Andrew's git - gitweb.git/blob

c35a7ce57d323fdc1e64fdcc33f90cf977e62342
   1#include "cache.h"
   2#include "grep.h"
   3#include "userdiff.h"
   4#include "xdiff-interface.h"
   5
   6static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
   7                                        const char *origin, int no,
   8                                        enum grep_pat_token t,
   9                                        enum grep_header_field field)
  10{
  11        struct grep_pat *p = xcalloc(1, sizeof(*p));
  12        p->pattern = pat;
  13        p->patternlen = patlen;
  14        p->origin = origin;
  15        p->no = no;
  16        p->token = t;
  17        p->field = field;
  18        return p;
  19}
  20
  21static void do_append_grep_pat(struct grep_pat ***tail, struct grep_pat *p)
  22{
  23        **tail = p;
  24        *tail = &p->next;
  25        p->next = NULL;
  26}
  27
  28void append_header_grep_pattern(struct grep_opt *opt,
  29                                enum grep_header_field field, const char *pat)
  30{
  31        struct grep_pat *p = create_grep_pat(pat, strlen(pat), "header", 0,
  32                                             GREP_PATTERN_HEAD, field);
  33        do_append_grep_pat(&opt->header_tail, p);
  34}
  35
  36void append_grep_pattern(struct grep_opt *opt, const char *pat,
  37                         const char *origin, int no, enum grep_pat_token t)
  38{
  39        append_grep_pat(opt, pat, strlen(pat), origin, no, t);
  40}
  41
  42void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
  43                     const char *origin, int no, enum grep_pat_token t)
  44{
  45        struct grep_pat *p = create_grep_pat(pat, patlen, origin, no, t, 0);
  46        do_append_grep_pat(&opt->pattern_tail, p);
  47}
  48
  49struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
  50{
  51        struct grep_pat *pat;
  52        struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
  53        *ret = *opt;
  54
  55        ret->pattern_list = NULL;
  56        ret->pattern_tail = &ret->pattern_list;
  57
  58        for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
  59        {
  60                if(pat->token == GREP_PATTERN_HEAD)
  61                        append_header_grep_pattern(ret, pat->field,
  62                                                   pat->pattern);
  63                else
  64                        append_grep_pat(ret, pat->pattern, pat->patternlen,
  65                                        pat->origin, pat->no, pat->token);
  66        }
  67
  68        return ret;
  69}
  70
  71static NORETURN void compile_regexp_failed(const struct grep_pat *p,
  72                const char *error)
  73{
  74        char where[1024];
  75
  76        if (p->no)
  77                sprintf(where, "In '%s' at %d, ", p->origin, p->no);
  78        else if (p->origin)
  79                sprintf(where, "%s, ", p->origin);
  80        else
  81                where[0] = 0;
  82
  83        die("%s'%s': %s", where, p->pattern, error);
  84}
  85
  86#ifdef USE_LIBPCRE
  87static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
  88{
  89        const char *error;
  90        int erroffset;
  91        int options = 0;
  92
  93        if (opt->ignore_case)
  94                options |= PCRE_CASELESS;
  95
  96        p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
  97                        NULL);
  98        if (!p->pcre_regexp)
  99                compile_regexp_failed(p, error);
 100
 101        p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
 102        if (!p->pcre_extra_info && error)
 103                die("%s", error);
 104}
 105
 106static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 107                regmatch_t *match, int eflags)
 108{
 109        int ovector[30], ret, flags = 0;
 110
 111        if (eflags & REG_NOTBOL)
 112                flags |= PCRE_NOTBOL;
 113
 114        ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
 115                        0, flags, ovector, ARRAY_SIZE(ovector));
 116        if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
 117                die("pcre_exec failed with error code %d", ret);
 118        if (ret > 0) {
 119                ret = 0;
 120                match->rm_so = ovector[0];
 121                match->rm_eo = ovector[1];
 122        }
 123
 124        return ret;
 125}
 126
 127static void free_pcre_regexp(struct grep_pat *p)
 128{
 129        pcre_free(p->pcre_regexp);
 130        pcre_free(p->pcre_extra_info);
 131}
 132#else /* !USE_LIBPCRE */
 133static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 134{
 135        die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 136}
 137
 138static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 139                regmatch_t *match, int eflags)
 140{
 141        return 1;
 142}
