Merge branch 'jn/block-sha1'
[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                                 /*
256                                  * If the input had a space after the ], keep
257                                  * it.  We don't bother with finding the end of
258                                  * the space, since we later normalize it
259                                  * anyway.
260                                  */
261                                 if (isspace(subject->buf[at]))
262                                         at += 1;
263                         }
264                         continue;
265                 }
266                 break;
267         }
268         strbuf_trim(subject);
269 }
270
271 static void cleanup_space(struct strbuf *sb)
272 {
273         size_t pos, cnt;
274         for (pos = 0; pos < sb->len; pos++) {
275                 if (isspace(sb->buf[pos])) {
276                         sb->buf[pos] = ' ';
277                         for (cnt = 0; isspace(sb->buf[pos + cnt + 1]); cnt++);
278                         strbuf_remove(sb, pos + 1, cnt);
279                 }
280         }
281 }
282
283 static void decode_header(struct strbuf *line);
284 static const char *header[MAX_HDR_PARSED] = {
285         "From","Subject","Date",
286 };
287
288 static inline int cmp_header(const struct strbuf *line, const char *hdr)
289 {
290         int len = strlen(hdr);
291         return !strncasecmp(line->buf, hdr, len) && line->len > len &&
292                         line->buf[len] == ':' && isspace(line->buf[len + 1]);
293 }
294
295 static int check_header(const struct strbuf *line,
296                                 struct strbuf *hdr_data[], int overwrite)
297 {
298         int i, ret = 0, len;
299         struct strbuf sb = STRBUF_INIT;
300         /* search for the interesting parts */
301         for (i = 0; header[i]; i++) {
302                 int len = strlen(header[i]);
303                 if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
304                         /* Unwrap inline B and Q encoding, and optionally
305                          * normalize the meta information to utf8.
306                          */
307                         strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
308                         decode_header(&sb);
309                         handle_header(&hdr_data[i], &sb);
310                         ret = 1;
311                         goto check_header_out;
312                 }
313         }
314
315         /* Content stuff */
316         if (cmp_header(line, "Content-Type")) {
317                 len = strlen("Content-Type: ");
318                 strbuf_add(&sb, line->buf + len, line->len - len);
319                 decode_header(&sb);
320                 strbuf_insert(&sb, 0, "Content-Type: ", len);
321                 handle_content_type(&sb);
322                 ret = 1;
323                 goto check_header_out;
324         }
325         if (cmp_header(line, "Content-Transfer-Encoding")) {
326                 len = strlen("Content-Transfer-Encoding: ");
327                 strbuf_add(&sb, line->buf + len, line->len - len);
328                 decode_header(&sb);
329                 handle_content_transfer_encoding(&sb);
330                 ret = 1;
331                 goto check_header_out;
332         }
333
334         /* for inbody stuff */
335         if (!prefixcmp(line->buf, ">From") && isspace(line->buf[5])) {
336                 ret = 1; /* Should this return 0? */
337                 goto check_header_out;
338         }
339         if (!prefixcmp(line->buf, "[PATCH]") && isspace(line->buf[7])) {
340                 for (i = 0; header[i]; i++) {
341                         if (!memcmp("Subject", header[i], 7)) {
342                                 handle_header(&hdr_data[i], line);
343                                 ret = 1;
344                                 goto check_header_out;
345                         }
346                 }
347         }
348
349 check_header_out:
350         strbuf_release(&sb);
351         return ret;
352 }
353
354 static int is_rfc2822_header(const struct strbuf *line)
355 {
356         /*
357          * The section that defines the loosest possible
358          * field name is "3.6.8 Optional fields".
359          *
360          * optional-field = field-name ":" unstructured CRLF
361          * field-name = 1*ftext
362          * ftext = %d33-57 / %59-126
363          */
364         int ch;
365         char *cp = line->buf;
366
367         /* Count mbox From headers as headers */
368         if (!prefixcmp(cp, "From ") || !prefixcmp(cp, ">From "))
369                 return 1;
370
371         while ((ch = *cp++)) {
372                 if (ch == ':')
373                         return 1;
374                 if ((33 <= ch && ch <= 57) ||
375                     (59 <= ch && ch <= 126))
376                         continue;
377                 break;
378         }
379         return 0;
380 }
381
382 static int read_one_header_line(struct strbuf *line, FILE *in)
383 {
384         /* Get the first part of the line. */
385         if (strbuf_getline(line, in, '\n'))
386                 return 0;
387
388         /*
389          * Is it an empty line or not a valid rfc2822 header?
