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         dst->name = xstrdup_or_null(src->name);
 432         dst->key = xstrdup_or_null(src->key);
 433         dst->command = xstrdup_or_null(src->command);
 434 }
 435
 436 static struct trailer_item *get_conf_item(const char *name)
 437 {
 438         struct trailer_item *item;
 439         struct trailer_item *previous;
 440
 441         /* Look up item with same name */
 442         for (previous = NULL, item = first_conf_item;
 443              item;
 444              previous = item, item = item->next) {
 445                 if (!strcasecmp(item->conf.name, name))
 446                         return item;
 447         }
 448
 449         /* Item does not already exists, create it */
 450         item = xcalloc(sizeof(struct trailer_item), 1);
 451         duplicate_conf(&item->conf, &default_conf_info);
 452         item->conf.name = xstrdup(name);
 453
 454         if (!previous)
 455                 first_conf_item = item;
 456         else {
 457                 previous->next = item;
 458                 item->previous = previous;
 459         }
 460
 461         return item;
 462 }
 463
 464 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 465                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 466
 467 static struct {
 468         const char *name;
 469         enum trailer_info_type type;
 470 } trailer_config_items[] = {
 471         { "key", TRAILER_KEY },
 472         { "command", TRAILER_COMMAND },
 473         { "where", TRAILER_WHERE },
 474         { "ifexists", TRAILER_IF_EXISTS },
 475         { "ifmissing", TRAILER_IF_MISSING }
 476 };
 477
 478 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 479 {
 480         const char *trailer_item, *variable_name;
 481
 482         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 483                 return 0;
 484
 485         variable_name = strrchr(trailer_item, '.');
 486         if (!variable_name) {
 487                 if (!strcmp(trailer_item, "where")) {
 488                         if (set_where(&default_conf_info, value) < 0)
 489                                 warning(_("unknown value '%s' for key '%s'"),
 490                                         value, conf_key);
 491                 } else if (!strcmp(trailer_item, "ifexists")) {
 492                         if (set_if_exists(&default_conf_info, value) < 0)
 493                                 warning(_("unknown value '%s' for key '%s'"),
 494                                         value, conf_key);
 495                 } else if (!strcmp(trailer_item, "ifmissing")) {
 496                         if (set_if_missing(&default_conf_info, value) < 0)
 497                                 warning(_("unknown value '%s' for key '%s'"),
 498                                         value, conf_key);
 499                 } else if (!strcmp(trailer_item, "separators")) {
 500                         separators = xstrdup(value);
 501                 }
 502         }
 503         return 0;
 504 }
 505
 506 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 507 {
 508         const char *trailer_item, *variable_name;
 509         struct trailer_item *item;
 510         struct conf_info *conf;
 511         char *name = NULL;
 512         enum trailer_info_type type;
 513         int i;
 514
 515         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 516                 return 0;
 517
 518         variable_name = strrchr(trailer_item, '.');
 519         if (!variable_name)
 520                 return 0;
 521
 522         variable_name++;
 523         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 524                 if (strcmp(trailer_config_items[i].name, variable_name))
 525                         continue;
 526                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 527                 type = trailer_config_items[i].type;
 528                 break;
 529         }
 530
 531         if (!name)
 532                 return 0;
 533
 534         item = get_conf_item(name);
 535         conf = &item->conf;
 536         free(name);
 537
 538         switch (type) {
 539         case TRAILER_KEY:
 540                 if (conf->key)
 541                         warning(_("more than one %s"), conf_key);
 542                 conf->key = xstrdup(value);
 543                 break;
 544         case TRAILER_COMMAND:
 545                 if (conf->command)
 546                         warning(_("more than one %s"), conf_key);
 547                 conf->command = xstrdup(value);
