Sync with 2.5.2
[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
31 /**
32  * Returns 1 if the file is empty or does not exist, 0 otherwise.
33  */
34 static int is_empty_file(const char *filename)
35 {
36         struct stat st;
37
38         if (stat(filename, &st) < 0) {
39                 if (errno == ENOENT)
40                         return 1;
41                 die_errno(_("could not stat %s"), filename);
42         }
43
44         return !st.st_size;
45 }
46
47 /**
48  * Like strbuf_getline(), but treats both '\n' and "\r\n" as line terminators.
49  */
50 static int strbuf_getline_crlf(struct strbuf *sb, FILE *fp)
51 {
52         if (strbuf_getwholeline(sb, fp, '\n'))
53                 return EOF;
54         if (sb->buf[sb->len - 1] == '\n') {
55                 strbuf_setlen(sb, sb->len - 1);
56                 if (sb->len > 0 && sb->buf[sb->len - 1] == '\r')
57                         strbuf_setlen(sb, sb->len - 1);
58         }
59         return 0;
60 }
61
62 /**
63  * Returns the length of the first line of msg.
64  */
65 static int linelen(const char *msg)
66 {
67         return strchrnul(msg, '\n') - msg;
68 }
69
70 /**
71  * Returns true if `str` consists of only whitespace, false otherwise.
72  */
73 static int str_isspace(const char *str)
74 {
75         for (; *str; str++)
76                 if (!isspace(*str))
77                         return 0;
78
79         return 1;
80 }
81
82 enum patch_format {
83         PATCH_FORMAT_UNKNOWN = 0,
84         PATCH_FORMAT_MBOX,
85         PATCH_FORMAT_STGIT,
86         PATCH_FORMAT_STGIT_SERIES,
87         PATCH_FORMAT_HG
88 };
89
90 enum keep_type {
91         KEEP_FALSE = 0,
92         KEEP_TRUE,      /* pass -k flag to git-mailinfo */
93         KEEP_NON_PATCH  /* pass -b flag to git-mailinfo */
94 };
95
96 enum scissors_type {
97         SCISSORS_UNSET = -1,
98         SCISSORS_FALSE = 0,  /* pass --no-scissors to git-mailinfo */
99         SCISSORS_TRUE        /* pass --scissors to git-mailinfo */
100 };
101
102 enum signoff_type {
103         SIGNOFF_FALSE = 0,
104         SIGNOFF_TRUE = 1,
105         SIGNOFF_EXPLICIT /* --signoff was set on the command-line */
106 };
107
108 struct am_state {
109         /* state directory path */
110         char *dir;
111
112         /* current and last patch numbers, 1-indexed */
113         int cur;
114         int last;
115
116         /* commit metadata and message */
117         char *author_name;
118         char *author_email;
119         char *author_date;
120         char *msg;
121         size_t msg_len;
122
123         /* when --rebasing, records the original commit the patch came from */
124         unsigned char orig_commit[GIT_SHA1_RAWSZ];
125
126         /* number of digits in patch filename */
127         int prec;
128
129         /* various operating modes and command line options */
130         int interactive;
131         int threeway;
132         int quiet;
133         int signoff; /* enum signoff_type */
134         int utf8;
135         int keep; /* enum keep_type */
136         int message_id;
137         int scissors; /* enum scissors_type */
138         struct argv_array git_apply_opts;
139         const char *resolvemsg;
140         int committer_date_is_author_date;
141         int ignore_date;
142         int allow_rerere_autoupdate;
143         const char *sign_commit;
144         int rebasing;
145 };
146
147 /**
148  * Initializes am_state with the default values. The state directory is set to
149  * dir.
150  */
151 static void am_state_init(struct am_state *state, const char *dir)
152 {
153         int gpgsign;
154
155         memset(state, 0, sizeof(*state));
156
157         assert(dir);
158         state->dir = xstrdup(dir);
159
160         state->prec = 4;
161
162         git_config_get_bool("am.threeway", &state->threeway);
163
164         state->utf8 = 1;
165
166         git_config_get_bool("am.messageid", &state->message_id);
167
168         state->scissors = SCISSORS_UNSET;
169
170         argv_array_init(&state->git_apply_opts);
171
172         if (!git_config_get_bool("commit.gpgsign", &gpgsign))
173                 state->sign_commit = gpgsign ? "" : NULL;
174 }
175
176 /**
177  * Releases memory allocated by an am_state.
178  */
179 static void am_state_release(struct am_state *state)
180 {
181         free(state->dir);
182         free(state->author_name);
183         free(state->author_email);
184         free(state->author_date);
185         free(state->msg);
186         argv_array_clear(&state->git_apply_opts);
187 }
188
189 /**
190  * Returns path relative to the am_state directory.
191  */
192 static inline const char *am_path(const struct am_state *state, const char *path)
193 {
194         return mkpath("%s/%s", state->dir, path);
195 }
196
197 /**
198  * For convenience to call write_file()
199  */
200 static int write_state_text(const struct am_state *state,
201                             const char *name, const char *string)
202 {
203         return write_file(am_path(state, name), "%s", string);
204 }
205
206 static int write_state_count(const struct am_state *state,
207                              const char *name, int value)
208 {
209         return write_file(am_path(state, name), "%d", value);
210 }
211
212 static int write_state_bool(const struct am_state *state,
213                             const char *name, int value)
214 {
215         return write_state_text(state, name, value ? "t" : "f");
216 }
217
218 /**
219  * If state->quiet is false, calls fprintf(fp, fmt, ...), and appends a newline
220  * at the end.
221  */
222 static void say(const struct am_state *state, FILE *fp, const char *fmt, ...)
223 {
224         va_list ap;
225
226         va_start(ap, fmt);
227         if (!state->quiet) {
228                 vfprintf(fp, fmt, ap);
229                 putc('\n', fp);
230         }
231         va_end(ap);
232 }
233
234 /**
235  * Returns 1 if there is an am session in progress, 0 otherwise.
236  */
237 static int am_in_progress(const struct am_state *state)
238 {
239         struct stat st;
240
241         if (lstat(state->dir, &st) < 0 || !S_ISDIR(st.st_mode))
242                 return 0;
243         if (lstat(am_path(state, "last"), &st) || !S_ISREG(st.st_mode))
244                 return 0;
245         if (lstat(am_path(state, "next"), &st) || !S_ISREG(st.st_mode))
246                 return 0;
247         return 1;
248 }
249
250 /**
251  * Reads the contents of `file` in the `state` directory into `sb`. Returns the
252  * number of bytes read on success, -1 if the file does not exist. If `trim` is
253  * set, trailing whitespace will be removed.
254  */
255 static int read_state_file(struct strbuf *sb, const struct am_state *state,
256                         const char *file, int trim)
257 {
258         strbuf_reset(sb);
259
260         if (strbuf_read_file(sb, am_path(state, file), 0) >= 0) {
261                 if (trim)
262                         strbuf_trim(sb);
263
264                 return sb->len;
265         }
266
267         if (errno == ENOENT)
268                 return -1;
269
270         die_errno(_("could not read '%s'"), am_path(state, file));
271 }
272
273 /**
274  * Reads a KEY=VALUE shell variable assignment from `fp`, returning the VALUE
275  * as a newly-allocated string. VALUE must be a quoted string, and the KEY must
276  * match `key`. Returns NULL on failure.
277  *
278  * This is used by read_author_script() to read the GIT_AUTHOR_* variables from
279  * the author-script.
280  */
281 static char *read_shell_var(FILE *fp, const char *key)
282 {
283         struct strbuf sb = STRBUF_INIT;
284         const char *str;
285
286         if (strbuf_getline(&sb, fp, '\n'))
287                 goto fail;
288
289         if (!skip_prefix(sb.buf, key, &str))
290                 goto fail;
291
292         if (!skip_prefix(str, "=", &str))
293                 goto fail;
294
295         strbuf_remove(&sb, 0, str - sb.buf);
296
297         str = sq_dequote(sb.buf);
298         if (!str)
299                 goto fail;
300
301         return strbuf_detach(&sb, NULL);
302
303 fail:
304         strbuf_release(&sb);
305         return NULL;
306 }
307
308 /**
309  * Reads and parses the state directory's "author-script" file, and sets
310  * state->author_name, state->author_email and state->author_date accordingly.
311  * Returns 0 on success, -1 if the file could not be parsed.
312  *
313  * The author script is of the format:
314  *
315  *      GIT_AUTHOR_NAME='$author_name'
316  *      GIT_AUTHOR_EMAIL='$author_email'
317  *      GIT_AUTHOR_DATE='$author_date'
318  *
319  * where $author_name, $author_email and $author_date are quoted. We are strict
320  * with our parsing, as the file was meant to be eval'd in the old git-am.sh
321  * script, and thus if the file differs from what this function expects, it is
322  * better to bail out than to do something that the user does not expect.
323  */
324 static int read_author_script(struct am_state *state)
325 {
326         const char *filename = am_path(state, "author-script");
327         FILE *fp;
328
329         assert(!state->author_name);
330         assert(!state->author_email);
331         assert(!state->author_date);
332
333         fp = fopen(filename, "r");
334         if (!fp) {
335                 if (errno == ENOENT)
336                         return 0;
337                 die_errno(_("could not open '%s' for reading"), filename);
338         }
339
340         state->author_name = read_shell_var(fp, "GIT_AUTHOR_NAME");
341         if (!state->author_name) {
342                 fclose(fp);
343                 return -1;
344         }
345
346         state->author_email = read_shell_var(fp, "GIT_AUTHOR_EMAIL");
347         if (!state->author_email) {
348                 fclose(fp);
349                 return -1;
350         }
351
352         state->author_date = read_shell_var(fp, "GIT_AUTHOR_DATE");
353         if (!state->author_date) {
354                 fclose(fp);
355                 return -1;
356         }
357
358         if (fgetc(fp) != EOF) {
359                 fclose(fp);
360                 return -1;
361         }
362
363         fclose(fp);
364         return 0;
365 }
366
367 /**
368  * Saves state->author_name, state->author_email and state->author_date in the
369  * state directory's "author-script" file.
