convert.c

   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
  16 enum crlf_action {
  17         CRLF_GUESS = -1,
  18         CRLF_BINARY = 0,
  19         CRLF_TEXT,
  20         CRLF_INPUT,
  21         CRLF_CRLF,
  22         CRLF_AUTO
  23 };
  24
  25 struct 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
  33 static 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  */
  79 static 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
  98 static 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
 123 static 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
 154 static int has_cr_in_index(const char *path)
 155 {
 156         int pos, len;
 157         unsigned long sz;
 158         enum object_type type;
 159         void *data;
 160         int has_cr;
 161         struct index_state *istate = &the_index;
 162
 163         len = strlen(path);
 164         pos = index_name_pos(istate, path, len);
 165         if (pos < 0) {
 166                 /*
 167                  * We might be in the middle of a merge, in which
 168                  * case we would read stage #2 (ours).
 169                  */
 170                 int i;
 171                 for (i = -pos - 1;
 172                      (pos < 0 && i < istate->cache_nr &&
 173                       !strcmp(istate->cache[i]->name, path));
 174                      i++)
 175                         if (ce_stage(istate->cache[i]) == 2)
 176                                 pos = i;
 177         }
 178         if (pos < 0)
 179                 return 0;
 180         data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
 181         if (!data || type != OBJ_BLOB) {
 182                 free(data);
 183                 return 0;
 184         }
 185
 186         has_cr = memchr(data, '\r', sz) != NULL;
 187         free(data);
 188         return has_cr;
 189 }
 190
 191 static int crlf_to_git(const char *path, const char *src, size_t len,
 192                        struct strbuf *buf,
 193                        enum crlf_action crlf_action, enum safe_crlf checksafe)
 194 {
 195         struct text_stat stats;
 196         char *dst;
 197
 198         if (crlf_action == CRLF_BINARY ||
 199             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE) ||
 200             (src && !len))
 201                 return 0;
 202
 203         /*
 204          * If we are doing a dry-run and have no source buffer, there is
 205          * nothing to analyze; we must assume we would convert.
 206          */
 207         if (!buf && !src)
 208                 return 1;
 209
 210         gather_stats(src, len, &stats);
 211
 212         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 213                 /*
 214                  * We're currently not going to even try to convert stuff
 215                  * that has bare CR characters. Does anybody do that crazy
 216                  * stuff?
 217                  */
 218                 if (stats.cr != stats.crlf)
 219                         return 0;
 220
 221                 /*
 222                  * And add some heuristics for binary vs text, of course...
 223                  */
 224                 if (is_binary(len, &stats))
 225                         return 0;
 226
 227                 if (crlf_action == CRLF_GUESS) {
 228                         /*
 229                          * If the file in the index has any CR in it, do not convert.
 230                          * This is the new safer autocrlf handling.
 231                          */
 232                         if (has_cr_in_index(path))
 233                                 return 0;
 234                 }
 235         }
 236
 237         check_safe_crlf(path, crlf_action, &stats, checksafe);
 238
 239         /* Optimization: No CR? Nothing to convert, regardless. */
 240         if (!stats.cr)
 241                 return 0;
 242
 243         /*
 244          * At this point all of our source analysis is done, and we are sure we
 245          * would convert. If we are in dry-run mode, we can give an answer.
 246          */
 247         if (!buf)
 248                 return 1;
 249
 250         /* only grow if not in place */
 251         if (strbuf_avail(buf) + buf->len < len)
 252                 strbuf_grow(buf, len - buf->len);
 253         dst = buf->buf;
 254         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 255                 /*
 256                  * If we guessed, we already know we rejected a file with
 257                  * lone CR, and we can strip a CR without looking at what
 258                  * follow it.
