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 parse_trailers_from_config(struct list_head *config_head)
 715 {
 716         struct arg_item *item;
 717         struct list_head *pos;
 718
 719         /* Add an arg item for each configured trailer with a command */
 720         list_for_each(pos, &conf_head) {
 721                 item = list_entry(pos, struct arg_item, list);
 722                 if (item->conf.command)
 723                         add_arg_item(config_head,
 724                                      xstrdup(token_from_item(item, NULL)),
 725                                      xstrdup(""),
 726                                      &item->conf, NULL);
 727         }
 728 }
 729
 730 static void parse_trailers_from_command_line_args(struct list_head *arg_head,
 731                                                   struct list_head *new_trailer_head)
 732 {
 733         struct strbuf tok = STRBUF_INIT;
 734         struct strbuf val = STRBUF_INIT;
 735         const struct conf_info *conf;
 736         struct list_head *pos;
 737
 738         /*
 739          * In command-line arguments, '=' is accepted (in addition to the
 740          * separators that are defined).
 741          */
 742         char *cl_separators = xstrfmt("=%s", separators);
 743
 744         /* Add an arg item for each trailer on the command line */
 745         list_for_each(pos, new_trailer_head) {
 746                 struct new_trailer_item *tr =
 747                         list_entry(pos, struct new_trailer_item, list);
 748                 ssize_t separator_pos = find_separator(tr->text, cl_separators);
 749
 750                 if (separator_pos == 0) {
 751                         struct strbuf sb = STRBUF_INIT;
 752                         strbuf_addstr(&sb, tr->text);
 753                         strbuf_trim(&sb);
 754                         error(_("empty trailer token in trailer '%.*s'"),
 755                               (int) sb.len, sb.buf);
 756                         strbuf_release(&sb);
 757                 } else {
 758                         parse_trailer(&tok, &val, &conf, tr->text,
 759                                       separator_pos);
 760                         add_arg_item(arg_head,
 761                                      strbuf_detach(&tok, NULL),
 762                                      strbuf_detach(&val, NULL),
 763                                      conf, tr);
 764                 }
 765         }
 766
 767         free(cl_separators);
 768 }
 769
 770 static void read_input_file(struct strbuf *sb, const char *file)
 771 {
 772         if (file) {
 773                 if (strbuf_read_file(sb, file, 0) < 0)
 774                         die_errno(_("could not read input file '%s'"), file);
 775         } else {
 776                 if (strbuf_read(sb, fileno(stdin), 0) < 0)
 777                         die_errno(_("could not read from stdin"));
 778         }
 779 }
 780
 781 static const char *next_line(const char *str)
 782 {
 783         const char *nl = strchrnul(str, '\n');
 784         return nl + !!*nl;
 785 }
 786
 787 /*
 788  * Return the position of the start of the last line. If len is 0, return -1.
 789  */
 790 static ssize_t last_line(const char *buf, size_t len)
 791 {
 792         ssize_t i;
 793         if (len == 0)
 794                 return -1;
 795         if (len == 1)
 796                 return 0;
 797         /*
 798          * Skip the last character (in addition to the null terminator),
 799          * because if the last character is a newline, it is considered as part
 800          * of the last line anyway.
 801          */
 802         i = len - 2;
 803
 804         for (; i >= 0; i--) {
 805                 if (buf[i] == '\n')
 806                         return i + 1;
 807         }
 808         return 0;
 809 }
 810
 811 /*
 812  * Find the end of the log message as an offset from the start of the input
 813  * (where callers of this function are interested in looking for a trailers
 814  * block in the same input). We have to consider two categories of content that
 815  * can come at the end of the input which we want to ignore (because they don't
 816  * belong in the log message):
 817  *
 818  * (1) the "patch part" which begins with a "---" divider and has patch
 819  * information (like the output of git-format-patch), and
 820  *
 821  * (2) any trailing comment lines, blank lines like in the output of "git
 822  * commit -v", or stuff below the "cut" (scissor) line.
 823  *
 824  * As a formula, the situation looks like this:
 825  *
 826  *     INPUT = LOG MESSAGE + IGNORED
 827  *
 828  * where IGNORED can be either of the two categories described above. It may be
 829  * that there is nothing to ignore. Now it may be the case that the LOG MESSAGE
 830  * contains a trailer block, but that's not the concern of this function.
