Andrew's git / gitweb.git / trailer.c
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trailer.con commit Merge branch 'jk/readme-gmane-is-no-more' into maint (bc7547f)
   1#include "cache.h"
   2#include "string-list.h"
   3#include "run-command.h"
   4#include "commit.h"
   5#include "tempfile.h"
   6#include "trailer.h"
   7#include "list.h"
   8/*
   9 * Copyright (c) 2013, 2014 Christian Couder <chriscool@tuxfamily.org>
  10 */
  11
  12enum action_where { WHERE_END, WHERE_AFTER, WHERE_BEFORE, WHERE_START };
  13enum action_if_exists { EXISTS_ADD_IF_DIFFERENT_NEIGHBOR, EXISTS_ADD_IF_DIFFERENT,
  14                        EXISTS_ADD, EXISTS_REPLACE, EXISTS_DO_NOTHING };
  15enum action_if_missing { MISSING_ADD, MISSING_DO_NOTHING };
  16
  17struct conf_info {
  18        char *name;
  19        char *key;
  20        char *command;
  21        enum action_where where;
  22        enum action_if_exists if_exists;
  23        enum action_if_missing if_missing;
  24};
  25
  26static struct conf_info default_conf_info;
  27
  28struct trailer_item {
  29        struct list_head list;
  30        /*
  31         * If this is not a trailer line, the line is stored in value
  32         * (excluding the terminating newline) and token is NULL.
  33         */
  34        char *token;
  35        char *value;
  36};
  37
  38struct arg_item {
  39        struct list_head list;
  40        char *token;
  41        char *value;
  42        struct conf_info conf;
  43};
  44
  45static LIST_HEAD(conf_head);
  46
  47static char *separators = ":";
  48
  49#define TRAILER_ARG_STRING "$ARG"
  50
  51static const char *git_generated_prefixes[] = {
  52        "Signed-off-by: ",
  53        "(cherry picked from commit ",
  54        NULL
  55};
  56
  57/* Iterate over the elements of the list. */
  58#define list_for_each_dir(pos, head, is_reverse) \
  59        for (pos = is_reverse ? (head)->prev : (head)->next; \
  60                pos != (head); \
  61                pos = is_reverse ? pos->prev : pos->next)
  62
  63static int after_or_end(enum action_where where)
  64{
  65        return (where == WHERE_AFTER) || (where == WHERE_END);
  66}
  67
  68/*
  69 * Return the length of the string not including any final
  70 * punctuation. E.g., the input "Signed-off-by:" would return
  71 * 13, stripping the trailing punctuation but retaining
  72 * internal punctuation.
  73 */
  74static size_t token_len_without_separator(const char *token, size_t len)
  75{
  76        while (len > 0 && !isalnum(token[len - 1]))
  77                len--;
  78        return len;
  79}
  80
  81static int same_token(struct trailer_item *a, struct arg_item *b)
  82{
  83        size_t a_len, b_len, min_len;
  84
  85        if (!a->token)
  86                return 0;
  87
  88        a_len = token_len_without_separator(a->token, strlen(a->token));
  89        b_len = token_len_without_separator(b->token, strlen(b->token));
  90        min_len = (a_len > b_len) ? b_len : a_len;
  91
  92        return !strncasecmp(a->token, b->token, min_len);
  93}
  94
  95static int same_value(struct trailer_item *a, struct arg_item *b)
  96{
  97        return !strcasecmp(a->value, b->value);
  98}
  99
 100static int same_trailer(struct trailer_item *a, struct arg_item *b)
 101{
 102        return same_token(a, b) && same_value(a, b);
 103}
 104
 105static inline int contains_only_spaces(const char *str)
 106{
 107        const char *s = str;
 108        while (*s && isspace(*s))
 109                s++;
 110        return !*s;
 111}
 112
 113static inline void strbuf_replace(struct strbuf *sb, const char *a, const char *b)
 114{
 115        const char *ptr = strstr(sb->buf, a);
 116        if (ptr)
 117                strbuf_splice(sb, ptr - sb->buf, strlen(a), b, strlen(b));
 118}
 119
 120static void free_trailer_item(struct trailer_item *item)
 121{
 122        free(item->token);
 123        free(item->value);
 124        free(item);
 125}
 126
 127static void free_arg_item(struct arg_item *item)
 128{
 129        free(item->conf.name);
 130        free(item->conf.key);
 131        free(item->conf.command);
 132        free(item->token);
 133        free(item->value);
 134        free(item);
 135}
 136
 137static char last_non_space_char(const char *s)
 138{
 139        int i;
 140        for (i = strlen(s) - 1; i >= 0; i--)
 141                if (!isspace(s[i]))
 142                        return s[i];
 143        return '\0';
 144}
 145
 146static void print_tok_val(FILE *outfile, const char *tok, const char *val)
 147{
 148        char c;
 149
 150        if (!tok) {
 151                fprintf(outfile, "%s\n", val);
 152                return;
 153        }
 154
