/*
 * Builtin "git branch"
 *
 * Copyright (c) 2006 Kristian Høgsberg <krh@redhat.com>
 * Based on git-branch.sh by Junio C Hamano.
 */

#include "cache.h"
#include "color.h"
#include "refs.h"
#include "commit.h"
#include "builtin.h"
#include "remote.h"
#include "parse-options.h"
#include "branch.h"
#include "diff.h"
#include "revision.h"

static const char * const builtin_branch_usage[] = {
        "git branch [options] [-r | -a] [--merged | --no-merged]",
        "git branch [options] [-l] [-f] <branchname> [<start-point>]",
        "git branch [options] [-r] (-d | -D) <branchname>...",
        "git branch [options] (-m | -M) [<oldbranch>] <newbranch>",
        NULL
};

#define REF_LOCAL_BRANCH    0x01
#define REF_REMOTE_BRANCH   0x02

static const char *head;
static unsigned char head_sha1[20];

static int branch_use_color = -1;
static char branch_colors[][COLOR_MAXLEN] = {
        GIT_COLOR_RESET,
        GIT_COLOR_NORMAL,       /* PLAIN */
        GIT_COLOR_RED,          /* REMOTE */
        GIT_COLOR_NORMAL,       /* LOCAL */
        GIT_COLOR_GREEN,        /* CURRENT */
};
enum color_branch {
        BRANCH_COLOR_RESET = 0,
        BRANCH_COLOR_PLAIN = 1,
        BRANCH_COLOR_REMOTE = 2,
        BRANCH_COLOR_LOCAL = 3,
        BRANCH_COLOR_CURRENT = 4
};

static enum merge_filter {
        NO_FILTER = 0,
        SHOW_NOT_MERGED,
        SHOW_MERGED
} merge_filter;
static unsigned char merge_filter_ref[20];

static int parse_branch_color_slot(const char *var, int ofs)
{
        if (!strcasecmp(var+ofs, "plain"))
                return BRANCH_COLOR_PLAIN;
        if (!strcasecmp(var+ofs, "reset"))
                return BRANCH_COLOR_RESET;
        if (!strcasecmp(var+ofs, "remote"))
                return BRANCH_COLOR_REMOTE;
        if (!strcasecmp(var+ofs, "local"))
                return BRANCH_COLOR_LOCAL;
        if (!strcasecmp(var+ofs, "current"))
                return BRANCH_COLOR_CURRENT;
        return -1;
}

static int git_branch_config(const char *var, const char *value, void *cb)
{
        if (!strcmp(var, "color.branch")) {
                branch_use_color = git_config_colorbool(var, value);
                return 0;
        }
        if (!prefixcmp(var, "color.branch.")) {
                int slot = parse_branch_color_slot(var, 13);
                if (slot < 0)
                        return 0;
                if (!value)
                        return config_error_nonbool(var);
                color_parse(value, var, branch_colors[slot]);
                return 0;
        }
        return git_color_default_config(var, value, cb);
}

static const char *branch_get_color(enum color_branch ix)
{
        if (want_color(branch_use_color))
                return branch_colors[ix];
        return "";
}

static int branch_merged(int kind, const char *name,
                         struct commit *rev, struct commit *head_rev)
{
        /*
         * This checks whether the merge bases of branch and HEAD (or
         * the other branch this branch builds upon) contains the
         * branch, which means that the branch has already been merged
         * safely to HEAD (or the other branch).
         */
        struct commit *reference_rev = NULL;
        const char *reference_name = NULL;
        void *reference_name_to_free = NULL;
        int merged;

        if (kind == REF_LOCAL_BRANCH) {
                struct branch *branch = branch_get(name);
                unsigned char sha1[20];

                if (branch &&
                    branch->merge &&
                    branch->merge[0] &&
                    branch->merge[0]->dst &&
                    (reference_name = reference_name_to_free =
                     resolve_refdup(branch->merge[0]->dst, sha1, 1, NULL)) != NULL)
                        reference_rev = lookup_commit_reference(sha1);
        }
        if (!reference_rev)
                reference_rev = head_rev;

        merged = in_merge_bases(rev, &reference_rev, 1);

