Merge branch 'maint-1.6.0' into maint-1.6.1
[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
29 #define MAX_HDR_PARSED 10
30 #define MAX_BOUNDARIES 5
31
32 static void get_sane_name(struct strbuf *out, struct strbuf *name, struct strbuf *email)
33 {
34         struct strbuf *src = name;
35         if (name->len < 3 || 60 < name->len || strchr(name->buf, '@') ||
36                 strchr(name->buf, '<') || strchr(name->buf, '>'))
37                 src = email;
38         else if (name == out)
39                 return;
40         strbuf_reset(out);
41         strbuf_addbuf(out, src);
42 }
43
44 static void parse_bogus_from(const struct strbuf *line)
45 {
46         /* John Doe <johndoe> */
47
48         char *bra, *ket;
49         /* This is fallback, so do not bother if we already have an
50          * e-mail address.
51          */
52         if (email.len)
53                 return;
54
55         bra = strchr(line->buf, '<');
56         if (!bra)
57                 return;
58         ket = strchr(bra, '>');
59         if (!ket)
60                 return;
61
62         strbuf_reset(&email);
63         strbuf_add(&email, bra + 1, ket - bra - 1);
64
65         strbuf_reset(&name);
66         strbuf_add(&name, line->buf, bra - line->buf);
67         strbuf_trim(&name);
68         get_sane_name(&name, &name, &email);
69 }
70
71 static void handle_from(const struct strbuf *from)
72 {
73         char *at;
74         size_t el;
75         struct strbuf f;
76
77         strbuf_init(&f, from->len);
78         strbuf_addbuf(&f, from);
79
80         at = strchr(f.buf, '@');
81         if (!at) {
82                 parse_bogus_from(from);
83                 return;
84         }
85
86         /*
87          * If we already have one email, don't take any confusing lines
88          */
89         if (email.len && strchr(at + 1, '@')) {
90                 strbuf_release(&f);
91                 return;
92         }
93
94         /* Pick up the string around '@', possibly delimited with <>
95          * pair; that is the email part.
96          */
97         while (at > f.buf) {
98                 char c = at[-1];
99                 if (isspace(c))
100                         break;
101                 if (c == '<') {
102                         at[-1] = ' ';
103                         break;
104                 }
105                 at--;
106         }
107         el = strcspn(at, " \n\t\r\v\f>");
108         strbuf_reset(&email);
109         strbuf_add(&email, at, el);
110         strbuf_remove(&f, at - f.buf, el + (at[el] ? 1 : 0));
111
112         /* The remainder is name.  It could be "John Doe <john.doe@xz>"
113          * or "john.doe@xz (John Doe)", but we have removed the
114          * email part, so trim from both ends, possibly removing
115          * the () pair at the end.
116          */
117         strbuf_trim(&f);
118         if (f.buf[0] == '(' && f.len && f.buf[f.len - 1] == ')') {
119                 strbuf_remove(&f, 0, 1);
120                 strbuf_setlen(&f, f.len - 1);
121         }
122
123         get_sane_name(&name, &f, &email);
124         strbuf_release(&f);
125 }
126
127 static void handle_header(struct strbuf **out, const struct strbuf *line)
128 {
129         if (!*out) {
130                 *out = xmalloc(sizeof(struct strbuf));
131                 strbuf_init(*out, line->len);
132         } else
133                 strbuf_reset(*out);
134
135         strbuf_addbuf(*out, line);
136 }
137
138 /* NOTE NOTE NOTE.  We do not claim we do full MIME.  We just attempt
139  * to have enough heuristics to grok MIME encoded patches often found
140  * on our mailing lists.  For example, we do not even treat header lines
141  * case insensitively.
