attr.con commit Merge branch 'aw/contrib-subtree-doc-asciidoctor' into maint (35049a2)
   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.
   5 *
   6 * One basic design decision here is that we are not going to support
   7 * an insanely large number of attributes.
   8 */
   9
  10#define NO_THE_INDEX_COMPATIBILITY_MACROS
  11#include "cache.h"
  12#include "exec_cmd.h"
  13#include "attr.h"
  14#include "dir.h"
  15#include "utf8.h"
  16#include "quote.h"
  17#include "thread-utils.h"
  18
  19const char git_attr__true[] = "(builtin)true";
  20const char git_attr__false[] = "\0(builtin)false";
  21static const char git_attr__unknown[] = "(builtin)unknown";
  22#define ATTR__TRUE git_attr__true
  23#define ATTR__FALSE git_attr__false
  24#define ATTR__UNSET NULL
  25#define ATTR__UNKNOWN git_attr__unknown
  26
  27#ifndef DEBUG_ATTR
  28#define DEBUG_ATTR 0
  29#endif
  30
  31struct git_attr {
  32        int attr_nr; /* unique attribute number */
  33        char name[FLEX_ARRAY]; /* attribute name */
  34};
  35
  36const char *git_attr_name(const struct git_attr *attr)
  37{
  38        return attr->name;
  39}
  40
  41struct attr_hashmap {
  42        struct hashmap map;
  43#ifndef NO_PTHREADS
  44        pthread_mutex_t mutex;
  45#endif
  46};
  47
  48static inline void hashmap_lock(struct attr_hashmap *map)
  49{
  50#ifndef NO_PTHREADS
  51        pthread_mutex_lock(&map->mutex);
  52#endif
  53}
  54
  55static inline void hashmap_unlock(struct attr_hashmap *map)
  56{
  57#ifndef NO_PTHREADS
  58        pthread_mutex_unlock(&map->mutex);
  59#endif
  60}
  61
  62/*
  63 * The global dictionary of all interned attributes.  This
  64 * is a singleton object which is shared between threads.
  65 * Access to this dictionary must be surrounded with a mutex.
  66 */
  67static struct attr_hashmap g_attr_hashmap;
  68
  69/* The container for objects stored in "struct attr_hashmap" */
  70struct attr_hash_entry {
  71        struct hashmap_entry ent; /* must be the first member! */
  72        const char *key; /* the key; memory should be owned by value */
  73        size_t keylen; /* length of the key */
  74        void *value; /* the stored value */
  75};
  76
  77/* attr_hashmap comparison function */
  78static int attr_hash_entry_cmp(const struct attr_hash_entry *a,
  79                               const struct attr_hash_entry *b,
  80                               void *unused)
  81{
  82        return (a->keylen != b->keylen) || strncmp(a->key, b->key, a->keylen);
  83}
  84
  85/* Initialize an 'attr_hashmap' object */
  86static void attr_hashmap_init(struct attr_hashmap *map)
  87{
  88        hashmap_init(&map->map, (hashmap_cmp_fn) attr_hash_entry_cmp, 0);
  89}
  90
  91/*
  92 * Retrieve the 'value' stored in a hashmap given the provided 'key'.
  93 * If there is no matching entry, return NULL.
  94 */
  95static void *attr_hashmap_get(struct attr_hashmap *map,
  96                              const char *key, size_t keylen)
  97{
  98        struct attr_hash_entry k;
  99        struct attr_hash_entry *e;
 100
 101        if (!map->map.tablesize)
 102                attr_hashmap_init(map);
 103
 104        hashmap_entry_init(&k, memhash(key, keylen));
 105        k.key = key;
 106        k.keylen = keylen;
 107        e = hashmap_get(&map->map, &k, NULL);
 108
 109        return e ? e->value : NULL;
 110}
 111
 112/* Add 'value' to a hashmap based on the provided 'key'. */
 113static void attr_hashmap_add(struct attr_hashmap *map,
 114                             const char *key, size_t keylen,
 115                             void *value)
 116{
 117        struct attr_hash_entry *e;
 118
 119        if (!map->map.tablesize)
 120                attr_hashmap_init(map);
 121
 122        e = xmalloc(sizeof(struct attr_hash_entry));
 123        hashmap_entry_init(e, memhash(key, keylen));
 124        e->key = key;
 125        e->keylen = keylen;
 126        e->value = value;
 127
 128        hashmap_add(&map->map, e);
 129}
 130
 131struct all_attrs_item {
 132        const struct git_attr *attr;
 133        const char *value;
 134        /*
 135         * If 'macro' is non-NULL, indicates that 'attr' is a macro based on
 136         * the current attribute stack and contains a pointer to the match_attr
 137         * definition of the macro
 138         */
 139        const struct match_attr *macro;
 140};
 141
 142/*
 143 * Reallocate and reinitialize the array of all attributes (which is used in
 144 * the attribute collection process) in 'check' based on the global dictionary
 145 * of attributes.