        /*
         * After the safety valve is fully redefined to "check with
         * upstream, if any, otherwise with HEAD", we should just
         * return the result of the in_merge_bases() above without
         * any of the following code, but during the transition period,
         * a gentle reminder is in order.
         */
        if ((head_rev != reference_rev) &&
            in_merge_bases(rev, &head_rev, 1) != merged) {
                if (merged)
                        warning(_("deleting branch '%s' that has been merged to\n"
                                "         '%s', but not yet merged to HEAD."),
                                name, reference_name);
                else
                        warning(_("not deleting branch '%s' that is not yet merged to\n"
                                "         '%s', even though it is merged to HEAD."),
                                name, reference_name);
        }
        free(reference_name_to_free);
        return merged;
}

static int delete_branches(int argc, const char **argv, int force, int kinds)
{
        struct commit *rev, *head_rev = NULL;
        unsigned char sha1[20];
        char *name = NULL;
        const char *fmt, *remote;
        int i;
        int ret = 0;
        struct strbuf bname = STRBUF_INIT;

        switch (kinds) {
        case REF_REMOTE_BRANCH:
                fmt = "refs/remotes/%s";
                /* TRANSLATORS: This is "remote " in "remote branch '%s' not found" */
                remote = _("remote ");
                force = 1;
                break;
        case REF_LOCAL_BRANCH:
                fmt = "refs/heads/%s";
                remote = "";
                break;
        default:
                die(_("cannot use -a with -d"));
        }

        if (!force) {
                head_rev = lookup_commit_reference(head_sha1);
                if (!head_rev)
                        die(_("Couldn't look up commit object for HEAD"));
        }
        for (i = 0; i < argc; i++, strbuf_release(&bname)) {
                strbuf_branchname(&bname, argv[i]);
                if (kinds == REF_LOCAL_BRANCH && !strcmp(head, bname.buf)) {
                        error(_("Cannot delete the branch '%s' "
                              "which you are currently on."), bname.buf);
                        ret = 1;
                        continue;
                }

                free(name);

                name = xstrdup(mkpath(fmt, bname.buf));
                if (read_ref(name, sha1)) {
                        error(_("%sbranch '%s' not found."),
                                        remote, bname.buf);
                        ret = 1;
                        continue;
                }

                rev = lookup_commit_reference(sha1);
                if (!rev) {
                        error(_("Couldn't look up commit object for '%s'"), name);
                        ret = 1;
                        continue;
                }

                if (!force && !branch_merged(kinds, bname.buf, rev, head_rev)) {
                        error(_("The branch '%s' is not fully merged.\n"
                              "If you are sure you want to delete it, "
                              "run 'git branch -D %s'."), bname.buf, bname.buf);
                        ret = 1;
                        continue;
                }

                if (delete_ref(name, sha1, 0)) {
                        error(_("Error deleting %sbranch '%s'"), remote,
                              bname.buf);
                        ret = 1;
                } else {
                        struct strbuf buf = STRBUF_INIT;
                        printf(_("Deleted %sbranch %s (was %s).\n"), remote,
                               bname.buf,
                               find_unique_abbrev(sha1, DEFAULT_ABBREV));
                        strbuf_addf(&buf, "branch.%s", bname.buf);
                        if (git_config_rename_section(buf.buf, NULL) < 0)
                                warning(_("Update of config-file failed"));
                        strbuf_release(&buf);
                }
        }

        free(name);

        return(ret);
}

struct ref_item {
        char *name;
        char *dest;
        unsigned int kind, len;
        struct commit *commit;
};

struct ref_list {
        struct rev_info revs;
        int index, alloc, maxwidth, verbose, abbrev;
        struct ref_item *list;
        struct commit_list *with_commit;
        int kinds;
};

static char *resolve_symref(const char *src, const char *prefix)
{
        unsigned char sha1[20];
        int flag;
        const char *dst, *cp;

