merge --stat: use the full terminal width
[git] / convert.c
1 #include "cache.h"
2 #include "attr.h"
3 #include "run-command.h"
4 #include "quote.h"
5
6 /*
7  * convert.c - convert a file when checking it out and checking it in.
8  *
9  * This should use the pathname to decide on whether it wants to do some
10  * more interesting conversions (automatic gzip/unzip, general format
11  * conversions etc etc), but by default it just does automatic CRLF<->LF
12  * translation when the "text" attribute or "auto_crlf" option is set.
13  */
14
15 enum crlf_action {
16         CRLF_GUESS = -1,
17         CRLF_BINARY = 0,
18         CRLF_TEXT,
19         CRLF_INPUT,
20         CRLF_CRLF,
21         CRLF_AUTO
22 };
23
24 struct text_stat {
25         /* NUL, CR, LF and CRLF counts */
26         unsigned nul, cr, lf, crlf;
27
28         /* These are just approximations! */
29         unsigned printable, nonprintable;
30 };
31
32 static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
33 {
34         unsigned long i;
35
36         memset(stats, 0, sizeof(*stats));
37
38         for (i = 0; i < size; i++) {
39                 unsigned char c = buf[i];
40                 if (c == '\r') {
41                         stats->cr++;
42                         if (i+1 < size && buf[i+1] == '\n')
43                                 stats->crlf++;
44                         continue;
45                 }
46                 if (c == '\n') {
47                         stats->lf++;
48                         continue;
49                 }
50                 if (c == 127)
51                         /* DEL */
52                         stats->nonprintable++;
53                 else if (c < 32) {
54                         switch (c) {
55                                 /* BS, HT, ESC and FF */
56                         case '\b': case '\t': case '\033': case '\014':
57                                 stats->printable++;
58                                 break;
59                         case 0:
60                                 stats->nul++;
61                                 /* fall through */
62                         default:
63                                 stats->nonprintable++;
64                         }
65                 }
66                 else
67                         stats->printable++;
68         }
69
70         /* If file ends with EOF then don't count this EOF as non-printable. */
71         if (size >= 1 && buf[size-1] == '\032')
72                 stats->nonprintable--;
73 }
74
75 /*
76  * The same heuristics as diff.c::mmfile_is_binary()
77  */
78 static int is_binary(unsigned long size, struct text_stat *stats)
79 {
80
81         if (stats->nul)
82                 return 1;
83         if ((stats->printable >> 7) < stats->nonprintable)
84                 return 1;
85         /*
86          * Other heuristics? Average line length might be relevant,
87          * as might LF vs CR vs CRLF counts..
88          *
89          * NOTE! It might be normal to have a low ratio of CRLF to LF
90          * (somebody starts with a LF-only file and edits it with an editor
91          * that adds CRLF only to lines that are added..). But do  we
92          * want to support CR-only? Probably not.
93          */
94         return 0;
95 }
96
97 static enum eol output_eol(enum crlf_action crlf_action)
98 {
99         switch (crlf_action) {
100         case CRLF_BINARY:
101                 return EOL_UNSET;
102         case CRLF_CRLF:
103                 return EOL_CRLF;
104         case CRLF_INPUT:
105                 return EOL_LF;
106         case CRLF_GUESS:
107                 if (!auto_crlf)
108                         return EOL_UNSET;
109                 /* fall through */
110         case CRLF_TEXT:
111         case CRLF_AUTO:
112                 if (auto_crlf == AUTO_CRLF_TRUE)
113                         return EOL_CRLF;
114                 else if (auto_crlf == AUTO_CRLF_INPUT)
115                         return EOL_LF;
116                 else if (core_eol == EOL_UNSET)
117                         return EOL_NATIVE;
118         }
119         return core_eol;
120 }
121
122 static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
123                             struct text_stat *stats, enum safe_crlf checksafe)
124 {
125         if (!checksafe)
126                 return;
127
128         if (output_eol(crlf_action) == EOL_LF) {
129                 /*
130                  * CRLFs would not be restored by checkout:
131                  * check if we'd remove CRLFs
132                  */
133                 if (stats->crlf) {
134                         if (checksafe == SAFE_CRLF_WARN)
135                                 warning("CRLF will be replaced by LF in %s.\nThe file will have its original line endings in your working directory.", path);
136                         else /* i.e. SAFE_CRLF_FAIL */
137                                 die("CRLF would be replaced by LF in %s.", path);
138                 }
139         } else if (output_eol(crlf_action) == EOL_CRLF) {
140                 /*
141                  * CRLFs would be added by checkout:
142                  * check if we have "naked" LFs
143                  */
144                 if (stats->lf != stats->crlf) {
145                         if (checksafe == SAFE_CRLF_WARN)
146                                 warning("LF will be replaced by CRLF in %s.\nThe file will have its original line endings in your working directory.", path);
147                         else /* i.e. SAFE_CRLF_FAIL */
148                                 die("LF would be replaced by CRLF in %s", path);
149                 }
150         }
151 }
152
153 static int has_cr_in_index(const char *path)
154 {
155         int pos, len;
156         unsigned long sz;
157         enum object_type type;
158         void *data;
159         int has_cr;
160         struct index_state *istate = &the_index;
161
162         len = strlen(path);
163         pos = index_name_pos(istate, path, len);
164         if (pos < 0) {
165                 /*
166                  * We might be in the middle of a merge, in which
167                  * case we would read stage #2 (ours).
