Merge branch 'ds/blame-on-bloom'
[git] / convert.c
1 #include "cache.h"
2 #include "config.h"
3 #include "object-store.h"
4 #include "attr.h"
5 #include "run-command.h"
6 #include "quote.h"
7 #include "sigchain.h"
8 #include "pkt-line.h"
9 #include "sub-process.h"
10 #include "utf8.h"
11 #include "ll-merge.h"
12
13 /*
14  * convert.c - convert a file when checking it out and checking it in.
15  *
16  * This should use the pathname to decide on whether it wants to do some
17  * more interesting conversions (automatic gzip/unzip, general format
18  * conversions etc etc), but by default it just does automatic CRLF<->LF
19  * translation when the "text" attribute or "auto_crlf" option is set.
20  */
21
22 /* Stat bits: When BIN is set, the txt bits are unset */
23 #define CONVERT_STAT_BITS_TXT_LF    0x1
24 #define CONVERT_STAT_BITS_TXT_CRLF  0x2
25 #define CONVERT_STAT_BITS_BIN       0x4
26
27 enum crlf_action {
28         CRLF_UNDEFINED,
29         CRLF_BINARY,
30         CRLF_TEXT,
31         CRLF_TEXT_INPUT,
32         CRLF_TEXT_CRLF,
33         CRLF_AUTO,
34         CRLF_AUTO_INPUT,
35         CRLF_AUTO_CRLF
36 };
37
38 struct text_stat {
39         /* NUL, CR, LF and CRLF counts */
40         unsigned nul, lonecr, lonelf, crlf;
41
42         /* These are just approximations! */
43         unsigned printable, nonprintable;
44 };
45
46 static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
47 {
48         unsigned long i;
49
50         memset(stats, 0, sizeof(*stats));
51
52         for (i = 0; i < size; i++) {
53                 unsigned char c = buf[i];
54                 if (c == '\r') {
55                         if (i+1 < size && buf[i+1] == '\n') {
56                                 stats->crlf++;
57                                 i++;
58                         } else
59                                 stats->lonecr++;
60                         continue;
61                 }
62                 if (c == '\n') {
63                         stats->lonelf++;
64                         continue;
65                 }
66                 if (c == 127)
67                         /* DEL */
68                         stats->nonprintable++;
69                 else if (c < 32) {
70                         switch (c) {
71                                 /* BS, HT, ESC and FF */
72                         case '\b': case '\t': case '\033': case '\014':
73                                 stats->printable++;
74                                 break;
75                         case 0:
76                                 stats->nul++;
77                                 /* fall through */
78                         default:
79                                 stats->nonprintable++;
80                         }
81                 }
82                 else
83                         stats->printable++;
84         }
85
86         /* If file ends with EOF then don't count this EOF as non-printable. */
87         if (size >= 1 && buf[size-1] == '\032')
88                 stats->nonprintable--;
89 }
90
91 /*
92  * The same heuristics as diff.c::mmfile_is_binary()
93  * We treat files with bare CR as binary
94  */
95 static int convert_is_binary(const struct text_stat *stats)
96 {
97         if (stats->lonecr)
98                 return 1;
99         if (stats->nul)
100                 return 1;
101         if ((stats->printable >> 7) < stats->nonprintable)
102                 return 1;
103         return 0;
104 }
105
106 static unsigned int gather_convert_stats(const char *data, unsigned long size)
107 {
108         struct text_stat stats;
109         int ret = 0;
110         if (!data || !size)
111                 return 0;
112         gather_stats(data, size, &stats);
113         if (convert_is_binary(&stats))
114                 ret |= CONVERT_STAT_BITS_BIN;
115         if (stats.crlf)
116                 ret |= CONVERT_STAT_BITS_TXT_CRLF;
117         if (stats.lonelf)
118                 ret |=  CONVERT_STAT_BITS_TXT_LF;
119
120         return ret;
121 }
122
123 static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
124 {
125         unsigned int convert_stats = gather_convert_stats(data, size);
126
127         if (convert_stats & CONVERT_STAT_BITS_BIN)
128                 return "-text";
129         switch (convert_stats) {
130         case CONVERT_STAT_BITS_TXT_LF:
131                 return "lf";
132         case CONVERT_STAT_BITS_TXT_CRLF:
133                 return "crlf";
134         case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
135                 return "mixed";
136         default:
137                 return "none";
138         }
139 }
140
141 const char *get_cached_convert_stats_ascii(const struct index_state *istate,
142                                            const char *path)
143 {
144         const char *ret;
145         unsigned long sz;
146         void *data = read_blob_data_from_index(istate, path, &sz);
147         ret = gather_convert_stats_ascii(data, sz);
148         free(data);
149         return ret;
150 }
151
152 const char *get_wt_convert_stats_ascii(const char *path)
153 {
154         const char *ret = "";
155         struct strbuf sb = STRBUF_INIT;
156         if (strbuf_read_file(&sb, path, 0) >= 0)
157                 ret = gather_convert_stats_ascii(sb.buf, sb.len);
158         strbuf_release(&sb);
159         return ret;
160 }
161
162 static int text_eol_is_crlf(void)
163 {
164         if (auto_crlf == AUTO_CRLF_TRUE)
165                 return 1;
166         else if (auto_crlf == AUTO_CRLF_INPUT)
167                 return 0;
168         if (core_eol == EOL_CRLF)
169                 return 1;
170         if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
171                 return 1;
172         return 0;
173 }
174
175 static enum eol output_eol(enum crlf_action crlf_action)
176 {
177         switch (crlf_action) {
178         case CRLF_BINARY:
179                 return EOL_UNSET;
180         case CRLF_TEXT_CRLF:
181                 return EOL_CRLF;
182         case CRLF_TEXT_INPUT:
183                 return EOL_LF;
184         case CRLF_UNDEFINED:
185         case CRLF_AUTO_CRLF:
186                 return EOL_CRLF;
187         case CRLF_AUTO_INPUT:
188                 return EOL_LF;
189         case CRLF_TEXT:
190         case CRLF_AUTO:
191                 /* fall through */
192                 return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
193         }
194         warning(_("illegal crlf_action %d"), (int)crlf_action);
195         return core_eol;
196 }
197
198 static void check_global_conv_flags_eol(const char *path, enum crlf_action crlf_action,
199                             struct text_stat *old_stats, struct text_stat *new_stats,
200                             int conv_flags)
201 {
202         if (old_stats->crlf && !new_stats->crlf ) {
203                 /*
204                  * CRLFs would not be restored by checkout
205                  */
206                 if (conv_flags & CONV_EOL_RNDTRP_DIE)
207                         die(_("CRLF would be replaced by LF in %s"), path);
208                 else if (conv_flags & CONV_EOL_RNDTRP_WARN)
209                         warning(_("CRLF will be replaced by LF in %s.\n"
210                                   "The file will have its original line"
211                                   " endings in your working directory"), path);
212         } else if (old_stats->lonelf && !new_stats->lonelf ) {
213                 /*
214                  * CRLFs would be added by checkout
215                  */
216                 if (conv_flags & CONV_EOL_RNDTRP_DIE)
217                         die(_("LF would be replaced by CRLF in %s"), path);
218                 else if (conv_flags & CONV_EOL_RNDTRP_WARN)
219                         warning(_("LF will be replaced by CRLF in %s.\n"
220                                   "The file will have its original line"
221                                   " endings in your working directory"), path);
222         }
223 }
224
225 static int has_crlf_in_index(const struct index_state *istate, const char *path)
226 {
227         unsigned long sz;
228         void *data;
229         const char *crp;
230         int has_crlf = 0;
231
232         data = read_blob_data_from_index(istate, path, &sz);
233         if (!data)
234                 return 0;
235
236         crp = memchr(data, '\r', sz);
237         if (crp) {
238                 unsigned int ret_stats;
239                 ret_stats = gather_convert_stats(data, sz);
240                 if (!(ret_stats & CONVERT_STAT_BITS_BIN) &&
241                     (ret_stats & CONVERT_STAT_BITS_TXT_CRLF))
242                         has_crlf = 1;
243         }
244         free(data);
245         return has_crlf;
246 }
247
248 static int will_convert_lf_to_crlf(struct text_stat *stats,
249                                    enum crlf_action crlf_action)
250 {
251         if (output_eol(crlf_action) != EOL_CRLF)
252                 return 0;
253         /* No "naked" LF? Nothing to convert, regardless. */
254         if (!stats->lonelf)
255                 return 0;
256
257         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
258                 /* If we have any CR or CRLF line endings, we do not touch it */
259                 /* This is the new safer autocrlf-handling */
260                 if (stats->lonecr || stats->crlf)
261                         return 0;
262
263                 if (convert_is_binary(stats))
264                         return 0;
265         }
266         return 1;
267
268 }
269
270 static int validate_encoding(const char *path, const char *enc,
271                       const char *data, size_t len, int die_on_error)
272 {
273         const char *stripped;
274
275         /* We only check for UTF here as UTF?? can be an alias for UTF-?? */
276         if (skip_iprefix(enc, "UTF", &stripped)) {
277                 skip_prefix(stripped, "-", &stripped);
278
279                 /*
280                  * Check for detectable errors in UTF encodings
281                  */
282                 if (has_prohibited_utf_bom(enc, data, len)) {
283                         const char *error_msg = _(
284                                 "BOM is prohibited in '%s' if encoded as %s");
285                         /*
286                          * This advice is shown for UTF-??BE and UTF-??LE encodings.
