git.oblomov.eu Git - git/blob - trailer.c

   1 #include "cache.h"
   2 #include "string-list.h"
   3 #include "run-command.h"
   4 #include "commit.h"
   5 #include "tempfile.h"
   6 #include "trailer.h"
   7 #include "list.h"
   8 /*
   9  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  10  */
  11
  12 enum action_where { WHERE_END, WHERE_AFTER, WHERE_BEFORE, WHERE_START };
  13 enum action_if_exists { EXISTS_ADD_IF_DIFFERENT_NEIGHBOR, EXISTS_ADD_IF_DIFFERENT,
  14                         EXISTS_ADD, EXISTS_REPLACE, EXISTS_DO_NOTHING };
  15 enum action_if_missing { MISSING_ADD, MISSING_DO_NOTHING };
  16
  17 struct conf_info {
  18         char *name;
  19         char *key;
  20         char *command;
  21         enum action_where where;
  22         enum action_if_exists if_exists;
  23         enum action_if_missing if_missing;
  24 };
  25
  26 static struct conf_info default_conf_info;
  27
  28 struct trailer_item {
  29         struct list_head list;
  30         /*
  31          * If this is not a trailer line, the line is stored in value
  32          * (excluding the terminating newline) and token is NULL.
  33          */
  34         char *token;
  35         char *value;
  36 };
  37
  38 struct arg_item {
  39         struct list_head list;
  40         char *token;
  41         char *value;
  42         struct conf_info conf;
  43 };
  44
  45 static LIST_HEAD(conf_head);
  46
  47 static char *separators = ":";
  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 action_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 contains_only_spaces(const char *str)
 106 {
 107         const char *s = str;
 108         while (*s && isspace(*s))
 109                 s++;
 110         return !*s;
 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->token);
 133         free(item->value);
 134         free(item);
 135 }
 136
 137 static char last_non_space_char(const char *s)
 138 {
 139         int i;
 140         for (i = strlen(s) - 1; i >= 0; i--)
 141                 if (!isspace(s[i]))
 142                         return s[i];
 143         return '\0';
 144 }
 145
 146 static void print_tok_val(FILE *outfile, const char *tok, const char *val)
 147 {
 148         char c;
 149
 150         if (!tok) {
 151                 fprintf(outfile, "%s\n", val);
 152                 return;
 153         }
 154
 155         c = last_non_space_char(tok);
 156         if (!c)
 157                 return;
 158         if (strchr(separators, c))
 159                 fprintf(outfile, "%s%s\n", tok, val);
 160         else
 161                 fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 162 }
 163
 164 static void print_all(FILE *outfile, struct list_head *head, int trim_empty)
 165 {
 166         struct list_head *pos;
 167         struct trailer_item *item;
 168         list_for_each(pos, head) {
 169                 item = list_entry(pos, struct trailer_item, list);
 170                 if (!trim_empty || strlen(item->value) > 0)
 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 = xcalloc(sizeof(*new), 1);
 178         new->token = arg_tok->token;
 179         new->value = arg_tok->value;
 180         arg_tok->token = arg_tok->value = NULL;
 181         free_arg_item(arg_tok);
 182         return new;
 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 action_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         }
 301 }
 302
 303 static void apply_arg_if_missing(struct list_head *head,
 304                                  struct arg_item *arg_tok)
 305 {
 306         enum action_where where;
 307         struct trailer_item *to_add;
 308
 309         switch (arg_tok->conf.if_missing) {
 310         case MISSING_DO_NOTHING:
 311                 free_arg_item(arg_tok);
 312                 break;
 313         case MISSING_ADD:
 314                 where = arg_tok->conf.where;
 315                 apply_item_command(NULL, arg_tok);
 316                 to_add = trailer_from_arg(arg_tok);
 317                 if (after_or_end(where))
 318                         list_add_tail(&to_add->list, head);
 319                 else
 320                         list_add(&to_add->list, head);
 321         }
 322 }
 323
 324 static int find_same_and_apply_arg(struct list_head *head,
 325                                    struct arg_item *arg_tok)
 326 {
 327         struct list_head *pos;
 328         struct trailer_item *in_tok;
 329         struct trailer_item *on_tok;
 330
 331         enum action_where where = arg_tok->conf.where;