390          * If so, stop here, and return false ("not a header")
391          */
392         strbuf_rtrim(line);
393         if (!line->len || !is_rfc2822_header(line)) {
394                 /* Re-add the newline */
395                 strbuf_addch(line, '\n');
396                 return 0;
397         }
398
399         /*
400          * Now we need to eat all the continuation lines..
401          * Yuck, 2822 header "folding"
402          */
403         for (;;) {
404                 int peek;
405                 struct strbuf continuation = STRBUF_INIT;
406
407                 peek = fgetc(in); ungetc(peek, in);
408                 if (peek != ' ' && peek != '\t')
409                         break;
410                 if (strbuf_getline(&continuation, in, '\n'))
411                         break;
412                 continuation.buf[0] = ' ';
413                 strbuf_rtrim(&continuation);
414                 strbuf_addbuf(line, &continuation);
415         }
416
417         return 1;
418 }
419
420 static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
421 {
422         const char *in = q_seg->buf;
423         int c;
424         struct strbuf *out = xmalloc(sizeof(struct strbuf));
425         strbuf_init(out, q_seg->len);
426
427         while ((c = *in++) != 0) {
428                 if (c == '=') {
429                         int d = *in++;
430                         if (d == '\n' || !d)
431                                 break; /* drop trailing newline */
432                         strbuf_addch(out, (hexval(d) << 4) | hexval(*in++));
433                         continue;
434                 }
435                 if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
436                         c = 0x20;
437                 strbuf_addch(out, c);
438         }
439         return out;
440 }
441
442 static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
443 {
444         /* Decode in..ep, possibly in-place to ot */
445         int c, pos = 0, acc = 0;
446         const char *in = b_seg->buf;
447         struct strbuf *out = xmalloc(sizeof(struct strbuf));
448         strbuf_init(out, b_seg->len);
449
450         while ((c = *in++) != 0) {
451                 if (c == '+')
452                         c = 62;
453                 else if (c == '/')
454                         c = 63;
455                 else if ('A' <= c && c <= 'Z')
456                         c -= 'A';
457                 else if ('a' <= c && c <= 'z')
458                         c -= 'a' - 26;
459                 else if ('0' <= c && c <= '9')
460                         c -= '0' - 52;
461                 else
462                         continue; /* garbage */
463                 switch (pos++) {
464                 case 0:
465                         acc = (c << 2);
466                         break;
467                 case 1:
468                         strbuf_addch(out, (acc | (c >> 4)));
469                         acc = (c & 15) << 4;
470                         break;
471                 case 2:
472                         strbuf_addch(out, (acc | (c >> 2)));
473                         acc = (c & 3) << 6;
474                         break;
475                 case 3:
476                         strbuf_addch(out, (acc | c));
477                         acc = pos = 0;
478                         break;
479                 }
480         }
481         return out;
482 }
483
484 /*
485  * When there is no known charset, guess.
486  *
487  * Right now we assume that if the target is UTF-8 (the default),
488  * and it already looks like UTF-8 (which includes US-ASCII as its
489  * subset, of course) then that is what it is and there is nothing
490  * to do.
491  *
492  * Otherwise, we default to assuming it is Latin1 for historical
493  * reasons.
494  */
495 static const char *guess_charset(const struct strbuf *line, const char *target_charset)
496 {
497         if (is_encoding_utf8(target_charset)) {
498                 if (is_utf8(line->buf))
499                         return NULL;
500         }
501         return "ISO8859-1";
502 }
503
504 static void convert_to_utf8(struct strbuf *line, const char *charset)
505 {
506         char *out;
507
508         if (!charset || !*charset) {
509                 charset = guess_charset(line, metainfo_charset);
510                 if (!charset)
511                         return;
512         }
513
514         if (!strcasecmp(metainfo_charset, charset))
515                 return;
516         out = reencode_string(line->buf, metainfo_charset, charset);
517         if (!out)
518                 die("cannot convert from %s to %s",
519                     charset, metainfo_charset);
520         strbuf_attach(line, out, strlen(out), strlen(out));
521 }
522
523 static int decode_header_bq(struct strbuf *it)
524 {
525         char *in, *ep, *cp;
526         struct strbuf outbuf = STRBUF_INIT, *dec;
527         struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
528         int rfc2047 = 0;
529
530         in = it->buf;
531         while (in - it->buf <= it->len && (ep = strstr(in, "=?")) != NULL) {
532                 int encoding;
533                 strbuf_reset(&charset_q);
534                 strbuf_reset(&piecebuf);
535                 rfc2047 = 1;
536
537                 if (in != ep) {
538                         /*
539                          * We are about to process an encoded-word
540                          * that begins at ep, but there is something
541                          * before the encoded word.
