trailer.c

   1 #include "git-compat-util.h"
   2 #include "config.h"
   3 #include "environment.h"
   4 #include "gettext.h"
   5 #include "string-list.h"
   6 #include "run-command.h"
   7 #include "commit.h"
   8 #include "trailer.h"
   9 #include "list.h"
  10 /*
  11  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  12  */
  13
  14 struct conf_info {
  15         char *name;
  16         char *key;
  17         char *command;
  18         char *cmd;
  19         enum trailer_where where;
  20         enum trailer_if_exists if_exists;
  21         enum trailer_if_missing if_missing;
  22 };
  23
  24 static struct conf_info default_conf_info;
  25
  26 struct trailer_item {
  27         struct list_head list;
  28         /*
  29          * If this is not a trailer line, the line is stored in value
  30          * (excluding the terminating newline) and token is NULL.
  31          */
  32         char *token;
  33         char *value;
  34 };
  35
  36 struct arg_item {
  37         struct list_head list;
  38         char *token;
  39         char *value;
  40         struct conf_info conf;
  41 };
  42
  43 static LIST_HEAD(conf_head);
  44
  45 static char *separators = ":";
  46
  47 static int configured;
  48
  49 #define TRAILER_ARG_STRING "$ARG"
  50
  51 static const char *git_generated_prefixes[] = {
  52         "Signed-off-by: ",
  53         "(cherry picked from commit ",
  54         NULL
  55 };
  56
  57 /* Iterate over the elements of the list. */
  58 #define list_for_each_dir(pos, head, is_reverse) \
  59         for (pos = is_reverse ? (head)->prev : (head)->next; \
  60                 pos != (head); \
  61                 pos = is_reverse ? pos->prev : pos->next)
  62
  63 static int after_or_end(enum trailer_where where)
  64 {
  65         return (where == WHERE_AFTER) || (where == WHERE_END);
  66 }
  67
  68 /*
  69  * Return the length of the string not including any final
  70  * punctuation. E.g., the input "Signed-off-by:" would return
  71  * 13, stripping the trailing punctuation but retaining
  72  * internal punctuation.
  73  */
  74 static size_t token_len_without_separator(const char *token, size_t len)
  75 {
  76         while (len > 0 && !isalnum(token[len - 1]))
  77                 len--;
  78         return len;
  79 }
  80
  81 static int same_token(struct trailer_item *a, struct arg_item *b)
  82 {
  83         size_t a_len, b_len, min_len;
  84
  85         if (!a->token)
  86                 return 0;
  87
  88         a_len = token_len_without_separator(a->token, strlen(a->token));
  89         b_len = token_len_without_separator(b->token, strlen(b->token));
  90         min_len = (a_len > b_len) ? b_len : a_len;
  91
  92         return !strncasecmp(a->token, b->token, min_len);
  93 }
  94
  95 static int same_value(struct trailer_item *a, struct arg_item *b)
  96 {
  97         return !strcasecmp(a->value, b->value);
  98 }
  99
 100 static int same_trailer(struct trailer_item *a, struct arg_item *b)
 101 {
 102         return same_token(a, b) && same_value(a, b);
 103 }
 104
 105 static inline int is_blank_line(const char *str)
 106 {
 107         const char *s = str;
 108         while (*s && *s != '\n' && isspace(*s))
 109                 s++;
 110         return !*s || *s == '\n';
 111 }
 112
 113 static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
 114 {
 115         const char *ptr = strstr(sb->buf, a);
 116         if (ptr)
 117                 strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
 118 }
 119
 120 static void free_trailer_item(struct trailer_item *item)
 121 {
 122         free(item->token);
 123         free(item->value);
 124         free(item);
 125 }
 126
 127 static void free_arg_item(struct arg_item *item)
 128 {
 129         free(item->conf.name);
 130         free(item->conf.key);
 131         free(item->conf.command);
 132         free(item->conf.cmd);
 133         free(item->token);
 134         free(item->value);
 135         free(item);
 136 }
 137
 138 static char last_non_space_char(const char *s)
 139 {
 140         int i;
 141         for (i = strlen(s) - 1; i >= 0; i--)
 142                 if (!isspace(s[i]))
 143                         return s[i];
 144         return '\0';
 145 }
 146
 147 static void print_tok_val(FILE *outfile, const char *tok, const char *val)
 148 {
 149         char c;
 150
 151         if (!tok) {
 152                 fprintf(outfile, "%s\n", val);
 153                 return;
 154         }
 155
 156         c = last_non_space_char(tok);
 157         if (!c)
 158                 return;
 159         if (strchr(separators, c))
 160                 fprintf(outfile, "%s%s\n", tok, val);
 161         else
 162                 fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 163 }
 164
 165 void format_trailers(const struct process_trailer_options *opts,
 166                      struct list_head *trailers, FILE *outfile)
 167 {
 168         struct list_head *pos;
 169         struct trailer_item *item;
 170         list_for_each(pos, trailers) {
 171                 item = list_entry(pos, struct trailer_item, list);
 172                 if ((!opts->trim_empty || strlen(item->value) > 0) &&
 173                     (!opts->only_trailers || item->token))
 174                         print_tok_val(outfile, item->token, item->value);
 175         }
 176 }
 177
 178 static struct trailer_item *trailer_from_arg(struct arg_item *arg_tok)
 179 {
 180         struct trailer_item *new_item = xcalloc(1, sizeof(*new_item));
 181         new_item->token = arg_tok->token;
 182         new_item->value = arg_tok->value;
 183         arg_tok->token = arg_tok->value = NULL;
 184         free_arg_item(arg_tok);
 185         return new_item;
 186 }
 187
 188 static void add_arg_to_input_list(struct trailer_item *on_tok,
