Merge branch 'kg/packed-ref-cache-fix'
[git] / mailinfo.c
1 #include "cache.h"
2 #include "config.h"
3 #include "utf8.h"
4 #include "strbuf.h"
5 #include "mailinfo.h"
6
7 static void cleanup_space(struct strbuf *sb)
8 {
9         size_t pos, cnt;
10         for (pos = 0; pos < sb->len; pos++) {
11                 if (isspace(sb->buf[pos])) {
12                         sb->buf[pos] = ' ';
13                         for (cnt = 0; isspace(sb->buf[pos + cnt + 1]); cnt++);
14                         strbuf_remove(sb, pos + 1, cnt);
15                 }
16         }
17 }
18
19 static void get_sane_name(struct strbuf *out, struct strbuf *name, struct strbuf *email)
20 {
21         struct strbuf *src = name;
22         if (name->len < 3 || 60 < name->len || strchr(name->buf, '@') ||
23                 strchr(name->buf, '<') || strchr(name->buf, '>'))
24                 src = email;
25         else if (name == out)
26                 return;
27         strbuf_reset(out);
28         strbuf_addbuf(out, src);
29 }
30
31 static void parse_bogus_from(struct mailinfo *mi, const struct strbuf *line)
32 {
33         /* John Doe <johndoe> */
34
35         char *bra, *ket;
36         /* This is fallback, so do not bother if we already have an
37          * e-mail address.
38          */
39         if (mi->email.len)
40                 return;
41
42         bra = strchr(line->buf, '<');
43         if (!bra)
44                 return;
45         ket = strchr(bra, '>');
46         if (!ket)
47                 return;
48
49         strbuf_reset(&mi->email);
50         strbuf_add(&mi->email, bra + 1, ket - bra - 1);
51
52         strbuf_reset(&mi->name);
53         strbuf_add(&mi->name, line->buf, bra - line->buf);
54         strbuf_trim(&mi->name);
55         get_sane_name(&mi->name, &mi->name, &mi->email);
56 }
57
58 static const char *unquote_comment(struct strbuf *outbuf, const char *in)
59 {
60         int c;
61         int take_next_literally = 0;
62
63         strbuf_addch(outbuf, '(');
64
65         while ((c = *in++) != 0) {
66                 if (take_next_literally == 1) {
67                         take_next_literally = 0;
68                 } else {
69                         switch (c) {
70                         case '\\':
71                                 take_next_literally = 1;
72                                 continue;
73                         case '(':
74                                 in = unquote_comment(outbuf, in);
75                                 continue;
76                         case ')':
77                                 strbuf_addch(outbuf, ')');
78                                 return in;
79                         }
80                 }
81
82                 strbuf_addch(outbuf, c);
83         }
84
85         return in;
86 }
87
88 static const char *unquote_quoted_string(struct strbuf *outbuf, const char *in)
89 {
90         int c;
91         int take_next_literally = 0;
92
93         while ((c = *in++) != 0) {
94                 if (take_next_literally == 1) {
95                         take_next_literally = 0;
96                 } else {
97                         switch (c) {
98                         case '\\':
99                                 take_next_literally = 1;
100                                 continue;
101                         case '"':
102                                 return in;
103                         }
104                 }
105
106                 strbuf_addch(outbuf, c);
107         }
108
109         return in;
110 }
111
112 static void unquote_quoted_pair(struct strbuf *line)
113 {
114         struct strbuf outbuf;
115         const char *in = line->buf;
116         int c;
117
118         strbuf_init(&outbuf, line->len);
119
120         while ((c = *in++) != 0) {
121                 switch (c) {
122                 case '"':
123                         in = unquote_quoted_string(&outbuf, in);
124                         continue;
125                 case '(':
126                         in = unquote_comment(&outbuf, in);
127                         continue;
128                 }
129
130                 strbuf_addch(&outbuf, c);
131         }
132
133         strbuf_swap(&outbuf, line);
134         strbuf_release(&outbuf);
135
136 }
137
138 static void handle_from(struct mailinfo *mi, const struct strbuf *from)
139 {
140         char *at;
141         size_t el;
142         struct strbuf f;
143
144         strbuf_init(&f, from->len);
145         strbuf_addbuf(&f, from);
146
147         unquote_quoted_pair(&f);
148
149         at = strchr(f.buf, '@');
150         if (!at) {
151                 parse_bogus_from(mi, from);
152                 goto out;
153         }
154
155         /*
156          * If we already have one email, don't take any confusing lines
157          */
158         if (mi->email.len && strchr(at + 1, '@'))
159                 goto out;
160
161         /* Pick up the string around '@', possibly delimited with <>
162          * pair; that is the email part.
