42e915d762d82cdb81b5cb5028eee04b707a0aa5
   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 output_color(struct grep_opt *opt, const void *data, size_t size,
 274                         const char *color)
 275{
 276        if (opt->color && color && color[0]) {
 277                opt->output(opt, color, strlen(color));
 278                opt->output(opt, data, size);
 279                opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 280        } else
 281                opt->output(opt, data, size);
 282}
 283
 284static void output_sep(struct grep_opt *opt, char sign)
 285{
 286        if (opt->null_following_name)
 287                opt->output(opt, "\0", 1);
 288        else
 289                output_color(opt, &sign, 1, opt->color_sep);
 290}
 291
 292static void show_name(struct grep_opt *opt, const char *name)
 293{
 294        output_color(opt, name, strlen(name), opt->color_filename);
 295        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 296}
 297
 298
 299static int fixmatch(const char *pattern, char *line, int ignore_case, regmatch_t *match)
 300{
 301        char *hit;
 302        if (ignore_case)
 303                hit = strcasestr(line, pattern);
 304        else
 305                hit = strstr(line, pattern);
 306
 307        if (!hit) {
 308                match->rm_so = match->rm_eo = -1;
 309                return REG_NOMATCH;
 310        }
 311        else {
 312                match->rm_so = hit - line;
 313                match->rm_eo = match->rm_so + strlen(pattern);
 314                return 0;
 315        }
 316}
 317
 318static int strip_timestamp(char *bol, char **eol_p)
 319{
 320        char *eol = *eol_p;
 321        int ch;
 322
 323        while (bol < --eol) {
 324                if (*eol != '>')
 325                        continue;
 326                *eol_p = ++eol;
 327                ch = *eol;
 328                *eol = '\0';
 329                return ch;
 330        }
 331        return 0;
 332}
 333
 334static struct {
 335        const char *field;
 336        size_t len;
 337} header_field[] = {
 338        { "author ", 7 },
 339        { "committer ", 10 },
 340};
 341
 342static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 343                             enum grep_context ctx,
 344                             regmatch_t *pmatch, int eflags)
 345{
 346        int hit = 0;
 347        int saved_ch = 0;
 348        const char *start = bol;
 349
 350        if ((p->token != GREP_PATTERN) &&
 351            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 352                return 0;
 353
 354        if (p->token == GREP_PATTERN_HEAD) {
 355                const char *field;
 356                size_t len;
 357                assert(p->field < ARRAY_SIZE(header_field));
 358                field = header_field[p->field].field;
 359                len = header_field[p->field].len;
 360                if (strncmp(bol, field, len))
 361                        return 0;
 362                bol += len;
 363                saved_ch = strip_timestamp(bol, &eol);
 364        }
 365
 366 again:
 367        if (p->fixed)
 368                hit = !fixmatch(p->pattern, bol, p->ignore_case, pmatch);
 369        else
 370                hit = !regexec(&p->regexp, bol, 1, pmatch, eflags);
 371
 372        if (hit && p->word_regexp) {
 373                if ((pmatch[0].rm_so < 0) ||
 374                    (eol - bol) < pmatch[0].rm_so ||
 375                    (pmatch[0].rm_eo < 0) ||
 376                    (eol - bol) < pmatch[0].rm_eo)
 377                        die("regexp returned nonsense");
 378
 379                /* Match beginning must be either beginning of the
 380                 * line, or at word boundary (i.e. the last char must
 381                 * not be a word char).  Similarly, match end must be
 382                 * either end of the line, or at word boundary
 383                 * (i.e. the next char must not be a word char).
 384                 */
 385                if ( ((pmatch[0].rm_so == 0) ||
 386                      !word_char(bol[pmatch[0].rm_so-1])) &&
 387                     ((pmatch[0].rm_eo == (eol-bol)) ||
 388                      !word_char(bol[pmatch[0].rm_eo])) )
 389                        ;
 390                else
 391                        hit = 0;
 392
 393                /* Words consist of at least one character. */
 394                if (pmatch->rm_so == pmatch->rm_eo)
 395                        hit = 0;
 396
 397                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 398                        /* There could be more than one match on the
 399                         * line, and the first match might not be
 400                         * strict word match.  But later ones could be!
 401                         * Forward to the next possible start, i.e. the
 402                         * next position following a non-word char.
