Andrew's git / gitweb.git / grep.c
?
grep.con commit git-daemon: add tests (71039fb)
   1#include "cache.h"
   2#include "grep.h"
   3#include "userdiff.h"
   4#include "xdiff-interface.h"
   5
   6void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
   7{
   8        struct grep_pat *p = xcalloc(1, sizeof(*p));
   9        p->pattern = pat;
  10        p->patternlen = strlen(pat);
  11        p->origin = "header";
  12        p->no = 0;
  13        p->token = GREP_PATTERN_HEAD;
  14        p->field = field;
  15        *opt->header_tail = p;
  16        opt->header_tail = &p->next;
  17        p->next = NULL;
  18}
  19
  20void append_grep_pattern(struct grep_opt *opt, const char *pat,
  21                         const char *origin, int no, enum grep_pat_token t)
  22{
  23        append_grep_pat(opt, pat, strlen(pat), origin, no, t);
  24}
  25
  26void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
  27                     const char *origin, int no, enum grep_pat_token t)
  28{
  29        struct grep_pat *p = xcalloc(1, sizeof(*p));
  30        p->pattern = pat;
  31        p->patternlen = patlen;
  32        p->origin = origin;
  33        p->no = no;
  34        p->token = t;
  35        *opt->pattern_tail = p;
  36        opt->pattern_tail = &p->next;
  37        p->next = NULL;
  38}
  39
  40struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
  41{
  42        struct grep_pat *pat;
  43        struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
  44        *ret = *opt;
  45
  46        ret->pattern_list = NULL;
  47        ret->pattern_tail = &ret->pattern_list;
  48
  49        for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
  50        {
  51                if(pat->token == GREP_PATTERN_HEAD)
  52                        append_header_grep_pattern(ret, pat->field,
  53                                                   pat->pattern);
  54                else
  55                        append_grep_pat(ret, pat->pattern, pat->patternlen,
  56                                        pat->origin, pat->no, pat->token);
  57        }
  58
  59        return ret;
  60}
  61
  62static NORETURN void compile_regexp_failed(const struct grep_pat *p,
  63                const char *error)
  64{
  65        char where[1024];
  66
  67        if (p->no)
  68                sprintf(where, "In '%s' at %d, ", p->origin, p->no);
  69        else if (p->origin)
  70                sprintf(where, "%s, ", p->origin);
  71        else
  72                where[0] = 0;
  73
  74        die("%s'%s': %s", where, p->pattern, error);
  75}
  76
  77#ifdef USE_LIBPCRE
  78static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
  79{
  80        const char *error;
  81        int erroffset;
  82        int options = 0;
  83
  84        if (opt->ignore_case)
  85                options |= PCRE_CASELESS;
  86
  87        p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
  88                        NULL);
  89        if (!p->pcre_regexp)
  90                compile_regexp_failed(p, error);
  91
  92        p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
  93        if (!p->pcre_extra_info && error)
  94                die("%s", error);
  95}
  96
  97static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
  98                regmatch_t *match, int eflags)
  99{
 100        int ovector[30], ret, flags = 0;
 101
 102        if (eflags & REG_NOTBOL)
 103                flags |= PCRE_NOTBOL;
 104
 105        ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
 106                        0, flags, ovector, ARRAY_SIZE(ovector));
 107        if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
 108                die("pcre_exec failed with error code %d", ret);
 109        if (ret > 0) {
 110                ret = 0;
 111                match->rm_so = ovector[0];
 112                match->rm_eo = ovector[1];
 113        }
 114
 115        return ret;
 116}
 117
 118static void free_pcre_regexp(struct grep_pat *p)
 119{
 120        pcre_free(p->pcre_regexp);
 121        pcre_free(p->pcre_extra_info);
 122}
 123#else /* !USE_LIBPCRE */
 124static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 125{
 126        die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 127}
 128
 129static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 130                regmatch_t *match, int eflags)
 131{
 132        return 1;
 133}
 134
 135static void free_pcre_regexp(struct grep_pat *p)
 136{
 137}
 138#endif /* !USE_LIBPCRE */
 139
 140static int is_fixed(const char *s, size_t len)
 141{
 142        size_t i;
 143
 144        /* regcomp cannot accept patterns with NULs so we
 145         * consider any pattern containing a NUL fixed.
