Merge branch 'jk/maint-null-in-trees'
[alt-git.git] / attr.c
blobb52efb55a036be10618d531d66697d7f7220c524
1 /*
2 * Handle git attributes. See gitattributes(5) for a description of
3 * the file syntax, and Documentation/technical/api-gitattributes.txt
4 * for a description of the API.
6 * One basic design decision here is that we are not going to support
7 * an insanely large number of attributes.
8 */
10 #define NO_THE_INDEX_COMPATIBILITY_MACROS
11 #include "cache.h"
12 #include "exec_cmd.h"
13 #include "attr.h"
14 #include "dir.h"
16 const char git_attr__true[] = "(builtin)true";
17 const char git_attr__false[] = "\0(builtin)false";
18 static const char git_attr__unknown[] = "(builtin)unknown";
19 #define ATTR__TRUE git_attr__true
20 #define ATTR__FALSE git_attr__false
21 #define ATTR__UNSET NULL
22 #define ATTR__UNKNOWN git_attr__unknown
24 /* This is a randomly chosen prime. */
25 #define HASHSIZE 257
27 #ifndef DEBUG_ATTR
28 #define DEBUG_ATTR 0
29 #endif
31 struct git_attr {
32 struct git_attr *next;
33 unsigned h;
34 int attr_nr;
35 char name[FLEX_ARRAY];
37 static int attr_nr;
39 static struct git_attr_check *check_all_attr;
40 static struct git_attr *(git_attr_hash[HASHSIZE]);
42 char *git_attr_name(struct git_attr *attr)
44 return attr->name;
47 static unsigned hash_name(const char *name, int namelen)
49 unsigned val = 0, c;
51 while (namelen--) {
52 c = *name++;
53 val = ((val << 7) | (val >> 22)) ^ c;
55 return val;
58 static int invalid_attr_name(const char *name, int namelen)
61 * Attribute name cannot begin with '-' and must consist of
62 * characters from [-A-Za-z0-9_.].
64 if (namelen <= 0 || *name == '-')
65 return -1;
66 while (namelen--) {
67 char ch = *name++;
68 if (! (ch == '-' || ch == '.' || ch == '_' ||
69 ('0' <= ch && ch <= '9') ||
70 ('a' <= ch && ch <= 'z') ||
71 ('A' <= ch && ch <= 'Z')) )
72 return -1;
74 return 0;
77 static struct git_attr *git_attr_internal(const char *name, int len)
79 unsigned hval = hash_name(name, len);
80 unsigned pos = hval % HASHSIZE;
81 struct git_attr *a;
83 for (a = git_attr_hash[pos]; a; a = a->next) {
84 if (a->h == hval &&
85 !memcmp(a->name, name, len) && !a->name[len])
86 return a;
89 if (invalid_attr_name(name, len))
90 return NULL;
92 a = xmalloc(sizeof(*a) + len + 1);
93 memcpy(a->name, name, len);
94 a->name[len] = 0;
95 a->h = hval;
96 a->next = git_attr_hash[pos];
97 a->attr_nr = attr_nr++;
98 git_attr_hash[pos] = a;
100 check_all_attr = xrealloc(check_all_attr,
101 sizeof(*check_all_attr) * attr_nr);
102 check_all_attr[a->attr_nr].attr = a;
103 check_all_attr[a->attr_nr].value = ATTR__UNKNOWN;
104 return a;
107 struct git_attr *git_attr(const char *name)
109 return git_attr_internal(name, strlen(name));
112 /* What does a matched pattern decide? */
113 struct attr_state {
114 struct git_attr *attr;
115 const char *setto;
119 * One rule, as from a .gitattributes file.
121 * If is_macro is true, then u.attr is a pointer to the git_attr being
122 * defined.
124 * If is_macro is false, then u.pattern points at the filename pattern
125 * to which the rule applies. (The memory pointed to is part of the
126 * memory block allocated for the match_attr instance.)
128 * In either case, num_attr is the number of attributes affected by
129 * this rule, and state is an array listing them. The attributes are
130 * listed as they appear in the file (macros unexpanded).
132 struct match_attr {
133 union {
134 char *pattern;
135 struct git_attr *attr;
136 } u;
137 char is_macro;
138 unsigned num_attr;
139 struct attr_state state[FLEX_ARRAY];
142 static const char blank[] = " \t\r\n";
145 * Parse a whitespace-delimited attribute state (i.e., "attr",
146 * "-attr", "!attr", or "attr=value") from the string starting at src.
147 * If e is not NULL, write the results to *e. Return a pointer to the
148 * remainder of the string (with leading whitespace removed), or NULL
149 * if there was an error.
