Andrew's git / gitweb.git / trailer.c
?
trailer.con commit blame: improve diagnosis for "--reverse NEW" (d993ce1)
   1#include "cache.h"
   2#include "string-list.h"
   3#include "run-command.h"
   4#include "commit.h"
   5#include "tempfile.h"
   6#include "trailer.h"
   7/*
   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(FILE *outfile, 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                fprintf(outfile, "%s%s\n", tok, val);
 119        else
 120                fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 121}
 122
 123static void print_all(FILE *outfile, 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(outfile, 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 const char *apply_command(const char *command, const char *arg)
 219{
 220        struct strbuf cmd = STRBUF_INIT;
 221        struct strbuf buf = STRBUF_INIT;
 222        struct child_process cp = CHILD_PROCESS_INIT;
 223        const char *argv[] = {NULL, NULL};
 224        const char *result;
 225
 226        strbuf_addstr(&cmd, command);
 227        if (arg)
 228                strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 229
 230        argv[0] = cmd.buf;
 231        cp.argv = argv;
 232        cp.env = local_repo_env;
 233        cp.no_stdin = 1;
 234        cp.use_shell = 1;
 235
 236        if (capture_command(&cp, &buf, 1024)) {
 237                error(_("running trailer command '%s' failed"), cmd.buf);
 238                strbuf_release(&buf);
 239                result = xstrdup("");
 240        } else {
 241                strbuf_trim(&buf);
 242                result = strbuf_detach(&buf, NULL);
 243        }
 244
 245        strbuf_release(&cmd);
 246        return result;
 247}
 248
 249static void apply_item_command(struct trailer_item *in_tok, struct trailer_item *arg_tok)
 250{
 251        if (arg_tok->conf.command) {
 252                const char *arg;
 253                if (arg_tok->value && arg_tok->value[0]) {
 254                        arg = arg_tok->value;
 255                } else {
 256                        if (in_tok && in_tok->value)
 257                                arg = xstrdup(in_tok->value);
 258                        else
 259                                arg = xstrdup("");
 260                }
 261                arg_tok->value = apply_command(arg_tok->conf.command, arg);
 262                free((char *)arg);
 263        }
 264}
 265
 266static void apply_arg_if_exists(struct trailer_item *in_tok,
 267                                struct trailer_item *arg_tok,
 268                                struct trailer_item *on_tok,
 269                                struct trailer_item **in_tok_first,
 270                                struct trailer_item **in_tok_last)
 271{
 272        switch (arg_tok->conf.if_exists) {
 273        case EXISTS_DO_NOTHING:
 274                free_trailer_item(arg_tok);
 275                break;
 276        case EXISTS_REPLACE:
 277                apply_item_command(in_tok, arg_tok);
 278                add_arg_to_input_list(on_tok, arg_tok,
 279                                      in_tok_first, in_tok_last);
 280                remove_from_list(in_tok, in_tok_first, in_tok_last);
 281                free_trailer_item(in_tok);
 282                break;
 283        case EXISTS_ADD:
 284                apply_item_command(in_tok, arg_tok);
 285                add_arg_to_input_list(on_tok, arg_tok,
 286                                      in_tok_first, in_tok_last);
 287                break;
 288        case EXISTS_ADD_IF_DIFFERENT:
 289                apply_item_command(in_tok, arg_tok);
 290                if (check_if_different(in_tok, arg_tok, 1))
 291                        add_arg_to_input_list(on_tok, arg_tok,
 292                                              in_tok_first, in_tok_last);
 293                else
 294                        free_trailer_item(arg_tok);
 295                break;
 296        case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 297                apply_item_command(in_tok, arg_tok);
 298                if (check_if_different(on_tok, arg_tok, 0))
 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        }
 305}
 306
 307static void apply_arg_if_missing(struct trailer_item **in_tok_first,
 308                                 struct trailer_item **in_tok_last,
 309                                 struct trailer_item *arg_tok)
 310{
 311        struct trailer_item **in_tok;
 312        enum action_where where;
 313