 403                         */
 404                        bol = pmatch[0].rm_so + bol + 1;
 405                        while (word_char(bol[-1]) && bol < eol)
 406                                bol++;
 407                        eflags |= REG_NOTBOL;
 408                        if (bol < eol)
 409                                goto again;
 410                }
 411        }
 412        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 413                *eol = saved_ch;
 414        if (hit) {
 415                pmatch[0].rm_so += bol - start;
 416                pmatch[0].rm_eo += bol - start;
 417        }
 418        return hit;
 419}
 420
 421static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 422                           enum grep_context ctx, int collect_hits)
 423{
 424        int h = 0;
 425        regmatch_t match;
 426
 427        if (!x)
 428                die("Not a valid grep expression");
 429        switch (x->node) {
 430        case GREP_NODE_ATOM:
 431                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 432                break;
 433        case GREP_NODE_NOT:
 434                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 435                break;
 436        case GREP_NODE_AND:
 437                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 438                        return 0;
 439                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 440                break;
 441        case GREP_NODE_OR:
 442                if (!collect_hits)
 443                        return (match_expr_eval(x->u.binary.left,
 444                                                bol, eol, ctx, 0) ||
 445                                match_expr_eval(x->u.binary.right,
 446                                                bol, eol, ctx, 0));
 447                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
 448                x->u.binary.left->hit |= h;
 449                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
 450                break;
 451        default:
 452                die("Unexpected node type (internal error) %d", x->node);
 453        }
 454        if (collect_hits)
 455                x->hit |= h;
 456        return h;
 457}
 458
 459static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 460                      enum grep_context ctx, int collect_hits)
 461{
 462        struct grep_expr *x = opt->pattern_expression;
 463        return match_expr_eval(x, bol, eol, ctx, collect_hits);
 464}
 465
 466static int match_line(struct grep_opt *opt, char *bol, char *eol,
 467                      enum grep_context ctx, int collect_hits)
 468{
 469        struct grep_pat *p;
 470        regmatch_t match;
 471
 472        if (opt->extended)
 473                return match_expr(opt, bol, eol, ctx, collect_hits);
 474
 475        /* we do not call with collect_hits without being extended */
 476        for (p = opt->pattern_list; p; p = p->next) {
 477                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
 478                        return 1;
 479        }
 480        return 0;
 481}
 482
 483static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
 484                              enum grep_context ctx,
 485                              regmatch_t *pmatch, int eflags)
 486{
 487        regmatch_t match;
 488
 489        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
 490                return 0;
 491        if (match.rm_so < 0 || match.rm_eo < 0)
 492                return 0;
 493        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
 494                if (match.rm_so > pmatch->rm_so)
 495                        return 1;
 496                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
 497                        return 1;
 498        }
 499        pmatch->rm_so = match.rm_so;
 500        pmatch->rm_eo = match.rm_eo;
 501        return 1;
 502}
 503
 504static int next_match(struct grep_opt *opt, char *bol, char *eol,
 505                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
 506{
 507        struct grep_pat *p;
 508        int hit = 0;
 509
 510        pmatch->rm_so = pmatch->rm_eo = -1;
 511        if (bol < eol) {
 512                for (p = opt->pattern_list; p; p = p->next) {
 513                        switch (p->token) {
 514                        case GREP_PATTERN: /* atom */
 515                        case GREP_PATTERN_HEAD:
 516                        case GREP_PATTERN_BODY:
 517                                hit |= match_next_pattern(p, bol, eol, ctx,
 518                                                          pmatch, eflags);
 519                                break;
 520                        default:
 521                                break;
 522                        }
 523                }
 524        }
 525        return hit;
 526}
 527
 528static void show_line(struct grep_opt *opt, char *bol, char *eol,
 529                      const char *name, unsigned lno, char sign)
 530{
 531        int rest = eol - bol;
 532
 533        if (opt->pre_context || opt->post_context) {
 534                if (opt->last_shown == 0) {
 535                        if (opt->show_hunk_mark) {
 536                                output_color(opt, "--", 2, opt->color_sep);
 537                                opt->output(opt, "\n", 1);