 189                                   struct arg_item *arg_tok)
 190 {
 191         int aoe = after_or_end(arg_tok->conf.where);
 192         struct trailer_item *to_add = trailer_from_arg(arg_tok);
 193         if (aoe)
 194                 list_add(&to_add->list, &on_tok->list);
 195         else
 196                 list_add_tail(&to_add->list, &on_tok->list);
 197 }
 198
 199 static int check_if_different(struct trailer_item *in_tok,
 200                               struct arg_item *arg_tok,
 201                               int check_all,
 202                               struct list_head *head)
 203 {
 204         enum trailer_where where = arg_tok->conf.where;
 205         struct list_head *next_head;
 206         do {
 207                 if (same_trailer(in_tok, arg_tok))
 208                         return 0;
 209                 /*
 210                  * if we want to add a trailer after another one,
 211                  * we have to check those before this one
 212                  */
 213                 next_head = after_or_end(where) ? in_tok->list.prev
 214                                                 : in_tok->list.next;
 215                 if (next_head == head)
 216                         break;
 217                 in_tok = list_entry(next_head, struct trailer_item, list);
 218         } while (check_all);
 219         return 1;
 220 }
 221
 222 static char *apply_command(struct conf_info *conf, const char *arg)
 223 {
 224         struct strbuf cmd = STRBUF_INIT;
 225         struct strbuf buf = STRBUF_INIT;
 226         struct child_process cp = CHILD_PROCESS_INIT;
 227         char *result;
 228
 229         if (conf->cmd) {
 230                 strbuf_addstr(&cmd, conf->cmd);
 231                 strvec_push(&cp.args, cmd.buf);
 232                 if (arg)
 233                         strvec_push(&cp.args, arg);
 234         } else if (conf->command) {
 235                 strbuf_addstr(&cmd, conf->command);
 236                 if (arg)
 237                         strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 238                 strvec_push(&cp.args, cmd.buf);
 239         }
 240         strvec_pushv(&cp.env, (const char **)local_repo_env);
 241         cp.no_stdin = 1;
 242         cp.use_shell = 1;
 243
 244         if (capture_command(&cp, &buf, 1024)) {
 245                 error(_("running trailer command '%s' failed"), cmd.buf);
 246                 strbuf_release(&buf);
 247                 result = xstrdup("");
 248         } else {
 249                 strbuf_trim(&buf);
 250                 result = strbuf_detach(&buf, NULL);
 251         }
 252
 253         strbuf_release(&cmd);
 254         return result;
 255 }
 256
 257 static void apply_item_command(struct trailer_item *in_tok, struct arg_item *arg_tok)
 258 {
 259         if (arg_tok->conf.command || arg_tok->conf.cmd) {
 260                 const char *arg;
 261                 if (arg_tok->value && arg_tok->value[0]) {
 262                         arg = arg_tok->value;
 263                 } else {
 264                         if (in_tok && in_tok->value)
 265                                 arg = xstrdup(in_tok->value);
 266                         else
 267                                 arg = xstrdup("");
 268                 }
 269                 arg_tok->value = apply_command(&arg_tok->conf, arg);
 270                 free((char *)arg);
 271         }
 272 }
 273
 274 static void apply_arg_if_exists(struct trailer_item *in_tok,
 275                                 struct arg_item *arg_tok,
 276                                 struct trailer_item *on_tok,
 277                                 struct list_head *head)
 278 {
 279         switch (arg_tok->conf.if_exists) {
 280         case EXISTS_DO_NOTHING:
 281                 free_arg_item(arg_tok);
 282                 break;
 283         case EXISTS_REPLACE:
 284                 apply_item_command(in_tok, arg_tok);
 285                 add_arg_to_input_list(on_tok, arg_tok);
 286                 list_del(&in_tok->list);
 287                 free_trailer_item(in_tok);
 288                 break;
 289         case EXISTS_ADD:
 290                 apply_item_command(in_tok, arg_tok);
 291                 add_arg_to_input_list(on_tok, arg_tok);
 292                 break;
 293         case EXISTS_ADD_IF_DIFFERENT:
 294                 apply_item_command(in_tok, arg_tok);
 295                 if (check_if_different(in_tok, arg_tok, 1, head))
 296                         add_arg_to_input_list(on_tok, arg_tok);
 297                 else
 298                         free_arg_item(arg_tok);
 299                 break;
 300         case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 301                 apply_item_command(in_tok, arg_tok);
 302                 if (check_if_different(on_tok, arg_tok, 0, head))
 303                         add_arg_to_input_list(on_tok, arg_tok);
 304                 else
 305                         free_arg_item(arg_tok);
 306                 break;
 307         default:
 308                 BUG("trailer.c: unhandled value %d",
 309                     arg_tok->conf.if_exists);
 310         }
 311 }
 312
 313 static void apply_arg_if_missing(struct list_head *head,
 314                                  struct arg_item *arg_tok)
 315 {
 316         enum trailer_where where;
 317         struct trailer_item *to_add;
 318
 319         switch (arg_tok->conf.if_missing) {
 320         case MISSING_DO_NOTHING:
 321                 free_arg_item(arg_tok);
 322                 break;
 323         case MISSING_ADD:
 324                 where = arg_tok->conf.where;
 325                 apply_item_command(NULL, arg_tok);
 326                 to_add = trailer_from_arg(arg_tok);
 327                 if (after_or_end(where))
 328                         list_add_tail(&to_add->list, head);
