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,
 163                       const struct process_trailer_options *opts)
 164 {
 165         struct list_head *pos;
 166         struct trailer_item *item;
 167         list_for_each(pos, head) {
 168                 item = list_entry(pos, struct trailer_item, list);
 169                 if ((!opts->trim_empty || strlen(item->value) > 0) &&
 170                     (!opts->only_trailers || item->token))
 171                         print_tok_val(outfile, item->token, item->value);
 172         }
 173 }
 174
 175 static struct trailer_item *trailer_from_arg(struct arg_item *arg_tok)
 176 {
 177         struct trailer_item *new_item = xcalloc(sizeof(*new_item), 1);
 178         new_item->token = arg_tok->token;
 179         new_item->value = arg_tok->value;
 180         arg_tok->token = arg_tok->value = NULL;
 181         free_arg_item(arg_tok);
 182         return new_item;
 183 }
 184
 185 static void add_arg_to_input_list(struct trailer_item *on_tok,
 186                                   struct arg_item *arg_tok)
 187 {
 188         int aoe = after_or_end(arg_tok->conf.where);
 189         struct trailer_item *to_add = trailer_from_arg(arg_tok);
 190         if (aoe)
 191                 list_add(&to_add->list, &on_tok->list);
 192         else
 193                 list_add_tail(&to_add->list, &on_tok->list);
 194 }
 195
 196 static int check_if_different(struct trailer_item *in_tok,
 197                               struct arg_item *arg_tok,
 198                               int check_all,
 199                               struct list_head *head)
 200 {
 201         enum trailer_where where = arg_tok->conf.where;
 202         struct list_head *next_head;
 203         do {
 204                 if (same_trailer(in_tok, arg_tok))
 205                         return 0;
 206                 /*
 207                  * if we want to add a trailer after another one,
 208                  * we have to check those before this one
 209                  */
 210                 next_head = after_or_end(where) ? in_tok->list.prev
 211                                                 : in_tok->list.next;
 212                 if (next_head == head)
 213                         break;
 214                 in_tok = list_entry(next_head, struct trailer_item, list);
 215         } while (check_all);
 216         return 1;
 217 }
 218
 219 static char *apply_command(const char *command, const char *arg)
 220 {
 221         struct strbuf cmd = STRBUF_INIT;
 222         struct strbuf buf = STRBUF_INIT;
 223         struct child_process cp = CHILD_PROCESS_INIT;
 224         const char *argv[] = {NULL, NULL};
 225         char *result;
 226
 227         strbuf_addstr(&cmd, command);
 228         if (arg)
 229                 strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 230
 231         argv[0] = cmd.buf;
 232         cp.argv = argv;
 233         cp.env = local_repo_env;
 234         cp.no_stdin = 1;
 235         cp.use_shell = 1;
 236
 237         if (capture_command(&cp, &buf, 1024)) {
 238                 error(_("running trailer command '%s' failed"), cmd.buf);
 239                 strbuf_release(&buf);
 240                 result = xstrdup("");
 241         } else {
 242                 strbuf_trim(&buf);
 243                 result = strbuf_detach(&buf, NULL);
 244         }
 245
 246         strbuf_release(&cmd);
 247         return result;
 248 }
 249
 250 static void apply_item_command(struct trailer_item *in_tok, struct arg_item *arg_tok)
 251 {
 252         if (arg_tok->conf.command) {
 253                 const char *arg;
 254                 if (arg_tok->value && arg_tok->value[0]) {
 255                         arg = arg_tok->value;
 256                 } else {
 257                         if (in_tok && in_tok->value)
 258                                 arg = xstrdup(in_tok->value);
 259                         else
 260                                 arg = xstrdup("");
 261                 }
 262                 arg_tok->value = apply_command(arg_tok->conf.command, arg);
 263                 free((char *)arg);
 264         }
 265 }
 266
 267 static void apply_arg_if_exists(struct trailer_item *in_tok,
 268                                 struct arg_item *arg_tok,
 269                                 struct trailer_item *on_tok,
 270                                 struct list_head *head)
 271 {
 272         switch (arg_tok->conf.if_exists) {
 273         case EXISTS_DO_NOTHING:
 274                 free_arg_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                 list_del(&in_tok->list);
 280                 free_trailer_item(in_tok);
 281                 break;
 282         case EXISTS_ADD:
 283                 apply_item_command(in_tok, arg_tok);
 284                 add_arg_to_input_list(on_tok, arg_tok);
 285                 break;
 286         case EXISTS_ADD_IF_DIFFERENT:
 287                 apply_item_command(in_tok, arg_tok);
 288                 if (check_if_different(in_tok, arg_tok, 1, head))
 289                         add_arg_to_input_list(on_tok, arg_tok);
 290                 else
 291                         free_arg_item(arg_tok);
 292                 break;
 293         case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 294                 apply_item_command(in_tok, arg_tok);
 295                 if (check_if_different(on_tok, arg_tok, 0, head))
