Merge branch 'nf/mergetool-prompt'
[git] / convert.c
1 #include "cache.h"
2 #include "attr.h"
3 #include "run-command.h"
4 #include "quote.h"
5 #include "sigchain.h"
6
7 /*
8  * convert.c - convert a file when checking it out and checking it in.
9  *
10  * This should use the pathname to decide on whether it wants to do some
11  * more interesting conversions (automatic gzip/unzip, general format
12  * conversions etc etc), but by default it just does automatic CRLF<->LF
13  * translation when the "text" attribute or "auto_crlf" option is set.
14  */
15
16 /* Stat bits: When BIN is set, the txt bits are unset */
17 #define CONVERT_STAT_BITS_TXT_LF    0x1
18 #define CONVERT_STAT_BITS_TXT_CRLF  0x2
19 #define CONVERT_STAT_BITS_BIN       0x4
20
21 enum crlf_action {
22         CRLF_UNDEFINED,
23         CRLF_BINARY,
24         CRLF_TEXT,
25         CRLF_TEXT_INPUT,
26         CRLF_TEXT_CRLF,
27         CRLF_AUTO,
28         CRLF_AUTO_INPUT,
29         CRLF_AUTO_CRLF
30 };
31
32 struct text_stat {
33         /* NUL, CR, LF and CRLF counts */
34         unsigned nul, lonecr, lonelf, crlf;
35
36         /* These are just approximations! */
37         unsigned printable, nonprintable;
38 };
39
40 static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
41 {
42         unsigned long i;
43
44         memset(stats, 0, sizeof(*stats));
45
46         for (i = 0; i < size; i++) {
47                 unsigned char c = buf[i];
48                 if (c == '\r') {
49                         if (i+1 < size && buf[i+1] == '\n') {
50                                 stats->crlf++;
51                                 i++;
52                         } else
53                                 stats->lonecr++;
54                         continue;
55                 }
56                 if (c == '\n') {
57                         stats->lonelf++;
58                         continue;
59                 }
60                 if (c == 127)
61                         /* DEL */
62                         stats->nonprintable++;
63                 else if (c < 32) {
64                         switch (c) {
65                                 /* BS, HT, ESC and FF */
66                         case '\b': case '\t': case '\033': case '\014':
67                                 stats->printable++;
68                                 break;
69                         case 0:
70                                 stats->nul++;
71                                 /* fall through */
72                         default:
73                                 stats->nonprintable++;
74                         }
75                 }
76                 else
77                         stats->printable++;
78         }
79
80         /* If file ends with EOF then don't count this EOF as non-printable. */
81         if (size >= 1 && buf[size-1] == '\032')
82                 stats->nonprintable--;
83 }
84
85 /*
86  * The same heuristics as diff.c::mmfile_is_binary()
87  * We treat files with bare CR as binary
88  */
89 static int convert_is_binary(unsigned long size, const struct text_stat *stats)
90 {
91         if (stats->lonecr)
92                 return 1;
93         if (stats->nul)
94                 return 1;
95         if ((stats->printable >> 7) < stats->nonprintable)
96                 return 1;
97         return 0;
98 }
99
100 static unsigned int gather_convert_stats(const char *data, unsigned long size)
101 {
102         struct text_stat stats;
103         int ret = 0;
104         if (!data || !size)
105                 return 0;
106         gather_stats(data, size, &stats);
107         if (convert_is_binary(size, &stats))
108                 ret |= CONVERT_STAT_BITS_BIN;
109         if (stats.crlf)
110                 ret |= CONVERT_STAT_BITS_TXT_CRLF;
111         if (stats.lonelf)
112                 ret |=  CONVERT_STAT_BITS_TXT_LF;
113
114         return ret;
115 }
116
117 static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
118 {
119         unsigned int convert_stats = gather_convert_stats(data, size);
120
121         if (convert_stats & CONVERT_STAT_BITS_BIN)
122                 return "-text";
123         switch (convert_stats) {
124         case CONVERT_STAT_BITS_TXT_LF:
125                 return "lf";
126         case CONVERT_STAT_BITS_TXT_CRLF:
127                 return "crlf";
128         case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
129                 return "mixed";
130         default:
131                 return "none";
132         }
133 }
134
135 const char *get_cached_convert_stats_ascii(const char *path)
136 {
137         const char *ret;
138         unsigned long sz;
139         void *data = read_blob_data_from_cache(path, &sz);
140         ret = gather_convert_stats_ascii(data, sz);
141         free(data);
142         return ret;
143 }
144
145 const char *get_wt_convert_stats_ascii(const char *path)
146 {
147         const char *ret = "";
148         struct strbuf sb = STRBUF_INIT;
149         if (strbuf_read_file(&sb, path, 0) >= 0)
150                 ret = gather_convert_stats_ascii(sb.buf, sb.len);
151         strbuf_release(&sb);
152         return ret;
153 }
154
155 static int text_eol_is_crlf(void)
156 {
157         if (auto_crlf == AUTO_CRLF_TRUE)
158                 return 1;
159         else if (auto_crlf == AUTO_CRLF_INPUT)
160                 return 0;
161         if (core_eol == EOL_CRLF)
162                 return 1;
163         if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
164                 return 1;
165         return 0;
166 }
167
168 static enum eol output_eol(enum crlf_action crlf_action)
169 {
170         switch (crlf_action) {
171         case CRLF_BINARY:
172                 return EOL_UNSET;
173         case CRLF_TEXT_CRLF:
174                 return EOL_CRLF;
175         case CRLF_TEXT_INPUT:
176                 return EOL_LF;
177         case CRLF_UNDEFINED:
178         case CRLF_AUTO_CRLF:
179         case CRLF_AUTO_INPUT:
180         case CRLF_TEXT:
181         case CRLF_AUTO:
182                 /* fall through */
183                 return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
184         }
185         warning("Illegal crlf_action %d\n", (int)crlf_action);
186         return core_eol;
187 }
188
189 static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
190                             struct text_stat *stats, enum safe_crlf checksafe)
191 {
192         if (!checksafe)
193                 return;
194
195         if (output_eol(crlf_action) == EOL_LF) {
196                 /*
197                  * CRLFs would not be restored by checkout:
