/*
 * Blame
 *
 * Copyright (c) 2006, 2014 by its authors
 * See COPYING for licensing conditions
 */

#include "cache.h"
#include "builtin.h"
#include "commit.h"
#include "diff.h"
#include "revision.h"
#include "quote.h"
#include "string-list.h"
#include "mailmap.h"
#include "parse-options.h"
#include "prio-queue.h"
#include "utf8.h"
#include "userdiff.h"
#include "line-range.h"
#include "line-log.h"
#include "dir.h"
#include "progress.h"
#include "blame.h"

static char blame_usage[] = N_("git blame [<options>] [<rev-opts>] [<rev>] [--] <file>");

static const char *blame_opt_usage[] = {
        blame_usage,
        "",
        N_("<rev-opts> are documented in git-rev-list(1)"),
        NULL
};

static int longest_file;
static int longest_author;
static int max_orig_digits;
static int max_digits;
static int max_score_digits;
static int show_root;
static int reverse;
static int blank_boundary;
static int incremental;
static int xdl_opts;
static int abbrev = -1;
static int no_whole_file_rename;
static int show_progress;

static struct date_mode blame_date_mode = { DATE_ISO8601 };
static size_t blame_date_width;

static struct string_list mailmap = STRING_LIST_INIT_NODUP;

#ifndef DEBUG
#define DEBUG 0
#endif

static unsigned blame_move_score;
static unsigned blame_copy_score;

/* Remember to update object flag allocation in object.h */
#define METAINFO_SHOWN          (1u<<12)
#define MORE_THAN_ONE_PATH      (1u<<13)

struct progress_info {
        struct progress *progress;
        int blamed_lines;
};

static const char *nth_line_cb(void *data, long lno)
{
        return blame_nth_line((struct blame_scoreboard *)data, lno);
}

/*
 * Information on commits, used for output.
 */
struct commit_info {
        struct strbuf author;
        struct strbuf author_mail;
        timestamp_t author_time;
        struct strbuf author_tz;

        /* filled only when asked for details */
        struct strbuf committer;
        struct strbuf committer_mail;
        timestamp_t committer_time;
        struct strbuf committer_tz;

        struct strbuf summary;
};

/*
 * Parse author/committer line in the commit object buffer
 */
static void get_ac_line(const char *inbuf, const char *what,
        struct strbuf *name, struct strbuf *mail,
        timestamp_t *time, struct strbuf *tz)
{
        struct ident_split ident;
        size_t len, maillen, namelen;
        char *tmp, *endp;
        const char *namebuf, *mailbuf;

        tmp = strstr(inbuf, what);
        if (!tmp)
                goto error_out;
        tmp += strlen(what);
        endp = strchr(tmp, '\n');
        if (!endp)
                len = strlen(tmp);
        else
                len = endp - tmp;

        if (split_ident_line(&ident, tmp, len)) {
        error_out:
                /* Ugh */
                tmp = "(unknown)";
                strbuf_addstr(name, tmp);
                strbuf_addstr(mail, tmp);
                strbuf_addstr(tz, tmp);
                *time = 0;
                return;
        }

        namelen = ident.name_end - ident.name_begin;
        namebuf = ident.name_begin;

        maillen = ident.mail_end - ident.mail_begin;
        mailbuf = ident.mail_begin;

        if (ident.date_begin && ident.date_end)
                *time = strtoul(ident.date_begin, NULL, 10);
        else
                *time = 0;

        if (ident.tz_begin && ident.tz_end)
                strbuf_add(tz, ident.tz_begin, ident.tz_end - ident.tz_begin);
        else
                strbuf_addstr(tz, "(unknown)");

