;
        } else if (!strcmp(name, TRANS_OPT_PUSH_CERT)) {
                opts->push_cert = !!value;
                return 0;
        }
        return 1;
}

static int connect_setup(struct transport *transport, int for_push, int verbose)
{
        struct git_transport_data *data = transport->data;

        if (data->conn)
                return 0;

        data->conn = git_connect(data->fd, transport->url,
                                 for_push ? data->options.receivepack :
                                 data->options.uploadpack,
                                 verbose ? CONNECT_VERBOSE : 0);

        return 0;
}

static struct ref *get_refs_via_connect(struct transport *transport, int for_push)
{
        struct git_transport_data *data = transport->data;
        struct ref *refs;

        connect_setup(transport, for_push, 0);
        get_remote_heads(data->fd[0], NULL, 0, &refs,
                         for_push ? REF_NORMAL : 0,
                         &data->extra_have,
                         &data->shallow);
        data->got_remote_heads = 1;

        return refs;
}

static int fetch_refs_via_pack(struct transport *transport,
                               int nr_heads, struct ref **to_fetch)
{
        struct git_transport_data *data = transport->data;
        struct ref *refs;
        char *dest = xstrdup(transport->url);
        struct fetch_pack_args args;
        struct ref *refs_tmp = NULL;

        memset(&args, 0, sizeof(args));
        args.uploadpack = data->options.uploadpack;
        args.keep_pack = data->options.keep;
        args.lock_pack = 1;
        args.use_thin_pack = data->options.thin;
        args.include_tag = data->options.followtags;
        args.verbose = (transport->verbose > 1);
        args.quiet = (transport->verbose < 0);
        args.no_progress = !transport->progress;
        args.depth = data->options.depth;
        args.check_self_contained_and_connected =
                data->options.check_self_contained_and_connected;
        args.cloning = transport->cloning;
        args.update_shallow = data->options.update_shallow;

        if (!data->got_remote_heads) {
                connect_setup(transport, 0, 0);
                get_remote_heads(data->fd[0], NULL, 0, &refs_tmp, 0,
                                 NULL, &data->shallow);
                data->got_remote_heads = 1;
        }

        refs = fetch_pack(&args, data->fd, data->conn,
                          refs_tmp ? refs_tmp : transport->remote_refs,
                          dest, to_fetch, nr_heads, &data->shallow,
                          &transport->pack_lockfile);
        close(data->fd[0]);
        close(data->fd[1]);
        if (finish_connect(data->conn)) {
                free_refs(refs);
                refs = NULL;
        }
        data->conn = NULL;
        data->got_remote_heads = 0;
        data->options.self_contained_and_connected =
                args.self_contained_and_connected;

        free_refs(refs_tmp);
        free_refs(refs);
        free(dest);
        return (refs ? 0 : -1);
}

static int push_had_errors(struct ref *ref)
{
        for (; ref; ref = ref->next) {
                switch (ref->status) {
                case REF_STATUS_NONE:
                case REF_STATUS_UPTODATE:
                case REF_STATUS_OK:
                        break;
                default:
                        return 1;
                }
        }
        return 0;
}

int transport_refs_pushed(struct ref *ref)
{
        for (; ref; ref = ref->next) {
                switch(ref->status) {
                case REF_STATUS_NONE:
                case REF_STATUS_UPTODATE:
                        break;
                default:
                        return 1;
                }
        }
        return 0;
}

void transport_update_tracking_ref(struct remote *remote, struct ref *ref, int verbose)
{
        struct refspec rs;

        if (ref->status != REF_STATUS_OK && ref->status != REF_STATUS_UPTODATE)
                return;

        rs.src = ref->name;
        rs.dst = NULL;

        if (!remote_find_tracking(remote, &rs)) {
                if (verbose)
                        fprintf(stderr, "updating local tracking ref '%s'\n", rs.dst);
                if (ref->deletion) {
                        delete_ref(rs.dst, NULL, 0);
                } else
                        update_ref("update by push", rs.dst,
                                        ref->new_sha1, NULL, 0, 0);
                free(rs.dst);
        }
}

