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 "tempfile.h"
   9 #include "trailer.h"
  10 #include "list.h"
  11 /*
  12  * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  13  */
  14
  15 struct conf_info {
  16         char *name;
  17         char *key;
  18         char *command;
  19         char *cmd;
  20         enum trailer_where where;
  21         enum trailer_if_exists if_exists;
  22         enum trailer_if_missing if_missing;
  23 };
  24
  25 static struct conf_info default_conf_info;
  26
  27 struct trailer_item {
  28         struct list_head list;
  29         /*
  30          * If this is not a trailer line, the line is stored in value
  31          * (excluding the terminating newline) and token is NULL.
  32          */
  33         char *token;
  34         char *value;
  35 };
  36
  37 struct arg_item {
  38         struct list_head list;
  39         char *token;
  40         char *value;
  41         struct conf_info conf;
  42 };
  43
  44 static LIST_HEAD(conf_head);
  45
  46 static char *separators = ":";
  47
  48 static int configured;
  49
  50 #define TRAILER_ARG_STRING "$ARG"
  51
  52 static const char *git_generated_prefixes[] = {
  53         "Signed-off-by: ",
  54         "(cherry picked from commit ",
  55         NULL
  56 };
  57
  58 /* Iterate over the elements of the list. */
  59 #define list_for_each_dir(pos, head, is_reverse) \
  60         for (pos = is_reverse ? (head)->prev : (head)->next; \
  61                 pos != (head); \
  62                 pos = is_reverse ? pos->prev : pos->next)
  63
  64 static int after_or_end(enum trailer_where where)
  65 {
  66         return (where == WHERE_AFTER) || (where == WHERE_END);
  67 }
  68
  69 /*
  70  * Return the length of the string not including any final
  71  * punctuation. E.g., the input "Signed-off-by:" would return
  72  * 13, stripping the trailing punctuation but retaining
  73  * internal punctuation.
  74  */
  75 static size_t token_len_without_separator(const char *token, size_t len)
  76 {
  77         while (len > 0 && !isalnum(token[len - 1]))
  78                 len--;
  79         return len;
  80 }
  81
  82 static int same_token(struct trailer_item *a, struct arg_item *b)
  83 {
  84         size_t a_len, b_len, min_len;
  85
  86         if (!a->token)
  87                 return 0;
  88
  89         a_len = token_len_without_separator(a->token, strlen(a->token));
  90         b_len = token_len_without_separator(b->token, strlen(b->token));
  91         min_len = (a_len > b_len) ? b_len : a_len;
  92
  93         return !strncasecmp(a->token, b->token, min_len);
  94 }
  95
  96 static int same_value(struct trailer_item *a, struct arg_item *b)
  97 {
  98         return !strcasecmp(a->value, b->value);
  99 }
 100
 101 static int same_trailer(struct trailer_item *a, struct arg_item *b)
 102 {
 103         return same_token(a, b) && same_value(a, b);
 104 }
 105
 106 static inline int is_blank_line(const char *str)
 107 {
 108         const char *s = str;
 109         while (*s && *s != '\n' && isspace(*s))
 110                 s++;
 111         return !*s || *s == '\n';
 112 }
 113
 114 static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
 115 {
 116         const char *ptr = strstr(sb->buf, a);
 117         if (ptr)
 118                 strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
 119 }
 120
 121 static void free_trailer_item(struct trailer_item *item)
 122 {
 123         free(item->token);
 124         free(item->value);
 125         free(item);
 126 }
 127
 128 static void free_arg_item(struct arg_item *item)
 129 {
 130         free(item->conf.name);
 131         free(item->conf.key);
 132         free(item->conf.command);
 133         free(item->conf.cmd);
 134         free(item->token);
 135         free(item->value);
 136         free(item);
 137 }
 138
 139 static char last_non_space_char(const char *s)
 140 {
 141         int i;
 142         for (i = strlen(s) - 1; i >= 0; i--)
 143                 if (!isspace(s[i]))
 144                         return s[i];
 145         return '\0';
 146 }
 147
 148 static void print_tok_val(FILE *outfile, const char *tok, const char *val)
 149 {
 150         char c;
 151
 152         if (!tok) {
 153                 fprintf(outfile, "%s\n", val);
 154                 return;
 155         }
 156
 157         c = last_non_space_char(tok);
 158         if (!c)
 159                 return;
 160         if (strchr(separators, c))
 161                 fprintf(outfile, "%s%s\n", tok, val);
 162         else
 163                 fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 164 }
 165
 166 static void print_all(FILE *outfile, struct list_head *head,
 167                       const struct process_trailer_options *opts)
 168 {
 169         struct list_head *pos;
 170         struct trailer_item *item;
 171         list_for_each(pos, head) {
 172                 item = list_entry(pos, struct trailer_item, list);
 173                 if ((!opts->trim_empty || strlen(item->value) > 0) &&
 174                     (!opts->only_trailers || item->token))
 175                         print_tok_val(outfile, item->token, item->value);
 176         }
 177 }
 178
 179 static struct trailer_item *trailer_from_arg(struct arg_item *arg_tok)
 180 {
 181         struct trailer_item *new_item = xcalloc(1, sizeof(*new_item));
 182         new_item->token = arg_tok->token;
 183         new_item->value = arg_tok->value;
 184         arg_tok->token = arg_tok->value = NULL;
 185         free_arg_item(arg_tok);
 186         return new_item;
 187 }
 188
 189 static void add_arg_to_input_list(struct trailer_item *on_tok,
 190                                   struct arg_item *arg_tok)
 191 {
 192         int aoe = after_or_end(arg_tok->conf.where);
 193         struct trailer_item *to_add = trailer_from_arg(arg_tok);
 194         if (aoe)
 195                 list_add(&to_add->list, &on_tok->list);
 196         else