198                  * check if we'd remove CRLFs
199                  */
200                 if (stats->crlf) {
201                         if (checksafe == SAFE_CRLF_WARN)
202                                 warning("CRLF will be replaced by LF in %s.\nThe file will have its original line endings in your working directory.", path);
203                         else /* i.e. SAFE_CRLF_FAIL */
204                                 die("CRLF would be replaced by LF in %s.", path);
205                 }
206         } else if (output_eol(crlf_action) == EOL_CRLF) {
207                 /*
208                  * CRLFs would be added by checkout:
209                  * check if we have "naked" LFs
210                  */
211                 if (stats->lonelf) {
212                         if (checksafe == SAFE_CRLF_WARN)
213                                 warning("LF will be replaced by CRLF in %s.\nThe file will have its original line endings in your working directory.", path);
214                         else /* i.e. SAFE_CRLF_FAIL */
215                                 die("LF would be replaced by CRLF in %s", path);
216                 }
217         }
218 }
219
220 static int has_cr_in_index(const char *path)
221 {
222         unsigned long sz;
223         void *data;
224         int has_cr;
225
226         data = read_blob_data_from_cache(path, &sz);
227         if (!data)
228                 return 0;
229         has_cr = memchr(data, '\r', sz) != NULL;
230         free(data);
231         return has_cr;
232 }
233
234 static int crlf_to_git(const char *path, const char *src, size_t len,
235                        struct strbuf *buf,
236                        enum crlf_action crlf_action, enum safe_crlf checksafe)
237 {
238         struct text_stat stats;
239         char *dst;
240
241         if (crlf_action == CRLF_BINARY ||
242             (src && !len))
243                 return 0;
244
245         /*
246          * If we are doing a dry-run and have no source buffer, there is
247          * nothing to analyze; we must assume we would convert.
248          */
249         if (!buf && !src)
250                 return 1;
251
252         gather_stats(src, len, &stats);
253
254         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
255                 if (convert_is_binary(len, &stats))
256                         return 0;
257
258                 if (crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
259                         /*
260                          * If the file in the index has any CR in it, do not convert.
261                          * This is the new safer autocrlf handling.
262                          */
263                         if (has_cr_in_index(path))
264                                 return 0;
265                 }
266         }
267
268         check_safe_crlf(path, crlf_action, &stats, checksafe);
269
270         /* Optimization: No CRLF? Nothing to convert, regardless. */
271         if (!stats.crlf)
272                 return 0;
273
274         /*
275          * At this point all of our source analysis is done, and we are sure we
276          * would convert. If we are in dry-run mode, we can give an answer.
277          */
278         if (!buf)
279                 return 1;
280
281         /* only grow if not in place */
282         if (strbuf_avail(buf) + buf->len < len)
283                 strbuf_grow(buf, len - buf->len);
284         dst = buf->buf;
285         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
286                 /*
287                  * If we guessed, we already know we rejected a file with
288                  * lone CR, and we can strip a CR without looking at what
289                  * follow it.
290                  */
291                 do {
292                         unsigned char c = *src++;
293                         if (c != '\r')
294                                 *dst++ = c;
295                 } while (--len);
296         } else {
297                 do {
298                         unsigned char c = *src++;
299                         if (! (c == '\r' && (1 < len && *src == '\n')))
300                                 *dst++ = c;
301                 } while (--len);
302         }
303         strbuf_setlen(buf, dst - buf->buf);
304         return 1;
305 }
306
307 static int crlf_to_worktree(const char *path, const char *src, size_t len,
308                             struct strbuf *buf, enum crlf_action crlf_action)
309 {
310         char *to_free = NULL;
311         struct text_stat stats;
312
313         if (!len || output_eol(crlf_action) != EOL_CRLF)
314                 return 0;
315
316         gather_stats(src, len, &stats);
317
318         /* No "naked" LF? Nothing to convert, regardless. */
319         if (!stats.lonelf)
320                 return 0;
321
322         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
323                 if (crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
324                         /* If we have any CR or CRLF line endings, we do not touch it */
325                         /* This is the new safer autocrlf-handling */
326                         if (stats.lonecr || stats.crlf )
327                                 return 0;
328                 }
329
330                 if (convert_is_binary(len, &stats))
331                         return 0;
332         }
333
334         /* are we "faking" in place editing ? */
335         if (src == buf->buf)
336                 to_free = strbuf_detach(buf, NULL);
337
338         strbuf_grow(buf, len + stats.lonelf);
339         for (;;) {
340                 const char *nl = memchr(src, '\n', len);
341                 if (!nl)
342                         break;
343                 if (nl > src && nl[-1] == '\r') {
344                         strbuf_add(buf, src, nl + 1 - src);
345                 } else {
346                         strbuf_add(buf, src, nl - src);
347                         strbuf_addstr(buf, "\r\n");
348                 }
349                 len -= nl + 1 - src;
350                 src  = nl + 1;
351         }
352         strbuf_add(buf, src, len);
353
354         free(to_free);
355         return 1;
356 }
357
358 struct filter_params {
359         const char *src;
360         unsigned long size;
361         int fd;
362         const char *cmd;
363         const char *path;
364 };
365
366 static int filter_buffer_or_fd(int in, int out, void *data)
367 {
368         /*
369          * Spawn cmd and feed the buffer contents through its stdin.
