Andrew's git / gitweb.git / grep.c
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grep.con commit Change xdl_merge to generate output even for null merges (5719db9)
   1#include "cache.h"
   2#include "grep.h"
   3#include "xdiff-interface.h"
   4
   5void append_header_grep_pattern(struct grep_opt *opt, enum grep_header_field field, const char *pat)
   6{
   7        struct grep_pat *p = xcalloc(1, sizeof(*p));
   8        p->pattern = pat;
   9        p->origin = "header";
  10        p->no = 0;
  11        p->token = GREP_PATTERN_HEAD;
  12        p->field = field;
  13        *opt->pattern_tail = p;
  14        opt->pattern_tail = &p->next;
  15        p->next = NULL;
  16}
  17
  18void append_grep_pattern(struct grep_opt *opt, const char *pat,
  19                         const char *origin, int no, enum grep_pat_token t)
  20{
  21        struct grep_pat *p = xcalloc(1, sizeof(*p));
  22        p->pattern = pat;
  23        p->origin = origin;
  24        p->no = no;
  25        p->token = t;
  26        *opt->pattern_tail = p;
  27        opt->pattern_tail = &p->next;
  28        p->next = NULL;
  29}
  30
  31static void compile_regexp(struct grep_pat *p, struct grep_opt *opt)
  32{
  33        int err = regcomp(&p->regexp, p->pattern, opt->regflags);
  34        if (err) {
  35                char errbuf[1024];
  36                char where[1024];
  37                if (p->no)
  38                        sprintf(where, "In '%s' at %d, ",
  39                                p->origin, p->no);
  40                else if (p->origin)
  41                        sprintf(where, "%s, ", p->origin);
  42                else
  43                        where[0] = 0;
  44                regerror(err, &p->regexp, errbuf, 1024);
  45                regfree(&p->regexp);
  46                die("%s'%s': %s", where, p->pattern, errbuf);
  47        }
  48}
  49
  50static struct grep_expr *compile_pattern_or(struct grep_pat **);
  51static struct grep_expr *compile_pattern_atom(struct grep_pat **list)
  52{
  53        struct grep_pat *p;
  54        struct grep_expr *x;
  55
  56        p = *list;
  57        if (!p)
  58                return NULL;
  59        switch (p->token) {
  60        case GREP_PATTERN: /* atom */
  61        case GREP_PATTERN_HEAD:
  62        case GREP_PATTERN_BODY:
  63                x = xcalloc(1, sizeof (struct grep_expr));
  64                x->node = GREP_NODE_ATOM;
  65                x->u.atom = p;
  66                *list = p->next;
  67                return x;
  68        case GREP_OPEN_PAREN:
  69                *list = p->next;
  70                x = compile_pattern_or(list);
  71                if (!*list || (*list)->token != GREP_CLOSE_PAREN)
  72                        die("unmatched parenthesis");
  73                *list = (*list)->next;
  74                return x;
  75        default:
  76                return NULL;
  77        }
  78}
  79
  80static struct grep_expr *compile_pattern_not(struct grep_pat **list)
  81{
  82        struct grep_pat *p;
  83        struct grep_expr *x;
  84
  85        p = *list;
  86        if (!p)
  87                return NULL;
  88        switch (p->token) {
  89        case GREP_NOT:
  90                if (!p->next)
  91                        die("--not not followed by pattern expression");
  92                *list = p->next;
  93                x = xcalloc(1, sizeof (struct grep_expr));
  94                x->node = GREP_NODE_NOT;
  95                x->u.unary = compile_pattern_not(list);
  96                if (!x->u.unary)
  97                        die("--not followed by non pattern expression");
  98                return x;
  99        default:
 100                return compile_pattern_atom(list);
 101        }
 102}
 103
 104static struct grep_expr *compile_pattern_and(struct grep_pat **list)
 105{
 106        struct grep_pat *p;
 107        struct grep_expr *x, *y, *z;
 108
 109        x = compile_pattern_not(list);
 110        p = *list;