 197                 list_add_tail(&to_add->list, &on_tok->list);
 198 }
 199
 200 static int check_if_different(struct trailer_item *in_tok,
 201                               struct arg_item *arg_tok,
 202                               int check_all,
 203                               struct list_head *head)
 204 {
 205         enum trailer_where where = arg_tok->conf.where;
 206         struct list_head *next_head;
 207         do {
 208                 if (same_trailer(in_tok, arg_tok))
 209                         return 0;
 210                 /*
 211                  * if we want to add a trailer after another one,
 212                  * we have to check those before this one
 213                  */
 214                 next_head = after_or_end(where) ? in_tok->list.prev
 215                                                 : in_tok->list.next;
 216                 if (next_head == head)
 217                         break;
 218                 in_tok = list_entry(next_head, struct trailer_item, list);
 219         } while (check_all);
 220         return 1;
 221 }
 222
 223 static char *apply_command(struct conf_info *conf, const char *arg)
 224 {
 225         struct strbuf cmd = STRBUF_INIT;
 226         struct strbuf buf = STRBUF_INIT;
 227         struct child_process cp = CHILD_PROCESS_INIT;
 228         char *result;
 229
 230         if (conf->cmd) {
 231                 strbuf_addstr(&cmd, conf->cmd);
 232                 strvec_push(&cp.args, cmd.buf);
 233                 if (arg)
 234                         strvec_push(&cp.args, arg);
 235         } else if (conf->command) {
 236                 strbuf_addstr(&cmd, conf->command);
 237                 if (arg)
 238                         strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 239                 strvec_push(&cp.args, cmd.buf);
 240         }
 241         strvec_pushv(&cp.env, (const char **)local_repo_env);
 242         cp.no_stdin = 1;
 243         cp.use_shell = 1;
 244
 245         if (capture_command(&cp, &buf, 1024)) {
 246                 error(_("running trailer command '%s' failed"), cmd.buf);
 247                 strbuf_release(&buf);
 248                 result = xstrdup("");
 249         } else {
 250                 strbuf_trim(&buf);
 251                 result = strbuf_detach(&buf, NULL);
 252         }
 253
 254         strbuf_release(&cmd);
 255         return result;
 256 }
 257
 258 static void apply_item_command(struct trailer_item *in_tok, struct arg_item *arg_tok)
 259 {
 260         if (arg_tok->conf.command || arg_tok->conf.cmd) {
 261                 const char *arg;
 262                 if (arg_tok->value && arg_tok->value[0]) {
 263                         arg = arg_tok->value;
 264                 } else {
 265                         if (in_tok && in_tok->value)
 266                                 arg = xstrdup(in_tok->value);
 267                         else
 268                                 arg = xstrdup("");
 269                 }
 270                 arg_tok->value = apply_command(&arg_tok->conf, arg);
 271                 free((char *)arg);
 272         }
 273 }
 274
 275 static void apply_arg_if_exists(struct trailer_item *in_tok,
 276                                 struct arg_item *arg_tok,
 277                                 struct trailer_item *on_tok,
 278                                 struct list_head *head)
 279 {
 280         switch (arg_tok->conf.if_exists) {
 281         case EXISTS_DO_NOTHING:
 282                 free_arg_item(arg_tok);
 283                 break;
 284         case EXISTS_REPLACE:
 285                 apply_item_command(in_tok, arg_tok);
 286                 add_arg_to_input_list(on_tok, arg_tok);
 287                 list_del(&in_tok->list);
 288                 free_trailer_item(in_tok);
 289                 break;
 290         case EXISTS_ADD:
 291                 apply_item_command(in_tok, arg_tok);
 292                 add_arg_to_input_list(on_tok, arg_tok);
 293                 break;
 294         case EXISTS_ADD_IF_DIFFERENT:
 295                 apply_item_command(in_tok, arg_tok);
 296                 if (check_if_different(in_tok, arg_tok, 1, head))
 297                         add_arg_to_input_list(on_tok, arg_tok);
 298                 else
 299                         free_arg_item(arg_tok);
 300                 break;
 301         case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 302                 apply_item_command(in_tok, arg_tok);
 303                 if (check_if_different(on_tok, arg_tok, 0, head))
 304                         add_arg_to_input_list(on_tok, arg_tok);
 305                 else
 306                         free_arg_item(arg_tok);
 307                 break;
 308         default:
 309                 BUG("trailer.c: unhandled value %d",
 310                     arg_tok->conf.if_exists);
 311         }
 312 }
 313
 314 static void apply_arg_if_missing(struct list_head *head,
 315                                  struct arg_item *arg_tok)
 316 {
 317         enum trailer_where where;
 318         struct trailer_item *to_add;
 319
 320         switch (arg_tok->conf.if_missing) {
 321         case MISSING_DO_NOTHING:
 322                 free_arg_item(arg_tok);
 323                 break;
 324         case MISSING_ADD:
 325                 where = arg_tok->conf.where;
 326                 apply_item_command(NULL, arg_tok);
 327                 to_add = trailer_from_arg(arg_tok);
 328                 if (after_or_end(where))
 329                         list_add_tail(&to_add->list, head);
 330                 else
 331                         list_add(&to_add->list, head);
 332                 break;
 333         default:
 334                 BUG("trailer.c: unhandled value %d",
 335                     arg_tok->conf.if_missing);
 336         }
 337 }
 338
 339 static int find_same_and_apply_arg(struct list_head *head,
 340                                    struct arg_item *arg_tok)
 341 {
 342         struct list_head *pos;
 343         struct trailer_item *in_tok;