 329                 else
 330                         list_add(&to_add->list, head);
 331                 break;
 332         default:
 333                 BUG("trailer.c: unhandled value %d",
 334                     arg_tok->conf.if_missing);
 335         }
 336 }
 337
 338 static int find_same_and_apply_arg(struct list_head *head,
 339                                    struct arg_item *arg_tok)
 340 {
 341         struct list_head *pos;
 342         struct trailer_item *in_tok;
 343         struct trailer_item *on_tok;
 344
 345         enum trailer_where where = arg_tok->conf.where;
 346         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 347         int backwards = after_or_end(where);
 348         struct trailer_item *start_tok;
 349
 350         if (list_empty(head))
 351                 return 0;
 352
 353         start_tok = list_entry(backwards ? head->prev : head->next,
 354                                struct trailer_item,
 355                                list);
 356
 357         list_for_each_dir(pos, head, backwards) {
 358                 in_tok = list_entry(pos, struct trailer_item, list);
 359                 if (!same_token(in_tok, arg_tok))
 360                         continue;
 361                 on_tok = middle ? in_tok : start_tok;
 362                 apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 363                 return 1;
 364         }
 365         return 0;
 366 }
 367
 368 void process_trailers_lists(struct list_head *head,
 369                             struct list_head *arg_head)
 370 {
 371         struct list_head *pos, *p;
 372         struct arg_item *arg_tok;
 373
 374         list_for_each_safe(pos, p, arg_head) {
 375                 int applied = 0;
 376                 arg_tok = list_entry(pos, struct arg_item, list);
 377
 378                 list_del(pos);
 379
 380                 applied = find_same_and_apply_arg(head, arg_tok);
 381
 382                 if (!applied)
 383                         apply_arg_if_missing(head, arg_tok);
 384         }
 385 }
 386
 387 int trailer_set_where(enum trailer_where *item, const char *value)
 388 {
 389         if (!value)
 390                 *item = WHERE_DEFAULT;
 391         else if (!strcasecmp("after", value))
 392                 *item = WHERE_AFTER;
 393         else if (!strcasecmp("before", value))
 394                 *item = WHERE_BEFORE;
 395         else if (!strcasecmp("end", value))
 396                 *item = WHERE_END;
 397         else if (!strcasecmp("start", value))
 398                 *item = WHERE_START;
 399         else
 400                 return -1;
 401         return 0;
 402 }
 403
 404 int trailer_set_if_exists(enum trailer_if_exists *item, const char *value)
 405 {
 406         if (!value)
 407                 *item = EXISTS_DEFAULT;
 408         else if (!strcasecmp("addIfDifferent", value))
 409                 *item = EXISTS_ADD_IF_DIFFERENT;
 410         else if (!strcasecmp("addIfDifferentNeighbor", value))
 411                 *item = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 412         else if (!strcasecmp("add", value))
 413                 *item = EXISTS_ADD;
 414         else if (!strcasecmp("replace", value))
 415                 *item = EXISTS_REPLACE;
 416         else if (!strcasecmp("doNothing", value))
 417                 *item = EXISTS_DO_NOTHING;
 418         else
 419                 return -1;
 420         return 0;
 421 }
 422
 423 int trailer_set_if_missing(enum trailer_if_missing *item, const char *value)
 424 {
 425         if (!value)
 426                 *item = MISSING_DEFAULT;
 427         else if (!strcasecmp("doNothing", value))
 428                 *item = MISSING_DO_NOTHING;
 429         else if (!strcasecmp("add", value))
 430                 *item = MISSING_ADD;
 431         else
 432                 return -1;
 433         return 0;
 434 }
 435
 436 static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 437 {
 438         *dst = *src;
 439         dst->name = xstrdup_or_null(src->name);
 440         dst->key = xstrdup_or_null(src->key);
 441         dst->command = xstrdup_or_null(src->command);
 442         dst->cmd = xstrdup_or_null(src->cmd);
 443 }
 444
 445 static struct arg_item *get_conf_item(const char *name)
 446 {
 447         struct list_head *pos;
 448         struct arg_item *item;
 449
 450         /* Look up item with same name */
 451         list_for_each(pos, &conf_head) {
 452                 item = list_entry(pos, struct arg_item, list);
 453                 if (!strcasecmp(item->conf.name, name))
 454                         return item;
 455         }
 456
 457         /* Item does not already exists, create it */
 458         CALLOC_ARRAY(item, 1);
 459         duplicate_conf(&item->conf, &default_conf_info);
 460         item->conf.name = xstrdup(name);
 461
 462         list_add_tail(&item->list, &conf_head);
 463
 464         return item;
 465 }
 466
 467 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_CMD,
 468                         TRAILER_WHERE, TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 469
 470 static struct {
 471         const char *name;
 472         enum trailer_info_type type;
 473 } trailer_config_items[] = {
 474         { "key", TRAILER_KEY },
 475         { "command", TRAILER_COMMAND },
 476         { "cmd", TRAILER_CMD },
 477         { "where", TRAILER_WHERE },
 478         { "ifexists", TRAILER_IF_EXISTS },
 479         { "ifmissing", TRAILER_IF_MISSING }
 480 };
 481
 482 static int git_trailer_default_config(const char *conf_key, const char *value,
 483                                       const struct config_context *ctx UNUSED,
 484                                       void *cb UNUSED)
 485 {
 486         const char *trailer_item, *variable_name;
 487
 488         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 489                 return 0;