 111        if (p && p->token == GREP_AND) {
 112                if (!p->next)
 113                        die("--and not followed by pattern expression");
 114                *list = p->next;
 115                y = compile_pattern_and(list);
 116                if (!y)
 117                        die("--and not followed by pattern expression");
 118                z = xcalloc(1, sizeof (struct grep_expr));
 119                z->node = GREP_NODE_AND;
 120                z->u.binary.left = x;
 121                z->u.binary.right = y;
 122                return z;
 123        }
 124        return x;
 125}
 126
 127static struct grep_expr *compile_pattern_or(struct grep_pat **list)
 128{
 129        struct grep_pat *p;
 130        struct grep_expr *x, *y, *z;
 131
 132        x = compile_pattern_and(list);
 133        p = *list;
 134        if (x && p && p->token != GREP_CLOSE_PAREN) {
 135                y = compile_pattern_or(list);
 136                if (!y)
 137                        die("not a pattern expression %s", p->pattern);
 138                z = xcalloc(1, sizeof (struct grep_expr));
 139                z->node = GREP_NODE_OR;
 140                z->u.binary.left = x;
 141                z->u.binary.right = y;
 142                return z;
 143        }
 144        return x;
 145}
 146
 147static struct grep_expr *compile_pattern_expr(struct grep_pat **list)
 148{
 149        return compile_pattern_or(list);
 150}
 151
 152void compile_grep_patterns(struct grep_opt *opt)
 153{
 154        struct grep_pat *p;
 155
 156        if (opt->all_match)
 157                opt->extended = 1;
 158
 159        for (p = opt->pattern_list; p; p = p->next) {
 160                switch (p->token) {
 161                case GREP_PATTERN: /* atom */
 162                case GREP_PATTERN_HEAD:
 163                case GREP_PATTERN_BODY:
 164                        if (!opt->fixed)
 165                                compile_regexp(p, opt);
 166                        break;
 167                default:
 168                        opt->extended = 1;
 169                        break;
 170                }
 171        }
 172
 173        if (!opt->extended)
 174                return;
 175
 176        /* Then bundle them up in an expression.
 177         * A classic recursive descent parser would do.
 178         */
 179        p = opt->pattern_list;
 180        opt->pattern_expression = compile_pattern_expr(&p);
 181        if (p)
 182                die("incomplete pattern expression: %s", p->pattern);
 183}
 184
 185static void free_pattern_expr(struct grep_expr *x)
 186{
 187        switch (x->node) {
 188        case GREP_NODE_ATOM:
 189                break;
 190        case GREP_NODE_NOT:
 191                free_pattern_expr(x->u.unary);
 192                break;
 193        case GREP_NODE_AND:
 194        case GREP_NODE_OR:
 195                free_pattern_expr(x->u.binary.left);
 196                free_pattern_expr(x->u.binary.right);
 197                break;
 198        }
 199        free(x);
 200}
 201
 202void free_grep_patterns(struct grep_opt *opt)
 203{
 204        struct grep_pat *p, *n;
 205
 206        for (p = opt->pattern_list; p; p = n) {
 207                n = p->next;
 208                switch (p->token) {
 209                case GREP_PATTERN: /* atom */
 210                case GREP_PATTERN_HEAD:
 211                case GREP_PATTERN_BODY:
 212                        regfree(&p->regexp);
 213                        break;
 214                default:
 215                        break;
 216                }
 217                free(p);
 218        }
 219
 220        if (!opt->extended)
 221                return;
 222        free_pattern_expr(opt->pattern_expression);
 223}
 224
 225static char *end_of_line(char *cp, unsigned long *left)
 226{
 227        unsigned long l = *left;
 228        while (l && *cp != '\n') {
 229                l--;
 230                cp++;
 231        }
 232        *left = l;
 233        return cp;
 234}
 235
