grep.c

   1 #include "git-compat-util.h"
   2 #include "config.h"
   3 #include "gettext.h"
   4 #include "grep.h"
   5 #include "hex.h"
   6 #include "object-store-ll.h"
   7 #include "pretty.h"
   8 #include "userdiff.h"
   9 #include "xdiff-interface.h"
  10 #include "diff.h"
  11 #include "diffcore.h"
  12 #include "commit.h"
  13 #include "quote.h"
  14 #include "help.h"
  15
  16 static int grep_source_load(struct grep_source *gs);
  17 static int grep_source_is_binary(struct grep_source *gs,
  18                                  struct index_state *istate);
  19
  20 static void std_output(struct grep_opt *opt, const void *buf, size_t size)
  21 {
  22         fwrite(buf, size, 1, stdout);
  23 }
  24
  25 static const char *color_grep_slots[] = {
  26         [GREP_COLOR_CONTEXT]        = "context",
  27         [GREP_COLOR_FILENAME]       = "filename",
  28         [GREP_COLOR_FUNCTION]       = "function",
  29         [GREP_COLOR_LINENO]         = "lineNumber",
  30         [GREP_COLOR_COLUMNNO]       = "column",
  31         [GREP_COLOR_MATCH_CONTEXT]  = "matchContext",
  32         [GREP_COLOR_MATCH_SELECTED] = "matchSelected",
  33         [GREP_COLOR_SELECTED]       = "selected",
  34         [GREP_COLOR_SEP]            = "separator",
  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 define_list_config_array_extra(color_grep_slots, {"match"});
  53
  54 /*
  55  * Read the configuration file once and store it in
  56  * the grep_defaults template.
  57  */
  58 int grep_config(const char *var, const char *value,
  59                 const struct config_context *ctx, void *cb)
  60 {
  61         struct grep_opt *opt = cb;
  62         const char *slot;
  63
  64         if (userdiff_config(var, value) < 0)
  65                 return -1;
  66
  67         if (!strcmp(var, "grep.extendedregexp")) {
  68                 opt->extended_regexp_option = git_config_bool(var, value);
  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         if (!strcmp(var, "grep.column")) {
  82                 opt->columnnum = git_config_bool(var, value);
  83                 return 0;
  84         }
  85
  86         if (!strcmp(var, "grep.fullname")) {
  87                 opt->relative = !git_config_bool(var, value);
  88                 return 0;
  89         }
  90
  91         if (!strcmp(var, "color.grep"))
  92                 opt->color = git_config_colorbool(var, value);
  93         if (!strcmp(var, "color.grep.match")) {
  94                 if (grep_config("color.grep.matchcontext", value, ctx, cb) < 0)
  95                         return -1;
  96                 if (grep_config("color.grep.matchselected", value, ctx, cb) < 0)
  97                         return -1;
  98         } else if (skip_prefix(var, "color.grep.", &slot)) {
  99                 int i = LOOKUP_CONFIG(color_grep_slots, slot);
 100                 char *color;
 101
 102                 if (i < 0)
 103                         return -1;
 104                 color = opt->colors[i];
 105                 if (!value)
 106                         return config_error_nonbool(var);
 107                 return color_parse(value, color);
 108         }
 109         return 0;
 110 }
 111
 112 void grep_init(struct grep_opt *opt, struct repository *repo)
 113 {
 114         struct grep_opt blank = GREP_OPT_INIT;
 115         memcpy(opt, &blank, sizeof(*opt));
 116
 117         opt->repo = repo;
 118         opt->pattern_tail = &opt->pattern_list;
 119         opt->header_tail = &opt->header_list;
 120 }
 121
 122 static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 123                                         const char *origin, int no,
 124                                         enum grep_pat_token t,
 125                                         enum grep_header_field field)
 126 {
 127         struct grep_pat *p = xcalloc(1, sizeof(*p));
 128         p->pattern = xmemdupz(pat, patlen);
 129         p->patternlen = patlen;
 130         p->origin = origin;
 131         p->no = no;
 132         p->token = t;
 133         p->field = field;
 134         return p;
 135 }
 136
 137 static void do_append_grep_pat(struct grep_pat ***tail, struct grep_pat *p)
 138 {
 139         **tail = p;
 140         *tail = &p->next;
 141         p->next = NULL;
 142
 143         switch (p->token) {
 144         case GREP_PATTERN: /* atom */
 145         case GREP_PATTERN_HEAD:
 146         case GREP_PATTERN_BODY:
 147                 for (;;) {
 148                         struct grep_pat *new_pat;
 149                         size_t len = 0;
 150                         char *cp = p->pattern + p->patternlen, *nl = NULL;
 151                         while (++len <= p->patternlen) {
 152                                 if (*(--cp) == '\n') {
 153                                         nl = cp;
 154                                         break;
 155                                 }
 156                         }
 157                         if (!nl)
 158                                 break;
 159                         new_pat = create_grep_pat(nl + 1, len - 1, p->origin,
 160                                                   p->no, p->token, p->field);
 161                         new_pat->next = p->next;
 162                         if (!p->next)
 163                                 *tail = &new_pat->next;
 164                         p->next = new_pat;
 165                         *nl = '\0';
 166                         p->patternlen -= len;
 167                 }
 168                 break;
 169         default:
 170                 break;
 171         }
 172 }
 173
 174 void append_header_grep_pattern(struct grep_opt *opt,
 175                                 enum grep_header_field field, const char *pat)
 176 {
 177         struct grep_pat *p = create_grep_pat(pat, strlen(pat), "header", 0,
 178                                              GREP_PATTERN_HEAD, field);
 179         if (field == GREP_HEADER_REFLOG)
 180                 opt->use_reflog_filter = 1;
 181         do_append_grep_pat(&opt->header_tail, p);
 182 }
 183
 184 void append_grep_pattern(struct grep_opt *opt, const char *pat,
 185                          const char *origin, int no, enum grep_pat_token t)
 186 {
 187         append_grep_pat(opt, pat, strlen(pat), origin, no, t);
 188 }
 189
 190 void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
 191                      const char *origin, int no, enum grep_pat_token t)
 192 {
 193         struct grep_pat *p = create_grep_pat(pat, patlen, origin, no, t, 0);
 194         do_append_grep_pat(&opt->pattern_tail, p);
 195 }
 196
 197 struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
 198 {
 199         struct grep_pat *pat;
 200         struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
 201         *ret = *opt;
 202
 203         ret->pattern_list = NULL;
 204         ret->pattern_tail = &ret->pattern_list;
 205
 206         for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
 207         {
 208                 if(pat->token == GREP_PATTERN_HEAD)
 209                         append_header_grep_pattern(ret, pat->field,
 210                                                    pat->pattern);
 211                 else
 212                         append_grep_pat(ret, pat->pattern, pat->patternlen,
 213                                         pat->origin, pat->no, pat->token);
 214         }
 215
 216         return ret;
 217 }
 218
 219 static NORETURN void compile_regexp_failed(const struct grep_pat *p,
 220                 const char *error)
 221 {
 222         char where[1024];
 223
 224         if (p->no)
 225                 xsnprintf(where, sizeof(where), "In '%s' at %d, ", p->origin, p->no);
 226         else if (p->origin)
 227                 xsnprintf(where, sizeof(where), "%s, ", p->origin);
 228         else
 229                 where[0] = 0;
 230
 231         die("%s'%s': %s", where, p->pattern, error);
 232 }
 233
 234 static int is_fixed(const char *s, size_t len)
 235 {
 236         size_t i;
 237
 238         for (i = 0; i < len; i++) {
 239                 if (is_regex_special(s[i]))
 240                         return 0;
 241         }
 242
 243         return 1;
 244 }
 245
 246 #ifdef USE_LIBPCRE2
 247 #define GREP_PCRE2_DEBUG_MALLOC 0
 248
 249 static void *pcre2_malloc(PCRE2_SIZE size, MAYBE_UNUSED void *memory_data)
 250 {
 251         void *pointer = malloc(size);
 252 #if GREP_PCRE2_DEBUG_MALLOC
 253         static int count = 1;
 254         fprintf(stderr, "PCRE2:%p -> #%02d: alloc(%lu)\n", pointer, count++, size);
 255 #endif
 256         return pointer;
 257 }
 258
 259 static void pcre2_free(void *pointer, MAYBE_UNUSED void *memory_data)
 260 {
 261 #if GREP_PCRE2_DEBUG_MALLOC
 262         static int count = 1;
 263         if (pointer)
 264                 fprintf(stderr, "PCRE2:%p -> #%02d: free()\n", pointer, count++);
 265 #endif
 266         free(pointer);
 267 }
 268
 269 static int pcre2_jit_functional(void)
 270 {
 271         static int jit_working = -1;
 272         pcre2_code *code;
 273         size_t off;
 274         int err;
 275
 276         if (jit_working != -1)
 277                 return jit_working;
 278
 279         /*
 280          * Try to JIT compile a simple pattern to probe if the JIT is
 281          * working in general. It might fail for systems where creating
 282          * memory mappings for runtime code generation is restricted.