 344         struct trailer_item *on_tok;
 345
 346         enum trailer_where where = arg_tok->conf.where;
 347         int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 348         int backwards = after_or_end(where);
 349         struct trailer_item *start_tok;
 350
 351         if (list_empty(head))
 352                 return 0;
 353
 354         start_tok = list_entry(backwards ? head->prev : head->next,
 355                                struct trailer_item,
 356                                list);
 357
 358         list_for_each_dir(pos, head, backwards) {
 359                 in_tok = list_entry(pos, struct trailer_item, list);
 360                 if (!same_token(in_tok, arg_tok))
 361                         continue;
 362                 on_tok = middle ? in_tok : start_tok;
 363                 apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 364                 return 1;
 365         }
 366         return 0;
 367 }
 368
 369 static void process_trailers_lists(struct list_head *head,
 370                                    struct list_head *arg_head)
 371 {
 372         struct list_head *pos, *p;
 373         struct arg_item *arg_tok;
 374
 375         list_for_each_safe(pos, p, arg_head) {
 376                 int applied = 0;
 377                 arg_tok = list_entry(pos, struct arg_item, list);
 378
 379                 list_del(pos);
 380
 381                 applied = find_same_and_apply_arg(head, arg_tok);
 382
 383                 if (!applied)
 384                         apply_arg_if_missing(head, arg_tok);
 385         }
 386 }
 387
 388 int trailer_set_where(enum trailer_where *item, const char *value)
 389 {
 390         if (!value)
 391                 *item = WHERE_DEFAULT;
 392         else if (!strcasecmp("after", value))
 393                 *item = WHERE_AFTER;
 394         else if (!strcasecmp("before", value))
 395                 *item = WHERE_BEFORE;
 396         else if (!strcasecmp("end", value))
 397                 *item = WHERE_END;
 398         else if (!strcasecmp("start", value))
 399                 *item = WHERE_START;
 400         else
 401                 return -1;
 402         return 0;
 403 }
 404
 405 int trailer_set_if_exists(enum trailer_if_exists *item, const char *value)
 406 {
 407         if (!value)
 408                 *item = EXISTS_DEFAULT;
 409         else if (!strcasecmp("addIfDifferent", value))
 410                 *item = EXISTS_ADD_IF_DIFFERENT;
 411         else if (!strcasecmp("addIfDifferentNeighbor", value))
 412                 *item = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 413         else if (!strcasecmp("add", value))
 414                 *item = EXISTS_ADD;
 415         else if (!strcasecmp("replace", value))
 416                 *item = EXISTS_REPLACE;
 417         else if (!strcasecmp("doNothing", value))
 418                 *item = EXISTS_DO_NOTHING;
 419         else
 420                 return -1;
 421         return 0;
 422 }
 423
 424 int trailer_set_if_missing(enum trailer_if_missing *item, const char *value)
 425 {
 426         if (!value)
 427                 *item = MISSING_DEFAULT;
 428         else if (!strcasecmp("doNothing", value))
 429                 *item = MISSING_DO_NOTHING;
 430         else if (!strcasecmp("add", value))
 431                 *item = MISSING_ADD;
 432         else
 433                 return -1;
 434         return 0;
 435 }
 436
 437 static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 438 {
 439         *dst = *src;
 440         dst->name = xstrdup_or_null(src->name);
 441         dst->key = xstrdup_or_null(src->key);
 442         dst->command = xstrdup_or_null(src->command);
 443         dst->cmd = xstrdup_or_null(src->cmd);
 444 }
 445
 446 static struct arg_item *get_conf_item(const char *name)
 447 {
 448         struct list_head *pos;
 449         struct arg_item *item;
 450
 451         /* Look up item with same name */
 452         list_for_each(pos, &conf_head) {
 453                 item = list_entry(pos, struct arg_item, list);
 454                 if (!strcasecmp(item->conf.name, name))
 455                         return item;
 456         }
 457
 458         /* Item does not already exists, create it */
 459         CALLOC_ARRAY(item, 1);
 460         duplicate_conf(&item->conf, &default_conf_info);
 461         item->conf.name = xstrdup(name);
 462
 463         list_add_tail(&item->list, &conf_head);
 464
 465         return item;
 466 }
 467
 468 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_CMD,
 469                         TRAILER_WHERE, TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 470
 471 static struct {
 472         const char *name;
 473         enum trailer_info_type type;
 474 } trailer_config_items[] = {
 475         { "key", TRAILER_KEY },
 476         { "command", TRAILER_COMMAND },
 477         { "cmd", TRAILER_CMD },
 478         { "where", TRAILER_WHERE },
 479         { "ifexists", TRAILER_IF_EXISTS },
 480         { "ifmissing", TRAILER_IF_MISSING }
 481 };
 482
 483 static int git_trailer_default_config(const char *conf_key, const char *value,
 484                                       const struct config_context *ctx UNUSED,
 485                                       void *cb UNUSED)
 486 {
 487         const char *trailer_item, *variable_name;
 488
 489         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 490                 return 0;
 491
 492         variable_name = strrchr(trailer_item, '.');
 493         if (!variable_name) {
 494                 if (!strcmp(trailer_item, "where")) {
 495                         if (trailer_set_where(&default_conf_info.where,
 496                                               value) < 0)
 497                                 warning(_("unknown value '%s' for key '%s'"),
 498                                         value, conf_key);
 499                 } else if (!strcmp(trailer_item, "ifexists")) {
 500                         if (trailer_set_if_exists(&default_conf_info.if_exists,
