Andrew's git / gitweb.git / grep.c
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grep.con commit index-pack: smarter memory usage when appending objects (7734d7f)
   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->origin = "header";
  11        p->no = 0;
  12        p->token = GREP_PATTERN_HEAD;
  13        p->field = field;
  14        *opt->pattern_tail = p;
  15        opt->pattern_tail = &p->next;
  16        p->next = NULL;
  17}
  18
  19void append_grep_pattern(struct grep_opt *opt, const char *pat,
  20                         const char *origin, int no, enum grep_pat_token t)
  21{
  22        struct grep_pat *p = xcalloc(1, sizeof(*p));
  23        p->pattern = pat;
  24        p->origin = origin;
  25        p->no = no;
  26        p->token = t;
  27        *opt->pattern_tail = p;
  28        opt->pattern_tail = &p->next;
  29        p->next = NULL;
  30}
  31
  32struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
  33{
  34        struct grep_pat *pat;
  35        struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
  36        *ret = *opt;
  37
  38        ret->pattern_list = NULL;
  39        ret->pattern_tail = &ret->pattern_list;
  40
  41        for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
  42        {
  43                if(pat->token == GREP_PATTERN_HEAD)
  44                        append_header_grep_pattern(ret, pat->field,
  45                                                   pat->pattern);
  46                else
  47                        append_grep_pattern(ret, pat->pattern, pat->origin,
  48                                            pat->no, pat->token);
  49        }
  50
  51        return ret;
  52}
  53
  54static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  55{
  56        int err;
  57
  58        p->word_regexp = opt->word_regexp;
  59        p->ignore_case = opt->ignore_case;
  60        p->fixed = opt->fixed;
  61
  62        if (p->fixed)
  63                return;
  64
  65        err = regcomp(&p->regexp, p->pattern, opt->regflags);
  66        if (err) {
  67                char errbuf[1024];
  68                char where[1024];
  69                if (p->no)
  70                        sprintf(where, "In '%s' at %d, ",
  71                                p->origin, p->no);
  72                else if (p->origin)
  73                        sprintf(where, "%s, ", p->origin);
  74                else
  75                        where[0] = 0;
  76                regerror(err, &p->regexp, errbuf, 1024);
  77                regfree(&p->regexp);
  78                die("%s'%s': %s", where, p->pattern, errbuf);
  79        }
  80}
  81
  82static struct grep_expr *compile_pattern_or(struct grep_pat **);
  83static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  84{
  85        struct grep_pat *p;
  86        struct grep_expr *x;
  87
  88        p = *list;
  89        if (!p)
  90                return NULL;
  91        switch (p->token) {
  92        case GREP_PATTERN: /* atom */
  93        case GREP_PATTERN_HEAD:
  94        case GREP_PATTERN_BODY:
  95                x = xcalloc(1, sizeof (struct grep_expr));
  96                x->node = GREP_NODE_ATOM;
  97                x->u.atom = p;
  98                *list = p->next;
  99                return x;
 100        case GREP_OPEN_PAREN:
 101                *list = p->next;
 102                x = compile_pattern_or(list);
 103                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 104                        die("unmatched parenthesis");
 105                *list = (*list)->next;
 106                return x;
 107        default:
 108                return NULL;
 109        }
 110}
 111
 112static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 113{
 114        struct grep_pat *p;
 115        struct grep_expr *x;
 116
 117        p = *list;
 118        if (!p)
 119                return NULL;
 120        switch (p->token) {
 121        case GREP_NOT:
 122                if (!p->next)
 123                        die("--not not followed by pattern expression");
 124                *list = p->next;
 125                x = xcalloc(1, sizeof (struct grep_expr));
 126                x->node = GREP_NODE_NOT;
 127                x->u.unary = compile_pattern_not(list);
 128                if (!x->u.unary)