static void print_ref_status(char flag, const char *summary, struct ref *to, struct ref *from, const char *msg, int porcelain)
{
        if (porcelain) {
                if (from)
                        fprintf(stdout, "%c\t%s:%s\t", flag, from->name, to->name);
                else
                        fprintf(stdout, "%c\t:%s\t", flag, to->name);
                if (msg)
                        fprintf(stdout, "%s (%s)\n", summary, msg);
                else
                        fprintf(stdout, "%s\n", summary);
        } else {
                fprintf(stderr, " %c %-*s ", flag, TRANSPORT_SUMMARY_WIDTH, summary);
                if (from)
                        fprintf(stderr, "%s -> %s", prettify_refname(from->name), prettify_refname(to->name));
                else
                        fputs(prettify_refname(to->name), stderr);
                if (msg) {
                        fputs(" (", stderr);
                        fputs(msg, stderr);
                        fputc(')', stderr);
                }
                fputc('\n', stderr);
        }
}

static const char *status_abbrev(unsigned char sha1[20])
{
        return find_unique_abbrev(sha1, DEFAULT_ABBREV);
}

static void print_ok_ref_status(struct ref *ref, int porcelain)
{
        if (ref->deletion)
                print_ref_status('-', "[deleted]", ref, NULL, NULL, porcelain);
        else if (is_null_sha1(ref->old_sha1))
                print_ref_status('*',
                        (starts_with(ref->name, "refs/tags/") ? "[new tag]" :
                        "[new branch]"),
                        ref, ref->peer_ref, NULL, porcelain);
        else {
                char quickref[84];
                char type;
                const char *msg;

                strcpy(quickref, status_abbrev(ref->old_sha1));
                if (ref->forced_update) {
                        strcat(quickref, "...");
                        type = '+';
                        msg = "forced update";
                } else {
                        strcat(quickref, "..");
                        type = ' ';
                        msg = NULL;
                }
                strcat(quickref, status_abbrev(ref->new_sha1));

                print_ref_status(type, quickref, ref, ref->peer_ref, msg, porcelain);
        }
}

static int print_one_push_status(struct ref *ref, const char *dest, int count, int porcelain)
{
        if (!count)
                fprintf(porcelain ? stdout : stderr, "To %s\n", dest);

        switch(ref->status) {
        case REF_STATUS_NONE:
                print_ref_status('X', "[no match]", ref, NULL, NULL, porcelain);
                break;
        case REF_STATUS_REJECT_NODELETE:
                print_ref_status('!', "[rejected]", ref, NULL,
                                                 "remote does not support deleting refs", porcelain);
                break;
        case REF_STATUS_UPTODATE:
                print_ref_status('=', "[up to date]", ref,
                                                 ref->peer_ref, NULL, porcelain);
                break;
        case REF_STATUS_REJECT_NONFASTFORWARD:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "non-fast-forward", porcelain);
                break;
        case REF_STATUS_REJECT_ALREADY_EXISTS:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "already exists", porcelain);
                break;
        case REF_STATUS_REJECT_FETCH_FIRST:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "fetch first", porcelain);
                break;
        case REF_STATUS_REJECT_NEEDS_FORCE:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "needs force", porcelain);
                break;
        case REF_STATUS_REJECT_STALE:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "stale info", porcelain);
                break;
        case REF_STATUS_REJECT_SHALLOW:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "new shallow roots not allowed", porcelain);
                break;
        case REF_STATUS_REMOTE_REJECT:
                print_ref_status('!', "[remote rejected]", ref,
                                                 ref->deletion ? NULL : ref->peer_ref,
                                                 ref->remote_status, porcelain);
                break;
        case REF_STATUS_EXPECTING_REPORT:
                print_ref_status('!', "[remote failure]", ref,
                                                 ref->deletion ? NULL : ref->peer_ref,
                                                 "remote failed to report status", porcelain);
                break;
        case REF_STATUS_ATOMIC_PUSH_FAILED:
                print_ref_status('!', "[rejected]", ref, ref->peer_ref,
                                                 "atomic push failed", porcelain);
                break;
        case REF_STATUS_OK:
                print_ok_ref_status(ref, porcelain);
                break;
        }

        return 1;
}

void transport_print_push_status(const char *dest, struct ref *refs,
                                  int verbose, int porcelain, unsigned int *reject_reasons)
{
        struct ref *ref;
        int n = 0;
        unsigned char head_sha1[20];
        char *head;

        head = resolve_refdup("HEAD", RESOLVE_REF_READING, head_sha1, NULL);

        if (verbose) {
                for (ref = refs; ref; ref = ref->next)
                        if (ref->status == REF_STATUS_UPTODATE)
                                n += print_one_push_status(ref, dest, n, porcelain);
        }

        for (ref = refs; ref; ref = ref->next)
                if (ref->status == REF_STATUS_OK)
                        n += print_one_push_status(ref, dest, n, porcelain);

