ref-filter: add new "describe" atom

[thirdparty/git.git] / ref-filter.c

#include "git-compat-util.h"
#include "environment.h"
#include "gettext.h"
#include "config.h"
#include "gpg-interface.h"
#include "hex.h"
#include "parse-options.h"
#include "run-command.h"
#include "refs.h"
#include "wildmatch.h"
#include "object-name.h"
#include "object-store-ll.h"
#include "oid-array.h"
#include "repository.h"
#include "commit.h"
#include "remote.h"
#include "color.h"
#include "tag.h"
#include "quote.h"
#include "ref-filter.h"
#include "revision.h"
#include "utf8.h"
#include "version.h"
#include "versioncmp.h"
#include "trailer.h"
#include "wt-status.h"
#include "commit-slab.h"
#include "commit-graph.h"
#include "commit-reach.h"
#include "worktree.h"
#include "hashmap.h"
#include "strvec.h"

static struct ref_msg {
        const char *gone;
        const char *ahead;
        const char *behind;
        const char *ahead_behind;
} msgs = {
         /* Untranslated plumbing messages: */
        "gone",
        "ahead %d",
        "behind %d",
        "ahead %d, behind %d"
};

void setup_ref_filter_porcelain_msg(void)
{
        msgs.gone = _("gone");
        msgs.ahead = _("ahead %d");
        msgs.behind = _("behind %d");
        msgs.ahead_behind = _("ahead %d, behind %d");
}

typedef enum { FIELD_STR, FIELD_ULONG, FIELD_TIME } cmp_type;
typedef enum { COMPARE_EQUAL, COMPARE_UNEQUAL, COMPARE_NONE } cmp_status;
typedef enum { SOURCE_NONE = 0, SOURCE_OBJ, SOURCE_OTHER } info_source;

struct align {
        align_type position;
        unsigned int width;
};

struct if_then_else {
        cmp_status cmp_status;
        const char *str;
        unsigned int then_atom_seen : 1,
                else_atom_seen : 1,
                condition_satisfied : 1;
};

struct refname_atom {
        enum { R_NORMAL, R_SHORT, R_LSTRIP, R_RSTRIP } option;
        int lstrip, rstrip;
};

static struct ref_trailer_buf {
        struct string_list filter_list;
        struct strbuf sepbuf;
        struct strbuf kvsepbuf;
} ref_trailer_buf = {STRING_LIST_INIT_NODUP, STRBUF_INIT, STRBUF_INIT};

static struct expand_data {
        struct object_id oid;
        enum object_type type;
        unsigned long size;
        off_t disk_size;
        struct object_id delta_base_oid;
        void *content;

        struct object_info info;
} oi, oi_deref;

struct ref_to_worktree_entry {
        struct hashmap_entry ent;
        struct worktree *wt; /* key is wt->head_ref */
};

static int ref_to_worktree_map_cmpfnc(const void *lookupdata UNUSED,
                                      const struct hashmap_entry *eptr,
                                      const struct hashmap_entry *kptr,
                                      const void *keydata_aka_refname)
{
        const struct ref_to_worktree_entry *e, *k;

        e = container_of(eptr, const struct ref_to_worktree_entry, ent);
        k = container_of(kptr, const struct ref_to_worktree_entry, ent);

        return strcmp(e->wt->head_ref,
                keydata_aka_refname ? keydata_aka_refname : k->wt->head_ref);
}

static struct ref_to_worktree_map {
        struct hashmap map;
        struct worktree **worktrees;
} ref_to_worktree_map;

/*
 * The enum atom_type is used as the index of valid_atom array.
 * In the atom parsing stage, it will be passed to used_atom.atom_type
 * as the identifier of the atom type. We can check the type of used_atom
 * entry by `if (used_atom[i].atom_type == ATOM_*)`.
 */
enum atom_type {
        ATOM_REFNAME,
        ATOM_OBJECTTYPE,
        ATOM_OBJECTSIZE,
        ATOM_OBJECTNAME,
        ATOM_DELTABASE,
        ATOM_TREE,
        ATOM_PARENT,
        ATOM_NUMPARENT,
        ATOM_OBJECT,
        ATOM_TYPE,
        ATOM_TAG,
        ATOM_AUTHOR,
        ATOM_AUTHORNAME,
        ATOM_AUTHOREMAIL,
        ATOM_AUTHORDATE,
        ATOM_COMMITTER,
        ATOM_COMMITTERNAME,
        ATOM_COMMITTEREMAIL,
        ATOM_COMMITTERDATE,
        ATOM_TAGGER,
        ATOM_TAGGERNAME,
        ATOM_TAGGEREMAIL,
        ATOM_TAGGERDATE,
        ATOM_CREATOR,
        ATOM_CREATORDATE,
        ATOM_DESCRIBE,
        ATOM_SUBJECT,
        ATOM_BODY,
        ATOM_TRAILERS,
        ATOM_CONTENTS,
        ATOM_SIGNATURE,
        ATOM_RAW,
        ATOM_UPSTREAM,
        ATOM_PUSH,
        ATOM_SYMREF,
        ATOM_FLAG,
        ATOM_HEAD,
        ATOM_COLOR,
        ATOM_WORKTREEPATH,
        ATOM_ALIGN,
        ATOM_END,
        ATOM_IF,
        ATOM_THEN,
        ATOM_ELSE,
        ATOM_REST,
        ATOM_AHEADBEHIND,
};

/*
 * An atom is a valid field atom listed below, possibly prefixed with
 * a "*" to denote deref_tag().
 *
 * We parse given format string and sort specifiers, and make a list
 * of properties that we need to extract out of objects.  ref_array_item
 * structure will hold an array of values extracted that can be
 * indexed with the "atom number", which is an index into this
 * array.
 */
static struct used_atom {
        enum atom_type atom_type;
        const char *name;
        cmp_type type;
        info_source source;
        union {
                char color[COLOR_MAXLEN];
                struct align align;
                struct {
                        enum {
                                RR_REF, RR_TRACK, RR_TRACKSHORT, RR_REMOTE_NAME, RR_REMOTE_REF
                        } option;
                        struct refname_atom refname;
                        unsigned int nobracket : 1, push : 1, push_remote : 1;
                } remote_ref;
                struct {
                        enum { C_BARE, C_BODY, C_BODY_DEP, C_LENGTH, C_LINES,
                               C_SIG, C_SUB, C_SUB_SANITIZE, C_TRAILERS } option;
                        struct process_trailer_options trailer_opts;
                        unsigned int nlines;
                } contents;
                struct {
                        enum { RAW_BARE, RAW_LENGTH } option;
                } raw_data;
                struct {
                        cmp_status cmp_status;
                        const char *str;
                } if_then_else;
                struct {
                        enum { O_FULL, O_LENGTH, O_SHORT } option;
                        unsigned int length;
                } oid;
                struct {
                        enum { O_SIZE, O_SIZE_DISK } option;
                } objectsize;
                struct email_option {
                        enum { EO_RAW, EO_TRIM, EO_LOCALPART } option;
                } email_option;
                struct {
                        enum { S_BARE, S_GRADE, S_SIGNER, S_KEY,
                               S_FINGERPRINT, S_PRI_KEY_FP, S_TRUST_LEVEL } option;
                } signature;
                const char **describe_args;
                struct refname_atom refname;
                char *head;
        } u;
} *used_atom;
static int used_atom_cnt, need_tagged, need_symref;

/*
 * Expand string, append it to strbuf *sb, then return error code ret.
 * Allow to save few lines of code.
 */
__attribute__((format (printf, 3, 4)))
static int strbuf_addf_ret(struct strbuf *sb, int ret, const char *fmt, ...)
{
        va_list ap;
        va_start(ap, fmt);
        strbuf_vaddf(sb, fmt, ap);
        va_end(ap);
        return ret;
}

static int err_no_arg(struct strbuf *sb, const char *name)
{
        size_t namelen = strchrnul(name, ':') - name;
        strbuf_addf(sb, _("%%(%.*s) does not take arguments"),
                    (int)namelen, name);
        return -1;
}

static int err_bad_arg(struct strbuf *sb, const char *name, const char *arg)
{
        size_t namelen = strchrnul(name, ':') - name;
        strbuf_addf(sb, _("unrecognized %%(%.*s) argument: %s"),
                    (int)namelen, name, arg);
        return -1;
}

/*
 * Parse option of name "candidate" in the option string "to_parse" of
 * the form
 *
 *      "candidate1[=val1],candidate2[=val2],candidate3[=val3],..."
 *
 * The remaining part of "to_parse" is stored in "end" (if we are
 * parsing the last candidate, then this is NULL) and the value of
 * the candidate is stored in "valuestart" and its length in "valuelen",
 * that is the portion after "=". Since it is possible for a "candidate"
 * to not have a value, in such cases, "valuestart" is set to point to
 * NULL and "valuelen" to 0.
 *
 * The function returns 1 on success. It returns 0 if we don't find
 * "candidate" in "to_parse" or we find "candidate" but it is followed
 * by more chars (for example, "candidatefoo"), that is, we don't find
 * an exact match.
 *
 * This function only does the above for one "candidate" at a time. So
 * it has to be called each time trying to parse a "candidate" in the
 * option string "to_parse".
 */
static int match_atom_arg_value(const char *to_parse, const char *candidate,
                                const char **end, const char **valuestart,
                                size_t *valuelen)
{
        const char *atom;

        if (!skip_prefix(to_parse, candidate, &atom))
                return 0; /* definitely not "candidate" */

        if (*atom == '=') {
                /* we just saw "candidate=" */
                *valuestart = atom + 1;
                atom = strchrnul(*valuestart, ',');
                *valuelen = atom - *valuestart;
        } else if (*atom != ',' && *atom != '\0') {
                /* key begins with "candidate" but has more chars */
                return 0;
        } else {
                /* just "candidate" without "=val" */
                *valuestart = NULL;
                *valuelen = 0;
        }

        /* atom points at either the ',' or NUL after this key[=val] */
        if (*atom == ',')
                atom++;
        else if (*atom)
                BUG("Why is *atom not NULL yet?");

        *end = atom;
        return 1;
}

/*
 * Parse boolean option of name "candidate" in the option list "to_parse"
 * of the form
 *
 *      "candidate1[=bool1],candidate2[=bool2],candidate3[=bool3],..."
 *
 * The remaining part of "to_parse" is stored in "end" (if we are parsing
 * the last candidate, then this is NULL) and the value (if given) is
 * parsed and stored in "val", so "val" always points to either 0 or 1.
 * If the value is not given, then "val" is set to point to 1.
 *
 * The boolean value is parsed using "git_parse_maybe_bool()", so the
 * accepted values are
 *
 *      to set true  - "1", "yes", "true"
 *      to set false - "0", "no", "false"
 *
 * This function returns 1 on success. It returns 0 when we don't find
 * an exact match for "candidate" or when the boolean value given is
 * not valid.
 */
static int match_atom_bool_arg(const char *to_parse, const char *candidate,
                                const char **end, int *val)
{
        const char *argval;
        char *strval;
        size_t arglen;
        int v;

        if (!match_atom_arg_value(to_parse, candidate, end, &argval, &arglen))
                return 0;

        if (!argval) {
                *val = 1;
                return 1;
        }

        strval = xstrndup(argval, arglen);
        v = git_parse_maybe_bool(strval);
        free(strval);

        if (v == -1)
                return 0;

        *val = v;

        return 1;
}

static int color_atom_parser(struct ref_format *format, struct used_atom *atom,
                             const char *color_value, struct strbuf *err)
{
        if (!color_value)
                return strbuf_addf_ret(err, -1, _("expected format: %%(color:<color>)"));
        if (color_parse(color_value, atom->u.color) < 0)
                return strbuf_addf_ret(err, -1, _("unrecognized color: %%(color:%s)"),
                                       color_value);
        /*
         * We check this after we've parsed the color, which lets us complain
         * about syntactically bogus color names even if they won't be used.
         */
        if (!want_color(format->use_color))
                color_parse("", atom->u.color);
        return 0;
}

static int refname_atom_parser_internal(struct refname_atom *atom, const char *arg,
                                         const char *name, struct strbuf *err)
{
        if (!arg)
                atom->option = R_NORMAL;
        else if (!strcmp(arg, "short"))
                atom->option = R_SHORT;
        else if (skip_prefix(arg, "lstrip=", &arg) ||
                 skip_prefix(arg, "strip=", &arg)) {
                atom->option = R_LSTRIP;
                if (strtol_i(arg, 10, &atom->lstrip))
                        return strbuf_addf_ret(err, -1, _("Integer value expected refname:lstrip=%s"), arg);
        } else if (skip_prefix(arg, "rstrip=", &arg)) {
                atom->option = R_RSTRIP;
                if (strtol_i(arg, 10, &atom->rstrip))
                        return strbuf_addf_ret(err, -1, _("Integer value expected refname:rstrip=%s"), arg);
        } else
                return err_bad_arg(err, name, arg);
        return 0;
}

static int remote_ref_atom_parser(struct ref_format *format UNUSED,
                                  struct used_atom *atom,
                                  const char *arg, struct strbuf *err)
{
        struct string_list params = STRING_LIST_INIT_DUP;
        int i;

        if (!strcmp(atom->name, "push") || starts_with(atom->name, "push:"))
                atom->u.remote_ref.push = 1;