 831  */
 832 static size_t find_end_of_log_message(const char *input, int no_divider)
 833 {
 834         size_t end;
 835         const char *s;
 836
 837         /* Assume the naive end of the input is already what we want. */
 838         end = strlen(input);
 839
 840         /* Optionally skip over any patch part ("---" line and below). */
 841         if (!no_divider) {
 842                 for (s = input; *s; s = next_line(s)) {
 843                         const char *v;
 844
 845                         if (skip_prefix(s, "---", &v) && isspace(*v)) {
 846                                 end = s - input;
 847                                 break;
 848                         }
 849                 }
 850         }
 851
 852         /* Skip over other ignorable bits. */
 853         return end - ignored_log_message_bytes(input, end);
 854 }
 855
 856 /*
 857  * Return the position of the first trailer line or len if there are no
 858  * trailers.
 859  */
 860 static size_t find_trailer_block_start(const char *buf, size_t len)
 861 {
 862         const char *s;
 863         ssize_t end_of_title, l;
 864         int only_spaces = 1;
 865         int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 866         /*
 867          * Number of possible continuation lines encountered. This will be
 868          * reset to 0 if we encounter a trailer (since those lines are to be
 869          * considered continuations of that trailer), and added to
 870          * non_trailer_lines if we encounter a non-trailer (since those lines
 871          * are to be considered non-trailers).
 872          */
 873         int possible_continuation_lines = 0;
 874
 875         /* The first paragraph is the title and cannot be trailers */
 876         for (s = buf; s < buf + len; s = next_line(s)) {
 877                 if (s[0] == comment_line_char)
 878                         continue;
 879                 if (is_blank_line(s))
 880                         break;
 881         }
 882         end_of_title = s - buf;
 883
 884         /*
 885          * Get the start of the trailers by looking starting from the end for a
 886          * blank line before a set of non-blank lines that (i) are all
 887          * trailers, or (ii) contains at least one Git-generated trailer and
 888          * consists of at least 25% trailers.
 889          */
 890         for (l = last_line(buf, len);
 891              l >= end_of_title;
 892              l = last_line(buf, l)) {
 893                 const char *bol = buf + l;
 894                 const char **p;
 895                 ssize_t separator_pos;
 896
 897                 if (bol[0] == comment_line_char) {
 898                         non_trailer_lines += possible_continuation_lines;
 899                         possible_continuation_lines = 0;
 900                         continue;
 901                 }
 902                 if (is_blank_line(bol)) {
 903                         if (only_spaces)
 904                                 continue;
 905                         non_trailer_lines += possible_continuation_lines;
 906                         if (recognized_prefix &&
 907                             trailer_lines * 3 >= non_trailer_lines)
 908                                 return next_line(bol) - buf;
 909                         else if (trailer_lines && !non_trailer_lines)
 910                                 return next_line(bol) - buf;
 911                         return len;
 912                 }
 913                 only_spaces = 0;
 914
 915                 for (p = git_generated_prefixes; *p; p++) {
 916                         if (starts_with(bol, *p)) {
 917                                 trailer_lines++;
 918                                 possible_continuation_lines = 0;
 919                                 recognized_prefix = 1;
 920                                 goto continue_outer_loop;
 921                         }
 922                 }
 923
 924                 separator_pos = find_separator(bol, separators);
 925                 if (separator_pos >= 1 && !isspace(bol[0])) {
 926                         struct list_head *pos;
 927
 928                         trailer_lines++;
 929                         possible_continuation_lines = 0;
 930                         if (recognized_prefix)
 931                                 continue;
 932                         list_for_each(pos, &conf_head) {
 933                                 struct arg_item *item;
 934                                 item = list_entry(pos, struct arg_item, list);
 935                                 if (token_matches_item(bol, item,
 936                                                        separator_pos)) {