370          */
371         struct child_process child_process = CHILD_PROCESS_INIT;
372         struct filter_params *params = (struct filter_params *)data;
373         int write_err, status;
374         const char *argv[] = { NULL, NULL };
375
376         /* apply % substitution to cmd */
377         struct strbuf cmd = STRBUF_INIT;
378         struct strbuf path = STRBUF_INIT;
379         struct strbuf_expand_dict_entry dict[] = {
380                 { "f", NULL, },
381                 { NULL, NULL, },
382         };
383
384         /* quote the path to preserve spaces, etc. */
385         sq_quote_buf(&path, params->path);
386         dict[0].value = path.buf;
387
388         /* expand all %f with the quoted path */
389         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
390         strbuf_release(&path);
391
392         argv[0] = cmd.buf;
393
394         child_process.argv = argv;
395         child_process.use_shell = 1;
396         child_process.in = -1;
397         child_process.out = out;
398
399         if (start_command(&child_process))
400                 return error("cannot fork to run external filter %s", params->cmd);
401
402         sigchain_push(SIGPIPE, SIG_IGN);
403
404         if (params->src) {
405                 write_err = (write_in_full(child_process.in,
406                                            params->src, params->size) < 0);
407                 if (errno == EPIPE)
408                         write_err = 0;
409         } else {
410                 write_err = copy_fd(params->fd, child_process.in);
411                 if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
412                         write_err = 0;
413         }
414
415         if (close(child_process.in))
416                 write_err = 1;
417         if (write_err)
418                 error("cannot feed the input to external filter %s", params->cmd);
419
420         sigchain_pop(SIGPIPE);
421
422         status = finish_command(&child_process);
423         if (status)
424                 error("external filter %s failed %d", params->cmd, status);
425
426         strbuf_release(&cmd);
427         return (write_err || status);
428 }
429
430 static int apply_filter(const char *path, const char *src, size_t len, int fd,
431                         struct strbuf *dst, const char *cmd)
432 {
433         /*
434          * Create a pipeline to have the command filter the buffer's
435          * contents.
436          *
437          * (child --> cmd) --> us
438          */
439         int ret = 1;
440         struct strbuf nbuf = STRBUF_INIT;
441         struct async async;
442         struct filter_params params;
443
444         if (!cmd || !*cmd)
445                 return 0;
446
447         if (!dst)
448                 return 1;
449
450         memset(&async, 0, sizeof(async));
451         async.proc = filter_buffer_or_fd;
452         async.data = &params;
453         async.out = -1;
454         params.src = src;
455         params.size = len;
456         params.fd = fd;
457         params.cmd = cmd;
458         params.path = path;
459
460         fflush(NULL);
461         if (start_async(&async))
462                 return 0;       /* error was already reported */
463
464         if (strbuf_read(&nbuf, async.out, len) < 0) {
465                 error("read from external filter %s failed", cmd);
466                 ret = 0;
467         }
468         if (close(async.out)) {
469                 error("read from external filter %s failed", cmd);
470                 ret = 0;
471         }
472         if (finish_async(&async)) {
473                 error("external filter %s failed", cmd);
474                 ret = 0;
475         }
476
477         if (ret) {
478                 strbuf_swap(dst, &nbuf);
479         }
480         strbuf_release(&nbuf);
481         return ret;
482 }
483
484 static struct convert_driver {
485         const char *name;
486         struct convert_driver *next;
487         const char *smudge;
488         const char *clean;
489         int required;
490 } *user_convert, **user_convert_tail;
491
492 static int read_convert_config(const char *var, const char *value, void *cb)
493 {
494         const char *key, *name;
495         int namelen;
496         struct convert_driver *drv;
497
498         /*
499          * External conversion drivers are configured using
500          * "filter.<name>.variable".
501          */
502         if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
503                 return 0;
504         for (drv = user_convert; drv; drv = drv->next)
505                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
506                         break;
507         if (!drv) {
508                 drv = xcalloc(1, sizeof(struct convert_driver));
509                 drv->name = xmemdupz(name, namelen);
510                 *user_convert_tail = drv;
511                 user_convert_tail = &(drv->next);
512         }
513
514         /*
515          * filter.<name>.smudge and filter.<name>.clean specifies
516          * the command line:
517          *
518          *      command-line
519          *
520          * The command-line will not be interpolated in any way.