 146 */
 147static void all_attrs_init(struct attr_hashmap *map, struct attr_check *check)
 148{
 149        int i;
 150
 151        hashmap_lock(map);
 152
 153        if (map->map.size < check->all_attrs_nr)
 154                die("BUG: interned attributes shouldn't be deleted");
 155
 156        /*
 157         * If the number of attributes in the global dictionary has increased
 158         * (or this attr_check instance doesn't have an initialized all_attrs
 159         * field), reallocate the provided attr_check instance's all_attrs
 160         * field and fill each entry with its corresponding git_attr.
 161         */
 162        if (map->map.size != check->all_attrs_nr) {
 163                struct attr_hash_entry *e;
 164                struct hashmap_iter iter;
 165                hashmap_iter_init(&map->map, &iter);
 166
 167                REALLOC_ARRAY(check->all_attrs, map->map.size);
 168                check->all_attrs_nr = map->map.size;
 169
 170                while ((e = hashmap_iter_next(&iter))) {
 171                        const struct git_attr *a = e->value;
 172                        check->all_attrs[a->attr_nr].attr = a;
 173                }
 174        }
 175
 176        hashmap_unlock(map);
 177
 178        /*
 179         * Re-initialize every entry in check->all_attrs.
 180         * This re-initialization can live outside of the locked region since
 181         * the attribute dictionary is no longer being accessed.
 182         */
 183        for (i = 0; i < check->all_attrs_nr; i++) {
 184                check->all_attrs[i].value = ATTR__UNKNOWN;
 185                check->all_attrs[i].macro = NULL;
 186        }
 187}
 188
 189static int attr_name_valid(const char *name, size_t namelen)
 190{
 191        /*
 192         * Attribute name cannot begin with '-' and must consist of
 193         * characters from [-A-Za-z0-9_.].
 194         */
 195        if (namelen <= 0 || *name == '-')
 196                return 0;
 197        while (namelen--) {
 198                char ch = *name++;
 199                if (! (ch == '-' || ch == '.' || ch == '_' ||
 200                       ('0' <= ch && ch <= '9') ||
 201                       ('a' <= ch && ch <= 'z') ||
 202                       ('A' <= ch && ch <= 'Z')) )
 203                        return 0;
 204        }
 205        return 1;
 206}
 207
 208static void report_invalid_attr(const char *name, size_t len,
 209                                const char *src, int lineno)
 210{
 211        struct strbuf err = STRBUF_INIT;
 212        strbuf_addf(&err, _("%.*s is not a valid attribute name"),
 213                    (int) len, name);
 214        fprintf(stderr, "%s: %s:%d\n", err.buf, src, lineno);
 215        strbuf_release(&err);
 216}
 217
 218/*
 219 * Given a 'name', lookup and return the corresponding attribute in the global
 220 * dictionary.  If no entry is found, create a new attribute and store it in
 221 * the dictionary.
 222 */
 223static const struct git_attr *git_attr_internal(const char *name, int namelen)
 224{
 225        struct git_attr *a;
 226
 227        if (!attr_name_valid(name, namelen))
 228                return NULL;
 229
 230        hashmap_lock(&g_attr_hashmap);
 231
 232        a = attr_hashmap_get(&g_attr_hashmap, name, namelen);
 233
 234        if (!a) {
 235                FLEX_ALLOC_MEM(a, name, name, namelen);
 236                a->attr_nr = g_attr_hashmap.map.size;
 237
 238                attr_hashmap_add(&g_attr_hashmap, a->name, namelen, a);
 239                assert(a->attr_nr == (g_attr_hashmap.map.size - 1));
 240        }
 241
 242        hashmap_unlock(&g_attr_hashmap);
 243
 244        return a;
 245}
 246
 247const struct git_attr *git_attr(const char *name)
 248{
 249        return git_attr_internal(name, strlen(name));
 250}
 251
 252/* What does a matched pattern decide? */
 253struct attr_state {
 254        const struct git_attr *attr;
 255        const char *setto;
 256};
 257
 258struct pattern {
 259        const char *pattern;
 260        int patternlen;
 261        int nowildcardlen;
 262        unsigned flags;         /* EXC_FLAG_* */
 263};
 264
 265/*
 266 * One rule, as from a .gitattributes file.
 267 *
 268 * If is_macro is true, then u.attr is a pointer to the git_attr being
 269 * defined.
 270 *
 271 * If is_macro is false, then u.pat is the filename pattern to which the
 272 * rule applies.
 273 *
 274 * In either case, num_attr is the number of attributes affected by
 275 * this rule, and state is an array listing them.  The attributes are
 276 * listed as they appear in the file (macros unexpanded).
 277 */
 278struct match_attr {
 279        union {
 280                struct pattern pat;
 281                const struct git_attr *attr;
 282        } u;
 283        char is_macro;
 284        unsigned num_attr;
 285        struct attr_state state[FLEX_ARRAY];
 286};
 287
 288static const char blank[] = " \t\r\n";
 289
 290/*
 291 * Parse a whitespace-delimited attribute state (i.e., "attr",
 292 * "-attr", "!attr", or "attr=value") from the string starting at src.
