Andrew's git / gitweb.git / grep.c
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grep.con commit Merge branch 'wp/doc-filter-direction' into maint (0737975)
   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->header_tail = p;
  15        opt->header_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        struct grep_expr *header_expr = NULL;
 188
 189        if (opt->header_list) {
 190                p = opt->header_list;
 191                header_expr = compile_pattern_expr(&p);
 192                if (p)
 193                        die("incomplete pattern expression: %s", p->pattern);
 194                for (p = opt->header_list; p; p = p->next) {
 195                        switch (p->token) {
 196                        case GREP_PATTERN: /* atom */
 197                        case GREP_PATTERN_HEAD:
 198                        case GREP_PATTERN_BODY:
 199                                compile_regexp(p, opt);
 200                                break;
 201                        default:
 202                                opt->extended = 1;
 203                                break;
 204                        }
 205                }
 206        }
 207
 208        for (p = opt->pattern_list; p; p = p->next) {
 209                switch (p->token) {
 210                case GREP_PATTERN: /* atom */
 211                case GREP_PATTERN_HEAD:
 212                case GREP_PATTERN_BODY:
 213                        compile_regexp(p, opt);
 214                        break;
 215                default:
 216                        opt->extended = 1;
 217                        break;
 218                }
 219        }
 220
 221        if (opt->all_match || header_expr)
 222                opt->extended = 1;
 223        else if (!opt->extended)
 224                return;
 225
 226        /* Then bundle them up in an expression.
 227         * A classic recursive descent parser would do.
 228         */
 229        p = opt->pattern_list;
 230        if (p)
 231                opt->pattern_expression = compile_pattern_expr(&p);
 232        if (p)
 233                die("incomplete pattern expression: %s", p->pattern);
 234
 235        if (!header_expr)
 236                return;
 237
 238        if (opt->pattern_expression) {
 239                struct grep_expr *z;
 240                z = xcalloc(1, sizeof(*z));
 241                z->node = GREP_NODE_OR;
 242                z->u.binary.left = opt->pattern_expression;
 243                z->u.binary.right = header_expr;
 244                opt->pattern_expression = z;
 245        } else {
 246                opt->pattern_expression = header_expr;
 247        }
 248        opt->all_match = 1;
 249}
 250
 251static void free_pattern_expr(struct grep_expr *x)
 252{
 253        switch (x->node) {
 254        case GREP_NODE_ATOM:
 255                break;
 256        case GREP_NODE_NOT:
 257                free_pattern_expr(x->u.unary);
 258                break;
 259        case GREP_NODE_AND:
 260        case GREP_NODE_OR:
 261                free_pattern_expr(x->u.binary.left);
 262                free_pattern_expr(x->u.binary.right);
 263                break;
 264        }
 265        free(x);
 266}
 267
 268void free_grep_patterns(struct grep_opt *opt)
 269{
 270        struct grep_pat *p, *n;
 271
 272        for (p = opt->pattern_list; p; p = n) {
 273                n = p->next;
 274                switch (p->token) {
 275                case GREP_PATTERN: /* atom */
 276                case GREP_PATTERN_HEAD:
 277                case GREP_PATTERN_BODY:
 278                        regfree(&p->regexp);
 279                        break;
 280                default:
 281                        break;
 282                }
 283                free(p);
 284        }
 285
 286        if (!opt->extended)
 287                return;
 288        free_pattern_expr(opt->pattern_expression);
 289}
 290
 291static char *end_of_line(char *cp, unsigned long *left)
 292{
 293        unsigned long l = *left;
 294        while (l && *cp != '\n') {
 295                l--;
 296                cp++;
 297        }
 298        *left = l;
 299        return cp;
 300}
 301
 302static int word_char(char ch)