 538                        } else
 539                                opt->show_hunk_mark = 1;
 540                } else if (lno > opt->last_shown + 1) {
 541                        output_color(opt, "--", 2, opt->color_sep);
 542                        opt->output(opt, "\n", 1);
 543                }
 544        }
 545        opt->last_shown = lno;
 546
 547        if (opt->pathname) {
 548                output_color(opt, name, strlen(name), opt->color_filename);
 549                output_sep(opt, sign);
 550        }
 551        if (opt->linenum) {
 552                char buf[32];
 553                snprintf(buf, sizeof(buf), "%d", lno);
 554                output_color(opt, buf, strlen(buf), opt->color_lineno);
 555                output_sep(opt, sign);
 556        }
 557        if (opt->color) {
 558                regmatch_t match;
 559                enum grep_context ctx = GREP_CONTEXT_BODY;
 560                int ch = *eol;
 561                int eflags = 0;
 562
 563                *eol = '\0';
 564                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
 565                        if (match.rm_so == match.rm_eo)
 566                                break;
 567
 568                        opt->output(opt, bol, match.rm_so);
 569                        output_color(opt, bol + match.rm_so,
 570                                     match.rm_eo - match.rm_so,
 571                                     opt->color_match);
 572                        bol += match.rm_eo;
 573                        rest -= match.rm_eo;
 574                        eflags = REG_NOTBOL;
 575                }
 576                *eol = ch;
 577        }
 578        opt->output(opt, bol, rest);
 579        opt->output(opt, "\n", 1);
 580}
 581
 582static int match_funcname(struct grep_opt *opt, char *bol, char *eol)
 583{
 584        xdemitconf_t *xecfg = opt->priv;
 585        if (xecfg && xecfg->find_func) {
 586                char buf[1];
 587                return xecfg->find_func(bol, eol - bol, buf, 1,
 588                                        xecfg->find_func_priv) >= 0;
 589        }
 590
 591        if (bol == eol)
 592                return 0;
 593        if (isalpha(*bol) || *bol == '_' || *bol == '$')
 594                return 1;
 595        return 0;
 596}
 597
 598static void show_funcname_line(struct grep_opt *opt, const char *name,
 599                               char *buf, char *bol, unsigned lno)
 600{
 601        while (bol > buf) {
 602                char *eol = --bol;
 603
 604                while (bol > buf && bol[-1] != '\n')
 605                        bol--;
 606                lno--;
 607
 608                if (lno <= opt->last_shown)
 609                        break;
 610
 611                if (match_funcname(opt, bol, eol)) {
 612                        show_line(opt, bol, eol, name, lno, '=');
 613                        break;
 614                }
 615        }
 616}
 617
 618static void show_pre_context(struct grep_opt *opt, const char *name, char *buf,
 619                             char *bol, unsigned lno)
 620{
 621        unsigned cur = lno, from = 1, funcname_lno = 0;
 622        int funcname_needed = opt->funcname;
 623
 624        if (opt->pre_context < lno)
 625                from = lno - opt->pre_context;
 626        if (from <= opt->last_shown)
 627                from = opt->last_shown + 1;
 628
 629        /* Rewind. */
 630        while (bol > buf && cur > from) {
 631                char *eol = --bol;
 632
 633                while (bol > buf && bol[-1] != '\n')
 634                        bol--;
 635                cur--;
 636                if (funcname_needed && match_funcname(opt, bol, eol)) {
 637                        funcname_lno = cur;
 638                        funcname_needed = 0;
 639                }
 640        }
 641
 642        /* We need to look even further back to find a function signature. */
 643        if (opt->funcname && funcname_needed)
 644                show_funcname_line(opt, name, buf, bol, cur);
 645
 646        /* Back forward. */
 647        while (cur < lno) {
 648                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
 649
 650                while (*eol != '\n')
 651                        eol++;
 652                show_line(opt, bol, eol, name, cur, sign);
 653                bol = eol + 1;
 654                cur++;
 655        }
 656}
 657
 658static int should_lookahead(struct grep_opt *opt)
 659{
 660        struct grep_pat *p;
 661
 662        if (opt->extended)
 663                return 0; /* punt for too complex stuff */
 664        if (opt->invert)
 665                return 0;
 666        for (p = opt->pattern_list; p; p = p->next) {
 667                if (p->token != GREP_PATTERN)
 668                        return 0; /* punt for "header only" and stuff */
 669        }
 670        return 1;
 671}
 672
 673static int look_ahead(struct grep_opt *opt,
 674                      unsigned long *left_p,
 675                      unsigned *lno_p,
 676                      char **bol_p)
 677{
 678        unsigned lno = *lno_p;
 679        char *bol = *bol_p;
 680        struct grep_pat *p;
 681        char *sp, *last_bol;
 682        regoff_t earliest = -1;
 683
 684        for (p = opt->pattern_list; p; p = p->next) {
 685                int hit;
 686                regmatch_t m;
 687
