Andrew's git - gitweb.git/blob

   1#include "cache.h"
   2#include "string-list.h"
   3#include "run-command.h"
   4#include "string-list.h"
   5#include "commit.h"
   6#include "trailer.h"
   7/*
   8 * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
   9 */
  10
  11enum action_where { WHERE_END, WHERE_AFTER, WHERE_BEFORE, WHERE_START };
  12enum action_if_exists { EXISTS_ADD_IF_DIFFERENT_NEIGHBOR, EXISTS_ADD_IF_DIFFERENT,
  13                        EXISTS_ADD, EXISTS_REPLACE, EXISTS_DO_NOTHING };
  14enum action_if_missing { MISSING_ADD, MISSING_DO_NOTHING };
  15
  16struct conf_info {
  17        char *name;
  18        char *key;
  19        char *command;
  20        enum action_where where;
  21        enum action_if_exists if_exists;
  22        enum action_if_missing if_missing;
  23};
  24
  25static struct conf_info default_conf_info;
  26
  27struct trailer_item {
  28        struct trailer_item *previous;
  29        struct trailer_item *next;
  30        const char *token;
  31        const char *value;
  32        struct conf_info conf;
  33};
  34
  35static struct trailer_item *first_conf_item;
  36
  37static char *separators = ":";
  38
  39#define TRAILER_ARG_STRING "$ARG"
  40
  41static int after_or_end(enum action_where where)
  42{
  43        return (where == WHERE_AFTER) || (where == WHERE_END);
  44}
  45
  46/*
  47 * Return the length of the string not including any final
  48 * punctuation. E.g., the input "Signed-off-by:" would return
  49 * 13, stripping the trailing punctuation but retaining
  50 * internal punctuation.
  51 */
  52static size_t token_len_without_separator(const char *token, size_t len)
  53{
  54        while (len > 0 && !isalnum(token[len - 1]))
  55                len--;
  56        return len;
  57}
  58
  59static int same_token(struct trailer_item *a, struct trailer_item *b)
  60{
  61        size_t a_len = token_len_without_separator(a->token, strlen(a->token));
  62        size_t b_len = token_len_without_separator(b->token, strlen(b->token));
  63        size_t min_len = (a_len > b_len) ? b_len : a_len;
  64
  65        return !strncasecmp(a->token, b->token, min_len);
  66}
  67
  68static int same_value(struct trailer_item *a, struct trailer_item *b)
  69{
  70        return !strcasecmp(a->value, b->value);
  71}
  72
  73static int same_trailer(struct trailer_item *a, struct trailer_item *b)
  74{
  75        return same_token(a, b) && same_value(a, b);
  76}
  77
  78static inline int contains_only_spaces(const char *str)
  79{
  80        const char *s = str;
  81        while (*s && isspace(*s))
  82                s++;
  83        return !*s;
  84}
  85
  86static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
  87{
  88        const char *ptr = strstr(sb->buf, a);
  89        if (ptr)
  90                strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
  91}
  92
  93static void free_trailer_item(struct trailer_item *item)
  94{
  95        free(item->conf.name);
  96        free(item->conf.key);
  97        free(item->conf.command);
  98        free((char *)item->token);
  99        free((char *)item->value);
 100        free(item);
 101}
 102
 103static char last_non_space_char(const char *s)
 104{
 105        int i;
 106        for (i = strlen(s) - 1; i >= 0; i--)
 107                if (!isspace(s[i]))
 108                        return s[i];
 109        return '\0';
 110}
 111
 112static void print_tok_val(const char *tok, const char *val)
 113{
 114        char c = last_non_space_char(tok);
 115        if (!c)
 116                return;
 117        if (strchr(separators, c))
 118                printf("%s%s\n", tok, val);
 119        else
 120                printf("%s%c %s\n", tok, separators[0], val);
 121}
 122
 123static void print_all(struct trailer_item *first, int trim_empty)
 124{
 125        struct trailer_item *item;
 126        for (item = first; item; item = item->next) {
 127                if (!trim_empty || strlen(item->value) > 0)
 128                        print_tok_val(item->token, item->value);
 129        }
 130}
 131
 132static void update_last(struct trailer_item **last)
 133{
 134        if (*last)
 135                while ((*last)->next != NULL)
 136                        *last = (*last)->next;
 137}
 138
 139static void update_first(struct trailer_item **first)
 140{
 141        if (*first)
 142                while ((*first)->previous != NULL)
 143                        *first = (*first)->previous;
 144}
 145
 146static void add_arg_to_input_list(struct trailer_item *on_tok,
