Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "string-list.h"
   3#include "run-command.h"
   4#include "commit.h"
   5#include "trailer.h"
   6/*
   7 * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
   8 */
   9
  10enum action_where { WHERE_END, WHERE_AFTER, WHERE_BEFORE, WHERE_START };
  11enum action_if_exists { EXISTS_ADD_IF_DIFFERENT_NEIGHBOR, EXISTS_ADD_IF_DIFFERENT,
  12                        EXISTS_ADD, EXISTS_REPLACE, EXISTS_DO_NOTHING };
  13enum action_if_missing { MISSING_ADD, MISSING_DO_NOTHING };
  14
  15struct conf_info {
  16        char *name;
  17        char *key;
  18        char *command;
  19        enum action_where where;
  20        enum action_if_exists if_exists;
  21        enum action_if_missing if_missing;
  22};
  23
  24static struct conf_info default_conf_info;
  25
  26struct trailer_item {
  27        struct trailer_item *previous;
  28        struct trailer_item *next;
  29        const char *token;
  30        const char *value;
  31        struct conf_info conf;
  32};
  33
  34static struct trailer_item *first_conf_item;
  35
  36static char *separators = ":";
  37
  38#define TRAILER_ARG_STRING "$ARG"
  39
  40static int after_or_end(enum action_where where)
  41{
  42        return (where == WHERE_AFTER) || (where == WHERE_END);
  43}
  44
  45/*
  46 * Return the length of the string not including any final
  47 * punctuation. E.g., the input "Signed-off-by:" would return
  48 * 13, stripping the trailing punctuation but retaining
  49 * internal punctuation.
  50 */
  51static size_t token_len_without_separator(const char *token, size_t len)
  52{
  53        while (len > 0 && !isalnum(token[len - 1]))
  54                len--;
  55        return len;
  56}
  57
  58static int same_token(struct trailer_item *a, struct trailer_item *b)
  59{
  60        size_t a_len = token_len_without_separator(a->token, strlen(a->token));
  61        size_t b_len = token_len_without_separator(b->token, strlen(b->token));
  62        size_t min_len = (a_len > b_len) ? b_len : a_len;
  63
  64        return !strncasecmp(a->token, b->token, min_len);
  65}
  66
  67static int same_value(struct trailer_item *a, struct trailer_item *b)
  68{
  69        return !strcasecmp(a->value, b->value);
  70}
  71
  72static int same_trailer(struct trailer_item *a, struct trailer_item *b)
  73{
  74        return same_token(a, b) && same_value(a, b);
  75}
  76
  77static inline int contains_only_spaces(const char *str)
  78{
  79        const char *s = str;
  80        while (*s && isspace(*s))
  81                s++;
  82        return !*s;
  83}
  84
  85static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
  86{
  87        const char *ptr = strstr(sb->buf, a);
  88        if (ptr)
  89                strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
  90}
  91
  92static void free_trailer_item(struct trailer_item *item)
  93{
  94        free(item->conf.name);
  95        free(item->conf.key);
  96        free(item->conf.command);
  97        free((char *)item->token);
  98        free((char *)item->value);
  99        free(item);
 100}
 101
 102static char last_non_space_char(const char *s)
 103{
 104        int i;
 105        for (i = strlen(s) - 1; i >= 0; i--)
 106                if (!isspace(s[i]))
 107                        return s[i];
 108        return '\0';
 109}
 110
 111static void print_tok_val(const char *tok, const char *val)
 112{
 113        char c = last_non_space_char(tok);
 114        if (!c)
 115                return;
 116        if (strchr(separators, c))
 117                printf("%s%s\n", tok, val);
 118        else
 119                printf("%s%c %s\n", tok, separators[0], val);
 120}
 121
 122static void print_all(struct trailer_item *first, int trim_empty)
 123{
 124        struct trailer_item *item;
 125        for (item = first; item; item = item->next) {
 126                if (!trim_empty || strlen(item->value) > 0)
 127                        print_tok_val(item->token, item->value);
 128        }
 129}
 130
 131static void update_last(struct trailer_item **last)
 132{
 133        if (*last)
 134                while ((*last)->next != NULL)
 135                        *last = (*last)->next;
 136}
 137
 138static void update_first(struct trailer_item **first)
 139{
 140        if (*first)
 141                while ((*first)->previous != NULL)
 142                        *first = (*first)->previous;
 143}
 144
 145static void add_arg_to_input_list(struct trailer_item *on_tok,
 146                                  struct trailer_item *arg_tok,
