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