168                  */
169                 int i;
170                 for (i = -pos - 1;
171                      (pos < 0 && i < istate->cache_nr &&
172                       !strcmp(istate->cache[i]->name, path));
173                      i++)
174                         if (ce_stage(istate->cache[i]) == 2)
175                                 pos = i;
176         }
177         if (pos < 0)
178                 return 0;
179         data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
180         if (!data || type != OBJ_BLOB) {
181                 free(data);
182                 return 0;
183         }
184
185         has_cr = memchr(data, '\r', sz) != NULL;
186         free(data);
187         return has_cr;
188 }
189
190 static int crlf_to_git(const char *path, const char *src, size_t len,
191                        struct strbuf *buf,
192                        enum crlf_action crlf_action, enum safe_crlf checksafe)
193 {
194         struct text_stat stats;
195         char *dst;
196
197         if (crlf_action == CRLF_BINARY ||
198             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE) || !len)
199                 return 0;
200
201         gather_stats(src, len, &stats);
202
203         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
204                 /*
205                  * We're currently not going to even try to convert stuff
206                  * that has bare CR characters. Does anybody do that crazy
207                  * stuff?
208                  */
209                 if (stats.cr != stats.crlf)
210                         return 0;
211
212                 /*
213                  * And add some heuristics for binary vs text, of course...
214                  */
215                 if (is_binary(len, &stats))
216                         return 0;
217
218                 if (crlf_action == CRLF_GUESS) {
219                         /*
220                          * If the file in the index has any CR in it, do not convert.
221                          * This is the new safer autocrlf handling.
222                          */
223                         if (has_cr_in_index(path))
224                                 return 0;
225                 }
226         }
227
228         check_safe_crlf(path, crlf_action, &stats, checksafe);
229
230         /* Optimization: No CR? Nothing to convert, regardless. */
231         if (!stats.cr)
232                 return 0;
233
234         /* only grow if not in place */
235         if (strbuf_avail(buf) + buf->len < len)
236                 strbuf_grow(buf, len - buf->len);
237         dst = buf->buf;
238         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
239                 /*
240                  * If we guessed, we already know we rejected a file with
241                  * lone CR, and we can strip a CR without looking at what
242                  * follow it.
243                  */
244                 do {
245                         unsigned char c = *src++;
246                         if (c != '\r')
247                                 *dst++ = c;
248                 } while (--len);
249         } else {
250                 do {
251                         unsigned char c = *src++;
252                         if (! (c == '\r' && (1 < len && *src == '\n')))
253                                 *dst++ = c;
254                 } while (--len);
255         }
256         strbuf_setlen(buf, dst - buf->buf);
257         return 1;
258 }
259
260 static int crlf_to_worktree(const char *path, const char *src, size_t len,
261                             struct strbuf *buf, enum crlf_action crlf_action)
262 {
263         char *to_free = NULL;
264         struct text_stat stats;
265
266         if (!len || output_eol(crlf_action) != EOL_CRLF)
267                 return 0;
268
269         gather_stats(src, len, &stats);
270
271         /* No LF? Nothing to convert, regardless. */
272         if (!stats.lf)
273                 return 0;
274
275         /* Was it already in CRLF format? */
276         if (stats.lf == stats.crlf)
277                 return 0;
278
279         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
280                 if (crlf_action == CRLF_GUESS) {
281                         /* If we have any CR or CRLF line endings, we do not touch it */
282                         /* This is the new safer autocrlf-handling */
283                         if (stats.cr > 0 || stats.crlf > 0)
284                                 return 0;
285                 }
286
287                 /* If we have any bare CR characters, we're not going to touch it */
288                 if (stats.cr != stats.crlf)
289                         return 0;
290
291                 if (is_binary(len, &stats))
292                         return 0;
293         }
294
295         /* are we "faking" in place editing ? */
296         if (src == buf->buf)
297                 to_free = strbuf_detach(buf, NULL);
298
299         strbuf_grow(buf, len + stats.lf - stats.crlf);
300         for (;;) {
301                 const char *nl = memchr(src, '\n', len);
302                 if (!nl)
303                         break;
304                 if (nl > src && nl[-1] == '\r') {
305                         strbuf_add(buf, src, nl + 1 - src);
306                 } else {
307                         strbuf_add(buf, src, nl - src);
308                         strbuf_addstr(buf, "\r\n");
309                 }
310                 len -= nl + 1 - src;
311                 src  = nl + 1;
312         }
313         strbuf_add(buf, src, len);
314
315         free(to_free);
316         return 1;
317 }
318
319 struct filter_params {
320         const char *src;
321         unsigned long size;
322         const char *cmd;
323         const char *path;
324 };
325
326 static int filter_buffer(int in, int out, void *data)
327 {
328         /*
329          * Spawn cmd and feed the buffer contents through its stdin.