287                          * We cut off the last two characters of the encoding name
288                          * to generate the encoding name suitable for BOMs.
289                          */
290                         const char *advise_msg = _(
291                                 "The file '%s' contains a byte order "
292                                 "mark (BOM). Please use UTF-%.*s as "
293                                 "working-tree-encoding.");
294                         int stripped_len = strlen(stripped) - strlen("BE");
295                         advise(advise_msg, path, stripped_len, stripped);
296                         if (die_on_error)
297                                 die(error_msg, path, enc);
298                         else {
299                                 return error(error_msg, path, enc);
300                         }
301
302                 } else if (is_missing_required_utf_bom(enc, data, len)) {
303                         const char *error_msg = _(
304                                 "BOM is required in '%s' if encoded as %s");
305                         const char *advise_msg = _(
306                                 "The file '%s' is missing a byte order "
307                                 "mark (BOM). Please use UTF-%sBE or UTF-%sLE "
308                                 "(depending on the byte order) as "
309                                 "working-tree-encoding.");
310                         advise(advise_msg, path, stripped, stripped);
311                         if (die_on_error)
312                                 die(error_msg, path, enc);
313                         else {
314                                 return error(error_msg, path, enc);
315                         }
316                 }
317
318         }
319         return 0;
320 }
321
322 static void trace_encoding(const char *context, const char *path,
323                            const char *encoding, const char *buf, size_t len)
324 {
325         static struct trace_key coe = TRACE_KEY_INIT(WORKING_TREE_ENCODING);
326         struct strbuf trace = STRBUF_INIT;
327         int i;
328
329         strbuf_addf(&trace, "%s (%s, considered %s):\n", context, path, encoding);
330         for (i = 0; i < len && buf; ++i) {
331                 strbuf_addf(
332                         &trace, "| \033[2m%2i:\033[0m %2x \033[2m%c\033[0m%c",
333                         i,
334                         (unsigned char) buf[i],
335                         (buf[i] > 32 && buf[i] < 127 ? buf[i] : ' '),
336                         ((i+1) % 8 && (i+1) < len ? ' ' : '\n')
337                 );
338         }
339         strbuf_addchars(&trace, '\n', 1);
340
341         trace_strbuf(&coe, &trace);
342         strbuf_release(&trace);
343 }
344
345 static int check_roundtrip(const char *enc_name)
346 {
347         /*
348          * check_roundtrip_encoding contains a string of comma and/or
349          * space separated encodings (eg. "UTF-16, ASCII, CP1125").
350          * Search for the given encoding in that string.
351          */
352         const char *found = strcasestr(check_roundtrip_encoding, enc_name);
353         const char *next;
354         int len;
355         if (!found)
356                 return 0;
357         next = found + strlen(enc_name);
358         len = strlen(check_roundtrip_encoding);
359         return (found && (
360                         /*
361                          * check that the found encoding is at the
362                          * beginning of check_roundtrip_encoding or
363                          * that it is prefixed with a space or comma
364                          */
365                         found == check_roundtrip_encoding || (
366                                 (isspace(found[-1]) || found[-1] == ',')
367                         )
368                 ) && (
369                         /*
370                          * check that the found encoding is at the
371                          * end of check_roundtrip_encoding or
372                          * that it is suffixed with a space or comma
373                          */
374                         next == check_roundtrip_encoding + len || (
375                                 next < check_roundtrip_encoding + len &&
376                                 (isspace(next[0]) || next[0] == ',')
377                         )
378                 ));
379 }
380
381 static const char *default_encoding = "UTF-8";
382
383 static int encode_to_git(const char *path, const char *src, size_t src_len,
384                          struct strbuf *buf, const char *enc, int conv_flags)
385 {
386         char *dst;
387         size_t dst_len;
388         int die_on_error = conv_flags & CONV_WRITE_OBJECT;
389
390         /*
391          * No encoding is specified or there is nothing to encode.
392          * Tell the caller that the content was not modified.
393          */
394         if (!enc || (src && !src_len))
395                 return 0;
396
397         /*
398          * Looks like we got called from "would_convert_to_git()".
399          * This means Git wants to know if it would encode (= modify!)
400          * the content. Let's answer with "yes", since an encoding was
401          * specified.
402          */
403         if (!buf && !src)
404                 return 1;
405
406         if (validate_encoding(path, enc, src, src_len, die_on_error))
407                 return 0;
408
409         trace_encoding("source", path, enc, src, src_len);
410         dst = reencode_string_len(src, src_len, default_encoding, enc,
411                                   &dst_len);
412         if (!dst) {
413                 /*
414                  * We could add the blob "as-is" to Git. However, on checkout
415                  * we would try to re-encode to the original encoding. This
416                  * would fail and we would leave the user with a messed-up
417                  * working tree. Let's try to avoid this by screaming loud.
418                  */
419                 const char* msg = _("failed to encode '%s' from %s to %s");
420                 if (die_on_error)
421                         die(msg, path, enc, default_encoding);
422                 else {
423                         error(msg, path, enc, default_encoding);
424                         return 0;
425                 }
426         }
427         trace_encoding("destination", path, default_encoding, dst, dst_len);
428
429         /*
430          * UTF supports lossless conversion round tripping [1] and conversions
431          * between UTF and other encodings are mostly round trip safe as
432          * Unicode aims to be a superset of all other character encodings.
433          * However, certain encodings (e.g. SHIFT-JIS) are known to have round
434          * trip issues [2]. Check the round trip conversion for all encodings
435          * listed in core.checkRoundtripEncoding.
436          *
437          * The round trip check is only performed if content is written to Git.
438          * This ensures that no information is lost during conversion to/from
439          * the internal UTF-8 representation.
440          *
441          * Please note, the code below is not tested because I was not able to
442          * generate a faulty round trip without an iconv error. Iconv errors
443          * are already caught above.
444          *
445          * [1] http://unicode.org/faq/utf_bom.html#gen2
446          * [2] https://support.microsoft.com/en-us/help/170559/prb-conversion-problem-between-shift-jis-and-unicode
447          */
448         if (die_on_error && check_roundtrip(enc)) {
449                 char *re_src;
450                 size_t re_src_len;
451
452                 re_src = reencode_string_len(dst, dst_len,
453                                              enc, default_encoding,
454                                              &re_src_len);
455
456                 trace_printf("Checking roundtrip encoding for %s...\n", enc);
457                 trace_encoding("reencoded source", path, enc,
458                                re_src, re_src_len);
459
460                 if (!re_src || src_len != re_src_len ||
461                     memcmp(src, re_src, src_len)) {
462                         const char* msg = _("encoding '%s' from %s to %s and "
463                                             "back is not the same");
464                         die(msg, path, enc, default_encoding);
465                 }
466
467                 free(re_src);
468         }
469
470         strbuf_attach(buf, dst, dst_len, dst_len + 1);
471         return 1;
472 }
473
474 static int encode_to_worktree(const char *path, const char *src, size_t src_len,
475                               struct strbuf *buf, const char *enc)
476 {
477         char *dst;
478         size_t dst_len;
479
480         /*
481          * No encoding is specified or there is nothing to encode.
482          * Tell the caller that the content was not modified.