163          */
164         while (at > f.buf) {
165                 char c = at[-1];
166                 if (isspace(c))
167                         break;
168                 if (c == '<') {
169                         at[-1] = ' ';
170                         break;
171                 }
172                 at--;
173         }
174         el = strcspn(at, " \n\t\r\v\f>");
175         strbuf_reset(&mi->email);
176         strbuf_add(&mi->email, at, el);
177         strbuf_remove(&f, at - f.buf, el + (at[el] ? 1 : 0));
178
179         /* The remainder is name.  It could be
180          *
181          * - "John Doe <john.doe@xz>"                   (a), or
182          * - "john.doe@xz (John Doe)"                   (b), or
183          * - "John (zzz) Doe <john.doe@xz> (Comment)"   (c)
184          *
185          * but we have removed the email part, so
186          *
187          * - remove extra spaces which could stay after email (case 'c'), and
188          * - trim from both ends, possibly removing the () pair at the end
189          *   (cases 'a' and 'b').
190          */
191         cleanup_space(&f);
192         strbuf_trim(&f);
193         if (f.buf[0] == '(' && f.len && f.buf[f.len - 1] == ')') {
194                 strbuf_remove(&f, 0, 1);
195                 strbuf_setlen(&f, f.len - 1);
196         }
197
198         get_sane_name(&mi->name, &f, &mi->email);
199 out:
200         strbuf_release(&f);
201 }
202
203 static void handle_header(struct strbuf **out, const struct strbuf *line)
204 {
205         if (!*out) {
206                 *out = xmalloc(sizeof(struct strbuf));
207                 strbuf_init(*out, line->len);
208         } else
209                 strbuf_reset(*out);
210
211         strbuf_addbuf(*out, line);
212 }
213
214 /* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
215  * to have enough heuristics to grok MIME encoded patches often found
216  * on our mailing lists.  For example, we do not even treat header lines
217  * case insensitively.
218  */
219
220 static int slurp_attr(const char *line, const char *name, struct strbuf *attr)
221 {
222         const char *ends, *ap = strcasestr(line, name);
223         size_t sz;
224
225         strbuf_setlen(attr, 0);
226         if (!ap)
227                 return 0;
228         ap += strlen(name);
229         if (*ap == '"') {
230                 ap++;
231                 ends = "\"";
232         }
233         else
234                 ends = "; \t";
235         sz = strcspn(ap, ends);
236         strbuf_add(attr, ap, sz);
237         return 1;
238 }
239
240 static void handle_content_type(struct mailinfo *mi, struct strbuf *line)
241 {
242         struct strbuf *boundary = xmalloc(sizeof(struct strbuf));
243         strbuf_init(boundary, line->len);
244
245         if (slurp_attr(line->buf, "boundary=", boundary)) {
246                 strbuf_insert(boundary, 0, "--", 2);
247                 if (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) {
248                         error("Too many boundaries to handle");
249                         mi->input_error = -1;
250                         mi->content_top = &mi->content[MAX_BOUNDARIES] - 1;
251                         return;
252                 }
253                 *(mi->content_top) = boundary;
254                 boundary = NULL;
255         }
256         slurp_attr(line->buf, "charset=", &mi->charset);
257
258         if (boundary) {
259                 strbuf_release(boundary);
260                 free(boundary);
261         }
262 }
263
264 static void handle_content_transfer_encoding(struct mailinfo *mi,
265                                              const struct strbuf *line)
266 {
267         if (strcasestr(line->buf, "base64"))
268                 mi->transfer_encoding = TE_BASE64;
269         else if (strcasestr(line->buf, "quoted-printable"))
270                 mi->transfer_encoding = TE_QP;
271         else
272                 mi->transfer_encoding = TE_DONTCARE;
273 }
274
275 static int is_multipart_boundary(struct mailinfo *mi, const struct strbuf *line)
276 {
277         struct strbuf *content_top = *(mi->content_top);
278
279         return ((content_top->len <= line->len) &&
280                 !memcmp(line->buf, content_top->buf, content_top->len));
281 }
282
283 static void cleanup_subject(struct mailinfo *mi, struct strbuf *subject)
284 {
285         size_t at = 0;
286
287         while (at < subject->len) {
288                 char *pos;
289                 size_t remove;
290
291                 switch (subject->buf[at]) {
292                 case 'r': case 'R':
293                         if (subject->len <= at + 3)
294                                 break;
295                         if ((subject->buf[at + 1] == 'e' ||
296                              subject->buf[at + 1] == 'E') &&
297                             subject->buf[at + 2] == ':') {
298                                 strbuf_remove(subject, at, 3);
299                                 continue;
300                         }
301                         at++;
302                         break;
303                 case ' ': case '\t': case ':':
304                         strbuf_remove(subject, at, 1);
305                         continue;
306                 case '[':
307                         pos = strchr(subject->buf + at, ']');
308                         if (!pos)
309                                 break;
310                         remove = pos - subject->buf + at + 1;
311                         if (!mi->keep_non_patch_brackets_in_subject ||
312                             (7 <= remove &&
313                              memmem(subject->buf + at, remove, "PATCH", 5)))
314                                 strbuf_remove(subject, at, remove);
315                         else {
316                                 at += remove;
317                                 /*
318                                  * If the input had a space after the ], keep
319                                  * it.  We don't bother with finding the end of
320                                  * the space, since we later normalize it
321                                  * anyway.