370  */
371 static void write_author_script(const struct am_state *state)
372 {
373         struct strbuf sb = STRBUF_INIT;
374
375         strbuf_addstr(&sb, "GIT_AUTHOR_NAME=");
376         sq_quote_buf(&sb, state->author_name);
377         strbuf_addch(&sb, '\n');
378
379         strbuf_addstr(&sb, "GIT_AUTHOR_EMAIL=");
380         sq_quote_buf(&sb, state->author_email);
381         strbuf_addch(&sb, '\n');
382
383         strbuf_addstr(&sb, "GIT_AUTHOR_DATE=");
384         sq_quote_buf(&sb, state->author_date);
385         strbuf_addch(&sb, '\n');
386
387         write_state_text(state, "author-script", sb.buf);
388
389         strbuf_release(&sb);
390 }
391
392 /**
393  * Reads the commit message from the state directory's "final-commit" file,
394  * setting state->msg to its contents and state->msg_len to the length of its
395  * contents in bytes.
396  *
397  * Returns 0 on success, -1 if the file does not exist.
398  */
399 static int read_commit_msg(struct am_state *state)
400 {
401         struct strbuf sb = STRBUF_INIT;
402
403         assert(!state->msg);
404
405         if (read_state_file(&sb, state, "final-commit", 0) < 0) {
406                 strbuf_release(&sb);
407                 return -1;
408         }
409
410         state->msg = strbuf_detach(&sb, &state->msg_len);
411         return 0;
412 }
413
414 /**
415  * Saves state->msg in the state directory's "final-commit" file.
416  */
417 static void write_commit_msg(const struct am_state *state)
418 {
419         int fd;
420         const char *filename = am_path(state, "final-commit");
421
422         fd = xopen(filename, O_WRONLY | O_CREAT, 0666);
423         if (write_in_full(fd, state->msg, state->msg_len) < 0)
424                 die_errno(_("could not write to %s"), filename);
425         close(fd);
426 }
427
428 /**
429  * Loads state from disk.
430  */
431 static void am_load(struct am_state *state)
432 {
433         struct strbuf sb = STRBUF_INIT;
434
435         if (read_state_file(&sb, state, "next", 1) < 0)
436                 die("BUG: state file 'next' does not exist");
437         state->cur = strtol(sb.buf, NULL, 10);
438
439         if (read_state_file(&sb, state, "last", 1) < 0)
440                 die("BUG: state file 'last' does not exist");
441         state->last = strtol(sb.buf, NULL, 10);
442
443         if (read_author_script(state) < 0)
444                 die(_("could not parse author script"));
445
446         read_commit_msg(state);
447
448         if (read_state_file(&sb, state, "original-commit", 1) < 0)
449                 hashclr(state->orig_commit);
450         else if (get_sha1_hex(sb.buf, state->orig_commit) < 0)
451                 die(_("could not parse %s"), am_path(state, "original-commit"));
452
453         read_state_file(&sb, state, "threeway", 1);
454         state->threeway = !strcmp(sb.buf, "t");
455
456         read_state_file(&sb, state, "quiet", 1);
457         state->quiet = !strcmp(sb.buf, "t");
458
459         read_state_file(&sb, state, "sign", 1);
460         state->signoff = !strcmp(sb.buf, "t");
461
462         read_state_file(&sb, state, "utf8", 1);
463         state->utf8 = !strcmp(sb.buf, "t");
464
465         read_state_file(&sb, state, "keep", 1);
466         if (!strcmp(sb.buf, "t"))
467                 state->keep = KEEP_TRUE;
468         else if (!strcmp(sb.buf, "b"))
469                 state->keep = KEEP_NON_PATCH;
470         else
471                 state->keep = KEEP_FALSE;
472
473         read_state_file(&sb, state, "messageid", 1);
474         state->message_id = !strcmp(sb.buf, "t");
475
476         read_state_file(&sb, state, "scissors", 1);
477         if (!strcmp(sb.buf, "t"))
478                 state->scissors = SCISSORS_TRUE;
479         else if (!strcmp(sb.buf, "f"))
480                 state->scissors = SCISSORS_FALSE;
481         else
482                 state->scissors = SCISSORS_UNSET;
483
484         read_state_file(&sb, state, "apply-opt", 1);
485         argv_array_clear(&state->git_apply_opts);
486         if (sq_dequote_to_argv_array(sb.buf, &state->git_apply_opts) < 0)
487                 die(_("could not parse %s"), am_path(state, "apply-opt"));
488
489         state->rebasing = !!file_exists(am_path(state, "rebasing"));
490
491         strbuf_release(&sb);
492 }
493
494 /**
495  * Removes the am_state directory, forcefully terminating the current am
496  * session.
497  */
498 static void am_destroy(const struct am_state *state)
499 {
500         struct strbuf sb = STRBUF_INIT;
501
502         strbuf_addstr(&sb, state->dir);
503         remove_dir_recursively(&sb, 0);
504         strbuf_release(&sb);
505 }
506
507 /**
508  * Runs applypatch-msg hook. Returns its exit code.
509  */
510 static int run_applypatch_msg_hook(struct am_state *state)
511 {
512         int ret;
513
514         assert(state->msg);
515         ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
516
517         if (!ret) {
518                 free(state->msg);
519                 state->msg = NULL;
520                 if (read_commit_msg(state) < 0)
521                         die(_("'%s' was deleted by the applypatch-msg hook"),
522                                 am_path(state, "final-commit"));
523         }
524
525         return ret;
526 }
527
528 /**
529  * Runs post-rewrite hook. Returns it exit code.
530  */
531 static int run_post_rewrite_hook(const struct am_state *state)
532 {
533         struct child_process cp = CHILD_PROCESS_INIT;
534         const char *hook = find_hook("post-rewrite");
535         int ret;
536
537         if (!hook)
538                 return 0;
539
540         argv_array_push(&cp.args, hook);
541         argv_array_push(&cp.args, "rebase");
542
543         cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
544         cp.stdout_to_stderr = 1;
545
546         ret = run_command(&cp);
547
548         close(cp.in);
549         return ret;
550 }
551
552 /**
553  * Reads the state directory's "rewritten" file, and copies notes from the old
554  * commits listed in the file to their rewritten commits.
555  *
556  * Returns 0 on success, -1 on failure.
557  */
558 static int copy_notes_for_rebase(const struct am_state *state)
559 {
560         struct notes_rewrite_cfg *c;
561         struct strbuf sb = STRBUF_INIT;
562         const char *invalid_line = _("Malformed input line: '%s'.");
563         const char *msg = "Notes added by 'git rebase'";
564         FILE *fp;
565         int ret = 0;
566
567         assert(state->rebasing);
568
569         c = init_copy_notes_for_rewrite("rebase");
570         if (!c)
571                 return 0;
572
573         fp = xfopen(am_path(state, "rewritten"), "r");
574
575         while (!strbuf_getline(&sb, fp, '\n')) {
576                 unsigned char from_obj[GIT_SHA1_RAWSZ], to_obj[GIT_SHA1_RAWSZ];
577
578                 if (sb.len != GIT_SHA1_HEXSZ * 2 + 1) {
579                         ret = error(invalid_line, sb.buf);
580                         goto finish;
581                 }
582
583                 if (get_sha1_hex(sb.buf, from_obj)) {
584                         ret = error(invalid_line, sb.buf);
585                         goto finish;
586                 }
587
588                 if (sb.buf[GIT_SHA1_HEXSZ] != ' ') {
589                         ret = error(invalid_line, sb.buf);
590                         goto finish;
591                 }
592
593                 if (get_sha1_hex(sb.buf + GIT_SHA1_HEXSZ + 1, to_obj)) {
594                         ret = error(invalid_line, sb.buf);
595                         goto finish;
596                 }
597
598                 if (copy_note_for_rewrite(c, from_obj, to_obj))
599                         ret = error(_("Failed to copy notes from '%s' to '%s'"),
600                                         sha1_to_hex(from_obj), sha1_to_hex(to_obj));
601         }
602
603 finish:
604         finish_copy_notes_for_rewrite(c, msg);
605         fclose(fp);
606         strbuf_release(&sb);
607         return ret;
608 }
609
610 /**
611  * Determines if the file looks like a piece of RFC2822 mail by grabbing all
612  * non-indented lines and checking if they look like they begin with valid
613  * header field names.
614  *
615  * Returns 1 if the file looks like a piece of mail, 0 otherwise.
616  */
617 static int is_mail(FILE *fp)
618 {
619         const char *header_regex = "^[!-9;-~]+:";
620         struct strbuf sb = STRBUF_INIT;
621         regex_t regex;
622         int ret = 1;
623
624         if (fseek(fp, 0L, SEEK_SET))
625                 die_errno(_("fseek failed"));
626
627         if (regcomp(&regex, header_regex, REG_NOSUB | REG_EXTENDED))
628                 die("invalid pattern: %s", header_regex);
629
630         while (!strbuf_getline_crlf(&sb, fp)) {
631                 if (!sb.len)
632                         break; /* End of header */
633
634                 /* Ignore indented folded lines */
635                 if (*sb.buf == '\t' || *sb.buf == ' ')
636                         continue;
637
638                 /* It's a header if it matches header_regex */
639                 if (regexec(&regex, sb.buf, 0, NULL, 0)) {
640                         ret = 0;
641                         goto done;
642                 }
643         }
644
645 done:
646         regfree(&regex);
647         strbuf_release(&sb);
648         return ret;
649 }
650
651 /**
652  * Attempts to detect the patch_format of the patches contained in `paths`,
653  * returning the PATCH_FORMAT_* enum value. Returns PATCH_FORMAT_UNKNOWN if
654  * detection fails.
655  */
656 static int detect_patch_format(const char **paths)
657 {
658         enum patch_format ret = PATCH_FORMAT_UNKNOWN;
659         struct strbuf l1 = STRBUF_INIT;
660         struct strbuf l2 = STRBUF_INIT;
661         struct strbuf l3 = STRBUF_INIT;
662         FILE *fp;
663
664         /*
665          * We default to mbox format if input is from stdin and for directories
666          */
667         if (!*paths || !strcmp(*paths, "-") || is_directory(*paths))
668                 return PATCH_FORMAT_MBOX;
669
670         /*
671          * Otherwise, check the first few lines of the first patch, starting
672          * from the first non-blank line, to try to detect its format.
673          */
674
675         fp = xfopen(*paths, "r");
676
677         while (!strbuf_getline_crlf(&l1, fp)) {
678                 if (l1.len)
679                         break;
680         }
681
682         if (starts_with(l1.buf, "From ") || starts_with(l1.buf, "From: ")) {
683                 ret = PATCH_FORMAT_MBOX;
684                 goto done;
685         }
686
687         if (starts_with(l1.buf, "# This series applies on GIT commit")) {
688                 ret = PATCH_FORMAT_STGIT_SERIES;
689                 goto done;
690         }
691
692         if (!strcmp(l1.buf, "# HG changeset patch")) {
693                 ret = PATCH_FORMAT_HG;
694                 goto done;
695         }
696
697         strbuf_reset(&l2);
698         strbuf_getline_crlf(&l2, fp);
699         strbuf_reset(&l3);
700         strbuf_getline_crlf(&l3, fp);
701
702         /*
703          * If the second line is empty and the third is a From, Author or Date
704          * entry, this is likely an StGit patch.