 296                         add_arg_to_input_list(on_tok, arg_tok);
 297                 else
 298                         free_arg_item(arg_tok);
 299                 break;
 300         default:
 301                 BUG("trailer.c: unhandled value %d",
 302                     arg_tok->conf.if_exists);
 303         }
 304 }
 305
 306 static void apply_arg_if_missing(struct list_head *head,
 307                                  struct arg_item *arg_tok)
 308 {
 309         enum trailer_where where;
 310         struct trailer_item *to_add;
 311
 312         switch (arg_tok->conf.if_missing) {
 313         case MISSING_DO_NOTHING:
 314                 free_arg_item(arg_tok);
 315                 break;
 316         case MISSING_ADD:
 317                 where = arg_tok->conf.where;
 318                 apply_item_command(NULL, arg_tok);
 319                 to_add = trailer_from_arg(arg_tok);
 320                 if (after_or_end(where))
 321                         list_add_tail(&to_add->list, head);
 322                 else
 323                         list_add(&to_add->list, head);
 324                 break;
 325         default:
 326                 BUG("trailer.c: unhandled value %d",
 327                     arg_tok->conf.if_missing);
 328         }
 329 }
 330
 331 static int find_same_and_apply_arg(struct list_head *head,
 332                                    struct arg_item *arg_tok)
 333 {
 334         struct list_head *pos;
 335         struct trailer_item *in_tok;
 336         struct trailer_item *on_tok;
 337
 338         enum trailer_where where = arg_tok->conf.where;
 339         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 340         int backwards = after_or_end(where);
 341         struct trailer_item *start_tok;
 342
 343         if (list_empty(head))
 344                 return 0;
 345
 346         start_tok = list_entry(backwards ? head->prev : head->next,
 347                                struct trailer_item,
 348                                list);
 349
 350         list_for_each_dir(pos, head, backwards) {
 351                 in_tok = list_entry(pos, struct trailer_item, list);
 352                 if (!same_token(in_tok, arg_tok))
 353                         continue;
 354                 on_tok = middle ? in_tok : start_tok;
 355                 apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 356                 return 1;
 357         }
 358         return 0;
 359 }
 360
 361 static void process_trailers_lists(struct list_head *head,
 362                                    struct list_head *arg_head)
 363 {
 364         struct list_head *pos, *p;
 365         struct arg_item *arg_tok;
 366
 367         list_for_each_safe(pos, p, arg_head) {
 368                 int applied = 0;
 369                 arg_tok = list_entry(pos, struct arg_item, list);
 370
 371                 list_del(pos);
 372
 373                 applied = find_same_and_apply_arg(head, arg_tok);
 374
 375                 if (!applied)
 376                         apply_arg_if_missing(head, arg_tok);
 377         }
 378 }
 379
 380 int trailer_set_where(enum trailer_where *item, const char *value)
 381 {
 382         if (!value)
 383                 *item = WHERE_DEFAULT;
 384         else if (!strcasecmp("after", value))
 385                 *item = WHERE_AFTER;
 386         else if (!strcasecmp("before", value))
 387                 *item = WHERE_BEFORE;
 388         else if (!strcasecmp("end", value))
 389                 *item = WHERE_END;
 390         else if (!strcasecmp("start", value))
 391                 *item = WHERE_START;
 392         else
 393                 return -1;
 394         return 0;
 395 }
 396
 397 int trailer_set_if_exists(enum trailer_if_exists *item, const char *value)
 398 {
 399         if (!value)
 400                 *item = EXISTS_DEFAULT;
 401         else if (!strcasecmp("addIfDifferent", value))
 402                 *item = EXISTS_ADD_IF_DIFFERENT;
 403         else if (!strcasecmp("addIfDifferentNeighbor", value))
 404                 *item = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 405         else if (!strcasecmp("add", value))
 406                 *item = EXISTS_ADD;
 407         else if (!strcasecmp("replace", value))
 408                 *item = EXISTS_REPLACE;
 409         else if (!strcasecmp("doNothing", value))
 410                 *item = EXISTS_DO_NOTHING;
 411         else
 412                 return -1;
 413         return 0;
 414 }
 415
 416 int trailer_set_if_missing(enum trailer_if_missing *item, const char *value)
 417 {
 418         if (!value)
 419                 *item = MISSING_DEFAULT;
 420         else if (!strcasecmp("doNothing", value))
 421                 *item = MISSING_DO_NOTHING;
 422         else if (!strcasecmp("add", value))
 423                 *item = MISSING_ADD;
 424         else
 425                 return -1;
 426         return 0;
 427 }
 428
 429 static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 430 {
 431         *dst = *src;
 432         dst->name = xstrdup_or_null(src->name);
 433         dst->key = xstrdup_or_null(src->key);
 434         dst->command = xstrdup_or_null(src->command);
 435 }
 436
 437 static struct arg_item *get_conf_item(const char *name)
 438 {
 439         struct list_head *pos;
 440         struct arg_item *item;
 441
 442         /* Look up item with same name */