 293 * If e is not NULL, write the results to *e.  Return a pointer to the
 294 * remainder of the string (with leading whitespace removed), or NULL
 295 * if there was an error.
 296 */
 297static const char *parse_attr(const char *src, int lineno, const char *cp,
 298                              struct attr_state *e)
 299{
 300        const char *ep, *equals;
 301        int len;
 302
 303        ep = cp + strcspn(cp, blank);
 304        equals = strchr(cp, '=');
 305        if (equals && ep < equals)
 306                equals = NULL;
 307        if (equals)
 308                len = equals - cp;
 309        else
 310                len = ep - cp;
 311        if (!e) {
 312                if (*cp == '-' || *cp == '!') {
 313                        cp++;
 314                        len--;
 315                }
 316                if (!attr_name_valid(cp, len)) {
 317                        report_invalid_attr(cp, len, src, lineno);
 318                        return NULL;
 319                }
 320        } else {
 321                /*
 322                 * As this function is always called twice, once with
 323                 * e == NULL in the first pass and then e != NULL in
 324                 * the second pass, no need for attr_name_valid()
 325                 * check here.
 326                 */
 327                if (*cp == '-' || *cp == '!') {
 328                        e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
 329                        cp++;
 330                        len--;
 331                }
 332                else if (!equals)
 333                        e->setto = ATTR__TRUE;
 334                else {
 335                        e->setto = xmemdupz(equals + 1, ep - equals - 1);
 336                }
 337                e->attr = git_attr_internal(cp, len);
 338        }
 339        return ep + strspn(ep, blank);
 340}
 341
 342static struct match_attr *parse_attr_line(const char *line, const char *src,
 343                                          int lineno, int macro_ok)
 344{
 345        int namelen;
 346        int num_attr, i;
 347        const char *cp, *name, *states;
 348        struct match_attr *res = NULL;
 349        int is_macro;
 350        struct strbuf pattern = STRBUF_INIT;
 351
 352        cp = line + strspn(line, blank);
 353        if (!*cp || *cp == '#')
 354                return NULL;
 355        name = cp;
 356
 357        if (*cp == '"' && !unquote_c_style(&pattern, name, &states)) {
 358                name = pattern.buf;
 359                namelen = pattern.len;
 360        } else {
 361                namelen = strcspn(name, blank);
 362                states = name + namelen;
 363        }
 364
 365        if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
 366            starts_with(name, ATTRIBUTE_MACRO_PREFIX)) {
 367                if (!macro_ok) {
 368                        fprintf(stderr, "%s not allowed: %s:%d\n",
 369                                name, src, lineno);
 370                        goto fail_return;
 371                }
 372                is_macro = 1;
 373                name += strlen(ATTRIBUTE_MACRO_PREFIX);
 374                name += strspn(name, blank);
 375                namelen = strcspn(name, blank);
 376                if (!attr_name_valid(name, namelen)) {
 377                        report_invalid_attr(name, namelen, src, lineno);
 378                        goto fail_return;
 379                }
 380        }
 381        else
 382                is_macro = 0;
 383
 384        states += strspn(states, blank);
 385
 386        /* First pass to count the attr_states */
 387        for (cp = states, num_attr = 0; *cp; num_attr++) {
 388                cp = parse_attr(src, lineno, cp, NULL);
 389                if (!cp)
 390                        goto fail_return;
 391        }
 392
 393        res = xcalloc(1,
 394                      sizeof(*res) +
 395                      sizeof(struct attr_state) * num_attr +
 396                      (is_macro ? 0 : namelen + 1));
 397        if (is_macro) {
 398                res->u.attr = git_attr_internal(name, namelen);
 399        } else {
 400                char *p = (char *)&(res->state[num_attr]);
 401                memcpy(p, name, namelen);
 402                res->u.pat.pattern = p;
 403                parse_exclude_pattern(&res->u.pat.pattern,
 404                                      &res->u.pat.patternlen,
 405                                      &res->u.pat.flags,
 406                                      &res->u.pat.nowildcardlen);
 407                if (res->u.pat.flags & EXC_FLAG_NEGATIVE) {
 408                        warning(_("Negative patterns are ignored in git attributes\n"
 409                                  "Use '\\!' for literal leading exclamation."));
 410                        goto fail_return;
 411                }
 412        }
 413        res->is_macro = is_macro;
 414        res->num_attr = num_attr;
 415
 416        /* Second pass to fill the attr_states */
 417        for (cp = states, i = 0; *cp; i++) {
 418                cp = parse_attr(src, lineno, cp, &(res->state[i]));
 419        }
 420
 421        strbuf_release(&pattern);
 422        return res;
 423
 424fail_return:
 425        strbuf_release(&pattern);
 426        free(res);
 427        return NULL;
 428}
 429
 430/*
 431 * Like info/exclude and .gitignore, the attribute information can
 432 * come from many places.
