Merge branch 'nd/lockfile-absolute'
[git] / trailer.c
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
11 enum action_where { WHERE_END, WHERE_AFTER, WHERE_BEFORE, WHERE_START };
12 enum action_if_exists { EXISTS_ADD_IF_DIFFERENT_NEIGHBOR, EXISTS_ADD_IF_DIFFERENT,
13                         EXISTS_ADD, EXISTS_REPLACE, EXISTS_DO_NOTHING };
14 enum action_if_missing { MISSING_ADD, MISSING_DO_NOTHING };
15
16 struct 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
25 static struct conf_info default_conf_info;
26
27 struct 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
35 static struct trailer_item *first_conf_item;
36
37 static char *separators = ":";
38
39 #define TRAILER_ARG_STRING "$ARG"
40
41 static 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  */
52 static 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
59 static 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
68 static int same_value(struct trailer_item *a, struct trailer_item *b)
69 {
70         return !strcasecmp(a->value, b->value);
71 }
72
73 static int same_trailer(struct trailer_item *a, struct trailer_item *b)
74 {
75         return same_token(a, b) && same_value(a, b);
76 }
77
78 static 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
86 static 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
93 static 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
103 static 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
112 static 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
123 static 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
132 static void update_last(struct trailer_item **last)
133 {
134         if (*last)
135                 while ((*last)->next != NULL)
136                         *last = (*last)->next;
137 }
138
139 static void update_first(struct trailer_item **first)
140 {
141         if (*first)
142                 while ((*first)->previous != NULL)
143                         *first = (*first)->previous;
144 }
145
146 static 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
168 static 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
187 static 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
207 static 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
218 static 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
228 static 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
257 static 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
274 static 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
315 static 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
341 static 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
366 static 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
393 static 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
408 static 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
425 static 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
436 static 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
447 static 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
475 enum trailer_info_type { TRAILER_KEY, TRAILER_COMMAND, TRAILER_WHERE,
476                          TRAILER_IF_EXISTS, TRAILER_IF_MISSING };
477
478 static 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
489 static 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
517 static 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
578 static 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
604 static 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
613 static 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
631 static 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
638 static 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
663 static 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
679 static 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
703 static 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  */
727 static 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  */
745 static 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 */
773 static 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
788 static 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
798 static 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
805 static 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
837 static 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
845 void 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 }