grep.c

   1 #include "cache.h"
   2 #include "grep.h"
   3 #include "userdiff.h"
   4 #include "xdiff-interface.h"
   5 #include "diff.h"
   6 #include "diffcore.h"
   7
   8 static int grep_source_load(struct grep_source *gs);
   9 static int grep_source_is_binary(struct grep_source *gs);
  10
  11 static struct grep_opt grep_defaults;
  12
  13 /*
  14  * Initialize the grep_defaults template with hardcoded defaults.
  15  * We could let the compiler do this, but without C99 initializers
  16  * the code gets unwieldy and unreadable, so...
  17  */
  18 void init_grep_defaults(void)
  19 {
  20         struct grep_opt *opt = &grep_defaults;
  21         static int run_once;
  22
  23         if (run_once)
  24                 return;
  25         run_once++;
  26
  27         memset(opt, 0, sizeof(*opt));
  28         opt->relative = 1;
  29         opt->pathname = 1;
  30         opt->regflags = REG_NEWLINE;
  31         opt->max_depth = -1;
  32         opt->pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
  33         opt->extended_regexp_option = 0;
  34         strcpy(opt->color_context, "");
  35         strcpy(opt->color_filename, "");
  36         strcpy(opt->color_function, "");
  37         strcpy(opt->color_lineno, "");
  38         strcpy(opt->color_match, GIT_COLOR_BOLD_RED);
  39         strcpy(opt->color_selected, "");
  40         strcpy(opt->color_sep, GIT_COLOR_CYAN);
  41         opt->color = -1;
  42 }
  43
  44 static int parse_pattern_type_arg(const char *opt, const char *arg)
  45 {
  46         if (!strcmp(arg, "default"))
  47                 return GREP_PATTERN_TYPE_UNSPECIFIED;
  48         else if (!strcmp(arg, "basic"))
  49                 return GREP_PATTERN_TYPE_BRE;
  50         else if (!strcmp(arg, "extended"))
  51                 return GREP_PATTERN_TYPE_ERE;
  52         else if (!strcmp(arg, "fixed"))
  53                 return GREP_PATTERN_TYPE_FIXED;
  54         else if (!strcmp(arg, "perl"))
  55                 return GREP_PATTERN_TYPE_PCRE;
  56         die("bad %s argument: %s", opt, arg);
  57 }
  58
  59 /*
  60  * Read the configuration file once and store it in
  61  * the grep_defaults template.
  62  */
  63 int grep_config(const char *var, const char *value, void *cb)
  64 {
  65         struct grep_opt *opt = &grep_defaults;
  66         char *color = NULL;
  67
  68         if (userdiff_config(var, value) < 0)
  69                 return -1;
  70
  71         if (!strcmp(var, "grep.extendedregexp")) {
  72                 if (git_config_bool(var, value))
  73                         opt->extended_regexp_option = 1;
  74                 else
  75                         opt->extended_regexp_option = 0;
  76                 return 0;
  77         }
  78
  79         if (!strcmp(var, "grep.patterntype")) {
  80                 opt->pattern_type_option = parse_pattern_type_arg(var, value);
  81                 return 0;
  82         }
  83
  84         if (!strcmp(var, "grep.linenumber")) {
  85                 opt->linenum = git_config_bool(var, value);
  86                 return 0;
  87         }
  88
  89         if (!strcmp(var, "grep.fullname")) {
  90                 opt->relative = !git_config_bool(var, value);
  91                 return 0;
  92         }
  93
  94         if (!strcmp(var, "color.grep"))
  95                 opt->color = git_config_colorbool(var, value);
  96         else if (!strcmp(var, "color.grep.context"))
  97                 color = opt->color_context;
  98         else if (!strcmp(var, "color.grep.filename"))
  99                 color = opt->color_filename;
 100         else if (!strcmp(var, "color.grep.function"))
 101                 color = opt->color_function;
 102         else if (!strcmp(var, "color.grep.linenumber"))
 103                 color = opt->color_lineno;
 104         else if (!strcmp(var, "color.grep.match"))
 105                 color = opt->color_match;
 106         else if (!strcmp(var, "color.grep.selected"))
 107                 color = opt->color_selected;
 108         else if (!strcmp(var, "color.grep.separator"))
 109                 color = opt->color_sep;
 110
 111         if (color) {
 112                 if (!value)
 113                         return config_error_nonbool(var);
 114                 color_parse(value, var, color);
 115         }
 116         return 0;
 117 }
 118
 119 /*
 120  * Initialize one instance of grep_opt and copy the
 121  * default values from the template we read the configuration
 122  * information in an earlier call to git_config(grep_config).
 123  */
 124 void grep_init(struct grep_opt *opt, const char *prefix)
 125 {
 126         struct grep_opt *def = &grep_defaults;
 127
 128         memset(opt, 0, sizeof(*opt));
 129         opt->prefix = prefix;
 130         opt->prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 131         opt->pattern_tail = &opt->pattern_list;
 132         opt->header_tail = &opt->header_list;
 133
 134         opt->color = def->color;
 135         opt->extended_regexp_option = def->extended_regexp_option;
 136         opt->pattern_type_option = def->pattern_type_option;
 137         opt->linenum = def->linenum;
 138         opt->max_depth = def->max_depth;
 139         opt->pathname = def->pathname;
 140         opt->regflags = def->regflags;
 141         opt->relative = def->relative;
 142
 143         strcpy(opt->color_context, def->color_context);
 144         strcpy(opt->color_filename, def->color_filename);
 145         strcpy(opt->color_function, def->color_function);
 146         strcpy(opt->color_lineno, def->color_lineno);
 147         strcpy(opt->color_match, def->color_match);
 148         strcpy(opt->color_selected, def->color_selected);
 149         strcpy(opt->color_sep, def->color_sep);
 150 }
 151
 152 void grep_commit_pattern_type(enum grep_pattern_type pattern_type, struct grep_opt *opt)
 153 {
 154         if (pattern_type != GREP_PATTERN_TYPE_UNSPECIFIED)
 155                 grep_set_pattern_type_option(pattern_type, opt);
 156         else if (opt->pattern_type_option != GREP_PATTERN_TYPE_UNSPECIFIED)
 157                 grep_set_pattern_type_option(opt->pattern_type_option, opt);
 158         else if (opt->extended_regexp_option)
 159                 grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, opt);
 160 }
 161
 162 void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt)
 163 {
 164         switch (pattern_type) {
 165         case GREP_PATTERN_TYPE_UNSPECIFIED:
 166                 /* fall through */
 167
 168         case GREP_PATTERN_TYPE_BRE:
 169                 opt->fixed = 0;
 170                 opt->pcre = 0;
 171                 opt->regflags &= ~REG_EXTENDED;
 172                 break;
 173
 174         case GREP_PATTERN_TYPE_ERE:
 175                 opt->fixed = 0;
 176                 opt->pcre = 0;
 177                 opt->regflags |= REG_EXTENDED;
 178                 break;
 179
 180         case GREP_PATTERN_TYPE_FIXED:
