trailer.c

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "string-list.h"
   4 #include "run-command.h"
   5 #include "commit.h"
   6 #include "tempfile.h"
   7 #include "trailer.h"
   8 #include "list.h"
   9 /*
  10  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  11  */
  12
  13 struct conf_info {
  14         char *name;
  15         char *key;
  16         char *command;
  17         enum trailer_where where;
  18         enum trailer_if_exists if_exists;
  19         enum trailer_if_missing if_missing;
  20 };
  21
  22 static struct conf_info default_conf_info;
  23
  24 struct trailer_item {
  25         struct list_head list;
  26         /*
  27          * If this is not a trailer line, the line is stored in value
  28          * (excluding the terminating newline) and token is NULL.
  29          */
  30         char *token;
  31         char *value;
  32 };
  33
  34 struct arg_item {
  35         struct list_head list;
  36         char *token;
  37         char *value;
  38         struct conf_info conf;
  39 };
  40
  41 static LIST_HEAD(conf_head);
  42
  43 static char *separators = ":";
  44
  45 static int configured;
  46
  47 #define TRAILER_ARG_STRING "$ARG"
  48
  49 static const char *git_generated_prefixes[] = {
  50         "Signed-off-by: ",
  51         "(cherry picked from commit ",
  52         NULL
  53 };
  54
  55 /* Iterate over the elements of the list. */
  56 #define list_for_each_dir(pos, head, is_reverse) \
  57         for (pos = is_reverse ? (head)->prev : (head)->next; \
  58                 pos != (head); \
  59                 pos = is_reverse ? pos->prev : pos->next)
  60
  61 static int after_or_end(enum trailer_where where)
  62 {
  63         return (where == WHERE_AFTER) || (where == WHERE_END);
  64 }
  65
  66 /*
  67  * Return the length of the string not including any final
  68  * punctuation. E.g., the input "Signed-off-by:" would return
  69  * 13, stripping the trailing punctuation but retaining
  70  * internal punctuation.
  71  */
  72 static size_t token_len_without_separator(const char *token, size_t len)
  73 {
  74         while (len > 0 && !isalnum(token[len - 1]))
  75                 len--;
  76         return len;
  77 }
  78
  79 static int same_token(struct trailer_item *a, struct arg_item *b)
  80 {
  81         size_t a_len, b_len, min_len;
  82
  83         if (!a->token)
  84                 return 0;
  85
  86         a_len = token_len_without_separator(a->token, strlen(a->token));
  87         b_len = token_len_without_separator(b->token, strlen(b->token));
  88         min_len = (a_len > b_len) ? b_len : a_len;
  89
  90         return !strncasecmp(a->token, b->token, min_len);
  91 }
  92
  93 static int same_value(struct trailer_item *a, struct arg_item *b)
  94 {
  95         return !strcasecmp(a->value, b->value);
  96 }
  97
  98 static int same_trailer(struct trailer_item *a, struct arg_item *b)
  99 {
 100         return same_token(a, b) && same_value(a, b);
 101 }
 102
 103 static inline int is_blank_line(const char *str)
 104 {
 105         const char *s = str;
 106         while (*s && *s != '\n' && isspace(*s))
 107                 s++;
 108         return !*s || *s == '\n';
 109 }
 110
 111 static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
 112 {
 113         const char *ptr = strstr(sb->buf, a);
 114         if (ptr)
 115                 strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
 116 }
 117
 118 static void free_trailer_item(struct trailer_item *item)
 119 {
 120         free(item->token);
 121         free(item->value);
 122         free(item);
 123 }
 124
 125 static void free_arg_item(struct arg_item *item)
 126 {
 127         free(item->conf.name);
 128         free(item->conf.key);
 129         free(item->conf.command);
 130         free(item->token);
 131         free(item->value);
 132         free(item);
 133 }
 134
 135 static char last_non_space_char(const char *s)
 136 {
 137         int i;
 138         for (i = strlen(s) - 1; i >= 0; i--)
 139                 if (!isspace(s[i]))
 140                         return s[i];
 141         return '\0';
 142 }
 143
 144 static void print_tok_val(FILE *outfile, const char *tok, const char *val)
 145 {
 146         char c;
 147
 148         if (!tok) {
 149                 fprintf(outfile, "%s\n", val);
 150                 return;
 151         }
 152
 153         c = last_non_space_char(tok);
 154         if (!c)
 155                 return;
 156         if (strchr(separators, c))
 157                 fprintf(outfile, "%s%s\n", tok, val);
 158         else
 159                 fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 160 }
 161
 162 static void print_all(FILE *outfile, struct list_head *head, int trim_empty)
 163 {
 164         struct list_head *pos;
 165         struct trailer_item *item;
 166         list_for_each(pos, head) {