483          */
484         if (!enc || (src && !src_len))
485                 return 0;
486
487         dst = reencode_string_len(src, src_len, enc, default_encoding,
488                                   &dst_len);
489         if (!dst) {
490                 error(_("failed to encode '%s' from %s to %s"),
491                       path, default_encoding, enc);
492                 return 0;
493         }
494
495         strbuf_attach(buf, dst, dst_len, dst_len + 1);
496         return 1;
497 }
498
499 static int crlf_to_git(const struct index_state *istate,
500                        const char *path, const char *src, size_t len,
501                        struct strbuf *buf,
502                        enum crlf_action crlf_action, int conv_flags)
503 {
504         struct text_stat stats;
505         char *dst;
506         int convert_crlf_into_lf;
507
508         if (crlf_action == CRLF_BINARY ||
509             (src && !len))
510                 return 0;
511
512         /*
513          * If we are doing a dry-run and have no source buffer, there is
514          * nothing to analyze; we must assume we would convert.
515          */
516         if (!buf && !src)
517                 return 1;
518
519         gather_stats(src, len, &stats);
520         /* Optimization: No CRLF? Nothing to convert, regardless. */
521         convert_crlf_into_lf = !!stats.crlf;
522
523         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
524                 if (convert_is_binary(&stats))
525                         return 0;
526                 /*
527                  * If the file in the index has any CR in it, do not
528                  * convert.  This is the new safer autocrlf handling,
529                  * unless we want to renormalize in a merge or
530                  * cherry-pick.
531                  */
532                 if ((!(conv_flags & CONV_EOL_RENORMALIZE)) &&
533                     has_crlf_in_index(istate, path))
534                         convert_crlf_into_lf = 0;
535         }
536         if (((conv_flags & CONV_EOL_RNDTRP_WARN) ||
537              ((conv_flags & CONV_EOL_RNDTRP_DIE) && len))) {
538                 struct text_stat new_stats;
539                 memcpy(&new_stats, &stats, sizeof(new_stats));
540                 /* simulate "git add" */
541                 if (convert_crlf_into_lf) {
542                         new_stats.lonelf += new_stats.crlf;
543                         new_stats.crlf = 0;
544                 }
545                 /* simulate "git checkout" */
546                 if (will_convert_lf_to_crlf(&new_stats, crlf_action)) {
547                         new_stats.crlf += new_stats.lonelf;
548                         new_stats.lonelf = 0;
549                 }
550                 check_global_conv_flags_eol(path, crlf_action, &stats, &new_stats, conv_flags);
551         }
552         if (!convert_crlf_into_lf)
553                 return 0;
554
555         /*
556          * At this point all of our source analysis is done, and we are sure we
557          * would convert. If we are in dry-run mode, we can give an answer.
558          */
559         if (!buf)
560                 return 1;
561
562         /* only grow if not in place */
563         if (strbuf_avail(buf) + buf->len < len)
564                 strbuf_grow(buf, len - buf->len);
565         dst = buf->buf;
566         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
567                 /*
568                  * If we guessed, we already know we rejected a file with
569                  * lone CR, and we can strip a CR without looking at what
570                  * follow it.
571                  */
572                 do {
573                         unsigned char c = *src++;
574                         if (c != '\r')
575                                 *dst++ = c;
576                 } while (--len);
577         } else {
578                 do {
579                         unsigned char c = *src++;
580                         if (! (c == '\r' && (1 < len && *src == '\n')))
581                                 *dst++ = c;
582                 } while (--len);
583         }
584         strbuf_setlen(buf, dst - buf->buf);
585         return 1;
586 }
587
588 static int crlf_to_worktree(const char *src, size_t len,
589                             struct strbuf *buf, enum crlf_action crlf_action)
590 {
591         char *to_free = NULL;
592         struct text_stat stats;
593
594         if (!len || output_eol(crlf_action) != EOL_CRLF)
595                 return 0;
596
597         gather_stats(src, len, &stats);
598         if (!will_convert_lf_to_crlf(&stats, crlf_action))
599                 return 0;
600
601         /* are we "faking" in place editing ? */
602         if (src == buf->buf)
603                 to_free = strbuf_detach(buf, NULL);
604
605         strbuf_grow(buf, len + stats.lonelf);
606         for (;;) {
607                 const char *nl = memchr(src, '\n', len);
608                 if (!nl)
609                         break;
610                 if (nl > src && nl[-1] == '\r') {
611                         strbuf_add(buf, src, nl + 1 - src);
612                 } else {
613                         strbuf_add(buf, src, nl - src);
614                         strbuf_addstr(buf, "\r\n");
615                 }
616                 len -= nl + 1 - src;
617                 src  = nl + 1;
618         }
619         strbuf_add(buf, src, len);
620
621         free(to_free);
622         return 1;
623 }
624
625 struct filter_params {
626         const char *src;
627         unsigned long size;
628         int fd;
629         const char *cmd;
630         const char *path;
631 };
632
633 static int filter_buffer_or_fd(int in, int out, void *data)
634 {
635         /*
636          * Spawn cmd and feed the buffer contents through its stdin.
637          */
638         struct child_process child_process = CHILD_PROCESS_INIT;
639         struct filter_params *params = (struct filter_params *)data;
640         int write_err, status;
641         const char *argv[] = { NULL, NULL };
642
643         /* apply % substitution to cmd */
644         struct strbuf cmd = STRBUF_INIT;
645         struct strbuf path = STRBUF_INIT;
646         struct strbuf_expand_dict_entry dict[] = {
647                 { "f", NULL, },
648                 { NULL, NULL, },
649         };
650
651         /* quote the path to preserve spaces, etc. */
652         sq_quote_buf(&path, params->path);
653         dict[0].value = path.buf;
654
655         /* expand all %f with the quoted path */
656         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
657         strbuf_release(&path);
658
659         argv[0] = cmd.buf;
660
661         child_process.argv = argv;
662         child_process.use_shell = 1;
663         child_process.in = -1;
664         child_process.out = out;
665
666         if (start_command(&child_process)) {
667                 strbuf_release(&cmd);
668                 return error(_("cannot fork to run external filter '%s'"),
669                              params->cmd);
670         }
671
672         sigchain_push(SIGPIPE, SIG_IGN);
673
674         if (params->src) {
675                 write_err = (write_in_full(child_process.in,
676                                            params->src, params->size) < 0);
677                 if (errno == EPIPE)
678                         write_err = 0;
679         } else {
680                 write_err = copy_fd(params->fd, child_process.in);
681                 if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
682                         write_err = 0;
683         }
684
685         if (close(child_process.in))
686                 write_err = 1;
687         if (write_err)
688                 error(_("cannot feed the input to external filter '%s'"),
689                       params->cmd);
690
691         sigchain_pop(SIGPIPE);
692
693         status = finish_command(&child_process);
694         if (status)
695                 error(_("external filter '%s' failed %d"), params->cmd, status);
696
697         strbuf_release(&cmd);
698         return (write_err || status);
699 }
700
701 static int apply_single_file_filter(const char *path, const char *src, size_t len, int fd,
702                                     struct strbuf *dst, const char *cmd)
703 {
704         /*
705          * Create a pipeline to have the command filter the buffer's
706          * contents.
707          *
708          * (child --> cmd) --> us
709          */
710         int err = 0;
711         struct strbuf nbuf = STRBUF_INIT;
712         struct async async;
713         struct filter_params params;
714
715         memset(&async, 0, sizeof(async));
716         async.proc = filter_buffer_or_fd;
717         async.data = &params;
718         async.out = -1;
719         params.src = src;
720         params.size = len;
721         params.fd = fd;
722         params.cmd = cmd;
723         params.path = path;
724
725         fflush(NULL);
726         if (start_async(&async))
727                 return 0;       /* error was already reported */
728
729         if (strbuf_read(&nbuf, async.out, 0) < 0) {
730                 err = error(_("read from external filter '%s' failed"), cmd);
731         }
732         if (close(async.out)) {
733                 err = error(_("read from external filter '%s' failed"), cmd);
734         }
735         if (finish_async(&async)) {
736                 err = error(_("external filter '%s' failed"), cmd);
737         }
738
739         if (!err) {
740                 strbuf_swap(dst, &nbuf);
741         }
742         strbuf_release(&nbuf);
743         return !err;
744 }
745
746 #define CAP_CLEAN    (1u<<0)
747 #define CAP_SMUDGE   (1u<<1)
748 #define CAP_DELAY    (1u<<2)
749
750 struct cmd2process {
751         struct subprocess_entry subprocess; /* must be the first member! */
752         unsigned int supported_capabilities;
753 };
754
755 static int subprocess_map_initialized;
756 static struct hashmap subprocess_map;
757
758 static int start_multi_file_filter_fn(struct subprocess_entry *subprocess)
759 {
760         static int versions[] = {2, 0};
761         static struct subprocess_capability capabilities[] = {
762                 { "clean",  CAP_CLEAN  },
763                 { "smudge", CAP_SMUDGE },
764                 { "delay",  CAP_DELAY  },
765                 { NULL, 0 }
766         };
767         struct cmd2process *entry = (struct cmd2process *)subprocess;
768         return subprocess_handshake(subprocess, "git-filter", versions, NULL,
769                                     capabilities,
770                                     &entry->supported_capabilities);
771 }
772
773 static void handle_filter_error(const struct strbuf *filter_status,
774                                 struct cmd2process *entry,
775                                 const unsigned int wanted_capability)
776 {
777         if (!strcmp(filter_status->buf, "error"))
778                 ; /* The filter signaled a problem with the file. */
779         else if (!strcmp(filter_status->buf, "abort") && wanted_capability) {
780                 /*
781                  * The filter signaled a permanent problem. Don't try to filter
782                  * files with the same command for the lifetime of the current
783                  * Git process.
