bf6c2494fd45039a0d2fad00ebf8be7dde75cc67
   1#include "cache.h"
   2#include "grep.h"
   3#include "userdiff.h"
   4#include "xdiff-interface.h"
   5#include "diff.h"
   6#include "diffcore.h"
   7#include "commit.h"
   8#include "quote.h"
   9
  10static int grep_source_load(struct grep_source *gs);
  11static int grep_source_is_binary(struct grep_source *gs);
  12
  13static struct grep_opt grep_defaults;
  14
  15static void std_output(struct grep_opt *opt, const void *buf, size_t size)
  16{
  17        fwrite(buf, size, 1, stdout);
  18}
  19
  20/*
  21 * Initialize the grep_defaults template with hardcoded defaults.
  22 * We could let the compiler do this, but without C99 initializers
  23 * the code gets unwieldy and unreadable, so...
  24 */
  25void init_grep_defaults(void)
  26{
  27        struct grep_opt *opt = &grep_defaults;
  28        static int run_once;
  29
  30        if (run_once)
  31                return;
  32        run_once++;
  33
  34        memset(opt, 0, sizeof(*opt));
  35        opt->relative = 1;
  36        opt->pathname = 1;
  37        opt->regflags = REG_NEWLINE;
  38        opt->max_depth = -1;
  39        opt->pattern_type_option = GREP_PATTERN_TYPE_UNSPECIFIED;
  40        opt->extended_regexp_option = 0;
  41        color_set(opt->color_context, "");
  42        color_set(opt->color_filename, "");
  43        color_set(opt->color_function, "");
  44        color_set(opt->color_lineno, "");
  45        color_set(opt->color_match_context, GIT_COLOR_BOLD_RED);
  46        color_set(opt->color_match_selected, GIT_COLOR_BOLD_RED);
  47        color_set(opt->color_selected, "");
  48        color_set(opt->color_sep, GIT_COLOR_CYAN);
  49        opt->color = -1;
  50        opt->output = std_output;
  51}
  52
  53static int parse_pattern_type_arg(const char *opt, const char *arg)
  54{
  55        if (!strcmp(arg, "default"))
  56                return GREP_PATTERN_TYPE_UNSPECIFIED;
  57        else if (!strcmp(arg, "basic"))
  58                return GREP_PATTERN_TYPE_BRE;
  59        else if (!strcmp(arg, "extended"))
  60                return GREP_PATTERN_TYPE_ERE;
  61        else if (!strcmp(arg, "fixed"))
  62                return GREP_PATTERN_TYPE_FIXED;
  63        else if (!strcmp(arg, "perl"))
  64                return GREP_PATTERN_TYPE_PCRE;
  65        die("bad %s argument: %s", opt, arg);
  66}
  67
  68/*
  69 * Read the configuration file once and store it in
  70 * the grep_defaults template.
  71 */
  72int grep_config(const char *var, const char *value, void *cb)
  73{
  74        struct grep_opt *opt = &grep_defaults;
  75        char *color = NULL;
  76
  77        if (userdiff_config(var, value) < 0)
  78                return -1;
  79
  80        if (!strcmp(var, "grep.extendedregexp")) {
  81                if (git_config_bool(var, value))
  82                        opt->extended_regexp_option = 1;
  83                else
  84                        opt->extended_regexp_option = 0;
  85                return 0;
  86        }
  87
  88        if (!strcmp(var, "grep.patterntype")) {
  89                opt->pattern_type_option = parse_pattern_type_arg(var, value);
  90                return 0;
  91        }
  92
  93        if (!strcmp(var, "grep.linenumber")) {
  94                opt->linenum = git_config_bool(var, value);
  95                return 0;
  96        }
  97
  98        if (!strcmp(var, "grep.fullname")) {
  99                opt->relative = !git_config_bool(var, value);
 100                return 0;
 101        }
 102
 103        if (!strcmp(var, "color.grep"))
 104                opt->color = git_config_colorbool(var, value);
 105        else if (!strcmp(var, "color.grep.context"))
 106                color = opt->color_context;
 107        else if (!strcmp(var, "color.grep.filename"))
 108                color = opt->color_filename;
 109        else if (!strcmp(var, "color.grep.function"))
 110                color = opt->color_function;
 111        else if (!strcmp(var, "color.grep.linenumber"))
 112                color = opt->color_lineno;
 113        else if (!strcmp(var, "color.grep.matchcontext"))
 114                color = opt->color_match_context;
 115        else if (!strcmp(var, "color.grep.matchselected"))
 116                color = opt->color_match_selected;
 117        else if (!strcmp(var, "color.grep.selected"))
 118                color = opt->color_selected;
 119        else if (!strcmp(var, "color.grep.separator"))
 120                color = opt->color_sep;
 121        else if (!strcmp(var, "color.grep.match")) {
 122                int rc = 0;
 123                if (!value)
 124                        return config_error_nonbool(var);
 125                rc |= color_parse(value, opt->color_match_context);
 126                rc |= color_parse(value, opt->color_match_selected);
 127                return rc;
 128        }
 129
 130        if (color) {
 131                if (!value)
 132                        return config_error_nonbool(var);
 133                return color_parse(value, color);
 134        }
 135        return 0;
 136}
 137
 138/*
 139 * Initialize one instance of grep_opt and copy the
 140 * default values from the template we read the configuration
 141 * information in an earlier call to git_config(grep_config).
 142 */
 143void grep_init(struct grep_opt *opt, const char *prefix)
 144{
 145        struct grep_opt *def = &grep_defaults;
 146
 147        memset(opt, 0, sizeof(*opt));
 148        opt->prefix = prefix;
 149        opt->prefix_length = (prefix && *prefix) ? strlen(prefix) : 0;
 150        opt->pattern_tail = &opt->pattern_list;
 151        opt->header_tail = &opt->header_list;
 152
 153        opt->color = def->color;
 154        opt->extended_regexp_option = def->extended_regexp_option;
 155        opt->pattern_type_option = def->pattern_type_option;
 156        opt->linenum = def->linenum;
 157        opt->max_depth = def->max_depth;
 158        opt->pathname = def->pathname;
 159        opt->regflags = def->regflags;
 160        opt->relative = def->relative;
 161        opt->output = def->output;
 162
 163        color_set(opt->color_context, def->color_context);
 164        color_set(opt->color_filename, def->color_filename);
 165        color_set(opt->color_function, def->color_function);
 166        color_set(opt->color_lineno, def->color_lineno);
 167        color_set(opt->color_match_context, def->color_match_context);
 168        color_set(opt->color_match_selected, def->color_match_selected);
 169        color_set(opt->color_selected, def->color_selected);
 170        color_set(opt->color_sep, def->color_sep);
 171}
 172
 173static void grep_set_pattern_type_option(enum grep_pattern_type pattern_type, struct grep_opt *opt)
 174{
 175        switch (pattern_type) {
 176        case GREP_PATTERN_TYPE_UNSPECIFIED:
 177                /* fall through */
 178
 179        case GREP_PATTERN_TYPE_BRE:
 180                opt->fixed = 0;
 181                opt->pcre = 0;
 182                break;
 183
 184        case GREP_PATTERN_TYPE_ERE:
 185                opt->fixed = 0;
 186                opt->pcre = 0;
 187                opt->regflags |= REG_EXTENDED;
 188                break;
 189
 190        case GREP_PATTERN_TYPE_FIXED:
 191                opt->fixed = 1;
 192                opt->pcre = 0;
 193                break;
 194
 195        case GREP_PATTERN_TYPE_PCRE:
 196                opt->fixed = 0;
 197                opt->pcre = 1;
 198                break;
 199        }
 200}
 201
 202void grep_commit_pattern_type(enum grep_pattern_type pattern_type, struct grep_opt *opt)
 203{
 204        if (pattern_type != GREP_PATTERN_TYPE_UNSPECIFIED)
 205                grep_set_pattern_type_option(pattern_type, opt);
 206        else if (opt->pattern_type_option != GREP_PATTERN_TYPE_UNSPECIFIED)
 207                grep_set_pattern_type_option(opt->pattern_type_option, opt);
 208        else if (opt->extended_regexp_option)
 209                grep_set_pattern_type_option(GREP_PATTERN_TYPE_ERE, opt);
 210}
 211
 212static struct grep_pat *create_grep_pat(const char *pat, size_t patlen,
 213                                        const char *origin, int no,
 214                                        enum grep_pat_token t,
 215                                        enum grep_header_field field)
 216{
 217        struct grep_pat *p = xcalloc(1, sizeof(*p));
 218        p->pattern = xmemdupz(pat, patlen);
 219        p->patternlen = patlen;