 181                 opt->fixed = 1;
 182                 opt->pcre = 0;
 183                 opt->regflags &= ~REG_EXTENDED;
 184                 break;
 185
 186         case GREP_PATTERN_TYPE_PCRE:
 187                 opt->fixed = 0;
 188                 opt->pcre = 1;
 189                 opt->regflags &= ~REG_EXTENDED;
 190                 break;
 191         }
 192 }
 193
 194 static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 195                                         const char *origin, int no,
 196                                         enum grep_pat_token t,
 197                                         enum grep_header_field field)
 198 {
 199         struct grep_pat *p = xcalloc(1, sizeof(*p));
 200         p->pattern = xmemdupz(pat, patlen);
 201         p->patternlen = patlen;
 202         p->origin = origin;
 203         p->no = no;
 204         p->token = t;
 205         p->field = field;
 206         return p;
 207 }
 208
 209 static void do_append_grep_pat(struct grep_pat ***tail, struct grep_pat *p)
 210 {
 211         **tail = p;
 212         *tail = &p->next;
 213         p->next = NULL;
 214
 215         switch (p->token) {
 216         case GREP_PATTERN: /* atom */
 217         case GREP_PATTERN_HEAD:
 218         case GREP_PATTERN_BODY:
 219                 for (;;) {
 220                         struct grep_pat *new_pat;
 221                         size_t len = 0;
 222                         char *cp = p->pattern + p->patternlen, *nl = NULL;
 223                         while (++len <= p->patternlen) {
 224                                 if (*(--cp) == '\n') {
 225                                         nl = cp;
 226                                         break;
 227                                 }
 228                         }
 229                         if (!nl)
 230                                 break;
 231                         new_pat = create_grep_pat(nl + 1, len - 1, p->origin,
 232                                                   p->no, p->token, p->field);
 233                         new_pat->next = p->next;
 234                         if (!p->next)
 235                                 *tail = &new_pat->next;
 236                         p->next = new_pat;
 237                         *nl = '\0';
 238                         p->patternlen -= len;
 239                 }
 240                 break;
 241         default:
 242                 break;
 243         }
 244 }
 245
 246 void append_header_grep_pattern(struct grep_opt *opt,
 247                                 enum grep_header_field field, const char *pat)
 248 {
 249         struct grep_pat *p = create_grep_pat(pat, strlen(pat), "header", 0,
 250                                              GREP_PATTERN_HEAD, field);
 251         if (field == GREP_HEADER_REFLOG)
 252                 opt->use_reflog_filter = 1;
 253         do_append_grep_pat(&opt->header_tail, p);
 254 }
 255
 256 void append_grep_pattern(struct grep_opt *opt, const char *pat,
 257                          const char *origin, int no, enum grep_pat_token t)
 258 {
 259         append_grep_pat(opt, pat, strlen(pat), origin, no, t);
 260 }
 261
 262 void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
 263                      const char *origin, int no, enum grep_pat_token t)
 264 {
 265         struct grep_pat *p = create_grep_pat(pat, patlen, origin, no, t, 0);
 266         do_append_grep_pat(&opt->pattern_tail, p);
 267 }
 268
 269 struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
 270 {
 271         struct grep_pat *pat;
 272         struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
 273         *ret = *opt;
 274
 275         ret->pattern_list = NULL;
 276         ret->pattern_tail = &ret->pattern_list;
 277
 278         for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
 279         {
 280                 if(pat->token == GREP_PATTERN_HEAD)
 281                         append_header_grep_pattern(ret, pat->field,
 282                                                    pat->pattern);
 283                 else
 284                         append_grep_pat(ret, pat->pattern, pat->patternlen,
 285                                         pat->origin, pat->no, pat->token);
 286         }
 287
 288         return ret;
 289 }
 290
 291 static NORETURN void compile_regexp_failed(const struct grep_pat *p,
 292                 const char *error)
 293 {
 294         char where[1024];
 295
 296         if (p->no)
 297                 sprintf(where, "In '%s' at %d, ", p->origin, p->no);
 298         else if (p->origin)
 299                 sprintf(where, "%s, ", p->origin);
 300         else
 301                 where[0] = 0;
 302
 303         die("%s'%s': %s", where, p->pattern, error);
 304 }
 305
 306 #ifdef USE_LIBPCRE
 307 static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 308 {
 309         const char *error;
 310         int erroffset;
 311         int options = PCRE_MULTILINE;
 312
 313         if (opt->ignore_case)
 314                 options |= PCRE_CASELESS;
 315
 316         p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
 317                         NULL);
 318         if (!p->pcre_regexp)
 319                 compile_regexp_failed(p, error);
 320
 321         p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
 322         if (!p->pcre_extra_info && error)
 323                 die("%s", error);
 324 }
 325
 326 static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 327                 regmatch_t *match, int eflags)
 328 {
 329         int ovector[30], ret, flags = 0;
 330
 331         if (eflags & REG_NOTBOL)
 332                 flags |= PCRE_NOTBOL;
 333
 334         ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
 335                         0, flags, ovector, ARRAY_SIZE(ovector));
 336         if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
 337                 die("pcre_exec failed with error code %d", ret);
 338         if (ret > 0) {
 339                 ret = 0;
 340                 match->rm_so = ovector[0];
 341                 match->rm_eo = ovector[1];
 342         }
 343
 344         return ret;
 345 }
 346
 347 static void free_pcre_regexp(struct grep_pat *p)
 348 {
 349         pcre_free(p->pcre_regexp);
 350         pcre_free(p->pcre_extra_info);
 351 }
 352 #else /* !USE_LIBPCRE */
 353 static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 354 {
 355         die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 356 }
 357
 358 static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 359                 regmatch_t *match, int eflags)
 360 {
 361         return 1;
 362 }
 363
 364 static void free_pcre_regexp(struct grep_pat *p)
 365 {
 366 }
 367 #endif /* !USE_LIBPCRE */
 368
 369 static int is_fixed(const char *s, size_t len)
 370 {
 371         size_t i;
 372
 373         /* regcomp cannot accept patterns with NULs so we
 374          * consider any pattern containing a NUL fixed.