322                                  */
323                                 if (isspace(subject->buf[at]))
324                                         at += 1;
325                         }
326                         continue;
327                 }
328                 break;
329         }
330         strbuf_trim(subject);
331 }
332
333 #define MAX_HDR_PARSED 10
334 static const char *header[MAX_HDR_PARSED] = {
335         "From","Subject","Date",
336 };
337
338 static inline int cmp_header(const struct strbuf *line, const char *hdr)
339 {
340         int len = strlen(hdr);
341         return !strncasecmp(line->buf, hdr, len) && line->len > len &&
342                         line->buf[len] == ':' && isspace(line->buf[len + 1]);
343 }
344
345 static int is_format_patch_separator(const char *line, int len)
346 {
347         static const char SAMPLE[] =
348                 "From e6807f3efca28b30decfecb1732a56c7db1137ee Mon Sep 17 00:00:00 2001\n";
349         const char *cp;
350
351         if (len != strlen(SAMPLE))
352                 return 0;
353         if (!skip_prefix(line, "From ", &cp))
354                 return 0;
355         if (strspn(cp, "0123456789abcdef") != 40)
356                 return 0;
357         cp += 40;
358         return !memcmp(SAMPLE + (cp - line), cp, strlen(SAMPLE) - (cp - line));
359 }
360
361 static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
362 {
363         const char *in = q_seg->buf;
364         int c;
365         struct strbuf *out = xmalloc(sizeof(struct strbuf));
366         strbuf_init(out, q_seg->len);
367
368         while ((c = *in++) != 0) {
369                 if (c == '=') {
370                         int ch, d = *in;
371                         if (d == '\n' || !d)
372                                 break; /* drop trailing newline */
373                         ch = hex2chr(in);
374                         if (ch >= 0) {
375                                 strbuf_addch(out, ch);
376                                 in += 2;
377                                 continue;
378                         }
379                         /* garbage -- fall through */
380                 }
381                 if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
382                         c = 0x20;
383                 strbuf_addch(out, c);
384         }
385         return out;
386 }
387
388 static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
389 {
390         /* Decode in..ep, possibly in-place to ot */
391         int c, pos = 0, acc = 0;
392         const char *in = b_seg->buf;
393         struct strbuf *out = xmalloc(sizeof(struct strbuf));
394         strbuf_init(out, b_seg->len);
395
396         while ((c = *in++) != 0) {
397                 if (c == '+')
398                         c = 62;
399                 else if (c == '/')
400                         c = 63;
401                 else if ('A' <= c && c <= 'Z')
402                         c -= 'A';
403                 else if ('a' <= c && c <= 'z')
404                         c -= 'a' - 26;
405                 else if ('0' <= c && c <= '9')
406                         c -= '0' - 52;
407                 else
408                         continue; /* garbage */
409                 switch (pos++) {
410                 case 0:
411                         acc = (c << 2);
412                         break;
413                 case 1:
414                         strbuf_addch(out, (acc | (c >> 4)));
415                         acc = (c & 15) << 4;
416                         break;
417                 case 2:
418                         strbuf_addch(out, (acc | (c >> 2)));
419                         acc = (c & 3) << 6;
420                         break;
421                 case 3:
422                         strbuf_addch(out, (acc | c));
423                         acc = pos = 0;
424                         break;
425                 }
426         }
427         return out;
428 }
429
430 static int convert_to_utf8(struct mailinfo *mi,
431                            struct strbuf *line, const char *charset)
432 {
433         char *out;
434
435         if (!mi->metainfo_charset || !charset || !*charset)
436                 return 0;
437
438         if (same_encoding(mi->metainfo_charset, charset))
439                 return 0;
440         out = reencode_string(line->buf, mi->metainfo_charset, charset);
441         if (!out) {
442                 mi->input_error = -1;
443                 return error("cannot convert from %s to %s",
444                              charset, mi->metainfo_charset);
445         }
446         strbuf_attach(line, out, strlen(out), strlen(out));
447         return 0;
448 }
449
450 static void decode_header(struct mailinfo *mi, struct strbuf *it)
451 {
452         char *in, *ep, *cp;
453         struct strbuf outbuf = STRBUF_INIT, *dec;
454         struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
455         int found_error = 1; /* pessimism */
456
457         in = it->buf;
458         while (in - it->buf <= it->len && (ep = strstr(in, "=?")) != NULL) {
459                 int encoding;
460                 strbuf_reset(&charset_q);
461                 strbuf_reset(&piecebuf);
462
463                 if (in != ep) {
464                         /*
465                          * We are about to process an encoded-word
466                          * that begins at ep, but there is something
467                          * before the encoded word.
