Andrew's git / gitweb.git / attr.c
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attr.con commit Merge branch 'gp/branch' (5c088a2)
   1#include "cache.h"
   2#include "attr.h"
   3
   4const char git_attr__true[] = "(builtin)true";
   5const char git_attr__false[] = "\0(builtin)false";
   6static const char git_attr__unknown[] = "(builtin)unknown";
   7#define ATTR__TRUE git_attr__true
   8#define ATTR__FALSE git_attr__false
   9#define ATTR__UNSET NULL
  10#define ATTR__UNKNOWN git_attr__unknown
  11
  12/*
  13 * The basic design decision here is that we are not going to have
  14 * insanely large number of attributes.
  15 *
  16 * This is a randomly chosen prime.
  17 */
  18#define HASHSIZE 257
  19
  20#ifndef DEBUG_ATTR
  21#define DEBUG_ATTR 0
  22#endif
  23
  24struct git_attr {
  25        struct git_attr *next;
  26        unsigned h;
  27        int attr_nr;
  28        char name[FLEX_ARRAY];
  29};
  30static int attr_nr;
  31
  32static struct git_attr_check *check_all_attr;
  33static struct git_attr *(git_attr_hash[HASHSIZE]);
  34
  35static unsigned hash_name(const char *name, int namelen)
  36{
  37        unsigned val = 0;
  38        unsigned char c;
  39
  40        while (namelen--) {
  41                c = *name++;
  42                val = ((val << 7) | (val >> 22)) ^ c;
  43        }
  44        return val;
  45}
  46
  47static int invalid_attr_name(const char *name, int namelen)
  48{
  49        /*
  50         * Attribute name cannot begin with '-' and from
  51         * [-A-Za-z0-9_.].  We'd specifically exclude '=' for now,
  52         * as we might later want to allow non-binary value for
  53         * attributes, e.g. "*.svg      merge=special-merge-program-for-svg"
  54         */
  55        if (*name == '-')
  56                return -1;
  57        while (namelen--) {
  58                char ch = *name++;
  59                if (! (ch == '-' || ch == '.' || ch == '_' ||
  60                       ('0' <= ch && ch <= '9') ||
  61                       ('a' <= ch && ch <= 'z') ||
  62                       ('A' <= ch && ch <= 'Z')) )
  63                        return -1;
  64        }
  65        return 0;
  66}
  67
  68struct git_attr *git_attr(const char *name, int len)
  69{
  70        unsigned hval = hash_name(name, len);
  71        unsigned pos = hval % HASHSIZE;
  72        struct git_attr *a;
  73
  74        for (a = git_attr_hash[pos]; a; a = a->next) {
  75                if (a->h == hval &&
  76                    !memcmp(a->name, name, len) && !a->name[len])
  77                        return a;
  78        }
  79
  80        if (invalid_attr_name(name, len))
  81                return NULL;
  82
  83        a = xmalloc(sizeof(*a) + len + 1);
  84        memcpy(a->name, name, len);
  85        a->name[len] = 0;
  86        a->h = hval;
  87        a->next = git_attr_hash[pos];
  88        a->attr_nr = attr_nr++;
  89        git_attr_hash[pos] = a;
  90
  91        check_all_attr = xrealloc(check_all_attr,
  92                                  sizeof(*check_all_attr) * attr_nr);
  93        check_all_attr[a->attr_nr].attr = a;
  94        check_all_attr[a->attr_nr].value = ATTR__UNKNOWN;
  95        return a;
  96}
  97
  98/*
  99 * .gitattributes file is one line per record, each of which is
 100 *
 101 * (1) glob pattern.
 102 * (2) whitespace
 103 * (3) whitespace separated list of attribute names, each of which
 104 *     could be prefixed with '-' to mean "set to false", '!' to mean
 105 *     "unset".
