Merge branch 'jn/maint-bundle' into maint
[git] / builtin / mailinfo.c
1 /*
2  * Another stupid program, this one parsing the headers of an
3  * email to figure out authorship and subject
4  */
5 #include "cache.h"
6 #include "builtin.h"
7 #include "utf8.h"
8 #include "strbuf.h"
9
10 static FILE *cmitmsg, *patchfile, *fin, *fout;
11
12 static int keep_subject;
13 static int keep_non_patch_brackets_in_subject;
14 static const char *metainfo_charset;
15 static struct strbuf line = STRBUF_INIT;
16 static struct strbuf name = STRBUF_INIT;
17 static struct strbuf email = STRBUF_INIT;
18
19 static enum  {
20         TE_DONTCARE, TE_QP, TE_BASE64,
21 } transfer_encoding;
22 static enum  {
23         TYPE_TEXT, TYPE_OTHER,
24 } message_type;
25
26 static struct strbuf charset = STRBUF_INIT;
27 static int patch_lines;
28 static struct strbuf **p_hdr_data, **s_hdr_data;
29 static int use_scissors;
30 static int use_inbody_headers = 1;
31
32 #define MAX_HDR_PARSED 10
33 #define MAX_BOUNDARIES 5
34
35 static void cleanup_space(struct strbuf *sb);
36
37
38 static void get_sane_name(struct strbuf *out, struct strbuf *name, struct strbuf *email)
39 {
40         struct strbuf *src = name;
41         if (name->len < 3 || 60 < name->len || strchr(name->buf, '@') ||
42                 strchr(name->buf, '<') || strchr(name->buf, '>'))
43                 src = email;
44         else if (name == out)
45                 return;
46         strbuf_reset(out);
47         strbuf_addbuf(out, src);
48 }
49
50 static void parse_bogus_from(const struct strbuf *line)
51 {
52         /* John Doe <johndoe> */
53
54         char *bra, *ket;
55         /* This is fallback, so do not bother if we already have an
56          * e-mail address.
57          */
58         if (email.len)
59                 return;
60
61         bra = strchr(line->buf, '<');
62         if (!bra)
63                 return;
64         ket = strchr(bra, '>');
65         if (!ket)
66                 return;
67
68         strbuf_reset(&email);
69         strbuf_add(&email, bra + 1, ket - bra - 1);
70
71         strbuf_reset(&name);
72         strbuf_add(&name, line->buf, bra - line->buf);
73         strbuf_trim(&name);
74         get_sane_name(&name, &name, &email);
75 }
76
77 static void handle_from(const struct strbuf *from)
78 {
79         char *at;
80         size_t el;
81         struct strbuf f;
82
83         strbuf_init(&f, from->len);
84         strbuf_addbuf(&f, from);
85
86         at = strchr(f.buf, '@');
87         if (!at) {
88                 parse_bogus_from(from);
89                 return;
90         }
91
92         /*
93          * If we already have one email, don't take any confusing lines
94          */
95         if (email.len && strchr(at + 1, '@')) {
96                 strbuf_release(&f);
97                 return;
98         }
99
100         /* Pick up the string around '@', possibly delimited with <>
101          * pair; that is the email part.
102          */
103         while (at > f.buf) {
104                 char c = at[-1];
105                 if (isspace(c))
106                         break;
107                 if (c == '<') {
108                         at[-1] = ' ';
109                         break;
110                 }
111                 at--;
112         }
113         el = strcspn(at, " \n\t\r\v\f>");
114         strbuf_reset(&email);
115         strbuf_add(&email, at, el);
116         strbuf_remove(&f, at - f.buf, el + (at[el] ? 1 : 0));
117
118         /* The remainder is name.  It could be
119          *
120          * - "John Doe <john.doe@xz>"                   (a), or
121          * - "john.doe@xz (John Doe)"                   (b), or
122          * - "John (zzz) Doe <john.doe@xz> (Comment)"   (c)
123          *
124          * but we have removed the email part, so
125          *
126          * - remove extra spaces which could stay after email (case 'c'), and
127          * - trim from both ends, possibly removing the () pair at the end
128          *   (cases 'a' and 'b').
