log and friends: --second-parent
[git/mjg.git] / attr.c
blobe2f9377891a7f6e0d56803016726e3cd3137fdc2
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;
118 struct pattern {
119 const char *pattern;
120 int patternlen;
121 int nowildcardlen;
122 int flags; /* EXC_FLAG_* */
126 * One rule, as from a .gitattributes file.
128 * If is_macro is true, then u.attr is a pointer to the git_attr being
129 * defined.
131 * If is_macro is false, then u.pattern points at the filename pattern
132 * to which the rule applies. (The memory pointed to is part of the
133 * memory block allocated for the match_attr instance.)
135 * In either case, num_attr is the number of attributes affected by
136 * this rule, and state is an array listing them. The attributes are
137 * listed as they appear in the file (macros unexpanded).
139 struct match_attr {
140 union {
141 struct pattern pat;
142 struct git_attr *attr;
143 } u;
144 char is_macro;
145 unsigned num_attr;
146 struct attr_state state[FLEX_ARRAY];
149 static const char blank[] = " \t\r\n";
152 * Parse a whitespace-delimited attribute state (i.e., "attr",
153 * "-attr", "!attr", or "attr=value") from the string starting at src.
154 * If e is not NULL, write the results to *e. Return a pointer to the
155 * remainder of the string (with leading whitespace removed), or NULL
156 * if there was an error.
158 static const char *parse_attr(const char *src, int lineno, const char *cp,
159 struct attr_state *e)
161 const char *ep, *equals;
162 int len;
164 ep = cp + strcspn(cp, blank);
165 equals = strchr(cp, '=');
166 if (equals && ep < equals)
167 equals = NULL;
168 if (equals)
169 len = equals - cp;
170 else
171 len = ep - cp;
172 if (!e) {
173 if (*cp == '-' || *cp == '!') {
174 cp++;
175 len--;
177 if (invalid_attr_name(cp, len)) {
178 fprintf(stderr,
179 "%.*s is not a valid attribute name: %s:%d\n",
180 len, cp, src, lineno);
181 return NULL;
183 } else {
184 if (*cp == '-' || *cp == '!') {
185 e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
186 cp++;
187 len--;
189 else if (!equals)
190 e->setto = ATTR__TRUE;
191 else {
192 e->setto = xmemdupz(equals + 1, ep - equals - 1);
194 e->attr = git_attr_internal(cp, len);
196 return ep + strspn(ep, blank);
199 static struct match_attr *parse_attr_line(const char *line, const char *src,
200 int lineno, int macro_ok)
202 int namelen;
203 int num_attr, i;
204 const char *cp, *name, *states;
205 struct match_attr *res = NULL;
206 int is_macro;
208 cp = line + strspn(line, blank);
209 if (!*cp || *cp == '#')
210 return NULL;
211 name = cp;
212 namelen = strcspn(name, blank);
213 if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
214 !prefixcmp(name, ATTRIBUTE_MACRO_PREFIX)) {
215 if (!macro_ok) {
216 fprintf(stderr, "%s not allowed: %s:%d\n",
217 name, src, lineno);
218 return NULL;
220 is_macro = 1;
221 name += strlen(ATTRIBUTE_MACRO_PREFIX);
222 name += strspn(name, blank);
223 namelen = strcspn(name, blank);
224 if (invalid_attr_name(name, namelen)) {
225 fprintf(stderr,
226 "%.*s is not a valid attribute name: %s:%d\n",
227 namelen, name, src, lineno);
228 return NULL;
231 else
232 is_macro = 0;
234 states = name + namelen;
235 states += strspn(states, blank);
237 /* First pass to count the attr_states */
238 for (cp = states, num_attr = 0; *cp; num_attr++) {
239 cp = parse_attr(src, lineno, cp, NULL);
240 if (!cp)
241 return NULL;
244 res = xcalloc(1,
245 sizeof(*res) +
246 sizeof(struct attr_state) * num_attr +
247 (is_macro ? 0 : namelen + 1));
248 if (is_macro)
249 res->u.attr = git_attr_internal(name, namelen);
250 else {
251 char *p = (char *)&(res->state[num_attr]);
252 memcpy(p, name, namelen);
253 res->u.pat.pattern = p;
254 parse_exclude_pattern(&res->u.pat.pattern,
255 &res->u.pat.patternlen,
256 &res->u.pat.flags,
257 &res->u.pat.nowildcardlen);
258 if (res->u.pat.flags & EXC_FLAG_NEGATIVE) {
259 warning(_("Negative patterns are ignored in git attributes\n"
260 "Use '\\!' for literal leading exclamation."));
261 return NULL;
264 res->is_macro = is_macro;
265 res->num_attr = num_attr;
267 /* Second pass to fill the attr_states */
268 for (cp = states, i = 0; *cp; i++) {
269 cp = parse_attr(src, lineno, cp, &(res->state[i]));
272 return res;
276 * Like info/exclude and .gitignore, the attribute information can
277 * come from many places.