 147                                  struct trailer_item *arg_tok,
 148                                  struct trailer_item **first,
 149                                  struct trailer_item **last)
 150{
 151        if (after_or_end(arg_tok->conf.where)) {
 152                arg_tok->next = on_tok->next;
 153                on_tok->next = arg_tok;
 154                arg_tok->previous = on_tok;
 155                if (arg_tok->next)
 156                        arg_tok->next->previous = arg_tok;
 157                update_last(last);
 158        } else {
 159                arg_tok->previous = on_tok->previous;
 160                on_tok->previous = arg_tok;
 161                arg_tok->next = on_tok;
 162                if (arg_tok->previous)
 163                        arg_tok->previous->next = arg_tok;
 164                update_first(first);
 165        }
 166}
 167
 168static int check_if_different(struct trailer_item *in_tok,
 169                              struct trailer_item *arg_tok,
 170                              int check_all)
 171{
 172        enum action_where where = arg_tok->conf.where;
 173        do {
 174                if (!in_tok)
 175                        return 1;
 176                if (same_trailer(in_tok, arg_tok))
 177                        return 0;
 178                /*
 179                 * if we want to add a trailer after another one,
 180                 * we have to check those before this one
 181                 */
 182                in_tok = after_or_end(where) ? in_tok->previous : in_tok->next;
 183        } while (check_all);
 184        return 1;
 185}
 186
 187static void remove_from_list(struct trailer_item *item,
 188                             struct trailer_item **first,
 189                             struct trailer_item **last)
 190{
 191        struct trailer_item *next = item->next;
 192        struct trailer_item *previous = item->previous;
 193
 194        if (next) {
 195                item->next->previous = previous;
 196                item->next = NULL;
 197        } else if (last)
 198                *last = previous;
 199
 200        if (previous) {
 201                item->previous->next = next;
 202                item->previous = NULL;
 203        } else if (first)
 204                *first = next;
 205}
 206
 207static struct trailer_item *remove_first(struct trailer_item **first)
 208{
 209        struct trailer_item *item = *first;
 210        *first = item->next;
 211        if (item->next) {
 212                item->next->previous = NULL;
 213                item->next = NULL;
 214        }
 215        return item;
 216}
 217
 218static int read_from_command(struct child_process *cp, struct strbuf *buf)
 219{
 220        if (run_command(cp))
 221                return error("running trailer command '%s' failed", cp->argv[0]);
 222        if (strbuf_read(buf, cp->out, 1024) < 1)
 223                return error("reading from trailer command '%s' failed", cp->argv[0]);
 224        strbuf_trim(buf);
 225        return 0;
 226}
 227
 228static const char *apply_command(const char *command, const char *arg)
 229{
 230        struct strbuf cmd = STRBUF_INIT;
 231        struct strbuf buf = STRBUF_INIT;
 232        struct child_process cp = CHILD_PROCESS_INIT;
 233        const char *argv[] = {NULL, NULL};
 234        const char *result;
 235
 236        strbuf_addstr(&cmd, command);
 237        if (arg)
 238                strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 239
 240        argv[0] = cmd.buf;
 241        cp.argv = argv;
 242        cp.env = local_repo_env;
 243        cp.no_stdin = 1;
 244        cp.out = -1;
 245        cp.use_shell = 1;
 246
 247        if (read_from_command(&cp, &buf)) {
 248                strbuf_release(&buf);
 249                result = xstrdup("");
 250        } else
 251                result = strbuf_detach(&buf, NULL);
 252
 253        strbuf_release(&cmd);
 254        return result;
 255}
 256
 257static void apply_item_command(struct trailer_item *in_tok, struct trailer_item *arg_tok)
 258{
 259        if (arg_tok->conf.command) {
 260                const char *arg;
 261                if (arg_tok->value && arg_tok->value[0]) {
 262                        arg = arg_tok->value;
 263                } else {
 264                        if (in_tok && in_tok->value)
 265                                arg = xstrdup(in_tok->value);
 266                        else
 267                                arg = xstrdup("");
 268                }
 269                arg_tok->value = apply_command(arg_tok->conf.command, arg);