        *reject_reasons = 0;
        for (ref = refs; ref; ref = ref->next) {
                if (ref->status != REF_STATUS_NONE &&
                    ref->status != REF_STATUS_UPTODATE &&
                    ref->status != REF_STATUS_OK)
                        n += print_one_push_status(ref, dest, n, porcelain);
                if (ref->status == REF_STATUS_REJECT_NONFASTFORWARD) {
                        if (head != NULL && !strcmp(head, ref->name))
                                *reject_reasons |= REJECT_NON_FF_HEAD;
                        else
                                *reject_reasons |= REJECT_NON_FF_OTHER;
                } else if (ref->status == REF_STATUS_REJECT_ALREADY_EXISTS) {
                        *reject_reasons |= REJECT_ALREADY_EXISTS;
                } else if (ref->status == REF_STATUS_REJECT_FETCH_FIRST) {
                        *reject_reasons |= REJECT_FETCH_FIRST;
                } else if (ref->status == REF_STATUS_REJECT_NEEDS_FORCE) {
                        *reject_reasons |= REJECT_NEEDS_FORCE;
                }
        }
        free(head);
}

void transport_verify_remote_names(int nr_heads, const char **heads)
{
        int i;

        for (i = 0; i < nr_heads; i++) {
                const char *local = heads[i];
                const char *remote = strrchr(heads[i], ':');

                if (*local == '+')
                        local++;

                /* A matching refspec is okay.  */
                if (remote == local && remote[1] == '\0')
                        continue;

                remote = remote ? (remote + 1) : local;
                if (check_refname_format(remote,
                                REFNAME_ALLOW_ONELEVEL|REFNAME_REFSPEC_PATTERN))
                        die("remote part of refspec is not a valid name in %s",
                                heads[i]);
        }
}

static int git_transport_push(struct transport *transport, struct ref *remote_refs, int flags)
{
        struct git_transport_data *data = transport->data;
        struct send_pack_args args;
        int ret;

        if (!data->got_remote_heads) {
                struct ref *tmp_refs;
                connect_setup(transport, 1, 0);

                get_remote_heads(data->fd[0], NULL, 0, &tmp_refs, REF_NORMAL,
                                 NULL, &data->shallow);
                data->got_remote_heads = 1;
        }

        memset(&args, 0, sizeof(args));
        args.send_mirror = !!(flags & TRANSPORT_PUSH_MIRROR);
        args.force_update = !!(flags & TRANSPORT_PUSH_FORCE);
        args.use_thin_pack = data->options.thin;
        args.verbose = (transport->verbose > 0);
        args.quiet = (transport->verbose < 0);
        args.progress = transport->progress;
        args.dry_run = !!(flags & TRANSPORT_PUSH_DRY_RUN);
        args.porcelain = !!(flags & TRANSPORT_PUSH_PORCELAIN);
        args.push_cert = !!(flags & TRANSPORT_PUSH_CERT);
        args.atomic = !!(flags & TRANSPORT_PUSH_ATOMIC);
        args.url = transport->url;

        ret = send_pack(&args, data->fd, data->conn, remote_refs,
                        &data->extra_have);

        close(data->fd[1]);
        close(data->fd[0]);
        ret |= finish_connect(data->conn);
        data->conn = NULL;
        data->got_remote_heads = 0;

        return ret;
}

static int connect_git(struct transport *transport, const char *name,
                       const char *executable, int fd[2])
{
        struct git_transport_data *data = transport->data;
        data->conn = git_connect(data->fd, transport->url,
                                 executable, 0);
        fd[0] = data->fd[0];
        fd[1] = data->fd[1];
        return 0;
}

