builtin/am: make hash size independent
[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 int has_attr_value(const char *line, const char *name, const char *value)
241 {
242         struct strbuf sb = STRBUF_INIT;
243         int rc = slurp_attr(line, name, &sb) && !strcasecmp(sb.buf, value);
244         strbuf_release(&sb);
245         return rc;
246 }
247
248 static void handle_content_type(struct mailinfo *mi, struct strbuf *line)
249 {
250         struct strbuf *boundary = xmalloc(sizeof(struct strbuf));
251         strbuf_init(boundary, line->len);
252
253         mi->format_flowed = has_attr_value(line->buf, "format=", "flowed");
254         mi->delsp = has_attr_value(line->buf, "delsp=", "yes");
255
256         if (slurp_attr(line->buf, "boundary=", boundary)) {
257                 strbuf_insert(boundary, 0, "--", 2);
258                 if (++mi->content_top >= &mi->content[MAX_BOUNDARIES]) {
259                         error("Too many boundaries to handle");
260                         mi->input_error = -1;
261                         mi->content_top = &mi->content[MAX_BOUNDARIES] - 1;
262                         return;
263                 }
264                 *(mi->content_top) = boundary;
265                 boundary = NULL;
266         }
267         slurp_attr(line->buf, "charset=", &mi->charset);
268
269         if (boundary) {
270                 strbuf_release(boundary);
271                 free(boundary);
272         }
273 }
274
275 static void handle_content_transfer_encoding(struct mailinfo *mi,
276                                              const struct strbuf *line)
277 {
278         if (strcasestr(line->buf, "base64"))
279                 mi->transfer_encoding = TE_BASE64;
280         else if (strcasestr(line->buf, "quoted-printable"))
281                 mi->transfer_encoding = TE_QP;
282         else
283                 mi->transfer_encoding = TE_DONTCARE;
284 }
285
286 static int is_multipart_boundary(struct mailinfo *mi, const struct strbuf *line)
287 {
288         struct strbuf *content_top = *(mi->content_top);
289
290         return ((content_top->len <= line->len) &&
291                 !memcmp(line->buf, content_top->buf, content_top->len));
292 }
293
294 static void cleanup_subject(struct mailinfo *mi, struct strbuf *subject)
295 {
296         size_t at = 0;
297
298         while (at < subject->len) {
299                 char *pos;
300                 size_t remove;
301
302                 switch (subject->buf[at]) {
303                 case 'r': case 'R':
304                         if (subject->len <= at + 3)
305                                 break;
306                         if ((subject->buf[at + 1] == 'e' ||
307                              subject->buf[at + 1] == 'E') &&
308                             subject->buf[at + 2] == ':') {
309                                 strbuf_remove(subject, at, 3);
310                                 continue;
311                         }
312                         at++;
313                         break;
314                 case ' ': case '\t': case ':':
315                         strbuf_remove(subject, at, 1);
316                         continue;
317                 case '[':
318                         pos = strchr(subject->buf + at, ']');
319                         if (!pos)
320                                 break;
321                         remove = pos - subject->buf + at + 1;
322                         if (!mi->keep_non_patch_brackets_in_subject ||
323                             (7 <= remove &&
324                              memmem(subject->buf + at, remove, "PATCH", 5)))
325                                 strbuf_remove(subject, at, remove);
326                         else {
327                                 at += remove;
328                                 /*
329                                  * If the input had a space after the ], keep
330                                  * it.  We don't bother with finding the end of
331                                  * the space, since we later normalize it
332                                  * anyway.