129          */
130         cleanup_space(&f);
131         strbuf_trim(&f);
132         if (f.buf[0] == '(' && f.len && f.buf[f.len - 1] == ')') {
133                 strbuf_remove(&f, 0, 1);
134                 strbuf_setlen(&f, f.len - 1);
135         }
136
137         get_sane_name(&name, &f, &email);
138         strbuf_release(&f);
139 }
140
141 static void handle_header(struct strbuf **out, const struct strbuf *line)
142 {
143         if (!*out) {
144                 *out = xmalloc(sizeof(struct strbuf));
145                 strbuf_init(*out, line->len);
146         } else
147                 strbuf_reset(*out);
148
149         strbuf_addbuf(*out, line);
150 }
151
152 /* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
153  * to have enough heuristics to grok MIME encoded patches often found
154  * on our mailing lists.  For example, we do not even treat header lines
155  * case insensitively.
156  */
157
158 static int slurp_attr(const char *line, const char *name, struct strbuf *attr)
159 {
160         const char *ends, *ap = strcasestr(line, name);
161         size_t sz;
162
163         if (!ap) {
164                 strbuf_setlen(attr, 0);
165                 return 0;
166         }
167         ap += strlen(name);
168         if (*ap == '"') {
169                 ap++;
170                 ends = "\"";
171         }
172         else
173                 ends = "; \t";
174         sz = strcspn(ap, ends);
175         strbuf_add(attr, ap, sz);
176         return 1;
177 }
178
179 static struct strbuf *content[MAX_BOUNDARIES];
180
181 static struct strbuf **content_top = content;
182
183 static void handle_content_type(struct strbuf *line)
184 {
185         struct strbuf *boundary = xmalloc(sizeof(struct strbuf));
186         strbuf_init(boundary, line->len);
187
188         if (!strcasestr(line->buf, "text/"))
189                  message_type = TYPE_OTHER;
190         if (slurp_attr(line->buf, "boundary=", boundary)) {
191                 strbuf_insert(boundary, 0, "--", 2);
192                 if (++content_top > &content[MAX_BOUNDARIES]) {
193                         fprintf(stderr, "Too many boundaries to handle\n");
194                         exit(1);
195                 }
196                 *content_top = boundary;
197                 boundary = NULL;
198         }
199         slurp_attr(line->buf, "charset=", &charset);
200
201         if (boundary) {
202                 strbuf_release(boundary);
203                 free(boundary);
204         }
205 }
206
207 static void handle_content_transfer_encoding(const struct strbuf *line)
208 {
209         if (strcasestr(line->buf, "base64"))
210                 transfer_encoding = TE_BASE64;
211         else if (strcasestr(line->buf, "quoted-printable"))
212                 transfer_encoding = TE_QP;
213         else
214                 transfer_encoding = TE_DONTCARE;
215 }
216
217 static int is_multipart_boundary(const struct strbuf *line)
218 {
219         return (((*content_top)->len <= line->len) &&
220                 !memcmp(line->buf, (*content_top)->buf, (*content_top)->len));
221 }
222
223 static void cleanup_subject(struct strbuf *subject)
224 {
225         size_t at = 0;
226
227         while (at < subject->len) {
228                 char *pos;
229                 size_t remove;
230
231                 switch (subject->buf[at]) {
232                 case 'r': case 'R':
233                         if (subject->len <= at + 3)
234                                 break;
235                         if (!memcmp(subject->buf + at + 1, "e:", 2)) {
236                                 strbuf_remove(subject, at, 3);
237                                 continue;
238                         }
239                         at++;
240                         break;
241                 case ' ': case '\t': case ':':
242                         strbuf_remove(subject, at, 1);
243                         continue;
244                 case '[':
245                         pos = strchr(subject->buf + at, ']');
246                         if (!pos)
247                                 break;
248                         remove = pos - subject->buf + at + 1;
249                         if (!keep_non_patch_brackets_in_subject ||
250                             (7 <= remove &&
251                              memmem(subject->buf + at, remove, "PATCH", 5)))
252                                 strbuf_remove(subject, at, remove);
253                         else
254                                 at += remove;
255                         continue;
256                 }
257                 break;
258         }
259         strbuf_trim(subject);
260 }
261
262 static void cleanup_space(struct strbuf *sb)
263 {
264         size_t pos, cnt;
265         for (pos = 0; pos < sb->len; pos++) {
266                 if (isspace(sb->buf[pos])) {
267                         sb->buf[pos] = ' ';
268                         for (cnt = 0; isspace(sb->buf[pos + cnt + 1]); cnt++);
269                         strbuf_remove(sb, pos + 1, cnt);
270                 }
271         }
272 }
273
274 static void decode_header(struct strbuf *line);
275 static const char *header[MAX_HDR_PARSED] = {
276         "From","Subject","Date",
277 };
278
279 static inline int cmp_header(const struct strbuf *line, const char *hdr)
280 {
281         int len = strlen(hdr);
282         return !strncasecmp(line->buf, hdr, len) && line->len > len &&
283                         line->buf[len] == ':' && isspace(line->buf[len + 1]);
284 }
285
286 static int check_header(const struct strbuf *line,
287                                 struct strbuf *hdr_data[], int overwrite)
288 {
289         int i, ret = 0, len;
290         struct strbuf sb = STRBUF_INIT;
291         /* search for the interesting parts */
292         for (i = 0; header[i]; i++) {
293                 int len = strlen(header[i]);
294                 if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
295                         /* Unwrap inline B and Q encoding, and optionally
296                          * normalize the meta information to utf8.
