Merge branch 'jc/am-i-v-fix' into maint
[git] / builtin / am.c
1 /*
2  * Builtin "git am"
3  *
4  * Based on git-am.sh by Junio C Hamano.
5  */
6 #include "cache.h"
7 #include "builtin.h"
8 #include "exec_cmd.h"
9 #include "parse-options.h"
10 #include "dir.h"
11 #include "run-command.h"
12 #include "quote.h"
13 #include "tempfile.h"
14 #include "lockfile.h"
15 #include "cache-tree.h"
16 #include "refs.h"
17 #include "commit.h"
18 #include "diff.h"
19 #include "diffcore.h"
20 #include "unpack-trees.h"
21 #include "branch.h"
22 #include "sequencer.h"
23 #include "revision.h"
24 #include "merge-recursive.h"
25 #include "revision.h"
26 #include "log-tree.h"
27 #include "notes-utils.h"
28 #include "rerere.h"
29 #include "prompt.h"
30 #include "mailinfo.h"
31
32 /**
33  * Returns 1 if the file is empty or does not exist, 0 otherwise.
34  */
35 static int is_empty_file(const char *filename)
36 {
37         struct stat st;
38
39         if (stat(filename, &st) < 0) {
40                 if (errno == ENOENT)
41                         return 1;
42                 die_errno(_("could not stat %s"), filename);
43         }
44
45         return !st.st_size;
46 }
47
48 /**
49  * Like strbuf_getline(), but treats both '\n' and "\r\n" as line terminators.
50  */
51 static int strbuf_getline_crlf(struct strbuf *sb, FILE *fp)
52 {
53         if (strbuf_getwholeline(sb, fp, '\n'))
54                 return EOF;
55         if (sb->buf[sb->len - 1] == '\n') {
56                 strbuf_setlen(sb, sb->len - 1);
57                 if (sb->len > 0 && sb->buf[sb->len - 1] == '\r')
58                         strbuf_setlen(sb, sb->len - 1);
59         }
60         return 0;
61 }
62
63 /**
64  * Returns the length of the first line of msg.
65  */
66 static int linelen(const char *msg)
67 {
68         return strchrnul(msg, '\n') - msg;
69 }
70
71 /**
72  * Returns true if `str` consists of only whitespace, false otherwise.
73  */
74 static int str_isspace(const char *str)
75 {
76         for (; *str; str++)
77                 if (!isspace(*str))
78                         return 0;
79
80         return 1;
81 }
82
83 enum patch_format {
84         PATCH_FORMAT_UNKNOWN = 0,
85         PATCH_FORMAT_MBOX,
86         PATCH_FORMAT_STGIT,
87         PATCH_FORMAT_STGIT_SERIES,
88         PATCH_FORMAT_HG
89 };
90
91 enum keep_type {
92         KEEP_FALSE = 0,
93         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
94         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
95 };
96
97 enum scissors_type {
98         SCISSORS_UNSET = -1,
99         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
100         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
101 };
102
103 enum signoff_type {
104         SIGNOFF_FALSE = 0,
105         SIGNOFF_TRUE = 1,
106         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
107 };
108
109 struct am_state {
110         /* state directory path */
111         char *dir;
112
113         /* current and last patch numbers, 1-indexed */
114         int cur;
115         int last;
116
117         /* commit metadata and message */
118         char *author_name;
119         char *author_email;
120         char *author_date;
121         char *msg;
122         size_t msg_len;
123
124         /* when --rebasing, records the original commit the patch came from */
125         unsigned char orig_commit[GIT_SHA1_RAWSZ];
126
127         /* number of digits in patch filename */
128         int prec;
129
130         /* various operating modes and command line options */
131         int interactive;
132         int threeway;
133         int quiet;
134         int signoff; /* enum signoff_type */
135         int utf8;
136         int keep; /* enum keep_type */
137         int message_id;
138         int scissors; /* enum scissors_type */
139         struct argv_array git_apply_opts;
140         const char *resolvemsg;
141         int committer_date_is_author_date;
142         int ignore_date;
143         int allow_rerere_autoupdate;
144         const char *sign_commit;
145         int rebasing;
146 };
147
148 /**
149  * Initializes am_state with the default values. The state directory is set to
150  * dir.
151  */
152 static void am_state_init(struct am_state *state, const char *dir)
153 {
154         int gpgsign;
155
156         memset(state, 0, sizeof(*state));
157
158         assert(dir);
159         state->dir = xstrdup(dir);
160
161         state->prec = 4;
162
163         git_config_get_bool("am.threeway", &state->threeway);
164
165         state->utf8 = 1;
166
167         git_config_get_bool("am.messageid", &state->message_id);
168
169         state->scissors = SCISSORS_UNSET;
170
171         argv_array_init(&state->git_apply_opts);
172
173         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
174                 state->sign_commit = gpgsign ? "" : NULL;
175 }
176
177 /**
178  * Releases memory allocated by an am_state.
179  */
180 static void am_state_release(struct am_state *state)
181 {
182         free(state->dir);
183         free(state->author_name);
184         free(state->author_email);
185         free(state->author_date);
186         free(state->msg);
187         argv_array_clear(&state->git_apply_opts);
188 }
189
190 /**
191  * Returns path relative to the am_state directory.
192  */
193 static inline const char *am_path(const struct am_state *state, const char *path)
194 {
195         return mkpath("%s/%s", state->dir, path);
196 }
197
198 /**
199  * For convenience to call write_file()
200  */
201 static int write_state_text(const struct am_state *state,
202                             const char *name, const char *string)
203 {
204         return write_file(am_path(state, name), "%s", string);
205 }
206
207 static int write_state_count(const struct am_state *state,
208                              const char *name, int value)
209 {
210         return write_file(am_path(state, name), "%d", value);
211 }
212
213 static int write_state_bool(const struct am_state *state,
214                             const char *name, int value)
215 {
216         return write_state_text(state, name, value ? "t" : "f");
217 }
218
219 /**
220  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
221  * at the end.
222  */
223 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
224 {
225         va_list ap;
226
227         va_start(ap, fmt);
228         if (!state->quiet) {
229                 vfprintf(fp, fmt, ap);
230                 putc('\n', fp);
231         }
232         va_end(ap);
233 }
234
235 /**
236  * Returns 1 if there is an am session in progress, 0 otherwise.
237  */
238 static int am_in_progress(const struct am_state *state)
239 {
240         struct stat st;
241
242         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
243                 return 0;
244         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
245                 return 0;
246         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
247                 return 0;
248         return 1;
249 }
250
251 /**
252  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
253  * number of bytes read on success, -1 if the file does not exist. If `trim` is
254  * set, trailing whitespace will be removed.
255  */
256 static int read_state_file(struct strbuf *sb, const struct am_state *state,
257                         const char *file, int trim)
258 {
259         strbuf_reset(sb);
260
261         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
262                 if (trim)
263                         strbuf_trim(sb);
264
265                 return sb->len;
266         }
267
268         if (errno == ENOENT)
269                 return -1;
270
271         die_errno(_("could not read '%s'"), am_path(state, file));
272 }
273
274 /**
275  * Reads a KEY=VALUE shell variable assignment from `fp`, returning the VALUE
276  * as a newly-allocated string. VALUE must be a quoted string, and the KEY must
277  * match `key`. Returns NULL on failure.
278  *
279  * This is used by read_author_script() to read the GIT_AUTHOR_* variables from
280  * the author-script.
281  */
282 static char *read_shell_var(FILE *fp, const char *key)
283 {
284         struct strbuf sb = STRBUF_INIT;
285         const char *str;
286
287         if (strbuf_getline(&sb, fp, '\n'))
288                 goto fail;
289
290         if (!skip_prefix(sb.buf, key, &str))
291                 goto fail;
292
293         if (!skip_prefix(str, "=", &str))
294                 goto fail;
295
296         strbuf_remove(&sb, 0, str - sb.buf);
297
298         str = sq_dequote(sb.buf);
299         if (!str)
300                 goto fail;
301
302         return strbuf_detach(&sb, NULL);
303
304 fail:
305         strbuf_release(&sb);
306         return NULL;
307 }
308
309 /**
310  * Reads and parses the state directory's "author-script" file, and sets
311  * state->author_name, state->author_email and state->author_date accordingly.
312  * Returns 0 on success, -1 if the file could not be parsed.
313  *
314  * The author script is of the format:
315  *
316  *      GIT_AUTHOR_NAME='$author_name'
317  *      GIT_AUTHOR_EMAIL='$author_email'
318  *      GIT_AUTHOR_DATE='$author_date'
319  *
320  * where $author_name, $author_email and $author_date are quoted. We are strict
321  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
322  * script, and thus if the file differs from what this function expects, it is
323  * better to bail out than to do something that the user does not expect.