 490
 491         variable_name = strrchr(trailer_item, '.');
 492         if (!variable_name) {
 493                 if (!strcmp(trailer_item, "where")) {
 494                         if (trailer_set_where(&default_conf_info.where,
 495                                               value) < 0)
 496                                 warning(_("unknown value '%s' for key '%s'"),
 497                                         value, conf_key);
 498                 } else if (!strcmp(trailer_item, "ifexists")) {
 499                         if (trailer_set_if_exists(&default_conf_info.if_exists,
 500                                                   value) < 0)
 501                                 warning(_("unknown value '%s' for key '%s'"),
 502                                         value, conf_key);
 503                 } else if (!strcmp(trailer_item, "ifmissing")) {
 504                         if (trailer_set_if_missing(&default_conf_info.if_missing,
 505                                                    value) < 0)
 506                                 warning(_("unknown value '%s' for key '%s'"),
 507                                         value, conf_key);
 508                 } else if (!strcmp(trailer_item, "separators")) {
 509                         if (!value)
 510                                 return config_error_nonbool(conf_key);
 511                         separators = xstrdup(value);
 512                 }
 513         }
 514         return 0;
 515 }
 516
 517 static int git_trailer_config(const char *conf_key, const char *value,
 518                               const struct config_context *ctx UNUSED,
 519                               void *cb UNUSED)
 520 {
 521         const char *trailer_item, *variable_name;
 522         struct arg_item *item;
 523         struct conf_info *conf;
 524         char *name = NULL;
 525         enum trailer_info_type type;
 526         int i;
 527
 528         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 529                 return 0;
 530
 531         variable_name = strrchr(trailer_item, '.');
 532         if (!variable_name)
 533                 return 0;
 534
 535         variable_name++;
 536         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 537                 if (strcmp(trailer_config_items[i].name, variable_name))
 538                         continue;
 539                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 540                 type = trailer_config_items[i].type;
 541                 break;
 542         }
 543
 544         if (!name)
 545                 return 0;
 546
 547         item = get_conf_item(name);
 548         conf = &item->conf;
 549         free(name);
 550
 551         switch (type) {
 552         case TRAILER_KEY:
 553                 if (conf->key)
 554                         warning(_("more than one %s"), conf_key);
 555                 if (!value)
 556                         return config_error_nonbool(conf_key);
 557                 conf->key = xstrdup(value);
 558                 break;
 559         case TRAILER_COMMAND:
 560                 if (conf->command)
 561                         warning(_("more than one %s"), conf_key);
 562                 if (!value)
 563                         return config_error_nonbool(conf_key);
 564                 conf->command = xstrdup(value);
 565                 break;
 566         case TRAILER_CMD:
 567                 if (conf->cmd)
 568                         warning(_("more than one %s"), conf_key);
 569                 if (!value)
 570                         return config_error_nonbool(conf_key);
 571                 conf->cmd = xstrdup(value);
 572                 break;
 573         case TRAILER_WHERE:
 574                 if (trailer_set_where(&conf->where, value))
 575                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 576                 break;
 577         case TRAILER_IF_EXISTS:
 578                 if (trailer_set_if_exists(&conf->if_exists, value))
 579                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 580                 break;
 581         case TRAILER_IF_MISSING:
 582                 if (trailer_set_if_missing(&conf->if_missing, value))
 583                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 584                 break;
 585         default:
 586                 BUG("trailer.c: unhandled type %d", type);
 587         }
 588         return 0;
 589 }
 590
 591 void trailer_config_init(void)
 592 {
 593         if (configured)
 594                 return;
 595
 596         /* Default config must be setup first */
 597         default_conf_info.where = WHERE_END;
 598         default_conf_info.if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 599         default_conf_info.if_missing = MISSING_ADD;
 600         git_config(git_trailer_default_config, NULL);
 601         git_config(git_trailer_config, NULL);
 602         configured = 1;
 603 }
 604
 605 static const char *token_from_item(struct arg_item *item, char *tok)
 606 {
 607         if (item->conf.key)
 608                 return item->conf.key;
 609         if (tok)
 610                 return tok;
 611         return item->conf.name;
 612 }
 613
 614 static int token_matches_item(const char *tok, struct arg_item *item, size_t tok_len)
 615 {
 616         if (!strncasecmp(tok, item->conf.name, tok_len))
 617                 return 1;
 618         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 619 }
 620
 621 /*
 622  * If the given line is of the form
 623  * "<token><optional whitespace><separator>..." or "<separator>...", return the
 624  * location of the separator. Otherwise, return -1.  The optional whitespace
 625  * is allowed there primarily to allow things like "Bug #43" where <token> is
 626  * "Bug" and <separator> is "#".