        if (!arg) {
                atom->u.remote_ref.option = RR_REF;
                return refname_atom_parser_internal(&atom->u.remote_ref.refname,
                                                    arg, atom->name, err);
        }

        atom->u.remote_ref.nobracket = 0;
        string_list_split(&params, arg, ',', -1);

        for (i = 0; i < params.nr; i++) {
                const char *s = params.items[i].string;

                if (!strcmp(s, "track"))
                        atom->u.remote_ref.option = RR_TRACK;
                else if (!strcmp(s, "trackshort"))
                        atom->u.remote_ref.option = RR_TRACKSHORT;
                else if (!strcmp(s, "nobracket"))
                        atom->u.remote_ref.nobracket = 1;
                else if (!strcmp(s, "remotename")) {
                        atom->u.remote_ref.option = RR_REMOTE_NAME;
                        atom->u.remote_ref.push_remote = 1;
                } else if (!strcmp(s, "remoteref")) {
                        atom->u.remote_ref.option = RR_REMOTE_REF;
                        atom->u.remote_ref.push_remote = 1;
                } else {
                        atom->u.remote_ref.option = RR_REF;
                        if (refname_atom_parser_internal(&atom->u.remote_ref.refname,
                                                         arg, atom->name, err)) {
                                string_list_clear(&params, 0);
                                return -1;
                        }
                }
        }

        string_list_clear(&params, 0);
        return 0;
}

static int objecttype_atom_parser(struct ref_format *format UNUSED,
                                  struct used_atom *atom,
                                  const char *arg, struct strbuf *err)
{
        if (arg)
                return err_no_arg(err, "objecttype");
        if (*atom->name == '*')
                oi_deref.info.typep = &oi_deref.type;
        else
                oi.info.typep = &oi.type;
        return 0;
}

static int objectsize_atom_parser(struct ref_format *format UNUSED,
                                  struct used_atom *atom,
                                  const char *arg, struct strbuf *err)
{
        if (!arg) {
                atom->u.objectsize.option = O_SIZE;
                if (*atom->name == '*')
                        oi_deref.info.sizep = &oi_deref.size;
                else
                        oi.info.sizep = &oi.size;
        } else if (!strcmp(arg, "disk")) {
                atom->u.objectsize.option = O_SIZE_DISK;
                if (*atom->name == '*')
                        oi_deref.info.disk_sizep = &oi_deref.disk_size;
                else
                        oi.info.disk_sizep = &oi.disk_size;
        } else
                return err_bad_arg(err, "objectsize", arg);
        return 0;
}

static int deltabase_atom_parser(struct ref_format *format UNUSED,
                                 struct used_atom *atom,
                                 const char *arg, struct strbuf *err)
{
        if (arg)
                return err_no_arg(err, "deltabase");
        if (*atom->name == '*')
                oi_deref.info.delta_base_oid = &oi_deref.delta_base_oid;
        else
                oi.info.delta_base_oid = &oi.delta_base_oid;
        return 0;
}

static int body_atom_parser(struct ref_format *format UNUSED,
                            struct used_atom *atom,
                            const char *arg, struct strbuf *err)
{
        if (arg)
                return err_no_arg(err, "body");
        atom->u.contents.option = C_BODY_DEP;
        return 0;
}

static int subject_atom_parser(struct ref_format *format UNUSED,
                               struct used_atom *atom,
                               const char *arg, struct strbuf *err)
{
        if (!arg)
                atom->u.contents.option = C_SUB;
        else if (!strcmp(arg, "sanitize"))
                atom->u.contents.option = C_SUB_SANITIZE;
        else
                return err_bad_arg(err, "subject", arg);
        return 0;
}

static int parse_signature_option(const char *arg)
{
        if (!arg)
                return S_BARE;
        else if (!strcmp(arg, "signer"))
                return S_SIGNER;
        else if (!strcmp(arg, "grade"))
                return S_GRADE;
        else if (!strcmp(arg, "key"))
                return S_KEY;
        else if (!strcmp(arg, "fingerprint"))
                return S_FINGERPRINT;
        else if (!strcmp(arg, "primarykeyfingerprint"))
                return S_PRI_KEY_FP;
        else if (!strcmp(arg, "trustlevel"))
                return S_TRUST_LEVEL;
        return -1;
}

static int signature_atom_parser(struct ref_format *format UNUSED,
                                 struct used_atom *atom,
                                 const char *arg, struct strbuf *err)
{
        int opt = parse_signature_option(arg);
        if (opt < 0)
                return err_bad_arg(err, "signature", arg);
        atom->u.signature.option = opt;
        return 0;
}

static int trailers_atom_parser(struct ref_format *format, struct used_atom *atom,
                                const char *arg, struct strbuf *err)
{
        atom->u.contents.trailer_opts.no_divider = 1;

        if (arg) {
                const char *argbuf = xstrfmt("%s)", arg);
                char *invalid_arg = NULL;

                if (format_set_trailers_options(&atom->u.contents.trailer_opts,
                    &ref_trailer_buf.filter_list,
                    &ref_trailer_buf.sepbuf,
                    &ref_trailer_buf.kvsepbuf,
                    &argbuf, &invalid_arg)) {
                        if (!invalid_arg)
                                strbuf_addf(err, _("expected %%(trailers:key=<value>)"));
                        else
                                strbuf_addf(err, _("unknown %%(trailers) argument: %s"), invalid_arg);
                        free((char *)invalid_arg);
                        return -1;
                }
        }
        atom->u.contents.option = C_TRAILERS;
        return 0;
}

static int contents_atom_parser(struct ref_format *format, struct used_atom *atom,
                                const char *arg, struct strbuf *err)
{
        if (!arg)
                atom->u.contents.option = C_BARE;
        else if (!strcmp(arg, "body"))
                atom->u.contents.option = C_BODY;
        else if (!strcmp(arg, "size"))
                atom->u.contents.option = C_LENGTH;
        else if (!strcmp(arg, "signature"))
                atom->u.contents.option = C_SIG;
        else if (!strcmp(arg, "subject"))
                atom->u.contents.option = C_SUB;
        else if (!strcmp(arg, "trailers")) {
                if (trailers_atom_parser(format, atom, NULL, err))
                        return -1;
        } else if (skip_prefix(arg, "trailers:", &arg)) {
                if (trailers_atom_parser(format, atom, arg, err))
                        return -1;
        } else if (skip_prefix(arg, "lines=", &arg)) {
                atom->u.contents.option = C_LINES;
                if (strtoul_ui(arg, 10, &atom->u.contents.nlines))
                        return strbuf_addf_ret(err, -1, _("positive value expected contents:lines=%s"), arg);
        } else
                return err_bad_arg(err, "contents", arg);
        return 0;
}

static int describe_atom_option_parser(struct strvec *args, const char **arg,
                                       struct strbuf *err)
{
        const char *argval;
        size_t arglen = 0;
        int optval = 0;

        if (match_atom_bool_arg(*arg, "tags", arg, &optval)) {
                if (!optval)
                        strvec_push(args, "--no-tags");
                else
                        strvec_push(args, "--tags");
                return 1;
        }

        if (match_atom_arg_value(*arg, "abbrev", arg, &argval, &arglen)) {
                char *endptr;

                if (!arglen)
                        return strbuf_addf_ret(err, -1,
                                               _("argument expected for %s"),
                                               "describe:abbrev");
                if (strtol(argval, &endptr, 10) < 0)
                        return strbuf_addf_ret(err, -1,
                                               _("positive value expected %s=%s"),
                                               "describe:abbrev", argval);
                if (endptr - argval != arglen)
                        return strbuf_addf_ret(err, -1,
                                               _("cannot fully parse %s=%s"),
                                               "describe:abbrev", argval);

                strvec_pushf(args, "--abbrev=%.*s", (int)arglen, argval);
                return 1;
        }

        if (match_atom_arg_value(*arg, "match", arg, &argval, &arglen)) {
                if (!arglen)
                        return strbuf_addf_ret(err, -1,
                                               _("value expected %s="),
                                               "describe:match");

                strvec_pushf(args, "--match=%.*s", (int)arglen, argval);
                return 1;
        }

        if (match_atom_arg_value(*arg, "exclude", arg, &argval, &arglen)) {
                if (!arglen)
                        return strbuf_addf_ret(err, -1,
                                               _("value expected %s="),
                                               "describe:exclude");

                strvec_pushf(args, "--exclude=%.*s", (int)arglen, argval);
                return 1;
        }

        return 0;
}

static int describe_atom_parser(struct ref_format *format UNUSED,
                                struct used_atom *atom,
                                const char *arg, struct strbuf *err)
{
        struct strvec args = STRVEC_INIT;

        for (;;) {
                int found = 0;
                const char *bad_arg = arg;

                if (!arg || !*arg)
                        break;

                found = describe_atom_option_parser(&args, &arg, err);
                if (found < 0)
                        return found;
                if (!found)
                        return err_bad_arg(err, "describe", bad_arg);
        }
        atom->u.describe_args = strvec_detach(&args);
        return 0;
}

static int raw_atom_parser(struct ref_format *format UNUSED,
                           struct used_atom *atom,
                           const char *arg, struct strbuf *err)
{
        if (!arg)
                atom->u.raw_data.option = RAW_BARE;
        else if (!strcmp(arg, "size"))
                atom->u.raw_data.option = RAW_LENGTH;
        else
                return err_bad_arg(err, "raw", arg);
        return 0;
}

static int oid_atom_parser(struct ref_format *format UNUSED,
                           struct used_atom *atom,
                           const char *arg, struct strbuf *err)
{
        if (!arg)
                atom->u.oid.option = O_FULL;
        else if (!strcmp(arg, "short"))
                atom->u.oid.option = O_SHORT;
        else if (skip_prefix(arg, "short=", &arg)) {
                atom->u.oid.option = O_LENGTH;
                if (strtoul_ui(arg, 10, &atom->u.oid.length) ||
                    atom->u.oid.length == 0)
                        return strbuf_addf_ret(err, -1, _("positive value expected '%s' in %%(%s)"), arg, atom->name);
                if (atom->u.oid.length < MINIMUM_ABBREV)
                        atom->u.oid.length = MINIMUM_ABBREV;
        } else
                return err_bad_arg(err, atom->name, arg);
        return 0;
}

static int person_email_atom_parser(struct ref_format *format UNUSED,
                                    struct used_atom *atom,
                                    const char *arg, struct strbuf *err)
{
        if (!arg)
                atom->u.email_option.option = EO_RAW;
        else if (!strcmp(arg, "trim"))
                atom->u.email_option.option = EO_TRIM;
        else if (!strcmp(arg, "localpart"))
                atom->u.email_option.option = EO_LOCALPART;
        else
                return err_bad_arg(err, atom->name, arg);
        return 0;
}

static int refname_atom_parser(struct ref_format *format UNUSED,
                               struct used_atom *atom,
                               const char *arg, struct strbuf *err)
{
        return refname_atom_parser_internal(&atom->u.refname, arg, atom->name, err);
}

static align_type parse_align_position(const char *s)
{
        if (!strcmp(s, "right"))
                return ALIGN_RIGHT;
        else if (!strcmp(s, "middle"))
                return ALIGN_MIDDLE;
        else if (!strcmp(s, "left"))
                return ALIGN_LEFT;
        return -1;
}

static int align_atom_parser(struct ref_format *format UNUSED,
                             struct used_atom *atom,
                             const char *arg, struct strbuf *err)
{
        struct align *align = &atom->u.align;
        struct string_list params = STRING_LIST_INIT_DUP;
        int i;
        unsigned int width = ~0U;

        if (!arg)
                return strbuf_addf_ret(err, -1, _("expected format: %%(align:<width>,<position>)"));

        align->position = ALIGN_LEFT;

        string_list_split(&params, arg, ',', -1);
        for (i = 0; i < params.nr; i++) {
                const char *s = params.items[i].string;
                int position;

                if (skip_prefix(s, "position=", &s)) {
                        position = parse_align_position(s);
                        if (position < 0) {
                                strbuf_addf(err, _("unrecognized position:%s"), s);
                                string_list_clear(&params, 0);
                                return -1;
                        }
                        align->position = position;
                } else if (skip_prefix(s, "width=", &s)) {
                        if (strtoul_ui(s, 10, &width)) {
                                strbuf_addf(err, _("unrecognized width:%s"), s);
                                string_list_clear(&params, 0);
                                return -1;
                        }
                } else if (!strtoul_ui(s, 10, &width))
                        ;
                else if ((position = parse_align_position(s)) >= 0)
                        align->position = position;
                else {
                        strbuf_addf(err, _("unrecognized %%(%s) argument: %s"), "align", s);
                        string_list_clear(&params, 0);
                        return -1;
                }
        }

        if (width == ~0U) {
                string_list_clear(&params, 0);
                return strbuf_addf_ret(err, -1, _("positive width expected with the %%(align) atom"));
        }
        align->width = width;
        string_list_clear(&params, 0);
        return 0;
}

static int if_atom_parser(struct ref_format *format UNUSED,
                          struct used_atom *atom,
                          const char *arg, struct strbuf *err)
{
        if (!arg) {
                atom->u.if_then_else.cmp_status = COMPARE_NONE;
                return 0;
        } else if (skip_prefix(arg, "equals=", &atom->u.if_then_else.str)) {
                atom->u.if_then_else.cmp_status = COMPARE_EQUAL;
        } else if (skip_prefix(arg, "notequals=", &atom->u.if_then_else.str)) {
                atom->u.if_then_else.cmp_status = COMPARE_UNEQUAL;
        } else
                return err_bad_arg(err, "if", arg);
        return 0;
}