 303{
 304        return isalnum(ch) || ch == '_';
 305}
 306
 307static void show_name(struct grep_opt *opt, const char *name)
 308{
 309        opt->output(opt, name, strlen(name));
 310        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 311}
 312
 313
 314static int fixmatch(const char *pattern, char *line, int ignore_case, regmatch_t *match)
 315{
 316        char *hit;
 317        if (ignore_case)
 318                hit = strcasestr(line, pattern);
 319        else
 320                hit = strstr(line, pattern);
 321
 322        if (!hit) {
 323                match->rm_so = match->rm_eo = -1;
 324                return REG_NOMATCH;
 325        }
 326        else {
 327                match->rm_so = hit - line;
 328                match->rm_eo = match->rm_so + strlen(pattern);
 329                return 0;
 330        }
 331}
 332
 333static int strip_timestamp(char *bol, char **eol_p)
 334{
 335        char *eol = *eol_p;
 336        int ch;
 337
 338        while (bol < --eol) {
 339                if (*eol != '>')
 340                        continue;
 341                *eol_p = ++eol;
 342                ch = *eol;
 343                *eol = '\0';
 344                return ch;
 345        }
 346        return 0;
 347}
 348
 349static struct {
 350        const char *field;
 351        size_t len;
 352} header_field[] = {
 353        { "author ", 7 },
 354        { "committer ", 10 },
 355};
 356
 357static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 358                             enum grep_context ctx,
 359                             regmatch_t *pmatch, int eflags)
 360{
 361        int hit = 0;
 362        int saved_ch = 0;
 363        const char *start = bol;
 364
 365        if ((p->token != GREP_PATTERN) &&
 366            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 367                return 0;
 368
 369        if (p->token == GREP_PATTERN_HEAD) {
 370                const char *field;
 371                size_t len;
 372                assert(p->field < ARRAY_SIZE(header_field));
 373                field = header_field[p->field].field;
 374                len = header_field[p->field].len;
 375                if (strncmp(bol, field, len))
 376                        return 0;
 377                bol += len;
 378                saved_ch = strip_timestamp(bol, &eol);
 379        }
 380
 381 again:
 382        if (p->fixed)
 383                hit = !fixmatch(p->pattern, bol, p->ignore_case, pmatch);
 384        else
 385                hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 386
 387        if (hit && p->word_regexp) {
 388                if ((pmatch[0].rm_so < 0) ||
 389                    (eol - bol) < pmatch[0].rm_so ||
 390                    (pmatch[0].rm_eo < 0) ||
 391                    (eol - bol) < pmatch[0].rm_eo)
 392                        die("regexp returned nonsense");
 393
 394                /* Match beginning must be either beginning of the
 395                 * line, or at word boundary (i.e. the last char must
 396                 * not be a word char).  Similarly, match end must be
 397                 * either end of the line, or at word boundary
 398                 * (i.e. the next char must not be a word char).
 399                 */
 400                if ( ((pmatch[0].rm_so == 0) ||
 401                      !word_char(bol[pmatch[0].rm_so-1])) &&
 402                     ((pmatch[0].rm_eo == (eol-bol)) ||
 403                      !word_char(bol[pmatch[0].rm_eo])) )
 404                        ;
 405                else
 406                        hit = 0;
 407
 408                /* Words consist of at least one character. */
 409                if (pmatch->rm_so == pmatch->rm_eo)
 410                        hit = 0;
 411
 412                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 413                        /* There could be more than one match on the
 414                         * line, and the first match might not be
 415                         * strict word match.  But later ones could be!
 416                         * Forward to the next possible start, i.e. the
 417                         * next position following a non-word char.
