git.oblomov.eu Git - git/blob - trailer.c

   1 #include "cache.h"
   2 #include "string-list.h"
   3 #include "run-command.h"
   4 #include "string-list.h"
   5 #include "commit.h"
   6 #include "trailer.h"
   7 /*
   8  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
   9  */
  10
  11 enum action_where { WHERE_END, WHERE_AFTER, WHERE_BEFORE, WHERE_START };
  12 enum action_if_exists { EXISTS_ADD_IF_DIFFERENT_NEIGHBOR, EXISTS_ADD_IF_DIFFERENT,
  13                         EXISTS_ADD, EXISTS_REPLACE, EXISTS_DO_NOTHING };
  14 enum action_if_missing { MISSING_ADD, MISSING_DO_NOTHING };
  15
  16 struct conf_info {
  17         char *name;
  18         char *key;
  19         char *command;
  20         enum action_where where;
  21         enum action_if_exists if_exists;
  22         enum action_if_missing if_missing;
  23 };
  24
  25 static struct conf_info default_conf_info;
  26
  27 struct trailer_item {
  28         struct trailer_item *previous;
  29         struct trailer_item *next;
  30         const char *token;
  31         const char *value;
  32         struct conf_info conf;
  33 };
  34
  35 static struct trailer_item *first_conf_item;
  36
  37 static char *separators = ":";
  38
  39 #define TRAILER_ARG_STRING "$ARG"
  40
  41 static int after_or_end(enum action_where where)
  42 {
  43         return (where == WHERE_AFTER) || (where == WHERE_END);
  44 }
  45
  46 /*
  47  * Return the length of the string not including any final
  48  * punctuation. E.g., the input "Signed-off-by:" would return
  49  * 13, stripping the trailing punctuation but retaining
  50  * internal punctuation.
  51  */
  52 static size_t token_len_without_separator(const char *token, size_t len)
  53 {
  54         while (len > 0 && !isalnum(token[len - 1]))
  55                 len--;
  56         return len;
  57 }
  58
  59 static int same_token(struct trailer_item *a, struct trailer_item *b)
  60 {
  61         size_t a_len = token_len_without_separator(a->token, strlen(a->token));
  62         size_t b_len = token_len_without_separator(b->token, strlen(b->token));
  63         size_t min_len = (a_len > b_len) ? b_len : a_len;
  64
  65         return !strncasecmp(a->token, b->token, min_len);
  66 }
  67
  68 static int same_value(struct trailer_item *a, struct trailer_item *b)
  69 {
  70         return !strcasecmp(a->value, b->value);
  71 }
  72
  73 static int same_trailer(struct trailer_item *a, struct trailer_item *b)
  74 {
  75         return same_token(a, b) && same_value(a, b);
  76 }
  77
  78 static inline int contains_only_spaces(const char *str)
  79 {
  80         const char *s = str;
  81         while (*s && isspace(*s))
  82                 s++;
  83         return !*s;
  84 }
  85
  86 static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
  87 {
  88         const char *ptr = strstr(sb->buf, a);
  89         if (ptr)
  90                 strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
  91 }
  92
  93 static void free_trailer_item(struct trailer_item *item)
  94 {
  95         free(item->conf.name);
  96         free(item->conf.key);
  97         free(item->conf.command);
  98         free((char *)item->token);
  99         free((char *)item->value);
 100         free(item);
 101 }
 102
 103 static char last_non_space_char(const char *s)
 104 {
 105         int i;
 106         for (i = strlen(s) - 1; i >= 0; i--)
 107                 if (!isspace(s[i]))
 108                         return s[i];
 109         return '\0';
 110 }
 111
 112 static void print_tok_val(const char *tok, const char *val)
 113 {
 114         char c = last_non_space_char(tok);
 115         if (!c)
 116                 return;
 117         if (strchr(separators, c))
 118                 printf("%s%s\n", tok, val);
 119         else
 120                 printf("%s%c %s\n", tok, separators[0], val);
 121 }
 122
 123 static void print_all(struct trailer_item *first, int trim_empty)
 124 {
 125         struct trailer_item *item;
 126         for (item = first; item; item = item->next) {
 127                 if (!trim_empty || strlen(item->value) > 0)
 128                         print_tok_val(item->token, item->value);
 129         }
 130 }
 131
 132 static void update_last(struct trailer_item **last)
 133 {
 134         if (*last)
 135                 while ((*last)->next != NULL)
 136                         *last = (*last)->next;
 137 }
 138
 139 static void update_first(struct trailer_item **first)
 140 {
 141         if (*first)
 142                 while ((*first)->previous != NULL)
 143                         *first = (*first)->previous;
 144 }
 145
 146 static void add_arg_to_input_list(struct trailer_item *on_tok,