 443         list_for_each(pos, &conf_head) {
 444                 item = list_entry(pos, struct arg_item, list);
 445                 if (!strcasecmp(item->conf.name, name))
 446                         return item;
 447         }
 448
 449         /* Item does not already exists, create it */
 450         item = xcalloc(sizeof(*item), 1);
 451         duplicate_conf(&item->conf, &default_conf_info);
 452         item->conf.name = xstrdup(name);
 453
 454         list_add_tail(&item->list, &conf_head);
 455
 456         return item;
 457 }
 458
 459 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 460                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 461
 462 static struct {
 463         const char *name;
 464         enum trailer_info_type type;
 465 } trailer_config_items[] = {
 466         { "key", TRAILER_KEY },
 467         { "command", TRAILER_COMMAND },
 468         { "where", TRAILER_WHERE },
 469         { "ifexists", TRAILER_IF_EXISTS },
 470         { "ifmissing", TRAILER_IF_MISSING }
 471 };
 472
 473 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 474 {
 475         const char *trailer_item, *variable_name;
 476
 477         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 478                 return 0;
 479
 480         variable_name = strrchr(trailer_item, '.');
 481         if (!variable_name) {
 482                 if (!strcmp(trailer_item, "where")) {
 483                         if (trailer_set_where(&default_conf_info.where,
 484                                               value) < 0)
 485                                 warning(_("unknown value '%s' for key '%s'"),
 486                                         value, conf_key);
 487                 } else if (!strcmp(trailer_item, "ifexists")) {
 488                         if (trailer_set_if_exists(&default_conf_info.if_exists,
 489                                                   value) < 0)
 490                                 warning(_("unknown value '%s' for key '%s'"),
 491                                         value, conf_key);
 492                 } else if (!strcmp(trailer_item, "ifmissing")) {
 493                         if (trailer_set_if_missing(&default_conf_info.if_missing,
 494                                                    value) < 0)
 495                                 warning(_("unknown value '%s' for key '%s'"),
 496                                         value, conf_key);
 497                 } else if (!strcmp(trailer_item, "separators")) {
 498                         separators = xstrdup(value);
 499                 }
 500         }
 501         return 0;
 502 }
 503
 504 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 505 {
 506         const char *trailer_item, *variable_name;
 507         struct arg_item *item;
 508         struct conf_info *conf;
 509         char *name = NULL;
 510         enum trailer_info_type type;
 511         int i;
 512
 513         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 514                 return 0;
 515
 516         variable_name = strrchr(trailer_item, '.');
 517         if (!variable_name)
 518                 return 0;
 519
 520         variable_name++;
 521         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 522                 if (strcmp(trailer_config_items[i].name, variable_name))
 523                         continue;
 524                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 525                 type = trailer_config_items[i].type;
 526                 break;
 527         }
 528
 529         if (!name)
 530                 return 0;
 531
 532         item = get_conf_item(name);
 533         conf = &item->conf;
 534         free(name);
 535
 536         switch (type) {
 537         case TRAILER_KEY:
 538                 if (conf->key)
 539                         warning(_("more than one %s"), conf_key);
 540                 conf->key = xstrdup(value);
 541                 break;
 542         case TRAILER_COMMAND:
 543                 if (conf->command)
 544                         warning(_("more than one %s"), conf_key);
 545                 conf->command = xstrdup(value);
 546                 break;
 547         case TRAILER_WHERE:
 548                 if (trailer_set_where(&conf->where, value))
 549                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 550                 break;
 551         case TRAILER_IF_EXISTS:
 552                 if (trailer_set_if_exists(&conf->if_exists, value))
 553                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 554                 break;
 555         case TRAILER_IF_MISSING:
 556                 if (trailer_set_if_missing(&conf->if_missing, value))
 557                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 558                 break;
 559         default:
 560                 BUG("trailer.c: unhandled type %d", type);
 561         }
 562         return 0;
 563 }
 564
 565 static void ensure_configured(void)
 566 {
 567         if (configured)
 568                 return;
 569
 570         /* Default config must be setup first */
 571         default_conf_info.where = WHERE_END;
 572         default_conf_info.if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 573         default_conf_info.if_missing = MISSING_ADD;
 574         git_config(git_trailer_default_config, NULL);
 575         git_config(git_trailer_config, NULL);