 375          */
 376         if (memchr(s, 0, len))
 377                 return 1;
 378
 379         for (i = 0; i < len; i++) {
 380                 if (is_regex_special(s[i]))
 381                         return 0;
 382         }
 383
 384         return 1;
 385 }
 386
 387 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 388 {
 389         int err;
 390
 391         p->word_regexp = opt->word_regexp;
 392         p->ignore_case = opt->ignore_case;
 393
 394         if (opt->fixed || is_fixed(p->pattern, p->patternlen))
 395                 p->fixed = 1;
 396         else
 397                 p->fixed = 0;
 398
 399         if (p->fixed) {
 400                 if (opt->regflags & REG_ICASE || p->ignore_case)
 401                         p->kws = kwsalloc(tolower_trans_tbl);
 402                 else
 403                         p->kws = kwsalloc(NULL);
 404                 kwsincr(p->kws, p->pattern, p->patternlen);
 405                 kwsprep(p->kws);
 406                 return;
 407         }
 408
 409         if (opt->pcre) {
 410                 compile_pcre_regexp(p, opt);
 411                 return;
 412         }
 413
 414         err = regcomp(&p->regexp, p->pattern, opt->regflags);
 415         if (err) {
 416                 char errbuf[1024];
 417                 regerror(err, &p->regexp, errbuf, 1024);
 418                 regfree(&p->regexp);
 419                 compile_regexp_failed(p, errbuf);
 420         }
 421 }
 422
 423 static struct grep_expr *compile_pattern_or(struct grep_pat **);
 424 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 425 {
 426         struct grep_pat *p;
 427         struct grep_expr *x;
 428
 429         p = *list;
 430         if (!p)
 431                 return NULL;
 432         switch (p->token) {
 433         case GREP_PATTERN: /* atom */
 434         case GREP_PATTERN_HEAD:
 435         case GREP_PATTERN_BODY:
 436                 x = xcalloc(1, sizeof (struct grep_expr));
 437                 x->node = GREP_NODE_ATOM;
 438                 x->u.atom = p;
 439                 *list = p->next;
 440                 return x;
 441         case GREP_OPEN_PAREN:
 442                 *list = p->next;
 443                 x = compile_pattern_or(list);
 444                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 445                         die("unmatched parenthesis");
 446                 *list = (*list)->next;
 447                 return x;
 448         default:
 449                 return NULL;
 450         }
 451 }
 452
 453 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 454 {
 455         struct grep_pat *p;
 456         struct grep_expr *x;
 457
 458         p = *list;
 459         if (!p)
 460                 return NULL;
 461         switch (p->token) {
 462         case GREP_NOT:
 463                 if (!p->next)
 464                         die("--not not followed by pattern expression");
 465                 *list = p->next;
 466                 x = xcalloc(1, sizeof (struct grep_expr));
 467                 x->node = GREP_NODE_NOT;
 468                 x->u.unary = compile_pattern_not(list);
 469                 if (!x->u.unary)
 470                         die("--not followed by non pattern expression");
 471                 return x;
 472         default:
 473                 return compile_pattern_atom(list);
 474         }
 475 }
 476
 477 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 478 {
 479         struct grep_pat *p;
 480         struct grep_expr *x, *y, *z;
 481
 482         x = compile_pattern_not(list);
 483         p = *list;
 484         if (p && p->token == GREP_AND) {
 485                 if (!p->next)
 486                         die("--and not followed by pattern expression");
 487                 *list = p->next;
 488                 y = compile_pattern_and(list);
 489                 if (!y)
 490                         die("--and not followed by pattern expression");
 491                 z = xcalloc(1, sizeof (struct grep_expr));
 492                 z->node = GREP_NODE_AND;
 493                 z->u.binary.left = x;
 494                 z->u.binary.right = y;
 495                 return z;
 496         }
 497         return x;
 498 }
 499
 500 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 501 {
 502         struct grep_pat *p;
 503         struct grep_expr *x, *y, *z;
 504
 505         x = compile_pattern_and(list);
 506         p = *list;
 507         if (x && p && p->token != GREP_CLOSE_PAREN) {
 508                 y = compile_pattern_or(list);
 509                 if (!y)
 510                         die("not a pattern expression %s", p->pattern);
 511                 z = xcalloc(1, sizeof (struct grep_expr));
 512                 z->node = GREP_NODE_OR;
 513                 z->u.binary.left = x;
 514                 z->u.binary.right = y;
 515                 return z;
 516         }
 517         return x;
 518 }
 519
 520 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 521 {
 522         return compile_pattern_or(list);
 523 }
 524
 525 static void indent(int in)
 526 {
 527         while (in-- > 0)
 528                 fputc(' ', stderr);
 529 }
 530
 531 static void dump_grep_pat(struct grep_pat *p)
 532 {
 533         switch (p->token) {
 534         case GREP_AND: fprintf(stderr, "*and*"); break;
 535         case GREP_OPEN_PAREN: fprintf(stderr, "*(*"); break;
 536         case GREP_CLOSE_PAREN: fprintf(stderr, "*)*"); break;
 537         case GREP_NOT: fprintf(stderr, "*not*"); break;
 538         case GREP_OR: fprintf(stderr, "*or*"); break;
 539
 540         case GREP_PATTERN: fprintf(stderr, "pattern"); break;
 541         case GREP_PATTERN_HEAD: fprintf(stderr, "pattern_head"); break;
 542         case GREP_PATTERN_BODY: fprintf(stderr, "pattern_body"); break;
 543         }
 544
 545         switch (p->token) {
 546         default: break;
 547         case GREP_PATTERN_HEAD:
 548                 fprintf(stderr, "<head %d>", p->field); break;
 549         case GREP_PATTERN_BODY:
 550                 fprintf(stderr, "<body>"); break;
 551         }
 552         switch (p->token) {
 553         default: break;
 554         case GREP_PATTERN_HEAD:
 555         case GREP_PATTERN_BODY:
 556         case GREP_PATTERN:
 557                 fprintf(stderr, "%.*s", (int)p->patternlen, p->pattern);
 558                 break;
 559         }
 560         fputc('\n', stderr);
 561 }
 562
 563 static void dump_grep_expression_1(struct grep_expr *x, int in)
 564 {
 565         indent(in);
 566         switch (x->node) {
 567         case GREP_NODE_TRUE:
 568                 fprintf(stderr, "true\n");
 569                 break;
 570         case GREP_NODE_ATOM:
 571                 dump_grep_pat(x->u.atom);
 572                 break;
 573         case GREP_NODE_NOT:
 574                 fprintf(stderr, "(not\n");
 575                 dump_grep_expression_1(x->u.unary, in+1);
 576                 indent(in);
 577                 fprintf(stderr, ")\n");
 578                 break;
 579         case GREP_NODE_AND:
 580                 fprintf(stderr, "(and\n");
 581                 dump_grep_expression_1(x->u.binary.left, in+1);
 582                 dump_grep_expression_1(x->u.binary.right, in+1);
 583                 indent(in);
 584                 fprintf(stderr, ")\n");
 585                 break;
 586         case GREP_NODE_OR:
 587                 fprintf(stderr, "(or\n");
 588                 dump_grep_expression_1(x->u.binary.left, in+1);
 589                 dump_grep_expression_1(x->u.binary.right, in+1);
 590                 indent(in);
 591                 fprintf(stderr, ")\n");
 592                 break;
 593         }
 594 }
 595
 596 static void dump_grep_expression(struct grep_opt *opt)
 597 {
 598         struct grep_expr *x = opt->pattern_expression;
 599
 600         if (opt->all_match)
 601                 fprintf(stderr, "[all-match]\n");
 602         dump_grep_expression_1(x, 0);
 603         fflush(NULL);
 604 }
 605
 606 static struct grep_expr *grep_true_expr(void)
 607 {
 608         struct grep_expr *z = xcalloc(1, sizeof(*z));
 609         z->node = GREP_NODE_TRUE;
 610         return z;
 611 }
 612
 613 static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 614 {
 615         struct grep_expr *z = xcalloc(1, sizeof(*z));
 616         z->node = GREP_NODE_OR;
 617         z->u.binary.left = left;
 618         z->u.binary.right = right;
 619         return z;
 620 }
 621
 622 static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 623 {
 624         struct grep_pat *p;
 625         struct grep_expr *header_expr;
 626         struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 627         enum grep_header_field fld;
 628
 629         if (!opt->header_list)
 630                 return NULL;
 631
 632         for (p = opt->header_list; p; p = p->next) {
 633                 if (p->token != GREP_PATTERN_HEAD)
 634                         die("bug: a non-header pattern in grep header list.");
 635                 if (p->field < GREP_HEADER_FIELD_MIN ||
 636                     GREP_HEADER_FIELD_MAX <= p->field)
 637                         die("bug: unknown header field %d", p->field);
 638                 compile_regexp(p, opt);
 639         }
 640
 641         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 642                 header_group[fld] = NULL;
 643
 644         for (p = opt->header_list; p; p = p->next) {
 645                 struct grep_expr *h;
 646                 struct grep_pat *pp = p;
 647
 648                 h = compile_pattern_atom(&pp);
 649                 if (!h || pp != p->next)
 650                         die("bug: malformed header expr");
 651                 if (!header_group[p->field]) {
 652                         header_group[p->field] = h;
 653                         continue;