784                  */
785                  entry->supported_capabilities &= ~wanted_capability;
786         } else {
787                 /*
788                  * Something went wrong with the protocol filter.
789                  * Force shutdown and restart if another blob requires filtering.
790                  */
791                 error(_("external filter '%s' failed"), entry->subprocess.cmd);
792                 subprocess_stop(&subprocess_map, &entry->subprocess);
793                 free(entry);
794         }
795 }
796
797 static int apply_multi_file_filter(const char *path, const char *src, size_t len,
798                                    int fd, struct strbuf *dst, const char *cmd,
799                                    const unsigned int wanted_capability,
800                                    const struct checkout_metadata *meta,
801                                    struct delayed_checkout *dco)
802 {
803         int err;
804         int can_delay = 0;
805         struct cmd2process *entry;
806         struct child_process *process;
807         struct strbuf nbuf = STRBUF_INIT;
808         struct strbuf filter_status = STRBUF_INIT;
809         const char *filter_type;
810
811         if (!subprocess_map_initialized) {
812                 subprocess_map_initialized = 1;
813                 hashmap_init(&subprocess_map, cmd2process_cmp, NULL, 0);
814                 entry = NULL;
815         } else {
816                 entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
817         }
818
819         fflush(NULL);
820
821         if (!entry) {
822                 entry = xmalloc(sizeof(*entry));
823                 entry->supported_capabilities = 0;
824
825                 if (subprocess_start(&subprocess_map, &entry->subprocess, cmd, start_multi_file_filter_fn)) {
826                         free(entry);
827                         return 0;
828                 }
829         }
830         process = &entry->subprocess.process;
831
832         if (!(entry->supported_capabilities & wanted_capability))
833                 return 0;
834
835         if (wanted_capability & CAP_CLEAN)
836                 filter_type = "clean";
837         else if (wanted_capability & CAP_SMUDGE)
838                 filter_type = "smudge";
839         else
840                 die(_("unexpected filter type"));
841
842         sigchain_push(SIGPIPE, SIG_IGN);
843
844         assert(strlen(filter_type) < LARGE_PACKET_DATA_MAX - strlen("command=\n"));
845         err = packet_write_fmt_gently(process->in, "command=%s\n", filter_type);
846         if (err)
847                 goto done;
848
849         err = strlen(path) > LARGE_PACKET_DATA_MAX - strlen("pathname=\n");
850         if (err) {
851                 error(_("path name too long for external filter"));
852                 goto done;
853         }
854
855         err = packet_write_fmt_gently(process->in, "pathname=%s\n", path);
856         if (err)
857                 goto done;
858
859         if (meta && meta->refname) {
860                 err = packet_write_fmt_gently(process->in, "ref=%s\n", meta->refname);
861                 if (err)
862                         goto done;
863         }
864
865         if (meta && !is_null_oid(&meta->treeish)) {
866                 err = packet_write_fmt_gently(process->in, "treeish=%s\n", oid_to_hex(&meta->treeish));
867                 if (err)
868                         goto done;
869         }
870
871         if (meta && !is_null_oid(&meta->blob)) {
872                 err = packet_write_fmt_gently(process->in, "blob=%s\n", oid_to_hex(&meta->blob));
873                 if (err)
874                         goto done;
875         }
876
877         if ((entry->supported_capabilities & CAP_DELAY) &&
878             dco && dco->state == CE_CAN_DELAY) {
879                 can_delay = 1;
880                 err = packet_write_fmt_gently(process->in, "can-delay=1\n");
881                 if (err)
882                         goto done;
883         }
884
885         err = packet_flush_gently(process->in);
886         if (err)
887                 goto done;
888
889         if (fd >= 0)
890                 err = write_packetized_from_fd(fd, process->in);
891         else
892                 err = write_packetized_from_buf(src, len, process->in);
893         if (err)
894                 goto done;
895
896         err = subprocess_read_status(process->out, &filter_status);
897         if (err)
898                 goto done;
899
900         if (can_delay && !strcmp(filter_status.buf, "delayed")) {
901                 string_list_insert(&dco->filters, cmd);
902                 string_list_insert(&dco->paths, path);
903         } else {
904                 /* The filter got the blob and wants to send us a response. */
905                 err = strcmp(filter_status.buf, "success");
906                 if (err)
907                         goto done;
908
909                 err = read_packetized_to_strbuf(process->out, &nbuf) < 0;
910                 if (err)
911                         goto done;
912
913                 err = subprocess_read_status(process->out, &filter_status);
914                 if (err)
915                         goto done;
916
917                 err = strcmp(filter_status.buf, "success");
918         }
919
920 done:
921         sigchain_pop(SIGPIPE);
922
923         if (err)
924                 handle_filter_error(&filter_status, entry, wanted_capability);
925         else
926                 strbuf_swap(dst, &nbuf);
927         strbuf_release(&nbuf);
928         return !err;
929 }
930
931
932 int async_query_available_blobs(const char *cmd, struct string_list *available_paths)
933 {
934         int err;
935         char *line;
936         struct cmd2process *entry;
937         struct child_process *process;
938         struct strbuf filter_status = STRBUF_INIT;
939
940         assert(subprocess_map_initialized);
941         entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
942         if (!entry) {
943                 error(_("external filter '%s' is not available anymore although "
944                         "not all paths have been filtered"), cmd);
945                 return 0;
946         }
947         process = &entry->subprocess.process;
948         sigchain_push(SIGPIPE, SIG_IGN);
949
950         err = packet_write_fmt_gently(
951                 process->in, "command=list_available_blobs\n");
952         if (err)
953                 goto done;
954
955         err = packet_flush_gently(process->in);
956         if (err)
957                 goto done;
958
959         while ((line = packet_read_line(process->out, NULL))) {
960                 const char *path;
961                 if (skip_prefix(line, "pathname=", &path))
962                         string_list_insert(available_paths, xstrdup(path));
963                 else
964                         ; /* ignore unknown keys */
965         }
966
967         err = subprocess_read_status(process->out, &filter_status);
968         if (err)
969                 goto done;
970
971         err = strcmp(filter_status.buf, "success");
972
973 done:
974         sigchain_pop(SIGPIPE);
975
976         if (err)
977                 handle_filter_error(&filter_status, entry, 0);
978         return !err;
979 }
980
981 static struct convert_driver {
982         const char *name;
983         struct convert_driver *next;
984         const char *smudge;
985         const char *clean;
986         const char *process;
987         int required;
988 } *user_convert, **user_convert_tail;
989
990 static int apply_filter(const char *path, const char *src, size_t len,
991                         int fd, struct strbuf *dst, struct convert_driver *drv,
992                         const unsigned int wanted_capability,
993                         const struct checkout_metadata *meta,
994                         struct delayed_checkout *dco)
995 {
996         const char *cmd = NULL;
997
998         if (!drv)
999                 return 0;
1000
1001         if (!dst)
1002                 return 1;
1003
1004         if ((wanted_capability & CAP_CLEAN) && !drv->process && drv->clean)
1005                 cmd = drv->clean;
1006         else if ((wanted_capability & CAP_SMUDGE) && !drv->process && drv->smudge)
1007                 cmd = drv->smudge;
1008
1009         if (cmd && *cmd)
1010                 return apply_single_file_filter(path, src, len, fd, dst, cmd);
1011         else if (drv->process && *drv->process)
1012                 return apply_multi_file_filter(path, src, len, fd, dst,
1013                         drv->process, wanted_capability, meta, dco);
1014
1015         return 0;
1016 }
1017
1018 static int read_convert_config(const char *var, const char *value, void *cb)
1019 {
1020         const char *key, *name;
1021         size_t namelen;
1022         struct convert_driver *drv;
1023
1024         /*
1025          * External conversion drivers are configured using
1026          * "filter.<name>.variable".