 143
 144static void free_pcre_regexp(struct grep_pat *p)
 145{
 146}
 147#endif /* !USE_LIBPCRE */
 148
 149static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 150{
 151        int err;
 152
 153        p->word_regexp = opt->word_regexp;
 154        p->ignore_case = opt->ignore_case;
 155        p->fixed = opt->fixed;
 156
 157        if (p->fixed)
 158                return;
 159
 160        if (opt->pcre) {
 161                compile_pcre_regexp(p, opt);
 162                return;
 163        }
 164
 165        err = regcomp(&p->regexp, p->pattern, opt->regflags);
 166        if (err) {
 167                char errbuf[1024];
 168                regerror(err, &p->regexp, errbuf, 1024);
 169                regfree(&p->regexp);
 170                compile_regexp_failed(p, errbuf);
 171        }
 172}
 173
 174static struct grep_expr *compile_pattern_or(struct grep_pat **);
 175static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 176{
 177        struct grep_pat *p;
 178        struct grep_expr *x;
 179
 180        p = *list;
 181        if (!p)
 182                return NULL;
 183        switch (p->token) {
 184        case GREP_PATTERN: /* atom */
 185        case GREP_PATTERN_HEAD:
 186        case GREP_PATTERN_BODY:
 187                x = xcalloc(1, sizeof (struct grep_expr));
 188                x->node = GREP_NODE_ATOM;
 189                x->u.atom = p;
 190                *list = p->next;
 191                return x;
 192        case GREP_OPEN_PAREN:
 193                *list = p->next;
 194                x = compile_pattern_or(list);
 195                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 196                        die("unmatched parenthesis");
 197                *list = (*list)->next;
 198                return x;
 199        default:
 200                return NULL;
 201        }
 202}
 203
 204static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 205{
 206        struct grep_pat *p;
 207        struct grep_expr *x;
 208
 209        p = *list;
 210        if (!p)
 211                return NULL;
 212        switch (p->token) {
 213        case GREP_NOT:
 214                if (!p->next)
 215                        die("--not not followed by pattern expression");
 216                *list = p->next;
 217                x = xcalloc(1, sizeof (struct grep_expr));
 218                x->node = GREP_NODE_NOT;
 219                x->u.unary = compile_pattern_not(list);
 220                if (!x->u.unary)
 221                        die("--not followed by non pattern expression");
 222                return x;
 223        default:
 224                return compile_pattern_atom(list);
 225        }
 226}
 227
 228static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 229{
 230        struct grep_pat *p;
 231        struct grep_expr *x, *y, *z;
 232
 233        x = compile_pattern_not(list);
 234        p = *list;
 235        if (p && p->token == GREP_AND) {
 236                if (!p->next)
 237                        die("--and not followed by pattern expression");
 238                *list = p->next;
 239                y = compile_pattern_and(list);
 240                if (!y)
 241                        die("--and not followed by pattern expression");
 242                z = xcalloc(1, sizeof (struct grep_expr));
 243                z->node = GREP_NODE_AND;
 244                z->u.binary.left = x;
 245                z->u.binary.right = y;
 246                return z;
 247        }
 248        return x;
 249}
 250
 251static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 252{
 253        struct grep_pat *p;
 254        struct grep_expr *x, *y, *z;
 255
 256        x = compile_pattern_and(list);
 257        p = *list;
 258        if (x && p && p->token != GREP_CLOSE_PAREN) {
 259                y = compile_pattern_or(list);
 260                if (!y)
 261                        die("not a pattern expression %s", p->pattern);
 262                z = xcalloc(1, sizeof (struct grep_expr));
 263                z->node = GREP_NODE_OR;
 264                z->u.binary.left = x;
 265                z->u.binary.right = y;
 266                return z;
 267        }
 268        return x;
 269}
 270
 271static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 272{
 273        return compile_pattern_or(list);
 274}
 275
 276static struct grep_expr *grep_true_expr(void)
 277{
 278        struct grep_expr *z = xcalloc(1, sizeof(*z));
 279        z->node = GREP_NODE_TRUE;
 280        return z;
 281}
 282
 283static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 284{
 285        struct grep_expr *z = xcalloc(1, sizeof(*z));
 286        z->node = GREP_NODE_OR;
 287        z->u.binary.left = left;
 288        z->u.binary.right = right;
 289        return z;
 290}
 291
 292static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 293{
 294        struct grep_pat *p;