468                          */
469                         char *scan;
470                         for (scan = in; scan < ep; scan++)
471                                 if (!isspace(*scan))
472                                         break;
473
474                         if (scan != ep || in == it->buf) {
475                                 /*
476                                  * We should not lose that "something",
477                                  * unless we have just processed an
478                                  * encoded-word, and there is only LWS
479                                  * before the one we are about to process.
480                                  */
481                                 strbuf_add(&outbuf, in, ep - in);
482                         }
483                 }
484                 /* E.g.
485                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
486                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
487                  */
488                 ep += 2;
489
490                 if (ep - it->buf >= it->len || !(cp = strchr(ep, '?')))
491                         goto release_return;
492
493                 if (cp + 3 - it->buf > it->len)
494                         goto release_return;
495                 strbuf_add(&charset_q, ep, cp - ep);
496
497                 encoding = cp[1];
498                 if (!encoding || cp[2] != '?')
499                         goto release_return;
500                 ep = strstr(cp + 3, "?=");
501                 if (!ep)
502                         goto release_return;
503                 strbuf_add(&piecebuf, cp + 3, ep - cp - 3);
504                 switch (tolower(encoding)) {
505                 default:
506                         goto release_return;
507                 case 'b':
508                         dec = decode_b_segment(&piecebuf);
509                         break;
510                 case 'q':
511                         dec = decode_q_segment(&piecebuf, 1);
512                         break;
513                 }
514                 if (convert_to_utf8(mi, dec, charset_q.buf))
515                         goto release_return;
516
517                 strbuf_addbuf(&outbuf, dec);
518                 strbuf_release(dec);
519                 free(dec);
520                 in = ep + 2;
521         }
522         strbuf_addstr(&outbuf, in);
523         strbuf_reset(it);
524         strbuf_addbuf(it, &outbuf);
525         found_error = 0;
526 release_return:
527         strbuf_release(&outbuf);
528         strbuf_release(&charset_q);
529         strbuf_release(&piecebuf);
530
531         if (found_error)
532                 mi->input_error = -1;
533 }
534
535 static int check_header(struct mailinfo *mi,
536                         const struct strbuf *line,
537                         struct strbuf *hdr_data[], int overwrite)
538 {
539         int i, ret = 0, len;
540         struct strbuf sb = STRBUF_INIT;
541
542         /* search for the interesting parts */
543         for (i = 0; header[i]; i++) {
544                 int len = strlen(header[i]);
545                 if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
546                         /* Unwrap inline B and Q encoding, and optionally
547                          * normalize the meta information to utf8.
548                          */
549                         strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
550                         decode_header(mi, &sb);
551                         handle_header(&hdr_data[i], &sb);
552                         ret = 1;
553                         goto check_header_out;
554                 }
555         }
556
557         /* Content stuff */
558         if (cmp_header(line, "Content-Type")) {
559                 len = strlen("Content-Type: ");
560                 strbuf_add(&sb, line->buf + len, line->len - len);
561                 decode_header(mi, &sb);
562                 strbuf_insert(&sb, 0, "Content-Type: ", len);
563                 handle_content_type(mi, &sb);
564                 ret = 1;
565                 goto check_header_out;
566         }
567         if (cmp_header(line, "Content-Transfer-Encoding")) {
568                 len = strlen("Content-Transfer-Encoding: ");
569                 strbuf_add(&sb, line->buf + len, line->len - len);
570                 decode_header(mi, &sb);
571                 handle_content_transfer_encoding(mi, &sb);
572                 ret = 1;
573                 goto check_header_out;
574         }
575         if (cmp_header(line, "Message-Id")) {
576                 len = strlen("Message-Id: ");
577                 strbuf_add(&sb, line->buf + len, line->len - len);
578                 decode_header(mi, &sb);
579                 if (mi->add_message_id)
580                         mi->message_id = strbuf_detach(&sb, NULL);
581                 ret = 1;
582                 goto check_header_out;
583         }
584
585 check_header_out:
586         strbuf_release(&sb);
587         return ret;
588 }
589
590 /*
591  * Returns 1 if the given line or any line beginning with the given line is an
592  * in-body header (that is, check_header will succeed when passed
593  * mi->s_hdr_data).
