convert.con commit Merge branch 'mh/attr-macro-doc' (ac35529)
   1#include "cache.h"
   2#include "attr.h"
   3#include "run-command.h"
   4#include "quote.h"
   5#include "sigchain.h"
   6
   7/*
   8 * convert.c - convert a file when checking it out and checking it in.
   9 *
  10 * This should use the pathname to decide on whether it wants to do some
  11 * more interesting conversions (automatic gzip/unzip, general format
  12 * conversions etc etc), but by default it just does automatic CRLF<->LF
  13 * translation when the "text" attribute or "auto_crlf" option is set.
  14 */
  15
  16enum crlf_action {
  17        CRLF_GUESS = -1,
  18        CRLF_BINARY = 0,
  19        CRLF_TEXT,
  20        CRLF_INPUT,
  21        CRLF_CRLF,
  22        CRLF_AUTO
  23};
  24
  25struct text_stat {
  26        /* NUL, CR, LF and CRLF counts */
  27        unsigned nul, cr, lf, crlf;
  28
  29        /* These are just approximations! */
  30        unsigned printable, nonprintable;
  31};
  32
  33static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  34{
  35        unsigned long i;
  36
  37        memset(stats, 0, sizeof(*stats));
  38
  39        for (i = 0; i < size; i++) {
  40                unsigned char c = buf[i];
  41                if (c == '\r') {
  42                        stats->cr++;
  43                        if (i+1 < size && buf[i+1] == '\n')
  44                                stats->crlf++;
  45                        continue;
  46                }
  47                if (c == '\n') {
  48                        stats->lf++;
  49                        continue;
  50                }
  51                if (c == 127)
  52                        /* DEL */
  53                        stats->nonprintable++;
  54                else if (c < 32) {
  55                        switch (c) {
  56                                /* BS, HT, ESC and FF */
  57                        case '\b': case '\t': case '\033': case '\014':
  58                                stats->printable++;
  59                                break;
  60                        case 0:
  61                                stats->nul++;
  62                                /* fall through */
  63                        default:
  64                                stats->nonprintable++;
  65                        }
  66                }
  67                else
  68                        stats->printable++;
  69        }
  70
  71        /* If file ends with EOF then don't count this EOF as non-printable. */
  72        if (size >= 1 && buf[size-1] == '\032')
  73                stats->nonprintable--;
  74}
  75
  76/*
  77 * The same heuristics as diff.c::mmfile_is_binary()
  78 */
  79static int is_binary(unsigned long size, struct text_stat *stats)
  80{
  81
  82        if (stats->nul)
  83                return 1;
  84        if ((stats->printable >> 7) < stats->nonprintable)
  85                return 1;
  86        /*
  87         * Other heuristics? Average line length might be relevant,
  88         * as might LF vs CR vs CRLF counts..
  89         *
  90         * NOTE! It might be normal to have a low ratio of CRLF to LF
  91         * (somebody starts with a LF-only file and edits it with an editor
  92         * that adds CRLF only to lines that are added..). But do  we
  93         * want to support CR-only? Probably not.
  94         */
  95        return 0;
  96}
  97
  98static enum eol output_eol(enum crlf_action crlf_action)
  99{
 100        switch (crlf_action) {
 101        case CRLF_BINARY:
 102                return EOL_UNSET;
 103        case CRLF_CRLF:
 104                return EOL_CRLF;
 105        case CRLF_INPUT:
 106                return EOL_LF;
 107        case CRLF_GUESS:
 108                if (!auto_crlf)
 109                        return EOL_UNSET;
 110                /* fall through */
 111        case CRLF_TEXT:
 112        case CRLF_AUTO:
 113                if (auto_crlf == AUTO_CRLF_TRUE)
 114                        return EOL_CRLF;
 115                else if (auto_crlf == AUTO_CRLF_INPUT)
 116                        return EOL_LF;
 117                else if (core_eol == EOL_UNSET)
 118                        return EOL_NATIVE;
 119        }
 120        return core_eol;
 121}
 122
 123static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
 124                            struct text_stat *stats, enum safe_crlf checksafe)
 125{
 126        if (!checksafe)
 127                return;
 128
 129        if (output_eol(crlf_action) == EOL_LF) {
 130                /*
 131                 * CRLFs would not be restored by checkout:
 132                 * check if we'd remove CRLFs
 133                 */
 134                if (stats->crlf) {
 135                        if (checksafe == SAFE_CRLF_WARN)
 136                                warning("CRLF will be replaced by LF in %s.\nThe file will have its original line endings in your working directory.", path);
 137                        else /* i.e. SAFE_CRLF_FAIL */
 138                                die("CRLF would be replaced by LF in %s.", path);
 139                }
 140        } else if (output_eol(crlf_action) == EOL_CRLF) {
 141                /*
 142                 * CRLFs would be added by checkout:
 143                 * check if we have "naked" LFs
 144                 */
 145                if (stats->lf != stats->crlf) {
 146                        if (checksafe == SAFE_CRLF_WARN)
 147                                warning("LF will be replaced by CRLF in %s.\nThe file will have its original line endings in your working directory.", path);
 148                        else /* i.e. SAFE_CRLF_FAIL */
 149                                die("LF would be replaced by CRLF in %s", path);
 150                }
 151        }
 152}
 153
 154static int has_cr_in_index(const char *path)
 155{
 156        unsigned long sz;
 157        void *data;
 158        int has_cr;
 159
 160        data = read_blob_data_from_cache(path, &sz);
 161        if (!data)
 162                return 0;
 163        has_cr = memchr(data, '\r', sz) != NULL;
 164        free(data);
 165        return has_cr;
 166}
 167
 168static int crlf_to_git(const char *path, const char *src, size_t len,
 169                       struct strbuf *buf,
 170                       enum crlf_action crlf_action, enum safe_crlf checksafe)
 171{
 172        struct text_stat stats;
 173        char *dst;
 174
 175        if (crlf_action == CRLF_BINARY ||
 176            (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE) ||
 177            (src && !len))
 178                return 0;
 179
 180        /*
 181         * If we are doing a dry-run and have no source buffer, there is
 182         * nothing to analyze; we must assume we would convert.