 295        struct grep_expr *header_expr;
 296        struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 297        enum grep_header_field fld;
 298
 299        if (!opt->header_list)
 300                return NULL;
 301        p = opt->header_list;
 302        for (p = opt->header_list; p; p = p->next) {
 303                if (p->token != GREP_PATTERN_HEAD)
 304                        die("bug: a non-header pattern in grep header list.");
 305                if (p->field < 0 || GREP_HEADER_FIELD_MAX <= p->field)
 306                        die("bug: unknown header field %d", p->field);
 307                compile_regexp(p, opt);
 308        }
 309
 310        for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 311                header_group[fld] = NULL;
 312
 313        for (p = opt->header_list; p; p = p->next) {
 314                struct grep_expr *h;
 315                struct grep_pat *pp = p;
 316
 317                h = compile_pattern_atom(&pp);
 318                if (!h || pp != p->next)
 319                        die("bug: malformed header expr");
 320                if (!header_group[p->field]) {
 321                        header_group[p->field] = h;
 322                        continue;
 323                }
 324                header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 325        }
 326
 327        header_expr = NULL;
 328
 329        for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 330                if (!header_group[fld])
 331                        continue;
 332                if (!header_expr)
 333                        header_expr = grep_true_expr();
 334                header_expr = grep_or_expr(header_group[fld], header_expr);
 335        }
 336        return header_expr;
 337}
 338
 339void compile_grep_patterns(struct grep_opt *opt)
 340{
 341        struct grep_pat *p;
 342        struct grep_expr *header_expr = prep_header_patterns(opt);
 343
 344        for (p = opt->pattern_list; p; p = p->next) {
 345                switch (p->token) {
 346                case GREP_PATTERN: /* atom */
 347                case GREP_PATTERN_HEAD:
 348                case GREP_PATTERN_BODY:
 349                        compile_regexp(p, opt);
 350                        break;
 351                default:
 352                        opt->extended = 1;
 353                        break;
 354                }
 355        }
 356
 357        if (opt->all_match || header_expr)
 358                opt->extended = 1;
 359        else if (!opt->extended)
 360                return;
 361
 362        p = opt->pattern_list;
 363        if (p)
 364                opt->pattern_expression = compile_pattern_expr(&p);
 365        if (p)
 366                die("incomplete pattern expression: %s", p->pattern);
 367
 368        if (!header_expr)
 369                return;
 370
 371        if (!opt->pattern_expression)
 372                opt->pattern_expression = header_expr;
 373        else
 374                opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 375                                                       header_expr);
 376        opt->all_match = 1;
 377}
 378
 379static void free_pattern_expr(struct grep_expr *x)
 380{
 381        switch (x->node) {
 382        case GREP_NODE_TRUE:
 383        case GREP_NODE_ATOM:
 384                break;
 385        case GREP_NODE_NOT:
 386                free_pattern_expr(x->u.unary);
 387                break;
 388        case GREP_NODE_AND:
 389        case GREP_NODE_OR:
 390                free_pattern_expr(x->u.binary.left);
 391                free_pattern_expr(x->u.binary.right);
 392                break;
 393        }
 394        free(x);
 395}
 396
 397void free_grep_patterns(struct grep_opt *opt)
 398{
 399        struct grep_pat *p, *n;
 400
 401        for (p = opt->pattern_list; p; p = n) {
 402                n = p->next;
 403                switch (p->token) {
 404                case GREP_PATTERN: /* atom */
 405                case GREP_PATTERN_HEAD:
 406                case GREP_PATTERN_BODY:
 407                        if (p->pcre_regexp)
 408                                free_pcre_regexp(p);
 409                        else
 410                                regfree(&p->regexp);
 411                        break;
 412                default:
 413                        break;
 414                }
 415                free(p);
 416        }
 417
 418        if (!opt->extended)
 419                return;
 420        free_pattern_expr(opt->pattern_expression);
 421}
 422
 423static char *end_of_line(char *cp, unsigned long *left)
 424{
 425        unsigned long l = *left;
 426        while (l && *cp != '\n') {
 427                l--;
 428                cp++;
 429        }
 430        *left = l;
 431        return cp;
 432}
 433
 434static int word_char(char ch)
 435{
 436        return isalnum(ch) || ch == '_';
