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