 283          */
 284         code = pcre2_compile((PCRE2_SPTR)".", 1, 0, &err, &off, NULL);
 285         if (!code)
 286                 return 0;
 287
 288         jit_working = pcre2_jit_compile(code, PCRE2_JIT_COMPLETE) == 0;
 289         pcre2_code_free(code);
 290
 291         return jit_working;
 292 }
 293
 294 static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
 295 {
 296         int error;
 297         PCRE2_UCHAR errbuf[256];
 298         PCRE2_SIZE erroffset;
 299         int options = PCRE2_MULTILINE;
 300         int jitret;
 301         int patinforet;
 302         size_t jitsizearg;
 303         int literal = !opt->ignore_case && (p->fixed || p->is_fixed);
 304
 305         /*
 306          * Call pcre2_general_context_create() before calling any
 307          * other pcre2_*(). It sets up our malloc()/free() functions
 308          * with which everything else is allocated.
 309          */
 310         p->pcre2_general_context = pcre2_general_context_create(
 311                 pcre2_malloc, pcre2_free, NULL);
 312         if (!p->pcre2_general_context)
 313                 die("Couldn't allocate PCRE2 general context");
 314
 315         if (opt->ignore_case) {
 316                 if (!opt->ignore_locale && has_non_ascii(p->pattern)) {
 317                         p->pcre2_tables = pcre2_maketables(p->pcre2_general_context);
 318                         p->pcre2_compile_context = pcre2_compile_context_create(p->pcre2_general_context);
 319                         pcre2_set_character_tables(p->pcre2_compile_context,
 320                                                         p->pcre2_tables);
 321                 }
 322                 options |= PCRE2_CASELESS;
 323         }
 324         if (!opt->ignore_locale && is_utf8_locale() && !literal)
 325                 options |= (PCRE2_UTF | PCRE2_UCP | PCRE2_MATCH_INVALID_UTF);
 326
 327 #ifndef GIT_PCRE2_VERSION_10_35_OR_HIGHER
 328         /*
 329          * Work around a JIT bug related to invalid Unicode character handling
 330          * fixed in 10.35:
 331          * https://github.com/PCRE2Project/pcre2/commit/c21bd977547d
 332          */
 333         options &= ~PCRE2_UCP;
 334 #endif
 335
 336 #ifndef GIT_PCRE2_VERSION_10_36_OR_HIGHER
 337         /* Work around https://bugs.exim.org/show_bug.cgi?id=2642 fixed in 10.36 */
 338         if (PCRE2_MATCH_INVALID_UTF && options & (PCRE2_UTF | PCRE2_CASELESS))
 339                 options |= PCRE2_NO_START_OPTIMIZE;
 340 #endif
 341
 342         p->pcre2_pattern = pcre2_compile((PCRE2_SPTR)p->pattern,
 343                                          p->patternlen, options, &error, &erroffset,
 344                                          p->pcre2_compile_context);
 345
 346         if (p->pcre2_pattern) {
 347                 p->pcre2_match_data = pcre2_match_data_create_from_pattern(p->pcre2_pattern, p->pcre2_general_context);
 348                 if (!p->pcre2_match_data)
 349                         die("Couldn't allocate PCRE2 match data");
 350         } else {
 351                 pcre2_get_error_message(error, errbuf, sizeof(errbuf));
 352                 compile_regexp_failed(p, (const char *)&errbuf);
 353         }
 354
 355         pcre2_config(PCRE2_CONFIG_JIT, &p->pcre2_jit_on);
 356         if (p->pcre2_jit_on) {
 357                 jitret = pcre2_jit_compile(p->pcre2_pattern, PCRE2_JIT_COMPLETE);
 358                 if (jitret == PCRE2_ERROR_NOMEMORY && !pcre2_jit_functional()) {
 359                         /*
 360                          * Even though pcre2_config(PCRE2_CONFIG_JIT, ...)
 361                          * indicated JIT support, the library might still
 362                          * fail to generate JIT code for various reasons,
 363                          * e.g. when SELinux's 'deny_execmem' or PaX's
 364                          * MPROTECT prevent creating W|X memory mappings.
 365                          *
 366                          * Instead of faling hard, fall back to interpreter
 367                          * mode, just as if the pattern was prefixed with
 368                          * '(*NO_JIT)'.
 369                          */
 370                         p->pcre2_jit_on = 0;
 371                         return;
 372                 } else if (jitret) {
 373                         int need_clip = p->patternlen > 64;
 374                         int clip_len = need_clip ? 64 : p->patternlen;
 375                         die("Couldn't JIT the PCRE2 pattern '%.*s'%s, got '%d'%s",
 376                             clip_len, p->pattern, need_clip ? "..." : "", jitret,
 377                             pcre2_jit_functional()
 378                             ? "\nPerhaps prefix (*NO_JIT) to your pattern?"
 379                             : "");
 380                 }
 381
 382                 /*
 383                  * The pcre2_config(PCRE2_CONFIG_JIT, ...) call just
 384                  * tells us whether the library itself supports JIT,
 385                  * but to see whether we're going to be actually using
 386                  * JIT we need to extract PCRE2_INFO_JITSIZE from the
 387                  * pattern *after* we do pcre2_jit_compile() above.
 388                  *
 389                  * This is because if the pattern contains the
 390                  * (*NO_JIT) verb (see pcre2syntax(3))
 391                  * pcre2_jit_compile() will exit early with 0. If we
 392                  * then proceed to call pcre2_jit_match() further down
 393                  * the line instead of pcre2_match() we'll either
 394                  * segfault (pre PCRE 10.31) or run into a fatal error
 395                  * (post PCRE2 10.31)
 396                  */
 397                 patinforet = pcre2_pattern_info(p->pcre2_pattern, PCRE2_INFO_JITSIZE, &jitsizearg);
 398                 if (patinforet)
 399                         BUG("pcre2_pattern_info() failed: %d", patinforet);
 400                 if (jitsizearg == 0) {
 401                         p->pcre2_jit_on = 0;
 402                         return;
 403                 }
 404         }
 405 }
 406
 407 static int pcre2match(struct grep_pat *p, const char *line, const char *eol,
 408                 regmatch_t *match, int eflags)
 409 {
 410         int ret, flags = 0;
 411         PCRE2_SIZE *ovector;
 412         PCRE2_UCHAR errbuf[256];
 413
 414         if (eflags & REG_NOTBOL)
 415                 flags |= PCRE2_NOTBOL;
 416
 417         if (p->pcre2_jit_on)
 418                 ret = pcre2_jit_match(p->pcre2_pattern, (unsigned char *)line,
 419                                       eol - line, 0, flags, p->pcre2_match_data,
 420                                       NULL);
 421         else
 422                 ret = pcre2_match(p->pcre2_pattern, (unsigned char *)line,
 423                                   eol - line, 0, flags, p->pcre2_match_data,
 424                                   NULL);
 425
 426         if (ret < 0 && ret != PCRE2_ERROR_NOMATCH) {
 427                 pcre2_get_error_message(ret, errbuf, sizeof(errbuf));
 428                 die("%s failed with error code %d: %s",
 429                     (p->pcre2_jit_on ? "pcre2_jit_match" : "pcre2_match"), ret,
 430                     errbuf);
 431         }
 432         if (ret > 0) {
 433                 ovector = pcre2_get_ovector_pointer(p->pcre2_match_data);
 434                 ret = 0;
 435                 match->rm_so = (int)ovector[0];
 436                 match->rm_eo = (int)ovector[1];
 437         }
 438
 439         return ret;
 440 }
 441
 442 static void free_pcre2_pattern(struct grep_pat *p)
 443 {
 444         pcre2_compile_context_free(p->pcre2_compile_context);
 445         pcre2_code_free(p->pcre2_pattern);
 446         pcre2_match_data_free(p->pcre2_match_data);
 447 #ifdef GIT_PCRE2_VERSION_10_34_OR_HIGHER
 448         pcre2_maketables_free(p->pcre2_general_context, p->pcre2_tables);
 449 #else
 450         free((void *)p->pcre2_tables);
 451 #endif
 452         pcre2_general_context_free(p->pcre2_general_context);
 453 }
 454 #else /* !USE_LIBPCRE2 */
 455 static void compile_pcre2_pattern(struct grep_pat *p, const struct grep_opt *opt)
 456 {
 457         die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 458 }
 459
 460 static int pcre2match(struct grep_pat *p, const char *line, const char *eol,
 461                 regmatch_t *match, int eflags)
 462 {
 463         return 1;
 464 }
 465
 466 static void free_pcre2_pattern(struct grep_pat *p)
 467 {
 468 }
 469
 470 static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)
 471 {
 472         struct strbuf sb = STRBUF_INIT;
 473         int err;
 474         int regflags = 0;
 475
 476         basic_regex_quote_buf(&sb, p->pattern);
 477         if (opt->ignore_case)
 478                 regflags |= REG_ICASE;
 479         err = regcomp(&p->regexp, sb.buf, regflags);
 480         strbuf_release(&sb);
 481         if (err) {
 482                 char errbuf[1024];
 483                 regerror(err, &p->regexp, errbuf, sizeof(errbuf));
 484                 compile_regexp_failed(p, errbuf);
 485         }
 486 }
 487 #endif /* !USE_LIBPCRE2 */
 488
 489 static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 490 {
 491         int err;
 492         int regflags = REG_NEWLINE;
 493
 494         if (opt->pattern_type_option == GREP_PATTERN_TYPE_UNSPECIFIED)
 495                 opt->pattern_type_option = (opt->extended_regexp_option
 496                                             ? GREP_PATTERN_TYPE_ERE
 497                                             : GREP_PATTERN_TYPE_BRE);
 498
 499         p->word_regexp = opt->word_regexp;
 500         p->ignore_case = opt->ignore_case;
 501         p->fixed = opt->pattern_type_option == GREP_PATTERN_TYPE_FIXED;
 502
 503         if (opt->pattern_type_option != GREP_PATTERN_TYPE_PCRE &&
 504             memchr(p->pattern, 0, p->patternlen))
 505                 die(_("given pattern contains NULL byte (via -f <file>). This is only supported with -P under PCRE v2"));
 506
 507         p->is_fixed = is_fixed(p->pattern, p->patternlen);
 508 #ifdef USE_LIBPCRE2
 509        if (!p->fixed && !p->is_fixed) {
 510                const char *no_jit = "(*NO_JIT)";
 511                const int no_jit_len = strlen(no_jit);
 512                if (starts_with(p->pattern, no_jit) &&
 513                    is_fixed(p->pattern + no_jit_len,
 514                             p->patternlen - no_jit_len))
 515                        p->is_fixed = 1;
 516        }
 517 #endif
 518         if (p->fixed || p->is_fixed) {
 519 #ifdef USE_LIBPCRE2
 520                 if (p->is_fixed) {
 521                         compile_pcre2_pattern(p, opt);
 522                 } else {
 523                         /*
 524                          * E.g. t7811-grep-open.sh relies on the
 525                          * pattern being restored.