521          */
522
523         if (!strcmp("smudge", key))
524                 return git_config_string(&drv->smudge, var, value);
525
526         if (!strcmp("clean", key))
527                 return git_config_string(&drv->clean, var, value);
528
529         if (!strcmp("required", key)) {
530                 drv->required = git_config_bool(var, value);
531                 return 0;
532         }
533
534         return 0;
535 }
536
537 static int count_ident(const char *cp, unsigned long size)
538 {
539         /*
540          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
541          */
542         int cnt = 0;
543         char ch;
544
545         while (size) {
546                 ch = *cp++;
547                 size--;
548                 if (ch != '$')
549                         continue;
550                 if (size < 3)
551                         break;
552                 if (memcmp("Id", cp, 2))
553                         continue;
554                 ch = cp[2];
555                 cp += 3;
556                 size -= 3;
557                 if (ch == '$')
558                         cnt++; /* $Id$ */
559                 if (ch != ':')
560                         continue;
561
562                 /*
563                  * "$Id: ... "; scan up to the closing dollar sign and discard.
564                  */
565                 while (size) {
566                         ch = *cp++;
567                         size--;
568                         if (ch == '$') {
569                                 cnt++;
570                                 break;
571                         }
572                         if (ch == '\n')
573                                 break;
574                 }
575         }
576         return cnt;
577 }
578
579 static int ident_to_git(const char *path, const char *src, size_t len,
580                         struct strbuf *buf, int ident)
581 {
582         char *dst, *dollar;
583
584         if (!ident || (src && !count_ident(src, len)))
585                 return 0;
586
587         if (!buf)
588                 return 1;
589
590         /* only grow if not in place */
591         if (strbuf_avail(buf) + buf->len < len)
592                 strbuf_grow(buf, len - buf->len);
593         dst = buf->buf;
594         for (;;) {
595                 dollar = memchr(src, '$', len);
596                 if (!dollar)
597                         break;
598                 memmove(dst, src, dollar + 1 - src);
599                 dst += dollar + 1 - src;
600                 len -= dollar + 1 - src;
601                 src  = dollar + 1;
602
603                 if (len > 3 && !memcmp(src, "Id:", 3)) {
604                         dollar = memchr(src + 3, '$', len - 3);
605                         if (!dollar)
606                                 break;
607                         if (memchr(src + 3, '\n', dollar - src - 3)) {
608                                 /* Line break before the next dollar. */
609                                 continue;
610                         }
611
612                         memcpy(dst, "Id$", 3);
613                         dst += 3;
614                         len -= dollar + 1 - src;
615                         src  = dollar + 1;
616                 }
617         }
618         memmove(dst, src, len);
619         strbuf_setlen(buf, dst + len - buf->buf);
620         return 1;
621 }
622
623 static int ident_to_worktree(const char *path, const char *src, size_t len,
624                              struct strbuf *buf, int ident)
625 {
626         unsigned char sha1[20];
627         char *to_free = NULL, *dollar, *spc;
628         int cnt;
629
630         if (!ident)
631                 return 0;
632
633         cnt = count_ident(src, len);
634         if (!cnt)
635                 return 0;
636
637         /* are we "faking" in place editing ? */
638         if (src == buf->buf)
639                 to_free = strbuf_detach(buf, NULL);
640         hash_sha1_file(src, len, "blob", sha1);
641
642         strbuf_grow(buf, len + cnt * 43);
643         for (;;) {
644                 /* step 1: run to the next '$' */
645                 dollar = memchr(src, '$', len);
646                 if (!dollar)
647                         break;
648                 strbuf_add(buf, src, dollar + 1 - src);
649                 len -= dollar + 1 - src;
650                 src  = dollar + 1;
651
652                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
653                 if (len < 3 || memcmp("Id", src, 2))
654                         continue;
655
656                 /* step 3: skip over Id$ or Id:xxxxx$ */
657                 if (src[2] == '$') {
658                         src += 3;
659                         len -= 3;
660                 } else if (src[2] == ':') {
661                         /*
662                          * It's possible that an expanded Id has crept its way into the
663                          * repository, we cope with that by stripping the expansion out.
664                          * This is probably not a good idea, since it will cause changes
665                          * on checkout, which won't go away by stash, but let's keep it
666                          * for git-style ids.
667                          */
668                         dollar = memchr(src + 3, '$', len - 3);
669                         if (!dollar) {
670                                 /* incomplete keyword, no more '$', so just quit the loop */
671                                 break;
672                         }
673
674                         if (memchr(src + 3, '\n', dollar - src - 3)) {
675                                 /* Line break before the next dollar. */
676                                 continue;
677                         }
678
679                         spc = memchr(src + 4, ' ', dollar - src - 4);
680                         if (spc && spc < dollar-1) {
681                                 /* There are spaces in unexpected places.
682                                  * This is probably an id from some other
683                                  * versioning system. Keep it for now.