142  */
143
144 static int slurp_attr(const char *line, const char *name, struct strbuf *attr)
145 {
146         const char *ends, *ap = strcasestr(line, name);
147         size_t sz;
148
149         if (!ap) {
150                 strbuf_setlen(attr, 0);
151                 return 0;
152         }
153         ap += strlen(name);
154         if (*ap == '"') {
155                 ap++;
156                 ends = "\"";
157         }
158         else
159                 ends = "; \t";
160         sz = strcspn(ap, ends);
161         strbuf_add(attr, ap, sz);
162         return 1;
163 }
164
165 static struct strbuf *content[MAX_BOUNDARIES];
166
167 static struct strbuf **content_top = content;
168
169 static void handle_content_type(struct strbuf *line)
170 {
171         struct strbuf *boundary = xmalloc(sizeof(struct strbuf));
172         strbuf_init(boundary, line->len);
173
174         if (!strcasestr(line->buf, "text/"))
175                  message_type = TYPE_OTHER;
176         if (slurp_attr(line->buf, "boundary=", boundary)) {
177                 strbuf_insert(boundary, 0, "--", 2);
178                 if (++content_top > &content[MAX_BOUNDARIES]) {
179                         fprintf(stderr, "Too many boundaries to handle\n");
180                         exit(1);
181                 }
182                 *content_top = boundary;
183                 boundary = NULL;
184         }
185         if (slurp_attr(line->buf, "charset=", &charset))
186                 strbuf_tolower(&charset);
187
188         if (boundary) {
189                 strbuf_release(boundary);
190                 free(boundary);
191         }
192 }
193
194 static void handle_content_transfer_encoding(const struct strbuf *line)
195 {
196         if (strcasestr(line->buf, "base64"))
197                 transfer_encoding = TE_BASE64;
198         else if (strcasestr(line->buf, "quoted-printable"))
199                 transfer_encoding = TE_QP;
200         else
201                 transfer_encoding = TE_DONTCARE;
202 }
203
204 static int is_multipart_boundary(const struct strbuf *line)
205 {
206         return (((*content_top)->len <= line->len) &&
207                 !memcmp(line->buf, (*content_top)->buf, (*content_top)->len));
208 }
209
210 static void cleanup_subject(struct strbuf *subject)
211 {
212         char *pos;
213         size_t remove;
214         while (subject->len) {
215                 switch (*subject->buf) {
216                 case 'r': case 'R':
217                         if (subject->len <= 3)
218                                 break;
219                         if (!memcmp(subject->buf + 1, "e:", 2)) {
220                                 strbuf_remove(subject, 0, 3);
221                                 continue;
222                         }
223                         break;
224                 case ' ': case '\t': case ':':
225                         strbuf_remove(subject, 0, 1);
226                         continue;
227                 case '[':
228                         if ((pos = strchr(subject->buf, ']'))) {
229                                 remove = pos - subject->buf;
230                                 if (remove <= (subject->len - remove) * 2) {
231                                         strbuf_remove(subject, 0, remove + 1);
232                                         continue;
233                                 }
234                         } else
235                                 strbuf_remove(subject, 0, 1);
236                         break;
237                 }
238                 strbuf_trim(subject);
239                 return;
240         }
241 }
242
243 static void cleanup_space(struct strbuf *sb)
244 {
245         size_t pos, cnt;
246         for (pos = 0; pos < sb->len; pos++) {
247                 if (isspace(sb->buf[pos])) {
248                         sb->buf[pos] = ' ';
249                         for (cnt = 0; isspace(sb->buf[pos + cnt + 1]); cnt++);
250                         strbuf_remove(sb, pos + 1, cnt);
251                 }
252         }
253 }
254
255 static void decode_header(struct strbuf *line);
256 static const char *header[MAX_HDR_PARSED] = {
257         "From","Subject","Date",
258 };
259
260 static inline int cmp_header(const struct strbuf *line, const char *hdr)
261 {
262         int len = strlen(hdr);
263         return !strncasecmp(line->buf, hdr, len) && line->len > len &&
264                         line->buf[len] == ':' && isspace(line->buf[len + 1]);
265 }
266
267 static int check_header(const struct strbuf *line,
268                                 struct strbuf *hdr_data[], int overwrite)
269 {
270         int i, ret = 0, len;
271         struct strbuf sb = STRBUF_INIT;
272         /* search for the interesting parts */
273         for (i = 0; header[i]; i++) {
274                 int len = strlen(header[i]);
275                 if ((!hdr_data[i] || overwrite) && cmp_header(line, header[i])) {
276                         /* Unwrap inline B and Q encoding, and optionally
277                          * normalize the meta information to utf8.