 654                 }
 655                 header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 656         }
 657
 658         header_expr = NULL;
 659
 660         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 661                 if (!header_group[fld])
 662                         continue;
 663                 if (!header_expr)
 664                         header_expr = grep_true_expr();
 665                 header_expr = grep_or_expr(header_group[fld], header_expr);
 666         }
 667         return header_expr;
 668 }
 669
 670 static struct grep_expr *grep_splice_or(struct grep_expr *x, struct grep_expr *y)
 671 {
 672         struct grep_expr *z = x;
 673
 674         while (x) {
 675                 assert(x->node == GREP_NODE_OR);
 676                 if (x->u.binary.right &&
 677                     x->u.binary.right->node == GREP_NODE_TRUE) {
 678                         x->u.binary.right = y;
 679                         break;
 680                 }
 681                 x = x->u.binary.right;
 682         }
 683         return z;
 684 }
 685
 686 static void compile_grep_patterns_real(struct grep_opt *opt)
 687 {
 688         struct grep_pat *p;
 689         struct grep_expr *header_expr = prep_header_patterns(opt);
 690
 691         for (p = opt->pattern_list; p; p = p->next) {
 692                 switch (p->token) {
 693                 case GREP_PATTERN: /* atom */
 694                 case GREP_PATTERN_HEAD:
 695                 case GREP_PATTERN_BODY:
 696                         compile_regexp(p, opt);
 697                         break;
 698                 default:
 699                         opt->extended = 1;
 700                         break;
 701                 }
 702         }
 703
 704         if (opt->all_match || header_expr)
 705                 opt->extended = 1;
 706         else if (!opt->extended && !opt->debug)
 707                 return;
 708
 709         p = opt->pattern_list;
 710         if (p)
 711                 opt->pattern_expression = compile_pattern_expr(&p);
 712         if (p)
 713                 die("incomplete pattern expression: %s", p->pattern);
 714
 715         if (!header_expr)
 716                 return;
 717
 718         if (!opt->pattern_expression)
 719                 opt->pattern_expression = header_expr;
 720         else if (opt->all_match)
 721                 opt->pattern_expression = grep_splice_or(header_expr,
 722                                                          opt->pattern_expression);
 723         else
 724                 opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 725                                                        header_expr);
 726         opt->all_match = 1;
 727 }
 728
 729 void compile_grep_patterns(struct grep_opt *opt)
 730 {
 731         compile_grep_patterns_real(opt);
 732         if (opt->debug)
 733                 dump_grep_expression(opt);
 734 }
 735
 736 static void free_pattern_expr(struct grep_expr *x)
 737 {
 738         switch (x->node) {
 739         case GREP_NODE_TRUE:
 740         case GREP_NODE_ATOM:
 741                 break;
 742         case GREP_NODE_NOT:
 743                 free_pattern_expr(x->u.unary);
 744                 break;
 745         case GREP_NODE_AND:
 746         case GREP_NODE_OR:
 747                 free_pattern_expr(x->u.binary.left);
 748                 free_pattern_expr(x->u.binary.right);
 749                 break;
 750         }
 751         free(x);
 752 }
 753
 754 void free_grep_patterns(struct grep_opt *opt)
 755 {
 756         struct grep_pat *p, *n;
 757
 758         for (p = opt->pattern_list; p; p = n) {
 759                 n = p->next;
 760                 switch (p->token) {
 761                 case GREP_PATTERN: /* atom */
 762                 case GREP_PATTERN_HEAD:
 763                 case GREP_PATTERN_BODY:
 764                         if (p->kws)
 765                                 kwsfree(p->kws);
 766                         else if (p->pcre_regexp)
 767                                 free_pcre_regexp(p);
 768                         else
 769                                 regfree(&p->regexp);
 770                         free(p->pattern);
 771                         break;
 772                 default:
 773                         break;
 774                 }
 775                 free(p);
 776         }
 777
 778         if (!opt->extended)
 779                 return;
 780         free_pattern_expr(opt->pattern_expression);
 781 }
 782
 783 static char *end_of_line(char *cp, unsigned long *left)
 784 {
 785         unsigned long l = *left;
 786         while (l && *cp != '\n') {
 787                 l--;
 788                 cp++;
 789         }
 790         *left = l;
 791         return cp;
 792 }
 793
 794 static int word_char(char ch)
 795 {
 796         return isalnum(ch) || ch == '_';
 797 }
 798
 799 static void output_color(struct grep_opt *opt, const void *data, size_t size,
 800                          const char *color)
 801 {
 802         if (want_color(opt->color) && color && color[0]) {
 803                 opt->output(opt, color, strlen(color));
 804                 opt->output(opt, data, size);
 805                 opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 806         } else
 807                 opt->output(opt, data, size);
 808 }
 809
 810 static void output_sep(struct grep_opt *opt, char sign)
 811 {
 812         if (opt->null_following_name)
 813                 opt->output(opt, "\0", 1);
 814         else
 815                 output_color(opt, &sign, 1, opt->color_sep);
 816 }
 817
 818 static void show_name(struct grep_opt *opt, const char *name)
 819 {
 820         output_color(opt, name, strlen(name), opt->color_filename);
 821         opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 822 }
 823
 824 static int fixmatch(struct grep_pat *p, char *line, char *eol,
 825                     regmatch_t *match)
 826 {
 827         struct kwsmatch kwsm;
 828         size_t offset = kwsexec(p->kws, line, eol - line, &kwsm);
 829         if (offset == -1) {
 830                 match->rm_so = match->rm_eo = -1;
 831                 return REG_NOMATCH;
 832         } else {
 833                 match->rm_so = offset;
 834                 match->rm_eo = match->rm_so + kwsm.size[0];
 835                 return 0;
 836         }
 837 }
 838
 839 static int regmatch(const regex_t *preg, char *line, char *eol,
 840                     regmatch_t *match, int eflags)
 841 {
 842 #ifdef REG_STARTEND
 843         match->rm_so = 0;
 844         match->rm_eo = eol - line;
 845         eflags |= REG_STARTEND;
 846 #endif
 847         return regexec(preg, line, 1, match, eflags);
 848 }
 849
 850 static int patmatch(struct grep_pat *p, char *line, char *eol,
 851                     regmatch_t *match, int eflags)
 852 {
 853         int hit;
 854
 855         if (p->fixed)
 856                 hit = !fixmatch(p, line, eol, match);
 857         else if (p->pcre_regexp)
 858                 hit = !pcrematch(p, line, eol, match, eflags);
 859         else
 860                 hit = !regmatch(&p->regexp, line, eol, match, eflags);
 861
 862         return hit;
 863 }
 864
 865 static int strip_timestamp(char *bol, char **eol_p)
 866 {
 867         char *eol = *eol_p;
 868         int ch;
 869
 870         while (bol < --eol) {
 871                 if (*eol != '>')
 872                         continue;
 873                 *eol_p = ++eol;
 874                 ch = *eol;
 875                 *eol = '\0';
 876                 return ch;
 877         }
 878         return 0;
 879 }
 880
 881 static struct {
 882         const char *field;
 883         size_t len;
 884 } header_field[] = {
 885         { "author ", 7 },
 886         { "committer ", 10 },
 887         { "reflog ", 7 },
 888 };
 889
 890 static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 891                              enum grep_context ctx,
 892                              regmatch_t *pmatch, int eflags)
 893 {
 894         int hit = 0;
 895         int saved_ch = 0;
 896         const char *start = bol;
 897
 898         if ((p->token != GREP_PATTERN) &&
 899             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 900                 return 0;
 901
 902         if (p->token == GREP_PATTERN_HEAD) {
 903                 const char *field;
 904                 size_t len;
 905                 assert(p->field < ARRAY_SIZE(header_field));
 906                 field = header_field[p->field].field;
 907                 len = header_field[p->field].len;
 908                 if (strncmp(bol, field, len))
 909                         return 0;
 910                 bol += len;
 911                 switch (p->field) {
 912                 case GREP_HEADER_AUTHOR:
 913                 case GREP_HEADER_COMMITTER:
 914                         saved_ch = strip_timestamp(bol, &eol);
 915                         break;
 916                 default:
 917                         break;
 918                 }
 919         }
 920
 921  again:
 922         hit = patmatch(p, bol, eol, pmatch, eflags);
 923
 924         if (hit && p->word_regexp) {
 925                 if ((pmatch[0].rm_so < 0) ||
 926                     (eol - bol) < pmatch[0].rm_so ||
 927                     (pmatch[0].rm_eo < 0) ||
 928                     (eol - bol) < pmatch[0].rm_eo)
 929                         die("regexp returned nonsense");
 930
 931                 /* Match beginning must be either beginning of the
 932                  * line, or at word boundary (i.e. the last char must
 933                  * not be a word char).  Similarly, match end must be
 934                  * either end of the line, or at word boundary
 935                  * (i.e. the next char must not be a word char).