 167                 item = list_entry(pos, struct trailer_item, list);
 168                 if (!trim_empty || strlen(item->value) > 0)
 169                         print_tok_val(outfile, item->token, item->value);
 170         }
 171 }
 172
 173 static struct trailer_item *trailer_from_arg(struct arg_item *arg_tok)
 174 {
 175         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 176         new->token = arg_tok->token;
 177         new->value = arg_tok->value;
 178         arg_tok->token = arg_tok->value = NULL;
 179         free_arg_item(arg_tok);
 180         return new;
 181 }
 182
 183 static void add_arg_to_input_list(struct trailer_item *on_tok,
 184                                   struct arg_item *arg_tok)
 185 {
 186         int aoe = after_or_end(arg_tok->conf.where);
 187         struct trailer_item *to_add = trailer_from_arg(arg_tok);
 188         if (aoe)
 189                 list_add(&to_add->list, &on_tok->list);
 190         else
 191                 list_add_tail(&to_add->list, &on_tok->list);
 192 }
 193
 194 static int check_if_different(struct trailer_item *in_tok,
 195                               struct arg_item *arg_tok,
 196                               int check_all,
 197                               struct list_head *head)
 198 {
 199         enum trailer_where where = arg_tok->conf.where;
 200         struct list_head *next_head;
 201         do {
 202                 if (same_trailer(in_tok, arg_tok))
 203                         return 0;
 204                 /*
 205                  * if we want to add a trailer after another one,
 206                  * we have to check those before this one
 207                  */
 208                 next_head = after_or_end(where) ? in_tok->list.prev
 209                                                 : in_tok->list.next;
 210                 if (next_head == head)
 211                         break;
 212                 in_tok = list_entry(next_head, struct trailer_item, list);
 213         } while (check_all);
 214         return 1;
 215 }
 216
 217 static 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         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 arg_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 arg_item *arg_tok,
 267                                 struct trailer_item *on_tok,
 268                                 struct list_head *head)
 269 {
 270         switch (arg_tok->conf.if_exists) {
 271         case EXISTS_DO_NOTHING:
 272                 free_arg_item(arg_tok);
 273                 break;
 274         case EXISTS_REPLACE:
 275                 apply_item_command(in_tok, arg_tok);
 276                 add_arg_to_input_list(on_tok, arg_tok);
 277                 list_del(&in_tok->list);
 278                 free_trailer_item(in_tok);
 279                 break;
 280         case EXISTS_ADD:
 281                 apply_item_command(in_tok, arg_tok);
 282                 add_arg_to_input_list(on_tok, arg_tok);
 283                 break;
 284         case EXISTS_ADD_IF_DIFFERENT:
 285                 apply_item_command(in_tok, arg_tok);
 286                 if (check_if_different(in_tok, arg_tok, 1, head))
 287                         add_arg_to_input_list(on_tok, arg_tok);
 288                 else
 289                         free_arg_item(arg_tok);
 290                 break;
 291         case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 292                 apply_item_command(in_tok, arg_tok);
 293                 if (check_if_different(on_tok, arg_tok, 0, head))
 294                         add_arg_to_input_list(on_tok, arg_tok);
 295                 else
 296                         free_arg_item(arg_tok);
 297                 break;
 298         }
 299 }
 300
 301 static void apply_arg_if_missing(struct list_head *head,
 302                                  struct arg_item *arg_tok)
 303 {
 304         enum trailer_where where;
 305         struct trailer_item *to_add;
 306
 307         switch (arg_tok->conf.if_missing) {
 308         case MISSING_DO_NOTHING:
 309                 free_arg_item(arg_tok);
 310                 break;
 311         case MISSING_ADD:
 312                 where = arg_tok->conf.where;
 313                 apply_item_command(NULL, arg_tok);
 314                 to_add = trailer_from_arg(arg_tok);
 315                 if (after_or_end(where))
 316                         list_add_tail(&to_add->list, head);
 317                 else
 318                         list_add(&to_add->list, head);
 319         }
 320 }
 321
 322 static int find_same_and_apply_arg(struct list_head *head,
 323                                    struct arg_item *arg_tok)
 324 {
 325         struct list_head *pos;
 326         struct trailer_item *in_tok;
 327         struct trailer_item *on_tok;
 328
 329         enum trailer_where where = arg_tok->conf.where;