        /*
         * Now, convert both name and e-mail using mailmap
         */
        map_user(&mailmap, &mailbuf, &maillen,
                 &namebuf, &namelen);

        strbuf_addf(mail, "<%.*s>", (int)maillen, mailbuf);
        strbuf_add(name, namebuf, namelen);
}

static void commit_info_init(struct commit_info *ci)
{

        strbuf_init(&ci->author, 0);
        strbuf_init(&ci->author_mail, 0);
        strbuf_init(&ci->author_tz, 0);
        strbuf_init(&ci->committer, 0);
        strbuf_init(&ci->committer_mail, 0);
        strbuf_init(&ci->committer_tz, 0);
        strbuf_init(&ci->summary, 0);
}

static void commit_info_destroy(struct commit_info *ci)
{

        strbuf_release(&ci->author);
        strbuf_release(&ci->author_mail);
        strbuf_release(&ci->author_tz);
        strbuf_release(&ci->committer);
        strbuf_release(&ci->committer_mail);
        strbuf_release(&ci->committer_tz);
        strbuf_release(&ci->summary);
}

static void get_commit_info(struct commit *commit,
                            struct commit_info *ret,
                            int detailed)
{
        int len;
        const char *subject, *encoding;
        const char *message;

        commit_info_init(ret);

        encoding = get_log_output_encoding();
        message = logmsg_reencode(commit, NULL, encoding);
        get_ac_line(message, "\nauthor ",
                    &ret->author, &ret->author_mail,
                    &ret->author_time, &ret->author_tz);

        if (!detailed) {
                unuse_commit_buffer(commit, message);
                return;
        }

        get_ac_line(message, "\ncommitter ",
                    &ret->committer, &ret->committer_mail,
                    &ret->committer_time, &ret->committer_tz);

        len = find_commit_subject(message, &subject);
        if (len)
                strbuf_add(&ret->summary, subject, len);
        else
                strbuf_addf(&ret->summary, "(%s)", oid_to_hex(&commit->object.oid));

        unuse_commit_buffer(commit, message);
}

/*
 * Write out any suspect information which depends on the path. This must be
 * handled separately from emit_one_suspect_detail(), because a given commit
 * may have changes in multiple paths. So this needs to appear each time
 * we mention a new group.
 *
 * To allow LF and other nonportable characters in pathnames,
 * they are c-style quoted as needed.
 */
static void write_filename_info(struct blame_origin *suspect)
{
        if (suspect->previous) {
                struct blame_origin *prev = suspect->previous;
                printf("previous %s ", oid_to_hex(&prev->commit->object.oid));
                write_name_quoted(prev->path, stdout, '\n');
        }
        printf("filename ");
        write_name_quoted(suspect->path, stdout, '\n');
}

/*
 * Porcelain/Incremental format wants to show a lot of details per
 * commit.  Instead of repeating this every line, emit it only once,
 * the first time each commit appears in the output (unless the
 * user has specifically asked for us to repeat).
 */
static int emit_one_suspect_detail(struct blame_origin *suspect, int repeat)
{
        struct commit_info ci;

        if (!repeat && (suspect->commit->object.flags & METAINFO_SHOWN))
                return 0;

        suspect->commit->object.flags |= METAINFO_SHOWN;
        get_commit_info(suspect->commit, &ci, 1);
        printf("author %s\n", ci.author.buf);
        printf("author-mail %s\n", ci.author_mail.buf);
        printf("author-time %"PRItime"\n", ci.author_time);
        printf("author-tz %s\n", ci.author_tz.buf);
        printf("committer %s\n", ci.committer.buf);
        printf("committer-mail %s\n", ci.committer_mail.buf);
        printf("committer-time %"PRItime"\n", ci.committer_time);
        printf("committer-tz %s\n", ci.committer_tz.buf);
        printf("summary %s\n", ci.summary.buf);
        if (suspect->commit->object.flags & UNINTERESTING)
                printf("boundary\n");

        commit_info_destroy(&ci);

        return 1;
}

/*
 * The blame_entry is found to be guilty for the range.
 * Show it in incremental output.
 */
static void found_guilty_entry(struct blame_entry *ent, void *data)
{
        struct progress_info *pi = (struct progress_info *)data;

        if (incremental) {
                struct blame_origin *suspect = ent->suspect;

                printf("%s %d %d %d\n",
                       oid_to_hex(&suspect->commit->object.oid),
                       ent->s_lno + 1, ent->lno + 1, ent->num_lines);
                emit_one_suspect_detail(suspect, 0);
                write_filename_info(suspect);
                maybe_flush_or_die(stdout, "stdout");
        }
        pi->blamed_lines += ent->num_lines;
        display_progress(pi->progress, pi->blamed_lines);
}

static const char *format_time(timestamp_t time, const char *tz_str,
                               int show_raw_time)
{
        static struct strbuf time_buf = STRBUF_INIT;