 332         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 333         int backwards = after_or_end(where);
 334         struct trailer_item *start_tok;
 335
 336         if (list_empty(head))
 337                 return 0;
 338
 339         start_tok = list_entry(backwards ? head->prev : head->next,
 340                                struct trailer_item,
 341                                list);
 342
 343         list_for_each_dir(pos, head, backwards) {
 344                 in_tok = list_entry(pos, struct trailer_item, list);
 345                 if (!same_token(in_tok, arg_tok))
 346                         continue;
 347                 on_tok = middle ? in_tok : start_tok;
 348                 apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 349                 return 1;
 350         }
 351         return 0;
 352 }
 353
 354 static void process_trailers_lists(struct list_head *head,
 355                                    struct list_head *arg_head)
 356 {
 357         struct list_head *pos, *p;
 358         struct arg_item *arg_tok;
 359
 360         list_for_each_safe(pos, p, arg_head) {
 361                 int applied = 0;
 362                 arg_tok = list_entry(pos, struct arg_item, list);
 363
 364                 list_del(pos);
 365
 366                 applied = find_same_and_apply_arg(head, arg_tok);
 367
 368                 if (!applied)
 369                         apply_arg_if_missing(head, arg_tok);
 370         }
 371 }
 372
 373 static int set_where(struct conf_info *item, const char *value)
 374 {
 375         if (!strcasecmp("after", value))
 376                 item->where = WHERE_AFTER;
 377         else if (!strcasecmp("before", value))
 378                 item->where = WHERE_BEFORE;
 379         else if (!strcasecmp("end", value))
 380                 item->where = WHERE_END;
 381         else if (!strcasecmp("start", value))
 382                 item->where = WHERE_START;
 383         else
 384                 return -1;
 385         return 0;
 386 }
 387
 388 static int set_if_exists(struct conf_info *item, const char *value)
 389 {
 390         if (!strcasecmp("addIfDifferent", value))
 391                 item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 392         else if (!strcasecmp("addIfDifferentNeighbor", value))
 393                 item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 394         else if (!strcasecmp("add", value))
 395                 item->if_exists = EXISTS_ADD;
 396         else if (!strcasecmp("replace", value))
 397                 item->if_exists = EXISTS_REPLACE;
 398         else if (!strcasecmp("doNothing", value))
 399                 item->if_exists = EXISTS_DO_NOTHING;
 400         else
 401                 return -1;
 402         return 0;
 403 }
 404
 405 static int set_if_missing(struct conf_info *item, const char *value)
 406 {
 407         if (!strcasecmp("doNothing", value))
 408                 item->if_missing = MISSING_DO_NOTHING;
 409         else if (!strcasecmp("add", value))
 410                 item->if_missing = MISSING_ADD;
 411         else
 412                 return -1;
 413         return 0;
 414 }
 415
 416 static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 417 {
 418         *dst = *src;
 419         dst->name = xstrdup_or_null(src->name);
 420         dst->key = xstrdup_or_null(src->key);
 421         dst->command = xstrdup_or_null(src->command);
 422 }
 423
 424 static struct arg_item *get_conf_item(const char *name)
 425 {
 426         struct list_head *pos;
 427         struct arg_item *item;
 428
 429         /* Look up item with same name */
 430         list_for_each(pos, &conf_head) {
 431                 item = list_entry(pos, struct arg_item, list);
 432                 if (!strcasecmp(item->conf.name, name))
 433                         return item;
 434         }
 435
 436         /* Item does not already exists, create it */
 437         item = xcalloc(sizeof(*item), 1);
 438         duplicate_conf(&item->conf, &default_conf_info);
 439         item->conf.name = xstrdup(name);
 440
 441         list_add_tail(&item->list, &conf_head);
 442
 443         return item;
 444 }
 445
 446 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 447                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 448
 449 static struct {
 450         const char *name;
 451         enum trailer_info_type type;
 452 } trailer_config_items[] = {
 453         { "key", TRAILER_KEY },
 454         { "command", TRAILER_COMMAND },
 455         { "where", TRAILER_WHERE },
 456         { "ifexists", TRAILER_IF_EXISTS },