 259                  */
 260                 do {
 261                         unsigned char c = *src++;
 262                         if (c != '\r')
 263                                 *dst++ = c;
 264                 } while (--len);
 265         } else {
 266                 do {
 267                         unsigned char c = *src++;
 268                         if (! (c == '\r' && (1 < len && *src == '\n')))
 269                                 *dst++ = c;
 270                 } while (--len);
 271         }
 272         strbuf_setlen(buf, dst - buf->buf);
 273         return 1;
 274 }
 275
 276 static int crlf_to_worktree(const char *path, const char *src, size_t len,
 277                             struct strbuf *buf, enum crlf_action crlf_action)
 278 {
 279         char *to_free = NULL;
 280         struct text_stat stats;
 281
 282         if (!len || output_eol(crlf_action) != EOL_CRLF)
 283                 return 0;
 284
 285         gather_stats(src, len, &stats);
 286
 287         /* No LF? Nothing to convert, regardless. */
 288         if (!stats.lf)
 289                 return 0;
 290
 291         /* Was it already in CRLF format? */
 292         if (stats.lf == stats.crlf)
 293                 return 0;
 294
 295         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 296                 if (crlf_action == CRLF_GUESS) {
 297                         /* If we have any CR or CRLF line endings, we do not touch it */
 298                         /* This is the new safer autocrlf-handling */
 299                         if (stats.cr > 0 || stats.crlf > 0)
 300                                 return 0;
 301                 }
 302
 303                 /* If we have any bare CR characters, we're not going to touch it */
 304                 if (stats.cr != stats.crlf)
 305                         return 0;
 306
 307                 if (is_binary(len, &stats))
 308                         return 0;
 309         }
 310
 311         /* are we "faking" in place editing ? */
 312         if (src == buf->buf)
 313                 to_free = strbuf_detach(buf, NULL);
 314
 315         strbuf_grow(buf, len + stats.lf - stats.crlf);
 316         for (;;) {
 317                 const char *nl = memchr(src, '\n', len);
 318                 if (!nl)
 319                         break;
 320                 if (nl > src && nl[-1] == '\r') {
 321                         strbuf_add(buf, src, nl + 1 - src);
 322                 } else {
 323                         strbuf_add(buf, src, nl - src);
 324                         strbuf_addstr(buf, "\r\n");
 325                 }
 326                 len -= nl + 1 - src;
 327                 src  = nl + 1;
 328         }
 329         strbuf_add(buf, src, len);
 330
 331         free(to_free);
 332         return 1;
 333 }
 334
 335 struct filter_params {
 336         const char *src;
 337         unsigned long size;
 338         const char *cmd;
 339         const char *path;
 340 };
 341
 342 static int filter_buffer(int in, int out, void *data)
 343 {
 344         /*
 345          * Spawn cmd and feed the buffer contents through its stdin.
 346          */
 347         struct child_process child_process;
 348         struct filter_params *params = (struct filter_params *)data;
 349         int write_err, status;
 350         const char *argv[] = { NULL, NULL };
 351
 352         /* apply % substitution to cmd */
 353         struct strbuf cmd = STRBUF_INIT;
 354         struct strbuf path = STRBUF_INIT;
 355         struct strbuf_expand_dict_entry dict[] = {
 356                 { "f", NULL, },
 357                 { NULL, NULL, },
 358         };
 359
 360         /* quote the path to preserve spaces, etc. */
 361         sq_quote_buf(&path, params->path);
 362         dict[0].value = path.buf;
 363
 364         /* expand all %f with the quoted path */
 365         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 366         strbuf_release(&path);
 367
 368         argv[0] = cmd.buf;
 369
 370         memset(&child_process, 0, sizeof(child_process));
 371         child_process.argv = argv;
 372         child_process.use_shell = 1;
 373         child_process.in = -1;
 374         child_process.out = out;
 375
 376         if (start_command(&child_process))
 377                 return error("cannot fork to run external filter %s", params->cmd);
 378
 379         sigchain_push(SIGPIPE, SIG_IGN);
 380
 381         write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
 382         if (close(child_process.in))
 383                 write_err = 1;
 384         if (write_err)
 385                 error("cannot feed the input to external filter %s", params->cmd);
 386
 387         sigchain_pop(SIGPIPE);
 388
 389         status = finish_command(&child_process);
 390         if (status)
 391                 error("external filter %s failed %d", params->cmd, status);
 392
 393         strbuf_release(&cmd);
 394         return (write_err || status);
 395 }
 396
 397 static int apply_filter(const char *path, const char *src, size_t len,
 398                         struct strbuf *dst, const char *cmd)
 399 {
 400         /*
 401          * Create a pipeline to have the command filter the buffer's
 402          * contents.