 147                                   struct trailer_item *arg_tok,
 148                                   struct trailer_item **first,
 149                                   struct trailer_item **last)
 150 {
 151         if (after_or_end(arg_tok->conf.where)) {
 152                 arg_tok->next = on_tok->next;
 153                 on_tok->next = arg_tok;
 154                 arg_tok->previous = on_tok;
 155                 if (arg_tok->next)
 156                         arg_tok->next->previous = arg_tok;
 157                 update_last(last);
 158         } else {
 159                 arg_tok->previous = on_tok->previous;
 160                 on_tok->previous = arg_tok;
 161                 arg_tok->next = on_tok;
 162                 if (arg_tok->previous)
 163                         arg_tok->previous->next = arg_tok;
 164                 update_first(first);
 165         }
 166 }
 167
 168 static int check_if_different(struct trailer_item *in_tok,
 169                               struct trailer_item *arg_tok,
 170                               int check_all)
 171 {
 172         enum action_where where = arg_tok->conf.where;
 173         do {
 174                 if (!in_tok)
 175                         return 1;
 176                 if (same_trailer(in_tok, arg_tok))
 177                         return 0;
 178                 /*
 179                  * if we want to add a trailer after another one,
 180                  * we have to check those before this one
 181                  */
 182                 in_tok = after_or_end(where) ? in_tok->previous : in_tok->next;
 183         } while (check_all);
 184         return 1;
 185 }
 186
 187 static void remove_from_list(struct trailer_item *item,
 188                              struct trailer_item **first,
 189                              struct trailer_item **last)
 190 {
 191         struct trailer_item *next = item->next;
 192         struct trailer_item *previous = item->previous;
 193
 194         if (next) {
 195                 item->next->previous = previous;
 196                 item->next = NULL;
 197         } else if (last)
 198                 *last = previous;
 199
 200         if (previous) {
 201                 item->previous->next = next;
 202                 item->previous = NULL;
 203         } else if (first)
 204                 *first = next;
 205 }
 206
 207 static struct trailer_item *remove_first(struct trailer_item **first)
 208 {
 209         struct trailer_item *item = *first;
 210         *first = item->next;
 211         if (item->next) {
 212                 item->next->previous = NULL;
 213                 item->next = NULL;
 214         }
 215         return item;
 216 }
 217
 218 static int read_from_command(struct child_process *cp, struct strbuf *buf)
 219 {
 220         if (run_command(cp))
 221                 return error("running trailer command '%s' failed", cp->argv[0]);
 222         if (strbuf_read(buf, cp->out, 1024) < 1)
 223                 return error("reading from trailer command '%s' failed", cp->argv[0]);
 224         strbuf_trim(buf);
 225         return 0;
 226 }
 227
 228 static const char *apply_command(const char *command, const char *arg)
 229 {
 230         struct strbuf cmd = STRBUF_INIT;
 231         struct strbuf buf = STRBUF_INIT;
 232         struct child_process cp = CHILD_PROCESS_INIT;
 233         const char *argv[] = {NULL, NULL};
 234         const char *result;
 235
 236         strbuf_addstr(&cmd, command);
 237         if (arg)
 238                 strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 239
 240         argv[0] = cmd.buf;
 241         cp.argv = argv;
 242         cp.env = local_repo_env;
 243         cp.no_stdin = 1;
 244         cp.out = -1;
 245         cp.use_shell = 1;
 246
 247         if (read_from_command(&cp, &buf)) {
 248                 strbuf_release(&buf);
 249                 result = xstrdup("");
 250         } else
 251                 result = strbuf_detach(&buf, NULL);
 252
 253         strbuf_release(&cmd);
 254         return result;
 255 }
 256
 257 static void apply_item_command(struct trailer_item *in_tok, struct trailer_item *arg_tok)
 258 {
 259         if (arg_tok->conf.command) {
 260                 const char *arg;
 261                 if (arg_tok->value && arg_tok->value[0]) {
 262                         arg = arg_tok->value;
 263                 } else {
 264                         if (in_tok && in_tok->value)
 265                                 arg = xstrdup(in_tok->value);
 266                         else
 267                                 arg = xstrdup("");
 268                 }
 269                 arg_tok->value = apply_command(arg_tok->conf.command, arg);
 270                 free((char *)arg);