 220        p->origin = origin;
 221        p->no = no;
 222        p->token = t;
 223        p->field = field;
 224        return p;
 225}
 226
 227static void do_append_grep_pat(struct grep_pat ***tail, struct grep_pat *p)
 228{
 229        **tail = p;
 230        *tail = &p->next;
 231        p->next = NULL;
 232
 233        switch (p->token) {
 234        case GREP_PATTERN: /* atom */
 235        case GREP_PATTERN_HEAD:
 236        case GREP_PATTERN_BODY:
 237                for (;;) {
 238                        struct grep_pat *new_pat;
 239                        size_t len = 0;
 240                        char *cp = p->pattern + p->patternlen, *nl = NULL;
 241                        while (++len <= p->patternlen) {
 242                                if (*(--cp) == '\n') {
 243                                        nl = cp;
 244                                        break;
 245                                }
 246                        }
 247                        if (!nl)
 248                                break;
 249                        new_pat = create_grep_pat(nl + 1, len - 1, p->origin,
 250                                                  p->no, p->token, p->field);
 251                        new_pat->next = p->next;
 252                        if (!p->next)
 253                                *tail = &new_pat->next;
 254                        p->next = new_pat;
 255                        *nl = '\0';
 256                        p->patternlen -= len;
 257                }
 258                break;
 259        default:
 260                break;
 261        }
 262}
 263
 264void append_header_grep_pattern(struct grep_opt *opt,
 265                                enum grep_header_field field, const char *pat)
 266{
 267        struct grep_pat *p = create_grep_pat(pat, strlen(pat), "header", 0,
 268                                             GREP_PATTERN_HEAD, field);
 269        if (field == GREP_HEADER_REFLOG)
 270                opt->use_reflog_filter = 1;
 271        do_append_grep_pat(&opt->header_tail, p);
 272}
 273
 274void append_grep_pattern(struct grep_opt *opt, const char *pat,
 275                         const char *origin, int no, enum grep_pat_token t)
 276{
 277        append_grep_pat(opt, pat, strlen(pat), origin, no, t);
 278}
 279
 280void append_grep_pat(struct grep_opt *opt, const char *pat, size_t patlen,
 281                     const char *origin, int no, enum grep_pat_token t)
 282{
 283        struct grep_pat *p = create_grep_pat(pat, patlen, origin, no, t, 0);
 284        do_append_grep_pat(&opt->pattern_tail, p);
 285}
 286
 287struct grep_opt *grep_opt_dup(const struct grep_opt *opt)
 288{
 289        struct grep_pat *pat;
 290        struct grep_opt *ret = xmalloc(sizeof(struct grep_opt));
 291        *ret = *opt;
 292
 293        ret->pattern_list = NULL;
 294        ret->pattern_tail = &ret->pattern_list;
 295
 296        for(pat = opt->pattern_list; pat != NULL; pat = pat->next)
 297        {
 298                if(pat->token == GREP_PATTERN_HEAD)
 299                        append_header_grep_pattern(ret, pat->field,
 300                                                   pat->pattern);
 301                else
 302                        append_grep_pat(ret, pat->pattern, pat->patternlen,
 303                                        pat->origin, pat->no, pat->token);
 304        }
 305
 306        return ret;
 307}
 308
 309static NORETURN void compile_regexp_failed(const struct grep_pat *p,
 310                const char *error)
 311{
 312        char where[1024];
 313
 314        if (p->no)
 315                xsnprintf(where, sizeof(where), "In '%s' at %d, ", p->origin, p->no);
 316        else if (p->origin)
 317                xsnprintf(where, sizeof(where), "%s, ", p->origin);
 318        else
 319                where[0] = 0;
 320
 321        die("%s'%s': %s", where, p->pattern, error);
 322}
 323
 324#ifdef USE_LIBPCRE
 325static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 326{
 327        const char *error;
 328        int erroffset;
 329        int options = PCRE_MULTILINE;
 330
 331        if (opt->ignore_case) {
 332                if (has_non_ascii(p->pattern))
 333                        p->pcre_tables = pcre_maketables();
 334                options |= PCRE_CASELESS;
 335        }
 336        if (is_utf8_locale() && has_non_ascii(p->pattern))
 337                options |= PCRE_UTF8;
 338
 339        p->pcre_regexp = pcre_compile(p->pattern, options, &error, &erroffset,
 340                                      p->pcre_tables);
 341        if (!p->pcre_regexp)
 342                compile_regexp_failed(p, error);
 343
 344        p->pcre_extra_info = pcre_study(p->pcre_regexp, 0, &error);
 345        if (!p->pcre_extra_info && error)
 346                die("%s", error);
 347}
 348
 349static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 350                regmatch_t *match, int eflags)
 351{
 352        int ovector[30], ret, flags = 0;
 353
 354        if (eflags & REG_NOTBOL)
 355                flags |= PCRE_NOTBOL;
 356
 357        ret = pcre_exec(p->pcre_regexp, p->pcre_extra_info, line, eol - line,
 358                        0, flags, ovector, ARRAY_SIZE(ovector));
 359        if (ret < 0 && ret != PCRE_ERROR_NOMATCH)
 360                die("pcre_exec failed with error code %d", ret);
 361        if (ret > 0) {
 362                ret = 0;
 363                match->rm_so = ovector[0];
 364                match->rm_eo = ovector[1];
 365        }
 366
 367        return ret;
 368}
 369
 370static void free_pcre_regexp(struct grep_pat *p)
 371{
 372        pcre_free(p->pcre_regexp);
 373        pcre_free(p->pcre_extra_info);
 374        pcre_free((void *)p->pcre_tables);
 375}
 376#else /* !USE_LIBPCRE */
 377static void compile_pcre_regexp(struct grep_pat *p, const struct grep_opt *opt)
 378{
 379        die("cannot use Perl-compatible regexes when not compiled with USE_LIBPCRE");
 380}
 381
 382static int pcrematch(struct grep_pat *p, const char *line, const char *eol,
 383                regmatch_t *match, int eflags)
 384{
 385        return 1;
 386}
 387
 388static void free_pcre_regexp(struct grep_pat *p)
 389{
 390}
 391#endif /* !USE_LIBPCRE */
 392
 393static int is_fixed(const char *s, size_t len)
 394{
 395        size_t i;
 396
 397        /* regcomp cannot accept patterns with NULs so we
 398         * consider any pattern containing a NUL fixed.
 399         */
 400        if (memchr(s, 0, len))
 401                return 1;
 402
 403        for (i = 0; i < len; i++) {
 404                if (is_regex_special(s[i]))
 405                        return 0;
 406        }
 407
 408        return 1;
 409}
 410
 411static void compile_fixed_regexp(struct grep_pat *p, struct grep_opt *opt)
 412{
 413        struct strbuf sb = STRBUF_INIT;
 414        int err;
 415        int regflags = opt->regflags;
 416
 417        basic_regex_quote_buf(&sb, p->pattern);
 418        if (opt->ignore_case)
 419                regflags |= REG_ICASE;
 420        err = regcomp(&p->regexp, sb.buf, regflags);
 421        if (opt->debug)
 422                fprintf(stderr, "fixed %s\n", sb.buf);
 423        strbuf_release(&sb);
 424        if (err) {
 425                char errbuf[1024];
 426                regerror(err, &p->regexp, errbuf, sizeof(errbuf));
 427                regfree(&p->regexp);
 428                compile_regexp_failed(p, errbuf);
 429        }
 430}
 431
 432static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
 433{
 434        int icase, ascii_only;
 435        int err;
 436
 437        p->word_regexp = opt->word_regexp;
 438        p->ignore_case = opt->ignore_case;
 439        icase          = opt->regflags & REG_ICASE || p->ignore_case;
 440        ascii_only     = !has_non_ascii(p->pattern);
 441
 442        /*
 443         * Even when -F (fixed) asks us to do a non-regexp search, we
 444         * may not be able to correctly case-fold when -i
 445         * (ignore-case) is asked (in which case, we'll synthesize a
 446         * regexp to match the pattern that matches regexp special
 447         * characters literally, while ignoring case differences).  On
 448         * the other hand, even without -F, if the pattern does not
 449         * have any regexp special characters and there is no need for
 450         * case-folding search, we can internally turn it into a
 451         * simple string match using kws.  p->fixed tells us if we
 452         * want to use kws.