 183         */
 184        if (!buf && !src)
 185                return 1;
 186
 187        gather_stats(src, len, &stats);
 188
 189        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 190                /*
 191                 * We're currently not going to even try to convert stuff
 192                 * that has bare CR characters. Does anybody do that crazy
 193                 * stuff?
 194                 */
 195                if (stats.cr != stats.crlf)
 196                        return 0;
 197
 198                /*
 199                 * And add some heuristics for binary vs text, of course...
 200                 */
 201                if (is_binary(len, &stats))
 202                        return 0;
 203
 204                if (crlf_action == CRLF_GUESS) {
 205                        /*
 206                         * If the file in the index has any CR in it, do not convert.
 207                         * This is the new safer autocrlf handling.
 208                         */
 209                        if (has_cr_in_index(path))
 210                                return 0;
 211                }
 212        }
 213
 214        check_safe_crlf(path, crlf_action, &stats, checksafe);
 215
 216        /* Optimization: No CR? Nothing to convert, regardless. */
 217        if (!stats.cr)
 218                return 0;
 219
 220        /*
 221         * At this point all of our source analysis is done, and we are sure we
 222         * would convert. If we are in dry-run mode, we can give an answer.
 223         */
 224        if (!buf)
 225                return 1;
 226
 227        /* only grow if not in place */
 228        if (strbuf_avail(buf) + buf->len < len)
 229                strbuf_grow(buf, len - buf->len);
 230        dst = buf->buf;
 231        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 232                /*
 233                 * If we guessed, we already know we rejected a file with
 234                 * lone CR, and we can strip a CR without looking at what
 235                 * follow it.
 236                 */
 237                do {
 238                        unsigned char c = *src++;
 239                        if (c != '\r')
 240                                *dst++ = c;
 241                } while (--len);
 242        } else {
 243                do {
 244                        unsigned char c = *src++;
 245                        if (! (c == '\r' && (1 < len && *src == '\n')))
 246                                *dst++ = c;
 247                } while (--len);
 248        }
 249        strbuf_setlen(buf, dst - buf->buf);
 250        return 1;
 251}
 252
 253static int crlf_to_worktree(const char *path, const char *src, size_t len,
 254                            struct strbuf *buf, enum crlf_action crlf_action)
 255{
 256        char *to_free = NULL;
 257        struct text_stat stats;
 258
 259        if (!len || output_eol(crlf_action) != EOL_CRLF)
 260                return 0;
 261
 262        gather_stats(src, len, &stats);
 263
 264        /* No LF? Nothing to convert, regardless. */
 265        if (!stats.lf)
 266                return 0;
 267
 268        /* Was it already in CRLF format? */
 269        if (stats.lf == stats.crlf)
 270                return 0;
 271
 272        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 273                if (crlf_action == CRLF_GUESS) {
 274                        /* If we have any CR or CRLF line endings, we do not touch it */
 275                        /* This is the new safer autocrlf-handling */
 276                        if (stats.cr > 0 || stats.crlf > 0)
 277                                return 0;
 278                }
 279
 280                /* If we have any bare CR characters, we're not going to touch it */
 281                if (stats.cr != stats.crlf)
 282                        return 0;
 283
 284                if (is_binary(len, &stats))
 285                        return 0;
 286        }
 287
 288        /* are we "faking" in place editing ? */
 289        if (src == buf->buf)
 290                to_free = strbuf_detach(buf, NULL);
 291
 292        strbuf_grow(buf, len + stats.lf - stats.crlf);
 293        for (;;) {
 294                const char *nl = memchr(src, '\n', len);
 295                if (!nl)
 296                        break;
 297                if (nl > src && nl[-1] == '\r') {
 298                        strbuf_add(buf, src, nl + 1 - src);
 299                } else {
 300                        strbuf_add(buf, src, nl - src);
 301                        strbuf_addstr(buf, "\r\n");
 302                }
 303                len -= nl + 1 - src;
 304                src  = nl + 1;
 305        }
 306        strbuf_add(buf, src, len);
 307
 308        free(to_free);
 309        return 1;
 310}
 311
 312struct filter_params {
 313        const char *src;
 314        unsigned long size;
 315        const char *cmd;
 316        const char *path;
 317};
 318
 319static int filter_buffer(int in, int out, void *data)
 320{
 321        /*
 322         * Spawn cmd and feed the buffer contents through its stdin.