 271         }
 272 }
 273
 274 static void apply_arg_if_exists(struct trailer_item *in_tok,
 275                                 struct trailer_item *arg_tok,
 276                                 struct trailer_item *on_tok,
 277                                 struct trailer_item **in_tok_first,
 278                                 struct trailer_item **in_tok_last)
 279 {
 280         switch (arg_tok->conf.if_exists) {
 281         case EXISTS_DO_NOTHING:
 282                 free_trailer_item(arg_tok);
 283                 break;
 284         case EXISTS_REPLACE:
 285                 apply_item_command(in_tok, arg_tok);
 286                 add_arg_to_input_list(on_tok, arg_tok,
 287                                       in_tok_first, in_tok_last);
 288                 remove_from_list(in_tok, in_tok_first, in_tok_last);
 289                 free_trailer_item(in_tok);
 290                 break;
 291         case EXISTS_ADD:
 292                 apply_item_command(in_tok, arg_tok);
 293                 add_arg_to_input_list(on_tok, arg_tok,
 294                                       in_tok_first, in_tok_last);
 295                 break;
 296         case EXISTS_ADD_IF_DIFFERENT:
 297                 apply_item_command(in_tok, arg_tok);
 298                 if (check_if_different(in_tok, arg_tok, 1))
 299                         add_arg_to_input_list(on_tok, arg_tok,
 300                                               in_tok_first, in_tok_last);
 301                 else
 302                         free_trailer_item(arg_tok);
 303                 break;
 304         case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 305                 apply_item_command(in_tok, arg_tok);
 306                 if (check_if_different(on_tok, arg_tok, 0))
 307                         add_arg_to_input_list(on_tok, arg_tok,
 308                                               in_tok_first, in_tok_last);
 309                 else
 310                         free_trailer_item(arg_tok);
 311                 break;
 312         }
 313 }
 314
 315 static void apply_arg_if_missing(struct trailer_item **in_tok_first,
 316                                  struct trailer_item **in_tok_last,
 317                                  struct trailer_item *arg_tok)
 318 {
 319         struct trailer_item **in_tok;
 320         enum action_where where;
 321
 322         switch (arg_tok->conf.if_missing) {
 323         case MISSING_DO_NOTHING:
 324                 free_trailer_item(arg_tok);
 325                 break;
 326         case MISSING_ADD:
 327                 where = arg_tok->conf.where;
 328                 in_tok = after_or_end(where) ? in_tok_last : in_tok_first;
 329                 apply_item_command(NULL, arg_tok);
 330                 if (*in_tok) {
 331                         add_arg_to_input_list(*in_tok, arg_tok,
 332                                               in_tok_first, in_tok_last);
 333                 } else {
 334                         *in_tok_first = arg_tok;
 335                         *in_tok_last = arg_tok;
 336                 }
 337                 break;
 338         }
 339 }
 340
 341 static int find_same_and_apply_arg(struct trailer_item **in_tok_first,
 342                                    struct trailer_item **in_tok_last,
 343                                    struct trailer_item *arg_tok)
 344 {
 345         struct trailer_item *in_tok;
 346         struct trailer_item *on_tok;
 347         struct trailer_item *following_tok;
 348
 349         enum action_where where = arg_tok->conf.where;
 350         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 351         int backwards = after_or_end(where);
 352         struct trailer_item *start_tok = backwards ? *in_tok_last : *in_tok_first;
 353
 354         for (in_tok = start_tok; in_tok; in_tok = following_tok) {
 355                 following_tok = backwards ? in_tok->previous : in_tok->next;
 356                 if (!same_token(in_tok, arg_tok))
 357                         continue;
 358                 on_tok = middle ? in_tok : start_tok;
 359                 apply_arg_if_exists(in_tok, arg_tok, on_tok,
 360                                     in_tok_first, in_tok_last);
 361                 return 1;
 362         }
 363         return 0;
 364 }
 365
 366 static void process_trailers_lists(struct trailer_item **in_tok_first,
 367                                    struct trailer_item **in_tok_last,
 368                                    struct trailer_item **arg_tok_first)
 369 {
 370         struct trailer_item *arg_tok;
 371         struct trailer_item *next_arg;
 372
 373         if (!*arg_tok_first)
 374                 return;
 375