 548                 break;
 549         case TRAILER_WHERE:
 550                 if (set_where(conf, value))
 551                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 552                 break;
 553         case TRAILER_IF_EXISTS:
 554                 if (set_if_exists(conf, value))
 555                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 556                 break;
 557         case TRAILER_IF_MISSING:
 558                 if (set_if_missing(conf, value))
 559                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 560                 break;
 561         default:
 562                 die("BUG: trailer.c: unhandled type %d", type);
 563         }
 564         return 0;
 565 }
 566
 567 static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
 568 {
 569         size_t len;
 570         struct strbuf seps = STRBUF_INIT;
 571         strbuf_addstr(&seps, separators);
 572         strbuf_addch(&seps, '=');
 573         len = strcspn(trailer, seps.buf);
 574         strbuf_release(&seps);
 575         if (len == 0) {
 576                 int l = strlen(trailer);
 577                 while (l > 0 && isspace(trailer[l - 1]))
 578                         l--;
 579                 return error(_("empty trailer token in trailer '%.*s'"), l, trailer);
 580         }
 581         if (len < strlen(trailer)) {
 582                 strbuf_add(tok, trailer, len);
 583                 strbuf_trim(tok);
 584                 strbuf_addstr(val, trailer + len + 1);
 585                 strbuf_trim(val);
 586         } else {
 587                 strbuf_addstr(tok, trailer);
 588                 strbuf_trim(tok);
 589         }
 590         return 0;
 591 }
 592
 593 static const char *token_from_item(struct trailer_item *item, char *tok)
 594 {
 595         if (item->conf.key)
 596                 return item->conf.key;
 597         if (tok)
 598                 return tok;
 599         return item->conf.name;
 600 }
 601
 602 static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
 603                                              char *tok, char *val)
 604 {
 605         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 606         new->value = val ? val : xstrdup("");
 607
 608         if (conf_item) {
 609                 duplicate_conf(&new->conf, &conf_item->conf);
 610                 new->token = xstrdup(token_from_item(conf_item, tok));
 611                 free(tok);
 612         } else {
 613                 duplicate_conf(&new->conf, &default_conf_info);
 614                 new->token = tok;
 615         }
 616
 617         return new;
 618 }
 619
 620 static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
 621 {
 622         if (!strncasecmp(tok, item->conf.name, tok_len))
 623                 return 1;
 624         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 625 }
 626
 627 static struct trailer_item *create_trailer_item(const char *string)
 628 {
 629         struct strbuf tok = STRBUF_INIT;
 630         struct strbuf val = STRBUF_INIT;
 631         struct trailer_item *item;
 632         int tok_len;
 633
 634         if (parse_trailer(&tok, &val, string))
 635                 return NULL;
 636
 637         tok_len = token_len_without_separator(tok.buf, tok.len);
 638
 639         /* Lookup if the token matches something in the config */
 640         for (item = first_conf_item; item; item = item->next) {
 641                 if (token_matches_item(tok.buf, item, tok_len))
 642                         return new_trailer_item(item,
 643                                                 strbuf_detach(&tok, NULL),
 644                                                 strbuf_detach(&val, NULL));
 645         }
 646
 647         return new_trailer_item(NULL,
 648                                 strbuf_detach(&tok, NULL),
 649                                 strbuf_detach(&val, NULL));
 650 }
 651
 652 static void add_trailer_item(struct trailer_item **first,
 653                              struct trailer_item **last,
 654                              struct trailer_item *new)
 655 {
 656         if (!new)
 657                 return;
 658         if (!*last) {
 659                 *first = new;
 660                 *last = new;
 661         } else {
 662                 (*last)->next = new;
 663                 new->previous = *last;
 664                 *last = new;
 665         }
 666 }
 667
 668 static struct trailer_item *process_command_line_args(struct string_list *trailers)
 669 {