 155        c = last_non_space_char(tok);
 156        if (!c)
 157                return;
 158        if (strchr(separators, c))
 159                fprintf(outfile, "%s%s\n", tok, val);
 160        else
 161                fprintf(outfile, "%s%c %s\n", tok, separators[0], val);
 162}
 163
 164static void print_all(FILE *outfile, struct list_head *head, int trim_empty)
 165{
 166        struct list_head *pos;
 167        struct trailer_item *item;
 168        list_for_each(pos, head) {
 169                item = list_entry(pos, struct trailer_item, list);
 170                if (!trim_empty || strlen(item->value) > 0)
 171                        print_tok_val(outfile, item->token, item->value);
 172        }
 173}
 174
 175static struct trailer_item *trailer_from_arg(struct arg_item *arg_tok)
 176{
 177        struct trailer_item *new = xcalloc(sizeof(*new), 1);
 178        new->token = arg_tok->token;
 179        new->value = arg_tok->value;
 180        arg_tok->token = arg_tok->value = NULL;
 181        free_arg_item(arg_tok);
 182        return new;
 183}
 184
 185static void add_arg_to_input_list(struct trailer_item *on_tok,
 186                                  struct arg_item *arg_tok)
 187{
 188        int aoe = after_or_end(arg_tok->conf.where);
 189        struct trailer_item *to_add = trailer_from_arg(arg_tok);
 190        if (aoe)
 191                list_add(&to_add->list, &on_tok->list);
 192        else
 193                list_add_tail(&to_add->list, &on_tok->list);
 194}
 195
 196static int check_if_different(struct trailer_item *in_tok,
 197                              struct arg_item *arg_tok,
 198                              int check_all,
 199                              struct list_head *head)
 200{
 201        enum action_where where = arg_tok->conf.where;
 202        struct list_head *next_head;
 203        do {
 204                if (same_trailer(in_tok, arg_tok))
 205                        return 0;
 206                /*
 207                 * if we want to add a trailer after another one,
 208                 * we have to check those before this one
 209                 */
 210                next_head = after_or_end(where) ? in_tok->list.prev
 211                                                : in_tok->list.next;
 212                if (next_head == head)
 213                        break;
 214                in_tok = list_entry(next_head, struct trailer_item, list);
 215        } while (check_all);
 216        return 1;
 217}
 218
 219static char *apply_command(const char *command, const char *arg)
 220{
 221        struct strbuf cmd = STRBUF_INIT;
 222        struct strbuf buf = STRBUF_INIT;
 223        struct child_process cp = CHILD_PROCESS_INIT;
 224        const char *argv[] = {NULL, NULL};
 225        char *result;
 226
 227        strbuf_addstr(&cmd, command);
 228        if (arg)
 229                strbuf_replace(&cmd, TRAILER_ARG_STRING, arg);
 230
 231        argv[0] = cmd.buf;
 232        cp.argv = argv;
 233        cp.env = local_repo_env;
 234        cp.no_stdin = 1;
 235        cp.use_shell = 1;
 236
 237        if (capture_command(&cp, &buf, 1024)) {
 238                error(_("running trailer command '%s' failed"), cmd.buf);
 239                strbuf_release(&buf);
 240                result = xstrdup("");
 241        } else {
 242                strbuf_trim(&buf);
 243                result = strbuf_detach(&buf, NULL);
 244        }
 245
 246        strbuf_release(&cmd);
 247        return result;
 248}
 249
 250static void apply_item_command(struct trailer_item *in_tok, struct arg_item *arg_tok)
 251{
 252        if (arg_tok->conf.command) {
 253                const char *arg;
 254                if (arg_tok->value && arg_tok->value[0]) {
 255                        arg = arg_tok->value;
 256                } else {
 257                        if (in_tok && in_tok->value)
 258                                arg = xstrdup(in_tok->value);
 259                        else
 260                                arg = xstrdup("");
 261                }
 262                arg_tok->value = apply_command(arg_tok->conf.command, arg);
 263                free((char *)arg);
 264        }
 265}
 266
 267static void apply_arg_if_exists(struct trailer_item *in_tok,
 268                                struct arg_item *arg_tok,
 269                                struct trailer_item *on_tok,
 270                                struct list_head *head)
 271{
 272        switch (arg_tok->conf.if_exists) {
 273        case EXISTS_DO_NOTHING:
 274                free_arg_item(arg_tok);
 275                break;
 276        case EXISTS_REPLACE:
 277                apply_item_command(in_tok, arg_tok);
