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         default:
 299                 die("BUG: trailer.c: unhandled value %d",
 300                     arg_tok->conf.if_exists);
 301         }
 302 }
 303
 304 static void apply_arg_if_missing(struct list_head *head,
 305                                  struct arg_item *arg_tok)
 306 {
 307         enum trailer_where where;
 308         struct trailer_item *to_add;
 309
 310         switch (arg_tok->conf.if_missing) {
 311         case MISSING_DO_NOTHING:
 312                 free_arg_item(arg_tok);
 313                 break;
 314         case MISSING_ADD:
 315                 where = arg_tok->conf.where;
 316                 apply_item_command(NULL, arg_tok);
 317                 to_add = trailer_from_arg(arg_tok);
 318                 if (after_or_end(where))
 319                         list_add_tail(&to_add->list, head);
 320                 else
 321                         list_add(&to_add->list, head);
 322                 break;
 323         default:
 324                 die("BUG: trailer.c: unhandled value %d",
 325                     arg_tok->conf.if_missing);
 326         }
 327 }
 328
 329 static int find_same_and_apply_arg(struct list_head *head,
 330                                    struct arg_item *arg_tok)
 331 {
 332         struct list_head *pos;
 333         struct trailer_item *in_tok;
 334         struct trailer_item *on_tok;
 335
 336         enum trailer_where where = arg_tok->conf.where;
 337         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 338         int backwards = after_or_end(where);
 339         struct trailer_item *start_tok;
 340
 341         if (list_empty(head))
 342                 return 0;
 343
 344         start_tok = list_entry(backwards ? head->prev : head->next,
 345                                struct trailer_item,
 346                                list);
 347
 348         list_for_each_dir(pos, head, backwards) {
 349                 in_tok = list_entry(pos, struct trailer_item, list);
 350                 if (!same_token(in_tok, arg_tok))
 351                         continue;
 352                 on_tok = middle ? in_tok : start_tok;
 353                 apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 354                 return 1;
 355         }
 356         return 0;
 357 }
 358
 359 static void process_trailers_lists(struct list_head *head,
 360                                    struct list_head *arg_head)
 361 {
 362         struct list_head *pos, *p;
 363         struct arg_item *arg_tok;
 364
 365         list_for_each_safe(pos, p, arg_head) {
 366                 int applied = 0;
 367                 arg_tok = list_entry(pos, struct arg_item, list);
 368
 369                 list_del(pos);
 370
 371                 applied = find_same_and_apply_arg(head, arg_tok);
 372
 373                 if (!applied)
 374                         apply_arg_if_missing(head, arg_tok);
 375         }
 376 }
 377
 378 int trailer_set_where(enum trailer_where *item, const char *value)
 379 {
 380         if (!value)
 381                 *item = WHERE_DEFAULT;
 382         else if (!strcasecmp("after", value))
 383                 *item = WHERE_AFTER;
 384         else if (!strcasecmp("before", value))
 385                 *item = WHERE_BEFORE;
 386         else if (!strcasecmp("end", value))
 387                 *item = WHERE_END;
 388         else if (!strcasecmp("start", value))
 389                 *item = WHERE_START;
 390         else
 391                 return -1;
 392         return 0;
 393 }
 394
 395 int trailer_set_if_exists(enum trailer_if_exists *item, const char *value)
 396 {
 397         if (!value)
 398                 *item = EXISTS_DEFAULT;
 399         else if (!strcasecmp("addIfDifferent", value))
 400                 *item = EXISTS_ADD_IF_DIFFERENT;
 401         else if (!strcasecmp("addIfDifferentNeighbor", value))
 402                 *item = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 403         else if (!strcasecmp("add", value))
 404                 *item = EXISTS_ADD;
 405         else if (!strcasecmp("replace", value))
 406                 *item = EXISTS_REPLACE;
 407         else if (!strcasecmp("doNothing", value))