324  */
325 static int read_author_script(struct am_state *state)
326 {
327         const char *filename = am_path(state, "author-script");
328         FILE *fp;
329
330         assert(!state->author_name);
331         assert(!state->author_email);
332         assert(!state->author_date);
333
334         fp = fopen(filename, "r");
335         if (!fp) {
336                 if (errno == ENOENT)
337                         return 0;
338                 die_errno(_("could not open '%s' for reading"), filename);
339         }
340
341         state->author_name = read_shell_var(fp, "GIT_AUTHOR_NAME");
342         if (!state->author_name) {
343                 fclose(fp);
344                 return -1;
345         }
346
347         state->author_email = read_shell_var(fp, "GIT_AUTHOR_EMAIL");
348         if (!state->author_email) {
349                 fclose(fp);
350                 return -1;
351         }
352
353         state->author_date = read_shell_var(fp, "GIT_AUTHOR_DATE");
354         if (!state->author_date) {
355                 fclose(fp);
356                 return -1;
357         }
358
359         if (fgetc(fp) != EOF) {
360                 fclose(fp);
361                 return -1;
362         }
363
364         fclose(fp);
365         return 0;
366 }
367
368 /**
369  * Saves state->author_name, state->author_email and state->author_date in the
370  * state directory's "author-script" file.
371  */
372 static void write_author_script(const struct am_state *state)
373 {
374         struct strbuf sb = STRBUF_INIT;
375
376         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
377         sq_quote_buf(&sb, state->author_name);
378         strbuf_addch(&sb, '\n');
379
380         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
381         sq_quote_buf(&sb, state->author_email);
382         strbuf_addch(&sb, '\n');
383
384         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
385         sq_quote_buf(&sb, state->author_date);
386         strbuf_addch(&sb, '\n');
387
388         write_state_text(state, "author-script", sb.buf);
389
390         strbuf_release(&sb);
391 }
392
393 /**
394  * Reads the commit message from the state directory's "final-commit" file,
395  * setting state->msg to its contents and state->msg_len to the length of its
396  * contents in bytes.
397  *
398  * Returns 0 on success, -1 if the file does not exist.
399  */
400 static int read_commit_msg(struct am_state *state)
401 {
402         struct strbuf sb = STRBUF_INIT;
403
404         assert(!state->msg);
405
406         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
407                 strbuf_release(&sb);
408                 return -1;
409         }
410
411         state->msg = strbuf_detach(&sb, &state->msg_len);
412         return 0;
413 }
414
415 /**
416  * Saves state->msg in the state directory's "final-commit" file.
417  */
418 static void write_commit_msg(const struct am_state *state)
419 {
420         int fd;
421         const char *filename = am_path(state, "final-commit");
422
423         fd = xopen(filename, O_WRONLY | O_CREAT, 0666);
424         if (write_in_full(fd, state->msg, state->msg_len) < 0)
425                 die_errno(_("could not write to %s"), filename);
426         close(fd);
427 }
428
429 /**
430  * Loads state from disk.
431  */
432 static void am_load(struct am_state *state)
433 {
434         struct strbuf sb = STRBUF_INIT;
435
436         if (read_state_file(&sb, state, "next", 1) < 0)
437                 die("BUG: state file 'next' does not exist");
438         state->cur = strtol(sb.buf, NULL, 10);
439
440         if (read_state_file(&sb, state, "last", 1) < 0)
441                 die("BUG: state file 'last' does not exist");
442         state->last = strtol(sb.buf, NULL, 10);
443
444         if (read_author_script(state) < 0)
445                 die(_("could not parse author script"));
446
447         read_commit_msg(state);
448
449         if (read_state_file(&sb, state, "original-commit", 1) < 0)
450                 hashclr(state->orig_commit);
451         else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
452                 die(_("could not parse %s"), am_path(state, "original-commit"));
453
454         read_state_file(&sb, state, "threeway", 1);
455         state->threeway = !strcmp(sb.buf, "t");
456
457         read_state_file(&sb, state, "quiet", 1);
458         state->quiet = !strcmp(sb.buf, "t");
459
460         read_state_file(&sb, state, "sign", 1);
461         state->signoff = !strcmp(sb.buf, "t");
462
463         read_state_file(&sb, state, "utf8", 1);
464         state->utf8 = !strcmp(sb.buf, "t");
465
466         read_state_file(&sb, state, "keep", 1);
467         if (!strcmp(sb.buf, "t"))
468                 state->keep = KEEP_TRUE;
469         else if (!strcmp(sb.buf, "b"))
470                 state->keep = KEEP_NON_PATCH;
471         else
472                 state->keep = KEEP_FALSE;
473
474         read_state_file(&sb, state, "messageid", 1);
475         state->message_id = !strcmp(sb.buf, "t");
476
477         read_state_file(&sb, state, "scissors", 1);
478         if (!strcmp(sb.buf, "t"))
479                 state->scissors = SCISSORS_TRUE;
480         else if (!strcmp(sb.buf, "f"))
481                 state->scissors = SCISSORS_FALSE;
482         else
483                 state->scissors = SCISSORS_UNSET;
484
485         read_state_file(&sb, state, "apply-opt", 1);
486         argv_array_clear(&state->git_apply_opts);
487         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
488                 die(_("could not parse %s"), am_path(state, "apply-opt"));
489
490         state->rebasing = !!file_exists(am_path(state, "rebasing"));
491
492         strbuf_release(&sb);
493 }
494
495 /**
496  * Removes the am_state directory, forcefully terminating the current am
497  * session.
498  */
499 static void am_destroy(const struct am_state *state)
500 {
501         struct strbuf sb = STRBUF_INIT;
502
503         strbuf_addstr(&sb, state->dir);
504         remove_dir_recursively(&sb, 0);
505         strbuf_release(&sb);
506 }
507
508 /**
509  * Runs applypatch-msg hook. Returns its exit code.
510  */
511 static int run_applypatch_msg_hook(struct am_state *state)
512 {
513         int ret;
514
515         assert(state->msg);
516         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
517
518         if (!ret) {
519                 free(state->msg);
520                 state->msg = NULL;
521                 if (read_commit_msg(state) < 0)
522                         die(_("'%s' was deleted by the applypatch-msg hook"),
523                                 am_path(state, "final-commit"));
524         }
525
526         return ret;
527 }
528
529 /**
530  * Runs post-rewrite hook. Returns it exit code.
531  */
532 static int run_post_rewrite_hook(const struct am_state *state)
533 {
534         struct child_process cp = CHILD_PROCESS_INIT;
535         const char *hook = find_hook("post-rewrite");
536         int ret;
537
538         if (!hook)
539                 return 0;
540
541         argv_array_push(&cp.args, hook);
542         argv_array_push(&cp.args, "rebase");
543
544         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
545         cp.stdout_to_stderr = 1;
546
547         ret = run_command(&cp);
548
549         close(cp.in);
550         return ret;
551 }
552
553 /**
554  * Reads the state directory's "rewritten" file, and copies notes from the old
555  * commits listed in the file to their rewritten commits.
556  *
557  * Returns 0 on success, -1 on failure.
558  */
559 static int copy_notes_for_rebase(const struct am_state *state)
560 {
561         struct notes_rewrite_cfg *c;
562         struct strbuf sb = STRBUF_INIT;
563         const char *invalid_line = _("Malformed input line: '%s'.");
564         const char *msg = "Notes added by 'git rebase'";
565         FILE *fp;
566         int ret = 0;
567
568         assert(state->rebasing);
569
570         c = init_copy_notes_for_rewrite("rebase");
571         if (!c)
572                 return 0;
573
574         fp = xfopen(am_path(state, "rewritten"), "r");
575
576         while (!strbuf_getline(&sb, fp, '\n')) {
577                 unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
578
579                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
580                         ret = error(invalid_line, sb.buf);
581                         goto finish;
582                 }
583
584                 if (get_sha1_hex(sb.buf, from_obj)) {
585                         ret = error(invalid_line, sb.buf);
586                         goto finish;
587                 }
588
589                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
590                         ret = error(invalid_line, sb.buf);
591                         goto finish;
592                 }
593
594                 if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
595                         ret = error(invalid_line, sb.buf);
596                         goto finish;
597                 }
598
599                 if (copy_note_for_rewrite(c, from_obj, to_obj))
600                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
601                                         sha1_to_hex(from_obj), sha1_to_hex(to_obj));
602         }
603
604 finish:
605         finish_copy_notes_for_rewrite(c, msg);
606         fclose(fp);
607         strbuf_release(&sb);
608         return ret;
609 }
610
611 /**
612  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
613  * non-indented lines and checking if they look like they begin with valid
614  * header field names.
615  *
616  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
617  */
618 static int is_mail(FILE *fp)
619 {
620         const char *header_regex = "^[!-9;-~]+:";
621         struct strbuf sb = STRBUF_INIT;
622         regex_t regex;
623         int ret = 1;
624
625         if (fseek(fp, 0L, SEEK_SET))
626                 die_errno(_("fseek failed"));
627
628         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
629                 die("invalid pattern: %s", header_regex);
630
631         while (!strbuf_getline_crlf(&sb, fp)) {
632                 if (!sb.len)
633                         break; /* End of header */
634
635                 /* Ignore indented folded lines */
636                 if (*sb.buf == '\t' || *sb.buf == ' ')
637                         continue;
638
639                 /* It's a header if it matches header_regex */
640                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
641                         ret = 0;
642                         goto done;
643                 }
644         }
645
646 done:
647         regfree(&regex);
648         strbuf_release(&sb);
649         return ret;
650 }
651
652 /**
653  * Attempts to detect the patch_format of the patches contained in `paths`,
654  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
655  * detection fails.