 129                        die("--not followed by non pattern expression");
 130                return x;
 131        default:
 132                return compile_pattern_atom(list);
 133        }
 134}
 135
 136static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 137{
 138        struct grep_pat *p;
 139        struct grep_expr *x, *y, *z;
 140
 141        x = compile_pattern_not(list);
 142        p = *list;
 143        if (p && p->token == GREP_AND) {
 144                if (!p->next)
 145                        die("--and not followed by pattern expression");
 146                *list = p->next;
 147                y = compile_pattern_and(list);
 148                if (!y)
 149                        die("--and not followed by pattern expression");
 150                z = xcalloc(1, sizeof (struct grep_expr));
 151                z->node = GREP_NODE_AND;
 152                z->u.binary.left = x;
 153                z->u.binary.right = y;
 154                return z;
 155        }
 156        return x;
 157}
 158
 159static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 160{
 161        struct grep_pat *p;
 162        struct grep_expr *x, *y, *z;
 163
 164        x = compile_pattern_and(list);
 165        p = *list;
 166        if (x && p && p->token != GREP_CLOSE_PAREN) {
 167                y = compile_pattern_or(list);
 168                if (!y)
 169                        die("not a pattern expression %s", p->pattern);
 170                z = xcalloc(1, sizeof (struct grep_expr));
 171                z->node = GREP_NODE_OR;
 172                z->u.binary.left = x;
 173                z->u.binary.right = y;
 174                return z;
 175        }
 176        return x;
 177}
 178
 179static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 180{
 181        return compile_pattern_or(list);
 182}
 183
 184void compile_grep_patterns(struct grep_opt *opt)
 185{
 186        struct grep_pat *p;
 187
 188        if (opt->all_match)
 189                opt->extended = 1;
 190
 191        for (p = opt->pattern_list; p; p = p->next) {
 192                switch (p->token) {
 193                case GREP_PATTERN: /* atom */
 194                case GREP_PATTERN_HEAD:
 195                case GREP_PATTERN_BODY:
 196                        compile_regexp(p, opt);
 197                        break;
 198                default:
 199                        opt->extended = 1;
 200                        break;
 201                }
 202        }
 203
 204        if (!opt->extended)
 205                return;
 206
 207        /* Then bundle them up in an expression.
 208         * A classic recursive descent parser would do.
 209         */
 210        p = opt->pattern_list;
 211        if (p)
 212                opt->pattern_expression = compile_pattern_expr(&p);
 213        if (p)
 214                die("incomplete pattern expression: %s", p->pattern);
 215}
 216
 217static void free_pattern_expr(struct grep_expr *x)
 218{
 219        switch (x->node) {
 220        case GREP_NODE_ATOM:
 221                break;
 222        case GREP_NODE_NOT:
 223                free_pattern_expr(x->u.unary);
 224                break;
 225        case GREP_NODE_AND:
 226        case GREP_NODE_OR:
 227                free_pattern_expr(x->u.binary.left);
 228                free_pattern_expr(x->u.binary.right);
 229                break;
 230        }
 231        free(x);
 232}
 233
 234void free_grep_patterns(struct grep_opt *opt)
 235{
 236        struct grep_pat *p, *n;
 237
 238        for (p = opt->pattern_list; p; p = n) {
 239                n = p->next;
 240                switch (p->token) {
 241                case GREP_PATTERN: /* atom */
 242                case GREP_PATTERN_HEAD:
 243                case GREP_PATTERN_BODY:
 244                        regfree(&p->regexp);
 245                        break;
 246                default:
 247                        break;
 248                }
 249                free(p);
 250        }
 251
 252        if (!opt->extended)
 253                return;
 254        free_pattern_expr(opt->pattern_expression);
 255}
 256
 257static char *end_of_line(char *cp, unsigned long *left)
 258{
 259        unsigned long l = *left;
 260        while (l && *cp != '\n') {
 261                l--;
 262                cp++;