        strbuf_reset(&time_buf);
        if (show_raw_time) {
                strbuf_addf(&time_buf, "%"PRItime" %s", time, tz_str);
        }
        else {
                const char *time_str;
                size_t time_width;
                int tz;
                tz = atoi(tz_str);
                time_str = show_date(time, tz, &blame_date_mode);
                strbuf_addstr(&time_buf, time_str);
                /*
                 * Add space paddings to time_buf to display a fixed width
                 * string, and use time_width for display width calibration.
                 */
                for (time_width = utf8_strwidth(time_str);
                     time_width < blame_date_width;
                     time_width++)
                        strbuf_addch(&time_buf, ' ');
        }
        return time_buf.buf;
}

#define OUTPUT_ANNOTATE_COMPAT  001
#define OUTPUT_LONG_OBJECT_NAME 002
#define OUTPUT_RAW_TIMESTAMP    004
#define OUTPUT_PORCELAIN        010
#define OUTPUT_SHOW_NAME        020
#define OUTPUT_SHOW_NUMBER      040
#define OUTPUT_SHOW_SCORE      0100
#define OUTPUT_NO_AUTHOR       0200
#define OUTPUT_SHOW_EMAIL       0400
#define OUTPUT_LINE_PORCELAIN 01000

static void emit_porcelain_details(struct blame_origin *suspect, int repeat)
{
        if (emit_one_suspect_detail(suspect, repeat) ||
            (suspect->commit->object.flags & MORE_THAN_ONE_PATH))
                write_filename_info(suspect);
}

static void emit_porcelain(struct blame_scoreboard *sb, struct blame_entry *ent,
                           int opt)
{
        int repeat = opt & OUTPUT_LINE_PORCELAIN;
        int cnt;
        const char *cp;
        struct blame_origin *suspect = ent->suspect;
        char hex[GIT_MAX_HEXSZ + 1];

        oid_to_hex_r(hex, &suspect->commit->object.oid);
        printf("%s %d %d %d\n",
               hex,
               ent->s_lno + 1,
               ent->lno + 1,
               ent->num_lines);
        emit_porcelain_details(suspect, repeat);

        cp = blame_nth_line(sb, ent->lno);
        for (cnt = 0; cnt < ent->num_lines; cnt++) {
                char ch;
                if (cnt) {
                        printf("%s %d %d\n", hex,
                               ent->s_lno + 1 + cnt,
                               ent->lno + 1 + cnt);
                        if (repeat)
                                emit_porcelain_details(suspect, 1);
                }
                putchar('\t');
                do {
                        ch = *cp++;
                        putchar(ch);
                } while (ch != '\n' &&
                         cp < sb->final_buf + sb->final_buf_size);
        }

        if (sb->final_buf_size && cp[-1] != '\n')
                putchar('\n');
}

static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int opt)
{
        int cnt;
        const char *cp;
        struct blame_origin *suspect = ent->suspect;
        struct commit_info ci;
        char hex[GIT_MAX_HEXSZ + 1];
        int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);

        get_commit_info(suspect->commit, &ci, 1);
        oid_to_hex_r(hex, &suspect->commit->object.oid);

        cp = blame_nth_line(sb, ent->lno);
        for (cnt = 0; cnt < ent->num_lines; cnt++) {
                char ch;
                int length = (opt & OUTPUT_LONG_OBJECT_NAME) ? GIT_SHA1_HEXSZ : abbrev;

                if (suspect->commit->object.flags & UNINTERESTING) {
                        if (blank_boundary)
                                memset(hex, ' ', length);
                        else if (!(opt & OUTPUT_ANNOTATE_COMPAT)) {
                                length--;
                                putchar('^');
                        }
                }

                printf("%.*s", length, hex);
                if (opt & OUTPUT_ANNOTATE_COMPAT) {
                        const char *name;
                        if (opt & OUTPUT_SHOW_EMAIL)
                                name = ci.author_mail.buf;
                        else
                                name = ci.author.buf;
                        printf("\t(%10s\t%10s\t%d)", name,
                               format_time(ci.author_time, ci.author_tz.buf,
                                           show_raw_time),
                               ent->lno + 1 + cnt);
                } else {
                        if (opt & OUTPUT_SHOW_SCORE)
                                printf(" %*d %02d",
                                       max_score_digits, ent->score,
                                       ent->suspect->refcnt);
                        if (opt & OUTPUT_SHOW_NAME)
                                printf(" %-*.*s", longest_file, longest_file,
                                       suspect->path);
                        if (opt & OUTPUT_SHOW_NUMBER)
                                printf(" %*d", max_orig_digits,
                                       ent->s_lno + 1 + cnt);

