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

   1 #include "cache.h"
   2 #include "string-list.h"
   3 #include "run-command.h"
   4 #include "commit.h"
   5 #include "tempfile.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(FILE *outfile, 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                 fprintf(outfile, "%s%s\n", tok, val);
 119         else
 120                 fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 121 }
 122
 123 static void print_all(FILE *outfile, 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(outfile, 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 const char *apply_command(const char *command, const char *arg)
 219 {
 220         struct strbuf cmd = STRBUF_INIT;
 221         struct strbuf buf = STRBUF_INIT;
 222         struct child_process cp = CHILD_PROCESS_INIT;
 223         const char *argv[] = {NULL, NULL};
 224         const char *result;
 225
 226         strbuf_addstr(&cmd, command);
 227         if (arg)
 228                 strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 229
 230         argv[0] = cmd.buf;
 231         cp.argv = argv;
 232         cp.env = local_repo_env;
 233         cp.no_stdin = 1;
 234         cp.use_shell = 1;
 235
 236         if (capture_command(&cp, &buf, 1024)) {
 237                 error(_("running trailer command '%s' failed"), cmd.buf);
 238                 strbuf_release(&buf);
 239                 result = xstrdup("");
 240         } else {
 241                 strbuf_trim(&buf);
 242                 result = strbuf_detach(&buf, NULL);
 243         }
 244
 245         strbuf_release(&cmd);
 246         return result;
 247 }
 248
 249 static void apply_item_command(struct trailer_item *in_tok, struct trailer_item *arg_tok)
 250 {
 251         if (arg_tok->conf.command) {
 252                 const char *arg;
 253                 if (arg_tok->value && arg_tok->value[0]) {
 254                         arg = arg_tok->value;
 255                 } else {
 256                         if (in_tok && in_tok->value)
 257                                 arg = xstrdup(in_tok->value);
 258                         else
 259                                 arg = xstrdup("");
 260                 }
 261                 arg_tok->value = apply_command(arg_tok->conf.command, arg);
 262                 free((char *)arg);
 263         }
 264 }
 265
 266 static void apply_arg_if_exists(struct trailer_item *in_tok,
 267                                 struct trailer_item *arg_tok,
 268                                 struct trailer_item *on_tok,
 269                                 struct trailer_item **in_tok_first,
 270                                 struct trailer_item **in_tok_last)
 271 {
 272         switch (arg_tok->conf.if_exists) {
 273         case EXISTS_DO_NOTHING:
 274                 free_trailer_item(arg_tok);
 275                 break;
 276         case EXISTS_REPLACE:
 277                 apply_item_command(in_tok, arg_tok);
 278                 add_arg_to_input_list(on_tok, arg_tok,
 279                                       in_tok_first, in_tok_last);
 280                 remove_from_list(in_tok, in_tok_first, in_tok_last);
 281                 free_trailer_item(in_tok);
 282                 break;
 283         case EXISTS_ADD:
 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                 break;
 288         case EXISTS_ADD_IF_DIFFERENT:
 289                 apply_item_command(in_tok, arg_tok);
 290                 if (check_if_different(in_tok, arg_tok, 1))
 291                         add_arg_to_input_list(on_tok, arg_tok,
 292                                               in_tok_first, in_tok_last);
 293                 else
 294                         free_trailer_item(arg_tok);
 295                 break;
 296         case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 297                 apply_item_command(in_tok, arg_tok);
 298                 if (check_if_different(on_tok, arg_tok, 0))
 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         }
 305 }
 306
 307 static void apply_arg_if_missing(struct trailer_item **in_tok_first,
 308                                  struct trailer_item **in_tok_last,
 309                                  struct trailer_item *arg_tok)
 310 {
 311         struct trailer_item **in_tok;
 312         enum action_where where;
 313
 314         switch (arg_tok->conf.if_missing) {
 315         case MISSING_DO_NOTHING:
 316                 free_trailer_item(arg_tok);
 317                 break;
 318         case MISSING_ADD:
 319                 where = arg_tok->conf.where;
 320                 in_tok = after_or_end(where) ? in_tok_last : in_tok_first;
 321                 apply_item_command(NULL, arg_tok);
 322                 if (*in_tok) {
 323                         add_arg_to_input_list(*in_tok, arg_tok,
 324                                               in_tok_first, in_tok_last);
 325                 } else {
 326                         *in_tok_first = arg_tok;
 327                         *in_tok_last = arg_tok;
 328                 }
 329                 break;
 330         }
 331 }
 332
 333 static int find_same_and_apply_arg(struct trailer_item **in_tok_first,
 334                                    struct trailer_item **in_tok_last,
 335                                    struct trailer_item *arg_tok)
 336 {
 337         struct trailer_item *in_tok;
 338         struct trailer_item *on_tok;
 339         struct trailer_item *following_tok;
 340
 341         enum action_where where = arg_tok->conf.where;
 342         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 343         int backwards = after_or_end(where);
 344         struct trailer_item *start_tok = backwards ? *in_tok_last : *in_tok_first;
 345
 346         for (in_tok = start_tok; in_tok; in_tok = following_tok) {
 347                 following_tok = backwards ? in_tok->previous : in_tok->next;
 348                 if (!same_token(in_tok, arg_tok))
 349                         continue;
 350                 on_tok = middle ? in_tok : start_tok;
 351                 apply_arg_if_exists(in_tok, arg_tok, on_tok,
 352                                     in_tok_first, in_tok_last);
 353                 return 1;
 354         }
 355         return 0;
 356 }
 357
 358 static void process_trailers_lists(struct trailer_item **in_tok_first,
 359                                    struct trailer_item **in_tok_last,
 360                                    struct trailer_item **arg_tok_first)
 361 {
 362         struct trailer_item *arg_tok;
 363         struct trailer_item *next_arg;
 364
 365         if (!*arg_tok_first)
 366                 return;
 367
 368         for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
 369                 int applied = 0;
 370
 371                 next_arg = arg_tok->next;
 372                 remove_from_list(arg_tok, arg_tok_first, NULL);
 373
 374                 applied = find_same_and_apply_arg(in_tok_first,
 375                                                   in_tok_last,
 376                                                   arg_tok);
 377
 378                 if (!applied)
 379                         apply_arg_if_missing(in_tok_first,
 380                                              in_tok_last,
 381                                              arg_tok);
 382         }
 383 }
 384
 385 static int set_where(struct conf_info *item, const char *value)
 386 {
 387         if (!strcasecmp("after", value))
 388                 item->where = WHERE_AFTER;
 389         else if (!strcasecmp("before", value))
 390                 item->where = WHERE_BEFORE;
 391         else if (!strcasecmp("end", value))
 392                 item->where = WHERE_END;
 393         else if (!strcasecmp("start", value))
 394                 item->where = WHERE_START;
 395         else
 396                 return -1;
 397         return 0;
 398 }
 399
 400 static int set_if_exists(struct conf_info *item, const char *value)
 401 {
 402         if (!strcasecmp("addIfDifferent", value))
 403                 item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 404         else if (!strcasecmp("addIfDifferentNeighbor", value))
 405                 item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 406         else if (!strcasecmp("add", value))
 407                 item->if_exists = EXISTS_ADD;
 408         else if (!strcasecmp("replace", value))
 409                 item->if_exists = EXISTS_REPLACE;
 410         else if (!strcasecmp("doNothing", value))
 411                 item->if_exists = EXISTS_DO_NOTHING;
 412         else
 413                 return -1;
 414         return 0;
 415 }
 416
 417 static int set_if_missing(struct conf_info *item, const char *value)
 418 {
 419         if (!strcasecmp("doNothing", value))
 420                 item->if_missing = MISSING_DO_NOTHING;
 421         else if (!strcasecmp("add", value))
 422                 item->if_missing = MISSING_ADD;
 423         else
 424                 return -1;
 425         return 0;
 426 }
 427
 428 static void duplicate_conf(struct conf_info *dst, struct conf_info *src)