297                          */
298                         strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
299                         decode_header(&sb);
300                         handle_header(&hdr_data[i], &sb);
301                         ret = 1;
302                         goto check_header_out;
303                 }
304         }
305
306         /* Content stuff */
307         if (cmp_header(line, "Content-Type")) {
308                 len = strlen("Content-Type: ");
309                 strbuf_add(&sb, line->buf + len, line->len - len);
310                 decode_header(&sb);
311                 strbuf_insert(&sb, 0, "Content-Type: ", len);
312                 handle_content_type(&sb);
313                 ret = 1;
314                 goto check_header_out;
315         }
316         if (cmp_header(line, "Content-Transfer-Encoding")) {
317                 len = strlen("Content-Transfer-Encoding: ");
318                 strbuf_add(&sb, line->buf + len, line->len - len);
319                 decode_header(&sb);
320                 handle_content_transfer_encoding(&sb);
321                 ret = 1;
322                 goto check_header_out;
323         }
324
325         /* for inbody stuff */
326         if (!prefixcmp(line->buf, ">From") && isspace(line->buf[5])) {
327                 ret = 1; /* Should this return 0? */
328                 goto check_header_out;
329         }
330         if (!prefixcmp(line->buf, "[PATCH]") && isspace(line->buf[7])) {
331                 for (i = 0; header[i]; i++) {
332                         if (!memcmp("Subject", header[i], 7)) {
333                                 handle_header(&hdr_data[i], line);
334                                 ret = 1;
335                                 goto check_header_out;
336                         }
337                 }
338         }
339
340 check_header_out:
341         strbuf_release(&sb);
342         return ret;
343 }
344
345 static int is_rfc2822_header(const struct strbuf *line)
346 {
347         /*
348          * The section that defines the loosest possible
349          * field name is "3.6.8 Optional fields".
350          *
351          * optional-field = field-name ":" unstructured CRLF
352          * field-name = 1*ftext
353          * ftext = %d33-57 / %59-126
354          */
355         int ch;
356         char *cp = line->buf;
357
358         /* Count mbox From headers as headers */
359         if (!prefixcmp(cp, "From ") || !prefixcmp(cp, ">From "))
360                 return 1;
361
362         while ((ch = *cp++)) {
363                 if (ch == ':')
364                         return 1;
365                 if ((33 <= ch && ch <= 57) ||
366                     (59 <= ch && ch <= 126))
367                         continue;
368                 break;
369         }
370         return 0;
371 }
372
373 static int read_one_header_line(struct strbuf *line, FILE *in)
374 {
375         /* Get the first part of the line. */
376         if (strbuf_getline(line, in, '\n'))
377                 return 0;
378
379         /*
380          * Is it an empty line or not a valid rfc2822 header?
381          * If so, stop here, and return false ("not a header")
382          */
383         strbuf_rtrim(line);
384         if (!line->len || !is_rfc2822_header(line)) {
385                 /* Re-add the newline */
386                 strbuf_addch(line, '\n');
387                 return 0;
388         }
389
390         /*
391          * Now we need to eat all the continuation lines..
