#include "cache.h"
#include "refs.h"
#include "pkt-line.h"
#include "sideband.h"
#include "tag.h"
#include "object.h"
#include "commit.h"
#include "exec_cmd.h"
#include "diff.h"
#include "revision.h"
#include "list-objects.h"
#include "run-command.h"
#include "sigchain.h"
#include "version.h"
#include "string-list.h"

static const char upload_pack_usage[] = "git upload-pack [--strict] [--timeout=<n>] <dir>";

/* bits #0..7 in revision.h, #8..10 in commit.c */
#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 unsigned long oldest_have;

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;
static int allow_tip_sha1_in_want;
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 advertise_refs;
static int stateless_rpc;

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

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

static void create_pack_file(void)
{
        struct child_process pack_objects;
        char data[8193], progress[128];
        char abort_msg[] = "aborting due to possible repository "
                "corruption on the remote side.";
        int buffered = -1;
        ssize_t sz;
        const char *argv[12];
        int i, arg = 0;
        FILE *pipe_fd;
        char *shallow_file = NULL;

        if (shallow_nr) {
                shallow_file = setup_temporary_shallow();
                argv[arg++] = "--shallow-file";
                argv[arg++] = shallow_file;
        }
        argv[arg++] = "pack-objects";
        argv[arg++] = "--revs";
        if (use_thin_pack)
                argv[arg++] = "--thin";

        argv[arg++] = "--stdout";
        if (!no_progress)
                argv[arg++] = "--progress";
        if (use_ofs_delta)
                argv[arg++] = "--delta-base-offset";
        if (use_include_tag)
                argv[arg++] = "--include-tag";
        argv[arg++] = NULL;

        memset(&pack_objects, 0, sizeof(pack_objects));
        pack_objects.in = -1;
        pack_objects.out = -1;
        pack_objects.err = -1;
        pack_objects.git_cmd = 1;
        pack_objects.argv = argv;

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

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

        for (i = 0; i < want_obj.nr; i++)
                fprintf(pipe_fd, "%s\n",
                        sha1_to_hex(want_obj.objects[i].item->sha1));
        fprintf(pipe_fd, "--not\n");
        for (i = 0; i < have_obj.nr; i++)
                fprintf(pipe_fd, "%s\n",
                        sha1_to_hex(have_obj.objects[i].item->sha1));
        for (i = 0; i < extra_edge_obj.nr; i++)
                fprintf(pipe_fd, "%s\n",
                        sha1_to_hex(extra_edge_obj.objects[i].item->sha1));
        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, 1000 * keepalive);
                if (ret < 0) {
                        if (errno != EINTR) {
                                error("poll failed, resuming: %s",
                                      strerror(errno));
                                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;
                        sz = send_client_data(1, data, sz);
                        if (sz < 0)
                                goto fail;
                }

                /*
                 * 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;
        }
        if (shallow_file) {
                if (*shallow_file)
                        unlink(shallow_file);
                free(shallow_file);
        }

        /* flush the data */
        if (0 <= buffered) {
                data[0] = buffered;
                sz = send_client_data(1, data, 1);
                if (sz < 0)
                        goto fail;
                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_sha1(char *hex, unsigned char *sha1)
{
        struct object *o;
        int we_knew_they_have = 0;

        if (get_sha1_hex(hex, sha1))
                die("git upload-pack: expected SHA1 object, got '%s'", hex);
        if (!has_sha1_file(sha1))
                return -1;

        o = parse_object(sha1);
        if (!o)
                die("oops (%s)", sha1_to_hex(sha1));
        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 *want)
{
        struct commit_list *work = NULL;

        commit_list_insert_by_date(want, &work);
        while (work) {
                struct commit_list *list = work->next;
                struct commit *commit = work->item;
                free(work);
                work = list;