 453         */
 454        if (opt->fixed || is_fixed(p->pattern, p->patternlen))
 455                p->fixed = !icase || ascii_only;
 456        else
 457                p->fixed = 0;
 458
 459        if (p->fixed) {
 460                p->kws = kwsalloc(icase ? tolower_trans_tbl : NULL);
 461                kwsincr(p->kws, p->pattern, p->patternlen);
 462                kwsprep(p->kws);
 463                return;
 464        } else if (opt->fixed) {
 465                /*
 466                 * We come here when the pattern has the non-ascii
 467                 * characters we cannot case-fold, and asked to
 468                 * ignore-case.
 469                 */
 470                compile_fixed_regexp(p, opt);
 471                return;
 472        }
 473
 474        if (opt->pcre) {
 475                compile_pcre_regexp(p, opt);
 476                return;
 477        }
 478
 479        err = regcomp(&p->regexp, p->pattern, opt->regflags);
 480        if (err) {
 481                char errbuf[1024];
 482                regerror(err, &p->regexp, errbuf, 1024);
 483                regfree(&p->regexp);
 484                compile_regexp_failed(p, errbuf);
 485        }
 486}
 487
 488static struct grep_expr *compile_pattern_or(struct grep_pat **);
 489static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
 490{
 491        struct grep_pat *p;
 492        struct grep_expr *x;
 493
 494        p = *list;
 495        if (!p)
 496                return NULL;
 497        switch (p->token) {
 498        case GREP_PATTERN: /* atom */
 499        case GREP_PATTERN_HEAD:
 500        case GREP_PATTERN_BODY:
 501                x = xcalloc(1, sizeof (struct grep_expr));
 502                x->node = GREP_NODE_ATOM;
 503                x->u.atom = p;
 504                *list = p->next;
 505                return x;
 506        case GREP_OPEN_PAREN:
 507                *list = p->next;
 508                x = compile_pattern_or(list);
 509                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
 510                        die("unmatched parenthesis");
 511                *list = (*list)->next;
 512                return x;
 513        default:
 514                return NULL;
 515        }
 516}
 517
 518static struct grep_expr *compile_pattern_not(struct grep_pat **list)
 519{
 520        struct grep_pat *p;
 521        struct grep_expr *x;
 522
 523        p = *list;
 524        if (!p)
 525                return NULL;
 526        switch (p->token) {
 527        case GREP_NOT:
 528                if (!p->next)
 529                        die("--not not followed by pattern expression");
 530                *list = p->next;
 531                x = xcalloc(1, sizeof (struct grep_expr));
 532                x->node = GREP_NODE_NOT;
 533                x->u.unary = compile_pattern_not(list);
 534                if (!x->u.unary)
 535                        die("--not followed by non pattern expression");
 536                return x;
 537        default:
 538                return compile_pattern_atom(list);
 539        }
 540}
 541
 542static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 543{
 544        struct grep_pat *p;
 545        struct grep_expr *x, *y, *z;
 546
 547        x = compile_pattern_not(list);
 548        p = *list;
 549        if (p && p->token == GREP_AND) {
 550                if (!p->next)
 551                        die("--and not followed by pattern expression");
 552                *list = p->next;
 553                y = compile_pattern_and(list);
 554                if (!y)
 555                        die("--and not followed by pattern expression");
 556                z = xcalloc(1, sizeof (struct grep_expr));
 557                z->node = GREP_NODE_AND;
 558                z->u.binary.left = x;
 559                z->u.binary.right = y;
 560                return z;
 561        }
 562        return x;
 563}
 564
 565static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 566{
 567        struct grep_pat *p;
 568        struct grep_expr *x, *y, *z;
 569
 570        x = compile_pattern_and(list);
 571        p = *list;
 572        if (x && p && p->token != GREP_CLOSE_PAREN) {
 573                y = compile_pattern_or(list);
 574                if (!y)
 575                        die("not a pattern expression %s", p->pattern);
 576                z = xcalloc(1, sizeof (struct grep_expr));
 577                z->node = GREP_NODE_OR;
 578                z->u.binary.left = x;
 579                z->u.binary.right = y;
 580                return z;
 581        }
 582        return x;
 583}
 584
 585static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 586{
 587        return compile_pattern_or(list);
 588}
 589
 590static void indent(int in)
 591{
 592        while (in-- > 0)
 593                fputc(' ', stderr);
 594}
 595
 596static void dump_grep_pat(struct grep_pat *p)
 597{
 598        switch (p->token) {
 599        case GREP_AND: fprintf(stderr, "*and*"); break;
 600        case GREP_OPEN_PAREN: fprintf(stderr, "*(*"); break;
 601        case GREP_CLOSE_PAREN: fprintf(stderr, "*)*"); break;
 602        case GREP_NOT: fprintf(stderr, "*not*"); break;
 603        case GREP_OR: fprintf(stderr, "*or*"); break;
 604
 605        case GREP_PATTERN: fprintf(stderr, "pattern"); break;
 606        case GREP_PATTERN_HEAD: fprintf(stderr, "pattern_head"); break;
 607        case GREP_PATTERN_BODY: fprintf(stderr, "pattern_body"); break;
 608        }
 609
 610        switch (p->token) {
 611        default: break;
 612        case GREP_PATTERN_HEAD:
 613                fprintf(stderr, "<head %d>", p->field); break;
 614        case GREP_PATTERN_BODY:
 615                fprintf(stderr, "<body>"); break;
 616        }
 617        switch (p->token) {
 618        default: break;
 619        case GREP_PATTERN_HEAD:
 620        case GREP_PATTERN_BODY:
 621        case GREP_PATTERN:
 622                fprintf(stderr, "%.*s", (int)p->patternlen, p->pattern);
 623                break;
 624        }
 625        fputc('\n', stderr);
 626}
 627
 628static void dump_grep_expression_1(struct grep_expr *x, int in)
 629{
 630        indent(in);
 631        switch (x->node) {
 632        case GREP_NODE_TRUE:
 633                fprintf(stderr, "true\n");
 634                break;
 635        case GREP_NODE_ATOM:
 636                dump_grep_pat(x->u.atom);
 637                break;
 638        case GREP_NODE_NOT:
 639                fprintf(stderr, "(not\n");
 640                dump_grep_expression_1(x->u.unary, in+1);
 641                indent(in);
 642                fprintf(stderr, ")\n");
 643                break;
 644        case GREP_NODE_AND:
 645                fprintf(stderr, "(and\n");
 646                dump_grep_expression_1(x->u.binary.left, in+1);
 647                dump_grep_expression_1(x->u.binary.right, in+1);
 648                indent(in);
 649                fprintf(stderr, ")\n");
 650                break;
 651        case GREP_NODE_OR:
 652                fprintf(stderr, "(or\n");
 653                dump_grep_expression_1(x->u.binary.left, in+1);
 654                dump_grep_expression_1(x->u.binary.right, in+1);
 655                indent(in);
 656                fprintf(stderr, ")\n");
 657                break;
 658        }
 659}
 660
 661static void dump_grep_expression(struct grep_opt *opt)
 662{
 663        struct grep_expr *x = opt->pattern_expression;
 664
 665        if (opt->all_match)
 666                fprintf(stderr, "[all-match]\n");
 667        dump_grep_expression_1(x, 0);
 668        fflush(NULL);
 669}
 670
 671static struct grep_expr *grep_true_expr(void)
 672{
 673        struct grep_expr *z = xcalloc(1, sizeof(*z));
 674        z->node = GREP_NODE_TRUE;
 675        return z;
 676}
 677
 678static struct grep_expr *grep_or_expr(struct grep_expr *left, struct grep_expr *right)
 679{
 680        struct grep_expr *z = xcalloc(1, sizeof(*z));
 681        z->node = GREP_NODE_OR;
 682        z->u.binary.left = left;
 683        z->u.binary.right = right;
 684        return z;
 685}
 686
 687static struct grep_expr *prep_header_patterns(struct grep_opt *opt)
 688{
 689        struct grep_pat *p;
 690        struct grep_expr *header_expr;
 691        struct grep_expr *(header_group[GREP_HEADER_FIELD_MAX]);
 692        enum grep_header_field fld;
 693
 694        if (!opt->header_list)
 695                return NULL;
 696
 697        for (p = opt->header_list; p; p = p->next) {
 698                if (p->token != GREP_PATTERN_HEAD)
 699                        die("BUG: a non-header pattern in grep header list.");
 700                if (p->field < GREP_HEADER_FIELD_MIN ||
 701                    GREP_HEADER_FIELD_MAX <= p->field)
 702                        die("BUG: unknown header field %d", p->field);
 703                compile_regexp(p, opt);
 704        }
 705
 706        for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++)
 707                header_group[fld] = NULL;
 708
 709        for (p = opt->header_list; p; p = p->next) {
 710                struct grep_expr *h;
 711                struct grep_pat *pp = p;
 712
 713                h = compile_pattern_atom(&pp);
 714                if (!h || pp != p->next)
 715                        die("BUG: malformed header expr");
 716                if (!header_group[p->field]) {