333                                  */
334                                 if (isspace(subject->buf[at]))
335                                         at += 1;
336                         }
337                         continue;
338                 }
339                 break;
340         }
341         strbuf_trim(subject);
342 }
343
344 #define MAX_HDR_PARSED 10
345 static const char *header[MAX_HDR_PARSED] = {
346         "From","Subject","Date",
347 };
348
349 static inline int cmp_header(const struct strbuf *line, const char *hdr)
350 {
351         int len = strlen(hdr);
352         return !strncasecmp(line->buf, hdr, len) && line->len > len &&
353                         line->buf[len] == ':' && isspace(line->buf[len + 1]);
354 }
355
356 static int is_format_patch_separator(const char *line, int len)
357 {
358         static const char SAMPLE[] =
359                 "From e6807f3efca28b30decfecb1732a56c7db1137ee Mon Sep 17 00:00:00 2001\n";
360         const char *cp;
361
362         if (len != strlen(SAMPLE))
363                 return 0;
364         if (!skip_prefix(line, "From ", &cp))
365                 return 0;
366         if (strspn(cp, "0123456789abcdef") != 40)
367                 return 0;
368         cp += 40;
369         return !memcmp(SAMPLE + (cp - line), cp, strlen(SAMPLE) - (cp - line));
370 }
371
372 static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
373 {
374         const char *in = q_seg->buf;
375         int c;
376         struct strbuf *out = xmalloc(sizeof(struct strbuf));
377         strbuf_init(out, q_seg->len);
378
379         while ((c = *in++) != 0) {
380                 if (c == '=') {
381                         int ch, d = *in;
382                         if (d == '\n' || !d)
383                                 break; /* drop trailing newline */
384                         ch = hex2chr(in);
385                         if (ch >= 0) {
386                                 strbuf_addch(out, ch);
387                                 in += 2;
388                                 continue;
389                         }
390                         /* garbage -- fall through */
391                 }
392                 if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
393                         c = 0x20;
394                 strbuf_addch(out, c);
395         }
396         return out;
397 }
398
399 static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
400 {
401         /* Decode in..ep, possibly in-place to ot */
402         int c, pos = 0, acc = 0;
403         const char *in = b_seg->buf;
404         struct strbuf *out = xmalloc(sizeof(struct strbuf));
405         strbuf_init(out, b_seg->len);
406
407         while ((c = *in++) != 0) {
408                 if (c == '+')
409                         c = 62;
410                 else if (c == '/')
411                         c = 63;
412                 else if ('A' <= c && c <= 'Z')
413                         c -= 'A';
414                 else if ('a' <= c && c <= 'z')
415                         c -= 'a' - 26;
416                 else if ('0' <= c && c <= '9')
417                         c -= '0' - 52;
418                 else
419                         continue; /* garbage */
420                 switch (pos++) {
421                 case 0:
422                         acc = (c << 2);
423                         break;
424                 case 1:
425                         strbuf_addch(out, (acc | (c >> 4)));
426                         acc = (c & 15) << 4;
427                         break;
428                 case 2:
429                         strbuf_addch(out, (acc | (c >> 2)));
430                         acc = (c & 3) << 6;
431                         break;
432                 case 3:
433                         strbuf_addch(out, (acc | c));
434                         acc = pos = 0;
435                         break;
436                 }
437         }
438         return out;
439 }
440
441 static int convert_to_utf8(struct mailinfo *mi,
442                            struct strbuf *line, const char *charset)
443 {
444         char *out;
445
446         if (!mi->metainfo_charset || !charset || !*charset)
447                 return 0;
448
449         if (same_encoding(mi->metainfo_charset, charset))
450                 return 0;
451         out = reencode_string(line->buf, mi->metainfo_charset, charset);
452         if (!out) {
453                 mi->input_error = -1;
454                 return error("cannot convert from %s to %s",
455                              charset, mi->metainfo_charset);
456         }
457         strbuf_attach(line, out, strlen(out), strlen(out));
458         return 0;
459 }
460
461 static void decode_header(struct mailinfo *mi, struct strbuf *it)
462 {
463         char *in, *ep, *cp;
464         struct strbuf outbuf = STRBUF_INIT, *dec;
465         struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
466         int found_error = 1; /* pessimism */
467
468         in = it->buf;
469         while (in - it->buf <= it->len && (ep = strstr(in, "=?")) != NULL) {
470                 int encoding;
471                 strbuf_reset(&charset_q);
472                 strbuf_reset(&piecebuf);
473
474                 if (in != ep) {
475                         /*
476                          * We are about to process an encoded-word
477                          * that begins at ep, but there is something
478                          * before the encoded word.
479                          */
480                         char *scan;
481                         for (scan = in; scan < ep; scan++)
482                                 if (!isspace(*scan))
483                                         break;
484
485                         if (scan != ep || in == it->buf) {
486                                 /*
487                                  * We should not lose that "something",
488                                  * unless we have just processed an
489                                  * encoded-word, and there is only LWS
490                                  * before the one we are about to process.
