1#include "cache.h"
2#include "attr.h"
3#include "run-command.h"
4/*
6 * convert.c - convert a file when checking it out and checking it in.
7 *
8 * This should use the pathname to decide on whether it wants to do some
9 * more interesting conversions (automatic gzip/unzip, general format
10 * conversions etc etc), but by default it just does automatic CRLF<->LF
11 * translation when the "auto_crlf" option is set.
12 */
13#define CRLF_GUESS (-1)
15#define CRLF_BINARY 0
16#define CRLF_TEXT 1
17#define CRLF_INPUT 2
18struct text_stat {
20 /* NUL, CR, LF and CRLF counts */
21 unsigned nul, cr, lf, crlf;
22 /* These are just approximations! */
24 unsigned printable, nonprintable;
25};
26static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
28{
29 unsigned long i;
30 memset(stats, 0, sizeof(*stats));
32 for (i = 0; i < size; i++) {
34 unsigned char c = buf[i];
35 if (c == '\r') {
36 stats->cr++;
37 if (i+1 < size && buf[i+1] == '\n')
38 stats->crlf++;
39 continue;
40 }
41 if (c == '\n') {
42 stats->lf++;
43 continue;
44 }
45 if (c == 127)
46 /* DEL */
47 stats->nonprintable++;
48 else if (c < 32) {
49 switch (c) {
50 /* BS, HT, ESC and FF */
51 case '\b': case '\t': case '\033': case '\014':
52 stats->printable++;
53 break;
54 case 0:
55 stats->nul++;
56 /* fall through */
57 default:
58 stats->nonprintable++;
59 }
60 }
61 else
62 stats->printable++;
63 }
64}
65/*
67 * The same heuristics as diff.c::mmfile_is_binary()
68 */
69static int is_binary(unsigned long size, struct text_stat *stats)
70{
71 if (stats->nul)
73 return 1;
74 if ((stats->printable >> 7) < stats->nonprintable)
75 return 1;
76 /*
77 * Other heuristics? Average line length might be relevant,
78 * as might LF vs CR vs CRLF counts..
79 *
80 * NOTE! It might be normal to have a low ratio of CRLF to LF
81 * (somebody starts with a LF-only file and edits it with an editor
82 * that adds CRLF only to lines that are added..). But do we
83 * want to support CR-only? Probably not.
84 */
85 return 0;
86}
87static void check_safe_crlf(const char *path, int action,
89 struct text_stat *stats, enum safe_crlf checksafe)
90{
91 if (!checksafe)
92 return;
93 if (action == CRLF_INPUT || auto_crlf <= 0) {
95 /*
96 * CRLFs would not be restored by checkout:
97 * check if we'd remove CRLFs
98 */
99 if (stats->crlf) {
100 if (checksafe == SAFE_CRLF_WARN)
101 warning("CRLF will be replaced by LF in %s.", path);
102 else /* i.e. SAFE_CRLF_FAIL */
103 die("CRLF would be replaced by LF in %s.", path);
104 }
105 } else if (auto_crlf > 0) {
106 /*
107 * CRLFs would be added by checkout:
108 * check if we have "naked" LFs
109 */
110 if (stats->lf != stats->crlf) {
111 if (checksafe == SAFE_CRLF_WARN)
112 warning("LF will be replaced by CRLF in %s", path);
113 else /* i.e. SAFE_CRLF_FAIL */
114 die("LF would be replaced by CRLF in %s", path);
115 }
116 }
117}
118static int crlf_to_git(const char *path, const char *src, size_t len,
120 struct strbuf *buf, int action, enum safe_crlf checksafe)
121{
122 struct text_stat stats;
123 char *dst;
124 if ((action == CRLF_BINARY) || !auto_crlf || !len)
126 return 0;
127 gather_stats(src, len, &stats);
129 if (action == CRLF_GUESS) {
131 /*
132 * We're currently not going to even try to convert stuff
133 * that has bare CR characters. Does anybody do that crazy
134 * stuff?
135 */
136 if (stats.cr != stats.crlf)
137 return 0;
138 /*
140 * And add some heuristics for binary vs text, of course...
141 */
142 if (is_binary(len, &stats))
143 return 0;
144 }
145 check_safe_crlf(path, action, &stats, checksafe);
147 /* Optimization: No CR? Nothing to convert, regardless. */
149 if (!stats.cr)
150 return 0;
151 /* only grow if not in place */
153 if (strbuf_avail(buf) + buf->len < len)
154 strbuf_grow(buf, len - buf->len);
155 dst = buf->buf;
156 if (action == CRLF_GUESS) {
157 /*
158 * If we guessed, we already know we rejected a file with
159 * lone CR, and we can strip a CR without looking at what
160 * follow it.