 937                                         recognized_prefix = 1;
 938                                         break;
 939                                 }
 940                         }
 941                 } else if (isspace(bol[0]))
 942                         possible_continuation_lines++;
 943                 else {
 944                         non_trailer_lines++;
 945                         non_trailer_lines += possible_continuation_lines;
 946                         possible_continuation_lines = 0;
 947                 }
 948 continue_outer_loop:
 949                 ;
 950         }
 951
 952         return len;
 953 }
 954
 955 static int ends_with_blank_line(const char *buf, size_t len)
 956 {
 957         ssize_t ll = last_line(buf, len);
 958         if (ll < 0)
 959                 return 0;
 960         return is_blank_line(buf + ll);
 961 }
 962
 963 static void unfold_value(struct strbuf *val)
 964 {
 965         struct strbuf out = STRBUF_INIT;
 966         size_t i;
 967
 968         strbuf_grow(&out, val->len);
 969         i = 0;
 970         while (i < val->len) {
 971                 char c = val->buf[i++];
 972                 if (c == '\n') {
 973                         /* Collapse continuation down to a single space. */
 974                         while (i < val->len && isspace(val->buf[i]))
 975                                 i++;
 976                         strbuf_addch(&out, ' ');
 977                 } else {
 978                         strbuf_addch(&out, c);
 979                 }
 980         }
 981
 982         /* Empty lines may have left us with whitespace cruft at the edges */
 983         strbuf_trim(&out);
 984
 985         /* output goes back to val as if we modified it in-place */
 986         strbuf_swap(&out, val);
 987         strbuf_release(&out);
 988 }
 989
 990 /*
 991  * Parse trailers in "str", populating the trailer info and "head"
 992  * linked list structure.
 993  */
 994 static void parse_trailers(struct trailer_info *info,
 995                              const char *str,
 996                              struct list_head *head,
 997                              const struct process_trailer_options *opts)
 998 {
 999         struct strbuf tok = STRBUF_INIT;
1000         struct strbuf val = STRBUF_INIT;
1001         size_t i;
1002
1003         trailer_info_get(info, str, opts);
1004
1005         for (i = 0; i < info->trailer_nr; i++) {
1006                 int separator_pos;
1007                 char *trailer = info->trailers[i];
1008                 if (trailer[0] == comment_line_char)
1009                         continue;
1010                 separator_pos = find_separator(trailer, separators);
1011                 if (separator_pos >= 1) {
1012                         parse_trailer(&tok, &val, NULL, trailer,
1013                                       separator_pos);
1014                         if (opts->unfold)
1015                                 unfold_value(&val);
1016                         add_trailer_item(head,
1017                                          strbuf_detach(&tok, NULL),
1018                                          strbuf_detach(&val, NULL));
1019                 } else if (!opts->only_trailers) {
1020                         strbuf_addstr(&val, trailer);
1021                         strbuf_strip_suffix(&val, "\n");
1022                         add_trailer_item(head,
1023                                          NULL,
1024                                          strbuf_detach(&val, NULL));
1025                 }
1026         }
1027 }
1028
1029 static void free_all(struct list_head *head)
1030 {
1031         struct list_head *pos, *p;
1032         list_for_each_safe(pos, p, head) {
1033                 list_del(pos);
1034                 free_trailer_item(list_entry(pos, struct trailer_item, list));
1035         }
1036 }
1037
1038 static struct tempfile *trailers_tempfile;
1039
1040 static FILE *create_in_place_tempfile(const char *file)
1041 {
1042         struct stat st;
1043         struct strbuf filename_template = STRBUF_INIT;
1044         const char *tail;
1045         FILE *outfile;
1046
1047         if (stat(file, &st))
1048                 die_errno(_("could not stat %s"), file);
1049         if (!S_ISREG(st.st_mode))
1050                 die(_("file %s is not a regular file"), file);
1051         if (!(st.st_mode & S_IWUSR))
1052                 die(_("file %s is not writable by user"), file);
1053
1054         /* Create temporary file in the same directory as the original */
1055         tail = strrchr(file, '/');
1056         if (tail)
1057                 strbuf_add(&filename_template, file, tail - file + 1);