                        if (!(opt & OUTPUT_NO_AUTHOR)) {
                                const char *name;
                                int pad;
                                if (opt & OUTPUT_SHOW_EMAIL)
                                        name = ci.author_mail.buf;
                                else
                                        name = ci.author.buf;
                                pad = longest_author - utf8_strwidth(name);
                                printf(" (%s%*s %10s",
                                       name, pad, "",
                                       format_time(ci.author_time,
                                                   ci.author_tz.buf,
                                                   show_raw_time));
                        }
                        printf(" %*d) ",
                               max_digits, ent->lno + 1 + cnt);
                }
                do {
                        ch = *cp++;
                        putchar(ch);
                } while (ch != '\n' &&
                         cp < sb->final_buf + sb->final_buf_size);
        }

        if (sb->final_buf_size && cp[-1] != '\n')
                putchar('\n');

        commit_info_destroy(&ci);
}

static void output(struct blame_scoreboard *sb, int option)
{
        struct blame_entry *ent;

        if (option & OUTPUT_PORCELAIN) {
                for (ent = sb->ent; ent; ent = ent->next) {
                        int count = 0;
                        struct blame_origin *suspect;
                        struct commit *commit = ent->suspect->commit;
                        if (commit->object.flags & MORE_THAN_ONE_PATH)
                                continue;
                        for (suspect = commit->util; suspect; suspect = suspect->next) {
                                if (suspect->guilty && count++) {
                                        commit->object.flags |= MORE_THAN_ONE_PATH;
                                        break;
                                }
                        }
                }
        }

        for (ent = sb->ent; ent; ent = ent->next) {
                if (option & OUTPUT_PORCELAIN)
                        emit_porcelain(sb, ent, option);
                else {
                        emit_other(sb, ent, option);
                }
        }
}

/*
 * Add phony grafts for use with -S; this is primarily to
 * support git's cvsserver that wants to give a linear history
 * to its clients.
 */
static int read_ancestry(const char *graft_file)
{
        FILE *fp = fopen(graft_file, "r");
        struct strbuf buf = STRBUF_INIT;
        if (!fp)
                return -1;
        while (!strbuf_getwholeline(&buf, fp, '\n')) {
                /* The format is just "Commit Parent1 Parent2 ...\n" */
                struct commit_graft *graft = read_graft_line(buf.buf, buf.len);
                if (graft)
                        register_commit_graft(graft, 0);
        }
        fclose(fp);
        strbuf_release(&buf);
        return 0;
}

static int update_auto_abbrev(int auto_abbrev, struct blame_origin *suspect)
{
        const char *uniq = find_unique_abbrev(suspect->commit->object.oid.hash,
                                              auto_abbrev);
        int len = strlen(uniq);
        if (auto_abbrev < len)
                return len;
        return auto_abbrev;
}

/*
 * How many columns do we need to show line numbers, authors,
 * and filenames?
 */
static void find_alignment(struct blame_scoreboard *sb, int *option)
{
        int longest_src_lines = 0;
        int longest_dst_lines = 0;
        unsigned largest_score = 0;
        struct blame_entry *e;
        int compute_auto_abbrev = (abbrev < 0);
        int auto_abbrev = DEFAULT_ABBREV;

        for (e = sb->ent; e; e = e->next) {
                struct blame_origin *suspect = e->suspect;
                int num;