491                                  */
492                                 strbuf_add(&outbuf, in, ep - in);
493                         }
494                 }
495                 /* E.g.
496                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
497                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
498                  */
499                 ep += 2;
500
501                 if (ep - it->buf >= it->len || !(cp = strchr(ep, '?')))
502                         goto release_return;
503
504                 if (cp + 3 - it->buf > it->len)
505                         goto release_return;
506                 strbuf_add(&charset_q, ep, cp - ep);
507
508                 encoding = cp[1];
509                 if (!encoding || cp[2] != '?')
510                         goto release_return;
511                 ep = strstr(cp + 3, "?=");
512                 if (!ep)
513                         goto release_return;
514                 strbuf_add(&piecebuf, cp + 3, ep - cp - 3);
515                 switch (tolower(encoding)) {
516                 default:
517                         goto release_return;
518                 case 'b':
519                         dec = decode_b_segment(&piecebuf);
520                         break;
521                 case 'q':
522                         dec = decode_q_segment(&piecebuf, 1);
523                         break;
524                 }
525                 if (convert_to_utf8(mi, dec, charset_q.buf))
526                         goto release_return;
527
528                 strbuf_addbuf(&outbuf, dec);
529                 strbuf_release(dec);
530                 free(dec);
531                 in = ep + 2;
532         }
533         strbuf_addstr(&outbuf, in);
534         strbuf_reset(it);
535         strbuf_addbuf(it, &outbuf);
536         found_error = 0;
537 release_return:
538         strbuf_release(&outbuf);
539         strbuf_release(&charset_q);
540         strbuf_release(&piecebuf);
541
542         if (found_error)
543                 mi->input_error = -1;
544 }
545
546 static int check_header(struct mailinfo *mi,
547                         const struct strbuf *line,
548                         struct strbuf *hdr_data[], int overwrite)
549 {
550         int i, ret = 0, len;
551         struct strbuf sb = STRBUF_INIT;
552
553         /* search for the interesting parts */
554         for (i = 0; header[i]; i++) {
555                 int len = strlen(header[i]);
556                 if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
557                         /* Unwrap inline B and Q encoding, and optionally
558                          * normalize the meta information to utf8.
559                          */
560                         strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
561                         decode_header(mi, &sb);
562                         handle_header(&hdr_data[i], &sb);
563                         ret = 1;
564                         goto check_header_out;
565                 }
566         }
567
568         /* Content stuff */
569         if (cmp_header(line, "Content-Type")) {
570                 len = strlen("Content-Type: ");
571                 strbuf_add(&sb, line->buf + len, line->len - len);
572                 decode_header(mi, &sb);
573                 strbuf_insert(&sb, 0, "Content-Type: ", len);
574                 handle_content_type(mi, &sb);
575                 ret = 1;
576                 goto check_header_out;
577         }
578         if (cmp_header(line, "Content-Transfer-Encoding")) {
579                 len = strlen("Content-Transfer-Encoding: ");
580                 strbuf_add(&sb, line->buf + len, line->len - len);
581                 decode_header(mi, &sb);
582                 handle_content_transfer_encoding(mi, &sb);
583                 ret = 1;
584                 goto check_header_out;
585         }
586         if (cmp_header(line, "Message-Id")) {
587                 len = strlen("Message-Id: ");
588                 strbuf_add(&sb, line->buf + len, line->len - len);
589                 decode_header(mi, &sb);
590                 if (mi->add_message_id)
591                         mi->message_id = strbuf_detach(&sb, NULL);
592                 ret = 1;
593                 goto check_header_out;
594         }
595
596 check_header_out:
597         strbuf_release(&sb);
598         return ret;
599 }
600
601 /*
602  * Returns 1 if the given line or any line beginning with the given line is an
603  * in-body header (that is, check_header will succeed when passed
604  * mi->s_hdr_data).