 403          *
 404          * (child --> cmd) --> us
 405          */
 406         int ret = 1;
 407         struct strbuf nbuf = STRBUF_INIT;
 408         struct async async;
 409         struct filter_params params;
 410
 411         if (!cmd)
 412                 return 0;
 413
 414         if (!dst)
 415                 return 1;
 416
 417         memset(&async, 0, sizeof(async));
 418         async.proc = filter_buffer;
 419         async.data = &params;
 420         async.out = -1;
 421         params.src = src;
 422         params.size = len;
 423         params.cmd = cmd;
 424         params.path = path;
 425
 426         fflush(NULL);
 427         if (start_async(&async))
 428                 return 0;       /* error was already reported */
 429
 430         if (strbuf_read(&nbuf, async.out, len) < 0) {
 431                 error("read from external filter %s failed", cmd);
 432                 ret = 0;
 433         }
 434         if (close(async.out)) {
 435                 error("read from external filter %s failed", cmd);
 436                 ret = 0;
 437         }
 438         if (finish_async(&async)) {
 439                 error("external filter %s failed", cmd);
 440                 ret = 0;
 441         }
 442
 443         if (ret) {
 444                 strbuf_swap(dst, &nbuf);
 445         }
 446         strbuf_release(&nbuf);
 447         return ret;
 448 }
 449
 450 static struct convert_driver {
 451         const char *name;
 452         struct convert_driver *next;
 453         const char *smudge;
 454         const char *clean;
 455         int required;
 456 } *user_convert, **user_convert_tail;
 457
 458 static int read_convert_config(const char *var, const char *value, void *cb)
 459 {
 460         const char *key, *name;
 461         int namelen;
 462         struct convert_driver *drv;
 463
 464         /*
 465          * External conversion drivers are configured using
 466          * "filter.<name>.variable".
 467          */
 468         if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 469                 return 0;
 470         for (drv = user_convert; drv; drv = drv->next)
 471                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 472                         break;
 473         if (!drv) {
 474                 drv = xcalloc(1, sizeof(struct convert_driver));
 475                 drv->name = xmemdupz(name, namelen);
 476                 *user_convert_tail = drv;
 477                 user_convert_tail = &(drv->next);
 478         }
 479
 480         /*
 481          * filter.<name>.smudge and filter.<name>.clean specifies
 482          * the command line:
 483          *
 484          *      command-line
 485          *
 486          * The command-line will not be interpolated in any way.
 487          */
 488
 489         if (!strcmp("smudge", key))
 490                 return git_config_string(&drv->smudge, var, value);
 491
 492         if (!strcmp("clean", key))
 493                 return git_config_string(&drv->clean, var, value);
 494
 495         if (!strcmp("required", key)) {
 496                 drv->required = git_config_bool(var, value);
 497                 return 0;
 498         }
 499
 500         return 0;
 501 }
 502
 503 static int count_ident(const char *cp, unsigned long size)
 504 {
 505         /*
 506          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 507          */
 508         int cnt = 0;
 509         char ch;
 510
 511         while (size) {
 512                 ch = *cp++;
 513                 size--;
 514                 if (ch != '$')
 515                         continue;
 516                 if (size < 3)
 517                         break;
 518                 if (memcmp("Id", cp, 2))
 519                         continue;
 520                 ch = cp[2];
 521                 cp += 3;
 522                 size -= 3;
 523                 if (ch == '$')
 524                         cnt++; /* $Id$ */
 525                 if (ch != ':')
 526                         continue;
 527
 528                 /*
 529                  * "$Id: ... "; scan up to the closing dollar sign and discard.
 530                  */
 531                 while (size) {
 532                         ch = *cp++;
 533                         size--;
 534                         if (ch == '$') {
 535                                 cnt++;
 536                                 break;
 537                         }
 538                         if (ch == '\n')
 539                                 break;
 540                 }
 541         }
 542         return cnt;
 543 }
 544
 545 static int ident_to_git(const char *path, const char *src, size_t len,
 546                         struct strbuf *buf, int ident)
 547 {
 548         char *dst, *dollar;
 549
 550         if (!ident || (src && !count_ident(src, len)))
 551                 return 0;
 552
 553         if (!buf)
 554                 return 1;
 555
 556         /* only grow if not in place */
 557         if (strbuf_avail(buf) + buf->len < len)
 558                 strbuf_grow(buf, len - buf->len);
 559         dst = buf->buf;
 560         for (;;) {
 561                 dollar = memchr(src, '$', len);
 562                 if (!dollar)
 563                         break;
 564                 memmove(dst, src, dollar + 1 - src);
 565                 dst += dollar + 1 - src;
 566                 len -= dollar + 1 - src;
 567                 src  = dollar + 1;
 568
 569                 if (len > 3 && !memcmp(src, "Id:", 3)) {
 570                         dollar = memchr(src + 3, '$', len - 3);
 571                         if (!dollar)
 572                                 break;