330          */
331         struct child_process child_process;
332         struct filter_params *params = (struct filter_params *)data;
333         int write_err, status;
334         const char *argv[] = { NULL, NULL };
335
336         /* apply % substitution to cmd */
337         struct strbuf cmd = STRBUF_INIT;
338         struct strbuf path = STRBUF_INIT;
339         struct strbuf_expand_dict_entry dict[] = {
340                 { "f", NULL, },
341                 { NULL, NULL, },
342         };
343
344         /* quote the path to preserve spaces, etc. */
345         sq_quote_buf(&path, params->path);
346         dict[0].value = path.buf;
347
348         /* expand all %f with the quoted path */
349         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
350         strbuf_release(&path);
351
352         argv[0] = cmd.buf;
353
354         memset(&child_process, 0, sizeof(child_process));
355         child_process.argv = argv;
356         child_process.use_shell = 1;
357         child_process.in = -1;
358         child_process.out = out;
359
360         if (start_command(&child_process))
361                 return error("cannot fork to run external filter %s", params->cmd);
362
363         write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
364         if (close(child_process.in))
365                 write_err = 1;
366         if (write_err)
367                 error("cannot feed the input to external filter %s", params->cmd);
368
369         status = finish_command(&child_process);
370         if (status)
371                 error("external filter %s failed %d", params->cmd, status);
372
373         strbuf_release(&cmd);
374         return (write_err || status);
375 }
376
377 static int apply_filter(const char *path, const char *src, size_t len,
378                         struct strbuf *dst, const char *cmd)
379 {
380         /*
381          * Create a pipeline to have the command filter the buffer's
382          * contents.
383          *
384          * (child --> cmd) --> us
385          */
386         int ret = 1;
387         struct strbuf nbuf = STRBUF_INIT;
388         struct async async;
389         struct filter_params params;
390
391         if (!cmd)
392                 return 0;
393
394         memset(&async, 0, sizeof(async));
395         async.proc = filter_buffer;
396         async.data = &params;
397         async.out = -1;
398         params.src = src;
399         params.size = len;
400         params.cmd = cmd;
401         params.path = path;
402
403         fflush(NULL);
404         if (start_async(&async))
405                 return 0;       /* error was already reported */
406
407         if (strbuf_read(&nbuf, async.out, len) < 0) {
408                 error("read from external filter %s failed", cmd);
409                 ret = 0;
410         }
411         if (close(async.out)) {
412                 error("read from external filter %s failed", cmd);
413                 ret = 0;
414         }
415         if (finish_async(&async)) {
416                 error("external filter %s failed", cmd);
417                 ret = 0;
418         }
419
420         if (ret) {
421                 strbuf_swap(dst, &nbuf);
422         }
423         strbuf_release(&nbuf);
424         return ret;
425 }
426
427 static struct convert_driver {
428         const char *name;
429         struct convert_driver *next;
430         const char *smudge;
431         const char *clean;
432 } *user_convert, **user_convert_tail;
433
434 static int read_convert_config(const char *var, const char *value, void *cb)
435 {
436         const char *ep, *name;
437         int namelen;
438         struct convert_driver *drv;
439
440         /*
441          * External conversion drivers are configured using
442          * "filter.<name>.variable".
443          */
444         if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
445                 return 0;
446         name = var + 7;
447         namelen = ep - name;
448         for (drv = user_convert; drv; drv = drv->next)
449                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
450                         break;
451         if (!drv) {
452                 drv = xcalloc(1, sizeof(struct convert_driver));
453                 drv->name = xmemdupz(name, namelen);
454                 *user_convert_tail = drv;
455                 user_convert_tail = &(drv->next);
456         }
457
458         ep++;
459
460         /*
461          * filter.<name>.smudge and filter.<name>.clean specifies
462          * the command line:
463          *
464          *      command-line
465          *
466          * The command-line will not be interpolated in any way.