 408                 *item = EXISTS_DO_NOTHING;
 409         else
 410                 return -1;
 411         return 0;
 412 }
 413
 414 int trailer_set_if_missing(enum trailer_if_missing *item, const char *value)
 415 {
 416         if (!value)
 417                 *item = MISSING_DEFAULT;
 418         else if (!strcasecmp("doNothing", value))
 419                 *item = MISSING_DO_NOTHING;
 420         else if (!strcasecmp("add", value))
 421                 *item = MISSING_ADD;
 422         else
 423                 return -1;
 424         return 0;
 425 }
 426
 427 static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 428 {
 429         *dst = *src;
 430         dst->name = xstrdup_or_null(src->name);
 431         dst->key = xstrdup_or_null(src->key);
 432         dst->command = xstrdup_or_null(src->command);
 433 }
 434
 435 static struct arg_item *get_conf_item(const char *name)
 436 {
 437         struct list_head *pos;
 438         struct arg_item *item;
 439
 440         /* Look up item with same name */
 441         list_for_each(pos, &conf_head) {
 442                 item = list_entry(pos, struct arg_item, list);
 443                 if (!strcasecmp(item->conf.name, name))
 444                         return item;
 445         }
 446
 447         /* Item does not already exists, create it */
 448         item = xcalloc(sizeof(*item), 1);
 449         duplicate_conf(&item->conf, &default_conf_info);
 450         item->conf.name = xstrdup(name);
 451
 452         list_add_tail(&item->list, &conf_head);
 453
 454         return item;
 455 }
 456
 457 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 458                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 459
 460 static struct {
 461         const char *name;
 462         enum trailer_info_type type;
 463 } trailer_config_items[] = {
 464         { "key", TRAILER_KEY },
 465         { "command", TRAILER_COMMAND },
 466         { "where", TRAILER_WHERE },
 467         { "ifexists", TRAILER_IF_EXISTS },
 468         { "ifmissing", TRAILER_IF_MISSING }
 469 };
 470
 471 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 472 {
 473         const char *trailer_item, *variable_name;
 474
 475         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 476                 return 0;
 477
 478         variable_name = strrchr(trailer_item, '.');
 479         if (!variable_name) {
 480                 if (!strcmp(trailer_item, "where")) {
 481                         if (trailer_set_where(&default_conf_info.where,
 482                                               value) < 0)
 483                                 warning(_("unknown value '%s' for key '%s'"),
 484                                         value, conf_key);
 485                 } else if (!strcmp(trailer_item, "ifexists")) {
 486                         if (trailer_set_if_exists(&default_conf_info.if_exists,
 487                                                   value) < 0)
 488                                 warning(_("unknown value '%s' for key '%s'"),
 489                                         value, conf_key);
 490                 } else if (!strcmp(trailer_item, "ifmissing")) {
 491                         if (trailer_set_if_missing(&default_conf_info.if_missing,
 492                                                    value) < 0)
 493                                 warning(_("unknown value '%s' for key '%s'"),
 494                                         value, conf_key);
 495                 } else if (!strcmp(trailer_item, "separators")) {
 496                         separators = xstrdup(value);
 497                 }
 498         }
 499         return 0;
 500 }
 501
 502 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 503 {
 504         const char *trailer_item, *variable_name;
 505         struct arg_item *item;
 506         struct conf_info *conf;
 507         char *name = NULL;
 508         enum trailer_info_type type;
 509         int i;
 510
 511         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 512                 return 0;
 513
 514         variable_name = strrchr(trailer_item, '.');
 515         if (!variable_name)
 516                 return 0;
 517
 518         variable_name++;