 418                         */
 419                        bol = pmatch[0].rm_so + bol + 1;
 420                        while (word_char(bol[-1]) && bol < eol)
 421                                bol++;
 422                        eflags |= REG_NOTBOL;
 423                        if (bol < eol)
 424                                goto again;
 425                }
 426        }
 427        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 428                *eol = saved_ch;
 429        if (hit) {
 430                pmatch[0].rm_so += bol - start;
 431                pmatch[0].rm_eo += bol - start;
 432        }
 433        return hit;
 434}
 435
 436static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 437                           enum grep_context ctx, int collect_hits)
 438{
 439        int h = 0;
 440        regmatch_t match;
 441
 442        if (!x)
 443                die("Not a valid grep expression");
 444        switch (x->node) {
 445        case GREP_NODE_ATOM:
 446                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 447                break;
 448        case GREP_NODE_NOT:
 449                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 450                break;
 451        case GREP_NODE_AND:
 452                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 453                        return 0;
 454                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 455                break;
 456        case GREP_NODE_OR:
 457                if (!collect_hits)
 458                        return (match_expr_eval(x->u.binary.left,
 459                                                bol, eol, ctx, 0) ||
 460                                match_expr_eval(x->u.binary.right,
 461                                                bol, eol, ctx, 0));
 462                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 463                x->u.binary.left->hit |= h;
 464                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 465                break;
 466        default:
 467                die("Unexpected node type (internal error) %d", x->node);
 468        }
 469        if (collect_hits)
 470                x->hit |= h;
 471        return h;
 472}
 473
 474static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 475                      enum grep_context ctx, int collect_hits)
 476{
 477        struct grep_expr *x = opt->pattern_expression;
 478        return match_expr_eval(x, bol, eol, ctx, collect_hits);
 479}
 480
 481static int match_line(struct grep_opt *opt, char *bol, char *eol,
 482                      enum grep_context ctx, int collect_hits)
 483{
 484        struct grep_pat *p;
 485        regmatch_t match;
 486
 487        if (opt->extended)
 488                return match_expr(opt, bol, eol, ctx, collect_hits);
 489
 490        /* we do not call with collect_hits without being extended */
 491        for (p = opt->pattern_list; p; p = p->next) {
 492                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 493                        return 1;
 494        }
 495        return 0;
 496}
 497
 498static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 499                              enum grep_context ctx,
 500                              regmatch_t *pmatch, int eflags)
 501{
 502        regmatch_t match;
 503
 504        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 505                return 0;
 506        if (match.rm_so < 0 || match.rm_eo < 0)
 507                return 0;
 508        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 509                if (match.rm_so > pmatch->rm_so)
 510                        return 1;
 511                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 512                        return 1;
 513        }
 514        pmatch->rm_so = match.rm_so;
 515        pmatch->rm_eo = match.rm_eo;
 516        return 1;
 517}
 518
 519static int next_match(struct grep_opt *opt, char *bol, char *eol,
 520                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 521{
 522        struct grep_pat *p;
 523        int hit = 0;
 524
 525        pmatch->rm_so = pmatch->rm_eo = -1;
 526        if (bol < eol) {
 527                for (p = opt->pattern_list; p; p = p->next) {
 528                        switch (p->token) {
 529                        case GREP_PATTERN: /* atom */
 530                        case GREP_PATTERN_HEAD:
 531                        case GREP_PATTERN_BODY:
 532                                hit |= match_next_pattern(p, bol, eol, ctx,
 533                                                          pmatch, eflags);
 534                                break;
 535                        default:
 536                                break;
 537                        }
 538                }
 539        }
 540        return hit;
 541}
 542
 543static void show_line(struct grep_opt *opt, char *bol, char *eol,
 544                      const char *name, unsigned lno, char sign)
 545{
 546        int rest = eol - bol;
 547        char sign_str[1];
 548
 549        sign_str[0] = sign;
 550        if (opt->pre_context || opt->post_context) {
 551                if (opt->last_shown == 0) {
 552                        if (opt->show_hunk_mark)
 553                                opt->output(opt, "--\n", 3);
 554                        else
 555                                opt->show_hunk_mark = 1;
 556                } else if (lno > opt->last_shown + 1)
 557                        opt->output(opt, "--\n", 3);
 558        }
 559        opt->last_shown = lno;
 560
 561        if (opt->null_following_name)
 562                sign_str[0] = '\0';
 563        if (opt->pathname) {
 564                opt->output(opt, name, strlen(name));
 565                opt->output(opt, sign_str, 1);
 566        }
 567        if (opt->linenum) {
 568                char buf[32];
 569                snprintf(buf, sizeof(buf), "%d", lno);
 570                opt->output(opt, buf, strlen(buf));
 571                opt->output(opt, sign_str, 1);
 572        }
 573        if (opt->color) {
 574                regmatch_t match;
 575                enum grep_context ctx = GREP_CONTEXT_BODY;