 526                          */
 527                         char *old_pattern = p->pattern;
 528                         size_t old_patternlen = p->patternlen;
 529                         struct strbuf sb = STRBUF_INIT;
 530
 531                         /*
 532                          * There is the PCRE2_LITERAL flag, but it's
 533                          * only in PCRE v2 10.30 and later. Needing to
 534                          * ifdef our way around that and dealing with
 535                          * it + PCRE2_MULTILINE being an error is more
 536                          * complex than just quoting this ourselves.
 537                         */
 538                         strbuf_add(&sb, "\\Q", 2);
 539                         strbuf_add(&sb, p->pattern, p->patternlen);
 540                         strbuf_add(&sb, "\\E", 2);
 541
 542                         p->pattern = sb.buf;
 543                         p->patternlen = sb.len;
 544                         compile_pcre2_pattern(p, opt);
 545                         p->pattern = old_pattern;
 546                         p->patternlen = old_patternlen;
 547                         strbuf_release(&sb);
 548                 }
 549 #else /* !USE_LIBPCRE2 */
 550                 compile_fixed_regexp(p, opt);
 551 #endif /* !USE_LIBPCRE2 */
 552                 return;
 553         }
 554
 555         if (opt->pattern_type_option == GREP_PATTERN_TYPE_PCRE) {
 556                 compile_pcre2_pattern(p, opt);
 557                 return;
 558         }
 559
 560         if (p->ignore_case)
 561                 regflags |= REG_ICASE;
 562         if (opt->pattern_type_option == GREP_PATTERN_TYPE_ERE)
 563                 regflags |= REG_EXTENDED;
 564         err = regcomp(&p->regexp, p->pattern, regflags);
 565         if (err) {
 566                 char errbuf[1024];
 567                 regerror(err, &p->regexp, errbuf, 1024);
 568                 compile_regexp_failed(p, errbuf);
 569         }
 570 }
 571
 572 static struct grep_expr *grep_not_expr(struct grep_expr *expr)
 573 {
 574         struct grep_expr *z = xcalloc(1, sizeof(*z));
 575         z->node = GREP_NODE_NOT;
 576         z->u.unary = expr;
 577         return z;
 578 }
 579
 580 static struct grep_expr *grep_binexp(enum grep_expr_node kind,
 581                                      struct grep_expr *left,
 582                                      struct grep_expr *right)
 583 {
 584         struct grep_expr *z = xcalloc(1, sizeof(*z));
 585         z->node = kind;
 586         z->u.binary.left = left;
 587         z->u.binary.right = right;
 588         return z;
 589 }
 590
 591 static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 592 {
 593         return grep_binexp(GREP_NODE_OR, left, right);
 594 }
 595
 596 static struct grep_expr *grep_and_expr(struct grep_expr *left, struct grep_expr *right)
 597 {
 598         return grep_binexp(GREP_NODE_AND, left, right);
 599 }
 600
 601 static struct grep_expr *compile_pattern_or(struct grep_pat **);
 602 static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 603 {
 604         struct grep_pat *p;
 605         struct grep_expr *x;
 606
 607         p = *list;
 608         if (!p)
 609                 return NULL;
 610         switch (p->token) {
 611         case GREP_PATTERN: /* atom */
 612         case GREP_PATTERN_HEAD:
 613         case GREP_PATTERN_BODY:
 614                 CALLOC_ARRAY(x, 1);
 615                 x->node = GREP_NODE_ATOM;
 616                 x->u.atom = p;
 617                 *list = p->next;
 618                 return x;
 619         case GREP_OPEN_PAREN:
 620                 *list = p->next;
 621                 x = compile_pattern_or(list);
 622                 if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 623                         die("unmatched parenthesis");
 624                 *list = (*list)->next;
 625                 return x;
 626         default:
 627                 return NULL;
 628         }
 629 }
 630
 631 static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 632 {
 633         struct grep_pat *p;
 634         struct grep_expr *x;
 635
 636         p = *list;
 637         if (!p)
 638                 return NULL;
 639         switch (p->token) {
 640         case GREP_NOT:
 641                 if (!p->next)
 642                         die("--not not followed by pattern expression");
 643                 *list = p->next;
 644                 x = compile_pattern_not(list);
 645                 if (!x)
 646                         die("--not followed by non pattern expression");
 647                 return grep_not_expr(x);
 648         default:
 649                 return compile_pattern_atom(list);
 650         }
 651 }
 652
 653 static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 654 {
 655         struct grep_pat *p;
 656         struct grep_expr *x, *y;
 657
 658         x = compile_pattern_not(list);
 659         p = *list;
 660         if (p && p->token == GREP_AND) {
 661                 if (!x)
 662                         die("--and not preceded by pattern expression");
 663                 if (!p->next)
 664                         die("--and not followed by pattern expression");
 665                 *list = p->next;
 666                 y = compile_pattern_and(list);
 667                 if (!y)
 668                         die("--and not followed by pattern expression");
 669                 return grep_and_expr(x, y);
 670         }
 671         return x;
 672 }
 673
 674 static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 675 {
 676         struct grep_pat *p;
 677         struct grep_expr *x, *y;
 678
 679         x = compile_pattern_and(list);
 680         p = *list;
 681         if (x && p && p->token != GREP_CLOSE_PAREN) {
 682                 y = compile_pattern_or(list);
 683                 if (!y)
 684                         die("not a pattern expression %s", p->pattern);
 685                 return grep_or_expr(x, y);
 686         }
 687         return x;
 688 }
 689
 690 static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 691 {
 692         return compile_pattern_or(list);
 693 }
 694
 695 static struct grep_expr *grep_true_expr(void)
 696 {
 697         struct grep_expr *z = xcalloc(1, sizeof(*z));
 698         z->node = GREP_NODE_TRUE;
 699         return z;
 700 }
 701
 702 static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 703 {
 704         struct grep_pat *p;
 705         struct grep_expr *header_expr;
 706         struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 707         enum grep_header_field fld;
 708
 709         if (!opt->header_list)
 710                 return NULL;
 711
 712         for (p = opt->header_list; p; p = p->next) {
 713                 if (p->token != GREP_PATTERN_HEAD)
 714                         BUG("a non-header pattern in grep header list.");
 715                 if (p->field < GREP_HEADER_FIELD_MIN ||
 716                     GREP_HEADER_FIELD_MAX <= p->field)
 717                         BUG("unknown header field %d", p->field);
 718                 compile_regexp(p, opt);
 719         }
 720
 721         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 722                 header_group[fld] = NULL;
 723
 724         for (p = opt->header_list; p; p = p->next) {
 725                 struct grep_expr *h;
 726                 struct grep_pat *pp = p;
 727
 728                 h = compile_pattern_atom(&pp);
 729                 if (!h || pp != p->next)
 730                         BUG("malformed header expr");
 731                 if (!header_group[p->field]) {
 732                         header_group[p->field] = h;
 733                         continue;
 734                 }
 735                 header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 736         }
 737
 738         header_expr = NULL;
 739
 740         for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 741                 if (!header_group[fld])
 742                         continue;
 743                 if (!header_expr)
 744                         header_expr = grep_true_expr();
 745                 header_expr = grep_or_expr(header_group[fld], header_expr);
 746         }
 747         return header_expr;
 748 }
 749
 750 static struct grep_expr *grep_splice_or(struct grep_expr *x, struct grep_expr *y)
 751 {
 752         struct grep_expr *z = x;
 753
 754         while (x) {