684                                  */
685                                 continue;
686                         }
687
688                         len -= dollar + 1 - src;
689                         src  = dollar + 1;
690                 } else {
691                         /* it wasn't a "Id$" or "Id:xxxx$" */
692                         continue;
693                 }
694
695                 /* step 4: substitute */
696                 strbuf_addstr(buf, "Id: ");
697                 strbuf_add(buf, sha1_to_hex(sha1), 40);
698                 strbuf_addstr(buf, " $");
699         }
700         strbuf_add(buf, src, len);
701
702         free(to_free);
703         return 1;
704 }
705
706 static enum crlf_action git_path_check_crlf(struct git_attr_check *check)
707 {
708         const char *value = check->value;
709
710         if (ATTR_TRUE(value))
711                 return CRLF_TEXT;
712         else if (ATTR_FALSE(value))
713                 return CRLF_BINARY;
714         else if (ATTR_UNSET(value))
715                 ;
716         else if (!strcmp(value, "input"))
717                 return CRLF_TEXT_INPUT;
718         else if (!strcmp(value, "auto"))
719                 return CRLF_AUTO;
720         return CRLF_UNDEFINED;
721 }
722
723 static enum eol git_path_check_eol(struct git_attr_check *check)
724 {
725         const char *value = check->value;
726
727         if (ATTR_UNSET(value))
728                 ;
729         else if (!strcmp(value, "lf"))
730                 return EOL_LF;
731         else if (!strcmp(value, "crlf"))
732                 return EOL_CRLF;
733         return EOL_UNSET;
734 }
735
736 static struct convert_driver *git_path_check_convert(struct git_attr_check *check)
737 {
738         const char *value = check->value;
739         struct convert_driver *drv;
740
741         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
742                 return NULL;
743         for (drv = user_convert; drv; drv = drv->next)
744                 if (!strcmp(value, drv->name))
745                         return drv;
746         return NULL;
747 }
748
749 static int git_path_check_ident(struct git_attr_check *check)
750 {
751         const char *value = check->value;
752
753         return !!ATTR_TRUE(value);
754 }
755
756 struct conv_attrs {
757         struct convert_driver *drv;
758         enum crlf_action attr_action; /* What attr says */
759         enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
760         int ident;
761 };
762
763 static const char *conv_attr_name[] = {
764         "crlf", "ident", "filter", "eol", "text",
765 };
766 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
767
768 static void convert_attrs(struct conv_attrs *ca, const char *path)
769 {
770         int i;
771         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
772
773         if (!ccheck[0].attr) {
774                 for (i = 0; i < NUM_CONV_ATTRS; i++)
775                         ccheck[i].attr = git_attr(conv_attr_name[i]);
776                 user_convert_tail = &user_convert;
777                 git_config(read_convert_config, NULL);
778         }
779
780         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
781                 ca->crlf_action = git_path_check_crlf(ccheck + 4);
782                 if (ca->crlf_action == CRLF_UNDEFINED)
783                         ca->crlf_action = git_path_check_crlf(ccheck + 0);
784                 ca->attr_action = ca->crlf_action;
785                 ca->ident = git_path_check_ident(ccheck + 1);
786                 ca->drv = git_path_check_convert(ccheck + 2);
787                 if (ca->crlf_action != CRLF_BINARY) {
788                         enum eol eol_attr = git_path_check_eol(ccheck + 3);
789                         if (eol_attr == EOL_LF)
790                                 ca->crlf_action = CRLF_TEXT_INPUT;
791                         else if (eol_attr == EOL_CRLF)
792                                 ca->crlf_action = CRLF_TEXT_CRLF;
793                 }
794                 ca->attr_action = ca->crlf_action;
795         } else {
796                 ca->drv = NULL;
797                 ca->crlf_action = CRLF_UNDEFINED;
798                 ca->ident = 0;
799         }
800         if (ca->crlf_action == CRLF_TEXT)
801                 ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
802         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
803                 ca->crlf_action = CRLF_BINARY;
804         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
805                 ca->crlf_action = CRLF_AUTO_CRLF;
806         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
807                 ca->crlf_action = CRLF_AUTO_INPUT;
808 }
809
810 int would_convert_to_git_filter_fd(const char *path)
811 {
812         struct conv_attrs ca;
813
814         convert_attrs(&ca, path);
815         if (!ca.drv)
816                 return 0;
817
818         /*
819          * Apply a filter to an fd only if the filter is required to succeed.
820          * We must die if the filter fails, because the original data before
821          * filtering is not available.
822          */
823         if (!ca.drv->required)
824                 return 0;
825
826         return apply_filter(path, NULL, 0, -1, NULL, ca.drv->clean);
827 }
828
829 const char *get_convert_attr_ascii(const char *path)
830 {
831         struct conv_attrs ca;
832
833         convert_attrs(&ca, path);
834         switch (ca.attr_action) {
835         case CRLF_UNDEFINED:
836                 return "";
837         case CRLF_BINARY:
838                 return "-text";
839         case CRLF_TEXT:
840                 return "text";
841         case CRLF_TEXT_INPUT:
842                 return "text eol=lf";
843         case CRLF_TEXT_CRLF:
844                 return "text eol=crlf";
845         case CRLF_AUTO:
846                 return "text=auto";
847         case CRLF_AUTO_CRLF:
848                 return "text=auto eol=crlf"; /* This is not supported yet */
849         case CRLF_AUTO_INPUT:
850                 return "text=auto eol=lf"; /* This is not supported yet */
851         }
852         return "";
853 }
854
855 int convert_to_git(const char *path, const char *src, size_t len,
856                    struct strbuf *dst, enum safe_crlf checksafe)
857 {
858         int ret = 0;
859         const char *filter = NULL;
860         int required = 0;
861         struct conv_attrs ca;
862
863         convert_attrs(&ca, path);
864         if (ca.drv) {
865                 filter = ca.drv->clean;
866                 required = ca.drv->required;
867         }
868
869         ret |= apply_filter(path, src, len, -1, dst, filter);
870         if (!ret && required)
871                 die("%s: clean filter '%s' failed", path, ca.drv->name);
872
873         if (ret && dst) {
874                 src = dst->buf;
875                 len = dst->len;
876         }
877         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
878         if (ret && dst) {
879                 src = dst->buf;
880                 len = dst->len;
881         }
882         return ret | ident_to_git(path, src, len, dst, ca.ident);
883 }
884
885 void convert_to_git_filter_fd(const char *path, int fd, struct strbuf *dst,
886                               enum safe_crlf checksafe)
887 {
888         struct conv_attrs ca;
889         convert_attrs(&ca, path);
890
891         assert(ca.drv);
892         assert(ca.drv->clean);
893
894         if (!apply_filter(path, NULL, 0, fd, dst, ca.drv->clean))
895                 die("%s: clean filter '%s' failed", path, ca.drv->name);
896
897         crlf_to_git(path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
898         ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
899 }
900
901 static int convert_to_working_tree_internal(const char *path, const char *src,
902                                             size_t len, struct strbuf *dst,
903                                             int normalizing)
904 {
905         int ret = 0, ret_filter = 0;
906         const char *filter = NULL;
907         int required = 0;
908         struct conv_attrs ca;
909
910         convert_attrs(&ca, path);
911         if (ca.drv) {
912                 filter = ca.drv->smudge;
913                 required = ca.drv->required;
914         }
915
916         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
917         if (ret) {
918                 src = dst->buf;
919                 len = dst->len;
920         }
921         /*
922          * CRLF conversion can be skipped if normalizing, unless there
923          * is a smudge filter.  The filter might expect CRLFs.