 146         */
 147        if (memchr(s, 0, len))
 148                return 1;
 149
 150        for (i = 0; i < len; i++) {
 151                if (is_regex_special(s[i]))
 152                        return 0;
 153        }
 154
 155        return 1;
 156}
 157
 158static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 159{
 160        int err;
 161
 162        p->word_regexp = opt->word_regexp;
 163        p->ignore_case = opt->ignore_case;
 164
 165        if (opt->fixed || is_fixed(p->pattern, p->patternlen))
 166                p->fixed = 1;
 167        else
 168                p->fixed = 0;
 169
 170        if (p->fixed) {
 171                if (opt->regflags & REG_ICASE || p->ignore_case) {
 172                        static char trans[256];
 173                        int i;
 174                        for (i = 0; i < 256; i++)
 175                                trans[i] = tolower(i);
 176                        p->kws = kwsalloc(trans);
 177                } else {
 178                        p->kws = kwsalloc(NULL);
 179                }
 180                kwsincr(p->kws, p->pattern, p->patternlen);
 181                kwsprep(p->kws);
 182                return;
 183        }
 184
 185        if (opt->pcre) {
 186                compile_pcre_regexp(p, opt);
 187                return;
 188        }
 189
 190        err = regcomp(&p->regexp, p->pattern, opt->regflags);
 191        if (err) {
 192                char errbuf[1024];
 193                regerror(err, &p->regexp, errbuf, 1024);
 194                regfree(&p->regexp);
 195                compile_regexp_failed(p, errbuf);
 196        }
 197}
 198
 199static struct grep_expr *compile_pattern_or(struct grep_pat **);
 200static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 201{
 202        struct grep_pat *p;
 203        struct grep_expr *x;
 204
 205        p = *list;
 206        if (!p)
 207                return NULL;
 208        switch (p->token) {
 209        case GREP_PATTERN: /* atom */
 210        case GREP_PATTERN_HEAD:
 211        case GREP_PATTERN_BODY:
 212                x = xcalloc(1, sizeof (struct grep_expr));
 213                x->node = GREP_NODE_ATOM;
 214                x->u.atom = p;
 215                *list = p->next;
 216                return x;
 217        case GREP_OPEN_PAREN:
 218                *list = p->next;
 219                x = compile_pattern_or(list);
 220                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 221                        die("unmatched parenthesis");
 222                *list = (*list)->next;
 223                return x;
 224        default:
 225                return NULL;
 226        }
 227}
 228
 229static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 230{
 231        struct grep_pat *p;
 232        struct grep_expr *x;
 233
 234        p = *list;
 235        if (!p)
 236                return NULL;
 237        switch (p->token) {
 238        case GREP_NOT:
 239                if (!p->next)
 240                        die("--not not followed by pattern expression");
 241                *list = p->next;
 242                x = xcalloc(1, sizeof (struct grep_expr));
 243                x->node = GREP_NODE_NOT;
 244                x->u.unary = compile_pattern_not(list);
 245                if (!x->u.unary)
 246                        die("--not followed by non pattern expression");
 247                return x;
 248        default:
 249                return compile_pattern_atom(list);
 250        }
 251}
 252
 253static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 254{
 255        struct grep_pat *p;
 256        struct grep_expr *x, *y, *z;
 257
 258        x = compile_pattern_not(list);
 259        p = *list;
 260        if (p && p->token == GREP_AND) {
 261                if (!p->next)
 262                        die("--and not followed by pattern expression");
 263                *list = p->next;
 264                y = compile_pattern_and(list);
 265                if (!y)
 266                        die("--and not followed by pattern expression");
 267                z = xcalloc(1, sizeof (struct grep_expr));
 268                z->node = GREP_NODE_AND;
 269                z->u.binary.left = x;
 270                z->u.binary.right = y;
 271                return z;
 272        }
 273        return x;
 274}
 275
 276static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 277{
 278        struct grep_pat *p;
 279        struct grep_expr *x, *y, *z;
 280
 281        x = compile_pattern_and(list);
 282        p = *list;
 283        if (x && p && p->token != GREP_CLOSE_PAREN) {
 284                y = compile_pattern_or(list);
 285                if (!y)
 286                        die("not a pattern expression %s", p->pattern);
 287                z = xcalloc(1, sizeof (struct grep_expr));
 288                z->node = GREP_NODE_OR;
 289                z->u.binary.left = x;
 290                z->u.binary.right = y;
 291                return z;
 292        }
 293        return x;
 294}
 295
 296static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 297{
 298        return compile_pattern_or(list);
 299}
 300
 301static struct grep_expr *grep_true_expr(void)
 302{
 303        struct grep_expr *z = xcalloc(1, sizeof(*z));
 304        z->node = GREP_NODE_TRUE;
 305        return z;
 306}
 307
 308static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 309{