 457         { "ifmissing", TRAILER_IF_MISSING }
 458 };
 459
 460 static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 461 {
 462         const char *trailer_item, *variable_name;
 463
 464         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 465                 return 0;
 466
 467         variable_name = strrchr(trailer_item, '.');
 468         if (!variable_name) {
 469                 if (!strcmp(trailer_item, "where")) {
 470                         if (set_where(&default_conf_info, value) < 0)
 471                                 warning(_("unknown value '%s' for key '%s'"),
 472                                         value, conf_key);
 473                 } else if (!strcmp(trailer_item, "ifexists")) {
 474                         if (set_if_exists(&default_conf_info, value) < 0)
 475                                 warning(_("unknown value '%s' for key '%s'"),
 476                                         value, conf_key);
 477                 } else if (!strcmp(trailer_item, "ifmissing")) {
 478                         if (set_if_missing(&default_conf_info, value) < 0)
 479                                 warning(_("unknown value '%s' for key '%s'"),
 480                                         value, conf_key);
 481                 } else if (!strcmp(trailer_item, "separators")) {
 482                         separators = xstrdup(value);
 483                 }
 484         }
 485         return 0;
 486 }
 487
 488 static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 489 {
 490         const char *trailer_item, *variable_name;
 491         struct arg_item *item;
 492         struct conf_info *conf;
 493         char *name = NULL;
 494         enum trailer_info_type type;
 495         int i;
 496
 497         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 498                 return 0;
 499
 500         variable_name = strrchr(trailer_item, '.');
 501         if (!variable_name)
 502                 return 0;
 503
 504         variable_name++;
 505         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 506                 if (strcmp(trailer_config_items[i].name, variable_name))
 507                         continue;
 508                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 509                 type = trailer_config_items[i].type;
 510                 break;
 511         }
 512
 513         if (!name)
 514                 return 0;
 515
 516         item = get_conf_item(name);
 517         conf = &item->conf;
 518         free(name);
 519
 520         switch (type) {
 521         case TRAILER_KEY:
 522                 if (conf->key)
 523                         warning(_("more than one %s"), conf_key);
 524                 conf->key = xstrdup(value);
 525                 break;
 526         case TRAILER_COMMAND:
 527                 if (conf->command)
 528                         warning(_("more than one %s"), conf_key);
 529                 conf->command = xstrdup(value);
 530                 break;
 531         case TRAILER_WHERE:
 532                 if (set_where(conf, value))
 533                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 534                 break;
 535         case TRAILER_IF_EXISTS:
 536                 if (set_if_exists(conf, value))
 537                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 538                 break;
 539         case TRAILER_IF_MISSING:
 540                 if (set_if_missing(conf, value))
 541                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 542                 break;
 543         default:
 544                 die("BUG: trailer.c: unhandled type %d", type);
 545         }
 546         return 0;
 547 }
 548
 549 static const char *token_from_item(struct arg_item *item, char *tok)
 550 {
 551         if (item->conf.key)
 552                 return item->conf.key;
 553         if (tok)
 554                 return tok;
 555         return item->conf.name;
 556 }
 557
 558 static int token_matches_item(const char *tok, struct arg_item *item, int tok_len)
 559 {
 560         if (!strncasecmp(tok, item->conf.name, tok_len))
 561                 return 1;
 562         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 563 }
 564
 565 /*
 566  * If the given line is of the form
 567  * "<token><optional whitespace><separator>..." or "<separator>...", return the
 568  * location of the separator. Otherwise, return -1.  The optional whitespace
 569  * is allowed there primarily to allow things like "Bug #43" where <token> is
 570  * "Bug" and <separator> is "#".