 576         configured = 1;
 577 }
 578
 579 static const char *token_from_item(struct arg_item *item, char *tok)
 580 {
 581         if (item->conf.key)
 582                 return item->conf.key;
 583         if (tok)
 584                 return tok;
 585         return item->conf.name;
 586 }
 587
 588 static int token_matches_item(const char *tok, struct arg_item *item, size_t tok_len)
 589 {
 590         if (!strncasecmp(tok, item->conf.name, tok_len))
 591                 return 1;
 592         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 593 }
 594
 595 /*
 596  * If the given line is of the form
 597  * "<token><optional whitespace><separator>..." or "<separator>...", return the
 598  * location of the separator. Otherwise, return -1.  The optional whitespace
 599  * is allowed there primarily to allow things like "Bug #43" where <token> is
 600  * "Bug" and <separator> is "#".
 601  *
 602  * The separator-starts-line case (in which this function returns 0) is
 603  * distinguished from the non-well-formed-line case (in which this function
 604  * returns -1) because some callers of this function need such a distinction.
 605  */
 606 static ssize_t find_separator(const char *line, const char *separators)
 607 {
 608         int whitespace_found = 0;
 609         const char *c;
 610         for (c = line; *c; c++) {
 611                 if (strchr(separators, *c))
 612                         return c - line;
 613                 if (!whitespace_found && (isalnum(*c) || *c == '-'))
 614                         continue;
 615                 if (c != line && (*c == ' ' || *c == '\t')) {
 616                         whitespace_found = 1;
 617                         continue;
 618                 }
 619                 break;
 620         }
 621         return -1;
 622 }
 623
 624 /*
 625  * Obtain the token, value, and conf from the given trailer.
 626  *
 627  * separator_pos must not be 0, since the token cannot be an empty string.
 628  *
 629  * If separator_pos is -1, interpret the whole trailer as a token.
 630  */
 631 static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 632                          const struct conf_info **conf, const char *trailer,
 633                          ssize_t separator_pos)
 634 {
 635         struct arg_item *item;
 636         size_t tok_len;
 637         struct list_head *pos;
 638
 639         if (separator_pos != -1) {
 640                 strbuf_add(tok, trailer, separator_pos);
 641                 strbuf_trim(tok);
 642                 strbuf_addstr(val, trailer + separator_pos + 1);
 643                 strbuf_trim(val);
 644         } else {
 645                 strbuf_addstr(tok, trailer);
 646                 strbuf_trim(tok);
 647         }
 648
 649         /* Lookup if the token matches something in the config */
 650         tok_len = token_len_without_separator(tok->buf, tok->len);
 651         if (conf)
 652                 *conf = &default_conf_info;
 653         list_for_each(pos, &conf_head) {
 654                 item = list_entry(pos, struct arg_item, list);
 655                 if (token_matches_item(tok->buf, item, tok_len)) {
 656                         char *tok_buf = strbuf_detach(tok, NULL);
 657                         if (conf)
 658                                 *conf = &item->conf;
 659                         strbuf_addstr(tok, token_from_item(item, tok_buf));
 660                         free(tok_buf);
 661                         break;
 662                 }
 663         }
 664 }
 665
 666 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 667                                              char *val)
 668 {
 669         struct trailer_item *new_item = xcalloc(sizeof(*new_item), 1);
 670         new_item->token = tok;
 671         new_item->value = val;
 672         list_add_tail(&new_item->list, head);
 673         return new_item;
 674 }
 675
 676 static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 677                          const struct conf_info *conf,
 678                          const struct new_trailer_item *new_trailer_item)
 679 {
 680         struct arg_item *new_item = xcalloc(sizeof(*new_item), 1);
 681         new_item->token = tok;
 682         new_item->value = val;
 683         duplicate_conf(&new_item->conf, conf);
 684         if (new_trailer_item) {
 685                 if (new_trailer_item->where != WHERE_DEFAULT)
 686                         new_item->conf.where = new_trailer_item->where;
 687                 if (new_trailer_item->if_exists != EXISTS_DEFAULT)
 688                         new_item->conf.if_exists = new_trailer_item->if_exists;
 689                 if (new_trailer_item->if_missing != MISSING_DEFAULT)
 690                         new_item->conf.if_missing = new_trailer_item->if_missing;
 691         }
 692         list_add_tail(&new_item->list, arg_head);
 693 }
 694
 695 static void process_command_line_args(struct list_head *arg_head,
 696                                       struct list_head *new_trailer_head)
 697 {
 698         struct arg_item *item;
 699         struct strbuf tok = STRBUF_INIT;
 700         struct strbuf val = STRBUF_INIT;
 701         const struct conf_info *conf;
 702         struct list_head *pos;
 703
 704         /*
 705          * In command-line arguments, '=' is accepted (in addition to the
 706          * separators that are defined).