542                          */
543                         char *scan;
544                         for (scan = in; scan < ep; scan++)
545                                 if (!isspace(*scan))
546                                         break;
547
548                         if (scan != ep || in == it->buf) {
549                                 /*
550                                  * We should not lose that "something",
551                                  * unless we have just processed an
552                                  * encoded-word, and there is only LWS
553                                  * before the one we are about to process.
554                                  */
555                                 strbuf_add(&outbuf, in, ep - in);
556                         }
557                 }
558                 /* E.g.
559                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
560                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
561                  */
562                 ep += 2;
563
564                 if (ep - it->buf >= it->len || !(cp = strchr(ep, '?')))
565                         goto decode_header_bq_out;
566
567                 if (cp + 3 - it->buf > it->len)
568                         goto decode_header_bq_out;
569                 strbuf_add(&charset_q, ep, cp - ep);
570
571                 encoding = cp[1];
572                 if (!encoding || cp[2] != '?')
573                         goto decode_header_bq_out;
574                 ep = strstr(cp + 3, "?=");
575                 if (!ep)
576                         goto decode_header_bq_out;
577                 strbuf_add(&piecebuf, cp + 3, ep - cp - 3);
578                 switch (tolower(encoding)) {
579                 default:
580                         goto decode_header_bq_out;
581                 case 'b':
582                         dec = decode_b_segment(&piecebuf);
583                         break;
584                 case 'q':
585                         dec = decode_q_segment(&piecebuf, 1);
586                         break;
587                 }
588                 if (metainfo_charset)
589                         convert_to_utf8(dec, charset_q.buf);
590
591                 strbuf_addbuf(&outbuf, dec);
592                 strbuf_release(dec);
593                 free(dec);
594                 in = ep + 2;
595         }
596         strbuf_addstr(&outbuf, in);
597         strbuf_reset(it);
598         strbuf_addbuf(it, &outbuf);
599 decode_header_bq_out:
600         strbuf_release(&outbuf);
601         strbuf_release(&charset_q);
602         strbuf_release(&piecebuf);
603         return rfc2047;
604 }
605
606 static void decode_header(struct strbuf *it)
607 {
608         if (decode_header_bq(it))
609                 return;
610         /* otherwise "it" is a straight copy of the input.
611          * This can be binary guck but there is no charset specified.
612          */
613         if (metainfo_charset)
614                 convert_to_utf8(it, "");
615 }
616
617 static void decode_transfer_encoding(struct strbuf *line)
618 {
619         struct strbuf *ret;
620
621         switch (transfer_encoding) {
622         case TE_QP:
623                 ret = decode_q_segment(line, 0);
624                 break;
625         case TE_BASE64:
626                 ret = decode_b_segment(line);
627                 break;
628         case TE_DONTCARE:
629         default:
630                 return;
631         }
632         strbuf_reset(line);
633         strbuf_addbuf(line, ret);
634         strbuf_release(ret);
635         free(ret);
636 }
637
638 static void handle_filter(struct strbuf *line);
639
640 static int find_boundary(void)
641 {
642         while (!strbuf_getline(&line, fin, '\n')) {
643                 if (*content_top && is_multipart_boundary(&line))
644                         return 1;
645         }
646         return 0;
647 }
648
649 static int handle_boundary(void)
650 {
651         struct strbuf newline = STRBUF_INIT;
652
653         strbuf_addch(&newline, '\n');
654 again:
655         if (line.len >= (*content_top)->len + 2 &&
656             !memcmp(line.buf + (*content_top)->len, "--", 2)) {
657                 /* we hit an end boundary */
658                 /* pop the current boundary off the stack */
659                 strbuf_release(*content_top);
660                 free(*content_top);
661                 *content_top = NULL;
662
663                 /* technically won't happen as is_multipart_boundary()
664                    will fail first.  But just in case..