 278                add_arg_to_input_list(on_tok, arg_tok);
 279                list_del(&in_tok->list);
 280                free_trailer_item(in_tok);
 281                break;
 282        case EXISTS_ADD:
 283                apply_item_command(in_tok, arg_tok);
 284                add_arg_to_input_list(on_tok, arg_tok);
 285                break;
 286        case EXISTS_ADD_IF_DIFFERENT:
 287                apply_item_command(in_tok, arg_tok);
 288                if (check_if_different(in_tok, arg_tok, 1, head))
 289                        add_arg_to_input_list(on_tok, arg_tok);
 290                else
 291                        free_arg_item(arg_tok);
 292                break;
 293        case EXISTS_ADD_IF_DIFFERENT_NEIGHBOR:
 294                apply_item_command(in_tok, arg_tok);
 295                if (check_if_different(on_tok, arg_tok, 0, head))
 296                        add_arg_to_input_list(on_tok, arg_tok);
 297                else
 298                        free_arg_item(arg_tok);
 299                break;
 300        }
 301}
 302
 303static void apply_arg_if_missing(struct list_head *head,
 304                                 struct arg_item *arg_tok)
 305{
 306        enum action_where where;
 307        struct trailer_item *to_add;
 308
 309        switch (arg_tok->conf.if_missing) {
 310        case MISSING_DO_NOTHING:
 311                free_arg_item(arg_tok);
 312                break;
 313        case MISSING_ADD:
 314                where = arg_tok->conf.where;
 315                apply_item_command(NULL, arg_tok);
 316                to_add = trailer_from_arg(arg_tok);
 317                if (after_or_end(where))
 318                        list_add_tail(&to_add->list, head);
 319                else
 320                        list_add(&to_add->list, head);
 321        }
 322}
 323
 324static int find_same_and_apply_arg(struct list_head *head,
 325                                   struct arg_item *arg_tok)
 326{
 327        struct list_head *pos;
 328        struct trailer_item *in_tok;
 329        struct trailer_item *on_tok;
 330
 331        enum action_where where = arg_tok->conf.where;
 332        int middle = (where == WHERE_AFTER) || (where == WHERE_BEFORE);
 333        int backwards = after_or_end(where);
 334        struct trailer_item *start_tok;
 335
 336        if (list_empty(head))
 337                return 0;
 338
 339        start_tok = list_entry(backwards ? head->prev : head->next,
 340                               struct trailer_item,
 341                               list);
 342
 343        list_for_each_dir(pos, head, backwards) {
 344                in_tok = list_entry(pos, struct trailer_item, list);
 345                if (!same_token(in_tok, arg_tok))
 346                        continue;
 347                on_tok = middle ? in_tok : start_tok;
 348                apply_arg_if_exists(in_tok, arg_tok, on_tok, head);
 349                return 1;
 350        }
 351        return 0;
 352}
 353
 354static void process_trailers_lists(struct list_head *head,
 355                                   struct list_head *arg_head)
 356{
 357        struct list_head *pos, *p;
 358        struct arg_item *arg_tok;
 359
 360        list_for_each_safe(pos, p, arg_head) {
 361                int applied = 0;
 362                arg_tok = list_entry(pos, struct arg_item, list);
 363
 364                list_del(pos);
 365
 366                applied = find_same_and_apply_arg(head, arg_tok);
 367
 368                if (!applied)
 369                        apply_arg_if_missing(head, arg_tok);
 370        }
 371}
 372
 373static int set_where(struct conf_info *item, const char *value)
 374{
 375        if (!strcasecmp("after", value))
 376                item->where = WHERE_AFTER;
 377        else if (!strcasecmp("before", value))
 378                item->where = WHERE_BEFORE;
 379        else if (!strcasecmp("end", value))
 380                item->where = WHERE_END;
 381        else if (!strcasecmp("start", value))
 382                item->where = WHERE_START;
 383        else
 384                return -1;
 385        return 0;
 386}
 387
 388static int set_if_exists(struct conf_info *item, const char *value)
 389{
 390        if (!strcasecmp("addIfDifferent", value))
 391                item->if_exists = EXISTS_ADD_IF_DIFFERENT;
 392        else if (!strcasecmp("addIfDifferentNeighbor", value))
 393                item->if_exists = EXISTS_ADD_IF_DIFFERENT_NEIGHBOR;
 394        else if (!strcasecmp("add", value))
 395                item->if_exists = EXISTS_ADD;
 396        else if (!strcasecmp("replace", value))
 397                item->if_exists = EXISTS_REPLACE;
 398        else if (!strcasecmp("doNothing", value))