 429 {
 430         *dst = *src;
 431         if (src->name)
 432                 dst->name = xstrdup(src->name);
 433         if (src->key)
 434                 dst->key = xstrdup(src->key);
 435         if (src->command)
 436                 dst->command = xstrdup(src->command);
 437 }
 438
 439 static struct trailer_item *get_conf_item(const char *name)
 440 {
 441         struct trailer_item *item;
 442         struct trailer_item *previous;
 443
 444         /* Look up item with same name */
 445         for (previous = NULL, item = first_conf_item;
 446              item;
 447              previous = item, item = item->next) {
 448                 if (!strcasecmp(item->conf.name, name))
 449                         return item;
 450         }
 451
 452         /* Item does not already exists, create it */
 453         item = xcalloc(sizeof(struct trailer_item), 1);
 454         duplicate_conf(&item->conf, &default_conf_info);
 455         item->conf.name = xstrdup(name);
 456
 457         if (!previous)
 458                 first_conf_item = item;
 459         else {
 460                 previous->next = item;
 461                 item->previous = previous;
 462         }
 463
 464         return item;
 465 }
 466
 467 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 468                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 469
 470 static struct {
 471         const char *name;
 472         enum trailer_info_type type;
 473 } trailer_config_items[] = {
 474         { "key", TRAILER_KEY },
 475         { "command", TRAILER_COMMAND },
 476         { "where", TRAILER_WHERE },
 477         { "ifexists", TRAILER_IF_EXISTS },
 478         { "ifmissing", TRAILER_IF_MISSING }
 479 };
 480
 481 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 482 {
 483         const char *trailer_item, *variable_name;
 484
 485         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 486                 return 0;
 487
 488         variable_name = strrchr(trailer_item, '.');
 489         if (!variable_name) {
 490                 if (!strcmp(trailer_item, "where")) {
 491                         if (set_where(&default_conf_info, value) < 0)
 492                                 warning(_("unknown value '%s' for key '%s'"),
 493                                         value, conf_key);
 494                 } else if (!strcmp(trailer_item, "ifexists")) {
 495                         if (set_if_exists(&default_conf_info, value) < 0)
 496                                 warning(_("unknown value '%s' for key '%s'"),
 497                                         value, conf_key);
 498                 } else if (!strcmp(trailer_item, "ifmissing")) {
 499                         if (set_if_missing(&default_conf_info, value) < 0)
 500                                 warning(_("unknown value '%s' for key '%s'"),
 501                                         value, conf_key);
 502                 } else if (!strcmp(trailer_item, "separators")) {
 503                         separators = xstrdup(value);
 504                 }
 505         }
 506         return 0;
 507 }
 508
 509 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 510 {
 511         const char *trailer_item, *variable_name;
 512         struct trailer_item *item;
 513         struct conf_info *conf;
 514         char *name = NULL;
 515         enum trailer_info_type type;
 516         int i;
 517
 518         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 519                 return 0;
 520
 521         variable_name = strrchr(trailer_item, '.');
 522         if (!variable_name)
 523                 return 0;
 524
 525         variable_name++;
 526         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 527                 if (strcmp(trailer_config_items[i].name, variable_name))
 528                         continue;
 529                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 530                 type = trailer_config_items[i].type;
 531                 break;
 532         }
 533
 534         if (!name)
 535                 return 0;
 536
 537         item = get_conf_item(name);
 538         conf = &item->conf;
 539         free(name);
 540
 541         switch (type) {
 542         case TRAILER_KEY:
 543                 if (conf->key)
 544                         warning(_("more than one %s"), conf_key);
 545                 conf->key = xstrdup(value);
 546                 break;
 547         case TRAILER_COMMAND:
 548                 if (conf->command)