161 */
162 do {
163 unsigned char c = *src++;
164 if (c != '\r')
165 *dst++ = c;
166 } while (--len);
167 } else {
168 do {
169 unsigned char c = *src++;
170 if (! (c == '\r' && (1 < len && *src == '\n')))
171 *dst++ = c;
172 } while (--len);
173 }
174 strbuf_setlen(buf, dst - buf->buf);
175 return 1;
176}
177static int crlf_to_worktree(const char *path, const char *src, size_t len,
179 struct strbuf *buf, int action)
180{
181 char *to_free = NULL;
182 struct text_stat stats;
183 if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
185 auto_crlf <= 0)
186 return 0;
187 if (!len)
189 return 0;
190 gather_stats(src, len, &stats);
192 /* No LF? Nothing to convert, regardless. */
194 if (!stats.lf)
195 return 0;
196 /* Was it already in CRLF format? */
198 if (stats.lf == stats.crlf)
199 return 0;
200 if (action == CRLF_GUESS) {
202 /* If we have any bare CR characters, we're not going to touch it */
203 if (stats.cr != stats.crlf)
204 return 0;
205 if (is_binary(len, &stats))
207 return 0;
208 }
209 /* are we "faking" in place editing ? */
211 if (src == buf->buf)
212 to_free = strbuf_detach(buf, NULL);
213 strbuf_grow(buf, len + stats.lf - stats.crlf);
215 for (;;) {
216 const char *nl = memchr(src, '\n', len);
217 if (!nl)
218 break;
219 if (nl > src && nl[-1] == '\r') {
220 strbuf_add(buf, src, nl + 1 - src);
221 } else {
222 strbuf_add(buf, src, nl - src);
223 strbuf_addstr(buf, "\r\n");
224 }
225 len -= nl + 1 - src;
226 src = nl + 1;
227 }
228 strbuf_add(buf, src, len);
229 free(to_free);
231 return 1;
232}
233struct filter_params {
235 const char *src;
236 unsigned long size;
237 const char *cmd;
238};
239static int filter_buffer(int fd, void *data)
241{
242 /*
243 * Spawn cmd and feed the buffer contents through its stdin.
244 */
245 struct child_process child_process;
246 struct filter_params *params = (struct filter_params *)data;
247 int write_err, status;
248 const char *argv[] = { "sh", "-c", params->cmd, NULL };
249 memset(&child_process, 0, sizeof(child_process));
251 child_process.argv = argv;
252 child_process.in = -1;
253 child_process.out = fd;
254 if (start_command(&child_process))
256 return error("cannot fork to run external filter %s", params->cmd);
257 write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
259 if (close(child_process.in))
260 write_err = 1;
261 if (write_err)
262 error("cannot feed the input to external filter %s", params->cmd);
263 status = finish_command(&child_process);
265 if (status)
266 error("external filter %s failed %d", params->cmd, -status);
267 return (write_err || status);
268}
269static int apply_filter(const char *path, const char *src, size_t len,
271 struct strbuf *dst, const char *cmd)
272{
273 /*
274 * Create a pipeline to have the command filter the buffer's
275 * contents.
276 *
277 * (child --> cmd) --> us
278 */
279 int ret = 1;
280 struct strbuf nbuf;
281 struct async async;
282 struct filter_params params;
283 if (!cmd)
285 return 0;
286 memset(&async, 0, sizeof(async));
288 async.proc = filter_buffer;
289 async.data = ¶ms;
290 params.src = src;
291 params.size = len;
292 params.cmd = cmd;
293 fflush(NULL);
295 if (start_async(&async))
296 return 0; /* error was already reported */
297 strbuf_init(&nbuf, 0);
299 if (strbuf_read(&nbuf, async.out, len) < 0) {
300 error("read from external filter %s failed", cmd);
301 ret = 0;
302 }
303 if (close(async.out)) {
304 error("read from external filter %s failed", cmd);
305 ret = 0;
306 }
307 if (finish_async(&async)) {
308 error("external filter %s failed", cmd);
309 ret = 0;
310 }
311 if (ret) {
313 strbuf_swap(dst, &nbuf);
314 }
315 strbuf_release(&nbuf);
316 return ret;
317}
318static struct convert_driver {
320 const char *name;
321 struct convert_driver *next;
322 char *smudge;
323 char *clean;
324} *user_convert, **user_convert_tail;
325static int read_convert_config(const char *var, const char *value)
327{
328 const char *ep, *name;
329 int namelen;
330 struct convert_driver *drv;
331 /*
333 * External conversion drivers are configured using
334 * "filter.<name>.variable".