 399                item->if_exists = EXISTS_DO_NOTHING;
 400        else
 401                return -1;
 402        return 0;
 403}
 404
 405static int set_if_missing(struct conf_info *item, const char *value)
 406{
 407        if (!strcasecmp("doNothing", value))
 408                item->if_missing = MISSING_DO_NOTHING;
 409        else if (!strcasecmp("add", value))
 410                item->if_missing = MISSING_ADD;
 411        else
 412                return -1;
 413        return 0;
 414}
 415
 416static void duplicate_conf(struct conf_info *dst, const struct conf_info *src)
 417{
 418        *dst = *src;
 419        dst->name = xstrdup_or_null(src->name);
 420        dst->key = xstrdup_or_null(src->key);
 421        dst->command = xstrdup_or_null(src->command);
 422}
 423
 424static struct arg_item *get_conf_item(const char *name)
 425{
 426        struct list_head *pos;
 427        struct arg_item *item;
 428
 429        /* Look up item with same name */
 430        list_for_each(pos, &conf_head) {
 431                item = list_entry(pos, struct arg_item, list);
 432                if (!strcasecmp(item->conf.name, name))
 433                        return item;
 434        }
 435
 436        /* Item does not already exists, create it */
 437        item = xcalloc(sizeof(*item), 1);
 438        duplicate_conf(&item->conf, &default_conf_info);
 439        item->conf.name = xstrdup(name);
 440
 441        list_add_tail(&item->list, &conf_head);
 442
 443        return item;
 444}
 445
 446enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
 447                         TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
 448
 449static struct {
 450        const char *name;
 451        enum trailer_info_type type;
 452} trailer_config_items[] = {
 453        { "key", TRAILER_KEY },
 454        { "command", TRAILER_COMMAND },
 455        { "where", TRAILER_WHERE },
 456        { "ifexists", TRAILER_IF_EXISTS },
 457        { "ifmissing", TRAILER_IF_MISSING }
 458};
 459
 460static int git_trailer_default_config(const char *conf_key, const char *value, void *cb)
 461{
 462        const char *trailer_item, *variable_name;
 463
 464        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 465                return 0;
 466
 467        variable_name = strrchr(trailer_item, '.');
 468        if (!variable_name) {
 469                if (!strcmp(trailer_item, "where")) {
 470                        if (set_where(&default_conf_info, value) < 0)
 471                                warning(_("unknown value '%s' for key '%s'"),
 472                                        value, conf_key);
 473                } else if (!strcmp(trailer_item, "ifexists")) {
 474                        if (set_if_exists(&default_conf_info, value) < 0)
 475                                warning(_("unknown value '%s' for key '%s'"),
 476                                        value, conf_key);
 477                } else if (!strcmp(trailer_item, "ifmissing")) {
 478                        if (set_if_missing(&default_conf_info, value) < 0)
 479                                warning(_("unknown value '%s' for key '%s'"),
 480                                        value, conf_key);
 481                } else if (!strcmp(trailer_item, "separators")) {
 482                        separators = xstrdup(value);
 483                }
 484        }
 485        return 0;
 486}
 487
 488static int git_trailer_config(const char *conf_key, const char *value, void *cb)
 489{
 490        const char *trailer_item, *variable_name;
 491        struct arg_item *item;
 492        struct conf_info *conf;
 493        char *name = NULL;
 494        enum trailer_info_type type;
 495        int i;
 496
 497        if (!skip_prefix(conf_key, "trailer.", &trailer_item))
 498                return 0;
 499
 500        variable_name = strrchr(trailer_item, '.');
 501        if (!variable_name)
 502                return 0;
 503
 504        variable_name++;
 505        for (i = 0; i < ARRAY_SIZE(trailer_config_items); i++) {
 506                if (strcmp(trailer_config_items[i].name, variable_name))
 507                        continue;
 508                name = xstrndup(trailer_item,  variable_name - trailer_item - 1);
 509                type = trailer_config_items[i].type;
 510                break;
 511        }
 512
 513        if (!name)
 514                return 0;
 515
 516        item = get_conf_item(name);
 517        conf = &item->conf;
 518        free(name);
 519
 520        switch (type) {
 521        case TRAILER_KEY:
 522                if (conf->key)
 523                        warning(_("more than one %s"), conf_key);
 524                conf->key = xstrdup(value);