 549                         warning(_("more than one %s"), conf_key);
 550                 conf->command = xstrdup(value);
 551                 break;
 552         case TRAILER_WHERE:
 553                 if (set_where(conf, value))
 554                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 555                 break;
 556         case TRAILER_IF_EXISTS:
 557                 if (set_if_exists(conf, value))
 558                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 559                 break;
 560         case TRAILER_IF_MISSING:
 561                 if (set_if_missing(conf, value))
 562                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 563                 break;
 564         default:
 565                 die("internal bug in trailer.c");
 566         }
 567         return 0;
 568 }
 569
 570 static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
 571 {
 572         size_t len;
 573         struct strbuf seps = STRBUF_INIT;
 574         strbuf_addstr(&seps, separators);
 575         strbuf_addch(&seps, '=');
 576         len = strcspn(trailer, seps.buf);
 577         strbuf_release(&seps);
 578         if (len == 0) {
 579                 int l = strlen(trailer);
 580                 while (l > 0 && isspace(trailer[l - 1]))
 581                         l--;
 582                 return error(_("empty trailer token in trailer '%.*s'"), l, trailer);
 583         }
 584         if (len < strlen(trailer)) {
 585                 strbuf_add(tok, trailer, len);
 586                 strbuf_trim(tok);
 587                 strbuf_addstr(val, trailer + len + 1);
 588                 strbuf_trim(val);
 589         } else {
 590                 strbuf_addstr(tok, trailer);
 591                 strbuf_trim(tok);
 592         }
 593         return 0;
 594 }
 595
 596 static const char *token_from_item(struct trailer_item *item, char *tok)
 597 {
 598         if (item->conf.key)
 599                 return item->conf.key;
 600         if (tok)
 601                 return tok;
 602         return item->conf.name;
 603 }
 604
 605 static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
 606                                              char *tok, char *val)
 607 {
 608         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 609         new->value = val ? val : xstrdup("");
 610
 611         if (conf_item) {
 612                 duplicate_conf(&new->conf, &conf_item->conf);
 613                 new->token = xstrdup(token_from_item(conf_item, tok));
 614                 free(tok);
 615         } else {
 616                 duplicate_conf(&new->conf, &default_conf_info);
 617                 new->token = tok;
 618         }
 619
 620         return new;
 621 }
 622
 623 static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
 624 {
 625         if (!strncasecmp(tok, item->conf.name, tok_len))
 626                 return 1;
 627         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 628 }
 629
 630 static struct trailer_item *create_trailer_item(const char *string)
 631 {
 632         struct strbuf tok = STRBUF_INIT;
 633         struct strbuf val = STRBUF_INIT;
 634         struct trailer_item *item;
 635         int tok_len;
 636
 637         if (parse_trailer(&tok, &val, string))
 638                 return NULL;
 639
 640         tok_len = token_len_without_separator(tok.buf, tok.len);
 641
 642         /* Lookup if the token matches something in the config */
 643         for (item = first_conf_item; item; item = item->next) {
 644                 if (token_matches_item(tok.buf, item, tok_len))
 645                         return new_trailer_item(item,
 646                                                 strbuf_detach(&tok, NULL),
 647                                                 strbuf_detach(&val, NULL));
 648         }
 649
 650         return new_trailer_item(NULL,
 651                                 strbuf_detach(&tok, NULL),
 652                                 strbuf_detach(&val, NULL));
 653 }
 654
 655 static void add_trailer_item(struct trailer_item **first,
 656                              struct trailer_item **last,
 657                              struct trailer_item *new)
 658 {
 659         if (!new)
 660                 return;
 661         if (!*last) {
 662                 *first = new;
 663                 *last = new;
 664         } else {
 665                 (*last)->next = new;
 666                 new->previous = *last;
 667                 *last = new;
 668         }
 669 }
 670
 671 static struct trailer_item *process_command_line_args(struct string_list *trailers)