705          */
706         if (l1.len && !l2.len &&
707                 (starts_with(l3.buf, "From:") ||
708                  starts_with(l3.buf, "Author:") ||
709                  starts_with(l3.buf, "Date:"))) {
710                 ret = PATCH_FORMAT_STGIT;
711                 goto done;
712         }
713
714         if (l1.len && is_mail(fp)) {
715                 ret = PATCH_FORMAT_MBOX;
716                 goto done;
717         }
718
719 done:
720         fclose(fp);
721         strbuf_release(&l1);
722         return ret;
723 }
724
725 /**
726  * Splits out individual email patches from `paths`, where each path is either
727  * a mbox file or a Maildir. Returns 0 on success, -1 on failure.
728  */
729 static int split_mail_mbox(struct am_state *state, const char **paths, int keep_cr)
730 {
731         struct child_process cp = CHILD_PROCESS_INIT;
732         struct strbuf last = STRBUF_INIT;
733
734         cp.git_cmd = 1;
735         argv_array_push(&cp.args, "mailsplit");
736         argv_array_pushf(&cp.args, "-d%d", state->prec);
737         argv_array_pushf(&cp.args, "-o%s", state->dir);
738         argv_array_push(&cp.args, "-b");
739         if (keep_cr)
740                 argv_array_push(&cp.args, "--keep-cr");
741         argv_array_push(&cp.args, "--");
742         argv_array_pushv(&cp.args, paths);
743
744         if (capture_command(&cp, &last, 8))
745                 return -1;
746
747         state->cur = 1;
748         state->last = strtol(last.buf, NULL, 10);
749
750         return 0;
751 }
752
753 /**
754  * Callback signature for split_mail_conv(). The foreign patch should be
755  * read from `in`, and the converted patch (in RFC2822 mail format) should be
756  * written to `out`. Return 0 on success, or -1 on failure.
757  */
758 typedef int (*mail_conv_fn)(FILE *out, FILE *in, int keep_cr);
759
760 /**
761  * Calls `fn` for each file in `paths` to convert the foreign patch to the
762  * RFC2822 mail format suitable for parsing with git-mailinfo.
763  *
764  * Returns 0 on success, -1 on failure.
765  */
766 static int split_mail_conv(mail_conv_fn fn, struct am_state *state,
767                         const char **paths, int keep_cr)
768 {
769         static const char *stdin_only[] = {"-", NULL};
770         int i;
771
772         if (!*paths)
773                 paths = stdin_only;
774
775         for (i = 0; *paths; paths++, i++) {
776                 FILE *in, *out;
777                 const char *mail;
778                 int ret;
779
780                 if (!strcmp(*paths, "-"))
781                         in = stdin;
782                 else
783                         in = fopen(*paths, "r");
784
785                 if (!in)
786                         return error(_("could not open '%s' for reading: %s"),
787                                         *paths, strerror(errno));
788
789                 mail = mkpath("%s/%0*d", state->dir, state->prec, i + 1);
790
791                 out = fopen(mail, "w");
792                 if (!out)
793                         return error(_("could not open '%s' for writing: %s"),
794                                         mail, strerror(errno));
795
796                 ret = fn(out, in, keep_cr);
797
798                 fclose(out);
799                 fclose(in);
800
801                 if (ret)
802                         return error(_("could not parse patch '%s'"), *paths);
803         }
804
805         state->cur = 1;
806         state->last = i;
807         return 0;
808 }
809
810 /**
811  * A split_mail_conv() callback that converts an StGit patch to an RFC2822
812  * message suitable for parsing with git-mailinfo.
813  */
814 static int stgit_patch_to_mail(FILE *out, FILE *in, int keep_cr)
815 {
816         struct strbuf sb = STRBUF_INIT;
817         int subject_printed = 0;
818
819         while (!strbuf_getline(&sb, in, '\n')) {
820                 const char *str;
821
822                 if (str_isspace(sb.buf))
823                         continue;
824                 else if (skip_prefix(sb.buf, "Author:", &str))
825                         fprintf(out, "From:%s\n", str);
826                 else if (starts_with(sb.buf, "From") || starts_with(sb.buf, "Date"))
827                         fprintf(out, "%s\n", sb.buf);
828                 else if (!subject_printed) {
829                         fprintf(out, "Subject: %s\n", sb.buf);
830                         subject_printed = 1;
831                 } else {
832                         fprintf(out, "\n%s\n", sb.buf);
833                         break;
834                 }
835         }
836
837         strbuf_reset(&sb);
838         while (strbuf_fread(&sb, 8192, in) > 0) {
839                 fwrite(sb.buf, 1, sb.len, out);
840                 strbuf_reset(&sb);
841         }
842
843         strbuf_release(&sb);
844         return 0;
845 }
846
847 /**
848  * This function only supports a single StGit series file in `paths`.
849  *
850  * Given an StGit series file, converts the StGit patches in the series into
851  * RFC2822 messages suitable for parsing with git-mailinfo, and queues them in
852  * the state directory.
853  *
854  * Returns 0 on success, -1 on failure.
855  */
856 static int split_mail_stgit_series(struct am_state *state, const char **paths,
857                                         int keep_cr)
858 {
859         const char *series_dir;
860         char *series_dir_buf;
861         FILE *fp;
862         struct argv_array patches = ARGV_ARRAY_INIT;
863         struct strbuf sb = STRBUF_INIT;
864         int ret;
865
866         if (!paths[0] || paths[1])
867                 return error(_("Only one StGIT patch series can be applied at once"));
868
869         series_dir_buf = xstrdup(*paths);
870         series_dir = dirname(series_dir_buf);
871
872         fp = fopen(*paths, "r");
873         if (!fp)
874                 return error(_("could not open '%s' for reading: %s"), *paths,
875                                 strerror(errno));
876
877         while (!strbuf_getline(&sb, fp, '\n')) {
878                 if (*sb.buf == '#')
879                         continue; /* skip comment lines */
880
881                 argv_array_push(&patches, mkpath("%s/%s", series_dir, sb.buf));
882         }
883
884         fclose(fp);
885         strbuf_release(&sb);
886         free(series_dir_buf);
887
888         ret = split_mail_conv(stgit_patch_to_mail, state, patches.argv, keep_cr);
889
890         argv_array_clear(&patches);
891         return ret;
892 }
893
894 /**
895  * A split_patches_conv() callback that converts a mercurial patch to a RFC2822
896  * message suitable for parsing with git-mailinfo.
897  */
898 static int hg_patch_to_mail(FILE *out, FILE *in, int keep_cr)
899 {
900         struct strbuf sb = STRBUF_INIT;
901
902         while (!strbuf_getline(&sb, in, '\n')) {
903                 const char *str;
904
905                 if (skip_prefix(sb.buf, "# User ", &str))
906                         fprintf(out, "From: %s\n", str);
907                 else if (skip_prefix(sb.buf, "# Date ", &str)) {
908                         unsigned long timestamp;
909                         long tz, tz2;
910                         char *end;
911
912                         errno = 0;
913                         timestamp = strtoul(str, &end, 10);
914                         if (errno)
915                                 return error(_("invalid timestamp"));
916
917                         if (!skip_prefix(end, " ", &str))
918                                 return error(_("invalid Date line"));
919
920                         errno = 0;
921                         tz = strtol(str, &end, 10);
922                         if (errno)
923                                 return error(_("invalid timezone offset"));
924
925                         if (*end)
926                                 return error(_("invalid Date line"));
927
928                         /*
929                          * mercurial's timezone is in seconds west of UTC,
930                          * however git's timezone is in hours + minutes east of
931                          * UTC. Convert it.
932                          */
933                         tz2 = labs(tz) / 3600 * 100 + labs(tz) % 3600 / 60;
934                         if (tz > 0)
935                                 tz2 = -tz2;
936
937                         fprintf(out, "Date: %s\n", show_date(timestamp, tz2, DATE_MODE(RFC2822)));
938                 } else if (starts_with(sb.buf, "# ")) {
939                         continue;
940                 } else {
941                         fprintf(out, "\n%s\n", sb.buf);
942                         break;
943                 }
944         }
945
946         strbuf_reset(&sb);
947         while (strbuf_fread(&sb, 8192, in) > 0) {
948                 fwrite(sb.buf, 1, sb.len, out);
949                 strbuf_reset(&sb);
950         }
951
952         strbuf_release(&sb);
953         return 0;
954 }
955
956 /**
957  * Splits a list of files/directories into individual email patches. Each path
958  * in `paths` must be a file/directory that is formatted according to
959  * `patch_format`.
960  *
961  * Once split out, the individual email patches will be stored in the state
962  * directory, with each patch's filename being its index, padded to state->prec
963  * digits.
964  *
965  * state->cur will be set to the index of the first mail, and state->last will
966  * be set to the index of the last mail.
967  *
968  * Set keep_cr to 0 to convert all lines ending with \r\n to end with \n, 1
969  * to disable this behavior, -1 to use the default configured setting.
970  *
971  * Returns 0 on success, -1 on failure.