 263        }
 264        *left = l;
 265        return cp;
 266}
 267
 268static int word_char(char ch)
 269{
 270        return isalnum(ch) || ch == '_';
 271}
 272
 273static void show_name(struct grep_opt *opt, const char *name)
 274{
 275        opt->output(opt, name, strlen(name));
 276        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 277}
 278
 279
 280static int fixmatch(const char *pattern, char *line, int ignore_case, regmatch_t *match)
 281{
 282        char *hit;
 283        if (ignore_case)
 284                hit = strcasestr(line, pattern);
 285        else
 286                hit = strstr(line, pattern);
 287
 288        if (!hit) {
 289                match->rm_so = match->rm_eo = -1;
 290                return REG_NOMATCH;
 291        }
 292        else {
 293                match->rm_so = hit - line;
 294                match->rm_eo = match->rm_so + strlen(pattern);
 295                return 0;
 296        }
 297}
 298
 299static int strip_timestamp(char *bol, char **eol_p)
 300{
 301        char *eol = *eol_p;
 302        int ch;
 303
 304        while (bol < --eol) {
 305                if (*eol != '>')
 306                        continue;
 307                *eol_p = ++eol;
 308                ch = *eol;
 309                *eol = '\0';
 310                return ch;
 311        }
 312        return 0;
 313}
 314
 315static struct {
 316        const char *field;
 317        size_t len;
 318} header_field[] = {
 319        { "author ", 7 },
 320        { "committer ", 10 },
 321};
 322
 323static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 324                             enum grep_context ctx,
 325                             regmatch_t *pmatch, int eflags)
 326{
 327        int hit = 0;
 328        int saved_ch = 0;
 329        const char *start = bol;
 330
 331        if ((p->token != GREP_PATTERN) &&
 332            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 333                return 0;
 334
 335        if (p->token == GREP_PATTERN_HEAD) {
 336                const char *field;
 337                size_t len;
 338                assert(p->field < ARRAY_SIZE(header_field));
 339                field = header_field[p->field].field;
 340                len = header_field[p->field].len;
 341                if (strncmp(bol, field, len))
 342                        return 0;
 343                bol += len;
 344                saved_ch = strip_timestamp(bol, &eol);
 345        }
 346
 347 again:
 348        if (p->fixed)
 349                hit = !fixmatch(p->pattern, bol, p->ignore_case, pmatch);
 350        else
 351                hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 352
 353        if (hit && p->word_regexp) {
 354                if ((pmatch[0].rm_so < 0) ||
 355                    (eol - bol) < pmatch[0].rm_so ||
 356                    (pmatch[0].rm_eo < 0) ||
 357                    (eol - bol) < pmatch[0].rm_eo)
 358                        die("regexp returned nonsense");
 359
 360                /* Match beginning must be either beginning of the
 361                 * line, or at word boundary (i.e. the last char must
 362                 * not be a word char).  Similarly, match end must be
 363                 * either end of the line, or at word boundary
 364                 * (i.e. the next char must not be a word char).
 365                 */
 366                if ( ((pmatch[0].rm_so == 0) ||
 367                      !word_char(bol[pmatch[0].rm_so-1])) &&
 368                     ((pmatch[0].rm_eo == (eol-bol)) ||
 369                      !word_char(bol[pmatch[0].rm_eo])) )
 370                        ;
 371                else
 372                        hit = 0;
 373
 374                /* Words consist of at least one character. */
 375                if (pmatch->rm_so == pmatch->rm_eo)
 376                        hit = 0;
 377
 378                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 379                        /* There could be more than one match on the
 380                         * line, and the first match might not be
 381                         * strict word match.  But later ones could be!
 382                         * Forward to the next possible start, i.e. the
 383                         * next position following a non-word char.