 323         */
 324        struct child_process child_process;
 325        struct filter_params *params = (struct filter_params *)data;
 326        int write_err, status;
 327        const char *argv[] = { NULL, NULL };
 328
 329        /* apply % substitution to cmd */
 330        struct strbuf cmd = STRBUF_INIT;
 331        struct strbuf path = STRBUF_INIT;
 332        struct strbuf_expand_dict_entry dict[] = {
 333                { "f", NULL, },
 334                { NULL, NULL, },
 335        };
 336
 337        /* quote the path to preserve spaces, etc. */
 338        sq_quote_buf(&path, params->path);
 339        dict[0].value = path.buf;
 340
 341        /* expand all %f with the quoted path */
 342        strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 343        strbuf_release(&path);
 344
 345        argv[0] = cmd.buf;
 346
 347        memset(&child_process, 0, sizeof(child_process));
 348        child_process.argv = argv;
 349        child_process.use_shell = 1;
 350        child_process.in = -1;
 351        child_process.out = out;
 352
 353        if (start_command(&child_process))
 354                return error("cannot fork to run external filter %s", params->cmd);
 355
 356        sigchain_push(SIGPIPE, SIG_IGN);
 357
 358        write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
 359        if (close(child_process.in))
 360                write_err = 1;
 361        if (write_err)
 362                error("cannot feed the input to external filter %s", params->cmd);
 363
 364        sigchain_pop(SIGPIPE);
 365
 366        status = finish_command(&child_process);
 367        if (status)
 368                error("external filter %s failed %d", params->cmd, status);
 369
 370        strbuf_release(&cmd);
 371        return (write_err || status);
 372}
 373
 374static int apply_filter(const char *path, const char *src, size_t len,
 375                        struct strbuf *dst, const char *cmd)
 376{
 377        /*
 378         * Create a pipeline to have the command filter the buffer's
 379         * contents.
 380         *
 381         * (child --> cmd) --> us
 382         */
 383        int ret = 1;
 384        struct strbuf nbuf = STRBUF_INIT;
 385        struct async async;
 386        struct filter_params params;
 387
 388        if (!cmd)
 389                return 0;
 390
 391        if (!dst)
 392                return 1;
 393
 394        memset(&async, 0, sizeof(async));
 395        async.proc = filter_buffer;
 396        async.data = &params;
 397        async.out = -1;
 398        params.src = src;
 399        params.size = len;
 400        params.cmd = cmd;
 401        params.path = path;
 402
 403        fflush(NULL);
 404        if (start_async(&async))
 405                return 0;       /* error was already reported */
 406
 407        if (strbuf_read(&nbuf, async.out, len) < 0) {
 408                error("read from external filter %s failed", cmd);
 409                ret = 0;
 410        }
 411        if (close(async.out)) {
 412                error("read from external filter %s failed", cmd);
 413                ret = 0;
 414        }
 415        if (finish_async(&async)) {
 416                error("external filter %s failed", cmd);
 417                ret = 0;
 418        }
 419
 420        if (ret) {
 421                strbuf_swap(dst, &nbuf);
 422        }
 423        strbuf_release(&nbuf);
 424        return ret;
 425}
 426
 427static struct convert_driver {
 428        const char *name;
 429        struct convert_driver *next;
 430        const char *smudge;
 431        const char *clean;
 432        int required;
 433} *user_convert, **user_convert_tail;
 434
 435static int read_convert_config(const char *var, const char *value, void *cb)
 436{
 437        const char *key, *name;
 438        int namelen;
 439        struct convert_driver *drv;
 440
 441        /*
 442         * External conversion drivers are configured using
 443         * "filter.<name>.variable".
 444         */
 445        if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 446                return 0;
 447        for (drv = user_convert; drv; drv = drv->next)
 448                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 449                        break;
 450        if (!drv) {
 451                drv = xcalloc(1, sizeof(struct convert_driver));
 452                drv->name = xmemdupz(name, namelen);
 453                *user_convert_tail = drv;
 454                user_convert_tail = &(drv->next);
 455        }
 456
 457        /*
 458         * filter.<name>.smudge and filter.<name>.clean specifies
 459         * the command line:
 460         *
 461         *      command-line
 462         *
 463         * The command-line will not be interpolated in any way.