 717                        header_group[p->field] = h;
 718                        continue;
 719                }
 720                header_group[p->field] = grep_or_expr(h, header_group[p->field]);
 721        }
 722
 723        header_expr = NULL;
 724
 725        for (fld = 0; fld < GREP_HEADER_FIELD_MAX; fld++) {
 726                if (!header_group[fld])
 727                        continue;
 728                if (!header_expr)
 729                        header_expr = grep_true_expr();
 730                header_expr = grep_or_expr(header_group[fld], header_expr);
 731        }
 732        return header_expr;
 733}
 734
 735static struct grep_expr *grep_splice_or(struct grep_expr *x, struct grep_expr *y)
 736{
 737        struct grep_expr *z = x;
 738
 739        while (x) {
 740                assert(x->node == GREP_NODE_OR);
 741                if (x->u.binary.right &&
 742                    x->u.binary.right->node == GREP_NODE_TRUE) {
 743                        x->u.binary.right = y;
 744                        break;
 745                }
 746                x = x->u.binary.right;
 747        }
 748        return z;
 749}
 750
 751static void compile_grep_patterns_real(struct grep_opt *opt)
 752{
 753        struct grep_pat *p;
 754        struct grep_expr *header_expr = prep_header_patterns(opt);
 755
 756        for (p = opt->pattern_list; p; p = p->next) {
 757                switch (p->token) {
 758                case GREP_PATTERN: /* atom */
 759                case GREP_PATTERN_HEAD:
 760                case GREP_PATTERN_BODY:
 761                        compile_regexp(p, opt);
 762                        break;
 763                default:
 764                        opt->extended = 1;
 765                        break;
 766                }
 767        }
 768
 769        if (opt->all_match || header_expr)
 770                opt->extended = 1;
 771        else if (!opt->extended && !opt->debug)
 772                return;
 773
 774        p = opt->pattern_list;
 775        if (p)
 776                opt->pattern_expression = compile_pattern_expr(&p);
 777        if (p)
 778                die("incomplete pattern expression: %s", p->pattern);
 779
 780        if (!header_expr)
 781                return;
 782
 783        if (!opt->pattern_expression)
 784                opt->pattern_expression = header_expr;
 785        else if (opt->all_match)
 786                opt->pattern_expression = grep_splice_or(header_expr,
 787                                                         opt->pattern_expression);
 788        else
 789                opt->pattern_expression = grep_or_expr(opt->pattern_expression,
 790                                                       header_expr);
 791        opt->all_match = 1;
 792}
 793
 794void compile_grep_patterns(struct grep_opt *opt)
 795{
 796        compile_grep_patterns_real(opt);
 797        if (opt->debug)
 798                dump_grep_expression(opt);
 799}
 800
 801static void free_pattern_expr(struct grep_expr *x)
 802{
 803        switch (x->node) {
 804        case GREP_NODE_TRUE:
 805        case GREP_NODE_ATOM:
 806                break;
 807        case GREP_NODE_NOT:
 808                free_pattern_expr(x->u.unary);
 809                break;
 810        case GREP_NODE_AND:
 811        case GREP_NODE_OR:
 812                free_pattern_expr(x->u.binary.left);
 813                free_pattern_expr(x->u.binary.right);
 814                break;
 815        }
 816        free(x);
 817}
 818
 819void free_grep_patterns(struct grep_opt *opt)
 820{
 821        struct grep_pat *p, *n;
 822
 823        for (p = opt->pattern_list; p; p = n) {
 824                n = p->next;
 825                switch (p->token) {
 826                case GREP_PATTERN: /* atom */
 827                case GREP_PATTERN_HEAD:
 828                case GREP_PATTERN_BODY:
 829                        if (p->kws)
 830                                kwsfree(p->kws);
 831                        else if (p->pcre_regexp)
 832                                free_pcre_regexp(p);
 833                        else
 834                                regfree(&p->regexp);
 835                        free(p->pattern);
 836                        break;
 837                default:
 838                        break;
 839                }
 840                free(p);
 841        }
 842
 843        if (!opt->extended)
 844                return;
 845        free_pattern_expr(opt->pattern_expression);
 846}
 847
 848static char *end_of_line(char *cp, unsigned long *left)
 849{
 850        unsigned long l = *left;
 851        while (l && *cp != '\n') {
 852                l--;
 853                cp++;
 854        }
 855        *left = l;
 856        return cp;
 857}
 858
 859static int word_char(char ch)
 860{
 861        return isalnum(ch) || ch == '_';
 862}
 863
 864static void output_color(struct grep_opt *opt, const void *data, size_t size,
 865                         const char *color)
 866{
 867        if (want_color(opt->color) && color && color[0]) {
 868                opt->output(opt, color, strlen(color));
 869                opt->output(opt, data, size);
 870                opt->output(opt, GIT_COLOR_RESET, strlen(GIT_COLOR_RESET));
 871        } else
 872                opt->output(opt, data, size);
 873}
 874
 875static void output_sep(struct grep_opt *opt, char sign)
 876{
 877        if (opt->null_following_name)
 878                opt->output(opt, "\0", 1);
 879        else
 880                output_color(opt, &sign, 1, opt->color_sep);
 881}
 882
 883static void show_name(struct grep_opt *opt, const char *name)
 884{
 885        output_color(opt, name, strlen(name), opt->color_filename);
 886        opt->output(opt, opt->null_following_name ? "\0" : "\n", 1);
 887}
 888
 889static int fixmatch(struct grep_pat *p, char *line, char *eol,
 890                    regmatch_t *match)
 891{
 892        struct kwsmatch kwsm;
 893        size_t offset = kwsexec(p->kws, line, eol - line, &kwsm);
 894        if (offset == -1) {
 895                match->rm_so = match->rm_eo = -1;
 896                return REG_NOMATCH;
 897        } else {
 898                match->rm_so = offset;
 899                match->rm_eo = match->rm_so + kwsm.size[0];
 900                return 0;
 901        }
 902}
 903
 904static int patmatch(struct grep_pat *p, char *line, char *eol,
 905                    regmatch_t *match, int eflags)
 906{
 907        int hit;
 908
 909        if (p->fixed)
 910                hit = !fixmatch(p, line, eol, match);
 911        else if (p->pcre_regexp)
 912                hit = !pcrematch(p, line, eol, match, eflags);
 913        else
 914                hit = !regexec_buf(&p->regexp, line, eol - line, 1, match,
 915                                   eflags);
 916
 917        return hit;
 918}
 919
 920static int strip_timestamp(char *bol, char **eol_p)
 921{
 922        char *eol = *eol_p;
 923        int ch;
 924
 925        while (bol < --eol) {
 926                if (*eol != '>')
 927                        continue;
 928                *eol_p = ++eol;
 929                ch = *eol;
 930                *eol = '\0';
 931                return ch;
 932        }
 933        return 0;
 934}
 935
 936static struct {
 937        const char *field;
 938        size_t len;
 939} header_field[] = {
 940        { "author ", 7 },
 941        { "committer ", 10 },
 942        { "reflog ", 7 },
 943};
 944
 945static int match_one_pattern(struct grep_pat *p, char *bol, char *eol,
 946                             enum grep_context ctx,
 947                             regmatch_t *pmatch, int eflags)
 948{
 949        int hit = 0;
 950        int saved_ch = 0;
 951        const char *start = bol;
 952
 953        if ((p->token != GREP_PATTERN) &&
 954            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 955                return 0;
 956
 957        if (p->token == GREP_PATTERN_HEAD) {
 958                const char *field;
 959                size_t len;
 960                assert(p->field < ARRAY_SIZE(header_field));
 961                field = header_field[p->field].field;
 962                len = header_field[p->field].len;
 963                if (strncmp(bol, field, len))
 964                        return 0;
 965                bol += len;
 966                switch (p->field) {
 967                case GREP_HEADER_AUTHOR:
 968                case GREP_HEADER_COMMITTER:
 969                        saved_ch = strip_timestamp(bol, &eol);
 970                        break;
 971                default:
 972                        break;
 973                }
 974        }
 975
 976 again:
 977        hit = patmatch(p, bol, eol, pmatch, eflags);
 978
 979        if (hit && p->word_regexp) {
 980                if ((pmatch[0].rm_so < 0) ||
 981                    (eol - bol) < pmatch[0].rm_so ||
 982                    (pmatch[0].rm_eo < 0) ||
 983                    (eol - bol) < pmatch[0].rm_eo)
 984                        die("regexp returned nonsense");
 985
 986                /* Match beginning must be either beginning of the
 987                 * line, or at word boundary (i.e. the last char must
 988                 * not be a word char).  Similarly, match end must be
 989                 * either end of the line, or at word boundary
 990                 * (i.e. the next char must not be a word char).