924          */
925         if (filter || !normalizing) {
926                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
927                 if (ret) {
928                         src = dst->buf;
929                         len = dst->len;
930                 }
931         }
932
933         ret_filter = apply_filter(path, src, len, -1, dst, filter);
934         if (!ret_filter && required)
935                 die("%s: smudge filter %s failed", path, ca.drv->name);
936
937         return ret | ret_filter;
938 }
939
940 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
941 {
942         return convert_to_working_tree_internal(path, src, len, dst, 0);
943 }
944
945 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
946 {
947         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
948         if (ret) {
949                 src = dst->buf;
950                 len = dst->len;
951         }
952         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
953 }
954
955 /*****************************************************************
956  *
957  * Streaming conversion support
958  *
959  *****************************************************************/
960
961 typedef int (*filter_fn)(struct stream_filter *,
962                          const char *input, size_t *isize_p,
963                          char *output, size_t *osize_p);
964 typedef void (*free_fn)(struct stream_filter *);
965
966 struct stream_filter_vtbl {
967         filter_fn filter;
968         free_fn free;
969 };
970
971 struct stream_filter {
972         struct stream_filter_vtbl *vtbl;
973 };
974
975 static int null_filter_fn(struct stream_filter *filter,
976                           const char *input, size_t *isize_p,
977                           char *output, size_t *osize_p)
978 {
979         size_t count;
980
981         if (!input)
982                 return 0; /* we do not keep any states */
983         count = *isize_p;
984         if (*osize_p < count)
985                 count = *osize_p;
986         if (count) {
987                 memmove(output, input, count);
988                 *isize_p -= count;
989                 *osize_p -= count;
990         }
991         return 0;
992 }
993
994 static void null_free_fn(struct stream_filter *filter)
995 {
996         ; /* nothing -- null instances are shared */
997 }
998
999 static struct stream_filter_vtbl null_vtbl = {
1000         null_filter_fn,
1001         null_free_fn,
1002 };
1003
1004 static struct stream_filter null_filter_singleton = {
1005         &null_vtbl,
1006 };
1007
1008 int is_null_stream_filter(struct stream_filter *filter)
1009 {
1010         return filter == &null_filter_singleton;
1011 }
1012
1013
1014 /*
1015  * LF-to-CRLF filter
1016  */
1017
1018 struct lf_to_crlf_filter {
1019         struct stream_filter filter;
1020         unsigned has_held:1;
1021         char held;
1022 };
1023
1024 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1025                                 const char *input, size_t *isize_p,
1026                                 char *output, size_t *osize_p)
1027 {
1028         size_t count, o = 0;
1029         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1030
1031         /*
1032          * We may be holding onto the CR to see if it is followed by a
1033          * LF, in which case we would need to go to the main loop.
1034          * Otherwise, just emit it to the output stream.
1035          */
1036         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1037                 output[o++] = lf_to_crlf->held;
1038                 lf_to_crlf->has_held = 0;
1039         }
1040
1041         /* We are told to drain */
1042         if (!input) {
1043                 *osize_p -= o;
1044                 return 0;
1045         }
1046
1047         count = *isize_p;
1048         if (count || lf_to_crlf->has_held) {
1049                 size_t i;
1050                 int was_cr = 0;
1051
1052                 if (lf_to_crlf->has_held) {
1053                         was_cr = 1;
1054                         lf_to_crlf->has_held = 0;
1055                 }
1056
1057                 for (i = 0; o < *osize_p && i < count; i++) {
1058                         char ch = input[i];
1059
1060                         if (ch == '\n') {
1061                                 output[o++] = '\r';
1062                         } else if (was_cr) {
1063                                 /*
1064                                  * Previous round saw CR and it is not followed
1065                                  * by a LF; emit the CR before processing the
1066                                  * current character.
1067                                  */
1068                                 output[o++] = '\r';
1069                         }
1070
1071                         /*
1072                          * We may have consumed the last output slot,
1073                          * in which case we need to break out of this
1074                          * loop; hold the current character before
1075                          * returning.