467          */
468
469         if (!strcmp("smudge", ep))
470                 return git_config_string(&drv->smudge, var, value);
471
472         if (!strcmp("clean", ep))
473                 return git_config_string(&drv->clean, var, value);
474
475         return 0;
476 }
477
478 static int count_ident(const char *cp, unsigned long size)
479 {
480         /*
481          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
482          */
483         int cnt = 0;
484         char ch;
485
486         while (size) {
487                 ch = *cp++;
488                 size--;
489                 if (ch != '$')
490                         continue;
491                 if (size < 3)
492                         break;
493                 if (memcmp("Id", cp, 2))
494                         continue;
495                 ch = cp[2];
496                 cp += 3;
497                 size -= 3;
498                 if (ch == '$')
499                         cnt++; /* $Id$ */
500                 if (ch != ':')
501                         continue;
502
503                 /*
504                  * "$Id: ... "; scan up to the closing dollar sign and discard.
505                  */
506                 while (size) {
507                         ch = *cp++;
508                         size--;
509                         if (ch == '$') {
510                                 cnt++;
511                                 break;
512                         }
513                         if (ch == '\n')
514                                 break;
515                 }
516         }
517         return cnt;
518 }
519
520 static int ident_to_git(const char *path, const char *src, size_t len,
521                         struct strbuf *buf, int ident)
522 {
523         char *dst, *dollar;
524
525         if (!ident || !count_ident(src, len))
526                 return 0;
527
528         /* only grow if not in place */
529         if (strbuf_avail(buf) + buf->len < len)
530                 strbuf_grow(buf, len - buf->len);
531         dst = buf->buf;
532         for (;;) {
533                 dollar = memchr(src, '$', len);
534                 if (!dollar)
535                         break;
536                 memmove(dst, src, dollar + 1 - src);
537                 dst += dollar + 1 - src;
538                 len -= dollar + 1 - src;
539                 src  = dollar + 1;
540
541                 if (len > 3 && !memcmp(src, "Id:", 3)) {
542                         dollar = memchr(src + 3, '$', len - 3);
543                         if (!dollar)
544                                 break;
545                         if (memchr(src + 3, '\n', dollar - src - 3)) {
546                                 /* Line break before the next dollar. */
547                                 continue;
548                         }
549
550                         memcpy(dst, "Id$", 3);
551                         dst += 3;
552                         len -= dollar + 1 - src;
553                         src  = dollar + 1;
554                 }
555         }
556         memmove(dst, src, len);
557         strbuf_setlen(buf, dst + len - buf->buf);
558         return 1;
559 }
560
561 static int ident_to_worktree(const char *path, const char *src, size_t len,
562                              struct strbuf *buf, int ident)
563 {
564         unsigned char sha1[20];
565         char *to_free = NULL, *dollar, *spc;
566         int cnt;
567
568         if (!ident)
569                 return 0;
570
571         cnt = count_ident(src, len);
572         if (!cnt)
573                 return 0;
574
575         /* are we "faking" in place editing ? */
576         if (src == buf->buf)
577                 to_free = strbuf_detach(buf, NULL);
578         hash_sha1_file(src, len, "blob", sha1);
579
580         strbuf_grow(buf, len + cnt * 43);
581         for (;;) {
582                 /* step 1: run to the next '$' */
583                 dollar = memchr(src, '$', len);
584                 if (!dollar)
585                         break;
586                 strbuf_add(buf, src, dollar + 1 - src);
587                 len -= dollar + 1 - src;
588                 src  = dollar + 1;
589
590                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
591                 if (len < 3 || memcmp("Id", src, 2))
592                         continue;
593
594                 /* step 3: skip over Id$ or Id:xxxxx$ */
595                 if (src[2] == '$') {
596                         src += 3;
597                         len -= 3;
598                 } else if (src[2] == ':') {
599                         /*
600                          * It's possible that an expanded Id has crept its way into the
601                          * repository, we cope with that by stripping the expansion out.
602                          * This is probably not a good idea, since it will cause changes
603                          * on checkout, which won't go away by stash, but let's keep it
604                          * for git-style ids.
605                          */
606                         dollar = memchr(src + 3, '$', len - 3);
607                         if (!dollar) {
608                                 /* incomplete keyword, no more '$', so just quit the loop */
609                                 break;
610                         }
611
612                         if (memchr(src + 3, '\n', dollar - src - 3)) {
613                                 /* Line break before the next dollar. */
614                                 continue;
615                         }
616
617                         spc = memchr(src + 4, ' ', dollar - src - 4);
618                         if (spc && spc < dollar-1) {
619                                 /* There are spaces in unexpected places.
620                                  * This is probably an id from some other
621                                  * versioning system. Keep it for now.