 707          */
 708         char *cl_separators = xstrfmt("=%s", separators);
 709
 710         /* Add an arg item for each configured trailer with a command */
 711         list_for_each(pos, &conf_head) {
 712                 item = list_entry(pos, struct arg_item, list);
 713                 if (item->conf.command)
 714                         add_arg_item(arg_head,
 715                                      xstrdup(token_from_item(item, NULL)),
 716                                      xstrdup(""),
 717                                      &item->conf, NULL);
 718         }
 719
 720         /* Add an arg item for each trailer on the command line */
 721         list_for_each(pos, new_trailer_head) {
 722                 struct new_trailer_item *tr =
 723                         list_entry(pos, struct new_trailer_item, list);
 724                 ssize_t separator_pos = find_separator(tr->text, cl_separators);
 725
 726                 if (separator_pos == 0) {
 727                         struct strbuf sb = STRBUF_INIT;
 728                         strbuf_addstr(&sb, tr->text);
 729                         strbuf_trim(&sb);
 730                         error(_("empty trailer token in trailer '%.*s'"),
 731                               (int) sb.len, sb.buf);
 732                         strbuf_release(&sb);
 733                 } else {
 734                         parse_trailer(&tok, &val, &conf, tr->text,
 735                                       separator_pos);
 736                         add_arg_item(arg_head,
 737                                      strbuf_detach(&tok, NULL),
 738                                      strbuf_detach(&val, NULL),
 739                                      conf, tr);
 740                 }
 741         }
 742
 743         free(cl_separators);
 744 }
 745
 746 static void read_input_file(struct strbuf *sb, const char *file)
 747 {
 748         if (file) {
 749                 if (strbuf_read_file(sb, file, 0) < 0)
 750                         die_errno(_("could not read input file '%s'"), file);
 751         } else {
 752                 if (strbuf_read(sb, fileno(stdin), 0) < 0)
 753                         die_errno(_("could not read from stdin"));
 754         }
 755 }
 756
 757 static const char *next_line(const char *str)
 758 {
 759         const char *nl = strchrnul(str, '\n');
 760         return nl + !!*nl;
 761 }
 762
 763 /*
 764  * Return the position of the start of the last line. If len is 0, return -1.
 765  */
 766 static ssize_t last_line(const char *buf, size_t len)
 767 {
 768         ssize_t i;
 769         if (len == 0)
 770                 return -1;
 771         if (len == 1)
 772                 return 0;
 773         /*
 774          * Skip the last character (in addition to the null terminator),
 775          * because if the last character is a newline, it is considered as part
 776          * of the last line anyway.
 777          */
 778         i = len - 2;
 779
 780         for (; i >= 0; i--) {
 781                 if (buf[i] == '\n')
 782                         return i + 1;
 783         }
 784         return 0;
 785 }
 786
 787 /*
 788  * Return the position of the start of the patch or the length of str if there
 789  * is no patch in the message.
 790  */
 791 static size_t find_patch_start(const char *str)
 792 {
 793         const char *s;
 794
 795         for (s = str; *s; s = next_line(s)) {
 796                 const char *v;
 797
 798                 if (skip_prefix(s, "---", &v) && isspace(*v))
 799                         return s - str;
 800         }
 801
 802         return s - str;
 803 }
 804
 805 /*
 806  * Return the position of the first trailer line or len if there are no
 807  * trailers.
 808  */
 809 static size_t find_trailer_start(const char *buf, size_t len)
 810 {
 811         const char *s;
 812         ssize_t end_of_title, l;
 813         int only_spaces = 1;
 814         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 815         /*
 816          * Number of possible continuation lines encountered. This will be
 817          * reset to 0 if we encounter a trailer (since those lines are to be
 818          * considered continuations of that trailer), and added to
 819          * non_trailer_lines if we encounter a non-trailer (since those lines
 820          * are to be considered non-trailers).