972  */
973 static int split_mail(struct am_state *state, enum patch_format patch_format,
974                         const char **paths, int keep_cr)
975 {
976         if (keep_cr < 0) {
977                 keep_cr = 0;
978                 git_config_get_bool("am.keepcr", &keep_cr);
979         }
980
981         switch (patch_format) {
982         case PATCH_FORMAT_MBOX:
983                 return split_mail_mbox(state, paths, keep_cr);
984         case PATCH_FORMAT_STGIT:
985                 return split_mail_conv(stgit_patch_to_mail, state, paths, keep_cr);
986         case PATCH_FORMAT_STGIT_SERIES:
987                 return split_mail_stgit_series(state, paths, keep_cr);
988         case PATCH_FORMAT_HG:
989                 return split_mail_conv(hg_patch_to_mail, state, paths, keep_cr);
990         default:
991                 die("BUG: invalid patch_format");
992         }
993         return -1;
994 }
995
996 /**
997  * Setup a new am session for applying patches
998  */
999 static void am_setup(struct am_state *state, enum patch_format patch_format,
1000                         const char **paths, int keep_cr)
1001 {
1002         unsigned char curr_head[GIT_SHA1_RAWSZ];
1003         const char *str;
1004         struct strbuf sb = STRBUF_INIT;
1005
1006         if (!patch_format)
1007                 patch_format = detect_patch_format(paths);
1008
1009         if (!patch_format) {
1010                 fprintf_ln(stderr, _("Patch format detection failed."));
1011                 exit(128);
1012         }
1013
1014         if (mkdir(state->dir, 0777) < 0 && errno != EEXIST)
1015                 die_errno(_("failed to create directory '%s'"), state->dir);
1016
1017         if (split_mail(state, patch_format, paths, keep_cr) < 0) {
1018                 am_destroy(state);
1019                 die(_("Failed to split patches."));
1020         }
1021
1022         if (state->rebasing)
1023                 state->threeway = 1;
1024
1025         write_state_bool(state, "threeway", state->threeway);
1026         write_state_bool(state, "quiet", state->quiet);
1027         write_state_bool(state, "sign", state->signoff);
1028         write_state_bool(state, "utf8", state->utf8);
1029
1030         switch (state->keep) {
1031         case KEEP_FALSE:
1032                 str = "f";
1033                 break;
1034         case KEEP_TRUE:
1035                 str = "t";
1036                 break;
1037         case KEEP_NON_PATCH:
1038                 str = "b";
1039                 break;
1040         default:
1041                 die("BUG: invalid value for state->keep");
1042         }
1043
1044         write_state_text(state, "keep", str);
1045         write_state_bool(state, "messageid", state->message_id);
1046
1047         switch (state->scissors) {
1048         case SCISSORS_UNSET:
1049                 str = "";
1050                 break;
1051         case SCISSORS_FALSE:
1052                 str = "f";
1053                 break;
1054         case SCISSORS_TRUE:
1055                 str = "t";
1056                 break;
1057         default:
1058                 die("BUG: invalid value for state->scissors");
1059         }
1060         write_state_text(state, "scissors", str);
1061
1062         sq_quote_argv(&sb, state->git_apply_opts.argv, 0);
1063         write_state_text(state, "apply-opt", sb.buf);
1064
1065         if (state->rebasing)
1066                 write_state_text(state, "rebasing", "");
1067         else
1068                 write_state_text(state, "applying", "");
1069
1070         if (!get_sha1("HEAD", curr_head)) {
1071                 write_state_text(state, "abort-safety", sha1_to_hex(curr_head));
1072                 if (!state->rebasing)
1073                         update_ref("am", "ORIG_HEAD", curr_head, NULL, 0,
1074                                         UPDATE_REFS_DIE_ON_ERR);
1075         } else {
1076                 write_state_text(state, "abort-safety", "");
1077                 if (!state->rebasing)
1078                         delete_ref("ORIG_HEAD", NULL, 0);
1079         }
1080
1081         /*
1082          * NOTE: Since the "next" and "last" files determine if an am_state
1083          * session is in progress, they should be written last.
1084          */
1085
1086         write_state_count(state, "next", state->cur);
1087         write_state_count(state, "last", state->last);
1088
1089         strbuf_release(&sb);
1090 }
1091
1092 /**
1093  * Increments the patch pointer, and cleans am_state for the application of the
1094  * next patch.
1095  */
1096 static void am_next(struct am_state *state)
1097 {
1098         unsigned char head[GIT_SHA1_RAWSZ];
1099
1100         free(state->author_name);
1101         state->author_name = NULL;
1102
1103         free(state->author_email);
1104         state->author_email = NULL;
1105
1106         free(state->author_date);
1107         state->author_date = NULL;
1108
1109         free(state->msg);
1110         state->msg = NULL;
1111         state->msg_len = 0;
1112
1113         unlink(am_path(state, "author-script"));
1114         unlink(am_path(state, "final-commit"));
1115
1116         hashclr(state->orig_commit);
1117         unlink(am_path(state, "original-commit"));
1118
1119         if (!get_sha1("HEAD", head))
1120                 write_state_text(state, "abort-safety", sha1_to_hex(head));
1121         else
1122                 write_state_text(state, "abort-safety", "");
1123
1124         state->cur++;
1125         write_state_count(state, "next", state->cur);
1126 }
1127
1128 /**
1129  * Returns the filename of the current patch email.
1130  */
1131 static const char *msgnum(const struct am_state *state)
1132 {
1133         static struct strbuf sb = STRBUF_INIT;
1134
1135         strbuf_reset(&sb);
1136         strbuf_addf(&sb, "%0*d", state->prec, state->cur);
1137
1138         return sb.buf;
1139 }
1140
1141 /**
1142  * Refresh and write index.
1143  */
1144 static void refresh_and_write_cache(void)
1145 {
1146         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
1147
1148         hold_locked_index(lock_file, 1);
1149         refresh_cache(REFRESH_QUIET);
1150         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
1151                 die(_("unable to write index file"));
1152 }
1153
1154 /**
1155  * Returns 1 if the index differs from HEAD, 0 otherwise. When on an unborn
1156  * branch, returns 1 if there are entries in the index, 0 otherwise. If an
1157  * strbuf is provided, the space-separated list of files that differ will be
1158  * appended to it.
1159  */
1160 static int index_has_changes(struct strbuf *sb)
1161 {
1162         unsigned char head[GIT_SHA1_RAWSZ];
1163         int i;
1164
1165         if (!get_sha1_tree("HEAD", head)) {
1166                 struct diff_options opt;
1167
1168                 diff_setup(&opt);
1169                 DIFF_OPT_SET(&opt, EXIT_WITH_STATUS);
1170                 if (!sb)
1171                         DIFF_OPT_SET(&opt, QUICK);
1172                 do_diff_cache(head, &opt);
1173                 diffcore_std(&opt);
1174                 for (i = 0; sb && i < diff_queued_diff.nr; i++) {
1175                         if (i)
1176                                 strbuf_addch(sb, ' ');
1177                         strbuf_addstr(sb, diff_queued_diff.queue[i]->two->path);
1178                 }
1179                 diff_flush(&opt);
1180                 return DIFF_OPT_TST(&opt, HAS_CHANGES) != 0;
1181         } else {
1182                 for (i = 0; sb && i < active_nr; i++) {
1183                         if (i)
1184                                 strbuf_addch(sb, ' ');
1185                         strbuf_addstr(sb, active_cache[i]->name);
1186                 }
1187                 return !!active_nr;
1188         }
1189 }
1190
1191 /**
1192  * Dies with a user-friendly message on how to proceed after resolving the
1193  * problem. This message can be overridden with state->resolvemsg.
1194  */
1195 static void NORETURN die_user_resolve(const struct am_state *state)
1196 {
1197         if (state->resolvemsg) {
1198                 printf_ln("%s", state->resolvemsg);
1199         } else {
1200                 const char *cmdline = state->interactive ? "git am -i" : "git am";
1201
1202                 printf_ln(_("When you have resolved this problem, run \"%s --continue\"."), cmdline);
1203                 printf_ln(_("If you prefer to skip this patch, run \"%s --skip\" instead."), cmdline);
1204                 printf_ln(_("To restore the original branch and stop patching, run \"%s --abort\"."), cmdline);
1205         }
1206
1207         exit(128);
1208 }
1209
1210 static void am_signoff(struct strbuf *sb)
1211 {
1212         char *cp;
1213         struct strbuf mine = STRBUF_INIT;
1214
1215         /* Does it end with our own sign-off? */
1216         strbuf_addf(&mine, "\n%s%s\n",
1217                     sign_off_header,
1218                     fmt_name(getenv("GIT_COMMITTER_NAME"),
1219                              getenv("GIT_COMMITTER_EMAIL")));
1220         if (mine.len < sb->len &&
1221             !strcmp(mine.buf, sb->buf + sb->len - mine.len))
1222                 goto exit; /* no need to duplicate */
1223
1224         /* Does it have any Signed-off-by: in the text */
1225         for (cp = sb->buf;
1226              cp && *cp && (cp = strstr(cp, sign_off_header)) != NULL;
1227              cp = strchr(cp, '\n')) {
1228                 if (sb->buf == cp || cp[-1] == '\n')
1229                         break;
1230         }
1231
1232         strbuf_addstr(sb, mine.buf + !!cp);
1233 exit:
1234         strbuf_release(&mine);
1235 }
1236
1237 /**
1238  * Appends signoff to the "msg" field of the am_state.
1239  */
1240 static void am_append_signoff(struct am_state *state)
1241 {
1242         struct strbuf sb = STRBUF_INIT;
1243
1244         strbuf_attach(&sb, state->msg, state->msg_len, state->msg_len);
1245         am_signoff(&sb);
1246         state->msg = strbuf_detach(&sb, &state->msg_len);
1247 }
1248
1249 /**
1250  * Parses `mail` using git-mailinfo, extracting its patch and authorship info.
1251  * state->msg will be set to the patch message. state->author_name,
1252  * state->author_email and state->author_date will be set to the patch author's
1253  * name, email and date respectively. The patch body will be written to the
1254  * state directory's "patch" file.
1255  *
1256  * Returns 1 if the patch should be skipped, 0 otherwise.