665                  */
666                 if (--content_top < content) {
667                         fprintf(stderr, "Detected mismatched boundaries, "
668                                         "can't recover\n");
669                         exit(1);
670                 }
671                 handle_filter(&newline);
672                 strbuf_release(&newline);
673
674                 /* skip to the next boundary */
675                 if (!find_boundary())
676                         return 0;
677                 goto again;
678         }
679
680         /* set some defaults */
681         transfer_encoding = TE_DONTCARE;
682         strbuf_reset(&charset);
683         message_type = TYPE_TEXT;
684
685         /* slurp in this section's info */
686         while (read_one_header_line(&line, fin))
687                 check_header(&line, p_hdr_data, 0);
688
689         strbuf_release(&newline);
690         /* replenish line */
691         if (strbuf_getline(&line, fin, '\n'))
692                 return 0;
693         strbuf_addch(&line, '\n');
694         return 1;
695 }
696
697 static inline int patchbreak(const struct strbuf *line)
698 {
699         size_t i;
700
701         /* Beginning of a "diff -" header? */
702         if (!prefixcmp(line->buf, "diff -"))
703                 return 1;
704
705         /* CVS "Index: " line? */
706         if (!prefixcmp(line->buf, "Index: "))
707                 return 1;
708
709         /*
710          * "--- <filename>" starts patches without headers
711          * "---<sp>*" is a manual separator
712          */
713         if (line->len < 4)
714                 return 0;
715
716         if (!prefixcmp(line->buf, "---")) {
717                 /* space followed by a filename? */
718                 if (line->buf[3] == ' ' && !isspace(line->buf[4]))
719                         return 1;
720                 /* Just whitespace? */
721                 for (i = 3; i < line->len; i++) {
722                         unsigned char c = line->buf[i];
723                         if (c == '\n')
724                                 return 1;
725                         if (!isspace(c))
726                                 break;
727                 }
728                 return 0;
729         }
730         return 0;
731 }
732
733 static int is_scissors_line(const struct strbuf *line)
734 {
735         size_t i, len = line->len;
736         int scissors = 0, gap = 0;
737         int first_nonblank = -1;
738         int last_nonblank = 0, visible, perforation = 0, in_perforation = 0;
739         const char *buf = line->buf;
740
741         for (i = 0; i < len; i++) {
742                 if (isspace(buf[i])) {
743                         if (in_perforation) {
744                                 perforation++;
745                                 gap++;
746                         }
747                         continue;
748                 }
749                 last_nonblank = i;
750                 if (first_nonblank < 0)
751                         first_nonblank = i;
752                 if (buf[i] == '-') {
753                         in_perforation = 1;
754                         perforation++;
755                         continue;
756                 }
757                 if (i + 1 < len &&
758                     (!memcmp(buf + i, ">8", 2) || !memcmp(buf + i, "8<", 2) ||
759                      !memcmp(buf + i, ">%", 2) || !memcmp(buf + i, "%<", 2))) {
760                         in_perforation = 1;
761                         perforation += 2;
762                         scissors += 2;
763                         i++;
764                         continue;
765                 }
766                 in_perforation = 0;
767         }
768
769         /*
770          * The mark must be at least 8 bytes long (e.g. "-- >8 --").
771          * Even though there can be arbitrary cruft on the same line
772          * (e.g. "cut here"), in order to avoid misidentification, the
773          * perforation must occupy more than a third of the visible
774          * width of the line, and dashes and scissors must occupy more
775          * than half of the perforation.
776          */
777
778         visible = last_nonblank - first_nonblank + 1;
779         return (scissors && 8 <= visible &&
780                 visible < perforation * 3 &&
781                 gap * 2 < perforation);
782 }
783
784 static int handle_commit_msg(struct strbuf *line)
785 {
786         static int still_looking = 1;
787
788         if (!cmitmsg)
789                 return 0;
790
791         if (still_looking) {
792                 if (!line->len || (line->len == 1 && line->buf[0] == '\n'))
793                         return 0;
794         }
795
796         if (use_inbody_headers && still_looking) {
797                 still_looking = check_header(line, s_hdr_data, 0);
798                 if (still_looking)
799                         return 0;
800         } else
801                 /* Only trim the first (blank) line of the commit message
802                  * when ignoring in-body headers.