1058         strbuf_addstr(&filename_template, "git-interpret-trailers-XXXXXX");
1059
1060         trailers_tempfile = xmks_tempfile_m(filename_template.buf, st.st_mode);
1061         strbuf_release(&filename_template);
1062         outfile = fdopen_tempfile(trailers_tempfile, "w");
1063         if (!outfile)
1064                 die_errno(_("could not open temporary file"));
1065
1066         return outfile;
1067 }
1068
1069 void process_trailers(const char *file,
1070                       const struct process_trailer_options *opts,
1071                       struct list_head *new_trailer_head)
1072 {
1073         LIST_HEAD(head);
1074         struct strbuf sb = STRBUF_INIT;
1075         struct trailer_info info;
1076         FILE *outfile = stdout;
1077
1078         ensure_configured();
1079
1080         read_input_file(&sb, file);
1081
1082         if (opts->in_place)
1083                 outfile = create_in_place_tempfile(file);
1084
1085         parse_trailers(&info, sb.buf, &head, opts);
1086
1087         /* Print the lines before the trailers */
1088         if (!opts->only_trailers)
1089                 fwrite(sb.buf, 1, info.trailer_block_start, outfile);
1090
1091         if (!opts->only_trailers && !info.blank_line_before_trailer)
1092                 fprintf(outfile, "\n");
1093
1094
1095         if (!opts->only_input) {
1096                 LIST_HEAD(config_head);
1097                 LIST_HEAD(arg_head);
1098                 parse_trailers_from_config(&config_head);
1099                 parse_trailers_from_command_line_args(&arg_head, new_trailer_head);
1100                 list_splice(&config_head, &arg_head);
1101                 process_trailers_lists(&head, &arg_head);
1102         }
1103
1104         print_all(outfile, &head, opts);
1105
1106         free_all(&head);
1107         trailer_info_release(&info);
1108
1109         /* Print the lines after the trailers as is */
1110         if (!opts->only_trailers)
1111                 fwrite(sb.buf + info.trailer_block_end, 1, sb.len - info.trailer_block_end, outfile);
1112
1113         if (opts->in_place)
1114                 if (rename_tempfile(&trailers_tempfile, file))
1115                         die_errno(_("could not rename temporary file to %s"), file);
1116
1117         strbuf_release(&sb);
1118 }
1119
1120 void trailer_info_get(struct trailer_info *info, const char *str,
1121                       const struct process_trailer_options *opts)
1122 {
1123         size_t end_of_log_message = 0, trailer_block_start = 0;
1124         struct strbuf **trailer_lines, **ptr;
1125         char **trailer_strings = NULL;
1126         size_t nr = 0, alloc = 0;
1127         char **last = NULL;
1128
1129         ensure_configured();
1130
1131         end_of_log_message = find_end_of_log_message(str, opts->no_divider);
1132         trailer_block_start = find_trailer_block_start(str, end_of_log_message);
1133
1134         trailer_lines = strbuf_split_buf(str + trailer_block_start,
1135                                          end_of_log_message - trailer_block_start,
1136                                          '\n',
1137                                          0);
1138         for (ptr = trailer_lines; *ptr; ptr++) {
1139                 if (last && isspace((*ptr)->buf[0])) {
1140                         struct strbuf sb = STRBUF_INIT;
1141                         strbuf_attach(&sb, *last, strlen(*last), strlen(*last));
1142                         strbuf_addbuf(&sb, *ptr);
1143                         *last = strbuf_detach(&sb, NULL);
1144                         continue;
1145                 }
1146                 ALLOC_GROW(trailer_strings, nr + 1, alloc);
1147                 trailer_strings[nr] = strbuf_detach(*ptr, NULL);
1148                 last = find_separator(trailer_strings[nr], separators) >= 1
1149                         ? &trailer_strings[nr]
1150                         : NULL;
1151                 nr++;
1152         }
1153         strbuf_list_free(trailer_lines);
1154
1155         info->blank_line_before_trailer = ends_with_blank_line(str,
1156                                                                trailer_block_start);
1157         info->trailer_block_start = trailer_block_start;
1158         info->trailer_block_end = end_of_log_message;
1159         info->trailers = trailer_strings;
1160         info->trailer_nr = nr;
1161 }
1162
1163 void trailer_info_release(struct trailer_info *info)
1164 {
1165         size_t i;
1166         for (i = 0; i < info->trailer_nr; i++)
1167                 free(info->trailers[i]);
1168         free(info->trailers);
1169 }
1170
1171 static void format_trailer_info(struct strbuf *out,
1172                                 const struct trailer_info *info,