 571  *
 572  * The separator-starts-line case (in which this function returns 0) is
 573  * distinguished from the non-well-formed-line case (in which this function
 574  * returns -1) because some callers of this function need such a distinction.
 575  */
 576 static int find_separator(const char *line, const char *separators)
 577 {
 578         int whitespace_found = 0;
 579         const char *c;
 580         for (c = line; *c; c++) {
 581                 if (strchr(separators, *c))
 582                         return c - line;
 583                 if (!whitespace_found && (isalnum(*c) || *c == '-'))
 584                         continue;
 585                 if (c != line && (*c == ' ' || *c == '\t')) {
 586                         whitespace_found = 1;
 587                         continue;
 588                 }
 589                 break;
 590         }
 591         return -1;
 592 }
 593
 594 /*
 595  * Obtain the token, value, and conf from the given trailer.
 596  *
 597  * separator_pos must not be 0, since the token cannot be an empty string.
 598  *
 599  * If separator_pos is -1, interpret the whole trailer as a token.
 600  */
 601 static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 602                          const struct conf_info **conf, const char *trailer,
 603                          int separator_pos)
 604 {
 605         struct arg_item *item;
 606         int tok_len;
 607         struct list_head *pos;
 608
 609         if (separator_pos != -1) {
 610                 strbuf_add(tok, trailer, separator_pos);
 611                 strbuf_trim(tok);
 612                 strbuf_addstr(val, trailer + separator_pos + 1);
 613                 strbuf_trim(val);
 614         } else {
 615                 strbuf_addstr(tok, trailer);
 616                 strbuf_trim(tok);
 617         }
 618
 619         /* Lookup if the token matches something in the config */
 620         tok_len = token_len_without_separator(tok->buf, tok->len);
 621         if (conf)
 622                 *conf = &default_conf_info;
 623         list_for_each(pos, &conf_head) {
 624                 item = list_entry(pos, struct arg_item, list);
 625                 if (token_matches_item(tok->buf, item, tok_len)) {
 626                         char *tok_buf = strbuf_detach(tok, NULL);
 627                         if (conf)
 628                                 *conf = &item->conf;
 629                         strbuf_addstr(tok, token_from_item(item, tok_buf));
 630                         free(tok_buf);
 631                         break;
 632                 }
 633         }
 634 }
 635
 636 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 637                                              char *val)
 638 {
 639         struct trailer_item *new = xcalloc(sizeof(*new), 1);
 640         new->token = tok;
 641         new->value = val;
 642         list_add_tail(&new->list, head);
 643         return new;
 644 }
 645
 646 static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 647                          const struct conf_info *conf)
 648 {
 649         struct arg_item *new = xcalloc(sizeof(*new), 1);
 650         new->token = tok;
 651         new->value = val;
 652         duplicate_conf(&new->conf, conf);
 653         list_add_tail(&new->list, arg_head);
 654 }
 655
 656 static void process_command_line_args(struct list_head *arg_head,
 657                                       struct string_list *trailers)
 658 {
 659         struct string_list_item *tr;
 660         struct arg_item *item;
 661         struct strbuf tok = STRBUF_INIT;
 662         struct strbuf val = STRBUF_INIT;
 663         const struct conf_info *conf;
 664         struct list_head *pos;
 665
 666         /*
 667          * In command-line arguments, '=' is accepted (in addition to the
 668          * separators that are defined).