 270                free((char *)arg);
 271        }
 272}
 273
 274static void apply_arg_if_exists(struct trailer_item *in_tok,
 275                                struct trailer_item *arg_tok,
 276                                struct trailer_item *on_tok,
 277                                struct trailer_item **in_tok_first,
 278                                struct trailer_item **in_tok_last)
 279{
 280        switch (arg_tok->conf.if_exists) {
 281        case EXISTS_DO_NOTHING:
 282                free_trailer_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                                      in_tok_first, in_tok_last);
 288                remove_from_list(in_tok, in_tok_first, in_tok_last);
 289                free_trailer_item(in_tok);
 290                break;
 291        case EXISTS_ADD:
 292                apply_item_command(in_tok, arg_tok);
 293                add_arg_to_input_list(on_tok, arg_tok,
 294                                      in_tok_first, in_tok_last);
 295                break;
 296        case EXISTS_ADD_IF_DIFFERENT:
 297                apply_item_command(in_tok, arg_tok);
 298                if (check_if_different(in_tok, arg_tok, 1))
 299                        add_arg_to_input_list(on_tok, arg_tok,
 300                                              in_tok_first, in_tok_last);
 301                else
 302                        free_trailer_item(arg_tok);
 303                break;
 304        case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 305                apply_item_command(in_tok, arg_tok);
 306                if (check_if_different(on_tok, arg_tok, 0))
 307                        add_arg_to_input_list(on_tok, arg_tok,
 308                                              in_tok_first, in_tok_last);
 309                else
 310                        free_trailer_item(arg_tok);
 311                break;
 312        }
 313}
 314
 315static void apply_arg_if_missing(struct trailer_item **in_tok_first,
 316                                 struct trailer_item **in_tok_last,
 317                                 struct trailer_item *arg_tok)
 318{
 319        struct trailer_item **in_tok;
 320        enum action_where where;
 321
 322        switch (arg_tok->conf.if_missing) {
 323        case MISSING_DO_NOTHING:
 324                free_trailer_item(arg_tok);
 325                break;
 326        case MISSING_ADD:
 327                where = arg_tok->conf.where;
 328                in_tok = after_or_end(where) ? in_tok_last : in_tok_first;
 329                apply_item_command(NULL, arg_tok);
 330                if (*in_tok) {
 331                        add_arg_to_input_list(*in_tok, arg_tok,
 332                                              in_tok_first, in_tok_last);
 333                } else {
 334                        *in_tok_first = arg_tok;
 335                        *in_tok_last = arg_tok;
 336                }
 337                break;
 338        }
 339}
 340
 341static int find_same_and_apply_arg(struct trailer_item **in_tok_first,
 342                                   struct trailer_item **in_tok_last,
 343                                   struct trailer_item *arg_tok)
 344{
 345        struct trailer_item *in_tok;
 346        struct trailer_item *on_tok;
 347        struct trailer_item *following_tok;
 348
 349        enum action_where where = arg_tok->conf.where;
 350        int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 351        int backwards = after_or_end(where);
 352        struct trailer_item *start_tok = backwards ? *in_tok_last : *in_tok_first;
 353
 354        for (in_tok = start_tok; in_tok; in_tok = following_tok) {
 355                following_tok = backwards ? in_tok->previous : in_tok->next;
 356                if (!same_token(in_tok, arg_tok))
 357                        continue;
 358                on_tok = middle ? in_tok : start_tok;
 359                apply_arg_if_exists(in_tok, arg_tok, on_tok,
 360                                    in_tok_first, in_tok_last);
 361                return 1;
 362        }
 363        return 0;
 364}
 365
 366static void process_trailers_lists(struct trailer_item **in_tok_first,
 367                                   struct trailer_item **in_tok_last,
 368                                   struct trailer_item **arg_tok_first)
 369{
 370        struct trailer_item *arg_tok;
 371        struct trailer_item *next_arg;
 372
 373        if (!*arg_tok_first)
 374                return;
 375
 376        for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
 377                int applied = 0;
 378