 627  *
 628  * The separator-starts-line case (in which this function returns 0) is
 629  * distinguished from the non-well-formed-line case (in which this function
 630  * returns -1) because some callers of this function need such a distinction.
 631  */
 632 static ssize_t find_separator(const char *line, const char *separators)
 633 {
 634         int whitespace_found = 0;
 635         const char *c;
 636         for (c = line; *c; c++) {
 637                 if (strchr(separators, *c))
 638                         return c - line;
 639                 if (!whitespace_found && (isalnum(*c) || *c == '-'))
 640                         continue;
 641                 if (c != line && (*c == ' ' || *c == '\t')) {
 642                         whitespace_found = 1;
 643                         continue;
 644                 }
 645                 break;
 646         }
 647         return -1;
 648 }
 649
 650 /*
 651  * Obtain the token, value, and conf from the given trailer.
 652  *
 653  * separator_pos must not be 0, since the token cannot be an empty string.
 654  *
 655  * If separator_pos is -1, interpret the whole trailer as a token.
 656  */
 657 static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 658                          const struct conf_info **conf, const char *trailer,
 659                          ssize_t separator_pos)
 660 {
 661         struct arg_item *item;
 662         size_t tok_len;
 663         struct list_head *pos;
 664
 665         if (separator_pos != -1) {
 666                 strbuf_add(tok, trailer, separator_pos);
 667                 strbuf_trim(tok);
 668                 strbuf_addstr(val, trailer + separator_pos + 1);
 669                 strbuf_trim(val);
 670         } else {
 671                 strbuf_addstr(tok, trailer);
 672                 strbuf_trim(tok);
 673         }
 674
 675         /* Lookup if the token matches something in the config */
 676         tok_len = token_len_without_separator(tok->buf, tok->len);
 677         if (conf)
 678                 *conf = &default_conf_info;
 679         list_for_each(pos, &conf_head) {
 680                 item = list_entry(pos, struct arg_item, list);
 681                 if (token_matches_item(tok->buf, item, tok_len)) {
 682                         char *tok_buf = strbuf_detach(tok, NULL);
 683                         if (conf)
 684                                 *conf = &item->conf;
 685                         strbuf_addstr(tok, token_from_item(item, tok_buf));
 686                         free(tok_buf);
 687                         break;
 688                 }
 689         }
 690 }
 691
 692 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 693                                              char *val)
 694 {
 695         struct trailer_item *new_item = xcalloc(1, sizeof(*new_item));
 696         new_item->token = tok;
 697         new_item->value = val;
 698         list_add_tail(&new_item->list, head);
 699         return new_item;
 700 }
 701
 702 static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 703                          const struct conf_info *conf,
 704                          const struct new_trailer_item *new_trailer_item)
 705 {
 706         struct arg_item *new_item = xcalloc(1, sizeof(*new_item));
 707         new_item->token = tok;
 708         new_item->value = val;
 709         duplicate_conf(&new_item->conf, conf);
 710         if (new_trailer_item) {
 711                 if (new_trailer_item->where != WHERE_DEFAULT)
 712                         new_item->conf.where = new_trailer_item->where;
 713                 if (new_trailer_item->if_exists != EXISTS_DEFAULT)
 714                         new_item->conf.if_exists = new_trailer_item->if_exists;
 715                 if (new_trailer_item->if_missing != MISSING_DEFAULT)
 716                         new_item->conf.if_missing = new_trailer_item->if_missing;
 717         }
 718         list_add_tail(&new_item->list, arg_head);
 719 }
 720
 721 void parse_trailers_from_config(struct list_head *config_head)
 722 {
 723         struct arg_item *item;
 724         struct list_head *pos;
 725
 726         /* Add an arg item for each configured trailer with a command */
 727         list_for_each(pos, &conf_head) {
 728                 item = list_entry(pos, struct arg_item, list);
 729                 if (item->conf.command)
 730                         add_arg_item(config_head,
 731                                      xstrdup(token_from_item(item, NULL)),
 732                                      xstrdup(""),
 733                                      &item->conf, NULL);
 734         }
 735 }
 736
 737 void parse_trailers_from_command_line_args(struct list_head *arg_head,
 738                                            struct list_head *new_trailer_head)
 739 {
 740         struct strbuf tok = STRBUF_INIT;
 741         struct strbuf val = STRBUF_INIT;
 742         const struct conf_info *conf;
 743         struct list_head *pos;
 744
 745         /*
 746          * In command-line arguments, '=' is accepted (in addition to the
 747          * separators that are defined).