 330         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 331         int backwards = after_or_end(where);
 332         struct trailer_item *start_tok;
 333
 334         if (list_empty(head))
 335                 return 0;
 336
 337         start_tok = list_entry(backwards ? head->prev : head->next,
 338                                struct trailer_item,
 339                                list);
 340
 341         list_for_each_dir(pos, head, backwards) {
 342                 in_tok = list_entry(pos, struct trailer_item, list);
 343                 if (!same_token(in_tok, arg_tok))
 344                         continue;
 345                 on_tok = middle ? in_tok : start_tok;
 346                 apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 347                 return 1;
 348         }
 349         return 0;
 350 }
 351
 352 static void process_trailers_lists(struct list_head *head,
 353                                    struct list_head *arg_head)
 354 {
 355         struct list_head *pos, *p;
 356         struct arg_item *arg_tok;
 357
 358         list_for_each_safe(pos, p, arg_head) {
 359                 int applied = 0;
 360                 arg_tok = list_entry(pos, struct arg_item, list);
 361
 362                 list_del(pos);
 363
 364                 applied = find_same_and_apply_arg(head, arg_tok);
 365
 366                 if (!applied)
 367                         apply_arg_if_missing(head, arg_tok);
 368         }
 369 }
 370
 371 int trailer_set_where(enum trailer_where *item, const char *value)
 372 {
 373         if (!strcasecmp("after", value))
 374                 *item = WHERE_AFTER;
 375         else if (!strcasecmp("before", value))
 376                 *item = WHERE_BEFORE;
 377         else if (!strcasecmp("end", value))
 378                 *item = WHERE_END;
 379         else if (!strcasecmp("start", value))
 380                 *item = WHERE_START;
 381         else
 382                 return -1;
 383         return 0;
 384 }
 385
 386 int trailer_set_if_exists(enum trailer_if_exists *item, const char *value)
 387 {
 388         if (!strcasecmp("addIfDifferent", value))
 389                 *item = EXISTS_ADD_IF_DIFFERENT;
 390         else if (!strcasecmp("addIfDifferentNeighbor", value))
 391                 *item = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 392         else if (!strcasecmp("add", value))
 393                 *item = EXISTS_ADD;
 394         else if (!strcasecmp("replace", value))
 395                 *item = EXISTS_REPLACE;
 396         else if (!strcasecmp("doNothing", value))
 397                 *item = EXISTS_DO_NOTHING;
 398         else
 399                 return -1;
 400         return 0;
 401 }
 402
 403 int trailer_set_if_missing(enum trailer_if_missing *item, const char *value)
 404 {
 405         if (!strcasecmp("doNothing", value))
 406                 *item = MISSING_DO_NOTHING;
 407         else if (!strcasecmp("add", value))
 408                 *item = MISSING_ADD;
 409         else
 410                 return -1;
 411         return 0;
 412 }
 413
 414 static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 415 {
 416         *dst = *src;
 417         dst->name = xstrdup_or_null(src->name);
 418         dst->key = xstrdup_or_null(src->key);
 419         dst->command = xstrdup_or_null(src->command);
 420 }
 421
 422 static struct arg_item *get_conf_item(const char *name)
 423 {
 424         struct list_head *pos;
 425         struct arg_item *item;
 426
 427         /* Look up item with same name */
 428         list_for_each(pos, &conf_head) {
 429                 item = list_entry(pos, struct arg_item, list);
 430                 if (!strcasecmp(item->conf.name, name))
 431                         return item;
 432         }
 433
 434         /* Item does not already exists, create it */
 435         item = xcalloc(sizeof(*item), 1);
 436         duplicate_conf(&item->conf, &default_conf_info);
 437         item->conf.name = xstrdup(name);
 438
 439         list_add_tail(&item->list, &conf_head);
 440
 441         return item;
 442 }
 443
 444 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 445                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 446
 447 static struct {
 448         const char *name;
 449         enum trailer_info_type type;
 450 } trailer_config_items[] = {
 451         { "key", TRAILER_KEY },
 452         { "command", TRAILER_COMMAND },
 453         { "where", TRAILER_WHERE },
 454         { "ifexists", TRAILER_IF_EXISTS },
 455         { "ifmissing", TRAILER_IF_MISSING }
 456 };
 457
 458 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 459 {
 460         const char *trailer_item, *variable_name;
 461
 462         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 463                 return 0;
 464
 465         variable_name = strrchr(trailer_item, '.');
 466         if (!variable_name) {
 467                 if (!strcmp(trailer_item, "where")) {