 379                next_arg = arg_tok->next;
 380                remove_from_list(arg_tok, arg_tok_first, NULL);
 381
 382                applied = find_same_and_apply_arg(in_tok_first,
 383                                                  in_tok_last,
 384                                                  arg_tok);
 385
 386                if (!applied)
 387                        apply_arg_if_missing(in_tok_first,
 388                                             in_tok_last,
 389                                             arg_tok);
 390        }
 391}
 392
 393static int set_where(struct conf_info *item, const char *value)
 394{
 395        if (!strcasecmp("after", value))
 396                item->where = WHERE_AFTER;
 397        else if (!strcasecmp("before", value))
 398                item->where = WHERE_BEFORE;
 399        else if (!strcasecmp("end", value))
 400                item->where = WHERE_END;
 401        else if (!strcasecmp("start", value))
 402                item->where = WHERE_START;
 403        else
 404                return -1;
 405        return 0;
 406}
 407
 408static int set_if_exists(struct conf_info *item, const char *value)
 409{
 410        if (!strcasecmp("addIfDifferent", value))
 411                item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 412        else if (!strcasecmp("addIfDifferentNeighbor", value))
 413                item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 414        else if (!strcasecmp("add", value))
 415                item->if_exists = EXISTS_ADD;
 416        else if (!strcasecmp("replace", value))
 417                item->if_exists = EXISTS_REPLACE;
 418        else if (!strcasecmp("doNothing", value))
 419                item->if_exists = EXISTS_DO_NOTHING;
 420        else
 421                return -1;
 422        return 0;
 423}
 424
 425static int set_if_missing(struct conf_info *item, const char *value)
 426{
 427        if (!strcasecmp("doNothing", value))
 428                item->if_missing = MISSING_DO_NOTHING;
 429        else if (!strcasecmp("add", value))
 430                item->if_missing = MISSING_ADD;
 431        else
 432                return -1;
 433        return 0;
 434}
 435
 436static void duplicate_conf(struct conf_info *dst, struct conf_info *src)
 437{
 438        *dst = *src;
 439        if (src->name)
 440                dst->name = xstrdup(src->name);
 441        if (src->key)
 442                dst->key = xstrdup(src->key);
 443        if (src->command)
 444                dst->command = xstrdup(src->command);
 445}
 446
 447static struct trailer_item *get_conf_item(const char *name)
 448{
 449        struct trailer_item *item;
 450        struct trailer_item *previous;
 451
 452        /* Look up item with same name */
 453        for (previous = NULL, item = first_conf_item;
 454             item;
 455             previous = item, item = item->next) {
 456                if (!strcasecmp(item->conf.name, name))
 457                        return item;
 458        }
 459
 460        /* Item does not already exists, create it */
 461        item = xcalloc(sizeof(struct trailer_item), 1);
 462        duplicate_conf(&item->conf, &default_conf_info);
 463        item->conf.name = xstrdup(name);
 464
 465        if (!previous)
 466                first_conf_item = item;
 467        else {
 468                previous->next = item;
 469                item->previous = previous;
 470        }
 471
 472        return item;
 473}
 474
 475enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 476                         TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 477
 478static struct {
 479        const char *name;
 480        enum trailer_info_type type;
 481} trailer_config_items[] = {
 482        { "key", TRAILER_KEY },
 483        { "command", TRAILER_COMMAND },
 484        { "where", TRAILER_WHERE },
 485        { "ifexists", TRAILER_IF_EXISTS },
 486        { "ifmissing", TRAILER_IF_MISSING }
 487};
 488
 489static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 490{
 491        const char *trailer_item, *variable_name;
 492
 493        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 494                return 0;
 495
 496        variable_name = strrchr(trailer_item, '.');
 497        if (!variable_name) {
 498                if (!strcmp(trailer_item, "where")) {
 499                        if (set_where(&default_conf_info, value) < 0)
 500                                warning(_("unknown value '%s' for key '%s'"),
 501                                        value, conf_key);