1076                          */
1077                         if (*osize_p <= o) {
1078                                 lf_to_crlf->has_held = 1;
1079                                 lf_to_crlf->held = ch;
1080                                 continue; /* break but increment i */
1081                         }
1082
1083                         if (ch == '\r') {
1084                                 was_cr = 1;
1085                                 continue;
1086                         }
1087
1088                         was_cr = 0;
1089                         output[o++] = ch;
1090                 }
1091
1092                 *osize_p -= o;
1093                 *isize_p -= i;
1094
1095                 if (!lf_to_crlf->has_held && was_cr) {
1096                         lf_to_crlf->has_held = 1;
1097                         lf_to_crlf->held = '\r';
1098                 }
1099         }
1100         return 0;
1101 }
1102
1103 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1104 {
1105         free(filter);
1106 }
1107
1108 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1109         lf_to_crlf_filter_fn,
1110         lf_to_crlf_free_fn,
1111 };
1112
1113 static struct stream_filter *lf_to_crlf_filter(void)
1114 {
1115         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1116
1117         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1118         return (struct stream_filter *)lf_to_crlf;
1119 }
1120
1121 /*
1122  * Cascade filter
1123  */
1124 #define FILTER_BUFFER 1024
1125 struct cascade_filter {
1126         struct stream_filter filter;
1127         struct stream_filter *one;
1128         struct stream_filter *two;
1129         char buf[FILTER_BUFFER];
1130         int end, ptr;
1131 };
1132
1133 static int cascade_filter_fn(struct stream_filter *filter,
1134                              const char *input, size_t *isize_p,
1135                              char *output, size_t *osize_p)
1136 {
1137         struct cascade_filter *cas = (struct cascade_filter *) filter;
1138         size_t filled = 0;
1139         size_t sz = *osize_p;
1140         size_t to_feed, remaining;
1141
1142         /*
1143          * input -- (one) --> buf -- (two) --> output
1144          */
1145         while (filled < sz) {
1146                 remaining = sz - filled;
1147
1148                 /* do we already have something to feed two with? */
1149                 if (cas->ptr < cas->end) {
1150                         to_feed = cas->end - cas->ptr;
1151                         if (stream_filter(cas->two,
1152                                           cas->buf + cas->ptr, &to_feed,
1153                                           output + filled, &remaining))
1154                                 return -1;
1155                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1156                         filled = sz - remaining;
1157                         continue;
1158                 }
1159
1160                 /* feed one from upstream and have it emit into our buffer */
1161                 to_feed = input ? *isize_p : 0;
1162                 if (input && !to_feed)
1163                         break;
1164                 remaining = sizeof(cas->buf);
1165                 if (stream_filter(cas->one,
1166                                   input, &to_feed,
1167                                   cas->buf, &remaining))
1168                         return -1;
1169                 cas->end = sizeof(cas->buf) - remaining;
1170                 cas->ptr = 0;
1171                 if (input) {
1172                         size_t fed = *isize_p - to_feed;
1173                         *isize_p -= fed;
1174                         input += fed;
1175                 }
1176
1177                 /* do we know that we drained one completely? */
1178                 if (input || cas->end)
1179                         continue;
1180
1181                 /* tell two to drain; we have nothing more to give it */
1182                 to_feed = 0;
1183                 remaining = sz - filled;
1184                 if (stream_filter(cas->two,
1185                                   NULL, &to_feed,
1186                                   output + filled, &remaining))
1187                         return -1;
1188                 if (remaining == (sz - filled))
1189                         break; /* completely drained two */
1190                 filled = sz - remaining;
1191         }
1192         *osize_p -= filled;
1193         return 0;
1194 }
1195
1196 static void cascade_free_fn(struct stream_filter *filter)
1197 {
1198         struct cascade_filter *cas = (struct cascade_filter *)filter;
1199         free_stream_filter(cas->one);
1200         free_stream_filter(cas->two);
1201         free(filter);
1202 }
1203
1204 static struct stream_filter_vtbl cascade_vtbl = {
1205         cascade_filter_fn,
1206         cascade_free_fn,
1207 };
1208
1209 static struct stream_filter *cascade_filter(struct stream_filter *one,
1210                                             struct stream_filter *two)
1211 {
1212         struct cascade_filter *cascade;
1213
1214         if (!one || is_null_stream_filter(one))
1215                 return two;
1216         if (!two || is_null_stream_filter(two))
1217                 return one;
1218
1219         cascade = xmalloc(sizeof(*cascade));
1220         cascade->one = one;
1221         cascade->two = two;
1222         cascade->end = cascade->ptr = 0;
1223         cascade->filter.vtbl = &cascade_vtbl;
1224         return (struct stream_filter *)cascade;
1225 }
1226
1227 /*
1228  * ident filter
1229  */
1230 #define IDENT_DRAINING (-1)
1231 #define IDENT_SKIPPING (-2)
1232 struct ident_filter {
1233         struct stream_filter filter;
1234         struct strbuf left;
1235         int state;
1236         char ident[45]; /* ": x40 $" */
1237 };
1238
1239 static int is_foreign_ident(const char *str)
1240 {
1241         int i;
1242
1243         if (!skip_prefix(str, "$Id: ", &str))
1244                 return 0;
1245         for (i = 0; str[i]; i++) {
1246                 if (isspace(str[i]) && str[i+1] != '$')
1247                         return 1;
1248         }
1249         return 0;
1250 }
1251
1252 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1253 {
1254         size_t to_drain = ident->left.len;