 310        struct grep_expr *z = xcalloc(1, sizeof(*z));
 311        z->node = GREP_NODE_OR;
 312        z->u.binary.left = left;
 313        z->u.binary.right = right;
 314        return z;
 315}
 316
 317static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 318{
 319        struct grep_pat *p;
 320        struct grep_expr *header_expr;
 321        struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 322        enum grep_header_field fld;
 323
 324        if (!opt->header_list)
 325                return NULL;
 326        p = opt->header_list;
 327        for (p = opt->header_list; p; p = p->next) {
 328                if (p->token != GREP_PATTERN_HEAD)
 329                        die("bug: a non-header pattern in grep header list.");
 330                if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
 331                        die("bug: unknown header field %d", p->field);
 332                compile_regexp(p, opt);
 333        }
 334
 335        for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 336                header_group[fld] = NULL;
 337
 338        for (p = opt->header_list; p; p = p->next) {
 339                struct grep_expr *h;
 340                struct grep_pat *pp = p;
 341
 342                h = compile_pattern_atom(&pp);
 343                if (!h || pp != p->next)
 344                        die("bug: malformed header expr");
 345                if (!header_group[p->field]) {
 346                        header_group[p->field] = h;
 347                        continue;
 348                }
 349                header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 350        }
 351
 352        header_expr = NULL;
 353
 354        for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 355                if (!header_group[fld])
 356                        continue;
 357                if (!header_expr)
 358                        header_expr = grep_true_expr();
 359                header_expr = grep_or_expr(header_group[fld], header_expr);
 360        }
 361        return header_expr;
 362}
 363
 364void compile_grep_patterns(struct grep_opt *opt)
 365{
 366        struct grep_pat *p;
 367        struct grep_expr *header_expr = prep_header_patterns(opt);
 368
 369        for (p = opt->pattern_list; p; p = p->next) {
 370                switch (p->token) {
 371                case GREP_PATTERN: /* atom */
 372                case GREP_PATTERN_HEAD:
 373                case GREP_PATTERN_BODY:
 374                        compile_regexp(p, opt);
 375                        break;
 376                default:
 377                        opt->extended = 1;
 378                        break;
 379                }
 380        }
 381
 382        if (opt->all_match || header_expr)
 383                opt->extended = 1;
 384        else if (!opt->extended)
 385                return;
 386
 387        p = opt->pattern_list;
 388        if (p)
 389                opt->pattern_expression = compile_pattern_expr(&p);
 390        if (p)
 391                die("incomplete pattern expression: %s", p->pattern);
 392
 393        if (!header_expr)
 394                return;
 395
 396        if (!opt->pattern_expression)
 397                opt->pattern_expression = header_expr;
 398        else
 399                opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 400                                                       header_expr);
 401        opt->all_match = 1;
 402}
 403
 404static void free_pattern_expr(struct grep_expr *x)
 405{
 406        switch (x->node) {
 407        case GREP_NODE_TRUE:
 408        case GREP_NODE_ATOM:
 409                break;
 410        case GREP_NODE_NOT:
 411                free_pattern_expr(x->u.unary);
 412                break;
 413        case GREP_NODE_AND:
 414        case GREP_NODE_OR:
 415                free_pattern_expr(x->u.binary.left);
 416                free_pattern_expr(x->u.binary.right);
 417                break;
 418        }
 419        free(x);
 420}
 421
 422void free_grep_patterns(struct grep_opt *opt)
 423{
 424        struct grep_pat *p, *n;
 425
 426        for (p = opt->pattern_list; p; p = n) {
 427                n = p->next;
 428                switch (p->token) {
 429                case GREP_PATTERN: /* atom */
 430                case GREP_PATTERN_HEAD:
 431                case GREP_PATTERN_BODY:
 432                        if (p->kws)
 433                                kwsfree(p->kws);
 434                        else if (p->pcre_regexp)
 435                                free_pcre_regexp(p);
 436                        else
 437                                regfree(&p->regexp);
 438                        break;
 439                default:
 440                        break;
 441                }
 442                free(p);
 443        }
 444
 445        if (!opt->extended)
 446                return;
 447        free_pattern_expr(opt->pattern_expression);
 448}
 449
 450static char *end_of_line(char *cp, unsigned long *left)
 451{
 452        unsigned long l = *left;
 453        while (l && *cp != '\n') {
 454                l--;
 455                cp++;
 456        }
 457        *left = l;
 458        return cp;
 459}
 460
 461static int word_char(char ch)
 462{
 463        return isalnum(ch) || ch == '_';
 464}
 465
 466static void output_color(struct grep_opt *opt, const void *data, size_t size,