594  */
595 static int is_inbody_header(const struct mailinfo *mi,
596                             const struct strbuf *line)
597 {
598         int i;
599         for (i = 0; header[i]; i++)
600                 if (!mi->s_hdr_data[i] && cmp_header(line, header[i]))
601                         return 1;
602         return 0;
603 }
604
605 static void decode_transfer_encoding(struct mailinfo *mi, struct strbuf *line)
606 {
607         struct strbuf *ret;
608
609         switch (mi->transfer_encoding) {
610         case TE_QP:
611                 ret = decode_q_segment(line, 0);
612                 break;
613         case TE_BASE64:
614                 ret = decode_b_segment(line);
615                 break;
616         case TE_DONTCARE:
617         default:
618                 return;
619         }
620         strbuf_reset(line);
621         strbuf_addbuf(line, ret);
622         strbuf_release(ret);
623         free(ret);
624 }
625
626 static inline int patchbreak(const struct strbuf *line)
627 {
628         size_t i;
629
630         /* Beginning of a "diff -" header? */
631         if (starts_with(line->buf, "diff -"))
632                 return 1;
633
634         /* CVS "Index: " line? */
635         if (starts_with(line->buf, "Index: "))
636                 return 1;
637
638         /*
639          * "--- <filename>" starts patches without headers
640          * "---<sp>*" is a manual separator
641          */
642         if (line->len < 4)
643                 return 0;
644
645         if (starts_with(line->buf, "---")) {
646                 /* space followed by a filename? */
647                 if (line->buf[3] == ' ' && !isspace(line->buf[4]))
648                         return 1;
649                 /* Just whitespace? */
650                 for (i = 3; i < line->len; i++) {
651                         unsigned char c = line->buf[i];
652                         if (c == '\n')
653                                 return 1;
654                         if (!isspace(c))
655                                 break;
656                 }
657                 return 0;
658         }
659         return 0;
660 }
661
662 static int is_scissors_line(const char *line)
663 {
664         const char *c;
665         int scissors = 0, gap = 0;
666         const char *first_nonblank = NULL, *last_nonblank = NULL;
667         int visible, perforation = 0, in_perforation = 0;
668
669         for (c = line; *c; c++) {
670                 if (isspace(*c)) {
671                         if (in_perforation) {
672                                 perforation++;
673                                 gap++;
674                         }
675                         continue;
676                 }
677                 last_nonblank = c;
678                 if (first_nonblank == NULL)
679                         first_nonblank = c;
680                 if (*c == '-') {
681                         in_perforation = 1;
682                         perforation++;
683                         continue;
684                 }
685                 if ((!memcmp(c, ">8", 2) || !memcmp(c, "8<", 2) ||
686                      !memcmp(c, ">%", 2) || !memcmp(c, "%<", 2))) {
687                         in_perforation = 1;
688                         perforation += 2;
689                         scissors += 2;
690                         c++;
691                         continue;
692                 }
693                 in_perforation = 0;
694         }
695
696         /*
697          * The mark must be at least 8 bytes long (e.g. "-- >8 --").
698          * Even though there can be arbitrary cruft on the same line
699          * (e.g. "cut here"), in order to avoid misidentification, the
700          * perforation must occupy more than a third of the visible
701          * width of the line, and dashes and scissors must occupy more
702          * than half of the perforation.
703          */
704
705         if (first_nonblank && last_nonblank)
706                 visible = last_nonblank - first_nonblank + 1;
707         else
708                 visible = 0;
709         return (scissors && 8 <= visible &&
710                 visible < perforation * 3 &&
711                 gap * 2 < perforation);
712 }
713
714 static void flush_inbody_header_accum(struct mailinfo *mi)
715 {
716         if (!mi->inbody_header_accum.len)
717                 return;
718         if (!check_header(mi, &mi->inbody_header_accum, mi->s_hdr_data, 0))
719                 die("BUG: inbody_header_accum, if not empty, must always contain a valid in-body header");
720         strbuf_reset(&mi->inbody_header_accum);
721 }
722
723 static int check_inbody_header(struct mailinfo *mi, const struct strbuf *line)
724 {
725         if (mi->inbody_header_accum.len &&
726             (line->buf[0] == ' ' || line->buf[0] == '\t')) {
727                 if (mi->use_scissors && is_scissors_line(line->buf)) {
728                         /*
729                          * This is a scissors line; do not consider this line
730                          * as a header continuation line.