 468                         if (trailer_set_where(&default_conf_info.where,
 469                                               value) < 0)
 470                                 warning(_("unknown value '%s' for key '%s'"),
 471                                         value, conf_key);
 472                 } else if (!strcmp(trailer_item, "ifexists")) {
 473                         if (trailer_set_if_exists(&default_conf_info.if_exists,
 474                                                   value) < 0)
 475                                 warning(_("unknown value '%s' for key '%s'"),
 476                                         value, conf_key);
 477                 } else if (!strcmp(trailer_item, "ifmissing")) {
 478                         if (trailer_set_if_missing(&default_conf_info.if_missing,
 479                                                    value) < 0)
 480                                 warning(_("unknown value '%s' for key '%s'"),
 481                                         value, conf_key);
 482                 } else if (!strcmp(trailer_item, "separators")) {
 483                         separators = xstrdup(value);
 484                 }
 485         }
 486         return 0;
 487 }
 488
 489 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 490 {
 491         const char *trailer_item, *variable_name;
 492         struct arg_item *item;
 493         struct conf_info *conf;
 494         char *name = NULL;
 495         enum trailer_info_type type;
 496         int i;
 497
 498         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 499                 return 0;
 500
 501         variable_name = strrchr(trailer_item, '.');
 502         if (!variable_name)
 503                 return 0;
 504
 505         variable_name++;
 506         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 507                 if (strcmp(trailer_config_items[i].name, variable_name))
 508                         continue;
 509                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 510                 type = trailer_config_items[i].type;
 511                 break;
 512         }
 513
 514         if (!name)
 515                 return 0;
 516
 517         item = get_conf_item(name);
 518         conf = &item->conf;
 519         free(name);
 520
 521         switch (type) {
 522         case TRAILER_KEY:
 523                 if (conf->key)
 524                         warning(_("more than one %s"), conf_key);
 525                 conf->key = xstrdup(value);
 526                 break;
 527         case TRAILER_COMMAND:
 528                 if (conf->command)
 529                         warning(_("more than one %s"), conf_key);
 530                 conf->command = xstrdup(value);
 531                 break;
 532         case TRAILER_WHERE:
 533                 if (trailer_set_where(&conf->where, value))
 534                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 535                 break;
 536         case TRAILER_IF_EXISTS:
 537                 if (trailer_set_if_exists(&conf->if_exists, value))
 538                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 539                 break;
 540         case TRAILER_IF_MISSING:
 541                 if (trailer_set_if_missing(&conf->if_missing, value))
 542                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 543                 break;
 544         default:
 545                 die("BUG: trailer.c: unhandled type %d", type);
 546         }
 547         return 0;
 548 }
 549
 550 static void ensure_configured(void)
 551 {
 552         if (configured)
 553                 return;
 554
 555         /* Default config must be setup first */
 556         default_conf_info.where = WHERE_END;
 557         default_conf_info.if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 558         default_conf_info.if_missing = MISSING_ADD;
 559         git_config(git_trailer_default_config, NULL);
 560         git_config(git_trailer_config, NULL);
 561         configured = 1;
 562 }
 563
 564 static const char *token_from_item(struct arg_item *item, char *tok)
 565 {
 566         if (item->conf.key)
 567                 return item->conf.key;
 568         if (tok)
 569                 return tok;
 570         return item->conf.name;
 571 }
 572
 573 static int token_matches_item(const char *tok, struct arg_item *item, int tok_len)
 574 {
 575         if (!strncasecmp(tok, item->conf.name, tok_len))
 576                 return 1;
 577         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 578 }
 579
 580 /*
 581  * If the given line is of the form
 582  * "<token><optional whitespace><separator>..." or "<separator>...", return the
 583  * location of the separator. Otherwise, return -1.  The optional whitespace
 584  * is allowed there primarily to allow things like "Bug #43" where <token> is
 585  * "Bug" and <separator> is "#".