151 static const char *parse_attr(const char *src, int lineno, const char *cp,
152 struct attr_state *e)
154 const char *ep, *equals;
155 int len;
157 ep = cp + strcspn(cp, blank);
158 equals = strchr(cp, '=');
159 if (equals && ep < equals)
160 equals = NULL;
161 if (equals)
162 len = equals - cp;
163 else
164 len = ep - cp;
165 if (!e) {
166 if (*cp == '-' || *cp == '!') {
167 cp++;
168 len--;
170 if (invalid_attr_name(cp, len)) {
171 fprintf(stderr,
172 "%.*s is not a valid attribute name: %s:%d\n",
173 len, cp, src, lineno);
174 return NULL;
176 } else {
177 if (*cp == '-' || *cp == '!') {
178 e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
179 cp++;
180 len--;
182 else if (!equals)
183 e->setto = ATTR__TRUE;
184 else {
185 e->setto = xmemdupz(equals + 1, ep - equals - 1);
187 e->attr = git_attr_internal(cp, len);
189 return ep + strspn(ep, blank);
192 static struct match_attr *parse_attr_line(const char *line, const char *src,
193 int lineno, int macro_ok)
195 int namelen;
196 int num_attr, i;
197 const char *cp, *name, *states;
198 struct match_attr *res = NULL;
199 int is_macro;
201 cp = line + strspn(line, blank);
202 if (!*cp || *cp == '#')
203 return NULL;
204 name = cp;
205 namelen = strcspn(name, blank);
206 if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
207 !prefixcmp(name, ATTRIBUTE_MACRO_PREFIX)) {
208 if (!macro_ok) {
209 fprintf(stderr, "%s not allowed: %s:%d\n",
210 name, src, lineno);
211 return NULL;
213 is_macro = 1;
214 name += strlen(ATTRIBUTE_MACRO_PREFIX);
215 name += strspn(name, blank);
216 namelen = strcspn(name, blank);
217 if (invalid_attr_name(name, namelen)) {
218 fprintf(stderr,
219 "%.*s is not a valid attribute name: %s:%d\n",
220 namelen, name, src, lineno);
221 return NULL;
224 else
225 is_macro = 0;
227 states = name + namelen;
228 states += strspn(states, blank);
230 /* First pass to count the attr_states */
231 for (cp = states, num_attr = 0; *cp; num_attr++) {
232 cp = parse_attr(src, lineno, cp, NULL);
233 if (!cp)
234 return NULL;
237 res = xcalloc(1,
238 sizeof(*res) +
239 sizeof(struct attr_state) * num_attr +
240 (is_macro ? 0 : namelen + 1));
241 if (is_macro)
242 res->u.attr = git_attr_internal(name, namelen);
243 else {
244 res->u.pattern = (char *)&(res->state[num_attr]);
245 memcpy(res->u.pattern, name, namelen);
246 res->u.pattern[namelen] = 0;
248 res->is_macro = is_macro;
249 res->num_attr = num_attr;
251 /* Second pass to fill the attr_states */
252 for (cp = states, i = 0; *cp; i++) {
253 cp = parse_attr(src, lineno, cp, &(res->state[i]));
256 return res;
260 * Like info/exclude and .gitignore, the attribute information can
261 * come from many places.
263 * (1) .gitattribute file of the same directory;
264 * (2) .gitattribute file of the parent directory if (1) does not have
265 * any match; this goes recursively upwards, just like .gitignore.
266 * (3) $GIT_DIR/info/attributes, which overrides both of the above.
268 * In the same file, later entries override the earlier match, so in the
269 * global list, we would have entries from info/attributes the earliest
270 * (reading the file from top to bottom), .gitattribute of the root
271 * directory (again, reading the file from top to bottom) down to the
272 * current directory, and then scan the list backwards to find the first match.