1257  */
1258 static int parse_mail(struct am_state *state, const char *mail)
1259 {
1260         FILE *fp;
1261         struct child_process cp = CHILD_PROCESS_INIT;
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
1269         cp.git_cmd = 1;
1270         cp.in = xopen(mail, O_RDONLY, 0);
1271         cp.out = xopen(am_path(state, "info"), O_WRONLY | O_CREAT, 0777);
1272
1273         argv_array_push(&cp.args, "mailinfo");
1274         argv_array_push(&cp.args, state->utf8 ? "-u" : "-n");
1275
1276         switch (state->keep) {
1277         case KEEP_FALSE:
1278                 break;
1279         case KEEP_TRUE:
1280                 argv_array_push(&cp.args, "-k");
1281                 break;
1282         case KEEP_NON_PATCH:
1283                 argv_array_push(&cp.args, "-b");
1284                 break;
1285         default:
1286                 die("BUG: invalid value for state->keep");
1287         }
1288
1289         if (state->message_id)
1290                 argv_array_push(&cp.args, "-m");
1291
1292         switch (state->scissors) {
1293         case SCISSORS_UNSET:
1294                 break;
1295         case SCISSORS_FALSE:
1296                 argv_array_push(&cp.args, "--no-scissors");
1297                 break;
1298         case SCISSORS_TRUE:
1299                 argv_array_push(&cp.args, "--scissors");
1300                 break;
1301         default:
1302                 die("BUG: invalid value for state->scissors");
1303         }
1304
1305         argv_array_push(&cp.args, am_path(state, "msg"));
1306         argv_array_push(&cp.args, am_path(state, "patch"));
1307
1308         if (run_command(&cp) < 0)
1309                 die("could not parse patch");
1310
1311         close(cp.in);
1312         close(cp.out);
1313
1314         /* Extract message and author information */
1315         fp = xfopen(am_path(state, "info"), "r");
1316         while (!strbuf_getline(&sb, fp, '\n')) {
1317                 const char *x;
1318
1319                 if (skip_prefix(sb.buf, "Subject: ", &x)) {
1320                         if (msg.len)
1321                                 strbuf_addch(&msg, '\n');
1322                         strbuf_addstr(&msg, x);
1323                 } else if (skip_prefix(sb.buf, "Author: ", &x))
1324                         strbuf_addstr(&author_name, x);
1325                 else if (skip_prefix(sb.buf, "Email: ", &x))
1326                         strbuf_addstr(&author_email, x);
1327                 else if (skip_prefix(sb.buf, "Date: ", &x))
1328                         strbuf_addstr(&author_date, x);
1329         }
1330         fclose(fp);
1331
1332         /* Skip pine's internal folder data */
1333         if (!strcmp(author_name.buf, "Mail System Internal Data")) {
1334                 ret = 1;
1335                 goto finish;
1336         }
1337
1338         if (is_empty_file(am_path(state, "patch"))) {
1339                 printf_ln(_("Patch is empty. Was it split wrong?"));
1340                 die_user_resolve(state);
1341         }
1342
1343         strbuf_addstr(&msg, "\n\n");
1344         if (strbuf_read_file(&msg, am_path(state, "msg"), 0) < 0)
1345                 die_errno(_("could not read '%s'"), am_path(state, "msg"));
1346         stripspace(&msg, 0);
1347
1348         if (state->signoff)
1349                 am_signoff(&msg);
1350
1351         assert(!state->author_name);
1352         state->author_name = strbuf_detach(&author_name, NULL);
1353
1354         assert(!state->author_email);
1355         state->author_email = strbuf_detach(&author_email, NULL);
1356
1357         assert(!state->author_date);
1358         state->author_date = strbuf_detach(&author_date, NULL);
1359
1360         assert(!state->msg);
1361         state->msg = strbuf_detach(&msg, &state->msg_len);
1362
1363 finish:
1364         strbuf_release(&msg);
1365         strbuf_release(&author_date);
1366         strbuf_release(&author_email);
1367         strbuf_release(&author_name);
1368         strbuf_release(&sb);
1369         return ret;
1370 }
1371
1372 /**
1373  * Sets commit_id to the commit hash where the mail was generated from.
1374  * Returns 0 on success, -1 on failure.
1375  */
1376 static int get_mail_commit_sha1(unsigned char *commit_id, const char *mail)
1377 {
1378         struct strbuf sb = STRBUF_INIT;
1379         FILE *fp = xfopen(mail, "r");
1380         const char *x;
1381
1382         if (strbuf_getline(&sb, fp, '\n'))
1383                 return -1;
1384
1385         if (!skip_prefix(sb.buf, "From ", &x))
1386                 return -1;
1387
1388         if (get_sha1_hex(x, commit_id) < 0)
1389                 return -1;
1390
1391         strbuf_release(&sb);
1392         fclose(fp);
1393         return 0;
1394 }
1395
1396 /**
1397  * Sets state->msg, state->author_name, state->author_email, state->author_date
1398  * to the commit's respective info.
1399  */
1400 static void get_commit_info(struct am_state *state, struct commit *commit)
1401 {
1402         const char *buffer, *ident_line, *author_date, *msg;
1403         size_t ident_len;
1404         struct ident_split ident_split;
1405         struct strbuf sb = STRBUF_INIT;
1406
1407         buffer = logmsg_reencode(commit, NULL, get_commit_output_encoding());
1408
1409         ident_line = find_commit_header(buffer, "author", &ident_len);
1410
1411         if (split_ident_line(&ident_split, ident_line, ident_len) < 0) {
1412                 strbuf_add(&sb, ident_line, ident_len);
1413                 die(_("invalid ident line: %s"), sb.buf);
1414         }
1415
1416         assert(!state->author_name);
1417         if (ident_split.name_begin) {
1418                 strbuf_add(&sb, ident_split.name_begin,
1419                         ident_split.name_end - ident_split.name_begin);
1420                 state->author_name = strbuf_detach(&sb, NULL);
1421         } else
1422                 state->author_name = xstrdup("");
1423
1424         assert(!state->author_email);
1425         if (ident_split.mail_begin) {
1426                 strbuf_add(&sb, ident_split.mail_begin,
1427                         ident_split.mail_end - ident_split.mail_begin);
1428                 state->author_email = strbuf_detach(&sb, NULL);
1429         } else
1430                 state->author_email = xstrdup("");
1431
1432         author_date = show_ident_date(&ident_split, DATE_MODE(NORMAL));
1433         strbuf_addstr(&sb, author_date);
1434         assert(!state->author_date);
1435         state->author_date = strbuf_detach(&sb, NULL);
1436
1437         assert(!state->msg);
1438         msg = strstr(buffer, "\n\n");
1439         if (!msg)
1440                 die(_("unable to parse commit %s"), sha1_to_hex(commit->object.sha1));
1441         state->msg = xstrdup(msg + 2);
1442         state->msg_len = strlen(state->msg);
1443 }
1444
1445 /**
1446  * Writes `commit` as a patch to the state directory's "patch" file.
1447  */
1448 static void write_commit_patch(const struct am_state *state, struct commit *commit)
1449 {
1450         struct rev_info rev_info;
1451         FILE *fp;
1452
1453         fp = xfopen(am_path(state, "patch"), "w");
1454         init_revisions(&rev_info, NULL);
1455         rev_info.diff = 1;
1456         rev_info.abbrev = 0;
1457         rev_info.disable_stdin = 1;
1458         rev_info.show_root_diff = 1;
1459         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1460         rev_info.no_commit_id = 1;
1461         DIFF_OPT_SET(&rev_info.diffopt, BINARY);
1462         DIFF_OPT_SET(&rev_info.diffopt, FULL_INDEX);
1463         rev_info.diffopt.use_color = 0;
1464         rev_info.diffopt.file = fp;
1465         rev_info.diffopt.close_file = 1;
1466         add_pending_object(&rev_info, &commit->object, "");
1467         diff_setup_done(&rev_info.diffopt);
1468         log_tree_commit(&rev_info, commit);
1469 }
1470
1471 /**
1472  * Writes the diff of the index against HEAD as a patch to the state
1473  * directory's "patch" file.
1474  */
1475 static void write_index_patch(const struct am_state *state)
1476 {
1477         struct tree *tree;
1478         unsigned char head[GIT_SHA1_RAWSZ];
1479         struct rev_info rev_info;
1480         FILE *fp;
1481
1482         if (!get_sha1_tree("HEAD", head))
1483                 tree = lookup_tree(head);
1484         else
1485                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1486
1487         fp = xfopen(am_path(state, "patch"), "w");
1488         init_revisions(&rev_info, NULL);
1489         rev_info.diff = 1;
1490         rev_info.disable_stdin = 1;
1491         rev_info.no_commit_id = 1;
1492         rev_info.diffopt.output_format = DIFF_FORMAT_PATCH;
1493         rev_info.diffopt.use_color = 0;
1494         rev_info.diffopt.file = fp;
1495         rev_info.diffopt.close_file = 1;
1496         add_pending_object(&rev_info, &tree->object, "");
1497         diff_setup_done(&rev_info.diffopt);
1498         run_diff_index(&rev_info, 1);
1499 }
1500
1501 /**
1502  * Like parse_mail(), but parses the mail by looking up its commit ID
1503  * directly. This is used in --rebasing mode to bypass git-mailinfo's munging
1504  * of patches.
1505  *
1506  * state->orig_commit will be set to the original commit ID.
1507  *
1508  * Will always return 0 as the patch should never be skipped.
1509  */
1510 static int parse_mail_rebase(struct am_state *state, const char *mail)
1511 {
1512         struct commit *commit;
1513         unsigned char commit_sha1[GIT_SHA1_RAWSZ];
1514
1515         if (get_mail_commit_sha1(commit_sha1, mail) < 0)
1516                 die(_("could not parse %s"), mail);
1517
1518         commit = lookup_commit_or_die(commit_sha1, mail);
1519
1520         get_commit_info(state, commit);
1521
1522         write_commit_patch(state, commit);
1523
1524         hashcpy(state->orig_commit, commit_sha1);
1525         write_state_text(state, "original-commit", sha1_to_hex(commit_sha1));
1526
1527         return 0;
1528 }
1529
1530 /**
1531  * Applies current patch with git-apply. Returns 0 on success, -1 otherwise. If
1532  * `index_file` is not NULL, the patch will be applied to that index.
1533  */
1534 static int run_apply(const struct am_state *state, const char *index_file)
1535 {
1536         struct child_process cp = CHILD_PROCESS_INIT;
1537
1538         cp.git_cmd = 1;
1539
1540         if (index_file)
1541                 argv_array_pushf(&cp.env_array, "GIT_INDEX_FILE=%s", index_file);
1542
1543         /*
1544          * If we are allowed to fall back on 3-way merge, don't give false
1545          * errors during the initial attempt.
1546          */
1547         if (state->threeway && !index_file) {
1548                 cp.no_stdout = 1;
1549                 cp.no_stderr = 1;
1550         }
1551
1552         argv_array_push(&cp.args, "apply");
1553
1554         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1555
1556         if (index_file)
1557                 argv_array_push(&cp.args, "--cached");
1558         else
1559                 argv_array_push(&cp.args, "--index");
1560
1561         argv_array_push(&cp.args, am_path(state, "patch"));
1562
1563         if (run_command(&cp))
1564                 return -1;
1565
1566         /* Reload index as git-apply will have modified it. */
1567         discard_cache();
1568         read_cache_from(index_file ? index_file : get_index_file());
1569
1570         return 0;
1571 }
1572
1573 /**
1574  * Builds an index that contains just the blobs needed for a 3way merge.