 501                                                   value) < 0)
 502                                 warning(_("unknown value '%s' for key '%s'"),
 503                                         value, conf_key);
 504                 } else if (!strcmp(trailer_item, "ifmissing")) {
 505                         if (trailer_set_if_missing(&default_conf_info.if_missing,
 506                                                    value) < 0)
 507                                 warning(_("unknown value '%s' for key '%s'"),
 508                                         value, conf_key);
 509                 } else if (!strcmp(trailer_item, "separators")) {
 510                         separators = xstrdup(value);
 511                 }
 512         }
 513         return 0;
 514 }
 515
 516 static int git_trailer_config(const char *conf_key, const char *value,
 517                               const struct config_context *ctx UNUSED,
 518                               void *cb UNUSED)
 519 {
 520         const char *trailer_item, *variable_name;
 521         struct arg_item *item;
 522         struct conf_info *conf;
 523         char *name = NULL;
 524         enum trailer_info_type type;
 525         int i;
 526
 527         if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 528                 return 0;
 529
 530         variable_name = strrchr(trailer_item, '.');
 531         if (!variable_name)
 532                 return 0;
 533
 534         variable_name++;
 535         for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 536                 if (strcmp(trailer_config_items[i].name, variable_name))
 537                         continue;
 538                 name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 539                 type = trailer_config_items[i].type;
 540                 break;
 541         }
 542
 543         if (!name)
 544                 return 0;
 545
 546         item = get_conf_item(name);
 547         conf = &item->conf;
 548         free(name);
 549
 550         switch (type) {
 551         case TRAILER_KEY:
 552                 if (conf->key)
 553                         warning(_("more than one %s"), conf_key);
 554                 conf->key = xstrdup(value);
 555                 break;
 556         case TRAILER_COMMAND:
 557                 if (conf->command)
 558                         warning(_("more than one %s"), conf_key);
 559                 conf->command = xstrdup(value);
 560                 break;
 561         case TRAILER_CMD:
 562                 if (conf->cmd)
 563                         warning(_("more than one %s"), conf_key);
 564                 conf->cmd = xstrdup(value);
 565                 break;
 566         case TRAILER_WHERE:
 567                 if (trailer_set_where(&conf->where, value))
 568                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 569                 break;
 570         case TRAILER_IF_EXISTS:
 571                 if (trailer_set_if_exists(&conf->if_exists, value))
 572                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 573                 break;
 574         case TRAILER_IF_MISSING:
 575                 if (trailer_set_if_missing(&conf->if_missing, value))
 576                         warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 577                 break;
 578         default:
 579                 BUG("trailer.c: unhandled type %d", type);
 580         }
 581         return 0;
 582 }
 583
 584 static void ensure_configured(void)
 585 {
 586         if (configured)
 587                 return;
 588
 589         /* Default config must be setup first */
 590         default_conf_info.where = WHERE_END;
 591         default_conf_info.if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 592         default_conf_info.if_missing = MISSING_ADD;
 593         git_config(git_trailer_default_config, NULL);
 594         git_config(git_trailer_config, NULL);
 595         configured = 1;
 596 }
 597
 598 static const char *token_from_item(struct arg_item *item, char *tok)
 599 {
 600         if (item->conf.key)
 601                 return item->conf.key;
 602         if (tok)
 603                 return tok;
 604         return item->conf.name;
 605 }
 606
 607 static int token_matches_item(const char *tok, struct arg_item *item, size_t tok_len)
 608 {
 609         if (!strncasecmp(tok, item->conf.name, tok_len))
 610                 return 1;
 611         return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 612 }
 613
 614 /*
 615  * If the given line is of the form
 616  * "<token><optional whitespace><separator>..." or "<separator>...", return the
 617  * location of the separator. Otherwise, return -1.  The optional whitespace
 618  * is allowed there primarily to allow things like "Bug #43" where <token> is
 619  * "Bug" and <separator> is "#".
 620  *
 621  * The separator-starts-line case (in which this function returns 0) is
 622  * distinguished from the non-well-formed-line case (in which this function
 623  * returns -1) because some callers of this function need such a distinction.
 624  */
 625 static ssize_t find_separator(const char *line, const char *separators)
 626 {
 627         int whitespace_found = 0;
 628         const char *c;
 629         for (c = line; *c; c++) {
 630                 if (strchr(separators, *c))
 631                         return c - line;
 632                 if (!whitespace_found && (isalnum(*c) || *c == '-'))
 633                         continue;
 634                 if (c != line && (*c == ' ' || *c == '\t')) {
 635                         whitespace_found = 1;
 636                         continue;
 637                 }
 638                 break;
 639         }
 640         return -1;
 641 }
 642
 643 /*
 644  * Obtain the token, value, and conf from the given trailer.
 645  *
 646  * separator_pos must not be 0, since the token cannot be an empty string.
 647  *
 648  * If separator_pos is -1, interpret the whole trailer as a token.