 467                         const char *color)
 468{
 469        if (want_color(opt->color) && color && color[0]) {
 470                opt->output(opt, color, strlen(color));
 471                opt->output(opt, data, size);
 472                opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 473        } else
 474                opt->output(opt, data, size);
 475}
 476
 477static void output_sep(struct grep_opt *opt, char sign)
 478{
 479        if (opt->null_following_name)
 480                opt->output(opt, "\0", 1);
 481        else
 482                output_color(opt, &sign, 1, opt->color_sep);
 483}
 484
 485static void show_name(struct grep_opt *opt, const char *name)
 486{
 487        output_color(opt, name, strlen(name), opt->color_filename);
 488        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 489}
 490
 491static int fixmatch(struct grep_pat *p, char *line, char *eol,
 492                    regmatch_t *match)
 493{
 494        struct kwsmatch kwsm;
 495        size_t offset = kwsexec(p->kws, line, eol - line, &kwsm);
 496        if (offset == -1) {
 497                match->rm_so = match->rm_eo = -1;
 498                return REG_NOMATCH;
 499        } else {
 500                match->rm_so = offset;
 501                match->rm_eo = match->rm_so + kwsm.size[0];
 502                return 0;
 503        }
 504}
 505
 506static int regmatch(const regex_t *preg, char *line, char *eol,
 507                    regmatch_t *match, int eflags)
 508{
 509#ifdef REG_STARTEND
 510        match->rm_so = 0;
 511        match->rm_eo = eol - line;
 512        eflags |= REG_STARTEND;
 513#endif
 514        return regexec(preg, line, 1, match, eflags);
 515}
 516
 517static int patmatch(struct grep_pat *p, char *line, char *eol,
 518                    regmatch_t *match, int eflags)
 519{
 520        int hit;
 521
 522        if (p->fixed)
 523                hit = !fixmatch(p, line, eol, match);
 524        else if (p->pcre_regexp)
 525                hit = !pcrematch(p, line, eol, match, eflags);
 526        else
 527                hit = !regmatch(&p->regexp, line, eol, match, eflags);
 528
 529        return hit;
 530}
 531
 532static int strip_timestamp(char *bol, char **eol_p)
 533{
 534        char *eol = *eol_p;
 535        int ch;
 536
 537        while (bol < --eol) {
 538                if (*eol != '>')
 539                        continue;
 540                *eol_p = ++eol;
 541                ch = *eol;
 542                *eol = '\0';
 543                return ch;
 544        }
 545        return 0;
 546}
 547
 548static struct {
 549        const char *field;
 550        size_t len;
 551} header_field[] = {
 552        { "author ", 7 },
 553        { "committer ", 10 },
 554};
 555
 556static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 557                             enum grep_context ctx,
 558                             regmatch_t *pmatch, int eflags)
 559{
 560        int hit = 0;
 561        int saved_ch = 0;
 562        const char *start = bol;
 563
 564        if ((p->token != GREP_PATTERN) &&
 565            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 566                return 0;
 567
 568        if (p->token == GREP_PATTERN_HEAD) {
 569                const char *field;
 570                size_t len;
 571                assert(p->field < ARRAY_SIZE(header_field));
 572                field = header_field[p->field].field;
 573                len = header_field[p->field].len;
 574                if (strncmp(bol, field, len))
 575                        return 0;
 576                bol += len;
 577                saved_ch = strip_timestamp(bol, &eol);
 578        }
 579
 580 again:
 581        hit = patmatch(p, bol, eol, pmatch, eflags);
 582
 583        if (hit && p->word_regexp) {
 584                if ((pmatch[0].rm_so < 0) ||
 585                    (eol - bol) < pmatch[0].rm_so ||
 586                    (pmatch[0].rm_eo < 0) ||
 587                    (eol - bol) < pmatch[0].rm_eo)
 588                        die("regexp returned nonsense");
 589
 590                /* Match beginning must be either beginning of the
 591                 * line, or at word boundary (i.e. the last char must
 592                 * not be a word char).  Similarly, match end must be
 593                 * either end of the line, or at word boundary
 594                 * (i.e. the next char must not be a word char).
 595                 */
 596                if ( ((pmatch[0].rm_so == 0) ||
 597                      !word_char(bol[pmatch[0].rm_so-1])) &&
 598                     ((pmatch[0].rm_eo == (eol-bol)) ||
 599                      !word_char(bol[pmatch[0].rm_eo])) )
 600                        ;
 601                else
 602                        hit = 0;
 603
 604                /* Words consist of at least one character. */
 605                if (pmatch->rm_so == pmatch->rm_eo)
 606                        hit = 0;
 607
 608                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 609                        /* There could be more than one match on the
 610                         * line, and the first match might not be
 611                         * strict word match.  But later ones could be!
 612                         * Forward to the next possible start, i.e. the
 613                         * next position following a non-word char.