 669          */
 670         char *cl_separators = xstrfmt("=%s", separators);
 671
 672         /* Add an arg item for each configured trailer with a command */
 673         list_for_each(pos, &conf_head) {
 674                 item = list_entry(pos, struct arg_item, list);
 675                 if (item->conf.command)
 676                         add_arg_item(arg_head,
 677                                      xstrdup(token_from_item(item, NULL)),
 678                                      xstrdup(""),
 679                                      &item->conf);
 680         }
 681
 682         /* Add an arg item for each trailer on the command line */
 683         for_each_string_list_item(tr, trailers) {
 684                 int separator_pos = find_separator(tr->string, cl_separators);
 685                 if (separator_pos == 0) {
 686                         struct strbuf sb = STRBUF_INIT;
 687                         strbuf_addstr(&sb, tr->string);
 688                         strbuf_trim(&sb);
 689                         error(_("empty trailer token in trailer '%.*s'"),
 690                               (int) sb.len, sb.buf);
 691                         strbuf_release(&sb);
 692                 } else {
 693                         parse_trailer(&tok, &val, &conf, tr->string,
 694                                       separator_pos);
 695                         add_arg_item(arg_head,
 696                                      strbuf_detach(&tok, NULL),
 697                                      strbuf_detach(&val, NULL),
 698                                      conf);
 699                 }
 700         }
 701
 702         free(cl_separators);
 703 }
 704
 705 static struct strbuf **read_input_file(const char *file)
 706 {
 707         struct strbuf **lines;
 708         struct strbuf sb = STRBUF_INIT;
 709
 710         if (file) {
 711                 if (strbuf_read_file(&sb, file, 0) < 0)
 712                         die_errno(_("could not read input file '%s'"), file);
 713         } else {
 714                 if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 715                         die_errno(_("could not read from stdin"));
 716         }
 717
 718         lines = strbuf_split(&sb, '\n');
 719
 720         strbuf_release(&sb);
 721
 722         return lines;
 723 }
 724
 725 /*
 726  * Return the (0 based) index of the start of the patch or the line
 727  * count if there is no patch in the message.
 728  */
 729 static int find_patch_start(struct strbuf **lines, int count)
 730 {
 731         int i;
 732
 733         /* Get the start of the patch part if any */
 734         for (i = 0; i < count; i++) {
 735                 if (starts_with(lines[i]->buf, "---"))
 736                         return i;
 737         }
 738
 739         return count;
 740 }
 741
 742 /*
 743  * Return the (0 based) index of the first trailer line or count if
 744  * there are no trailers. Trailers are searched only in the lines from
 745  * index (count - 1) down to index 0.
 746  */
 747 static int find_trailer_start(struct strbuf **lines, int count)
 748 {
 749         int start, end_of_title, only_spaces = 1;
 750         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 751         /*
 752          * Number of possible continuation lines encountered. This will be
 753          * reset to 0 if we encounter a trailer (since those lines are to be
 754          * considered continuations of that trailer), and added to
 755          * non_trailer_lines if we encounter a non-trailer (since those lines
 756          * are to be considered non-trailers).
 757          */
 758         int possible_continuation_lines = 0;
 759
 760         /* The first paragraph is the title and cannot be trailers */
 761         for (start = 0; start < count; start++) {
 762                 if (lines[start]->buf[0] == comment_line_char)
 763                         continue;
 764                 if (contains_only_spaces(lines[start]->buf))
 765                         break;
 766         }
 767         end_of_title = start;
 768
 769         /*
 770          * Get the start of the trailers by looking starting from the end for a
 771          * blank line before a set of non-blank lines that (i) are all
 772          * trailers, or (ii) contains at least one Git-generated trailer and
 773          * consists of at least 25% trailers.