278                          */
279                         strbuf_add(&sb, line->buf + len + 2, line->len - len - 2);
280                         decode_header(&sb);
281                         handle_header(&hdr_data[i], &sb);
282                         ret = 1;
283                         goto check_header_out;
284                 }
285         }
286
287         /* Content stuff */
288         if (cmp_header(line, "Content-Type")) {
289                 len = strlen("Content-Type: ");
290                 strbuf_add(&sb, line->buf + len, line->len - len);
291                 decode_header(&sb);
292                 strbuf_insert(&sb, 0, "Content-Type: ", len);
293                 handle_content_type(&sb);
294                 ret = 1;
295                 goto check_header_out;
296         }
297         if (cmp_header(line, "Content-Transfer-Encoding")) {
298                 len = strlen("Content-Transfer-Encoding: ");
299                 strbuf_add(&sb, line->buf + len, line->len - len);
300                 decode_header(&sb);
301                 handle_content_transfer_encoding(&sb);
302                 ret = 1;
303                 goto check_header_out;
304         }
305
306         /* for inbody stuff */
307         if (!prefixcmp(line->buf, ">From") && isspace(line->buf[5])) {
308                 ret = 1; /* Should this return 0? */
309                 goto check_header_out;
310         }
311         if (!prefixcmp(line->buf, "[PATCH]") && isspace(line->buf[7])) {
312                 for (i = 0; header[i]; i++) {
313                         if (!memcmp("Subject", header[i], 7)) {
314                                 handle_header(&hdr_data[i], line);
315                                 ret = 1;
316                                 goto check_header_out;
317                         }
318                 }
319         }
320
321 check_header_out:
322         strbuf_release(&sb);
323         return ret;
324 }
325
326 static int is_rfc2822_header(const struct strbuf *line)
327 {
328         /*
329          * The section that defines the loosest possible
330          * field name is "3.6.8 Optional fields".
331          *
332          * optional-field = field-name ":" unstructured CRLF
333          * field-name = 1*ftext
334          * ftext = %d33-57 / %59-126
335          */
336         int ch;
337         char *cp = line->buf;
338
339         /* Count mbox From headers as headers */
340         if (!prefixcmp(cp, "From ") || !prefixcmp(cp, ">From "))
341                 return 1;
342
343         while ((ch = *cp++)) {
344                 if (ch == ':')
345                         return 1;
346                 if ((33 <= ch && ch <= 57) ||
347                     (59 <= ch && ch <= 126))
348                         continue;
349                 break;
350         }
351         return 0;
352 }
353
354 static int read_one_header_line(struct strbuf *line, FILE *in)
355 {
356         /* Get the first part of the line. */
357         if (strbuf_getline(line, in, '\n'))
358                 return 0;
359
360         /*
361          * Is it an empty line or not a valid rfc2822 header?
362          * If so, stop here, and return false ("not a header")
363          */
364         strbuf_rtrim(line);
365         if (!line->len || !is_rfc2822_header(line)) {
366                 /* Re-add the newline */
367                 strbuf_addch(line, '\n');
368                 return 0;
369         }
370
371         /*
372          * Now we need to eat all the continuation lines..
373          * Yuck, 2822 header "folding"
374          */
375         for (;;) {
376                 int peek;
377                 struct strbuf continuation = STRBUF_INIT;
378
379                 peek = fgetc(in); ungetc(peek, in);
380                 if (peek != ' ' && peek != '\t')
381                         break;
382                 if (strbuf_getline(&continuation, in, '\n'))
383                         break;
384                 continuation.buf[0] = '\n';
385                 strbuf_rtrim(&continuation);
386                 strbuf_addbuf(line, &continuation);
387         }
388
389         return 1;
390 }
391
392 static struct strbuf *decode_q_segment(const struct strbuf *q_seg, int rfc2047)
393 {
394         const char *in = q_seg->buf;
395         int c;
396         struct strbuf *out = xmalloc(sizeof(struct strbuf));
397         strbuf_init(out, q_seg->len);
398
399         while ((c = *in++) != 0) {
400                 if (c == '=') {
401                         int d = *in++;
402                         if (d == '\n' || !d)
403                                 break; /* drop trailing newline */
404                         strbuf_addch(out, (hexval(d) << 4) | hexval(*in++));
405                         continue;
406                 }
407                 if (rfc2047 && c == '_') /* rfc2047 4.2 (2) */
408                         c = 0x20;
409                 strbuf_addch(out, c);