 576                int ch = *eol;
 577                int eflags = 0;
 578
 579                *eol = '\0';
 580                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 581                        if (match.rm_so == match.rm_eo)
 582                                break;
 583
 584                        opt->output(opt, bol, match.rm_so);
 585                        opt->output(opt, opt->color_match,
 586                                    strlen(opt->color_match));
 587                        opt->output(opt, bol + match.rm_so,
 588                                    (int)(match.rm_eo - match.rm_so));
 589                        opt->output(opt, GIT_COLOR_RESET,
 590                                    strlen(GIT_COLOR_RESET));
 591                        bol += match.rm_eo;
 592                        rest -= match.rm_eo;
 593                        eflags = REG_NOTBOL;
 594                }
 595                *eol = ch;
 596        }
 597        opt->output(opt, bol, rest);
 598        opt->output(opt, "\n", 1);
 599}
 600
 601static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 602{
 603        xdemitconf_t *xecfg = opt->priv;
 604        if (xecfg && xecfg->find_func) {
 605                char buf[1];
 606                return xecfg->find_func(bol, eol - bol, buf, 1,
 607                                        xecfg->find_func_priv) >= 0;
 608        }
 609
 610        if (bol == eol)
 611                return 0;
 612        if (isalpha(*bol) || *bol == '_' || *bol == '$')
 613                return 1;
 614        return 0;
 615}
 616
 617static void show_funcname_line(struct grep_opt *opt, const char *name,
 618                               char *buf, char *bol, unsigned lno)
 619{
 620        while (bol > buf) {
 621                char *eol = --bol;
 622
 623                while (bol > buf && bol[-1] != '\n')
 624                        bol--;
 625                lno--;
 626
 627                if (lno <= opt->last_shown)
 628                        break;
 629
 630                if (match_funcname(opt, bol, eol)) {
 631                        show_line(opt, bol, eol, name, lno, '=');
 632                        break;
 633                }
 634        }
 635}
 636
 637static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 638                             char *bol, unsigned lno)
 639{
 640        unsigned cur = lno, from = 1, funcname_lno = 0;
 641        int funcname_needed = opt->funcname;
 642
 643        if (opt->pre_context < lno)
 644                from = lno - opt->pre_context;
 645        if (from <= opt->last_shown)
 646                from = opt->last_shown + 1;
 647
 648        /* Rewind. */
 649        while (bol > buf && cur > from) {
 650                char *eol = --bol;
 651
 652                while (bol > buf && bol[-1] != '\n')
 653                        bol--;
 654                cur--;
 655                if (funcname_needed && match_funcname(opt, bol, eol)) {
 656                        funcname_lno = cur;
 657                        funcname_needed = 0;
 658                }
 659        }
 660
 661        /* We need to look even further back to find a function signature. */
 662        if (opt->funcname && funcname_needed)
 663                show_funcname_line(opt, name, buf, bol, cur);
 664
 665        /* Back forward. */
 666        while (cur < lno) {
 667                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 668
 669                while (*eol != '\n')
 670                        eol++;
 671                show_line(opt, bol, eol, name, cur, sign);
 672                bol = eol + 1;
 673                cur++;
 674        }
 675}
 676
 677static int should_lookahead(struct grep_opt *opt)
 678{
 679        struct grep_pat *p;
 680
 681        if (opt->extended)
 682                return 0; /* punt for too complex stuff */
 683        if (opt->invert)
 684                return 0;
 685        for (p = opt->pattern_list; p; p = p->next) {
 686                if (p->token != GREP_PATTERN)
 687                        return 0; /* punt for "header only" and stuff */
 688        }
 689        return 1;
 690}
 691
 692static int look_ahead(struct grep_opt *opt,
 693                      unsigned long *left_p,
 694                      unsigned *lno_p,
 695                      char **bol_p)
 696{
 697        unsigned lno = *lno_p;
 698        char *bol = *bol_p;
 699        struct grep_pat *p;
 700        char *sp, *last_bol;
 701        regoff_t earliest = -1;
 702
 703        for (p = opt->pattern_list; p; p = p->next) {
 704                int hit;
 705                regmatch_t m;
 706
 707                if (p->fixed)
 708                        hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
 709                else {
 710#ifdef REG_STARTEND
 711                        m.rm_so = 0;
 712                        m.rm_eo = *left_p;
 713                        hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND);
 714#else
 715                        hit = !regexec(&p->regexp, bol, 1, &m, 0);
 716#endif
 717                }
 718                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 719                        continue;
 720                if (earliest < 0 || m.rm_so < earliest)
 721                        earliest = m.rm_so;
 722        }
 723
 724        if (earliest < 0) {
 725                *bol_p = bol + *left_p;
 726                *left_p = 0;
 727                return 1;
 728        }
 729        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 730                ; /* find the beginning of the line */
 731        last_bol = sp;
 732
 733        for (sp = bol; sp < last_bol; sp++) {
 734                if (*sp == '\n')
 735                        lno++;
 736        }
 737        *left_p -= last_bol - bol;
 738        *bol_p = last_bol;
 739        *lno_p = lno;
 740        return 0;
 741}
 742
 743int grep_threads_ok(const struct grep_opt *opt)
 744{
 745        /* If this condition is true, then we may use the attribute
 746         * machinery in grep_buffer_1. The attribute code is not
 747         * thread safe, so we disable the use of threads.