        dst = resolve_ref_unsafe(src, sha1, 0, &flag);
        if (!(dst && (flag & REF_ISSYMREF)))
                return NULL;
        if (prefix && (cp = skip_prefix(dst, prefix)))
                dst = cp;
        return xstrdup(dst);
}

struct append_ref_cb {
        struct ref_list *ref_list;
        const char **pattern;
        int ret;
};

static int match_patterns(const char **pattern, const char *refname)
{
        if (!*pattern)
                return 1; /* no pattern always matches */
        while (*pattern) {
                if (!fnmatch(*pattern, refname, 0))
                        return 1;
                pattern++;
        }
        return 0;
}

static int append_ref(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
{
        struct append_ref_cb *cb = (struct append_ref_cb *)(cb_data);
        struct ref_list *ref_list = cb->ref_list;
        struct ref_item *newitem;
        struct commit *commit;
        int kind, i;
        const char *prefix, *orig_refname = refname;

        static struct {
                int kind;
                const char *prefix;
                int pfxlen;
        } ref_kind[] = {
                { REF_LOCAL_BRANCH, "refs/heads/", 11 },
                { REF_REMOTE_BRANCH, "refs/remotes/", 13 },
        };

        /* Detect kind */
        for (i = 0; i < ARRAY_SIZE(ref_kind); i++) {
                prefix = ref_kind[i].prefix;
                if (strncmp(refname, prefix, ref_kind[i].pfxlen))
                        continue;
                kind = ref_kind[i].kind;
                refname += ref_kind[i].pfxlen;
                break;
        }
        if (ARRAY_SIZE(ref_kind) <= i)
                return 0;

        /* Don't add types the caller doesn't want */
        if ((kind & ref_list->kinds) == 0)
                return 0;

        if (!match_patterns(cb->pattern, refname))
                return 0;

        commit = NULL;
        if (ref_list->verbose || ref_list->with_commit || merge_filter != NO_FILTER) {
                commit = lookup_commit_reference_gently(sha1, 1);
                if (!commit) {
                        cb->ret = error(_("branch '%s' does not point at a commit"), refname);
                        return 0;
                }

                /* Filter with with_commit if specified */
                if (!is_descendant_of(commit, ref_list->with_commit))
                        return 0;

                if (merge_filter != NO_FILTER)
                        add_pending_object(&ref_list->revs,
                                           (struct object *)commit, refname);
        }

        ALLOC_GROW(ref_list->list, ref_list->index + 1, ref_list->alloc);

        /* Record the new item */
        newitem = &(ref_list->list[ref_list->index++]);
        newitem->name = xstrdup(refname);
        newitem->kind = kind;
        newitem->commit = commit;
        newitem->len = strlen(refname);
        newitem->dest = resolve_symref(orig_refname, prefix);
        /* adjust for "remotes/" */
        if (newitem->kind == REF_REMOTE_BRANCH &&
            ref_list->kinds != REF_REMOTE_BRANCH)
                newitem->len += 8;
        if (newitem->len > ref_list->maxwidth)
                ref_list->maxwidth = newitem->len;

        return 0;
}

static void free_ref_list(struct ref_list *ref_list)
{
        int i;

        for (i = 0; i < ref_list->index; i++) {
                free(ref_list->list[i].name);
                free(ref_list->list[i].dest);
        }
        free(ref_list->list);
}

static int ref_cmp(const void *r1, const void *r2)
{
        struct ref_item *c1 = (struct ref_item *)(r1);
        struct ref_item *c2 = (struct ref_item *)(r2);

        if (c1->kind != c2->kind)
                return c1->kind - c2->kind;
        return strcmp(c1->name, c2->name);
}

static void fill_tracking_info(struct strbuf *stat, const char *branch_name,
                int show_upstream_ref)
{
        int ours, theirs;
        struct branch *branch = branch_get(branch_name);

        if (!stat_tracking_info(branch, &ours, &theirs)) {
                if (branch && branch->merge && branch->merge[0]->dst &&
                    show_upstream_ref)
                        strbuf_addf(stat, "[%s] ",
                            shorten_unambiguous_ref(branch->merge[0]->dst, 0));
                return;
        }