605  */
606 static int is_inbody_header(const struct mailinfo *mi,
607                             const struct strbuf *line)
608 {
609         int i;
610         for (i = 0; header[i]; i++)
611                 if (!mi->s_hdr_data[i] && cmp_header(line, header[i]))
612                         return 1;
613         return 0;
614 }
615
616 static void decode_transfer_encoding(struct mailinfo *mi, struct strbuf *line)
617 {
618         struct strbuf *ret;
619
620         switch (mi->transfer_encoding) {
621         case TE_QP:
622                 ret = decode_q_segment(line, 0);
623                 break;
624         case TE_BASE64:
625                 ret = decode_b_segment(line);
626                 break;
627         case TE_DONTCARE:
628         default:
629                 return;
630         }
631         strbuf_reset(line);
632         strbuf_addbuf(line, ret);
633         strbuf_release(ret);
634         free(ret);
635 }
636
637 static inline int patchbreak(const struct strbuf *line)
638 {
639         size_t i;
640
641         /* Beginning of a "diff -" header? */
642         if (starts_with(line->buf, "diff -"))
643                 return 1;
644
645         /* CVS "Index: " line? */
646         if (starts_with(line->buf, "Index: "))
647                 return 1;
648
649         /*
650          * "--- <filename>" starts patches without headers
651          * "---<sp>*" is a manual separator
652          */
653         if (line->len < 4)
654                 return 0;
655
656         if (starts_with(line->buf, "---")) {
657                 /* space followed by a filename? */
658                 if (line->buf[3] == ' ' && !isspace(line->buf[4]))
659                         return 1;
660                 /* Just whitespace? */
661                 for (i = 3; i < line->len; i++) {
662                         unsigned char c = line->buf[i];
663                         if (c == '\n')
664                                 return 1;
665                         if (!isspace(c))
666                                 break;
667                 }
668                 return 0;
669         }
670         return 0;
671 }
672
673 static int is_scissors_line(const char *line)
674 {
675         const char *c;
676         int scissors = 0, gap = 0;
677         const char *first_nonblank = NULL, *last_nonblank = NULL;
678         int visible, perforation = 0, in_perforation = 0;
679
680         for (c = line; *c; c++) {
681                 if (isspace(*c)) {
682                         if (in_perforation) {
683                                 perforation++;
684                                 gap++;
685                         }
686                         continue;
687                 }
688                 last_nonblank = c;
689                 if (first_nonblank == NULL)
690                         first_nonblank = c;
691                 if (*c == '-') {
692                         in_perforation = 1;
693                         perforation++;
694                         continue;
695                 }
696                 if ((!memcmp(c, ">8", 2) || !memcmp(c, "8<", 2) ||
697                      !memcmp(c, ">%", 2) || !memcmp(c, "%<", 2))) {
698                         in_perforation = 1;
699                         perforation += 2;
700                         scissors += 2;
701                         c++;
702                         continue;
703                 }
704                 in_perforation = 0;
705         }
706
707         /*
708          * The mark must be at least 8 bytes long (e.g. "-- >8 --").
709          * Even though there can be arbitrary cruft on the same line
710          * (e.g. "cut here"), in order to avoid misidentification, the
711          * perforation must occupy more than a third of the visible
712          * width of the line, and dashes and scissors must occupy more
713          * than half of the perforation.
714          */
715
716         if (first_nonblank && last_nonblank)
717                 visible = last_nonblank - first_nonblank + 1;
718         else
719                 visible = 0;
720         return (scissors && 8 <= visible &&
721                 visible < perforation * 3 &&
722                 gap * 2 < perforation);
723 }
724
725 static void flush_inbody_header_accum(struct mailinfo *mi)
726 {
727         if (!mi->inbody_header_accum.len)
728                 return;
729         if (!check_header(mi, &mi->inbody_header_accum, mi->s_hdr_data, 0))
730                 BUG("inbody_header_accum, if not empty, must always contain a valid in-body header");
731         strbuf_reset(&mi->inbody_header_accum);
732 }
733
734 static int check_inbody_header(struct mailinfo *mi, const struct strbuf *line)
735 {
736         if (mi->inbody_header_accum.len &&
737             (line->buf[0] == ' ' || line->buf[0] == '\t')) {
738                 if (mi->use_scissors && is_scissors_line(line->buf)) {
739                         /*
740                          * This is a scissors line; do not consider this line
741                          * as a header continuation line.