1575  */
1576 static int build_fake_ancestor(const struct am_state *state, const char *index_file)
1577 {
1578         struct child_process cp = CHILD_PROCESS_INIT;
1579
1580         cp.git_cmd = 1;
1581         argv_array_push(&cp.args, "apply");
1582         argv_array_pushv(&cp.args, state->git_apply_opts.argv);
1583         argv_array_pushf(&cp.args, "--build-fake-ancestor=%s", index_file);
1584         argv_array_push(&cp.args, am_path(state, "patch"));
1585
1586         if (run_command(&cp))
1587                 return -1;
1588
1589         return 0;
1590 }
1591
1592 /**
1593  * Attempt a threeway merge, using index_path as the temporary index.
1594  */
1595 static int fall_back_threeway(const struct am_state *state, const char *index_path)
1596 {
1597         unsigned char orig_tree[GIT_SHA1_RAWSZ], his_tree[GIT_SHA1_RAWSZ],
1598                       our_tree[GIT_SHA1_RAWSZ];
1599         const unsigned char *bases[1] = {orig_tree};
1600         struct merge_options o;
1601         struct commit *result;
1602         char *his_tree_name;
1603
1604         if (get_sha1("HEAD", our_tree) < 0)
1605                 hashcpy(our_tree, EMPTY_TREE_SHA1_BIN);
1606
1607         if (build_fake_ancestor(state, index_path))
1608                 return error("could not build fake ancestor");
1609
1610         discard_cache();
1611         read_cache_from(index_path);
1612
1613         if (write_index_as_tree(orig_tree, &the_index, index_path, 0, NULL))
1614                 return error(_("Repository lacks necessary blobs to fall back on 3-way merge."));
1615
1616         say(state, stdout, _("Using index info to reconstruct a base tree..."));
1617
1618         if (!state->quiet) {
1619                 /*
1620                  * List paths that needed 3-way fallback, so that the user can
1621                  * review them with extra care to spot mismerges.
1622                  */
1623                 struct rev_info rev_info;
1624                 const char *diff_filter_str = "--diff-filter=AM";
1625
1626                 init_revisions(&rev_info, NULL);
1627                 rev_info.diffopt.output_format = DIFF_FORMAT_NAME_STATUS;
1628                 diff_opt_parse(&rev_info.diffopt, &diff_filter_str, 1);
1629                 add_pending_sha1(&rev_info, "HEAD", our_tree, 0);
1630                 diff_setup_done(&rev_info.diffopt);
1631                 run_diff_index(&rev_info, 1);
1632         }
1633
1634         if (run_apply(state, index_path))
1635                 return error(_("Did you hand edit your patch?\n"
1636                                 "It does not apply to blobs recorded in its index."));
1637
1638         if (write_index_as_tree(his_tree, &the_index, index_path, 0, NULL))
1639                 return error("could not write tree");
1640
1641         say(state, stdout, _("Falling back to patching base and 3-way merge..."));
1642
1643         discard_cache();
1644         read_cache();
1645
1646         /*
1647          * This is not so wrong. Depending on which base we picked, orig_tree
1648          * may be wildly different from ours, but his_tree has the same set of
1649          * wildly different changes in parts the patch did not touch, so
1650          * recursive ends up canceling them, saying that we reverted all those
1651          * changes.
1652          */
1653
1654         init_merge_options(&o);
1655
1656         o.branch1 = "HEAD";
1657         his_tree_name = xstrfmt("%.*s", linelen(state->msg), state->msg);
1658         o.branch2 = his_tree_name;
1659
1660         if (state->quiet)
1661                 o.verbosity = 0;
1662
1663         if (merge_recursive_generic(&o, our_tree, his_tree, 1, bases, &result)) {
1664                 rerere(state->allow_rerere_autoupdate);
1665                 free(his_tree_name);
1666                 return error(_("Failed to merge in the changes."));
1667         }
1668
1669         free(his_tree_name);
1670         return 0;
1671 }
1672
1673 /**
1674  * Commits the current index with state->msg as the commit message and
1675  * state->author_name, state->author_email and state->author_date as the author
1676  * information.
1677  */
1678 static void do_commit(const struct am_state *state)
1679 {
1680         unsigned char tree[GIT_SHA1_RAWSZ], parent[GIT_SHA1_RAWSZ],
1681                       commit[GIT_SHA1_RAWSZ];
1682         unsigned char *ptr;
1683         struct commit_list *parents = NULL;
1684         const char *reflog_msg, *author;
1685         struct strbuf sb = STRBUF_INIT;
1686
1687         if (run_hook_le(NULL, "pre-applypatch", NULL))
1688                 exit(1);
1689
1690         if (write_cache_as_tree(tree, 0, NULL))
1691                 die(_("git write-tree failed to write a tree"));
1692
1693         if (!get_sha1_commit("HEAD", parent)) {
1694                 ptr = parent;
1695                 commit_list_insert(lookup_commit(parent), &parents);
1696         } else {
1697                 ptr = NULL;
1698                 say(state, stderr, _("applying to an empty history"));
1699         }
1700
1701         author = fmt_ident(state->author_name, state->author_email,
1702                         state->ignore_date ? NULL : state->author_date,
1703                         IDENT_STRICT);
1704
1705         if (state->committer_date_is_author_date)
1706                 setenv("GIT_COMMITTER_DATE",
1707                         state->ignore_date ? "" : state->author_date, 1);
1708
1709         if (commit_tree(state->msg, state->msg_len, tree, parents, commit,
1710                                 author, state->sign_commit))
1711                 die(_("failed to write commit object"));
1712
1713         reflog_msg = getenv("GIT_REFLOG_ACTION");
1714         if (!reflog_msg)
1715                 reflog_msg = "am";
1716
1717         strbuf_addf(&sb, "%s: %.*s", reflog_msg, linelen(state->msg),
1718                         state->msg);
1719
1720         update_ref(sb.buf, "HEAD", commit, ptr, 0, UPDATE_REFS_DIE_ON_ERR);
1721
1722         if (state->rebasing) {
1723                 FILE *fp = xfopen(am_path(state, "rewritten"), "a");
1724
1725                 assert(!is_null_sha1(state->orig_commit));
1726                 fprintf(fp, "%s ", sha1_to_hex(state->orig_commit));
1727                 fprintf(fp, "%s\n", sha1_to_hex(commit));
1728                 fclose(fp);
1729         }
1730
1731         run_hook_le(NULL, "post-applypatch", NULL);
1732
1733         strbuf_release(&sb);
1734 }
1735
1736 /**
1737  * Validates the am_state for resuming -- the "msg" and authorship fields must
1738  * be filled up.
1739  */
1740 static void validate_resume_state(const struct am_state *state)
1741 {
1742         if (!state->msg)
1743                 die(_("cannot resume: %s does not exist."),
1744                         am_path(state, "final-commit"));
1745
1746         if (!state->author_name || !state->author_email || !state->author_date)
1747                 die(_("cannot resume: %s does not exist."),
1748                         am_path(state, "author-script"));
1749 }
1750
1751 /**
1752  * Interactively prompt the user on whether the current patch should be
1753  * applied.
1754  *
1755  * Returns 0 if the user chooses to apply the patch, 1 if the user chooses to
1756  * skip it.
1757  */
1758 static int do_interactive(struct am_state *state)
1759 {
1760         assert(state->msg);
1761
1762         if (!isatty(0))
1763                 die(_("cannot be interactive without stdin connected to a terminal."));
1764
1765         for (;;) {
1766                 const char *reply;
1767
1768                 puts(_("Commit Body is:"));
1769                 puts("--------------------------");
1770                 printf("%s", state->msg);
1771                 puts("--------------------------");
1772
1773                 /*
1774                  * TRANSLATORS: Make sure to include [y], [n], [e], [v] and [a]
1775                  * in your translation. The program will only accept English
1776                  * input at this point.
1777                  */
1778                 reply = git_prompt(_("Apply? [y]es/[n]o/[e]dit/[v]iew patch/[a]ccept all: "), PROMPT_ECHO);
1779
1780                 if (!reply) {
1781                         continue;
1782                 } else if (*reply == 'y' || *reply == 'Y') {
1783                         return 0;
1784                 } else if (*reply == 'a' || *reply == 'A') {
1785                         state->interactive = 0;
1786                         return 0;
1787                 } else if (*reply == 'n' || *reply == 'N') {
1788                         return 1;
1789                 } else if (*reply == 'e' || *reply == 'E') {
1790                         struct strbuf msg = STRBUF_INIT;
1791
1792                         if (!launch_editor(am_path(state, "final-commit"), &msg, NULL)) {
1793                                 free(state->msg);
1794                                 state->msg = strbuf_detach(&msg, &state->msg_len);
1795                         }
1796                         strbuf_release(&msg);
1797                 } else if (*reply == 'v' || *reply == 'V') {
1798                         const char *pager = git_pager(1);
1799                         struct child_process cp = CHILD_PROCESS_INIT;
1800
1801                         if (!pager)
1802                                 pager = "cat";
1803                         argv_array_push(&cp.args, pager);
1804                         argv_array_push(&cp.args, am_path(state, "patch"));
1805                         run_command(&cp);
1806                 }
1807         }
1808 }
1809
1810 /**
1811  * Applies all queued mail.
1812  *
1813  * If `resume` is true, we are "resuming". The "msg" and authorship fields, as
1814  * well as the state directory's "patch" file is used as-is for applying the
1815  * patch and committing it.
1816  */
1817 static void am_run(struct am_state *state, int resume)
1818 {
1819         const char *argv_gc_auto[] = {"gc", "--auto", NULL};
1820         struct strbuf sb = STRBUF_INIT;
1821
1822         unlink(am_path(state, "dirtyindex"));
1823
1824         refresh_and_write_cache();
1825
1826         if (index_has_changes(&sb)) {
1827                 write_state_bool(state, "dirtyindex", 1);
1828                 die(_("Dirty index: cannot apply patches (dirty: %s)"), sb.buf);
1829         }
1830
1831         strbuf_release(&sb);
1832
1833         while (state->cur <= state->last) {
1834                 const char *mail = am_path(state, msgnum(state));
1835                 int apply_status;
1836
1837                 if (!file_exists(mail))
1838                         goto next;
1839
1840                 if (resume) {
1841                         validate_resume_state(state);
1842                 } else {
1843                         int skip;
1844
1845                         if (state->rebasing)
1846                                 skip = parse_mail_rebase(state, mail);
1847                         else
1848                                 skip = parse_mail(state, mail);
1849
1850                         if (skip)
1851                                 goto next; /* mail should be skipped */
1852
1853                         write_author_script(state);
1854                         write_commit_msg(state);
1855                 }
1856
1857                 if (state->interactive && do_interactive(state))
1858                         goto next;
1859
1860                 if (run_applypatch_msg_hook(state))
1861                         exit(1);
1862
1863                 say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1864
1865                 apply_status = run_apply(state, NULL);
1866
1867                 if (apply_status && state->threeway) {
1868                         struct strbuf sb = STRBUF_INIT;
1869
1870                         strbuf_addstr(&sb, am_path(state, "patch-merge-index"));
1871                         apply_status = fall_back_threeway(state, sb.buf);
1872                         strbuf_release(&sb);
1873
1874                         /*
1875                          * Applying the patch to an earlier tree and merging
1876                          * the result may have produced the same tree as ours.