 936                  */
 937                 if ( ((pmatch[0].rm_so == 0) ||
 938                       !word_char(bol[pmatch[0].rm_so-1])) &&
 939                      ((pmatch[0].rm_eo == (eol-bol)) ||
 940                       !word_char(bol[pmatch[0].rm_eo])) )
 941                         ;
 942                 else
 943                         hit = 0;
 944
 945                 /* Words consist of at least one character. */
 946                 if (pmatch->rm_so == pmatch->rm_eo)
 947                         hit = 0;
 948
 949                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 950                         /* There could be more than one match on the
 951                          * line, and the first match might not be
 952                          * strict word match.  But later ones could be!
 953                          * Forward to the next possible start, i.e. the
 954                          * next position following a non-word char.
 955                          */
 956                         bol = pmatch[0].rm_so + bol + 1;
 957                         while (word_char(bol[-1]) && bol < eol)
 958                                 bol++;
 959                         eflags |= REG_NOTBOL;
 960                         if (bol < eol)
 961                                 goto again;
 962                 }
 963         }
 964         if (p->token == GREP_PATTERN_HEAD && saved_ch)
 965                 *eol = saved_ch;
 966         if (hit) {
 967                 pmatch[0].rm_so += bol - start;
 968                 pmatch[0].rm_eo += bol - start;
 969         }
 970         return hit;
 971 }
 972
 973 static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
 974                            enum grep_context ctx, int collect_hits)
 975 {
 976         int h = 0;
 977         regmatch_t match;
 978
 979         if (!x)
 980                 die("Not a valid grep expression");
 981         switch (x->node) {
 982         case GREP_NODE_TRUE:
 983                 h = 1;
 984                 break;
 985         case GREP_NODE_ATOM:
 986                 h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
 987                 break;
 988         case GREP_NODE_NOT:
 989                 h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
 990                 break;
 991         case GREP_NODE_AND:
 992                 if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
 993                         return 0;
 994                 h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
 995                 break;
 996         case GREP_NODE_OR:
 997                 if (!collect_hits)
 998                         return (match_expr_eval(x->u.binary.left,
 999                                                 bol, eol, ctx, 0) ||
1000                                 match_expr_eval(x->u.binary.right,
1001                                                 bol, eol, ctx, 0));
1002                 h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
1003                 x->u.binary.left->hit |= h;
1004                 h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
1005                 break;
1006         default:
1007                 die("Unexpected node type (internal error) %d", x->node);
1008         }
1009         if (collect_hits)
1010                 x->hit |= h;
1011         return h;
1012 }
1013
1014 static int match_expr(struct grep_opt *opt, char *bol, char *eol,
1015                       enum grep_context ctx, int collect_hits)
1016 {
1017         struct grep_expr *x = opt->pattern_expression;
1018         return match_expr_eval(x, bol, eol, ctx, collect_hits);
1019 }
1020
1021 static int match_line(struct grep_opt *opt, char *bol, char *eol,
1022                       enum grep_context ctx, int collect_hits)
1023 {
1024         struct grep_pat *p;
1025         regmatch_t match;
1026
1027         if (opt->extended)
1028                 return match_expr(opt, bol, eol, ctx, collect_hits);
1029
1030         /* we do not call with collect_hits without being extended */
1031         for (p = opt->pattern_list; p; p = p->next) {
1032                 if (match_one_pattern(p, bol, eol, ctx, &match, 0))
1033                         return 1;
1034         }
1035         return 0;
1036 }
1037
1038 static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
1039                               enum grep_context ctx,
1040                               regmatch_t *pmatch, int eflags)
1041 {
1042         regmatch_t match;
1043
1044         if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
1045                 return 0;
1046         if (match.rm_so < 0 || match.rm_eo < 0)
1047                 return 0;
1048         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
1049                 if (match.rm_so > pmatch->rm_so)
1050                         return 1;
1051                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
1052                         return 1;
1053         }
1054         pmatch->rm_so = match.rm_so;
1055         pmatch->rm_eo = match.rm_eo;
1056         return 1;
1057 }
1058
1059 static int next_match(struct grep_opt *opt, char *bol, char *eol,
1060                       enum grep_context ctx, regmatch_t *pmatch, int eflags)
1061 {
1062         struct grep_pat *p;
1063         int hit = 0;
1064
1065         pmatch->rm_so = pmatch->rm_eo = -1;
1066         if (bol < eol) {
1067                 for (p = opt->pattern_list; p; p = p->next) {
1068                         switch (p->token) {
1069                         case GREP_PATTERN: /* atom */
1070                         case GREP_PATTERN_HEAD:
1071                         case GREP_PATTERN_BODY:
1072                                 hit |= match_next_pattern(p, bol, eol, ctx,
1073                                                           pmatch, eflags);
1074                                 break;
1075                         default:
1076                                 break;
1077                         }
1078                 }
1079         }
1080         return hit;
1081 }
1082
1083 static void show_line(struct grep_opt *opt, char *bol, char *eol,
1084                       const char *name, unsigned lno, char sign)
1085 {
1086         int rest = eol - bol;
1087         char *line_color = NULL;
1088
1089         if (opt->file_break && opt->last_shown == 0) {
1090                 if (opt->show_hunk_mark)
1091                         opt->output(opt, "\n", 1);
1092         } else if (opt->pre_context || opt->post_context || opt->funcbody) {
1093                 if (opt->last_shown == 0) {
1094                         if (opt->show_hunk_mark) {
1095                                 output_color(opt, "--", 2, opt->color_sep);
1096                                 opt->output(opt, "\n", 1);
1097                         }
1098                 } else if (lno > opt->last_shown + 1) {
1099                         output_color(opt, "--", 2, opt->color_sep);
1100                         opt->output(opt, "\n", 1);
1101                 }
1102         }
1103         if (opt->heading && opt->last_shown == 0) {
1104                 output_color(opt, name, strlen(name), opt->color_filename);
1105                 opt->output(opt, "\n", 1);
1106         }
1107         opt->last_shown = lno;
1108
1109         if (!opt->heading && opt->pathname) {
1110                 output_color(opt, name, strlen(name), opt->color_filename);
1111                 output_sep(opt, sign);
1112         }
1113         if (opt->linenum) {
1114                 char buf[32];
1115                 snprintf(buf, sizeof(buf), "%d", lno);
1116                 output_color(opt, buf, strlen(buf), opt->color_lineno);
1117                 output_sep(opt, sign);
1118         }
1119         if (opt->color) {
1120                 regmatch_t match;
1121                 enum grep_context ctx = GREP_CONTEXT_BODY;
1122                 int ch = *eol;
1123                 int eflags = 0;
1124
1125                 if (sign == ':')
1126                         line_color = opt->color_selected;
1127                 else if (sign == '-')
1128                         line_color = opt->color_context;
1129                 else if (sign == '=')
1130                         line_color = opt->color_function;
1131                 *eol = '\0';
1132                 while (next_match(opt, bol, eol, ctx, &match, eflags)) {
1133                         if (match.rm_so == match.rm_eo)
1134                                 break;
1135
1136                         output_color(opt, bol, match.rm_so, line_color);
1137                         output_color(opt, bol + match.rm_so,
1138                                      match.rm_eo - match.rm_so,
1139                                      opt->color_match);
1140                         bol += match.rm_eo;
1141                         rest -= match.rm_eo;
1142                         eflags = REG_NOTBOL;
1143                 }
1144                 *eol = ch;
1145         }
1146         output_color(opt, bol, rest, line_color);
1147         opt->output(opt, "\n", 1);
1148 }
1149
1150 #ifndef NO_PTHREADS
1151 int grep_use_locks;
1152
1153 /*
1154  * This lock protects access to the gitattributes machinery, which is
1155  * not thread-safe.