656  */
657 static int detect_patch_format(const char **paths)
658 {
659         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
660         struct strbuf l1 = STRBUF_INIT;
661         struct strbuf l2 = STRBUF_INIT;
662         struct strbuf l3 = STRBUF_INIT;
663         FILE *fp;
664
665         /*
666          * We default to mbox format if input is from stdin and for directories
667          */
668         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
669                 return PATCH_FORMAT_MBOX;
670
671         /*
672          * Otherwise, check the first few lines of the first patch, starting
673          * from the first non-blank line, to try to detect its format.
674          */
675
676         fp = xfopen(*paths, "r");
677
678         while (!strbuf_getline_crlf(&l1, fp)) {
679                 if (l1.len)
680                         break;
681         }
682
683         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
684                 ret = PATCH_FORMAT_MBOX;
685                 goto done;
686         }
687
688         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
689                 ret = PATCH_FORMAT_STGIT_SERIES;
690                 goto done;
691         }
692
693         if (!strcmp(l1.buf, "# HG changeset patch")) {
694                 ret = PATCH_FORMAT_HG;
695                 goto done;
696         }
697
698         strbuf_reset(&l2);
699         strbuf_getline_crlf(&l2, fp);
700         strbuf_reset(&l3);
701         strbuf_getline_crlf(&l3, fp);
702
703         /*
704          * If the second line is empty and the third is a From, Author or Date
705          * entry, this is likely an StGit patch.
706          */
707         if (l1.len && !l2.len &&
708                 (starts_with(l3.buf, "From:") ||
709                  starts_with(l3.buf, "Author:") ||
710                  starts_with(l3.buf, "Date:"))) {
711                 ret = PATCH_FORMAT_STGIT;
712                 goto done;
713         }
714
715         if (l1.len && is_mail(fp)) {
716                 ret = PATCH_FORMAT_MBOX;
717                 goto done;
718         }
719
720 done:
721         fclose(fp);
722         strbuf_release(&l1);
723         return ret;
724 }
725
726 /**
727  * Splits out individual email patches from `paths`, where each path is either
728  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
729  */
730 static int split_mail_mbox(struct am_state *state, const char **paths, int keep_cr)
731 {
732         struct child_process cp = CHILD_PROCESS_INIT;
733         struct strbuf last = STRBUF_INIT;
734
735         cp.git_cmd = 1;
736         argv_array_push(&cp.args, "mailsplit");
737         argv_array_pushf(&cp.args, "-d%d", state->prec);
738         argv_array_pushf(&cp.args, "-o%s", state->dir);
739         argv_array_push(&cp.args, "-b");
740         if (keep_cr)
741                 argv_array_push(&cp.args, "--keep-cr");
742         argv_array_push(&cp.args, "--");
743         argv_array_pushv(&cp.args, paths);
744
745         if (capture_command(&cp, &last, 8))
746                 return -1;
747
748         state->cur = 1;
749         state->last = strtol(last.buf, NULL, 10);
750
751         return 0;
752 }
753
754 /**
755  * Callback signature for split_mail_conv(). The foreign patch should be
756  * read from `in`, and the converted patch (in RFC2822 mail format) should be
757  * written to `out`. Return 0 on success, or -1 on failure.
758  */
759 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
760
761 /**
762  * Calls `fn` for each file in `paths` to convert the foreign patch to the
763  * RFC2822 mail format suitable for parsing with git-mailinfo.
764  *
765  * Returns 0 on success, -1 on failure.
766  */
767 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
768                         const char **paths, int keep_cr)
769 {
770         static const char *stdin_only[] = {"-", NULL};
771         int i;
772
773         if (!*paths)
774                 paths = stdin_only;
775
776         for (i = 0; *paths; paths++, i++) {
777                 FILE *in, *out;
778                 const char *mail;
779                 int ret;
780
781                 if (!strcmp(*paths, "-"))
782                         in = stdin;
783                 else
784                         in = fopen(*paths, "r");
785
786                 if (!in)
787                         return error(_("could not open '%s' for reading: %s"),
788                                         *paths, strerror(errno));
789
790                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
791
792                 out = fopen(mail, "w");
793                 if (!out)
794                         return error(_("could not open '%s' for writing: %s"),
795                                         mail, strerror(errno));
796
797                 ret = fn(out, in, keep_cr);
798
799                 fclose(out);
800                 fclose(in);
801
802                 if (ret)
803                         return error(_("could not parse patch '%s'"), *paths);
804         }
805
806         state->cur = 1;
807         state->last = i;
808         return 0;
809 }
810
811 /**
812  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
813  * message suitable for parsing with git-mailinfo.
814  */
815 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
816 {
817         struct strbuf sb = STRBUF_INIT;
818         int subject_printed = 0;
819
820         while (!strbuf_getline(&sb, in, '\n')) {
821                 const char *str;
822
823                 if (str_isspace(sb.buf))
824                         continue;
825                 else if (skip_prefix(sb.buf, "Author:", &str))
826                         fprintf(out, "From:%s\n", str);
827                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
828                         fprintf(out, "%s\n", sb.buf);
829                 else if (!subject_printed) {
830                         fprintf(out, "Subject: %s\n", sb.buf);
831                         subject_printed = 1;
832                 } else {
833                         fprintf(out, "\n%s\n", sb.buf);
834                         break;
835                 }
836         }
837
838         strbuf_reset(&sb);
839         while (strbuf_fread(&sb, 8192, in) > 0) {
840                 fwrite(sb.buf, 1, sb.len, out);
841                 strbuf_reset(&sb);
842         }
843
844         strbuf_release(&sb);
845         return 0;
846 }
847
848 /**
849  * This function only supports a single StGit series file in `paths`.
850  *
851  * Given an StGit series file, converts the StGit patches in the series into
852  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
853  * the state directory.
854  *
855  * Returns 0 on success, -1 on failure.
856  */
857 static int split_mail_stgit_series(struct am_state *state, const char **paths,
858                                         int keep_cr)
859 {
860         const char *series_dir;
861         char *series_dir_buf;
862         FILE *fp;
863         struct argv_array patches = ARGV_ARRAY_INIT;
864         struct strbuf sb = STRBUF_INIT;
865         int ret;
866
867         if (!paths[0] || paths[1])
868                 return error(_("Only one StGIT patch series can be applied at once"));
869
870         series_dir_buf = xstrdup(*paths);
871         series_dir = dirname(series_dir_buf);
872
873         fp = fopen(*paths, "r");
874         if (!fp)
875                 return error(_("could not open '%s' for reading: %s"), *paths,
876                                 strerror(errno));
877
878         while (!strbuf_getline(&sb, fp, '\n')) {
879                 if (*sb.buf == '#')
880                         continue; /* skip comment lines */
881
882                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
883         }
884
885         fclose(fp);
886         strbuf_release(&sb);
887         free(series_dir_buf);
888
889         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
890
891         argv_array_clear(&patches);
892         return ret;
893 }
894
895 /**
896  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
897  * message suitable for parsing with git-mailinfo.
898  */
899 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
900 {
901         struct strbuf sb = STRBUF_INIT;
902
903         while (!strbuf_getline(&sb, in, '\n')) {
904                 const char *str;
905
906                 if (skip_prefix(sb.buf, "# User ", &str))
907                         fprintf(out, "From: %s\n", str);
908                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
909                         unsigned long timestamp;
910                         long tz, tz2;
911                         char *end;
912
913                         errno = 0;
914                         timestamp = strtoul(str, &end, 10);
915                         if (errno)
916                                 return error(_("invalid timestamp"));
917
918                         if (!skip_prefix(end, " ", &str))
919                                 return error(_("invalid Date line"));
920
921                         errno = 0;
922                         tz = strtol(str, &end, 10);
923                         if (errno)
924                                 return error(_("invalid timezone offset"));
925
926                         if (*end)
927                                 return error(_("invalid Date line"));
928
929                         /*
930                          * mercurial's timezone is in seconds west of UTC,
931                          * however git's timezone is in hours + minutes east of
932                          * UTC. Convert it.
933                          */
934                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
935                         if (tz > 0)
936                                 tz2 = -tz2;
937
938                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
939                 } else if (starts_with(sb.buf, "# ")) {
940                         continue;
941                 } else {
942                         fprintf(out, "\n%s\n", sb.buf);
943                         break;
944                 }
945         }
946
947         strbuf_reset(&sb);
948         while (strbuf_fread(&sb, 8192, in) > 0) {
949                 fwrite(sb.buf, 1, sb.len, out);
950                 strbuf_reset(&sb);
951         }
952
953         strbuf_release(&sb);
954         return 0;
955 }
956
957 /**
958  * Splits a list of files/directories into individual email patches. Each path
959  * in `paths` must be a file/directory that is formatted according to
960  * `patch_format`.
961  *
962  * Once split out, the individual email patches will be stored in the state
963  * directory, with each patch's filename being its index, padded to state->prec
964  * digits.
965  *
966  * state->cur will be set to the index of the first mail, and state->last will
967  * be set to the index of the last mail.
968  *
969  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
970  * to disable this behavior, -1 to use the default configured setting.
971  *
972  * Returns 0 on success, -1 on failure.
