Merge branch 'jc/doc-submitting-patches-choice-of-base'

[git/debian.git] / add-interactive.c

#include "cache.h"
#include "add-interactive.h"
#include "color.h"
#include "config.h"
#include "diffcore.h"
#include "revision.h"
#include "refs.h"
#include "string-list.h"
#include "lockfile.h"
#include "dir.h"
#include "run-command.h"
#include "prompt.h"

static void init_color(struct repository *r, struct add_i_state *s,
                       const char *section_and_slot, char *dst,
                       const char *default_color)
{
        char *key = xstrfmt("color.%s", section_and_slot);
        const char *value;

        if (!s->use_color)
                dst[0] = '\0';
        else if (repo_config_get_value(r, key, &value) ||
                 color_parse(value, dst))
                strlcpy(dst, default_color, COLOR_MAXLEN);

        free(key);
}

void init_add_i_state(struct add_i_state *s, struct repository *r)
{
        const char *value;

        s->r = r;

        if (repo_config_get_value(r, "color.interactive", &value))
                s->use_color = -1;
        else
                s->use_color =
                        git_config_colorbool("color.interactive", value);
        s->use_color = want_color(s->use_color);

        init_color(r, s, "interactive.header", s->header_color, GIT_COLOR_BOLD);
        init_color(r, s, "interactive.help", s->help_color, GIT_COLOR_BOLD_RED);
        init_color(r, s, "interactive.prompt", s->prompt_color,
                   GIT_COLOR_BOLD_BLUE);
        init_color(r, s, "interactive.error", s->error_color,
                   GIT_COLOR_BOLD_RED);

        init_color(r, s, "diff.frag", s->fraginfo_color,
                   diff_get_color(s->use_color, DIFF_FRAGINFO));
        init_color(r, s, "diff.context", s->context_color, "fall back");
        if (!strcmp(s->context_color, "fall back"))
                init_color(r, s, "diff.plain", s->context_color,
                           diff_get_color(s->use_color, DIFF_CONTEXT));
        init_color(r, s, "diff.old", s->file_old_color,
                diff_get_color(s->use_color, DIFF_FILE_OLD));
        init_color(r, s, "diff.new", s->file_new_color,
                diff_get_color(s->use_color, DIFF_FILE_NEW));

        strlcpy(s->reset_color,
                s->use_color ? GIT_COLOR_RESET : "", COLOR_MAXLEN);

        FREE_AND_NULL(s->interactive_diff_filter);
        git_config_get_string("interactive.difffilter",
                              &s->interactive_diff_filter);

        FREE_AND_NULL(s->interactive_diff_algorithm);
        git_config_get_string("diff.algorithm",
                              &s->interactive_diff_algorithm);

        git_config_get_bool("interactive.singlekey", &s->use_single_key);
}

void clear_add_i_state(struct add_i_state *s)
{
        FREE_AND_NULL(s->interactive_diff_filter);
        FREE_AND_NULL(s->interactive_diff_algorithm);
        memset(s, 0, sizeof(*s));
        s->use_color = -1;
}

/*
 * A "prefix item list" is a list of items that are identified by a string, and
 * a unique prefix (if any) is determined for each item.
 *
 * It is implemented in the form of a pair of `string_list`s, the first one
 * duplicating the strings, with the `util` field pointing at a structure whose
 * first field must be `size_t prefix_length`.
 *
 * That `prefix_length` field will be computed by `find_unique_prefixes()`; It
 * will be set to zero if no valid, unique prefix could be found.
 *
 * The second `string_list` is called `sorted` and does _not_ duplicate the
 * strings but simply reuses the first one's, with the `util` field pointing at
 * the `string_item_list` of the first `string_list`. It  will be populated and
 * sorted by `find_unique_prefixes()`.
 */
struct prefix_item_list {
        struct string_list items;
        struct string_list sorted;
        int *selected; /* for multi-selections */
        size_t min_length, max_length;
};
#define PREFIX_ITEM_LIST_INIT { \
        .items = STRING_LIST_INIT_DUP, \
        .sorted = STRING_LIST_INIT_NODUP, \
        .min_length = 1, \
        .max_length = 4, \
}

static void prefix_item_list_clear(struct prefix_item_list *list)
{
        string_list_clear(&list->items, 1);
        string_list_clear(&list->sorted, 0);
        FREE_AND_NULL(list->selected);
}

static void extend_prefix_length(struct string_list_item *p,
                                 const char *other_string, size_t max_length)
{
        size_t *len = p->util;

        if (!*len || memcmp(p->string, other_string, *len))
                return;

        for (;;) {
                char c = p->string[*len];