static int rest_atom_parser(struct ref_format *format,
                            struct used_atom *atom UNUSED,
                            const char *arg, struct strbuf *err)
{
        if (arg)
                return err_no_arg(err, "rest");
        return 0;
}

static int ahead_behind_atom_parser(struct ref_format *format, struct used_atom *atom,
                                    const char *arg, struct strbuf *err)
{
        struct string_list_item *item;

        if (!arg)
                return strbuf_addf_ret(err, -1, _("expected format: %%(ahead-behind:<committish>)"));

        item = string_list_append(&format->bases, arg);
        item->util = lookup_commit_reference_by_name(arg);
        if (!item->util)
                die("failed to find '%s'", arg);

        return 0;
}

static int head_atom_parser(struct ref_format *format UNUSED,
                            struct used_atom *atom,
                            const char *arg, struct strbuf *err)
{
        if (arg)
                return err_no_arg(err, "HEAD");
        atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, NULL, NULL);
        return 0;
}

static struct {
        const char *name;
        info_source source;
        cmp_type cmp_type;
        int (*parser)(struct ref_format *format, struct used_atom *atom,
                      const char *arg, struct strbuf *err);
} valid_atom[] = {
        [ATOM_REFNAME] = { "refname", SOURCE_NONE, FIELD_STR, refname_atom_parser },
        [ATOM_OBJECTTYPE] = { "objecttype", SOURCE_OTHER, FIELD_STR, objecttype_atom_parser },
        [ATOM_OBJECTSIZE] = { "objectsize", SOURCE_OTHER, FIELD_ULONG, objectsize_atom_parser },
        [ATOM_OBJECTNAME] = { "objectname", SOURCE_OTHER, FIELD_STR, oid_atom_parser },
        [ATOM_DELTABASE] = { "deltabase", SOURCE_OTHER, FIELD_STR, deltabase_atom_parser },
        [ATOM_TREE] = { "tree", SOURCE_OBJ, FIELD_STR, oid_atom_parser },
        [ATOM_PARENT] = { "parent", SOURCE_OBJ, FIELD_STR, oid_atom_parser },
        [ATOM_NUMPARENT] = { "numparent", SOURCE_OBJ, FIELD_ULONG },
        [ATOM_OBJECT] = { "object", SOURCE_OBJ },
        [ATOM_TYPE] = { "type", SOURCE_OBJ },
        [ATOM_TAG] = { "tag", SOURCE_OBJ },
        [ATOM_AUTHOR] = { "author", SOURCE_OBJ },
        [ATOM_AUTHORNAME] = { "authorname", SOURCE_OBJ },
        [ATOM_AUTHOREMAIL] = { "authoremail", SOURCE_OBJ, FIELD_STR, person_email_atom_parser },
        [ATOM_AUTHORDATE] = { "authordate", SOURCE_OBJ, FIELD_TIME },
        [ATOM_COMMITTER] = { "committer", SOURCE_OBJ },
        [ATOM_COMMITTERNAME] = { "committername", SOURCE_OBJ },
        [ATOM_COMMITTEREMAIL] = { "committeremail", SOURCE_OBJ, FIELD_STR, person_email_atom_parser },
        [ATOM_COMMITTERDATE] = { "committerdate", SOURCE_OBJ, FIELD_TIME },
        [ATOM_TAGGER] = { "tagger", SOURCE_OBJ },
        [ATOM_TAGGERNAME] = { "taggername", SOURCE_OBJ },
        [ATOM_TAGGEREMAIL] = { "taggeremail", SOURCE_OBJ, FIELD_STR, person_email_atom_parser },
        [ATOM_TAGGERDATE] = { "taggerdate", SOURCE_OBJ, FIELD_TIME },
        [ATOM_CREATOR] = { "creator", SOURCE_OBJ },
        [ATOM_CREATORDATE] = { "creatordate", SOURCE_OBJ, FIELD_TIME },
        [ATOM_DESCRIBE] = { "describe", SOURCE_OBJ, FIELD_STR, describe_atom_parser },
        [ATOM_SUBJECT] = { "subject", SOURCE_OBJ, FIELD_STR, subject_atom_parser },
        [ATOM_BODY] = { "body", SOURCE_OBJ, FIELD_STR, body_atom_parser },
        [ATOM_TRAILERS] = { "trailers", SOURCE_OBJ, FIELD_STR, trailers_atom_parser },
        [ATOM_CONTENTS] = { "contents", SOURCE_OBJ, FIELD_STR, contents_atom_parser },
        [ATOM_SIGNATURE] = { "signature", SOURCE_OBJ, FIELD_STR, signature_atom_parser },
        [ATOM_RAW] = { "raw", SOURCE_OBJ, FIELD_STR, raw_atom_parser },
        [ATOM_UPSTREAM] = { "upstream", SOURCE_NONE, FIELD_STR, remote_ref_atom_parser },
        [ATOM_PUSH] = { "push", SOURCE_NONE, FIELD_STR, remote_ref_atom_parser },
        [ATOM_SYMREF] = { "symref", SOURCE_NONE, FIELD_STR, refname_atom_parser },
        [ATOM_FLAG] = { "flag", SOURCE_NONE },
        [ATOM_HEAD] = { "HEAD", SOURCE_NONE, FIELD_STR, head_atom_parser },
        [ATOM_COLOR] = { "color", SOURCE_NONE, FIELD_STR, color_atom_parser },
        [ATOM_WORKTREEPATH] = { "worktreepath", SOURCE_NONE },
        [ATOM_ALIGN] = { "align", SOURCE_NONE, FIELD_STR, align_atom_parser },
        [ATOM_END] = { "end", SOURCE_NONE },
        [ATOM_IF] = { "if", SOURCE_NONE, FIELD_STR, if_atom_parser },
        [ATOM_THEN] = { "then", SOURCE_NONE },
        [ATOM_ELSE] = { "else", SOURCE_NONE },
        [ATOM_REST] = { "rest", SOURCE_NONE, FIELD_STR, rest_atom_parser },
        [ATOM_AHEADBEHIND] = { "ahead-behind", SOURCE_OTHER, FIELD_STR, ahead_behind_atom_parser },
        /*
         * Please update $__git_ref_fieldlist in git-completion.bash
         * when you add new atoms
         */
};

#define REF_FORMATTING_STATE_INIT  { 0 }

struct ref_formatting_stack {
        struct ref_formatting_stack *prev;
        struct strbuf output;
        void (*at_end)(struct ref_formatting_stack **stack);
        void *at_end_data;
};

struct ref_formatting_state {
        int quote_style;
        struct ref_formatting_stack *stack;
};

struct atom_value {
        const char *s;
        ssize_t s_size;
        int (*handler)(struct atom_value *atomv, struct ref_formatting_state *state,
                       struct strbuf *err);
        uintmax_t value; /* used for sorting when not FIELD_STR */
        struct used_atom *atom;
};

#define ATOM_SIZE_UNSPECIFIED (-1)

#define ATOM_VALUE_INIT { \
        .s_size = ATOM_SIZE_UNSPECIFIED \
}

/*
 * Used to parse format string and sort specifiers
 */
static int parse_ref_filter_atom(struct ref_format *format,
                                 const char *atom, const char *ep,
                                 struct strbuf *err)
{
        const char *sp;
        const char *arg;
        int i, at, atom_len;

        sp = atom;
        if (*sp == '*' && sp < ep)
                sp++; /* deref */
        if (ep <= sp)
                return strbuf_addf_ret(err, -1, _("malformed field name: %.*s"),
                                       (int)(ep-atom), atom);

        /*
         * If the atom name has a colon, strip it and everything after
         * it off - it specifies the format for this entry, and
         * shouldn't be used for checking against the valid_atom
         * table.
         */
        arg = memchr(sp, ':', ep - sp);
        atom_len = (arg ? arg : ep) - sp;

        /* Do we have the atom already used elsewhere? */
        for (i = 0; i < used_atom_cnt; i++) {
                int len = strlen(used_atom[i].name);
                if (len == ep - atom && !memcmp(used_atom[i].name, atom, len))
                        return i;
        }

        /* Is the atom a valid one? */
        for (i = 0; i < ARRAY_SIZE(valid_atom); i++) {
                int len = strlen(valid_atom[i].name);
                if (len == atom_len && !memcmp(valid_atom[i].name, sp, len))
                        break;
        }

        if (ARRAY_SIZE(valid_atom) <= i)
                return strbuf_addf_ret(err, -1, _("unknown field name: %.*s"),
                                       (int)(ep-atom), atom);
        if (valid_atom[i].source != SOURCE_NONE && !have_git_dir())
                return strbuf_addf_ret(err, -1,
                                       _("not a git repository, but the field '%.*s' requires access to object data"),
                                       (int)(ep-atom), atom);

        /* Add it in, including the deref prefix */
        at = used_atom_cnt;
        used_atom_cnt++;
        REALLOC_ARRAY(used_atom, used_atom_cnt);
        used_atom[at].atom_type = i;
        used_atom[at].name = xmemdupz(atom, ep - atom);
        used_atom[at].type = valid_atom[i].cmp_type;
        used_atom[at].source = valid_atom[i].source;
        if (used_atom[at].source == SOURCE_OBJ) {
                if (*atom == '*')
                        oi_deref.info.contentp = &oi_deref.content;
                else
                        oi.info.contentp = &oi.content;
        }
        if (arg) {
                arg = used_atom[at].name + (arg - atom) + 1;
                if (!*arg) {
                        /*
                         * Treat empty sub-arguments list as NULL (i.e.,
                         * "%(atom:)" is equivalent to "%(atom)").
                         */
                        arg = NULL;
                }
        }
        memset(&used_atom[at].u, 0, sizeof(used_atom[at].u));
        if (valid_atom[i].parser && valid_atom[i].parser(format, &used_atom[at], arg, err))
                return -1;
        if (*atom == '*')
                need_tagged = 1;
        if (i == ATOM_SYMREF)
                need_symref = 1;
        return at;
}

static void quote_formatting(struct strbuf *s, const char *str, ssize_t len, int quote_style)
{
        switch (quote_style) {
        case QUOTE_NONE:
                if (len < 0)
                        strbuf_addstr(s, str);
                else
                        strbuf_add(s, str, len);
                break;
        case QUOTE_SHELL:
                sq_quote_buf(s, str);
                break;
        case QUOTE_PERL:
                if (len < 0)
                        perl_quote_buf(s, str);
                else
                        perl_quote_buf_with_len(s, str, len);
                break;
        case QUOTE_PYTHON:
                python_quote_buf(s, str);
                break;
        case QUOTE_TCL:
                tcl_quote_buf(s, str);
                break;
        }
}

static int append_atom(struct atom_value *v, struct ref_formatting_state *state,
                       struct strbuf *err UNUSED)
{
        /*
         * Quote formatting is only done when the stack has a single
         * element. Otherwise quote formatting is done on the
         * element's entire output strbuf when the %(end) atom is
         * encountered.
         */
        if (!state->stack->prev)
                quote_formatting(&state->stack->output, v->s, v->s_size, state->quote_style);
        else if (v->s_size < 0)
                strbuf_addstr(&state->stack->output, v->s);
        else
                strbuf_add(&state->stack->output, v->s, v->s_size);
        return 0;
}

static void push_stack_element(struct ref_formatting_stack **stack)
{
        struct ref_formatting_stack *s = xcalloc(1, sizeof(struct ref_formatting_stack));

        strbuf_init(&s->output, 0);
        s->prev = *stack;
        *stack = s;
}

static void pop_stack_element(struct ref_formatting_stack **stack)
{
        struct ref_formatting_stack *current = *stack;
        struct ref_formatting_stack *prev = current->prev;

        if (prev)
                strbuf_addbuf(&prev->output, &current->output);
        strbuf_release(&current->output);
        free(current);
        *stack = prev;
}

static void end_align_handler(struct ref_formatting_stack **stack)
{
        struct ref_formatting_stack *cur = *stack;
        struct align *align = (struct align *)cur->at_end_data;
        struct strbuf s = STRBUF_INIT;

        strbuf_utf8_align(&s, align->position, align->width, cur->output.buf);
        strbuf_swap(&cur->output, &s);
        strbuf_release(&s);
}

static int align_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
                              struct strbuf *err UNUSED)
{
        struct ref_formatting_stack *new_stack;

        push_stack_element(&state->stack);
        new_stack = state->stack;
        new_stack->at_end = end_align_handler;
        new_stack->at_end_data = &atomv->atom->u.align;
        return 0;
}

static void if_then_else_handler(struct ref_formatting_stack **stack)
{
        struct ref_formatting_stack *cur = *stack;
        struct ref_formatting_stack *prev = cur->prev;
        struct if_then_else *if_then_else = (struct if_then_else *)cur->at_end_data;

        if (!if_then_else->then_atom_seen)
                die(_("format: %%(%s) atom used without a %%(%s) atom"), "if", "then");

        if (if_then_else->else_atom_seen) {
                /*
                 * There is an %(else) atom: we need to drop one state from the
                 * stack, either the %(else) branch if the condition is satisfied, or
                 * the %(then) branch if it isn't.
                 */
                if (if_then_else->condition_satisfied) {
                        strbuf_reset(&cur->output);
                        pop_stack_element(&cur);
                } else {
                        strbuf_swap(&cur->output, &prev->output);
                        strbuf_reset(&cur->output);
                        pop_stack_element(&cur);
                }
        } else if (!if_then_else->condition_satisfied) {
                /*
                 * No %(else) atom: just drop the %(then) branch if the
                 * condition is not satisfied.
                 */
                strbuf_reset(&cur->output);
        }