 384                         */
 385                        bol = pmatch[0].rm_so + bol + 1;
 386                        while (word_char(bol[-1]) && bol < eol)
 387                                bol++;
 388                        eflags |= REG_NOTBOL;
 389                        if (bol < eol)
 390                                goto again;
 391                }
 392        }
 393        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 394                *eol = saved_ch;
 395        if (hit) {
 396                pmatch[0].rm_so += bol - start;
 397                pmatch[0].rm_eo += bol - start;
 398        }
 399        return hit;
 400}
 401
 402static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 403                           enum grep_context ctx, int collect_hits)
 404{
 405        int h = 0;
 406        regmatch_t match;
 407
 408        if (!x)
 409                die("Not a valid grep expression");
 410        switch (x->node) {
 411        case GREP_NODE_ATOM:
 412                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 413                break;
 414        case GREP_NODE_NOT:
 415                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 416                break;
 417        case GREP_NODE_AND:
 418                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 419                        return 0;
 420                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 421                break;
 422        case GREP_NODE_OR:
 423                if (!collect_hits)
 424                        return (match_expr_eval(x->u.binary.left,
 425                                                bol, eol, ctx, 0) ||
 426                                match_expr_eval(x->u.binary.right,
 427                                                bol, eol, ctx, 0));
 428                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 429                x->u.binary.left->hit |= h;
 430                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 431                break;
 432        default:
 433                die("Unexpected node type (internal error) %d", x->node);
 434        }
 435        if (collect_hits)
 436                x->hit |= h;
 437        return h;
 438}
 439
 440static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 441                      enum grep_context ctx, int collect_hits)
 442{
 443        struct grep_expr *x = opt->pattern_expression;
 444        return match_expr_eval(x, bol, eol, ctx, collect_hits);
 445}
 446
 447static int match_line(struct grep_opt *opt, char *bol, char *eol,
 448                      enum grep_context ctx, int collect_hits)
 449{
 450        struct grep_pat *p;
 451        regmatch_t match;
 452
 453        if (opt->extended)
 454                return match_expr(opt, bol, eol, ctx, collect_hits);
 455
 456        /* we do not call with collect_hits without being extended */
 457        for (p = opt->pattern_list; p; p = p->next) {
 458                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 459                        return 1;
 460        }
 461        return 0;
 462}
 463
 464static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 465                              enum grep_context ctx,
 466                              regmatch_t *pmatch, int eflags)
 467{
 468        regmatch_t match;
 469
 470        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 471                return 0;
 472        if (match.rm_so < 0 || match.rm_eo < 0)
 473                return 0;
 474        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 475                if (match.rm_so > pmatch->rm_so)
 476                        return 1;
 477                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 478                        return 1;
 479        }
 480        pmatch->rm_so = match.rm_so;
 481        pmatch->rm_eo = match.rm_eo;
 482        return 1;
 483}
 484
 485static int next_match(struct grep_opt *opt, char *bol, char *eol,
 486                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 487{
 488        struct grep_pat *p;
 489        int hit = 0;
 490
 491        pmatch->rm_so = pmatch->rm_eo = -1;
 492        if (bol < eol) {
 493                for (p = opt->pattern_list; p; p = p->next) {
 494                        switch (p->token) {
 495                        case GREP_PATTERN: /* atom */
 496                        case GREP_PATTERN_HEAD:
 497                        case GREP_PATTERN_BODY:
 498                                hit |= match_next_pattern(p, bol, eol, ctx,
 499                                                          pmatch, eflags);
 500                                break;
 501                        default:
 502                                break;
 503                        }
 504                }
 505        }
 506        return hit;
 507}
 508
 509static void show_line(struct grep_opt *opt, char *bol, char *eol,
 510                      const char *name, unsigned lno, char sign)
 511{
 512        int rest = eol - bol;
 513        char sign_str[1];
 514
 515        sign_str[0] = sign;
 516        if (opt->pre_context || opt->post_context) {
 517                if (opt->last_shown == 0) {
 518                        if (opt->show_hunk_mark)
 519                                opt->output(opt, "--\n", 3);
 520                        else
 521                                opt->show_hunk_mark = 1;
 522                } else if (lno > opt->last_shown + 1)
 523                        opt->output(opt, "--\n", 3);
 524        }
 525        opt->last_shown = lno;
 526
 527        if (opt->null_following_name)
 528                sign_str[0] = '\0';
 529        if (opt->pathname) {
 530                opt->output(opt, name, strlen(name));
 531                opt->output(opt, sign_str, 1);
 532        }
 533        if (opt->linenum) {
 534                char buf[32];
 535                snprintf(buf, sizeof(buf), "%d", lno);
 536                opt->output(opt, buf, strlen(buf));
 537                opt->output(opt, sign_str, 1);
 538        }
 539        if (opt->color) {
 540                regmatch_t match;
 541                enum grep_context ctx = GREP_CONTEXT_BODY;