731                          */
732                         flush_inbody_header_accum(mi);
733                         return 0;
734                 }
735                 strbuf_strip_suffix(&mi->inbody_header_accum, "\n");
736                 strbuf_addbuf(&mi->inbody_header_accum, line);
737                 return 1;
738         }
739
740         flush_inbody_header_accum(mi);
741
742         if (starts_with(line->buf, ">From") && isspace(line->buf[5]))
743                 return is_format_patch_separator(line->buf + 1, line->len - 1);
744         if (starts_with(line->buf, "[PATCH]") && isspace(line->buf[7])) {
745                 int i;
746                 for (i = 0; header[i]; i++)
747                         if (!strcmp("Subject", header[i])) {
748                                 handle_header(&mi->s_hdr_data[i], line);
749                                 return 1;
750                         }
751                 return 0;
752         }
753         if (is_inbody_header(mi, line)) {
754                 strbuf_addbuf(&mi->inbody_header_accum, line);
755                 return 1;
756         }
757         return 0;
758 }
759
760 static int handle_commit_msg(struct mailinfo *mi, struct strbuf *line)
761 {
762         assert(!mi->filter_stage);
763
764         if (mi->header_stage) {
765                 if (!line->len || (line->len == 1 && line->buf[0] == '\n')) {
766                         if (mi->inbody_header_accum.len) {
767                                 flush_inbody_header_accum(mi);
768                                 mi->header_stage = 0;
769                         }
770                         return 0;
771                 }
772         }
773
774         if (mi->use_inbody_headers && mi->header_stage) {
775                 mi->header_stage = check_inbody_header(mi, line);
776                 if (mi->header_stage)
777                         return 0;
778         } else
779                 /* Only trim the first (blank) line of the commit message
780                  * when ignoring in-body headers.
781                  */
782                 mi->header_stage = 0;
783
784         /* normalize the log message to UTF-8. */
785         if (convert_to_utf8(mi, line, mi->charset.buf))
786                 return 0; /* mi->input_error already set */
787
788         if (mi->use_scissors && is_scissors_line(line->buf)) {
789                 int i;
790
791                 strbuf_setlen(&mi->log_message, 0);
792                 mi->header_stage = 1;
793
794                 /*
795                  * We may have already read "secondary headers"; purge
796                  * them to give ourselves a clean restart.
797                  */
798                 for (i = 0; header[i]; i++) {
799                         if (mi->s_hdr_data[i])
800                                 strbuf_release(mi->s_hdr_data[i]);
801                         mi->s_hdr_data[i] = NULL;
802                 }
803                 return 0;
804         }
805
806         if (patchbreak(line)) {
807                 if (mi->message_id)
808                         strbuf_addf(&mi->log_message,
809                                     "Message-Id: %s\n", mi->message_id);
810                 return 1;
811         }
812
813         strbuf_addbuf(&mi->log_message, line);
814         return 0;
815 }
816
817 static void handle_patch(struct mailinfo *mi, const struct strbuf *line)
818 {
819         fwrite(line->buf, 1, line->len, mi->patchfile);
820         mi->patch_lines++;
821 }
822
823 static void handle_filter(struct mailinfo *mi, struct strbuf *line)
824 {
825         switch (mi->filter_stage) {
826         case 0:
827                 if (!handle_commit_msg(mi, line))
828                         break;
829                 mi->filter_stage++;
830                 /* fallthrough */
831         case 1:
832                 handle_patch(mi, line);
833                 break;
834         }
835 }
836
837 static int is_rfc2822_header(const struct strbuf *line)
838 {
839         /*
840          * The section that defines the loosest possible
841          * field name is "3.6.8 Optional fields".
842          *
843          * optional-field = field-name ":" unstructured CRLF
844          * field-name = 1*ftext
845          * ftext = %d33-57 / %59-126
846          */
847         int ch;
848         char *cp = line->buf;
849
850         /* Count mbox From headers as headers */
851         if (starts_with(cp, "From ") || starts_with(cp, ">From "))
852                 return 1;
853
854         while ((ch = *cp++)) {
855                 if (ch == ':')
856                         return 1;
857                 if ((33 <= ch && ch <= 57) ||
858                     (59 <= ch && ch <= 126))
859                         continue;
860                 break;
861         }
862         return 0;
863 }
864
865 static int read_one_header_line(struct strbuf *line, FILE *in)
866 {
867         struct strbuf continuation = STRBUF_INIT;
868
869         /* Get the first part of the line. */
870         if (strbuf_getline_lf(line, in))
871                 return 0;
872
873         /*
874          * Is it an empty line or not a valid rfc2822 header?
875          * If so, stop here, and return false ("not a header")
876          */
877         strbuf_rtrim(line);
878         if (!line->len || !is_rfc2822_header(line)) {
879                 /* Re-add the newline */
880                 strbuf_addch(line, '\n');
881                 return 0;
882         }
883
884         /*
885          * Now we need to eat all the continuation lines..