973  */
974 static int split_mail(struct am_state *state, enum patch_format patch_format,
975                         const char **paths, int keep_cr)
976 {
977         if (keep_cr < 0) {
978                 keep_cr = 0;
979                 git_config_get_bool("am.keepcr", &keep_cr);
980         }
981
982         switch (patch_format) {
983         case PATCH_FORMAT_MBOX:
984                 return split_mail_mbox(state, paths, keep_cr);
985         case PATCH_FORMAT_STGIT:
986                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
987         case PATCH_FORMAT_STGIT_SERIES:
988                 return split_mail_stgit_series(state, paths, keep_cr);
989         case PATCH_FORMAT_HG:
990                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
991         default:
992                 die("BUG: invalid patch_format");
993         }
994         return -1;
995 }
996
997 /**
998  * Setup a new am session for applying patches
999  */
1000 static void am_setup(struct am_state *state, enum patch_format patch_format,
1001                         const char **paths, int keep_cr)
1002 {
1003         unsigned char curr_head[GIT_SHA1_RAWSZ];
1004         const char *str;
1005         struct strbuf sb = STRBUF_INIT;
1006
1007         if (!patch_format)
1008                 patch_format = detect_patch_format(paths);
1009
1010         if (!patch_format) {
1011                 fprintf_ln(stderr, _("Patch format detection failed."));
1012                 exit(128);
1013         }
1014
1015         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
1016                 die_errno(_("failed to create directory '%s'"), state->dir);
1017
1018         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
1019                 am_destroy(state);
1020                 die(_("Failed to split patches."));
1021         }
1022
1023         if (state->rebasing)
1024                 state->threeway = 1;
1025
1026         write_state_bool(state, "threeway", state->threeway);
1027         write_state_bool(state, "quiet", state->quiet);
1028         write_state_bool(state, "sign", state->signoff);
1029         write_state_bool(state, "utf8", state->utf8);
1030
1031         switch (state->keep) {
1032         case KEEP_FALSE:
1033                 str = "f";
1034                 break;
1035         case KEEP_TRUE:
1036                 str = "t";
1037                 break;
1038         case KEEP_NON_PATCH:
1039                 str = "b";
1040                 break;
1041         default:
1042                 die("BUG: invalid value for state->keep");
1043         }
1044
1045         write_state_text(state, "keep", str);
1046         write_state_bool(state, "messageid", state->message_id);
1047
1048         switch (state->scissors) {
1049         case SCISSORS_UNSET:
1050                 str = "";
1051                 break;
1052         case SCISSORS_FALSE:
1053                 str = "f";
1054                 break;
1055         case SCISSORS_TRUE:
1056                 str = "t";
1057                 break;
1058         default:
1059                 die("BUG: invalid value for state->scissors");
1060         }
1061         write_state_text(state, "scissors", str);
1062
1063         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1064         write_state_text(state, "apply-opt", sb.buf);
1065
1066         if (state->rebasing)
1067                 write_state_text(state, "rebasing", "");
1068         else
1069                 write_state_text(state, "applying", "");
1070
1071         if (!get_sha1("HEAD", curr_head)) {
1072                 write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
1073                 if (!state->rebasing)
1074                         update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
1075                                         UPDATE_REFS_DIE_ON_ERR);
1076         } else {
1077                 write_state_text(state, "abort-safety", "");
1078                 if (!state->rebasing)
1079                         delete_ref("ORIG_HEAD", NULL, 0);
1080         }
1081
1082         /*
1083          * NOTE: Since the "next" and "last" files determine if an am_state
1084          * session is in progress, they should be written last.
1085          */
1086
1087         write_state_count(state, "next", state->cur);
1088         write_state_count(state, "last", state->last);
1089
1090         strbuf_release(&sb);
1091 }
1092
1093 /**
1094  * Increments the patch pointer, and cleans am_state for the application of the
1095  * next patch.
1096  */
1097 static void am_next(struct am_state *state)
1098 {
1099         unsigned char head[GIT_SHA1_RAWSZ];
1100
1101         free(state->author_name);
1102         state->author_name = NULL;
1103
1104         free(state->author_email);
1105         state->author_email = NULL;
1106
1107         free(state->author_date);
1108         state->author_date = NULL;
1109
1110         free(state->msg);
1111         state->msg = NULL;
1112         state->msg_len = 0;
1113
1114         unlink(am_path(state, "author-script"));
1115         unlink(am_path(state, "final-commit"));
1116
1117         hashclr(state->orig_commit);
1118         unlink(am_path(state, "original-commit"));
1119
1120         if (!get_sha1("HEAD", head))
1121                 write_state_text(state, "abort-safety", sha1_to_hex(head));
1122         else
1123                 write_state_text(state, "abort-safety", "");
1124
1125         state->cur++;
1126         write_state_count(state, "next", state->cur);
1127 }
1128
1129 /**
1130  * Returns the filename of the current patch email.
1131  */
1132 static const char *msgnum(const struct am_state *state)
1133 {
1134         static struct strbuf sb = STRBUF_INIT;
1135
1136         strbuf_reset(&sb);
1137         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1138
1139         return sb.buf;
1140 }
1141
1142 /**
1143  * Refresh and write index.
1144  */
1145 static void refresh_and_write_cache(void)
1146 {
1147         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1148
1149         hold_locked_index(lock_file, 1);
1150         refresh_cache(REFRESH_QUIET);
1151         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1152                 die(_("unable to write index file"));
1153 }
1154
1155 /**
1156  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1157  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1158  * strbuf is provided, the space-separated list of files that differ will be
1159  * appended to it.
1160  */
1161 static int index_has_changes(struct strbuf *sb)
1162 {
1163         unsigned char head[GIT_SHA1_RAWSZ];
1164         int i;
1165
1166         if (!get_sha1_tree("HEAD", head)) {
1167                 struct diff_options opt;
1168
1169                 diff_setup(&opt);
1170                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1171                 if (!sb)
1172                         DIFF_OPT_SET(&opt, QUICK);
1173                 do_diff_cache(head, &opt);
1174                 diffcore_std(&opt);
1175                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1176                         if (i)
1177                                 strbuf_addch(sb, ' ');
1178                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1179                 }
1180                 diff_flush(&opt);
1181                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1182         } else {
1183                 for (i = 0; sb && i < active_nr; i++) {
1184                         if (i)
1185                                 strbuf_addch(sb, ' ');
1186                         strbuf_addstr(sb, active_cache[i]->name);
1187                 }
1188                 return !!active_nr;
1189         }
1190 }
1191
1192 /**
1193  * Dies with a user-friendly message on how to proceed after resolving the
1194  * problem. This message can be overridden with state->resolvemsg.
1195  */
1196 static void NORETURN die_user_resolve(const struct am_state *state)
1197 {
1198         if (state->resolvemsg) {
1199                 printf_ln("%s", state->resolvemsg);
1200         } else {
1201                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1202
1203                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1204                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1205                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1206         }
1207
1208         exit(128);
1209 }
1210
1211 static void am_signoff(struct strbuf *sb)
1212 {
1213         char *cp;
1214         struct strbuf mine = STRBUF_INIT;
1215
1216         /* Does it end with our own sign-off? */
1217         strbuf_addf(&mine, "\n%s%s\n",
1218                     sign_off_header,
1219                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1220                              getenv("GIT_COMMITTER_EMAIL")));
1221         if (mine.len < sb->len &&
1222             !strcmp(mine.buf, sb->buf + sb->len - mine.len))
1223                 goto exit; /* no need to duplicate */
1224
1225         /* Does it have any Signed-off-by: in the text */
1226         for (cp = sb->buf;
1227              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1228              cp = strchr(cp, '\n')) {
1229                 if (sb->buf == cp || cp[-1] == '\n')
1230                         break;
1231         }
1232
1233         strbuf_addstr(sb, mine.buf + !!cp);
1234 exit:
1235         strbuf_release(&mine);
1236 }
1237
1238 /**
1239  * Appends signoff to the "msg" field of the am_state.
1240  */
1241 static void am_append_signoff(struct am_state *state)
1242 {
1243         struct strbuf sb = STRBUF_INIT;
1244
1245         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1246         am_signoff(&sb);
1247         state->msg = strbuf_detach(&sb, &state->msg_len);
1248 }
1249
1250 /**
1251  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1252  * state->msg will be set to the patch message. state->author_name,
1253  * state->author_email and state->author_date will be set to the patch author's
1254  * name, email and date respectively. The patch body will be written to the
1255  * state directory's "patch" file.
1256  *
1257  * Returns 1 if the patch should be skipped, 0 otherwise.