 748          */
 749         char *cl_separators = xstrfmt("=%s", separators);
 750
 751         /* Add an arg item for each trailer on the command line */
 752         list_for_each(pos, new_trailer_head) {
 753                 struct new_trailer_item *tr =
 754                         list_entry(pos, struct new_trailer_item, list);
 755                 ssize_t separator_pos = find_separator(tr->text, cl_separators);
 756
 757                 if (separator_pos == 0) {
 758                         struct strbuf sb = STRBUF_INIT;
 759                         strbuf_addstr(&sb, tr->text);
 760                         strbuf_trim(&sb);
 761                         error(_("empty trailer token in trailer '%.*s'"),
 762                               (int) sb.len, sb.buf);
 763                         strbuf_release(&sb);
 764                 } else {
 765                         parse_trailer(&tok, &val, &conf, tr->text,
 766                                       separator_pos);
 767                         add_arg_item(arg_head,
 768                                      strbuf_detach(&tok, NULL),
 769                                      strbuf_detach(&val, NULL),
 770                                      conf, tr);
 771                 }
 772         }
 773
 774         free(cl_separators);
 775 }
 776
 777 static const char *next_line(const char *str)
 778 {
 779         const char *nl = strchrnul(str, '\n');
 780         return nl + !!*nl;
 781 }
 782
 783 /*
 784  * Return the position of the start of the last line. If len is 0, return -1.
 785  */
 786 static ssize_t last_line(const char *buf, size_t len)
 787 {
 788         ssize_t i;
 789         if (len == 0)
 790                 return -1;
 791         if (len == 1)
 792                 return 0;
 793         /*
 794          * Skip the last character (in addition to the null terminator),
 795          * because if the last character is a newline, it is considered as part
 796          * of the last line anyway.
 797          */
 798         i = len - 2;
 799
 800         for (; i >= 0; i--) {
 801                 if (buf[i] == '\n')
 802                         return i + 1;
 803         }
 804         return 0;
 805 }
 806
 807 /*
 808  * Find the end of the log message as an offset from the start of the input
 809  * (where callers of this function are interested in looking for a trailers
 810  * block in the same input). We have to consider two categories of content that
 811  * can come at the end of the input which we want to ignore (because they don't
 812  * belong in the log message):
 813  *
 814  * (1) the "patch part" which begins with a "---" divider and has patch
 815  * information (like the output of git-format-patch), and
 816  *
 817  * (2) any trailing comment lines, blank lines like in the output of "git
 818  * commit -v", or stuff below the "cut" (scissor) line.
 819  *
 820  * As a formula, the situation looks like this:
 821  *
 822  *     INPUT = LOG MESSAGE + IGNORED
 823  *
 824  * where IGNORED can be either of the two categories described above. It may be
 825  * that there is nothing to ignore. Now it may be the case that the LOG MESSAGE
 826  * contains a trailer block, but that's not the concern of this function.
 827  */
 828 static size_t find_end_of_log_message(const char *input, int no_divider)
 829 {
 830         size_t end;
 831         const char *s;
 832
 833         /* Assume the naive end of the input is already what we want. */
 834         end = strlen(input);
 835
 836         if (no_divider)
 837                 return end;
 838
 839         /* Optionally skip over any patch part ("---" line and below). */
 840         for (s = input; *s; s = next_line(s)) {
 841                 const char *v;
 842
 843                 if (skip_prefix(s, "---", &v) && isspace(*v)) {
 844                         end = s - input;
 845                         break;
 846                 }
 847         }
 848
 849         /* Skip over other ignorable bits. */
 850         return end - ignored_log_message_bytes(input, end);
 851 }
 852
 853 /*
 854  * Return the position of the first trailer line or len if there are no
 855  * trailers.
 856  */
 857 static size_t find_trailer_block_start(const char *buf, size_t len)
 858 {
 859         const char *s;
 860         ssize_t end_of_title, l;
 861         int only_spaces = 1;
 862         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 863         /*
 864          * Number of possible continuation lines encountered. This will be
 865          * reset to 0 if we encounter a trailer (since those lines are to be
 866          * considered continuations of that trailer), and added to
 867          * non_trailer_lines if we encounter a non-trailer (since those lines
 868          * are to be considered non-trailers).
 869          */
 870         int possible_continuation_lines = 0;
 871
 872         /* The first paragraph is the title and cannot be trailers */
 873         for (s = buf; s < buf + len; s = next_line(s)) {
 874                 if (s[0] == comment_line_char)
 875                         continue;
 876                 if (is_blank_line(s))
 877                         break;
 878         }
 879         end_of_title = s - buf;
 880
 881         /*
 882          * Get the start of the trailers by looking starting from the end for a
 883          * blank line before a set of non-blank lines that (i) are all
 884          * trailers, or (ii) contains at least one Git-generated trailer and
 885          * consists of at least 25% trailers.