                if (compute_auto_abbrev)
                        auto_abbrev = update_auto_abbrev(auto_abbrev, suspect);
                if (strcmp(suspect->path, sb->path))
                        *option |= OUTPUT_SHOW_NAME;
                num = strlen(suspect->path);
                if (longest_file < num)
                        longest_file = num;
                if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
                        struct commit_info ci;
                        suspect->commit->object.flags |= METAINFO_SHOWN;
                        get_commit_info(suspect->commit, &ci, 1);
                        if (*option & OUTPUT_SHOW_EMAIL)
                                num = utf8_strwidth(ci.author_mail.buf);
                        else
                                num = utf8_strwidth(ci.author.buf);
                        if (longest_author < num)
                                longest_author = num;
                        commit_info_destroy(&ci);
                }
                num = e->s_lno + e->num_lines;
                if (longest_src_lines < num)
                        longest_src_lines = num;
                num = e->lno + e->num_lines;
                if (longest_dst_lines < num)
                        longest_dst_lines = num;
                if (largest_score < blame_entry_score(sb, e))
                        largest_score = blame_entry_score(sb, e);
        }
        max_orig_digits = decimal_width(longest_src_lines);
        max_digits = decimal_width(longest_dst_lines);
        max_score_digits = decimal_width(largest_score);

        if (compute_auto_abbrev)
                /* one more abbrev length is needed for the boundary commit */
                abbrev = auto_abbrev + 1;
}

static void sanity_check_on_fail(struct blame_scoreboard *sb, int baa)
{
        int opt = OUTPUT_SHOW_SCORE | OUTPUT_SHOW_NUMBER | OUTPUT_SHOW_NAME;
        find_alignment(sb, &opt);
        output(sb, opt);
        die("Baa %d!", baa);
}

static unsigned parse_score(const char *arg)
{
        char *end;
        unsigned long score = strtoul(arg, &end, 10);
        if (*end)
                return 0;
        return score;
}

static const char *add_prefix(const char *prefix, const char *path)
{
        return prefix_path(prefix, prefix ? strlen(prefix) : 0, path);
}

static int git_blame_config(const char *var, const char *value, void *cb)
{
        if (!strcmp(var, "blame.showroot")) {
                show_root = git_config_bool(var, value);
                return 0;
        }
        if (!strcmp(var, "blame.blankboundary")) {
                blank_boundary = git_config_bool(var, value);
                return 0;
        }
        if (!strcmp(var, "blame.showemail")) {
                int *output_option = cb;
                if (git_config_bool(var, value))
                        *output_option |= OUTPUT_SHOW_EMAIL;
                else
                        *output_option &= ~OUTPUT_SHOW_EMAIL;
                return 0;
        }
        if (!strcmp(var, "blame.date")) {
                if (!value)
                        return config_error_nonbool(var);
                parse_date_format(value, &blame_date_mode);
                return 0;
        }

        if (git_diff_heuristic_config(var, value, cb) < 0)
                return -1;
        if (userdiff_config(var, value) < 0)
                return -1;

        return git_default_config(var, value, cb);
}

static int blame_copy_callback(const struct option *option, const char *arg, int unset)
{
        int *opt = option->value;

        /*
         * -C enables copy from removed files;
         * -C -C enables copy from existing files, but only
         *       when blaming a new file;
         * -C -C -C enables copy from existing files for
         *          everybody
         */
        if (*opt & PICKAXE_BLAME_COPY_HARDER)
                *opt |= PICKAXE_BLAME_COPY_HARDEST;
        if (*opt & PICKAXE_BLAME_COPY)
                *opt |= PICKAXE_BLAME_COPY_HARDER;
        *opt |= PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE;

        if (arg)
                blame_copy_score = parse_score(arg);
        return 0;
}

static int blame_move_callback(const struct option *option, const char *arg, int unset)
{
        int *opt = option->value;

        *opt |= PICKAXE_BLAME_MOVE;

        if (arg)
                blame_move_score = parse_score(arg);
        return 0;
}

struct blame_entry *blame_entry_prepend(struct blame_entry *head,
                                        long start, long end,
                                        struct blame_origin *o)
{
        struct blame_entry *new_head = xcalloc(1, sizeof(struct blame_entry));
        new_head->lno = start;
        new_head->num_lines = end - start;
        new_head->suspect = o;
        new_head->s_lno = start;
        new_head->next = head;
        blame_origin_incref(o);
        return new_head;
}

int cmd_blame(int argc, const char **argv, const char *prefix)
{
        struct rev_info revs;
        const char *path;
        struct blame_scoreboard sb;
        struct blame_origin *o;
        struct blame_entry *ent = NULL;
        long dashdash_pos, lno;
        struct progress_info pi = { NULL, 0 };