 502                } else if (!strcmp(trailer_item, "ifexists")) {
 503                        if (set_if_exists(&default_conf_info, value) < 0)
 504                                warning(_("unknown value '%s' for key '%s'"),
 505                                        value, conf_key);
 506                } else if (!strcmp(trailer_item, "ifmissing")) {
 507                        if (set_if_missing(&default_conf_info, value) < 0)
 508                                warning(_("unknown value '%s' for key '%s'"),
 509                                        value, conf_key);
 510                } else if (!strcmp(trailer_item, "separators")) {
 511                        separators = xstrdup(value);
 512                }
 513        }
 514        return 0;
 515}
 516
 517static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 518{
 519        const char *trailer_item, *variable_name;
 520        struct trailer_item *item;
 521        struct conf_info *conf;
 522        char *name = NULL;
 523        enum trailer_info_type type;
 524        int i;
 525
 526        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 527                return 0;
 528
 529        variable_name = strrchr(trailer_item, '.');
 530        if (!variable_name)
 531                return 0;
 532
 533        variable_name++;
 534        for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 535                if (strcmp(trailer_config_items[i].name, variable_name))
 536                        continue;
 537                name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 538                type = trailer_config_items[i].type;
 539                break;
 540        }
 541
 542        if (!name)
 543                return 0;
 544
 545        item = get_conf_item(name);
 546        conf = &item->conf;
 547        free(name);
 548
 549        switch (type) {
 550        case TRAILER_KEY:
 551                if (conf->key)
 552                        warning(_("more than one %s"), conf_key);
 553                conf->key = xstrdup(value);
 554                break;
 555        case TRAILER_COMMAND:
 556                if (conf->command)
 557                        warning(_("more than one %s"), conf_key);
 558                conf->command = xstrdup(value);
 559                break;
 560        case TRAILER_WHERE:
 561                if (set_where(conf, value))
 562                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 563                break;
 564        case TRAILER_IF_EXISTS:
 565                if (set_if_exists(conf, value))
 566                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 567                break;
 568        case TRAILER_IF_MISSING:
 569                if (set_if_missing(conf, value))
 570                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 571                break;
 572        default:
 573                die("internal bug in trailer.c");
 574        }
 575        return 0;
 576}
 577
 578static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
 579{
 580        size_t len;
 581        struct strbuf seps = STRBUF_INIT;
 582        strbuf_addstr(&seps, separators);
 583        strbuf_addch(&seps, '=');
 584        len = strcspn(trailer, seps.buf);
 585        strbuf_release(&seps);
 586        if (len == 0) {
 587                int l = strlen(trailer);
 588                while (l > 0 && isspace(trailer[l - 1]))
 589                        l--;
 590                return error(_("empty trailer token in trailer '%.*s'"), l, trailer);
 591        }
 592        if (len < strlen(trailer)) {
 593                strbuf_add(tok, trailer, len);
 594                strbuf_trim(tok);
 595                strbuf_addstr(val, trailer + len + 1);
 596                strbuf_trim(val);
 597        } else {
 598                strbuf_addstr(tok, trailer);
 599                strbuf_trim(tok);
 600        }
 601        return 0;
 602}
 603
 604static const char *token_from_item(struct trailer_item *item, char *tok)
 605{
 606        if (item->conf.key)
 607                return item->conf.key;
 608        if (tok)
 609                return tok;
 610        return item->conf.name;
 611}
 612
 613static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
 614                                             char *tok, char *val)
 615{
 616        struct trailer_item *new = xcalloc(sizeof(*new), 1);
 617        new->value = val ? val : xstrdup("");
 618
 619        if (conf_item) {
 620                duplicate_conf(&new->conf, &conf_item->conf);
 621                new->token = xstrdup(token_from_item(conf_item, tok));