 519         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 520                 if (strcmp(trailer_config_items[i].name, variable_name))
 521                         continue;
 522                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 523                 type = trailer_config_items[i].type;
 524                 break;
 525         }
 526
 527         if (!name)
 528                 return 0;
 529
 530         item = get_conf_item(name);
 531         conf = &item->conf;
 532         free(name);
 533
 534         switch (type) {
 535         case TRAILER_KEY:
 536                 if (conf->key)
 537                         warning(_("more than one %s"), conf_key);
 538                 conf->key = xstrdup(value);
 539                 break;
 540         case TRAILER_COMMAND:
 541                 if (conf->command)
 542                         warning(_("more than one %s"), conf_key);
 543                 conf->command = xstrdup(value);
 544                 break;
 545         case TRAILER_WHERE:
 546                 if (trailer_set_where(&conf->where, value))
 547                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 548                 break;
 549         case TRAILER_IF_EXISTS:
 550                 if (trailer_set_if_exists(&conf->if_exists, value))
 551                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 552                 break;
 553         case TRAILER_IF_MISSING:
 554                 if (trailer_set_if_missing(&conf->if_missing, value))
 555                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 556                 break;
 557         default:
 558                 die("BUG: trailer.c: unhandled type %d", type);
 559         }
 560         return 0;
 561 }
 562
 563 static void ensure_configured(void)
 564 {
 565         if (configured)
 566                 return;
 567
 568         /* Default config must be setup first */
 569         default_conf_info.where = WHERE_END;
 570         default_conf_info.if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 571         default_conf_info.if_missing = MISSING_ADD;
 572         git_config(git_trailer_default_config, NULL);
 573         git_config(git_trailer_config, NULL);
 574         configured = 1;
 575 }
 576
 577 static const char *token_from_item(struct arg_item *item, char *tok)
 578 {
 579         if (item->conf.key)
 580                 return item->conf.key;
 581         if (tok)
 582                 return tok;
 583         return item->conf.name;
 584 }
 585
 586 static int token_matches_item(const char *tok, struct arg_item *item, int tok_len)
 587 {
 588         if (!strncasecmp(tok, item->conf.name, tok_len))
 589                 return 1;
 590         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 591 }
 592
 593 /*
 594  * If the given line is of the form
 595  * "<token><optional whitespace><separator>..." or "<separator>...", return the
 596  * location of the separator. Otherwise, return -1.  The optional whitespace
 597  * is allowed there primarily to allow things like "Bug #43" where <token> is
 598  * "Bug" and <separator> is "#".
 599  *
 600  * The separator-starts-line case (in which this function returns 0) is
 601  * distinguished from the non-well-formed-line case (in which this function
 602  * returns -1) because some callers of this function need such a distinction.
 603  */
 604 static int find_separator(const char *line, const char *separators)
 605 {
 606         int whitespace_found = 0;
 607         const char *c;
 608         for (c = line; *c; c++) {
 609                 if (strchr(separators, *c))
 610                         return c - line;
 611                 if (!whitespace_found && (isalnum(*c) || *c == '-'))
 612                         continue;
 613                 if (c != line && (*c == ' ' || *c == '\t')) {
 614                         whitespace_found = 1;
 615                         continue;
 616                 }
 617                 break;
 618         }
 619         return -1;
 620 }
 621
 622 /*
 623  * Obtain the token, value, and conf from the given trailer.
 624  *
 625  * separator_pos must not be 0, since the token cannot be an empty string.
 626  *
 627  * If separator_pos is -1, interpret the whole trailer as a token.