 649  */
 650 static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 651                          const struct conf_info **conf, const char *trailer,
 652                          ssize_t separator_pos)
 653 {
 654         struct arg_item *item;
 655         size_t tok_len;
 656         struct list_head *pos;
 657
 658         if (separator_pos != -1) {
 659                 strbuf_add(tok, trailer, separator_pos);
 660                 strbuf_trim(tok);
 661                 strbuf_addstr(val, trailer + separator_pos + 1);
 662                 strbuf_trim(val);
 663         } else {
 664                 strbuf_addstr(tok, trailer);
 665                 strbuf_trim(tok);
 666         }
 667
 668         /* Lookup if the token matches something in the config */
 669         tok_len = token_len_without_separator(tok->buf, tok->len);
 670         if (conf)
 671                 *conf = &default_conf_info;
 672         list_for_each(pos, &conf_head) {
 673                 item = list_entry(pos, struct arg_item, list);
 674                 if (token_matches_item(tok->buf, item, tok_len)) {
 675                         char *tok_buf = strbuf_detach(tok, NULL);
 676                         if (conf)
 677                                 *conf = &item->conf;
 678                         strbuf_addstr(tok, token_from_item(item, tok_buf));
 679                         free(tok_buf);
 680                         break;
 681                 }
 682         }
 683 }
 684
 685 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 686                                              char *val)
 687 {
 688         struct trailer_item *new_item = xcalloc(1, sizeof(*new_item));
 689         new_item->token = tok;
 690         new_item->value = val;
 691         list_add_tail(&new_item->list, head);
 692         return new_item;
 693 }
 694
 695 static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 696                          const struct conf_info *conf,
 697                          const struct new_trailer_item *new_trailer_item)
 698 {
 699         struct arg_item *new_item = xcalloc(1, sizeof(*new_item));
 700         new_item->token = tok;
 701         new_item->value = val;
 702         duplicate_conf(&new_item->conf, conf);
 703         if (new_trailer_item) {
 704                 if (new_trailer_item->where != WHERE_DEFAULT)
 705                         new_item->conf.where = new_trailer_item->where;
 706                 if (new_trailer_item->if_exists != EXISTS_DEFAULT)
 707                         new_item->conf.if_exists = new_trailer_item->if_exists;
 708                 if (new_trailer_item->if_missing != MISSING_DEFAULT)
 709                         new_item->conf.if_missing = new_trailer_item->if_missing;
 710         }
 711         list_add_tail(&new_item->list, arg_head);
 712 }
 713
 714 static void process_command_line_args(struct list_head *arg_head,
 715                                       struct list_head *new_trailer_head)
 716 {
 717         struct arg_item *item;
 718         struct strbuf tok = STRBUF_INIT;
 719         struct strbuf val = STRBUF_INIT;
 720         const struct conf_info *conf;
 721         struct list_head *pos;
 722
 723         /*
 724          * In command-line arguments, '=' is accepted (in addition to the
 725          * separators that are defined).
 726          */
 727         char *cl_separators = xstrfmt("=%s", separators);
 728
 729         /* Add an arg item for each configured trailer with a command */
 730         list_for_each(pos, &conf_head) {
 731                 item = list_entry(pos, struct arg_item, list);
 732                 if (item->conf.command)
 733                         add_arg_item(arg_head,
 734                                      xstrdup(token_from_item(item, NULL)),
 735                                      xstrdup(""),
 736                                      &item->conf, NULL);
 737         }
 738
 739         /* Add an arg item for each trailer on the command line */
 740         list_for_each(pos, new_trailer_head) {
 741                 struct new_trailer_item *tr =
 742                         list_entry(pos, struct new_trailer_item, list);
 743                 ssize_t separator_pos = find_separator(tr->text, cl_separators);
 744
 745                 if (separator_pos == 0) {
 746                         struct strbuf sb = STRBUF_INIT;
 747                         strbuf_addstr(&sb, tr->text);
 748                         strbuf_trim(&sb);
 749                         error(_("empty trailer token in trailer '%.*s'"),
 750                               (int) sb.len, sb.buf);
 751                         strbuf_release(&sb);
 752                 } else {
 753                         parse_trailer(&tok, &val, &conf, tr->text,
 754                                       separator_pos);
 755                         add_arg_item(arg_head,
 756                                      strbuf_detach(&tok, NULL),
 757                                      strbuf_detach(&val, NULL),
 758                                      conf, tr);
 759                 }
 760         }
 761
 762         free(cl_separators);
 763 }
 764
 765 static void read_input_file(struct strbuf *sb, const char *file)
 766 {
 767         if (file) {
 768                 if (strbuf_read_file(sb, file, 0) < 0)
 769                         die_errno(_("could not read input file '%s'"), file);
 770         } else {
 771                 if (strbuf_read(sb, fileno(stdin), 0) < 0)
 772                         die_errno(_("could not read from stdin"));
 773         }
 774 }
 775
 776 static const char *next_line(const char *str)
 777 {
 778         const char *nl = strchrnul(str, '\n');
 779         return nl + !!*nl;
 780 }
 781
 782 /*
 783  * Return the position of the start of the last line. If len is 0, return -1.
 784  */
 785 static ssize_t last_line(const char *buf, size_t len)
 786 {
 787         ssize_t i;
 788         if (len == 0)
 789                 return -1;
 790         if (len == 1)
 791                 return 0;
 792         /*
 793          * Skip the last character (in addition to the null terminator),
 794          * because if the last character is a newline, it is considered as part
 795          * of the last line anyway.