335 */
336 if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
337 return 0;
338 name = var + 7;
339 namelen = ep - name;
340 for (drv = user_convert; drv; drv = drv->next)
341 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
342 break;
343 if (!drv) {
344 drv = xcalloc(1, sizeof(struct convert_driver));
345 drv->name = xmemdupz(name, namelen);
346 *user_convert_tail = drv;
347 user_convert_tail = &(drv->next);
348 }
349 ep++;
351 /*
353 * filter.<name>.smudge and filter.<name>.clean specifies
354 * the command line:
355 *
356 * command-line
357 *
358 * The command-line will not be interpolated in any way.
359 */
360 if (!strcmp("smudge", ep)) {
362 if (!value)
363 return config_error_nonbool(var);
364 drv->smudge = strdup(value);
365 return 0;
366 }
367 if (!strcmp("clean", ep)) {
369 if (!value)
370 return config_error_nonbool(var);
371 drv->clean = strdup(value);
372 return 0;
373 }
374 return 0;
375}
376static void setup_convert_check(struct git_attr_check *check)
378{
379 static struct git_attr *attr_crlf;
380 static struct git_attr *attr_ident;
381 static struct git_attr *attr_filter;
382 if (!attr_crlf) {
384 attr_crlf = git_attr("crlf", 4);
385 attr_ident = git_attr("ident", 5);
386 attr_filter = git_attr("filter", 6);
387 user_convert_tail = &user_convert;
388 git_config(read_convert_config);
389 }
390 check[0].attr = attr_crlf;
391 check[1].attr = attr_ident;
392 check[2].attr = attr_filter;
393}
394static int count_ident(const char *cp, unsigned long size)
396{
397 /*
398 * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
399 */
400 int cnt = 0;
401 char ch;
402 while (size) {
404 ch = *cp++;
405 size--;
406 if (ch != '$')
407 continue;
408 if (size < 3)
409 break;
410 if (memcmp("Id", cp, 2))
411 continue;
412 ch = cp[2];
413 cp += 3;
414 size -= 3;
415 if (ch == '$')
416 cnt++; /* $Id$ */
417 if (ch != ':')
418 continue;
419 /*
421 * "$Id: ... "; scan up to the closing dollar sign and discard.
422 */
423 while (size) {
424 ch = *cp++;
425 size--;
426 if (ch == '$') {
427 cnt++;
428 break;
429 }
430 }
431 }
432 return cnt;
433}
434static int ident_to_git(const char *path, const char *src, size_t len,
436 struct strbuf *buf, int ident)
437{
438 char *dst, *dollar;
439 if (!ident || !count_ident(src, len))
441 return 0;
442 /* only grow if not in place */
444 if (strbuf_avail(buf) + buf->len < len)
445 strbuf_grow(buf, len - buf->len);
446 dst = buf->buf;
447 for (;;) {
448 dollar = memchr(src, '$', len);
449 if (!dollar)
450 break;
451 memcpy(dst, src, dollar + 1 - src);
452 dst += dollar + 1 - src;
453 len -= dollar + 1 - src;
454 src = dollar + 1;
455 if (len > 3 && !memcmp(src, "Id:", 3)) {
457 dollar = memchr(src + 3, '$', len - 3);
458 if (!dollar)
459 break;
460 memcpy(dst, "Id$", 3);
461 dst += 3;
462 len -= dollar + 1 - src;
463 src = dollar + 1;
464 }
465 }
466 memcpy(dst, src, len);
467 strbuf_setlen(buf, dst + len - buf->buf);
468 return 1;
469}
470static int ident_to_worktree(const char *path, const char *src, size_t len,
472 struct strbuf *buf, int ident)
473{
474 unsigned char sha1[20];
475 char *to_free = NULL, *dollar;
476 int cnt;
477 if (!ident)
479 return 0;
480 cnt = count_ident(src, len);
482 if (!cnt)
483 return 0;
484 /* are we "faking" in place editing ? */
486 if (src == buf->buf)
487 to_free = strbuf_detach(buf, NULL);
488 hash_sha1_file(src, len, "blob", sha1);
489 strbuf_grow(buf, len + cnt * 43);
491 for (;;) {
492 /* step 1: run to the next '$' */
493 dollar = memchr(src, '$', len);
494 if (!dollar)
495 break;