 755                 assert(x->node == GREP_NODE_OR);
 756                 if (x->u.binary.right &&
 757                     x->u.binary.right->node == GREP_NODE_TRUE) {
 758                         x->u.binary.right = y;
 759                         break;
 760                 }
 761                 x = x->u.binary.right;
 762         }
 763         return z;
 764 }
 765
 766 void compile_grep_patterns(struct grep_opt *opt)
 767 {
 768         struct grep_pat *p;
 769         struct grep_expr *header_expr = prep_header_patterns(opt);
 770         int extended = 0;
 771
 772         for (p = opt->pattern_list; p; p = p->next) {
 773                 switch (p->token) {
 774                 case GREP_PATTERN: /* atom */
 775                 case GREP_PATTERN_HEAD:
 776                 case GREP_PATTERN_BODY:
 777                         compile_regexp(p, opt);
 778                         break;
 779                 default:
 780                         extended = 1;
 781                         break;
 782                 }
 783         }
 784
 785         if (opt->all_match || opt->no_body_match || header_expr)
 786                 extended = 1;
 787         else if (!extended)
 788                 return;
 789
 790         p = opt->pattern_list;
 791         if (p)
 792                 opt->pattern_expression = compile_pattern_expr(&p);
 793         if (p)
 794                 die("incomplete pattern expression: %s", p->pattern);
 795
 796         if (opt->no_body_match && opt->pattern_expression)
 797                 opt->pattern_expression = grep_not_expr(opt->pattern_expression);
 798
 799         if (!header_expr)
 800                 return;
 801
 802         if (!opt->pattern_expression)
 803                 opt->pattern_expression = header_expr;
 804         else if (opt->all_match)
 805                 opt->pattern_expression = grep_splice_or(header_expr,
 806                                                          opt->pattern_expression);
 807         else
 808                 opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 809                                                        header_expr);
 810         opt->all_match = 1;
 811 }
 812
 813 static void free_pattern_expr(struct grep_expr *x)
 814 {
 815         switch (x->node) {
 816         case GREP_NODE_TRUE:
 817         case GREP_NODE_ATOM:
 818                 break;
 819         case GREP_NODE_NOT:
 820                 free_pattern_expr(x->u.unary);
 821                 break;
 822         case GREP_NODE_AND:
 823         case GREP_NODE_OR:
 824                 free_pattern_expr(x->u.binary.left);
 825                 free_pattern_expr(x->u.binary.right);
 826                 break;
 827         }
 828         free(x);
 829 }
 830
 831 static void free_grep_pat(struct grep_pat *pattern)
 832 {
 833         struct grep_pat *p, *n;
 834
 835         for (p = pattern; p; p = n) {
 836                 n = p->next;
 837                 switch (p->token) {
 838                 case GREP_PATTERN: /* atom */
 839                 case GREP_PATTERN_HEAD:
 840                 case GREP_PATTERN_BODY:
 841                         if (p->pcre2_pattern)
 842                                 free_pcre2_pattern(p);
 843                         else
 844                                 regfree(&p->regexp);
 845                         free(p->pattern);
 846                         break;
 847                 default:
 848                         break;
 849                 }
 850                 free(p);
 851         }
 852 }
 853
 854 void free_grep_patterns(struct grep_opt *opt)
 855 {
 856         free_grep_pat(opt->pattern_list);
 857         free_grep_pat(opt->header_list);
 858
 859         if (opt->pattern_expression)
 860                 free_pattern_expr(opt->pattern_expression);
 861 }
 862
 863 static const char *end_of_line(const char *cp, unsigned long *left)
 864 {
 865         unsigned long l = *left;
 866         while (l && *cp != '\n') {
 867                 l--;
 868                 cp++;
 869         }
 870         *left = l;
 871         return cp;
 872 }
 873
 874 static int word_char(char ch)
 875 {
 876         return isalnum(ch) || ch == '_';
 877 }
 878
 879 static void output_color(struct grep_opt *opt, const void *data, size_t size,
 880                          const char *color)
 881 {
 882         if (want_color(opt->color) && color && color[0]) {
 883                 opt->output(opt, color, strlen(color));
 884                 opt->output(opt, data, size);
 885                 opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 886         } else
 887                 opt->output(opt, data, size);
 888 }
 889
 890 static void output_sep(struct grep_opt *opt, char sign)
 891 {
 892         if (opt->null_following_name)
 893                 opt->output(opt, "\0", 1);
 894         else
 895                 output_color(opt, &sign, 1, opt->colors[GREP_COLOR_SEP]);
 896 }
 897
 898 static void show_name(struct grep_opt *opt, const char *name)
 899 {
 900         output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
 901         opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 902 }
 903
 904 static int patmatch(struct grep_pat *p,
 905                     const char *line, const char *eol,
 906                     regmatch_t *match, int eflags)
 907 {
 908         int hit;
 909
 910         if (p->pcre2_pattern)
 911                 hit = !pcre2match(p, line, eol, match, eflags);
 912         else
 913                 hit = !regexec_buf(&p->regexp, line, eol - line, 1, match,
 914                                    eflags);
 915
 916         return hit;
 917 }
 918
 919 static void strip_timestamp(const char *bol, const char **eol_p)
 920 {
 921         const char *eol = *eol_p;
 922
 923         while (bol < --eol) {
 924                 if (*eol != '>')
 925                         continue;
 926                 *eol_p = ++eol;
 927                 break;
 928         }
 929 }
 930
 931 static struct {
 932         const char *field;
 933         size_t len;
 934 } header_field[] = {
 935         { "author ", 7 },
 936         { "committer ", 10 },
 937         { "reflog ", 7 },
 938 };
 939
 940 static int headerless_match_one_pattern(struct grep_pat *p,
 941                                         const char *bol, const char *eol,
 942                                         enum grep_context ctx,
 943                                         regmatch_t *pmatch, int eflags)
 944 {
 945         int hit = 0;
 946         const char *start = bol;
 947
 948         if ((p->token != GREP_PATTERN) &&
 949             ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 950                 return 0;
 951
 952  again:
 953         hit = patmatch(p, bol, eol, pmatch, eflags);
 954
 955         if (hit && p->word_regexp) {
 956                 if ((pmatch[0].rm_so < 0) ||
 957                     (eol - bol) < pmatch[0].rm_so ||
 958                     (pmatch[0].rm_eo < 0) ||
 959                     (eol - bol) < pmatch[0].rm_eo)
 960                         die("regexp returned nonsense");
 961
 962                 /* Match beginning must be either beginning of the
 963                  * line, or at word boundary (i.e. the last char must
 964                  * not be a word char).  Similarly, match end must be
 965                  * either end of the line, or at word boundary
 966                  * (i.e. the next char must not be a word char).
 967                  */
 968                 if ( ((pmatch[0].rm_so == 0) ||
 969                       !word_char(bol[pmatch[0].rm_so-1])) &&
 970                      ((pmatch[0].rm_eo == (eol-bol)) ||
 971                       !word_char(bol[pmatch[0].rm_eo])) )
 972                         ;
 973                 else
 974                         hit = 0;
 975
 976                 /* Words consist of at least one character. */
 977                 if (pmatch->rm_so == pmatch->rm_eo)
 978                         hit = 0;
 979
 980                 if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 981                         /* There could be more than one match on the
 982                          * line, and the first match might not be
 983                          * strict word match.  But later ones could be!
 984                          * Forward to the next possible start, i.e. the
 985                          * next position following a non-word char.