 106 */
 107
 108/* What does a matched pattern decide? */
 109struct attr_state {
 110        struct git_attr *attr;
 111        const char *setto;
 112};
 113
 114struct match_attr {
 115        union {
 116                char *pattern;
 117                struct git_attr *attr;
 118        } u;
 119        char is_macro;
 120        unsigned num_attr;
 121        struct attr_state state[FLEX_ARRAY];
 122};
 123
 124static const char blank[] = " \t\r\n";
 125
 126static const char *parse_attr(const char *src, int lineno, const char *cp,
 127                              int *num_attr, struct match_attr *res)
 128{
 129        const char *ep, *equals;
 130        int len;
 131
 132        ep = cp + strcspn(cp, blank);
 133        equals = strchr(cp, '=');
 134        if (equals && ep < equals)
 135                equals = NULL;
 136        if (equals)
 137                len = equals - cp;
 138        else
 139                len = ep - cp;
 140        if (!res) {
 141                if (*cp == '-' || *cp == '!') {
 142                        cp++;
 143                        len--;
 144                }
 145                if (invalid_attr_name(cp, len)) {
 146                        fprintf(stderr,
 147                                "%.*s is not a valid attribute name: %s:%d\n",
 148                                len, cp, src, lineno);
 149                        return NULL;
 150                }
 151        } else {
 152                struct attr_state *e;
 153
 154                e = &(res->state[*num_attr]);
 155                if (*cp == '-' || *cp == '!') {
 156                        e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
 157                        cp++;
 158                        len--;
 159                }
 160                else if (!equals)
 161                        e->setto = ATTR__TRUE;
 162                else {
 163                        char *value;
 164                        int vallen = ep - equals;
 165                        value = xmalloc(vallen);
 166                        memcpy(value, equals+1, vallen-1);
 167                        value[vallen-1] = 0;
 168                        e->setto = value;
 169                }
 170                e->attr = git_attr(cp, len);
 171        }
 172        (*num_attr)++;
 173        return ep + strspn(ep, blank);
 174}
 175
 176static struct match_attr *parse_attr_line(const char *line, const char *src,
 177                                          int lineno, int macro_ok)
 178{
 179        int namelen;
 180        int num_attr;
 181        const char *cp, *name;
 182        struct match_attr *res = NULL;
 183        int pass;
 184        int is_macro;
 185
 186        cp = line + strspn(line, blank);
 187        if (!*cp || *cp == '#')
 188                return NULL;
 189        name = cp;
 190        namelen = strcspn(name, blank);
 191        if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
 192            !prefixcmp(name, ATTRIBUTE_MACRO_PREFIX)) {
 193                if (!macro_ok) {
 194                        fprintf(stderr, "%s not allowed: %s:%d\n",
 195                                name, src, lineno);
 196                        return NULL;
 197                }
 198                is_macro = 1;
 199                name += strlen(ATTRIBUTE_MACRO_PREFIX);
 200                name += strspn(name, blank);
 201                namelen = strcspn(name, blank);
 202                if (invalid_attr_name(name, namelen)) {
 203                        fprintf(stderr,
 204                                "%.*s is not a valid attribute name: %s:%d\n",
 205                                namelen, name, src, lineno);
 206                        return NULL;
 207                }
 208        }
 209        else
 210                is_macro = 0;
 211
 212        for (pass = 0; pass < 2; pass++) {
 213                /* pass 0 counts and allocates, pass 1 fills */
 214                num_attr = 0;
 215                cp = name + namelen;
 216                cp = cp + strspn(cp, blank);
 217                while (*cp)
 218                        cp = parse_attr(src, lineno, cp, &num_attr, res);
 219                if (pass)
 220                        break;
 221                res = xcalloc(1,
 222                              sizeof(*res) +
 223                              sizeof(struct attr_state) * num_attr +
 224                              (is_macro ? 0 : namelen + 1));
 225                if (is_macro)
 226                        res->u.attr = git_attr(name, namelen);
 227                else {
 228                        res->u.pattern = (char*)&(res->state[num_attr]);
 229                        memcpy(res->u.pattern, name, namelen);
 230                        res->u.pattern[namelen] = 0;
 231                }
 232                res->is_macro = is_macro;
 233                res->num_attr = num_attr;
 234        }
 235        return res;
 236}
 237
 238/*
 239 * Like info/exclude and .gitignore, the attribute information can
 240 * come from many places.
 241 *
 242 * (1) .gitattribute file of the same directory;
 243 * (2) .gitattribute file of the parent directory if (1) does not have
 244 *      any match; this goes recursively upwards, just like .gitignore.
 245 * (3) $GIT_DIR/info/attributes, which overrides both of the above.
 246 *
 247 * In the same file, later entries override the earlier match, so in the
 248 * global list, we would have entries from info/attributes the earliest
 249 * (reading the file from top to bottom), .gitattribute of the root
 250 * directory (again, reading the file from top to bottom) down to the
 251 * current directory, and then scan the list backwards to find the first match.