622                                  */
623                                 continue;
624                         }
625
626                         len -= dollar + 1 - src;
627                         src  = dollar + 1;
628                 } else {
629                         /* it wasn't a "Id$" or "Id:xxxx$" */
630                         continue;
631                 }
632
633                 /* step 4: substitute */
634                 strbuf_addstr(buf, "Id: ");
635                 strbuf_add(buf, sha1_to_hex(sha1), 40);
636                 strbuf_addstr(buf, " $");
637         }
638         strbuf_add(buf, src, len);
639
640         free(to_free);
641         return 1;
642 }
643
644 static enum crlf_action git_path_check_crlf(const char *path, struct git_attr_check *check)
645 {
646         const char *value = check->value;
647
648         if (ATTR_TRUE(value))
649                 return CRLF_TEXT;
650         else if (ATTR_FALSE(value))
651                 return CRLF_BINARY;
652         else if (ATTR_UNSET(value))
653                 ;
654         else if (!strcmp(value, "input"))
655                 return CRLF_INPUT;
656         else if (!strcmp(value, "auto"))
657                 return CRLF_AUTO;
658         return CRLF_GUESS;
659 }
660
661 static enum eol git_path_check_eol(const char *path, struct git_attr_check *check)
662 {
663         const char *value = check->value;
664
665         if (ATTR_UNSET(value))
666                 ;
667         else if (!strcmp(value, "lf"))
668                 return EOL_LF;
669         else if (!strcmp(value, "crlf"))
670                 return EOL_CRLF;
671         return EOL_UNSET;
672 }
673
674 static struct convert_driver *git_path_check_convert(const char *path,
675                                              struct git_attr_check *check)
676 {
677         const char *value = check->value;
678         struct convert_driver *drv;
679
680         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
681                 return NULL;
682         for (drv = user_convert; drv; drv = drv->next)
683                 if (!strcmp(value, drv->name))
684                         return drv;
685         return NULL;
686 }
687
688 static int git_path_check_ident(const char *path, struct git_attr_check *check)
689 {
690         const char *value = check->value;
691
692         return !!ATTR_TRUE(value);
693 }
694
695 static enum crlf_action input_crlf_action(enum crlf_action text_attr, enum eol eol_attr)
696 {
697         if (text_attr == CRLF_BINARY)
698                 return CRLF_BINARY;
699         if (eol_attr == EOL_LF)
700                 return CRLF_INPUT;
701         if (eol_attr == EOL_CRLF)
702                 return CRLF_CRLF;
703         return text_attr;
704 }
705
706 struct conv_attrs {
707         struct convert_driver *drv;
708         enum crlf_action crlf_action;
709         enum eol eol_attr;
710         int ident;
711 };
712
713 static const char *conv_attr_name[] = {
714         "crlf", "ident", "filter", "eol", "text",
715 };
716 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
717
718 static void convert_attrs(struct conv_attrs *ca, const char *path)
719 {
720         int i;
721         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
722
723         if (!ccheck[0].attr) {
724                 for (i = 0; i < NUM_CONV_ATTRS; i++)
725                         ccheck[i].attr = git_attr(conv_attr_name[i]);
726                 user_convert_tail = &user_convert;
727                 git_config(read_convert_config, NULL);
728         }
729
730         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
731                 ca->crlf_action = git_path_check_crlf(path, ccheck + 4);
732                 if (ca->crlf_action == CRLF_GUESS)
733                         ca->crlf_action = git_path_check_crlf(path, ccheck + 0);
734                 ca->ident = git_path_check_ident(path, ccheck + 1);
735                 ca->drv = git_path_check_convert(path, ccheck + 2);
736                 ca->eol_attr = git_path_check_eol(path, ccheck + 3);
737         } else {
738                 ca->drv = NULL;
739                 ca->crlf_action = CRLF_GUESS;
740                 ca->eol_attr = EOL_UNSET;
741                 ca->ident = 0;
742         }
743 }
744
745 int convert_to_git(const char *path, const char *src, size_t len,
746                    struct strbuf *dst, enum safe_crlf checksafe)
747 {
748         int ret = 0;
749         const char *filter = NULL;
750         struct conv_attrs ca;
751
752         convert_attrs(&ca, path);
753         if (ca.drv)
754                 filter = ca.drv->clean;
755
756         ret |= apply_filter(path, src, len, dst, filter);
757         if (ret) {
758                 src = dst->buf;
759                 len = dst->len;
760         }
761         ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
762         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
763         if (ret) {
764                 src = dst->buf;
765                 len = dst->len;
766         }
767         return ret | ident_to_git(path, src, len, dst, ca.ident);
768 }
769
770 static int convert_to_working_tree_internal(const char *path, const char *src,
771                                             size_t len, struct strbuf *dst,
772                                             int normalizing)
773 {
774         int ret = 0;
775         const char *filter = NULL;
776         struct conv_attrs ca;
777
778         convert_attrs(&ca, path);
779         if (ca.drv)
780                 filter = ca.drv->smudge;
781
782         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
783         if (ret) {
784                 src = dst->buf;
785                 len = dst->len;
786         }
787         /*
788          * CRLF conversion can be skipped if normalizing, unless there
789          * is a smudge filter.  The filter might expect CRLFs.