803                  */
804                 still_looking = 0;
805
806         /* normalize the log message to UTF-8. */
807         if (metainfo_charset)
808                 convert_to_utf8(line, charset.buf);
809
810         if (use_scissors && is_scissors_line(line)) {
811                 int i;
812                 if (fseek(cmitmsg, 0L, SEEK_SET))
813                         die_errno("Could not rewind output message file");
814                 if (ftruncate(fileno(cmitmsg), 0))
815                         die_errno("Could not truncate output message file at scissors");
816                 still_looking = 1;
817
818                 /*
819                  * We may have already read "secondary headers"; purge
820                  * them to give ourselves a clean restart.
821                  */
822                 for (i = 0; header[i]; i++) {
823                         if (s_hdr_data[i])
824                                 strbuf_release(s_hdr_data[i]);
825                         s_hdr_data[i] = NULL;
826                 }
827                 return 0;
828         }
829
830         if (patchbreak(line)) {
831                 fclose(cmitmsg);
832                 cmitmsg = NULL;
833                 return 1;
834         }
835
836         fputs(line->buf, cmitmsg);
837         return 0;
838 }
839
840 static void handle_patch(const struct strbuf *line)
841 {
842         fwrite(line->buf, 1, line->len, patchfile);
843         patch_lines++;
844 }
845
846 static void handle_filter(struct strbuf *line)
847 {
848         static int filter = 0;
849
850         /* filter tells us which part we left off on */
851         switch (filter) {
852         case 0:
853                 if (!handle_commit_msg(line))
854                         break;
855                 filter++;
856         case 1:
857                 handle_patch(line);
858                 break;
859         }
860 }
861
862 static void handle_body(void)
863 {
864         struct strbuf prev = STRBUF_INIT;
865
866         /* Skip up to the first boundary */
867         if (*content_top) {
868                 if (!find_boundary())
869                         goto handle_body_out;
870         }
871
872         do {
873                 /* process any boundary lines */
874                 if (*content_top && is_multipart_boundary(&line)) {
875                         /* flush any leftover */
876                         if (prev.len) {
877                                 handle_filter(&prev);
878                                 strbuf_reset(&prev);
879                         }
880                         if (!handle_boundary())
881                                 goto handle_body_out;
882                 }
883
884                 /* Unwrap transfer encoding */
885                 decode_transfer_encoding(&line);
886
887                 switch (transfer_encoding) {
888                 case TE_BASE64:
889                 case TE_QP:
890                 {
891                         struct strbuf **lines, **it, *sb;
892
893                         /* Prepend any previous partial lines */
894                         strbuf_insert(&line, 0, prev.buf, prev.len);
895                         strbuf_reset(&prev);
896
897                         /* binary data most likely doesn't have newlines */
898                         if (message_type != TYPE_TEXT) {
899                                 handle_filter(&line);
900                                 break;
901                         }
902                         /*
903                          * This is a decoded line that may contain
904                          * multiple new lines.  Pass only one chunk
905                          * at a time to handle_filter()
906                          */
907                         lines = strbuf_split(&line, '\n');
908                         for (it = lines; (sb = *it); it++) {
909                                 if (*(it + 1) == NULL) /* The last line */
910                                         if (sb->buf[sb->len - 1] != '\n') {
911                                                 /* Partial line, save it for later. */
912                                                 strbuf_addbuf(&prev, sb);
913                                                 break;
914                                         }
915                                 handle_filter(sb);
916                         }
917                         /*
918                          * The partial chunk is saved in "prev" and will be
919                          * appended by the next iteration of read_line_with_nul().