 433 *
 434 * (1) .gitattribute file of the same directory;
 435 * (2) .gitattribute file of the parent directory if (1) does not have
 436 *      any match; this goes recursively upwards, just like .gitignore.
 437 * (3) $GIT_DIR/info/attributes, which overrides both of the above.
 438 *
 439 * In the same file, later entries override the earlier match, so in the
 440 * global list, we would have entries from info/attributes the earliest
 441 * (reading the file from top to bottom), .gitattribute of the root
 442 * directory (again, reading the file from top to bottom) down to the
 443 * current directory, and then scan the list backwards to find the first match.
 444 * This is exactly the same as what is_excluded() does in dir.c to deal with
 445 * .gitignore file and info/excludes file as a fallback.
 446 */
 447
 448struct attr_stack {
 449        struct attr_stack *prev;
 450        char *origin;
 451        size_t originlen;
 452        unsigned num_matches;
 453        unsigned alloc;
 454        struct match_attr **attrs;
 455};
 456
 457static void attr_stack_free(struct attr_stack *e)
 458{
 459        int i;
 460        free(e->origin);
 461        for (i = 0; i < e->num_matches; i++) {
 462                struct match_attr *a = e->attrs[i];
 463                int j;
 464                for (j = 0; j < a->num_attr; j++) {
 465                        const char *setto = a->state[j].setto;
 466                        if (setto == ATTR__TRUE ||
 467                            setto == ATTR__FALSE ||
 468                            setto == ATTR__UNSET ||
 469                            setto == ATTR__UNKNOWN)
 470                                ;
 471                        else
 472                                free((char *) setto);
 473                }
 474                free(a);
 475        }
 476        free(e->attrs);
 477        free(e);
 478}
 479
 480static void drop_attr_stack(struct attr_stack **stack)
 481{
 482        while (*stack) {
 483                struct attr_stack *elem = *stack;
 484                *stack = elem->prev;
 485                attr_stack_free(elem);
 486        }
 487}
 488
 489/* List of all attr_check structs; access should be surrounded by mutex */
 490static struct check_vector {
 491        size_t nr;
 492        size_t alloc;
 493        struct attr_check **checks;
 494#ifndef NO_PTHREADS
 495        pthread_mutex_t mutex;
 496#endif
 497} check_vector;
 498
 499static inline void vector_lock(void)
 500{
 501#ifndef NO_PTHREADS
 502        pthread_mutex_lock(&check_vector.mutex);
 503#endif
 504}
 505
 506static inline void vector_unlock(void)
 507{
 508#ifndef NO_PTHREADS
 509        pthread_mutex_unlock(&check_vector.mutex);
 510#endif
 511}
 512
 513static void check_vector_add(struct attr_check *c)
 514{
 515        vector_lock();
 516
 517        ALLOC_GROW(check_vector.checks,
 518                   check_vector.nr + 1,
 519                   check_vector.alloc);
 520        check_vector.checks[check_vector.nr++] = c;
 521
 522        vector_unlock();
 523}
 524
 525static void check_vector_remove(struct attr_check *check)
 526{
 527        int i;
 528
 529        vector_lock();
 530
 531        /* Find entry */
 532        for (i = 0; i < check_vector.nr; i++)
 533                if (check_vector.checks[i] == check)
 534                        break;
 535
 536        if (i >= check_vector.nr)
 537                die("BUG: no entry found");
 538
 539        /* shift entries over */
 540        for (; i < check_vector.nr - 1; i++)
 541                check_vector.checks[i] = check_vector.checks[i + 1];
 542
 543        check_vector.nr--;
 544
 545        vector_unlock();
 546}
 547
 548/* Iterate through all attr_check instances and drop their stacks */
 549static void drop_all_attr_stacks(void)
 550{
 551        int i;
 552
 553        vector_lock();
 554
 555        for (i = 0; i < check_vector.nr; i++) {
 556                drop_attr_stack(&check_vector.checks[i]->stack);
 557        }
 558
 559        vector_unlock();
 560}
 561
 562struct attr_check *attr_check_alloc(void)
 563{
 564        struct attr_check *c = xcalloc(1, sizeof(struct attr_check));
 565
 566        /* save pointer to the check struct */
 567        check_vector_add(c);
 568
 569        return c;
 570}
 571
 572struct attr_check *attr_check_initl(const char *one, ...)