 821          */
 822         int possible_continuation_lines = 0;
 823
 824         /* The first paragraph is the title and cannot be trailers */
 825         for (s = buf; s < buf + len; s = next_line(s)) {
 826                 if (s[0] == comment_line_char)
 827                         continue;
 828                 if (is_blank_line(s))
 829                         break;
 830         }
 831         end_of_title = s - buf;
 832
 833         /*
 834          * Get the start of the trailers by looking starting from the end for a
 835          * blank line before a set of non-blank lines that (i) are all
 836          * trailers, or (ii) contains at least one Git-generated trailer and
 837          * consists of at least 25% trailers.
 838          */
 839         for (l = last_line(buf, len);
 840              l >= end_of_title;
 841              l = last_line(buf, l)) {
 842                 const char *bol = buf + l;
 843                 const char **p;
 844                 ssize_t separator_pos;
 845
 846                 if (bol[0] == comment_line_char) {
 847                         non_trailer_lines += possible_continuation_lines;
 848                         possible_continuation_lines = 0;
 849                         continue;
 850                 }
 851                 if (is_blank_line(bol)) {
 852                         if (only_spaces)
 853                                 continue;
 854                         non_trailer_lines += possible_continuation_lines;
 855                         if (recognized_prefix &&
 856                             trailer_lines * 3 >= non_trailer_lines)
 857                                 return next_line(bol) - buf;
 858                         else if (trailer_lines && !non_trailer_lines)
 859                                 return next_line(bol) - buf;
 860                         return len;
 861                 }
 862                 only_spaces = 0;
 863
 864                 for (p = git_generated_prefixes; *p; p++) {
 865                         if (starts_with(bol, *p)) {
 866                                 trailer_lines++;
 867                                 possible_continuation_lines = 0;
 868                                 recognized_prefix = 1;
 869                                 goto continue_outer_loop;
 870                         }
 871                 }
 872
 873                 separator_pos = find_separator(bol, separators);
 874                 if (separator_pos >= 1 && !isspace(bol[0])) {
 875                         struct list_head *pos;
 876
 877                         trailer_lines++;
 878                         possible_continuation_lines = 0;
 879                         if (recognized_prefix)
 880                                 continue;
 881                         list_for_each(pos, &conf_head) {
 882                                 struct arg_item *item;
 883                                 item = list_entry(pos, struct arg_item, list);
 884                                 if (token_matches_item(bol, item,
 885                                                        separator_pos)) {
 886                                         recognized_prefix = 1;
 887                                         break;
 888                                 }
 889                         }
 890                 } else if (isspace(bol[0]))
 891                         possible_continuation_lines++;
 892                 else {
 893                         non_trailer_lines++;
 894                         non_trailer_lines += possible_continuation_lines;
 895                         possible_continuation_lines = 0;
 896                 }
 897 continue_outer_loop:
 898                 ;
 899         }
 900
 901         return len;
 902 }
 903
 904 /* Return the position of the end of the trailers. */
 905 static size_t find_trailer_end(const char *buf, size_t len)
 906 {
 907         return len - ignore_non_trailer(buf, len);
 908 }
 909
 910 static int ends_with_blank_line(const char *buf, size_t len)
 911 {
 912         ssize_t ll = last_line(buf, len);
 913         if (ll < 0)
 914                 return 0;
 915         return is_blank_line(buf + ll);
 916 }
 917
 918 static void unfold_value(struct strbuf *val)
 919 {
 920         struct strbuf out = STRBUF_INIT;
 921         size_t i;
 922
 923         strbuf_grow(&out, val->len);
 924         i = 0;
 925         while (i < val->len) {
 926                 char c = val->buf[i++];
 927                 if (c == '\n') {
 928                         /* Collapse continuation down to a single space. */
 929                         while (i < val->len && isspace(val->buf[i]))
 930                                 i++;
 931                         strbuf_addch(&out, ' ');
 932                 } else {
 933                         strbuf_addch(&out, c);
 934                 }
 935         }
 936
 937         /* Empty lines may have left us with whitespace cruft at the edges */
 938         strbuf_trim(&out);
 939
 940         /* output goes back to val as if we modified it in-place */
 941         strbuf_swap(&out, val);