 376         for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
 377                 int applied = 0;
 378
 379                 next_arg = arg_tok->next;
 380                 remove_from_list(arg_tok, arg_tok_first, NULL);
 381
 382                 applied = find_same_and_apply_arg(in_tok_first,
 383                                                   in_tok_last,
 384                                                   arg_tok);
 385
 386                 if (!applied)
 387                         apply_arg_if_missing(in_tok_first,
 388                                              in_tok_last,
 389                                              arg_tok);
 390         }
 391 }
 392
 393 static int set_where(struct conf_info *item, const char *value)
 394 {
 395         if (!strcasecmp("after", value))
 396                 item->where = WHERE_AFTER;
 397         else if (!strcasecmp("before", value))
 398                 item->where = WHERE_BEFORE;
 399         else if (!strcasecmp("end", value))
 400                 item->where = WHERE_END;
 401         else if (!strcasecmp("start", value))
 402                 item->where = WHERE_START;
 403         else
 404                 return -1;
 405         return 0;
 406 }
 407
 408 static int set_if_exists(struct conf_info *item, const char *value)
 409 {
 410         if (!strcasecmp("addIfDifferent", value))
 411                 item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 412         else if (!strcasecmp("addIfDifferentNeighbor", value))
 413                 item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 414         else if (!strcasecmp("add", value))
 415                 item->if_exists = EXISTS_ADD;
 416         else if (!strcasecmp("replace", value))
 417                 item->if_exists = EXISTS_REPLACE;
 418         else if (!strcasecmp("doNothing", value))
 419                 item->if_exists = EXISTS_DO_NOTHING;
 420         else
 421                 return -1;
 422         return 0;
 423 }
 424
 425 static int set_if_missing(struct conf_info *item, const char *value)
 426 {
 427         if (!strcasecmp("doNothing", value))
 428                 item->if_missing = MISSING_DO_NOTHING;
 429         else if (!strcasecmp("add", value))
 430                 item->if_missing = MISSING_ADD;
 431         else
 432                 return -1;
 433         return 0;
 434 }
 435
 436 static void duplicate_conf(struct conf_info *dst, struct conf_info *src)
 437 {
 438         *dst = *src;
 439         if (src->name)
 440                 dst->name = xstrdup(src->name);
 441         if (src->key)
 442                 dst->key = xstrdup(src->key);
 443         if (src->command)
 444                 dst->command = xstrdup(src->command);
 445 }
 446
 447 static struct trailer_item *get_conf_item(const char *name)
 448 {
 449         struct trailer_item *item;
 450         struct trailer_item *previous;
 451
 452         /* Look up item with same name */
 453         for (previous = NULL, item = first_conf_item;
 454              item;
 455              previous = item, item = item->next) {
 456                 if (!strcasecmp(item->conf.name, name))
 457                         return item;
 458         }
 459
 460         /* Item does not already exists, create it */
 461         item = xcalloc(sizeof(struct trailer_item), 1);
 462         duplicate_conf(&item->conf, &default_conf_info);
 463         item->conf.name = xstrdup(name);
 464
 465         if (!previous)
 466                 first_conf_item = item;
 467         else {
 468                 previous->next = item;
 469                 item->previous = previous;
 470         }
 471
 472         return item;
 473 }
 474
 475 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 476                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 477
 478 static struct {
 479         const char *name;
 480         enum trailer_info_type type;
 481 } trailer_config_items[] = {
 482         { "key", TRAILER_KEY },
 483         { "command", TRAILER_COMMAND },
 484         { "where", TRAILER_WHERE },
 485         { "ifexists", TRAILER_IF_EXISTS },
 486         { "ifmissing", TRAILER_IF_MISSING }
 487 };
 488
 489 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 490 {
 491         const char *trailer_item, *variable_name;
 492
 493         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 494                 return 0;
 495
 496         variable_name = strrchr(trailer_item, '.');
 497         if (!variable_name) {
 498                 if (!strcmp(trailer_item, "where")) {
 499                         if (set_where(&default_conf_info, value) < 0)
 500                                 warning(_("unknown value '%s' for key '%s'"),