 314        switch (arg_tok->conf.if_missing) {
 315        case MISSING_DO_NOTHING:
 316                free_trailer_item(arg_tok);
 317                break;
 318        case MISSING_ADD:
 319                where = arg_tok->conf.where;
 320                in_tok = after_or_end(where) ? in_tok_last : in_tok_first;
 321                apply_item_command(NULL, arg_tok);
 322                if (*in_tok) {
 323                        add_arg_to_input_list(*in_tok, arg_tok,
 324                                              in_tok_first, in_tok_last);
 325                } else {
 326                        *in_tok_first = arg_tok;
 327                        *in_tok_last = arg_tok;
 328                }
 329                break;
 330        }
 331}
 332
 333static int find_same_and_apply_arg(struct trailer_item **in_tok_first,
 334                                   struct trailer_item **in_tok_last,
 335                                   struct trailer_item *arg_tok)
 336{
 337        struct trailer_item *in_tok;
 338        struct trailer_item *on_tok;
 339        struct trailer_item *following_tok;
 340
 341        enum action_where where = arg_tok->conf.where;
 342        int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 343        int backwards = after_or_end(where);
 344        struct trailer_item *start_tok = backwards ? *in_tok_last : *in_tok_first;
 345
 346        for (in_tok = start_tok; in_tok; in_tok = following_tok) {
 347                following_tok = backwards ? in_tok->previous : in_tok->next;
 348                if (!same_token(in_tok, arg_tok))
 349                        continue;
 350                on_tok = middle ? in_tok : start_tok;
 351                apply_arg_if_exists(in_tok, arg_tok, on_tok,
 352                                    in_tok_first, in_tok_last);
 353                return 1;
 354        }
 355        return 0;
 356}
 357
 358static void process_trailers_lists(struct trailer_item **in_tok_first,
 359                                   struct trailer_item **in_tok_last,
 360                                   struct trailer_item **arg_tok_first)
 361{
 362        struct trailer_item *arg_tok;
 363        struct trailer_item *next_arg;
 364
 365        if (!*arg_tok_first)
 366                return;
 367
 368        for (arg_tok = *arg_tok_first; arg_tok; arg_tok = next_arg) {
 369                int applied = 0;
 370
 371                next_arg = arg_tok->next;
 372                remove_from_list(arg_tok, arg_tok_first, NULL);
 373
 374                applied = find_same_and_apply_arg(in_tok_first,
 375                                                  in_tok_last,
 376                                                  arg_tok);
 377
 378                if (!applied)
 379                        apply_arg_if_missing(in_tok_first,
 380                                             in_tok_last,
 381                                             arg_tok);
 382        }
 383}
 384
 385static int set_where(struct conf_info *item, const char *value)
 386{
 387        if (!strcasecmp("after", value))
 388                item->where = WHERE_AFTER;
 389        else if (!strcasecmp("before", value))
 390                item->where = WHERE_BEFORE;
 391        else if (!strcasecmp("end", value))
 392                item->where = WHERE_END;
 393        else if (!strcasecmp("start", value))
 394                item->where = WHERE_START;
 395        else
 396                return -1;
 397        return 0;
 398}
 399
 400static int set_if_exists(struct conf_info *item, const char *value)
 401{
 402        if (!strcasecmp("addIfDifferent", value))
 403                item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 404        else if (!strcasecmp("addIfDifferentNeighbor", value))
 405                item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 406        else if (!strcasecmp("add", value))
 407                item->if_exists = EXISTS_ADD;
 408        else if (!strcasecmp("replace", value))
 409                item->if_exists = EXISTS_REPLACE;
 410        else if (!strcasecmp("doNothing", value))
 411                item->if_exists = EXISTS_DO_NOTHING;
 412        else
 413                return -1;
 414        return 0;
 415}
 416
 417static int set_if_missing(struct conf_info *item, const char *value)
 418{
 419        if (!strcasecmp("doNothing", value))
 420                item->if_missing = MISSING_DO_NOTHING;
 421        else if (!strcasecmp("add", value))
 422                item->if_missing = MISSING_ADD;