 236static int word_char(char ch)
 237{
 238        return isalnum(ch) || ch == '_';
 239}
 240
 241static void show_line(struct grep_opt *opt, const char *bol, const char *eol,
 242                      const char *name, unsigned lno, char sign)
 243{
 244        if (opt->pathname)
 245                printf("%s%c", name, sign);
 246        if (opt->linenum)
 247                printf("%d%c", lno, sign);
 248        printf("%.*s\n", (int)(eol-bol), bol);
 249}
 250
 251static int fixmatch(const char *pattern, char *line, regmatch_t *match)
 252{
 253        char *hit = strstr(line, pattern);
 254        if (!hit) {
 255                match->rm_so = match->rm_eo = -1;
 256                return REG_NOMATCH;
 257        }
 258        else {
 259                match->rm_so = hit - line;
 260                match->rm_eo = match->rm_so + strlen(pattern);
 261                return 0;
 262        }
 263}
 264
 265static int strip_timestamp(char *bol, char **eol_p)
 266{
 267        char *eol = *eol_p;
 268        int ch;
 269
 270        while (bol < --eol) {
 271                if (*eol != '>')
 272                        continue;
 273                *eol_p = ++eol;
 274                ch = *eol;
 275                *eol = '\0';
 276                return ch;
 277        }
 278        return 0;
 279}
 280
 281static struct {
 282        const char *field;
 283        size_t len;
 284} header_field[] = {
 285        { "author ", 7 },
 286        { "committer ", 10 },
 287};
 288
 289static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol, char *eol, enum grep_context ctx)
 290{
 291        int hit = 0;
 292        int at_true_bol = 1;
 293        int saved_ch = 0;
 294        regmatch_t pmatch[10];
 295
 296        if ((p->token != GREP_PATTERN) &&
 297            ((p->token == GREP_PATTERN_HEAD) != (ctx == GREP_CONTEXT_HEAD)))
 298                return 0;
 299
 300        if (p->token == GREP_PATTERN_HEAD) {
 301                const char *field;
 302                size_t len;
 303                assert(p->field < ARRAY_SIZE(header_field));
 304                field = header_field[p->field].field;
 305                len = header_field[p->field].len;
 306                if (strncmp(bol, field, len))
 307                        return 0;
 308                bol += len;
 309                saved_ch = strip_timestamp(bol, &eol);
 310        }
 311
 312 again:
 313        if (!opt->fixed) {
 314                regex_t *exp = &p->regexp;
 315                hit = !regexec(exp, bol, ARRAY_SIZE(pmatch),
 316                               pmatch, 0);
 317        }
 318        else {
 319                hit = !fixmatch(p->pattern, bol, pmatch);
 320        }
 321
 322        if (hit && opt->word_regexp) {
 323                if ((pmatch[0].rm_so < 0) ||
 324                    (eol - bol) <= pmatch[0].rm_so ||
 325                    (pmatch[0].rm_eo < 0) ||
 326                    (eol - bol) < pmatch[0].rm_eo)
 327                        die("regexp returned nonsense");
 328
 329                /* Match beginning must be either beginning of the
 330                 * line, or at word boundary (i.e. the last char must
 331                 * not be a word char).  Similarly, match end must be
 332                 * either end of the line, or at word boundary
 333                 * (i.e. the next char must not be a word char).
 334                 */
 335                if ( ((pmatch[0].rm_so == 0 && at_true_bol) ||
 336                      !word_char(bol[pmatch[0].rm_so-1])) &&
 337                     ((pmatch[0].rm_eo == (eol-bol)) ||
 338                      !word_char(bol[pmatch[0].rm_eo])) )
 339                        ;
 340                else
 341                        hit = 0;
 342
 343                if (!hit && pmatch[0].rm_so + bol + 1 < eol) {
 344                        /* There could be more than one match on the
 345                         * line, and the first match might not be
 346                         * strict word match.  But later ones could be!