 147                                  struct trailer_item **first,
 148                                  struct trailer_item **last)
 149{
 150        if (after_or_end(arg_tok->conf.where)) {
 151                arg_tok->next = on_tok->next;
 152                on_tok->next = arg_tok;
 153                arg_tok->previous = on_tok;
 154                if (arg_tok->next)
 155                        arg_tok->next->previous = arg_tok;
 156                update_last(last);
 157        } else {
 158                arg_tok->previous = on_tok->previous;
 159                on_tok->previous = arg_tok;
 160                arg_tok->next = on_tok;
 161                if (arg_tok->previous)
 162                        arg_tok->previous->next = arg_tok;
 163                update_first(first);
 164        }
 165}
 166
 167static int check_if_different(struct trailer_item *in_tok,
 168                              struct trailer_item *arg_tok,
 169                              int check_all)
 170{
 171        enum action_where where = arg_tok->conf.where;
 172        do {
 173                if (!in_tok)
 174                        return 1;
 175                if (same_trailer(in_tok, arg_tok))
 176                        return 0;
 177                /*
 178                 * if we want to add a trailer after another one,
 179                 * we have to check those before this one
 180                 */
 181                in_tok = after_or_end(where) ? in_tok->previous : in_tok->next;
 182        } while (check_all);
 183        return 1;
 184}
 185
 186static void remove_from_list(struct trailer_item *item,
 187                             struct trailer_item **first,
 188                             struct trailer_item **last)
 189{
 190        struct trailer_item *next = item->next;
 191        struct trailer_item *previous = item->previous;
 192
 193        if (next) {
 194                item->next->previous = previous;
 195                item->next = NULL;
 196        } else if (last)
 197                *last = previous;
 198
 199        if (previous) {
 200                item->previous->next = next;
 201                item->previous = NULL;
 202        } else if (first)
 203                *first = next;
 204}
 205
 206static struct trailer_item *remove_first(struct trailer_item **first)
 207{
 208        struct trailer_item *item = *first;
 209        *first = item->next;
 210        if (item->next) {
 211                item->next->previous = NULL;
 212                item->next = NULL;
 213        }
 214        return item;
 215}
 216
 217static const char *apply_command(const char *command, const char *arg)
 218{
 219        struct strbuf cmd = STRBUF_INIT;
 220        struct strbuf buf = STRBUF_INIT;
 221        struct child_process cp = CHILD_PROCESS_INIT;
 222        const char *argv[] = {NULL, NULL};
 223        const char *result;
 224
 225        strbuf_addstr(&cmd, command);
 226        if (arg)
 227                strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 228
 229        argv[0] = cmd.buf;
 230        cp.argv = argv;
 231        cp.env = local_repo_env;
 232        cp.no_stdin = 1;
 233        cp.use_shell = 1;
 234
 235        if (capture_command(&cp, &buf, 1024)) {
 236                error("running trailer command '%s' failed", cmd.buf);
 237                strbuf_release(&buf);
 238                result = xstrdup("");
 239        } else {
 240                strbuf_trim(&buf);
 241                result = strbuf_detach(&buf, NULL);
 242        }
 243
 244        strbuf_release(&cmd);
 245        return result;
 246}
 247
 248static void apply_item_command(struct trailer_item *in_tok, struct trailer_item *arg_tok)
 249{
 250        if (arg_tok->conf.command) {
 251                const char *arg;
 252                if (arg_tok->value && arg_tok->value[0]) {
 253                        arg = arg_tok->value;
 254                } else {
 255                        if (in_tok && in_tok->value)
 256                                arg = xstrdup(in_tok->value);
 257                        else
 258                                arg = xstrdup("");
 259                }
 260                arg_tok->value = apply_command(arg_tok->conf.command, arg);
 261                free((char *)arg);
 262        }
 263}
 264
 265static void apply_arg_if_exists(struct trailer_item *in_tok,
 266                                struct trailer_item *arg_tok,
 267                                struct trailer_item *on_tok,