 748         */
 749        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 750            !opt->name_only)
 751                return 0;
 752
 753        /* If we are showing hunk marks, we should not do it for the
 754         * first match. The synchronization problem we get for this
 755         * constraint is not yet solved, so we disable threading in
 756         * this case.
 757         */
 758        if (opt->pre_context || opt->post_context)
 759                return 0;
 760
 761        return 1;
 762}
 763
 764static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 765{
 766        fwrite(buf, size, 1, stdout);
 767}
 768
 769static int grep_buffer_1(struct grep_opt *opt, const char *name,
 770                         char *buf, unsigned long size, int collect_hits)
 771{
 772        char *bol = buf;
 773        unsigned long left = size;
 774        unsigned lno = 1;
 775        unsigned last_hit = 0;
 776        int binary_match_only = 0;
 777        unsigned count = 0;
 778        int try_lookahead = 0;
 779        enum grep_context ctx = GREP_CONTEXT_HEAD;
 780        xdemitconf_t xecfg;
 781
 782        opt->last_shown = 0;
 783
 784        if (!opt->output)
 785                opt->output = std_output;
 786
 787        if (buffer_is_binary(buf, size)) {
 788                switch (opt->binary) {
 789                case GREP_BINARY_DEFAULT:
 790                        binary_match_only = 1;
 791                        break;
 792                case GREP_BINARY_NOMATCH:
 793                        return 0; /* Assume unmatch */
 794                        break;
 795                default:
 796                        break;
 797                }
 798        }
 799
 800        memset(&xecfg, 0, sizeof(xecfg));
 801        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 802            !opt->name_only && !binary_match_only && !collect_hits) {
 803                struct userdiff_driver *drv = userdiff_find_by_path(name);
 804                if (drv && drv->funcname.pattern) {
 805                        const struct userdiff_funcname *pe = &drv->funcname;
 806                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
 807                        opt->priv = &xecfg;
 808                }
 809        }
 810        try_lookahead = should_lookahead(opt);
 811
 812        while (left) {
 813                char *eol, ch;
 814                int hit;
 815
 816                /*
 817                 * look_ahead() skips quicly to the line that possibly
 818                 * has the next hit; don't call it if we need to do
 819                 * something more than just skipping the current line
 820                 * in response to an unmatch for the current line.  E.g.
 821                 * inside a post-context window, we will show the current
 822                 * line as a context around the previous hit when it
 823                 * doesn't hit.
 824                 */
 825                if (try_lookahead
 826                    && !(last_hit
 827                         && lno <= last_hit + opt->post_context)
 828                    && look_ahead(opt, &left, &lno, &bol))
 829                        break;
 830                eol = end_of_line(bol, &left);
 831                ch = *eol;
 832                *eol = 0;
 833
 834                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 835                        ctx = GREP_CONTEXT_BODY;
 836
 837                hit = match_line(opt, bol, eol, ctx, collect_hits);
 838                *eol = ch;
 839
 840                if (collect_hits)
 841                        goto next_line;
 842
 843                /* "grep -v -e foo -e bla" should list lines
 844                 * that do not have either, so inversion should
 845                 * be done outside.