static int disconnect_git(struct transport *transport)
{
        struct git_transport_data *data = transport->data;
        if (data->conn) {
                if (data->got_remote_heads)
                        packet_flush(data->fd[1]);
                close(data->fd[0]);
                close(data->fd[1]);
                finish_connect(data->conn);
        }

        free(data);
        return 0;
}

void transport_take_over(struct transport *transport,
                         struct child_process *child)
{
        struct git_transport_data *data;

        if (!transport->smart_options)
                die("Bug detected: Taking over transport requires non-NULL "
                    "smart_options field.");

        data = xcalloc(1, sizeof(*data));
        data->options = *transport->smart_options;
        data->conn = child;
        data->fd[0] = data->conn->out;
        data->fd[1] = data->conn->in;
        data->got_remote_heads = 0;
        transport->data = data;

        transport->set_option = NULL;
        transport->get_refs_list = get_refs_via_connect;
        transport->fetch = fetch_refs_via_pack;
        transport->push = NULL;
        transport->push_refs = git_transport_push;
        transport->disconnect = disconnect_git;
        transport->smart_options = &(data->options);

        transport->cannot_reuse = 1;
}

static int is_file(const char *url)
{
        struct stat buf;
        if (stat(url, &buf))
                return 0;
        return S_ISREG(buf.st_mode);
}

static int external_specification_len(const char *url)
{
        return strchr(url, ':') - url;
}

struct transport *transport_get(struct remote *remote, const char *url)
{
        const char *helper;
        struct transport *ret = xcalloc(1, sizeof(*ret));

        ret->progress = isatty(2);

        if (!remote)
                die("No remote provided to transport_get()");

        ret->got_remote_refs = 0;
        ret->remote = remote;
        helper = remote->foreign_vcs;

        if (!url && remote->url)
                url = remote->url[0];
        ret->url = url;

        /* maybe it is a foreign URL? */
        if (url) {
                const char *p = url;

                while (is_urlschemechar(p == url, *p))
                        p++;
                if (starts_with(p, "::"))
                        helper = xstrndup(url, p - url);
        }

        if (helper) {
                transport_helper_init(ret, helper);
        } else if (starts_with(url, "rsync:")) {
                ret->get_refs_list = get_refs_via_rsync;
                ret->fetch = fetch_objs_via_rsync;
                ret->push = rsync_transport_push;
                ret->smart_options = NULL;
        } else if (url_is_local_not_ssh(url) && is_file(url) && is_bundle(url, 1)) {
                struct bundle_transport_data *data = xcalloc(1, sizeof(*data));
                ret->data = data;
                ret->get_refs_list = get_refs_from_bundle;
                ret->fetch = fetch_refs_from_bundle;
                ret->disconnect = close_bundle;
                ret->smart_options = NULL;
        } else if (!is_url(url)
                || starts_with(url, "file://")
                || starts_with(url, "git://")
                || starts_with(url, "ssh://")
                || starts_with(url, "git+ssh://")
                || starts_with(url, "ssh+git://")) {
                /* These are builtin smart transports. */
                struct git_transport_data *data = xcalloc(1, sizeof(*data));
                ret->data = data;
                ret->set_option = NULL;
                ret->get_refs_list = get_refs_via_connect;
                ret->fetch = fetch_refs_via_pack;
                ret->push_refs = git_transport_push;
                ret->connect = connect_git;
                ret->disconnect = disconnect_git;
                ret->smart_options = &(data->options);

                data->conn = NULL;
                data->got_remote_heads = 0;
        } else {
                /* Unknown protocol in URL. Pass to external handler. */
                int len = external_specification_len(url);
                char *handler = xmemdupz(url, len);
                transport_helper_init(ret, handler);
        }

        if (ret->smart_options) {
                ret->smart_options->thin = 1;
                ret->smart_options->uploadpack = "git-upload-pack";
                if (remote->uploadpack)
                        ret->smart_options->uploadpack = remote->uploadpack;
                ret->smart_options->receivepack = "git-receive-pack";
                if (remote->receivepack)
                        ret->smart_options->receivepack = remote->receivepack;
        }

        return ret;
}

int transport_set_option(struct transport *transport,
                         const char *name, const char *value)
{
        int git_reports = 1, protocol_reports = 1;

        if (transport->smart_options)
                git_reports = set_git_option(transport->smart_options,
                                             name, value);

        if (transport->set_option)
                protocol_reports = transport->set_option(transport, name,
                                                        value);