 942         strbuf_release(&out);
 943 }
 944
 945 static size_t process_input_file(FILE *outfile,
 946                                  const char *str,
 947                                  struct list_head *head,
 948                                  const struct process_trailer_options *opts)
 949 {
 950         struct trailer_info info;
 951         struct strbuf tok = STRBUF_INIT;
 952         struct strbuf val = STRBUF_INIT;
 953         size_t i;
 954
 955         trailer_info_get(&info, str, opts);
 956
 957         /* Print lines before the trailers as is */
 958         if (!opts->only_trailers)
 959                 fwrite(str, 1, info.trailer_start - str, outfile);
 960
 961         if (!opts->only_trailers && !info.blank_line_before_trailer)
 962                 fprintf(outfile, "\n");
 963
 964         for (i = 0; i < info.trailer_nr; i++) {
 965                 int separator_pos;
 966                 char *trailer = info.trailers[i];
 967                 if (trailer[0] == comment_line_char)
 968                         continue;
 969                 separator_pos = find_separator(trailer, separators);
 970                 if (separator_pos >= 1) {
 971                         parse_trailer(&tok, &val, NULL, trailer,
 972                                       separator_pos);
 973                         if (opts->unfold)
 974                                 unfold_value(&val);
 975                         add_trailer_item(head,
 976                                          strbuf_detach(&tok, NULL),
 977                                          strbuf_detach(&val, NULL));
 978                 } else if (!opts->only_trailers) {
 979                         strbuf_addstr(&val, trailer);
 980                         strbuf_strip_suffix(&val, "\n");
 981                         add_trailer_item(head,
 982                                          NULL,
 983                                          strbuf_detach(&val, NULL));
 984                 }
 985         }
 986
 987         trailer_info_release(&info);
 988
 989         return info.trailer_end - str;
 990 }
 991
 992 static void free_all(struct list_head *head)
 993 {
 994         struct list_head *pos, *p;
 995         list_for_each_safe(pos, p, head) {
 996                 list_del(pos);
 997                 free_trailer_item(list_entry(pos, struct trailer_item, list));
 998         }
 999 }
1000
1001 static struct tempfile *trailers_tempfile;
1002
1003 static FILE *create_in_place_tempfile(const char *file)
1004 {
1005         struct stat st;
1006         struct strbuf filename_template = STRBUF_INIT;
1007         const char *tail;
1008         FILE *outfile;
1009
1010         if (stat(file, &st))
1011                 die_errno(_("could not stat %s"), file);
1012         if (!S_ISREG(st.st_mode))
1013                 die(_("file %s is not a regular file"), file);
1014         if (!(st.st_mode & S_IWUSR))
1015                 die(_("file %s is not writable by user"), file);
1016
1017         /* Create temporary file in the same directory as the original */
1018         tail = strrchr(file, '/');
1019         if (tail != NULL)
1020                 strbuf_add(&filename_template, file, tail - file + 1);
1021         strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
1022
1023         trailers_tempfile = xmks_tempfile_m(filename_template.buf, st.st_mode);
1024         strbuf_release(&filename_template);
1025         outfile = fdopen_tempfile(trailers_tempfile, "w");
1026         if (!outfile)
1027                 die_errno(_("could not open temporary file"));
1028
1029         return outfile;
1030 }
1031
1032 void process_trailers(const char *file,
1033                       const struct process_trailer_options *opts,
1034                       struct list_head *new_trailer_head)
1035 {
1036         LIST_HEAD(head);
1037         struct strbuf sb = STRBUF_INIT;
1038         size_t trailer_end;
1039         FILE *outfile = stdout;
1040
1041         ensure_configured();
1042
1043         read_input_file(&sb, file);
1044
1045         if (opts->in_place)
1046                 outfile = create_in_place_tempfile(file);
1047
1048         /* Print the lines before the trailers */
1049         trailer_end = process_input_file(outfile, sb.buf, &head, opts);
1050
1051         if (!opts->only_input) {
1052                 LIST_HEAD(arg_head);
1053                 process_command_line_args(&arg_head, new_trailer_head);
1054                 process_trailers_lists(&head, &arg_head);
1055         }
1056
1057         print_all(outfile, &head, opts);
1058
1059         free_all(&head);
1060
1061         /* Print the lines after the trailers as is */
1062         if (!opts->only_trailers)
1063                 fwrite(sb.buf + trailer_end, 1, sb.len - trailer_end, outfile);
1064
1065         if (opts->in_place)
1066                 if (rename_tempfile(&trailers_tempfile, file))
1067                         die_errno(_("could not rename temporary file to %s"), file);
1068
1069         strbuf_release(&sb);
1070 }
1071
1072 void trailer_info_get(struct trailer_info *info, const char *str,