 525                break;
 526        case TRAILER_COMMAND:
 527                if (conf->command)
 528                        warning(_("more than one %s"), conf_key);
 529                conf->command = xstrdup(value);
 530                break;
 531        case TRAILER_WHERE:
 532                if (set_where(conf, value))
 533                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 534                break;
 535        case TRAILER_IF_EXISTS:
 536                if (set_if_exists(conf, value))
 537                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 538                break;
 539        case TRAILER_IF_MISSING:
 540                if (set_if_missing(conf, value))
 541                        warning(_("unknown value '%s' for key '%s'"), value, conf_key);
 542                break;
 543        default:
 544                die("BUG: trailer.c: unhandled type %d", type);
 545        }
 546        return 0;
 547}
 548
 549static const char *token_from_item(struct arg_item *item, char *tok)
 550{
 551        if (item->conf.key)
 552                return item->conf.key;
 553        if (tok)
 554                return tok;
 555        return item->conf.name;
 556}
 557
 558static int token_matches_item(const char *tok, struct arg_item *item, int tok_len)
 559{
 560        if (!strncasecmp(tok, item->conf.name, tok_len))
 561                return 1;
 562        return item->conf.key ? !strncasecmp(tok, item->conf.key, tok_len) : 0;
 563}
 564
 565/*
 566 * Return the location of the first separator in line, or -1 if there is no
 567 * separator.
 568 */
 569static int find_separator(const char *line, const char *separators)
 570{
 571        int loc = strcspn(line, separators);
 572        if (!line[loc])
 573                return -1;
 574        return loc;
 575}
 576
 577/*
 578 * Obtain the token, value, and conf from the given trailer.
 579 *
 580 * separator_pos must not be 0, since the token cannot be an empty string.
 581 *
 582 * If separator_pos is -1, interpret the whole trailer as a token.
 583 */
 584static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 585                         const struct conf_info **conf, const char *trailer,
 586                         int separator_pos)
 587{
 588        struct arg_item *item;
 589        int tok_len;
 590        struct list_head *pos;
 591
 592        if (separator_pos != -1) {
 593                strbuf_add(tok, trailer, separator_pos);
 594                strbuf_trim(tok);
 595                strbuf_addstr(val, trailer + separator_pos + 1);
 596                strbuf_trim(val);
 597        } else {
 598                strbuf_addstr(tok, trailer);
 599                strbuf_trim(tok);
 600        }
 601
 602        /* Lookup if the token matches something in the config */
 603        tok_len = token_len_without_separator(tok->buf, tok->len);
 604        if (conf)
 605                *conf = &default_conf_info;
 606        list_for_each(pos, &conf_head) {
 607                item = list_entry(pos, struct arg_item, list);
 608                if (token_matches_item(tok->buf, item, tok_len)) {
 609                        char *tok_buf = strbuf_detach(tok, NULL);
 610                        if (conf)
 611                                *conf = &item->conf;
 612                        strbuf_addstr(tok, token_from_item(item, tok_buf));
 613                        free(tok_buf);
 614                        break;
 615                }
 616        }
 617}
 618
 619static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 620                                             char *val)
 621{
 622        struct trailer_item *new = xcalloc(sizeof(*new), 1);
 623        new->token = tok;
 624        new->value = val;
 625        list_add_tail(&new->list, head);
 626        return new;
 627}
 628
 629static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 630                         const struct conf_info *conf)
 631{
 632        struct arg_item *new = xcalloc(sizeof(*new), 1);
 633        new->token = tok;
 634        new->value = val;
 635        duplicate_conf(&new->conf, conf);
 636        list_add_tail(&new->list, arg_head);
 637}
 638
 639static void process_command_line_args(struct list_head *arg_head,
 640                                      struct string_list *trailers)
 641{
 642        struct string_list_item *tr;
 643        struct arg_item *item;
 644        struct strbuf tok = STRBUF_INIT;
 645        struct strbuf val = STRBUF_INIT;
 646        const struct conf_info *conf;
 647        struct list_head *pos;
 648
 649        /*
 650         * In command-line arguments, '=' is accepted (in addition to the
 651         * separators that are defined).