 268                                struct trailer_item **in_tok_first,
 269                                struct trailer_item **in_tok_last)
 270{
 271        switch (arg_tok->conf.if_exists) {
 272        case EXISTS_DO_NOTHING:
 273                free_trailer_item(arg_tok);
 274                break;
 275        case EXISTS_REPLACE:
 276                apply_item_command(in_tok, arg_tok);
 277                add_arg_to_input_list(on_tok, arg_tok,
 278                                      in_tok_first, in_tok_last);
 279                remove_from_list(in_tok, in_tok_first, in_tok_last);
 280                free_trailer_item(in_tok);
 281                break;
 282        case EXISTS_ADD:
 283                apply_item_command(in_tok, arg_tok);
 284                add_arg_to_input_list(on_tok, arg_tok,
 285                                      in_tok_first, in_tok_last);
 286                break;
 287        case EXISTS_ADD_IF_DIFFERENT:
 288                apply_item_command(in_tok, arg_tok);
 289                if (check_if_different(in_tok, arg_tok, 1))
 290                        add_arg_to_input_list(on_tok, arg_tok,
 291                                              in_tok_first, in_tok_last);
 292                else
 293                        free_trailer_item(arg_tok);
 294                break;
 295        case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 296                apply_item_command(in_tok, arg_tok);
 297                if (check_if_different(on_tok, arg_tok, 0))
 298                        add_arg_to_input_list(on_tok, arg_tok,
 299                                              in_tok_first, in_tok_last);
 300                else
 301                        free_trailer_item(arg_tok);
 302                break;
 303        }
 304}
 305
 306static void apply_arg_if_missing(struct trailer_item **in_tok_first,
 307                                 struct trailer_item **in_tok_last,
 308                                 struct trailer_item *arg_tok)
 309{
 310        struct trailer_item **in_tok;
 311        enum action_where where;
 312
 313        switch (arg_tok->conf.if_missing) {
 314        case MISSING_DO_NOTHING:
 315                free_trailer_item(arg_tok);
 316                break;
 317        case MISSING_ADD:
 318                where = arg_tok->conf.where;
 319                in_tok = after_or_end(where) ? in_tok_last : in_tok_first;
 320                apply_item_command(NULL, arg_tok);
 321                if (*in_tok) {
 322                        add_arg_to_input_list(*in_tok, arg_tok,
 323                                              in_tok_first, in_tok_last);
 324                } else {
 325                        *in_tok_first = arg_tok;
 326                        *in_tok_last = arg_tok;
 327                }
 328                break;
 329        }
 330}
 331
 332static int find_same_and_apply_arg(struct trailer_item **in_tok_first,
 333                                   struct trailer_item **in_tok_last,
 334                                   struct trailer_item *arg_tok)
 335{
 336        struct trailer_item *in_tok;
 337        struct trailer_item *on_tok;
 338        struct trailer_item *following_tok;
 339
 340        enum action_where where = arg_tok->conf.where;
 341        int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 342        int backwards = after_or_end(where);
 343        struct trailer_item *start_tok = backwards ? *in_tok_last : *in_tok_first;
 344
 345        for (in_tok = start_tok; in_tok; in_tok = following_tok) {
 346                following_tok = backwards ? in_tok->previous : in_tok->next;
 347                if (!same_token(in_tok, arg_tok))
 348                        continue;
 349                on_tok = middle ? in_tok : start_tok;
 350                apply_arg_if_exists(in_tok, arg_tok, on_tok,
 351                                    in_tok_first, in_tok_last);
 352                return 1;
 353        }
 354        return 0;
 355}
 356
 357static void process_trailers_lists(struct trailer_item **in_tok_first,
 358                                   struct trailer_item **in_tok_last,
 359                                   struct trailer_item **arg_tok_first)
 360{
 361        struct trailer_item *arg_tok;
 362        struct trailer_item *next_arg;
 363
 364        if (!*arg_tok_first)
 365                return;
 366
 367        for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
 368                int applied = 0;
 369
 370                next_arg = arg_tok->next;
 371                remove_from_list(arg_tok, arg_tok_first, NULL);