                /*
                 * Is `p` a strict prefix of `other`? Or have we exhausted the
                 * maximal length of the prefix? Or is the current character a
                 * multi-byte UTF-8 one? If so, there is no valid, unique
                 * prefix.
                 */
                if (!c || ++*len > max_length || !isascii(c)) {
                        *len = 0;
                        break;
                }

                if (c != other_string[*len - 1])
                        break;
        }
}

static void find_unique_prefixes(struct prefix_item_list *list)
{
        size_t i;

        if (list->sorted.nr == list->items.nr)
                return;

        string_list_clear(&list->sorted, 0);
        /* Avoid reallocating incrementally */
        list->sorted.items = xmalloc(st_mult(sizeof(*list->sorted.items),
                                             list->items.nr));
        list->sorted.nr = list->sorted.alloc = list->items.nr;

        for (i = 0; i < list->items.nr; i++) {
                list->sorted.items[i].string = list->items.items[i].string;
                list->sorted.items[i].util = list->items.items + i;
        }

        string_list_sort(&list->sorted);

        for (i = 0; i < list->sorted.nr; i++) {
                struct string_list_item *sorted_item = list->sorted.items + i;
                struct string_list_item *item = sorted_item->util;
                size_t *len = item->util;

                *len = 0;
                while (*len < list->min_length) {
                        char c = item->string[(*len)++];

                        if (!c || !isascii(c)) {
                                *len = 0;
                                break;
                        }
                }

                if (i > 0)
                        extend_prefix_length(item, sorted_item[-1].string,
                                             list->max_length);
                if (i + 1 < list->sorted.nr)
                        extend_prefix_length(item, sorted_item[1].string,
                                             list->max_length);
        }
}

static ssize_t find_unique(const char *string, struct prefix_item_list *list)
{
        int index = string_list_find_insert_index(&list->sorted, string, 1);
        struct string_list_item *item;

        if (list->items.nr != list->sorted.nr)
                BUG("prefix_item_list in inconsistent state (%"PRIuMAX
                    " vs %"PRIuMAX")",
                    (uintmax_t)list->items.nr, (uintmax_t)list->sorted.nr);

        if (index < 0)
                item = list->sorted.items[-1 - index].util;
        else if (index > 0 &&
                 starts_with(list->sorted.items[index - 1].string, string))
                return -1;
        else if (index + 1 < list->sorted.nr &&
                 starts_with(list->sorted.items[index + 1].string, string))
                return -1;
        else if (index < list->sorted.nr &&
                 starts_with(list->sorted.items[index].string, string))
                item = list->sorted.items[index].util;
        else
                return -1;
        return item - list->items.items;
}

struct list_options {
        int columns;
        const char *header;
        void (*print_item)(int i, int selected, struct string_list_item *item,
                           void *print_item_data);
        void *print_item_data;
};

static void list(struct add_i_state *s, struct string_list *list, int *selected,
                 struct list_options *opts)
{
        int i, last_lf = 0;

        if (!list->nr)
                return;

        if (opts->header)
                color_fprintf_ln(stdout, s->header_color,
                                 "%s", opts->header);

        for (i = 0; i < list->nr; i++) {
                opts->print_item(i, selected ? selected[i] : 0, list->items + i,
                                 opts->print_item_data);

                if ((opts->columns) && ((i + 1) % (opts->columns))) {
                        putchar('\t');
                        last_lf = 0;
                }
                else {
                        putchar('\n');
                        last_lf = 1;
                }
        }

        if (!last_lf)
                putchar('\n');
}
struct list_and_choose_options {
        struct list_options list_opts;

        const char *prompt;
        enum {
                SINGLETON = (1<<0),
                IMMEDIATE = (1<<1),
        } flags;
        void (*print_help)(struct add_i_state *s);
};

#define LIST_AND_CHOOSE_ERROR (-1)
#define LIST_AND_CHOOSE_QUIT  (-2)

/*
 * Returns the selected index in singleton mode, the number of selected items
 * otherwise.
 *
 * If an error occurred, returns `LIST_AND_CHOOSE_ERROR`. Upon EOF,
 * `LIST_AND_CHOOSE_QUIT` is returned.
 */
static ssize_t list_and_choose(struct add_i_state *s,
                               struct prefix_item_list *items,
                               struct list_and_choose_options *opts)
{
        int singleton = opts->flags & SINGLETON;
        int immediate = opts->flags & IMMEDIATE;

        struct strbuf input = STRBUF_INIT;
        ssize_t res = singleton ? LIST_AND_CHOOSE_ERROR : 0;

        if (!singleton) {
                free(items->selected);
                CALLOC_ARRAY(items->selected, items->items.nr);
        }