 991                 */
 992                if ( ((pmatch[0].rm_so == 0) ||
 993                      !word_char(bol[pmatch[0].rm_so-1])) &&
 994                     ((pmatch[0].rm_eo == (eol-bol)) ||
 995                      !word_char(bol[pmatch[0].rm_eo])) )
 996                        ;
 997                else
 998                        hit = 0;
 999
1000                /* Words consist of at least one character. */
1001                if (pmatch->rm_so == pmatch->rm_eo)
1002                        hit = 0;
1003
1004                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
1005                        /* There could be more than one match on the
1006                         * line, and the first match might not be
1007                         * strict word match.  But later ones could be!
1008                         * Forward to the next possible start, i.e. the
1009                         * next position following a non-word char.
1010                         */
1011                        bol = pmatch[0].rm_so + bol + 1;
1012                        while (word_char(bol[-1]) && bol < eol)
1013                                bol++;
1014                        eflags |= REG_NOTBOL;
1015                        if (bol < eol)
1016                                goto again;
1017                }
1018        }
1019        if (p->token == GREP_PATTERN_HEAD && saved_ch)
1020                *eol = saved_ch;
1021        if (hit) {
1022                pmatch[0].rm_so += bol - start;
1023                pmatch[0].rm_eo += bol - start;
1024        }
1025        return hit;
1026}
1027
1028static int match_expr_eval(struct grep_expr *x, char *bol, char *eol,
1029                           enum grep_context ctx, int collect_hits)
1030{
1031        int h = 0;
1032        regmatch_t match;
1033
1034        if (!x)
1035                die("Not a valid grep expression");
1036        switch (x->node) {
1037        case GREP_NODE_TRUE:
1038                h = 1;
1039                break;
1040        case GREP_NODE_ATOM:
1041                h = match_one_pattern(x->u.atom, bol, eol, ctx, &match, 0);
1042                break;
1043        case GREP_NODE_NOT:
1044                h = !match_expr_eval(x->u.unary, bol, eol, ctx, 0);
1045                break;
1046        case GREP_NODE_AND:
1047                if (!match_expr_eval(x->u.binary.left, bol, eol, ctx, 0))
1048                        return 0;
1049                h = match_expr_eval(x->u.binary.right, bol, eol, ctx, 0);
1050                break;
1051        case GREP_NODE_OR:
1052                if (!collect_hits)
1053                        return (match_expr_eval(x->u.binary.left,
1054                                                bol, eol, ctx, 0) ||
1055                                match_expr_eval(x->u.binary.right,
1056                                                bol, eol, ctx, 0));
1057                h = match_expr_eval(x->u.binary.left, bol, eol, ctx, 0);
1058                x->u.binary.left->hit |= h;
1059                h |= match_expr_eval(x->u.binary.right, bol, eol, ctx, 1);
1060                break;
1061        default:
1062                die("Unexpected node type (internal error) %d", x->node);
1063        }
1064        if (collect_hits)
1065                x->hit |= h;
1066        return h;
1067}
1068
1069static int match_expr(struct grep_opt *opt, char *bol, char *eol,
1070                      enum grep_context ctx, int collect_hits)
1071{
1072        struct grep_expr *x = opt->pattern_expression;
1073        return match_expr_eval(x, bol, eol, ctx, collect_hits);
1074}
1075
1076static int match_line(struct grep_opt *opt, char *bol, char *eol,
1077                      enum grep_context ctx, int collect_hits)
1078{
1079        struct grep_pat *p;
1080        regmatch_t match;
1081
1082        if (opt->extended)
1083                return match_expr(opt, bol, eol, ctx, collect_hits);
1084
1085        /* we do not call with collect_hits without being extended */
1086        for (p = opt->pattern_list; p; p = p->next) {
1087                if (match_one_pattern(p, bol, eol, ctx, &match, 0))
1088                        return 1;
1089        }
1090        return 0;
1091}
1092
1093static int match_next_pattern(struct grep_pat *p, char *bol, char *eol,
1094                              enum grep_context ctx,
1095                              regmatch_t *pmatch, int eflags)
1096{
1097        regmatch_t match;
1098
1099        if (!match_one_pattern(p, bol, eol, ctx, &match, eflags))
1100                return 0;
1101        if (match.rm_so < 0 || match.rm_eo < 0)
1102                return 0;
1103        if (pmatch->rm_so >= 0 && pmatch->rm_eo >= 0) {
1104                if (match.rm_so > pmatch->rm_so)
1105                        return 1;
1106                if (match.rm_so == pmatch->rm_so && match.rm_eo < pmatch->rm_eo)
1107                        return 1;
1108        }
1109        pmatch->rm_so = match.rm_so;
1110        pmatch->rm_eo = match.rm_eo;
1111        return 1;
1112}
1113
1114static int next_match(struct grep_opt *opt, char *bol, char *eol,
1115                      enum grep_context ctx, regmatch_t *pmatch, int eflags)
1116{
1117        struct grep_pat *p;
1118        int hit = 0;
1119
1120        pmatch->rm_so = pmatch->rm_eo = -1;
1121        if (bol < eol) {
1122                for (p = opt->pattern_list; p; p = p->next) {
1123                        switch (p->token) {
1124                        case GREP_PATTERN: /* atom */
1125                        case GREP_PATTERN_HEAD:
1126                        case GREP_PATTERN_BODY:
1127                                hit |= match_next_pattern(p, bol, eol, ctx,
1128                                                          pmatch, eflags);
1129                                break;
1130                        default:
1131                                break;
1132                        }
1133                }
1134        }
1135        return hit;
1136}
1137
1138static void show_line(struct grep_opt *opt, char *bol, char *eol,
1139                      const char *name, unsigned lno, char sign)
1140{
1141        int rest = eol - bol;
1142        const char *match_color, *line_color = NULL;
1143
1144        if (opt->file_break && opt->last_shown == 0) {
1145                if (opt->show_hunk_mark)
1146                        opt->output(opt, "\n", 1);
1147        } else if (opt->pre_context || opt->post_context || opt->funcbody) {
1148                if (opt->last_shown == 0) {
1149                        if (opt->show_hunk_mark) {
1150                                output_color(opt, "--", 2, opt->color_sep);
1151                                opt->output(opt, "\n", 1);
1152                        }
1153                } else if (lno > opt->last_shown + 1) {
1154                        output_color(opt, "--", 2, opt->color_sep);
1155                        opt->output(opt, "\n", 1);
1156                }
1157        }
1158        if (opt->heading && opt->last_shown == 0) {
1159                output_color(opt, name, strlen(name), opt->color_filename);
1160                opt->output(opt, "\n", 1);
1161        }
1162        opt->last_shown = lno;
1163
1164        if (!opt->heading && opt->pathname) {
1165                output_color(opt, name, strlen(name), opt->color_filename);
1166                output_sep(opt, sign);
1167        }
1168        if (opt->linenum) {
1169                char buf[32];
1170                xsnprintf(buf, sizeof(buf), "%d", lno);
1171                output_color(opt, buf, strlen(buf), opt->color_lineno);
1172                output_sep(opt, sign);
1173        }
1174        if (opt->color) {
1175                regmatch_t match;
1176                enum grep_context ctx = GREP_CONTEXT_BODY;
