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