        /* If either report is 0, report 0 (success). */
        if (!git_reports || !protocol_reports)
                return 0;
        /* If either reports -1 (invalid value), report -1. */
        if ((git_reports == -1) || (protocol_reports == -1))
                return -1;
        /* Otherwise if both report unknown, report unknown. */
        return 1;
}

void transport_set_verbosity(struct transport *transport, int verbosity,
        int force_progress)
{
        if (verbosity >= 1)
                transport->verbose = verbosity <= 3 ? verbosity : 3;
        if (verbosity < 0)
                transport->verbose = -1;

        /**
         * Rules used to determine whether to report progress (processing aborts
         * when a rule is satisfied):
         *
         *   . Report progress, if force_progress is 1 (ie. --progress).
         *   . Don't report progress, if force_progress is 0 (ie. --no-progress).
         *   . Don't report progress, if verbosity < 0 (ie. -q/--quiet ).
         *   . Report progress if isatty(2) is 1.
         **/
        if (force_progress >= 0)
                transport->progress = !!force_progress;
        else
                transport->progress = verbosity >= 0 && isatty(2);
}

static void die_with_unpushed_submodules(struct string_list *needs_pushing)
{
        int i;

        fprintf(stderr, "The following submodule paths contain changes that can\n"
                        "not be found on any remote:\n");
        for (i = 0; i < needs_pushing->nr; i++)
                printf("  %s\n", needs_pushing->items[i].string);
        fprintf(stderr, "\nPlease try\n\n"
                        "       git push --recurse-submodules=on-demand\n\n"
                        "or cd to the path and use\n\n"
                        "       git push\n\n"
                        "to push them to a remote.\n\n");

        string_list_clear(needs_pushing, 0);

        die("Aborting.");
}

static int run_pre_push_hook(struct transport *transport,
                             struct ref *remote_refs)
{
        int ret = 0, x;
        struct ref *r;
        struct child_process proc = CHILD_PROCESS_INIT;
        struct strbuf buf;
        const char *argv[4];

        if (!(argv[0] = find_hook("pre-push")))
                return 0;

        argv[1] = transport->remote->name;
        argv[2] = transport->url;
        argv[3] = NULL;

        proc.argv = argv;
        proc.in = -1;

        if (start_command(&proc)) {
                finish_command(&proc);
                return -1;
        }

        strbuf_init(&buf, 256);

        for (r = remote_refs; r; r = r->next) {
                if (!r->peer_ref) continue;
                if (r->status == REF_STATUS_REJECT_NONFASTFORWARD) continue;
                if (r->status == REF_STATUS_REJECT_STALE) continue;
                if (r->status == REF_STATUS_UPTODATE) continue;

                strbuf_reset(&buf);
                strbuf_addf( &buf, "%s %s %s %s\n",
                         r->peer_ref->name, sha1_to_hex(r->new_sha1),
                         r->name, sha1_to_hex(r->old_sha1));

                if (write_in_full(proc.in, buf.buf, buf.len) != buf.len) {
                        ret = -1;
                        break;
                }
        }

        strbuf_release(&buf);

        x = close(proc.in);
        if (!ret)
                ret = x;

        x = finish_command(&proc);
        if (!ret)
                ret = x;

        return ret;
}

int transport_push(struct transport *transport,
                   int refspec_nr, const char **refspec, int flags,
                   unsigned int *reject_reasons)
{
        *reject_reasons = 0;
        transport_verify_remote_names(refspec_nr, refspec);

        if (transport->push) {
                /* Maybe FIXME. But no important transport uses this case. */
                if (flags & TRANSPORT_PUSH_SET_UPSTREAM)
                        die("This transport does not support using --set-upstream");

                return transport->push(transport, refspec_nr, refspec, flags);
        } else if (transport->push_refs) {
                struct ref *remote_refs;
                struct ref *local_refs = get_local_heads();
                int match_flags = MATCH_REFS_NONE;
                int verbose = (transport->verbose > 0);
                int quiet = (transport->verbose < 0);
                int porcelain = flags & TRANSPORT_PUSH_PORCELAIN;
                int pretend = flags & TRANSPORT_PUSH_DRY_RUN;
                int push_ret, ret, err;