742                          */
743                         flush_inbody_header_accum(mi);
744                         return 0;
745                 }
746                 strbuf_strip_suffix(&mi->inbody_header_accum, "\n");
747                 strbuf_addbuf(&mi->inbody_header_accum, line);
748                 return 1;
749         }
750
751         flush_inbody_header_accum(mi);
752
753         if (starts_with(line->buf, ">From") && isspace(line->buf[5]))
754                 return is_format_patch_separator(line->buf + 1, line->len - 1);
755         if (starts_with(line->buf, "[PATCH]") && isspace(line->buf[7])) {
756                 int i;
757                 for (i = 0; header[i]; i++)
758                         if (!strcmp("Subject", header[i])) {
759                                 handle_header(&mi->s_hdr_data[i], line);
760                                 return 1;
761                         }
762                 return 0;
763         }
764         if (is_inbody_header(mi, line)) {
765                 strbuf_addbuf(&mi->inbody_header_accum, line);
766                 return 1;
767         }
768         return 0;
769 }
770
771 static int handle_commit_msg(struct mailinfo *mi, struct strbuf *line)
772 {
773         assert(!mi->filter_stage);
774
775         if (mi->header_stage) {
776                 if (!line->len || (line->len == 1 && line->buf[0] == '\n')) {
777                         if (mi->inbody_header_accum.len) {
778                                 flush_inbody_header_accum(mi);
779                                 mi->header_stage = 0;
780                         }
781                         return 0;
782                 }
783         }
784
785         if (mi->use_inbody_headers && mi->header_stage) {
786                 mi->header_stage = check_inbody_header(mi, line);
787                 if (mi->header_stage)
788                         return 0;
789         } else
790                 /* Only trim the first (blank) line of the commit message
791                  * when ignoring in-body headers.
792                  */
793                 mi->header_stage = 0;
794
795         /* normalize the log message to UTF-8. */
796         if (convert_to_utf8(mi, line, mi->charset.buf))
797                 return 0; /* mi->input_error already set */
798
799         if (mi->use_scissors && is_scissors_line(line->buf)) {
800                 int i;
801
802                 strbuf_setlen(&mi->log_message, 0);
803                 mi->header_stage = 1;
804
805                 /*
806                  * We may have already read "secondary headers"; purge
807                  * them to give ourselves a clean restart.
808                  */
809                 for (i = 0; header[i]; i++) {
810                         if (mi->s_hdr_data[i])
811                                 strbuf_release(mi->s_hdr_data[i]);
812                         mi->s_hdr_data[i] = NULL;
813                 }
814                 return 0;
815         }
816
817         if (patchbreak(line)) {
818                 if (mi->message_id)
819                         strbuf_addf(&mi->log_message,
820                                     "Message-Id: %s\n", mi->message_id);
821                 return 1;
822         }
823
824         strbuf_addbuf(&mi->log_message, line);
825         return 0;
826 }
827
828 static void handle_patch(struct mailinfo *mi, const struct strbuf *line)
829 {
830         fwrite(line->buf, 1, line->len, mi->patchfile);
831         mi->patch_lines++;
832 }
833
834 static void handle_filter(struct mailinfo *mi, struct strbuf *line)
835 {
836         switch (mi->filter_stage) {
837         case 0:
838                 if (!handle_commit_msg(mi, line))
839                         break;
840                 mi->filter_stage++;
841                 /* fallthrough */
842         case 1:
843                 handle_patch(mi, line);
844                 break;
845         }
846 }
847
848 static int is_rfc2822_header(const struct strbuf *line)
849 {
850         /*
851          * The section that defines the loosest possible
852          * field name is "3.6.8 Optional fields".
853          *
854          * optional-field = field-name ":" unstructured CRLF
855          * field-name = 1*ftext
856          * ftext = %d33-57 / %59-126
857          */
858         int ch;
859         char *cp = line->buf;
860
861         /* Count mbox From headers as headers */
862         if (starts_with(cp, "From ") || starts_with(cp, ">From "))
863                 return 1;
864
865         while ((ch = *cp++)) {
866                 if (ch == ':')
867                         return 1;
868                 if ((33 <= ch && ch <= 57) ||
869                     (59 <= ch && ch <= 126))
870                         continue;
871                 break;
872         }
873         return 0;
874 }
875
876 static int read_one_header_line(struct strbuf *line, FILE *in)
877 {
878         struct strbuf continuation = STRBUF_INIT;
879
880         /* Get the first part of the line. */
881         if (strbuf_getline_lf(line, in))
882                 return 0;
883
884         /*
885          * Is it an empty line or not a valid rfc2822 header?