 501                                         value, conf_key);
 502                 } else if (!strcmp(trailer_item, "ifexists")) {
 503                         if (set_if_exists(&default_conf_info, value) < 0)
 504                                 warning(_("unknown value '%s' for key '%s'"),
 505                                         value, conf_key);
 506                 } else if (!strcmp(trailer_item, "ifmissing")) {
 507                         if (set_if_missing(&default_conf_info, value) < 0)
 508                                 warning(_("unknown value '%s' for key '%s'"),
 509                                         value, conf_key);
 510                 } else if (!strcmp(trailer_item, "separators")) {
 511                         separators = xstrdup(value);
 512                 }
 513         }
 514         return 0;
 515 }
 516
 517 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 518 {
 519         const char *trailer_item, *variable_name;
 520         struct trailer_item *item;
 521         struct conf_info *conf;
 522         char *name = NULL;
 523         enum trailer_info_type type;
 524         int i;
 525
 526         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 527                 return 0;
 528
 529         variable_name = strrchr(trailer_item, '.');
 530         if (!variable_name)
 531                 return 0;
 532
 533         variable_name++;
 534         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 535                 if (strcmp(trailer_config_items[i].name, variable_name))
 536                         continue;
 537                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 538                 type = trailer_config_items[i].type;
 539                 break;
 540         }
 541
 542         if (!name)
 543                 return 0;
 544
 545         item = get_conf_item(name);
 546         conf = &item->conf;
 547         free(name);
 548
 549         switch (type) {
 550         case TRAILER_KEY:
 551                 if (conf->key)
 552                         warning(_("more than one %s"), conf_key);
 553                 conf->key = xstrdup(value);
 554                 break;
 555         case TRAILER_COMMAND:
 556                 if (conf->command)
 557                         warning(_("more than one %s"), conf_key);
 558                 conf->command = xstrdup(value);
 559                 break;
 560         case TRAILER_WHERE:
 561                 if (set_where(conf, value))
 562                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 563                 break;
 564         case TRAILER_IF_EXISTS:
 565                 if (set_if_exists(conf, value))
 566                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 567                 break;
 568         case TRAILER_IF_MISSING:
 569                 if (set_if_missing(conf, value))
 570                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 571                 break;
 572         default:
 573                 die("internal bug in trailer.c");
 574         }
 575         return 0;
 576 }
 577
 578 static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
 579 {
 580         size_t len;
 581         struct strbuf seps = STRBUF_INIT;
 582         strbuf_addstr(&seps, separators);
 583         strbuf_addch(&seps, '=');
 584         len = strcspn(trailer, seps.buf);
 585         strbuf_release(&seps);
 586         if (len == 0) {
 587                 int l = strlen(trailer);
 588                 while (l > 0 && isspace(trailer[l - 1]))
 589                         l--;
 590                 return error(_("empty trailer token in trailer '%.*s'"), l, trailer);
 591         }
 592         if (len < strlen(trailer)) {
 593                 strbuf_add(tok, trailer, len);
 594                 strbuf_trim(tok);
 595                 strbuf_addstr(val, trailer + len + 1);
 596                 strbuf_trim(val);
 597         } else {
 598                 strbuf_addstr(tok, trailer);
 599                 strbuf_trim(tok);
 600         }
 601         return 0;
 602 }
 603
 604 static const char *token_from_item(struct trailer_item *item, char *tok)
 605 {
 606         if (item->conf.key)
 607                 return item->conf.key;
 608         if (tok)
 609                 return tok;
 610         return item->conf.name;
 611 }
 612
 613 static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
 614                                              char *tok, char *val)
 615 {
 616         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 617         new->value = val ? val : xstrdup("");
 618
 619         if (conf_item) {
 620                 duplicate_conf(&new->conf, &conf_item->conf);
 621                 new->token = xstrdup(token_from_item(conf_item, tok));