496 strbuf_add(buf, src, dollar + 1 - src);
497 len -= dollar + 1 - src;
498 src = dollar + 1;
499 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
501 if (len < 3 || memcmp("Id", src, 2))
502 continue;
503 /* step 3: skip over Id$ or Id:xxxxx$ */
505 if (src[2] == '$') {
506 src += 3;
507 len -= 3;
508 } else if (src[2] == ':') {
509 /*
510 * It's possible that an expanded Id has crept its way into the
511 * repository, we cope with that by stripping the expansion out
512 */
513 dollar = memchr(src + 3, '$', len - 3);
514 if (!dollar) {
515 /* incomplete keyword, no more '$', so just quit the loop */
516 break;
517 }
518 len -= dollar + 1 - src;
520 src = dollar + 1;
521 } else {
522 /* it wasn't a "Id$" or "Id:xxxx$" */
523 continue;
524 }
525 /* step 4: substitute */
527 strbuf_addstr(buf, "Id: ");
528 strbuf_add(buf, sha1_to_hex(sha1), 40);
529 strbuf_addstr(buf, " $");
530 }
531 strbuf_add(buf, src, len);
532 free(to_free);
534 return 1;
535}
536static int git_path_check_crlf(const char *path, struct git_attr_check *check)
538{
539 const char *value = check->value;
540 if (ATTR_TRUE(value))
542 return CRLF_TEXT;
543 else if (ATTR_FALSE(value))
544 return CRLF_BINARY;
545 else if (ATTR_UNSET(value))
546 ;
547 else if (!strcmp(value, "input"))
548 return CRLF_INPUT;
549 return CRLF_GUESS;
550}
551static struct convert_driver *git_path_check_convert(const char *path,
553 struct git_attr_check *check)
554{
555 const char *value = check->value;
556 struct convert_driver *drv;
557 if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
559 return NULL;
560 for (drv = user_convert; drv; drv = drv->next)
561 if (!strcmp(value, drv->name))
562 return drv;
563 return NULL;
564}
565static int git_path_check_ident(const char *path, struct git_attr_check *check)
567{
568 const char *value = check->value;
569 return !!ATTR_TRUE(value);
571}
572int convert_to_git(const char *path, const char *src, size_t len,
574 struct strbuf *dst, enum safe_crlf checksafe)
575{
576 struct git_attr_check check[3];
577 int crlf = CRLF_GUESS;
578 int ident = 0, ret = 0;
579 char *filter = NULL;
580 setup_convert_check(check);
582 if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
583 struct convert_driver *drv;
584 crlf = git_path_check_crlf(path, check + 0);
585 ident = git_path_check_ident(path, check + 1);
586 drv = git_path_check_convert(path, check + 2);
587 if (drv && drv->clean)
588 filter = drv->clean;
589 }
590 ret |= apply_filter(path, src, len, dst, filter);
592 if (ret) {
593 src = dst->buf;
594 len = dst->len;
595 }
596 ret |= crlf_to_git(path, src, len, dst, crlf, checksafe);
597 if (ret) {
598 src = dst->buf;
599 len = dst->len;
600 }
601 return ret | ident_to_git(path, src, len, dst, ident);
602}
603int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
605{
606 struct git_attr_check check[3];
607 int crlf = CRLF_GUESS;
608 int ident = 0, ret = 0;
609 char *filter = NULL;
610 setup_convert_check(check);
612 if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
613 struct convert_driver *drv;
614 crlf = git_path_check_crlf(path, check + 0);
615 ident = git_path_check_ident(path, check + 1);
616 drv = git_path_check_convert(path, check + 2);
617 if (drv && drv->smudge)
618 filter = drv->smudge;
619 }
620 ret |= ident_to_worktree(path, src, len, dst, ident);
622 if (ret) {
623 src = dst->buf;
624 len = dst->len;
625 }
626 ret |= crlf_to_worktree(path, src, len, dst, crlf);
627 if (ret) {
628 src = dst->buf;
629 len = dst->len;
630 }
631 return ret | apply_filter(path, src, len, dst, filter);
632}