 688                if (p->fixed)
 689                        hit = !fixmatch(p->pattern, bol, p->ignore_case, &m);
 690                else {
 691#ifdef REG_STARTEND
 692                        m.rm_so = 0;
 693                        m.rm_eo = *left_p;
 694                        hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND);
 695#else
 696                        hit = !regexec(&p->regexp, bol, 1, &m, 0);
 697#endif
 698                }
 699                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
 700                        continue;
 701                if (earliest < 0 || m.rm_so < earliest)
 702                        earliest = m.rm_so;
 703        }
 704
 705        if (earliest < 0) {
 706                *bol_p = bol + *left_p;
 707                *left_p = 0;
 708                return 1;
 709        }
 710        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
 711                ; /* find the beginning of the line */
 712        last_bol = sp;
 713
 714        for (sp = bol; sp < last_bol; sp++) {
 715                if (*sp == '\n')
 716                        lno++;
 717        }
 718        *left_p -= last_bol - bol;
 719        *bol_p = last_bol;
 720        *lno_p = lno;
 721        return 0;
 722}
 723
 724int grep_threads_ok(const struct grep_opt *opt)
 725{
 726        /* If this condition is true, then we may use the attribute
 727         * machinery in grep_buffer_1. The attribute code is not
 728         * thread safe, so we disable the use of threads.
 729         */
 730        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 731            !opt->name_only)
 732                return 0;
 733
 734        /* If we are showing hunk marks, we should not do it for the
 735         * first match. The synchronization problem we get for this
 736         * constraint is not yet solved, so we disable threading in
 737         * this case.
 738         */
 739        if (opt->pre_context || opt->post_context)
 740                return 0;
 741
 742        return 1;
 743}
 744
 745static void std_output(struct grep_opt *opt, const void *buf, size_t size)
 746{
 747        fwrite(buf, size, 1, stdout);
 748}
 749
 750static int grep_buffer_1(struct grep_opt *opt, const char *name,
 751                         char *buf, unsigned long size, int collect_hits)
 752{
 753        char *bol = buf;
 754        unsigned long left = size;
 755        unsigned lno = 1;
 756        unsigned last_hit = 0;
 757        int binary_match_only = 0;
 758        unsigned count = 0;
 759        int try_lookahead = 0;
 760        enum grep_context ctx = GREP_CONTEXT_HEAD;
 761        xdemitconf_t xecfg;
 762
 763        opt->last_shown = 0;
 764
 765        if (!opt->output)
 766                opt->output = std_output;
 767
 768        if (buffer_is_binary(buf, size)) {
 769                switch (opt->binary) {
 770                case GREP_BINARY_DEFAULT:
 771                        binary_match_only = 1;
 772                        break;
 773                case GREP_BINARY_NOMATCH:
 774                        return 0; /* Assume unmatch */
 775                        break;
 776                default:
 777                        break;
 778                }
 779        }
 780
 781        memset(&xecfg, 0, sizeof(xecfg));
 782        if (opt->funcname && !opt->unmatch_name_only && !opt->status_only &&
 783            !opt->name_only && !binary_match_only && !collect_hits) {
 784                struct userdiff_driver *drv = userdiff_find_by_path(name);
 785                if (drv && drv->funcname.pattern) {
 786                        const struct userdiff_funcname *pe = &drv->funcname;
 787                        xdiff_set_find_func(&xecfg, pe->pattern, pe->cflags);
 788                        opt->priv = &xecfg;
 789                }
 790        }
 791        try_lookahead = should_lookahead(opt);
 792
 793        while (left) {
 794                char *eol, ch;
 795                int hit;
 796
 797                /*
 798                 * look_ahead() skips quicly to the line that possibly
 799                 * has the next hit; don't call it if we need to do
 800                 * something more than just skipping the current line
 801                 * in response to an unmatch for the current line.  E.g.
 802                 * inside a post-context window, we will show the current
 803                 * line as a context around the previous hit when it
 804                 * doesn't hit.
 805                 */
 806                if (try_lookahead
 807                    && !(last_hit
 808                         && lno <= last_hit + opt->post_context)
 809                    && look_ahead(opt, &left, &lno, &bol))
 810                        break;
 811                eol = end_of_line(bol, &left);
 812                ch = *eol;
 813                *eol = 0;
 814
 815                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 816                        ctx = GREP_CONTEXT_BODY;
 817
 818                hit = match_line(opt, bol, eol, ctx, collect_hits);
 819                *eol = ch;
 820
 821                if (collect_hits)
 822                        goto next_line;
 823
 824                /* "grep -v -e foo -e bla" should list lines
 825                 * that do not have either, so inversion should
 826                 * be done outside.