886          * If so, stop here, and return false ("not a header")
887          */
888         strbuf_rtrim(line);
889         if (!line->len || !is_rfc2822_header(line)) {
890                 /* Re-add the newline */
891                 strbuf_addch(line, '\n');
892                 return 0;
893         }
894
895         /*
896          * Now we need to eat all the continuation lines..
897          * Yuck, 2822 header "folding"
898          */
899         for (;;) {
900                 int peek;
901
902                 peek = fgetc(in);
903                 if (peek == EOF)
904                         break;
905                 ungetc(peek, in);
906                 if (peek != ' ' && peek != '\t')
907                         break;
908                 if (strbuf_getline_lf(&continuation, in))
909                         break;
910                 continuation.buf[0] = ' ';
911                 strbuf_rtrim(&continuation);
912                 strbuf_addbuf(line, &continuation);
913         }
914         strbuf_release(&continuation);
915
916         return 1;
917 }
918
919 static int find_boundary(struct mailinfo *mi, struct strbuf *line)
920 {
921         while (!strbuf_getline_lf(line, mi->input)) {
922                 if (*(mi->content_top) && is_multipart_boundary(mi, line))
923                         return 1;
924         }
925         return 0;
926 }
927
928 static int handle_boundary(struct mailinfo *mi, struct strbuf *line)
929 {
930         struct strbuf newline = STRBUF_INIT;
931
932         strbuf_addch(&newline, '\n');
933 again:
934         if (line->len >= (*(mi->content_top))->len + 2 &&
935             !memcmp(line->buf + (*(mi->content_top))->len, "--", 2)) {
936                 /* we hit an end boundary */
937                 /* pop the current boundary off the stack */
938                 strbuf_release(*(mi->content_top));
939                 FREE_AND_NULL(*(mi->content_top));
940
941                 /* technically won't happen as is_multipart_boundary()
942                    will fail first.  But just in case..
943                  */
944                 if (--mi->content_top < mi->content) {
945                         error("Detected mismatched boundaries, can't recover");
946                         mi->input_error = -1;
947                         mi->content_top = mi->content;
948                         strbuf_release(&newline);
949                         return 0;
950                 }
951                 handle_filter(mi, &newline);
952                 strbuf_release(&newline);
953                 if (mi->input_error)
954                         return 0;
955
956                 /* skip to the next boundary */
957                 if (!find_boundary(mi, line))
958                         return 0;
959                 goto again;
960         }
961
962         /* set some defaults */
963         mi->transfer_encoding = TE_DONTCARE;
964         strbuf_reset(&mi->charset);
965
966         /* slurp in this section's info */
967         while (read_one_header_line(line, mi->input))
968                 check_header(mi, line, mi->p_hdr_data, 0);
969
970         strbuf_release(&newline);
971         /* replenish line */
972         if (strbuf_getline_lf(line, mi->input))
973                 return 0;
974         strbuf_addch(line, '\n');
975         return 1;
976 }
977
978 static void handle_filter_flowed(struct mailinfo *mi, struct strbuf *line,
979                                  struct strbuf *prev)
980 {
981         size_t len = line->len;
982         const char *rest;
983
984         if (!mi->format_flowed) {
985                 handle_filter(mi, line);
986                 return;
987         }
988
989         if (line->buf[len - 1] == '\n') {
990                 len--;
991                 if (len && line->buf[len - 1] == '\r')
992                         len--;
993         }
994
995         /* Keep signature separator as-is. */
996         if (skip_prefix(line->buf, "-- ", &rest) && rest - line->buf == len) {
997                 if (prev->len) {
998                         handle_filter(mi, prev);
999                         strbuf_reset(prev);
1000                 }
1001                 handle_filter(mi, line);
1002                 return;
1003         }
1004
1005         /* Unstuff space-stuffed line. */
1006         if (len && line->buf[0] == ' ') {
1007                 strbuf_remove(line, 0, 1);
1008                 len--;
1009         }
1010
1011         /* Save flowed line for later, but without the soft line break. */