        *stack = cur;
        free(if_then_else);
}

static int if_atom_handler(struct atom_value *atomv, struct ref_formatting_state *state,
                           struct strbuf *err UNUSED)
{
        struct ref_formatting_stack *new_stack;
        struct if_then_else *if_then_else = xcalloc(1,
                                                    sizeof(struct if_then_else));

        if_then_else->str = atomv->atom->u.if_then_else.str;
        if_then_else->cmp_status = atomv->atom->u.if_then_else.cmp_status;

        push_stack_element(&state->stack);
        new_stack = state->stack;
        new_stack->at_end = if_then_else_handler;
        new_stack->at_end_data = if_then_else;
        return 0;
}

static int is_empty(struct strbuf *buf)
{
        const char *cur = buf->buf;
        const char *end = buf->buf + buf->len;

        while (cur != end && (isspace(*cur)))
                cur++;

        return cur == end;
 }

static int then_atom_handler(struct atom_value *atomv UNUSED,
                             struct ref_formatting_state *state,
                             struct strbuf *err)
{
        struct ref_formatting_stack *cur = state->stack;
        struct if_then_else *if_then_else = NULL;
        size_t str_len = 0;

        if (cur->at_end == if_then_else_handler)
                if_then_else = (struct if_then_else *)cur->at_end_data;
        if (!if_then_else)
                return strbuf_addf_ret(err, -1, _("format: %%(%s) atom used without a %%(%s) atom"), "then", "if");
        if (if_then_else->then_atom_seen)
                return strbuf_addf_ret(err, -1, _("format: %%(then) atom used more than once"));
        if (if_then_else->else_atom_seen)
                return strbuf_addf_ret(err, -1, _("format: %%(then) atom used after %%(else)"));
        if_then_else->then_atom_seen = 1;
        if (if_then_else->str)
                str_len = strlen(if_then_else->str);
        /*
         * If the 'equals' or 'notequals' attribute is used then
         * perform the required comparison. If not, only non-empty
         * strings satisfy the 'if' condition.
         */
        if (if_then_else->cmp_status == COMPARE_EQUAL) {
                if (str_len == cur->output.len &&
                    !memcmp(if_then_else->str, cur->output.buf, cur->output.len))
                        if_then_else->condition_satisfied = 1;
        } else if (if_then_else->cmp_status == COMPARE_UNEQUAL) {
                if (str_len != cur->output.len ||
                    memcmp(if_then_else->str, cur->output.buf, cur->output.len))
                        if_then_else->condition_satisfied = 1;
        } else if (cur->output.len && !is_empty(&cur->output))
                if_then_else->condition_satisfied = 1;
        strbuf_reset(&cur->output);
        return 0;
}

static int else_atom_handler(struct atom_value *atomv UNUSED,
                             struct ref_formatting_state *state,
                             struct strbuf *err)
{
        struct ref_formatting_stack *prev = state->stack;
        struct if_then_else *if_then_else = NULL;

        if (prev->at_end == if_then_else_handler)
                if_then_else = (struct if_then_else *)prev->at_end_data;
        if (!if_then_else)
                return strbuf_addf_ret(err, -1, _("format: %%(%s) atom used without a %%(%s) atom"), "else", "if");
        if (!if_then_else->then_atom_seen)
                return strbuf_addf_ret(err, -1, _("format: %%(%s) atom used without a %%(%s) atom"), "else", "then");
        if (if_then_else->else_atom_seen)
                return strbuf_addf_ret(err, -1, _("format: %%(else) atom used more than once"));
        if_then_else->else_atom_seen = 1;
        push_stack_element(&state->stack);
        state->stack->at_end_data = prev->at_end_data;
        state->stack->at_end = prev->at_end;
        return 0;
}

static int end_atom_handler(struct atom_value *atomv UNUSED,
                            struct ref_formatting_state *state,
                            struct strbuf *err)
{
        struct ref_formatting_stack *current = state->stack;
        struct strbuf s = STRBUF_INIT;

        if (!current->at_end)
                return strbuf_addf_ret(err, -1, _("format: %%(end) atom used without corresponding atom"));
        current->at_end(&state->stack);

        /*  Stack may have been popped within at_end(), hence reset the current pointer */
        current = state->stack;

        /*
         * Perform quote formatting when the stack element is that of
         * a supporting atom. If nested then perform quote formatting
         * only on the topmost supporting atom.
         */
        if (!current->prev->prev) {
                quote_formatting(&s, current->output.buf, current->output.len, state->quote_style);
                strbuf_swap(&current->output, &s);
        }
        strbuf_release(&s);
        pop_stack_element(&state->stack);
        return 0;
}

/*
 * In a format string, find the next occurrence of %(atom).
 */
static const char *find_next(const char *cp)
{
        while (*cp) {
                if (*cp == '%') {
                        /*
                         * %( is the start of an atom;
                         * %% is a quoted per-cent.
                         */
                        if (cp[1] == '(')
                                return cp;
                        else if (cp[1] == '%')
                                cp++; /* skip over two % */
                        /* otherwise this is a singleton, literal % */
                }
                cp++;
        }
        return NULL;
}

static int reject_atom(enum atom_type atom_type)
{
        return atom_type == ATOM_REST;
}

/*
 * Make sure the format string is well formed, and parse out
 * the used atoms.
 */
int verify_ref_format(struct ref_format *format)
{
        const char *cp, *sp;

        format->need_color_reset_at_eol = 0;
        for (cp = format->format; *cp && (sp = find_next(cp)); ) {
                struct strbuf err = STRBUF_INIT;
                const char *color, *ep = strchr(sp, ')');
                int at;

                if (!ep)
                        return error(_("malformed format string %s"), sp);
                /* sp points at "%(" and ep points at the closing ")" */
                at = parse_ref_filter_atom(format, sp + 2, ep, &err);
                if (at < 0)
                        die("%s", err.buf);
                if (reject_atom(used_atom[at].atom_type))
                        die(_("this command reject atom %%(%.*s)"), (int)(ep - sp - 2), sp + 2);

                if ((format->quote_style == QUOTE_PYTHON ||
                     format->quote_style == QUOTE_SHELL ||
                     format->quote_style == QUOTE_TCL) &&
                     used_atom[at].atom_type == ATOM_RAW &&
                     used_atom[at].u.raw_data.option == RAW_BARE)
                        die(_("--format=%.*s cannot be used with "
                              "--python, --shell, --tcl"), (int)(ep - sp - 2), sp + 2);
                cp = ep + 1;

                if (skip_prefix(used_atom[at].name, "color:", &color))
                        format->need_color_reset_at_eol = !!strcmp(color, "reset");
                strbuf_release(&err);
        }
        if (format->need_color_reset_at_eol && !want_color(format->use_color))
                format->need_color_reset_at_eol = 0;
        return 0;
}

static const char *do_grab_oid(const char *field, const struct object_id *oid,
                               struct used_atom *atom)
{
        switch (atom->u.oid.option) {
        case O_FULL:
                return oid_to_hex(oid);
        case O_LENGTH:
                return repo_find_unique_abbrev(the_repository, oid,
                                               atom->u.oid.length);
        case O_SHORT:
                return repo_find_unique_abbrev(the_repository, oid,
                                               DEFAULT_ABBREV);
        default:
                BUG("unknown %%(%s) option", field);
        }
}

static int grab_oid(const char *name, const char *field, const struct object_id *oid,
                    struct atom_value *v, struct used_atom *atom)
{
        if (starts_with(name, field)) {
                v->s = xstrdup(do_grab_oid(field, oid, atom));
                return 1;
        }
        return 0;
}

/* See grab_values */
static void grab_common_values(struct atom_value *val, int deref, struct expand_data *oi)
{
        int i;

        for (i = 0; i < used_atom_cnt; i++) {
                const char *name = used_atom[i].name;
                enum atom_type atom_type = used_atom[i].atom_type;
                struct atom_value *v = &val[i];
                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;
                if (atom_type == ATOM_OBJECTTYPE)
                        v->s = xstrdup(type_name(oi->type));
                else if (atom_type == ATOM_OBJECTSIZE) {
                        if (used_atom[i].u.objectsize.option == O_SIZE_DISK) {
                                v->value = oi->disk_size;
                                v->s = xstrfmt("%"PRIuMAX, (uintmax_t)oi->disk_size);
                        } else if (used_atom[i].u.objectsize.option == O_SIZE) {
                                v->value = oi->size;
                                v->s = xstrfmt("%"PRIuMAX , (uintmax_t)oi->size);
                        }
                } else if (atom_type == ATOM_DELTABASE)
                        v->s = xstrdup(oid_to_hex(&oi->delta_base_oid));
                else if (atom_type == ATOM_OBJECTNAME && deref)
                        grab_oid(name, "objectname", &oi->oid, v, &used_atom[i]);
        }
}

/* See grab_values */
static void grab_tag_values(struct atom_value *val, int deref, struct object *obj)
{
        int i;
        struct tag *tag = (struct tag *) obj;

        for (i = 0; i < used_atom_cnt; i++) {
                const char *name = used_atom[i].name;
                enum atom_type atom_type = used_atom[i].atom_type;
                struct atom_value *v = &val[i];
                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;
                if (atom_type == ATOM_TAG)
                        v->s = xstrdup(tag->tag);
                else if (atom_type == ATOM_TYPE && tag->tagged)
                        v->s = xstrdup(type_name(tag->tagged->type));
                else if (atom_type == ATOM_OBJECT && tag->tagged)
                        v->s = xstrdup(oid_to_hex(&tag->tagged->oid));
        }
}

/* See grab_values */
static void grab_commit_values(struct atom_value *val, int deref, struct object *obj)
{
        int i;
        struct commit *commit = (struct commit *) obj;

        for (i = 0; i < used_atom_cnt; i++) {
                const char *name = used_atom[i].name;
                enum atom_type atom_type = used_atom[i].atom_type;
                struct atom_value *v = &val[i];
                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;
                if (atom_type == ATOM_TREE &&
                    grab_oid(name, "tree", get_commit_tree_oid(commit), v, &used_atom[i]))
                        continue;
                if (atom_type == ATOM_NUMPARENT) {
                        v->value = commit_list_count(commit->parents);
                        v->s = xstrfmt("%lu", (unsigned long)v->value);
                }
                else if (atom_type == ATOM_PARENT) {
                        struct commit_list *parents;
                        struct strbuf s = STRBUF_INIT;
                        for (parents = commit->parents; parents; parents = parents->next) {
                                struct object_id *oid = &parents->item->object.oid;
                                if (parents != commit->parents)
                                        strbuf_addch(&s, ' ');
                                strbuf_addstr(&s, do_grab_oid("parent", oid, &used_atom[i]));
                        }
                        v->s = strbuf_detach(&s, NULL);
                }
        }
}

static const char *find_wholine(const char *who, int wholen, const char *buf)
{
        const char *eol;
        while (*buf) {
                if (!strncmp(buf, who, wholen) &&
                    buf[wholen] == ' ')
                        return buf + wholen + 1;
                eol = strchr(buf, '\n');
                if (!eol)
                        return "";
                eol++;
                if (*eol == '\n')
                        return ""; /* end of header */
                buf = eol;
        }
        return "";
}

static const char *copy_line(const char *buf)
{
        const char *eol = strchrnul(buf, '\n');
        return xmemdupz(buf, eol - buf);
}

static const char *copy_name(const char *buf)
{
        const char *cp;
        for (cp = buf; *cp && *cp != '\n'; cp++) {
                if (starts_with(cp, " <"))
                        return xmemdupz(buf, cp - buf);
        }
        return xstrdup("");
}

static const char *copy_email(const char *buf, struct used_atom *atom)
{
        const char *email = strchr(buf, '<');
        const char *eoemail;
        if (!email)
                return xstrdup("");
        switch (atom->u.email_option.option) {
        case EO_RAW:
                eoemail = strchr(email, '>');
                if (eoemail)
                        eoemail++;
                break;
        case EO_TRIM:
                email++;
                eoemail = strchr(email, '>');
                break;
        case EO_LOCALPART:
                email++;
                eoemail = strchr(email, '@');
                if (!eoemail)
                        eoemail = strchr(email, '>');
                break;
        default:
                BUG("unknown email option");
        }

        if (!eoemail)
                return xstrdup("");
        return xmemdupz(email, eoemail - email);
}

static char *copy_subject(const char *buf, unsigned long len)
{
        struct strbuf sb = STRBUF_INIT;
        int i;

        for (i = 0; i < len; i++) {
                if (buf[i] == '\r' && i + 1 < len && buf[i + 1] == '\n')
                        continue; /* ignore CR in CRLF */

                if (buf[i] == '\n')
                        strbuf_addch(&sb, ' ');
                else
                        strbuf_addch(&sb, buf[i]);
        }
        return strbuf_detach(&sb, NULL);
}

static void grab_date(const char *buf, struct atom_value *v, const char *atomname)
{
        const char *eoemail = strstr(buf, "> ");
        char *zone;
        timestamp_t timestamp;
        long tz;
        struct date_mode date_mode = DATE_MODE_INIT;
        const char *formatp;