 846                 */
 847                if (opt->invert)
 848                        hit = !hit;
 849                if (opt->unmatch_name_only) {
 850                        if (hit)
 851                                return 0;
 852                        goto next_line;
 853                }
 854                if (hit) {
 855                        count++;
 856                        if (opt->status_only)
 857                                return 1;
 858                        if (binary_match_only) {
 859                                opt->output(opt, "Binary file ", 12);
 860                                opt->output(opt, name, strlen(name));
 861                                opt->output(opt, " matches\n", 9);
 862                                return 1;
 863                        }
 864                        if (opt->name_only) {
 865                                show_name(opt, name);
 866                                return 1;
 867                        }
 868                        /* Hit at this line.  If we haven't shown the
 869                         * pre-context lines, we would need to show them.
 870                         * When asked to do "count", this still show
 871                         * the context which is nonsense, but the user
 872                         * deserves to get that ;-).
 873                         */
 874                        if (opt->pre_context)
 875                                show_pre_context(opt, name, buf, bol, lno);
 876                        else if (opt->funcname)
 877                                show_funcname_line(opt, name, buf, bol, lno);
 878                        if (!opt->count)
 879                                show_line(opt, bol, eol, name, lno, ':');
 880                        last_hit = lno;
 881                }
 882                else if (last_hit &&
 883                         lno <= last_hit + opt->post_context) {
 884                        /* If the last hit is within the post context,
 885                         * we need to show this line.
 886                         */
 887                        show_line(opt, bol, eol, name, lno, '-');
 888                }
 889
 890        next_line:
 891                bol = eol + 1;
 892                if (!left)
 893                        break;
 894                left--;
 895                lno++;
 896        }
 897
 898        if (collect_hits)
 899                return 0;
 900
 901        if (opt->status_only)
 902                return 0;
 903        if (opt->unmatch_name_only) {
 904                /* We did not see any hit, so we want to show this */
 905                show_name(opt, name);
 906                return 1;
 907        }
 908
 909        xdiff_clear_find_func(&xecfg);
 910        opt->priv = NULL;
 911
 912        /* NEEDSWORK:
 913         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 914         * which feels mostly useless but sometimes useful.  Maybe
 915         * make it another option?  For now suppress them.
 916         */
 917        if (opt->count && count) {
 918                char buf[32];
 919                opt->output(opt, name, strlen(name));
 920                snprintf(buf, sizeof(buf), "%c%u\n",
 921                         opt->null_following_name ? '\0' : ':', count);
 922                opt->output(opt, buf, strlen(buf));
 923        }
 924        return !!last_hit;
 925}
 926
 927static void clr_hit_marker(struct grep_expr *x)
 928{
 929        /* All-hit markers are meaningful only at the very top level
 930         * OR node.
 931         */
 932        while (1) {
 933                x->hit = 0;
 934                if (x->node != GREP_NODE_OR)
 935                        return;
 936                x->u.binary.left->hit = 0;
 937                x = x->u.binary.right;
 938        }
 939}
 940
 941static int chk_hit_marker(struct grep_expr *x)
 942{
 943        /* Top level nodes have hit markers.  See if they all are hits */
 944        while (1) {
 945                if (x->node != GREP_NODE_OR)
 946                        return x->hit;
 947                if (!x->u.binary.left->hit)
 948                        return 0;
 949                x = x->u.binary.right;
 950        }
 951}
 952
 953int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 954{
 955        /*
 956         * we do not have to do the two-pass grep when we do not check
 957         * buffer-wide "all-match".
 958         */
 959        if (!opt->all_match)
 960                return grep_buffer_1(opt, name, buf, size, 0);
 961
 962        /* Otherwise the toplevel "or" terms hit a bit differently.
 963         * We first clear hit markers from them.
 964         */
 965        clr_hit_marker(opt->pattern_expression);
 966        grep_buffer_1(opt, name, buf, size, 1);
 967
 968        if (!chk_hit_marker(opt->pattern_expression))
 969                return 0;
 970
 971        return grep_buffer_1(opt, name, buf, size, 0);
 972}