1012         if (len && line->buf[len - 1] == ' ') {
1013                 strbuf_add(prev, line->buf, len - !!mi->delsp);
1014                 return;
1015         }
1016
1017         /* Prepend any previous partial lines */
1018         strbuf_insert(line, 0, prev->buf, prev->len);
1019         strbuf_reset(prev);
1020
1021         handle_filter(mi, line);
1022 }
1023
1024 static void handle_body(struct mailinfo *mi, struct strbuf *line)
1025 {
1026         struct strbuf prev = STRBUF_INIT;
1027
1028         /* Skip up to the first boundary */
1029         if (*(mi->content_top)) {
1030                 if (!find_boundary(mi, line))
1031                         goto handle_body_out;
1032         }
1033
1034         do {
1035                 /* process any boundary lines */
1036                 if (*(mi->content_top) && is_multipart_boundary(mi, line)) {
1037                         /* flush any leftover */
1038                         if (prev.len) {
1039                                 handle_filter(mi, &prev);
1040                                 strbuf_reset(&prev);
1041                         }
1042                         if (!handle_boundary(mi, line))
1043                                 goto handle_body_out;
1044                 }
1045
1046                 /* Unwrap transfer encoding */
1047                 decode_transfer_encoding(mi, line);
1048
1049                 switch (mi->transfer_encoding) {
1050                 case TE_BASE64:
1051                 case TE_QP:
1052                 {
1053                         struct strbuf **lines, **it, *sb;
1054
1055                         /* Prepend any previous partial lines */
1056                         strbuf_insert(line, 0, prev.buf, prev.len);
1057                         strbuf_reset(&prev);
1058
1059                         /*
1060                          * This is a decoded line that may contain
1061                          * multiple new lines.  Pass only one chunk
1062                          * at a time to handle_filter()
1063                          */
1064                         lines = strbuf_split(line, '\n');
1065                         for (it = lines; (sb = *it); it++) {
1066                                 if (*(it + 1) == NULL) /* The last line */
1067                                         if (sb->buf[sb->len - 1] != '\n') {
1068                                                 /* Partial line, save it for later. */
1069                                                 strbuf_addbuf(&prev, sb);
1070                                                 break;
1071                                         }
1072                                 handle_filter_flowed(mi, sb, &prev);
1073                         }
1074                         /*
1075                          * The partial chunk is saved in "prev" and will be
1076                          * appended by the next iteration of read_line_with_nul().
1077                          */
1078                         strbuf_list_free(lines);
1079                         break;
1080                 }
1081                 default:
1082                         handle_filter_flowed(mi, line, &prev);
1083                 }
1084
1085                 if (mi->input_error)
1086                         break;
1087         } while (!strbuf_getwholeline(line, mi->input, '\n'));
1088
1089         if (prev.len)
1090                 handle_filter(mi, &prev);
1091
1092         flush_inbody_header_accum(mi);
1093
1094 handle_body_out:
1095         strbuf_release(&prev);
1096 }
1097
1098 static void output_header_lines(FILE *fout, const char *hdr, const struct strbuf *data)
1099 {
1100         const char *sp = data->buf;
1101         while (1) {
1102                 char *ep = strchr(sp, '\n');
1103                 int len;
1104                 if (!ep)
1105                         len = strlen(sp);
1106                 else
1107                         len = ep - sp;
1108                 fprintf(fout, "%s: %.*s\n", hdr, len, sp);
1109                 if (!ep)
1110                         break;
1111                 sp = ep + 1;
1112         }
1113 }
1114
1115 static void handle_info(struct mailinfo *mi)
1116 {
1117         struct strbuf *hdr;
1118         int i;
1119
1120         for (i = 0; header[i]; i++) {
1121                 /* only print inbody headers if we output a patch file */
1122                 if (mi->patch_lines && mi->s_hdr_data[i])
1123                         hdr = mi->s_hdr_data[i];