        /*
         * We got here because atomname ends in "date" or "date<something>";
         * it's not possible that <something> is not ":<format>" because
         * parse_ref_filter_atom() wouldn't have allowed it, so we can assume that no
         * ":" means no format is specified, and use the default.
         */
        formatp = strchr(atomname, ':');
        if (formatp) {
                formatp++;
                parse_date_format(formatp, &date_mode);
        }

        if (!eoemail)
                goto bad;
        timestamp = parse_timestamp(eoemail + 2, &zone, 10);
        if (timestamp == TIME_MAX)
                goto bad;
        tz = strtol(zone, NULL, 10);
        if ((tz == LONG_MIN || tz == LONG_MAX) && errno == ERANGE)
                goto bad;
        v->s = xstrdup(show_date(timestamp, tz, &date_mode));
        v->value = timestamp;
        date_mode_release(&date_mode);
        return;
 bad:
        v->s = xstrdup("");
        v->value = 0;
}

/* See grab_values */
static void grab_person(const char *who, struct atom_value *val, int deref, void *buf)
{
        int i;
        int wholen = strlen(who);
        const char *wholine = NULL;

        for (i = 0; i < used_atom_cnt; i++) {
                const char *name = used_atom[i].name;
                struct atom_value *v = &val[i];
                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;
                if (strncmp(who, name, wholen))
                        continue;
                if (name[wholen] != 0 &&
                    strcmp(name + wholen, "name") &&
                    !starts_with(name + wholen, "email") &&
                    !starts_with(name + wholen, "date"))
                        continue;
                if (!wholine)
                        wholine = find_wholine(who, wholen, buf);
                if (!wholine)
                        return; /* no point looking for it */
                if (name[wholen] == 0)
                        v->s = copy_line(wholine);
                else if (!strcmp(name + wholen, "name"))
                        v->s = copy_name(wholine);
                else if (starts_with(name + wholen, "email"))
                        v->s = copy_email(wholine, &used_atom[i]);
                else if (starts_with(name + wholen, "date"))
                        grab_date(wholine, v, name);
        }

        /*
         * For a tag or a commit object, if "creator" or "creatordate" is
         * requested, do something special.
         */
        if (strcmp(who, "tagger") && strcmp(who, "committer"))
                return; /* "author" for commit object is not wanted */
        if (!wholine)
                wholine = find_wholine(who, wholen, buf);
        if (!wholine)
                return;
        for (i = 0; i < used_atom_cnt; i++) {
                const char *name = used_atom[i].name;
                enum atom_type atom_type = used_atom[i].atom_type;
                struct atom_value *v = &val[i];
                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;

                if (atom_type == ATOM_CREATORDATE)
                        grab_date(wholine, v, name);
                else if (atom_type == ATOM_CREATOR)
                        v->s = copy_line(wholine);
        }
}

static void grab_signature(struct atom_value *val, int deref, struct object *obj)
{
        int i;
        struct commit *commit = (struct commit *) obj;
        struct signature_check sigc = { 0 };
        int signature_checked = 0;

        for (i = 0; i < used_atom_cnt; i++) {
                struct used_atom *atom = &used_atom[i];
                const char *name = atom->name;
                struct atom_value *v = &val[i];
                int opt;

                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;

                if (!skip_prefix(name, "signature", &name) ||
                    (*name && *name != ':'))
                        continue;
                if (!*name)
                        name = NULL;
                else
                        name++;

                opt = parse_signature_option(name);
                if (opt < 0)
                        continue;

                if (!signature_checked) {
                        check_commit_signature(commit, &sigc);
                        signature_checked = 1;
                }

                switch (opt) {
                case S_BARE:
                        v->s = xstrdup(sigc.output ? sigc.output: "");
                        break;
                case S_SIGNER:
                        v->s = xstrdup(sigc.signer ? sigc.signer : "");
                        break;
                case S_GRADE:
                        switch (sigc.result) {
                        case 'G':
                                switch (sigc.trust_level) {
                                case TRUST_UNDEFINED:
                                case TRUST_NEVER:
                                        v->s = xstrfmt("%c", (char)'U');
                                        break;
                                default:
                                        v->s = xstrfmt("%c", (char)'G');
                                        break;
                                }
                                break;
                        case 'B':
                        case 'E':
                        case 'N':
                        case 'X':
                        case 'Y':
                        case 'R':
                                v->s = xstrfmt("%c", (char)sigc.result);
                                break;
                        }
                        break;
                case S_KEY:
                        v->s = xstrdup(sigc.key ? sigc.key : "");
                        break;
                case S_FINGERPRINT:
                        v->s = xstrdup(sigc.fingerprint ?
                                       sigc.fingerprint : "");
                        break;
                case S_PRI_KEY_FP:
                        v->s = xstrdup(sigc.primary_key_fingerprint ?
                                       sigc.primary_key_fingerprint : "");
                        break;
                case S_TRUST_LEVEL:
                        v->s = xstrdup(gpg_trust_level_to_str(sigc.trust_level));
                        break;
                }
        }

        if (signature_checked)
                signature_check_clear(&sigc);
}

static void find_subpos(const char *buf,
                        const char **sub, size_t *sublen,
                        const char **body, size_t *bodylen,
                        size_t *nonsiglen,
                        const char **sig, size_t *siglen)
{
        struct strbuf payload = STRBUF_INIT;
        struct strbuf signature = STRBUF_INIT;
        const char *eol;
        const char *end = buf + strlen(buf);
        const char *sigstart;

        /* parse signature first; we might not even have a subject line */
        parse_signature(buf, end - buf, &payload, &signature);
        strbuf_release(&payload);

        /* skip past header until we hit empty line */
        while (*buf && *buf != '\n') {
                eol = strchrnul(buf, '\n');
                if (*eol)
                        eol++;
                buf = eol;
        }
        /* skip any empty lines */
        while (*buf == '\n')
                buf++;
        *sig = strbuf_detach(&signature, siglen);
        sigstart = buf + parse_signed_buffer(buf, strlen(buf));

        /* subject is first non-empty line */
        *sub = buf;
        /* subject goes to first empty line before signature begins */
        if ((eol = strstr(*sub, "\n\n")) ||
            (eol = strstr(*sub, "\r\n\r\n"))) {
                eol = eol < sigstart ? eol : sigstart;
        } else {
                /* treat whole message as subject */
                eol = sigstart;
        }
        buf = eol;
        *sublen = buf - *sub;
        /* drop trailing newline, if present */
        while (*sublen && ((*sub)[*sublen - 1] == '\n' ||
                           (*sub)[*sublen - 1] == '\r'))
                *sublen -= 1;

        /* skip any empty lines */
        while (*buf == '\n' || *buf == '\r')
                buf++;
        *body = buf;
        *bodylen = strlen(buf);
        *nonsiglen = sigstart - buf;
}

/*
 * If 'lines' is greater than 0, append that many lines from the given
 * 'buf' of length 'size' to the given strbuf.
 */
static void append_lines(struct strbuf *out, const char *buf, unsigned long size, int lines)
{
        int i;
        const char *sp, *eol;
        size_t len;

        sp = buf;

        for (i = 0; i < lines && sp < buf + size; i++) {
                if (i)
                        strbuf_addstr(out, "\n    ");
                eol = memchr(sp, '\n', size - (sp - buf));
                len = eol ? eol - sp : size - (sp - buf);
                strbuf_add(out, sp, len);
                if (!eol)
                        break;
                sp = eol + 1;
        }
}

static void grab_describe_values(struct atom_value *val, int deref,
                                 struct object *obj)
{
        struct commit *commit = (struct commit *)obj;
        int i;

        for (i = 0; i < used_atom_cnt; i++) {
                struct used_atom *atom = &used_atom[i];
                enum atom_type type = atom->atom_type;
                const char *name = atom->name;
                struct atom_value *v = &val[i];

                struct child_process cmd = CHILD_PROCESS_INIT;
                struct strbuf out = STRBUF_INIT;
                struct strbuf err = STRBUF_INIT;

                if (type != ATOM_DESCRIBE)
                        continue;

                if (!!deref != (*name == '*'))
                        continue;

                cmd.git_cmd = 1;
                strvec_push(&cmd.args, "describe");
                strvec_pushv(&cmd.args, atom->u.describe_args);
                strvec_push(&cmd.args, oid_to_hex(&commit->object.oid));
                if (pipe_command(&cmd, NULL, 0, &out, 0, &err, 0) < 0) {
                        error(_("failed to run 'describe'"));
                        v->s = xstrdup("");
                        continue;
                }
                strbuf_rtrim(&out);
                v->s = strbuf_detach(&out, NULL);

                strbuf_release(&err);
        }
}

/* See grab_values */
static void grab_sub_body_contents(struct atom_value *val, int deref, struct expand_data *data)
{
        int i;
        const char *subpos = NULL, *bodypos = NULL, *sigpos = NULL;
        size_t sublen = 0, bodylen = 0, nonsiglen = 0, siglen = 0;
        void *buf = data->content;

        for (i = 0; i < used_atom_cnt; i++) {
                struct used_atom *atom = &used_atom[i];
                const char *name = atom->name;
                struct atom_value *v = &val[i];
                enum atom_type atom_type = atom->atom_type;

                if (!!deref != (*name == '*'))
                        continue;
                if (deref)
                        name++;

                if (atom_type == ATOM_RAW) {
                        unsigned long buf_size = data->size;

                        if (atom->u.raw_data.option == RAW_BARE) {
                                v->s = xmemdupz(buf, buf_size);
                                v->s_size = buf_size;
                        } else if (atom->u.raw_data.option == RAW_LENGTH) {
                                v->s = xstrfmt("%"PRIuMAX, (uintmax_t)buf_size);
                        }
                        continue;
                }

                if ((data->type != OBJ_TAG &&
                     data->type != OBJ_COMMIT) ||
                    (strcmp(name, "body") &&
                     !starts_with(name, "subject") &&
                     !starts_with(name, "trailers") &&
                     !starts_with(name, "contents")))
                        continue;
                if (!subpos)
                        find_subpos(buf,
                                    &subpos, &sublen,
                                    &bodypos, &bodylen, &nonsiglen,
                                    &sigpos, &siglen);

                if (atom->u.contents.option == C_SUB)
                        v->s = copy_subject(subpos, sublen);
                else if (atom->u.contents.option == C_SUB_SANITIZE) {
                        struct strbuf sb = STRBUF_INIT;
                        format_sanitized_subject(&sb, subpos, sublen);
                        v->s = strbuf_detach(&sb, NULL);
                } else if (atom->u.contents.option == C_BODY_DEP)
                        v->s = xmemdupz(bodypos, bodylen);
                else if (atom->u.contents.option == C_LENGTH)
                        v->s = xstrfmt("%"PRIuMAX, (uintmax_t)strlen(subpos));
                else if (atom->u.contents.option == C_BODY)
                        v->s = xmemdupz(bodypos, nonsiglen);
                else if (atom->u.contents.option == C_SIG)
                        v->s = xmemdupz(sigpos, siglen);
                else if (atom->u.contents.option == C_LINES) {
                        struct strbuf s = STRBUF_INIT;
                        const char *contents_end = bodypos + nonsiglen;

                        /*  Size is the length of the message after removing the signature */
                        append_lines(&s, subpos, contents_end - subpos, atom->u.contents.nlines);
                        v->s = strbuf_detach(&s, NULL);
                } else if (atom->u.contents.option == C_TRAILERS) {
                        struct strbuf s = STRBUF_INIT;

                        /* Format the trailer info according to the trailer_opts given */
                        format_trailers_from_commit(&s, subpos, &atom->u.contents.trailer_opts);

                        v->s = strbuf_detach(&s, NULL);
                } else if (atom->u.contents.option == C_BARE)
                        v->s = xstrdup(subpos);

        }
        free((void *)sigpos);
}

/*
 * We want to have empty print-string for field requests
 * that do not apply (e.g. "authordate" for a tag object)
 */
static void fill_missing_values(struct atom_value *val)
{
        int i;
        for (i = 0; i < used_atom_cnt; i++) {
                struct atom_value *v = &val[i];
                if (!v->s)
                        v->s = xstrdup("");
        }
}

/*
 * val is a list of atom_value to hold returned values.  Extract
 * the values for atoms in used_atom array out of (obj, buf, sz).
 * when deref is false, (obj, buf, sz) is the object that is
 * pointed at by the ref itself; otherwise it is the object the
 * ref (which is a tag) refers to.
 */
static void grab_values(struct atom_value *val, int deref, struct object *obj, struct expand_data *data)
{
        void *buf = data->content;

        switch (obj->type) {
        case OBJ_TAG:
                grab_tag_values(val, deref, obj);
                grab_sub_body_contents(val, deref, data);
                grab_person("tagger", val, deref, buf);
                grab_describe_values(val, deref, obj);
                break;
        case OBJ_COMMIT:
                grab_commit_values(val, deref, obj);
                grab_sub_body_contents(val, deref, data);
                grab_person("author", val, deref, buf);
                grab_person("committer", val, deref, buf);
                grab_signature(val, deref, obj);
                grab_describe_values(val, deref, obj);
                break;
        case OBJ_TREE:
                /* grab_tree_values(val, deref, obj, buf, sz); */
                grab_sub_body_contents(val, deref, data);
                break;
        case OBJ_BLOB:
                /* grab_blob_values(val, deref, obj, buf, sz); */
                grab_sub_body_contents(val, deref, data);
                break;
        default:
                die("Eh?  Object of type %d?", obj->type);
        }
}

static inline char *copy_advance(char *dst, const char *src)
{
        while (*src)
                *dst++ = *src++;
        return dst;
}

static const char *lstrip_ref_components(const char *refname, int len)
{
        long remaining = len;
        const char *start = xstrdup(refname);
        const char *to_free = start;

        if (len < 0) {
                int i;
                const char *p = refname;