1156  */
1157 pthread_mutex_t grep_attr_mutex;
1158
1159 static inline void grep_attr_lock(void)
1160 {
1161         if (grep_use_locks)
1162                 pthread_mutex_lock(&grep_attr_mutex);
1163 }
1164
1165 static inline void grep_attr_unlock(void)
1166 {
1167         if (grep_use_locks)
1168                 pthread_mutex_unlock(&grep_attr_mutex);
1169 }
1170
1171 /*
1172  * Same as git_attr_mutex, but protecting the thread-unsafe object db access.
1173  */
1174 pthread_mutex_t grep_read_mutex;
1175
1176 #else
1177 #define grep_attr_lock()
1178 #define grep_attr_unlock()
1179 #endif
1180
1181 static int match_funcname(struct grep_opt *opt, struct grep_source *gs, char *bol, char *eol)
1182 {
1183         xdemitconf_t *xecfg = opt->priv;
1184         if (xecfg && !xecfg->find_func) {
1185                 grep_source_load_driver(gs);
1186                 if (gs->driver->funcname.pattern) {
1187                         const struct userdiff_funcname *pe = &gs->driver->funcname;
1188                         xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
1189                 } else {
1190                         xecfg = opt->priv = NULL;
1191                 }
1192         }
1193
1194         if (xecfg) {
1195                 char buf[1];
1196                 return xecfg->find_func(bol, eol - bol, buf, 1,
1197                                         xecfg->find_func_priv) >= 0;
1198         }
1199
1200         if (bol == eol)
1201                 return 0;
1202         if (isalpha(*bol) || *bol == '_' || *bol == '$')
1203                 return 1;
1204         return 0;
1205 }
1206
1207 static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
1208                                char *bol, unsigned lno)
1209 {
1210         while (bol > gs->buf) {
1211                 char *eol = --bol;
1212
1213                 while (bol > gs->buf && bol[-1] != '\n')
1214                         bol--;
1215                 lno--;
1216
1217                 if (lno <= opt->last_shown)
1218                         break;
1219
1220                 if (match_funcname(opt, gs, bol, eol)) {
1221                         show_line(opt, bol, eol, gs->name, lno, '=');
1222                         break;
1223                 }
1224         }
1225 }
1226
1227 static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
1228                              char *bol, char *end, unsigned lno)
1229 {
1230         unsigned cur = lno, from = 1, funcname_lno = 0;
1231         int funcname_needed = !!opt->funcname;
1232
1233         if (opt->funcbody && !match_funcname(opt, gs, bol, end))
1234                 funcname_needed = 2;
1235
1236         if (opt->pre_context < lno)
1237                 from = lno - opt->pre_context;
1238         if (from <= opt->last_shown)
1239                 from = opt->last_shown + 1;
1240
1241         /* Rewind. */
1242         while (bol > gs->buf &&
1243                cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
1244                 char *eol = --bol;
1245
1246                 while (bol > gs->buf && bol[-1] != '\n')
1247                         bol--;
1248                 cur--;
1249                 if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
1250                         funcname_lno = cur;
1251                         funcname_needed = 0;
1252                 }
1253         }
1254
1255         /* We need to look even further back to find a function signature. */
1256         if (opt->funcname && funcname_needed)
1257                 show_funcname_line(opt, gs, bol, cur);
1258
1259         /* Back forward. */
1260         while (cur < lno) {
1261                 char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
1262
1263                 while (*eol != '\n')
1264                         eol++;
1265                 show_line(opt, bol, eol, gs->name, cur, sign);
1266                 bol = eol + 1;
1267                 cur++;
1268         }
1269 }
1270
1271 static int should_lookahead(struct grep_opt *opt)
1272 {
1273         struct grep_pat *p;
1274
1275         if (opt->extended)
1276                 return 0; /* punt for too complex stuff */
1277         if (opt->invert)
1278                 return 0;
1279         for (p = opt->pattern_list; p; p = p->next) {
1280                 if (p->token != GREP_PATTERN)
1281                         return 0; /* punt for "header only" and stuff */
1282         }
1283         return 1;
1284 }
1285
1286 static int look_ahead(struct grep_opt *opt,
1287                       unsigned long *left_p,
1288                       unsigned *lno_p,
1289                       char **bol_p)
1290 {
1291         unsigned lno = *lno_p;
1292         char *bol = *bol_p;
1293         struct grep_pat *p;
1294         char *sp, *last_bol;
1295         regoff_t earliest = -1;
1296
1297         for (p = opt->pattern_list; p; p = p->next) {
1298                 int hit;
1299                 regmatch_t m;
1300
1301                 hit = patmatch(p, bol, bol + *left_p, &m, 0);
1302                 if (!hit || m.rm_so < 0 || m.rm_eo < 0)
1303                         continue;
1304                 if (earliest < 0 || m.rm_so < earliest)
1305                         earliest = m.rm_so;
1306         }
1307
1308         if (earliest < 0) {
1309                 *bol_p = bol + *left_p;
1310                 *left_p = 0;
1311                 return 1;
1312         }
1313         for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
1314                 ; /* find the beginning of the line */
1315         last_bol = sp;
1316
1317         for (sp = bol; sp < last_bol; sp++) {
1318                 if (*sp == '\n')
1319                         lno++;
1320         }
1321         *left_p -= last_bol - bol;
1322         *bol_p = last_bol;
1323         *lno_p = lno;
1324         return 0;
1325 }
1326
1327 static void std_output(struct grep_opt *opt, const void *buf, size_t size)
1328 {
1329         fwrite(buf, size, 1, stdout);
1330 }
1331
1332 static int fill_textconv_grep(struct userdiff_driver *driver,
1333                               struct grep_source *gs)
1334 {
1335         struct diff_filespec *df;
1336         char *buf;
1337         size_t size;
1338
1339         if (!driver || !driver->textconv)
1340                 return grep_source_load(gs);
1341
1342         /*
1343          * The textconv interface is intimately tied to diff_filespecs, so we
1344          * have to pretend to be one. If we could unify the grep_source
1345          * and diff_filespec structs, this mess could just go away.