 573{
 574        struct attr_check *check;
 575        int cnt;
 576        va_list params;
 577        const char *param;
 578
 579        va_start(params, one);
 580        for (cnt = 1; (param = va_arg(params, const char *)) != NULL; cnt++)
 581                ;
 582        va_end(params);
 583
 584        check = attr_check_alloc();
 585        check->nr = cnt;
 586        check->alloc = cnt;
 587        check->items = xcalloc(cnt, sizeof(struct attr_check_item));
 588
 589        check->items[0].attr = git_attr(one);
 590        va_start(params, one);
 591        for (cnt = 1; cnt < check->nr; cnt++) {
 592                const struct git_attr *attr;
 593                param = va_arg(params, const char *);
 594                if (!param)
 595                        die("BUG: counted %d != ended at %d",
 596                            check->nr, cnt);
 597                attr = git_attr(param);
 598                if (!attr)
 599                        die("BUG: %s: not a valid attribute name", param);
 600                check->items[cnt].attr = attr;
 601        }
 602        va_end(params);
 603        return check;
 604}
 605
 606struct attr_check *attr_check_dup(const struct attr_check *check)
 607{
 608        struct attr_check *ret;
 609
 610        if (!check)
 611                return NULL;
 612
 613        ret = attr_check_alloc();
 614
 615        ret->nr = check->nr;
 616        ret->alloc = check->alloc;
 617        ALLOC_ARRAY(ret->items, ret->nr);
 618        COPY_ARRAY(ret->items, check->items, ret->nr);
 619
 620        return ret;
 621}
 622
 623struct attr_check_item *attr_check_append(struct attr_check *check,
 624                                          const struct git_attr *attr)
 625{
 626        struct attr_check_item *item;
 627
 628        ALLOC_GROW(check->items, check->nr + 1, check->alloc);
 629        item = &check->items[check->nr++];
 630        item->attr = attr;
 631        return item;
 632}
 633
 634void attr_check_reset(struct attr_check *check)
 635{
 636        check->nr = 0;
 637}
 638
 639void attr_check_clear(struct attr_check *check)
 640{
 641        free(check->items);
 642        check->items = NULL;
 643        check->alloc = 0;
 644        check->nr = 0;
 645
 646        free(check->all_attrs);
 647        check->all_attrs = NULL;
 648        check->all_attrs_nr = 0;
 649
 650        drop_attr_stack(&check->stack);
 651}
 652
 653void attr_check_free(struct attr_check *check)
 654{
 655        if (check) {
 656                /* Remove check from the check vector */
 657                check_vector_remove(check);
 658
 659                attr_check_clear(check);
 660                free(check);
 661        }
 662}
 663
 664static const char *builtin_attr[] = {
 665        "[attr]binary -diff -merge -text",
 666        NULL,
 667};
 668
 669static void handle_attr_line(struct attr_stack *res,
 670                             const char *line,
 671                             const char *src,
 672                             int lineno,
 673                             int macro_ok)
 674{
 675        struct match_attr *a;
 676
 677        a = parse_attr_line(line, src, lineno, macro_ok);
 678        if (!a)
 679                return;
 680        ALLOC_GROW(res->attrs, res->num_matches + 1, res->alloc);
 681        res->attrs[res->num_matches++] = a;
 682}
 683
 684static struct attr_stack *read_attr_from_array(const char **list)
 685{
 686        struct attr_stack *res;
 687        const char *line;
 688        int lineno = 0;
 689
 690        res = xcalloc(1, sizeof(*res));
 691        while ((line = *(list++)) != NULL)
 692                handle_attr_line(res, line, "[builtin]", ++lineno, 1);
 693        return res;
 694}
 695
 696/*
 697 * Callers into the attribute system assume there is a single, system-wide
 698 * global state where attributes are read from and when the state is flipped by
 699 * calling git_attr_set_direction(), the stack frames that have been
 700 * constructed need to be discarded so so that subsequent calls into the
 701 * attribute system will lazily read from the right place.  Since changing
 702 * direction causes a global paradigm shift, it should not ever be called while
 703 * another thread could potentially be calling into the attribute system.
 704 */
 705static enum git_attr_direction direction;
 706static struct index_state *use_index;
 707
 708void git_attr_set_direction(enum git_attr_direction new_direction,
 709                            struct index_state *istate)
 710{
 711        if (is_bare_repository() && new_direction != GIT_ATTR_INDEX)
 712                die("BUG: non-INDEX attr direction in a bare repo");
 713
 714        if (new_direction != direction)
 715                drop_all_attr_stacks();
 716
 717        direction = new_direction;
 718        use_index = istate;
 719}
 720
 721static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
 722{
 723        FILE *fp = fopen(path, "r");
 724        struct attr_stack *res;
 725        char buf[2048];
 726        int lineno = 0;
 727
 728        if (!fp) {
 729                if (errno != ENOENT && errno != ENOTDIR)
 730                        warn_on_inaccessible(path);
 731                return NULL;
 732        }
 733        res = xcalloc(1, sizeof(*res));
 734        while (fgets(buf, sizeof(buf), fp)) {
 735                char *bufp = buf;
 736                if (!lineno)
 737                        skip_utf8_bom(&bufp, strlen(bufp));
 738                handle_attr_line(res, bufp, path, ++lineno, macro_ok);
 739        }
 740        fclose(fp);
 741        return res;
 742}
 743
 744static struct attr_stack *read_attr_from_index(const char *path, int macro_ok)
 745{
 746        struct attr_stack *res;
 747        char *buf, *sp;
 748        int lineno = 0;
 749
 750        buf = read_blob_data_from_index(use_index ? use_index : &the_index, path, NULL);
 751        if (!buf)
 752                return NULL;
 753
 754        res = xcalloc(1, sizeof(*res));
 755        for (sp = buf; *sp; ) {
 756                char *ep;
 757                int more;
 758
 759                ep = strchrnul(sp, '\n');
 760                more = (*ep == '\n');
 761                *ep = '\0';
 762                handle_attr_line(res, sp, path, ++lineno, macro_ok);
 763                sp = ep + more;
 764        }
 765        free(buf);
 766        return res;
 767}
 768
 769static struct attr_stack *read_attr(const char *path, int macro_ok)
 770{
 771        struct attr_stack *res = NULL;
 772
 773        if (direction == GIT_ATTR_INDEX) {
 774                res = read_attr_from_index(path, macro_ok);
 775        } else if (!is_bare_repository()) {
 776                if (direction == GIT_ATTR_CHECKOUT) {
 777                        res = read_attr_from_index(path, macro_ok);
 778                        if (!res)
 779                                res = read_attr_from_file(path, macro_ok);
 780                } else if (direction == GIT_ATTR_CHECKIN) {
 781                        res = read_attr_from_file(path, macro_ok);
 782                        if (!res)
 783                                /*
 784                                 * There is no checked out .gitattributes file
 785                                 * there, but we might have it in the index.