 670         struct trailer_item *arg_tok_first = NULL;
 671         struct trailer_item *arg_tok_last = NULL;
 672         struct string_list_item *tr;
 673         struct trailer_item *item;
 674
 675         /* Add a trailer item for each configured trailer with a command */
 676         for (item = first_conf_item; item; item = item->next) {
 677                 if (item->conf.command) {
 678                         struct trailer_item *new = new_trailer_item(item, NULL, NULL);
 679                         add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 680                 }
 681         }
 682
 683         /* Add a trailer item for each trailer on the command line */
 684         for_each_string_list_item(tr, trailers) {
 685                 struct trailer_item *new = create_trailer_item(tr->string);
 686                 add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 687         }
 688
 689         return arg_tok_first;
 690 }
 691
 692 static struct strbuf **read_input_file(const char *file)
 693 {
 694         struct strbuf **lines;
 695         struct strbuf sb = STRBUF_INIT;
 696
 697         if (file) {
 698                 if (strbuf_read_file(&sb, file, 0) < 0)
 699                         die_errno(_("could not read input file '%s'"), file);
 700         } else {
 701                 if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 702                         die_errno(_("could not read from stdin"));
 703         }
 704
 705         lines = strbuf_split(&sb, '\n');
 706
 707         strbuf_release(&sb);
 708
 709         return lines;
 710 }
 711
 712 /*
 713  * Return the (0 based) index of the start of the patch or the line
 714  * count if there is no patch in the message.
 715  */
 716 static int find_patch_start(struct strbuf **lines, int count)
 717 {
 718         int i;
 719
 720         /* Get the start of the patch part if any */
 721         for (i = 0; i < count; i++) {
 722                 if (starts_with(lines[i]->buf, "---"))
 723                         return i;
 724         }
 725
 726         return count;
 727 }
 728
 729 /*
 730  * Return the (0 based) index of the first trailer line or count if
 731  * there are no trailers. Trailers are searched only in the lines from
 732  * index (count - 1) down to index 0.
 733  */
 734 static int find_trailer_start(struct strbuf **lines, int count)
 735 {
 736         int start, end_of_title, only_spaces = 1;
 737
 738         /* The first paragraph is the title and cannot be trailers */
 739         for (start = 0; start < count; start++) {
 740                 if (lines[start]->buf[0] == comment_line_char)
 741                         continue;
 742                 if (contains_only_spaces(lines[start]->buf))
 743                         break;
 744         }
 745         end_of_title = start;
 746
 747         /*
 748          * Get the start of the trailers by looking starting from the end
 749          * for a line with only spaces before lines with one separator.
 750          */
 751         for (start = count - 1; start >= end_of_title; start--) {
 752                 if (lines[start]->buf[0] == comment_line_char)
 753                         continue;
 754                 if (contains_only_spaces(lines[start]->buf)) {
 755                         if (only_spaces)
 756                                 continue;
 757                         return start + 1;
 758                 }
 759                 if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 760                         if (only_spaces)
 761                                 only_spaces = 0;
 762                         continue;
 763                 }
 764                 return count;
 765         }
 766
 767         return only_spaces ? count : 0;
 768 }
 769
 770 /* Get the index of the end of the trailers */
 771 static int find_trailer_end(struct strbuf **lines, int patch_start)
 772 {
 773         struct strbuf sb = STRBUF_INIT;
 774         int i, ignore_bytes;
 775
 776         for (i = 0; i < patch_start; i++)
 777                 strbuf_addbuf(&sb, lines[i]);
 778         ignore_bytes = ignore_non_trailer(&sb);
 779         strbuf_release(&sb);
 780         for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 781                 ignore_bytes -= lines[i]->len;
 782
 783         return i + 1;
 784 }
 785
 786 static int has_blank_line_before(struct strbuf **lines, int start)
 787 {
 788         for (;start >= 0; start--) {
 789                 if (lines[start]->buf[0] == comment_line_char)