 796          */
 797         i = len - 2;
 798
 799         for (; i >= 0; i--) {
 800                 if (buf[i] == '\n')
 801                         return i + 1;
 802         }
 803         return 0;
 804 }
 805
 806 /*
 807  * Return the position of the start of the patch or the length of str if there
 808  * is no patch in the message.
 809  */
 810 static size_t find_patch_start(const char *str)
 811 {
 812         const char *s;
 813
 814         for (s = str; *s; s = next_line(s)) {
 815                 const char *v;
 816
 817                 if (skip_prefix(s, "---", &v) && isspace(*v))
 818                         return s - str;
 819         }
 820
 821         return s - str;
 822 }
 823
 824 /*
 825  * Return the position of the first trailer line or len if there are no
 826  * trailers.
 827  */
 828 static size_t find_trailer_start(const char *buf, size_t len)
 829 {
 830         const char *s;
 831         ssize_t end_of_title, l;
 832         int only_spaces = 1;
 833         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 834         /*
 835          * Number of possible continuation lines encountered. This will be
 836          * reset to 0 if we encounter a trailer (since those lines are to be
 837          * considered continuations of that trailer), and added to
 838          * non_trailer_lines if we encounter a non-trailer (since those lines
 839          * are to be considered non-trailers).
 840          */
 841         int possible_continuation_lines = 0;
 842
 843         /* The first paragraph is the title and cannot be trailers */
 844         for (s = buf; s < buf + len; s = next_line(s)) {
 845                 if (s[0] == comment_line_char)
 846                         continue;
 847                 if (is_blank_line(s))
 848                         break;
 849         }
 850         end_of_title = s - buf;
 851
 852         /*
 853          * Get the start of the trailers by looking starting from the end for a
 854          * blank line before a set of non-blank lines that (i) are all
 855          * trailers, or (ii) contains at least one Git-generated trailer and
 856          * consists of at least 25% trailers.
 857          */
 858         for (l = last_line(buf, len);
 859              l >= end_of_title;
 860              l = last_line(buf, l)) {
 861                 const char *bol = buf + l;
 862                 const char **p;
 863                 ssize_t separator_pos;
 864
 865                 if (bol[0] == comment_line_char) {
 866                         non_trailer_lines += possible_continuation_lines;
 867                         possible_continuation_lines = 0;
 868                         continue;
 869                 }
 870                 if (is_blank_line(bol)) {
 871                         if (only_spaces)
 872                                 continue;
 873                         non_trailer_lines += possible_continuation_lines;
 874                         if (recognized_prefix &&
 875                             trailer_lines * 3 >= non_trailer_lines)
 876                                 return next_line(bol) - buf;
 877                         else if (trailer_lines && !non_trailer_lines)
 878                                 return next_line(bol) - buf;
 879                         return len;
 880                 }
 881                 only_spaces = 0;
 882
 883                 for (p = git_generated_prefixes; *p; p++) {
 884                         if (starts_with(bol, *p)) {
 885                                 trailer_lines++;
 886                                 possible_continuation_lines = 0;
 887                                 recognized_prefix = 1;
 888                                 goto continue_outer_loop;
 889                         }
 890                 }
 891
 892                 separator_pos = find_separator(bol, separators);
 893                 if (separator_pos >= 1 && !isspace(bol[0])) {
 894                         struct list_head *pos;
 895
 896                         trailer_lines++;
 897                         possible_continuation_lines = 0;
 898                         if (recognized_prefix)
 899                                 continue;
 900                         list_for_each(pos, &conf_head) {
 901                                 struct arg_item *item;
 902                                 item = list_entry(pos, struct arg_item, list);
 903                                 if (token_matches_item(bol, item,
 904                                                        separator_pos)) {
 905                                         recognized_prefix = 1;
 906                                         break;
 907                                 }
 908                         }
 909                 } else if (isspace(bol[0]))
 910                         possible_continuation_lines++;
 911                 else {
 912                         non_trailer_lines++;
 913                         non_trailer_lines += possible_continuation_lines;
 914                         possible_continuation_lines = 0;
 915                 }
 916 continue_outer_loop:
 917                 ;
 918         }
 919
 920         return len;
 921 }
 922
 923 /* Return the position of the end of the trailers. */
 924 static size_t find_trailer_end(const char *buf, size_t len)
 925 {
 926         return len - ignore_non_trailer(buf, len);
 927 }
 928
 929 static int ends_with_blank_line(const char *buf, size_t len)
 930 {
 931         ssize_t ll = last_line(buf, len);
 932         if (ll < 0)
 933                 return 0;
 934         return is_blank_line(buf + ll);
 935 }
 936
 937 static void unfold_value(struct strbuf *val)
 938 {
 939         struct strbuf out = STRBUF_INIT;
 940         size_t i;
 941
 942         strbuf_grow(&out, val->len);
 943         i = 0;
 944         while (i < val->len) {
 945                 char c = val->buf[i++];
 946                 if (c == '\n') {
 947                         /* Collapse continuation down to a single space. */
 948                         while (i < val->len && isspace(val->buf[i]))
 949                                 i++;
 950                         strbuf_addch(&out, ' ');
 951                 } else {