 372
 373                applied = find_same_and_apply_arg(in_tok_first,
 374                                                  in_tok_last,
 375                                                  arg_tok);
 376
 377                if (!applied)
 378                        apply_arg_if_missing(in_tok_first,
 379                                             in_tok_last,
 380                                             arg_tok);
 381        }
 382}
 383
 384static int set_where(struct conf_info *item, const char *value)
 385{
 386        if (!strcasecmp("after", value))
 387                item->where = WHERE_AFTER;
 388        else if (!strcasecmp("before", value))
 389                item->where = WHERE_BEFORE;
 390        else if (!strcasecmp("end", value))
 391                item->where = WHERE_END;
 392        else if (!strcasecmp("start", value))
 393                item->where = WHERE_START;
 394        else
 395                return -1;
 396        return 0;
 397}
 398
 399static int set_if_exists(struct conf_info *item, const char *value)
 400{
 401        if (!strcasecmp("addIfDifferent", value))
 402                item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 403        else if (!strcasecmp("addIfDifferentNeighbor", value))
 404                item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 405        else if (!strcasecmp("add", value))
 406                item->if_exists = EXISTS_ADD;
 407        else if (!strcasecmp("replace", value))
 408                item->if_exists = EXISTS_REPLACE;
 409        else if (!strcasecmp("doNothing", value))
 410                item->if_exists = EXISTS_DO_NOTHING;
 411        else
 412                return -1;
 413        return 0;
 414}
 415
 416static int set_if_missing(struct conf_info *item, const char *value)
 417{
 418        if (!strcasecmp("doNothing", value))
 419                item->if_missing = MISSING_DO_NOTHING;
 420        else if (!strcasecmp("add", value))
 421                item->if_missing = MISSING_ADD;
 422        else
 423                return -1;
 424        return 0;
 425}
 426
 427static void duplicate_conf(struct conf_info *dst, struct conf_info *src)
 428{
 429        *dst = *src;
 430        if (src->name)
 431                dst->name = xstrdup(src->name);
 432        if (src->key)
 433                dst->key = xstrdup(src->key);
 434        if (src->command)
 435                dst->command = xstrdup(src->command);
 436}
 437
 438static struct trailer_item *get_conf_item(const char *name)
 439{
 440        struct trailer_item *item;
 441        struct trailer_item *previous;
 442
 443        /* Look up item with same name */
 444        for (previous = NULL, item = first_conf_item;
 445             item;
 446             previous = item, item = item->next) {
 447                if (!strcasecmp(item->conf.name, name))
 448                        return item;
 449        }
 450
 451        /* Item does not already exists, create it */
 452        item = xcalloc(sizeof(struct trailer_item), 1);
 453        duplicate_conf(&item->conf, &default_conf_info);
 454        item->conf.name = xstrdup(name);
 455
 456        if (!previous)
 457                first_conf_item = item;
 458        else {
 459                previous->next = item;
 460                item->previous = previous;
 461        }
 462
 463        return item;
 464}
 465
 466enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 467                         TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 468
 469static struct {
 470        const char *name;
 471        enum trailer_info_type type;
 472} trailer_config_items[] = {
 473        { "key", TRAILER_KEY },
 474        { "command", TRAILER_COMMAND },
 475        { "where", TRAILER_WHERE },
 476        { "ifexists", TRAILER_IF_EXISTS },
 477        { "ifmissing", TRAILER_IF_MISSING }
 478};
 479
 480static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 481{
 482        const char *trailer_item, *variable_name;
 483
 484        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 485                return 0;
 486
 487        variable_name = strrchr(trailer_item, '.');
 488        if (!variable_name) {
 489                if (!strcmp(trailer_item, "where")) {
 490                        if (set_where(&default_conf_info, value) < 0)
 491                                warning(_("unknown value '%s' for key '%s'"),
 492                                        value, conf_key);
 493                } else if (!strcmp(trailer_item, "ifexists")) {