 252 * This is exactly the same as what excluded() does in dir.c to deal with
 253 * .gitignore
 254 */
 255
 256static struct attr_stack {
 257        struct attr_stack *prev;
 258        char *origin;
 259        unsigned num_matches;
 260        struct match_attr **attrs;
 261} *attr_stack;
 262
 263static void free_attr_elem(struct attr_stack *e)
 264{
 265        int i;
 266        free(e->origin);
 267        for (i = 0; i < e->num_matches; i++) {
 268                struct match_attr *a = e->attrs[i];
 269                int j;
 270                for (j = 0; j < a->num_attr; j++) {
 271                        const char *setto = a->state[j].setto;
 272                        if (setto == ATTR__TRUE ||
 273                            setto == ATTR__FALSE ||
 274                            setto == ATTR__UNSET ||
 275                            setto == ATTR__UNKNOWN)
 276                                ;
 277                        else
 278                                free((char*) setto);
 279                }
 280                free(a);
 281        }
 282        free(e);
 283}
 284
 285static const char *builtin_attr[] = {
 286        "[attr]binary -diff -crlf",
 287        NULL,
 288};
 289
 290static struct attr_stack *read_attr_from_array(const char **list)
 291{
 292        struct attr_stack *res;
 293        const char *line;
 294        int lineno = 0;
 295
 296        res = xcalloc(1, sizeof(*res));
 297        while ((line = *(list++)) != NULL) {
 298                struct match_attr *a;
 299
 300                a = parse_attr_line(line, "[builtin]", ++lineno, 1);
 301                if (!a)
 302                        continue;
 303                res->attrs = xrealloc(res->attrs,
 304                        sizeof(struct match_attr *) * (res->num_matches + 1));
 305                res->attrs[res->num_matches++] = a;
 306        }
 307        return res;
 308}
 309
 310static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
 311{
 312        FILE *fp;
 313        struct attr_stack *res;
 314        char buf[2048];
 315        int lineno = 0;
 316
 317        res = xcalloc(1, sizeof(*res));
 318        fp = fopen(path, "r");
 319        if (!fp)
 320                return res;
 321
 322        while (fgets(buf, sizeof(buf), fp)) {
 323                struct match_attr *a;
 324
 325                a = parse_attr_line(buf, path, ++lineno, macro_ok);
 326                if (!a)
 327                        continue;
 328                res->attrs = xrealloc(res->attrs,
 329                        sizeof(struct match_attr *) * (res->num_matches + 1));
 330                res->attrs[res->num_matches++] = a;
 331        }
 332        fclose(fp);
 333        return res;
 334}
 335
 336#if DEBUG_ATTR
 337static void debug_info(const char *what, struct attr_stack *elem)
 338{
 339        fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
 340}
 341static void debug_set(const char *what, const char *match, struct git_attr *attr, void *v)
 342{
 343        const char *value = v;
 344
 345        if (ATTR_TRUE(value))
 346                value = "set";
 347        else if (ATTR_FALSE(value))
 348                value = "unset";
 349        else if (ATTR_UNSET(value))
 350                value = "unspecified";
 351
 352        fprintf(stderr, "%s: %s => %s (%s)\n",
 353                what, attr->name, (char *) value, match);
 354}
 355#define debug_push(a) debug_info("push", (a))
 356#define debug_pop(a) debug_info("pop", (a))
 357#else
 358#define debug_push(a) do { ; } while (0)
 359#define debug_pop(a) do { ; } while (0)
 360#define debug_set(a,b,c,d) do { ; } while (0)
 361#endif
 362
 363static void bootstrap_attr_stack(void)
 364{
 365        if (!attr_stack) {
 366                struct attr_stack *elem;
 367
 368                elem = read_attr_from_array(builtin_attr);
 369                elem->origin = NULL;
 370                elem->prev = attr_stack;
 371                attr_stack = elem;
 372
 373                elem = read_attr_from_file(GITATTRIBUTES_FILE, 1);
 374                elem->origin = strdup("");
 375                elem->prev = attr_stack;
 376                attr_stack = elem;
 377                debug_push(elem);
 378
 379                elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
 380                elem->origin = NULL;
 381                elem->prev = attr_stack;
 382                attr_stack = elem;
 383        }
 384}
 385
 386static void prepare_attr_stack(const char *path, int dirlen)
 387{
 388        struct attr_stack *elem, *info;
 389        int len;
 390        char pathbuf[PATH_MAX];
 391
 392        /*
 393         * At the bottom of the attribute stack is the built-in
 394         * set of attribute definitions.  Then, contents from
 395         * .gitattribute files from directories closer to the
 396         * root to the ones in deeper directories are pushed
 397         * to the stack.  Finally, at the very top of the stack
 398         * we always keep the contents of $GIT_DIR/info/attributes.
 399         *
 400         * When checking, we use entries from near the top of the
 401         * stack, preferring $GIT_DIR/info/attributes, then
 402         * .gitattributes in deeper directories to shallower ones,
 403         * and finally use the built-in set as the default.
 404         */
 405        if (!attr_stack)
 406                bootstrap_attr_stack();
 407
 408        /*
 409         * Pop the "info" one that is always at the top of the stack.
 410         */
 411        info = attr_stack;
 412        attr_stack = info->prev;
 413
 414        /*
 415         * Pop the ones from directories that are not the prefix of
 416         * the path we are checking.