 886          */
 887         for (l = last_line(buf, len);
 888              l >= end_of_title;
 889              l = last_line(buf, l)) {
 890                 const char *bol = buf + l;
 891                 const char **p;
 892                 ssize_t separator_pos;
 893
 894                 if (bol[0] == comment_line_char) {
 895                         non_trailer_lines += possible_continuation_lines;
 896                         possible_continuation_lines = 0;
 897                         continue;
 898                 }
 899                 if (is_blank_line(bol)) {
 900                         if (only_spaces)
 901                                 continue;
 902                         non_trailer_lines += possible_continuation_lines;
 903                         if (recognized_prefix &&
 904                             trailer_lines * 3 >= non_trailer_lines)
 905                                 return next_line(bol) - buf;
 906                         else if (trailer_lines && !non_trailer_lines)
 907                                 return next_line(bol) - buf;
 908                         return len;
 909                 }
 910                 only_spaces = 0;
 911
 912                 for (p = git_generated_prefixes; *p; p++) {
 913                         if (starts_with(bol, *p)) {
 914                                 trailer_lines++;
 915                                 possible_continuation_lines = 0;
 916                                 recognized_prefix = 1;
 917                                 goto continue_outer_loop;
 918                         }
 919                 }
 920
 921                 separator_pos = find_separator(bol, separators);
 922                 if (separator_pos >= 1 && !isspace(bol[0])) {
 923                         struct list_head *pos;
 924
 925                         trailer_lines++;
 926                         possible_continuation_lines = 0;
 927                         if (recognized_prefix)
 928                                 continue;
 929                         list_for_each(pos, &conf_head) {
 930                                 struct arg_item *item;
 931                                 item = list_entry(pos, struct arg_item, list);
 932                                 if (token_matches_item(bol, item,
 933                                                        separator_pos)) {
 934                                         recognized_prefix = 1;
 935                                         break;
 936                                 }
 937                         }
 938                 } else if (isspace(bol[0]))
 939                         possible_continuation_lines++;
 940                 else {
 941                         non_trailer_lines++;
 942                         non_trailer_lines += possible_continuation_lines;
 943                         possible_continuation_lines = 0;
 944                 }
 945 continue_outer_loop:
 946                 ;
 947         }
 948
 949         return len;
 950 }
 951
 952 static int ends_with_blank_line(const char *buf, size_t len)
 953 {
 954         ssize_t ll = last_line(buf, len);
 955         if (ll < 0)
 956                 return 0;
 957         return is_blank_line(buf + ll);
 958 }
 959
 960 static void unfold_value(struct strbuf *val)
 961 {
 962         struct strbuf out = STRBUF_INIT;
 963         size_t i;
 964
 965         strbuf_grow(&out, val->len);
 966         i = 0;
 967         while (i < val->len) {
 968                 char c = val->buf[i++];
 969                 if (c == '\n') {
 970                         /* Collapse continuation down to a single space. */
 971                         while (i < val->len && isspace(val->buf[i]))
 972                                 i++;
 973                         strbuf_addch(&out, ' ');
 974                 } else {
 975                         strbuf_addch(&out, c);
 976                 }
 977         }
 978
 979         /* Empty lines may have left us with whitespace cruft at the edges */
 980         strbuf_trim(&out);
 981
 982         /* output goes back to val as if we modified it in-place */
 983         strbuf_swap(&out, val);
 984         strbuf_release(&out);
 985 }
 986
 987 /*
 988  * Parse trailers in "str", populating the trailer info and "head"
 989  * linked list structure.
 990  */
 991 void parse_trailers(const struct process_trailer_options *opts,
 992                     struct trailer_info *info,
 993                     const char *str,
 994                     struct list_head *head)
 995 {
 996         struct strbuf tok = STRBUF_INIT;
 997         struct strbuf val = STRBUF_INIT;
 998         size_t i;
 999
1000         trailer_info_get(info, str, opts);
1001
1002         for (i = 0; i < info->trailer_nr; i++) {
1003                 int separator_pos;
1004                 char *trailer = info->trailers[i];
1005                 if (trailer[0] == comment_line_char)
1006                         continue;
1007                 separator_pos = find_separator(trailer, separators);
1008                 if (separator_pos >= 1) {
1009                         parse_trailer(&tok, &val, NULL, trailer,
1010                                       separator_pos);
1011                         if (opts->unfold)
1012                                 unfold_value(&val);
1013                         add_trailer_item(head,
1014                                          strbuf_detach(&tok, NULL),
1015                                          strbuf_detach(&val, NULL));
1016                 } else if (!opts->only_trailers) {
1017                         strbuf_addstr(&val, trailer);
1018                         strbuf_strip_suffix(&val, "\n");
1019                         add_trailer_item(head,
1020                                          NULL,
1021                                          strbuf_detach(&val, NULL));
1022                 }
1023         }
1024 }
1025
1026 void free_trailers(struct list_head *trailers)
1027 {
1028         struct list_head *pos, *p;
1029         list_for_each_safe(pos, p, trailers) {
1030                 list_del(pos);
1031                 free_trailer_item(list_entry(pos, struct trailer_item, list));
1032         }
1033 }
1034
1035 void trailer_info_get(struct trailer_info *info, const char *str,
1036                       const struct process_trailer_options *opts)
1037 {
1038         size_t end_of_log_message = 0, trailer_block_start = 0;
1039         struct strbuf **trailer_lines, **ptr;
1040         char **trailer_strings = NULL;
1041         size_t nr = 0, alloc = 0;
1042         char **last = NULL;
1043
1044         trailer_config_init();
1045
1046         end_of_log_message = find_end_of_log_message(str, opts->no_divider);