 952                         strbuf_addch(&out, c);
 953                 }
 954         }
 955
 956         /* Empty lines may have left us with whitespace cruft at the edges */
 957         strbuf_trim(&out);
 958
 959         /* output goes back to val as if we modified it in-place */
 960         strbuf_swap(&out, val);
 961         strbuf_release(&out);
 962 }
 963
 964 static size_t process_input_file(FILE *outfile,
 965                                  const char *str,
 966                                  struct list_head *head,
 967                                  const struct process_trailer_options *opts)
 968 {
 969         struct trailer_info info;
 970         struct strbuf tok = STRBUF_INIT;
 971         struct strbuf val = STRBUF_INIT;
 972         size_t i;
 973
 974         trailer_info_get(&info, str, opts);
 975
 976         /* Print lines before the trailers as is */
 977         if (!opts->only_trailers)
 978                 fwrite(str, 1, info.trailer_start - str, outfile);
 979
 980         if (!opts->only_trailers && !info.blank_line_before_trailer)
 981                 fprintf(outfile, "\n");
 982
 983         for (i = 0; i < info.trailer_nr; i++) {
 984                 int separator_pos;
 985                 char *trailer = info.trailers[i];
 986                 if (trailer[0] == comment_line_char)
 987                         continue;
 988                 separator_pos = find_separator(trailer, separators);
 989                 if (separator_pos >= 1) {
 990                         parse_trailer(&tok, &val, NULL, trailer,
 991                                       separator_pos);
 992                         if (opts->unfold)
 993                                 unfold_value(&val);
 994                         add_trailer_item(head,
 995                                          strbuf_detach(&tok, NULL),
 996                                          strbuf_detach(&val, NULL));
 997                 } else if (!opts->only_trailers) {
 998                         strbuf_addstr(&val, trailer);
 999                         strbuf_strip_suffix(&val, "\n");
1000                         add_trailer_item(head,
1001                                          NULL,
1002                                          strbuf_detach(&val, NULL));
1003                 }
1004         }
1005
1006         trailer_info_release(&info);
1007
1008         return info.trailer_end - str;
1009 }
1010
1011 static void free_all(struct list_head *head)
1012 {
1013         struct list_head *pos, *p;
1014         list_for_each_safe(pos, p, head) {
1015                 list_del(pos);
1016                 free_trailer_item(list_entry(pos, struct trailer_item, list));
1017         }
1018 }
1019
1020 static struct tempfile *trailers_tempfile;
1021
1022 static FILE *create_in_place_tempfile(const char *file)
1023 {
1024         struct stat st;
1025         struct strbuf filename_template = STRBUF_INIT;
1026         const char *tail;
1027         FILE *outfile;
1028
1029         if (stat(file, &st))
1030                 die_errno(_("could not stat %s"), file);
1031         if (!S_ISREG(st.st_mode))
1032                 die(_("file %s is not a regular file"), file);
1033         if (!(st.st_mode & S_IWUSR))
1034                 die(_("file %s is not writable by user"), file);
1035
1036         /* Create temporary file in the same directory as the original */
1037         tail = strrchr(file, '/');
1038         if (tail)
1039                 strbuf_add(&filename_template, file, tail - file + 1);
1040         strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
1041
1042         trailers_tempfile = xmks_tempfile_m(filename_template.buf, st.st_mode);
1043         strbuf_release(&filename_template);
1044         outfile = fdopen_tempfile(trailers_tempfile, "w");
1045         if (!outfile)
1046                 die_errno(_("could not open temporary file"));
1047
1048         return outfile;
1049 }
1050
1051 void process_trailers(const char *file,
1052                       const struct process_trailer_options *opts,
1053                       struct list_head *new_trailer_head)
1054 {
1055         LIST_HEAD(head);
1056         struct strbuf sb = STRBUF_INIT;
1057         size_t trailer_end;
1058         FILE *outfile = stdout;
1059
1060         ensure_configured();
1061
1062         read_input_file(&sb, file);
1063
1064         if (opts->in_place)
1065                 outfile = create_in_place_tempfile(file);
1066
1067         /* Print the lines before the trailers */
1068         trailer_end = process_input_file(outfile, sb.buf, &head, opts);
1069
1070         if (!opts->only_input) {
1071                 LIST_HEAD(arg_head);
1072                 process_command_line_args(&arg_head, new_trailer_head);
1073                 process_trailers_lists(&head, &arg_head);
1074         }
1075
1076         print_all(outfile, &head, opts);
1077
1078         free_all(&head);
1079
1080         /* Print the lines after the trailers as is */
1081         if (!opts->only_trailers)
1082                 fwrite(sb.buf + trailer_end, 1, sb.len - trailer_end, outfile);
1083
1084         if (opts->in_place)
1085                 if (rename_tempfile(&trailers_tempfile, file))
1086                         die_errno(_("could not rename temporary file to %s"), file);
1087
1088         strbuf_release(&sb);
1089 }
1090
1091 void trailer_info_get(struct trailer_info *info, const char *str,
1092                       const struct process_trailer_options *opts)
1093 {
1094         int patch_start, trailer_end, trailer_start;
1095         struct strbuf **trailer_lines, **ptr;
1096         char **trailer_strings = NULL;
1097         size_t nr = 0, alloc = 0;
1098         char **last = NULL;
1099
1100         ensure_configured();
1101
1102         if (opts->no_divider)
1103                 patch_start = strlen(str);
1104         else
1105                 patch_start = find_patch_start(str);
1106
1107         trailer_end = find_trailer_end(str, patch_start);
1108         trailer_start = find_trailer_start(str, trailer_end);
1109
1110         trailer_lines = strbuf_split_buf(str + trailer_start,
1111                                          trailer_end - trailer_start,