392          * Yuck, 2822 header "folding"
393          */
394         for (;;) {
395                 int peek;
396                 struct strbuf continuation = STRBUF_INIT;
397
398                 peek = fgetc(in); ungetc(peek, in);
399                 if (peek != ' ' && peek != '\t')
400                         break;
401                 if (strbuf_getline(&continuation, in, '\n'))
402                         break;
403                 continuation.buf[0] = '\n';
404                 strbuf_rtrim(&continuation);
405                 strbuf_addbuf(line, &continuation);
406         }
407
408         return 1;
409 }
410
411 static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
412 {
413         const char *in = q_seg->buf;
414         int c;
415         struct strbuf *out = xmalloc(sizeof(struct strbuf));
416         strbuf_init(out, q_seg->len);
417
418         while ((c = *in++) != 0) {
419                 if (c == '=') {
420                         int d = *in++;
421                         if (d == '\n' || !d)
422                                 break; /* drop trailing newline */
423                         strbuf_addch(out, (hexval(d) << 4) | hexval(*in++));
424                         continue;
425                 }
426                 if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
427                         c = 0x20;
428                 strbuf_addch(out, c);
429         }
430         return out;
431 }
432
433 static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
434 {
435         /* Decode in..ep, possibly in-place to ot */
436         int c, pos = 0, acc = 0;
437         const char *in = b_seg->buf;
438         struct strbuf *out = xmalloc(sizeof(struct strbuf));
439         strbuf_init(out, b_seg->len);
440
441         while ((c = *in++) != 0) {
442                 if (c == '+')
443                         c = 62;
444                 else if (c == '/')
445                         c = 63;
446                 else if ('A' <= c && c <= 'Z')
447                         c -= 'A';
448                 else if ('a' <= c && c <= 'z')
449                         c -= 'a' - 26;
450                 else if ('0' <= c && c <= '9')
451                         c -= '0' - 52;
452                 else
453                         continue; /* garbage */
454                 switch (pos++) {
455                 case 0:
456                         acc = (c << 2);
457                         break;
458                 case 1:
459                         strbuf_addch(out, (acc | (c >> 4)));
460                         acc = (c & 15) << 4;
461                         break;
462                 case 2:
463                         strbuf_addch(out, (acc | (c >> 2)));
464                         acc = (c & 3) << 6;
465                         break;
466                 case 3:
467                         strbuf_addch(out, (acc | c));
468                         acc = pos = 0;
469                         break;
470                 }
471         }
472         return out;
473 }
474
475 /*
476  * When there is no known charset, guess.
477  *
478  * Right now we assume that if the target is UTF-8 (the default),
479  * and it already looks like UTF-8 (which includes US-ASCII as its
480  * subset, of course) then that is what it is and there is nothing
481  * to do.
482  *
483  * Otherwise, we default to assuming it is Latin1 for historical
484  * reasons.
485  */
486 static const char *guess_charset(const struct strbuf *line, const char *target_charset)
487 {
488         if (is_encoding_utf8(target_charset)) {
489                 if (is_utf8(line->buf))
490                         return NULL;
491         }
492         return "ISO8859-1";
493 }
494
495 static void convert_to_utf8(struct strbuf *line, const char *charset)
496 {
497         char *out;
498
499         if (!charset || !*charset) {
500                 charset = guess_charset(line, metainfo_charset);
501                 if (!charset)
502                         return;
503         }
504
505         if (!strcasecmp(metainfo_charset, charset))
506                 return;
507         out = reencode_string(line->buf, metainfo_charset, charset);
508         if (!out)
509                 die("cannot convert from %s to %s",
510                     charset, metainfo_charset);
511         strbuf_attach(line, out, strlen(out), strlen(out));
512 }
513
514 static int decode_header_bq(struct strbuf *it)
515 {
516         char *in, *ep, *cp;
517         struct strbuf outbuf = STRBUF_INIT, *dec;
518         struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
519         int rfc2047 = 0;
520
521         in = it->buf;
522         while (in - it->buf <= it->len && (ep = strstr(in, "=?")) != NULL) {
523                 int encoding;
524                 strbuf_reset(&charset_q);
525                 strbuf_reset(&piecebuf);
526                 rfc2047 = 1;
527
528                 if (in != ep) {
529                         /*
530                          * We are about to process an encoded-word
531                          * that begins at ep, but there is something
532                          * before the encoded word.