 542                int ch = *eol;
 543                int eflags = 0;
 544
 545                *eol = '\0';
 546                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 547                        if (match.rm_so == match.rm_eo)
 548                                break;
 549
 550                        opt->output(opt, bol, match.rm_so);
 551                        opt->output(opt, opt->color_match,
 552                                    strlen(opt->color_match));
 553                        opt->output(opt, bol + match.rm_so,
 554                                    (int)(match.rm_eo - match.rm_so));
 555                        opt->output(opt, GIT_COLOR_RESET,
 556                                    strlen(GIT_COLOR_RESET));
 557                        bol += match.rm_eo;
 558                        rest -= match.rm_eo;
 559                        eflags = REG_NOTBOL;
 560                }
 561                *eol = ch;
 562        }
 563        opt->output(opt, bol, rest);
 564        opt->output(opt, "\n", 1);
 565}
 566
 567static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 568{
 569        xdemitconf_t *xecfg = opt->priv;
 570        if (xecfg && xecfg->find_func) {
 571                char buf[1];
 572                return xecfg->find_func(bol, eol - bol, buf, 1,
 573                                        xecfg->find_func_priv) >= 0;
 574        }
 575
 576        if (bol == eol)
 577                return 0;
 578        if (isalpha(*bol) || *bol == '_' || *bol == '$')
 579                return 1;
 580        return 0;
 581}
 582
 583static void show_funcname_line(struct grep_opt *opt, const char *name,
 584                               char *buf, char *bol, unsigned lno)
 585{
 586        while (bol > buf) {
 587                char *eol = --bol;
 588
 589                while (bol > buf && bol[-1] != '\n')
 590                        bol--;
 591                lno--;
 592
 593                if (lno <= opt->last_shown)
 594                        break;
 595
 596                if (match_funcname(opt, bol, eol)) {
 597                        show_line(opt, bol, eol, name, lno, '=');
 598                        break;
 599                }
 600        }
 601}
 602
 603static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 604                             char *bol, unsigned lno)
 605{
 606        unsigned cur = lno, from = 1, funcname_lno = 0;
 607        int funcname_needed = opt->funcname;
 608
 609        if (opt->pre_context < lno)
 610                from = lno - opt->pre_context;
 611        if (from <= opt->last_shown)
 612                from = opt->last_shown + 1;
 613
 614        /* Rewind. */
 615        while (bol > buf && cur > from) {
 616                char *eol = --bol;
 617
 618                while (bol > buf && bol[-1] != '\n')
 619                        bol--;
 620                cur--;
 621                if (funcname_needed && match_funcname(opt, bol, eol)) {
 622                        funcname_lno = cur;
 623                        funcname_needed = 0;
 624                }
 625        }
 626
 627        /* We need to look even further back to find a function signature. */
 628        if (opt->funcname && funcname_needed)
 629                show_funcname_line(opt, name, buf, bol, cur);
 630
 631        /* Back forward. */
 632        while (cur < lno) {
 633                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 634
 635                while (*eol != '\n')
 636                        eol++;
 637                show_line(opt, bol, eol, name, cur, sign);
 638                bol = eol + 1;
 639                cur++;
 640        }
 641}
 642
 643static int should_lookahead(struct grep_opt *opt)
 644{
 645        struct grep_pat *p;
 646
 647        if (opt->extended)
 648                return 0; /* punt for too complex stuff */
 649        if (opt->invert)
 650                return 0;
 651        for (p = opt->pattern_list; p; p = p->next) {
 652                if (p->token != GREP_PATTERN)
 653                        return 0; /* punt for "header only" and stuff */
 654        }
 655        return 1;
 656}
 657
 658static int look_ahead(struct grep_opt *opt,
 659                      unsigned long *left_p,
 660                      unsigned *lno_p,
 661                      char **bol_p)
 662{
 663        unsigned lno = *lno_p;
 664        char *bol = *bol_p;
 665        struct grep_pat *p;
 666        char *sp, *last_bol;
 667        regoff_t earliest = -1;
 668
 669        for (p = opt->pattern_list; p; p = p->next) {
 670                int hit;
 671                regmatch_t m;
 672
 673                if (p->fixed)
 674                        hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
 675                else {
 676#ifdef REG_STARTEND
 677                        m.rm_so = 0;
 678                        m.rm_eo = *left_p;
 679                        hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND);
 680#else
 681                        hit = !regexec(&p->regexp, bol, 1, &m, 0);
 682#endif
 683                }
 684                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 685                        continue;
 686                if (earliest < 0 || m.rm_so < earliest)
 687                        earliest = m.rm_so;
 688        }
 689
 690        if (earliest < 0) {
 691                *bol_p = bol + *left_p;
 692                *left_p = 0;
 693                return 1;
 694        }
 695        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 696                ; /* find the beginning of the line */
 697        last_bol = sp;
 698
 699        for (sp = bol; sp < last_bol; sp++) {
 700                if (*sp == '\n')
 701                        lno++;
 702        }
 703        *left_p -= last_bol - bol;
 704        *bol_p = last_bol;
 705        *lno_p = lno;
 706        return 0;
 707}
 708
 709int grep_threads_ok(const struct grep_opt *opt)
 710{
 711        /* If this condition is true, then we may use the attribute
 712         * machinery in grep_buffer_1. The attribute code is not
 713         * thread safe, so we disable the use of threads.