 586  *
 587  * The separator-starts-line case (in which this function returns 0) is
 588  * distinguished from the non-well-formed-line case (in which this function
 589  * returns -1) because some callers of this function need such a distinction.
 590  */
 591 static int find_separator(const char *line, const char *separators)
 592 {
 593         int whitespace_found = 0;
 594         const char *c;
 595         for (c = line; *c; c++) {
 596                 if (strchr(separators, *c))
 597                         return c - line;
 598                 if (!whitespace_found && (isalnum(*c) || *c == '-'))
 599                         continue;
 600                 if (c != line && (*c == ' ' || *c == '\t')) {
 601                         whitespace_found = 1;
 602                         continue;
 603                 }
 604                 break;
 605         }
 606         return -1;
 607 }
 608
 609 /*
 610  * Obtain the token, value, and conf from the given trailer.
 611  *
 612  * separator_pos must not be 0, since the token cannot be an empty string.
 613  *
 614  * If separator_pos is -1, interpret the whole trailer as a token.
 615  */
 616 static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 617                          const struct conf_info **conf, const char *trailer,
 618                          int separator_pos)
 619 {
 620         struct arg_item *item;
 621         int tok_len;
 622         struct list_head *pos;
 623
 624         if (separator_pos != -1) {
 625                 strbuf_add(tok, trailer, separator_pos);
 626                 strbuf_trim(tok);
 627                 strbuf_addstr(val, trailer + separator_pos + 1);
 628                 strbuf_trim(val);
 629         } else {
 630                 strbuf_addstr(tok, trailer);
 631                 strbuf_trim(tok);
 632         }
 633
 634         /* Lookup if the token matches something in the config */
 635         tok_len = token_len_without_separator(tok->buf, tok->len);
 636         if (conf)
 637                 *conf = &default_conf_info;
 638         list_for_each(pos, &conf_head) {
 639                 item = list_entry(pos, struct arg_item, list);
 640                 if (token_matches_item(tok->buf, item, tok_len)) {
 641                         char *tok_buf = strbuf_detach(tok, NULL);
 642                         if (conf)
 643                                 *conf = &item->conf;
 644                         strbuf_addstr(tok, token_from_item(item, tok_buf));
 645                         free(tok_buf);
 646                         break;
 647                 }
 648         }
 649 }
 650
 651 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 652                                              char *val)
 653 {
 654         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 655         new->token = tok;
 656         new->value = val;
 657         list_add_tail(&new->list, head);
 658         return new;
 659 }
 660
 661 static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 662                          const struct conf_info *conf)
 663 {
 664         struct arg_item *new = xcalloc(sizeof(*new), 1);
 665         new->token = tok;
 666         new->value = val;
 667         duplicate_conf(&new->conf, conf);
 668         list_add_tail(&new->list, arg_head);
 669 }
 670
 671 static void process_command_line_args(struct list_head *arg_head,
 672                                       struct string_list *trailers)
 673 {
 674         struct string_list_item *tr;
 675         struct arg_item *item;
 676         struct strbuf tok = STRBUF_INIT;
 677         struct strbuf val = STRBUF_INIT;
 678         const struct conf_info *conf;
 679         struct list_head *pos;
 680
 681         /*
 682          * In command-line arguments, '=' is accepted (in addition to the
 683          * separators that are defined).