 464         */
 465
 466        if (!strcmp("smudge", key))
 467                return git_config_string(&drv->smudge, var, value);
 468
 469        if (!strcmp("clean", key))
 470                return git_config_string(&drv->clean, var, value);
 471
 472        if (!strcmp("required", key)) {
 473                drv->required = git_config_bool(var, value);
 474                return 0;
 475        }
 476
 477        return 0;
 478}
 479
 480static int count_ident(const char *cp, unsigned long size)
 481{
 482        /*
 483         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 484         */
 485        int cnt = 0;
 486        char ch;
 487
 488        while (size) {
 489                ch = *cp++;
 490                size--;
 491                if (ch != '$')
 492                        continue;
 493                if (size < 3)
 494                        break;
 495                if (memcmp("Id", cp, 2))
 496                        continue;
 497                ch = cp[2];
 498                cp += 3;
 499                size -= 3;
 500                if (ch == '$')
 501                        cnt++; /* $Id$ */
 502                if (ch != ':')
 503                        continue;
 504
 505                /*
 506                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 507                 */
 508                while (size) {
 509                        ch = *cp++;
 510                        size--;
 511                        if (ch == '$') {
 512                                cnt++;
 513                                break;
 514                        }
 515                        if (ch == '\n')
 516                                break;
 517                }
 518        }
 519        return cnt;
 520}
 521
 522static int ident_to_git(const char *path, const char *src, size_t len,
 523                        struct strbuf *buf, int ident)
 524{
 525        char *dst, *dollar;
 526
 527        if (!ident || (src && !count_ident(src, len)))
 528                return 0;
 529
 530        if (!buf)
 531                return 1;
 532
 533        /* only grow if not in place */
 534        if (strbuf_avail(buf) + buf->len < len)
 535                strbuf_grow(buf, len - buf->len);
 536        dst = buf->buf;
 537        for (;;) {
 538                dollar = memchr(src, '$', len);
 539                if (!dollar)
 540                        break;
 541                memmove(dst, src, dollar + 1 - src);
 542                dst += dollar + 1 - src;
 543                len -= dollar + 1 - src;
 544                src  = dollar + 1;
 545
 546                if (len > 3 && !memcmp(src, "Id:", 3)) {
 547                        dollar = memchr(src + 3, '$', len - 3);
 548                        if (!dollar)
 549                                break;
 550                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 551                                /* Line break before the next dollar. */
 552                                continue;
 553                        }
 554
 555                        memcpy(dst, "Id$", 3);
 556                        dst += 3;
 557                        len -= dollar + 1 - src;
 558                        src  = dollar + 1;
 559                }
 560        }
 561        memmove(dst, src, len);
 562        strbuf_setlen(buf, dst + len - buf->buf);
 563        return 1;
 564}
 565
 566static int ident_to_worktree(const char *path, const char *src, size_t len,
 567                             struct strbuf *buf, int ident)
 568{
 569        unsigned char sha1[20];
 570        char *to_free = NULL, *dollar, *spc;
 571        int cnt;
 572
 573        if (!ident)
 574                return 0;
 575
 576        cnt = count_ident(src, len);
 577        if (!cnt)
 578                return 0;
 579
 580        /* are we "faking" in place editing ? */
 581        if (src == buf->buf)
 582                to_free = strbuf_detach(buf, NULL);
 583        hash_sha1_file(src, len, "blob", sha1);
 584
 585        strbuf_grow(buf, len + cnt * 43);
 586        for (;;) {
 587                /* step 1: run to the next '$' */
 588                dollar = memchr(src, '$', len);
 589                if (!dollar)
 590                        break;
 591                strbuf_add(buf, src, dollar + 1 - src);
 592                len -= dollar + 1 - src;
 593                src  = dollar + 1;
 594
 595                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 596                if (len < 3 || memcmp("Id", src, 2))
 597                        continue;
 598
 599                /* step 3: skip over Id$ or Id:xxxxx$ */
 600                if (src[2] == '$') {
 601                        src += 3;
 602                        len -= 3;
 603                } else if (src[2] == ':') {
 604                        /*
 605                         * It's possible that an expanded Id has crept its way into the
 606                         * repository, we cope with that by stripping the expansion out.
 607                         * This is probably not a good idea, since it will cause changes
 608                         * on checkout, which won't go away by stash, but let's keep it
 609                         * for git-style ids.
 610                         */
 611                        dollar = memchr(src + 3, '$', len - 3);
 612                        if (!dollar) {
 613                                /* incomplete keyword, no more '$', so just quit the loop */
 614                                break;
 615                        }
 616
 617                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 618                                /* Line break before the next dollar. */
 619                                continue;
 620                        }
 621
 622                        spc = memchr(src + 4, ' ', dollar - src - 4);
 623                        if (spc && spc < dollar-1) {
 624                                /* There are spaces in unexpected places.
 625                                 * This is probably an id from some other
 626                                 * versioning system. Keep it for now.