1027          */
1028         if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
1029                 return 0;
1030         for (drv = user_convert; drv; drv = drv->next)
1031                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
1032                         break;
1033         if (!drv) {
1034                 drv = xcalloc(1, sizeof(struct convert_driver));
1035                 drv->name = xmemdupz(name, namelen);
1036                 *user_convert_tail = drv;
1037                 user_convert_tail = &(drv->next);
1038         }
1039
1040         /*
1041          * filter.<name>.smudge and filter.<name>.clean specifies
1042          * the command line:
1043          *
1044          *      command-line
1045          *
1046          * The command-line will not be interpolated in any way.
1047          */
1048
1049         if (!strcmp("smudge", key))
1050                 return git_config_string(&drv->smudge, var, value);
1051
1052         if (!strcmp("clean", key))
1053                 return git_config_string(&drv->clean, var, value);
1054
1055         if (!strcmp("process", key))
1056                 return git_config_string(&drv->process, var, value);
1057
1058         if (!strcmp("required", key)) {
1059                 drv->required = git_config_bool(var, value);
1060                 return 0;
1061         }
1062
1063         return 0;
1064 }
1065
1066 static int count_ident(const char *cp, unsigned long size)
1067 {
1068         /*
1069          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
1070          */
1071         int cnt = 0;
1072         char ch;
1073
1074         while (size) {
1075                 ch = *cp++;
1076                 size--;
1077                 if (ch != '$')
1078                         continue;
1079                 if (size < 3)
1080                         break;
1081                 if (memcmp("Id", cp, 2))
1082                         continue;
1083                 ch = cp[2];
1084                 cp += 3;
1085                 size -= 3;
1086                 if (ch == '$')
1087                         cnt++; /* $Id$ */
1088                 if (ch != ':')
1089                         continue;
1090
1091                 /*
1092                  * "$Id: ... "; scan up to the closing dollar sign and discard.
1093                  */
1094                 while (size) {
1095                         ch = *cp++;
1096                         size--;
1097                         if (ch == '$') {
1098                                 cnt++;
1099                                 break;
1100                         }
1101                         if (ch == '\n')
1102                                 break;
1103                 }
1104         }
1105         return cnt;
1106 }
1107
1108 static int ident_to_git(const char *src, size_t len,
1109                         struct strbuf *buf, int ident)
1110 {
1111         char *dst, *dollar;
1112
1113         if (!ident || (src && !count_ident(src, len)))
1114                 return 0;
1115
1116         if (!buf)
1117                 return 1;
1118
1119         /* only grow if not in place */
1120         if (strbuf_avail(buf) + buf->len < len)
1121                 strbuf_grow(buf, len - buf->len);
1122         dst = buf->buf;
1123         for (;;) {
1124                 dollar = memchr(src, '$', len);
1125                 if (!dollar)
1126                         break;
1127                 memmove(dst, src, dollar + 1 - src);
1128                 dst += dollar + 1 - src;
1129                 len -= dollar + 1 - src;
1130                 src  = dollar + 1;
1131
1132                 if (len > 3 && !memcmp(src, "Id:", 3)) {
1133                         dollar = memchr(src + 3, '$', len - 3);
1134                         if (!dollar)
1135                                 break;
1136                         if (memchr(src + 3, '\n', dollar - src - 3)) {
1137                                 /* Line break before the next dollar. */
1138                                 continue;
1139                         }
1140
1141                         memcpy(dst, "Id$", 3);
1142                         dst += 3;
1143                         len -= dollar + 1 - src;
1144                         src  = dollar + 1;
1145                 }
1146         }
1147         memmove(dst, src, len);
1148         strbuf_setlen(buf, dst + len - buf->buf);
1149         return 1;
1150 }
1151
1152 static int ident_to_worktree(const char *src, size_t len,
1153                              struct strbuf *buf, int ident)
1154 {
1155         struct object_id oid;
1156         char *to_free = NULL, *dollar, *spc;
1157         int cnt;
1158
1159         if (!ident)
1160                 return 0;
1161
1162         cnt = count_ident(src, len);
1163         if (!cnt)
1164                 return 0;
1165
1166         /* are we "faking" in place editing ? */
1167         if (src == buf->buf)
1168                 to_free = strbuf_detach(buf, NULL);
1169         hash_object_file(the_hash_algo, src, len, "blob", &oid);
1170
1171         strbuf_grow(buf, len + cnt * (the_hash_algo->hexsz + 3));
1172         for (;;) {
1173                 /* step 1: run to the next '$' */
1174                 dollar = memchr(src, '$', len);
1175                 if (!dollar)
1176                         break;
1177                 strbuf_add(buf, src, dollar + 1 - src);
1178                 len -= dollar + 1 - src;
1179                 src  = dollar + 1;
1180
1181                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
1182                 if (len < 3 || memcmp("Id", src, 2))
1183                         continue;
1184
1185                 /* step 3: skip over Id$ or Id:xxxxx$ */
1186                 if (src[2] == '$') {
1187                         src += 3;
1188                         len -= 3;
1189                 } else if (src[2] == ':') {
1190                         /*
1191                          * It's possible that an expanded Id has crept its way into the
1192                          * repository, we cope with that by stripping the expansion out.
1193                          * This is probably not a good idea, since it will cause changes
1194                          * on checkout, which won't go away by stash, but let's keep it
1195                          * for git-style ids.
1196                          */
1197                         dollar = memchr(src + 3, '$', len - 3);
1198                         if (!dollar) {
1199                                 /* incomplete keyword, no more '$', so just quit the loop */
1200                                 break;
1201                         }
1202
1203                         if (memchr(src + 3, '\n', dollar - src - 3)) {
1204                                 /* Line break before the next dollar. */
1205                                 continue;
1206                         }
1207
1208                         spc = memchr(src + 4, ' ', dollar - src - 4);
1209                         if (spc && spc < dollar-1) {
1210                                 /* There are spaces in unexpected places.
1211                                  * This is probably an id from some other
1212                                  * versioning system. Keep it for now.