 437}
 438
 439static void output_color(struct grep_opt *opt, const void *data, size_t size,
 440                         const char *color)
 441{
 442        if (opt->color && color && color[0]) {
 443                opt->output(opt, color, strlen(color));
 444                opt->output(opt, data, size);
 445                opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 446        } else
 447                opt->output(opt, data, size);
 448}
 449
 450static void output_sep(struct grep_opt *opt, char sign)
 451{
 452        if (opt->null_following_name)
 453                opt->output(opt, "\0", 1);
 454        else
 455                output_color(opt, &sign, 1, opt->color_sep);
 456}
 457
 458static void show_name(struct grep_opt *opt, const char *name)
 459{
 460        output_color(opt, name, strlen(name), opt->color_filename);
 461        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 462}
 463
 464static int fixmatch(struct grep_pat *p, char *line, char *eol,
 465                    regmatch_t *match)
 466{
 467        char *hit;
 468
 469        if (p->ignore_case) {
 470                char *s = line;
 471                do {
 472                        hit = strcasestr(s, p->pattern);
 473                        if (hit)
 474                                break;
 475                        s += strlen(s) + 1;
 476                } while (s < eol);
 477        } else
 478                hit = memmem(line, eol - line, p->pattern, p->patternlen);
 479
 480        if (!hit) {
 481                match->rm_so = match->rm_eo = -1;
 482                return REG_NOMATCH;
 483        }
 484        else {
 485                match->rm_so = hit - line;
 486                match->rm_eo = match->rm_so + p->patternlen;
 487                return 0;
 488        }
 489}
 490
 491static int regmatch(const regex_t *preg, char *line, char *eol,
 492                    regmatch_t *match, int eflags)
 493{
 494#ifdef REG_STARTEND
 495        match->rm_so = 0;
 496        match->rm_eo = eol - line;
 497        eflags |= REG_STARTEND;
 498#endif
 499        return regexec(preg, line, 1, match, eflags);
 500}
 501
 502static int patmatch(struct grep_pat *p, char *line, char *eol,
 503                    regmatch_t *match, int eflags)
 504{
 505        int hit;
 506
 507        if (p->fixed)
 508                hit = !fixmatch(p, line, eol, match);
 509        else if (p->pcre_regexp)
 510                hit = !pcrematch(p, line, eol, match, eflags);
 511        else
 512                hit = !regmatch(&p->regexp, line, eol, match, eflags);
 513
 514        return hit;
 515}
 516
 517static int strip_timestamp(char *bol, char **eol_p)
 518{
 519        char *eol = *eol_p;
 520        int ch;
 521
 522        while (bol < --eol) {
 523                if (*eol != '>')
 524                        continue;
 525                *eol_p = ++eol;
 526                ch = *eol;
 527                *eol = '\0';
 528                return ch;
 529        }
 530        return 0;
 531}
 532
 533static struct {
 534        const char *field;
 535        size_t len;
 536} header_field[] = {
 537        { "author ", 7 },
 538        { "committer ", 10 },
 539};
 540
 541static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 542                             enum grep_context ctx,
 543                             regmatch_t *pmatch, int eflags)
 544{
 545        int hit = 0;
 546        int saved_ch = 0;
 547        const char *start = bol;
 548
 549        if ((p->token != GREP_PATTERN) &&
 550            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 551                return 0;
 552
 553        if (p->token == GREP_PATTERN_HEAD) {
 554                const char *field;
 555                size_t len;
 556                assert(p->field < ARRAY_SIZE(header_field));
 557                field = header_field[p->field].field;
 558                len = header_field[p->field].len;
 559                if (strncmp(bol, field, len))
 560                        return 0;
 561                bol += len;
 562                saved_ch = strip_timestamp(bol, &eol);
 563        }
 564
 565 again:
 566        hit = patmatch(p, bol, eol, pmatch, eflags);
 567
 568        if (hit && p->word_regexp) {
 569                if ((pmatch[0].rm_so < 0) ||
 570                    (eol - bol) < pmatch[0].rm_so ||
 571                    (pmatch[0].rm_eo < 0) ||
 572                    (eol - bol) < pmatch[0].rm_eo)
 573                        die("regexp returned nonsense");
 574
 575                /* Match beginning must be either beginning of the
 576                 * line, or at word boundary (i.e. the last char must
 577                 * not be a word char).  Similarly, match end must be
 578                 * either end of the line, or at word boundary
 579                 * (i.e. the next char must not be a word char).