1112                                          '\n',
1113                                          0);
1114         for (ptr = trailer_lines; *ptr; ptr++) {
1115                 if (last && isspace((*ptr)->buf[0])) {
1116                         struct strbuf sb = STRBUF_INIT;
1117                         strbuf_attach(&sb, *last, strlen(*last), strlen(*last));
1118                         strbuf_addbuf(&sb, *ptr);
1119                         *last = strbuf_detach(&sb, NULL);
1120                         continue;
1121                 }
1122                 ALLOC_GROW(trailer_strings, nr + 1, alloc);
1123                 trailer_strings[nr] = strbuf_detach(*ptr, NULL);
1124                 last = find_separator(trailer_strings[nr], separators) >= 1
1125                         ? &trailer_strings[nr]
1126                         : NULL;
1127                 nr++;
1128         }
1129         strbuf_list_free(trailer_lines);
1130
1131         info->blank_line_before_trailer = ends_with_blank_line(str,
1132                                                                trailer_start);
1133         info->trailer_start = str + trailer_start;
1134         info->trailer_end = str + trailer_end;
1135         info->trailers = trailer_strings;
1136         info->trailer_nr = nr;
1137 }
1138
1139 void trailer_info_release(struct trailer_info *info)
1140 {
1141         size_t i;
1142         for (i = 0; i < info->trailer_nr; i++)
1143                 free(info->trailers[i]);
1144         free(info->trailers);
1145 }
1146
1147 static void format_trailer_info(struct strbuf *out,
1148                                 const struct trailer_info *info,
1149                                 const struct process_trailer_options *opts)
1150 {
1151         size_t origlen = out->len;
1152         size_t i;
1153
1154         /* If we want the whole block untouched, we can take the fast path. */
1155         if (!opts->only_trailers && !opts->unfold && !opts->filter &&
1156             !opts->separator && !opts->key_only && !opts->value_only &&
1157             !opts->key_value_separator) {
1158                 strbuf_add(out, info->trailer_start,
1159                            info->trailer_end - info->trailer_start);
1160                 return;
1161         }
1162
1163         for (i = 0; i < info->trailer_nr; i++) {
1164                 char *trailer = info->trailers[i];
1165                 ssize_t separator_pos = find_separator(trailer, separators);
1166
1167                 if (separator_pos >= 1) {
1168                         struct strbuf tok = STRBUF_INIT;
1169                         struct strbuf val = STRBUF_INIT;
1170
1171                         parse_trailer(&tok, &val, NULL, trailer, separator_pos);
1172                         if (!opts->filter || opts->filter(&tok, opts->filter_data)) {
1173                                 if (opts->unfold)
1174                                         unfold_value(&val);
1175
1176                                 if (opts->separator && out->len != origlen)
1177                                         strbuf_addbuf(out, opts->separator);
1178                                 if (!opts->value_only)
1179                                         strbuf_addbuf(out, &tok);
1180                                 if (!opts->key_only && !opts->value_only) {
1181                                         if (opts->key_value_separator)
1182                                                 strbuf_addbuf(out, opts->key_value_separator);
1183                                         else
1184                                                 strbuf_addstr(out, ": ");
1185                                 }
1186                                 if (!opts->key_only)
1187                                         strbuf_addbuf(out, &val);
1188                                 if (!opts->separator)
1189                                         strbuf_addch(out, '\n');
1190                         }
1191                         strbuf_release(&tok);
1192                         strbuf_release(&val);
1193
1194                 } else if (!opts->only_trailers) {
1195                         if (opts->separator && out->len != origlen) {
1196                                 strbuf_addbuf(out, opts->separator);
1197                         }
1198                         strbuf_addstr(out, trailer);
1199                         if (opts->separator) {
1200                                 strbuf_rtrim(out);
1201                         }
1202                 }
1203         }
1204
1205 }
1206
1207 void format_trailers_from_commit(struct strbuf *out, const char *msg,
1208                                  const struct process_trailer_options *opts)
1209 {
1210         struct trailer_info info;
1211
1212         trailer_info_get(&info, msg, opts);
1213         format_trailer_info(out, &info, opts);
1214         trailer_info_release(&info);
1215 }
1216
1217 void trailer_iterator_init(struct trailer_iterator *iter, const char *msg)
1218 {
1219         struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
1220         strbuf_init(&iter->key, 0);
1221         strbuf_init(&iter->val, 0);
1222         opts.no_divider = 1;
1223         trailer_info_get(&iter->info, msg, &opts);
1224         iter->cur = 0;
1225 }
1226
1227 int trailer_iterator_advance(struct trailer_iterator *iter)
1228 {
1229         while (iter->cur < iter->info.trailer_nr) {
1230                 char *trailer = iter->info.trailers[iter->cur++];
1231                 int separator_pos = find_separator(trailer, separators);
1232
1233                 if (separator_pos < 1)
1234                         continue; /* not a real trailer */
1235
1236                 strbuf_reset(&iter->key);
1237                 strbuf_reset(&iter->val);
1238                 parse_trailer(&iter->key, &iter->val, NULL,
1239                               trailer, separator_pos);
1240                 unfold_value(&iter->val);
1241                 return 1;
1242         }
1243         return 0;
1244 }
1245
1246 void trailer_iterator_release(struct trailer_iterator *iter)
1247 {
1248         trailer_info_release(&iter->info);
1249         strbuf_release(&iter->val);
1250         strbuf_release(&iter->key);
1251 }