1177                int ch = *eol;
1178                int eflags = 0;
1179
1180                if (sign == ':')
1181                        match_color = opt->color_match_selected;
1182                else
1183                        match_color = opt->color_match_context;
1184                if (sign == ':')
1185                        line_color = opt->color_selected;
1186                else if (sign == '-')
1187                        line_color = opt->color_context;
1188                else if (sign == '=')
1189                        line_color = opt->color_function;
1190                *eol = '\0';
1191                while (next_match(opt, bol, eol, ctx, &match, eflags)) {
1192                        if (match.rm_so == match.rm_eo)
1193                                break;
1194
1195                        output_color(opt, bol, match.rm_so, line_color);
1196                        output_color(opt, bol + match.rm_so,
1197                                     match.rm_eo - match.rm_so, match_color);
1198                        bol += match.rm_eo;
1199                        rest -= match.rm_eo;
1200                        eflags = REG_NOTBOL;
1201                }
1202                *eol = ch;
1203        }
1204        output_color(opt, bol, rest, line_color);
1205        opt->output(opt, "\n", 1);
1206}
1207
1208#ifndef NO_PTHREADS
1209int grep_use_locks;
1210
1211/*
1212 * This lock protects access to the gitattributes machinery, which is
1213 * not thread-safe.
1214 */
1215pthread_mutex_t grep_attr_mutex;
1216
1217static inline void grep_attr_lock(void)
1218{
1219        if (grep_use_locks)
1220                pthread_mutex_lock(&grep_attr_mutex);
1221}
1222
1223static inline void grep_attr_unlock(void)
1224{
1225        if (grep_use_locks)
1226                pthread_mutex_unlock(&grep_attr_mutex);
1227}
1228
1229/*
1230 * Same as git_attr_mutex, but protecting the thread-unsafe object db access.
1231 */
1232pthread_mutex_t grep_read_mutex;
1233
1234#else
1235#define grep_attr_lock()
1236#define grep_attr_unlock()
1237#endif
1238
1239static int match_funcname(struct grep_opt *opt, struct grep_source *gs, char *bol, char *eol)
1240{
1241        xdemitconf_t *xecfg = opt->priv;
1242        if (xecfg && !xecfg->find_func) {
1243                grep_source_load_driver(gs);
1244                if (gs->driver->funcname.pattern) {
1245                        const struct userdiff_funcname *pe = &gs->driver->funcname;
1246                        xdiff_set_find_func(xecfg, pe->pattern, pe->cflags);
1247                } else {
1248                        xecfg = opt->priv = NULL;
1249                }
1250        }
1251
1252        if (xecfg) {
1253                char buf[1];
1254                return xecfg->find_func(bol, eol - bol, buf, 1,
1255                                        xecfg->find_func_priv) >= 0;
1256        }
1257
1258        if (bol == eol)
1259                return 0;
1260        if (isalpha(*bol) || *bol == '_' || *bol == '$')
1261                return 1;
1262        return 0;
1263}
1264
1265static void show_funcname_line(struct grep_opt *opt, struct grep_source *gs,
1266                               char *bol, unsigned lno)
1267{
1268        while (bol > gs->buf) {
1269                char *eol = --bol;
1270
1271                while (bol > gs->buf && bol[-1] != '\n')
1272                        bol--;
1273                lno--;
1274
1275                if (lno <= opt->last_shown)
1276                        break;
1277
1278                if (match_funcname(opt, gs, bol, eol)) {
1279                        show_line(opt, bol, eol, gs->name, lno, '=');
1280                        break;
1281                }
1282        }
1283}
1284
1285static void show_pre_context(struct grep_opt *opt, struct grep_source *gs,
1286                             char *bol, char *end, unsigned lno)
1287{
1288        unsigned cur = lno, from = 1, funcname_lno = 0;
1289        int funcname_needed = !!opt->funcname;
1290
1291        if (opt->funcbody && !match_funcname(opt, gs, bol, end))
1292                funcname_needed = 2;
1293
1294        if (opt->pre_context < lno)
1295                from = lno - opt->pre_context;
1296        if (from <= opt->last_shown)
1297                from = opt->last_shown + 1;
1298
1299        /* Rewind. */
1300        while (bol > gs->buf &&
1301               cur > (funcname_needed == 2 ? opt->last_shown + 1 : from)) {
1302                char *eol = --bol;
1303
1304                while (bol > gs->buf && bol[-1] != '\n')
1305                        bol--;
1306                cur--;
1307                if (funcname_needed && match_funcname(opt, gs, bol, eol)) {
1308                        funcname_lno = cur;
1309                        funcname_needed = 0;
1310                }
1311        }
1312
1313        /* We need to look even further back to find a function signature. */
1314        if (opt->funcname && funcname_needed)
1315                show_funcname_line(opt, gs, bol, cur);
1316
1317        /* Back forward. */
1318        while (cur < lno) {
1319                char *eol = bol, sign = (cur == funcname_lno) ? '=' : '-';
1320
1321                while (*eol != '\n')
1322                        eol++;
1323                show_line(opt, bol, eol, gs->name, cur, sign);
1324                bol = eol + 1;
1325                cur++;
1326        }
1327}
1328
1329static int should_lookahead(struct grep_opt *opt)
1330{
1331        struct grep_pat *p;
1332
1333        if (opt->extended)
1334                return 0; /* punt for too complex stuff */
1335        if (opt->invert)
1336                return 0;
1337        for (p = opt->pattern_list; p; p = p->next) {
1338                if (p->token != GREP_PATTERN)
1339                        return 0; /* punt for "header only" and stuff */
1340        }
1341        return 1;
1342}
1343
1344static int look_ahead(struct grep_opt *opt,
1345                      unsigned long *left_p,
1346                      unsigned *lno_p,
1347                      char **bol_p)
1348{
1349        unsigned lno = *lno_p;
1350        char *bol = *bol_p;
1351        struct grep_pat *p;
1352        char *sp, *last_bol;
1353        regoff_t earliest = -1;
1354
1355        for (p = opt->pattern_list; p; p = p->next) {
1356                int hit;
1357                regmatch_t m;
1358
1359                hit = patmatch(p, bol, bol + *left_p, &m, 0);
1360                if (!hit || m.rm_so < 0 || m.rm_eo < 0)
1361                        continue;
1362                if (earliest < 0 || m.rm_so < earliest)
1363                        earliest = m.rm_so;
1364        }
1365
1366        if (earliest < 0) {
1367                *bol_p = bol + *left_p;
1368                *left_p = 0;
1369                return 1;
1370        }
1371        for (sp = bol + earliest; bol < sp && sp[-1] != '\n'; sp--)
1372                ; /* find the beginning of the line */
1373        last_bol = sp;
1374
1375        for (sp = bol; sp < last_bol; sp++) {
1376                if (*sp == '\n')
1377                        lno++;
1378        }
1379        *left_p -= last_bol - bol;
1380        *bol_p = last_bol;
1381        *lno_p = lno;
1382        return 0;
1383}
1384
1385static int fill_textconv_grep(struct userdiff_driver *driver,
1386                              struct grep_source *gs)
1387{
1388        struct diff_filespec *df;
1389        char *buf;
1390        size_t size;
1391
1392        if (!driver || !driver->textconv)
1393                return grep_source_load(gs);
1394
1395        /*
1396         * The textconv interface is intimately tied to diff_filespecs, so we
1397         * have to pretend to be one. If we could unify the grep_source
1398         * and diff_filespec structs, this mess could just go away.