 622                free(tok);
 623        } else {
 624                duplicate_conf(&new->conf, &default_conf_info);
 625                new->token = tok;
 626        }
 627
 628        return new;
 629}
 630
 631static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
 632{
 633        if (!strncasecmp(tok, item->conf.name, tok_len))
 634                return 1;
 635        return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 636}
 637
 638static struct trailer_item *create_trailer_item(const char *string)
 639{
 640        struct strbuf tok = STRBUF_INIT;
 641        struct strbuf val = STRBUF_INIT;
 642        struct trailer_item *item;
 643        int tok_len;
 644
 645        if (parse_trailer(&tok, &val, string))
 646                return NULL;
 647
 648        tok_len = token_len_without_separator(tok.buf, tok.len);
 649
 650        /* Lookup if the token matches something in the config */
 651        for (item = first_conf_item; item; item = item->next) {
 652                if (token_matches_item(tok.buf, item, tok_len))
 653                        return new_trailer_item(item,
 654                                                strbuf_detach(&tok, NULL),
 655                                                strbuf_detach(&val, NULL));
 656        }
 657
 658        return new_trailer_item(NULL,
 659                                strbuf_detach(&tok, NULL),
 660                                strbuf_detach(&val, NULL));
 661}
 662
 663static void add_trailer_item(struct trailer_item **first,
 664                             struct trailer_item **last,
 665                             struct trailer_item *new)
 666{
 667        if (!new)
 668                return;
 669        if (!*last) {
 670                *first = new;
 671                *last = new;
 672        } else {
 673                (*last)->next = new;
 674                new->previous = *last;
 675                *last = new;
 676        }
 677}
 678
 679static struct trailer_item *process_command_line_args(struct string_list *trailers)
 680{
 681        struct trailer_item *arg_tok_first = NULL;
 682        struct trailer_item *arg_tok_last = NULL;
 683        struct string_list_item *tr;
 684        struct trailer_item *item;
 685
 686        /* Add a trailer item for each configured trailer with a command */
 687        for (item = first_conf_item; item; item = item->next) {
 688                if (item->conf.command) {
 689                        struct trailer_item *new = new_trailer_item(item, NULL, NULL);
 690                        add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 691                }
 692        }
 693
 694        /* Add a trailer item for each trailer on the command line */
 695        for_each_string_list_item(tr, trailers) {
 696                struct trailer_item *new = create_trailer_item(tr->string);
 697                add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 698        }
 699
 700        return arg_tok_first;
 701}
 702
 703static struct strbuf **read_input_file(const char *file)
 704{
 705        struct strbuf **lines;
 706        struct strbuf sb = STRBUF_INIT;
 707
 708        if (file) {
 709                if (strbuf_read_file(&sb, file, 0) < 0)
 710                        die_errno(_("could not read input file '%s'"), file);
 711        } else {
 712                if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 713                        die_errno(_("could not read from stdin"));
 714        }
 715
 716        lines = strbuf_split(&sb, '\n');
 717
 718        strbuf_release(&sb);
 719
 720        return lines;
 721}
 722
 723/*
 724 * Return the (0 based) index of the start of the patch or the line
 725 * count if there is no patch in the message.
 726 */
 727static int find_patch_start(struct strbuf **lines, int count)
 728{
 729        int i;
 730
 731        /* Get the start of the patch part if any */
 732        for (i = 0; i < count; i++) {
 733                if (starts_with(lines[i]->buf, "---"))
 734                        return i;
 735        }
 736
 737        return count;
 738}
 739
 740/*
 741 * Return the (0 based) index of the first trailer line or count if
 742 * there are no trailers. Trailers are searched only in the lines from
 743 * index (count - 1) down to index 0.
 744 */
 745static int find_trailer_start(struct strbuf **lines, int count)
 746{
 747        int start, only_spaces = 1;
 748
 749        /*
 750         * Get the start of the trailers by looking starting from the end
 751         * for a line with only spaces before lines with one separator.