                /* Find total no of '/' separated path-components */
                for (i = 0; p[i]; p[i] == '/' ? i++ : *p++)
                        ;
                /*
                 * The number of components we need to strip is now
                 * the total minus the components to be left (Plus one
                 * because we count the number of '/', but the number
                 * of components is one more than the no of '/').
                 */
                remaining = i + len + 1;
        }

        while (remaining > 0) {
                switch (*start++) {
                case '\0':
                        free((char *)to_free);
                        return xstrdup("");
                case '/':
                        remaining--;
                        break;
                }
        }

        start = xstrdup(start);
        free((char *)to_free);
        return start;
}

static const char *rstrip_ref_components(const char *refname, int len)
{
        long remaining = len;
        const char *start = xstrdup(refname);
        const char *to_free = start;

        if (len < 0) {
                int i;
                const char *p = refname;

                /* Find total no of '/' separated path-components */
                for (i = 0; p[i]; p[i] == '/' ? i++ : *p++)
                        ;
                /*
                 * The number of components we need to strip is now
                 * the total minus the components to be left (Plus one
                 * because we count the number of '/', but the number
                 * of components is one more than the no of '/').
                 */
                remaining = i + len + 1;
        }

        while (remaining-- > 0) {
                char *p = strrchr(start, '/');
                if (!p) {
                        free((char *)to_free);
                        return xstrdup("");
                } else
                        p[0] = '\0';
        }
        return start;
}

static const char *show_ref(struct refname_atom *atom, const char *refname)
{
        if (atom->option == R_SHORT)
                return shorten_unambiguous_ref(refname, warn_ambiguous_refs);
        else if (atom->option == R_LSTRIP)
                return lstrip_ref_components(refname, atom->lstrip);
        else if (atom->option == R_RSTRIP)
                return rstrip_ref_components(refname, atom->rstrip);
        else
                return xstrdup(refname);
}

static void fill_remote_ref_details(struct used_atom *atom, const char *refname,
                                    struct branch *branch, const char **s)
{
        int num_ours, num_theirs;
        if (atom->u.remote_ref.option == RR_REF)
                *s = show_ref(&atom->u.remote_ref.refname, refname);
        else if (atom->u.remote_ref.option == RR_TRACK) {
                if (stat_tracking_info(branch, &num_ours, &num_theirs,
                                       NULL, atom->u.remote_ref.push,
                                       AHEAD_BEHIND_FULL) < 0) {
                        *s = xstrdup(msgs.gone);
                } else if (!num_ours && !num_theirs)
                        *s = xstrdup("");
                else if (!num_ours)
                        *s = xstrfmt(msgs.behind, num_theirs);
                else if (!num_theirs)
                        *s = xstrfmt(msgs.ahead, num_ours);
                else
                        *s = xstrfmt(msgs.ahead_behind,
                                     num_ours, num_theirs);
                if (!atom->u.remote_ref.nobracket && *s[0]) {
                        const char *to_free = *s;
                        *s = xstrfmt("[%s]", *s);
                        free((void *)to_free);
                }
        } else if (atom->u.remote_ref.option == RR_TRACKSHORT) {
                if (stat_tracking_info(branch, &num_ours, &num_theirs,
                                       NULL, atom->u.remote_ref.push,
                                       AHEAD_BEHIND_FULL) < 0) {
                        *s = xstrdup("");
                        return;
                }
                if (!num_ours && !num_theirs)
                        *s = xstrdup("=");
                else if (!num_ours)
                        *s = xstrdup("<");
                else if (!num_theirs)
                        *s = xstrdup(">");
                else
                        *s = xstrdup("<>");
        } else if (atom->u.remote_ref.option == RR_REMOTE_NAME) {
                int explicit;
                const char *remote = atom->u.remote_ref.push ?
                        pushremote_for_branch(branch, &explicit) :
                        remote_for_branch(branch, &explicit);
                *s = xstrdup(explicit ? remote : "");
        } else if (atom->u.remote_ref.option == RR_REMOTE_REF) {
                const char *merge;

                merge = remote_ref_for_branch(branch, atom->u.remote_ref.push);
                *s = xstrdup(merge ? merge : "");
        } else
                BUG("unhandled RR_* enum");
}

char *get_head_description(void)
{
        struct strbuf desc = STRBUF_INIT;
        struct wt_status_state state;
        memset(&state, 0, sizeof(state));
        wt_status_get_state(the_repository, &state, 1);
        if (state.rebase_in_progress ||
            state.rebase_interactive_in_progress) {
                if (state.branch)
                        strbuf_addf(&desc, _("(no branch, rebasing %s)"),
                                    state.branch);
                else
                        strbuf_addf(&desc, _("(no branch, rebasing detached HEAD %s)"),
                                    state.detached_from);
        } else if (state.bisect_in_progress)
                strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
                            state.branch);
        else if (state.detached_from) {
                if (state.detached_at)
                        strbuf_addf(&desc, _("(HEAD detached at %s)"),
                                state.detached_from);
                else
                        strbuf_addf(&desc, _("(HEAD detached from %s)"),
                                state.detached_from);
        } else
                strbuf_addstr(&desc, _("(no branch)"));

        wt_status_state_free_buffers(&state);

        return strbuf_detach(&desc, NULL);
}

static const char *get_symref(struct used_atom *atom, struct ref_array_item *ref)
{
        if (!ref->symref)
                return xstrdup("");
        else
                return show_ref(&atom->u.refname, ref->symref);
}

static const char *get_refname(struct used_atom *atom, struct ref_array_item *ref)
{
        if (ref->kind & FILTER_REFS_DETACHED_HEAD)
                return get_head_description();
        return show_ref(&atom->u.refname, ref->refname);
}

static int get_object(struct ref_array_item *ref, int deref, struct object **obj,
                      struct expand_data *oi, struct strbuf *err)
{
        /* parse_object_buffer() will set eaten to 0 if free() will be needed */
        int eaten = 1;
        if (oi->info.contentp) {
                /* We need to know that to use parse_object_buffer properly */
                oi->info.sizep = &oi->size;
                oi->info.typep = &oi->type;
        }
        if (oid_object_info_extended(the_repository, &oi->oid, &oi->info,
                                     OBJECT_INFO_LOOKUP_REPLACE))
                return strbuf_addf_ret(err, -1, _("missing object %s for %s"),
                                       oid_to_hex(&oi->oid), ref->refname);
        if (oi->info.disk_sizep && oi->disk_size < 0)
                BUG("Object size is less than zero.");

        if (oi->info.contentp) {
                *obj = parse_object_buffer(the_repository, &oi->oid, oi->type, oi->size, oi->content, &eaten);
                if (!*obj) {
                        if (!eaten)
                                free(oi->content);
                        return strbuf_addf_ret(err, -1, _("parse_object_buffer failed on %s for %s"),
                                               oid_to_hex(&oi->oid), ref->refname);
                }
                grab_values(ref->value, deref, *obj, oi);
        }

        grab_common_values(ref->value, deref, oi);
        if (!eaten)
                free(oi->content);
        return 0;
}

static void populate_worktree_map(struct hashmap *map, struct worktree **worktrees)
{
        int i;

        for (i = 0; worktrees[i]; i++) {
                if (worktrees[i]->head_ref) {
                        struct ref_to_worktree_entry *entry;
                        entry = xmalloc(sizeof(*entry));
                        entry->wt = worktrees[i];
                        hashmap_entry_init(&entry->ent,
                                        strhash(worktrees[i]->head_ref));

                        hashmap_add(map, &entry->ent);
                }
        }
}

static void lazy_init_worktree_map(void)
{
        if (ref_to_worktree_map.worktrees)
                return;

        ref_to_worktree_map.worktrees = get_worktrees();
        hashmap_init(&(ref_to_worktree_map.map), ref_to_worktree_map_cmpfnc, NULL, 0);
        populate_worktree_map(&(ref_to_worktree_map.map), ref_to_worktree_map.worktrees);
}

static char *get_worktree_path(const struct ref_array_item *ref)
{
        struct hashmap_entry entry, *e;
        struct ref_to_worktree_entry *lookup_result;

        lazy_init_worktree_map();

        hashmap_entry_init(&entry, strhash(ref->refname));
        e = hashmap_get(&(ref_to_worktree_map.map), &entry, ref->refname);

        if (!e)
                return xstrdup("");

        lookup_result = container_of(e, struct ref_to_worktree_entry, ent);

        return xstrdup(lookup_result->wt->path);
}

/*
 * Parse the object referred by ref, and grab needed value.
 */
static int populate_value(struct ref_array_item *ref, struct strbuf *err)
{
        struct object *obj;
        int i;
        struct object_info empty = OBJECT_INFO_INIT;
        int ahead_behind_atoms = 0;

        CALLOC_ARRAY(ref->value, used_atom_cnt);

        if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
                ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
                                             NULL, NULL);
                if (!ref->symref)
                        ref->symref = xstrdup("");
        }

        /* Fill in specials first */
        for (i = 0; i < used_atom_cnt; i++) {
                struct used_atom *atom = &used_atom[i];
                enum atom_type atom_type = atom->atom_type;
                const char *name = used_atom[i].name;
                struct atom_value *v = &ref->value[i];
                int deref = 0;
                const char *refname;
                struct branch *branch = NULL;

                v->s_size = ATOM_SIZE_UNSPECIFIED;
                v->handler = append_atom;
                v->atom = atom;

                if (*name == '*') {
                        deref = 1;
                        name++;
                }

                if (atom_type == ATOM_REFNAME)
                        refname = get_refname(atom, ref);
                else if (atom_type == ATOM_WORKTREEPATH) {
                        if (ref->kind == FILTER_REFS_BRANCHES)
                                v->s = get_worktree_path(ref);
                        else
                                v->s = xstrdup("");
                        continue;
                }
                else if (atom_type == ATOM_SYMREF)
                        refname = get_symref(atom, ref);
                else if (atom_type == ATOM_UPSTREAM) {
                        const char *branch_name;
                        /* only local branches may have an upstream */
                        if (!skip_prefix(ref->refname, "refs/heads/",
                                         &branch_name)) {
                                v->s = xstrdup("");
                                continue;
                        }
                        branch = branch_get(branch_name);

                        refname = branch_get_upstream(branch, NULL);
                        if (refname)
                                fill_remote_ref_details(atom, refname, branch, &v->s);
                        else
                                v->s = xstrdup("");
                        continue;
                } else if (atom_type == ATOM_PUSH && atom->u.remote_ref.push) {
                        const char *branch_name;
                        v->s = xstrdup("");
                        if (!skip_prefix(ref->refname, "refs/heads/",
                                         &branch_name))
                                continue;
                        branch = branch_get(branch_name);

                        if (atom->u.remote_ref.push_remote)
                                refname = NULL;
                        else {
                                refname = branch_get_push(branch, NULL);
                                if (!refname)
                                        continue;
                        }
                        /* We will definitely re-init v->s on the next line. */
                        free((char *)v->s);
                        fill_remote_ref_details(atom, refname, branch, &v->s);
                        continue;
                } else if (atom_type == ATOM_COLOR) {
                        v->s = xstrdup(atom->u.color);
                        continue;
                } else if (atom_type == ATOM_FLAG) {
                        char buf[256], *cp = buf;
                        if (ref->flag & REF_ISSYMREF)
                                cp = copy_advance(cp, ",symref");
                        if (ref->flag & REF_ISPACKED)
                                cp = copy_advance(cp, ",packed");
                        if (cp == buf)
                                v->s = xstrdup("");
                        else {
                                *cp = '\0';
                                v->s = xstrdup(buf + 1);
                        }
                        continue;
                } else if (!deref && atom_type == ATOM_OBJECTNAME &&
                           grab_oid(name, "objectname", &ref->objectname, v, atom)) {
                                continue;
                } else if (atom_type == ATOM_HEAD) {
                        if (atom->u.head && !strcmp(ref->refname, atom->u.head))
                                v->s = xstrdup("*");
                        else
                                v->s = xstrdup(" ");
                        continue;
                } else if (atom_type == ATOM_ALIGN) {
                        v->handler = align_atom_handler;
                        v->s = xstrdup("");
                        continue;
                } else if (atom_type == ATOM_END) {
                        v->handler = end_atom_handler;
                        v->s = xstrdup("");
                        continue;
                } else if (atom_type == ATOM_IF) {
                        const char *s;
                        if (skip_prefix(name, "if:", &s))
                                v->s = xstrdup(s);
                        else
                                v->s = xstrdup("");
                        v->handler = if_atom_handler;
                        continue;
                } else if (atom_type == ATOM_THEN) {
                        v->handler = then_atom_handler;
                        v->s = xstrdup("");
                        continue;
                } else if (atom_type == ATOM_ELSE) {
                        v->handler = else_atom_handler;
                        v->s = xstrdup("");
                        continue;
                } else if (atom_type == ATOM_REST) {
                        if (ref->rest)
                                v->s = xstrdup(ref->rest);
                        else
                                v->s = xstrdup("");
                        continue;
                } else if (atom_type == ATOM_AHEADBEHIND) {
                        if (ref->counts) {
                                const struct ahead_behind_count *count;
                                count = ref->counts[ahead_behind_atoms++];
                                v->s = xstrfmt("%d %d", count->ahead, count->behind);
                        } else {
                                /* Not a commit. */
                                v->s = xstrdup("");
                        }
                        continue;
                } else
                        continue;

                if (!deref)
                        v->s = xstrdup(refname);
                else
                        v->s = xstrfmt("%s^{}", refname);
                free((char *)refname);
        }

        for (i = 0; i < used_atom_cnt; i++) {
                struct atom_value *v = &ref->value[i];
                if (v->s == NULL && used_atom[i].source == SOURCE_NONE)
                        return strbuf_addf_ret(err, -1, _("missing object %s for %s"),
                                               oid_to_hex(&ref->objectname), ref->refname);
        }

        if (need_tagged)
                oi.info.contentp = &oi.content;
        if (!memcmp(&oi.info, &empty, sizeof(empty)) &&
            !memcmp(&oi_deref.info, &empty, sizeof(empty)))
                return 0;


        oi.oid = ref->objectname;
        if (get_object(ref, 0, &obj, &oi, err))
                return -1;