 827                 */
 828                if (opt->invert)
 829                        hit = !hit;
 830                if (opt->unmatch_name_only) {
 831                        if (hit)
 832                                return 0;
 833                        goto next_line;
 834                }
 835                if (hit) {
 836                        count++;
 837                        if (opt->status_only)
 838                                return 1;
 839                        if (binary_match_only) {
 840                                opt->output(opt, "Binary file ", 12);
 841                                output_color(opt, name, strlen(name),
 842                                             opt->color_filename);
 843                                opt->output(opt, " matches\n", 9);
 844                                return 1;
 845                        }
 846                        if (opt->name_only) {
 847                                show_name(opt, name);
 848                                return 1;
 849                        }
 850                        /* Hit at this line.  If we haven't shown the
 851                         * pre-context lines, we would need to show them.
 852                         * When asked to do "count", this still show
 853                         * the context which is nonsense, but the user
 854                         * deserves to get that ;-).
 855                         */
 856                        if (opt->pre_context)
 857                                show_pre_context(opt, name, buf, bol, lno);
 858                        else if (opt->funcname)
 859                                show_funcname_line(opt, name, buf, bol, lno);
 860                        if (!opt->count)
 861                                show_line(opt, bol, eol, name, lno, ':');
 862                        last_hit = lno;
 863                }
 864                else if (last_hit &&
 865                         lno <= last_hit + opt->post_context) {
 866                        /* If the last hit is within the post context,
 867                         * we need to show this line.
 868                         */
 869                        show_line(opt, bol, eol, name, lno, '-');
 870                }
 871
 872        next_line:
 873                bol = eol + 1;
 874                if (!left)
 875                        break;
 876                left--;
 877                lno++;
 878        }
 879
 880        if (collect_hits)
 881                return 0;
 882
 883        if (opt->status_only)
 884                return 0;
 885        if (opt->unmatch_name_only) {
 886                /* We did not see any hit, so we want to show this */
 887                show_name(opt, name);
 888                return 1;
 889        }
 890
 891        xdiff_clear_find_func(&xecfg);
 892        opt->priv = NULL;
 893
 894        /* NEEDSWORK:
 895         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 896         * which feels mostly useless but sometimes useful.  Maybe
 897         * make it another option?  For now suppress them.
 898         */
 899        if (opt->count && count) {
 900                char buf[32];
 901                output_color(opt, name, strlen(name), opt->color_filename);
 902                output_sep(opt, ':');
 903                snprintf(buf, sizeof(buf), "%u\n", count);
 904                opt->output(opt, buf, strlen(buf));
 905        }
 906        return !!last_hit;
 907}
 908
 909static void clr_hit_marker(struct grep_expr *x)
 910{
 911        /* All-hit markers are meaningful only at the very top level
 912         * OR node.
 913         */
 914        while (1) {
 915                x->hit = 0;
 916                if (x->node != GREP_NODE_OR)
 917                        return;
 918                x->u.binary.left->hit = 0;
 919                x = x->u.binary.right;
 920        }
 921}
 922
 923static int chk_hit_marker(struct grep_expr *x)
 924{
 925        /* Top level nodes have hit markers.  See if they all are hits */
 926        while (1) {
 927                if (x->node != GREP_NODE_OR)
 928                        return x->hit;
 929                if (!x->u.binary.left->hit)
 930                        return 0;
 931                x = x->u.binary.right;
 932        }
 933}
 934
 935int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 936{
 937        /*
 938         * we do not have to do the two-pass grep when we do not check
 939         * buffer-wide "all-match".
 940         */
 941        if (!opt->all_match)
 942                return grep_buffer_1(opt, name, buf, size, 0);
 943
 944        /* Otherwise the toplevel "or" terms hit a bit differently.
 945         * We first clear hit markers from them.
 946         */
 947        clr_hit_marker(opt->pattern_expression);
 948        grep_buffer_1(opt, name, buf, size, 1);
 949
 950        if (!chk_hit_marker(opt->pattern_expression))
 951                return 0;
 952
 953        return grep_buffer_1(opt, name, buf, size, 0);
 954}