790          */
791         if (filter || !normalizing) {
792                 ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
793                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
794                 if (ret) {
795                         src = dst->buf;
796                         len = dst->len;
797                 }
798         }
799         return ret | apply_filter(path, src, len, dst, filter);
800 }
801
802 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
803 {
804         return convert_to_working_tree_internal(path, src, len, dst, 0);
805 }
806
807 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
808 {
809         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
810         if (ret) {
811                 src = dst->buf;
812                 len = dst->len;
813         }
814         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
815 }
816
817 /*****************************************************************
818  *
819  * Streaming converison support
820  *
821  *****************************************************************/
822
823 typedef int (*filter_fn)(struct stream_filter *,
824                          const char *input, size_t *isize_p,
825                          char *output, size_t *osize_p);
826 typedef void (*free_fn)(struct stream_filter *);
827
828 struct stream_filter_vtbl {
829         filter_fn filter;
830         free_fn free;
831 };
832
833 struct stream_filter {
834         struct stream_filter_vtbl *vtbl;
835 };
836
837 static int null_filter_fn(struct stream_filter *filter,
838                           const char *input, size_t *isize_p,
839                           char *output, size_t *osize_p)
840 {
841         size_t count;
842
843         if (!input)
844                 return 0; /* we do not keep any states */
845         count = *isize_p;
846         if (*osize_p < count)
847                 count = *osize_p;
848         if (count) {
849                 memmove(output, input, count);
850                 *isize_p -= count;
851                 *osize_p -= count;
852         }
853         return 0;
854 }
855
856 static void null_free_fn(struct stream_filter *filter)
857 {
858         ; /* nothing -- null instances are shared */
859 }
860
861 static struct stream_filter_vtbl null_vtbl = {
862         null_filter_fn,
863         null_free_fn,
864 };
865
866 static struct stream_filter null_filter_singleton = {
867         &null_vtbl,
868 };
869
870 int is_null_stream_filter(struct stream_filter *filter)
871 {
872         return filter == &null_filter_singleton;
873 }
874
875
876 /*
877  * LF-to-CRLF filter
878  */
879
880 struct lf_to_crlf_filter {
881         struct stream_filter filter;
882         unsigned has_held:1;
883         char held;
884 };
885
886 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
887                                 const char *input, size_t *isize_p,
888                                 char *output, size_t *osize_p)
889 {
890         size_t count, o = 0;
891         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
892
893         /*
894          * We may be holding onto the CR to see if it is followed by a
895          * LF, in which case we would need to go to the main loop.
896          * Otherwise, just emit it to the output stream.
897          */
898         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
899                 output[o++] = lf_to_crlf->held;
900                 lf_to_crlf->has_held = 0;
901         }
902
903         /* We are told to drain */
904         if (!input) {
905                 *osize_p -= o;
906                 return 0;
907         }
908
909         count = *isize_p;
910         if (count || lf_to_crlf->has_held) {
911                 size_t i;
912                 int was_cr = 0;
913
914                 if (lf_to_crlf->has_held) {
915                         was_cr = 1;
916                         lf_to_crlf->has_held = 0;
917                 }
918
919                 for (i = 0; o < *osize_p && i < count; i++) {
920                         char ch = input[i];
921
922                         if (ch == '\n') {
923                                 output[o++] = '\r';
924                         } else if (was_cr) {
925                                 /*
926                                  * Previous round saw CR and it is not followed
927                                  * by a LF; emit the CR before processing the
928                                  * current character.
929                                  */
930                                 output[o++] = '\r';
931                         }
932
933                         /*
934                          * We may have consumed the last output slot,
935                          * in which case we need to break out of this
936                          * loop; hold the current character before
937                          * returning.