 672 {
 673         struct trailer_item *arg_tok_first = NULL;
 674         struct trailer_item *arg_tok_last = NULL;
 675         struct string_list_item *tr;
 676         struct trailer_item *item;
 677
 678         /* Add a trailer item for each configured trailer with a command */
 679         for (item = first_conf_item; item; item = item->next) {
 680                 if (item->conf.command) {
 681                         struct trailer_item *new = new_trailer_item(item, NULL, NULL);
 682                         add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 683                 }
 684         }
 685
 686         /* Add a trailer item for each trailer on the command line */
 687         for_each_string_list_item(tr, trailers) {
 688                 struct trailer_item *new = create_trailer_item(tr->string);
 689                 add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 690         }
 691
 692         return arg_tok_first;
 693 }
 694
 695 static struct strbuf **read_input_file(const char *file)
 696 {
 697         struct strbuf **lines;
 698         struct strbuf sb = STRBUF_INIT;
 699
 700         if (file) {
 701                 if (strbuf_read_file(&sb, file, 0) < 0)
 702                         die_errno(_("could not read input file '%s'"), file);
 703         } else {
 704                 if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 705                         die_errno(_("could not read from stdin"));
 706         }
 707
 708         lines = strbuf_split(&sb, '\n');
 709
 710         strbuf_release(&sb);
 711
 712         return lines;
 713 }
 714
 715 /*
 716  * Return the (0 based) index of the start of the patch or the line
 717  * count if there is no patch in the message.
 718  */
 719 static int find_patch_start(struct strbuf **lines, int count)
 720 {
 721         int i;
 722
 723         /* Get the start of the patch part if any */
 724         for (i = 0; i < count; i++) {
 725                 if (starts_with(lines[i]->buf, "---"))
 726                         return i;
 727         }
 728
 729         return count;
 730 }
 731
 732 /*
 733  * Return the (0 based) index of the first trailer line or count if
 734  * there are no trailers. Trailers are searched only in the lines from
 735  * index (count - 1) down to index 0.
 736  */
 737 static int find_trailer_start(struct strbuf **lines, int count)
 738 {
 739         int start, end_of_title, only_spaces = 1;
 740
 741         /* The first paragraph is the title and cannot be trailers */
 742         for (start = 0; start < count; start++) {
 743                 if (lines[start]->buf[0] == comment_line_char)
 744                         continue;
 745                 if (contains_only_spaces(lines[start]->buf))
 746                         break;
 747         }
 748         end_of_title = start;
 749
 750         /*
 751          * Get the start of the trailers by looking starting from the end
 752          * for a line with only spaces before lines with one separator.
 753          */
 754         for (start = count - 1; start >= end_of_title; start--) {
 755                 if (lines[start]->buf[0] == comment_line_char)
 756                         continue;
 757                 if (contains_only_spaces(lines[start]->buf)) {
 758                         if (only_spaces)
 759                                 continue;
 760                         return start + 1;
 761                 }
 762                 if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 763                         if (only_spaces)
 764                                 only_spaces = 0;
 765                         continue;
 766                 }
 767                 return count;
 768         }
 769
 770         return only_spaces ? count : 0;
 771 }
 772
 773 /* Get the index of the end of the trailers */
 774 static int find_trailer_end(struct strbuf **lines, int patch_start)
 775 {
 776         struct strbuf sb = STRBUF_INIT;
 777         int i, ignore_bytes;
 778
 779         for (i = 0; i < patch_start; i++)
 780                 strbuf_addbuf(&sb, lines[i]);
 781         ignore_bytes = ignore_non_trailer(&sb);
 782         strbuf_release(&sb);
 783         for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 784                 ignore_bytes -= lines[i]->len;
 785
 786         return i + 1;
 787 }
 788
 789 static int has_blank_line_before(struct strbuf **lines, int start)
 790 {
 791         for (;start >= 0; start--) {
 792                 if (lines[start]->buf[0] == comment_line_char)