        if (singleton && !immediate)
                BUG("singleton requires immediate");

        find_unique_prefixes(items);

        for (;;) {
                char *p;

                strbuf_reset(&input);

                list(s, &items->items, items->selected, &opts->list_opts);

                color_fprintf(stdout, s->prompt_color, "%s", opts->prompt);
                fputs(singleton ? "> " : ">> ", stdout);
                fflush(stdout);

                if (git_read_line_interactively(&input) == EOF) {
                        putchar('\n');
                        if (immediate)
                                res = LIST_AND_CHOOSE_QUIT;
                        break;
                }

                if (!input.len)
                        break;

                if (!strcmp(input.buf, "?")) {
                        opts->print_help(s);
                        continue;
                }

                p = input.buf;
                for (;;) {
                        size_t sep = strcspn(p, " \t\r\n,");
                        int choose = 1;
                        /* `from` is inclusive, `to` is exclusive */
                        ssize_t from = -1, to = -1;

                        if (!sep) {
                                if (!*p)
                                        break;
                                p++;
                                continue;
                        }

                        /* Input that begins with '-'; de-select */
                        if (*p == '-') {
                                choose = 0;
                                p++;
                                sep--;
                        }

                        if (sep == 1 && *p == '*') {
                                from = 0;
                                to = items->items.nr;
                        } else if (isdigit(*p)) {
                                char *endp;
                                /*
                                 * A range can be specified like 5-7 or 5-.
                                 *
                                 * Note: `from` is 0-based while the user input
                                 * is 1-based, hence we have to decrement by
                                 * one. We do not have to decrement `to` even
                                 * if it is 0-based because it is an exclusive
                                 * boundary.
                                 */
                                from = strtoul(p, &endp, 10) - 1;
                                if (endp == p + sep)
                                        to = from + 1;
                                else if (*endp == '-') {
                                        if (isdigit(*(++endp)))
                                                to = strtoul(endp, &endp, 10);
                                        else
                                                to = items->items.nr;
                                        /* extra characters after the range? */
                                        if (endp != p + sep)
                                                from = -1;
                                }
                        }

                        if (p[sep])
                                p[sep++] = '\0';
                        if (from < 0) {
                                from = find_unique(p, items);
                                if (from >= 0)
                                        to = from + 1;
                        }

                        if (from < 0 || from >= items->items.nr ||
                            (singleton && from + 1 != to)) {
                                color_fprintf_ln(stderr, s->error_color,
                                                 _("Huh (%s)?"), p);
                                break;
                        } else if (singleton) {
                                res = from;
                                break;
                        }

                        if (to > items->items.nr)
                                to = items->items.nr;

                        for (; from < to; from++)
                                if (items->selected[from] != choose) {
                                        items->selected[from] = choose;
                                        res += choose ? +1 : -1;
                                }

                        p += sep;
                }

                if ((immediate && res != LIST_AND_CHOOSE_ERROR) ||
                    !strcmp(input.buf, "*"))
                        break;
        }

        strbuf_release(&input);
        return res;
}

struct adddel {
        uintmax_t add, del;
        unsigned seen:1, unmerged:1, binary:1;
};

struct file_item {
        size_t prefix_length;
        struct adddel index, worktree;
};

static void add_file_item(struct string_list *files, const char *name)
{
        struct file_item *item = xcalloc(1, sizeof(*item));

        string_list_append(files, name)->util = item;
}

struct pathname_entry {
        struct hashmap_entry ent;
        const char *name;
        struct file_item *item;
};

static int pathname_entry_cmp(const void *unused_cmp_data,
                              const struct hashmap_entry *he1,
                              const struct hashmap_entry *he2,
                              const void *name)
{
        const struct pathname_entry *e1 =
                container_of(he1, const struct pathname_entry, ent);
        const struct pathname_entry *e2 =
                container_of(he2, const struct pathname_entry, ent);

        return strcmp(e1->name, name ? (const char *)name : e2->name);
}

struct collection_status {
        enum { FROM_WORKTREE = 0, FROM_INDEX = 1 } mode;

        const char *reference;

        unsigned skip_unseen:1;
        size_t unmerged_count, binary_count;
        struct string_list *files;
        struct hashmap file_map;
};

static void collect_changes_cb(struct diff_queue_struct *q,
                               struct diff_options *options,
                               void *data)
{
        struct collection_status *s = data;
        struct diffstat_t stat = { 0 };
        int i;

        if (!q->nr)
                return;

        compute_diffstat(options, &stat, q);

        for (i = 0; i < stat.nr; i++) {
                const char *name = stat.files[i]->name;
                int hash = strhash(name);
                struct pathname_entry *entry;
                struct file_item *file_item;
                struct adddel *adddel, *other_adddel;

                entry = hashmap_get_entry_from_hash(&s->file_map, hash, name,
                                                    struct pathname_entry, ent);
                if (!entry) {
                        if (s->skip_unseen)
                                continue;

