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