 652         */
 653        char *cl_separators = xstrfmt("=%s", separators);
 654
 655        /* Add an arg item for each configured trailer with a command */
 656        list_for_each(pos, &conf_head) {
 657                item = list_entry(pos, struct arg_item, list);
 658                if (item->conf.command)
 659                        add_arg_item(arg_head,
 660                                     xstrdup(token_from_item(item, NULL)),
 661                                     xstrdup(""),
 662                                     &item->conf);
 663        }
 664
 665        /* Add an arg item for each trailer on the command line */
 666        for_each_string_list_item(tr, trailers) {
 667                int separator_pos = find_separator(tr->string, cl_separators);
 668                if (separator_pos == 0) {
 669                        struct strbuf sb = STRBUF_INIT;
 670                        strbuf_addstr(&sb, tr->string);
 671                        strbuf_trim(&sb);
 672                        error(_("empty trailer token in trailer '%.*s'"),
 673                              (int) sb.len, sb.buf);
 674                        strbuf_release(&sb);
 675                } else {
 676                        parse_trailer(&tok, &val, &conf, tr->string,
 677                                      separator_pos);
 678                        add_arg_item(arg_head,
 679                                     strbuf_detach(&tok, NULL),
 680                                     strbuf_detach(&val, NULL),
 681                                     conf);
 682                }
 683        }
 684
 685        free(cl_separators);
 686}
 687
 688static struct strbuf **read_input_file(const char *file)
 689{
 690        struct strbuf **lines;
 691        struct strbuf sb = STRBUF_INIT;
 692
 693        if (file) {
 694                if (strbuf_read_file(&sb, file, 0) < 0)
 695                        die_errno(_("could not read input file '%s'"), file);
 696        } else {
 697                if (strbuf_read(&sb, fileno(stdin), 0) < 0)
 698                        die_errno(_("could not read from stdin"));
 699        }
 700
 701        lines = strbuf_split(&sb, '\n');
 702
 703        strbuf_release(&sb);
 704
 705        return lines;
 706}
 707
 708/*
 709 * Return the (0 based) index of the start of the patch or the line
 710 * count if there is no patch in the message.
 711 */
 712static int find_patch_start(struct strbuf **lines, int count)
 713{
 714        int i;
 715
 716        /* Get the start of the patch part if any */
 717        for (i = 0; i < count; i++) {
 718                if (starts_with(lines[i]->buf, "---"))
 719                        return i;
 720        }
 721
 722        return count;
 723}
 724
 725/*
 726 * Return the (0 based) index of the first trailer line or count if
 727 * there are no trailers. Trailers are searched only in the lines from
 728 * index (count - 1) down to index 0.
 729 */
 730static int find_trailer_start(struct strbuf **lines, int count)
 731{
 732        int start, end_of_title, only_spaces = 1;
 733        int recognized_prefix = 0, trailer_lines = 0, non_trailer_lines = 0;
 734        /*
 735         * Number of possible continuation lines encountered. This will be
 736         * reset to 0 if we encounter a trailer (since those lines are to be
 737         * considered continuations of that trailer), and added to
 738         * non_trailer_lines if we encounter a non-trailer (since those lines
 739         * are to be considered non-trailers).
 740         */
 741        int possible_continuation_lines = 0;
 742
 743        /* The first paragraph is the title and cannot be trailers */
 744        for (start = 0; start < count; start++) {
 745                if (lines[start]->buf[0] == comment_line_char)
 746                        continue;
 747                if (contains_only_spaces(lines[start]->buf))
 748                        break;
 749        }
 750        end_of_title = start;
 751
 752        /*
 753         * Get the start of the trailers by looking starting from the end for a
 754         * blank line before a set of non-blank lines that (i) are all
 755         * trailers, or (ii) contains at least one Git-generated trailer and
 756         * consists of at least 25% trailers.