273 * This is exactly the same as what excluded() does in dir.c to deal with
274 * .gitignore
277 static struct attr_stack {
278 struct attr_stack *prev;
279 char *origin;
280 unsigned num_matches;
281 unsigned alloc;
282 struct match_attr **attrs;
283 } *attr_stack;
285 static void free_attr_elem(struct attr_stack *e)
287 int i;
288 free(e->origin);
289 for (i = 0; i < e->num_matches; i++) {
290 struct match_attr *a = e->attrs[i];
291 int j;
292 for (j = 0; j < a->num_attr; j++) {
293 const char *setto = a->state[j].setto;
294 if (setto == ATTR__TRUE ||
295 setto == ATTR__FALSE ||
296 setto == ATTR__UNSET ||
297 setto == ATTR__UNKNOWN)
299 else
300 free((char *) setto);
302 free(a);
304 free(e->attrs);
305 free(e);
308 static const char *builtin_attr[] = {
309 "[attr]binary -diff -text",
310 NULL,
313 static void handle_attr_line(struct attr_stack *res,
314 const char *line,
315 const char *src,
316 int lineno,
317 int macro_ok)
319 struct match_attr *a;
321 a = parse_attr_line(line, src, lineno, macro_ok);
322 if (!a)
323 return;
324 if (res->alloc <= res->num_matches) {
325 res->alloc = alloc_nr(res->num_matches);
326 res->attrs = xrealloc(res->attrs,
327 sizeof(struct match_attr *) *
328 res->alloc);
330 res->attrs[res->num_matches++] = a;
333 static struct attr_stack *read_attr_from_array(const char **list)
335 struct attr_stack *res;
336 const char *line;
337 int lineno = 0;
339 res = xcalloc(1, sizeof(*res));
340 while ((line = *(list++)) != NULL)
341 handle_attr_line(res, line, "[builtin]", ++lineno, 1);
342 return res;
345 static enum git_attr_direction direction;
346 static struct index_state *use_index;
348 static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
350 FILE *fp = fopen(path, "r");
351 struct attr_stack *res;
352 char buf[2048];
353 int lineno = 0;
355 if (!fp)
356 return NULL;
357 res = xcalloc(1, sizeof(*res));
358 while (fgets(buf, sizeof(buf), fp))
359 handle_attr_line(res, buf, path, ++lineno, macro_ok);
360 fclose(fp);
361 return res;
364 static void *read_index_data(const char *path)
366 int pos, len;
367 unsigned long sz;
368 enum object_type type;
369 void *data;
370 struct index_state *istate = use_index ? use_index : &the_index;
372 len = strlen(path);
373 pos = index_name_pos(istate, path, len);
374 if (pos < 0) {
376 * We might be in the middle of a merge, in which
377 * case we would read stage #2 (ours).
379 int i;
380 for (i = -pos - 1;
381 (pos < 0 && i < istate->cache_nr &&
382 !strcmp(istate->cache[i]->name, path));
383 i++)
384 if (ce_stage(istate->cache[i]) == 2)
385 pos = i;
387 if (pos < 0)
388 return NULL;
389 data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
390 if (!data || type != OBJ_BLOB) {
391 free(data);
392 return NULL;
394 return data;
397 static struct attr_stack *read_attr_from_index(const char *path, int macro_ok)
399 struct attr_stack *res;
400 char *buf, *sp;
401 int lineno = 0;
403 buf = read_index_data(path);
404 if (!buf)
405 return NULL;
407 res = xcalloc(1, sizeof(*res));
408 for (sp = buf; *sp; ) {
409 char *ep;
410 int more;
411 for (ep = sp; *ep && *ep != '\n'; ep++)
413 more = (*ep == '\n');
414 *ep = '\0';
415 handle_attr_line(res, sp, path, ++lineno, macro_ok);
416 sp = ep + more;
418 free(buf);
419 return res;
422 static struct attr_stack *read_attr(const char *path, int macro_ok)
424 struct attr_stack *res;
426 if (direction == GIT_ATTR_CHECKOUT) {
427 res = read_attr_from_index(path, macro_ok);
428 if (!res)
429 res = read_attr_from_file(path, macro_ok);
431 else if (direction == GIT_ATTR_CHECKIN) {
432 res = read_attr_from_file(path, macro_ok);
433 if (!res)
435 * There is no checked out .gitattributes file there, but
436 * we might have it in the index. We allow operation in a
437 * sparsely checked out work tree, so read from it.