1258  */
1259 static int parse_mail(struct am_state *state, const char *mail)
1260 {
1261         FILE *fp;
1262         struct strbuf sb = STRBUF_INIT;
1263         struct strbuf msg = STRBUF_INIT;
1264         struct strbuf author_name = STRBUF_INIT;
1265         struct strbuf author_date = STRBUF_INIT;
1266         struct strbuf author_email = STRBUF_INIT;
1267         int ret = 0;
1268         struct mailinfo mi;
1269
1270         setup_mailinfo(&mi);
1271
1272         if (state->utf8)
1273                 mi.metainfo_charset = get_commit_output_encoding();
1274         else
1275                 mi.metainfo_charset = NULL;
1276
1277         switch (state->keep) {
1278         case KEEP_FALSE:
1279                 break;
1280         case KEEP_TRUE:
1281                 mi.keep_subject = 1;
1282                 break;
1283         case KEEP_NON_PATCH:
1284                 mi.keep_non_patch_brackets_in_subject = 1;
1285                 break;
1286         default:
1287                 die("BUG: invalid value for state->keep");
1288         }
1289
1290         if (state->message_id)
1291                 mi.add_message_id = 1;
1292
1293         switch (state->scissors) {
1294         case SCISSORS_UNSET:
1295                 break;
1296         case SCISSORS_FALSE:
1297                 mi.use_scissors = 0;
1298                 break;
1299         case SCISSORS_TRUE:
1300                 mi.use_scissors = 1;
1301                 break;
1302         default:
1303                 die("BUG: invalid value for state->scissors");
1304         }
1305
1306         mi.input = fopen(mail, "r");
1307         if (!mi.input)
1308                 die("could not open input");
1309         mi.output = fopen(am_path(state, "info"), "w");
1310         if (!mi.output)
1311                 die("could not open output 'info'");
1312         if (mailinfo(&mi, am_path(state, "msg"), am_path(state, "patch")))
1313                 die("could not parse patch");
1314
1315         fclose(mi.input);
1316         fclose(mi.output);
1317
1318         /* Extract message and author information */
1319         fp = xfopen(am_path(state, "info"), "r");
1320         while (!strbuf_getline(&sb, fp, '\n')) {
1321                 const char *x;
1322
1323                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1324                         if (msg.len)
1325                                 strbuf_addch(&msg, '\n');
1326                         strbuf_addstr(&msg, x);
1327                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1328                         strbuf_addstr(&author_name, x);
1329                 else if (skip_prefix(sb.buf, "Email: ", &x))
1330                         strbuf_addstr(&author_email, x);
1331                 else if (skip_prefix(sb.buf, "Date: ", &x))
1332                         strbuf_addstr(&author_date, x);
1333         }
1334         fclose(fp);
1335
1336         /* Skip pine's internal folder data */
1337         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1338                 ret = 1;
1339                 goto finish;
1340         }
1341
1342         if (is_empty_file(am_path(state, "patch"))) {
1343                 printf_ln(_("Patch is empty. Was it split wrong?"));
1344                 die_user_resolve(state);
1345         }
1346
1347         strbuf_addstr(&msg, "\n\n");
1348         strbuf_addbuf(&msg, &mi.log_message);
1349         strbuf_stripspace(&msg, 0);
1350
1351         if (state->signoff)
1352                 am_signoff(&msg);
1353
1354         assert(!state->author_name);
1355         state->author_name = strbuf_detach(&author_name, NULL);
1356
1357         assert(!state->author_email);
1358         state->author_email = strbuf_detach(&author_email, NULL);
1359
1360         assert(!state->author_date);
1361         state->author_date = strbuf_detach(&author_date, NULL);
1362
1363         assert(!state->msg);
1364         state->msg = strbuf_detach(&msg, &state->msg_len);
1365
1366 finish:
1367         strbuf_release(&msg);
1368         strbuf_release(&author_date);
1369         strbuf_release(&author_email);
1370         strbuf_release(&author_name);
1371         strbuf_release(&sb);
1372         clear_mailinfo(&mi);
1373         return ret;
1374 }
1375
1376 /**
1377  * Sets commit_id to the commit hash where the mail was generated from.
1378  * Returns 0 on success, -1 on failure.
1379  */
1380 static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
1381 {
1382         struct strbuf sb = STRBUF_INIT;
1383         FILE *fp = xfopen(mail, "r");
1384         const char *x;
1385
1386         if (strbuf_getline(&sb, fp, '\n'))
1387                 return -1;
1388
1389         if (!skip_prefix(sb.buf, "From ", &x))
1390                 return -1;
1391
1392         if (get_sha1_hex(x, commit_id) < 0)
1393                 return -1;
1394
1395         strbuf_release(&sb);
1396         fclose(fp);
1397         return 0;
1398 }
1399
1400 /**
1401  * Sets state->msg, state->author_name, state->author_email, state->author_date
1402  * to the commit's respective info.
1403  */
1404 static void get_commit_info(struct am_state *state, struct commit *commit)
1405 {
1406         const char *buffer, *ident_line, *author_date, *msg;
1407         size_t ident_len;
1408         struct ident_split ident_split;
1409         struct strbuf sb = STRBUF_INIT;
1410
1411         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1412
1413         ident_line = find_commit_header(buffer, "author", &ident_len);
1414
1415         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1416                 strbuf_add(&sb, ident_line, ident_len);
1417                 die(_("invalid ident line: %s"), sb.buf);
1418         }
1419
1420         assert(!state->author_name);
1421         if (ident_split.name_begin) {
1422                 strbuf_add(&sb, ident_split.name_begin,
1423                         ident_split.name_end - ident_split.name_begin);
1424                 state->author_name = strbuf_detach(&sb, NULL);
1425         } else
1426                 state->author_name = xstrdup("");
1427
1428         assert(!state->author_email);
1429         if (ident_split.mail_begin) {
1430                 strbuf_add(&sb, ident_split.mail_begin,
1431                         ident_split.mail_end - ident_split.mail_begin);
1432                 state->author_email = strbuf_detach(&sb, NULL);
1433         } else
1434                 state->author_email = xstrdup("");
1435
1436         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1437         strbuf_addstr(&sb, author_date);
1438         assert(!state->author_date);
1439         state->author_date = strbuf_detach(&sb, NULL);
1440
1441         assert(!state->msg);
1442         msg = strstr(buffer, "\n\n");
1443         if (!msg)
1444                 die(_("unable to parse commit %s"), oid_to_hex(&commit->object.oid));
1445         state->msg = xstrdup(msg + 2);
1446         state->msg_len = strlen(state->msg);
1447 }
1448
1449 /**
1450  * Writes `commit` as a patch to the state directory's "patch" file.
1451  */
1452 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1453 {
1454         struct rev_info rev_info;
1455         FILE *fp;
1456
1457         fp = xfopen(am_path(state, "patch"), "w");
1458         init_revisions(&rev_info, NULL);
1459         rev_info.diff = 1;
1460         rev_info.abbrev = 0;
1461         rev_info.disable_stdin = 1;
1462         rev_info.show_root_diff = 1;
1463         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1464         rev_info.no_commit_id = 1;
1465         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1466         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1467         rev_info.diffopt.use_color = 0;
1468         rev_info.diffopt.file = fp;
1469         rev_info.diffopt.close_file = 1;
1470         add_pending_object(&rev_info, &commit->object, "");
1471         diff_setup_done(&rev_info.diffopt);
1472         log_tree_commit(&rev_info, commit);
1473 }
1474
1475 /**
1476  * Writes the diff of the index against HEAD as a patch to the state
1477  * directory's "patch" file.
1478  */
1479 static void write_index_patch(const struct am_state *state)
1480 {
1481         struct tree *tree;
1482         unsigned char head[GIT_SHA1_RAWSZ];
1483         struct rev_info rev_info;
1484         FILE *fp;
1485
1486         if (!get_sha1_tree("HEAD", head))
1487                 tree = lookup_tree(head);
1488         else
1489                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1490
1491         fp = xfopen(am_path(state, "patch"), "w");
1492         init_revisions(&rev_info, NULL);
1493         rev_info.diff = 1;
1494         rev_info.disable_stdin = 1;
1495         rev_info.no_commit_id = 1;
1496         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1497         rev_info.diffopt.use_color = 0;
1498         rev_info.diffopt.file = fp;
1499         rev_info.diffopt.close_file = 1;
1500         add_pending_object(&rev_info, &tree->object, "");
1501         diff_setup_done(&rev_info.diffopt);
1502         run_diff_index(&rev_info, 1);
1503 }
1504
1505 /**
1506  * Like parse_mail(), but parses the mail by looking up its commit ID
1507  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1508  * of patches.
1509  *
1510  * state->orig_commit will be set to the original commit ID.
1511  *
1512  * Will always return 0 as the patch should never be skipped.
1513  */
1514 static int parse_mail_rebase(struct am_state *state, const char *mail)
1515 {
1516         struct commit *commit;
1517         unsigned char commit_sha1[GIT_SHA1_RAWSZ];
1518
1519         if (get_mail_commit_sha1(commit_sha1, mail) < 0)
1520                 die(_("could not parse %s"), mail);
1521
1522         commit = lookup_commit_or_die(commit_sha1, mail);
1523
1524         get_commit_info(state, commit);
1525
1526         write_commit_patch(state, commit);
1527
1528         hashcpy(state->orig_commit, commit_sha1);
1529         write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
1530
1531         return 0;
1532 }
1533
1534 /**
1535  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1536  * `index_file` is not NULL, the patch will be applied to that index.
1537  */
1538 static int run_apply(const struct am_state *state, const char *index_file)
1539 {
1540         struct child_process cp = CHILD_PROCESS_INIT;
1541
1542         cp.git_cmd = 1;
1543
1544         if (index_file)
1545                 argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
1546
1547         /*
1548          * If we are allowed to fall back on 3-way merge, don't give false
1549          * errors during the initial attempt.