 494                        if (set_if_exists(&default_conf_info, value) < 0)
 495                                warning(_("unknown value '%s' for key '%s'"),
 496                                        value, conf_key);
 497                } else if (!strcmp(trailer_item, "ifmissing")) {
 498                        if (set_if_missing(&default_conf_info, value) < 0)
 499                                warning(_("unknown value '%s' for key '%s'"),
 500                                        value, conf_key);
 501                } else if (!strcmp(trailer_item, "separators")) {
 502                        separators = xstrdup(value);
 503                }
 504        }
 505        return 0;
 506}
 507
 508static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 509{
 510        const char *trailer_item, *variable_name;
 511        struct trailer_item *item;
 512        struct conf_info *conf;
 513        char *name = NULL;
 514        enum trailer_info_type type;
 515        int i;
 516
 517        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 518                return 0;
 519
 520        variable_name = strrchr(trailer_item, '.');
 521        if (!variable_name)
 522                return 0;
 523
 524        variable_name++;
 525        for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 526                if (strcmp(trailer_config_items[i].name, variable_name))
 527                        continue;
 528                name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 529                type = trailer_config_items[i].type;
 530                break;
 531        }
 532
 533        if (!name)
 534                return 0;
 535
 536        item = get_conf_item(name);
 537        conf = &item->conf;
 538        free(name);
 539
 540        switch (type) {
 541        case TRAILER_KEY:
 542                if (conf->key)
 543                        warning(_("more than one %s"), conf_key);
 544                conf->key = xstrdup(value);
 545                break;
 546        case TRAILER_COMMAND:
 547                if (conf->command)
 548                        warning(_("more than one %s"), conf_key);
 549                conf->command = xstrdup(value);
 550                break;
 551        case TRAILER_WHERE:
 552                if (set_where(conf, value))
 553                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 554                break;
 555        case TRAILER_IF_EXISTS:
 556                if (set_if_exists(conf, value))
 557                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 558                break;
 559        case TRAILER_IF_MISSING:
 560                if (set_if_missing(conf, value))
 561                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 562                break;
 563        default:
 564                die("internal bug in trailer.c");
 565        }
 566        return 0;
 567}
 568
 569static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
 570{
 571        size_t len;
 572        struct strbuf seps = STRBUF_INIT;
 573        strbuf_addstr(&seps, separators);
 574        strbuf_addch(&seps, '=');
 575        len = strcspn(trailer, seps.buf);
 576        strbuf_release(&seps);
 577        if (len == 0) {
 578                int l = strlen(trailer);
 579                while (l > 0 && isspace(trailer[l - 1]))
 580                        l--;
 581                return error(_("empty trailer token in trailer '%.*s'"), l, trailer);
 582        }
 583        if (len < strlen(trailer)) {
 584                strbuf_add(tok, trailer, len);
 585                strbuf_trim(tok);
 586                strbuf_addstr(val, trailer + len + 1);
 587                strbuf_trim(val);
 588        } else {
 589                strbuf_addstr(tok, trailer);
 590                strbuf_trim(tok);
 591        }
 592        return 0;
 593}
 594
 595static const char *token_from_item(struct trailer_item *item, char *tok)
 596{
 597        if (item->conf.key)
 598                return item->conf.key;
 599        if (tok)
 600                return tok;
 601        return item->conf.name;
 602}
 603
 604static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
 605                                             char *tok, char *val)
 606{
 607        struct trailer_item *new = xcalloc(sizeof(*new), 1);
 608        new->value = val ? val : xstrdup("");
 609
 610        if (conf_item) {
 611                duplicate_conf(&new->conf, &conf_item->conf);
 612                new->token = xstrdup(token_from_item(conf_item, tok));
 613                free(tok);
 614        } else {