1877                          */
1878                         if (!apply_status && !index_has_changes(NULL)) {
1879                                 say(state, stdout, _("No changes -- Patch already applied."));
1880                                 goto next;
1881                         }
1882                 }
1883
1884                 if (apply_status) {
1885                         int advice_amworkdir = 1;
1886
1887                         printf_ln(_("Patch failed at %s %.*s"), msgnum(state),
1888                                 linelen(state->msg), state->msg);
1889
1890                         git_config_get_bool("advice.amworkdir", &advice_amworkdir);
1891
1892                         if (advice_amworkdir)
1893                                 printf_ln(_("The copy of the patch that failed is found in: %s"),
1894                                                 am_path(state, "patch"));
1895
1896                         die_user_resolve(state);
1897                 }
1898
1899                 do_commit(state);
1900
1901 next:
1902                 am_next(state);
1903
1904                 if (resume)
1905                         am_load(state);
1906                 resume = 0;
1907         }
1908
1909         if (!is_empty_file(am_path(state, "rewritten"))) {
1910                 assert(state->rebasing);
1911                 copy_notes_for_rebase(state);
1912                 run_post_rewrite_hook(state);
1913         }
1914
1915         /*
1916          * In rebasing mode, it's up to the caller to take care of
1917          * housekeeping.
1918          */
1919         if (!state->rebasing) {
1920                 am_destroy(state);
1921                 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
1922         }
1923 }
1924
1925 /**
1926  * Resume the current am session after patch application failure. The user did
1927  * all the hard work, and we do not have to do any patch application. Just
1928  * trust and commit what the user has in the index and working tree.
1929  */
1930 static void am_resolve(struct am_state *state)
1931 {
1932         validate_resume_state(state);
1933
1934         say(state, stdout, _("Applying: %.*s"), linelen(state->msg), state->msg);
1935
1936         if (!index_has_changes(NULL)) {
1937                 printf_ln(_("No changes - did you forget to use 'git add'?\n"
1938                         "If there is nothing left to stage, chances are that something else\n"
1939                         "already introduced the same changes; you might want to skip this patch."));
1940                 die_user_resolve(state);
1941         }
1942
1943         if (unmerged_cache()) {
1944                 printf_ln(_("You still have unmerged paths in your index.\n"
1945                         "Did you forget to use 'git add'?"));
1946                 die_user_resolve(state);
1947         }
1948
1949         if (state->interactive) {
1950                 write_index_patch(state);
1951                 if (do_interactive(state))
1952                         goto next;
1953         }
1954
1955         rerere(0);
1956
1957         do_commit(state);
1958
1959 next:
1960         am_next(state);
1961         am_load(state);
1962         am_run(state, 0);
1963 }
1964
1965 /**
1966  * Performs a checkout fast-forward from `head` to `remote`. If `reset` is
1967  * true, any unmerged entries will be discarded. Returns 0 on success, -1 on
1968  * failure.
1969  */
1970 static int fast_forward_to(struct tree *head, struct tree *remote, int reset)
1971 {
1972         struct lock_file *lock_file;
1973         struct unpack_trees_options opts;
1974         struct tree_desc t[2];
1975
1976         if (parse_tree(head) || parse_tree(remote))
1977                 return -1;
1978
1979         lock_file = xcalloc(1, sizeof(struct lock_file));
1980         hold_locked_index(lock_file, 1);
1981
1982         refresh_cache(REFRESH_QUIET);
1983
1984         memset(&opts, 0, sizeof(opts));
1985         opts.head_idx = 1;
1986         opts.src_index = &the_index;
1987         opts.dst_index = &the_index;
1988         opts.update = 1;
1989         opts.merge = 1;
1990         opts.reset = reset;
1991         opts.fn = twoway_merge;
1992         init_tree_desc(&t[0], head->buffer, head->size);
1993         init_tree_desc(&t[1], remote->buffer, remote->size);
1994
1995         if (unpack_trees(2, t, &opts)) {
1996                 rollback_lock_file(lock_file);
1997                 return -1;
1998         }
1999
2000         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2001                 die(_("unable to write new index file"));
2002
2003         return 0;
2004 }
2005
2006 /**
2007  * Merges a tree into the index. The index's stat info will take precedence
2008  * over the merged tree's. Returns 0 on success, -1 on failure.
2009  */
2010 static int merge_tree(struct tree *tree)
2011 {
2012         struct lock_file *lock_file;
2013         struct unpack_trees_options opts;
2014         struct tree_desc t[1];
2015
2016         if (parse_tree(tree))
2017                 return -1;
2018
2019         lock_file = xcalloc(1, sizeof(struct lock_file));
2020         hold_locked_index(lock_file, 1);
2021
2022         memset(&opts, 0, sizeof(opts));
2023         opts.head_idx = 1;
2024         opts.src_index = &the_index;
2025         opts.dst_index = &the_index;
2026         opts.merge = 1;
2027         opts.fn = oneway_merge;
2028         init_tree_desc(&t[0], tree->buffer, tree->size);
2029
2030         if (unpack_trees(1, t, &opts)) {
2031                 rollback_lock_file(lock_file);
2032                 return -1;
2033         }
2034
2035         if (write_locked_index(&the_index, lock_file, COMMIT_LOCK))
2036                 die(_("unable to write new index file"));
2037
2038         return 0;
2039 }
2040
2041 /**
2042  * Clean the index without touching entries that are not modified between
2043  * `head` and `remote`.
2044  */
2045 static int clean_index(const unsigned char *head, const unsigned char *remote)
2046 {
2047         struct tree *head_tree, *remote_tree, *index_tree;
2048         unsigned char index[GIT_SHA1_RAWSZ];
2049
2050         head_tree = parse_tree_indirect(head);
2051         if (!head_tree)
2052                 return error(_("Could not parse object '%s'."), sha1_to_hex(head));
2053
2054         remote_tree = parse_tree_indirect(remote);
2055         if (!remote_tree)
2056                 return error(_("Could not parse object '%s'."), sha1_to_hex(remote));
2057
2058         read_cache_unmerged();
2059
2060         if (fast_forward_to(head_tree, head_tree, 1))
2061                 return -1;
2062
2063         if (write_cache_as_tree(index, 0, NULL))
2064                 return -1;
2065
2066         index_tree = parse_tree_indirect(index);
2067         if (!index_tree)
2068                 return error(_("Could not parse object '%s'."), sha1_to_hex(index));
2069
2070         if (fast_forward_to(index_tree, remote_tree, 0))
2071                 return -1;
2072
2073         if (merge_tree(remote_tree))
2074                 return -1;
2075
2076         remove_branch_state();
2077
2078         return 0;
2079 }
2080
2081 /**
2082  * Resets rerere's merge resolution metadata.
2083  */
2084 static void am_rerere_clear(void)
2085 {
2086         struct string_list merge_rr = STRING_LIST_INIT_DUP;
2087         rerere_clear(&merge_rr);
2088         string_list_clear(&merge_rr, 1);
2089 }
2090
2091 /**
2092  * Resume the current am session by skipping the current patch.
2093  */
2094 static void am_skip(struct am_state *state)
2095 {
2096         unsigned char head[GIT_SHA1_RAWSZ];
2097
2098         am_rerere_clear();
2099
2100         if (get_sha1("HEAD", head))
2101                 hashcpy(head, EMPTY_TREE_SHA1_BIN);
2102
2103         if (clean_index(head, head))
2104                 die(_("failed to clean index"));
2105
2106         am_next(state);
2107         am_load(state);
2108         am_run(state, 0);
2109 }
2110
2111 /**
2112  * Returns true if it is safe to reset HEAD to the ORIG_HEAD, false otherwise.
2113  *
2114  * It is not safe to reset HEAD when:
2115  * 1. git-am previously failed because the index was dirty.
2116  * 2. HEAD has moved since git-am previously failed.
2117  */
2118 static int safe_to_abort(const struct am_state *state)
2119 {
2120         struct strbuf sb = STRBUF_INIT;
2121         unsigned char abort_safety[GIT_SHA1_RAWSZ], head[GIT_SHA1_RAWSZ];
2122
2123         if (file_exists(am_path(state, "dirtyindex")))
2124                 return 0;
2125
2126         if (read_state_file(&sb, state, "abort-safety", 1) > 0) {
2127                 if (get_sha1_hex(sb.buf, abort_safety))
2128                         die(_("could not parse %s"), am_path(state, "abort_safety"));
2129         } else
2130                 hashclr(abort_safety);
2131
2132         if (get_sha1("HEAD", head))
2133                 hashclr(head);
2134
2135         if (!hashcmp(head, abort_safety))
2136                 return 1;
2137
2138         error(_("You seem to have moved HEAD since the last 'am' failure.\n"
2139                 "Not rewinding to ORIG_HEAD"));
2140
2141         return 0;
2142 }
2143
2144 /**
2145  * Aborts the current am session if it is safe to do so.
2146  */
2147 static void am_abort(struct am_state *state)
2148 {
2149         unsigned char curr_head[GIT_SHA1_RAWSZ], orig_head[GIT_SHA1_RAWSZ];
2150         int has_curr_head, has_orig_head;
2151         char *curr_branch;
2152
2153         if (!safe_to_abort(state)) {
2154                 am_destroy(state);
2155                 return;
2156         }
2157
2158         am_rerere_clear();
2159
2160         curr_branch = resolve_refdup("HEAD", 0, curr_head, NULL);
2161         has_curr_head = !is_null_sha1(curr_head);
2162         if (!has_curr_head)
2163                 hashcpy(curr_head, EMPTY_TREE_SHA1_BIN);
2164
2165         has_orig_head = !get_sha1("ORIG_HEAD", orig_head);
2166         if (!has_orig_head)
2167                 hashcpy(orig_head, EMPTY_TREE_SHA1_BIN);
2168
2169         clean_index(curr_head, orig_head);
2170
2171         if (has_orig_head)
2172                 update_ref("am --abort", "HEAD", orig_head,
2173                                 has_curr_head ? curr_head : NULL, 0,
2174                                 UPDATE_REFS_DIE_ON_ERR);
2175         else if (curr_branch)
2176                 delete_ref(curr_branch, NULL, REF_NODEREF);
2177
2178         free(curr_branch);
2179         am_destroy(state);
2180 }
2181
2182 /**
2183  * parse_options() callback that validates and sets opt->value to the
2184  * PATCH_FORMAT_* enum value corresponding to `arg`.