                if (commit->object.flags & THEY_HAVE) {
                        want->object.flags |= COMMON_KNOWN;
                        break;
                }
                if (!commit->object.parsed)
                        parse_object(commit->object.sha1);
                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))
                                commit_list_insert_by_date(parent, &work);
                }
        }
        want->object.flags |= REACHABLE;
        clear_commit_marks(want, REACHABLE);
        free_commit_list(work);
        return (want->object.flags & COMMON_KNOWN);
}

static int ok_to_give_up(void)
{
        int i;

        if (!have_obj.nr)
                return 0;

        for (i = 0; i < want_obj.nr; i++) {
                struct object *want = want_obj.objects[i].item;

                if (want->flags & COMMON_KNOWN)
                        continue;
                want = deref_tag(want, "a want line", 0);
                if (!want || want->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.
                         */
                        want_obj.objects[i].item->flags |= COMMON_KNOWN;
                        continue;
                }
                if (!reachable((struct commit *)want))
                        return 0;
        }
        return 1;
}

static int get_common_commits(void)
{
        unsigned char sha1[20];
        char last_hex[41];
        int got_common = 0;
        int got_other = 0;
        int sent_ready = 0;

        save_commit_buffer = 0;

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

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

                        if (no_done && sent_ready) {
                                packet_write(1, "ACK %s\n", last_hex);
                                return 0;
                        }
                        if (stateless_rpc)
                                exit(0);
                        got_common = 0;
                        got_other = 0;
                        continue;
                }
                if (!prefixcmp(line, "have ")) {
                        switch (got_sha1(line+5, sha1)) {
                        case -1: /* they have what we do not */
                                got_other = 1;
                                if (multi_ack && ok_to_give_up()) {
                                        const char *hex = sha1_to_hex(sha1);
                                        if (multi_ack == 2) {
                                                sent_ready = 1;
                                                packet_write(1, "ACK %s ready\n", hex);
                                        } else
                                                packet_write(1, "ACK %s continue\n", hex);
                                }
                                break;
                        default:
                                got_common = 1;
                                memcpy(last_hex, sha1_to_hex(sha1), 41);
                                if (multi_ack == 2)
                                        packet_write(1, "ACK %s common\n", last_hex);
                                else if (multi_ack)
                                        packet_write(1, "ACK %s continue\n", last_hex);
                                else if (have_obj.nr == 1)
                                        packet_write(1, "ACK %s\n", last_hex);
                                break;
                        }
                        continue;
                }
                if (!strcmp(line, "done")) {
                        if (have_obj.nr > 0) {
                                if (multi_ack)
                                        packet_write(1, "ACK %s\n", last_hex);
                                return 0;
                        }
                        packet_write(1, "NAK\n");
                        return -1;
                }
                die("git upload-pack: expected SHA1 list, got '%s'", line);
        }
}

static int is_our_ref(struct object *o)
{
        return o->flags &
                ((allow_tip_sha1_in_want ? HIDDEN_REF : 0) | OUR_REF);
}

static void check_non_tip(void)
{
        static const char *argv[] = {
                "rev-list", "--stdin", NULL,
        };
        static struct child_process cmd;
        struct object *o;
        char namebuf[42]; /* ^ + SHA-1 + LF */
        int i;

        /* In the normal in-process case non-tip request can never happen */
        if (!stateless_rpc)
                goto error;

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

        if (start_command(&cmd))
                goto error;

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

        namebuf[0] = '^';
        namebuf[41] = '\n';
        for (i = get_max_object_index(); 0 < i; ) {
                o = get_indexed_object(--i);
                if (!o)
                        continue;
                if (!is_our_ref(o))
                        continue;
                memcpy(namebuf + 1, sha1_to_hex(o->sha1), 40);
                if (write_in_full(cmd.in, namebuf, 42) < 0)
                        goto error;
        }
        namebuf[40] = '\n';
        for (i = 0; i < want_obj.nr; i++) {
                o = want_obj.objects[i].item;
                if (is_our_ref(o))
                        continue;
                memcpy(namebuf, sha1_to_hex(o->sha1), 40);
                if (write_in_full(cmd.in, namebuf, 41) < 0)
                        goto error;
        }
        close(cmd.in);

        sigchain_pop(SIGPIPE);