1213                                  */
1214                                 continue;
1215                         }
1216
1217                         len -= dollar + 1 - src;
1218                         src  = dollar + 1;
1219                 } else {
1220                         /* it wasn't a "Id$" or "Id:xxxx$" */
1221                         continue;
1222                 }
1223
1224                 /* step 4: substitute */
1225                 strbuf_addstr(buf, "Id: ");
1226                 strbuf_addstr(buf, oid_to_hex(&oid));
1227                 strbuf_addstr(buf, " $");
1228         }
1229         strbuf_add(buf, src, len);
1230
1231         free(to_free);
1232         return 1;
1233 }
1234
1235 static const char *git_path_check_encoding(struct attr_check_item *check)
1236 {
1237         const char *value = check->value;
1238
1239         if (ATTR_UNSET(value) || !strlen(value))
1240                 return NULL;
1241
1242         if (ATTR_TRUE(value) || ATTR_FALSE(value)) {
1243                 die(_("true/false are no valid working-tree-encodings"));
1244         }
1245
1246         /* Don't encode to the default encoding */
1247         if (same_encoding(value, default_encoding))
1248                 return NULL;
1249
1250         return value;
1251 }
1252
1253 static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
1254 {
1255         const char *value = check->value;
1256
1257         if (ATTR_TRUE(value))
1258                 return CRLF_TEXT;
1259         else if (ATTR_FALSE(value))
1260                 return CRLF_BINARY;
1261         else if (ATTR_UNSET(value))
1262                 ;
1263         else if (!strcmp(value, "input"))
1264                 return CRLF_TEXT_INPUT;
1265         else if (!strcmp(value, "auto"))
1266                 return CRLF_AUTO;
1267         return CRLF_UNDEFINED;
1268 }
1269
1270 static enum eol git_path_check_eol(struct attr_check_item *check)
1271 {
1272         const char *value = check->value;
1273
1274         if (ATTR_UNSET(value))
1275                 ;
1276         else if (!strcmp(value, "lf"))
1277                 return EOL_LF;
1278         else if (!strcmp(value, "crlf"))
1279                 return EOL_CRLF;
1280         return EOL_UNSET;
1281 }
1282
1283 static struct convert_driver *git_path_check_convert(struct attr_check_item *check)
1284 {
1285         const char *value = check->value;
1286         struct convert_driver *drv;
1287
1288         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1289                 return NULL;
1290         for (drv = user_convert; drv; drv = drv->next)
1291                 if (!strcmp(value, drv->name))
1292                         return drv;
1293         return NULL;
1294 }
1295
1296 static int git_path_check_ident(struct attr_check_item *check)
1297 {
1298         const char *value = check->value;
1299
1300         return !!ATTR_TRUE(value);
1301 }
1302
1303 struct conv_attrs {
1304         struct convert_driver *drv;
1305         enum crlf_action attr_action; /* What attr says */
1306         enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
1307         int ident;
1308         const char *working_tree_encoding; /* Supported encoding or default encoding if NULL */
1309 };
1310
1311 static struct attr_check *check;
1312
1313 static void convert_attrs(const struct index_state *istate,
1314                           struct conv_attrs *ca, const char *path)
1315 {
1316         struct attr_check_item *ccheck = NULL;
1317
1318         if (!check) {
1319                 check = attr_check_initl("crlf", "ident", "filter",
1320                                          "eol", "text", "working-tree-encoding",
1321                                          NULL);
1322                 user_convert_tail = &user_convert;
1323                 git_config(read_convert_config, NULL);
1324         }
1325
1326         git_check_attr(istate, path, check);
1327         ccheck = check->items;
1328         ca->crlf_action = git_path_check_crlf(ccheck + 4);
1329         if (ca->crlf_action == CRLF_UNDEFINED)
1330                 ca->crlf_action = git_path_check_crlf(ccheck + 0);
1331         ca->ident = git_path_check_ident(ccheck + 1);
1332         ca->drv = git_path_check_convert(ccheck + 2);
1333         if (ca->crlf_action != CRLF_BINARY) {
1334                 enum eol eol_attr = git_path_check_eol(ccheck + 3);
1335                 if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
1336                         ca->crlf_action = CRLF_AUTO_INPUT;
1337                 else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
1338                         ca->crlf_action = CRLF_AUTO_CRLF;
1339                 else if (eol_attr == EOL_LF)
1340                         ca->crlf_action = CRLF_TEXT_INPUT;
1341                 else if (eol_attr == EOL_CRLF)
1342                         ca->crlf_action = CRLF_TEXT_CRLF;
1343         }
1344         ca->working_tree_encoding = git_path_check_encoding(ccheck + 5);
1345
1346         /* Save attr and make a decision for action */
1347         ca->attr_action = ca->crlf_action;
1348         if (ca->crlf_action == CRLF_TEXT)
1349                 ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
1350         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
1351                 ca->crlf_action = CRLF_BINARY;
1352         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
1353                 ca->crlf_action = CRLF_AUTO_CRLF;
1354         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
1355                 ca->crlf_action = CRLF_AUTO_INPUT;
1356 }
1357
1358 void reset_parsed_attributes(void)
1359 {
1360         struct convert_driver *drv, *next;
1361
1362         attr_check_free(check);
1363         check = NULL;
1364         reset_merge_attributes();
1365
1366         for (drv = user_convert; drv; drv = next) {
1367                 next = drv->next;
1368                 free((void *)drv->name);
1369                 free(drv);
1370         }
1371         user_convert = NULL;
1372         user_convert_tail = NULL;
1373 }
1374
1375 int would_convert_to_git_filter_fd(const struct index_state *istate, const char *path)
1376 {
1377         struct conv_attrs ca;
1378
1379         convert_attrs(istate, &ca, path);
1380         if (!ca.drv)
1381                 return 0;
1382
1383         /*
1384          * Apply a filter to an fd only if the filter is required to succeed.
1385          * We must die if the filter fails, because the original data before
1386          * filtering is not available.
1387          */
1388         if (!ca.drv->required)
1389                 return 0;
1390
1391         return apply_filter(path, NULL, 0, -1, NULL, ca.drv, CAP_CLEAN, NULL, NULL);
1392 }
1393
1394 const char *get_convert_attr_ascii(const struct index_state *istate, const char *path)
1395 {
1396         struct conv_attrs ca;
1397
1398         convert_attrs(istate, &ca, path);
1399         switch (ca.attr_action) {
1400         case CRLF_UNDEFINED:
1401                 return "";
1402         case CRLF_BINARY:
1403                 return "-text";
1404         case CRLF_TEXT:
1405                 return "text";
1406         case CRLF_TEXT_INPUT:
1407                 return "text eol=lf";
1408         case CRLF_TEXT_CRLF:
1409                 return "text eol=crlf";
1410         case CRLF_AUTO:
1411                 return "text=auto";
1412         case CRLF_AUTO_CRLF:
1413                 return "text=auto eol=crlf";
1414         case CRLF_AUTO_INPUT:
1415                 return "text=auto eol=lf";
1416         }
1417         return "";
1418 }
1419
1420 int convert_to_git(const struct index_state *istate,
1421                    const char *path, const char *src, size_t len,
1422                    struct strbuf *dst, int conv_flags)
1423 {
1424         int ret = 0;
1425         struct conv_attrs ca;
1426
1427         convert_attrs(istate, &ca, path);
1428
1429         ret |= apply_filter(path, src, len, -1, dst, ca.drv, CAP_CLEAN, NULL, NULL);
1430         if (!ret && ca.drv && ca.drv->required)
1431                 die(_("%s: clean filter '%s' failed"), path, ca.drv->name);
1432
1433         if (ret && dst) {
1434                 src = dst->buf;
1435                 len = dst->len;
1436         }
1437
1438         ret |= encode_to_git(path, src, len, dst, ca.working_tree_encoding, conv_flags);
1439         if (ret && dst) {
1440                 src = dst->buf;
1441                 len = dst->len;
1442         }
1443
1444         if (!(conv_flags & CONV_EOL_KEEP_CRLF)) {
1445                 ret |= crlf_to_git(istate, path, src, len, dst, ca.crlf_action, conv_flags);
1446                 if (ret && dst) {
1447                         src = dst->buf;
1448                         len = dst->len;
1449                 }
1450         }
1451         return ret | ident_to_git(src, len, dst, ca.ident);
1452 }
1453
1454 void convert_to_git_filter_fd(const struct index_state *istate,
1455                               const char *path, int fd, struct strbuf *dst,
1456                               int conv_flags)
1457 {
1458         struct conv_attrs ca;
1459         convert_attrs(istate, &ca, path);
1460
1461         assert(ca.drv);
1462         assert(ca.drv->clean || ca.drv->process);
1463
1464         if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN, NULL, NULL))
1465                 die(_("%s: clean filter '%s' failed"), path, ca.drv->name);
1466
1467         encode_to_git(path, dst->buf, dst->len, dst, ca.working_tree_encoding, conv_flags);
1468         crlf_to_git(istate, path, dst->buf, dst->len, dst, ca.crlf_action, conv_flags);
1469         ident_to_git(dst->buf, dst->len, dst, ca.ident);
1470 }
1471
1472 static int convert_to_working_tree_internal(const struct index_state *istate,
1473                                             const char *path, const char *src,
1474                                             size_t len, struct strbuf *dst,
1475                                             int normalizing,
1476                                             const struct checkout_metadata *meta,
1477                                             struct delayed_checkout *dco)
1478 {
1479         int ret = 0, ret_filter = 0;
1480         struct conv_attrs ca;
1481
1482         convert_attrs(istate, &ca, path);
1483
1484         ret |= ident_to_worktree(src, len, dst, ca.ident);
1485         if (ret) {
1486                 src = dst->buf;
1487                 len = dst->len;
1488         }
1489         /*
1490          * CRLF conversion can be skipped if normalizing, unless there
1491          * is a smudge or process filter (even if the process filter doesn't
1492          * support smudge).  The filters might expect CRLFs.
