trailer.c

   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
  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 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
 248 static 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
 265 static 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
 306 static 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
 332 static 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
 357 static 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
 384 static 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
 399 static 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
 416 static 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
 427 static 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
 438 static 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
 466 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 467                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 468
 469 static 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
 480 static 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
 508 static 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
 569 static 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
 595 static 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
 604 static 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
 622 static 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
 629 static 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
 654 static 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
 670 static 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
 694 static 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  */
 718 static 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  */
 736 static 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          * The first line must not be analyzed as the others as it
 744          * should be either the message title or a blank line.
 745          */
 746         for (start = count - 1; start >= 1; start--) {
 747                 if (lines[start]->buf[0] == comment_line_char)
 748                         continue;
 749                 if (contains_only_spaces(lines[start]->buf)) {
 750                         if (only_spaces)
 751                                 continue;
 752                         return start + 1;
 753                 }
 754                 if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 755                         if (only_spaces)
 756                                 only_spaces = 0;
 757                         continue;
 758                 }
 759                 return count;
 760         }
 761
 762         return only_spaces ? count : 0;
 763 }
 764
 765 /* Get the index of the end of the trailers */
 766 static int find_trailer_end(struct strbuf **lines, int patch_start)
 767 {
 768         struct strbuf sb = STRBUF_INIT;
 769         int i, ignore_bytes;
 770
 771         for (i = 0; i < patch_start; i++)
 772                 strbuf_addbuf(&sb, lines[i]);
 773         ignore_bytes = ignore_non_trailer(&sb);
 774         strbuf_release(&sb);
 775         for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 776                 ignore_bytes -= lines[i]->len;
 777
 778         return i + 1;
 779 }
 780
 781 static int has_blank_line_before(struct strbuf **lines, int start)
 782 {
 783         for (;start >= 0; start--) {
 784                 if (lines[start]->buf[0] == comment_line_char)
 785                         continue;
 786                 return contains_only_spaces(lines[start]->buf);
 787         }
 788         return 0;
 789 }
 790
 791 static void print_lines(struct strbuf **lines, int start, int end)
 792 {
 793         int i;
 794         for (i = start; lines[i] && i < end; i++)
 795                 printf("%s", lines[i]->buf);
 796 }
 797
 798 static int process_input_file(struct strbuf **lines,
 799                               struct trailer_item **in_tok_first,
 800                               struct trailer_item **in_tok_last)
 801 {
 802         int count = 0;
 803         int patch_start, trailer_start, trailer_end, i;
 804
 805         /* Get the line count */
 806         while (lines[count])
 807                 count++;
 808
 809         patch_start = find_patch_start(lines, count);
 810         trailer_end = find_trailer_end(lines, patch_start);
 811         trailer_start = find_trailer_start(lines, trailer_end);
 812
 813         /* Print lines before the trailers as is */
 814         print_lines(lines, 0, trailer_start);
 815
 816         if (!has_blank_line_before(lines, trailer_start - 1))
 817                 printf("\n");
 818
 819         /* Parse trailer lines */
 820         for (i = trailer_start; i < trailer_end; i++) {
 821                 if (lines[i]->buf[0] != comment_line_char) {
 822                         struct trailer_item *new = create_trailer_item(lines[i]->buf);
 823                         add_trailer_item(in_tok_first, in_tok_last, new);
 824                 }
 825         }
 826
 827         return trailer_end;
 828 }
 829
 830 static void free_all(struct trailer_item **first)
 831 {
 832         while (*first) {
 833                 struct trailer_item *item = remove_first(first);
 834                 free_trailer_item(item);
 835         }
 836 }
 837
 838 void process_trailers(const char *file, int trim_empty, struct string_list *trailers)
 839 {
 840         struct trailer_item *in_tok_first = NULL;
 841         struct trailer_item *in_tok_last = NULL;
 842         struct trailer_item *arg_tok_first;
 843         struct strbuf **lines;
 844         int trailer_end;
 845
 846         /* Default config must be setup first */
 847         git_config(git_trailer_default_config, NULL);
 848         git_config(git_trailer_config, NULL);
 849
 850         lines = read_input_file(file);
 851
 852         /* Print the lines before the trailers */
 853         trailer_end = process_input_file(lines, &in_tok_first, &in_tok_last);
 854
 855         arg_tok_first = process_command_line_args(trailers);
 856
 857         process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 858
 859         print_all(in_tok_first, trim_empty);
 860
 861         free_all(&in_tok_first);
 862
 863         /* Print the lines after the trailers as is */
 864         print_lines(lines, trailer_end, INT_MAX);
 865
 866         strbuf_list_free(lines);
 867 }