                        add_file_item(s->files, name);

                        CALLOC_ARRAY(entry, 1);
                        hashmap_entry_init(&entry->ent, hash);
                        entry->name = s->files->items[s->files->nr - 1].string;
                        entry->item = s->files->items[s->files->nr - 1].util;
                        hashmap_add(&s->file_map, &entry->ent);
                }

                file_item = entry->item;
                adddel = s->mode == FROM_INDEX ?
                        &file_item->index : &file_item->worktree;
                other_adddel = s->mode == FROM_INDEX ?
                        &file_item->worktree : &file_item->index;
                adddel->seen = 1;
                adddel->add = stat.files[i]->added;
                adddel->del = stat.files[i]->deleted;
                if (stat.files[i]->is_binary) {
                        if (!other_adddel->binary)
                                s->binary_count++;
                        adddel->binary = 1;
                }
                if (stat.files[i]->is_unmerged) {
                        if (!other_adddel->unmerged)
                                s->unmerged_count++;
                        adddel->unmerged = 1;
                }
        }
        free_diffstat_info(&stat);
}

enum modified_files_filter {
        NO_FILTER = 0,
        WORKTREE_ONLY = 1,
        INDEX_ONLY = 2,
};

static int get_modified_files(struct repository *r,
                              enum modified_files_filter filter,
                              struct prefix_item_list *files,
                              const struct pathspec *ps,
                              size_t *unmerged_count,
                              size_t *binary_count)
{
        struct object_id head_oid;
        int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING,
                                             &head_oid, NULL);
        struct collection_status s = { 0 };
        int i;

        if (discard_index(r->index) < 0 ||
            repo_read_index_preload(r, ps, 0) < 0)
                return error(_("could not read index"));

        prefix_item_list_clear(files);
        s.files = &files->items;
        hashmap_init(&s.file_map, pathname_entry_cmp, NULL, 0);

        for (i = 0; i < 2; i++) {
                struct rev_info rev;
                struct setup_revision_opt opt = { 0 };

                if (filter == INDEX_ONLY)
                        s.mode = (i == 0) ? FROM_INDEX : FROM_WORKTREE;
                else
                        s.mode = (i == 0) ? FROM_WORKTREE : FROM_INDEX;
                s.skip_unseen = filter && i;

                opt.def = is_initial ?
                        empty_tree_oid_hex() : oid_to_hex(&head_oid);

                init_revisions(&rev, NULL);
                setup_revisions(0, NULL, &rev, &opt);

                rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
                rev.diffopt.format_callback = collect_changes_cb;
                rev.diffopt.format_callback_data = &s;

                if (ps)
                        copy_pathspec(&rev.prune_data, ps);

                if (s.mode == FROM_INDEX)
                        run_diff_index(&rev, 1);
                else {
                        rev.diffopt.flags.ignore_dirty_submodules = 1;
                        run_diff_files(&rev, 0);
                }

                if (ps)
                        clear_pathspec(&rev.prune_data);
        }
        hashmap_clear_and_free(&s.file_map, struct pathname_entry, ent);
        if (unmerged_count)
                *unmerged_count = s.unmerged_count;
        if (binary_count)
                *binary_count = s.binary_count;

        /* While the diffs are ordered already, we ran *two* diffs... */
        string_list_sort(&files->items);

        return 0;
}

static void render_adddel(struct strbuf *buf,
                                struct adddel *ad, const char *no_changes)
{
        if (ad->binary)
                strbuf_addstr(buf, _("binary"));
        else if (ad->seen)
                strbuf_addf(buf, "+%"PRIuMAX"/-%"PRIuMAX,
                            (uintmax_t)ad->add, (uintmax_t)ad->del);
        else
                strbuf_addstr(buf, no_changes);
}

/* filters out prefixes which have special meaning to list_and_choose() */
static int is_valid_prefix(const char *prefix, size_t prefix_len)
{
        return prefix_len && prefix &&
                /*
                 * We expect `prefix` to be NUL terminated, therefore this
                 * `strcspn()` call is okay, even if it might do much more
                 * work than strictly necessary.
                 */
                strcspn(prefix, " \t\r\n,") >= prefix_len &&    /* separators */
                *prefix != '-' &&                               /* deselection */
                !isdigit(*prefix) &&                            /* selection */
                (prefix_len != 1 ||
                 (*prefix != '*' &&                             /* "all" wildcard */
                  *prefix != '?'));                             /* prompt help */
}

struct print_file_item_data {
        const char *modified_fmt, *color, *reset;
        struct strbuf buf, name, index, worktree;
        unsigned only_names:1;
};

static void print_file_item(int i, int selected, struct string_list_item *item,
                            void *print_file_item_data)
{
        struct file_item *c = item->util;
        struct print_file_item_data *d = print_file_item_data;
        const char *highlighted = NULL;

        strbuf_reset(&d->index);
        strbuf_reset(&d->worktree);
        strbuf_reset(&d->buf);