 628  */
 629 static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 630                          const struct conf_info **conf, const char *trailer,
 631                          int separator_pos)
 632 {
 633         struct arg_item *item;
 634         int tok_len;
 635         struct list_head *pos;
 636
 637         if (separator_pos != -1) {
 638                 strbuf_add(tok, trailer, separator_pos);
 639                 strbuf_trim(tok);
 640                 strbuf_addstr(val, trailer + separator_pos + 1);
 641                 strbuf_trim(val);
 642         } else {
 643                 strbuf_addstr(tok, trailer);
 644                 strbuf_trim(tok);
 645         }
 646
 647         /* Lookup if the token matches something in the config */
 648         tok_len = token_len_without_separator(tok->buf, tok->len);
 649         if (conf)
 650                 *conf = &default_conf_info;
 651         list_for_each(pos, &conf_head) {
 652                 item = list_entry(pos, struct arg_item, list);
 653                 if (token_matches_item(tok->buf, item, tok_len)) {
 654                         char *tok_buf = strbuf_detach(tok, NULL);
 655                         if (conf)
 656                                 *conf = &item->conf;
 657                         strbuf_addstr(tok, token_from_item(item, tok_buf));
 658                         free(tok_buf);
 659                         break;
 660                 }
 661         }
 662 }
 663
 664 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 665                                              char *val)
 666 {
 667         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 668         new->token = tok;
 669         new->value = val;
 670         list_add_tail(&new->list, head);
 671         return new;
 672 }
 673
 674 static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 675                          const struct conf_info *conf,
 676                          const struct new_trailer_item *new_trailer_item)
 677 {
 678         struct arg_item *new = xcalloc(sizeof(*new), 1);
 679         new->token = tok;
 680         new->value = val;
 681         duplicate_conf(&new->conf, conf);
 682         if (new_trailer_item) {
 683                 if (new_trailer_item->where != WHERE_DEFAULT)
 684                         new->conf.where = new_trailer_item->where;
 685                 if (new_trailer_item->if_exists != EXISTS_DEFAULT)
 686                         new->conf.if_exists = new_trailer_item->if_exists;
 687                 if (new_trailer_item->if_missing != MISSING_DEFAULT)
 688                         new->conf.if_missing = new_trailer_item->if_missing;
 689         }
 690         list_add_tail(&new->list, arg_head);
 691 }
 692
 693 static void process_command_line_args(struct list_head *arg_head,
 694                                       struct list_head *new_trailer_head)
 695 {
 696         struct arg_item *item;
 697         struct strbuf tok = STRBUF_INIT;
 698         struct strbuf val = STRBUF_INIT;
 699         const struct conf_info *conf;
 700         struct list_head *pos;
 701
 702         /*
 703          * In command-line arguments, '=' is accepted (in addition to the
 704          * separators that are defined).
 705          */
 706         char *cl_separators = xstrfmt("=%s", separators);
 707
 708         /* Add an arg item for each configured trailer with a command */
 709         list_for_each(pos, &conf_head) {
 710                 item = list_entry(pos, struct arg_item, list);
 711                 if (item->conf.command)
 712                         add_arg_item(arg_head,
 713                                      xstrdup(token_from_item(item, NULL)),
 714                                      xstrdup(""),
 715                                      &item->conf, NULL);
 716         }
 717
 718         /* Add an arg item for each trailer on the command line */
 719         list_for_each(pos, new_trailer_head) {
 720                 struct new_trailer_item *tr =
 721                         list_entry(pos, struct new_trailer_item, list);
 722                 int separator_pos = find_separator(tr->text, cl_separators);
 723
 724                 if (separator_pos == 0) {
 725                         struct strbuf sb = STRBUF_INIT;
 726                         strbuf_addstr(&sb, tr->text);
 727                         strbuf_trim(&sb);
 728                         error(_("empty trailer token in trailer '%.*s'"),
 729                               (int) sb.len, sb.buf);
 730                         strbuf_release(&sb);
 731                 } else {
 732                         parse_trailer(&tok, &val, &conf, tr->text,
 733                                       separator_pos);
 734                         add_arg_item(arg_head,
 735                                      strbuf_detach(&tok, NULL),
 736                                      strbuf_detach(&val, NULL),
 737                                      conf, tr);
 738                 }
 739         }
 740
 741         free(cl_separators);
 742 }
 743
 744 static void read_input_file(struct strbuf *sb, const char *file)
 745 {
 746         if (file) {
 747                 if (strbuf_read_file(sb, file, 0) < 0)
 748                         die_errno(_("could not read input file '%s'"), file);
 749         } else {
 750                 if (strbuf_read(sb, fileno(stdin), 0) < 0)
 751                         die_errno(_("could not read from stdin"));
 752         }
 753 }
 754
 755 static const char *next_line(const char *str)
 756 {
 757         const char *nl = strchrnul(str, '\n');
 758         return nl + !!*nl;
 759 }
 760
 761 /*
 762  * Return the position of the start of the last line. If len is 0, return -1.