533                          */
534                         char *scan;
535                         for (scan = in; scan < ep; scan++)
536                                 if (!isspace(*scan))
537                                         break;
538
539                         if (scan != ep || in == it->buf) {
540                                 /*
541                                  * We should not lose that "something",
542                                  * unless we have just processed an
543                                  * encoded-word, and there is only LWS
544                                  * before the one we are about to process.
545                                  */
546                                 strbuf_add(&outbuf, in, ep - in);
547                         }
548                 }
549                 /* E.g.
550                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
551                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
552                  */
553                 ep += 2;
554
555                 if (ep - it->buf >= it->len || !(cp = strchr(ep, '?')))
556                         goto decode_header_bq_out;
557
558                 if (cp + 3 - it->buf > it->len)
559                         goto decode_header_bq_out;
560                 strbuf_add(&charset_q, ep, cp - ep);
561
562                 encoding = cp[1];
563                 if (!encoding || cp[2] != '?')
564                         goto decode_header_bq_out;
565                 ep = strstr(cp + 3, "?=");
566                 if (!ep)
567                         goto decode_header_bq_out;
568                 strbuf_add(&piecebuf, cp + 3, ep - cp - 3);
569                 switch (tolower(encoding)) {
570                 default:
571                         goto decode_header_bq_out;
572                 case 'b':
573                         dec = decode_b_segment(&piecebuf);
574                         break;
575                 case 'q':
576                         dec = decode_q_segment(&piecebuf, 1);
577                         break;
578                 }
579                 if (metainfo_charset)
580                         convert_to_utf8(dec, charset_q.buf);
581
582                 strbuf_addbuf(&outbuf, dec);
583                 strbuf_release(dec);
584                 free(dec);
585                 in = ep + 2;
586         }
587         strbuf_addstr(&outbuf, in);
588         strbuf_reset(it);
589         strbuf_addbuf(it, &outbuf);
590 decode_header_bq_out:
591         strbuf_release(&outbuf);
592         strbuf_release(&charset_q);
593         strbuf_release(&piecebuf);
594         return rfc2047;
595 }
596
597 static void decode_header(struct strbuf *it)
598 {
599         if (decode_header_bq(it))
600                 return;
601         /* otherwise "it" is a straight copy of the input.
602          * This can be binary guck but there is no charset specified.
603          */
604         if (metainfo_charset)
605                 convert_to_utf8(it, "");
606 }
607
608 static void decode_transfer_encoding(struct strbuf *line)
609 {
610         struct strbuf *ret;
611
612         switch (transfer_encoding) {
613         case TE_QP:
614                 ret = decode_q_segment(line, 0);
615                 break;
616         case TE_BASE64:
617                 ret = decode_b_segment(line);
618                 break;
619         case TE_DONTCARE:
620         default:
621                 return;
622         }
623         strbuf_reset(line);
624         strbuf_addbuf(line, ret);
625         strbuf_release(ret);
626         free(ret);
627 }
628
629 static void handle_filter(struct strbuf *line);
630
631 static int find_boundary(void)
632 {
633         while (!strbuf_getline(&line, fin, '\n')) {
634                 if (*content_top && is_multipart_boundary(&line))
635                         return 1;
636         }
637         return 0;
638 }
639
640 static int handle_boundary(void)
641 {
642         struct strbuf newline = STRBUF_INIT;
643
644         strbuf_addch(&newline, '\n');
645 again:
646         if (line.len >= (*content_top)->len + 2 &&
647             !memcmp(line.buf + (*content_top)->len, "--", 2)) {
648                 /* we hit an end boundary */
649                 /* pop the current boundary off the stack */
650                 strbuf_release(*content_top);
651                 free(*content_top);
652                 *content_top = NULL;
653
654                 /* technically won't happen as is_multipart_boundary()
655                    will fail first.  But just in case..