 793                         continue;
 794                 return contains_only_spaces(lines[start]->buf);
 795         }
 796         return 0;
 797 }
 798
 799 static void print_lines(FILE *outfile, struct strbuf **lines, int start, int end)
 800 {
 801         int i;
 802         for (i = start; lines[i] && i < end; i++)
 803                 fprintf(outfile, "%s", lines[i]->buf);
 804 }
 805
 806 static int process_input_file(FILE *outfile,
 807                               struct strbuf **lines,
 808                               struct trailer_item **in_tok_first,
 809                               struct trailer_item **in_tok_last)
 810 {
 811         int count = 0;
 812         int patch_start, trailer_start, trailer_end, i;
 813
 814         /* Get the line count */
 815         while (lines[count])
 816                 count++;
 817
 818         patch_start = find_patch_start(lines, count);
 819         trailer_end = find_trailer_end(lines, patch_start);
 820         trailer_start = find_trailer_start(lines, trailer_end);
 821
 822         /* Print lines before the trailers as is */
 823         print_lines(outfile, lines, 0, trailer_start);
 824
 825         if (!has_blank_line_before(lines, trailer_start - 1))
 826                 fprintf(outfile, "\n");
 827
 828         /* Parse trailer lines */
 829         for (i = trailer_start; i < trailer_end; i++) {
 830                 if (lines[i]->buf[0] != comment_line_char) {
 831                         struct trailer_item *new = create_trailer_item(lines[i]->buf);
 832                         add_trailer_item(in_tok_first, in_tok_last, new);
 833                 }
 834         }
 835
 836         return trailer_end;
 837 }
 838
 839 static void free_all(struct trailer_item **first)
 840 {
 841         while (*first) {
 842                 struct trailer_item *item = remove_first(first);
 843                 free_trailer_item(item);
 844         }
 845 }
 846
 847 static struct tempfile trailers_tempfile;
 848
 849 static FILE *create_in_place_tempfile(const char *file)
 850 {
 851         struct stat st;
 852         struct strbuf template = STRBUF_INIT;
 853         const char *tail;
 854         FILE *outfile;
 855
 856         if (stat(file, &st))
 857                 die_errno(_("could not stat %s"), file);
 858         if (!S_ISREG(st.st_mode))
 859                 die(_("file %s is not a regular file"), file);
 860         if (!(st.st_mode & S_IWUSR))
 861                 die(_("file %s is not writable by user"), file);
 862
 863         /* Create temporary file in the same directory as the original */
 864         tail = strrchr(file, '/');
 865         if (tail != NULL)
 866                 strbuf_add(&template, file, tail - file + 1);
 867         strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 868
 869         xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 870         strbuf_release(&template);
 871         outfile = fdopen_tempfile(&trailers_tempfile, "w");
 872         if (!outfile)
 873                 die_errno(_("could not open temporary file"));
 874
 875         return outfile;
 876 }
 877
 878 void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
 879 {
 880         struct trailer_item *in_tok_first = NULL;
 881         struct trailer_item *in_tok_last = NULL;
 882         struct trailer_item *arg_tok_first;
 883         struct strbuf **lines;
 884         int trailer_end;
 885         FILE *outfile = stdout;
 886
 887         /* Default config must be setup first */
 888         git_config(git_trailer_default_config, NULL);
 889         git_config(git_trailer_config, NULL);
 890
 891         lines = read_input_file(file);
 892
 893         if (in_place)
 894                 outfile = create_in_place_tempfile(file);
 895
 896         /* Print the lines before the trailers */
 897         trailer_end = process_input_file(outfile, lines, &in_tok_first, &in_tok_last);
 898
 899         arg_tok_first = process_command_line_args(trailers);
 900
 901         process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 902
 903         print_all(outfile, in_tok_first, trim_empty);
 904
 905         free_all(&in_tok_first);
 906
 907         /* Print the lines after the trailers as is */
 908         print_lines(outfile, lines, trailer_end, INT_MAX);
 909
 910         if (in_place)
 911                 if (rename_tempfile(&trailers_tempfile, file))
 912                         die_errno(_("could not rename temporary file to %s"), file);
 913
 914         strbuf_list_free(lines);
 915 }