 580                 */
 581                if ( ((pmatch[0].rm_so == 0) ||
 582                      !word_char(bol[pmatch[0].rm_so-1])) &&
 583                     ((pmatch[0].rm_eo == (eol-bol)) ||
 584                      !word_char(bol[pmatch[0].rm_eo])) )
 585                        ;
 586                else
 587                        hit = 0;
 588
 589                /* Words consist of at least one character. */
 590                if (pmatch->rm_so == pmatch->rm_eo)
 591                        hit = 0;
 592
 593                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 594                        /* There could be more than one match on the
 595                         * line, and the first match might not be
 596                         * strict word match.  But later ones could be!
 597                         * Forward to the next possible start, i.e. the
 598                         * next position following a non-word char.
 599                         */
 600                        bol = pmatch[0].rm_so + bol + 1;
 601                        while (word_char(bol[-1]) && bol < eol)
 602                                bol++;
 603                        eflags |= REG_NOTBOL;
 604                        if (bol < eol)
 605                                goto again;
 606                }
 607        }
 608        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 609                *eol = saved_ch;
 610        if (hit) {
 611                pmatch[0].rm_so += bol - start;
 612                pmatch[0].rm_eo += bol - start;
 613        }
 614        return hit;
 615}
 616
 617static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 618                           enum grep_context ctx, int collect_hits)
 619{
 620        int h = 0;
 621        regmatch_t match;
 622
 623        if (!x)
 624                die("Not a valid grep expression");
 625        switch (x->node) {
 626        case GREP_NODE_TRUE:
 627                h = 1;
 628                break;
 629        case GREP_NODE_ATOM:
 630                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 631                break;
 632        case GREP_NODE_NOT:
 633                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 634                break;
 635        case GREP_NODE_AND:
 636                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 637                        return 0;
 638                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 639                break;
 640        case GREP_NODE_OR:
 641                if (!collect_hits)
 642                        return (match_expr_eval(x->u.binary.left,
 643                                                bol, eol, ctx, 0) ||
 644                                match_expr_eval(x->u.binary.right,
 645                                                bol, eol, ctx, 0));
 646                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 647                x->u.binary.left->hit |= h;
 648                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 649                break;
 650        default:
 651                die("Unexpected node type (internal error) %d", x->node);
 652        }
 653        if (collect_hits)
 654                x->hit |= h;
 655        return h;
 656}
 657
 658static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 659                      enum grep_context ctx, int collect_hits)
 660{
 661        struct grep_expr *x = opt->pattern_expression;
 662        return match_expr_eval(x, bol, eol, ctx, collect_hits);
 663}
 664
 665static int match_line(struct grep_opt *opt, char *bol, char *eol,
 666                      enum grep_context ctx, int collect_hits)
 667{
 668        struct grep_pat *p;
 669        regmatch_t match;
 670
 671        if (opt->extended)
 672                return match_expr(opt, bol, eol, ctx, collect_hits);
 673
 674        /* we do not call with collect_hits without being extended */
 675        for (p = opt->pattern_list; p; p = p->next) {
 676                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 677                        return 1;
 678        }
 679        return 0;
 680}
 681
 682static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 683                              enum grep_context ctx,
 684                              regmatch_t *pmatch, int eflags)
 685{
 686        regmatch_t match;
 687
 688        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 689                return 0;
 690        if (match.rm_so < 0 || match.rm_eo < 0)
 691                return 0;
 692        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 693                if (match.rm_so > pmatch->rm_so)
 694                        return 1;
 695                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 696                        return 1;
 697        }
 698        pmatch->rm_so = match.rm_so;
 699        pmatch->rm_eo = match.rm_eo;
 700        return 1;
 701}
 702
 703static int next_match(struct grep_opt *opt, char *bol, char *eol,
 704                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 705{
 706        struct grep_pat *p;
 707        int hit = 0;
 708
 709        pmatch->rm_so = pmatch->rm_eo = -1;
 710        if (bol < eol) {
 711                for (p = opt->pattern_list; p; p = p->next) {