 622                 free(tok);
 623         } else {
 624                 duplicate_conf(&new->conf, &default_conf_info);
 625                 new->token = tok;
 626         }
 627
 628         return new;
 629 }
 630
 631 static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
 632 {
 633         if (!strncasecmp(tok, item->conf.name, tok_len))
 634                 return 1;
 635         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 636 }
 637
 638 static struct trailer_item *create_trailer_item(const char *string)
 639 {
 640         struct strbuf tok = STRBUF_INIT;
 641         struct strbuf val = STRBUF_INIT;
 642         struct trailer_item *item;
 643         int tok_len;
 644
 645         if (parse_trailer(&tok, &val, string))
 646                 return NULL;
 647
 648         tok_len = token_len_without_separator(tok.buf, tok.len);
 649
 650         /* Lookup if the token matches something in the config */
 651         for (item = first_conf_item; item; item = item->next) {
 652                 if (token_matches_item(tok.buf, item, tok_len))
 653                         return new_trailer_item(item,
 654                                                 strbuf_detach(&tok, NULL),
 655                                                 strbuf_detach(&val, NULL));
 656         }
 657
 658         return new_trailer_item(NULL,
 659                                 strbuf_detach(&tok, NULL),
 660                                 strbuf_detach(&val, NULL));
 661 }
 662
 663 static void add_trailer_item(struct trailer_item **first,
 664                              struct trailer_item **last,
 665                              struct trailer_item *new)
 666 {
 667         if (!new)
 668                 return;
 669         if (!*last) {
 670                 *first = new;
 671                 *last = new;
 672         } else {
 673                 (*last)->next = new;
 674                 new->previous = *last;
 675                 *last = new;
 676         }
 677 }
 678
 679 static struct trailer_item *process_command_line_args(struct string_list *trailers)
 680 {
 681         struct trailer_item *arg_tok_first = NULL;
 682         struct trailer_item *arg_tok_last = NULL;
 683         struct string_list_item *tr;
 684         struct trailer_item *item;
 685
 686         /* Add a trailer item for each configured trailer with a command */
 687         for (item = first_conf_item; item; item = item->next) {
 688                 if (item->conf.command) {
 689                         struct trailer_item *new = new_trailer_item(item, NULL, NULL);
 690                         add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 691                 }
 692         }
 693
 694         /* Add a trailer item for each trailer on the command line */
 695         for_each_string_list_item(tr, trailers) {
 696                 struct trailer_item *new = create_trailer_item(tr->string);
 697                 add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 698         }
 699
 700         return arg_tok_first;
 701 }
 702
 703 static struct strbuf **read_input_file(const char *file)
 704 {
 705         struct strbuf **lines;
 706         struct strbuf sb = STRBUF_INIT;
 707
 708         if (file) {
 709                 if (strbuf_read_file(&sb, file, 0) < 0)
 710                         die_errno(_("could not read input file '%s'"), file);
 711         } else {
 712                 if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 713                         die_errno(_("could not read from stdin"));
 714         }
 715
 716         lines = strbuf_split(&sb, '\n');
 717
 718         strbuf_release(&sb);
 719
 720         return lines;
 721 }
 722
 723 /*
 724  * Return the (0 based) index of the start of the patch or the line
 725  * count if there is no patch in the message.
 726  */
 727 static int find_patch_start(struct strbuf **lines, int count)
 728 {
 729         int i;
 730
 731         /* Get the start of the patch part if any */
 732         for (i = 0; i < count; i++) {
 733                 if (starts_with(lines[i]->buf, "---"))
 734                         return i;
 735         }
 736
 737         return count;
 738 }
 739
 740 /*
 741  * Return the (0 based) index of the first trailer line or count if
 742  * there are no trailers. Trailers are searched only in the lines from
 743  * index (count - 1) down to index 0.
 744  */
 745 static int find_trailer_start(struct strbuf **lines, int count)
 746 {
 747         int start, only_spaces = 1;
 748
 749         /*
 750          * Get the start of the trailers by looking starting from the end
 751          * for a line with only spaces before lines with one separator.