1399         */
1400        df = alloc_filespec(gs->path);
1401        switch (gs->type) {
1402        case GREP_SOURCE_SHA1:
1403                fill_filespec(df, gs->identifier, 1, 0100644);
1404                break;
1405        case GREP_SOURCE_FILE:
1406                fill_filespec(df, null_sha1, 0, 0100644);
1407                break;
1408        default:
1409                die("BUG: attempt to textconv something without a path?");
1410        }
1411
1412        /*
1413         * fill_textconv is not remotely thread-safe; it may load objects
1414         * behind the scenes, and it modifies the global diff tempfile
1415         * structure.
1416         */
1417        grep_read_lock();
1418        size = fill_textconv(driver, df, &buf);
1419        grep_read_unlock();
1420        free_filespec(df);
1421
1422        /*
1423         * The normal fill_textconv usage by the diff machinery would just keep
1424         * the textconv'd buf separate from the diff_filespec. But much of the
1425         * grep code passes around a grep_source and assumes that its "buf"
1426         * pointer is the beginning of the thing we are searching. So let's
1427         * install our textconv'd version into the grep_source, taking care not
1428         * to leak any existing buffer.
1429         */
1430        grep_source_clear_data(gs);
1431        gs->buf = buf;
1432        gs->size = size;
1433
1434        return 0;
1435}
1436
1437static int is_empty_line(const char *bol, const char *eol)
1438{
1439        while (bol < eol && isspace(*bol))
1440                bol++;
1441        return bol == eol;
1442}
1443
1444static int grep_source_1(struct grep_opt *opt, struct grep_source *gs, int collect_hits)
1445{
1446        char *bol;
1447        char *peek_bol = NULL;
1448        unsigned long left;
1449        unsigned lno = 1;
1450        unsigned last_hit = 0;
1451        int binary_match_only = 0;
1452        unsigned count = 0;
1453        int try_lookahead = 0;
1454        int show_function = 0;
1455        struct userdiff_driver *textconv = NULL;
1456        enum grep_context ctx = GREP_CONTEXT_HEAD;
1457        xdemitconf_t xecfg;
1458
1459        if (!opt->output)
1460                opt->output = std_output;
1461
1462        if (opt->pre_context || opt->post_context || opt->file_break ||
1463            opt->funcbody) {
1464                /* Show hunk marks, except for the first file. */
1465                if (opt->last_shown)
1466                        opt->show_hunk_mark = 1;
1467                /*
1468                 * If we're using threads then we can't easily identify
1469                 * the first file.  Always put hunk marks in that case
1470                 * and skip the very first one later in work_done().
1471                 */
1472                if (opt->output != std_output)
1473                        opt->show_hunk_mark = 1;
1474        }
1475        opt->last_shown = 0;
1476
1477        if (opt->allow_textconv) {
1478                grep_source_load_driver(gs);
1479                /*
1480                 * We might set up the shared textconv cache data here, which
1481                 * is not thread-safe.
1482                 */
1483                grep_attr_lock();
1484                textconv = userdiff_get_textconv(gs->driver);
1485                grep_attr_unlock();
1486        }
1487
1488        /*
1489         * We know the result of a textconv is text, so we only have to care
1490         * about binary handling if we are not using it.
1491         */
1492        if (!textconv) {
1493                switch (opt->binary) {
1494                case GREP_BINARY_DEFAULT:
1495                        if (grep_source_is_binary(gs))
1496                                binary_match_only = 1;
1497                        break;
1498                case GREP_BINARY_NOMATCH:
1499                        if (grep_source_is_binary(gs))
1500                                return 0; /* Assume unmatch */
1501                        break;
1502                case GREP_BINARY_TEXT:
1503                        break;
1504                default:
1505                        die("BUG: unknown binary handling mode");
1506                }
1507        }
1508
1509        memset(&xecfg, 0, sizeof(xecfg));
1510        opt->priv = &xecfg;
1511
1512        try_lookahead = should_lookahead(opt);
1513
1514        if (fill_textconv_grep(textconv, gs) < 0)
1515                return 0;
1516
1517        bol = gs->buf;
1518        left = gs->size;
1519        while (left) {
1520                char *eol, ch;
1521                int hit;
1522
1523                /*
1524                 * look_ahead() skips quickly to the line that possibly
1525                 * has the next hit; don't call it if we need to do
1526                 * something more than just skipping the current line
1527                 * in response to an unmatch for the current line.  E.g.
1528                 * inside a post-context window, we will show the current
1529                 * line as a context around the previous hit when it
1530                 * doesn't hit.
1531                 */
1532                if (try_lookahead
1533                    && !(last_hit
1534                         && (show_function ||
1535                             lno <= last_hit + opt->post_context))
1536                    && look_ahead(opt, &left, &lno, &bol))
1537                        break;
1538                eol = end_of_line(bol, &left);
1539                ch = *eol;
1540                *eol = 0;
1541
1542                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
1543                        ctx = GREP_CONTEXT_BODY;
1544
1545                hit = match_line(opt, bol, eol, ctx, collect_hits);
1546                *eol = ch;
1547
1548                if (collect_hits)
1549                        goto next_line;
1550
1551                /* "grep -v -e foo -e bla" should list lines
1552                 * that do not have either, so inversion should
1553                 * be done outside.
1554                 */
1555                if (opt->invert)
1556                        hit = !hit;
1557                if (opt->unmatch_name_only) {
1558                        if (hit)
1559                                return 0;
1560                        goto next_line;
1561                }
1562                if (hit) {
1563                        count++;
1564                        if (opt->status_only)
1565                                return 1;
1566                        if (opt->name_only) {
1567                                show_name(opt, gs->name);
1568                                return 1;
1569                        }
1570                        if (opt->count)
1571                                goto next_line;
1572                        if (binary_match_only) {
1573                                opt->output(opt, "Binary file ", 12);
1574                                output_color(opt, gs->name, strlen(gs->name),
1575                                             opt->color_filename);
1576                                opt->output(opt, " matches\n", 9);
1577                                return 1;
1578                        }
1579                        /* Hit at this line.  If we haven't shown the
1580                         * pre-context lines, we would need to show them.
1581                         */
1582                        if (opt->pre_context || opt->funcbody)
1583                                show_pre_context(opt, gs, bol, eol, lno);
1584                        else if (opt->funcname)
1585                                show_funcname_line(opt, gs, bol, lno);
1586                        show_line(opt, bol, eol, gs->name, lno, ':');
1587                        last_hit = lno;
1588                        if (opt->funcbody)
1589                                show_function = 1;
1590                        goto next_line;
1591                }
1592                if (show_function && (!peek_bol || peek_bol < bol)) {
1593                        unsigned long peek_left = left;
1594                        char *peek_eol = eol;
1595
1596                        /*
1597                         * Trailing empty lines are not interesting.
1598                         * Peek past them to see if they belong to the
1599                         * body of the current function.
1600                         */
1601                        peek_bol = bol;
1602                        while (is_empty_line(peek_bol, peek_eol)) {
1603                                peek_bol = peek_eol + 1;
1604                                peek_eol = end_of_line(peek_bol, &peek_left);
1605                        }
1606
1607                        if (match_funcname(opt, gs, peek_bol, peek_eol))
1608                                show_function = 0;
1609                }
1610                if (show_function ||
1611                    (last_hit && lno <= last_hit + opt->post_context)) {
1612                        /* If the last hit is within the post context,
1613                         * we need to show this line.