 417         */
 418        while (attr_stack && attr_stack->origin) {
 419                int namelen = strlen(attr_stack->origin);
 420
 421                elem = attr_stack;
 422                if (namelen <= dirlen &&
 423                    !strncmp(elem->origin, path, namelen))
 424                        break;
 425
 426                debug_pop(elem);
 427                attr_stack = elem->prev;
 428                free_attr_elem(elem);
 429        }
 430
 431        /*
 432         * Read from parent directories and push them down
 433         */
 434        while (1) {
 435                char *cp;
 436
 437                len = strlen(attr_stack->origin);
 438                if (dirlen <= len)
 439                        break;
 440                memcpy(pathbuf, path, dirlen);
 441                memcpy(pathbuf + dirlen, "/", 2);
 442                cp = strchr(pathbuf + len + 1, '/');
 443                strcpy(cp + 1, GITATTRIBUTES_FILE);
 444                elem = read_attr_from_file(pathbuf, 0);
 445                *cp = '\0';
 446                elem->origin = strdup(pathbuf);
 447                elem->prev = attr_stack;
 448                attr_stack = elem;
 449                debug_push(elem);
 450        }
 451
 452        /*
 453         * Finally push the "info" one at the top of the stack.
 454         */
 455        info->prev = attr_stack;
 456        attr_stack = info;
 457}
 458
 459static int path_matches(const char *pathname, int pathlen,
 460                        const char *pattern,
 461                        const char *base, int baselen)
 462{
 463        if (!strchr(pattern, '/')) {
 464                /* match basename */
 465                const char *basename = strrchr(pathname, '/');
 466                basename = basename ? basename + 1 : pathname;
 467                return (fnmatch(pattern, basename, 0) == 0);
 468        }
 469        /*
 470         * match with FNM_PATHNAME; the pattern has base implicitly
 471         * in front of it.
 472         */
 473        if (*pattern == '/')
 474                pattern++;
 475        if (pathlen < baselen ||
 476            (baselen && pathname[baselen - 1] != '/') ||
 477            strncmp(pathname, base, baselen))
 478                return 0;
 479        return fnmatch(pattern, pathname + baselen, FNM_PATHNAME) == 0;
 480}
 481
 482static int fill_one(const char *what, struct match_attr *a, int rem)
 483{
 484        struct git_attr_check *check = check_all_attr;
 485        int i;
 486
 487        for (i = 0; 0 < rem && i < a->num_attr; i++) {
 488                struct git_attr *attr = a->state[i].attr;
 489                const char **n = &(check[attr->attr_nr].value);
 490                const char *v = a->state[i].setto;
 491
 492                if (*n == ATTR__UNKNOWN) {
 493                        debug_set(what, a->u.pattern, attr, v);
 494                        *n = v;
 495                        rem--;
 496                }
 497        }
 498        return rem;
 499}
 500
 501static int fill(const char *path, int pathlen, struct attr_stack *stk, int rem)
 502{
 503        int i;
 504        const char *base = stk->origin ? stk->origin : "";
 505
 506        for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
 507                struct match_attr *a = stk->attrs[i];
 508                if (a->is_macro)
 509                        continue;
 510                if (path_matches(path, pathlen,
 511                                 a->u.pattern, base, strlen(base)))
 512                        rem = fill_one("fill", a, rem);
 513        }
 514        return rem;
 515}
 516
 517static int macroexpand(struct attr_stack *stk, int rem)
 518{
 519        int i;
 520        struct git_attr_check *check = check_all_attr;
 521
 522        for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
 523                struct match_attr *a = stk->attrs[i];
 524                if (!a->is_macro)
 525                        continue;
 526                if (check[a->u.attr->attr_nr].value != ATTR__TRUE)
 527                        continue;
 528                rem = fill_one("expand", a, rem);
 529        }
 530        return rem;
 531}
 532
 533int git_checkattr(const char *path, int num, struct git_attr_check *check)
 534{
 535        struct attr_stack *stk;
 536        const char *cp;
 537        int dirlen, pathlen, i, rem;
 538
 539        bootstrap_attr_stack();
 540        for (i = 0; i < attr_nr; i++)
 541                check_all_attr[i].value = ATTR__UNKNOWN;
 542
 543        pathlen = strlen(path);
 544        cp = strrchr(path, '/');
 545        if (!cp)
 546                dirlen = 0;
 547        else
 548                dirlen = cp - path;
 549        prepare_attr_stack(path, dirlen);
 550        rem = attr_nr;
 551        for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
 552                rem = fill(path, pathlen, stk, rem);
 553
 554        for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
 555                rem = macroexpand(stk, rem);
 556
 557        for (i = 0; i < num; i++) {
 558                const char *value = check_all_attr[check[i].attr->attr_nr].value;
 559                if (value == ATTR__UNKNOWN)
 560                        value = ATTR__UNSET;
 561                check[i].value = value;
 562        }
 563
 564        return 0;
 565}