410         }
411         return out;
412 }
413
414 static struct strbuf *decode_b_segment(const struct strbuf *b_seg)
415 {
416         /* Decode in..ep, possibly in-place to ot */
417         int c, pos = 0, acc = 0;
418         const char *in = b_seg->buf;
419         struct strbuf *out = xmalloc(sizeof(struct strbuf));
420         strbuf_init(out, b_seg->len);
421
422         while ((c = *in++) != 0) {
423                 if (c == '+')
424                         c = 62;
425                 else if (c == '/')
426                         c = 63;
427                 else if ('A' <= c && c <= 'Z')
428                         c -= 'A';
429                 else if ('a' <= c && c <= 'z')
430                         c -= 'a' - 26;
431                 else if ('0' <= c && c <= '9')
432                         c -= '0' - 52;
433                 else
434                         continue; /* garbage */
435                 switch (pos++) {
436                 case 0:
437                         acc = (c << 2);
438                         break;
439                 case 1:
440                         strbuf_addch(out, (acc | (c >> 4)));
441                         acc = (c & 15) << 4;
442                         break;
443                 case 2:
444                         strbuf_addch(out, (acc | (c >> 2)));
445                         acc = (c & 3) << 6;
446                         break;
447                 case 3:
448                         strbuf_addch(out, (acc | c));
449                         acc = pos = 0;
450                         break;
451                 }
452         }
453         return out;
454 }
455
456 /*
457  * When there is no known charset, guess.
458  *
459  * Right now we assume that if the target is UTF-8 (the default),
460  * and it already looks like UTF-8 (which includes US-ASCII as its
461  * subset, of course) then that is what it is and there is nothing
462  * to do.
463  *
464  * Otherwise, we default to assuming it is Latin1 for historical
465  * reasons.
466  */
467 static const char *guess_charset(const struct strbuf *line, const char *target_charset)
468 {
469         if (is_encoding_utf8(target_charset)) {
470                 if (is_utf8(line->buf))
471                         return NULL;
472         }
473         return "latin1";
474 }
475
476 static void convert_to_utf8(struct strbuf *line, const char *charset)
477 {
478         char *out;
479
480         if (!charset || !*charset) {
481                 charset = guess_charset(line, metainfo_charset);
482                 if (!charset)
483                         return;
484         }
485
486         if (!strcmp(metainfo_charset, charset))
487                 return;
488         out = reencode_string(line->buf, metainfo_charset, charset);
489         if (!out)
490                 die("cannot convert from %s to %s\n",
491                     charset, metainfo_charset);
492         strbuf_attach(line, out, strlen(out), strlen(out));
493 }
494
495 static int decode_header_bq(struct strbuf *it)
496 {
497         char *in, *ep, *cp;
498         struct strbuf outbuf = STRBUF_INIT, *dec;
499         struct strbuf charset_q = STRBUF_INIT, piecebuf = STRBUF_INIT;
500         int rfc2047 = 0;
501
502         in = it->buf;
503         while (in - it->buf <= it->len && (ep = strstr(in, "=?")) != NULL) {
504                 int encoding;
505                 strbuf_reset(&charset_q);
506                 strbuf_reset(&piecebuf);
507                 rfc2047 = 1;
508
509                 if (in != ep) {
510                         /*
511                          * We are about to process an encoded-word
512                          * that begins at ep, but there is something
513                          * before the encoded word.
514                          */
515                         char *scan;
516                         for (scan = in; scan < ep; scan++)
517                                 if (!isspace(*scan))
518                                         break;
519
520                         if (scan != ep || in == it->buf) {
521                                 /*
522                                  * We should not lose that "something",
523                                  * unless we have just processed an
524                                  * encoded-word, and there is only LWS
525                                  * before the one we are about to process.
526                                  */
527                                 strbuf_add(&outbuf, in, ep - in);
528                         }
529                         in = ep;
530                 }
531                 /* E.g.
532                  * ep : "=?iso-2022-jp?B?GyR...?= foo"
533                  * ep : "=?ISO-8859-1?Q?Foo=FCbar?= baz"
534                  */
535                 ep += 2;
536
537                 if (ep - it->buf >= it->len || !(cp = strchr(ep, '?')))