 757         */
 758        for (start = count - 1; start >= end_of_title; start--) {
 759                const char **p;
 760                int separator_pos;
 761
 762                if (lines[start]->buf[0] == comment_line_char) {
 763                        non_trailer_lines += possible_continuation_lines;
 764                        possible_continuation_lines = 0;
 765                        continue;
 766                }
 767                if (contains_only_spaces(lines[start]->buf)) {
 768                        if (only_spaces)
 769                                continue;
 770                        non_trailer_lines += possible_continuation_lines;
 771                        if (recognized_prefix &&
 772                            trailer_lines * 3 >= non_trailer_lines)
 773                                return start + 1;
 774                        if (trailer_lines && !non_trailer_lines)
 775                                return start + 1;
 776                        return count;
 777                }
 778                only_spaces = 0;
 779
 780                for (p = git_generated_prefixes; *p; p++) {
 781                        if (starts_with(lines[start]->buf, *p)) {
 782                                trailer_lines++;
 783                                possible_continuation_lines = 0;
 784                                recognized_prefix = 1;
 785                                goto continue_outer_loop;
 786                        }
 787                }
 788
 789                separator_pos = find_separator(lines[start]->buf, separators);
 790                if (separator_pos >= 1 && !isspace(lines[start]->buf[0])) {
 791                        struct list_head *pos;
 792
 793                        trailer_lines++;
 794                        possible_continuation_lines = 0;
 795                        if (recognized_prefix)
 796                                continue;
 797                        list_for_each(pos, &conf_head) {
 798                                struct arg_item *item;
 799                                item = list_entry(pos, struct arg_item, list);
 800                                if (token_matches_item(lines[start]->buf, item,
 801                                                       separator_pos)) {
 802                                        recognized_prefix = 1;
 803                                        break;
 804                                }
 805                        }
 806                } else if (isspace(lines[start]->buf[0]))
 807                        possible_continuation_lines++;
 808                else {
 809                        non_trailer_lines++;
 810                        non_trailer_lines += possible_continuation_lines;
 811                        possible_continuation_lines = 0;
 812                }
 813continue_outer_loop:
 814                ;
 815        }
 816
 817        return count;
 818}
 819
 820/* Get the index of the end of the trailers */
 821static int find_trailer_end(struct strbuf **lines, int patch_start)
 822{
 823        struct strbuf sb = STRBUF_INIT;
 824        int i, ignore_bytes;
 825
 826        for (i = 0; i < patch_start; i++)
 827                strbuf_addbuf(&sb, lines[i]);
 828        ignore_bytes = ignore_non_trailer(&sb);
 829        strbuf_release(&sb);
 830        for (i = patch_start - 1; i >= 0 && ignore_bytes > 0; i--)
 831                ignore_bytes -= lines[i]->len;
 832
 833        return i + 1;
 834}
 835
 836static int has_blank_line_before(struct strbuf **lines, int start)
 837{
 838        for (;start >= 0; start--) {
 839                if (lines[start]->buf[0] == comment_line_char)
 840                        continue;
 841                return contains_only_spaces(lines[start]->buf);
 842        }
 843        return 0;
 844}
 845
 846static void print_lines(FILE *outfile, struct strbuf **lines, int start, int end)
 847{
 848        int i;
 849        for (i = start; lines[i] && i < end; i++)
 850                fprintf(outfile, "%s", lines[i]->buf);
 851}
 852
 853static int process_input_file(FILE *outfile,
 854                              struct strbuf **lines,
 855                              struct list_head *head)
 856{
 857        int count = 0;
 858        int patch_start, trailer_start, trailer_end, i;
 859        struct strbuf tok = STRBUF_INIT;
 860        struct strbuf val = STRBUF_INIT;
 861        struct trailer_item *last = NULL;
 862
 863        /* Get the line count */
 864        while (lines[count])
 865                count++;
 866
 867        patch_start = find_patch_start(lines, count);
 868        trailer_end = find_trailer_end(lines, patch_start);