1124                 else if (mi->p_hdr_data[i])
1125                         hdr = mi->p_hdr_data[i];
1126                 else
1127                         continue;
1128
1129                 if (!strcmp(header[i], "Subject")) {
1130                         if (!mi->keep_subject) {
1131                                 cleanup_subject(mi, hdr);
1132                                 cleanup_space(hdr);
1133                         }
1134                         output_header_lines(mi->output, "Subject", hdr);
1135                 } else if (!strcmp(header[i], "From")) {
1136                         cleanup_space(hdr);
1137                         handle_from(mi, hdr);
1138                         fprintf(mi->output, "Author: %s\n", mi->name.buf);
1139                         fprintf(mi->output, "Email: %s\n", mi->email.buf);
1140                 } else {
1141                         cleanup_space(hdr);
1142                         fprintf(mi->output, "%s: %s\n", header[i], hdr->buf);
1143                 }
1144         }
1145         fprintf(mi->output, "\n");
1146 }
1147
1148 int mailinfo(struct mailinfo *mi, const char *msg, const char *patch)
1149 {
1150         FILE *cmitmsg;
1151         int peek;
1152         struct strbuf line = STRBUF_INIT;
1153
1154         cmitmsg = fopen(msg, "w");
1155         if (!cmitmsg) {
1156                 perror(msg);
1157                 return -1;
1158         }
1159         mi->patchfile = fopen(patch, "w");
1160         if (!mi->patchfile) {
1161                 perror(patch);
1162                 fclose(cmitmsg);
1163                 return -1;
1164         }
1165
1166         mi->p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*(mi->p_hdr_data)));
1167         mi->s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*(mi->s_hdr_data)));
1168
1169         do {
1170                 peek = fgetc(mi->input);
1171                 if (peek == EOF) {
1172                         fclose(cmitmsg);
1173                         return error("empty patch: '%s'", patch);
1174                 }
1175         } while (isspace(peek));
1176         ungetc(peek, mi->input);
1177
1178         /* process the email header */
1179         while (read_one_header_line(&line, mi->input))
1180                 check_header(mi, &line, mi->p_hdr_data, 1);
1181
1182         handle_body(mi, &line);
1183         fwrite(mi->log_message.buf, 1, mi->log_message.len, cmitmsg);
1184         fclose(cmitmsg);
1185         fclose(mi->patchfile);
1186
1187         handle_info(mi);
1188         strbuf_release(&line);
1189         return mi->input_error;
1190 }
1191
1192 static int git_mailinfo_config(const char *var, const char *value, void *mi_)
1193 {
1194         struct mailinfo *mi = mi_;
1195
1196         if (!starts_with(var, "mailinfo."))
1197                 return git_default_config(var, value, NULL);
1198         if (!strcmp(var, "mailinfo.scissors")) {
1199                 mi->use_scissors = git_config_bool(var, value);
1200                 return 0;
1201         }
1202         /* perhaps others here */
1203         return 0;
1204 }
1205
1206 void setup_mailinfo(struct mailinfo *mi)
1207 {
1208         memset(mi, 0, sizeof(*mi));
1209         strbuf_init(&mi->name, 0);
1210         strbuf_init(&mi->email, 0);
1211         strbuf_init(&mi->charset, 0);
1212         strbuf_init(&mi->log_message, 0);
1213         strbuf_init(&mi->inbody_header_accum, 0);
1214         mi->header_stage = 1;
1215         mi->use_inbody_headers = 1;
1216         mi->content_top = mi->content;
1217         git_config(git_mailinfo_config, mi);
1218 }
1219
1220 void clear_mailinfo(struct mailinfo *mi)
1221 {
1222         int i;
1223
1224         strbuf_release(&mi->name);
1225         strbuf_release(&mi->email);
1226         strbuf_release(&mi->charset);
1227         strbuf_release(&mi->inbody_header_accum);
1228         free(mi->message_id);
1229
1230         if (mi->p_hdr_data)
1231                 for (i = 0; mi->p_hdr_data[i]; i++)
1232                         strbuf_release(mi->p_hdr_data[i]);
1233         free(mi->p_hdr_data);
1234         if (mi->s_hdr_data)
1235                 for (i = 0; mi->s_hdr_data[i]; i++)
1236                         strbuf_release(mi->s_hdr_data[i]);
1237         free(mi->s_hdr_data);
1238
1239         while (mi->content < mi->content_top) {
1240                 free(*(mi->content_top));
1241                 mi->content_top--;
1242         }
1243
1244         strbuf_release(&mi->log_message);
1245 }