        /* Format the item with the prefix highlighted. */
        if (c->prefix_length > 0 &&
            is_valid_prefix(item->string, c->prefix_length)) {
                strbuf_reset(&d->name);
                strbuf_addf(&d->name, "%s%.*s%s%s", d->color,
                            (int)c->prefix_length, item->string, d->reset,
                            item->string + c->prefix_length);
                highlighted = d->name.buf;
        }

        if (d->only_names) {
                printf("%c%2d: %s", selected ? '*' : ' ', i + 1,
                       highlighted ? highlighted : item->string);
                return;
        }

        render_adddel(&d->worktree, &c->worktree, _("nothing"));
        render_adddel(&d->index, &c->index, _("unchanged"));

        strbuf_addf(&d->buf, d->modified_fmt, d->index.buf, d->worktree.buf,
                    highlighted ? highlighted : item->string);

        printf("%c%2d: %s", selected ? '*' : ' ', i + 1, d->buf.buf);
}

static int run_status(struct add_i_state *s, const struct pathspec *ps,
                      struct prefix_item_list *files,
                      struct list_and_choose_options *opts)
{
        if (get_modified_files(s->r, NO_FILTER, files, ps, NULL, NULL) < 0)
                return -1;

        list(s, &files->items, NULL, &opts->list_opts);
        putchar('\n');

        return 0;
}

static int run_update(struct add_i_state *s, const struct pathspec *ps,
                      struct prefix_item_list *files,
                      struct list_and_choose_options *opts)
{
        int res = 0, fd;
        size_t count, i;
        struct lock_file index_lock;

        if (get_modified_files(s->r, WORKTREE_ONLY, files, ps, NULL, NULL) < 0)
                return -1;

        if (!files->items.nr) {
                putchar('\n');
                return 0;
        }

        opts->prompt = N_("Update");
        count = list_and_choose(s, files, opts);
        if (count <= 0) {
                putchar('\n');
                return 0;
        }

        fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
        if (fd < 0) {
                putchar('\n');
                return -1;
        }

        for (i = 0; i < files->items.nr; i++) {
                const char *name = files->items.items[i].string;
                if (files->selected[i] &&
                    add_file_to_index(s->r->index, name, 0) < 0) {
                        res = error(_("could not stage '%s'"), name);
                        break;
                }
        }

        if (!res && write_locked_index(s->r->index, &index_lock, COMMIT_LOCK) < 0)
                res = error(_("could not write index"));

        if (!res)
                printf(Q_("updated %d path\n",
                          "updated %d paths\n", count), (int)count);

        putchar('\n');
        return res;
}

static void revert_from_diff(struct diff_queue_struct *q,
                             struct diff_options *opt, void *data)
{
        int i, add_flags = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;

        for (i = 0; i < q->nr; i++) {
                struct diff_filespec *one = q->queue[i]->one;
                struct cache_entry *ce;

                if (!(one->mode && !is_null_oid(&one->oid))) {
                        remove_file_from_index(opt->repo->index, one->path);
                        printf(_("note: %s is untracked now.\n"), one->path);
                } else {
                        ce = make_cache_entry(opt->repo->index, one->mode,
                                              &one->oid, one->path, 0, 0);
                        if (!ce)
                                die(_("make_cache_entry failed for path '%s'"),
                                    one->path);
                        add_index_entry(opt->repo->index, ce, add_flags);
                }
        }
}

static int run_revert(struct add_i_state *s, const struct pathspec *ps,
                      struct prefix_item_list *files,
                      struct list_and_choose_options *opts)
{
        int res = 0, fd;
        size_t count, i, j;

        struct object_id oid;
        int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &oid,
                                             NULL);
        struct lock_file index_lock;
        const char **paths;
        struct tree *tree;
        struct diff_options diffopt = { NULL };

        if (get_modified_files(s->r, INDEX_ONLY, files, ps, NULL, NULL) < 0)
                return -1;

        if (!files->items.nr) {
                putchar('\n');
                return 0;
        }

        opts->prompt = N_("Revert");
        count = list_and_choose(s, files, opts);
        if (count <= 0)
                goto finish_revert;

        fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
        if (fd < 0) {
                res = -1;
                goto finish_revert;
        }

        if (is_initial)
                oidcpy(&oid, s->r->hash_algo->empty_tree);
        else {
                tree = parse_tree_indirect(&oid);
                if (!tree) {
                        res = error(_("Could not parse HEAD^{tree}"));
                        goto finish_revert;
                }
                oidcpy(&oid, &tree->object.oid);
        }