        /*
         * If there is no atom that wants to know about tagged
         * object, we are done.
         */
        if (!need_tagged || (obj->type != OBJ_TAG))
                return 0;

        /*
         * If it is a tag object, see if we use a value that derefs
         * the object, and if we do grab the object it refers to.
         */
        oi_deref.oid = *get_tagged_oid((struct tag *)obj);

        /*
         * NEEDSWORK: This derefs tag only once, which
         * is good to deal with chains of trust, but
         * is not consistent with what deref_tag() does
         * which peels the onion to the core.
         */
        return get_object(ref, 1, &obj, &oi_deref, err);
}

/*
 * Given a ref, return the value for the atom.  This lazily gets value
 * out of the object by calling populate value.
 */
static int get_ref_atom_value(struct ref_array_item *ref, int atom,
                              struct atom_value **v, struct strbuf *err)
{
        if (!ref->value) {
                if (populate_value(ref, err))
                        return -1;
                fill_missing_values(ref->value);
        }
        *v = &ref->value[atom];
        return 0;
}

/*
 * Return 1 if the refname matches one of the patterns, otherwise 0.
 * A pattern can be a literal prefix (e.g. a refname "refs/heads/master"
 * matches a pattern "refs/heads/mas") or a wildcard (e.g. the same ref
 * matches "refs/heads/mas*", too).
 */
static int match_pattern(const struct ref_filter *filter, const char *refname)
{
        const char **patterns = filter->name_patterns;
        unsigned flags = 0;

        if (filter->ignore_case)
                flags |= WM_CASEFOLD;

        /*
         * When no '--format' option is given we need to skip the prefix
         * for matching refs of tags and branches.
         */
        (void)(skip_prefix(refname, "refs/tags/", &refname) ||
               skip_prefix(refname, "refs/heads/", &refname) ||
               skip_prefix(refname, "refs/remotes/", &refname) ||
               skip_prefix(refname, "refs/", &refname));

        for (; *patterns; patterns++) {
                if (!wildmatch(*patterns, refname, flags))
                        return 1;
        }
        return 0;
}

/*
 * Return 1 if the refname matches one of the patterns, otherwise 0.
 * A pattern can be path prefix (e.g. a refname "refs/heads/master"
 * matches a pattern "refs/heads/" but not "refs/heads/m") or a
 * wildcard (e.g. the same ref matches "refs/heads/m*", too).
 */
static int match_name_as_path(const struct ref_filter *filter, const char *refname)
{
        const char **pattern = filter->name_patterns;
        int namelen = strlen(refname);
        unsigned flags = WM_PATHNAME;

        if (filter->ignore_case)
                flags |= WM_CASEFOLD;

        for (; *pattern; pattern++) {
                const char *p = *pattern;
                int plen = strlen(p);

                if ((plen <= namelen) &&
                    !strncmp(refname, p, plen) &&
                    (refname[plen] == '\0' ||
                     refname[plen] == '/' ||
                     p[plen-1] == '/'))
                        return 1;
                if (!wildmatch(p, refname, flags))
                        return 1;
        }
        return 0;
}

/* Return 1 if the refname matches one of the patterns, otherwise 0. */
static int filter_pattern_match(struct ref_filter *filter, const char *refname)
{
        if (!*filter->name_patterns)
                return 1; /* No pattern always matches */
        if (filter->match_as_path)
                return match_name_as_path(filter, refname);
        return match_pattern(filter, refname);
}

/*
 * This is the same as for_each_fullref_in(), but it tries to iterate
 * only over the patterns we'll care about. Note that it _doesn't_ do a full
 * pattern match, so the callback still has to match each ref individually.
 */
static int for_each_fullref_in_pattern(struct ref_filter *filter,
                                       each_ref_fn cb,
                                       void *cb_data)
{
        if (!filter->match_as_path) {
                /*
                 * in this case, the patterns are applied after
                 * prefixes like "refs/heads/" etc. are stripped off,
                 * so we have to look at everything:
                 */
                return for_each_fullref_in("", cb, cb_data);
        }

        if (filter->ignore_case) {
                /*
                 * we can't handle case-insensitive comparisons,
                 * so just return everything and let the caller
                 * sort it out.
                 */
                return for_each_fullref_in("", cb, cb_data);
        }

        if (!filter->name_patterns[0]) {
                /* no patterns; we have to look at everything */
                return for_each_fullref_in("", cb, cb_data);
        }

        return refs_for_each_fullref_in_prefixes(get_main_ref_store(the_repository),
                                                 NULL, filter->name_patterns,
                                                 cb, cb_data);
}

/*
 * Given a ref (oid, refname), check if the ref belongs to the array
 * of oids. If the given ref is a tag, check if the given tag points
 * at one of the oids in the given oid array.
 * NEEDSWORK:
 * 1. Only a single level of indirection is obtained, we might want to
 * change this to account for multiple levels (e.g. annotated tags
 * pointing to annotated tags pointing to a commit.)
 * 2. As the refs are cached we might know what refname peels to without
 * the need to parse the object via parse_object(). peel_ref() might be a
 * more efficient alternative to obtain the pointee.
 */
static const struct object_id *match_points_at(struct oid_array *points_at,
                                               const struct object_id *oid,
                                               const char *refname)
{
        const struct object_id *tagged_oid = NULL;
        struct object *obj;

        if (oid_array_lookup(points_at, oid) >= 0)
                return oid;
        obj = parse_object(the_repository, oid);
        if (!obj)
                die(_("malformed object at '%s'"), refname);
        if (obj->type == OBJ_TAG)
                tagged_oid = get_tagged_oid((struct tag *)obj);
        if (tagged_oid && oid_array_lookup(points_at, tagged_oid) >= 0)
                return tagged_oid;
        return NULL;
}

/*
 * Allocate space for a new ref_array_item and copy the name and oid to it.
 *
 * Callers can then fill in other struct members at their leisure.
 */
static struct ref_array_item *new_ref_array_item(const char *refname,
                                                 const struct object_id *oid)
{
        struct ref_array_item *ref;

        FLEX_ALLOC_STR(ref, refname, refname);
        oidcpy(&ref->objectname, oid);
        ref->rest = NULL;

        return ref;
}

struct ref_array_item *ref_array_push(struct ref_array *array,
                                      const char *refname,
                                      const struct object_id *oid)
{
        struct ref_array_item *ref = new_ref_array_item(refname, oid);

        ALLOC_GROW(array->items, array->nr + 1, array->alloc);
        array->items[array->nr++] = ref;

        return ref;
}

static int ref_kind_from_refname(const char *refname)
{
        unsigned int i;

        static struct {
                const char *prefix;
                unsigned int kind;
        } ref_kind[] = {
                { "refs/heads/" , FILTER_REFS_BRANCHES },
                { "refs/remotes/" , FILTER_REFS_REMOTES },
                { "refs/tags/", FILTER_REFS_TAGS}
        };

        if (!strcmp(refname, "HEAD"))
                return FILTER_REFS_DETACHED_HEAD;

        for (i = 0; i < ARRAY_SIZE(ref_kind); i++) {
                if (starts_with(refname, ref_kind[i].prefix))
                        return ref_kind[i].kind;
        }

        return FILTER_REFS_OTHERS;
}

static int filter_ref_kind(struct ref_filter *filter, const char *refname)
{
        if (filter->kind == FILTER_REFS_BRANCHES ||
            filter->kind == FILTER_REFS_REMOTES ||
            filter->kind == FILTER_REFS_TAGS)
                return filter->kind;
        return ref_kind_from_refname(refname);
}

struct ref_filter_cbdata {
        struct ref_array *array;
        struct ref_filter *filter;
        struct contains_cache contains_cache;
        struct contains_cache no_contains_cache;
};

/*
 * A call-back given to for_each_ref().  Filter refs and keep them for
 * later object processing.
 */
static int ref_filter_handler(const char *refname, const struct object_id *oid, int flag, void *cb_data)
{
        struct ref_filter_cbdata *ref_cbdata = cb_data;
        struct ref_filter *filter = ref_cbdata->filter;
        struct ref_array_item *ref;
        struct commit *commit = NULL;
        unsigned int kind;

        if (flag & REF_BAD_NAME) {
                warning(_("ignoring ref with broken name %s"), refname);
                return 0;
        }

        if (flag & REF_ISBROKEN) {
                warning(_("ignoring broken ref %s"), refname);
                return 0;
        }

        /* Obtain the current ref kind from filter_ref_kind() and ignore unwanted refs. */
        kind = filter_ref_kind(filter, refname);
        if (!(kind & filter->kind))
                return 0;

        if (!filter_pattern_match(filter, refname))
                return 0;

        if (filter->points_at.nr && !match_points_at(&filter->points_at, oid, refname))
                return 0;

        /*
         * A merge filter is applied on refs pointing to commits. Hence
         * obtain the commit using the 'oid' available and discard all
         * non-commits early. The actual filtering is done later.
         */
        if (filter->reachable_from || filter->unreachable_from ||
            filter->with_commit || filter->no_commit || filter->verbose) {
                commit = lookup_commit_reference_gently(the_repository, oid, 1);
                if (!commit)
                        return 0;
                /* We perform the filtering for the '--contains' option... */
                if (filter->with_commit &&
                    !commit_contains(filter, commit, filter->with_commit, &ref_cbdata->contains_cache))
                        return 0;
                /* ...or for the `--no-contains' option */
                if (filter->no_commit &&
                    commit_contains(filter, commit, filter->no_commit, &ref_cbdata->no_contains_cache))
                        return 0;
        }

        /*
         * We do not open the object yet; sort may only need refname
         * to do its job and the resulting list may yet to be pruned
         * by maxcount logic.
         */
        ref = ref_array_push(ref_cbdata->array, refname, oid);
        ref->commit = commit;
        ref->flag = flag;
        ref->kind = kind;

        return 0;
}

/*  Free memory allocated for a ref_array_item */
static void free_array_item(struct ref_array_item *item)
{
        free((char *)item->symref);
        if (item->value) {
                int i;
                for (i = 0; i < used_atom_cnt; i++)
                        free((char *)item->value[i].s);
                free(item->value);
        }
        free(item->counts);
        free(item);
}

/* Free all memory allocated for ref_array */
void ref_array_clear(struct ref_array *array)
{
        int i;

        for (i = 0; i < array->nr; i++)
                free_array_item(array->items[i]);
        FREE_AND_NULL(array->items);
        array->nr = array->alloc = 0;

        for (i = 0; i < used_atom_cnt; i++) {
                struct used_atom *atom = &used_atom[i];
                if (atom->atom_type == ATOM_HEAD)
                        free(atom->u.head);
                free((char *)atom->name);
        }
        FREE_AND_NULL(used_atom);
        used_atom_cnt = 0;

        if (ref_to_worktree_map.worktrees) {
                hashmap_clear_and_free(&(ref_to_worktree_map.map),
                                        struct ref_to_worktree_entry, ent);
                free_worktrees(ref_to_worktree_map.worktrees);
                ref_to_worktree_map.worktrees = NULL;
        }

        FREE_AND_NULL(array->counts);
}

#define EXCLUDE_REACHED 0
#define INCLUDE_REACHED 1
static void reach_filter(struct ref_array *array,
                         struct commit_list *check_reachable,
                         int include_reached)
{
        int i, old_nr;
        struct commit **to_clear;

        if (!check_reachable)
                return;

        CALLOC_ARRAY(to_clear, array->nr);
        for (i = 0; i < array->nr; i++) {
                struct ref_array_item *item = array->items[i];
                to_clear[i] = item->commit;
        }

        tips_reachable_from_bases(the_repository,
                                  check_reachable,
                                  to_clear, array->nr,
                                  UNINTERESTING);

        old_nr = array->nr;
        array->nr = 0;

        for (i = 0; i < old_nr; i++) {
                struct ref_array_item *item = array->items[i];
                struct commit *commit = item->commit;

                int is_merged = !!(commit->object.flags & UNINTERESTING);

                if (is_merged == include_reached)
                        array->items[array->nr++] = array->items[i];
                else
                        free_array_item(item);
        }

        clear_commit_marks_many(old_nr, to_clear, ALL_REV_FLAGS);

        while (check_reachable) {
                struct commit *merge_commit = pop_commit(&check_reachable);
                clear_commit_marks(merge_commit, ALL_REV_FLAGS);
        }

        free(to_clear);
}

void filter_ahead_behind(struct repository *r,
                         struct ref_format *format,
                         struct ref_array *array)
{
        struct commit **commits;
        size_t commits_nr = format->bases.nr + array->nr;

        if (!format->bases.nr || !array->nr)
                return;