1550          */
1551         if (state->threeway && !index_file) {
1552                 cp.no_stdout = 1;
1553                 cp.no_stderr = 1;
1554         }
1555
1556         argv_array_push(&cp.args, "apply");
1557
1558         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1559
1560         if (index_file)
1561                 argv_array_push(&cp.args, "--cached");
1562         else
1563                 argv_array_push(&cp.args, "--index");
1564
1565         argv_array_push(&cp.args, am_path(state, "patch"));
1566
1567         if (run_command(&cp))
1568                 return -1;
1569
1570         /* Reload index as git-apply will have modified it. */
1571         discard_cache();
1572         read_cache_from(index_file ? index_file : get_index_file());
1573
1574         return 0;
1575 }
1576
1577 /**
1578  * Builds an index that contains just the blobs needed for a 3way merge.
1579  */
1580 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1581 {
1582         struct child_process cp = CHILD_PROCESS_INIT;
1583
1584         cp.git_cmd = 1;
1585         argv_array_push(&cp.args, "apply");
1586         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1587         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1588         argv_array_push(&cp.args, am_path(state, "patch"));
1589
1590         if (run_command(&cp))
1591                 return -1;
1592
1593         return 0;
1594 }
1595
1596 /**
1597  * Do the three-way merge using fake ancestor, his tree constructed
1598  * from the fake ancestor and the postimage of the patch, and our
1599  * state.
1600  */
1601 static int run_fallback_merge_recursive(const struct am_state *state,
1602                                         unsigned char *orig_tree,
1603                                         unsigned char *our_tree,
1604                                         unsigned char *his_tree)
1605 {
1606         struct child_process cp = CHILD_PROCESS_INIT;
1607         int status;
1608
1609         cp.git_cmd = 1;
1610
1611         argv_array_pushf(&cp.env_array, "GITHEAD_%s=%.*s",
1612                          sha1_to_hex(his_tree), linelen(state->msg), state->msg);
1613         if (state->quiet)
1614                 argv_array_push(&cp.env_array, "GIT_MERGE_VERBOSITY=0");
1615
1616         argv_array_push(&cp.args, "merge-recursive");
1617         argv_array_push(&cp.args, sha1_to_hex(orig_tree));
1618         argv_array_push(&cp.args, "--");
1619         argv_array_push(&cp.args, sha1_to_hex(our_tree));
1620         argv_array_push(&cp.args, sha1_to_hex(his_tree));
1621
1622         status = run_command(&cp) ? (-1) : 0;
1623         discard_cache();
1624         read_cache();
1625         return status;
1626 }
1627
1628 /**
1629  * Attempt a threeway merge, using index_path as the temporary index.
1630  */
1631 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1632 {
1633         unsigned char orig_tree[GIT_SHA1_RAWSZ], his_tree[GIT_SHA1_RAWSZ],
1634                       our_tree[GIT_SHA1_RAWSZ];
1635
1636         if (get_sha1("HEAD", our_tree) < 0)
1637                 hashcpy(our_tree, EMPTY_TREE_SHA1_BIN);
1638
1639         if (build_fake_ancestor(state, index_path))
1640                 return error("could not build fake ancestor");
1641
1642         discard_cache();
1643         read_cache_from(index_path);
1644
1645         if (write_index_as_tree(orig_tree, &the_index, index_path, 0, NULL))
1646                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1647
1648         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1649
1650         if (!state->quiet) {
1651                 /*
1652                  * List paths that needed 3-way fallback, so that the user can
1653                  * review them with extra care to spot mismerges.
1654                  */
1655                 struct rev_info rev_info;
1656                 const char *diff_filter_str = "--diff-filter=AM";
1657
1658                 init_revisions(&rev_info, NULL);
1659                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1660                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1, rev_info.prefix);
1661                 add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
1662                 diff_setup_done(&rev_info.diffopt);
1663                 run_diff_index(&rev_info, 1);
1664         }
1665
1666         if (run_apply(state, index_path))
1667                 return error(_("Did you hand edit your patch?\n"
1668                                 "It does not apply to blobs recorded in its index."));
1669
1670         if (write_index_as_tree(his_tree, &the_index, index_path, 0, NULL))
1671                 return error("could not write tree");
1672
1673         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1674
1675         discard_cache();
1676         read_cache();
1677
1678         /*
1679          * This is not so wrong. Depending on which base we picked, orig_tree
1680          * may be wildly different from ours, but his_tree has the same set of
1681          * wildly different changes in parts the patch did not touch, so
1682          * recursive ends up canceling them, saying that we reverted all those
1683          * changes.
1684          */
1685
1686         if (run_fallback_merge_recursive(state, orig_tree, our_tree, his_tree)) {
1687                 rerere(state->allow_rerere_autoupdate);
1688                 return error(_("Failed to merge in the changes."));
1689         }
1690
1691         return 0;
1692 }
1693
1694 /**
1695  * Commits the current index with state->msg as the commit message and
1696  * state->author_name, state->author_email and state->author_date as the author
1697  * information.
1698  */
1699 static void do_commit(const struct am_state *state)
1700 {
1701         unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
1702                       commit[GIT_SHA1_RAWSZ];
1703         unsigned char *ptr;
1704         struct commit_list *parents = NULL;
1705         const char *reflog_msg, *author;
1706         struct strbuf sb = STRBUF_INIT;
1707
1708         if (run_hook_le(NULL, "pre-applypatch", NULL))
1709                 exit(1);
1710
1711         if (write_cache_as_tree(tree, 0, NULL))
1712                 die(_("git write-tree failed to write a tree"));
1713
1714         if (!get_sha1_commit("HEAD", parent)) {
1715                 ptr = parent;
1716                 commit_list_insert(lookup_commit(parent), &parents);
1717         } else {
1718                 ptr = NULL;
1719                 say(state, stderr, _("applying to an empty history"));
1720         }
1721
1722         author = fmt_ident(state->author_name, state->author_email,
1723                         state->ignore_date ? NULL : state->author_date,
1724                         IDENT_STRICT);
1725
1726         if (state->committer_date_is_author_date)
1727                 setenv("GIT_COMMITTER_DATE",
1728                         state->ignore_date ? "" : state->author_date, 1);
1729
1730         if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
1731                                 author, state->sign_commit))
1732                 die(_("failed to write commit object"));
1733
1734         reflog_msg = getenv("GIT_REFLOG_ACTION");
1735         if (!reflog_msg)
1736                 reflog_msg = "am";
1737
1738         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1739                         state->msg);
1740
1741         update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
1742
1743         if (state->rebasing) {
1744                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1745
1746                 assert(!is_null_sha1(state->orig_commit));
1747                 fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
1748                 fprintf(fp, "%s\n", sha1_to_hex(commit));
1749                 fclose(fp);
1750         }
1751
1752         run_hook_le(NULL, "post-applypatch", NULL);
1753
1754         strbuf_release(&sb);
1755 }
1756
1757 /**
1758  * Validates the am_state for resuming -- the "msg" and authorship fields must
1759  * be filled up.
1760  */
1761 static void validate_resume_state(const struct am_state *state)
1762 {
1763         if (!state->msg)
1764                 die(_("cannot resume: %s does not exist."),
1765                         am_path(state, "final-commit"));
1766
1767         if (!state->author_name || !state->author_email || !state->author_date)
1768                 die(_("cannot resume: %s does not exist."),
1769                         am_path(state, "author-script"));
1770 }
1771
1772 /**
1773  * Interactively prompt the user on whether the current patch should be
1774  * applied.
1775  *
1776  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1777  * skip it.
1778  */
1779 static int do_interactive(struct am_state *state)
1780 {
1781         assert(state->msg);
1782
1783         if (!isatty(0))
1784                 die(_("cannot be interactive without stdin connected to a terminal."));
1785
1786         for (;;) {
1787                 const char *reply;
1788
1789                 puts(_("Commit Body is:"));
1790                 puts("--------------------------");
1791                 printf("%s", state->msg);
1792                 puts("--------------------------");
1793
1794                 /*
1795                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1796                  * in your translation. The program will only accept English
1797                  * input at this point.
1798                  */
1799                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1800
1801                 if (!reply) {
1802                         continue;
1803                 } else if (*reply == 'y' || *reply == 'Y') {
1804                         return 0;
1805                 } else if (*reply == 'a' || *reply == 'A') {
1806                         state->interactive = 0;
1807                         return 0;
1808                 } else if (*reply == 'n' || *reply == 'N') {
1809                         return 1;
1810                 } else if (*reply == 'e' || *reply == 'E') {
1811                         struct strbuf msg = STRBUF_INIT;
1812
1813                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1814                                 free(state->msg);
1815                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1816                         }
1817                         strbuf_release(&msg);
1818                 } else if (*reply == 'v' || *reply == 'V') {
1819                         const char *pager = git_pager(1);
1820                         struct child_process cp = CHILD_PROCESS_INIT;
1821
1822                         if (!pager)
1823                                 pager = "cat";
1824                         prepare_pager_args(&cp, pager);
1825                         argv_array_push(&cp.args, am_path(state, "patch"));
1826                         run_command(&cp);
1827                 }
1828         }
1829 }
1830
1831 /**
1832  * Applies all queued mail.
1833  *
1834  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1835  * well as the state directory's "patch" file is used as-is for applying the
1836  * patch and committing it.
