grep.c

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