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

        /*
         * 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;

error:
        /* Pick one of them (we know there at least is one) */
        for (i = 0; i < want_obj.nr; i++) {
                o = want_obj.objects[i].item;
                if (!is_our_ref(o))
                        die("git upload-pack: not our ref %s",
                            sha1_to_hex(o->sha1));
        }
}

static void receive_needs(void)
{
        struct object_array shallows = OBJECT_ARRAY_INIT;
        int depth = 0;
        int has_non_tip = 0;

        shallow_nr = 0;
        for (;;) {
                struct object *o;
                const char *features;
                unsigned char sha1_buf[20];
                char *line = packet_read_line(0, NULL);
                reset_timeout();
                if (!line)
                        break;

                if (!prefixcmp(line, "shallow ")) {
                        unsigned char sha1[20];
                        struct object *object;
                        if (get_sha1_hex(line + 8, sha1))
                                die("invalid shallow line: %s", line);
                        object = parse_object(sha1);
                        if (!object)
                                continue;
                        if (object->type != OBJ_COMMIT)
                                die("invalid shallow object %s", sha1_to_hex(sha1));
                        if (!(object->flags & CLIENT_SHALLOW)) {
                                object->flags |= CLIENT_SHALLOW;
                                add_object_array(object, NULL, &shallows);
                        }
                        continue;
                }
                if (!prefixcmp(line, "deepen ")) {
                        char *end;
                        depth = strtol(line + 7, &end, 0);
                        if (end == line + 7 || depth <= 0)
                                die("Invalid deepen: %s", line);
                        continue;
                }
                if (prefixcmp(line, "want ") ||
                    get_sha1_hex(line+5, sha1_buf))
                        die("git upload-pack: protocol error, "
                            "expected to get sha, not '%s'", line);

                features = line + 45;

                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;

                o = parse_object(sha1_buf);
                if (!o)
                        die("git upload-pack: not our ref %s",
                            sha1_to_hex(sha1_buf));
                if (!(o->flags & WANTED)) {
                        o->flags |= WANTED;
                        if (!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 && shallows.nr == 0)
                return;
        if (depth > 0) {
                struct commit_list *result = NULL, *backup = NULL;
                int i;
                if (depth == INFINITE_DEPTH)
                        for (i = 0; i < shallows.nr; i++) {
                                struct object *object = shallows.objects[i].item;
                                object->flags |= NOT_SHALLOW;
                        }
                else
                        backup = result =
                                get_shallow_commits(&want_obj, depth,
                                                    SHALLOW, NOT_SHALLOW);
                while (result) {
                        struct object *object = &result->item->object;
                        if (!(object->flags & (CLIENT_SHALLOW|NOT_SHALLOW))) {
                                packet_write(1, "shallow %s",
                                                sha1_to_hex(object->sha1));
                                register_shallow(object->sha1);
                                shallow_nr++;
                        }
                        result = result->next;
                }
                free_commit_list(backup);
                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(1, "unshallow %s",
                                        sha1_to_hex(object->sha1));
                                object->flags &= ~CLIENT_SHALLOW;
                                /* make sure the real parents are parsed */
                                unregister_shallow(object->sha1);
                                object->parsed = 0;
                                if (parse_commit((struct commit *)object))
                                        die("invalid commit");
                                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(object->sha1);
                }
                packet_flush(1);
        } else
                if (shallows.nr > 0) {
                        int i;
                        for (i = 0; i < shallows.nr; i++)
                                register_shallow(shallows.objects[i].item->sha1);
                }

        shallow_nr += shallows.nr;
        free(shallows.objects);
}

/* return non-zero if the ref is hidden, otherwise 0 */
static int mark_our_ref(const char *refname, const unsigned char *sha1, int flag, void *cb_data)
{
        struct object *o = lookup_unknown_object(sha1);