279 * (1) .gitattribute file of the same directory;
280 * (2) .gitattribute file of the parent directory if (1) does not have
281 * any match; this goes recursively upwards, just like .gitignore.
282 * (3) $GIT_DIR/info/attributes, which overrides both of the above.
284 * In the same file, later entries override the earlier match, so in the
285 * global list, we would have entries from info/attributes the earliest
286 * (reading the file from top to bottom), .gitattribute of the root
287 * directory (again, reading the file from top to bottom) down to the
288 * current directory, and then scan the list backwards to find the first match.
289 * This is exactly the same as what is_excluded() does in dir.c to deal with
290 * .gitignore
293 static struct attr_stack {
294 struct attr_stack *prev;
295 char *origin;
296 size_t originlen;
297 unsigned num_matches;
298 unsigned alloc;
299 struct match_attr **attrs;
300 } *attr_stack;
302 static void free_attr_elem(struct attr_stack *e)
304 int i;
305 free(e->origin);
306 for (i = 0; i < e->num_matches; i++) {
307 struct match_attr *a = e->attrs[i];
308 int j;
309 for (j = 0; j < a->num_attr; j++) {
310 const char *setto = a->state[j].setto;
311 if (setto == ATTR__TRUE ||
312 setto == ATTR__FALSE ||
313 setto == ATTR__UNSET ||
314 setto == ATTR__UNKNOWN)
316 else
317 free((char *) setto);
319 free(a);
321 free(e->attrs);
322 free(e);
325 static const char *builtin_attr[] = {
326 "[attr]binary -diff -merge -text",
327 NULL,
330 static void handle_attr_line(struct attr_stack *res,
331 const char *line,
332 const char *src,
333 int lineno,
334 int macro_ok)
336 struct match_attr *a;
338 a = parse_attr_line(line, src, lineno, macro_ok);
339 if (!a)
340 return;
341 if (res->alloc <= res->num_matches) {
342 res->alloc = alloc_nr(res->num_matches);
343 res->attrs = xrealloc(res->attrs,
344 sizeof(struct match_attr *) *
345 res->alloc);
347 res->attrs[res->num_matches++] = a;
350 static struct attr_stack *read_attr_from_array(const char **list)
352 struct attr_stack *res;
353 const char *line;
354 int lineno = 0;
356 res = xcalloc(1, sizeof(*res));
357 while ((line = *(list++)) != NULL)
358 handle_attr_line(res, line, "[builtin]", ++lineno, 1);
359 return res;
362 static enum git_attr_direction direction;
363 static struct index_state *use_index;
365 static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
367 FILE *fp = fopen(path, "r");
368 struct attr_stack *res;
369 char buf[2048];
370 int lineno = 0;
372 if (!fp) {
373 if (errno != ENOENT && errno != ENOTDIR)
374 warn_on_inaccessible(path);
375 return NULL;
377 res = xcalloc(1, sizeof(*res));
378 while (fgets(buf, sizeof(buf), fp))
379 handle_attr_line(res, buf, path, ++lineno, macro_ok);
380 fclose(fp);
381 return res;
384 static void *read_index_data(const char *path)
386 int pos, len;
387 unsigned long sz;
388 enum object_type type;
389 void *data;
390 struct index_state *istate = use_index ? use_index : &the_index;
392 len = strlen(path);
393 pos = index_name_pos(istate, path, len);
394 if (pos < 0) {
396 * We might be in the middle of a merge, in which
397 * case we would read stage #2 (ours).