        struct string_list range_list = STRING_LIST_INIT_NODUP;
        int output_option = 0, opt = 0;
        int show_stats = 0;
        const char *revs_file = NULL;
        const char *contents_from = NULL;
        const struct option options[] = {
                OPT_BOOL(0, "incremental", &incremental, N_("Show blame entries as we find them, incrementally")),
                OPT_BOOL('b', NULL, &blank_boundary, N_("Show blank SHA-1 for boundary commits (Default: off)")),
                OPT_BOOL(0, "root", &show_root, N_("Do not treat root commits as boundaries (Default: off)")),
                OPT_BOOL(0, "show-stats", &show_stats, N_("Show work cost statistics")),
                OPT_BOOL(0, "progress", &show_progress, N_("Force progress reporting")),
                OPT_BIT(0, "score-debug", &output_option, N_("Show output score for blame entries"), OUTPUT_SHOW_SCORE),
                OPT_BIT('f', "show-name", &output_option, N_("Show original filename (Default: auto)"), OUTPUT_SHOW_NAME),
                OPT_BIT('n', "show-number", &output_option, N_("Show original linenumber (Default: off)"), OUTPUT_SHOW_NUMBER),
                OPT_BIT('p', "porcelain", &output_option, N_("Show in a format designed for machine consumption"), OUTPUT_PORCELAIN),
                OPT_BIT(0, "line-porcelain", &output_option, N_("Show porcelain format with per-line commit information"), OUTPUT_PORCELAIN|OUTPUT_LINE_PORCELAIN),
                OPT_BIT('c', NULL, &output_option, N_("Use the same output mode as git-annotate (Default: off)"), OUTPUT_ANNOTATE_COMPAT),
                OPT_BIT('t', NULL, &output_option, N_("Show raw timestamp (Default: off)"), OUTPUT_RAW_TIMESTAMP),
                OPT_BIT('l', NULL, &output_option, N_("Show long commit SHA1 (Default: off)"), OUTPUT_LONG_OBJECT_NAME),
                OPT_BIT('s', NULL, &output_option, N_("Suppress author name and timestamp (Default: off)"), OUTPUT_NO_AUTHOR),
                OPT_BIT('e', "show-email", &output_option, N_("Show author email instead of name (Default: off)"), OUTPUT_SHOW_EMAIL),
                OPT_BIT('w', NULL, &xdl_opts, N_("Ignore whitespace differences"), XDF_IGNORE_WHITESPACE),

                /*
                 * The following two options are parsed by parse_revision_opt()
                 * and are only included here to get included in the "-h"
                 * output:
                 */
                { OPTION_LOWLEVEL_CALLBACK, 0, "indent-heuristic", NULL, NULL, N_("Use an experimental heuristic to improve diffs"), PARSE_OPT_NOARG, parse_opt_unknown_cb },

                OPT_BIT(0, "minimal", &xdl_opts, N_("Spend extra cycles to find better match"), XDF_NEED_MINIMAL),
                OPT_STRING('S', NULL, &revs_file, N_("file"), N_("Use revisions from <file> instead of calling git-rev-list")),
                OPT_STRING(0, "contents", &contents_from, N_("file"), N_("Use <file>'s contents as the final image")),
                { OPTION_CALLBACK, 'C', NULL, &opt, N_("score"), N_("Find line copies within and across files"), PARSE_OPT_OPTARG, blame_copy_callback },
                { OPTION_CALLBACK, 'M', NULL, &opt, N_("score"), N_("Find line movements within and across files"), PARSE_OPT_OPTARG, blame_move_callback },
                OPT_STRING_LIST('L', NULL, &range_list, N_("n,m"), N_("Process only line range n,m, counting from 1")),
                OPT__ABBREV(&abbrev),
                OPT_END()
        };

        struct parse_opt_ctx_t ctx;
        int cmd_is_annotate = !strcmp(argv[0], "annotate");
        struct range_set ranges;
        unsigned int range_i;
        long anchor;

        git_config(git_blame_config, &output_option);
        init_revisions(&revs, NULL);
        revs.date_mode = blame_date_mode;
        DIFF_OPT_SET(&revs.diffopt, ALLOW_TEXTCONV);
        DIFF_OPT_SET(&revs.diffopt, FOLLOW_RENAMES);