938                          */
939                         if (*osize_p <= o) {
940                                 lf_to_crlf->has_held = 1;
941                                 lf_to_crlf->held = ch;
942                                 continue; /* break but increment i */
943                         }
944
945                         if (ch == '\r') {
946                                 was_cr = 1;
947                                 continue;
948                         }
949
950                         was_cr = 0;
951                         output[o++] = ch;
952                 }
953
954                 *osize_p -= o;
955                 *isize_p -= i;
956
957                 if (!lf_to_crlf->has_held && was_cr) {
958                         lf_to_crlf->has_held = 1;
959                         lf_to_crlf->held = '\r';
960                 }
961         }
962         return 0;
963 }
964
965 static void lf_to_crlf_free_fn(struct stream_filter *filter)
966 {
967         free(filter);
968 }
969
970 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
971         lf_to_crlf_filter_fn,
972         lf_to_crlf_free_fn,
973 };
974
975 static struct stream_filter *lf_to_crlf_filter(void)
976 {
977         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
978
979         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
980         return (struct stream_filter *)lf_to_crlf;
981 }
982
983 /*
984  * Cascade filter
985  */
986 #define FILTER_BUFFER 1024
987 struct cascade_filter {
988         struct stream_filter filter;
989         struct stream_filter *one;
990         struct stream_filter *two;
991         char buf[FILTER_BUFFER];
992         int end, ptr;
993 };
994
995 static int cascade_filter_fn(struct stream_filter *filter,
996                              const char *input, size_t *isize_p,
997                              char *output, size_t *osize_p)
998 {
999         struct cascade_filter *cas = (struct cascade_filter *) filter;
1000         size_t filled = 0;
1001         size_t sz = *osize_p;
1002         size_t to_feed, remaining;
1003
1004         /*
1005          * input -- (one) --> buf -- (two) --> output
1006          */
1007         while (filled < sz) {
1008                 remaining = sz - filled;
1009
1010                 /* do we already have something to feed two with? */
1011                 if (cas->ptr < cas->end) {
1012                         to_feed = cas->end - cas->ptr;
1013                         if (stream_filter(cas->two,
1014                                           cas->buf + cas->ptr, &to_feed,
1015                                           output + filled, &remaining))
1016                                 return -1;
1017                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1018                         filled = sz - remaining;
1019                         continue;
1020                 }
1021
1022                 /* feed one from upstream and have it emit into our buffer */
1023                 to_feed = input ? *isize_p : 0;
1024                 if (input && !to_feed)
1025                         break;
1026                 remaining = sizeof(cas->buf);
1027                 if (stream_filter(cas->one,
1028                                   input, &to_feed,
1029                                   cas->buf, &remaining))
1030                         return -1;
1031                 cas->end = sizeof(cas->buf) - remaining;
1032                 cas->ptr = 0;
1033                 if (input) {
1034                         size_t fed = *isize_p - to_feed;
1035                         *isize_p -= fed;
1036                         input += fed;
1037                 }
1038
1039                 /* do we know that we drained one completely? */
1040                 if (input || cas->end)
1041                         continue;
1042
1043                 /* tell two to drain; we have nothing more to give it */
1044                 to_feed = 0;
1045                 remaining = sz - filled;
1046                 if (stream_filter(cas->two,
1047                                   NULL, &to_feed,
1048                                   output + filled, &remaining))
1049                         return -1;
1050                 if (remaining == (sz - filled))
1051                         break; /* completely drained two */
1052                 filled = sz - remaining;
1053         }
1054         *osize_p -= filled;
1055         return 0;
1056 }
1057
1058 static void cascade_free_fn(struct stream_filter *filter)
1059 {
1060         struct cascade_filter *cas = (struct cascade_filter *)filter;
1061         free_stream_filter(cas->one);
1062         free_stream_filter(cas->two);
1063         free(filter);
1064 }
1065
1066 static struct stream_filter_vtbl cascade_vtbl = {
1067         cascade_filter_fn,
1068         cascade_free_fn,
1069 };
1070
1071 static struct stream_filter *cascade_filter(struct stream_filter *one,
1072                                             struct stream_filter *two)
1073 {
1074         struct cascade_filter *cascade;
1075
1076         if (!one || is_null_stream_filter(one))
1077                 return two;
1078         if (!two || is_null_stream_filter(two))
1079                 return one;
1080
1081         cascade = xmalloc(sizeof(*cascade));
1082         cascade->one = one;
1083         cascade->two = two;
1084         cascade->end = cascade->ptr = 0;
1085         cascade->filter.vtbl = &cascade_vtbl;
1086         return (struct stream_filter *)cascade;
1087 }
1088
1089 /*
1090  * ident filter
1091  */
1092 #define IDENT_DRAINING (-1)
1093 #define IDENT_SKIPPING (-2)
1094 struct ident_filter {
1095         struct stream_filter filter;
1096         struct strbuf left;
1097         int state;
1098         char ident[45]; /* ": x40 $" */
1099 };
1100
1101 static int is_foreign_ident(const char *str)
1102 {
1103         int i;
1104
1105         if (prefixcmp(str, "$Id: "))
1106                 return 0;
1107         for (i = 5; str[i]; i++) {
1108                 if (isspace(str[i]) && str[i+1] != '$')
1109                         return 1;
1110         }
1111         return 0;
1112 }
1113
1114 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1115 {
1116         size_t to_drain = ident->left.len;
1117
1118         if (*osize_p < to_drain)
1119                 to_drain = *osize_p;
1120         if (to_drain) {
1121                 memcpy(*output_p, ident->left.buf, to_drain);
1122                 strbuf_remove(&ident->left, 0, to_drain);
1123                 *output_p += to_drain;
1124                 *osize_p -= to_drain;
1125         }
1126         if (!ident->left.len)
1127                 ident->state = 0;
1128 }
1129
1130 static int ident_filter_fn(struct stream_filter *filter,
1131                            const char *input, size_t *isize_p,
1132                            char *output, size_t *osize_p)
1133 {
1134         struct ident_filter *ident = (struct ident_filter *)filter;
1135         static const char head[] = "$Id";
1136
1137         if (!input) {
1138                 /* drain upon eof */
1139                 switch (ident->state) {
1140                 default:
1141                         strbuf_add(&ident->left, head, ident->state);
1142                 case IDENT_SKIPPING:
1143                         /* fallthru */
1144                 case IDENT_DRAINING:
1145                         ident_drain(ident, &output, osize_p);
1146                 }
1147                 return 0;
1148         }
1149
1150         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1151                 int ch;
1152
1153                 if (ident->state == IDENT_DRAINING) {
1154                         ident_drain(ident, &output, osize_p);
1155                         if (!*osize_p)
1156                                 break;
1157                         continue;
1158                 }
1159
1160                 ch = *(input++);
1161                 (*isize_p)--;
1162
1163                 if (ident->state == IDENT_SKIPPING) {
1164                         /*
1165                          * Skipping until '$' or LF, but keeping them
1166                          * in case it is a foreign ident.