886          * Yuck, 2822 header "folding"
887          */
888         for (;;) {
889                 int peek;
890
891                 peek = fgetc(in);
892                 if (peek == EOF)
893                         break;
894                 ungetc(peek, in);
895                 if (peek != ' ' && peek != '\t')
896                         break;
897                 if (strbuf_getline_lf(&continuation, in))
898                         break;
899                 continuation.buf[0] = ' ';
900                 strbuf_rtrim(&continuation);
901                 strbuf_addbuf(line, &continuation);
902         }
903         strbuf_release(&continuation);
904
905         return 1;
906 }
907
908 static int find_boundary(struct mailinfo *mi, struct strbuf *line)
909 {
910         while (!strbuf_getline_lf(line, mi->input)) {
911                 if (*(mi->content_top) && is_multipart_boundary(mi, line))
912                         return 1;
913         }
914         return 0;
915 }
916
917 static int handle_boundary(struct mailinfo *mi, struct strbuf *line)
918 {
919         struct strbuf newline = STRBUF_INIT;
920
921         strbuf_addch(&newline, '\n');
922 again:
923         if (line->len >= (*(mi->content_top))->len + 2 &&
924             !memcmp(line->buf + (*(mi->content_top))->len, "--", 2)) {
925                 /* we hit an end boundary */
926                 /* pop the current boundary off the stack */
927                 strbuf_release(*(mi->content_top));
928                 FREE_AND_NULL(*(mi->content_top));
929
930                 /* technically won't happen as is_multipart_boundary()
931                    will fail first.  But just in case..
932                  */
933                 if (--mi->content_top < mi->content) {
934                         error("Detected mismatched boundaries, can't recover");
935                         mi->input_error = -1;
936                         mi->content_top = mi->content;
937                         strbuf_release(&newline);
938                         return 0;
939                 }
940                 handle_filter(mi, &newline);
941                 strbuf_release(&newline);
942                 if (mi->input_error)
943                         return 0;
944
945                 /* skip to the next boundary */
946                 if (!find_boundary(mi, line))
947                         return 0;
948                 goto again;
949         }
950
951         /* set some defaults */
952         mi->transfer_encoding = TE_DONTCARE;
953         strbuf_reset(&mi->charset);
954
955         /* slurp in this section's info */
956         while (read_one_header_line(line, mi->input))
957                 check_header(mi, line, mi->p_hdr_data, 0);
958
959         strbuf_release(&newline);
960         /* replenish line */
961         if (strbuf_getline_lf(line, mi->input))
962                 return 0;
963         strbuf_addch(line, '\n');
964         return 1;
965 }
966
967 static void handle_body(struct mailinfo *mi, struct strbuf *line)
968 {
969         struct strbuf prev = STRBUF_INIT;
970
971         /* Skip up to the first boundary */
972         if (*(mi->content_top)) {
973                 if (!find_boundary(mi, line))
974                         goto handle_body_out;
975         }
976
977         do {
978                 /* process any boundary lines */
979                 if (*(mi->content_top) && is_multipart_boundary(mi, line)) {
980                         /* flush any leftover */
981                         if (prev.len) {
982                                 handle_filter(mi, &prev);
983                                 strbuf_reset(&prev);
984                         }
985                         if (!handle_boundary(mi, line))
986                                 goto handle_body_out;
987                 }
988
989                 /* Unwrap transfer encoding */
990                 decode_transfer_encoding(mi, line);
991
992                 switch (mi->transfer_encoding) {
993                 case TE_BASE64:
994                 case TE_QP:
995                 {
996                         struct strbuf **lines, **it, *sb;
997
998                         /* Prepend any previous partial lines */
999                         strbuf_insert(line, 0, prev.buf, prev.len);
1000                         strbuf_reset(&prev);
1001
1002                         /*
1003                          * This is a decoded line that may contain
1004                          * multiple new lines.  Pass only one chunk
1005                          * at a time to handle_filter()
1006                          */
1007                         lines = strbuf_split(line, '\n');
1008                         for (it = lines; (sb = *it); it++) {
1009                                 if (*(it + 1) == NULL) /* The last line */
1010                                         if (sb->buf[sb->len - 1] != '\n') {
1011                                                 /* Partial line, save it for later. */
1012                                                 strbuf_addbuf(&prev, sb);
1013                                                 break;
1014                                         }
1015                                 handle_filter(mi, sb);
1016                         }
1017                         /*
1018                          * The partial chunk is saved in "prev" and will be
1019                          * appended by the next iteration of read_line_with_nul().