 986                          */
 987                         bol = pmatch[0].rm_so + bol + 1;
 988                         while (word_char(bol[-1]) && bol < eol)
 989                                 bol++;
 990                         eflags |= REG_NOTBOL;
 991                         if (bol < eol)
 992                                 goto again;
 993                 }
 994         }
 995         if (hit) {
 996                 pmatch[0].rm_so += bol - start;
 997                 pmatch[0].rm_eo += bol - start;
 998         }
 999         return hit;
1000 }
1001
1002 static int match_one_pattern(struct grep_pat *p,
1003                              const char *bol, const char *eol,
1004                              enum grep_context ctx, regmatch_t *pmatch,
1005                              int eflags)
1006 {
1007         const char *field;
1008         size_t len;
1009
1010         if (p->token == GREP_PATTERN_HEAD) {
1011                 assert(p->field < ARRAY_SIZE(header_field));
1012                 field = header_field[p->field].field;
1013                 len = header_field[p->field].len;
1014                 if (strncmp(bol, field, len))
1015                         return 0;
1016                 bol += len;
1017
1018                 switch (p->field) {
1019                 case GREP_HEADER_AUTHOR:
1020                 case GREP_HEADER_COMMITTER:
1021                         strip_timestamp(bol, &eol);
1022                         break;
1023                 default:
1024                         break;
1025                 }
1026         }
1027
1028         return headerless_match_one_pattern(p, bol, eol, ctx, pmatch, eflags);
1029 }
1030
1031
1032 static int match_expr_eval(struct grep_opt *opt, struct grep_expr *x,
1033                            const char *bol, const char *eol,
1034                            enum grep_context ctx, ssize_t *col,
1035                            ssize_t *icol, int collect_hits)
1036 {
1037         int h = 0;
1038
1039         switch (x->node) {
1040         case GREP_NODE_TRUE:
1041                 h = 1;
1042                 break;
1043         case GREP_NODE_ATOM:
1044                 {
1045                         regmatch_t tmp;
1046                         h = match_one_pattern(x->u.atom, bol, eol, ctx,
1047                                               &tmp, 0);
1048                         if (h && (*col < 0 || tmp.rm_so < *col))
1049                                 *col = tmp.rm_so;
1050                 }
1051                 if (x->u.atom->token == GREP_PATTERN_BODY)
1052                         opt->body_hit |= h;
1053                 break;
1054         case GREP_NODE_NOT:
1055                 /*
1056                  * Upon visiting a GREP_NODE_NOT, col and icol become swapped.
1057                  */
1058                 h = !match_expr_eval(opt, x->u.unary, bol, eol, ctx, icol, col,
1059                                      0);
1060                 break;
1061         case GREP_NODE_AND:
1062                 h = match_expr_eval(opt, x->u.binary.left, bol, eol, ctx, col,
1063                                     icol, 0);
1064                 if (h || opt->columnnum) {
1065                         /*
1066                          * Don't short-circuit AND when given --column, since a
1067                          * NOT earlier in the tree may turn this into an OR. In
1068                          * this case, see the below comment.
1069                          */
1070                         h &= match_expr_eval(opt, x->u.binary.right, bol, eol,
1071                                              ctx, col, icol, 0);
1072                 }
1073                 break;
1074         case GREP_NODE_OR:
1075                 if (!(collect_hits || opt->columnnum)) {
1076                         /*
1077                          * Don't short-circuit OR when given --column (or
1078                          * collecting hits) to ensure we don't skip a later
1079                          * child that would produce an earlier match.
1080                          */
1081                         return (match_expr_eval(opt, x->u.binary.left, bol, eol,
1082                                                 ctx, col, icol, 0) ||
1083                                 match_expr_eval(opt, x->u.binary.right, bol,
1084                                                 eol, ctx, col, icol, 0));
1085                 }
1086                 h = match_expr_eval(opt, x->u.binary.left, bol, eol, ctx, col,
1087                                     icol, 0);
1088                 if (collect_hits)
1089                         x->u.binary.left->hit |= h;
1090                 h |= match_expr_eval(opt, x->u.binary.right, bol, eol, ctx, col,
1091                                      icol, collect_hits);
1092                 break;
1093         default:
1094                 die("Unexpected node type (internal error) %d", x->node);
1095         }
1096         if (collect_hits)
1097                 x->hit |= h;
1098         return h;
1099 }
1100
1101 static int match_expr(struct grep_opt *opt,
1102                       const char *bol, const char *eol,
1103                       enum grep_context ctx, ssize_t *col,
1104                       ssize_t *icol, int collect_hits)
1105 {
1106         struct grep_expr *x = opt->pattern_expression;
1107         return match_expr_eval(opt, x, bol, eol, ctx, col, icol, collect_hits);
1108 }
1109
1110 static int match_line(struct grep_opt *opt,
1111                       const char *bol, const char *eol,
1112                       ssize_t *col, ssize_t *icol,
1113                       enum grep_context ctx, int collect_hits)
1114 {
1115         struct grep_pat *p;
1116         int hit = 0;
1117
1118         if (opt->pattern_expression)
1119                 return match_expr(opt, bol, eol, ctx, col, icol,
1120                                   collect_hits);
1121
1122         /* we do not call with collect_hits without being extended */
1123         for (p = opt->pattern_list; p; p = p->next) {
1124                 regmatch_t tmp;
1125                 if (match_one_pattern(p, bol, eol, ctx, &tmp, 0)) {
1126                         hit |= 1;
1127                         if (!opt->columnnum) {
1128                                 /*
1129                                  * Without --column, any single match on a line
1130                                  * is enough to know that it needs to be
1131                                  * printed. With --column, scan _all_ patterns
1132                                  * to find the earliest.
1133                                  */
1134                                 break;
1135                         }
1136                         if (*col < 0 || tmp.rm_so < *col)
1137                                 *col = tmp.rm_so;
1138                 }
1139         }
1140         return hit;
1141 }
1142
1143 static int match_next_pattern(struct grep_pat *p,
1144                               const char *bol, const char *eol,
1145                               enum grep_context ctx,
1146                               regmatch_t *pmatch, int eflags)
1147 {
1148         regmatch_t match;
1149
1150         if (!headerless_match_one_pattern(p, bol, eol, ctx, &match, eflags))
1151                 return 0;
1152         if (match.rm_so < 0 || match.rm_eo < 0)
1153                 return 0;
1154         if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
1155                 if (match.rm_so > pmatch->rm_so)
1156                         return 1;
1157                 if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
1158                         return 1;
1159         }
1160         pmatch->rm_so = match.rm_so;
1161         pmatch->rm_eo = match.rm_eo;
1162         return 1;
1163 }
1164
1165 int grep_next_match(struct grep_opt *opt,
1166                     const char *bol, const char *eol,
1167                     enum grep_context ctx, regmatch_t *pmatch,
1168                     enum grep_header_field field, int eflags)
1169 {
1170         struct grep_pat *p;
1171         int hit = 0;
1172
1173         pmatch->rm_so = pmatch->rm_eo = -1;
1174         if (bol < eol) {
1175                 for (p = ((ctx == GREP_CONTEXT_HEAD)
1176                            ? opt->header_list : opt->pattern_list);
1177                           p; p = p->next) {
1178                         switch (p->token) {
1179                         case GREP_PATTERN_HEAD:
1180                                 if ((field != GREP_HEADER_FIELD_MAX) &&
1181                                     (p->field != field))
1182                                         continue;
1183                                 /* fall thru */
1184                         case GREP_PATTERN: /* atom */
1185                         case GREP_PATTERN_BODY:
1186                                 hit |= match_next_pattern(p, bol, eol, ctx,
1187                                                           pmatch, eflags);
1188                                 break;
1189                         default:
1190                                 break;
1191                         }
1192                 }
1193         }
1194         return hit;
1195 }
1196
1197 static void show_line_header(struct grep_opt *opt, const char *name,
1198                              unsigned lno, ssize_t cno, char sign)
1199 {
1200         if (opt->heading && opt->last_shown == 0) {
1201                 output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
1202                 opt->output(opt, "\n", 1);
1203         }
1204         opt->last_shown = lno;
1205
1206         if (!opt->heading && opt->pathname) {
1207                 output_color(opt, name, strlen(name), opt->colors[GREP_COLOR_FILENAME]);
1208                 output_sep(opt, sign);
1209         }
1210         if (opt->linenum) {
1211                 char buf[32];
1212                 xsnprintf(buf, sizeof(buf), "%d", lno);
1213                 output_color(opt, buf, strlen(buf), opt->colors[GREP_COLOR_LINENO]);
1214                 output_sep(opt, sign);
1215         }
1216         /*
1217          * Treat 'cno' as the 1-indexed offset from the start of a non-context
1218          * line to its first match. Otherwise, 'cno' is 0 indicating that we are
1219          * being called with a context line.