        strbuf_addch(stat, '[');
        if (show_upstream_ref)
                strbuf_addf(stat, "%s: ",
                        shorten_unambiguous_ref(branch->merge[0]->dst, 0));
        if (!ours)
                strbuf_addf(stat, _("behind %d] "), theirs);
        else if (!theirs)
                strbuf_addf(stat, _("ahead %d] "), ours);
        else
                strbuf_addf(stat, _("ahead %d, behind %d] "), ours, theirs);
}

static int matches_merge_filter(struct commit *commit)
{
        int is_merged;

        if (merge_filter == NO_FILTER)
                return 1;

        is_merged = !!(commit->object.flags & UNINTERESTING);
        return (is_merged == (merge_filter == SHOW_MERGED));
}

static void add_verbose_info(struct strbuf *out, struct ref_item *item,
                             int verbose, int abbrev)
{
        struct strbuf subject = STRBUF_INIT, stat = STRBUF_INIT;
        const char *sub = " **** invalid ref ****";
        struct commit *commit = item->commit;

        if (commit && !parse_commit(commit)) {
                pp_commit_easy(CMIT_FMT_ONELINE, commit, &subject);
                sub = subject.buf;
        }

        if (item->kind == REF_LOCAL_BRANCH)
                fill_tracking_info(&stat, item->name, verbose > 1);

        strbuf_addf(out, " %s %s%s",
                find_unique_abbrev(item->commit->object.sha1, abbrev),
                stat.buf, sub);
        strbuf_release(&stat);
        strbuf_release(&subject);
}

static void print_ref_item(struct ref_item *item, int maxwidth, int verbose,
                           int abbrev, int current, char *prefix)
{
        char c;
        int color;
        struct commit *commit = item->commit;
        struct strbuf out = STRBUF_INIT, name = STRBUF_INIT;

        if (!matches_merge_filter(commit))
                return;

        switch (item->kind) {
        case REF_LOCAL_BRANCH:
                color = BRANCH_COLOR_LOCAL;
                break;
        case REF_REMOTE_BRANCH:
                color = BRANCH_COLOR_REMOTE;
                break;
        default:
                color = BRANCH_COLOR_PLAIN;
                break;
        }

        c = ' ';
        if (current) {
                c = '*';
                color = BRANCH_COLOR_CURRENT;
        }

        strbuf_addf(&name, "%s%s", prefix, item->name);
        if (verbose)
                strbuf_addf(&out, "%c %s%-*s%s", c, branch_get_color(color),
                            maxwidth, name.buf,
                            branch_get_color(BRANCH_COLOR_RESET));
        else
                strbuf_addf(&out, "%c %s%s%s", c, branch_get_color(color),
                            name.buf, branch_get_color(BRANCH_COLOR_RESET));

        if (item->dest)
                strbuf_addf(&out, " -> %s", item->dest);
        else if (verbose)
                /* " f7c0c00 [ahead 58, behind 197] vcs-svn: drop obj_pool.h" */
                add_verbose_info(&out, item, verbose, abbrev);
        printf("%s\n", out.buf);
        strbuf_release(&name);
        strbuf_release(&out);
}

static int calc_maxwidth(struct ref_list *refs)
{
        int i, w = 0;
        for (i = 0; i < refs->index; i++) {
                if (!matches_merge_filter(refs->list[i].commit))
                        continue;
                if (refs->list[i].len > w)
                        w = refs->list[i].len;
        }
        return w;
}


static void show_detached(struct ref_list *ref_list)
{
        struct commit *head_commit = lookup_commit_reference_gently(head_sha1, 1);

        if (head_commit && is_descendant_of(head_commit, ref_list->with_commit)) {
                struct ref_item item;
                item.name = xstrdup(_("(no branch)"));
                item.len = strlen(item.name);
                item.kind = REF_LOCAL_BRANCH;
                item.dest = NULL;
                item.commit = head_commit;
                if (item.len > ref_list->maxwidth)
                        ref_list->maxwidth = item.len;
                print_ref_item(&item, ref_list->maxwidth, ref_list->verbose, ref_list->abbrev, 1, "");
                free(item.name);
        }
}