        ALLOC_ARRAY(paths, count + 1);
        for (i = j = 0; i < files->items.nr; i++)
                if (files->selected[i])
                        paths[j++] = files->items.items[i].string;
        paths[j] = NULL;

        parse_pathspec(&diffopt.pathspec, 0,
                       PATHSPEC_PREFER_FULL | PATHSPEC_LITERAL_PATH,
                       NULL, paths);

        diffopt.output_format = DIFF_FORMAT_CALLBACK;
        diffopt.format_callback = revert_from_diff;
        diffopt.flags.override_submodule_config = 1;
        diffopt.repo = s->r;

        if (do_diff_cache(&oid, &diffopt))
                res = -1;
        else {
                diffcore_std(&diffopt);
                diff_flush(&diffopt);
        }
        free(paths);
        clear_pathspec(&diffopt.pathspec);

        if (!res && write_locked_index(s->r->index, &index_lock,
                                       COMMIT_LOCK) < 0)
                res = -1;
        else
                res = repo_refresh_and_write_index(s->r, REFRESH_QUIET, 0, 1,
                                                   NULL, NULL, NULL);

        if (!res)
                printf(Q_("reverted %d path\n",
                          "reverted %d paths\n", count), (int)count);

finish_revert:
        putchar('\n');
        return res;
}

static int get_untracked_files(struct repository *r,
                               struct prefix_item_list *files,
                               const struct pathspec *ps)
{
        struct dir_struct dir = { 0 };
        size_t i;
        struct strbuf buf = STRBUF_INIT;

        if (repo_read_index(r) < 0)
                return error(_("could not read index"));

        prefix_item_list_clear(files);
        setup_standard_excludes(&dir);
        add_pattern_list(&dir, EXC_CMDL, "--exclude option");
        fill_directory(&dir, r->index, ps);

        for (i = 0; i < dir.nr; i++) {
                struct dir_entry *ent = dir.entries[i];

                if (index_name_is_other(r->index, ent->name, ent->len)) {
                        strbuf_reset(&buf);
                        strbuf_add(&buf, ent->name, ent->len);
                        add_file_item(&files->items, buf.buf);
                }
        }

        strbuf_release(&buf);
        return 0;
}

static int run_add_untracked(struct add_i_state *s, const struct pathspec *ps,
                      struct prefix_item_list *files,
                      struct list_and_choose_options *opts)
{
        struct print_file_item_data *d = opts->list_opts.print_item_data;
        int res = 0, fd;
        size_t count, i;
        struct lock_file index_lock;

        if (get_untracked_files(s->r, files, ps) < 0)
                return -1;

        if (!files->items.nr) {
                printf(_("No untracked files.\n"));
                goto finish_add_untracked;
        }

        opts->prompt = N_("Add untracked");
        d->only_names = 1;
        count = list_and_choose(s, files, opts);
        d->only_names = 0;
        if (count <= 0)
                goto finish_add_untracked;

        fd = repo_hold_locked_index(s->r, &index_lock, LOCK_REPORT_ON_ERROR);
        if (fd < 0) {
                res = -1;
                goto finish_add_untracked;
        }

        for (i = 0; i < files->items.nr; i++) {
                const char *name = files->items.items[i].string;
                if (files->selected[i] &&
                    add_file_to_index(s->r->index, name, 0) < 0) {
                        res = error(_("could not stage '%s'"), name);
                        break;
                }
        }

        if (!res &&
            write_locked_index(s->r->index, &index_lock, COMMIT_LOCK) < 0)
                res = error(_("could not write index"));

        if (!res)
                printf(Q_("added %d path\n",
                          "added %d paths\n", count), (int)count);

finish_add_untracked:
        putchar('\n');
        return res;
}

static int run_patch(struct add_i_state *s, const struct pathspec *ps,
                     struct prefix_item_list *files,
                     struct list_and_choose_options *opts)
{
        int res = 0;
        ssize_t count, i, j;
        size_t unmerged_count = 0, binary_count = 0;

        if (get_modified_files(s->r, WORKTREE_ONLY, files, ps,
                               &unmerged_count, &binary_count) < 0)
                return -1;

        if (unmerged_count || binary_count) {
                for (i = j = 0; i < files->items.nr; i++) {
                        struct file_item *item = files->items.items[i].util;