 684          */
 685         char *cl_separators = xstrfmt("=%s", separators);
 686
 687         /* Add an arg item for each configured trailer with a command */
 688         list_for_each(pos, &conf_head) {
 689                 item = list_entry(pos, struct arg_item, list);
 690                 if (item->conf.command)
 691                         add_arg_item(arg_head,
 692                                      xstrdup(token_from_item(item, NULL)),
 693                                      xstrdup(""),
 694                                      &item->conf);
 695         }
 696
 697         /* Add an arg item for each trailer on the command line */
 698         for_each_string_list_item(tr, trailers) {
 699                 int separator_pos = find_separator(tr->string, cl_separators);
 700                 if (separator_pos == 0) {
 701                         struct strbuf sb = STRBUF_INIT;
 702                         strbuf_addstr(&sb, tr->string);
 703                         strbuf_trim(&sb);
 704                         error(_("empty trailer token in trailer '%.*s'"),
 705                               (int) sb.len, sb.buf);
 706                         strbuf_release(&sb);
 707                 } else {
 708                         parse_trailer(&tok, &val, &conf, tr->string,
 709                                       separator_pos);
 710                         add_arg_item(arg_head,
 711                                      strbuf_detach(&tok, NULL),
 712                                      strbuf_detach(&val, NULL),
 713                                      conf);
 714                 }
 715         }
 716
 717         free(cl_separators);
 718 }
 719
 720 static void read_input_file(struct strbuf *sb, const char *file)
 721 {
 722         if (file) {
 723                 if (strbuf_read_file(sb, file, 0) < 0)
 724                         die_errno(_("could not read input file '%s'"), file);
 725         } else {
 726                 if (strbuf_read(sb, fileno(stdin), 0) < 0)
 727                         die_errno(_("could not read from stdin"));
 728         }
 729 }
 730
 731 static const char *next_line(const char *str)
 732 {
 733         const char *nl = strchrnul(str, '\n');
 734         return nl + !!*nl;
 735 }
 736
 737 /*
 738  * Return the position of the start of the last line. If len is 0, return -1.
 739  */
 740 static int last_line(const char *buf, size_t len)
 741 {
 742         int i;
 743         if (len == 0)
 744                 return -1;
 745         if (len == 1)
 746                 return 0;
 747         /*
 748          * Skip the last character (in addition to the null terminator),
 749          * because if the last character is a newline, it is considered as part
 750          * of the last line anyway.
 751          */
 752         i = len - 2;
 753
 754         for (; i >= 0; i--) {
 755                 if (buf[i] == '\n')
 756                         return i + 1;
 757         }
 758         return 0;
 759 }
 760
 761 /*
 762  * Return the position of the start of the patch or the length of str if there
 763  * is no patch in the message.
 764  */
 765 static int find_patch_start(const char *str)
 766 {
 767         const char *s;
 768
 769         for (s = str; *s; s = next_line(s)) {
 770                 if (starts_with(s, "---"))
 771                         return s - str;
 772         }
 773
 774         return s - str;
 775 }
 776
 777 /*
 778  * Return the position of the first trailer line or len if there are no
 779  * trailers.
 780  */
 781 static int find_trailer_start(const char *buf, size_t len)
 782 {
 783         const char *s;
 784         int end_of_title, l, only_spaces = 1;
 785         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 786         /*
 787          * Number of possible continuation lines encountered. This will be
 788          * reset to 0 if we encounter a trailer (since those lines are to be
 789          * considered continuations of that trailer), and added to
 790          * non_trailer_lines if we encounter a non-trailer (since those lines
 791          * are to be considered non-trailers).
 792          */
 793         int possible_continuation_lines = 0;
 794
 795         /* The first paragraph is the title and cannot be trailers */
 796         for (s = buf; s < buf + len; s = next_line(s)) {
 797                 if (s[0] == comment_line_char)
 798                         continue;
 799                 if (is_blank_line(s))
 800                         break;
 801         }
 802         end_of_title = s - buf;
 803
 804         /*
 805          * Get the start of the trailers by looking starting from the end for a
 806          * blank line before a set of non-blank lines that (i) are all
 807          * trailers, or (ii) contains at least one Git-generated trailer and
 808          * consists of at least 25% trailers.