static int print_ref_list(int kinds, int detached, int verbose, int abbrev, struct commit_list *with_commit, const char **pattern)
{
        int i;
        struct append_ref_cb cb;
        struct ref_list ref_list;

        memset(&ref_list, 0, sizeof(ref_list));
        ref_list.kinds = kinds;
        ref_list.verbose = verbose;
        ref_list.abbrev = abbrev;
        ref_list.with_commit = with_commit;
        if (merge_filter != NO_FILTER)
                init_revisions(&ref_list.revs, NULL);
        cb.ref_list = &ref_list;
        cb.pattern = pattern;
        cb.ret = 0;
        for_each_rawref(append_ref, &cb);
        if (merge_filter != NO_FILTER) {
                struct commit *filter;
                filter = lookup_commit_reference_gently(merge_filter_ref, 0);
                filter->object.flags |= UNINTERESTING;
                add_pending_object(&ref_list.revs,
                                   (struct object *) filter, "");
                ref_list.revs.limited = 1;
                prepare_revision_walk(&ref_list.revs);
                if (verbose)
                        ref_list.maxwidth = calc_maxwidth(&ref_list);
        }

        qsort(ref_list.list, ref_list.index, sizeof(struct ref_item), ref_cmp);

        detached = (detached && (kinds & REF_LOCAL_BRANCH));
        if (detached && match_patterns(pattern, "HEAD"))
                show_detached(&ref_list);

        for (i = 0; i < ref_list.index; i++) {
                int current = !detached &&
                        (ref_list.list[i].kind == REF_LOCAL_BRANCH) &&
                        !strcmp(ref_list.list[i].name, head);
                char *prefix = (kinds != REF_REMOTE_BRANCH &&
                                ref_list.list[i].kind == REF_REMOTE_BRANCH)
                                ? "remotes/" : "";
                print_ref_item(&ref_list.list[i], ref_list.maxwidth, verbose,
                               abbrev, current, prefix);
        }

        free_ref_list(&ref_list);

        if (cb.ret)
                error(_("some refs could not be read"));

        return cb.ret;
}

static void rename_branch(const char *oldname, const char *newname, int force)
{
        struct strbuf oldref = STRBUF_INIT, newref = STRBUF_INIT, logmsg = STRBUF_INIT;
        struct strbuf oldsection = STRBUF_INIT, newsection = STRBUF_INIT;
        int recovery = 0;
        int clobber_head_ok;

        if (!oldname)
                die(_("cannot rename the current branch while not on any."));

        if (strbuf_check_branch_ref(&oldref, oldname)) {
                /*
                 * Bad name --- this could be an attempt to rename a
                 * ref that we used to allow to be created by accident.
                 */
                if (ref_exists(oldref.buf))
                        recovery = 1;
                else
                        die(_("Invalid branch name: '%s'"), oldname);
        }

        /*
         * A command like "git branch -M currentbranch currentbranch" cannot
         * cause the worktree to become inconsistent with HEAD, so allow it.
         */
        clobber_head_ok = !strcmp(oldname, newname);

        validate_new_branchname(newname, &newref, force, clobber_head_ok);

        strbuf_addf(&logmsg, "Branch: renamed %s to %s",
                 oldref.buf, newref.buf);

        if (rename_ref(oldref.buf, newref.buf, logmsg.buf))
                die(_("Branch rename failed"));
        strbuf_release(&logmsg);

        if (recovery)
                warning(_("Renamed a misnamed branch '%s' away"), oldref.buf + 11);