        save_commit_buffer = 0;
        dashdash_pos = 0;
        show_progress = -1;

        parse_options_start(&ctx, argc, argv, prefix, options,
                            PARSE_OPT_KEEP_DASHDASH | PARSE_OPT_KEEP_ARGV0);
        for (;;) {
                switch (parse_options_step(&ctx, options, blame_opt_usage)) {
                case PARSE_OPT_HELP:
                        exit(129);
                case PARSE_OPT_DONE:
                        if (ctx.argv[0])
                                dashdash_pos = ctx.cpidx;
                        goto parse_done;
                }

                if (!strcmp(ctx.argv[0], "--reverse")) {
                        ctx.argv[0] = "--children";
                        reverse = 1;
                }
                parse_revision_opt(&revs, &ctx, options, blame_opt_usage);
        }
parse_done:
        no_whole_file_rename = !DIFF_OPT_TST(&revs.diffopt, FOLLOW_RENAMES);
        xdl_opts |= revs.diffopt.xdl_opts & XDF_INDENT_HEURISTIC;
        DIFF_OPT_CLR(&revs.diffopt, FOLLOW_RENAMES);
        argc = parse_options_end(&ctx);

        if (incremental || (output_option & OUTPUT_PORCELAIN)) {
                if (show_progress > 0)
                        die(_("--progress can't be used with --incremental or porcelain formats"));
                show_progress = 0;
        } else if (show_progress < 0)
                show_progress = isatty(2);

        if (0 < abbrev && abbrev < GIT_SHA1_HEXSZ)
                /* one more abbrev length is needed for the boundary commit */
                abbrev++;
        else if (!abbrev)
                abbrev = GIT_SHA1_HEXSZ;

        if (revs_file && read_ancestry(revs_file))
                die_errno("reading graft file '%s' failed", revs_file);

        if (cmd_is_annotate) {
                output_option |= OUTPUT_ANNOTATE_COMPAT;
                blame_date_mode.type = DATE_ISO8601;
        } else {
                blame_date_mode = revs.date_mode;
        }

        /* The maximum width used to show the dates */
        switch (blame_date_mode.type) {
        case DATE_RFC2822:
                blame_date_width = sizeof("Thu, 19 Oct 2006 16:00:04 -0700");
                break;
        case DATE_ISO8601_STRICT:
                blame_date_width = sizeof("2006-10-19T16:00:04-07:00");
                break;
        case DATE_ISO8601:
                blame_date_width = sizeof("2006-10-19 16:00:04 -0700");
                break;
        case DATE_RAW:
                blame_date_width = sizeof("1161298804 -0700");
                break;
        case DATE_UNIX:
                blame_date_width = sizeof("1161298804");
                break;
        case DATE_SHORT:
                blame_date_width = sizeof("2006-10-19");
                break;
        case DATE_RELATIVE:
                /* TRANSLATORS: This string is used to tell us the maximum
                   display width for a relative timestamp in "git blame"
                   output.  For C locale, "4 years, 11 months ago", which
                   takes 22 places, is the longest among various forms of
                   relative timestamps, but your language may need more or
                   fewer display columns. */
                blame_date_width = utf8_strwidth(_("4 years, 11 months ago")) + 1; /* add the null */
                break;
        case DATE_NORMAL:
                blame_date_width = sizeof("Thu Oct 19 16:00:04 2006 -0700");
                break;
        case DATE_STRFTIME:
                blame_date_width = strlen(show_date(0, 0, &blame_date_mode)) + 1; /* add the null */
                break;
        }
        blame_date_width -= 1; /* strip the null */

        if (DIFF_OPT_TST(&revs.diffopt, FIND_COPIES_HARDER))
                opt |= (PICKAXE_BLAME_COPY | PICKAXE_BLAME_MOVE |
                        PICKAXE_BLAME_COPY_HARDER);