 809          */
 810         for (l = last_line(buf, len);
 811              l >= end_of_title;
 812              l = last_line(buf, l)) {
 813                 const char *bol = buf + l;
 814                 const char **p;
 815                 int separator_pos;
 816
 817                 if (bol[0] == comment_line_char) {
 818                         non_trailer_lines += possible_continuation_lines;
 819                         possible_continuation_lines = 0;
 820                         continue;
 821                 }
 822                 if (is_blank_line(bol)) {
 823                         if (only_spaces)
 824                                 continue;
 825                         non_trailer_lines += possible_continuation_lines;
 826                         if (recognized_prefix &&
 827                             trailer_lines * 3 >= non_trailer_lines)
 828                                 return next_line(bol) - buf;
 829                         else if (trailer_lines && !non_trailer_lines)
 830                                 return next_line(bol) - buf;
 831                         return len;
 832                 }
 833                 only_spaces = 0;
 834
 835                 for (p = git_generated_prefixes; *p; p++) {
 836                         if (starts_with(bol, *p)) {
 837                                 trailer_lines++;
 838                                 possible_continuation_lines = 0;
 839                                 recognized_prefix = 1;
 840                                 goto continue_outer_loop;
 841                         }
 842                 }
 843
 844                 separator_pos = find_separator(bol, separators);
 845                 if (separator_pos >= 1 && !isspace(bol[0])) {
 846                         struct list_head *pos;
 847
 848                         trailer_lines++;
 849                         possible_continuation_lines = 0;
 850                         if (recognized_prefix)
 851                                 continue;
 852                         list_for_each(pos, &conf_head) {
 853                                 struct arg_item *item;
 854                                 item = list_entry(pos, struct arg_item, list);
 855                                 if (token_matches_item(bol, item,
 856                                                        separator_pos)) {
 857                                         recognized_prefix = 1;
 858                                         break;
 859                                 }
 860                         }
 861                 } else if (isspace(bol[0]))
 862                         possible_continuation_lines++;
 863                 else {
 864                         non_trailer_lines++;
 865                         non_trailer_lines += possible_continuation_lines;
 866                         possible_continuation_lines = 0;
 867                 }
 868 continue_outer_loop:
 869                 ;
 870         }
 871
 872         return len;
 873 }
 874
 875 /* Return the position of the end of the trailers. */
 876 static int find_trailer_end(const char *buf, size_t len)
 877 {
 878         return len - ignore_non_trailer(buf, len);
 879 }
 880
 881 static int ends_with_blank_line(const char *buf, size_t len)
 882 {
 883         int ll = last_line(buf, len);
 884         if (ll < 0)
 885                 return 0;
 886         return is_blank_line(buf + ll);
 887 }
 888
 889 static int process_input_file(FILE *outfile,
 890                               const char *str,
 891                               struct list_head *head)
 892 {
 893         struct trailer_info info;
 894         struct strbuf tok = STRBUF_INIT;
 895         struct strbuf val = STRBUF_INIT;
 896         int i;
 897
 898         trailer_info_get(&info, str);
 899
 900         /* Print lines before the trailers as is */
 901         fwrite(str, 1, info.trailer_start - str, outfile);
 902
 903         if (!info.blank_line_before_trailer)
 904                 fprintf(outfile, "\n");
 905
 906         for (i = 0; i < info.trailer_nr; i++) {
 907                 int separator_pos;
 908                 char *trailer = info.trailers[i];
 909                 if (trailer[0] == comment_line_char)
 910                         continue;
 911                 separator_pos = find_separator(trailer, separators);
 912                 if (separator_pos >= 1) {
 913                         parse_trailer(&tok, &val, NULL, trailer,
 914                                       separator_pos);
 915                         add_trailer_item(head,
 916                                          strbuf_detach(&tok, NULL),
 917                                          strbuf_detach(&val, NULL));
 918                 } else {
 919                         strbuf_addstr(&val, trailer);
 920                         strbuf_strip_suffix(&val, "\n");
 921                         add_trailer_item(head,
 922                                          NULL,