 790                         continue;
 791                 return contains_only_spaces(lines[start]->buf);
 792         }
 793         return 0;
 794 }
 795
 796 static void print_lines(FILE *outfile, struct strbuf **lines, int start, int end)
 797 {
 798         int i;
 799         for (i = start; lines[i] && i < end; i++)
 800                 fprintf(outfile, "%s", lines[i]->buf);
 801 }
 802
 803 static int process_input_file(FILE *outfile,
 804                               struct strbuf **lines,
 805                               struct trailer_item **in_tok_first,
 806                               struct trailer_item **in_tok_last)
 807 {
 808         int count = 0;
 809         int patch_start, trailer_start, trailer_end, i;
 810
 811         /* Get the line count */
 812         while (lines[count])
 813                 count++;
 814
 815         patch_start = find_patch_start(lines, count);
 816         trailer_end = find_trailer_end(lines, patch_start);
 817         trailer_start = find_trailer_start(lines, trailer_end);
 818
 819         /* Print lines before the trailers as is */
 820         print_lines(outfile, lines, 0, trailer_start);
 821
 822         if (!has_blank_line_before(lines, trailer_start - 1))
 823                 fprintf(outfile, "\n");
 824
 825         /* Parse trailer lines */
 826         for (i = trailer_start; i < trailer_end; i++) {
 827                 if (lines[i]->buf[0] != comment_line_char) {
 828                         struct trailer_item *new = create_trailer_item(lines[i]->buf);
 829                         add_trailer_item(in_tok_first, in_tok_last, new);
 830                 }
 831         }
 832
 833         return trailer_end;
 834 }
 835
 836 static void free_all(struct trailer_item **first)
 837 {
 838         while (*first) {
 839                 struct trailer_item *item = remove_first(first);
 840                 free_trailer_item(item);
 841         }
 842 }
 843
 844 static struct tempfile trailers_tempfile;
 845
 846 static FILE *create_in_place_tempfile(const char *file)
 847 {
 848         struct stat st;
 849         struct strbuf template = STRBUF_INIT;
 850         const char *tail;
 851         FILE *outfile;
 852
 853         if (stat(file, &st))
 854                 die_errno(_("could not stat %s"), file);
 855         if (!S_ISREG(st.st_mode))
 856                 die(_("file %s is not a regular file"), file);
 857         if (!(st.st_mode & S_IWUSR))
 858                 die(_("file %s is not writable by user"), file);
 859
 860         /* Create temporary file in the same directory as the original */
 861         tail = strrchr(file, '/');
 862         if (tail != NULL)
 863                 strbuf_add(&template, file, tail - file + 1);
 864         strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 865
 866         xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 867         strbuf_release(&template);
 868         outfile = fdopen_tempfile(&trailers_tempfile, "w");
 869         if (!outfile)
 870                 die_errno(_("could not open temporary file"));
 871
 872         return outfile;
 873 }
 874
 875 void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
 876 {
 877         struct trailer_item *in_tok_first = NULL;
 878         struct trailer_item *in_tok_last = NULL;
 879         struct trailer_item *arg_tok_first;
 880         struct strbuf **lines;
 881         int trailer_end;
 882         FILE *outfile = stdout;
 883
 884         /* Default config must be setup first */
 885         git_config(git_trailer_default_config, NULL);
 886         git_config(git_trailer_config, NULL);
 887
 888         lines = read_input_file(file);
 889
 890         if (in_place)
 891                 outfile = create_in_place_tempfile(file);
 892
 893         /* Print the lines before the trailers */
 894         trailer_end = process_input_file(outfile, lines, &in_tok_first, &in_tok_last);
 895
 896         arg_tok_first = process_command_line_args(trailers);
 897
 898         process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 899
 900         print_all(outfile, in_tok_first, trim_empty);
 901
 902         free_all(&in_tok_first);
 903
 904         /* Print the lines after the trailers as is */
 905         print_lines(outfile, lines, trailer_end, INT_MAX);
 906
 907         if (in_place)
 908                 if (rename_tempfile(&trailers_tempfile, file))
 909                         die_errno(_("could not rename temporary file to %s"), file);
 910
 911         strbuf_list_free(lines);
 912 }