 763  */
 764 static int last_line(const char *buf, size_t len)
 765 {
 766         int i;
 767         if (len == 0)
 768                 return -1;
 769         if (len == 1)
 770                 return 0;
 771         /*
 772          * Skip the last character (in addition to the null terminator),
 773          * because if the last character is a newline, it is considered as part
 774          * of the last line anyway.
 775          */
 776         i = len - 2;
 777
 778         for (; i >= 0; i--) {
 779                 if (buf[i] == '\n')
 780                         return i + 1;
 781         }
 782         return 0;
 783 }
 784
 785 /*
 786  * Return the position of the start of the patch or the length of str if there
 787  * is no patch in the message.
 788  */
 789 static int find_patch_start(const char *str)
 790 {
 791         const char *s;
 792
 793         for (s = str; *s; s = next_line(s)) {
 794                 if (starts_with(s, "---"))
 795                         return s - str;
 796         }
 797
 798         return s - str;
 799 }
 800
 801 /*
 802  * Return the position of the first trailer line or len if there are no
 803  * trailers.
 804  */
 805 static int find_trailer_start(const char *buf, size_t len)
 806 {
 807         const char *s;
 808         int end_of_title, l, only_spaces = 1;
 809         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 810         /*
 811          * Number of possible continuation lines encountered. This will be
 812          * reset to 0 if we encounter a trailer (since those lines are to be
 813          * considered continuations of that trailer), and added to
 814          * non_trailer_lines if we encounter a non-trailer (since those lines
 815          * are to be considered non-trailers).
 816          */
 817         int possible_continuation_lines = 0;
 818
 819         /* The first paragraph is the title and cannot be trailers */
 820         for (s = buf; s < buf + len; s = next_line(s)) {
 821                 if (s[0] == comment_line_char)
 822                         continue;
 823                 if (is_blank_line(s))
 824                         break;
 825         }
 826         end_of_title = s - buf;
 827
 828         /*
 829          * Get the start of the trailers by looking starting from the end for a
 830          * blank line before a set of non-blank lines that (i) are all
 831          * trailers, or (ii) contains at least one Git-generated trailer and
 832          * consists of at least 25% trailers.
 833          */
 834         for (l = last_line(buf, len);
 835              l >= end_of_title;
 836              l = last_line(buf, l)) {
 837                 const char *bol = buf + l;
 838                 const char **p;
 839                 int separator_pos;
 840
 841                 if (bol[0] == comment_line_char) {
 842                         non_trailer_lines += possible_continuation_lines;
 843                         possible_continuation_lines = 0;
 844                         continue;
 845                 }
 846                 if (is_blank_line(bol)) {
 847                         if (only_spaces)
 848                                 continue;
 849                         non_trailer_lines += possible_continuation_lines;
 850                         if (recognized_prefix &&
 851                             trailer_lines * 3 >= non_trailer_lines)
 852                                 return next_line(bol) - buf;
 853                         else if (trailer_lines && !non_trailer_lines)
 854                                 return next_line(bol) - buf;
 855                         return len;
 856                 }
 857                 only_spaces = 0;
 858
 859                 for (p = git_generated_prefixes; *p; p++) {
 860                         if (starts_with(bol, *p)) {
 861                                 trailer_lines++;
 862                                 possible_continuation_lines = 0;
 863                                 recognized_prefix = 1;
 864                                 goto continue_outer_loop;
 865                         }
 866                 }
 867
 868                 separator_pos = find_separator(bol, separators);