 712                        switch (p->token) {
 713                        case GREP_PATTERN: /* atom */
 714                        case GREP_PATTERN_HEAD:
 715                        case GREP_PATTERN_BODY:
 716                                hit |= match_next_pattern(p, bol, eol, ctx,
 717                                                          pmatch, eflags);
 718                                break;
 719                        default:
 720                                break;
 721                        }
 722                }
 723        }
 724        return hit;
 725}
 726
 727static void show_line(struct grep_opt *opt, char *bol, char *eol,
 728                      const char *name, unsigned lno, char sign)
 729{
 730        int rest = eol - bol;
 731        char *line_color = NULL;
 732
 733        if (opt->pre_context || opt->post_context) {
 734                if (opt->last_shown == 0) {
 735                        if (opt->show_hunk_mark) {
 736                                output_color(opt, "--", 2, opt->color_sep);
 737                                opt->output(opt, "\n", 1);
 738                        }
 739                } else if (lno > opt->last_shown + 1) {
 740                        output_color(opt, "--", 2, opt->color_sep);
 741                        opt->output(opt, "\n", 1);
 742                }
 743        }
 744        opt->last_shown = lno;
 745
 746        if (opt->pathname) {
 747                output_color(opt, name, strlen(name), opt->color_filename);
 748                output_sep(opt, sign);
 749        }
 750        if (opt->linenum) {
 751                char buf[32];
 752                snprintf(buf, sizeof(buf), "%d", lno);
 753                output_color(opt, buf, strlen(buf), opt->color_lineno);
 754                output_sep(opt, sign);
 755        }
 756        if (opt->color) {
 757                regmatch_t match;
 758                enum grep_context ctx = GREP_CONTEXT_BODY;
 759                int ch = *eol;
 760                int eflags = 0;
 761
 762                if (sign == ':')
 763                        line_color = opt->color_selected;
 764                else if (sign == '-')
 765                        line_color = opt->color_context;
 766                else if (sign == '=')
 767                        line_color = opt->color_function;
 768                *eol = '\0';
 769                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 770                        if (match.rm_so == match.rm_eo)
 771                                break;
 772
 773                        output_color(opt, bol, match.rm_so, line_color);
 774                        output_color(opt, bol + match.rm_so,
 775                                     match.rm_eo - match.rm_so,
 776                                     opt->color_match);
 777                        bol += match.rm_eo;
 778                        rest -= match.rm_eo;
 779                        eflags = REG_NOTBOL;
 780                }
 781                *eol = ch;
 782        }
 783        output_color(opt, bol, rest, line_color);
 784        opt->output(opt, "\n", 1);
 785}
 786
 787static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 788{
 789        xdemitconf_t *xecfg = opt->priv;
 790        if (xecfg && xecfg->find_func) {
 791                char buf[1];
 792                return xecfg->find_func(bol, eol - bol, buf, 1,
 793                                        xecfg->find_func_priv) >= 0;
 794        }
 795
 796        if (bol == eol)
 797                return 0;
 798        if (isalpha(*bol) || *bol == '_' || *bol == '$')
 799                return 1;
 800        return 0;
 801}
 802
 803static void show_funcname_line(struct grep_opt *opt, const char *name,
 804                               char *buf, char *bol, unsigned lno)
 805{
 806        while (bol > buf) {
 807                char *eol = --bol;
 808
 809                while (bol > buf && bol[-1] != '\n')
 810                        bol--;
 811                lno--;
 812
 813                if (lno <= opt->last_shown)
 814                        break;
 815
 816                if (match_funcname(opt, bol, eol)) {
 817                        show_line(opt, bol, eol, name, lno, '=');
 818                        break;
 819                }
 820        }
 821}
 822
 823static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 824                             char *bol, unsigned lno)
 825{
 826        unsigned cur = lno, from = 1, funcname_lno = 0;
 827        int funcname_needed = opt->funcname;
 828
 829        if (opt->pre_context < lno)
 830                from = lno - opt->pre_context;
 831        if (from <= opt->last_shown)
 832                from = opt->last_shown + 1;
 833
 834        /* Rewind. */
 835        while (bol > buf && cur > from) {
 836                char *eol = --bol;
 837
 838                while (bol > buf && bol[-1] != '\n')
 839                        bol--;
 840                cur--;
 841                if (funcname_needed && match_funcname(opt, bol, eol)) {
 842                        funcname_lno = cur;
 843                        funcname_needed = 0;
 844                }
 845        }
 846
 847        /* We need to look even further back to find a function signature. */
 848        if (opt->funcname && funcname_needed)