 614                         */
 615                        bol = pmatch[0].rm_so + bol + 1;
 616                        while (word_char(bol[-1]) && bol < eol)
 617                                bol++;
 618                        eflags |= REG_NOTBOL;
 619                        if (bol < eol)
 620                                goto again;
 621                }
 622        }
 623        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 624                *eol = saved_ch;
 625        if (hit) {
 626                pmatch[0].rm_so += bol - start;
 627                pmatch[0].rm_eo += bol - start;
 628        }
 629        return hit;
 630}
 631
 632static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 633                           enum grep_context ctx, int collect_hits)
 634{
 635        int h = 0;
 636        regmatch_t match;
 637
 638        if (!x)
 639                die("Not a valid grep expression");
 640        switch (x->node) {
 641        case GREP_NODE_TRUE:
 642                h = 1;
 643                break;
 644        case GREP_NODE_ATOM:
 645                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 646                break;
 647        case GREP_NODE_NOT:
 648                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 649                break;
 650        case GREP_NODE_AND:
 651                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 652                        return 0;
 653                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 654                break;
 655        case GREP_NODE_OR:
 656                if (!collect_hits)
 657                        return (match_expr_eval(x->u.binary.left,
 658                                                bol, eol, ctx, 0) ||
 659                                match_expr_eval(x->u.binary.right,
 660                                                bol, eol, ctx, 0));
 661                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 662                x->u.binary.left->hit |= h;
 663                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 664                break;
 665        default:
 666                die("Unexpected node type (internal error) %d", x->node);
 667        }
 668        if (collect_hits)
 669                x->hit |= h;
 670        return h;
 671}
 672
 673static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 674                      enum grep_context ctx, int collect_hits)
 675{
 676        struct grep_expr *x = opt->pattern_expression;
 677        return match_expr_eval(x, bol, eol, ctx, collect_hits);
 678}
 679
 680static int match_line(struct grep_opt *opt, char *bol, char *eol,
 681                      enum grep_context ctx, int collect_hits)
 682{
 683        struct grep_pat *p;
 684        regmatch_t match;
 685
 686        if (opt->extended)
 687                return match_expr(opt, bol, eol, ctx, collect_hits);
 688
 689        /* we do not call with collect_hits without being extended */
 690        for (p = opt->pattern_list; p; p = p->next) {
 691                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 692                        return 1;
 693        }
 694        return 0;
 695}
 696
 697static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 698                              enum grep_context ctx,
 699                              regmatch_t *pmatch, int eflags)
 700{
 701        regmatch_t match;
 702
 703        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 704                return 0;
 705        if (match.rm_so < 0 || match.rm_eo < 0)
 706                return 0;
 707        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 708                if (match.rm_so > pmatch->rm_so)
 709                        return 1;
 710                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 711                        return 1;
 712        }
 713        pmatch->rm_so = match.rm_so;
 714        pmatch->rm_eo = match.rm_eo;
 715        return 1;
 716}
 717
 718static int next_match(struct grep_opt *opt, char *bol, char *eol,
 719                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 720{
 721        struct grep_pat *p;
 722        int hit = 0;
 723
 724        pmatch->rm_so = pmatch->rm_eo = -1;
 725        if (bol < eol) {
 726                for (p = opt->pattern_list; p; p = p->next) {
 727                        switch (p->token) {
 728                        case GREP_PATTERN: /* atom */
 729                        case GREP_PATTERN_HEAD:
 730                        case GREP_PATTERN_BODY:
 731                                hit |= match_next_pattern(p, bol, eol, ctx,
 732                                                          pmatch, eflags);
 733                                break;
 734                        default:
 735                                break;
 736                        }
 737                }
 738        }
 739        return hit;
 740}
 741
 742static void show_line(struct grep_opt *opt, char *bol, char *eol,
 743                      const char *name, unsigned lno, char sign)
 744{
 745        int rest = eol - bol;
 746        char *line_color = NULL;
 747
 748        if (opt->file_break && opt->last_shown == 0) {
 749                if (opt->show_hunk_mark)
 750                        opt->output(opt, "\n", 1);
 751        } else if (opt->pre_context || opt->post_context || opt->funcbody) {
 752                if (opt->last_shown == 0) {