 869        trailer_start = find_trailer_start(lines, trailer_end);
 870
 871        /* Print lines before the trailers as is */
 872        print_lines(outfile, lines, 0, trailer_start);
 873
 874        if (!has_blank_line_before(lines, trailer_start - 1))
 875                fprintf(outfile, "\n");
 876
 877        /* Parse trailer lines */
 878        for (i = trailer_start; i < trailer_end; i++) {
 879                int separator_pos;
 880                if (lines[i]->buf[0] == comment_line_char)
 881                        continue;
 882                if (last && isspace(lines[i]->buf[0])) {
 883                        struct strbuf sb = STRBUF_INIT;
 884                        strbuf_addf(&sb, "%s\n%s", last->value, lines[i]->buf);
 885                        strbuf_strip_suffix(&sb, "\n");
 886                        free(last->value);
 887                        last->value = strbuf_detach(&sb, NULL);
 888                        continue;
 889                }
 890                separator_pos = find_separator(lines[i]->buf, separators);
 891                if (separator_pos >= 1) {
 892                        parse_trailer(&tok, &val, NULL, lines[i]->buf,
 893                                      separator_pos);
 894                        last = add_trailer_item(head,
 895                                                strbuf_detach(&tok, NULL),
 896                                                strbuf_detach(&val, NULL));
 897                } else {
 898                        strbuf_addbuf(&val, lines[i]);
 899                        strbuf_strip_suffix(&val, "\n");
 900                        add_trailer_item(head,
 901                                         NULL,
 902                                         strbuf_detach(&val, NULL));
 903                        last = NULL;
 904                }
 905        }
 906
 907        return trailer_end;
 908}
 909
 910static void free_all(struct list_head *head)
 911{
 912        struct list_head *pos, *p;
 913        list_for_each_safe(pos, p, head) {
 914                list_del(pos);
 915                free_trailer_item(list_entry(pos, struct trailer_item, list));
 916        }
 917}
 918
 919static struct tempfile trailers_tempfile;
 920
 921static FILE *create_in_place_tempfile(const char *file)
 922{
 923        struct stat st;
 924        struct strbuf template = STRBUF_INIT;
 925        const char *tail;
 926        FILE *outfile;
 927
 928        if (stat(file, &st))
 929                die_errno(_("could not stat %s"), file);
 930        if (!S_ISREG(st.st_mode))
 931                die(_("file %s is not a regular file"), file);
 932        if (!(st.st_mode & S_IWUSR))
 933                die(_("file %s is not writable by user"), file);
 934
 935        /* Create temporary file in the same directory as the original */
 936        tail = strrchr(file, '/');
 937        if (tail != NULL)
 938                strbuf_add(&template, file, tail - file + 1);
 939        strbuf_addstr(&template, "git-interpret-trailers-XXXXXX");
 940
 941        xmks_tempfile_m(&trailers_tempfile, template.buf, st.st_mode);
 942        strbuf_release(&template);
 943        outfile = fdopen_tempfile(&trailers_tempfile, "w");
 944        if (!outfile)
 945                die_errno(_("could not open temporary file"));
 946
 947        return outfile;
 948}
 949
 950void process_trailers(const char *file, int in_place, int trim_empty, struct string_list *trailers)
 951{
 952        LIST_HEAD(head);
 953        LIST_HEAD(arg_head);
 954        struct strbuf **lines;
 955        int trailer_end;
 956        FILE *outfile = stdout;
 957
 958        /* Default config must be setup first */
 959        git_config(git_trailer_default_config, NULL);
 960        git_config(git_trailer_config, NULL);
 961
 962        lines = read_input_file(file);
 963
 964        if (in_place)
 965                outfile = create_in_place_tempfile(file);
 966
 967        /* Print the lines before the trailers */
 968        trailer_end = process_input_file(outfile, lines, &head);
 969
 970        process_command_line_args(&arg_head, trailers);
 971
 972        process_trailers_lists(&head, &arg_head);
 973
 974        print_all(outfile, &head, trim_empty);
 975
 976        free_all(&head);
 977
 978        /* Print the lines after the trailers as is */
 979        print_lines(outfile, lines, trailer_end, INT_MAX);
 980
 981        if (in_place)
 982                if (rename_tempfile(&trailers_tempfile, file))
 983                        die_errno(_("could not rename temporary file to %s"), file);
 984
 985        strbuf_list_free(lines);
 986}