 347                         */
 348                        bol = pmatch[0].rm_so + bol + 1;
 349                        at_true_bol = 0;
 350                        goto again;
 351                }
 352        }
 353        if (p->token == GREP_PATTERN_HEAD && saved_ch)
 354                *eol = saved_ch;
 355        return hit;
 356}
 357
 358static int match_expr_eval(struct grep_opt *o,
 359                           struct grep_expr *x,
 360                           char *bol, char *eol,
 361                           enum grep_context ctx,
 362                           int collect_hits)
 363{
 364        int h = 0;
 365
 366        if (!x)
 367                die("Not a valid grep expression");
 368        switch (x->node) {
 369        case GREP_NODE_ATOM:
 370                h = match_one_pattern(o, x->u.atom, bol, eol, ctx);
 371                break;
 372        case GREP_NODE_NOT:
 373                h = !match_expr_eval(o, x->u.unary, bol, eol, ctx, 0);
 374                break;
 375        case GREP_NODE_AND:
 376                if (!collect_hits)
 377                        return (match_expr_eval(o, x->u.binary.left,
 378                                                bol, eol, ctx, 0) &&
 379                                match_expr_eval(o, x->u.binary.right,
 380                                                bol, eol, ctx, 0));
 381                h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 382                h &= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 0);
 383                break;
 384        case GREP_NODE_OR:
 385                if (!collect_hits)
 386                        return (match_expr_eval(o, x->u.binary.left,
 387                                                bol, eol, ctx, 0) ||
 388                                match_expr_eval(o, x->u.binary.right,
 389                                                bol, eol, ctx, 0));
 390                h = match_expr_eval(o, x->u.binary.left, bol, eol, ctx, 0);
 391                x->u.binary.left->hit |= h;
 392                h |= match_expr_eval(o, x->u.binary.right, bol, eol, ctx, 1);
 393                break;
 394        default:
 395                die("Unexpected node type (internal error) %d\n", x->node);
 396        }
 397        if (collect_hits)
 398                x->hit |= h;
 399        return h;
 400}
 401
 402static int match_expr(struct grep_opt *opt, char *bol, char *eol,
 403                      enum grep_context ctx, int collect_hits)
 404{
 405        struct grep_expr *x = opt->pattern_expression;
 406        return match_expr_eval(opt, x, bol, eol, ctx, collect_hits);
 407}
 408
 409static int match_line(struct grep_opt *opt, char *bol, char *eol,
 410                      enum grep_context ctx, int collect_hits)
 411{
 412        struct grep_pat *p;
 413        if (opt->extended)
 414                return match_expr(opt, bol, eol, ctx, collect_hits);
 415
 416        /* we do not call with collect_hits without being extended */
 417        for (p = opt->pattern_list; p; p = p->next) {
 418                if (match_one_pattern(opt, p, bol, eol, ctx))
 419                        return 1;
 420        }
 421        return 0;
 422}
 423
 424static int grep_buffer_1(struct grep_opt *opt, const char *name,
 425                         char *buf, unsigned long size, int collect_hits)
 426{
 427        char *bol = buf;
 428        unsigned long left = size;
 429        unsigned lno = 1;
 430        struct pre_context_line {
 431                char *bol;
 432                char *eol;
 433        } *prev = NULL, *pcl;
 434        unsigned last_hit = 0;
 435        unsigned last_shown = 0;
 436        int binary_match_only = 0;
 437        const char *hunk_mark = "";
 438        unsigned count = 0;
 439        enum grep_context ctx = GREP_CONTEXT_HEAD;
 440
 441        if (buffer_is_binary(buf, size)) {
 442                switch (opt->binary) {
 443                case GREP_BINARY_DEFAULT:
 444                        binary_match_only = 1;
 445                        break;
 446                case GREP_BINARY_NOMATCH:
 447                        return 0; /* Assume unmatch */
 448                        break;
 449                default:
 450                        break;
 451                }
 452        }
 453
 454        if (opt->pre_context)
 455                prev = xcalloc(opt->pre_context, sizeof(*prev));
 456        if (opt->pre_context || opt->post_context)
 457                hunk_mark = "--\n";
 458
 459        while (left) {
 460                char *eol, ch;
 461                int hit;
 462
 463                eol = end_of_line(bol, &left);
 464                ch = *eol;
 465                *eol = 0;
 466
 467                if ((ctx == GREP_CONTEXT_HEAD) && (eol == bol))
 468                        ctx = GREP_CONTEXT_BODY;
 469
 470                hit = match_line(opt, bol, eol, ctx, collect_hits);
 471                *eol = ch;
 472
 473                if (collect_hits)
 474                        goto next_line;
 475
 476                /* "grep -v -e foo -e bla" should list lines
 477                 * that do not have either, so inversion should
 478                 * be done outside.
 479                 */
 480                if (opt->invert)
 481                        hit = !hit;
 482                if (opt->unmatch_name_only) {
 483                        if (hit)
 484                                return 0;
 485                        goto next_line;
 486                }
 487                if (hit) {
 488                        count++;
 489                        if (opt->status_only)
 490                                return 1;
 491                        if (binary_match_only) {
 492                                printf("Binary file %s matches\n", name);
 493                                return 1;
 494                        }
 495                        if (opt->name_only) {
 496                                printf("%s\n", name);
 497                                return 1;
 498                        }
 499                        /* Hit at this line.  If we haven't shown the
 500                         * pre-context lines, we would need to show them.