        /*
         * We have collected options unknown to us in argv[1..unk]
         * which are to be passed to revision machinery if we are
         * going to do the "bottom" processing.
         *
         * The remaining are:
         *
         * (1) if dashdash_pos != 0, it is either
         *     "blame [revisions] -- <path>" or
         *     "blame -- <path> <rev>"
         *
         * (2) otherwise, it is one of the two:
         *     "blame [revisions] <path>"
         *     "blame <path> <rev>"
         *
         * Note that we must strip out <path> from the arguments: we do not
         * want the path pruning but we may want "bottom" processing.
         */
        if (dashdash_pos) {
                switch (argc - dashdash_pos - 1) {
                case 2: /* (1b) */
                        if (argc != 4)
                                usage_with_options(blame_opt_usage, options);
                        /* reorder for the new way: <rev> -- <path> */
                        argv[1] = argv[3];
                        argv[3] = argv[2];
                        argv[2] = "--";
                        /* FALLTHROUGH */
                case 1: /* (1a) */
                        path = add_prefix(prefix, argv[--argc]);
                        argv[argc] = NULL;
                        break;
                default:
                        usage_with_options(blame_opt_usage, options);
                }
        } else {
                if (argc < 2)
                        usage_with_options(blame_opt_usage, options);
                path = add_prefix(prefix, argv[argc - 1]);
                if (argc == 3 && !file_exists(path)) { /* (2b) */
                        path = add_prefix(prefix, argv[1]);
                        argv[1] = argv[2];
                }
                argv[argc - 1] = "--";

                setup_work_tree();
                if (!file_exists(path))
                        die_errno("cannot stat path '%s'", path);
        }

        revs.disable_stdin = 1;
        setup_revisions(argc, argv, &revs, NULL);

        init_scoreboard(&sb);
        sb.revs = &revs;
        sb.contents_from = contents_from;
        sb.reverse = reverse;
        setup_scoreboard(&sb, path, &o);
        lno = sb.num_lines;

        if (lno && !range_list.nr)
                string_list_append(&range_list, "1");

        anchor = 1;
        range_set_init(&ranges, range_list.nr);
        for (range_i = 0; range_i < range_list.nr; ++range_i) {
                long bottom, top;
                if (parse_range_arg(range_list.items[range_i].string,
                                    nth_line_cb, &sb, lno, anchor,
                                    &bottom, &top, sb.path))
                        usage(blame_usage);
                if (lno < top || ((lno || bottom) && lno < bottom))
                        die(Q_("file %s has only %lu line",
                               "file %s has only %lu lines",
                               lno), path, lno);
                if (bottom < 1)
                        bottom = 1;
                if (top < 1)
                        top = lno;
                bottom--;
                range_set_append_unsafe(&ranges, bottom, top);
                anchor = top + 1;
        }
        sort_and_merge_range_set(&ranges);

        for (range_i = ranges.nr; range_i > 0; --range_i) {
                const struct range *r = &ranges.ranges[range_i - 1];
                ent = blame_entry_prepend(ent, r->start, r->end, o);
        }

        o->suspects = ent;
        prio_queue_put(&sb.commits, o->commit);

        blame_origin_decref(o);

        range_set_release(&ranges);
        string_list_clear(&range_list, 0);

        sb.ent = NULL;
        sb.path = path;

        if (blame_move_score)
                sb.move_score = blame_move_score;
        if (blame_copy_score)
                sb.copy_score = blame_copy_score;

        sb.debug = DEBUG;
        sb.on_sanity_fail = &sanity_check_on_fail;

        sb.show_root = show_root;
        sb.xdl_opts = xdl_opts;
        sb.no_whole_file_rename = no_whole_file_rename;

        read_mailmap(&mailmap, NULL);

        sb.found_guilty_entry = &found_guilty_entry;
        sb.found_guilty_entry_data = &pi;
        if (show_progress)
                pi.progress = start_progress_delay(_("Blaming lines"),
                                                   sb.num_lines, 50, 1);

        assign_blame(&sb, opt);

        stop_progress(&pi.progress);

        if (!incremental)
                setup_pager();
        else
                return 0;

        blame_sort_final(&sb);

        blame_coalesce(&sb);

        if (!(output_option & OUTPUT_PORCELAIN))
                find_alignment(&sb, &output_option);

        output(&sb, output_option);
        free((void *)sb.final_buf);
        for (ent = sb.ent; ent; ) {
                struct blame_entry *e = ent->next;
                free(ent);
                ent = e;
        }

        if (show_stats) {
                printf("num read blob: %d\n", sb.num_read_blob);
                printf("num get patch: %d\n", sb.num_get_patch);
                printf("num commits: %d\n", sb.num_commits);
        }
        return 0;
}