 753                        if (opt->show_hunk_mark) {
 754                                output_color(opt, "--", 2, opt->color_sep);
 755                                opt->output(opt, "\n", 1);
 756                        }
 757                } else if (lno > opt->last_shown + 1) {
 758                        output_color(opt, "--", 2, opt->color_sep);
 759                        opt->output(opt, "\n", 1);
 760                }
 761        }
 762        if (opt->heading && opt->last_shown == 0) {
 763                output_color(opt, name, strlen(name), opt->color_filename);
 764                opt->output(opt, "\n", 1);
 765        }
 766        opt->last_shown = lno;
 767
 768        if (!opt->heading && opt->pathname) {
 769                output_color(opt, name, strlen(name), opt->color_filename);
 770                output_sep(opt, sign);
 771        }
 772        if (opt->linenum) {
 773                char buf[32];
 774                snprintf(buf, sizeof(buf), "%d", lno);
 775                output_color(opt, buf, strlen(buf), opt->color_lineno);
 776                output_sep(opt, sign);
 777        }
 778        if (opt->color) {
 779                regmatch_t match;
 780                enum grep_context ctx = GREP_CONTEXT_BODY;
 781                int ch = *eol;
 782                int eflags = 0;
 783
 784                if (sign == ':')
 785                        line_color = opt->color_selected;
 786                else if (sign == '-')
 787                        line_color = opt->color_context;
 788                else if (sign == '=')
 789                        line_color = opt->color_function;
 790                *eol = '\0';
 791                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 792                        if (match.rm_so == match.rm_eo)
 793                                break;
 794
 795                        output_color(opt, bol, match.rm_so, line_color);
 796                        output_color(opt, bol + match.rm_so,
 797                                     match.rm_eo - match.rm_so,
 798                                     opt->color_match);
 799                        bol += match.rm_eo;
 800                        rest -= match.rm_eo;
 801                        eflags = REG_NOTBOL;
 802                }
 803                *eol = ch;
 804        }
 805        output_color(opt, bol, rest, line_color);
 806        opt->output(opt, "\n", 1);
 807}
 808
 809#ifndef NO_PTHREADS
 810/*
 811 * This lock protects access to the gitattributes machinery, which is
 812 * not thread-safe.
 813 */
 814pthread_mutex_t grep_attr_mutex;
 815
 816static inline void grep_attr_lock(struct grep_opt *opt)
 817{
 818        if (opt->use_threads)
 819                pthread_mutex_lock(&grep_attr_mutex);
 820}
 821
 822static inline void grep_attr_unlock(struct grep_opt *opt)
 823{
 824        if (opt->use_threads)
 825                pthread_mutex_unlock(&grep_attr_mutex);
 826}
 827#else
 828#define grep_attr_lock(opt)
 829#define grep_attr_unlock(opt)
 830#endif
 831
 832static int match_funcname(struct grep_opt *opt, const char *name, char *bol, char *eol)
 833{
 834        xdemitconf_t *xecfg = opt->priv;
 835        if (xecfg && !xecfg->find_func) {
 836                struct userdiff_driver *drv;
 837                grep_attr_lock(opt);
 838                drv = userdiff_find_by_path(name);
 839                grep_attr_unlock(opt);
 840                if (drv && drv->funcname.pattern) {
 841                        const struct userdiff_funcname *pe = &drv->funcname;
 842                        xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
 843                } else {
 844                        xecfg = opt->priv = NULL;
 845                }
 846        }
 847
 848        if (xecfg) {
 849                char buf[1];
 850                return xecfg->find_func(bol, eol - bol, buf, 1,
 851                                        xecfg->find_func_priv) >= 0;
 852        }
 853
 854        if (bol == eol)
 855                return 0;
 856        if (isalpha(*bol) || *bol == '_' || *bol == '$')
 857                return 1;
 858        return 0;
 859}
 860
 861static void show_funcname_line(struct grep_opt *opt, const char *name,
 862                               char *buf, char *bol, unsigned lno)
 863{
 864        while (bol > buf) {
 865                char *eol = --bol;
 866
 867                while (bol > buf && bol[-1] != '\n')
 868                        bol--;
 869                lno--;
 870
 871                if (lno <= opt->last_shown)
 872                        break;
 873
 874                if (match_funcname(opt, name, bol, eol)) {
 875                        show_line(opt, bol, eol, name, lno, '=');
 876                        break;
 877                }
 878        }
 879}
 880
 881static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 882                             char *bol, char *end, unsigned lno)
 883{
 884        unsigned cur = lno, from = 1, funcname_lno = 0;
 885        int funcname_needed = !!opt->funcname;
 886
 887        if (opt->funcbody && !match_funcname(opt, name, bol, end))
 888                funcname_needed = 2;
 889
 890        if (opt->pre_context < lno)
 891                from = lno - opt->pre_context;
 892        if (from <= opt->last_shown)
 893                from = opt->last_shown + 1;
 894
 895        /* Rewind. */
 896        while (bol > buf &&
 897               cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