                        if (item->index.binary || item->worktree.binary) {
                                free(item);
                                free(files->items.items[i].string);
                        } else if (item->index.unmerged ||
                                 item->worktree.unmerged) {
                                color_fprintf_ln(stderr, s->error_color,
                                                 _("ignoring unmerged: %s"),
                                                 files->items.items[i].string);
                                free(item);
                                free(files->items.items[i].string);
                        } else
                                files->items.items[j++] = files->items.items[i];
                }
                files->items.nr = j;
        }

        if (!files->items.nr) {
                if (binary_count)
                        fprintf(stderr, _("Only binary files changed.\n"));
                else
                        fprintf(stderr, _("No changes.\n"));
                return 0;
        }

        opts->prompt = N_("Patch update");
        count = list_and_choose(s, files, opts);
        if (count > 0) {
                struct strvec args = STRVEC_INIT;
                struct pathspec ps_selected = { 0 };

                for (i = 0; i < files->items.nr; i++)
                        if (files->selected[i])
                                strvec_push(&args,
                                            files->items.items[i].string);
                parse_pathspec(&ps_selected,
                               PATHSPEC_ALL_MAGIC & ~PATHSPEC_LITERAL,
                               PATHSPEC_LITERAL_PATH, "", args.v);
                res = run_add_p(s->r, ADD_P_ADD, NULL, &ps_selected);
                strvec_clear(&args);
                clear_pathspec(&ps_selected);
        }

        return res;
}

static int run_diff(struct add_i_state *s, const struct pathspec *ps,
                    struct prefix_item_list *files,
                    struct list_and_choose_options *opts)
{
        int res = 0;
        ssize_t count, i;

        struct object_id oid;
        int is_initial = !resolve_ref_unsafe("HEAD", RESOLVE_REF_READING, &oid,
                                             NULL);
        if (get_modified_files(s->r, INDEX_ONLY, files, ps, NULL, NULL) < 0)
                return -1;

        if (!files->items.nr) {
                putchar('\n');
                return 0;
        }

        opts->prompt = N_("Review diff");
        opts->flags = IMMEDIATE;
        count = list_and_choose(s, files, opts);
        opts->flags = 0;
        if (count > 0) {
                struct strvec args = STRVEC_INIT;

                strvec_pushl(&args, "git", "diff", "-p", "--cached",
                             oid_to_hex(!is_initial ? &oid :
                                        s->r->hash_algo->empty_tree),
                             "--", NULL);
                for (i = 0; i < files->items.nr; i++)
                        if (files->selected[i])
                                strvec_push(&args,
                                            files->items.items[i].string);
                res = run_command_v_opt(args.v, 0);
                strvec_clear(&args);
        }

        putchar('\n');
        return res;
}

static int run_help(struct add_i_state *s, const struct pathspec *unused_ps,
                    struct prefix_item_list *unused_files,
                    struct list_and_choose_options *unused_opts)
{
        color_fprintf_ln(stdout, s->help_color, "status        - %s",
                         _("show paths with changes"));
        color_fprintf_ln(stdout, s->help_color, "update        - %s",
                         _("add working tree state to the staged set of changes"));
        color_fprintf_ln(stdout, s->help_color, "revert        - %s",
                         _("revert staged set of changes back to the HEAD version"));
        color_fprintf_ln(stdout, s->help_color, "patch         - %s",
                         _("pick hunks and update selectively"));
        color_fprintf_ln(stdout, s->help_color, "diff          - %s",
                         _("view diff between HEAD and index"));
        color_fprintf_ln(stdout, s->help_color, "add untracked - %s",
                         _("add contents of untracked files to the staged set of changes"));

        return 0;
}

static void choose_prompt_help(struct add_i_state *s)
{
        color_fprintf_ln(stdout, s->help_color, "%s",
                         _("Prompt help:"));
        color_fprintf_ln(stdout, s->help_color, "1          - %s",
                         _("select a single item"));
        color_fprintf_ln(stdout, s->help_color, "3-5        - %s",
                         _("select a range of items"));
        color_fprintf_ln(stdout, s->help_color, "2-3,6-9    - %s",
                         _("select multiple ranges"));
        color_fprintf_ln(stdout, s->help_color, "foo        - %s",
                         _("select item based on unique prefix"));
        color_fprintf_ln(stdout, s->help_color, "-...       - %s",
                         _("unselect specified items"));
        color_fprintf_ln(stdout, s->help_color, "*          - %s",
                         _("choose all items"));
        color_fprintf_ln(stdout, s->help_color, "           - %s",
                         _("(empty) finish selecting"));
}