920                          */
921                         strbuf_list_free(lines);
922                         break;
923                 }
924                 default:
925                         handle_filter(&line);
926                 }
927
928         } while (!strbuf_getwholeline(&line, fin, '\n'));
929
930 handle_body_out:
931         strbuf_release(&prev);
932 }
933
934 static void output_header_lines(FILE *fout, const char *hdr, const struct strbuf *data)
935 {
936         const char *sp = data->buf;
937         while (1) {
938                 char *ep = strchr(sp, '\n');
939                 int len;
940                 if (!ep)
941                         len = strlen(sp);
942                 else
943                         len = ep - sp;
944                 fprintf(fout, "%s: %.*s\n", hdr, len, sp);
945                 if (!ep)
946                         break;
947                 sp = ep + 1;
948         }
949 }
950
951 static void handle_info(void)
952 {
953         struct strbuf *hdr;
954         int i;
955
956         for (i = 0; header[i]; i++) {
957                 /* only print inbody headers if we output a patch file */
958                 if (patch_lines && s_hdr_data[i])
959                         hdr = s_hdr_data[i];
960                 else if (p_hdr_data[i])
961                         hdr = p_hdr_data[i];
962                 else
963                         continue;
964
965                 if (!memcmp(header[i], "Subject", 7)) {
966                         if (!keep_subject) {
967                                 cleanup_subject(hdr);
968                                 cleanup_space(hdr);
969                         }
970                         output_header_lines(fout, "Subject", hdr);
971                 } else if (!memcmp(header[i], "From", 4)) {
972                         cleanup_space(hdr);
973                         handle_from(hdr);
974                         fprintf(fout, "Author: %s\n", name.buf);
975                         fprintf(fout, "Email: %s\n", email.buf);
976                 } else {
977                         cleanup_space(hdr);
978                         fprintf(fout, "%s: %s\n", header[i], hdr->buf);
979                 }
980         }
981         fprintf(fout, "\n");
982 }
983
984 static int mailinfo(FILE *in, FILE *out, const char *msg, const char *patch)
985 {
986         int peek;
987         fin = in;
988         fout = out;
989
990         cmitmsg = fopen(msg, "w");
991         if (!cmitmsg) {
992                 perror(msg);
993                 return -1;
994         }
995         patchfile = fopen(patch, "w");
996         if (!patchfile) {
997                 perror(patch);
998                 fclose(cmitmsg);
999                 return -1;
1000         }
1001
1002         p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*p_hdr_data));
1003         s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*s_hdr_data));
1004
1005         do {
1006                 peek = fgetc(in);
1007         } while (isspace(peek));
1008         ungetc(peek, in);
1009
1010         /* process the email header */
1011         while (read_one_header_line(&line, fin))
1012                 check_header(&line, p_hdr_data, 1);
1013
1014         handle_body();
1015         handle_info();
1016
1017         return 0;
1018 }
1019
1020 static int git_mailinfo_config(const char *var, const char *value, void *unused)
1021 {
1022         if (prefixcmp(var, "mailinfo."))
1023                 return git_default_config(var, value, unused);
1024         if (!strcmp(var, "mailinfo.scissors")) {
1025                 use_scissors = git_config_bool(var, value);
1026                 return 0;
1027         }
1028         /* perhaps others here */
1029         return 0;
1030 }
1031
1032 static const char mailinfo_usage[] =
1033         "git mailinfo [-k|-b] [-u | --encoding=<encoding> | -n] [--scissors | --no-scissors] msg patch < mail >info";
1034
1035 int cmd_mailinfo(int argc, const char **argv, const char *prefix)
1036 {
1037         const char *def_charset;
1038
1039         /* NEEDSWORK: might want to do the optional .git/ directory
1040          * discovery
1041          */
1042         git_config(git_mailinfo_config, NULL);
1043
1044         def_charset = get_commit_output_encoding();
1045         metainfo_charset = def_charset;
1046
1047         while (1 < argc && argv[1][0] == '-') {
1048                 if (!strcmp(argv[1], "-k"))
1049                         keep_subject = 1;
1050                 else if (!strcmp(argv[1], "-b"))
1051                         keep_non_patch_brackets_in_subject = 1;
1052                 else if (!strcmp(argv[1], "-u"))
1053                         metainfo_charset = def_charset;
1054                 else if (!strcmp(argv[1], "-n"))
1055                         metainfo_charset = NULL;
1056                 else if (!prefixcmp(argv[1], "--encoding="))
1057                         metainfo_charset = argv[1] + 11;
1058                 else if (!strcmp(argv[1], "--scissors"))
1059                         use_scissors = 1;
1060                 else if (!strcmp(argv[1], "--no-scissors"))
1061                         use_scissors = 0;
1062                 else if (!strcmp(argv[1], "--no-inbody-headers"))
1063                         use_inbody_headers = 0;
1064                 else
1065                         usage(mailinfo_usage);
1066                 argc--; argv++;
1067         }
1068
1069         if (argc != 3)
1070                 usage(mailinfo_usage);
1071
1072         return !!mailinfo(stdin, stdout, argv[1], argv[2]);
1073 }