 869                 if (separator_pos >= 1 && !isspace(bol[0])) {
 870                         struct list_head *pos;
 871
 872                         trailer_lines++;
 873                         possible_continuation_lines = 0;
 874                         if (recognized_prefix)
 875                                 continue;
 876                         list_for_each(pos, &conf_head) {
 877                                 struct arg_item *item;
 878                                 item = list_entry(pos, struct arg_item, list);
 879                                 if (token_matches_item(bol, item,
 880                                                        separator_pos)) {
 881                                         recognized_prefix = 1;
 882                                         break;
 883                                 }
 884                         }
 885                 } else if (isspace(bol[0]))
 886                         possible_continuation_lines++;
 887                 else {
 888                         non_trailer_lines++;
 889                         non_trailer_lines += possible_continuation_lines;
 890                         possible_continuation_lines = 0;
 891                 }
 892 continue_outer_loop:
 893                 ;
 894         }
 895
 896         return len;
 897 }
 898
 899 /* Return the position of the end of the trailers. */
 900 static int find_trailer_end(const char *buf, size_t len)
 901 {
 902         return len - ignore_non_trailer(buf, len);
 903 }
 904
 905 static int ends_with_blank_line(const char *buf, size_t len)
 906 {
 907         int ll = last_line(buf, len);
 908         if (ll < 0)
 909                 return 0;
 910         return is_blank_line(buf + ll);
 911 }
 912
 913 static int process_input_file(FILE *outfile,
 914                               const char *str,
 915                               struct list_head *head)
 916 {
 917         struct trailer_info info;
 918         struct strbuf tok = STRBUF_INIT;
 919         struct strbuf val = STRBUF_INIT;
 920         int i;
 921
 922         trailer_info_get(&info, str);
 923
 924         /* Print lines before the trailers as is */
 925         fwrite(str, 1, info.trailer_start - str, outfile);
 926
 927         if (!info.blank_line_before_trailer)
 928                 fprintf(outfile, "\n");
 929
 930         for (i = 0; i < info.trailer_nr; i++) {
 931                 int separator_pos;
 932                 char *trailer = info.trailers[i];
 933                 if (trailer[0] == comment_line_char)
 934                         continue;
 935                 separator_pos = find_separator(trailer, separators);
 936                 if (separator_pos >= 1) {
 937                         parse_trailer(&tok, &val, NULL, trailer,
 938                                       separator_pos);
 939                         add_trailer_item(head,
 940                                          strbuf_detach(&tok, NULL),
 941                                          strbuf_detach(&val, NULL));
 942                 } else {
 943                         strbuf_addstr(&val, trailer);
 944                         strbuf_strip_suffix(&val, "\n");
 945                         add_trailer_item(head,
 946                                          NULL,
 947                                          strbuf_detach(&val, NULL));
 948                 }
 949         }
 950
 951         trailer_info_release(&info);
 952
 953         return info.trailer_end - str;
 954 }
 955
 956 static void free_all(struct list_head *head)
 957 {
 958         struct list_head *pos, *p;
 959         list_for_each_safe(pos, p, head) {
 960                 list_del(pos);
 961                 free_trailer_item(list_entry(pos, struct trailer_item, list));
 962         }
 963 }
 964
 965 static struct tempfile trailers_tempfile;
 966
 967 static FILE *create_in_place_tempfile(const char *file)
 968 {
 969         struct stat st;
 970         struct strbuf template = STRBUF_INIT;
 971         const char *tail;
 972         FILE *outfile;
 973
 974         if (stat(file, &st))
 975                 die_errno(_("could not stat %s"), file);
 976         if (!S_ISREG(st.st_mode))