 627                                 */
 628                                continue;
 629                        }
 630
 631                        len -= dollar + 1 - src;
 632                        src  = dollar + 1;
 633                } else {
 634                        /* it wasn't a "Id$" or "Id:xxxx$" */
 635                        continue;
 636                }
 637
 638                /* step 4: substitute */
 639                strbuf_addstr(buf, "Id: ");
 640                strbuf_add(buf, sha1_to_hex(sha1), 40);
 641                strbuf_addstr(buf, " $");
 642        }
 643        strbuf_add(buf, src, len);
 644
 645        free(to_free);
 646        return 1;
 647}
 648
 649static enum crlf_action git_path_check_crlf(const char *path, struct git_attr_check *check)
 650{
 651        const char *value = check->value;
 652
 653        if (ATTR_TRUE(value))
 654                return CRLF_TEXT;
 655        else if (ATTR_FALSE(value))
 656                return CRLF_BINARY;
 657        else if (ATTR_UNSET(value))
 658                ;
 659        else if (!strcmp(value, "input"))
 660                return CRLF_INPUT;
 661        else if (!strcmp(value, "auto"))
 662                return CRLF_AUTO;
 663        return CRLF_GUESS;
 664}
 665
 666static enum eol git_path_check_eol(const char *path, struct git_attr_check *check)
 667{
 668        const char *value = check->value;
 669
 670        if (ATTR_UNSET(value))
 671                ;
 672        else if (!strcmp(value, "lf"))
 673                return EOL_LF;
 674        else if (!strcmp(value, "crlf"))
 675                return EOL_CRLF;
 676        return EOL_UNSET;
 677}
 678
 679static struct convert_driver *git_path_check_convert(const char *path,
 680                                             struct git_attr_check *check)
 681{
 682        const char *value = check->value;
 683        struct convert_driver *drv;
 684
 685        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 686                return NULL;
 687        for (drv = user_convert; drv; drv = drv->next)
 688                if (!strcmp(value, drv->name))
 689                        return drv;
 690        return NULL;
 691}
 692
 693static int git_path_check_ident(const char *path, struct git_attr_check *check)
 694{
 695        const char *value = check->value;
 696
 697        return !!ATTR_TRUE(value);
 698}
 699
 700static enum crlf_action input_crlf_action(enum crlf_action text_attr, enum eol eol_attr)
 701{
 702        if (text_attr == CRLF_BINARY)
 703                return CRLF_BINARY;
 704        if (eol_attr == EOL_LF)
 705                return CRLF_INPUT;
 706        if (eol_attr == EOL_CRLF)
 707                return CRLF_CRLF;
 708        return text_attr;
 709}
 710
 711struct conv_attrs {
 712        struct convert_driver *drv;
 713        enum crlf_action crlf_action;
 714        enum eol eol_attr;
 715        int ident;
 716};
 717
 718static const char *conv_attr_name[] = {
 719        "crlf", "ident", "filter", "eol", "text",
 720};
 721#define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 722
 723static void convert_attrs(struct conv_attrs *ca, const char *path)
 724{
 725        int i;
 726        static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 727
 728        if (!ccheck[0].attr) {
 729                for (i = 0; i < NUM_CONV_ATTRS; i++)
 730                        ccheck[i].attr = git_attr(conv_attr_name[i]);
 731                user_convert_tail = &user_convert;
 732                git_config(read_convert_config, NULL);
 733        }
 734
 735        if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 736                ca->crlf_action = git_path_check_crlf(path, ccheck + 4);
 737                if (ca->crlf_action == CRLF_GUESS)
 738                        ca->crlf_action = git_path_check_crlf(path, ccheck + 0);
 739                ca->ident = git_path_check_ident(path, ccheck + 1);
 740                ca->drv = git_path_check_convert(path, ccheck + 2);
 741                ca->eol_attr = git_path_check_eol(path, ccheck + 3);
 742        } else {
 743                ca->drv = NULL;
 744                ca->crlf_action = CRLF_GUESS;
 745                ca->eol_attr = EOL_UNSET;
 746                ca->ident = 0;
 747        }
 748}
 749
 750int convert_to_git(const char *path, const char *src, size_t len,
 751                   struct strbuf *dst, enum safe_crlf checksafe)
 752{
 753        int ret = 0;
 754        const char *filter = NULL;
 755        int required = 0;
 756        struct conv_attrs ca;
 757
 758        convert_attrs(&ca, path);
 759        if (ca.drv) {
 760                filter = ca.drv->clean;
 761                required = ca.drv->required;
 762        }
 763
 764        ret |= apply_filter(path, src, len, dst, filter);
 765        if (!ret && required)
 766                die("%s: clean filter '%s' failed", path, ca.drv->name);
 767
 768        if (ret && dst) {
 769                src = dst->buf;
 770                len = dst->len;
 771        }
 772        ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 773        ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 774        if (ret && dst) {
 775                src = dst->buf;
 776                len = dst->len;
 777        }
 778        return ret | ident_to_git(path, src, len, dst, ca.ident);
 779}
 780
 781static int convert_to_working_tree_internal(const char *path, const char *src,
 782                                            size_t len, struct strbuf *dst,
 783                                            int normalizing)
 784{
 785        int ret = 0, ret_filter = 0;
 786        const char *filter = NULL;
 787        int required = 0;
 788        struct conv_attrs ca;
 789
 790        convert_attrs(&ca, path);
 791        if (ca.drv) {
 792                filter = ca.drv->smudge;
 793                required = ca.drv->required;
 794        }
 795
 796        ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 797        if (ret) {
 798                src = dst->buf;
 799                len = dst->len;
 800        }
 801        /*
 802         * CRLF conversion can be skipped if normalizing, unless there
 803         * is a smudge filter.  The filter might expect CRLFs.