 898                char *eol = --bol;
 899
 900                while (bol > buf && bol[-1] != '\n')
 901                        bol--;
 902                cur--;
 903                if (funcname_needed && match_funcname(opt, name, bol, eol)) {
 904                        funcname_lno = cur;
 905                        funcname_needed = 0;
 906                }
 907        }
 908
 909        /* We need to look even further back to find a function signature. */
 910        if (opt->funcname && funcname_needed)
 911                show_funcname_line(opt, name, buf, bol, cur);
 912
 913        /* Back forward. */
 914        while (cur < lno) {
 915                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 916
 917                while (*eol != '\n')
 918                        eol++;
 919                show_line(opt, bol, eol, name, cur, sign);
 920                bol = eol + 1;
 921                cur++;
 922        }
 923}
 924
 925static int should_lookahead(struct grep_opt *opt)
 926{
 927        struct grep_pat *p;
 928
 929        if (opt->extended)
 930                return 0; /* punt for too complex stuff */
 931        if (opt->invert)
 932                return 0;
 933        for (p = opt->pattern_list; p; p = p->next) {
 934                if (p->token != GREP_PATTERN)
 935                        return 0; /* punt for "header only" and stuff */
 936        }
 937        return 1;
 938}
 939
 940static int look_ahead(struct grep_opt *opt,
 941                      unsigned long *left_p,
 942                      unsigned *lno_p,
 943                      char **bol_p)
 944{
 945        unsigned lno = *lno_p;
 946        char *bol = *bol_p;
 947        struct grep_pat *p;
 948        char *sp, *last_bol;
 949        regoff_t earliest = -1;
 950
 951        for (p = opt->pattern_list; p; p = p->next) {
 952                int hit;
 953                regmatch_t m;
 954
 955                hit = patmatch(p, bol, bol + *left_p, &m, 0);
 956                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 957                        continue;
 958                if (earliest < 0 || m.rm_so < earliest)
 959                        earliest = m.rm_so;
 960        }
 961
 962        if (earliest < 0) {
 963                *bol_p = bol + *left_p;
 964                *left_p = 0;
 965                return 1;
 966        }
 967        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 968                ; /* find the beginning of the line */
 969        last_bol = sp;
 970
 971        for (sp = bol; sp < last_bol; sp++) {
 972                if (*sp == '\n')
 973                        lno++;
 974        }
 975        *left_p -= last_bol - bol;
 976        *bol_p = last_bol;
 977        *lno_p = lno;
 978        return 0;
 979}
 980
 981static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 982{
 983        fwrite(buf, size, 1, stdout);
 984}
 985
 986static int grep_buffer_1(struct grep_opt *opt, const char *name,
 987                         char *buf, unsigned long size, int collect_hits)
 988{
 989        char *bol = buf;
 990        unsigned long left = size;
 991        unsigned lno = 1;
 992        unsigned last_hit = 0;
 993        int binary_match_only = 0;
 994        unsigned count = 0;
 995        int try_lookahead = 0;
 996        int show_function = 0;
 997        enum grep_context ctx = GREP_CONTEXT_HEAD;
 998        xdemitconf_t xecfg;
 999
1000        if (!opt->output)
1001                opt->output = std_output;
1002
1003        if (opt->pre_context || opt->post_context || opt->file_break ||
1004            opt->funcbody) {
1005                /* Show hunk marks, except for the first file. */
1006                if (opt->last_shown)
1007                        opt->show_hunk_mark = 1;
1008                /*
1009                 * If we're using threads then we can't easily identify
1010                 * the first file.  Always put hunk marks in that case
1011                 * and skip the very first one later in work_done().
1012                 */
1013                if (opt->output != std_output)
1014                        opt->show_hunk_mark = 1;
1015        }
1016        opt->last_shown = 0;
1017
1018        switch (opt->binary) {
1019        case GREP_BINARY_DEFAULT:
1020                if (buffer_is_binary(buf, size))
1021                        binary_match_only = 1;
1022                break;
1023        case GREP_BINARY_NOMATCH:
1024                if (buffer_is_binary(buf, size))
1025                        return 0; /* Assume unmatch */
1026                break;
1027        case GREP_BINARY_TEXT:
1028                break;
1029        default:
1030                die("bug: unknown binary handling mode");
1031        }
1032
1033        memset(&xecfg, 0, sizeof(xecfg));
1034        opt->priv = &xecfg;
1035
1036        try_lookahead = should_lookahead(opt);
1037
1038        while (left) {
1039                char *eol, ch;
1040                int hit;
1041
1042                /*
1043                 * look_ahead() skips quickly to the line that possibly
1044                 * has the next hit; don't call it if we need to do
1045                 * something more than just skipping the current line
1046                 * in response to an unmatch for the current line.  E.g.
1047                 * inside a post-context window, we will show the current
1048                 * line as a context around the previous hit when it
1049                 * doesn't hit.