 977                 die(_("file %s is not a regular file"), file);
 978         if (!(st.st_mode & S_IWUSR))
 979                 die(_("file %s is not writable by user"), file);
 980
 981         /* Create temporary file in the same directory as the original */
 982         tail = strrchr(file, '/');
 983         if (tail != NULL)
 984                 strbuf_add(&template, file, tail - file + 1);
 985         strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 986
 987         xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 988         strbuf_release(&template);
 989         outfile = fdopen_tempfile(&trailers_tempfile, "w");
 990         if (!outfile)
 991                 die_errno(_("could not open temporary file"));
 992
 993         return outfile;
 994 }
 995
 996 void process_trailers(const char *file, int in_place, int trim_empty,
 997                       struct list_head *new_trailer_head)
 998 {
 999         LIST_HEAD(head);
1000         LIST_HEAD(arg_head);
1001         struct strbuf sb = STRBUF_INIT;
1002         int trailer_end;
1003         FILE *outfile = stdout;
1004
1005         ensure_configured();
1006
1007         read_input_file(&sb, file);
1008
1009         if (in_place)
1010                 outfile = create_in_place_tempfile(file);
1011
1012         /* Print the lines before the trailers */
1013         trailer_end = process_input_file(outfile, sb.buf, &head);
1014
1015         process_command_line_args(&arg_head, new_trailer_head);
1016
1017         process_trailers_lists(&head, &arg_head);
1018
1019         print_all(outfile, &head, trim_empty);
1020
1021         free_all(&head);
1022
1023         /* Print the lines after the trailers as is */
1024         fwrite(sb.buf + trailer_end, 1, sb.len - trailer_end, outfile);
1025
1026         if (in_place)
1027                 if (rename_tempfile(&trailers_tempfile, file))
1028                         die_errno(_("could not rename temporary file to %s"), file);
1029
1030         strbuf_release(&sb);
1031 }
1032
1033 void trailer_info_get(struct trailer_info *info, const char *str)
1034 {
1035         int patch_start, trailer_end, trailer_start;
1036         struct strbuf **trailer_lines, **ptr;
1037         char **trailer_strings = NULL;
1038         size_t nr = 0, alloc = 0;
1039         char **last = NULL;
1040
1041         ensure_configured();
1042
1043         patch_start = find_patch_start(str);
1044         trailer_end = find_trailer_end(str, patch_start);
1045         trailer_start = find_trailer_start(str, trailer_end);
1046
1047         trailer_lines = strbuf_split_buf(str + trailer_start,
1048                                          trailer_end - trailer_start,
1049                                          '\n',
1050                                          0);
1051         for (ptr = trailer_lines; *ptr; ptr++) {
1052                 if (last && isspace((*ptr)->buf[0])) {
1053                         struct strbuf sb = STRBUF_INIT;
1054                         strbuf_attach(&sb, *last, strlen(*last), strlen(*last));
1055                         strbuf_addbuf(&sb, *ptr);
1056                         *last = strbuf_detach(&sb, NULL);
1057                         continue;
1058                 }
1059                 ALLOC_GROW(trailer_strings, nr + 1, alloc);
1060                 trailer_strings[nr] = strbuf_detach(*ptr, NULL);
1061                 last = find_separator(trailer_strings[nr], separators) >= 1
1062                         ? &trailer_strings[nr]
1063                         : NULL;
1064                 nr++;
1065         }
1066         strbuf_list_free(trailer_lines);
1067
1068         info->blank_line_before_trailer = ends_with_blank_line(str,
1069                                                                trailer_start);
1070         info->trailer_start = str + trailer_start;
1071         info->trailer_end = str + trailer_end;
1072         info->trailers = trailer_strings;
1073         info->trailer_nr = nr;
1074 }
1075
1076 void trailer_info_release(struct trailer_info *info)
1077 {
1078         int i;
1079         for (i = 0; i < info->trailer_nr; i++)
1080                 free(info->trailers[i]);
1081         free(info->trailers);
1082 }