1173                                 const char *msg,
1174                                 const struct process_trailer_options *opts)
1175 {
1176         size_t origlen = out->len;
1177         size_t i;
1178
1179         /* If we want the whole block untouched, we can take the fast path. */
1180         if (!opts->only_trailers && !opts->unfold && !opts->filter &&
1181             !opts->separator && !opts->key_only && !opts->value_only &&
1182             !opts->key_value_separator) {
1183                 strbuf_add(out, msg + info->trailer_block_start,
1184                            info->trailer_block_end - info->trailer_block_start);
1185                 return;
1186         }
1187
1188         for (i = 0; i < info->trailer_nr; i++) {
1189                 char *trailer = info->trailers[i];
1190                 ssize_t separator_pos = find_separator(trailer, separators);
1191
1192                 if (separator_pos >= 1) {
1193                         struct strbuf tok = STRBUF_INIT;
1194                         struct strbuf val = STRBUF_INIT;
1195
1196                         parse_trailer(&tok, &val, NULL, trailer, separator_pos);
1197                         if (!opts->filter || opts->filter(&tok, opts->filter_data)) {
1198                                 if (opts->unfold)
1199                                         unfold_value(&val);
1200
1201                                 if (opts->separator && out->len != origlen)
1202                                         strbuf_addbuf(out, opts->separator);
1203                                 if (!opts->value_only)
1204                                         strbuf_addbuf(out, &tok);
1205                                 if (!opts->key_only && !opts->value_only) {
1206                                         if (opts->key_value_separator)
1207                                                 strbuf_addbuf(out, opts->key_value_separator);
1208                                         else
1209                                                 strbuf_addstr(out, ": ");
1210                                 }
1211                                 if (!opts->key_only)
1212                                         strbuf_addbuf(out, &val);
1213                                 if (!opts->separator)
1214                                         strbuf_addch(out, '\n');
1215                         }
1216                         strbuf_release(&tok);
1217                         strbuf_release(&val);
1218
1219                 } else if (!opts->only_trailers) {
1220                         if (opts->separator && out->len != origlen) {
1221                                 strbuf_addbuf(out, opts->separator);
1222                         }
1223                         strbuf_addstr(out, trailer);
1224                         if (opts->separator) {
1225                                 strbuf_rtrim(out);
1226                         }
1227                 }
1228         }
1229
1230 }
1231
1232 void format_trailers_from_commit(struct strbuf *out, const char *msg,
1233                                  const struct process_trailer_options *opts)
1234 {
1235         struct trailer_info info;
1236
1237         trailer_info_get(&info, msg, opts);
1238         format_trailer_info(out, &info, msg, opts);
1239         trailer_info_release(&info);
1240 }
1241
1242 void trailer_iterator_init(struct trailer_iterator *iter, const char *msg)
1243 {
1244         struct process_trailer_options opts = PROCESS_TRAILER_OPTIONS_INIT;
1245         strbuf_init(&iter->key, 0);
1246         strbuf_init(&iter->val, 0);
1247         opts.no_divider = 1;
1248         trailer_info_get(&iter->internal.info, msg, &opts);
1249         iter->internal.cur = 0;
1250 }
1251
1252 int trailer_iterator_advance(struct trailer_iterator *iter)
1253 {
1254         while (iter->internal.cur < iter->internal.info.trailer_nr) {
1255                 char *trailer = iter->internal.info.trailers[iter->internal.cur++];
1256                 int separator_pos = find_separator(trailer, separators);
1257
1258                 if (separator_pos < 1)
1259                         continue; /* not a real trailer */
1260
1261                 strbuf_reset(&iter->key);
1262                 strbuf_reset(&iter->val);
1263                 parse_trailer(&iter->key, &iter->val, NULL,
1264                               trailer, separator_pos);
1265                 unfold_value(&iter->val);
1266                 return 1;
1267         }
1268         return 0;
1269 }
1270
1271 void trailer_iterator_release(struct trailer_iterator *iter)
1272 {
1273         trailer_info_release(&iter->internal.info);
1274         strbuf_release(&iter->val);
1275         strbuf_release(&iter->key);
1276 }