439 res = read_attr_from_index(path, macro_ok);
441 else
442 res = read_attr_from_index(path, macro_ok);
443 if (!res)
444 res = xcalloc(1, sizeof(*res));
445 return res;
448 #if DEBUG_ATTR
449 static void debug_info(const char *what, struct attr_stack *elem)
451 fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
453 static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
455 const char *value = v;
457 if (ATTR_TRUE(value))
458 value = "set";
459 else if (ATTR_FALSE(value))
460 value = "unset";
461 else if (ATTR_UNSET(value))
462 value = "unspecified";
464 fprintf(stderr, "%s: %s => %s (%s)\n",
465 what, attr->name, (char *) value, match);
467 #define debug_push(a) debug_info("push", (a))
468 #define debug_pop(a) debug_info("pop", (a))
469 #else
470 #define debug_push(a) do { ; } while (0)
471 #define debug_pop(a) do { ; } while (0)
472 #define debug_set(a,b,c,d) do { ; } while (0)
473 #endif
475 static void drop_attr_stack(void)
477 while (attr_stack) {
478 struct attr_stack *elem = attr_stack;
479 attr_stack = elem->prev;
480 free_attr_elem(elem);
484 static const char *git_etc_gitattributes(void)
486 static const char *system_wide;
487 if (!system_wide)
488 system_wide = system_path(ETC_GITATTRIBUTES);
489 return system_wide;
492 static int git_attr_system(void)
494 return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
497 static void bootstrap_attr_stack(void)
499 struct attr_stack *elem;
500 char *xdg_attributes_file;
502 if (attr_stack)
503 return;
505 elem = read_attr_from_array(builtin_attr);
506 elem->origin = NULL;
507 elem->prev = attr_stack;
508 attr_stack = elem;
510 if (git_attr_system()) {
511 elem = read_attr_from_file(git_etc_gitattributes(), 1);
512 if (elem) {
513 elem->origin = NULL;
514 elem->prev = attr_stack;
515 attr_stack = elem;
519 if (!git_attributes_file) {
520 home_config_paths(NULL, &xdg_attributes_file, "attributes");
521 git_attributes_file = xdg_attributes_file;
523 if (git_attributes_file) {
524 elem = read_attr_from_file(git_attributes_file, 1);
525 if (elem) {
526 elem->origin = NULL;
527 elem->prev = attr_stack;
528 attr_stack = elem;
532 if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
533 elem = read_attr(GITATTRIBUTES_FILE, 1);
534 elem->origin = xstrdup("");
535 elem->prev = attr_stack;
536 attr_stack = elem;
537 debug_push(elem);
540 elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
541 if (!elem)
542 elem = xcalloc(1, sizeof(*elem));
543 elem->origin = NULL;
544 elem->prev = attr_stack;
545 attr_stack = elem;
548 static void prepare_attr_stack(const char *path)
550 struct attr_stack *elem, *info;
551 int dirlen, len;
552 const char *cp;
554 cp = strrchr(path, '/');
555 if (!cp)
556 dirlen = 0;
557 else
558 dirlen = cp - path;
561 * At the bottom of the attribute stack is the built-in
562 * set of attribute definitions, followed by the contents
563 * of $(prefix)/etc/gitattributes and a file specified by
564 * core.attributesfile. Then, contents from
565 * .gitattribute files from directories closer to the
566 * root to the ones in deeper directories are pushed
567 * to the stack. Finally, at the very top of the stack
568 * we always keep the contents of $GIT_DIR/info/attributes.
570 * When checking, we use entries from near the top of the
571 * stack, preferring $GIT_DIR/info/attributes, then
572 * .gitattributes in deeper directories to shallower ones,
573 * and finally use the built-in set as the default.
575 bootstrap_attr_stack();
578 * Pop the "info" one that is always at the top of the stack.
580 info = attr_stack;
581 attr_stack = info->prev;
584 * Pop the ones from directories that are not the prefix of
585 * the path we are checking. Break out of the loop when we see
586 * the root one (whose origin is an empty string "") or the builtin
587 * one (whose origin is NULL) without popping it.
589 while (attr_stack->origin) {
590 int namelen = strlen(attr_stack->origin);
592 elem = attr_stack;
593 if (namelen <= dirlen &&
594 !strncmp(elem->origin, path, namelen) &&
595 (!namelen || path[namelen] == '/'))
596 break;
598 debug_pop(elem);
599 attr_stack = elem->prev;
600 free_attr_elem(elem);
604 * Read from parent directories and push them down
606 if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
608 * bootstrap_attr_stack() should have added, and the
609 * above loop should have stopped before popping, the
610 * root element whose attr_stack->origin is set to an
611 * empty string.
613 struct strbuf pathbuf = STRBUF_INIT;
615 assert(attr_stack->origin);
616 while (1) {
617 len = strlen(attr_stack->origin);
618 if (dirlen <= len)
619 break;
620 cp = memchr(path + len + 1, '/', dirlen - len - 1);
621 if (!cp)
622 cp = path + dirlen;
623 strbuf_add(&pathbuf, path, cp - path);
624 strbuf_addch(&pathbuf, '/');
625 strbuf_addstr(&pathbuf, GITATTRIBUTES_FILE);
626 elem = read_attr(pathbuf.buf, 0);
627 strbuf_setlen(&pathbuf, cp - path);
628 elem->origin = strbuf_detach(&pathbuf, NULL);
629 elem->prev = attr_stack;
630 attr_stack = elem;
631 debug_push(elem);
634 strbuf_release(&pathbuf);
638 * Finally push the "info" one at the top of the stack.