 423        else
 424                return -1;
 425        return 0;
 426}
 427
 428static void duplicate_conf(struct conf_info *dst, struct conf_info *src)
 429{
 430        *dst = *src;
 431        if (src->name)
 432                dst->name = xstrdup(src->name);
 433        if (src->key)
 434                dst->key = xstrdup(src->key);
 435        if (src->command)
 436                dst->command = xstrdup(src->command);
 437}
 438
 439static struct trailer_item *get_conf_item(const char *name)
 440{
 441        struct trailer_item *item;
 442        struct trailer_item *previous;
 443
 444        /* Look up item with same name */
 445        for (previous = NULL, item = first_conf_item;
 446             item;
 447             previous = item, item = item->next) {
 448                if (!strcasecmp(item->conf.name, name))
 449                        return item;
 450        }
 451
 452        /* Item does not already exists, create it */
 453        item = xcalloc(sizeof(struct trailer_item), 1);
 454        duplicate_conf(&item->conf, &default_conf_info);
 455        item->conf.name = xstrdup(name);
 456
 457        if (!previous)
 458                first_conf_item = item;
 459        else {
 460                previous->next = item;
 461                item->previous = previous;
 462        }
 463
 464        return item;
 465}
 466
 467enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 468                         TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 469
 470static struct {
 471        const char *name;
 472        enum trailer_info_type type;
 473} trailer_config_items[] = {
 474        { "key", TRAILER_KEY },
 475        { "command", TRAILER_COMMAND },
 476        { "where", TRAILER_WHERE },
 477        { "ifexists", TRAILER_IF_EXISTS },
 478        { "ifmissing", TRAILER_IF_MISSING }
 479};
 480
 481static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 482{
 483        const char *trailer_item, *variable_name;
 484
 485        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 486                return 0;
 487
 488        variable_name = strrchr(trailer_item, '.');
 489        if (!variable_name) {
 490                if (!strcmp(trailer_item, "where")) {
 491                        if (set_where(&default_conf_info, value) < 0)
 492                                warning(_("unknown value '%s' for key '%s'"),
 493                                        value, conf_key);
 494                } else if (!strcmp(trailer_item, "ifexists")) {
 495                        if (set_if_exists(&default_conf_info, value) < 0)
 496                                warning(_("unknown value '%s' for key '%s'"),
 497                                        value, conf_key);
 498                } else if (!strcmp(trailer_item, "ifmissing")) {
 499                        if (set_if_missing(&default_conf_info, value) < 0)
 500                                warning(_("unknown value '%s' for key '%s'"),
 501                                        value, conf_key);
 502                } else if (!strcmp(trailer_item, "separators")) {
 503                        separators = xstrdup(value);
 504                }
 505        }
 506        return 0;
 507}
 508
 509static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 510{
 511        const char *trailer_item, *variable_name;
 512        struct trailer_item *item;
 513        struct conf_info *conf;
 514        char *name = NULL;
 515        enum trailer_info_type type;
 516        int i;
 517
 518        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 519                return 0;
 520
 521        variable_name = strrchr(trailer_item, '.');
 522        if (!variable_name)
 523                return 0;
 524
 525        variable_name++;
 526        for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 527                if (strcmp(trailer_config_items[i].name, variable_name))
 528                        continue;
 529                name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 530                type = trailer_config_items[i].type;
 531                break;
 532        }
 533
 534        if (!name)
 535                return 0;
 536
 537        item = get_conf_item(name);
 538        conf = &item->conf;
 539        free(name);
 540
 541        switch (type) {
 542        case TRAILER_KEY:
 543                if (conf->key)
 544                        warning(_("more than one %s"), conf_key);
 545                conf->key = xstrdup(value);
 546                break;