        /* no need to pass logmsg here as HEAD didn't really move */
        if (!strcmp(oldname, head) && create_symref("HEAD", newref.buf, NULL))
                die(_("Branch renamed to %s, but HEAD is not updated!"), newname);

        strbuf_addf(&oldsection, "branch.%s", oldref.buf + 11);
        strbuf_release(&oldref);
        strbuf_addf(&newsection, "branch.%s", newref.buf + 11);
        strbuf_release(&newref);
        if (git_config_rename_section(oldsection.buf, newsection.buf) < 0)
                die(_("Branch is renamed, but update of config-file failed"));
        strbuf_release(&oldsection);
        strbuf_release(&newsection);
}

static int opt_parse_merge_filter(const struct option *opt, const char *arg, int unset)
{
        merge_filter = ((opt->long_name[0] == 'n')
                        ? SHOW_NOT_MERGED
                        : SHOW_MERGED);
        if (unset)
                merge_filter = SHOW_NOT_MERGED; /* b/c for --no-merged */
        if (!arg)
                arg = "HEAD";
        if (get_sha1(arg, merge_filter_ref))
                die(_("malformed object name %s"), arg);
        return 0;
}

static const char edit_description[] = "BRANCH_DESCRIPTION";

static int edit_branch_description(const char *branch_name)
{
        FILE *fp;
        int status;
        struct strbuf buf = STRBUF_INIT;
        struct strbuf name = STRBUF_INIT;

        read_branch_desc(&buf, branch_name);
        if (!buf.len || buf.buf[buf.len-1] != '\n')
                strbuf_addch(&buf, '\n');
        strbuf_addf(&buf,
                    "# Please edit the description for the branch\n"
                    "#   %s\n"
                    "# Lines starting with '#' will be stripped.\n",
                    branch_name);
        fp = fopen(git_path(edit_description), "w");
        if ((fwrite(buf.buf, 1, buf.len, fp) < buf.len) || fclose(fp)) {
                strbuf_release(&buf);
                return error(_("could not write branch description template: %s\n"),
                             strerror(errno));
        }
        strbuf_reset(&buf);
        if (launch_editor(git_path(edit_description), &buf, NULL)) {
                strbuf_release(&buf);
                return -1;
        }
        stripspace(&buf, 1);

        strbuf_addf(&name, "branch.%s.description", branch_name);
        status = git_config_set(name.buf, buf.buf);
        strbuf_release(&name);
        strbuf_release(&buf);

        return status;
}

int cmd_branch(int argc, const char **argv, const char *prefix)
{
        int delete = 0, rename = 0, force_create = 0, list = 0;
        int verbose = 0, abbrev = -1, detached = 0;
        int reflog = 0, edit_description = 0;
        enum branch_track track;
        int kinds = REF_LOCAL_BRANCH;
        struct commit_list *with_commit = NULL;

        struct option options[] = {
                OPT_GROUP("Generic options"),
                OPT__VERBOSE(&verbose,
                        "show hash and subject, give twice for upstream branch"),
                OPT_SET_INT('t', "track",  &track, "set up tracking mode (see git-pull(1))",
                        BRANCH_TRACK_EXPLICIT),
                OPT_SET_INT( 0, "set-upstream",  &track, "change upstream info",
                        BRANCH_TRACK_OVERRIDE),
                OPT__COLOR(&branch_use_color, "use colored output"),
                OPT_SET_INT('r', "remotes",     &kinds, "act on remote-tracking branches",
                        REF_REMOTE_BRANCH),
                {
                        OPTION_CALLBACK, 0, "contains", &with_commit, "commit",
                        "print only branches that contain the commit",
                        PARSE_OPT_LASTARG_DEFAULT,
                        parse_opt_with_commit, (intptr_t)"HEAD",
                },
                {
                        OPTION_CALLBACK, 0, "with", &with_commit, "commit",
                        "print only branches that contain the commit",
                        PARSE_OPT_HIDDEN | PARSE_OPT_LASTARG_DEFAULT,
                        parse_opt_with_commit, (intptr_t) "HEAD",
                },
                OPT__ABBREV(&abbrev),