1020                          */
1021                         strbuf_list_free(lines);
1022                         break;
1023                 }
1024                 default:
1025                         handle_filter(mi, line);
1026                 }
1027
1028                 if (mi->input_error)
1029                         break;
1030         } while (!strbuf_getwholeline(line, mi->input, '\n'));
1031
1032         flush_inbody_header_accum(mi);
1033
1034 handle_body_out:
1035         strbuf_release(&prev);
1036 }
1037
1038 static void output_header_lines(FILE *fout, const char *hdr, const struct strbuf *data)
1039 {
1040         const char *sp = data->buf;
1041         while (1) {
1042                 char *ep = strchr(sp, '\n');
1043                 int len;
1044                 if (!ep)
1045                         len = strlen(sp);
1046                 else
1047                         len = ep - sp;
1048                 fprintf(fout, "%s: %.*s\n", hdr, len, sp);
1049                 if (!ep)
1050                         break;
1051                 sp = ep + 1;
1052         }
1053 }
1054
1055 static void handle_info(struct mailinfo *mi)
1056 {
1057         struct strbuf *hdr;
1058         int i;
1059
1060         for (i = 0; header[i]; i++) {
1061                 /* only print inbody headers if we output a patch file */
1062                 if (mi->patch_lines && mi->s_hdr_data[i])
1063                         hdr = mi->s_hdr_data[i];
1064                 else if (mi->p_hdr_data[i])
1065                         hdr = mi->p_hdr_data[i];
1066                 else
1067                         continue;
1068
1069                 if (!strcmp(header[i], "Subject")) {
1070                         if (!mi->keep_subject) {
1071                                 cleanup_subject(mi, hdr);
1072                                 cleanup_space(hdr);
1073                         }
1074                         output_header_lines(mi->output, "Subject", hdr);
1075                 } else if (!strcmp(header[i], "From")) {
1076                         cleanup_space(hdr);
1077                         handle_from(mi, hdr);
1078                         fprintf(mi->output, "Author: %s\n", mi->name.buf);
1079                         fprintf(mi->output, "Email: %s\n", mi->email.buf);
1080                 } else {
1081                         cleanup_space(hdr);
1082                         fprintf(mi->output, "%s: %s\n", header[i], hdr->buf);
1083                 }
1084         }
1085         fprintf(mi->output, "\n");
1086 }
1087
1088 int mailinfo(struct mailinfo *mi, const char *msg, const char *patch)
1089 {
1090         FILE *cmitmsg;
1091         int peek;
1092         struct strbuf line = STRBUF_INIT;
1093
1094         cmitmsg = fopen(msg, "w");
1095         if (!cmitmsg) {
1096                 perror(msg);
1097                 return -1;
1098         }
1099         mi->patchfile = fopen(patch, "w");
1100         if (!mi->patchfile) {
1101                 perror(patch);
1102                 fclose(cmitmsg);
1103                 return -1;
1104         }
1105
1106         mi->p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*(mi->p_hdr_data)));
1107         mi->s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*(mi->s_hdr_data)));
1108
1109         do {
1110                 peek = fgetc(mi->input);
1111                 if (peek == EOF) {
1112                         fclose(cmitmsg);
1113                         return error("empty patch: '%s'", patch);
1114                 }
1115         } while (isspace(peek));
1116         ungetc(peek, mi->input);
1117
1118         /* process the email header */
1119         while (read_one_header_line(&line, mi->input))
1120                 check_header(mi, &line, mi->p_hdr_data, 1);
1121
1122         handle_body(mi, &line);
1123         fwrite(mi->log_message.buf, 1, mi->log_message.len, cmitmsg);
1124         fclose(cmitmsg);
1125         fclose(mi->patchfile);
1126
1127         handle_info(mi);
1128         strbuf_release(&line);
1129         return mi->input_error;
1130 }
1131
1132 static int git_mailinfo_config(const char *var, const char *value, void *mi_)
1133 {
1134         struct mailinfo *mi = mi_;
1135
1136         if (!starts_with(var, "mailinfo."))
1137                 return git_default_config(var, value, NULL);
1138         if (!strcmp(var, "mailinfo.scissors")) {
1139                 mi->use_scissors = git_config_bool(var, value);
1140                 return 0;
1141         }
1142         /* perhaps others here */
1143         return 0;
1144 }
1145
1146 void setup_mailinfo(struct mailinfo *mi)
1147 {
1148         memset(mi, 0, sizeof(*mi));
1149         strbuf_init(&mi->name, 0);
1150         strbuf_init(&mi->email, 0);
1151         strbuf_init(&mi->charset, 0);
1152         strbuf_init(&mi->log_message, 0);
1153         strbuf_init(&mi->inbody_header_accum, 0);
1154         mi->header_stage = 1;
1155         mi->use_inbody_headers = 1;
1156         mi->content_top = mi->content;
1157         git_config(git_mailinfo_config, mi);
1158 }
1159
1160 void clear_mailinfo(struct mailinfo *mi)
1161 {
1162         int i;
1163
1164         strbuf_release(&mi->name);
1165         strbuf_release(&mi->email);
1166         strbuf_release(&mi->charset);
1167         strbuf_release(&mi->inbody_header_accum);
1168         free(mi->message_id);
1169
1170         if (mi->p_hdr_data)
1171                 for (i = 0; mi->p_hdr_data[i]; i++)
1172                         strbuf_release(mi->p_hdr_data[i]);
1173         free(mi->p_hdr_data);
1174         if (mi->s_hdr_data)
1175                 for (i = 0; mi->s_hdr_data[i]; i++)
1176                         strbuf_release(mi->s_hdr_data[i]);
1177         free(mi->s_hdr_data);
1178
1179         while (mi->content < mi->content_top) {
1180                 free(*(mi->content_top));
1181                 mi->content_top--;
1182         }
1183
1184         strbuf_release(&mi->log_message);
1185 }