 774          */
 775         for (start = count - 1; start >= end_of_title; start--) {
 776                 const char **p;
 777                 int separator_pos;
 778
 779                 if (lines[start]->buf[0] == comment_line_char) {
 780                         non_trailer_lines += possible_continuation_lines;
 781                         possible_continuation_lines = 0;
 782                         continue;
 783                 }
 784                 if (contains_only_spaces(lines[start]->buf)) {
 785                         if (only_spaces)
 786                                 continue;
 787                         non_trailer_lines += possible_continuation_lines;
 788                         if (recognized_prefix &&
 789                             trailer_lines * 3 >= non_trailer_lines)
 790                                 return start + 1;
 791                         if (trailer_lines && !non_trailer_lines)
 792                                 return start + 1;
 793                         return count;
 794                 }
 795                 only_spaces = 0;
 796
 797                 for (p = git_generated_prefixes; *p; p++) {
 798                         if (starts_with(lines[start]->buf, *p)) {
 799                                 trailer_lines++;
 800                                 possible_continuation_lines = 0;
 801                                 recognized_prefix = 1;
 802                                 goto continue_outer_loop;
 803                         }
 804                 }
 805
 806                 separator_pos = find_separator(lines[start]->buf, separators);
 807                 if (separator_pos >= 1 && !isspace(lines[start]->buf[0])) {
 808                         struct list_head *pos;
 809
 810                         trailer_lines++;
 811                         possible_continuation_lines = 0;
 812                         if (recognized_prefix)
 813                                 continue;
 814                         list_for_each(pos, &conf_head) {
 815                                 struct arg_item *item;
 816                                 item = list_entry(pos, struct arg_item, list);
 817                                 if (token_matches_item(lines[start]->buf, item,
 818                                                        separator_pos)) {
 819                                         recognized_prefix = 1;
 820                                         break;
 821                                 }
 822                         }
 823                 } else if (isspace(lines[start]->buf[0]))
 824                         possible_continuation_lines++;
 825                 else {
 826                         non_trailer_lines++;
 827                         non_trailer_lines += possible_continuation_lines;
 828                         possible_continuation_lines = 0;
 829                 }
 830 continue_outer_loop:
 831                 ;
 832         }
 833
 834         return count;
 835 }
 836
 837 /* Get the index of the end of the trailers */
 838 static int find_trailer_end(struct strbuf **lines, int patch_start)
 839 {
 840         struct strbuf sb = STRBUF_INIT;
 841         int i, ignore_bytes;
 842
 843         for (i = 0; i < patch_start; i++)
 844                 strbuf_addbuf(&sb, lines[i]);
 845         ignore_bytes = ignore_non_trailer(&sb);
 846         strbuf_release(&sb);
 847         for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 848                 ignore_bytes -= lines[i]->len;
 849
 850         return i + 1;
 851 }
 852
 853 static int has_blank_line_before(struct strbuf **lines, int start)
 854 {
 855         for (;start >= 0; start--) {
 856                 if (lines[start]->buf[0] == comment_line_char)
 857                         continue;
 858                 return contains_only_spaces(lines[start]->buf);
 859         }
 860         return 0;
 861 }
 862
 863 static void print_lines(FILE *outfile, struct strbuf **lines, int start, int end)
 864 {
 865         int i;
 866         for (i = start; lines[i] && i < end; i++)
 867                 fprintf(outfile, "%s", lines[i]->buf);
 868 }
 869
 870 static int process_input_file(FILE *outfile,
 871                               struct strbuf **lines,
 872                               struct list_head *head)
 873 {
 874         int count = 0;
 875         int patch_start, trailer_start, trailer_end, i;
 876         struct strbuf tok = STRBUF_INIT;
 877         struct strbuf val = STRBUF_INIT;
 878         struct trailer_item *last = NULL;
 879
 880         /* Get the line count */
 881         while (lines[count])
 882                 count++;
 883
 884         patch_start = find_patch_start(lines, count);