 752          */
 753         for (start = count - 1; start >= 0; start--) {
 754                 if (lines[start]->buf[0] == comment_line_char)
 755                         continue;
 756                 if (contains_only_spaces(lines[start]->buf)) {
 757                         if (only_spaces)
 758                                 continue;
 759                         return start + 1;
 760                 }
 761                 if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 762                         if (only_spaces)
 763                                 only_spaces = 0;
 764                         continue;
 765                 }
 766                 return count;
 767         }
 768
 769         return only_spaces ? count : 0;
 770 }
 771
 772 /* Get the index of the end of the trailers */
 773 static int find_trailer_end(struct strbuf **lines, int patch_start)
 774 {
 775         struct strbuf sb = STRBUF_INIT;
 776         int i, ignore_bytes;
 777
 778         for (i = 0; i < patch_start; i++)
 779                 strbuf_addbuf(&sb, lines[i]);
 780         ignore_bytes = ignore_non_trailer(&sb);
 781         strbuf_release(&sb);
 782         for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 783                 ignore_bytes -= lines[i]->len;
 784
 785         return i + 1;
 786 }
 787
 788 static int has_blank_line_before(struct strbuf **lines, int start)
 789 {
 790         for (;start >= 0; start--) {
 791                 if (lines[start]->buf[0] == comment_line_char)
 792                         continue;
 793                 return contains_only_spaces(lines[start]->buf);
 794         }
 795         return 0;
 796 }
 797
 798 static void print_lines(struct strbuf **lines, int start, int end)
 799 {
 800         int i;
 801         for (i = start; lines[i] && i < end; i++)
 802                 printf("%s", lines[i]->buf);
 803 }
 804
 805 static int process_input_file(struct strbuf **lines,
 806                               struct trailer_item **in_tok_first,
 807                               struct trailer_item **in_tok_last)
 808 {
 809         int count = 0;
 810         int patch_start, trailer_start, trailer_end, i;
 811
 812         /* Get the line count */
 813         while (lines[count])
 814                 count++;
 815
 816         patch_start = find_patch_start(lines, count);
 817         trailer_end = find_trailer_end(lines, patch_start);
 818         trailer_start = find_trailer_start(lines, trailer_end);
 819
 820         /* Print lines before the trailers as is */
 821         print_lines(lines, 0, trailer_start);
 822
 823         if (!has_blank_line_before(lines, trailer_start - 1))
 824                 printf("\n");
 825
 826         /* Parse trailer lines */
 827         for (i = trailer_start; i < trailer_end; i++) {
 828                 if (lines[i]->buf[0] != comment_line_char) {
 829                         struct trailer_item *new = create_trailer_item(lines[i]->buf);
 830                         add_trailer_item(in_tok_first, in_tok_last, new);
 831                 }
 832         }
 833
 834         return trailer_end;
 835 }
 836
 837 static void free_all(struct trailer_item **first)
 838 {
 839         while (*first) {
 840                 struct trailer_item *item = remove_first(first);
 841                 free_trailer_item(item);
 842         }
 843 }
 844
 845 void process_trailers(const char *file, int trim_empty, struct string_list *trailers)
 846 {
 847         struct trailer_item *in_tok_first = NULL;
 848         struct trailer_item *in_tok_last = NULL;
 849         struct trailer_item *arg_tok_first;
 850         struct strbuf **lines;
 851         int trailer_end;
 852
 853         /* Default config must be setup first */
 854         git_config(git_trailer_default_config, NULL);
 855         git_config(git_trailer_config, NULL);
 856
 857         lines = read_input_file(file);
 858
 859         /* Print the lines before the trailers */
 860         trailer_end = process_input_file(lines, &in_tok_first, &in_tok_last);
 861
 862         arg_tok_first = process_command_line_args(trailers);
 863
 864         process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 865
 866         print_all(in_tok_first, trim_empty);
 867
 868         free_all(&in_tok_first);
 869
 870         /* Print the lines after the trailers as is */
 871         print_lines(lines, trailer_end, INT_MAX);
 872
 873         strbuf_list_free(lines);
 874 }