1493          */
1494         if ((ca.drv && (ca.drv->smudge || ca.drv->process)) || !normalizing) {
1495                 ret |= crlf_to_worktree(src, len, dst, ca.crlf_action);
1496                 if (ret) {
1497                         src = dst->buf;
1498                         len = dst->len;
1499                 }
1500         }
1501
1502         ret |= encode_to_worktree(path, src, len, dst, ca.working_tree_encoding);
1503         if (ret) {
1504                 src = dst->buf;
1505                 len = dst->len;
1506         }
1507
1508         ret_filter = apply_filter(
1509                 path, src, len, -1, dst, ca.drv, CAP_SMUDGE, meta, dco);
1510         if (!ret_filter && ca.drv && ca.drv->required)
1511                 die(_("%s: smudge filter %s failed"), path, ca.drv->name);
1512
1513         return ret | ret_filter;
1514 }
1515
1516 int async_convert_to_working_tree(const struct index_state *istate,
1517                                   const char *path, const char *src,
1518                                   size_t len, struct strbuf *dst,
1519                                   const struct checkout_metadata *meta,
1520                                   void *dco)
1521 {
1522         return convert_to_working_tree_internal(istate, path, src, len, dst, 0, meta, dco);
1523 }
1524
1525 int convert_to_working_tree(const struct index_state *istate,
1526                             const char *path, const char *src,
1527                             size_t len, struct strbuf *dst,
1528                             const struct checkout_metadata *meta)
1529 {
1530         return convert_to_working_tree_internal(istate, path, src, len, dst, 0, meta, NULL);
1531 }
1532
1533 int renormalize_buffer(const struct index_state *istate, const char *path,
1534                        const char *src, size_t len, struct strbuf *dst)
1535 {
1536         int ret = convert_to_working_tree_internal(istate, path, src, len, dst, 1, NULL, NULL);
1537         if (ret) {
1538                 src = dst->buf;
1539                 len = dst->len;
1540         }
1541         return ret | convert_to_git(istate, path, src, len, dst, CONV_EOL_RENORMALIZE);
1542 }
1543
1544 /*****************************************************************
1545  *
1546  * Streaming conversion support
1547  *
1548  *****************************************************************/
1549
1550 typedef int (*filter_fn)(struct stream_filter *,
1551                          const char *input, size_t *isize_p,
1552                          char *output, size_t *osize_p);
1553 typedef void (*free_fn)(struct stream_filter *);
1554
1555 struct stream_filter_vtbl {
1556         filter_fn filter;
1557         free_fn free;
1558 };
1559
1560 struct stream_filter {
1561         struct stream_filter_vtbl *vtbl;
1562 };
1563
1564 static int null_filter_fn(struct stream_filter *filter,
1565                           const char *input, size_t *isize_p,
1566                           char *output, size_t *osize_p)
1567 {
1568         size_t count;
1569
1570         if (!input)
1571                 return 0; /* we do not keep any states */
1572         count = *isize_p;
1573         if (*osize_p < count)
1574                 count = *osize_p;
1575         if (count) {
1576                 memmove(output, input, count);
1577                 *isize_p -= count;
1578                 *osize_p -= count;
1579         }
1580         return 0;
1581 }
1582
1583 static void null_free_fn(struct stream_filter *filter)
1584 {
1585         ; /* nothing -- null instances are shared */
1586 }
1587
1588 static struct stream_filter_vtbl null_vtbl = {
1589         null_filter_fn,
1590         null_free_fn,
1591 };
1592
1593 static struct stream_filter null_filter_singleton = {
1594         &null_vtbl,
1595 };
1596
1597 int is_null_stream_filter(struct stream_filter *filter)
1598 {
1599         return filter == &null_filter_singleton;
1600 }
1601
1602
1603 /*
1604  * LF-to-CRLF filter
1605  */
1606
1607 struct lf_to_crlf_filter {
1608         struct stream_filter filter;
1609         unsigned has_held:1;
1610         char held;
1611 };
1612
1613 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1614                                 const char *input, size_t *isize_p,
1615                                 char *output, size_t *osize_p)
1616 {
1617         size_t count, o = 0;
1618         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1619
1620         /*
1621          * We may be holding onto the CR to see if it is followed by a
1622          * LF, in which case we would need to go to the main loop.
1623          * Otherwise, just emit it to the output stream.
1624          */
1625         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1626                 output[o++] = lf_to_crlf->held;
1627                 lf_to_crlf->has_held = 0;
1628         }
1629
1630         /* We are told to drain */
1631         if (!input) {
1632                 *osize_p -= o;
1633                 return 0;
1634         }
1635
1636         count = *isize_p;
1637         if (count || lf_to_crlf->has_held) {
1638                 size_t i;
1639                 int was_cr = 0;
1640
1641                 if (lf_to_crlf->has_held) {
1642                         was_cr = 1;
1643                         lf_to_crlf->has_held = 0;
1644                 }
1645
1646                 for (i = 0; o < *osize_p && i < count; i++) {
1647                         char ch = input[i];
1648
1649                         if (ch == '\n') {
1650                                 output[o++] = '\r';
1651                         } else if (was_cr) {
1652                                 /*
1653                                  * Previous round saw CR and it is not followed
1654                                  * by a LF; emit the CR before processing the
1655                                  * current character.
1656                                  */
1657                                 output[o++] = '\r';
1658                         }
1659
1660                         /*
1661                          * We may have consumed the last output slot,
1662                          * in which case we need to break out of this
1663                          * loop; hold the current character before
1664                          * returning.
1665                          */
1666                         if (*osize_p <= o) {
1667                                 lf_to_crlf->has_held = 1;
1668                                 lf_to_crlf->held = ch;
1669                                 continue; /* break but increment i */
1670                         }
1671
1672                         if (ch == '\r') {
1673                                 was_cr = 1;
1674                                 continue;
1675                         }
1676
1677                         was_cr = 0;
1678                         output[o++] = ch;
1679                 }
1680
1681                 *osize_p -= o;
1682                 *isize_p -= i;
1683
1684                 if (!lf_to_crlf->has_held && was_cr) {
1685                         lf_to_crlf->has_held = 1;
1686                         lf_to_crlf->held = '\r';
1687                 }
1688         }
1689         return 0;
1690 }
1691
1692 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1693 {
1694         free(filter);
1695 }
1696
1697 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1698         lf_to_crlf_filter_fn,
1699         lf_to_crlf_free_fn,
1700 };
1701
1702 static struct stream_filter *lf_to_crlf_filter(void)
1703 {
1704         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1705
1706         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1707         return (struct stream_filter *)lf_to_crlf;
1708 }
1709
1710 /*
1711  * Cascade filter
1712  */
1713 #define FILTER_BUFFER 1024
1714 struct cascade_filter {
1715         struct stream_filter filter;
1716         struct stream_filter *one;
1717         struct stream_filter *two;
1718         char buf[FILTER_BUFFER];
1719         int end, ptr;
1720 };
1721
1722 static int cascade_filter_fn(struct stream_filter *filter,
1723                              const char *input, size_t *isize_p,
1724                              char *output, size_t *osize_p)
1725 {
1726         struct cascade_filter *cas = (struct cascade_filter *) filter;
1727         size_t filled = 0;
1728         size_t sz = *osize_p;
1729         size_t to_feed, remaining;
1730
1731         /*
1732          * input -- (one) --> buf -- (two) --> output
1733          */
1734         while (filled < sz) {
1735                 remaining = sz - filled;
1736
1737                 /* do we already have something to feed two with? */
1738                 if (cas->ptr < cas->end) {
1739                         to_feed = cas->end - cas->ptr;
1740                         if (stream_filter(cas->two,
1741                                           cas->buf + cas->ptr, &to_feed,
1742                                           output + filled, &remaining))
1743                                 return -1;
1744                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1745                         filled = sz - remaining;
1746                         continue;
1747                 }
1748
1749                 /* feed one from upstream and have it emit into our buffer */
1750                 to_feed = input ? *isize_p : 0;
1751                 if (input && !to_feed)
1752                         break;
1753                 remaining = sizeof(cas->buf);
1754                 if (stream_filter(cas->one,
1755                                   input, &to_feed,
1756                                   cas->buf, &remaining))
1757                         return -1;
1758                 cas->end = sizeof(cas->buf) - remaining;
1759                 cas->ptr = 0;
1760                 if (input) {
1761                         size_t fed = *isize_p - to_feed;