 714         */
 715        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 716            !opt->name_only)
 717                return 0;
 718
 719        /* If we are showing hunk marks, we should not do it for the
 720         * first match. The synchronization problem we get for this
 721         * constraint is not yet solved, so we disable threading in
 722         * this case.
 723         */
 724        if (opt->pre_context || opt->post_context)
 725                return 0;
 726
 727        return 1;
 728}
 729
 730static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 731{
 732        fwrite(buf, size, 1, stdout);
 733}
 734
 735static int grep_buffer_1(struct grep_opt *opt, const char *name,
 736                         char *buf, unsigned long size, int collect_hits)
 737{
 738        char *bol = buf;
 739        unsigned long left = size;
 740        unsigned lno = 1;
 741        unsigned last_hit = 0;
 742        int binary_match_only = 0;
 743        unsigned count = 0;
 744        int try_lookahead = 0;
 745        enum grep_context ctx = GREP_CONTEXT_HEAD;
 746        xdemitconf_t xecfg;
 747
 748        opt->last_shown = 0;
 749
 750        if (!opt->output)
 751                opt->output = std_output;
 752
 753        if (buffer_is_binary(buf, size)) {
 754                switch (opt->binary) {
 755                case GREP_BINARY_DEFAULT:
 756                        binary_match_only = 1;
 757                        break;
 758                case GREP_BINARY_NOMATCH:
 759                        return 0; /* Assume unmatch */
 760                        break;
 761                default:
 762                        break;
 763                }
 764        }
 765
 766        memset(&xecfg, 0, sizeof(xecfg));
 767        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 768            !opt->name_only && !binary_match_only && !collect_hits) {
 769                struct userdiff_driver *drv = userdiff_find_by_path(name);
 770                if (drv && drv->funcname.pattern) {
 771                        const struct userdiff_funcname *pe = &drv->funcname;
 772                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
 773                        opt->priv = &xecfg;
 774                }
 775        }
 776        try_lookahead = should_lookahead(opt);
 777
 778        while (left) {
 779                char *eol, ch;
 780                int hit;
 781
 782                /*
 783                 * look_ahead() skips quicly to the line that possibly
 784                 * has the next hit; don't call it if we need to do
 785                 * something more than just skipping the current line
 786                 * in response to an unmatch for the current line.  E.g.
 787                 * inside a post-context window, we will show the current
 788                 * line as a context around the previous hit when it
 789                 * doesn't hit.
 790                 */
 791                if (try_lookahead
 792                    && !(last_hit
 793                         && lno <= last_hit + opt->post_context)
 794                    && look_ahead(opt, &left, &lno, &bol))
 795                        break;
 796                eol = end_of_line(bol, &left);
 797                ch = *eol;
 798                *eol = 0;
 799
 800                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 801                        ctx = GREP_CONTEXT_BODY;
 802
 803                hit = match_line(opt, bol, eol, ctx, collect_hits);
 804                *eol = ch;
 805
 806                if (collect_hits)
 807                        goto next_line;
 808
 809                /* "grep -v -e foo -e bla" should list lines
 810                 * that do not have either, so inversion should
 811                 * be done outside.