399 int i;
400 for (i = -pos - 1;
401 (pos < 0 && i < istate->cache_nr &&
402 !strcmp(istate->cache[i]->name, path));
403 i++)
404 if (ce_stage(istate->cache[i]) == 2)
405 pos = i;
407 if (pos < 0)
408 return NULL;
409 data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
410 if (!data || type != OBJ_BLOB) {
411 free(data);
412 return NULL;
414 return data;
417 static struct attr_stack *read_attr_from_index(const char *path, int macro_ok)
419 struct attr_stack *res;
420 char *buf, *sp;
421 int lineno = 0;
423 buf = read_index_data(path);
424 if (!buf)
425 return NULL;
427 res = xcalloc(1, sizeof(*res));
428 for (sp = buf; *sp; ) {
429 char *ep;
430 int more;
431 for (ep = sp; *ep && *ep != '\n'; ep++)
433 more = (*ep == '\n');
434 *ep = '\0';
435 handle_attr_line(res, sp, path, ++lineno, macro_ok);
436 sp = ep + more;
438 free(buf);
439 return res;
442 static struct attr_stack *read_attr(const char *path, int macro_ok)
444 struct attr_stack *res;
446 if (direction == GIT_ATTR_CHECKOUT) {
447 res = read_attr_from_index(path, macro_ok);
448 if (!res)
449 res = read_attr_from_file(path, macro_ok);
451 else if (direction == GIT_ATTR_CHECKIN) {
452 res = read_attr_from_file(path, macro_ok);
453 if (!res)
455 * There is no checked out .gitattributes file there, but
456 * we might have it in the index. We allow operation in a
457 * sparsely checked out work tree, so read from it.
459 res = read_attr_from_index(path, macro_ok);
461 else
462 res = read_attr_from_index(path, macro_ok);
463 if (!res)
464 res = xcalloc(1, sizeof(*res));
465 return res;
468 #if DEBUG_ATTR
469 static void debug_info(const char *what, struct attr_stack *elem)
471 fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
473 static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
475 const char *value = v;
477 if (ATTR_TRUE(value))
478 value = "set";
479 else if (ATTR_FALSE(value))
480 value = "unset";
481 else if (ATTR_UNSET(value))
482 value = "unspecified";
484 fprintf(stderr, "%s: %s => %s (%s)\n",
485 what, attr->name, (char *) value, match);
487 #define debug_push(a) debug_info("push", (a))
488 #define debug_pop(a) debug_info("pop", (a))
489 #else
490 #define debug_push(a) do { ; } while (0)
491 #define debug_pop(a) do { ; } while (0)
492 #define debug_set(a,b,c,d) do { ; } while (0)
493 #endif
495 static void drop_attr_stack(void)
497 while (attr_stack) {
498 struct attr_stack *elem = attr_stack;
499 attr_stack = elem->prev;
500 free_attr_elem(elem);
504 static const char *git_etc_gitattributes(void)
506 static const char *system_wide;
507 if (!system_wide)
508 system_wide = system_path(ETC_GITATTRIBUTES);
509 return system_wide;
512 static int git_attr_system(void)
514 return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
517 static void bootstrap_attr_stack(void)
519 struct attr_stack *elem;
520 char *xdg_attributes_file;
522 if (attr_stack)
523 return;
525 elem = read_attr_from_array(builtin_attr);
526 elem->origin = NULL;
527 elem->prev = attr_stack;
528 attr_stack = elem;
530 if (git_attr_system()) {
531 elem = read_attr_from_file(git_etc_gitattributes(), 1);
532 if (elem) {
533 elem->origin = NULL;
534 elem->prev = attr_stack;
535 attr_stack = elem;
539 if (!git_attributes_file) {
540 home_config_paths(NULL, &xdg_attributes_file, "attributes");
541 git_attributes_file = xdg_attributes_file;
543 if (git_attributes_file) {
544 elem = read_attr_from_file(git_attributes_file, 1);
545 if (elem) {
546 elem->origin = NULL;
547 elem->prev = attr_stack;
548 attr_stack = elem;
552 if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
553 elem = read_attr(GITATTRIBUTES_FILE, 1);
554 elem->origin = xstrdup("");
555 elem->originlen = 0;
556 elem->prev = attr_stack;
557 attr_stack = elem;
558 debug_push(elem);
561 elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
562 if (!elem)
563 elem = xcalloc(1, sizeof(*elem));
564 elem->origin = NULL;
565 elem->prev = attr_stack;
566 attr_stack = elem;
569 static void prepare_attr_stack(const char *path, int dirlen)
571 struct attr_stack *elem, *info;
572 int len;
573 const char *cp;
576 * At the bottom of the attribute stack is the built-in
577 * set of attribute definitions, followed by the contents
578 * of $(prefix)/etc/gitattributes and a file specified by
579 * core.attributesfile. Then, contents from
580 * .gitattribute files from directories closer to the
581 * root to the ones in deeper directories are pushed
582 * to the stack. Finally, at the very top of the stack
583 * we always keep the contents of $GIT_DIR/info/attributes.