1837  */
1838 static void am_run(struct am_state *state, int resume)
1839 {
1840         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1841         struct strbuf sb = STRBUF_INIT;
1842
1843         unlink(am_path(state, "dirtyindex"));
1844
1845         refresh_and_write_cache();
1846
1847         if (index_has_changes(&sb)) {
1848                 write_state_bool(state, "dirtyindex", 1);
1849                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1850         }
1851
1852         strbuf_release(&sb);
1853
1854         while (state->cur <= state->last) {
1855                 const char *mail = am_path(state, msgnum(state));
1856                 int apply_status;
1857
1858                 if (!file_exists(mail))
1859                         goto next;
1860
1861                 if (resume) {
1862                         validate_resume_state(state);
1863                 } else {
1864                         int skip;
1865
1866                         if (state->rebasing)
1867                                 skip = parse_mail_rebase(state, mail);
1868                         else
1869                                 skip = parse_mail(state, mail);
1870
1871                         if (skip)
1872                                 goto next; /* mail should be skipped */
1873
1874                         write_author_script(state);
1875                         write_commit_msg(state);
1876                 }
1877
1878                 if (state->interactive && do_interactive(state))
1879                         goto next;
1880
1881                 if (run_applypatch_msg_hook(state))
1882                         exit(1);
1883
1884                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1885
1886                 apply_status = run_apply(state, NULL);
1887
1888                 if (apply_status && state->threeway) {
1889                         struct strbuf sb = STRBUF_INIT;
1890
1891                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1892                         apply_status = fall_back_threeway(state, sb.buf);
1893                         strbuf_release(&sb);
1894
1895                         /*
1896                          * Applying the patch to an earlier tree and merging
1897                          * the result may have produced the same tree as ours.
1898                          */
1899                         if (!apply_status && !index_has_changes(NULL)) {
1900                                 say(state, stdout, _("No changes -- Patch already applied."));
1901                                 goto next;
1902                         }
1903                 }
1904
1905                 if (apply_status) {
1906                         int advice_amworkdir = 1;
1907
1908                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1909                                 linelen(state->msg), state->msg);
1910
1911                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1912
1913                         if (advice_amworkdir)
1914                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1915                                                 am_path(state, "patch"));
1916
1917                         die_user_resolve(state);
1918                 }
1919
1920                 do_commit(state);
1921
1922 next:
1923                 am_next(state);
1924
1925                 if (resume)
1926                         am_load(state);
1927                 resume = 0;
1928         }
1929
1930         if (!is_empty_file(am_path(state, "rewritten"))) {
1931                 assert(state->rebasing);
1932                 copy_notes_for_rebase(state);
1933                 run_post_rewrite_hook(state);
1934         }
1935
1936         /*
1937          * In rebasing mode, it's up to the caller to take care of
1938          * housekeeping.
1939          */
1940         if (!state->rebasing) {
1941                 am_destroy(state);
1942                 close_all_packs();
1943                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1944         }
1945 }
1946
1947 /**
1948  * Resume the current am session after patch application failure. The user did
1949  * all the hard work, and we do not have to do any patch application. Just
1950  * trust and commit what the user has in the index and working tree.
1951  */
1952 static void am_resolve(struct am_state *state)
1953 {
1954         validate_resume_state(state);
1955
1956         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1957
1958         if (!index_has_changes(NULL)) {
1959                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1960                         "If there is nothing left to stage, chances are that something else\n"
1961                         "already introduced the same changes; you might want to skip this patch."));
1962                 die_user_resolve(state);
1963         }
1964
1965         if (unmerged_cache()) {
1966                 printf_ln(_("You still have unmerged paths in your index.\n"
1967                         "Did you forget to use 'git add'?"));
1968                 die_user_resolve(state);
1969         }
1970
1971         if (state->interactive) {
1972                 write_index_patch(state);
1973                 if (do_interactive(state))
1974                         goto next;
1975         }
1976
1977         rerere(0);
1978
1979         do_commit(state);
1980
1981 next:
1982         am_next(state);
1983         am_load(state);
1984         am_run(state, 0);
1985 }
1986
1987 /**
1988  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1989  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1990  * failure.
1991  */
1992 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1993 {
1994         struct lock_file *lock_file;
1995         struct unpack_trees_options opts;
1996         struct tree_desc t[2];
1997
1998         if (parse_tree(head) || parse_tree(remote))
1999                 return -1;
2000
2001         lock_file = xcalloc(1, sizeof(struct lock_file));
2002         hold_locked_index(lock_file, 1);
2003
2004         refresh_cache(REFRESH_QUIET);
2005
2006         memset(&opts, 0, sizeof(opts));
2007         opts.head_idx = 1;
2008         opts.src_index = &the_index;
2009         opts.dst_index = &the_index;
2010         opts.update = 1;
2011         opts.merge = 1;
2012         opts.reset = reset;
2013         opts.fn = twoway_merge;
2014         init_tree_desc(&t[0], head->buffer, head->size);
2015         init_tree_desc(&t[1], remote->buffer, remote->size);
2016
2017         if (unpack_trees(2, t, &opts)) {
2018                 rollback_lock_file(lock_file);
2019                 return -1;
2020         }
2021
2022         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2023                 die(_("unable to write new index file"));
2024
2025         return 0;
2026 }
2027
2028 /**
2029  * Merges a tree into the index. The index's stat info will take precedence
2030  * over the merged tree's. Returns 0 on success, -1 on failure.
2031  */
2032 static int merge_tree(struct tree *tree)
2033 {
2034         struct lock_file *lock_file;
2035         struct unpack_trees_options opts;
2036         struct tree_desc t[1];
2037
2038         if (parse_tree(tree))
2039                 return -1;
2040
2041         lock_file = xcalloc(1, sizeof(struct lock_file));
2042         hold_locked_index(lock_file, 1);
2043
2044         memset(&opts, 0, sizeof(opts));
2045         opts.head_idx = 1;
2046         opts.src_index = &the_index;
2047         opts.dst_index = &the_index;
2048         opts.merge = 1;
2049         opts.fn = oneway_merge;
2050         init_tree_desc(&t[0], tree->buffer, tree->size);
2051
2052         if (unpack_trees(1, t, &opts)) {
2053                 rollback_lock_file(lock_file);
2054                 return -1;
2055         }
2056
2057         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2058                 die(_("unable to write new index file"));
2059
2060         return 0;
2061 }
2062
2063 /**
2064  * Clean the index without touching entries that are not modified between
2065  * `head` and `remote`.
2066  */
2067 static int clean_index(const unsigned char *head, const unsigned char *remote)
2068 {
2069         struct tree *head_tree, *remote_tree, *index_tree;
2070         unsigned char index[GIT_SHA1_RAWSZ];
2071
2072         head_tree = parse_tree_indirect(head);
2073         if (!head_tree)
2074                 return error(_("Could not parse object '%s'."), sha1_to_hex(head));
2075
2076         remote_tree = parse_tree_indirect(remote);
2077         if (!remote_tree)
2078                 return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
2079
2080         read_cache_unmerged();
2081
2082         if (fast_forward_to(head_tree, head_tree, 1))
2083                 return -1;
2084
2085         if (write_cache_as_tree(index, 0, NULL))
2086                 return -1;
2087
2088         index_tree = parse_tree_indirect(index);
2089         if (!index_tree)
2090                 return error(_("Could not parse object '%s'."), sha1_to_hex(index));
2091
2092         if (fast_forward_to(index_tree, remote_tree, 0))
2093                 return -1;
2094
2095         if (merge_tree(remote_tree))
2096                 return -1;
2097
2098         remove_branch_state();
2099
2100         return 0;
2101 }
2102
2103 /**
2104  * Resets rerere's merge resolution metadata.
2105  */
2106 static void am_rerere_clear(void)
2107 {
2108         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2109         rerere_clear(&merge_rr);
2110         string_list_clear(&merge_rr, 1);
2111 }
2112
2113 /**
2114  * Resume the current am session by skipping the current patch.
2115  */
2116 static void am_skip(struct am_state *state)
2117 {
2118         unsigned char head[GIT_SHA1_RAWSZ];
2119
2120         am_rerere_clear();
2121
2122         if (get_sha1("HEAD", head))
2123                 hashcpy(head, EMPTY_TREE_SHA1_BIN);
2124
2125         if (clean_index(head, head))
2126                 die(_("failed to clean index"));
2127
2128         am_next(state);
2129         am_load(state);
2130         am_run(state, 0);
2131 }
2132
2133 /**
2134  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2135  *
2136  * It is not safe to reset HEAD when:
2137  * 1. git-am previously failed because the index was dirty.
2138  * 2. HEAD has moved since git-am previously failed.
2139  */
2140 static int safe_to_abort(const struct am_state *state)
2141 {
2142         struct strbuf sb = STRBUF_INIT;
2143         unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
2144
2145         if (file_exists(am_path(state, "dirtyindex")))
2146                 return 0;
2147
2148         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2149                 if (get_sha1_hex(sb.buf, abort_safety))
2150                         die(_("could not parse %s"), am_path(state, "abort_safety"));
2151         } else
2152                 hashclr(abort_safety);
2153
2154         if (get_sha1("HEAD", head))
2155                 hashclr(head);
2156
2157         if (!hashcmp(head, abort_safety))
2158                 return 1;
2159
2160         error(_("You seem to have moved HEAD since the last 'am' failure.\n"
2161                 "Not rewinding to ORIG_HEAD"));
2162
2163         return 0;
2164 }
2165
2166 /**
2167  * Aborts the current am session if it is safe to do so.