538                         goto decode_header_bq_out;
539
540                 if (cp + 3 - it->buf > it->len)
541                         goto decode_header_bq_out;
542                 strbuf_add(&charset_q, ep, cp - ep);
543                 strbuf_tolower(&charset_q);
544
545                 encoding = cp[1];
546                 if (!encoding || cp[2] != '?')
547                         goto decode_header_bq_out;
548                 ep = strstr(cp + 3, "?=");
549                 if (!ep)
550                         goto decode_header_bq_out;
551                 strbuf_add(&piecebuf, cp + 3, ep - cp - 3);
552                 switch (tolower(encoding)) {
553                 default:
554                         goto decode_header_bq_out;
555                 case 'b':
556                         dec = decode_b_segment(&piecebuf);
557                         break;
558                 case 'q':
559                         dec = decode_q_segment(&piecebuf, 1);
560                         break;
561                 }
562                 if (metainfo_charset)
563                         convert_to_utf8(dec, charset_q.buf);
564
565                 strbuf_addbuf(&outbuf, dec);
566                 strbuf_release(dec);
567                 free(dec);
568                 in = ep + 2;
569         }
570         strbuf_addstr(&outbuf, in);
571         strbuf_reset(it);
572         strbuf_addbuf(it, &outbuf);
573 decode_header_bq_out:
574         strbuf_release(&outbuf);
575         strbuf_release(&charset_q);
576         strbuf_release(&piecebuf);
577         return rfc2047;
578 }
579
580 static void decode_header(struct strbuf *it)
581 {
582         if (decode_header_bq(it))
583                 return;
584         /* otherwise "it" is a straight copy of the input.
585          * This can be binary guck but there is no charset specified.
586          */
587         if (metainfo_charset)
588                 convert_to_utf8(it, "");
589 }
590
591 static void decode_transfer_encoding(struct strbuf *line)
592 {
593         struct strbuf *ret;
594
595         switch (transfer_encoding) {
596         case TE_QP:
597                 ret = decode_q_segment(line, 0);
598                 break;
599         case TE_BASE64:
600                 ret = decode_b_segment(line);
601                 break;
602         case TE_DONTCARE:
603         default:
604                 return;
605         }
606         strbuf_reset(line);
607         strbuf_addbuf(line, ret);
608         strbuf_release(ret);
609         free(ret);
610 }
611
612 static void handle_filter(struct strbuf *line);
613
614 static int find_boundary(void)
615 {
616         while (!strbuf_getline(&line, fin, '\n')) {
617                 if (*content_top && is_multipart_boundary(&line))
618                         return 1;
619         }
620         return 0;
621 }
622
623 static int handle_boundary(void)
624 {
625         struct strbuf newline = STRBUF_INIT;
626
627         strbuf_addch(&newline, '\n');
628 again:
629         if (line.len >= (*content_top)->len + 2 &&
630             !memcmp(line.buf + (*content_top)->len, "--", 2)) {
631                 /* we hit an end boundary */
632                 /* pop the current boundary off the stack */
633                 strbuf_release(*content_top);
634                 free(*content_top);
635                 *content_top = NULL;
636
637                 /* technically won't happen as is_multipart_boundary()
638                    will fail first.  But just in case..