 786                                 * We allow operation in a sparsely checked out
 787                                 * work tree, so read from it.
 788                                 */
 789                                res = read_attr_from_index(path, macro_ok);
 790                }
 791        }
 792
 793        if (!res)
 794                res = xcalloc(1, sizeof(*res));
 795        return res;
 796}
 797
 798#if DEBUG_ATTR
 799static void debug_info(const char *what, struct attr_stack *elem)
 800{
 801        fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
 802}
 803static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
 804{
 805        const char *value = v;
 806
 807        if (ATTR_TRUE(value))
 808                value = "set";
 809        else if (ATTR_FALSE(value))
 810                value = "unset";
 811        else if (ATTR_UNSET(value))
 812                value = "unspecified";
 813
 814        fprintf(stderr, "%s: %s => %s (%s)\n",
 815                what, attr->name, (char *) value, match);
 816}
 817#define debug_push(a) debug_info("push", (a))
 818#define debug_pop(a) debug_info("pop", (a))
 819#else
 820#define debug_push(a) do { ; } while (0)
 821#define debug_pop(a) do { ; } while (0)
 822#define debug_set(a,b,c,d) do { ; } while (0)
 823#endif /* DEBUG_ATTR */
 824
 825static const char *git_etc_gitattributes(void)
 826{
 827        static const char *system_wide;
 828        if (!system_wide)
 829                system_wide = system_path(ETC_GITATTRIBUTES);
 830        return system_wide;
 831}
 832
 833static const char *get_home_gitattributes(void)
 834{
 835        if (!git_attributes_file)
 836                git_attributes_file = xdg_config_home("attributes");
 837
 838        return git_attributes_file;
 839}
 840
 841static int git_attr_system(void)
 842{
 843        return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
 844}
 845
 846static GIT_PATH_FUNC(git_path_info_attributes, INFOATTRIBUTES_FILE)
 847
 848static void push_stack(struct attr_stack **attr_stack_p,
 849                       struct attr_stack *elem, char *origin, size_t originlen)
 850{
 851        if (elem) {
 852                elem->origin = origin;
 853                if (origin)
 854                        elem->originlen = originlen;
 855                elem->prev = *attr_stack_p;
 856                *attr_stack_p = elem;
 857        }
 858}
 859
 860static void bootstrap_attr_stack(struct attr_stack **stack)
 861{
 862        struct attr_stack *e;
 863
 864        if (*stack)
 865                return;
 866
 867        /* builtin frame */
 868        e = read_attr_from_array(builtin_attr);
 869        push_stack(stack, e, NULL, 0);
 870
 871        /* system-wide frame */
 872        if (git_attr_system()) {
 873                e = read_attr_from_file(git_etc_gitattributes(), 1);
 874                push_stack(stack, e, NULL, 0);
 875        }
 876
 877        /* home directory */
 878        if (get_home_gitattributes()) {
 879                e = read_attr_from_file(get_home_gitattributes(), 1);
 880                push_stack(stack, e, NULL, 0);
 881        }
 882
 883        /* root directory */
 884        e = read_attr(GITATTRIBUTES_FILE, 1);
 885        push_stack(stack, e, xstrdup(""), 0);
 886
 887        /* info frame */
 888        if (startup_info->have_repository)
 889                e = read_attr_from_file(git_path_info_attributes(), 1);
 890        else
 891                e = NULL;
 892        if (!e)
 893                e = xcalloc(1, sizeof(struct attr_stack));
 894        push_stack(stack, e, NULL, 0);
 895}
 896
 897static void prepare_attr_stack(const char *path, int dirlen,
 898                               struct attr_stack **stack)
 899{
 900        struct attr_stack *info;
 901        struct strbuf pathbuf = STRBUF_INIT;
 902
 903        /*
 904         * At the bottom of the attribute stack is the built-in
 905         * set of attribute definitions, followed by the contents
 906         * of $(prefix)/etc/gitattributes and a file specified by
 907         * core.attributesfile.  Then, contents from
 908         * .gitattribute files from directories closer to the
 909         * root to the ones in deeper directories are pushed
 910         * to the stack.  Finally, at the very top of the stack
 911         * we always keep the contents of $GIT_DIR/info/attributes.