 885         trailer_end = find_trailer_end(lines, patch_start);
 886         trailer_start = find_trailer_start(lines, trailer_end);
 887
 888         /* Print lines before the trailers as is */
 889         print_lines(outfile, lines, 0, trailer_start);
 890
 891         if (!has_blank_line_before(lines, trailer_start - 1))
 892                 fprintf(outfile, "\n");
 893
 894         /* Parse trailer lines */
 895         for (i = trailer_start; i < trailer_end; i++) {
 896                 int separator_pos;
 897                 if (lines[i]->buf[0] == comment_line_char)
 898                         continue;
 899                 if (last && isspace(lines[i]->buf[0])) {
 900                         struct strbuf sb = STRBUF_INIT;
 901                         strbuf_addf(&sb, "%s\n%s", last->value, lines[i]->buf);
 902                         strbuf_strip_suffix(&sb, "\n");
 903                         free(last->value);
 904                         last->value = strbuf_detach(&sb, NULL);
 905                         continue;
 906                 }
 907                 separator_pos = find_separator(lines[i]->buf, separators);
 908                 if (separator_pos >= 1) {
 909                         parse_trailer(&tok, &val, NULL, lines[i]->buf,
 910                                       separator_pos);
 911                         last = add_trailer_item(head,
 912                                                 strbuf_detach(&tok, NULL),
 913                                                 strbuf_detach(&val, NULL));
 914                 } else {
 915                         strbuf_addbuf(&val, lines[i]);
 916                         strbuf_strip_suffix(&val, "\n");
 917                         add_trailer_item(head,
 918                                          NULL,
 919                                          strbuf_detach(&val, NULL));
 920                         last = NULL;
 921                 }
 922         }
 923
 924         return trailer_end;
 925 }
 926
 927 static void free_all(struct list_head *head)
 928 {
 929         struct list_head *pos, *p;
 930         list_for_each_safe(pos, p, head) {
 931                 list_del(pos);
 932                 free_trailer_item(list_entry(pos, struct trailer_item, list));
 933         }
 934 }
 935
 936 static struct tempfile trailers_tempfile;
 937
 938 static FILE *create_in_place_tempfile(const char *file)
 939 {
 940         struct stat st;
 941         struct strbuf template = STRBUF_INIT;
 942         const char *tail;
 943         FILE *outfile;
 944
 945         if (stat(file, &st))
 946                 die_errno(_("could not stat %s"), file);
 947         if (!S_ISREG(st.st_mode))
 948                 die(_("file %s is not a regular file"), file);
 949         if (!(st.st_mode & S_IWUSR))
 950                 die(_("file %s is not writable by user"), file);
 951
 952         /* Create temporary file in the same directory as the original */
 953         tail = strrchr(file, '/');
 954         if (tail != NULL)
 955                 strbuf_add(&template, file, tail - file + 1);
 956         strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 957
 958         xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 959         strbuf_release(&template);
 960         outfile = fdopen_tempfile(&trailers_tempfile, "w");
 961         if (!outfile)
 962                 die_errno(_("could not open temporary file"));
 963
 964         return outfile;
 965 }
 966
 967 void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
 968 {
 969         LIST_HEAD(head);
 970         LIST_HEAD(arg_head);
 971         struct strbuf **lines;
 972         int trailer_end;
 973         FILE *outfile = stdout;
 974
 975         /* Default config must be setup first */
 976         git_config(git_trailer_default_config, NULL);
 977         git_config(git_trailer_config, NULL);
 978
 979         lines = read_input_file(file);
 980
 981         if (in_place)
 982                 outfile = create_in_place_tempfile(file);
 983
 984         /* Print the lines before the trailers */
 985         trailer_end = process_input_file(outfile, lines, &head);
 986
 987         process_command_line_args(&arg_head, trailers);
 988
 989         process_trailers_lists(&head, &arg_head);
 990
 991         print_all(outfile, &head, trim_empty);
 992
 993         free_all(&head);
 994
 995         /* Print the lines after the trailers as is */
 996         print_lines(outfile, lines, trailer_end, INT_MAX);
 997
 998         if (in_place)
 999                 if (rename_tempfile(&trailers_tempfile, file))
1000                         die_errno(_("could not rename temporary file to %s"), file);
1001
1002         strbuf_list_free(lines);
1003 }