639                  */
640                 if (--content_top < content) {
641                         fprintf(stderr, "Detected mismatched boundaries, "
642                                         "can't recover\n");
643                         exit(1);
644                 }
645                 handle_filter(&newline);
646                 strbuf_release(&newline);
647
648                 /* skip to the next boundary */
649                 if (!find_boundary())
650                         return 0;
651                 goto again;
652         }
653
654         /* set some defaults */
655         transfer_encoding = TE_DONTCARE;
656         strbuf_reset(&charset);
657         message_type = TYPE_TEXT;
658
659         /* slurp in this section's info */
660         while (read_one_header_line(&line, fin))
661                 check_header(&line, p_hdr_data, 0);
662
663         strbuf_release(&newline);
664         /* replenish line */
665         if (strbuf_getline(&line, fin, '\n'))
666                 return 0;
667         strbuf_addch(&line, '\n');
668         return 1;
669 }
670
671 static inline int patchbreak(const struct strbuf *line)
672 {
673         size_t i;
674
675         /* Beginning of a "diff -" header? */
676         if (!prefixcmp(line->buf, "diff -"))
677                 return 1;
678
679         /* CVS "Index: " line? */
680         if (!prefixcmp(line->buf, "Index: "))
681                 return 1;
682
683         /*
684          * "--- <filename>" starts patches without headers
685          * "---<sp>*" is a manual separator
686          */
687         if (line->len < 4)
688                 return 0;
689
690         if (!prefixcmp(line->buf, "---")) {
691                 /* space followed by a filename? */
692                 if (line->buf[3] == ' ' && !isspace(line->buf[4]))
693                         return 1;
694                 /* Just whitespace? */
695                 for (i = 3; i < line->len; i++) {
696                         unsigned char c = line->buf[i];
697                         if (c == '\n')
698                                 return 1;
699                         if (!isspace(c))
700                                 break;
701                 }
702                 return 0;
703         }
704         return 0;
705 }
706
707 static int handle_commit_msg(struct strbuf *line)
708 {
709         static int still_looking = 1;
710
711         if (!cmitmsg)
712                 return 0;
713
714         if (still_looking) {
715                 strbuf_ltrim(line);
716                 if (!line->len)
717                         return 0;
718                 if ((still_looking = check_header(line, s_hdr_data, 0)) != 0)
719                         return 0;
720         }
721
722         /* normalize the log message to UTF-8. */
723         if (metainfo_charset)
724                 convert_to_utf8(line, charset.buf);
725
726         if (patchbreak(line)) {
727                 fclose(cmitmsg);
728                 cmitmsg = NULL;
729                 return 1;
730         }
731
732         fputs(line->buf, cmitmsg);
733         return 0;
734 }
735
736 static void handle_patch(const struct strbuf *line)
737 {
738         fwrite(line->buf, 1, line->len, patchfile);
739         patch_lines++;
740 }
741
742 static void handle_filter(struct strbuf *line)
743 {
744         static int filter = 0;
745
746         /* filter tells us which part we left off on */
747         switch (filter) {
748         case 0:
749                 if (!handle_commit_msg(line))
750                         break;
751                 filter++;
752         case 1:
753                 handle_patch(line);
754                 break;
755         }
756 }
757
758 static void handle_body(void)
759 {
760         int len = 0;
761         struct strbuf prev = STRBUF_INIT;
762
763         /* Skip up to the first boundary */
764         if (*content_top) {
765                 if (!find_boundary())
766                         goto handle_body_out;
767         }
768
769         do {
770                 strbuf_setlen(&line, line.len + len);
771
772                 /* process any boundary lines */
773                 if (*content_top && is_multipart_boundary(&line)) {
774                         /* flush any leftover */
775                         if (prev.len) {
776                                 handle_filter(&prev);
777                                 strbuf_reset(&prev);
778                         }
779                         if (!handle_boundary())
780                                 goto handle_body_out;
781                 }
782
783                 /* Unwrap transfer encoding */
784                 decode_transfer_encoding(&line);
785
786                 switch (transfer_encoding) {
787                 case TE_BASE64:
788                 case TE_QP:
789                 {
790                         struct strbuf **lines, **it, *sb;
791
792                         /* Prepend any previous partial lines */
793                         strbuf_insert(&line, 0, prev.buf, prev.len);
794                         strbuf_reset(&prev);
795
796                         /* binary data most likely doesn't have newlines */
797                         if (message_type != TYPE_TEXT) {
798                                 handle_filter(&line);
799                                 break;
800                         }
801                         /*
802                          * This is a decoded line that may contain
803                          * multiple new lines.  Pass only one chunk
804                          * at a time to handle_filter()
805                          */
806                         lines = strbuf_split(&line, '\n');
807                         for (it = lines; (sb = *it); it++) {
808                                 if (*(it + 1) == NULL) /* The last line */
809                                         if (sb->buf[sb->len - 1] != '\n') {
810                                                 /* Partial line, save it for later. */
811                                                 strbuf_addbuf(&prev, sb);
812                                                 break;
813                                         }
814                                 handle_filter(sb);
815                         }
816                         /*
817                          * The partial chunk is saved in "prev" and will be
818                          * appended by the next iteration of read_line_with_nul().