1220          */
1221         if (opt->columnnum && cno) {
1222                 char buf[32];
1223                 xsnprintf(buf, sizeof(buf), "%"PRIuMAX, (uintmax_t)cno);
1224                 output_color(opt, buf, strlen(buf), opt->colors[GREP_COLOR_COLUMNNO]);
1225                 output_sep(opt, sign);
1226         }
1227 }
1228
1229 static void show_line(struct grep_opt *opt,
1230                       const char *bol, const char *eol,
1231                       const char *name, unsigned lno, ssize_t cno, char sign)
1232 {
1233         int rest = eol - bol;
1234         const char *match_color = NULL;
1235         const char *line_color = NULL;
1236
1237         if (opt->file_break && opt->last_shown == 0) {
1238                 if (opt->show_hunk_mark)
1239                         opt->output(opt, "\n", 1);
1240         } else if (opt->pre_context || opt->post_context || opt->funcbody) {
1241                 if (opt->last_shown == 0) {
1242                         if (opt->show_hunk_mark) {
1243                                 output_color(opt, "--", 2, opt->colors[GREP_COLOR_SEP]);
1244                                 opt->output(opt, "\n", 1);
1245                         }
1246                 } else if (lno > opt->last_shown + 1) {
1247                         output_color(opt, "--", 2, opt->colors[GREP_COLOR_SEP]);
1248                         opt->output(opt, "\n", 1);
1249                 }
1250         }
1251         if (!opt->only_matching) {
1252                 /*
1253                  * In case the line we're being called with contains more than
1254                  * one match, leave printing each header to the loop below.
1255                  */
1256                 show_line_header(opt, name, lno, cno, sign);
1257         }
1258         if (opt->color || opt->only_matching) {
1259                 regmatch_t match;
1260                 enum grep_context ctx = GREP_CONTEXT_BODY;
1261                 int eflags = 0;
1262
1263                 if (opt->color) {
1264                         if (sign == ':')
1265                                 match_color = opt->colors[GREP_COLOR_MATCH_SELECTED];
1266                         else
1267                                 match_color = opt->colors[GREP_COLOR_MATCH_CONTEXT];
1268                         if (sign == ':')
1269                                 line_color = opt->colors[GREP_COLOR_SELECTED];
1270                         else if (sign == '-')
1271                                 line_color = opt->colors[GREP_COLOR_CONTEXT];
1272                         else if (sign == '=')
1273                                 line_color = opt->colors[GREP_COLOR_FUNCTION];
1274                 }
1275                 while (grep_next_match(opt, bol, eol, ctx, &match,
1276                                        GREP_HEADER_FIELD_MAX, eflags)) {
1277                         if (match.rm_so == match.rm_eo)
1278                                 break;
1279
1280                         if (opt->only_matching)
1281                                 show_line_header(opt, name, lno, cno, sign);
1282                         else
1283                                 output_color(opt, bol, match.rm_so, line_color);
1284                         output_color(opt, bol + match.rm_so,
1285                                      match.rm_eo - match.rm_so, match_color);
1286                         if (opt->only_matching)
1287                                 opt->output(opt, "\n", 1);
1288                         bol += match.rm_eo;
1289                         cno += match.rm_eo;
1290                         rest -= match.rm_eo;
1291                         eflags = REG_NOTBOL;
1292                 }
1293         }
1294         if (!opt->only_matching) {
1295                 output_color(opt, bol, rest, line_color);
1296                 opt->output(opt, "\n", 1);
1297         }
1298 }
1299
1300 int grep_use_locks;
1301
1302 /*
1303  * This lock protects access to the gitattributes machinery, which is
1304  * not thread-safe.
1305  */
1306 pthread_mutex_t grep_attr_mutex;
1307
1308 static inline void grep_attr_lock(void)
1309 {
1310         if (grep_use_locks)
1311                 pthread_mutex_lock(&grep_attr_mutex);
1312 }
1313
1314 static inline void grep_attr_unlock(void)
1315 {
1316         if (grep_use_locks)
1317                 pthread_mutex_unlock(&grep_attr_mutex);
1318 }
1319
1320 static int match_funcname(struct grep_opt *opt, struct grep_source *gs,
1321                           const char *bol, const char *eol)
1322 {
1323         xdemitconf_t *xecfg = opt->priv;
1324         if (xecfg && !xecfg->find_func) {
1325                 grep_source_load_driver(gs, opt->repo->index);
1326                 if (gs->driver->funcname.pattern) {
1327                         const struct userdiff_funcname *pe = &gs->driver->funcname;
1328                         xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
1329                 } else {
1330                         xecfg = opt->priv = NULL;
1331                 }
1332         }
1333
1334         if (xecfg) {
1335                 char buf[1];
1336                 return xecfg->find_func(bol, eol - bol, buf, 1,
1337                                         xecfg->find_func_priv) >= 0;
1338         }
1339
1340         if (bol == eol)
1341                 return 0;
1342         if (isalpha(*bol) || *bol == '_' || *bol == '$')
1343                 return 1;
1344         return 0;
1345 }
1346
1347 static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
1348                                const char *bol, unsigned lno)
1349 {
1350         while (bol > gs->buf) {
1351                 const char *eol = --bol;
1352
1353                 while (bol > gs->buf && bol[-1] != '\n')
1354                         bol--;
1355                 lno--;
1356
1357                 if (lno <= opt->last_shown)
1358                         break;
1359
1360                 if (match_funcname(opt, gs, bol, eol)) {
1361                         show_line(opt, bol, eol, gs->name, lno, 0, '=');
1362                         break;
1363                 }
1364         }
1365 }
1366
1367 static int is_empty_line(const char *bol, const char *eol);
1368
1369 static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
1370                              const char *bol, const char *end, unsigned lno)
1371 {
1372         unsigned cur = lno, from = 1, funcname_lno = 0, orig_from;
1373         int funcname_needed = !!opt->funcname, comment_needed = 0;
1374
1375         if (opt->pre_context < lno)
1376                 from = lno - opt->pre_context;
1377         if (from <= opt->last_shown)
1378                 from = opt->last_shown + 1;
1379         orig_from = from;
1380         if (opt->funcbody) {
1381                 if (match_funcname(opt, gs, bol, end))
1382                         comment_needed = 1;
1383                 else
1384                         funcname_needed = 1;
1385                 from = opt->last_shown + 1;
1386         }
1387
1388         /* Rewind. */
1389         while (bol > gs->buf && cur > from) {
1390                 const char *next_bol = bol;
1391                 const char *eol = --bol;
1392
1393                 while (bol > gs->buf && bol[-1] != '\n')
1394                         bol--;
1395                 cur--;
1396                 if (comment_needed && (is_empty_line(bol, eol) ||
1397                                        match_funcname(opt, gs, bol, eol))) {
1398                         comment_needed = 0;
1399                         from = orig_from;
1400                         if (cur < from) {
1401                                 cur++;
1402                                 bol = next_bol;
1403                                 break;
1404                         }
1405                 }
1406                 if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
1407                         funcname_lno = cur;
1408                         funcname_needed = 0;
1409                         if (opt->funcbody)
1410                                 comment_needed = 1;
1411                         else
1412                                 from = orig_from;
1413                 }
1414         }
1415
1416         /* We need to look even further back to find a function signature. */
1417         if (opt->funcname && funcname_needed)
1418                 show_funcname_line(opt, gs, bol, cur);
1419
1420         /* Back forward. */
1421         while (cur < lno) {
1422                 const char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
1423
1424                 while (*eol != '\n')
1425                         eol++;
1426                 show_line(opt, bol, eol, gs->name, cur, 0, sign);
1427                 bol = eol + 1;
1428                 cur++;
1429         }
1430 }
1431
1432 static int should_lookahead(struct grep_opt *opt)
1433 {
1434         struct grep_pat *p;
1435
1436         if (opt->pattern_expression)
1437                 return 0; /* punt for too complex stuff */
1438         if (opt->invert)
1439                 return 0;
1440         for (p = opt->pattern_list; p; p = p->next) {
1441                 if (p->token != GREP_PATTERN)
1442                         return 0; /* punt for "header only" and stuff */
1443         }
1444         return 1;
1445 }
1446
1447 static int look_ahead(struct grep_opt *opt,
1448                       unsigned long *left_p,
1449                       unsigned *lno_p,
1450                       const char **bol_p)
1451 {
1452         unsigned lno = *lno_p;
1453         const char *bol = *bol_p;
1454         struct grep_pat *p;
1455         const char *sp, *last_bol;
1456         regoff_t earliest = -1;
1457
1458         for (p = opt->pattern_list; p; p = p->next) {
1459                 int hit;
1460                 regmatch_t m;
1461
1462                 hit = patmatch(p, bol, bol + *left_p, &m, 0);
1463                 if (!hit || m.rm_so < 0 || m.rm_eo < 0)
1464                         continue;
1465                 if (earliest < 0 || m.rm_so < earliest)
1466                         earliest = m.rm_so;
1467         }
1468
1469         if (earliest < 0) {
1470                 *bol_p = bol + *left_p;
1471                 *left_p = 0;
1472                 return 1;
1473         }
1474         for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
1475                 ; /* find the beginning of the line */
1476         last_bol = sp;
1477
1478         for (sp = bol; sp < last_bol; sp++) {
1479                 if (*sp == '\n')
1480                         lno++;
1481         }
1482         *left_p -= last_bol - bol;
1483         *bol_p = last_bol;
1484         *lno_p = lno;
1485         return 0;
1486 }
1487
1488 static int fill_textconv_grep(struct repository *r,
1489                               struct userdiff_driver *driver,
1490                               struct grep_source *gs)
1491 {
1492         struct diff_filespec *df;
1493         char *buf;
1494         size_t size;
1495
1496         if (!driver || !driver->textconv)
1497                 return grep_source_load(gs);
1498
1499         /*
1500          * The textconv interface is intimately tied to diff_filespecs, so we
1501          * have to pretend to be one. If we could unify the grep_source
1502          * and diff_filespec structs, this mess could just go away.