        if (ref_is_hidden(refname)) {
                o->flags |= HIDDEN_REF;
                return 1;
        }
        if (!o)
                die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1));
        o->flags |= OUR_REF;
        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 unsigned char *sha1, int flag, void *cb_data)
{
        static const char *capabilities = "multi_ack thin-pack side-band"
                " side-band-64k ofs-delta shallow no-progress"
                " include-tag multi_ack_detailed";
        const char *refname_nons = strip_namespace(refname);
        unsigned char peeled[20];

        if (mark_our_ref(refname, sha1, flag, NULL))
                return 0;

        if (capabilities) {
                struct strbuf symref_info = STRBUF_INIT;

                format_symref_info(&symref_info, cb_data);
                packet_write(1, "%s %s%c%s%s%s%s agent=%s\n",
                             sha1_to_hex(sha1), refname_nons,
                             0, capabilities,
                             allow_tip_sha1_in_want ? " allow-tip-sha1-in-want" : "",
                             stateless_rpc ? " no-done" : "",
                             symref_info.buf,
                             git_user_agent_sanitized());
                strbuf_release(&symref_info);
        } else {
                packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons);
        }
        capabilities = NULL;
        if (!peel_ref(refname, peeled))
                packet_write(1, "%s %s^{}\n", sha1_to_hex(peeled), refname_nons);
        return 0;
}

static int find_symref(const char *refname, const unsigned char *sha1, int flag,
                       void *cb_data)
{
        const char *symref_target;
        struct string_list_item *item;
        unsigned char unused[20];

        if ((flag & REF_ISSYMREF) == 0)
                return 0;
        symref_target = resolve_ref_unsafe(refname, unused, 0, &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 void upload_pack(void)
{
        struct string_list symref = STRING_LIST_INIT_DUP;

        head_ref_namespaced(find_symref, &symref);

        if (advertise_refs || !stateless_rpc) {
                reset_timeout();
                head_ref_namespaced(send_ref, &symref);
                for_each_namespaced_ref(send_ref, &symref);
                packet_flush(1);
        } else {
                head_ref_namespaced(mark_our_ref, NULL);
                for_each_namespaced_ref(mark_our_ref, NULL);
        }
        string_list_clear(&symref, 1);
        if (advertise_refs)
                return;

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

static int upload_pack_config(const char *var, const char *value, void *unused)
{
        if (!strcmp("uploadpack.allowtipsha1inwant", var))
                allow_tip_sha1_in_want = git_config_bool(var, value);
        else if (!strcmp("uploadpack.keepalive", var)) {
                keepalive = git_config_int(var, value);
                if (!keepalive)
                        keepalive = -1;
        }
        return parse_hide_refs_config(var, value, "uploadpack");
}

int main(int argc, char **argv)
{
        char *dir;
        int i;
        int strict = 0;

        git_setup_gettext();

        packet_trace_identity("upload-pack");
        git_extract_argv0_path(argv[0]);
        read_replace_refs = 0;

        for (i = 1; i < argc; i++) {
                char *arg = argv[i];

                if (arg[0] != '-')
                        break;
                if (!strcmp(arg, "--advertise-refs")) {
                        advertise_refs = 1;
                        continue;
                }
                if (!strcmp(arg, "--stateless-rpc")) {
                        stateless_rpc = 1;
                        continue;
                }
                if (!strcmp(arg, "--strict")) {
                        strict = 1;
                        continue;
                }
                if (!prefixcmp(arg, "--timeout=")) {
                        timeout = atoi(arg+10);
                        daemon_mode = 1;
                        continue;
                }
                if (!strcmp(arg, "--")) {
                        i++;
                        break;
                }
        }

        if (i != argc-1)
                usage(upload_pack_usage);

        setup_path();

        dir = argv[i];

        if (!enter_repo(dir, strict))
                die("'%s' does not appear to be a git repository", dir);
        if (is_repository_shallow())
                die("attempt to fetch/clone from a shallow repository");
        git_config(upload_pack_config, NULL);
        upload_pack();
        return 0;
}