 849                show_funcname_line(opt, name, buf, bol, cur);
 850
 851        /* Back forward. */
 852        while (cur < lno) {
 853                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 854
 855                while (*eol != '\n')
 856                        eol++;
 857                show_line(opt, bol, eol, name, cur, sign);
 858                bol = eol + 1;
 859                cur++;
 860        }
 861}
 862
 863static int should_lookahead(struct grep_opt *opt)
 864{
 865        struct grep_pat *p;
 866
 867        if (opt->extended)
 868                return 0; /* punt for too complex stuff */
 869        if (opt->invert)
 870                return 0;
 871        for (p = opt->pattern_list; p; p = p->next) {
 872                if (p->token != GREP_PATTERN)
 873                        return 0; /* punt for "header only" and stuff */
 874        }
 875        return 1;
 876}
 877
 878static int look_ahead(struct grep_opt *opt,
 879                      unsigned long *left_p,
 880                      unsigned *lno_p,
 881                      char **bol_p)
 882{
 883        unsigned lno = *lno_p;
 884        char *bol = *bol_p;
 885        struct grep_pat *p;
 886        char *sp, *last_bol;
 887        regoff_t earliest = -1;
 888
 889        for (p = opt->pattern_list; p; p = p->next) {
 890                int hit;
 891                regmatch_t m;
 892
 893                hit = patmatch(p, bol, bol + *left_p, &m, 0);
 894                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 895                        continue;
 896                if (earliest < 0 || m.rm_so < earliest)
 897                        earliest = m.rm_so;
 898        }
 899
 900        if (earliest < 0) {
 901                *bol_p = bol + *left_p;
 902                *left_p = 0;
 903                return 1;
 904        }
 905        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 906                ; /* find the beginning of the line */
 907        last_bol = sp;
 908
 909        for (sp = bol; sp < last_bol; sp++) {
 910                if (*sp == '\n')
 911                        lno++;
 912        }
 913        *left_p -= last_bol - bol;
 914        *bol_p = last_bol;
 915        *lno_p = lno;
 916        return 0;
 917}
 918
 919int grep_threads_ok(const struct grep_opt *opt)
 920{
 921        /* If this condition is true, then we may use the attribute
 922         * machinery in grep_buffer_1. The attribute code is not
 923         * thread safe, so we disable the use of threads.
 924         */
 925        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 926            !opt->name_only)
 927                return 0;
 928
 929        return 1;
 930}
 931
 932static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 933{
 934        fwrite(buf, size, 1, stdout);
 935}
 936
 937static int grep_buffer_1(struct grep_opt *opt, const char *name,
 938                         char *buf, unsigned long size, int collect_hits)
 939{
 940        char *bol = buf;
 941        unsigned long left = size;
 942        unsigned lno = 1;
 943        unsigned last_hit = 0;
 944        int binary_match_only = 0;
 945        unsigned count = 0;
 946        int try_lookahead = 0;
 947        enum grep_context ctx = GREP_CONTEXT_HEAD;
 948        xdemitconf_t xecfg;
 949
 950        if (!opt->output)
 951                opt->output = std_output;
 952
 953        if (opt->last_shown && (opt->pre_context || opt->post_context) &&
 954            opt->output == std_output)
 955                opt->show_hunk_mark = 1;
 956        opt->last_shown = 0;
 957
 958        switch (opt->binary) {
 959        case GREP_BINARY_DEFAULT:
 960                if (buffer_is_binary(buf, size))
 961                        binary_match_only = 1;
 962                break;
 963        case GREP_BINARY_NOMATCH:
 964                if (buffer_is_binary(buf, size))
 965                        return 0; /* Assume unmatch */
 966                break;
 967        case GREP_BINARY_TEXT:
 968                break;
 969        default:
 970                die("bug: unknown binary handling mode");
 971        }
 972
 973        memset(&xecfg, 0, sizeof(xecfg));
 974        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 975            !opt->name_only && !binary_match_only && !collect_hits) {
 976                struct userdiff_driver *drv = userdiff_find_by_path(name);
 977                if (drv && drv->funcname.pattern) {
 978                        const struct userdiff_funcname *pe = &drv->funcname;
 979                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
 980                        opt->priv = &xecfg;
 981                }
 982        }
 983        try_lookahead = should_lookahead(opt);
 984
 985        while (left) {
 986                char *eol, ch;
 987                int hit;
 988
 989                /*
 990                 * look_ahead() skips quickly to the line that possibly
 991                 * has the next hit; don't call it if we need to do
 992                 * something more than just skipping the current line
 993                 * in response to an unmatch for the current line.  E.g.
 994                 * inside a post-context window, we will show the current
 995                 * line as a context around the previous hit when it
 996                 * doesn't hit.