typedef int (*command_t)(struct add_i_state *s, const struct pathspec *ps,
                         struct prefix_item_list *files,
                         struct list_and_choose_options *opts);

struct command_item {
        size_t prefix_length;
        command_t command;
};

struct print_command_item_data {
        const char *color, *reset;
};

static void print_command_item(int i, int selected,
                               struct string_list_item *item,
                               void *print_command_item_data)
{
        struct print_command_item_data *d = print_command_item_data;
        struct command_item *util = item->util;

        if (!util->prefix_length ||
            !is_valid_prefix(item->string, util->prefix_length))
                printf(" %2d: %s", i + 1, item->string);
        else
                printf(" %2d: %s%.*s%s%s", i + 1,
                       d->color, (int)util->prefix_length, item->string,
                       d->reset, item->string + util->prefix_length);
}

static void command_prompt_help(struct add_i_state *s)
{
        const char *help_color = s->help_color;
        color_fprintf_ln(stdout, help_color, "%s", _("Prompt help:"));
        color_fprintf_ln(stdout, help_color, "1          - %s",
                         _("select a numbered item"));
        color_fprintf_ln(stdout, help_color, "foo        - %s",
                         _("select item based on unique prefix"));
        color_fprintf_ln(stdout, help_color, "           - %s",
                         _("(empty) select nothing"));
}

int run_add_i(struct repository *r, const struct pathspec *ps)
{
        struct add_i_state s = { NULL };
        struct print_command_item_data data = { "[", "]" };
        struct list_and_choose_options main_loop_opts = {
                { 4, N_("*** Commands ***"), print_command_item, &data },
                N_("What now"), SINGLETON | IMMEDIATE, command_prompt_help
        };
        struct {
                const char *string;
                command_t command;
        } command_list[] = {
                { "status", run_status },
                { "update", run_update },
                { "revert", run_revert },
                { "add untracked", run_add_untracked },
                { "patch", run_patch },
                { "diff", run_diff },
                { "quit", NULL },
                { "help", run_help },
        };
        struct prefix_item_list commands = PREFIX_ITEM_LIST_INIT;

        struct print_file_item_data print_file_item_data = {
                "%12s %12s %s", NULL, NULL,
                STRBUF_INIT, STRBUF_INIT, STRBUF_INIT, STRBUF_INIT
        };
        struct list_and_choose_options opts = {
                { 0, NULL, print_file_item, &print_file_item_data },
                NULL, 0, choose_prompt_help
        };
        struct strbuf header = STRBUF_INIT;
        struct prefix_item_list files = PREFIX_ITEM_LIST_INIT;
        ssize_t i;
        int res = 0;

        for (i = 0; i < ARRAY_SIZE(command_list); i++) {
                struct command_item *util = xcalloc(1, sizeof(*util));
                util->command = command_list[i].command;
                string_list_append(&commands.items, command_list[i].string)
                        ->util = util;
        }

        init_add_i_state(&s, r);

        /*
         * When color was asked for, use the prompt color for
         * highlighting, otherwise use square brackets.
         */
        if (s.use_color) {
                data.color = s.prompt_color;
                data.reset = s.reset_color;
        }
        print_file_item_data.color = data.color;
        print_file_item_data.reset = data.reset;

        strbuf_addstr(&header, "     ");
        strbuf_addf(&header, print_file_item_data.modified_fmt,
                    _("staged"), _("unstaged"), _("path"));
        opts.list_opts.header = header.buf;

        if (discard_index(r->index) < 0 ||
            repo_read_index(r) < 0 ||
            repo_refresh_and_write_index(r, REFRESH_QUIET, 0, 1,
                                         NULL, NULL, NULL) < 0)
                warning(_("could not refresh index"));

        res = run_status(&s, ps, &files, &opts);

        for (;;) {
                struct command_item *util;

                i = list_and_choose(&s, &commands, &main_loop_opts);
                if (i < 0 || i >= commands.items.nr)
                        util = NULL;
                else
                        util = commands.items.items[i].util;

                if (i == LIST_AND_CHOOSE_QUIT || (util && !util->command)) {
                        printf(_("Bye.\n"));
                        res = 0;
                        break;
                }

                if (util)
                        res = util->command(&s, ps, &files, &opts);
        }

        prefix_item_list_clear(&files);
        strbuf_release(&print_file_item_data.buf);
        strbuf_release(&print_file_item_data.name);
        strbuf_release(&print_file_item_data.index);
        strbuf_release(&print_file_item_data.worktree);
        strbuf_release(&header);
        prefix_item_list_clear(&commands);
        clear_add_i_state(&s);

        return res;
}