 615                duplicate_conf(&new->conf, &default_conf_info);
 616                new->token = tok;
 617        }
 618
 619        return new;
 620}
 621
 622static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
 623{
 624        if (!strncasecmp(tok, item->conf.name, tok_len))
 625                return 1;
 626        return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 627}
 628
 629static struct trailer_item *create_trailer_item(const char *string)
 630{
 631        struct strbuf tok = STRBUF_INIT;
 632        struct strbuf val = STRBUF_INIT;
 633        struct trailer_item *item;
 634        int tok_len;
 635
 636        if (parse_trailer(&tok, &val, string))
 637                return NULL;
 638
 639        tok_len = token_len_without_separator(tok.buf, tok.len);
 640
 641        /* Lookup if the token matches something in the config */
 642        for (item = first_conf_item; item; item = item->next) {
 643                if (token_matches_item(tok.buf, item, tok_len))
 644                        return new_trailer_item(item,
 645                                                strbuf_detach(&tok, NULL),
 646                                                strbuf_detach(&val, NULL));
 647        }
 648
 649        return new_trailer_item(NULL,
 650                                strbuf_detach(&tok, NULL),
 651                                strbuf_detach(&val, NULL));
 652}
 653
 654static void add_trailer_item(struct trailer_item **first,
 655                             struct trailer_item **last,
 656                             struct trailer_item *new)
 657{
 658        if (!new)
 659                return;
 660        if (!*last) {
 661                *first = new;
 662                *last = new;
 663        } else {
 664                (*last)->next = new;
 665                new->previous = *last;
 666                *last = new;
 667        }
 668}
 669
 670static struct trailer_item *process_command_line_args(struct string_list *trailers)
 671{
 672        struct trailer_item *arg_tok_first = NULL;
 673        struct trailer_item *arg_tok_last = NULL;
 674        struct string_list_item *tr;
 675        struct trailer_item *item;
 676
 677        /* Add a trailer item for each configured trailer with a command */
 678        for (item = first_conf_item; item; item = item->next) {
 679                if (item->conf.command) {
 680                        struct trailer_item *new = new_trailer_item(item, NULL, NULL);
 681                        add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 682                }
 683        }
 684
 685        /* Add a trailer item for each trailer on the command line */
 686        for_each_string_list_item(tr, trailers) {
 687                struct trailer_item *new = create_trailer_item(tr->string);
 688                add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 689        }
 690
 691        return arg_tok_first;
 692}
 693
 694static struct strbuf **read_input_file(const char *file)
 695{
 696        struct strbuf **lines;
 697        struct strbuf sb = STRBUF_INIT;
 698
 699        if (file) {
 700                if (strbuf_read_file(&sb, file, 0) < 0)
 701                        die_errno(_("could not read input file '%s'"), file);
 702        } else {
 703                if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 704                        die_errno(_("could not read from stdin"));
 705        }
 706
 707        lines = strbuf_split(&sb, '\n');
 708
 709        strbuf_release(&sb);
 710
 711        return lines;
 712}
 713
 714/*
 715 * Return the (0 based) index of the start of the patch or the line
 716 * count if there is no patch in the message.
 717 */
 718static int find_patch_start(struct strbuf **lines, int count)
 719{
 720        int i;
 721
 722        /* Get the start of the patch part if any */
 723        for (i = 0; i < count; i++) {
 724                if (starts_with(lines[i]->buf, "---"))
 725                        return i;
 726        }
 727
 728        return count;
 729}
 730
 731/*
 732 * Return the (0 based) index of the first trailer line or count if
 733 * there are no trailers. Trailers are searched only in the lines from
 734 * index (count - 1) down to index 0.
 735 */
 736static int find_trailer_start(struct strbuf **lines, int count)
 737{
 738        int start, only_spaces = 1;
 739
 740        /*
 741         * Get the start of the trailers by looking starting from the end
 742         * for a line with only spaces before lines with one separator.