2185  */
2186 static int parse_opt_patchformat(const struct option *opt, const char *arg, int unset)
2187 {
2188         int *opt_value = opt->value;
2189
2190         if (!strcmp(arg, "mbox"))
2191                 *opt_value = PATCH_FORMAT_MBOX;
2192         else if (!strcmp(arg, "stgit"))
2193                 *opt_value = PATCH_FORMAT_STGIT;
2194         else if (!strcmp(arg, "stgit-series"))
2195                 *opt_value = PATCH_FORMAT_STGIT_SERIES;
2196         else if (!strcmp(arg, "hg"))
2197                 *opt_value = PATCH_FORMAT_HG;
2198         else
2199                 return error(_("Invalid value for --patch-format: %s"), arg);
2200         return 0;
2201 }
2202
2203 enum resume_mode {
2204         RESUME_FALSE = 0,
2205         RESUME_APPLY,
2206         RESUME_RESOLVED,
2207         RESUME_SKIP,
2208         RESUME_ABORT
2209 };
2210
2211 int cmd_am(int argc, const char **argv, const char *prefix)
2212 {
2213         struct am_state state;
2214         int binary = -1;
2215         int keep_cr = -1;
2216         int patch_format = PATCH_FORMAT_UNKNOWN;
2217         enum resume_mode resume = RESUME_FALSE;
2218         int in_progress;
2219
2220         const char * const usage[] = {
2221                 N_("git am [options] [(<mbox>|<Maildir>)...]"),
2222                 N_("git am [options] (--continue | --skip | --abort)"),
2223                 NULL
2224         };
2225
2226         struct option options[] = {
2227                 OPT_BOOL('i', "interactive", &state.interactive,
2228                         N_("run interactively")),
2229                 OPT_HIDDEN_BOOL('b', "binary", &binary,
2230                         N_("historical option -- no-op")),
2231                 OPT_BOOL('3', "3way", &state.threeway,
2232                         N_("allow fall back on 3way merging if needed")),
2233                 OPT__QUIET(&state.quiet, N_("be quiet")),
2234                 OPT_SET_INT('s', "signoff", &state.signoff,
2235                         N_("add a Signed-off-by line to the commit message"),
2236                         SIGNOFF_EXPLICIT),
2237                 OPT_BOOL('u', "utf8", &state.utf8,
2238                         N_("recode into utf8 (default)")),
2239                 OPT_SET_INT('k', "keep", &state.keep,
2240                         N_("pass -k flag to git-mailinfo"), KEEP_TRUE),
2241                 OPT_SET_INT(0, "keep-non-patch", &state.keep,
2242                         N_("pass -b flag to git-mailinfo"), KEEP_NON_PATCH),
2243                 OPT_BOOL('m', "message-id", &state.message_id,
2244                         N_("pass -m flag to git-mailinfo")),
2245                 { OPTION_SET_INT, 0, "keep-cr", &keep_cr, NULL,
2246                   N_("pass --keep-cr flag to git-mailsplit for mbox format"),
2247                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 1},
2248                 { OPTION_SET_INT, 0, "no-keep-cr", &keep_cr, NULL,
2249                   N_("do not pass --keep-cr flag to git-mailsplit independent of am.keepcr"),
2250                   PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, 0},
2251                 OPT_BOOL('c', "scissors", &state.scissors,
2252                         N_("strip everything before a scissors line")),
2253                 OPT_PASSTHRU_ARGV(0, "whitespace", &state.git_apply_opts, N_("action"),
2254                         N_("pass it through git-apply"),
2255                         0),
2256                 OPT_PASSTHRU_ARGV(0, "ignore-space-change", &state.git_apply_opts, NULL,
2257                         N_("pass it through git-apply"),
2258                         PARSE_OPT_NOARG),
2259                 OPT_PASSTHRU_ARGV(0, "ignore-whitespace", &state.git_apply_opts, NULL,
2260                         N_("pass it through git-apply"),
2261                         PARSE_OPT_NOARG),
2262                 OPT_PASSTHRU_ARGV(0, "directory", &state.git_apply_opts, N_("root"),
2263                         N_("pass it through git-apply"),
2264                         0),
2265                 OPT_PASSTHRU_ARGV(0, "exclude", &state.git_apply_opts, N_("path"),
2266                         N_("pass it through git-apply"),
2267                         0),
2268                 OPT_PASSTHRU_ARGV(0, "include", &state.git_apply_opts, N_("path"),
2269                         N_("pass it through git-apply"),
2270                         0),
2271                 OPT_PASSTHRU_ARGV('C', NULL, &state.git_apply_opts, N_("n"),
2272                         N_("pass it through git-apply"),
2273                         0),
2274                 OPT_PASSTHRU_ARGV('p', NULL, &state.git_apply_opts, N_("num"),
2275                         N_("pass it through git-apply"),
2276                         0),
2277                 OPT_CALLBACK(0, "patch-format", &patch_format, N_("format"),
2278                         N_("format the patch(es) are in"),
2279                         parse_opt_patchformat),
2280                 OPT_PASSTHRU_ARGV(0, "reject", &state.git_apply_opts, NULL,
2281                         N_("pass it through git-apply"),
2282                         PARSE_OPT_NOARG),
2283                 OPT_STRING(0, "resolvemsg", &state.resolvemsg, NULL,
2284                         N_("override error message when patch failure occurs")),
2285                 OPT_CMDMODE(0, "continue", &resume,
2286                         N_("continue applying patches after resolving a conflict"),
2287                         RESUME_RESOLVED),
2288                 OPT_CMDMODE('r', "resolved", &resume,
2289                         N_("synonyms for --continue"),
2290                         RESUME_RESOLVED),
2291                 OPT_CMDMODE(0, "skip", &resume,
2292                         N_("skip the current patch"),
2293                         RESUME_SKIP),
2294                 OPT_CMDMODE(0, "abort", &resume,
2295                         N_("restore the original branch and abort the patching operation."),
2296                         RESUME_ABORT),
2297                 OPT_BOOL(0, "committer-date-is-author-date",
2298                         &state.committer_date_is_author_date,
2299                         N_("lie about committer date")),
2300                 OPT_BOOL(0, "ignore-date", &state.ignore_date,
2301                         N_("use current timestamp for author date")),
2302                 OPT_RERERE_AUTOUPDATE(&state.allow_rerere_autoupdate),
2303                 { OPTION_STRING, 'S', "gpg-sign", &state.sign_commit, N_("key-id"),
2304                   N_("GPG-sign commits"),
2305                   PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
2306                 OPT_HIDDEN_BOOL(0, "rebasing", &state.rebasing,
2307                         N_("(internal use for git-rebase)")),
2308                 OPT_END()
2309         };
2310
2311         git_config(git_default_config, NULL);
2312
2313         am_state_init(&state, git_path("rebase-apply"));
2314
2315         in_progress = am_in_progress(&state);
2316         if (in_progress)
2317                 am_load(&state);
2318
2319         argc = parse_options(argc, argv, prefix, options, usage, 0);
2320
2321         if (binary >= 0)
2322                 fprintf_ln(stderr, _("The -b/--binary option has been a no-op for long time, and\n"
2323                                 "it will be removed. Please do not use it anymore."));
2324
2325         /* Ensure a valid committer ident can be constructed */
2326         git_committer_info(IDENT_STRICT);
2327
2328         if (read_index_preload(&the_index, NULL) < 0)
2329                 die(_("failed to read the index"));
2330
2331         if (in_progress) {
2332                 /*
2333                  * Catch user error to feed us patches when there is a session
2334                  * in progress:
2335                  *
2336                  * 1. mbox path(s) are provided on the command-line.
2337                  * 2. stdin is not a tty: the user is trying to feed us a patch
2338                  *    from standard input. This is somewhat unreliable -- stdin
2339                  *    could be /dev/null for example and the caller did not
2340                  *    intend to feed us a patch but wanted to continue
2341                  *    unattended.
2342                  */
2343                 if (argc || (resume == RESUME_FALSE && !isatty(0)))
2344                         die(_("previous rebase directory %s still exists but mbox given."),
2345                                 state.dir);
2346
2347                 if (resume == RESUME_FALSE)
2348                         resume = RESUME_APPLY;
2349
2350                 if (state.signoff == SIGNOFF_EXPLICIT)
2351                         am_append_signoff(&state);
2352         } else {
2353                 struct argv_array paths = ARGV_ARRAY_INIT;
2354                 int i;
2355
2356                 /*
2357                  * Handle stray state directory in the independent-run case. In
2358                  * the --rebasing case, it is up to the caller to take care of
2359                  * stray directories.
2360                  */
2361                 if (file_exists(state.dir) && !state.rebasing) {
2362                         if (resume == RESUME_ABORT) {
2363                                 am_destroy(&state);
2364                                 am_state_release(&state);
2365                                 return 0;
2366                         }
2367
2368                         die(_("Stray %s directory found.\n"
2369                                 "Use \"git am --abort\" to remove it."),
2370                                 state.dir);
2371                 }
2372
2373                 if (resume)
2374                         die(_("Resolve operation not in progress, we are not resuming."));
2375
2376                 for (i = 0; i < argc; i++) {
2377                         if (is_absolute_path(argv[i]) || !prefix)
2378                                 argv_array_push(&paths, argv[i]);
2379                         else
2380                                 argv_array_push(&paths, mkpath("%s/%s", prefix, argv[i]));
2381                 }
2382
2383                 am_setup(&state, patch_format, paths.argv, keep_cr);
2384
2385                 argv_array_clear(&paths);
2386         }
2387
2388         switch (resume) {
2389         case RESUME_FALSE:
2390                 am_run(&state, 0);
2391                 break;
2392         case RESUME_APPLY:
2393                 am_run(&state, 1);
2394                 break;
2395         case RESUME_RESOLVED:
2396                 am_resolve(&state);
2397                 break;
2398         case RESUME_SKIP:
2399                 am_skip(&state);
2400                 break;
2401         case RESUME_ABORT:
2402                 am_abort(&state);
2403                 break;
2404         default:
2405                 die("BUG: invalid resume value");
2406         }
2407
2408         am_state_release(&state);
2409
2410         return 0;
2411 }