1762                         *isize_p -= fed;
1763                         input += fed;
1764                 }
1765
1766                 /* do we know that we drained one completely? */
1767                 if (input || cas->end)
1768                         continue;
1769
1770                 /* tell two to drain; we have nothing more to give it */
1771                 to_feed = 0;
1772                 remaining = sz - filled;
1773                 if (stream_filter(cas->two,
1774                                   NULL, &to_feed,
1775                                   output + filled, &remaining))
1776                         return -1;
1777                 if (remaining == (sz - filled))
1778                         break; /* completely drained two */
1779                 filled = sz - remaining;
1780         }
1781         *osize_p -= filled;
1782         return 0;
1783 }
1784
1785 static void cascade_free_fn(struct stream_filter *filter)
1786 {
1787         struct cascade_filter *cas = (struct cascade_filter *)filter;
1788         free_stream_filter(cas->one);
1789         free_stream_filter(cas->two);
1790         free(filter);
1791 }
1792
1793 static struct stream_filter_vtbl cascade_vtbl = {
1794         cascade_filter_fn,
1795         cascade_free_fn,
1796 };
1797
1798 static struct stream_filter *cascade_filter(struct stream_filter *one,
1799                                             struct stream_filter *two)
1800 {
1801         struct cascade_filter *cascade;
1802
1803         if (!one || is_null_stream_filter(one))
1804                 return two;
1805         if (!two || is_null_stream_filter(two))
1806                 return one;
1807
1808         cascade = xmalloc(sizeof(*cascade));
1809         cascade->one = one;
1810         cascade->two = two;
1811         cascade->end = cascade->ptr = 0;
1812         cascade->filter.vtbl = &cascade_vtbl;
1813         return (struct stream_filter *)cascade;
1814 }
1815
1816 /*
1817  * ident filter
1818  */
1819 #define IDENT_DRAINING (-1)
1820 #define IDENT_SKIPPING (-2)
1821 struct ident_filter {
1822         struct stream_filter filter;
1823         struct strbuf left;
1824         int state;
1825         char ident[GIT_MAX_HEXSZ + 5]; /* ": x40 $" */
1826 };
1827
1828 static int is_foreign_ident(const char *str)
1829 {
1830         int i;
1831
1832         if (!skip_prefix(str, "$Id: ", &str))
1833                 return 0;
1834         for (i = 0; str[i]; i++) {
1835                 if (isspace(str[i]) && str[i+1] != '$')
1836                         return 1;
1837         }
1838         return 0;
1839 }
1840
1841 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1842 {
1843         size_t to_drain = ident->left.len;
1844
1845         if (*osize_p < to_drain)
1846                 to_drain = *osize_p;
1847         if (to_drain) {
1848                 memcpy(*output_p, ident->left.buf, to_drain);
1849                 strbuf_remove(&ident->left, 0, to_drain);
1850                 *output_p += to_drain;
1851                 *osize_p -= to_drain;
1852         }
1853         if (!ident->left.len)
1854                 ident->state = 0;
1855 }
1856
1857 static int ident_filter_fn(struct stream_filter *filter,
1858                            const char *input, size_t *isize_p,
1859                            char *output, size_t *osize_p)
1860 {
1861         struct ident_filter *ident = (struct ident_filter *)filter;
1862         static const char head[] = "$Id";
1863
1864         if (!input) {
1865                 /* drain upon eof */
1866                 switch (ident->state) {
1867                 default:
1868                         strbuf_add(&ident->left, head, ident->state);
1869                         /* fallthrough */
1870                 case IDENT_SKIPPING:
1871                         /* fallthrough */
1872                 case IDENT_DRAINING:
1873                         ident_drain(ident, &output, osize_p);
1874                 }
1875                 return 0;
1876         }
1877
1878         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1879                 int ch;
1880
1881                 if (ident->state == IDENT_DRAINING) {
1882                         ident_drain(ident, &output, osize_p);
1883                         if (!*osize_p)
1884                                 break;
1885                         continue;
1886                 }
1887
1888                 ch = *(input++);
1889                 (*isize_p)--;
1890
1891                 if (ident->state == IDENT_SKIPPING) {
1892                         /*
1893                          * Skipping until '$' or LF, but keeping them
1894                          * in case it is a foreign ident.
1895                          */
1896                         strbuf_addch(&ident->left, ch);
1897                         if (ch != '\n' && ch != '$')
1898                                 continue;
1899                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1900                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1901                                 strbuf_addstr(&ident->left, ident->ident);
1902                         }
1903                         ident->state = IDENT_DRAINING;
1904                         continue;
1905                 }
1906
1907                 if (ident->state < sizeof(head) &&
1908                     head[ident->state] == ch) {
1909                         ident->state++;
1910                         continue;
1911                 }
1912
1913                 if (ident->state)
1914                         strbuf_add(&ident->left, head, ident->state);
1915                 if (ident->state == sizeof(head) - 1) {
1916                         if (ch != ':' && ch != '$') {
1917                                 strbuf_addch(&ident->left, ch);
1918                                 ident->state = 0;
1919                                 continue;
1920                         }
1921
1922                         if (ch == ':') {
1923                                 strbuf_addch(&ident->left, ch);
1924                                 ident->state = IDENT_SKIPPING;
1925                         } else {
1926                                 strbuf_addstr(&ident->left, ident->ident);
1927                                 ident->state = IDENT_DRAINING;
1928                         }
1929                         continue;
1930                 }
1931
1932                 strbuf_addch(&ident->left, ch);
1933                 ident->state = IDENT_DRAINING;
1934         }
1935         return 0;
1936 }
1937
1938 static void ident_free_fn(struct stream_filter *filter)
1939 {
1940         struct ident_filter *ident = (struct ident_filter *)filter;
1941         strbuf_release(&ident->left);
1942         free(filter);
1943 }
1944
1945 static struct stream_filter_vtbl ident_vtbl = {
1946         ident_filter_fn,
1947         ident_free_fn,
1948 };
1949
1950 static struct stream_filter *ident_filter(const struct object_id *oid)
1951 {
1952         struct ident_filter *ident = xmalloc(sizeof(*ident));
1953
1954         xsnprintf(ident->ident, sizeof(ident->ident),
1955                   ": %s $", oid_to_hex(oid));
1956         strbuf_init(&ident->left, 0);
1957         ident->filter.vtbl = &ident_vtbl;
1958         ident->state = 0;
1959         return (struct stream_filter *)ident;
1960 }
1961
1962 /*
1963  * Return an appropriately constructed filter for the path, or NULL if
1964  * the contents cannot be filtered without reading the whole thing
1965  * in-core.
1966  *
1967  * Note that you would be crazy to set CRLF, smudge/clean or ident to a
1968  * large binary blob you would want us not to slurp into the memory!
1969  */
1970 struct stream_filter *get_stream_filter(const struct index_state *istate,
1971                                         const char *path,
1972                                         const struct object_id *oid)
1973 {
1974         struct conv_attrs ca;
1975         struct stream_filter *filter = NULL;
1976
1977         convert_attrs(istate, &ca, path);
1978         if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
1979                 return NULL;
1980
1981         if (ca.working_tree_encoding)
1982                 return NULL;
1983
1984         if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1985                 return NULL;
1986
1987         if (ca.ident)
1988                 filter = ident_filter(oid);
1989
1990         if (output_eol(ca.crlf_action) == EOL_CRLF)
1991                 filter = cascade_filter(filter, lf_to_crlf_filter());
1992         else
1993                 filter = cascade_filter(filter, &null_filter_singleton);
1994
1995         return filter;
1996 }
1997
1998 void free_stream_filter(struct stream_filter *filter)
1999 {
2000         filter->vtbl->free(filter);
2001 }
2002
2003 int stream_filter(struct stream_filter *filter,
2004                   const char *input, size_t *isize_p,
2005                   char *output, size_t *osize_p)
2006 {
2007         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
2008 }
2009
2010 void init_checkout_metadata(struct checkout_metadata *meta, const char *refname,
2011                             const struct object_id *treeish,
2012                             const struct object_id *blob)
2013 {
2014         memset(meta, 0, sizeof(*meta));
2015         if (refname)
2016                 meta->refname = refname;
2017         if (treeish)
2018                 oidcpy(&meta->treeish, treeish);
2019         if (blob)
2020                 oidcpy(&meta->blob, blob);
2021 }
2022
2023 void clone_checkout_metadata(struct checkout_metadata *dst,
2024                              const struct checkout_metadata *src,
2025                              const struct object_id *blob)
2026 {
2027         memcpy(dst, src, sizeof(*dst));
2028         if (blob)
2029                 oidcpy(&dst->blob, blob);
2030 }