 804         */
 805        if (filter || !normalizing) {
 806                ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 807                ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 808                if (ret) {
 809                        src = dst->buf;
 810                        len = dst->len;
 811                }
 812        }
 813
 814        ret_filter = apply_filter(path, src, len, dst, filter);
 815        if (!ret_filter && required)
 816                die("%s: smudge filter %s failed", path, ca.drv->name);
 817
 818        return ret | ret_filter;
 819}
 820
 821int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 822{
 823        return convert_to_working_tree_internal(path, src, len, dst, 0);
 824}
 825
 826int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 827{
 828        int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 829        if (ret) {
 830                src = dst->buf;
 831                len = dst->len;
 832        }
 833        return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
 834}
 835
 836/*****************************************************************
 837 *
 838 * Streaming conversion support
 839 *
 840 *****************************************************************/
 841
 842typedef int (*filter_fn)(struct stream_filter *,
 843                         const char *input, size_t *isize_p,
 844                         char *output, size_t *osize_p);
 845typedef void (*free_fn)(struct stream_filter *);
 846
 847struct stream_filter_vtbl {
 848        filter_fn filter;
 849        free_fn free;
 850};
 851
 852struct stream_filter {
 853        struct stream_filter_vtbl *vtbl;
 854};
 855
 856static int null_filter_fn(struct stream_filter *filter,
 857                          const char *input, size_t *isize_p,
 858                          char *output, size_t *osize_p)
 859{
 860        size_t count;
 861
 862        if (!input)
 863                return 0; /* we do not keep any states */
 864        count = *isize_p;
 865        if (*osize_p < count)
 866                count = *osize_p;
 867        if (count) {
 868                memmove(output, input, count);
 869                *isize_p -= count;
 870                *osize_p -= count;
 871        }
 872        return 0;
 873}
 874
 875static void null_free_fn(struct stream_filter *filter)
 876{
 877        ; /* nothing -- null instances are shared */
 878}
 879
 880static struct stream_filter_vtbl null_vtbl = {
 881        null_filter_fn,
 882        null_free_fn,
 883};
 884
 885static struct stream_filter null_filter_singleton = {
 886        &null_vtbl,
 887};
 888
 889int is_null_stream_filter(struct stream_filter *filter)
 890{
 891        return filter == &null_filter_singleton;
 892}
 893
 894
 895/*
 896 * LF-to-CRLF filter
 897 */
 898
 899struct lf_to_crlf_filter {
 900        struct stream_filter filter;
 901        unsigned has_held:1;
 902        char held;
 903};
 904
 905static int lf_to_crlf_filter_fn(struct stream_filter *filter,
 906                                const char *input, size_t *isize_p,
 907                                char *output, size_t *osize_p)
 908{
 909        size_t count, o = 0;
 910        struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
 911
 912        /*
 913         * We may be holding onto the CR to see if it is followed by a
 914         * LF, in which case we would need to go to the main loop.
 915         * Otherwise, just emit it to the output stream.
 916         */
 917        if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
 918                output[o++] = lf_to_crlf->held;
 919                lf_to_crlf->has_held = 0;
 920        }
 921
 922        /* We are told to drain */
 923        if (!input) {
 924                *osize_p -= o;
 925                return 0;
 926        }
 927
 928        count = *isize_p;
 929        if (count || lf_to_crlf->has_held) {
 930                size_t i;
 931                int was_cr = 0;
 932
 933                if (lf_to_crlf->has_held) {
 934                        was_cr = 1;
 935                        lf_to_crlf->has_held = 0;
 936                }
 937
 938                for (i = 0; o < *osize_p && i < count; i++) {
 939                        char ch = input[i];
 940
 941                        if (ch == '\n') {
 942                                output[o++] = '\r';
 943                        } else if (was_cr) {
 944                                /*
 945                                 * Previous round saw CR and it is not followed
 946                                 * by a LF; emit the CR before processing the
 947                                 * current character.
 948                                 */
 949                                output[o++] = '\r';
 950                        }
 951
 952                        /*
 953                         * We may have consumed the last output slot,
 954                         * in which case we need to break out of this
 955                         * loop; hold the current character before
 956                         * returning.