 547        case TRAILER_COMMAND:
 548                if (conf->command)
 549                        warning(_("more than one %s"), conf_key);
 550                conf->command = xstrdup(value);
 551                break;
 552        case TRAILER_WHERE:
 553                if (set_where(conf, value))
 554                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 555                break;
 556        case TRAILER_IF_EXISTS:
 557                if (set_if_exists(conf, value))
 558                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 559                break;
 560        case TRAILER_IF_MISSING:
 561                if (set_if_missing(conf, value))
 562                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 563                break;
 564        default:
 565                die("internal bug in trailer.c");
 566        }
 567        return 0;
 568}
 569
 570static int parse_trailer(struct strbuf *tok, struct strbuf *val, const char *trailer)
 571{
 572        size_t len;
 573        struct strbuf seps = STRBUF_INIT;
 574        strbuf_addstr(&seps, separators);
 575        strbuf_addch(&seps, '=');
 576        len = strcspn(trailer, seps.buf);
 577        strbuf_release(&seps);
 578        if (len == 0) {
 579                int l = strlen(trailer);
 580                while (l > 0 && isspace(trailer[l - 1]))
 581                        l--;
 582                return error(_("empty trailer token in trailer '%.*s'"), l, trailer);
 583        }
 584        if (len < strlen(trailer)) {
 585                strbuf_add(tok, trailer, len);
 586                strbuf_trim(tok);
 587                strbuf_addstr(val, trailer + len + 1);
 588                strbuf_trim(val);
 589        } else {
 590                strbuf_addstr(tok, trailer);
 591                strbuf_trim(tok);
 592        }
 593        return 0;
 594}
 595
 596static const char *token_from_item(struct trailer_item *item, char *tok)
 597{
 598        if (item->conf.key)
 599                return item->conf.key;
 600        if (tok)
 601                return tok;
 602        return item->conf.name;
 603}
 604
 605static struct trailer_item *new_trailer_item(struct trailer_item *conf_item,
 606                                             char *tok, char *val)
 607{
 608        struct trailer_item *new = xcalloc(sizeof(*new), 1);
 609        new->value = val ? val : xstrdup("");
 610
 611        if (conf_item) {
 612                duplicate_conf(&new->conf, &conf_item->conf);
 613                new->token = xstrdup(token_from_item(conf_item, tok));
 614                free(tok);
 615        } else {
 616                duplicate_conf(&new->conf, &default_conf_info);
 617                new->token = tok;
 618        }
 619
 620        return new;
 621}
 622
 623static int token_matches_item(const char *tok, struct trailer_item *item, int tok_len)
 624{
 625        if (!strncasecmp(tok, item->conf.name, tok_len))
 626                return 1;
 627        return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 628}
 629
 630static struct trailer_item *create_trailer_item(const char *string)
 631{
 632        struct strbuf tok = STRBUF_INIT;
 633        struct strbuf val = STRBUF_INIT;
 634        struct trailer_item *item;
 635        int tok_len;
 636
 637        if (parse_trailer(&tok, &val, string))
 638                return NULL;
 639
 640        tok_len = token_len_without_separator(tok.buf, tok.len);
 641
 642        /* Lookup if the token matches something in the config */
 643        for (item = first_conf_item; item; item = item->next) {
 644                if (token_matches_item(tok.buf, item, tok_len))
 645                        return new_trailer_item(item,
 646                                                strbuf_detach(&tok, NULL),
 647                                                strbuf_detach(&val, NULL));
 648        }
 649
 650        return new_trailer_item(NULL,
 651                                strbuf_detach(&tok, NULL),
 652                                strbuf_detach(&val, NULL));
 653}
 654
 655static void add_trailer_item(struct trailer_item **first,
 656                             struct trailer_item **last,
 657                             struct trailer_item *new)
 658{
 659        if (!new)
 660                return;
 661        if (!*last) {
 662                *first = new;
 663                *last = new;
 664        } else {
 665                (*last)->next = new;
 666                new->previous = *last;