 501                         * When asked to do "count", this still show
 502                         * the context which is nonsense, but the user
 503                         * deserves to get that ;-).
 504                         */
 505                        if (opt->pre_context) {
 506                                unsigned from;
 507                                if (opt->pre_context < lno)
 508                                        from = lno - opt->pre_context;
 509                                else
 510                                        from = 1;
 511                                if (from <= last_shown)
 512                                        from = last_shown + 1;
 513                                if (last_shown && from != last_shown + 1)
 514                                        fputs(hunk_mark, stdout);
 515                                while (from < lno) {
 516                                        pcl = &prev[lno-from-1];
 517                                        show_line(opt, pcl->bol, pcl->eol,
 518                                                  name, from, '-');
 519                                        from++;
 520                                }
 521                                last_shown = lno-1;
 522                        }
 523                        if (last_shown && lno != last_shown + 1)
 524                                fputs(hunk_mark, stdout);
 525                        if (!opt->count)
 526                                show_line(opt, bol, eol, name, lno, ':');
 527                        last_shown = last_hit = lno;
 528                }
 529                else if (last_hit &&
 530                         lno <= last_hit + opt->post_context) {
 531                        /* If the last hit is within the post context,
 532                         * we need to show this line.
 533                         */
 534                        if (last_shown && lno != last_shown + 1)
 535                                fputs(hunk_mark, stdout);
 536                        show_line(opt, bol, eol, name, lno, '-');
 537                        last_shown = lno;
 538                }
 539                if (opt->pre_context) {
 540                        memmove(prev+1, prev,
 541                                (opt->pre_context-1) * sizeof(*prev));
 542                        prev->bol = bol;
 543                        prev->eol = eol;
 544                }
 545
 546        next_line:
 547                bol = eol + 1;
 548                if (!left)
 549                        break;
 550                left--;
 551                lno++;
 552        }
 553
 554        free(prev);
 555        if (collect_hits)
 556                return 0;
 557
 558        if (opt->status_only)
 559                return 0;
 560        if (opt->unmatch_name_only) {
 561                /* We did not see any hit, so we want to show this */
 562                printf("%s\n", name);
 563                return 1;
 564        }
 565
 566        /* NEEDSWORK:
 567         * The real "grep -c foo *.c" gives many "bar.c:0" lines,
 568         * which feels mostly useless but sometimes useful.  Maybe
 569         * make it another option?  For now suppress them.
 570         */
 571        if (opt->count && count)
 572                printf("%s:%u\n", name, count);
 573        return !!last_hit;
 574}
 575
 576static void clr_hit_marker(struct grep_expr *x)
 577{
 578        /* All-hit markers are meaningful only at the very top level
 579         * OR node.
 580         */
 581        while (1) {
 582                x->hit = 0;
 583                if (x->node != GREP_NODE_OR)
 584                        return;
 585                x->u.binary.left->hit = 0;
 586                x = x->u.binary.right;
 587        }
 588}
 589
 590static int chk_hit_marker(struct grep_expr *x)
 591{
 592        /* Top level nodes have hit markers.  See if they all are hits */
 593        while (1) {
 594                if (x->node != GREP_NODE_OR)
 595                        return x->hit;
 596                if (!x->u.binary.left->hit)
 597                        return 0;
 598                x = x->u.binary.right;
 599        }
 600}
 601
 602int grep_buffer(struct grep_opt *opt, const char *name, char *buf, unsigned long size)
 603{
 604        /*
 605         * we do not have to do the two-pass grep when we do not check
 606         * buffer-wide "all-match".
 607         */
 608        if (!opt->all_match)
 609                return grep_buffer_1(opt, name, buf, size, 0);
 610
 611        /* Otherwise the toplevel "or" terms hit a bit differently.
 612         * We first clear hit markers from them.
 613         */
 614        clr_hit_marker(opt->pattern_expression);
 615        grep_buffer_1(opt, name, buf, size, 1);
 616
 617        if (!chk_hit_marker(opt->pattern_expression))
 618                return 0;
 619
 620        return grep_buffer_1(opt, name, buf, size, 0);
 621}