1346          */
1347         df = alloc_filespec(gs->path);
1348         switch (gs->type) {
1349         case GREP_SOURCE_SHA1:
1350                 fill_filespec(df, gs->identifier, 1, 0100644);
1351                 break;
1352         case GREP_SOURCE_FILE:
1353                 fill_filespec(df, null_sha1, 0, 0100644);
1354                 break;
1355         default:
1356                 die("BUG: attempt to textconv something without a path?");
1357         }
1358
1359         /*
1360          * fill_textconv is not remotely thread-safe; it may load objects
1361          * behind the scenes, and it modifies the global diff tempfile
1362          * structure.
1363          */
1364         grep_read_lock();
1365         size = fill_textconv(driver, df, &buf);
1366         grep_read_unlock();
1367         free_filespec(df);
1368
1369         /*
1370          * The normal fill_textconv usage by the diff machinery would just keep
1371          * the textconv'd buf separate from the diff_filespec. But much of the
1372          * grep code passes around a grep_source and assumes that its "buf"
1373          * pointer is the beginning of the thing we are searching. So let's
1374          * install our textconv'd version into the grep_source, taking care not
1375          * to leak any existing buffer.
1376          */
1377         grep_source_clear_data(gs);
1378         gs->buf = buf;
1379         gs->size = size;
1380
1381         return 0;
1382 }
1383
1384 static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int collect_hits)
1385 {
1386         char *bol;
1387         unsigned long left;
1388         unsigned lno = 1;
1389         unsigned last_hit = 0;
1390         int binary_match_only = 0;
1391         unsigned count = 0;
1392         int try_lookahead = 0;
1393         int show_function = 0;
1394         struct userdiff_driver *textconv = NULL;
1395         enum grep_context ctx = GREP_CONTEXT_HEAD;
1396         xdemitconf_t xecfg;
1397
1398         if (!opt->output)
1399                 opt->output = std_output;
1400
1401         if (opt->pre_context || opt->post_context || opt->file_break ||
1402             opt->funcbody) {
1403                 /* Show hunk marks, except for the first file. */
1404                 if (opt->last_shown)
1405                         opt->show_hunk_mark = 1;
1406                 /*
1407                  * If we're using threads then we can't easily identify
1408                  * the first file.  Always put hunk marks in that case
1409                  * and skip the very first one later in work_done().
1410                  */
1411                 if (opt->output != std_output)
1412                         opt->show_hunk_mark = 1;
1413         }
1414         opt->last_shown = 0;
1415
1416         if (opt->allow_textconv) {
1417                 grep_source_load_driver(gs);
1418                 /*
1419                  * We might set up the shared textconv cache data here, which
1420                  * is not thread-safe.
1421                  */
1422                 grep_attr_lock();
1423                 textconv = userdiff_get_textconv(gs->driver);
1424                 grep_attr_unlock();
1425         }
1426
1427         /*
1428          * We know the result of a textconv is text, so we only have to care
1429          * about binary handling if we are not using it.
1430          */
1431         if (!textconv) {
1432                 switch (opt->binary) {
1433                 case GREP_BINARY_DEFAULT:
1434                         if (grep_source_is_binary(gs))
1435                                 binary_match_only = 1;
1436                         break;
1437                 case GREP_BINARY_NOMATCH:
1438                         if (grep_source_is_binary(gs))
1439                                 return 0; /* Assume unmatch */
1440                         break;
1441                 case GREP_BINARY_TEXT:
1442                         break;
1443                 default:
1444                         die("bug: unknown binary handling mode");
1445                 }
1446         }
1447
1448         memset(&xecfg, 0, sizeof(xecfg));
1449         opt->priv = &xecfg;
1450
1451         try_lookahead = should_lookahead(opt);
1452
1453         if (fill_textconv_grep(textconv, gs) < 0)
1454                 return 0;
1455
1456         bol = gs->buf;
1457         left = gs->size;
1458         while (left) {
1459                 char *eol, ch;
1460                 int hit;
1461
1462                 /*
1463                  * look_ahead() skips quickly to the line that possibly
1464                  * has the next hit; don't call it if we need to do
1465                  * something more than just skipping the current line
1466                  * in response to an unmatch for the current line.  E.g.
1467                  * inside a post-context window, we will show the current
1468                  * line as a context around the previous hit when it
1469                  * doesn't hit.
1470                  */
1471                 if (try_lookahead
1472                     && !(last_hit
1473                          && (show_function ||
1474                              lno <= last_hit + opt->post_context))
1475                     && look_ahead(opt, &left, &lno, &bol))
1476                         break;
1477                 eol = end_of_line(bol, &left);
1478                 ch = *eol;
1479                 *eol = 0;
1480
1481                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1482                         ctx = GREP_CONTEXT_BODY;
1483
1484                 hit = match_line(opt, bol, eol, ctx, collect_hits);
1485                 *eol = ch;
1486
1487                 if (collect_hits)
1488                         goto next_line;
1489
1490                 /* "grep -v -e foo -e bla" should list lines
1491                  * that do not have either, so inversion should
1492                  * be done outside.
1493                  */
1494                 if (opt->invert)
1495                         hit = !hit;
1496                 if (opt->unmatch_name_only) {
1497                         if (hit)
1498                                 return 0;
1499                         goto next_line;
1500                 }
1501                 if (hit) {
1502                         count++;
1503                         if (opt->status_only)
1504                                 return 1;
1505                         if (opt->name_only) {
1506                                 show_name(opt, gs->name);
1507                                 return 1;
1508                         }
1509                         if (opt->count)
1510                                 goto next_line;
1511                         if (binary_match_only) {
1512                                 opt->output(opt, "Binary file ", 12);
1513                                 output_color(opt, gs->name, strlen(gs->name),
1514                                              opt->color_filename);
1515                                 opt->output(opt, " matches\n", 9);
1516                                 return 1;
1517                         }
1518                         /* Hit at this line.  If we haven't shown the
1519                          * pre-context lines, we would need to show them.
1520                          */
1521                         if (opt->pre_context || opt->funcbody)
1522                                 show_pre_context(opt, gs, bol, eol, lno);
1523                         else if (opt->funcname)
1524                                 show_funcname_line(opt, gs, bol, lno);
1525                         show_line(opt, bol, eol, gs->name, lno, ':');
1526                         last_hit = lno;
1527                         if (opt->funcbody)
1528                                 show_function = 1;
1529                         goto next_line;
1530                 }
1531                 if (show_function && match_funcname(opt, gs, bol, eol))
1532                         show_function = 0;
1533                 if (show_function ||
1534                     (last_hit && lno <= last_hit + opt->post_context)) {
1535                         /* If the last hit is within the post context,
1536                          * we need to show this line.