585 * When checking, we use entries from near the top of the
586 * stack, preferring $GIT_DIR/info/attributes, then
587 * .gitattributes in deeper directories to shallower ones,
588 * and finally use the built-in set as the default.
590 bootstrap_attr_stack();
593 * Pop the "info" one that is always at the top of the stack.
595 info = attr_stack;
596 attr_stack = info->prev;
599 * Pop the ones from directories that are not the prefix of
600 * the path we are checking. Break out of the loop when we see
601 * the root one (whose origin is an empty string "") or the builtin
602 * one (whose origin is NULL) without popping it.
604 while (attr_stack->origin) {
605 int namelen = strlen(attr_stack->origin);
607 elem = attr_stack;
608 if (namelen <= dirlen &&
609 !strncmp(elem->origin, path, namelen) &&
610 (!namelen || path[namelen] == '/'))
611 break;
613 debug_pop(elem);
614 attr_stack = elem->prev;
615 free_attr_elem(elem);
619 * Read from parent directories and push them down
621 if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
623 * bootstrap_attr_stack() should have added, and the
624 * above loop should have stopped before popping, the
625 * root element whose attr_stack->origin is set to an
626 * empty string.
628 struct strbuf pathbuf = STRBUF_INIT;
630 assert(attr_stack->origin);
631 while (1) {
632 len = strlen(attr_stack->origin);
633 if (dirlen <= len)
634 break;
635 cp = memchr(path + len + 1, '/', dirlen - len - 1);
636 if (!cp)
637 cp = path + dirlen;
638 strbuf_add(&pathbuf, path, cp - path);
639 strbuf_addch(&pathbuf, '/');
640 strbuf_addstr(&pathbuf, GITATTRIBUTES_FILE);
641 elem = read_attr(pathbuf.buf, 0);
642 strbuf_setlen(&pathbuf, cp - path);
643 elem->origin = strbuf_detach(&pathbuf, &elem->originlen);
644 elem->prev = attr_stack;
645 attr_stack = elem;
646 debug_push(elem);
649 strbuf_release(&pathbuf);
653 * Finally push the "info" one at the top of the stack.