 812                 */
 813                if (opt->invert)
 814                        hit = !hit;
 815                if (opt->unmatch_name_only) {
 816                        if (hit)
 817                                return 0;
 818                        goto next_line;
 819                }
 820                if (hit) {
 821                        count++;
 822                        if (opt->status_only)
 823                                return 1;
 824                        if (binary_match_only) {
 825                                opt->output(opt, "Binary file ", 12);
 826                                opt->output(opt, name, strlen(name));
 827                                opt->output(opt, " matches\n", 9);
 828                                return 1;
 829                        }
 830                        if (opt->name_only) {
 831                                show_name(opt, name);
 832                                return 1;
 833                        }
 834                        /* Hit at this line.  If we haven't shown the
 835                         * pre-context lines, we would need to show them.
 836                         * When asked to do "count", this still show
 837                         * the context which is nonsense, but the user
 838                         * deserves to get that ;-).
 839                         */
 840                        if (opt->pre_context)
 841                                show_pre_context(opt, name, buf, bol, lno);
 842                        else if (opt->funcname)
 843                                show_funcname_line(opt, name, buf, bol, lno);
 844                        if (!opt->count)
 845                                show_line(opt, bol, eol, name, lno, ':');
 846                        last_hit = lno;
 847                }
 848                else if (last_hit &&
 849                         lno <= last_hit + opt->post_context) {
 850                        /* If the last hit is within the post context,
 851                         * we need to show this line.
 852                         */
 853                        show_line(opt, bol, eol, name, lno, '-');
 854                }
 855
 856        next_line:
 857                bol = eol + 1;
 858                if (!left)
 859                        break;
 860                left--;
 861                lno++;
 862        }
 863
 864        if (collect_hits)
 865                return 0;
 866
 867        if (opt->status_only)
 868                return 0;
 869        if (opt->unmatch_name_only) {
 870                /* We did not see any hit, so we want to show this */
 871                show_name(opt, name);
 872                return 1;
 873        }
 874
 875        xdiff_clear_find_func(&xecfg);
 876        opt->priv = NULL;
 877
 878        /* NEEDSWORK:
 879         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 880         * which feels mostly useless but sometimes useful.  Maybe
 881         * make it another option?  For now suppress them.
 882         */
 883        if (opt->count && count) {
 884                char buf[32];
 885                opt->output(opt, name, strlen(name));
 886                snprintf(buf, sizeof(buf), "%c%u\n",
 887                         opt->null_following_name ? '\0' : ':', count);
 888                opt->output(opt, buf, strlen(buf));
 889        }
 890        return !!last_hit;
 891}
 892
 893static void clr_hit_marker(struct grep_expr *x)
 894{
 895        /* All-hit markers are meaningful only at the very top level
 896         * OR node.
 897         */
 898        while (1) {
 899                x->hit = 0;
 900                if (x->node != GREP_NODE_OR)
 901                        return;
 902                x->u.binary.left->hit = 0;
 903                x = x->u.binary.right;
 904        }
 905}
 906
 907static int chk_hit_marker(struct grep_expr *x)
 908{
 909        /* Top level nodes have hit markers.  See if they all are hits */
 910        while (1) {
 911                if (x->node != GREP_NODE_OR)
 912                        return x->hit;
 913                if (!x->u.binary.left->hit)
 914                        return 0;
 915                x = x->u.binary.right;
 916        }
 917}
 918
 919int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 920{
 921        /*
 922         * we do not have to do the two-pass grep when we do not check
 923         * buffer-wide "all-match".
 924         */
 925        if (!opt->all_match)
 926                return grep_buffer_1(opt, name, buf, size, 0);
 927
 928        /* Otherwise the toplevel "or" terms hit a bit differently.
 929         * We first clear hit markers from them.
 930         */
 931        clr_hit_marker(opt->pattern_expression);
 932        grep_buffer_1(opt, name, buf, size, 1);
 933
 934        if (!chk_hit_marker(opt->pattern_expression))
 935                return 0;
 936
 937        return grep_buffer_1(opt, name, buf, size, 0);
 938}