1614                         */
1615                        show_line(opt, bol, eol, gs->name, lno, '-');
1616                }
1617
1618        next_line:
1619                bol = eol + 1;
1620                if (!left)
1621                        break;
1622                left--;
1623                lno++;
1624        }
1625
1626        if (collect_hits)
1627                return 0;
1628
1629        if (opt->status_only)
1630                return 0;
1631        if (opt->unmatch_name_only) {
1632                /* We did not see any hit, so we want to show this */
1633                show_name(opt, gs->name);
1634                return 1;
1635        }
1636
1637        xdiff_clear_find_func(&xecfg);
1638        opt->priv = NULL;
1639
1640        /* NEEDSWORK:
1641         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
1642         * which feels mostly useless but sometimes useful.  Maybe
1643         * make it another option?  For now suppress them.
1644         */
1645        if (opt->count && count) {
1646                char buf[32];
1647                if (opt->pathname) {
1648                        output_color(opt, gs->name, strlen(gs->name),
1649                                     opt->color_filename);
1650                        output_sep(opt, ':');
1651                }
1652                xsnprintf(buf, sizeof(buf), "%u\n", count);
1653                opt->output(opt, buf, strlen(buf));
1654                return 1;
1655        }
1656        return !!last_hit;
1657}
1658
1659static void clr_hit_marker(struct grep_expr *x)
1660{
1661        /* All-hit markers are meaningful only at the very top level
1662         * OR node.
1663         */
1664        while (1) {
1665                x->hit = 0;
1666                if (x->node != GREP_NODE_OR)
1667                        return;
1668                x->u.binary.left->hit = 0;
1669                x = x->u.binary.right;
1670        }
1671}
1672
1673static int chk_hit_marker(struct grep_expr *x)
1674{
1675        /* Top level nodes have hit markers.  See if they all are hits */
1676        while (1) {
1677                if (x->node != GREP_NODE_OR)
1678                        return x->hit;
1679                if (!x->u.binary.left->hit)
1680                        return 0;
1681                x = x->u.binary.right;
1682        }
1683}
1684
1685int grep_source(struct grep_opt *opt, struct grep_source *gs)
1686{
1687        /*
1688         * we do not have to do the two-pass grep when we do not check
1689         * buffer-wide "all-match".
1690         */
1691        if (!opt->all_match)
1692                return grep_source_1(opt, gs, 0);
1693
1694        /* Otherwise the toplevel "or" terms hit a bit differently.
1695         * We first clear hit markers from them.
1696         */
1697        clr_hit_marker(opt->pattern_expression);
1698        grep_source_1(opt, gs, 1);
1699
1700        if (!chk_hit_marker(opt->pattern_expression))
1701                return 0;
1702
1703        return grep_source_1(opt, gs, 0);
1704}
1705
1706int grep_buffer(struct grep_opt *opt, char *buf, unsigned long size)
1707{
1708        struct grep_source gs;
1709        int r;
1710
1711        grep_source_init(&gs, GREP_SOURCE_BUF, NULL, NULL, NULL);
1712        gs.buf = buf;
1713        gs.size = size;
1714
1715        r = grep_source(opt, &gs);
1716
1717        grep_source_clear(&gs);
1718        return r;
1719}
1720
1721void grep_source_init(struct grep_source *gs, enum grep_source_type type,
1722                      const char *name, const char *path,
1723                      const void *identifier)
1724{
1725        gs->type = type;
1726        gs->name = xstrdup_or_null(name);
1727        gs->path = xstrdup_or_null(path);
1728        gs->buf = NULL;
1729        gs->size = 0;
1730        gs->driver = NULL;
1731
1732        switch (type) {
1733        case GREP_SOURCE_FILE:
1734                gs->identifier = xstrdup(identifier);
1735                break;
1736        case GREP_SOURCE_SUBMODULE:
1737                if (!identifier) {
1738                        gs->identifier = NULL;
1739                        break;
1740                }
1741                /*
1742                 * FALL THROUGH
1743                 * If the identifier is non-NULL (in the submodule case) it
1744                 * will be a SHA1 that needs to be copied.
1745                 */
1746        case GREP_SOURCE_SHA1:
1747                gs->identifier = xmalloc(20);
1748                hashcpy(gs->identifier, identifier);
1749                break;
1750        case GREP_SOURCE_BUF:
1751                gs->identifier = NULL;
1752                break;
1753        }
1754}
1755
1756void grep_source_clear(struct grep_source *gs)
1757{
1758        free(gs->name);
1759        gs->name = NULL;
1760        free(gs->path);
1761        gs->path = NULL;
1762        free(gs->identifier);
1763        gs->identifier = NULL;
1764        grep_source_clear_data(gs);
1765}
1766
1767void grep_source_clear_data(struct grep_source *gs)
1768{
1769        switch (gs->type) {
1770        case GREP_SOURCE_FILE:
1771        case GREP_SOURCE_SHA1:
1772        case GREP_SOURCE_SUBMODULE:
1773                free(gs->buf);
1774                gs->buf = NULL;
1775                gs->size = 0;
1776                break;
1777        case GREP_SOURCE_BUF:
1778                /* leave user-provided buf intact */
1779                break;
1780        }
1781}
1782
1783static int grep_source_load_sha1(struct grep_source *gs)
1784{
1785        enum object_type type;
1786
1787        grep_read_lock();
1788        gs->buf = read_sha1_file(gs->identifier, &type, &gs->size);
1789        grep_read_unlock();
1790
1791        if (!gs->buf)
1792                return error(_("'%s': unable to read %s"),
1793                             gs->name,
1794                             sha1_to_hex(gs->identifier));
1795        return 0;
1796}
1797
1798static int grep_source_load_file(struct grep_source *gs)
1799{
1800        const char *filename = gs->identifier;
1801        struct stat st;
1802        char *data;
1803        size_t size;
1804        int i;
1805
1806        if (lstat(filename, &st) < 0) {
1807        err_ret:
1808                if (errno != ENOENT)
1809                        error_errno(_("failed to stat '%s'"), filename);
1810                return -1;
1811        }
1812        if (!S_ISREG(st.st_mode))
1813                return -1;
1814        size = xsize_t(st.st_size);
1815        i = open(filename, O_RDONLY);
1816        if (i < 0)
1817                goto err_ret;
1818        data = xmallocz(size);
1819        if (st.st_size != read_in_full(i, data, size)) {
1820                error_errno(_("'%s': short read"), filename);
1821                close(i);
1822                free(data);
1823                return -1;
1824        }
1825        close(i);
1826
1827        gs->buf = data;
1828        gs->size = size;
1829        return 0;
1830}
1831
1832static int grep_source_load(struct grep_source *gs)
1833{
1834        if (gs->buf)
1835                return 0;
1836
1837        switch (gs->type) {
1838        case GREP_SOURCE_FILE:
1839                return grep_source_load_file(gs);
1840        case GREP_SOURCE_SHA1:
1841                return grep_source_load_sha1(gs);
1842        case GREP_SOURCE_BUF:
1843                return gs->buf ? 0 : -1;
1844        case GREP_SOURCE_SUBMODULE:
1845                break;
1846        }
1847        die("BUG: invalid grep_source type to load");
1848}
1849
1850void grep_source_load_driver(struct grep_source *gs)
1851{
1852        if (gs->driver)
1853                return;
1854
1855        grep_attr_lock();
1856        if (gs->path)
1857                gs->driver = userdiff_find_by_path(gs->path);
1858        if (!gs->driver)
1859                gs->driver = userdiff_find_by_name("default");
1860        grep_attr_unlock();
1861}
1862
1863static int grep_source_is_binary(struct grep_source *gs)
1864{
1865        grep_source_load_driver(gs);
1866        if (gs->driver->binary != -1)
1867                return gs->driver->binary;
1868
1869        if (!grep_source_load(gs))
1870                return buffer_is_binary(gs->buf, gs->size);
1871
1872        return 0;
1873}