 667                *last = new;
 668        }
 669}
 670
 671static struct trailer_item *process_command_line_args(struct string_list *trailers)
 672{
 673        struct trailer_item *arg_tok_first = NULL;
 674        struct trailer_item *arg_tok_last = NULL;
 675        struct string_list_item *tr;
 676        struct trailer_item *item;
 677
 678        /* Add a trailer item for each configured trailer with a command */
 679        for (item = first_conf_item; item; item = item->next) {
 680                if (item->conf.command) {
 681                        struct trailer_item *new = new_trailer_item(item, NULL, NULL);
 682                        add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 683                }
 684        }
 685
 686        /* Add a trailer item for each trailer on the command line */
 687        for_each_string_list_item(tr, trailers) {
 688                struct trailer_item *new = create_trailer_item(tr->string);
 689                add_trailer_item(&arg_tok_first, &arg_tok_last, new);
 690        }
 691
 692        return arg_tok_first;
 693}
 694
 695static struct strbuf **read_input_file(const char *file)
 696{
 697        struct strbuf **lines;
 698        struct strbuf sb = STRBUF_INIT;
 699
 700        if (file) {
 701                if (strbuf_read_file(&sb, file, 0) < 0)
 702                        die_errno(_("could not read input file '%s'"), file);
 703        } else {
 704                if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 705                        die_errno(_("could not read from stdin"));
 706        }
 707
 708        lines = strbuf_split(&sb, '\n');
 709
 710        strbuf_release(&sb);
 711
 712        return lines;
 713}
 714
 715/*
 716 * Return the (0 based) index of the start of the patch or the line
 717 * count if there is no patch in the message.
 718 */
 719static int find_patch_start(struct strbuf **lines, int count)
 720{
 721        int i;
 722
 723        /* Get the start of the patch part if any */
 724        for (i = 0; i < count; i++) {
 725                if (starts_with(lines[i]->buf, "---"))
 726                        return i;
 727        }
 728
 729        return count;
 730}
 731
 732/*
 733 * Return the (0 based) index of the first trailer line or count if
 734 * there are no trailers. Trailers are searched only in the lines from
 735 * index (count - 1) down to index 0.
 736 */
 737static int find_trailer_start(struct strbuf **lines, int count)
 738{
 739        int start, end_of_title, only_spaces = 1;
 740
 741        /* The first paragraph is the title and cannot be trailers */
 742        for (start = 0; start < count; start++) {
 743                if (lines[start]->buf[0] == comment_line_char)
 744                        continue;
 745                if (contains_only_spaces(lines[start]->buf))
 746                        break;
 747        }
 748        end_of_title = start;
 749
 750        /*
 751         * Get the start of the trailers by looking starting from the end
 752         * for a line with only spaces before lines with one separator.
 753         */
 754        for (start = count - 1; start >= end_of_title; start--) {
 755                if (lines[start]->buf[0] == comment_line_char)
 756                        continue;
 757                if (contains_only_spaces(lines[start]->buf)) {
 758                        if (only_spaces)
 759                                continue;
 760                        return start + 1;
 761                }
 762                if (strcspn(lines[start]->buf, separators) < lines[start]->len) {
 763                        if (only_spaces)
 764                                only_spaces = 0;
 765                        continue;
 766                }
 767                return count;
 768        }
 769
 770        return only_spaces ? count : 0;
 771}
 772
 773/* Get the index of the end of the trailers */
 774static int find_trailer_end(struct strbuf **lines, int patch_start)
 775{
 776        struct strbuf sb = STRBUF_INIT;
 777        int i, ignore_bytes;
 778
 779        for (i = 0; i < patch_start; i++)
 780                strbuf_addbuf(&sb, lines[i]);
 781        ignore_bytes = ignore_non_trailer(&sb);
 782        strbuf_release(&sb);
 783        for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 784                ignore_bytes -= lines[i]->len;
 785
 786        return i + 1;
 787}
 788
 789static int has_blank_line_before(struct strbuf **lines, int start)
 790{
 791        for (;start >= 0; start--) {