656                  */
657                 if (--content_top < content) {
658                         fprintf(stderr, "Detected mismatched boundaries, "
659                                         "can't recover\n");
660                         exit(1);
661                 }
662                 handle_filter(&newline);
663                 strbuf_release(&newline);
664
665                 /* skip to the next boundary */
666                 if (!find_boundary())
667                         return 0;
668                 goto again;
669         }
670
671         /* set some defaults */
672         transfer_encoding = TE_DONTCARE;
673         strbuf_reset(&charset);
674         message_type = TYPE_TEXT;
675
676         /* slurp in this section's info */
677         while (read_one_header_line(&line, fin))
678                 check_header(&line, p_hdr_data, 0);
679
680         strbuf_release(&newline);
681         /* replenish line */
682         if (strbuf_getline(&line, fin, '\n'))
683                 return 0;
684         strbuf_addch(&line, '\n');
685         return 1;
686 }
687
688 static inline int patchbreak(const struct strbuf *line)
689 {
690         size_t i;
691
692         /* Beginning of a "diff -" header? */
693         if (!prefixcmp(line->buf, "diff -"))
694                 return 1;
695
696         /* CVS "Index: " line? */
697         if (!prefixcmp(line->buf, "Index: "))
698                 return 1;
699
700         /*
701          * "--- <filename>" starts patches without headers
702          * "---<sp>*" is a manual separator
703          */
704         if (line->len < 4)
705                 return 0;
706
707         if (!prefixcmp(line->buf, "---")) {
708                 /* space followed by a filename? */
709                 if (line->buf[3] == ' ' && !isspace(line->buf[4]))
710                         return 1;
711                 /* Just whitespace? */
712                 for (i = 3; i < line->len; i++) {
713                         unsigned char c = line->buf[i];
714                         if (c == '\n')
715                                 return 1;
716                         if (!isspace(c))
717                                 break;
718                 }
719                 return 0;
720         }
721         return 0;
722 }
723
724 static int is_scissors_line(const struct strbuf *line)
725 {
726         size_t i, len = line->len;
727         int scissors = 0, gap = 0;
728         int first_nonblank = -1;
729         int last_nonblank = 0, visible, perforation = 0, in_perforation = 0;
730         const char *buf = line->buf;
731
732         for (i = 0; i < len; i++) {
733                 if (isspace(buf[i])) {
734                         if (in_perforation) {
735                                 perforation++;
736                                 gap++;
737                         }
738                         continue;
739                 }
740                 last_nonblank = i;
741                 if (first_nonblank < 0)
742                         first_nonblank = i;
743                 if (buf[i] == '-') {
744                         in_perforation = 1;
745                         perforation++;
746                         continue;
747                 }
748                 if (i + 1 < len &&
749                     (!memcmp(buf + i, ">8", 2) || !memcmp(buf + i, "8<", 2) ||
750                      !memcmp(buf + i, ">%", 2) || !memcmp(buf + i, "%<", 2))) {
751                         in_perforation = 1;
752                         perforation += 2;
753                         scissors += 2;
754                         i++;
755                         continue;
756                 }
757                 in_perforation = 0;
758         }
759
760         /*
761          * The mark must be at least 8 bytes long (e.g. "-- >8 --").
762          * Even though there can be arbitrary cruft on the same line
763          * (e.g. "cut here"), in order to avoid misidentification, the
764          * perforation must occupy more than a third of the visible
765          * width of the line, and dashes and scissors must occupy more
766          * than half of the perforation.
767          */
768
769         visible = last_nonblank - first_nonblank + 1;
770         return (scissors && 8 <= visible &&
771                 visible < perforation * 3 &&
772                 gap * 2 < perforation);
773 }
774
775 static int handle_commit_msg(struct strbuf *line)
776 {
777         static int still_looking = 1;
778
779         if (!cmitmsg)
780                 return 0;
781
782         if (still_looking) {
783                 if (!line->len || (line->len == 1 && line->buf[0] == '\n'))
784                         return 0;
785         }
786
787         if (use_inbody_headers && still_looking) {
788                 still_looking = check_header(line, s_hdr_data, 0);
789                 if (still_looking)
790                         return 0;
791         } else
792                 /* Only trim the first (blank) line of the commit message
793                  * when ignoring in-body headers.