 743         */
 744        for (start = count - 1; start >= 0; start--) {
 745                if (lines[start]->buf[0] == comment_line_char)
 746                        continue;
 747                if (contains_only_spaces(lines[start]->buf)) {
 748                        if (only_spaces)
 749                                continue;
 750                        return start + 1;
 751                }
 752                if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 753                        if (only_spaces)
 754                                only_spaces = 0;
 755                        continue;
 756                }
 757                return count;
 758        }
 759
 760        return only_spaces ? count : 0;
 761}
 762
 763/* Get the index of the end of the trailers */
 764static int find_trailer_end(struct strbuf **lines, int patch_start)
 765{
 766        struct strbuf sb = STRBUF_INIT;
 767        int i, ignore_bytes;
 768
 769        for (i = 0; i < patch_start; i++)
 770                strbuf_addbuf(&sb, lines[i]);
 771        ignore_bytes = ignore_non_trailer(&sb);
 772        strbuf_release(&sb);
 773        for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 774                ignore_bytes -= lines[i]->len;
 775
 776        return i + 1;
 777}
 778
 779static int has_blank_line_before(struct strbuf **lines, int start)
 780{
 781        for (;start >= 0; start--) {
 782                if (lines[start]->buf[0] == comment_line_char)
 783                        continue;
 784                return contains_only_spaces(lines[start]->buf);
 785        }
 786        return 0;
 787}
 788
 789static void print_lines(struct strbuf **lines, int start, int end)
 790{
 791        int i;
 792        for (i = start; lines[i] && i < end; i++)
 793                printf("%s", lines[i]->buf);
 794}
 795
 796static int process_input_file(struct strbuf **lines,
 797                              struct trailer_item **in_tok_first,
 798                              struct trailer_item **in_tok_last)
 799{
 800        int count = 0;
 801        int patch_start, trailer_start, trailer_end, i;
 802
 803        /* Get the line count */
 804        while (lines[count])
 805                count++;
 806
 807        patch_start = find_patch_start(lines, count);
 808        trailer_end = find_trailer_end(lines, patch_start);
 809        trailer_start = find_trailer_start(lines, trailer_end);
 810
 811        /* Print lines before the trailers as is */
 812        print_lines(lines, 0, trailer_start);
 813
 814        if (!has_blank_line_before(lines, trailer_start - 1))
 815                printf("\n");
 816
 817        /* Parse trailer lines */
 818        for (i = trailer_start; i < trailer_end; i++) {
 819                if (lines[i]->buf[0] != comment_line_char) {
 820                        struct trailer_item *new = create_trailer_item(lines[i]->buf);
 821                        add_trailer_item(in_tok_first, in_tok_last, new);
 822                }
 823        }
 824
 825        return trailer_end;
 826}
 827
 828static void free_all(struct trailer_item **first)
 829{
 830        while (*first) {
 831                struct trailer_item *item = remove_first(first);
 832                free_trailer_item(item);
 833        }
 834}
 835
 836void process_trailers(const char *file, int trim_empty, struct string_list *trailers)
 837{
 838        struct trailer_item *in_tok_first = NULL;
 839        struct trailer_item *in_tok_last = NULL;
 840        struct trailer_item *arg_tok_first;
 841        struct strbuf **lines;
 842        int trailer_end;
 843
 844        /* Default config must be setup first */
 845        git_config(git_trailer_default_config, NULL);
 846        git_config(git_trailer_config, NULL);
 847
 848        lines = read_input_file(file);
 849
 850        /* Print the lines before the trailers */
 851        trailer_end = process_input_file(lines, &in_tok_first, &in_tok_last);
 852
 853        arg_tok_first = process_command_line_args(trailers);
 854
 855        process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 856
 857        print_all(in_tok_first, trim_empty);
 858
 859        free_all(&in_tok_first);
 860
 861        /* Print the lines after the trailers as is */
 862        print_lines(lines, trailer_end, INT_MAX);
 863
 864        strbuf_list_free(lines);
 865}