655 info->prev = attr_stack;
656 attr_stack = info;
659 static int path_matches(const char *pathname, int pathlen,
660 const char *basename,
661 const struct pattern *pat,
662 const char *base, int baselen)
664 const char *pattern = pat->pattern;
665 int prefix = pat->nowildcardlen;
667 if ((pat->flags & EXC_FLAG_MUSTBEDIR) &&
668 ((!pathlen) || (pathname[pathlen-1] != '/')))
669 return 0;
671 if (pat->flags & EXC_FLAG_NODIR) {
672 return match_basename(basename,
673 pathlen - (basename - pathname),
674 pattern, prefix,
675 pat->patternlen, pat->flags);
677 return match_pathname(pathname, pathlen,
678 base, baselen,
679 pattern, prefix, pat->patternlen, pat->flags);
682 static int macroexpand_one(int attr_nr, int rem);
684 static int fill_one(const char *what, struct match_attr *a, int rem)
686 struct git_attr_check *check = check_all_attr;
687 int i;
689 for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) {
690 struct git_attr *attr = a->state[i].attr;
691 const char **n = &(check[attr->attr_nr].value);
692 const char *v = a->state[i].setto;
694 if (*n == ATTR__UNKNOWN) {
695 debug_set(what,
696 a->is_macro ? a->u.attr->name : a->u.pat.pattern,
697 attr, v);
698 *n = v;
699 rem--;
700 rem = macroexpand_one(attr->attr_nr, rem);
703 return rem;
706 static int fill(const char *path, int pathlen, const char *basename,
707 struct attr_stack *stk, int rem)
709 int i;
710 const char *base = stk->origin ? stk->origin : "";
712 for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
713 struct match_attr *a = stk->attrs[i];
714 if (a->is_macro)
715 continue;
716 if (path_matches(path, pathlen, basename,
717 &a->u.pat, base, stk->originlen))
718 rem = fill_one("fill", a, rem);
720 return rem;
723 static int macroexpand_one(int attr_nr, int rem)
725 struct attr_stack *stk;
726 struct match_attr *a = NULL;
727 int i;
729 if (check_all_attr[attr_nr].value != ATTR__TRUE)
730 return rem;
732 for (stk = attr_stack; !a && stk; stk = stk->prev)
733 for (i = stk->num_matches - 1; !a && 0 <= i; i--) {
734 struct match_attr *ma = stk->attrs[i];
735 if (!ma->is_macro)
736 continue;
737 if (ma->u.attr->attr_nr == attr_nr)
738 a = ma;
741 if (a)
742 rem = fill_one("expand", a, rem);
744 return rem;
748 * Collect all attributes for path into the array pointed to by
749 * check_all_attr.
751 static void collect_all_attrs(const char *path)
753 struct attr_stack *stk;
754 int i, pathlen, rem, dirlen;
755 const char *basename, *cp, *last_slash = NULL;
757 for (cp = path; *cp; cp++) {
758 if (*cp == '/' && cp[1])
759 last_slash = cp;
761 pathlen = cp - path;
762 if (last_slash) {
763 basename = last_slash + 1;
764 dirlen = last_slash - path;
765 } else {
766 basename = path;
767 dirlen = 0;
770 prepare_attr_stack(path, dirlen);
771 for (i = 0; i < attr_nr; i++)
772 check_all_attr[i].value = ATTR__UNKNOWN;
774 rem = attr_nr;
775 for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
776 rem = fill(path, pathlen, basename, stk, rem);
779 int git_check_attr(const char *path, int num, struct git_attr_check *check)
781 int i;
783 collect_all_attrs(path);
785 for (i = 0; i < num; i++) {
786 const char *value = check_all_attr[check[i].attr->attr_nr].value;
787 if (value == ATTR__UNKNOWN)
788 value = ATTR__UNSET;
789 check[i].value = value;
792 return 0;
795 int git_all_attrs(const char *path, int *num, struct git_attr_check **check)
797 int i, count, j;
799 collect_all_attrs(path);
801 /* Count the number of attributes that are set. */
802 count = 0;
803 for (i = 0; i < attr_nr; i++) {
804 const char *value = check_all_attr[i].value;
805 if (value != ATTR__UNSET && value != ATTR__UNKNOWN)
806 ++count;
808 *num = count;
809 *check = xmalloc(sizeof(**check) * count);
810 j = 0;
811 for (i = 0; i < attr_nr; i++) {
812 const char *value = check_all_attr[i].value;
813 if (value != ATTR__UNSET && value != ATTR__UNKNOWN) {
814 (*check)[j].attr = check_all_attr[i].attr;
815 (*check)[j].value = value;
816 ++j;
820 return 0;
823 void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
825 enum git_attr_direction old = direction;
827 if (is_bare_repository() && new != GIT_ATTR_INDEX)
828 die("BUG: non-INDEX attr direction in a bare repo");
830 direction = new;
831 if (new != old)
832 drop_attr_stack();
833 use_index = istate;