794                  */
795                 still_looking = 0;
796
797         /* normalize the log message to UTF-8. */
798         if (metainfo_charset)
799                 convert_to_utf8(line, charset.buf);
800
801         if (use_scissors && is_scissors_line(line)) {
802                 int i;
803                 if (fseek(cmitmsg, 0L, SEEK_SET))
804                         die_errno("Could not rewind output message file");
805                 if (ftruncate(fileno(cmitmsg), 0))
806                         die_errno("Could not truncate output message file at scissors");
807                 still_looking = 1;
808
809                 /*
810                  * We may have already read "secondary headers"; purge
811                  * them to give ourselves a clean restart.
812                  */
813                 for (i = 0; header[i]; i++) {
814                         if (s_hdr_data[i])
815                                 strbuf_release(s_hdr_data[i]);
816                         s_hdr_data[i] = NULL;
817                 }
818                 return 0;
819         }
820
821         if (patchbreak(line)) {
822                 fclose(cmitmsg);
823                 cmitmsg = NULL;
824                 return 1;
825         }
826
827         fputs(line->buf, cmitmsg);
828         return 0;
829 }
830
831 static void handle_patch(const struct strbuf *line)
832 {
833         fwrite(line->buf, 1, line->len, patchfile);
834         patch_lines++;
835 }
836
837 static void handle_filter(struct strbuf *line)
838 {
839         static int filter = 0;
840
841         /* filter tells us which part we left off on */
842         switch (filter) {
843         case 0:
844                 if (!handle_commit_msg(line))
845                         break;
846                 filter++;
847         case 1:
848                 handle_patch(line);
849                 break;
850         }
851 }
852
853 static void handle_body(void)
854 {
855         struct strbuf prev = STRBUF_INIT;
856
857         /* Skip up to the first boundary */
858         if (*content_top) {
859                 if (!find_boundary())
860                         goto handle_body_out;
861         }
862
863         do {
864                 /* process any boundary lines */
865                 if (*content_top && is_multipart_boundary(&line)) {
866                         /* flush any leftover */
867                         if (prev.len) {
868                                 handle_filter(&prev);
869                                 strbuf_reset(&prev);
870                         }
871                         if (!handle_boundary())
872                                 goto handle_body_out;
873                 }
874
875                 /* Unwrap transfer encoding */
876                 decode_transfer_encoding(&line);
877
878                 switch (transfer_encoding) {
879                 case TE_BASE64:
880                 case TE_QP:
881                 {
882                         struct strbuf **lines, **it, *sb;
883
884                         /* Prepend any previous partial lines */
885                         strbuf_insert(&line, 0, prev.buf, prev.len);
886                         strbuf_reset(&prev);
887
888                         /* binary data most likely doesn't have newlines */
889                         if (message_type != TYPE_TEXT) {
890                                 handle_filter(&line);
891                                 break;
892                         }
893                         /*
894                          * This is a decoded line that may contain
895                          * multiple new lines.  Pass only one chunk
896                          * at a time to handle_filter()
897                          */
898                         lines = strbuf_split(&line, '\n');
899                         for (it = lines; (sb = *it); it++) {
900                                 if (*(it + 1) == NULL) /* The last line */
901                                         if (sb->buf[sb->len - 1] != '\n') {
902                                                 /* Partial line, save it for later. */
903                                                 strbuf_addbuf(&prev, sb);
904                                                 break;
905                                         }
906                                 handle_filter(sb);
907                         }
908                         /*
909                          * The partial chunk is saved in "prev" and will be
910                          * appended by the next iteration of read_line_with_nul().