1537                          */
1538                         show_line(opt, bol, eol, gs->name, lno, '-');
1539                 }
1540
1541         next_line:
1542                 bol = eol + 1;
1543                 if (!left)
1544                         break;
1545                 left--;
1546                 lno++;
1547         }
1548
1549         if (collect_hits)
1550                 return 0;
1551
1552         if (opt->status_only)
1553                 return 0;
1554         if (opt->unmatch_name_only) {
1555                 /* We did not see any hit, so we want to show this */
1556                 show_name(opt, gs->name);
1557                 return 1;
1558         }
1559
1560         xdiff_clear_find_func(&xecfg);
1561         opt->priv = NULL;
1562
1563         /* NEEDSWORK:
1564          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1565          * which feels mostly useless but sometimes useful.  Maybe
1566          * make it another option?  For now suppress them.
1567          */
1568         if (opt->count && count) {
1569                 char buf[32];
1570                 if (opt->pathname) {
1571                         output_color(opt, gs->name, strlen(gs->name),
1572                                      opt->color_filename);
1573                         output_sep(opt, ':');
1574                 }
1575                 snprintf(buf, sizeof(buf), "%u\n", count);
1576                 opt->output(opt, buf, strlen(buf));
1577                 return 1;
1578         }
1579         return !!last_hit;
1580 }
1581
1582 static void clr_hit_marker(struct grep_expr *x)
1583 {
1584         /* All-hit markers are meaningful only at the very top level
1585          * OR node.
1586          */
1587         while (1) {
1588                 x->hit = 0;
1589                 if (x->node != GREP_NODE_OR)
1590                         return;
1591                 x->u.binary.left->hit = 0;
1592                 x = x->u.binary.right;
1593         }
1594 }
1595
1596 static int chk_hit_marker(struct grep_expr *x)
1597 {
1598         /* Top level nodes have hit markers.  See if they all are hits */
1599         while (1) {
1600                 if (x->node != GREP_NODE_OR)
1601                         return x->hit;
1602                 if (!x->u.binary.left->hit)
1603                         return 0;
1604                 x = x->u.binary.right;
1605         }
1606 }
1607
1608 int grep_source(struct grep_opt *opt, struct grep_source *gs)
1609 {
1610         /*
1611          * we do not have to do the two-pass grep when we do not check
1612          * buffer-wide "all-match".
1613          */
1614         if (!opt->all_match)
1615                 return grep_source_1(opt, gs, 0);
1616
1617         /* Otherwise the toplevel "or" terms hit a bit differently.
1618          * We first clear hit markers from them.
1619          */
1620         clr_hit_marker(opt->pattern_expression);
1621         grep_source_1(opt, gs, 1);
1622
1623         if (!chk_hit_marker(opt->pattern_expression))
1624                 return 0;
1625
1626         return grep_source_1(opt, gs, 0);
1627 }
1628
1629 int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size)
1630 {
1631         struct grep_source gs;
1632         int r;
1633
1634         grep_source_init(&gs, GREP_SOURCE_BUF, NULL, NULL, NULL);
1635         gs.buf = buf;
1636         gs.size = size;
1637
1638         r = grep_source(opt, &gs);
1639
1640         grep_source_clear(&gs);
1641         return r;
1642 }
1643
1644 void grep_source_init(struct grep_source *gs, enum grep_source_type type,
1645                       const char *name, const char *path,
1646                       const void *identifier)
1647 {
1648         gs->type = type;
1649         gs->name = name ? xstrdup(name) : NULL;
1650         gs->path = path ? xstrdup(path) : NULL;
1651         gs->buf = NULL;
1652         gs->size = 0;
1653         gs->driver = NULL;
1654
1655         switch (type) {
1656         case GREP_SOURCE_FILE:
1657                 gs->identifier = xstrdup(identifier);
1658                 break;
1659         case GREP_SOURCE_SHA1:
1660                 gs->identifier = xmalloc(20);
1661                 hashcpy(gs->identifier, identifier);
1662                 break;
1663         case GREP_SOURCE_BUF:
1664                 gs->identifier = NULL;
1665         }
1666 }
1667
1668 void grep_source_clear(struct grep_source *gs)
1669 {
1670         free(gs->name);
1671         gs->name = NULL;
1672         free(gs->path);
1673         gs->path = NULL;
1674         free(gs->identifier);
1675         gs->identifier = NULL;
1676         grep_source_clear_data(gs);
1677 }
1678
1679 void grep_source_clear_data(struct grep_source *gs)
1680 {
1681         switch (gs->type) {
1682         case GREP_SOURCE_FILE:
1683         case GREP_SOURCE_SHA1:
1684                 free(gs->buf);
1685                 gs->buf = NULL;
1686                 gs->size = 0;
1687                 break;
1688         case GREP_SOURCE_BUF:
1689                 /* leave user-provided buf intact */
1690                 break;
1691         }
1692 }
1693
1694 static int grep_source_load_sha1(struct grep_source *gs)
1695 {
1696         enum object_type type;
1697
1698         grep_read_lock();
1699         gs->buf = read_sha1_file(gs->identifier, &type, &gs->size);
1700         grep_read_unlock();
1701
1702         if (!gs->buf)
1703                 return error(_("'%s': unable to read %s"),
1704                              gs->name,
1705                              sha1_to_hex(gs->identifier));
1706         return 0;
1707 }
1708
1709 static int grep_source_load_file(struct grep_source *gs)
1710 {
1711         const char *filename = gs->identifier;
1712         struct stat st;
1713         char *data;
1714         size_t size;
1715         int i;
1716
1717         if (lstat(filename, &st) < 0) {
1718         err_ret:
1719                 if (errno != ENOENT)
1720                         error(_("'%s': %s"), filename, strerror(errno));
1721                 return -1;
1722         }
1723         if (!S_ISREG(st.st_mode))
1724                 return -1;
1725         size = xsize_t(st.st_size);
1726         i = open(filename, O_RDONLY);
1727         if (i < 0)
1728                 goto err_ret;
1729         data = xmalloc(size + 1);
1730         if (st.st_size != read_in_full(i, data, size)) {
1731                 error(_("'%s': short read %s"), filename, strerror(errno));
1732                 close(i);
1733                 free(data);
1734                 return -1;
1735         }
1736         close(i);
1737         data[size] = 0;
1738
1739         gs->buf = data;
1740         gs->size = size;
1741         return 0;
1742 }
1743
1744 static int grep_source_load(struct grep_source *gs)
1745 {
1746         if (gs->buf)
1747                 return 0;
1748
1749         switch (gs->type) {
1750         case GREP_SOURCE_FILE:
1751                 return grep_source_load_file(gs);
1752         case GREP_SOURCE_SHA1:
1753                 return grep_source_load_sha1(gs);
1754         case GREP_SOURCE_BUF:
1755                 return gs->buf ? 0 : -1;
1756         }
1757         die("BUG: invalid grep_source type");
1758 }
1759
1760 void grep_source_load_driver(struct grep_source *gs)
1761 {
1762         if (gs->driver)
1763                 return;
1764
1765         grep_attr_lock();
1766         if (gs->path)
1767                 gs->driver = userdiff_find_by_path(gs->path);
1768         if (!gs->driver)
1769                 gs->driver = userdiff_find_by_name("default");
1770         grep_attr_unlock();
1771 }
1772
1773 static int grep_source_is_binary(struct grep_source *gs)
1774 {
1775         grep_source_load_driver(gs);
1776         if (gs->driver->binary != -1)
1777                 return gs->driver->binary;
1778
1779         if (!grep_source_load(gs))
1780                 return buffer_is_binary(gs->buf, gs->size);
1781
1782         return 0;
1783 }