                if (check_push_refs(local_refs, refspec_nr, refspec) < 0)
                        return -1;

                remote_refs = transport->get_refs_list(transport, 1);

                if (flags & TRANSPORT_PUSH_ALL)
                        match_flags |= MATCH_REFS_ALL;
                if (flags & TRANSPORT_PUSH_MIRROR)
                        match_flags |= MATCH_REFS_MIRROR;
                if (flags & TRANSPORT_PUSH_PRUNE)
                        match_flags |= MATCH_REFS_PRUNE;
                if (flags & TRANSPORT_PUSH_FOLLOW_TAGS)
                        match_flags |= MATCH_REFS_FOLLOW_TAGS;

                if (match_push_refs(local_refs, &remote_refs,
                                    refspec_nr, refspec, match_flags)) {
                        return -1;
                }

                if (transport->smart_options &&
                    transport->smart_options->cas &&
                    !is_empty_cas(transport->smart_options->cas))
                        apply_push_cas(transport->smart_options->cas,
                                       transport->remote, remote_refs);

                set_ref_status_for_push(remote_refs,
                        flags & TRANSPORT_PUSH_MIRROR,
                        flags & TRANSPORT_PUSH_FORCE);

                if (!(flags & TRANSPORT_PUSH_NO_HOOK))
                        if (run_pre_push_hook(transport, remote_refs))
                                return -1;

                if ((flags & TRANSPORT_RECURSE_SUBMODULES_ON_DEMAND) && !is_bare_repository()) {
                        struct ref *ref = remote_refs;
                        for (; ref; ref = ref->next)
                                if (!is_null_sha1(ref->new_sha1) &&
                                    !push_unpushed_submodules(ref->new_sha1,
                                            transport->remote->name))
                                    die ("Failed to push all needed submodules!");
                }

                if ((flags & (TRANSPORT_RECURSE_SUBMODULES_ON_DEMAND |
                              TRANSPORT_RECURSE_SUBMODULES_CHECK)) && !is_bare_repository()) {
                        struct ref *ref = remote_refs;
                        struct string_list needs_pushing = STRING_LIST_INIT_DUP;

                        for (; ref; ref = ref->next)
                                if (!is_null_sha1(ref->new_sha1) &&
                                    find_unpushed_submodules(ref->new_sha1,
                                            transport->remote->name, &needs_pushing))
                                        die_with_unpushed_submodules(&needs_pushing);
                }

                push_ret = transport->push_refs(transport, remote_refs, flags);
                err = push_had_errors(remote_refs);
                ret = push_ret | err;

                if (!quiet || err)
                        transport_print_push_status(transport->url, remote_refs,
                                        verbose | porcelain, porcelain,
                                        reject_reasons);

                if (flags & TRANSPORT_PUSH_SET_UPSTREAM)
                        set_upstreams(transport, remote_refs, pretend);

                if (!(flags & TRANSPORT_PUSH_DRY_RUN)) {
                        struct ref *ref;
                        for (ref = remote_refs; ref; ref = ref->next)
                                transport_update_tracking_ref(transport->remote, ref, verbose);
                }

                if (porcelain && !push_ret)
                        puts("Done");
                else if (!quiet && !ret && !transport_refs_pushed(remote_refs))
                        fprintf(stderr, "Everything up-to-date\n");

                return ret;
        }
        return 1;
}

const struct ref *transport_get_remote_refs(struct transport *transport)
{
        if (!transport->got_remote_refs) {
                transport->remote_refs = transport->get_refs_list(transport, 0);
                transport->got_remote_refs = 1;
        }

        return transport->remote_refs;
}

int transport_fetch_refs(struct transport *transport, struct ref *refs)
{
        int rc;
        int nr_heads = 0, nr_alloc = 0, nr_refs = 0;
        struct ref **heads = NULL;
        struct ref *rm;

        for (rm = refs; rm; rm = rm->next) {
                nr_refs++;
                if (rm->peer_ref &&
                    !is_null_sha1(rm->old_sha1) &&
                    !hashcmp(rm->peer_ref->old_sha1, rm->old_sha1))
                        continue;
                ALLOC_GROW(heads, nr_heads + 1, nr_alloc);
                heads[nr_heads++] = rm;
        }