640 info->prev = attr_stack;
641 attr_stack = info;
644 static int path_matches(const char *pathname, int pathlen,
645 const char *pattern,
646 const char *base, int baselen)
648 if (!strchr(pattern, '/')) {
649 /* match basename */
650 const char *basename = strrchr(pathname, '/');
651 basename = basename ? basename + 1 : pathname;
652 return (fnmatch_icase(pattern, basename, 0) == 0);
655 * match with FNM_PATHNAME; the pattern has base implicitly
656 * in front of it.
658 if (*pattern == '/')
659 pattern++;
660 if (pathlen < baselen ||
661 (baselen && pathname[baselen] != '/') ||
662 strncmp(pathname, base, baselen))
663 return 0;
664 if (baselen != 0)
665 baselen++;
666 return fnmatch_icase(pattern, pathname + baselen, FNM_PATHNAME) == 0;
669 static int macroexpand_one(int attr_nr, int rem);
671 static int fill_one(const char *what, struct match_attr *a, int rem)
673 struct git_attr_check *check = check_all_attr;
674 int i;
676 for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) {
677 struct git_attr *attr = a->state[i].attr;
678 const char **n = &(check[attr->attr_nr].value);
679 const char *v = a->state[i].setto;
681 if (*n == ATTR__UNKNOWN) {
682 debug_set(what,
683 a->is_macro ? a->u.attr->name : a->u.pattern,
684 attr, v);
685 *n = v;
686 rem--;
687 rem = macroexpand_one(attr->attr_nr, rem);
690 return rem;
693 static int fill(const char *path, int pathlen, struct attr_stack *stk, int rem)
695 int i;
696 const char *base = stk->origin ? stk->origin : "";
698 for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
699 struct match_attr *a = stk->attrs[i];
700 if (a->is_macro)
701 continue;
702 if (path_matches(path, pathlen,
703 a->u.pattern, base, strlen(base)))
704 rem = fill_one("fill", a, rem);
706 return rem;
709 static int macroexpand_one(int attr_nr, int rem)
711 struct attr_stack *stk;
712 struct match_attr *a = NULL;
713 int i;
715 if (check_all_attr[attr_nr].value != ATTR__TRUE)
716 return rem;
718 for (stk = attr_stack; !a && stk; stk = stk->prev)
719 for (i = stk->num_matches - 1; !a && 0 <= i; i--) {
720 struct match_attr *ma = stk->attrs[i];
721 if (!ma->is_macro)
722 continue;
723 if (ma->u.attr->attr_nr == attr_nr)
724 a = ma;
727 if (a)
728 rem = fill_one("expand", a, rem);
730 return rem;
734 * Collect all attributes for path into the array pointed to by
735 * check_all_attr.
737 static void collect_all_attrs(const char *path)
739 struct attr_stack *stk;
740 int i, pathlen, rem;
742 prepare_attr_stack(path);
743 for (i = 0; i < attr_nr; i++)
744 check_all_attr[i].value = ATTR__UNKNOWN;
746 pathlen = strlen(path);
747 rem = attr_nr;
748 for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
749 rem = fill(path, pathlen, stk, rem);
752 int git_check_attr(const char *path, int num, struct git_attr_check *check)
754 int i;
756 collect_all_attrs(path);
758 for (i = 0; i < num; i++) {
759 const char *value = check_all_attr[check[i].attr->attr_nr].value;
760 if (value == ATTR__UNKNOWN)
761 value = ATTR__UNSET;
762 check[i].value = value;
765 return 0;
768 int git_all_attrs(const char *path, int *num, struct git_attr_check **check)
770 int i, count, j;
772 collect_all_attrs(path);
774 /* Count the number of attributes that are set. */
775 count = 0;
776 for (i = 0; i < attr_nr; i++) {
777 const char *value = check_all_attr[i].value;
778 if (value != ATTR__UNSET && value != ATTR__UNKNOWN)
779 ++count;
781 *num = count;
782 *check = xmalloc(sizeof(**check) * count);
783 j = 0;
784 for (i = 0; i < attr_nr; i++) {
785 const char *value = check_all_attr[i].value;
786 if (value != ATTR__UNSET && value != ATTR__UNKNOWN) {
787 (*check)[j].attr = check_all_attr[i].attr;
788 (*check)[j].value = value;
789 ++j;
793 return 0;
796 void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
798 enum git_attr_direction old = direction;
800 if (is_bare_repository() && new != GIT_ATTR_INDEX)
801 die("BUG: non-INDEX attr direction in a bare repo");
803 direction = new;
804 if (new != old)
805 drop_attr_stack();
806 use_index = istate;