1167                          */
1168                         strbuf_addch(&ident->left, ch);
1169                         if (ch != '\n' && ch != '$')
1170                                 continue;
1171                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1172                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1173                                 strbuf_addstr(&ident->left, ident->ident);
1174                         }
1175                         ident->state = IDENT_DRAINING;
1176                         continue;
1177                 }
1178
1179                 if (ident->state < sizeof(head) &&
1180                     head[ident->state] == ch) {
1181                         ident->state++;
1182                         continue;
1183                 }
1184
1185                 if (ident->state)
1186                         strbuf_add(&ident->left, head, ident->state);
1187                 if (ident->state == sizeof(head) - 1) {
1188                         if (ch != ':' && ch != '$') {
1189                                 strbuf_addch(&ident->left, ch);
1190                                 ident->state = 0;
1191                                 continue;
1192                         }
1193
1194                         if (ch == ':') {
1195                                 strbuf_addch(&ident->left, ch);
1196                                 ident->state = IDENT_SKIPPING;
1197                         } else {
1198                                 strbuf_addstr(&ident->left, ident->ident);
1199                                 ident->state = IDENT_DRAINING;
1200                         }
1201                         continue;
1202                 }
1203
1204                 strbuf_addch(&ident->left, ch);
1205                 ident->state = IDENT_DRAINING;
1206         }
1207         return 0;
1208 }
1209
1210 static void ident_free_fn(struct stream_filter *filter)
1211 {
1212         struct ident_filter *ident = (struct ident_filter *)filter;
1213         strbuf_release(&ident->left);
1214         free(filter);
1215 }
1216
1217 static struct stream_filter_vtbl ident_vtbl = {
1218         ident_filter_fn,
1219         ident_free_fn,
1220 };
1221
1222 static struct stream_filter *ident_filter(const unsigned char *sha1)
1223 {
1224         struct ident_filter *ident = xmalloc(sizeof(*ident));
1225
1226         sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
1227         strbuf_init(&ident->left, 0);
1228         ident->filter.vtbl = &ident_vtbl;
1229         ident->state = 0;
1230         return (struct stream_filter *)ident;
1231 }
1232
1233 /*
1234  * Return an appropriately constructed filter for the path, or NULL if
1235  * the contents cannot be filtered without reading the whole thing
1236  * in-core.
1237  *
1238  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1239  * large binary blob you would want us not to slurp into the memory!
1240  */
1241 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1242 {
1243         struct conv_attrs ca;
1244         enum crlf_action crlf_action;
1245         struct stream_filter *filter = NULL;
1246
1247         convert_attrs(&ca, path);
1248
1249         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1250                 return filter;
1251
1252         if (ca.ident)
1253                 filter = ident_filter(sha1);
1254
1255         crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
1256
1257         if ((crlf_action == CRLF_BINARY) || (crlf_action == CRLF_INPUT) ||
1258             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
1259                 filter = cascade_filter(filter, &null_filter_singleton);
1260
1261         else if (output_eol(crlf_action) == EOL_CRLF &&
1262                  !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
1263                 filter = cascade_filter(filter, lf_to_crlf_filter());
1264
1265         return filter;
1266 }
1267
1268 void free_stream_filter(struct stream_filter *filter)
1269 {
1270         filter->vtbl->free(filter);
1271 }
1272
1273 int stream_filter(struct stream_filter *filter,
1274                   const char *input, size_t *isize_p,
1275                   char *output, size_t *osize_p)
1276 {
1277         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1278 }