        if (!nr_heads) {
                /*
                 * When deepening of a shallow repository is requested,
                 * then local and remote refs are likely to still be equal.
                 * Just feed them all to the fetch method in that case.
                 * This condition shouldn't be met in a non-deepening fetch
                 * (see builtin/fetch.c:quickfetch()).
                 */
                heads = xmalloc(nr_refs * sizeof(*heads));
                for (rm = refs; rm; rm = rm->next)
                        heads[nr_heads++] = rm;
        }

        rc = transport->fetch(transport, nr_heads, heads);

        free(heads);
        return rc;
}

void transport_unlock_pack(struct transport *transport)
{
        if (transport->pack_lockfile) {
                unlink_or_warn(transport->pack_lockfile);
                free(transport->pack_lockfile);
                transport->pack_lockfile = NULL;
        }
}

int transport_connect(struct transport *transport, const char *name,
                      const char *exec, int fd[2])
{
        if (transport->connect)
                return transport->connect(transport, name, exec, fd);
        else
                die("Operation not supported by protocol");
}

int transport_disconnect(struct transport *transport)
{
        int ret = 0;
        if (transport->disconnect)
                ret = transport->disconnect(transport);
        free(transport);
        return ret;
}

/*
 * Strip username (and password) from a URL and return
 * it in a newly allocated string.
 */
char *transport_anonymize_url(const char *url)
{
        char *anon_url, *scheme_prefix, *anon_part;
        size_t anon_len, prefix_len = 0;

        anon_part = strchr(url, '@');
        if (url_is_local_not_ssh(url) || !anon_part)
                goto literal_copy;

        anon_len = strlen(++anon_part);
        scheme_prefix = strstr(url, "://");
        if (!scheme_prefix) {
                if (!strchr(anon_part, ':'))
                        /* cannot be "me@there:/path/name" */
                        goto literal_copy;
        } else {
                const char *cp;
                /* make sure scheme is reasonable */
                for (cp = url; cp < scheme_prefix; cp++) {
                        switch (*cp) {
                                /* RFC 1738 2.1 */
                        case '+': case '.': case '-':
                                break; /* ok */
                        default:
                                if (isalnum(*cp))
                                        break;
                                /* it isn't */
                                goto literal_copy;
                        }
                }
                /* @ past the first slash does not count */
                cp = strchr(scheme_prefix + 3, '/');
                if (cp && cp < anon_part)
                        goto literal_copy;
                prefix_len = scheme_prefix - url + 3;
        }
        anon_url = xcalloc(1, 1 + prefix_len + anon_len);
        memcpy(anon_url, url, prefix_len);
        memcpy(anon_url + prefix_len, anon_part, anon_len);
        return anon_url;
literal_copy:
        return xstrdup(url);
}

struct alternate_refs_data {
        alternate_ref_fn *fn;
        void *data;
};

static int refs_from_alternate_cb(struct alternate_object_database *e,
                                  void *data)
{
        char *other;
        size_t len;
        struct remote *remote;
        struct transport *transport;
        const struct ref *extra;
        struct alternate_refs_data *cb = data;

        e->name[-1] = '\0';
        other = xstrdup(real_path(e->base));
        e->name[-1] = '/';
        len = strlen(other);

        while (other[len-1] == '/')
                other[--len] = '\0';
        if (len < 8 || memcmp(other + len - 8, "/objects", 8))
                goto out;
        /* Is this a git repository with refs? */
        memcpy(other + len - 8, "/refs", 6);
        if (!is_directory(other))
                goto out;
        other[len - 8] = '\0';
        remote = remote_get(other);
        transport = transport_get(remote, other);
        for (extra = transport_get_remote_refs(transport);
             extra;
             extra = extra->next)
                cb->fn(extra, cb->data);
        transport_disconnect(transport);
out:
        free(other);
        return 0;
}

void for_each_alternate_ref(alternate_ref_fn fn, void *data)
{
        struct alternate_refs_data cb;
        cb.fn = fn;
        cb.data = data;
        foreach_alt_odb(refs_from_alternate_cb, &cb);
}