 912         *
 913         * When checking, we use entries from near the top of the
 914         * stack, preferring $GIT_DIR/info/attributes, then
 915         * .gitattributes in deeper directories to shallower ones,
 916         * and finally use the built-in set as the default.
 917         */
 918        bootstrap_attr_stack(stack);
 919
 920        /*
 921         * Pop the "info" one that is always at the top of the stack.
 922         */
 923        info = *stack;
 924        *stack = info->prev;
 925
 926        /*
 927         * Pop the ones from directories that are not the prefix of
 928         * the path we are checking. Break out of the loop when we see
 929         * the root one (whose origin is an empty string "") or the builtin
 930         * one (whose origin is NULL) without popping it.
 931         */
 932        while ((*stack)->origin) {
 933                int namelen = (*stack)->originlen;
 934                struct attr_stack *elem;
 935
 936                elem = *stack;
 937                if (namelen <= dirlen &&
 938                    !strncmp(elem->origin, path, namelen) &&
 939                    (!namelen || path[namelen] == '/'))
 940                        break;
 941
 942                debug_pop(elem);
 943                *stack = elem->prev;
 944                attr_stack_free(elem);
 945        }
 946
 947        /*
 948         * bootstrap_attr_stack() should have added, and the
 949         * above loop should have stopped before popping, the
 950         * root element whose attr_stack->origin is set to an
 951         * empty string.
 952         */
 953        assert((*stack)->origin);
 954
 955        strbuf_addstr(&pathbuf, (*stack)->origin);
 956        /* Build up to the directory 'path' is in */
 957        while (pathbuf.len < dirlen) {
 958                size_t len = pathbuf.len;
 959                struct attr_stack *next;
 960                char *origin;
 961
 962                /* Skip path-separator */
 963                if (len < dirlen && is_dir_sep(path[len]))
 964                        len++;
 965                /* Find the end of the next component */
 966                while (len < dirlen && !is_dir_sep(path[len]))
 967                        len++;
 968
 969                if (pathbuf.len > 0)
 970                        strbuf_addch(&pathbuf, '/');
 971                strbuf_add(&pathbuf, path + pathbuf.len, (len - pathbuf.len));
 972                strbuf_addf(&pathbuf, "/%s", GITATTRIBUTES_FILE);
 973
 974                next = read_attr(pathbuf.buf, 0);
 975
 976                /* reset the pathbuf to not include "/.gitattributes" */
 977                strbuf_setlen(&pathbuf, len);
 978
 979                origin = xstrdup(pathbuf.buf);
 980                push_stack(stack, next, origin, len);
 981        }
 982
 983        /*
 984         * Finally push the "info" one at the top of the stack.
 985         */
 986        push_stack(stack, info, NULL, 0);
 987
 988        strbuf_release(&pathbuf);
 989}
 990
 991static int path_matches(const char *pathname, int pathlen,
 992                        int basename_offset,
 993                        const struct pattern *pat,
 994                        const char *base, int baselen)
 995{
 996        const char *pattern = pat->pattern;
 997        int prefix = pat->nowildcardlen;
 998        int isdir = (pathlen && pathname[pathlen - 1] == '/');
 999
1000        if ((pat->flags & EXC_FLAG_MUSTBEDIR) && !isdir)
1001                return 0;
1002
1003        if (pat->flags & EXC_FLAG_NODIR) {
1004                return match_basename(pathname + basename_offset,
1005                                      pathlen - basename_offset - isdir,
1006                                      pattern, prefix,
1007                                      pat->patternlen, pat->flags);
1008        }
1009        return match_pathname(pathname, pathlen - isdir,
1010                              base, baselen,
1011                              pattern, prefix, pat->patternlen, pat->flags);
1012}
1013
1014static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem);
1015
1016static int fill_one(const char *what, struct all_attrs_item *all_attrs,
1017                    const struct match_attr *a, int rem)
1018{
1019        int i;
1020
1021        for (i = a->num_attr - 1; rem > 0 && i >= 0; i--) {
1022                const struct git_attr *attr = a->state[i].attr;
1023                const char **n = &(all_attrs[attr->attr_nr].value);
1024                const char *v = a->state[i].setto;
1025
1026                if (*n == ATTR__UNKNOWN) {
1027                        debug_set(what,
1028                                  a->is_macro ? a->u.attr->name : a->u.pat.pattern,
1029                                  attr, v);
1030                        *n = v;
1031                        rem--;
1032                        rem = macroexpand_one(all_attrs, attr->attr_nr, rem);
1033                }
1034        }
1035        return rem;
1036}
1037
1038static int fill(const char *path, int pathlen, int basename_offset,
1039                const struct attr_stack *stack,
1040                struct all_attrs_item *all_attrs, int rem)
1041{
1042        for (; rem > 0 && stack; stack = stack->prev) {
1043                int i;
1044                const char *base = stack->origin ? stack->origin : "";
1045
1046                for (i = stack->num_matches - 1; 0 < rem && 0 <= i; i--) {
1047                        const struct match_attr *a = stack->attrs[i];
1048                        if (a->is_macro)
1049                                continue;
1050                        if (path_matches(path, pathlen, basename_offset,
1051                                         &a->u.pat, base, stack->originlen))
1052                                rem = fill_one("fill", all_attrs, a, rem);
1053                }
1054        }
1055
1056        return rem;
1057}
1058
1059static int macroexpand_one(struct all_attrs_item *all_attrs, int nr, int rem)
1060{
1061        const struct all_attrs_item *item = &all_attrs[nr];
1062
1063        if (item->macro && item->value == ATTR__TRUE)
1064                return fill_one("expand", all_attrs, item->macro, rem);
1065        else
1066                return rem;
1067}
1068
1069/*
1070 * Marks the attributes which are macros based on the attribute stack.