911                          */
912                         strbuf_list_free(lines);
913                         break;
914                 }
915                 default:
916                         handle_filter(&line);
917                 }
918
919         } while (!strbuf_getwholeline(&line, fin, '\n'));
920
921 handle_body_out:
922         strbuf_release(&prev);
923 }
924
925 static void output_header_lines(FILE *fout, const char *hdr, const struct strbuf *data)
926 {
927         const char *sp = data->buf;
928         while (1) {
929                 char *ep = strchr(sp, '\n');
930                 int len;
931                 if (!ep)
932                         len = strlen(sp);
933                 else
934                         len = ep - sp;
935                 fprintf(fout, "%s: %.*s\n", hdr, len, sp);
936                 if (!ep)
937                         break;
938                 sp = ep + 1;
939         }
940 }
941
942 static void handle_info(void)
943 {
944         struct strbuf *hdr;
945         int i;
946
947         for (i = 0; header[i]; i++) {
948                 /* only print inbody headers if we output a patch file */
949                 if (patch_lines && s_hdr_data[i])
950                         hdr = s_hdr_data[i];
951                 else if (p_hdr_data[i])
952                         hdr = p_hdr_data[i];
953                 else
954                         continue;
955
956                 if (!memcmp(header[i], "Subject", 7)) {
957                         if (!keep_subject) {
958                                 cleanup_subject(hdr);
959                                 cleanup_space(hdr);
960                         }
961                         output_header_lines(fout, "Subject", hdr);
962                 } else if (!memcmp(header[i], "From", 4)) {
963                         cleanup_space(hdr);
964                         handle_from(hdr);
965                         fprintf(fout, "Author: %s\n", name.buf);
966                         fprintf(fout, "Email: %s\n", email.buf);
967                 } else {
968                         cleanup_space(hdr);
969                         fprintf(fout, "%s: %s\n", header[i], hdr->buf);
970                 }
971         }
972         fprintf(fout, "\n");
973 }
974
975 static int mailinfo(FILE *in, FILE *out, const char *msg, const char *patch)
976 {
977         int peek;
978         fin = in;
979         fout = out;
980
981         cmitmsg = fopen(msg, "w");
982         if (!cmitmsg) {
983                 perror(msg);
984                 return -1;
985         }
986         patchfile = fopen(patch, "w");
987         if (!patchfile) {
988                 perror(patch);
989                 fclose(cmitmsg);
990                 return -1;
991         }
992
993         p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*p_hdr_data));
994         s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*s_hdr_data));
995
996         do {
997                 peek = fgetc(in);
998         } while (isspace(peek));
999         ungetc(peek, in);
1000
1001         /* process the email header */
1002         while (read_one_header_line(&line, fin))
1003                 check_header(&line, p_hdr_data, 1);
1004
1005         handle_body();
1006         handle_info();
1007
1008         return 0;
1009 }
1010
1011 static int git_mailinfo_config(const char *var, const char *value, void *unused)
1012 {
1013         if (prefixcmp(var, "mailinfo."))
1014                 return git_default_config(var, value, unused);
1015         if (!strcmp(var, "mailinfo.scissors")) {
1016                 use_scissors = git_config_bool(var, value);
1017                 return 0;
1018         }
1019         /* perhaps others here */
1020         return 0;
1021 }
1022
1023 static const char mailinfo_usage[] =
1024         "git mailinfo [-k|-b] [-u | --encoding=<encoding> | -n] [--scissors | --no-scissors] msg patch < mail >info";
1025
1026 int cmd_mailinfo(int argc, const char **argv, const char *prefix)
1027 {
1028         const char *def_charset;
1029
1030         /* NEEDSWORK: might want to do the optional .git/ directory
1031          * discovery
1032          */
1033         git_config(git_mailinfo_config, NULL);
1034
1035         def_charset = (git_commit_encoding ? git_commit_encoding : "UTF-8");
1036         metainfo_charset = def_charset;
1037
1038         while (1 < argc && argv[1][0] == '-') {
1039                 if (!strcmp(argv[1], "-k"))
1040                         keep_subject = 1;
1041                 else if (!strcmp(argv[1], "-b"))
1042                         keep_non_patch_brackets_in_subject = 1;
1043                 else if (!strcmp(argv[1], "-u"))
1044                         metainfo_charset = def_charset;
1045                 else if (!strcmp(argv[1], "-n"))
1046                         metainfo_charset = NULL;
1047                 else if (!prefixcmp(argv[1], "--encoding="))
1048                         metainfo_charset = argv[1] + 11;
1049                 else if (!strcmp(argv[1], "--scissors"))
1050                         use_scissors = 1;
1051                 else if (!strcmp(argv[1], "--no-scissors"))
1052                         use_scissors = 0;
1053                 else if (!strcmp(argv[1], "--no-inbody-headers"))
1054                         use_inbody_headers = 0;
1055                 else
1056                         usage(mailinfo_usage);
1057                 argc--; argv++;
1058         }
1059
1060         if (argc != 3)
1061                 usage(mailinfo_usage);
1062
1063         return !!mailinfo(stdin, stdout, argv[1], argv[2]);
1064 }