 752         */
 753        for (start = count - 1; start >= 0; start--) {
 754                if (lines[start]->buf[0] == comment_line_char)
 755                        continue;
 756                if (contains_only_spaces(lines[start]->buf)) {
 757                        if (only_spaces)
 758                                continue;
 759                        return start + 1;
 760                }
 761                if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 762                        if (only_spaces)
 763                                only_spaces = 0;
 764                        continue;
 765                }
 766                return count;
 767        }
 768
 769        return only_spaces ? count : 0;
 770}
 771
 772/* Get the index of the end of the trailers */
 773static int find_trailer_end(struct strbuf **lines, int patch_start)
 774{
 775        struct strbuf sb = STRBUF_INIT;
 776        int i, ignore_bytes;
 777
 778        for (i = 0; i < patch_start; i++)
 779                strbuf_addbuf(&sb, lines[i]);
 780        ignore_bytes = ignore_non_trailer(&sb);
 781        strbuf_release(&sb);
 782        for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 783                ignore_bytes -= lines[i]->len;
 784
 785        return i + 1;
 786}
 787
 788static int has_blank_line_before(struct strbuf **lines, int start)
 789{
 790        for (;start >= 0; start--) {
 791                if (lines[start]->buf[0] == comment_line_char)
 792                        continue;
 793                return contains_only_spaces(lines[start]->buf);
 794        }
 795        return 0;
 796}
 797
 798static void print_lines(struct strbuf **lines, int start, int end)
 799{
 800        int i;
 801        for (i = start; lines[i] && i < end; i++)
 802                printf("%s", lines[i]->buf);
 803}
 804
 805static int process_input_file(struct strbuf **lines,
 806                              struct trailer_item **in_tok_first,
 807                              struct trailer_item **in_tok_last)
 808{
 809        int count = 0;
 810        int patch_start, trailer_start, trailer_end, i;
 811
 812        /* Get the line count */
 813        while (lines[count])
 814                count++;
 815
 816        patch_start = find_patch_start(lines, count);
 817        trailer_end = find_trailer_end(lines, patch_start);
 818        trailer_start = find_trailer_start(lines, trailer_end);
 819
 820        /* Print lines before the trailers as is */
 821        print_lines(lines, 0, trailer_start);
 822
 823        if (!has_blank_line_before(lines, trailer_start - 1))
 824                printf("\n");
 825
 826        /* Parse trailer lines */
 827        for (i = trailer_start; i < trailer_end; i++) {
 828                if (lines[i]->buf[0] != comment_line_char) {
 829                        struct trailer_item *new = create_trailer_item(lines[i]->buf);
 830                        add_trailer_item(in_tok_first, in_tok_last, new);
 831                }
 832        }
 833
 834        return trailer_end;
 835}
 836
 837static void free_all(struct trailer_item **first)
 838{
 839        while (*first) {
 840                struct trailer_item *item = remove_first(first);
 841                free_trailer_item(item);
 842        }
 843}
 844
 845void process_trailers(const char *file, int trim_empty, struct string_list *trailers)
 846{
 847        struct trailer_item *in_tok_first = NULL;
 848        struct trailer_item *in_tok_last = NULL;
 849        struct trailer_item *arg_tok_first;
 850        struct strbuf **lines;
 851        int trailer_end;
 852
 853        /* Default config must be setup first */
 854        git_config(git_trailer_default_config, NULL);
 855        git_config(git_trailer_config, NULL);
 856
 857        lines = read_input_file(file);
 858
 859        /* Print the lines before the trailers */
 860        trailer_end = process_input_file(lines, &in_tok_first, &in_tok_last);
 861
 862        arg_tok_first = process_command_line_args(trailers);
 863
 864        process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 865
 866        print_all(in_tok_first, trim_empty);
 867
 868        free_all(&in_tok_first);
 869
 870        /* Print the lines after the trailers as is */
 871        print_lines(lines, trailer_end, INT_MAX);
 872
 873        strbuf_list_free(lines);
 874}