 997                 */
 998                if (try_lookahead
 999                    && !(last_hit
1000                         && lno <= last_hit + opt->post_context)
1001                    && look_ahead(opt, &left, &lno, &bol))
1002                        break;
1003                eol = end_of_line(bol, &left);
1004                ch = *eol;
1005                *eol = 0;
1006
1007                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1008                        ctx = GREP_CONTEXT_BODY;
1009
1010                hit = match_line(opt, bol, eol, ctx, collect_hits);
1011                *eol = ch;
1012
1013                if (collect_hits)
1014                        goto next_line;
1015
1016                /* "grep -v -e foo -e bla" should list lines
1017                 * that do not have either, so inversion should
1018                 * be done outside.
1019                 */
1020                if (opt->invert)
1021                        hit = !hit;
1022                if (opt->unmatch_name_only) {
1023                        if (hit)
1024                                return 0;
1025                        goto next_line;
1026                }
1027                if (hit) {
1028                        count++;
1029                        if (opt->status_only)
1030                                return 1;
1031                        if (opt->name_only) {
1032                                show_name(opt, name);
1033                                return 1;
1034                        }
1035                        if (opt->count)
1036                                goto next_line;
1037                        if (binary_match_only) {
1038                                opt->output(opt, "Binary file ", 12);
1039                                output_color(opt, name, strlen(name),
1040                                             opt->color_filename);
1041                                opt->output(opt, " matches\n", 9);
1042                                return 1;
1043                        }
1044                        /* Hit at this line.  If we haven't shown the
1045                         * pre-context lines, we would need to show them.
1046                         */
1047                        if (opt->pre_context)
1048                                show_pre_context(opt, name, buf, bol, lno);
1049                        else if (opt->funcname)
1050                                show_funcname_line(opt, name, buf, bol, lno);
1051                        show_line(opt, bol, eol, name, lno, ':');
1052                        last_hit = lno;
1053                }
1054                else if (last_hit &&
1055                         lno <= last_hit + opt->post_context) {
1056                        /* If the last hit is within the post context,
1057                         * we need to show this line.
1058                         */
1059                        show_line(opt, bol, eol, name, lno, '-');
1060                }
1061
1062        next_line:
1063                bol = eol + 1;
1064                if (!left)
1065                        break;
1066                left--;
1067                lno++;
1068        }
1069
1070        if (collect_hits)
1071                return 0;
1072
1073        if (opt->status_only)
1074                return 0;
1075        if (opt->unmatch_name_only) {
1076                /* We did not see any hit, so we want to show this */
1077                show_name(opt, name);
1078                return 1;
1079        }
1080
1081        xdiff_clear_find_func(&xecfg);
1082        opt->priv = NULL;
1083
1084        /* NEEDSWORK:
1085         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1086         * which feels mostly useless but sometimes useful.  Maybe
1087         * make it another option?  For now suppress them.
1088         */
1089        if (opt->count && count) {
1090                char buf[32];
1091                output_color(opt, name, strlen(name), opt->color_filename);
1092                output_sep(opt, ':');
1093                snprintf(buf, sizeof(buf), "%u\n", count);
1094                opt->output(opt, buf, strlen(buf));
1095                return 1;
1096        }
1097        return !!last_hit;
1098}
1099
1100static void clr_hit_marker(struct grep_expr *x)
1101{
1102        /* All-hit markers are meaningful only at the very top level
1103         * OR node.
1104         */
1105        while (1) {
1106                x->hit = 0;
1107                if (x->node != GREP_NODE_OR)
1108                        return;
1109                x->u.binary.left->hit = 0;
1110                x = x->u.binary.right;
1111        }
1112}
1113
1114static int chk_hit_marker(struct grep_expr *x)
1115{
1116        /* Top level nodes have hit markers.  See if they all are hits */
1117        while (1) {
1118                if (x->node != GREP_NODE_OR)
1119                        return x->hit;
1120                if (!x->u.binary.left->hit)
1121                        return 0;
1122                x = x->u.binary.right;
1123        }
1124}
1125
1126int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
1127{
1128        /*
1129         * we do not have to do the two-pass grep when we do not check
1130         * buffer-wide "all-match".
1131         */
1132        if (!opt->all_match)
1133                return grep_buffer_1(opt, name, buf, size, 0);
1134
1135        /* Otherwise the toplevel "or" terms hit a bit differently.
1136         * We first clear hit markers from them.
1137         */
1138        clr_hit_marker(opt->pattern_expression);
1139        grep_buffer_1(opt, name, buf, size, 1);
1140
1141        if (!chk_hit_marker(opt->pattern_expression))
1142                return 0;
1143
1144        return grep_buffer_1(opt, name, buf, size, 0);
1145}