 957                         */
 958                        if (*osize_p <= o) {
 959                                lf_to_crlf->has_held = 1;
 960                                lf_to_crlf->held = ch;
 961                                continue; /* break but increment i */
 962                        }
 963
 964                        if (ch == '\r') {
 965                                was_cr = 1;
 966                                continue;
 967                        }
 968
 969                        was_cr = 0;
 970                        output[o++] = ch;
 971                }
 972
 973                *osize_p -= o;
 974                *isize_p -= i;
 975
 976                if (!lf_to_crlf->has_held && was_cr) {
 977                        lf_to_crlf->has_held = 1;
 978                        lf_to_crlf->held = '\r';
 979                }
 980        }
 981        return 0;
 982}
 983
 984static void lf_to_crlf_free_fn(struct stream_filter *filter)
 985{
 986        free(filter);
 987}
 988
 989static struct stream_filter_vtbl lf_to_crlf_vtbl = {
 990        lf_to_crlf_filter_fn,
 991        lf_to_crlf_free_fn,
 992};
 993
 994static struct stream_filter *lf_to_crlf_filter(void)
 995{
 996        struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
 997
 998        lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
 999        return (struct stream_filter *)lf_to_crlf;
1000}
1001
1002/*
1003 * Cascade filter
1004 */
1005#define FILTER_BUFFER 1024
1006struct cascade_filter {
1007        struct stream_filter filter;
1008        struct stream_filter *one;
1009        struct stream_filter *two;
1010        char buf[FILTER_BUFFER];
1011        int end, ptr;
1012};
1013
1014static int cascade_filter_fn(struct stream_filter *filter,
1015                             const char *input, size_t *isize_p,
1016                             char *output, size_t *osize_p)
1017{
1018        struct cascade_filter *cas = (struct cascade_filter *) filter;
1019        size_t filled = 0;
1020        size_t sz = *osize_p;
1021        size_t to_feed, remaining;
1022
1023        /*
1024         * input -- (one) --> buf -- (two) --> output
1025         */
1026        while (filled < sz) {
1027                remaining = sz - filled;
1028
1029                /* do we already have something to feed two with? */
1030                if (cas->ptr < cas->end) {
1031                        to_feed = cas->end - cas->ptr;
1032                        if (stream_filter(cas->two,
1033                                          cas->buf + cas->ptr, &to_feed,
1034                                          output + filled, &remaining))
1035                                return -1;
1036                        cas->ptr += (cas->end - cas->ptr) - to_feed;
1037                        filled = sz - remaining;
1038                        continue;
1039                }
1040
1041                /* feed one from upstream and have it emit into our buffer */
1042                to_feed = input ? *isize_p : 0;
1043                if (input && !to_feed)
1044                        break;
1045                remaining = sizeof(cas->buf);
1046                if (stream_filter(cas->one,
1047                                  input, &to_feed,
1048                                  cas->buf, &remaining))
1049                        return -1;
1050                cas->end = sizeof(cas->buf) - remaining;
1051                cas->ptr = 0;
1052                if (input) {
1053                        size_t fed = *isize_p - to_feed;
1054                        *isize_p -= fed;
1055                        input += fed;
1056                }
1057
1058                /* do we know that we drained one completely? */
1059                if (input || cas->end)
1060                        continue;
1061
1062                /* tell two to drain; we have nothing more to give it */
1063                to_feed = 0;
1064                remaining = sz - filled;
1065                if (stream_filter(cas->two,
1066                                  NULL, &to_feed,
1067                                  output + filled, &remaining))
1068                        return -1;
1069                if (remaining == (sz - filled))
1070                        break; /* completely drained two */
1071                filled = sz - remaining;
1072        }
1073        *osize_p -= filled;
1074        return 0;
1075}
1076
1077static void cascade_free_fn(struct stream_filter *filter)
1078{
1079        struct cascade_filter *cas = (struct cascade_filter *)filter;
1080        free_stream_filter(cas->one);
1081        free_stream_filter(cas->two);
1082        free(filter);
1083}
1084
1085static struct stream_filter_vtbl cascade_vtbl = {
1086        cascade_filter_fn,
1087        cascade_free_fn,
1088};
1089
1090static struct stream_filter *cascade_filter(struct stream_filter *one,
1091                                            struct stream_filter *two)
1092{
1093        struct cascade_filter *cascade;
1094
1095        if (!one || is_null_stream_filter(one))
1096                return two;
1097        if (!two || is_null_stream_filter(two))
1098                return one;
1099
1100        cascade = xmalloc(sizeof(*cascade));
1101        cascade->one = one;
1102        cascade->two = two;
1103        cascade->end = cascade->ptr = 0;
1104        cascade->filter.vtbl = &cascade_vtbl;
1105        return (struct stream_filter *)cascade;
1106}
1107
1108/*
1109 * ident filter
1110 */
1111#define IDENT_DRAINING (-1)
1112#define IDENT_SKIPPING (-2)
1113struct ident_filter {
1114        struct stream_filter filter;
1115        struct strbuf left;
1116        int state;
1117        char ident[45]; /* ": x40 $" */
1118};
1119
1120static int is_foreign_ident(const char *str)
1121{
1122        int i;
1123
1124        if (!starts_with(str, "$Id: "))
1125                return 0;
1126        for (i = 5; str[i]; i++) {
1127                if (isspace(str[i]) && str[i+1] != '$')
1128                        return 1;
1129        }
1130        return 0;
1131}
1132
1133static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1134{