1503          */
1504         df = alloc_filespec(gs->path);
1505         switch (gs->type) {
1506         case GREP_SOURCE_OID:
1507                 fill_filespec(df, gs->identifier, 1, 0100644);
1508                 break;
1509         case GREP_SOURCE_FILE:
1510                 fill_filespec(df, null_oid(), 0, 0100644);
1511                 break;
1512         default:
1513                 BUG("attempt to textconv something without a path?");
1514         }
1515
1516         /*
1517          * fill_textconv is not remotely thread-safe; it modifies the global
1518          * diff tempfile structure, writes to the_repo's odb and might
1519          * internally call thread-unsafe functions such as the
1520          * prepare_packed_git() lazy-initializator. Because of the last two, we
1521          * must ensure mutual exclusion between this call and the object reading
1522          * API, thus we use obj_read_lock() here.
1523          *
1524          * TODO: allowing text conversion to run in parallel with object
1525          * reading operations might increase performance in the multithreaded
1526          * non-worktreee git-grep with --textconv.
1527          */
1528         obj_read_lock();
1529         size = fill_textconv(r, driver, df, &buf);
1530         obj_read_unlock();
1531         free_filespec(df);
1532
1533         /*
1534          * The normal fill_textconv usage by the diff machinery would just keep
1535          * the textconv'd buf separate from the diff_filespec. But much of the
1536          * grep code passes around a grep_source and assumes that its "buf"
1537          * pointer is the beginning of the thing we are searching. So let's
1538          * install our textconv'd version into the grep_source, taking care not
1539          * to leak any existing buffer.
1540          */
1541         grep_source_clear_data(gs);
1542         gs->buf = buf;
1543         gs->size = size;
1544
1545         return 0;
1546 }
1547
1548 static int is_empty_line(const char *bol, const char *eol)
1549 {
1550         while (bol < eol && isspace(*bol))
1551                 bol++;
1552         return bol == eol;
1553 }
1554
1555 static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int collect_hits)
1556 {
1557         const char *bol;
1558         const char *peek_bol = NULL;
1559         unsigned long left;
1560         unsigned lno = 1;
1561         unsigned last_hit = 0;
1562         int binary_match_only = 0;
1563         unsigned count = 0;
1564         int try_lookahead = 0;
1565         int show_function = 0;
1566         struct userdiff_driver *textconv = NULL;
1567         enum grep_context ctx = GREP_CONTEXT_HEAD;
1568         xdemitconf_t xecfg;
1569
1570         if (!opt->status_only && gs->name == NULL)
1571                 BUG("grep call which could print a name requires "
1572                     "grep_source.name be non-NULL");
1573
1574         if (!opt->output)
1575                 opt->output = std_output;
1576
1577         if (opt->pre_context || opt->post_context || opt->file_break ||
1578             opt->funcbody) {
1579                 /* Show hunk marks, except for the first file. */
1580                 if (opt->last_shown)
1581                         opt->show_hunk_mark = 1;
1582                 /*
1583                  * If we're using threads then we can't easily identify
1584                  * the first file.  Always put hunk marks in that case
1585                  * and skip the very first one later in work_done().
1586                  */
1587                 if (opt->output != std_output)
1588                         opt->show_hunk_mark = 1;
1589         }
1590         opt->last_shown = 0;
1591
1592         if (opt->allow_textconv) {
1593                 grep_source_load_driver(gs, opt->repo->index);
1594                 /*
1595                  * We might set up the shared textconv cache data here, which
1596                  * is not thread-safe. Also, get_oid_with_context() and
1597                  * parse_object() might be internally called. As they are not
1598                  * currently thread-safe and might be racy with object reading,
1599                  * obj_read_lock() must be called.
1600                  */
1601                 grep_attr_lock();
1602                 obj_read_lock();
1603                 textconv = userdiff_get_textconv(opt->repo, gs->driver);
1604                 obj_read_unlock();
1605                 grep_attr_unlock();
1606         }
1607
1608         /*
1609          * We know the result of a textconv is text, so we only have to care
1610          * about binary handling if we are not using it.
1611          */
1612         if (!textconv) {
1613                 switch (opt->binary) {
1614                 case GREP_BINARY_DEFAULT:
1615                         if (grep_source_is_binary(gs, opt->repo->index))
1616                                 binary_match_only = 1;
1617                         break;
1618                 case GREP_BINARY_NOMATCH:
1619                         if (grep_source_is_binary(gs, opt->repo->index))
1620                                 return 0; /* Assume unmatch */
1621                         break;
1622                 case GREP_BINARY_TEXT:
1623                         break;
1624                 default:
1625                         BUG("unknown binary handling mode");
1626                 }
1627         }
1628
1629         memset(&xecfg, 0, sizeof(xecfg));
1630         opt->priv = &xecfg;
1631
1632         try_lookahead = should_lookahead(opt);
1633
1634         if (fill_textconv_grep(opt->repo, textconv, gs) < 0)
1635                 return 0;
1636
1637         bol = gs->buf;
1638         left = gs->size;
1639         while (left) {
1640                 const char *eol;
1641                 int hit;
1642                 ssize_t cno;
1643                 ssize_t col = -1, icol = -1;
1644
1645                 /*
1646                  * look_ahead() skips quickly to the line that possibly
1647                  * has the next hit; don't call it if we need to do
1648                  * something more than just skipping the current line
1649                  * in response to an unmatch for the current line.  E.g.
1650                  * inside a post-context window, we will show the current
1651                  * line as a context around the previous hit when it
1652                  * doesn't hit.
1653                  */
1654                 if (try_lookahead
1655                     && !(last_hit
1656                          && (show_function ||
1657                              lno <= last_hit + opt->post_context))
1658                     && look_ahead(opt, &left, &lno, &bol))
1659                         break;
1660                 eol = end_of_line(bol, &left);
1661
1662                 if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1663                         ctx = GREP_CONTEXT_BODY;
1664
1665                 hit = match_line(opt, bol, eol, &col, &icol, ctx, collect_hits);
1666
1667                 if (collect_hits)
1668                         goto next_line;
1669
1670                 /* "grep -v -e foo -e bla" should list lines
1671                  * that do not have either, so inversion should
1672                  * be done outside.
1673                  */
1674                 if (opt->invert)
1675                         hit = !hit;
1676                 if (opt->unmatch_name_only) {
1677                         if (hit)
1678                                 return 0;
1679                         goto next_line;
1680                 }
1681                 if (hit && (opt->max_count < 0 || count < opt->max_count)) {
1682                         count++;
1683                         if (opt->status_only)
1684                                 return 1;
1685                         if (opt->name_only) {
1686                                 show_name(opt, gs->name);
1687                                 return 1;
1688                         }
1689                         if (opt->count)
1690                                 goto next_line;
1691                         if (binary_match_only) {
1692                                 opt->output(opt, "Binary file ", 12);
1693                                 output_color(opt, gs->name, strlen(gs->name),
1694                                              opt->colors[GREP_COLOR_FILENAME]);
1695                                 opt->output(opt, " matches\n", 9);
1696                                 return 1;
1697                         }
1698                         /* Hit at this line.  If we haven't shown the
1699                          * pre-context lines, we would need to show them.
1700                          */
1701                         if (opt->pre_context || opt->funcbody)
1702                                 show_pre_context(opt, gs, bol, eol, lno);
1703                         else if (opt->funcname)
1704                                 show_funcname_line(opt, gs, bol, lno);
1705                         cno = opt->invert ? icol : col;
1706                         if (cno < 0) {
1707                                 /*
1708                                  * A negative cno indicates that there was no
1709                                  * match on the line. We are thus inverted and
1710                                  * being asked to show all lines that _don't_
1711                                  * match a given expression. Therefore, set cno
1712                                  * to 0 to suggest the whole line matches.
1713                                  */
1714                                 cno = 0;
1715                         }
1716                         show_line(opt, bol, eol, gs->name, lno, cno + 1, ':');
1717                         last_hit = lno;
1718                         if (opt->funcbody)
1719                                 show_function = 1;
1720                         goto next_line;
1721                 }
1722                 if (show_function && (!peek_bol || peek_bol < bol)) {
1723                         unsigned long peek_left = left;
1724                         const char *peek_eol = eol;
1725
1726                         /*
1727                          * Trailing empty lines are not interesting.
1728                          * Peek past them to see if they belong to the
1729                          * body of the current function.