1255
1256         if (*osize_p < to_drain)
1257                 to_drain = *osize_p;
1258         if (to_drain) {
1259                 memcpy(*output_p, ident->left.buf, to_drain);
1260                 strbuf_remove(&ident->left, 0, to_drain);
1261                 *output_p += to_drain;
1262                 *osize_p -= to_drain;
1263         }
1264         if (!ident->left.len)
1265                 ident->state = 0;
1266 }
1267
1268 static int ident_filter_fn(struct stream_filter *filter,
1269                            const char *input, size_t *isize_p,
1270                            char *output, size_t *osize_p)
1271 {
1272         struct ident_filter *ident = (struct ident_filter *)filter;
1273         static const char head[] = "$Id";
1274
1275         if (!input) {
1276                 /* drain upon eof */
1277                 switch (ident->state) {
1278                 default:
1279                         strbuf_add(&ident->left, head, ident->state);
1280                 case IDENT_SKIPPING:
1281                         /* fallthru */
1282                 case IDENT_DRAINING:
1283                         ident_drain(ident, &output, osize_p);
1284                 }
1285                 return 0;
1286         }
1287
1288         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1289                 int ch;
1290
1291                 if (ident->state == IDENT_DRAINING) {
1292                         ident_drain(ident, &output, osize_p);
1293                         if (!*osize_p)
1294                                 break;
1295                         continue;
1296                 }
1297
1298                 ch = *(input++);
1299                 (*isize_p)--;
1300
1301                 if (ident->state == IDENT_SKIPPING) {
1302                         /*
1303                          * Skipping until '$' or LF, but keeping them
1304                          * in case it is a foreign ident.
1305                          */
1306                         strbuf_addch(&ident->left, ch);
1307                         if (ch != '\n' && ch != '$')
1308                                 continue;
1309                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1310                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1311                                 strbuf_addstr(&ident->left, ident->ident);
1312                         }
1313                         ident->state = IDENT_DRAINING;
1314                         continue;
1315                 }
1316
1317                 if (ident->state < sizeof(head) &&
1318                     head[ident->state] == ch) {
1319                         ident->state++;
1320                         continue;
1321                 }
1322
1323                 if (ident->state)
1324                         strbuf_add(&ident->left, head, ident->state);
1325                 if (ident->state == sizeof(head) - 1) {
1326                         if (ch != ':' && ch != '$') {
1327                                 strbuf_addch(&ident->left, ch);
1328                                 ident->state = 0;
1329                                 continue;
1330                         }
1331
1332                         if (ch == ':') {
1333                                 strbuf_addch(&ident->left, ch);
1334                                 ident->state = IDENT_SKIPPING;
1335                         } else {
1336                                 strbuf_addstr(&ident->left, ident->ident);
1337                                 ident->state = IDENT_DRAINING;
1338                         }
1339                         continue;
1340                 }
1341
1342                 strbuf_addch(&ident->left, ch);
1343                 ident->state = IDENT_DRAINING;
1344         }
1345         return 0;
1346 }
1347
1348 static void ident_free_fn(struct stream_filter *filter)
1349 {
1350         struct ident_filter *ident = (struct ident_filter *)filter;
1351         strbuf_release(&ident->left);
1352         free(filter);
1353 }
1354
1355 static struct stream_filter_vtbl ident_vtbl = {
1356         ident_filter_fn,
1357         ident_free_fn,
1358 };
1359
1360 static struct stream_filter *ident_filter(const unsigned char *sha1)
1361 {
1362         struct ident_filter *ident = xmalloc(sizeof(*ident));
1363
1364         xsnprintf(ident->ident, sizeof(ident->ident),
1365                   ": %s $", sha1_to_hex(sha1));
1366         strbuf_init(&ident->left, 0);
1367         ident->filter.vtbl = &ident_vtbl;
1368         ident->state = 0;
1369         return (struct stream_filter *)ident;
1370 }
1371
1372 /*
1373  * Return an appropriately constructed filter for the path, or NULL if
1374  * the contents cannot be filtered without reading the whole thing
1375  * in-core.
1376  *
1377  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1378  * large binary blob you would want us not to slurp into the memory!
1379  */
1380 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1381 {
1382         struct conv_attrs ca;
1383         enum crlf_action crlf_action;
1384         struct stream_filter *filter = NULL;
1385
1386         convert_attrs(&ca, path);
1387
1388         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1389                 return filter;
1390
1391         if (ca.ident)
1392                 filter = ident_filter(sha1);
1393
1394         crlf_action = ca.crlf_action;
1395
1396         if ((crlf_action == CRLF_BINARY) ||
1397                         crlf_action == CRLF_AUTO_INPUT ||
1398                         (crlf_action == CRLF_TEXT_INPUT))
1399                 filter = cascade_filter(filter, &null_filter_singleton);
1400
1401         else if (output_eol(crlf_action) == EOL_CRLF &&
1402                  !(crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_CRLF))
1403                 filter = cascade_filter(filter, lf_to_crlf_filter());
1404
1405         return filter;
1406 }
1407
1408 void free_stream_filter(struct stream_filter *filter)
1409 {
1410         filter->vtbl->free(filter);
1411 }
1412
1413 int stream_filter(struct stream_filter *filter,
1414                   const char *input, size_t *isize_p,
1415                   char *output, size_t *osize_p)
1416 {
1417         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1418 }