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