1073                       const struct process_trailer_options *opts)
1074 {
1075         int patch_start, trailer_end, trailer_start;
1076         struct strbuf **trailer_lines, **ptr;
1077         char **trailer_strings = NULL;
1078         size_t nr = 0, alloc = 0;
1079         char **last = NULL;
1080
1081         ensure_configured();
1082
1083         if (opts->no_divider)
1084                 patch_start = strlen(str);
1085         else
1086                 patch_start = find_patch_start(str);
1087
1088         trailer_end = find_trailer_end(str, patch_start);
1089         trailer_start = find_trailer_start(str, trailer_end);
1090
1091         trailer_lines = strbuf_split_buf(str + trailer_start,
1092                                          trailer_end - trailer_start,
1093                                          '\n',
1094                                          0);
1095         for (ptr = trailer_lines; *ptr; ptr++) {
1096                 if (last && isspace((*ptr)->buf[0])) {
1097                         struct strbuf sb = STRBUF_INIT;
1098                         strbuf_attach(&sb, *last, strlen(*last), strlen(*last));
1099                         strbuf_addbuf(&sb, *ptr);
1100                         *last = strbuf_detach(&sb, NULL);
1101                         continue;
1102                 }
1103                 ALLOC_GROW(trailer_strings, nr + 1, alloc);
1104                 trailer_strings[nr] = strbuf_detach(*ptr, NULL);
1105                 last = find_separator(trailer_strings[nr], separators) >= 1
1106                         ? &trailer_strings[nr]
1107                         : NULL;
1108                 nr++;
1109         }
1110         strbuf_list_free(trailer_lines);
1111
1112         info->blank_line_before_trailer = ends_with_blank_line(str,
1113                                                                trailer_start);
1114         info->trailer_start = str + trailer_start;
1115         info->trailer_end = str + trailer_end;
1116         info->trailers = trailer_strings;
1117         info->trailer_nr = nr;
1118 }
1119
1120 void trailer_info_release(struct trailer_info *info)
1121 {
1122         size_t i;
1123         for (i = 0; i < info->trailer_nr; i++)
1124                 free(info->trailers[i]);
1125         free(info->trailers);
1126 }
1127
1128 static void format_trailer_info(struct strbuf *out,
1129                                 const struct trailer_info *info,
1130                                 const struct process_trailer_options *opts)
1131 {
1132         size_t origlen = out->len;
1133         size_t i;
1134
1135         /* If we want the whole block untouched, we can take the fast path. */
1136         if (!opts->only_trailers && !opts->unfold && !opts->filter && !opts->separator) {
1137                 strbuf_add(out, info->trailer_start,
1138                            info->trailer_end - info->trailer_start);
1139                 return;
1140         }
1141
1142         for (i = 0; i < info->trailer_nr; i++) {
1143                 char *trailer = info->trailers[i];
1144                 ssize_t separator_pos = find_separator(trailer, separators);
1145
1146                 if (separator_pos >= 1) {
1147                         struct strbuf tok = STRBUF_INIT;
1148                         struct strbuf val = STRBUF_INIT;
1149
1150                         parse_trailer(&tok, &val, NULL, trailer, separator_pos);
1151                         if (!opts->filter || opts->filter(&tok, opts->filter_data)) {
1152                                 if (opts->unfold)
1153                                         unfold_value(&val);
1154
1155                                 if (opts->separator && out->len != origlen)
1156                                         strbuf_addbuf(out, opts->separator);
1157                                 if (!opts->value_only)
1158                                         strbuf_addf(out, "%s: ", tok.buf);
1159                                 strbuf_addbuf(out, &val);
1160                                 if (!opts->separator)
1161                                         strbuf_addch(out, '\n');
1162                         }
1163                         strbuf_release(&tok);
1164                         strbuf_release(&val);
1165
1166                 } else if (!opts->only_trailers) {
1167                         if (opts->separator && out->len != origlen) {
1168                                 strbuf_addbuf(out, opts->separator);
1169                         }
1170                         strbuf_addstr(out, trailer);
1171                         if (opts->separator) {
1172                                 strbuf_rtrim(out);
1173                         }
1174                 }
1175         }
1176
1177 }
1178
1179 void format_trailers_from_commit(struct strbuf *out, const char *msg,
1180                                  const struct process_trailer_options *opts)
1181 {
1182         struct trailer_info info;
1183
1184         trailer_info_get(&info, msg, opts);
1185         format_trailer_info(out, &info, opts);
1186         trailer_info_release(&info);
1187 }