1050                 */
1051                if (try_lookahead
1052                    && !(last_hit
1053                         && (show_function ||
1054                             lno <= last_hit + opt->post_context))
1055                    && look_ahead(opt, &left, &lno, &bol))
1056                        break;
1057                eol = end_of_line(bol, &left);
1058                ch = *eol;
1059                *eol = 0;
1060
1061                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1062                        ctx = GREP_CONTEXT_BODY;
1063
1064                hit = match_line(opt, bol, eol, ctx, collect_hits);
1065                *eol = ch;
1066
1067                if (collect_hits)
1068                        goto next_line;
1069
1070                /* "grep -v -e foo -e bla" should list lines
1071                 * that do not have either, so inversion should
1072                 * be done outside.
1073                 */
1074                if (opt->invert)
1075                        hit = !hit;
1076                if (opt->unmatch_name_only) {
1077                        if (hit)
1078                                return 0;
1079                        goto next_line;
1080                }
1081                if (hit) {
1082                        count++;
1083                        if (opt->status_only)
1084                                return 1;
1085                        if (opt->name_only) {
1086                                show_name(opt, name);
1087                                return 1;
1088                        }
1089                        if (opt->count)
1090                                goto next_line;
1091                        if (binary_match_only) {
1092                                opt->output(opt, "Binary file ", 12);
1093                                output_color(opt, name, strlen(name),
1094                                             opt->color_filename);
1095                                opt->output(opt, " matches\n", 9);
1096                                return 1;
1097                        }
1098                        /* Hit at this line.  If we haven't shown the
1099                         * pre-context lines, we would need to show them.
1100                         */
1101                        if (opt->pre_context || opt->funcbody)
1102                                show_pre_context(opt, name, buf, bol, eol, lno);
1103                        else if (opt->funcname)
1104                                show_funcname_line(opt, name, buf, bol, lno);
1105                        show_line(opt, bol, eol, name, lno, ':');
1106                        last_hit = lno;
1107                        if (opt->funcbody)
1108                                show_function = 1;
1109                        goto next_line;
1110                }
1111                if (show_function && match_funcname(opt, name, bol, eol))
1112                        show_function = 0;
1113                if (show_function ||
1114                    (last_hit && lno <= last_hit + opt->post_context)) {
1115                        /* If the last hit is within the post context,
1116                         * we need to show this line.
1117                         */
1118                        show_line(opt, bol, eol, name, lno, '-');
1119                }
1120
1121        next_line:
1122                bol = eol + 1;
1123                if (!left)
1124                        break;
1125                left--;
1126                lno++;
1127        }
1128
1129        if (collect_hits)
1130                return 0;
1131
1132        if (opt->status_only)
1133                return 0;
1134        if (opt->unmatch_name_only) {
1135                /* We did not see any hit, so we want to show this */
1136                show_name(opt, name);
1137                return 1;
1138        }
1139
1140        xdiff_clear_find_func(&xecfg);
1141        opt->priv = NULL;
1142
1143        /* NEEDSWORK:
1144         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1145         * which feels mostly useless but sometimes useful.  Maybe
1146         * make it another option?  For now suppress them.
1147         */
1148        if (opt->count && count) {
1149                char buf[32];
1150                output_color(opt, name, strlen(name), opt->color_filename);
1151                output_sep(opt, ':');
1152                snprintf(buf, sizeof(buf), "%u\n", count);
1153                opt->output(opt, buf, strlen(buf));
1154                return 1;
1155        }
1156        return !!last_hit;
1157}
1158
1159static void clr_hit_marker(struct grep_expr *x)
1160{
1161        /* All-hit markers are meaningful only at the very top level
1162         * OR node.
1163         */
1164        while (1) {
1165                x->hit = 0;
1166                if (x->node != GREP_NODE_OR)
1167                        return;
1168                x->u.binary.left->hit = 0;
1169                x = x->u.binary.right;
1170        }
1171}
1172
1173static int chk_hit_marker(struct grep_expr *x)
1174{
1175        /* Top level nodes have hit markers.  See if they all are hits */
1176        while (1) {
1177                if (x->node != GREP_NODE_OR)
1178                        return x->hit;
1179                if (!x->u.binary.left->hit)
1180                        return 0;
1181                x = x->u.binary.right;
1182        }
1183}
1184
1185int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
1186{
1187        /*
1188         * we do not have to do the two-pass grep when we do not check
1189         * buffer-wide "all-match".
1190         */
1191        if (!opt->all_match)
1192                return grep_buffer_1(opt, name, buf, size, 0);
1193
1194        /* Otherwise the toplevel "or" terms hit a bit differently.
1195         * We first clear hit markers from them.
1196         */
1197        clr_hit_marker(opt->pattern_expression);
1198        grep_buffer_1(opt, name, buf, size, 1);
1199
1200        if (!chk_hit_marker(opt->pattern_expression))
1201                return 0;
1202
1203        return grep_buffer_1(opt, name, buf, size, 0);
1204}