 923                                          strbuf_detach(&val, NULL));
 924                 }
 925         }
 926
 927         trailer_info_release(&info);
 928
 929         return info.trailer_end - str;
 930 }
 931
 932 static void free_all(struct list_head *head)
 933 {
 934         struct list_head *pos, *p;
 935         list_for_each_safe(pos, p, head) {
 936                 list_del(pos);
 937                 free_trailer_item(list_entry(pos, struct trailer_item, list));
 938         }
 939 }
 940
 941 static struct tempfile trailers_tempfile;
 942
 943 static FILE *create_in_place_tempfile(const char *file)
 944 {
 945         struct stat st;
 946         struct strbuf template = STRBUF_INIT;
 947         const char *tail;
 948         FILE *outfile;
 949
 950         if (stat(file, &st))
 951                 die_errno(_("could not stat %s"), file);
 952         if (!S_ISREG(st.st_mode))
 953                 die(_("file %s is not a regular file"), file);
 954         if (!(st.st_mode & S_IWUSR))
 955                 die(_("file %s is not writable by user"), file);
 956
 957         /* Create temporary file in the same directory as the original */
 958         tail = strrchr(file, '/');
 959         if (tail != NULL)
 960                 strbuf_add(&template, file, tail - file + 1);
 961         strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 962
 963         xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 964         strbuf_release(&template);
 965         outfile = fdopen_tempfile(&trailers_tempfile, "w");
 966         if (!outfile)
 967                 die_errno(_("could not open temporary file"));
 968
 969         return outfile;
 970 }
 971
 972 void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
 973 {
 974         LIST_HEAD(head);
 975         LIST_HEAD(arg_head);
 976         struct strbuf sb = STRBUF_INIT;
 977         int trailer_end;
 978         FILE *outfile = stdout;
 979
 980         ensure_configured();
 981
 982         read_input_file(&sb, file);
 983
 984         if (in_place)
 985                 outfile = create_in_place_tempfile(file);
 986
 987         /* Print the lines before the trailers */
 988         trailer_end = process_input_file(outfile, sb.buf, &head);
 989
 990         process_command_line_args(&arg_head, trailers);
 991
 992         process_trailers_lists(&head, &arg_head);
 993
 994         print_all(outfile, &head, trim_empty);
 995
 996         free_all(&head);
 997
 998         /* Print the lines after the trailers as is */
 999         fwrite(sb.buf + trailer_end, 1, sb.len - trailer_end, outfile);
1000
1001         if (in_place)
1002                 if (rename_tempfile(&trailers_tempfile, file))
1003                         die_errno(_("could not rename temporary file to %s"), file);
1004
1005         strbuf_release(&sb);
1006 }
1007
1008 void trailer_info_get(struct trailer_info *info, const char *str)
1009 {
1010         int patch_start, trailer_end, trailer_start;
1011         struct strbuf **trailer_lines, **ptr;
1012         char **trailer_strings = NULL;
1013         size_t nr = 0, alloc = 0;
1014         char **last = NULL;
1015
1016         ensure_configured();
1017
1018         patch_start = find_patch_start(str);
1019         trailer_end = find_trailer_end(str, patch_start);
1020         trailer_start = find_trailer_start(str, trailer_end);
1021
1022         trailer_lines = strbuf_split_buf(str + trailer_start,
1023                                          trailer_end - trailer_start,
1024                                          '\n',
1025                                          0);
1026         for (ptr = trailer_lines; *ptr; ptr++) {
1027                 if (last && isspace((*ptr)->buf[0])) {
1028                         struct strbuf sb = STRBUF_INIT;
1029                         strbuf_attach(&sb, *last, strlen(*last), strlen(*last));
1030                         strbuf_addbuf(&sb, *ptr);
1031                         *last = strbuf_detach(&sb, NULL);
1032                         continue;
1033                 }
1034                 ALLOC_GROW(trailer_strings, nr + 1, alloc);
1035                 trailer_strings[nr] = strbuf_detach(*ptr, NULL);
1036                 last = find_separator(trailer_strings[nr], separators) >= 1
1037                         ? &trailer_strings[nr]
1038                         : NULL;
1039                 nr++;
1040         }
1041         strbuf_list_free(trailer_lines);
1042
1043         info->blank_line_before_trailer = ends_with_blank_line(str,
1044                                                                trailer_start);
1045         info->trailer_start = str + trailer_start;
1046         info->trailer_end = str + trailer_end;
1047         info->trailers = trailer_strings;
1048         info->trailer_nr = nr;
1049 }
1050
1051 void trailer_info_release(struct trailer_info *info)
1052 {
1053         int i;
1054         for (i = 0; i < info->trailer_nr; i++)
1055                 free(info->trailers[i]);
1056         free(info->trailers);
1057 }