 792                if (lines[start]->buf[0] == comment_line_char)
 793                        continue;
 794                return contains_only_spaces(lines[start]->buf);
 795        }
 796        return 0;
 797}
 798
 799static void print_lines(FILE *outfile, struct strbuf **lines, int start, int end)
 800{
 801        int i;
 802        for (i = start; lines[i] && i < end; i++)
 803                fprintf(outfile, "%s", lines[i]->buf);
 804}
 805
 806static int process_input_file(FILE *outfile,
 807                              struct strbuf **lines,
 808                              struct trailer_item **in_tok_first,
 809                              struct trailer_item **in_tok_last)
 810{
 811        int count = 0;
 812        int patch_start, trailer_start, trailer_end, i;
 813
 814        /* Get the line count */
 815        while (lines[count])
 816                count++;
 817
 818        patch_start = find_patch_start(lines, count);
 819        trailer_end = find_trailer_end(lines, patch_start);
 820        trailer_start = find_trailer_start(lines, trailer_end);
 821
 822        /* Print lines before the trailers as is */
 823        print_lines(outfile, lines, 0, trailer_start);
 824
 825        if (!has_blank_line_before(lines, trailer_start - 1))
 826                fprintf(outfile, "\n");
 827
 828        /* Parse trailer lines */
 829        for (i = trailer_start; i < trailer_end; i++) {
 830                if (lines[i]->buf[0] != comment_line_char) {
 831                        struct trailer_item *new = create_trailer_item(lines[i]->buf);
 832                        add_trailer_item(in_tok_first, in_tok_last, new);
 833                }
 834        }
 835
 836        return trailer_end;
 837}
 838
 839static void free_all(struct trailer_item **first)
 840{
 841        while (*first) {
 842                struct trailer_item *item = remove_first(first);
 843                free_trailer_item(item);
 844        }
 845}
 846
 847static struct tempfile trailers_tempfile;
 848
 849static FILE *create_in_place_tempfile(const char *file)
 850{
 851        struct stat st;
 852        struct strbuf template = STRBUF_INIT;
 853        const char *tail;
 854        FILE *outfile;
 855
 856        if (stat(file, &st))
 857                die_errno(_("could not stat %s"), file);
 858        if (!S_ISREG(st.st_mode))
 859                die(_("file %s is not a regular file"), file);
 860        if (!(st.st_mode & S_IWUSR))
 861                die(_("file %s is not writable by user"), file);
 862
 863        /* Create temporary file in the same directory as the original */
 864        tail = strrchr(file, '/');
 865        if (tail != NULL)
 866                strbuf_add(&template, file, tail - file + 1);
 867        strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 868
 869        xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 870        strbuf_release(&template);
 871        outfile = fdopen_tempfile(&trailers_tempfile, "w");
 872        if (!outfile)
 873                die_errno(_("could not open temporary file"));
 874
 875        return outfile;
 876}
 877
 878void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
 879{
 880        struct trailer_item *in_tok_first = NULL;
 881        struct trailer_item *in_tok_last = NULL;
 882        struct trailer_item *arg_tok_first;
 883        struct strbuf **lines;
 884        int trailer_end;
 885        FILE *outfile = stdout;
 886
 887        /* Default config must be setup first */
 888        git_config(git_trailer_default_config, NULL);
 889        git_config(git_trailer_config, NULL);
 890
 891        lines = read_input_file(file);
 892
 893        if (in_place)
 894                outfile = create_in_place_tempfile(file);
 895
 896        /* Print the lines before the trailers */
 897        trailer_end = process_input_file(outfile, lines, &in_tok_first, &in_tok_last);
 898
 899        arg_tok_first = process_command_line_args(trailers);
 900
 901        process_trailers_lists(&in_tok_first, &in_tok_last, &arg_tok_first);
 902
 903        print_all(outfile, in_tok_first, trim_empty);
 904
 905        free_all(&in_tok_first);
 906
 907        /* Print the lines after the trailers as is */
 908        print_lines(outfile, lines, trailer_end, INT_MAX);
 909
 910        if (in_place)
 911                if (rename_tempfile(&trailers_tempfile, file))
 912                        die_errno(_("could not rename temporary file to %s"), file);
 913
 914        strbuf_list_free(lines);
 915}