1047         trailer_block_start = find_trailer_block_start(str, end_of_log_message);
1048
1049         trailer_lines = strbuf_split_buf(str + trailer_block_start,
1050                                          end_of_log_message - trailer_block_start,
1051                                          '\n',
1052                                          0);
1053         for (ptr = trailer_lines; *ptr; ptr++) {
1054                 if (last && isspace((*ptr)->buf[0])) {
1055                         struct strbuf sb = STRBUF_INIT;
1056                         strbuf_attach(&sb, *last, strlen(*last), strlen(*last));
1057                         strbuf_addbuf(&sb, *ptr);
1058                         *last = strbuf_detach(&sb, NULL);
1059                         continue;
1060                 }
1061                 ALLOC_GROW(trailer_strings, nr + 1, alloc);
1062                 trailer_strings[nr] = strbuf_detach(*ptr, NULL);
1063                 last = find_separator(trailer_strings[nr], separators) >= 1
1064                         ? &trailer_strings[nr]
1065                         : NULL;
1066                 nr++;
1067         }
1068         strbuf_list_free(trailer_lines);
1069
1070         info->blank_line_before_trailer = ends_with_blank_line(str,
1071                                                                trailer_block_start);
1072         info->trailer_block_start = trailer_block_start;
1073         info->trailer_block_end = end_of_log_message;
1074         info->trailers = trailer_strings;
1075         info->trailer_nr = nr;
1076 }
1077
1078 void trailer_info_release(struct trailer_info *info)
1079 {
1080         size_t i;
1081         for (i = 0; i < info->trailer_nr; i++)
1082                 free(info->trailers[i]);
1083         free(info->trailers);
1084 }
1085
1086 static void format_trailer_info(const struct process_trailer_options *opts,
1087                                 const struct trailer_info *info,
1088                                 const char *msg,
1089                                 struct strbuf *out)
1090 {
1091         size_t origlen = out->len;
1092         size_t i;
1093
1094         /* If we want the whole block untouched, we can take the fast path. */
1095         if (!opts->only_trailers && !opts->unfold && !opts->filter &&
1096             !opts->separator && !opts->key_only && !opts->value_only &&
1097             !opts->key_value_separator) {
1098                 strbuf_add(out, msg + info->trailer_block_start,
1099                            info->trailer_block_end - info->trailer_block_start);
1100                 return;
1101         }
1102
1103         for (i = 0; i < info->trailer_nr; i++) {
1104                 char *trailer = info->trailers[i];
1105                 ssize_t separator_pos = find_separator(trailer, separators);
1106
1107                 if (separator_pos >= 1) {
1108                         struct strbuf tok = STRBUF_INIT;
1109                         struct strbuf val = STRBUF_INIT;
1110
1111                         parse_trailer(&tok, &val, NULL, trailer, separator_pos);
1112                         if (!opts->filter || opts->filter(&tok, opts->filter_data)) {
1113                                 if (opts->unfold)
1114                                         unfold_value(&val);
1115
1116                                 if (opts->separator && out->len != origlen)
1117                                         strbuf_addbuf(out, opts->separator);
1118                                 if (!opts->value_only)
1119                                         strbuf_addbuf(out, &tok);
1120                                 if (!opts->key_only && !opts->value_only) {
1121                                         if (opts->key_value_separator)
1122                                                 strbuf_addbuf(out, opts->key_value_separator);
1123                                         else
1124                                                 strbuf_addstr(out, ": ");
1125                                 }
1126                                 if (!opts->key_only)
1127                                         strbuf_addbuf(out, &val);
1128                                 if (!opts->separator)
1129                                         strbuf_addch(out, '\n');
1130                         }
1131                         strbuf_release(&tok);
1132                         strbuf_release(&val);
1133
1134                 } else if (!opts->only_trailers) {
1135                         if (opts->separator && out->len != origlen) {
1136                                 strbuf_addbuf(out, opts->separator);
1137                         }
1138                         strbuf_addstr(out, trailer);
1139                         if (opts->separator) {
1140                                 strbuf_rtrim(out);
1141                         }
1142                 }
1143         }
1144
1145 }
1146
1147 void format_trailers_from_commit(const struct process_trailer_options *opts,
1148                                  const char *msg,
1149                                  struct strbuf *out)
1150 {
1151         struct trailer_info info;
1152
1153         trailer_info_get(&info, msg, opts);
1154         format_trailer_info(opts, &info, msg, out);
1155         trailer_info_release(&info);
1156 }
1157
1158 void trailer_iterator_init(struct trailer_iterator *iter, const char *msg)
1159 {
1160         struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
1161         strbuf_init(&iter->key, 0);
1162         strbuf_init(&iter->val, 0);
1163         opts.no_divider = 1;
1164         trailer_info_get(&iter->internal.info, msg, &opts);
1165         iter->internal.cur = 0;
1166 }
1167
1168 int trailer_iterator_advance(struct trailer_iterator *iter)
1169 {
1170         while (iter->internal.cur < iter->internal.info.trailer_nr) {
1171                 char *trailer = iter->internal.info.trailers[iter->internal.cur++];
1172                 int separator_pos = find_separator(trailer, separators);
1173
1174                 if (separator_pos < 1)
1175                         continue; /* not a real trailer */
1176
1177                 strbuf_reset(&iter->key);
1178                 strbuf_reset(&iter->val);
1179                 parse_trailer(&iter->key, &iter->val, NULL,
1180                               trailer, separator_pos);
1181                 /* Always unfold values during iteration. */
1182                 unfold_value(&iter->val);
1183                 return 1;
1184         }
1185         return 0;
1186 }
1187
1188 void trailer_iterator_release(struct trailer_iterator *iter)
1189 {
1190         trailer_info_release(&iter->internal.info);
1191         strbuf_release(&iter->val);
1192         strbuf_release(&iter->key);
1193 }