2168  */
2169 static void am_abort(struct am_state *state)
2170 {
2171         unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
2172         int has_curr_head, has_orig_head;
2173         char *curr_branch;
2174
2175         if (!safe_to_abort(state)) {
2176                 am_destroy(state);
2177                 return;
2178         }
2179
2180         am_rerere_clear();
2181
2182         curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
2183         has_curr_head = !is_null_sha1(curr_head);
2184         if (!has_curr_head)
2185                 hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
2186
2187         has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
2188         if (!has_orig_head)
2189                 hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
2190
2191         clean_index(curr_head, orig_head);
2192
2193         if (has_orig_head)
2194                 update_ref("am --abort", "HEAD", orig_head,
2195                                 has_curr_head ? curr_head : NULL, 0,
2196                                 UPDATE_REFS_DIE_ON_ERR);
2197         else if (curr_branch)
2198                 delete_ref(curr_branch, NULL, REF_NODEREF);
2199
2200         free(curr_branch);
2201         am_destroy(state);
2202 }
2203
2204 /**
2205  * parse_options() callback that validates and sets opt->value to the
2206  * PATCH_FORMAT_* enum value corresponding to `arg`.
2207  */
2208 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2209 {
2210         int *opt_value = opt->value;
2211
2212         if (!strcmp(arg, "mbox"))
2213                 *opt_value = PATCH_FORMAT_MBOX;
2214         else if (!strcmp(arg, "stgit"))
2215                 *opt_value = PATCH_FORMAT_STGIT;
2216         else if (!strcmp(arg, "stgit-series"))
2217                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2218         else if (!strcmp(arg, "hg"))
2219                 *opt_value = PATCH_FORMAT_HG;
2220         else
2221                 return error(_("Invalid value for --patch-format: %s"), arg);
2222         return 0;
2223 }
2224
2225 enum resume_mode {
2226         RESUME_FALSE = 0,
2227         RESUME_APPLY,
2228         RESUME_RESOLVED,
2229         RESUME_SKIP,
2230         RESUME_ABORT
2231 };
2232
2233 static int git_am_config(const char *k, const char *v, void *cb)
2234 {
2235         int status;
2236
2237         status = git_gpg_config(k, v, NULL);
2238         if (status)
2239                 return status;
2240
2241         return git_default_config(k, v, NULL);
2242 }
2243
2244 int cmd_am(int argc, const char **argv, const char *prefix)
2245 {
2246         struct am_state state;
2247         int binary = -1;
2248         int keep_cr = -1;
2249         int patch_format = PATCH_FORMAT_UNKNOWN;
2250         enum resume_mode resume = RESUME_FALSE;
2251         int in_progress;
2252
2253         const char * const usage[] = {
2254                 N_("git am [<options>] [(<mbox>|<Maildir>)...]"),
2255                 N_("git am [<options>] (--continue | --skip | --abort)"),
2256                 NULL
2257         };
2258
2259         struct option options[] = {
2260                 OPT_BOOL('i', "interactive", &state.interactive,
2261                         N_("run interactively")),
2262                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2263                         N_("historical option -- no-op")),
2264                 OPT_BOOL('3', "3way", &state.threeway,
2265                         N_("allow fall back on 3way merging if needed")),
2266                 OPT__QUIET(&state.quiet, N_("be quiet")),
2267                 OPT_SET_INT('s', "signoff", &state.signoff,
2268                         N_("add a Signed-off-by line to the commit message"),
2269                         SIGNOFF_EXPLICIT),
2270                 OPT_BOOL('u', "utf8", &state.utf8,
2271                         N_("recode into utf8 (default)")),
2272                 OPT_SET_INT('k', "keep", &state.keep,
2273                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2274                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2275                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2276                 OPT_BOOL('m', "message-id", &state.message_id,
2277                         N_("pass -m flag to git-mailinfo")),
2278                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2279                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2280                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2281                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2282                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2283                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2284                 OPT_BOOL('c', "scissors", &state.scissors,
2285                         N_("strip everything before a scissors line")),
2286                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2287                         N_("pass it through git-apply"),
2288                         0),
2289                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2290                         N_("pass it through git-apply"),
2291                         PARSE_OPT_NOARG),
2292                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2293                         N_("pass it through git-apply"),
2294                         PARSE_OPT_NOARG),
2295                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2296                         N_("pass it through git-apply"),
2297                         0),
2298                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2299                         N_("pass it through git-apply"),
2300                         0),
2301                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2302                         N_("pass it through git-apply"),
2303                         0),
2304                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2305                         N_("pass it through git-apply"),
2306                         0),
2307                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2308                         N_("pass it through git-apply"),
2309                         0),
2310                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2311                         N_("format the patch(es) are in"),
2312                         parse_opt_patchformat),
2313                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2314                         N_("pass it through git-apply"),
2315                         PARSE_OPT_NOARG),
2316                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2317                         N_("override error message when patch failure occurs")),
2318                 OPT_CMDMODE(0, "continue", &resume,
2319                         N_("continue applying patches after resolving a conflict"),
2320                         RESUME_RESOLVED),
2321                 OPT_CMDMODE('r', "resolved", &resume,
2322                         N_("synonyms for --continue"),
2323                         RESUME_RESOLVED),
2324                 OPT_CMDMODE(0, "skip", &resume,
2325                         N_("skip the current patch"),
2326                         RESUME_SKIP),
2327                 OPT_CMDMODE(0, "abort", &resume,
2328                         N_("restore the original branch and abort the patching operation."),
2329                         RESUME_ABORT),
2330                 OPT_BOOL(0, "committer-date-is-author-date",
2331                         &state.committer_date_is_author_date,
2332                         N_("lie about committer date")),
2333                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2334                         N_("use current timestamp for author date")),
2335                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2336                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2337                   N_("GPG-sign commits"),
2338                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2339                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2340                         N_("(internal use for git-rebase)")),
2341                 OPT_END()
2342         };
2343
2344         git_config(git_am_config, NULL);
2345
2346         am_state_init(&state, git_path("rebase-apply"));
2347
2348         in_progress = am_in_progress(&state);
2349         if (in_progress)
2350                 am_load(&state);
2351
2352         argc = parse_options(argc, argv, prefix, options, usage, 0);
2353
2354         if (binary >= 0)
2355                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2356                                 "it will be removed. Please do not use it anymore."));
2357
2358         /* Ensure a valid committer ident can be constructed */
2359         git_committer_info(IDENT_STRICT);
2360
2361         if (read_index_preload(&the_index, NULL) < 0)
2362                 die(_("failed to read the index"));
2363
2364         if (in_progress) {
2365                 /*
2366                  * Catch user error to feed us patches when there is a session
2367                  * in progress:
2368                  *
2369                  * 1. mbox path(s) are provided on the command-line.
2370                  * 2. stdin is not a tty: the user is trying to feed us a patch
2371                  *    from standard input. This is somewhat unreliable -- stdin
2372                  *    could be /dev/null for example and the caller did not
2373                  *    intend to feed us a patch but wanted to continue
2374                  *    unattended.
2375                  */
2376                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2377                         die(_("previous rebase directory %s still exists but mbox given."),
2378                                 state.dir);
2379
2380                 if (resume == RESUME_FALSE)
2381                         resume = RESUME_APPLY;
2382
2383                 if (state.signoff == SIGNOFF_EXPLICIT)
2384                         am_append_signoff(&state);
2385         } else {
2386                 struct argv_array paths = ARGV_ARRAY_INIT;
2387                 int i;
2388
2389                 /*
2390                  * Handle stray state directory in the independent-run case. In
2391                  * the --rebasing case, it is up to the caller to take care of
2392                  * stray directories.
2393                  */
2394                 if (file_exists(state.dir) && !state.rebasing) {
2395                         if (resume == RESUME_ABORT) {
2396                                 am_destroy(&state);
2397                                 am_state_release(&state);
2398                                 return 0;
2399                         }
2400
2401                         die(_("Stray %s directory found.\n"
2402                                 "Use \"git am --abort\" to remove it."),
2403                                 state.dir);
2404                 }
2405
2406                 if (resume)
2407                         die(_("Resolve operation not in progress, we are not resuming."));
2408
2409                 for (i = 0; i < argc; i++) {
2410                         if (is_absolute_path(argv[i]) || !prefix)
2411                                 argv_array_push(&paths, argv[i]);
2412                         else
2413                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2414                 }
2415
2416                 am_setup(&state, patch_format, paths.argv, keep_cr);
2417
2418                 argv_array_clear(&paths);
2419         }
2420
2421         switch (resume) {
2422         case RESUME_FALSE:
2423                 am_run(&state, 0);
2424                 break;
2425         case RESUME_APPLY:
2426                 am_run(&state, 1);
2427                 break;
2428         case RESUME_RESOLVED:
2429                 am_resolve(&state);
2430                 break;
2431         case RESUME_SKIP:
2432                 am_skip(&state);
2433                 break;
2434         case RESUME_ABORT:
2435                 am_abort(&state);
2436                 break;
2437         default:
2438                 die("BUG: invalid resume value");
2439         }
2440
2441         am_state_release(&state);
2442
2443         return 0;
2444 }