819                          */
820                         strbuf_list_free(lines);
821                         break;
822                 }
823                 default:
824                         handle_filter(&line);
825                 }
826
827                 strbuf_reset(&line);
828                 if (strbuf_avail(&line) < 100)
829                         strbuf_grow(&line, 100);
830         } while ((len = read_line_with_nul(line.buf, strbuf_avail(&line), fin)));
831
832 handle_body_out:
833         strbuf_release(&prev);
834 }
835
836 static void output_header_lines(FILE *fout, const char *hdr, const struct strbuf *data)
837 {
838         const char *sp = data->buf;
839         while (1) {
840                 char *ep = strchr(sp, '\n');
841                 int len;
842                 if (!ep)
843                         len = strlen(sp);
844                 else
845                         len = ep - sp;
846                 fprintf(fout, "%s: %.*s\n", hdr, len, sp);
847                 if (!ep)
848                         break;
849                 sp = ep + 1;
850         }
851 }
852
853 static void handle_info(void)
854 {
855         struct strbuf *hdr;
856         int i;
857
858         for (i = 0; header[i]; i++) {
859                 /* only print inbody headers if we output a patch file */
860                 if (patch_lines && s_hdr_data[i])
861                         hdr = s_hdr_data[i];
862                 else if (p_hdr_data[i])
863                         hdr = p_hdr_data[i];
864                 else
865                         continue;
866
867                 if (!memcmp(header[i], "Subject", 7)) {
868                         if (!keep_subject) {
869                                 cleanup_subject(hdr);
870                                 cleanup_space(hdr);
871                         }
872                         output_header_lines(fout, "Subject", hdr);
873                 } else if (!memcmp(header[i], "From", 4)) {
874                         cleanup_space(hdr);
875                         handle_from(hdr);
876                         fprintf(fout, "Author: %s\n", name.buf);
877                         fprintf(fout, "Email: %s\n", email.buf);
878                 } else {
879                         cleanup_space(hdr);
880                         fprintf(fout, "%s: %s\n", header[i], hdr->buf);
881                 }
882         }
883         fprintf(fout, "\n");
884 }
885
886 static int mailinfo(FILE *in, FILE *out, int ks, const char *encoding,
887                     const char *msg, const char *patch)
888 {
889         int peek;
890         keep_subject = ks;
891         metainfo_charset = encoding;
892         fin = in;
893         fout = out;
894
895         cmitmsg = fopen(msg, "w");
896         if (!cmitmsg) {
897                 perror(msg);
898                 return -1;
899         }
900         patchfile = fopen(patch, "w");
901         if (!patchfile) {
902                 perror(patch);
903                 fclose(cmitmsg);
904                 return -1;
905         }
906
907         p_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*p_hdr_data));
908         s_hdr_data = xcalloc(MAX_HDR_PARSED, sizeof(*s_hdr_data));
909
910         do {
911                 peek = fgetc(in);
912         } while (isspace(peek));
913         ungetc(peek, in);
914
915         /* process the email header */
916         while (read_one_header_line(&line, fin))
917                 check_header(&line, p_hdr_data, 1);
918
919         handle_body();
920         handle_info();
921
922         return 0;
923 }
924
925 static const char mailinfo_usage[] =
926         "git mailinfo [-k] [-u | --encoding=<encoding> | -n] msg patch <mail >info";
927
928 int cmd_mailinfo(int argc, const char **argv, const char *prefix)
929 {
930         const char *def_charset;
931
932         /* NEEDSWORK: might want to do the optional .git/ directory
933          * discovery
934          */
935         git_config(git_default_config, NULL);
936
937         def_charset = (git_commit_encoding ? git_commit_encoding : "utf-8");
938         metainfo_charset = def_charset;
939
940         while (1 < argc && argv[1][0] == '-') {
941                 if (!strcmp(argv[1], "-k"))
942                         keep_subject = 1;
943                 else if (!strcmp(argv[1], "-u"))
944                         metainfo_charset = def_charset;
945                 else if (!strcmp(argv[1], "-n"))
946                         metainfo_charset = NULL;
947                 else if (!prefixcmp(argv[1], "--encoding="))
948                         metainfo_charset = argv[1] + 11;
949                 else
950                         usage(mailinfo_usage);
951                 argc--; argv++;
952         }
953
954         if (argc != 3)
955                 usage(mailinfo_usage);
956
957         return !!mailinfo(stdin, stdout, keep_subject, metainfo_charset, argv[1], argv[2]);
958 }