        ALLOC_ARRAY(commits, commits_nr);
        for (size_t i = 0; i < format->bases.nr; i++)
                commits[i] = format->bases.items[i].util;

        ALLOC_ARRAY(array->counts, st_mult(format->bases.nr, array->nr));

        commits_nr = format->bases.nr;
        array->counts_nr = 0;
        for (size_t i = 0; i < array->nr; i++) {
                const char *name = array->items[i]->refname;
                commits[commits_nr] = lookup_commit_reference_by_name(name);

                if (!commits[commits_nr])
                        continue;

                CALLOC_ARRAY(array->items[i]->counts, format->bases.nr);
                for (size_t j = 0; j < format->bases.nr; j++) {
                        struct ahead_behind_count *count;
                        count = &array->counts[array->counts_nr++];
                        count->tip_index = commits_nr;
                        count->base_index = j;

                        array->items[i]->counts[j] = count;
                }
                commits_nr++;
        }

        ahead_behind(r, commits, commits_nr, array->counts, array->counts_nr);
        free(commits);
}

/*
 * API for filtering a set of refs. Based on the type of refs the user
 * has requested, we iterate through those refs and apply filters
 * as per the given ref_filter structure and finally store the
 * filtered refs in the ref_array structure.
 */
int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int type)
{
        struct ref_filter_cbdata ref_cbdata;
        int save_commit_buffer_orig;
        int ret = 0;

        ref_cbdata.array = array;
        ref_cbdata.filter = filter;

        filter->kind = type & FILTER_REFS_KIND_MASK;

        save_commit_buffer_orig = save_commit_buffer;
        save_commit_buffer = 0;

        init_contains_cache(&ref_cbdata.contains_cache);
        init_contains_cache(&ref_cbdata.no_contains_cache);

        /*  Simple per-ref filtering */
        if (!filter->kind)
                die("filter_refs: invalid type");
        else {
                /*
                 * For common cases where we need only branches or remotes or tags,
                 * we only iterate through those refs. If a mix of refs is needed,
                 * we iterate over all refs and filter out required refs with the help
                 * of filter_ref_kind().
                 */
                if (filter->kind == FILTER_REFS_BRANCHES)
                        ret = for_each_fullref_in("refs/heads/", ref_filter_handler, &ref_cbdata);
                else if (filter->kind == FILTER_REFS_REMOTES)
                        ret = for_each_fullref_in("refs/remotes/", ref_filter_handler, &ref_cbdata);
                else if (filter->kind == FILTER_REFS_TAGS)
                        ret = for_each_fullref_in("refs/tags/", ref_filter_handler, &ref_cbdata);
                else if (filter->kind & FILTER_REFS_ALL)
                        ret = for_each_fullref_in_pattern(filter, ref_filter_handler, &ref_cbdata);
                if (!ret && (filter->kind & FILTER_REFS_DETACHED_HEAD))
                        head_ref(ref_filter_handler, &ref_cbdata);
        }

        clear_contains_cache(&ref_cbdata.contains_cache);
        clear_contains_cache(&ref_cbdata.no_contains_cache);

        /*  Filters that need revision walking */
        reach_filter(array, filter->reachable_from, INCLUDE_REACHED);
        reach_filter(array, filter->unreachable_from, EXCLUDE_REACHED);

        save_commit_buffer = save_commit_buffer_orig;
        return ret;
}

static int compare_detached_head(struct ref_array_item *a, struct ref_array_item *b)
{
        if (!(a->kind ^ b->kind))
                BUG("ref_kind_from_refname() should only mark one ref as HEAD");
        if (a->kind & FILTER_REFS_DETACHED_HEAD)
                return -1;
        else if (b->kind & FILTER_REFS_DETACHED_HEAD)
                return 1;
        BUG("should have died in the xor check above");
        return 0;
}

static int memcasecmp(const void *vs1, const void *vs2, size_t n)
{
        const char *s1 = vs1, *s2 = vs2;
        const char *end = s1 + n;

        for (; s1 < end; s1++, s2++) {
                int diff = tolower(*s1) - tolower(*s2);
                if (diff)
                        return diff;
        }
        return 0;
}

struct ref_sorting {
        struct ref_sorting *next;
        int atom; /* index into used_atom array (internal) */
        enum ref_sorting_order sort_flags;
};

static int cmp_ref_sorting(struct ref_sorting *s, struct ref_array_item *a, struct ref_array_item *b)
{
        struct atom_value *va, *vb;
        int cmp;
        int cmp_detached_head = 0;
        cmp_type cmp_type = used_atom[s->atom].type;
        struct strbuf err = STRBUF_INIT;

        if (get_ref_atom_value(a, s->atom, &va, &err))
                die("%s", err.buf);
        if (get_ref_atom_value(b, s->atom, &vb, &err))
                die("%s", err.buf);
        strbuf_release(&err);
        if (s->sort_flags & REF_SORTING_DETACHED_HEAD_FIRST &&
            ((a->kind | b->kind) & FILTER_REFS_DETACHED_HEAD)) {
                cmp = compare_detached_head(a, b);
                cmp_detached_head = 1;
        } else if (s->sort_flags & REF_SORTING_VERSION) {
                cmp = versioncmp(va->s, vb->s);
        } else if (cmp_type == FIELD_STR) {
                if (va->s_size < 0 && vb->s_size < 0) {
                        int (*cmp_fn)(const char *, const char *);
                        cmp_fn = s->sort_flags & REF_SORTING_ICASE
                                ? strcasecmp : strcmp;
                        cmp = cmp_fn(va->s, vb->s);
                } else {
                        size_t a_size = va->s_size < 0 ?
                                        strlen(va->s) : va->s_size;
                        size_t b_size = vb->s_size < 0 ?
                                        strlen(vb->s) : vb->s_size;
                        int (*cmp_fn)(const void *, const void *, size_t);
                        cmp_fn = s->sort_flags & REF_SORTING_ICASE
                                ? memcasecmp : memcmp;

                        cmp = cmp_fn(va->s, vb->s, b_size > a_size ?
                                     a_size : b_size);
                        if (!cmp) {
                                if (a_size > b_size)
                                        cmp = 1;
                                else if (a_size < b_size)
                                        cmp = -1;
                        }
                }
        } else {
                if (va->value < vb->value)
                        cmp = -1;
                else if (va->value == vb->value)
                        cmp = 0;
                else
                        cmp = 1;
        }

        return (s->sort_flags & REF_SORTING_REVERSE && !cmp_detached_head)
                ? -cmp : cmp;
}

static int compare_refs(const void *a_, const void *b_, void *ref_sorting)
{
        struct ref_array_item *a = *((struct ref_array_item **)a_);
        struct ref_array_item *b = *((struct ref_array_item **)b_);
        struct ref_sorting *s;

        for (s = ref_sorting; s; s = s->next) {
                int cmp = cmp_ref_sorting(s, a, b);
                if (cmp)
                        return cmp;
        }
        s = ref_sorting;
        return s && s->sort_flags & REF_SORTING_ICASE ?
                strcasecmp(a->refname, b->refname) :
                strcmp(a->refname, b->refname);
}

void ref_sorting_set_sort_flags_all(struct ref_sorting *sorting,
                                    unsigned int mask, int on)
{
        for (; sorting; sorting = sorting->next) {
                if (on)
                        sorting->sort_flags |= mask;
                else
                        sorting->sort_flags &= ~mask;
        }
}

void ref_array_sort(struct ref_sorting *sorting, struct ref_array *array)
{
        QSORT_S(array->items, array->nr, compare_refs, sorting);
}

static void append_literal(const char *cp, const char *ep, struct ref_formatting_state *state)
{
        struct strbuf *s = &state->stack->output;

        while (*cp && (!ep || cp < ep)) {
                if (*cp == '%') {
                        if (cp[1] == '%')
                                cp++;
                        else {
                                int ch = hex2chr(cp + 1);
                                if (0 <= ch) {
                                        strbuf_addch(s, ch);
                                        cp += 3;
                                        continue;
                                }
                        }
                }
                strbuf_addch(s, *cp);
                cp++;
        }
}

int format_ref_array_item(struct ref_array_item *info,
                          struct ref_format *format,
                          struct strbuf *final_buf,
                          struct strbuf *error_buf)
{
        const char *cp, *sp, *ep;
        struct ref_formatting_state state = REF_FORMATTING_STATE_INIT;

        state.quote_style = format->quote_style;
        push_stack_element(&state.stack);

        for (cp = format->format; *cp && (sp = find_next(cp)); cp = ep + 1) {
                struct atom_value *atomv;
                int pos;

                ep = strchr(sp, ')');
                if (cp < sp)
                        append_literal(cp, sp, &state);
                pos = parse_ref_filter_atom(format, sp + 2, ep, error_buf);
                if (pos < 0 || get_ref_atom_value(info, pos, &atomv, error_buf) ||
                    atomv->handler(atomv, &state, error_buf)) {
                        pop_stack_element(&state.stack);
                        return -1;
                }
        }
        if (*cp) {
                sp = cp + strlen(cp);
                append_literal(cp, sp, &state);
        }
        if (format->need_color_reset_at_eol) {
                struct atom_value resetv = ATOM_VALUE_INIT;
                resetv.s = GIT_COLOR_RESET;
                if (append_atom(&resetv, &state, error_buf)) {
                        pop_stack_element(&state.stack);
                        return -1;
                }
        }
        if (state.stack->prev) {
                pop_stack_element(&state.stack);
                return strbuf_addf_ret(error_buf, -1, _("format: %%(end) atom missing"));
        }
        strbuf_addbuf(final_buf, &state.stack->output);
        pop_stack_element(&state.stack);
        return 0;
}

void pretty_print_ref(const char *name, const struct object_id *oid,
                      struct ref_format *format)
{
        struct ref_array_item *ref_item;
        struct strbuf output = STRBUF_INIT;
        struct strbuf err = STRBUF_INIT;

        ref_item = new_ref_array_item(name, oid);
        ref_item->kind = ref_kind_from_refname(name);
        if (format_ref_array_item(ref_item, format, &output, &err))
                die("%s", err.buf);
        fwrite(output.buf, 1, output.len, stdout);
        putchar('\n');

        strbuf_release(&err);
        strbuf_release(&output);
        free_array_item(ref_item);
}

static int parse_sorting_atom(const char *atom)
{
        /*
         * This parses an atom using a dummy ref_format, since we don't
         * actually care about the formatting details.
         */
        struct ref_format dummy = REF_FORMAT_INIT;
        const char *end = atom + strlen(atom);
        struct strbuf err = STRBUF_INIT;
        int res = parse_ref_filter_atom(&dummy, atom, end, &err);
        if (res < 0)
                die("%s", err.buf);
        strbuf_release(&err);
        return res;
}

/*  If no sorting option is given, use refname to sort as default */
static struct ref_sorting *ref_default_sorting(void)
{
        static const char cstr_name[] = "refname";

        struct ref_sorting *sorting = xcalloc(1, sizeof(*sorting));

        sorting->next = NULL;
        sorting->atom = parse_sorting_atom(cstr_name);
        return sorting;
}

static void parse_ref_sorting(struct ref_sorting **sorting_tail, const char *arg)
{
        struct ref_sorting *s;

        CALLOC_ARRAY(s, 1);
        s->next = *sorting_tail;
        *sorting_tail = s;

        if (*arg == '-') {
                s->sort_flags |= REF_SORTING_REVERSE;
                arg++;
        }
        if (skip_prefix(arg, "version:", &arg) ||
            skip_prefix(arg, "v:", &arg))
                s->sort_flags |= REF_SORTING_VERSION;
        s->atom = parse_sorting_atom(arg);
}

struct ref_sorting *ref_sorting_options(struct string_list *options)
{
        struct string_list_item *item;
        struct ref_sorting *sorting = NULL, **tail = &sorting;

        if (!options->nr) {
                sorting = ref_default_sorting();
        } else {
                for_each_string_list_item(item, options)
                        parse_ref_sorting(tail, item->string);
        }

        /*
         * From here on, the ref_sorting list should be used to talk
         * about the sort order used for the output.  The caller
         * should not touch the string form anymore.
         */
        string_list_clear(options, 0);
        return sorting;
}

void ref_sorting_release(struct ref_sorting *sorting)
{
        while (sorting) {
                struct ref_sorting *next = sorting->next;
                free(sorting);
                sorting = next;
        }
}

int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset)
{
        struct ref_filter *rf = opt->value;
        struct object_id oid;
        struct commit *merge_commit;

        BUG_ON_OPT_NEG(unset);

        if (repo_get_oid(the_repository, arg, &oid))
                die(_("malformed object name %s"), arg);

        merge_commit = lookup_commit_reference_gently(the_repository, &oid, 0);

        if (!merge_commit)
                return error(_("option `%s' must point to a commit"), opt->long_name);

        if (starts_with(opt->long_name, "no"))
                commit_list_insert(merge_commit, &rf->unreachable_from);
        else
                commit_list_insert(merge_commit, &rf->reachable_from);

        return 0;
}