1730                          */
1731                         peek_bol = bol;
1732                         while (is_empty_line(peek_bol, peek_eol)) {
1733                                 peek_bol = peek_eol + 1;
1734                                 peek_eol = end_of_line(peek_bol, &peek_left);
1735                         }
1736
1737                         if (match_funcname(opt, gs, peek_bol, peek_eol))
1738                                 show_function = 0;
1739                 }
1740                 if (show_function ||
1741                     (last_hit && lno <= last_hit + opt->post_context)) {
1742                         /* If the last hit is within the post context,
1743                          * we need to show this line.
1744                          */
1745                         show_line(opt, bol, eol, gs->name, lno, col + 1, '-');
1746                 }
1747
1748         next_line:
1749                 bol = eol + 1;
1750                 if (!left)
1751                         break;
1752                 left--;
1753                 lno++;
1754         }
1755
1756         if (collect_hits)
1757                 return 0;
1758
1759         if (opt->status_only)
1760                 return opt->unmatch_name_only;
1761         if (opt->unmatch_name_only) {
1762                 /* We did not see any hit, so we want to show this */
1763                 show_name(opt, gs->name);
1764                 return 1;
1765         }
1766
1767         xdiff_clear_find_func(&xecfg);
1768         opt->priv = NULL;
1769
1770         /* NEEDSWORK:
1771          * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1772          * which feels mostly useless but sometimes useful.  Maybe
1773          * make it another option?  For now suppress them.
1774          */
1775         if (opt->count && count) {
1776                 char buf[32];
1777                 if (opt->pathname) {
1778                         output_color(opt, gs->name, strlen(gs->name),
1779                                      opt->colors[GREP_COLOR_FILENAME]);
1780                         output_sep(opt, ':');
1781                 }
1782                 xsnprintf(buf, sizeof(buf), "%u\n", count);
1783                 opt->output(opt, buf, strlen(buf));
1784                 return 1;
1785         }
1786         return !!last_hit;
1787 }
1788
1789 static void clr_hit_marker(struct grep_expr *x)
1790 {
1791         /* All-hit markers are meaningful only at the very top level
1792          * OR node.
1793          */
1794         while (1) {
1795                 x->hit = 0;
1796                 if (x->node != GREP_NODE_OR)
1797                         return;
1798                 x->u.binary.left->hit = 0;
1799                 x = x->u.binary.right;
1800         }
1801 }
1802
1803 static int chk_hit_marker(struct grep_expr *x)
1804 {
1805         /* Top level nodes have hit markers.  See if they all are hits */
1806         while (1) {
1807                 if (x->node != GREP_NODE_OR)
1808                         return x->hit;
1809                 if (!x->u.binary.left->hit)
1810                         return 0;
1811                 x = x->u.binary.right;
1812         }
1813 }
1814
1815 int grep_source(struct grep_opt *opt, struct grep_source *gs)
1816 {
1817         /*
1818          * we do not have to do the two-pass grep when we do not check
1819          * buffer-wide "all-match".
1820          */
1821         if (!opt->all_match && !opt->no_body_match)
1822                 return grep_source_1(opt, gs, 0);
1823
1824         /* Otherwise the toplevel "or" terms hit a bit differently.
1825          * We first clear hit markers from them.
1826          */
1827         clr_hit_marker(opt->pattern_expression);
1828         opt->body_hit = 0;
1829         grep_source_1(opt, gs, 1);
1830
1831         if (opt->all_match && !chk_hit_marker(opt->pattern_expression))
1832                 return 0;
1833         if (opt->no_body_match && opt->body_hit)
1834                 return 0;
1835
1836         return grep_source_1(opt, gs, 0);
1837 }
1838
1839 static void grep_source_init_buf(struct grep_source *gs,
1840                                  const char *buf,
1841                                  unsigned long size)
1842 {
1843         gs->type = GREP_SOURCE_BUF;
1844         gs->name = NULL;
1845         gs->path = NULL;
1846         gs->buf = buf;
1847         gs->size = size;
1848         gs->driver = NULL;
1849         gs->identifier = NULL;
1850 }
1851
1852 int grep_buffer(struct grep_opt *opt, const char *buf, unsigned long size)
1853 {
1854         struct grep_source gs;
1855         int r;
1856
1857         grep_source_init_buf(&gs, buf, size);
1858
1859         r = grep_source(opt, &gs);
1860
1861         grep_source_clear(&gs);
1862         return r;
1863 }
1864
1865 void grep_source_init_file(struct grep_source *gs, const char *name,
1866                            const char *path)
1867 {
1868         gs->type = GREP_SOURCE_FILE;
1869         gs->name = xstrdup_or_null(name);
1870         gs->path = xstrdup_or_null(path);
1871         gs->buf = NULL;
1872         gs->size = 0;
1873         gs->driver = NULL;
1874         gs->identifier = xstrdup(path);
1875 }
1876
1877 void grep_source_init_oid(struct grep_source *gs, const char *name,
1878                           const char *path, const struct object_id *oid,
1879                           struct repository *repo)
1880 {
1881         gs->type = GREP_SOURCE_OID;
1882         gs->name = xstrdup_or_null(name);
1883         gs->path = xstrdup_or_null(path);
1884         gs->buf = NULL;
1885         gs->size = 0;
1886         gs->driver = NULL;
1887         gs->identifier = oiddup(oid);
1888         gs->repo = repo;
1889 }
1890
1891 void grep_source_clear(struct grep_source *gs)
1892 {
1893         FREE_AND_NULL(gs->name);
1894         FREE_AND_NULL(gs->path);
1895         FREE_AND_NULL(gs->identifier);
1896         grep_source_clear_data(gs);
1897 }
1898
1899 void grep_source_clear_data(struct grep_source *gs)
1900 {
1901         switch (gs->type) {
1902         case GREP_SOURCE_FILE:
1903         case GREP_SOURCE_OID:
1904                 /* these types own the buffer */
1905                 free((char *)gs->buf);
1906                 gs->buf = NULL;
1907                 gs->size = 0;
1908                 break;
1909         case GREP_SOURCE_BUF:
1910                 /* leave user-provided buf intact */
1911                 break;
1912         }
1913 }
1914
1915 static int grep_source_load_oid(struct grep_source *gs)
1916 {
1917         enum object_type type;
1918
1919         gs->buf = repo_read_object_file(gs->repo, gs->identifier, &type,
1920                                         &gs->size);
1921         if (!gs->buf)
1922                 return error(_("'%s': unable to read %s"),
1923                              gs->name,
1924                              oid_to_hex(gs->identifier));
1925         return 0;
1926 }
1927
1928 static int grep_source_load_file(struct grep_source *gs)
1929 {
1930         const char *filename = gs->identifier;
1931         struct stat st;
1932         char *data;
1933         size_t size;
1934         int i;
1935
1936         if (lstat(filename, &st) < 0) {
1937         err_ret:
1938                 if (errno != ENOENT)
1939                         error_errno(_("failed to stat '%s'"), filename);
1940                 return -1;
1941         }
1942         if (!S_ISREG(st.st_mode))
1943                 return -1;
1944         size = xsize_t(st.st_size);
1945         i = open(filename, O_RDONLY);
1946         if (i < 0)
1947                 goto err_ret;
1948         data = xmallocz(size);
1949         if (st.st_size != read_in_full(i, data, size)) {
1950                 error_errno(_("'%s': short read"), filename);
1951                 close(i);
1952                 free(data);
1953                 return -1;
1954         }
1955         close(i);
1956
1957         gs->buf = data;
1958         gs->size = size;
1959         return 0;
1960 }
1961
1962 static int grep_source_load(struct grep_source *gs)
1963 {
1964         if (gs->buf)
1965                 return 0;
1966
1967         switch (gs->type) {
1968         case GREP_SOURCE_FILE:
1969                 return grep_source_load_file(gs);
1970         case GREP_SOURCE_OID:
1971                 return grep_source_load_oid(gs);
1972         case GREP_SOURCE_BUF:
1973                 return gs->buf ? 0 : -1;
1974         }
1975         BUG("invalid grep_source type to load");
1976 }
1977
1978 void grep_source_load_driver(struct grep_source *gs,
1979                              struct index_state *istate)
1980 {
1981         if (gs->driver)
1982                 return;
1983
1984         grep_attr_lock();
1985         if (gs->path)
1986                 gs->driver = userdiff_find_by_path(istate, gs->path);
1987         if (!gs->driver)
1988                 gs->driver = userdiff_find_by_name("default");
1989         grep_attr_unlock();
1990 }
1991
1992 static int grep_source_is_binary(struct grep_source *gs,
1993                                  struct index_state *istate)
1994 {
1995         grep_source_load_driver(gs, istate);
1996         if (gs->driver->binary != -1)
1997                 return gs->driver->binary;
1998
1999         if (!grep_source_load(gs))
2000                 return buffer_is_binary(gs->buf, gs->size);
2001
2002         return 0;
2003 }