                OPT_GROUP("Specific git-branch actions:"),
                OPT_SET_INT('a', "all", &kinds, "list both remote-tracking and local branches",
                        REF_REMOTE_BRANCH | REF_LOCAL_BRANCH),
                OPT_BIT('d', "delete", &delete, "delete fully merged branch", 1),
                OPT_BIT('D', NULL, &delete, "delete branch (even if not merged)", 2),
                OPT_BIT('m', "move", &rename, "move/rename a branch and its reflog", 1),
                OPT_BIT('M', NULL, &rename, "move/rename a branch, even if target exists", 2),
                OPT_BOOLEAN(0, "list", &list, "list branch names"),
                OPT_BOOLEAN('l', "create-reflog", &reflog, "create the branch's reflog"),
                OPT_BOOLEAN(0, "edit-description", &edit_description,
                            "edit the description for the branch"),
                OPT__FORCE(&force_create, "force creation (when already exists)"),
                {
                        OPTION_CALLBACK, 0, "no-merged", &merge_filter_ref,
                        "commit", "print only not merged branches",
                        PARSE_OPT_LASTARG_DEFAULT | PARSE_OPT_NONEG,
                        opt_parse_merge_filter, (intptr_t) "HEAD",
                },
                {
                        OPTION_CALLBACK, 0, "merged", &merge_filter_ref,
                        "commit", "print only merged branches",
                        PARSE_OPT_LASTARG_DEFAULT | PARSE_OPT_NONEG,
                        opt_parse_merge_filter, (intptr_t) "HEAD",
                },
                OPT_END(),
        };

        if (argc == 2 && !strcmp(argv[1], "-h"))
                usage_with_options(builtin_branch_usage, options);

        git_config(git_branch_config, NULL);

        track = git_branch_track;

        head = resolve_refdup("HEAD", head_sha1, 0, NULL);
        if (!head)
                die(_("Failed to resolve HEAD as a valid ref."));
        if (!strcmp(head, "HEAD")) {
                detached = 1;
        } else {
                if (prefixcmp(head, "refs/heads/"))
                        die(_("HEAD not found below refs/heads!"));
                head += 11;
        }
        hashcpy(merge_filter_ref, head_sha1);

        argc = parse_options(argc, argv, prefix, options, builtin_branch_usage,
                             0);

        if (!delete && !rename && !edit_description && argc == 0)
                list = 1;

        if (!!delete + !!rename + !!force_create + !!list > 1)
                usage_with_options(builtin_branch_usage, options);

        if (abbrev == -1)
                abbrev = DEFAULT_ABBREV;

        if (delete)
                return delete_branches(argc, argv, delete > 1, kinds);
        else if (list)
                return print_ref_list(kinds, detached, verbose, abbrev,
                                      with_commit, argv);
        else if (edit_description) {
                const char *branch_name;
                struct strbuf branch_ref = STRBUF_INIT;

                if (detached)
                        die("Cannot give description to detached HEAD");
                if (!argc)
                        branch_name = head;
                else if (argc == 1)
                        branch_name = argv[0];
                else
                        usage_with_options(builtin_branch_usage, options);

                strbuf_addf(&branch_ref, "refs/heads/%s", branch_name);
                if (!ref_exists(branch_ref.buf)) {
                        strbuf_release(&branch_ref);

                        if (!argc)
                                return error("No commit on branch '%s' yet.",
                                             branch_name);
                        else
                                return error("No such branch '%s'.", branch_name);
                }
                strbuf_release(&branch_ref);

                if (edit_branch_description(branch_name))
                        return 1;
        } else if (rename) {
                if (argc == 1)
                        rename_branch(head, argv[0], rename > 1);
                else if (argc == 2)
                        rename_branch(argv[0], argv[1], rename > 1);
                else
                        usage_with_options(builtin_branch_usage, options);
        } else if (argc > 0 && argc <= 2) {
                if (kinds != REF_LOCAL_BRANCH)
                        die(_("-a and -r options to 'git branch' do not make sense with a branch name"));
                create_branch(head, argv[0], (argc == 2) ? argv[1] : head,
                              force_create, reflog, 0, track);
        } else
                usage_with_options(builtin_branch_usage, options);

        return 0;
}