1071 * This prevents having to search through the attribute stack each time
1072 * a macro needs to be expanded during the fill stage.
1073 */
1074static void determine_macros(struct all_attrs_item *all_attrs,
1075                             const struct attr_stack *stack)
1076{
1077        for (; stack; stack = stack->prev) {
1078                int i;
1079                for (i = stack->num_matches - 1; i >= 0; i--) {
1080                        const struct match_attr *ma = stack->attrs[i];
1081                        if (ma->is_macro) {
1082                                int n = ma->u.attr->attr_nr;
1083                                if (!all_attrs[n].macro) {
1084                                        all_attrs[n].macro = ma;
1085                                }
1086                        }
1087                }
1088        }
1089}
1090
1091/*
1092 * Collect attributes for path into the array pointed to by check->all_attrs.
1093 * If check->check_nr is non-zero, only attributes in check[] are collected.
1094 * Otherwise all attributes are collected.
1095 */
1096static void collect_some_attrs(const char *path, struct attr_check *check)
1097{
1098        int i, pathlen, rem, dirlen;
1099        const char *cp, *last_slash = NULL;
1100        int basename_offset;
1101
1102        for (cp = path; *cp; cp++) {
1103                if (*cp == '/' && cp[1])
1104                        last_slash = cp;
1105        }
1106        pathlen = cp - path;
1107        if (last_slash) {
1108                basename_offset = last_slash + 1 - path;
1109                dirlen = last_slash - path;
1110        } else {
1111                basename_offset = 0;
1112                dirlen = 0;
1113        }
1114
1115        prepare_attr_stack(path, dirlen, &check->stack);
1116        all_attrs_init(&g_attr_hashmap, check);
1117        determine_macros(check->all_attrs, check->stack);
1118
1119        if (check->nr) {
1120                rem = 0;
1121                for (i = 0; i < check->nr; i++) {
1122                        int n = check->items[i].attr->attr_nr;
1123                        struct all_attrs_item *item = &check->all_attrs[n];
1124                        if (item->macro) {
1125                                item->value = ATTR__UNSET;
1126                                rem++;
1127                        }
1128                }
1129                if (rem == check->nr)
1130                        return;
1131        }
1132
1133        rem = check->all_attrs_nr;
1134        fill(path, pathlen, basename_offset, check->stack, check->all_attrs, rem);
1135}
1136
1137int git_check_attr(const char *path, struct attr_check *check)
1138{
1139        int i;
1140
1141        collect_some_attrs(path, check);
1142
1143        for (i = 0; i < check->nr; i++) {
1144                size_t n = check->items[i].attr->attr_nr;
1145                const char *value = check->all_attrs[n].value;
1146                if (value == ATTR__UNKNOWN)
1147                        value = ATTR__UNSET;
1148                check->items[i].value = value;
1149        }
1150
1151        return 0;
1152}
1153
1154void git_all_attrs(const char *path, struct attr_check *check)
1155{
1156        int i;
1157
1158        attr_check_reset(check);
1159        collect_some_attrs(path, check);
1160
1161        for (i = 0; i < check->all_attrs_nr; i++) {
1162                const char *name = check->all_attrs[i].attr->name;
1163                const char *value = check->all_attrs[i].value;
1164                struct attr_check_item *item;
1165                if (value == ATTR__UNSET || value == ATTR__UNKNOWN)
1166                        continue;
1167                item = attr_check_append(check, git_attr(name));
1168                item->value = value;
1169        }
1170}
1171
1172void attr_start(void)
1173{
1174#ifndef NO_PTHREADS
1175        pthread_mutex_init(&g_attr_hashmap.mutex, NULL);
1176        pthread_mutex_init(&check_vector.mutex, NULL);
1177#endif
1178}