1135        size_t to_drain = ident->left.len;
1136
1137        if (*osize_p < to_drain)
1138                to_drain = *osize_p;
1139        if (to_drain) {
1140                memcpy(*output_p, ident->left.buf, to_drain);
1141                strbuf_remove(&ident->left, 0, to_drain);
1142                *output_p += to_drain;
1143                *osize_p -= to_drain;
1144        }
1145        if (!ident->left.len)
1146                ident->state = 0;
1147}
1148
1149static int ident_filter_fn(struct stream_filter *filter,
1150                           const char *input, size_t *isize_p,
1151                           char *output, size_t *osize_p)
1152{
1153        struct ident_filter *ident = (struct ident_filter *)filter;
1154        static const char head[] = "$Id";
1155
1156        if (!input) {
1157                /* drain upon eof */
1158                switch (ident->state) {
1159                default:
1160                        strbuf_add(&ident->left, head, ident->state);
1161                case IDENT_SKIPPING:
1162                        /* fallthru */
1163                case IDENT_DRAINING:
1164                        ident_drain(ident, &output, osize_p);
1165                }
1166                return 0;
1167        }
1168
1169        while (*isize_p || (ident->state == IDENT_DRAINING)) {
1170                int ch;
1171
1172                if (ident->state == IDENT_DRAINING) {
1173                        ident_drain(ident, &output, osize_p);
1174                        if (!*osize_p)
1175                                break;
1176                        continue;
1177                }
1178
1179                ch = *(input++);
1180                (*isize_p)--;
1181
1182                if (ident->state == IDENT_SKIPPING) {
1183                        /*
1184                         * Skipping until '$' or LF, but keeping them
1185                         * in case it is a foreign ident.
1186                         */
1187                        strbuf_addch(&ident->left, ch);
1188                        if (ch != '\n' && ch != '$')
1189                                continue;
1190                        if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1191                                strbuf_setlen(&ident->left, sizeof(head) - 1);
1192                                strbuf_addstr(&ident->left, ident->ident);
1193                        }
1194                        ident->state = IDENT_DRAINING;
1195                        continue;
1196                }
1197
1198                if (ident->state < sizeof(head) &&
1199                    head[ident->state] == ch) {
1200                        ident->state++;
1201                        continue;
1202                }
1203
1204                if (ident->state)
1205                        strbuf_add(&ident->left, head, ident->state);
1206                if (ident->state == sizeof(head) - 1) {
1207                        if (ch != ':' && ch != '$') {
1208                                strbuf_addch(&ident->left, ch);
1209                                ident->state = 0;
1210                                continue;
1211                        }
1212
1213                        if (ch == ':') {
1214                                strbuf_addch(&ident->left, ch);
1215                                ident->state = IDENT_SKIPPING;
1216                        } else {
1217                                strbuf_addstr(&ident->left, ident->ident);
1218                                ident->state = IDENT_DRAINING;
1219                        }
1220                        continue;
1221                }
1222
1223                strbuf_addch(&ident->left, ch);
1224                ident->state = IDENT_DRAINING;
1225        }
1226        return 0;
1227}
1228
1229static void ident_free_fn(struct stream_filter *filter)
1230{
1231        struct ident_filter *ident = (struct ident_filter *)filter;
1232        strbuf_release(&ident->left);
1233        free(filter);
1234}
1235
1236static struct stream_filter_vtbl ident_vtbl = {
1237        ident_filter_fn,
1238        ident_free_fn,
1239};
1240
1241static struct stream_filter *ident_filter(const unsigned char *sha1)
1242{
1243        struct ident_filter *ident = xmalloc(sizeof(*ident));
1244
1245        sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
1246        strbuf_init(&ident->left, 0);
1247        ident->filter.vtbl = &ident_vtbl;
1248        ident->state = 0;
1249        return (struct stream_filter *)ident;
1250}
1251
1252/*
1253 * Return an appropriately constructed filter for the path, or NULL if
1254 * the contents cannot be filtered without reading the whole thing
1255 * in-core.
1256 *
1257 * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1258 * large binary blob you would want us not to slurp into the memory!
1259 */
1260struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1261{
1262        struct conv_attrs ca;
1263        enum crlf_action crlf_action;
1264        struct stream_filter *filter = NULL;
1265
1266        convert_attrs(&ca, path);
1267
1268        if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1269                return filter;
1270
1271        if (ca.ident)
1272                filter = ident_filter(sha1);
1273
1274        crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
1275
1276        if ((crlf_action == CRLF_BINARY) || (crlf_action == CRLF_INPUT) ||
1277            (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
1278                filter = cascade_filter(filter, &null_filter_singleton);
1279
1280        else if (output_eol(crlf_action) == EOL_CRLF &&
1281                 !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
1282                filter = cascade_filter(filter, lf_to_crlf_filter());
1283
1284        return filter;
1285}
1286
1287void free_stream_filter(struct stream_filter *filter)
1288{
1289        filter->vtbl->free(filter);
1290}
1291
1292int stream_filter(struct stream_filter *filter,
1293                  const char *input, size_t *isize_p,
1294                  char *output, size_t *osize_p)
1295{
1296        return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1297}