 573                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 574                                 /* Line break before the next dollar. */
 575                                 continue;
 576                         }
 577
 578                         memcpy(dst, "Id$", 3);
 579                         dst += 3;
 580                         len -= dollar + 1 - src;
 581                         src  = dollar + 1;
 582                 }
 583         }
 584         memmove(dst, src, len);
 585         strbuf_setlen(buf, dst + len - buf->buf);
 586         return 1;
 587 }
 588
 589 static int ident_to_worktree(const char *path, const char *src, size_t len,
 590                              struct strbuf *buf, int ident)
 591 {
 592         unsigned char sha1[20];
 593         char *to_free = NULL, *dollar, *spc;
 594         int cnt;
 595
 596         if (!ident)
 597                 return 0;
 598
 599         cnt = count_ident(src, len);
 600         if (!cnt)
 601                 return 0;
 602
 603         /* are we "faking" in place editing ? */
 604         if (src == buf->buf)
 605                 to_free = strbuf_detach(buf, NULL);
 606         hash_sha1_file(src, len, "blob", sha1);
 607
 608         strbuf_grow(buf, len + cnt * 43);
 609         for (;;) {
 610                 /* step 1: run to the next '$' */
 611                 dollar = memchr(src, '$', len);
 612                 if (!dollar)
 613                         break;
 614                 strbuf_add(buf, src, dollar + 1 - src);
 615                 len -= dollar + 1 - src;
 616                 src  = dollar + 1;
 617
 618                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 619                 if (len < 3 || memcmp("Id", src, 2))
 620                         continue;
 621
 622                 /* step 3: skip over Id$ or Id:xxxxx$ */
 623                 if (src[2] == '$') {
 624                         src += 3;
 625                         len -= 3;
 626                 } else if (src[2] == ':') {
 627                         /*
 628                          * It's possible that an expanded Id has crept its way into the
 629                          * repository, we cope with that by stripping the expansion out.
 630                          * This is probably not a good idea, since it will cause changes
 631                          * on checkout, which won't go away by stash, but let's keep it
 632                          * for git-style ids.
 633                          */
 634                         dollar = memchr(src + 3, '$', len - 3);
 635                         if (!dollar) {
 636                                 /* incomplete keyword, no more '$', so just quit the loop */
 637                                 break;
 638                         }
 639
 640                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 641                                 /* Line break before the next dollar. */
 642                                 continue;
 643                         }
 644
 645                         spc = memchr(src + 4, ' ', dollar - src - 4);
 646                         if (spc && spc < dollar-1) {
 647                                 /* There are spaces in unexpected places.
 648                                  * This is probably an id from some other
 649                                  * versioning system. Keep it for now.
 650                                  */
 651                                 continue;
 652                         }
 653
 654                         len -= dollar + 1 - src;
 655                         src  = dollar + 1;
 656                 } else {
 657                         /* it wasn't a "Id$" or "Id:xxxx$" */
 658                         continue;
 659                 }
 660
 661                 /* step 4: substitute */
 662                 strbuf_addstr(buf, "Id: ");
 663                 strbuf_add(buf, sha1_to_hex(sha1), 40);
 664                 strbuf_addstr(buf, " $");
 665         }
 666         strbuf_add(buf, src, len);
 667
 668         free(to_free);
 669         return 1;
 670 }
 671
 672 static enum crlf_action git_path_check_crlf(const char *path, struct git_attr_check *check)
 673 {
 674         const char *value = check->value;
 675
 676         if (ATTR_TRUE(value))
 677                 return CRLF_TEXT;
 678         else if (ATTR_FALSE(value))
 679                 return CRLF_BINARY;
 680         else if (ATTR_UNSET(value))
 681                 ;
 682         else if (!strcmp(value, "input"))
 683                 return CRLF_INPUT;
 684         else if (!strcmp(value, "auto"))
 685                 return CRLF_AUTO;
 686         return CRLF_GUESS;
 687 }
 688
 689 static enum eol git_path_check_eol(const char *path, struct git_attr_check *check)
 690 {
 691         const char *value = check->value;
 692
 693         if (ATTR_UNSET(value))
 694                 ;
 695         else if (!strcmp(value, "lf"))
 696                 return EOL_LF;
 697         else if (!strcmp(value, "crlf"))
 698                 return EOL_CRLF;
 699         return EOL_UNSET;
 700 }
 701
 702 static struct convert_driver *git_path_check_convert(const char *path,
 703                                              struct git_attr_check *check)
 704 {
 705         const char *value = check->value;
 706         struct convert_driver *drv;
 707
 708         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 709                 return NULL;
 710         for (drv = user_convert; drv; drv = drv->next)
 711                 if (!strcmp(value, drv->name))
 712                         return drv;
 713         return NULL;
 714 }
 715
 716 static int git_path_check_ident(const char *path, struct git_attr_check *check)
 717 {
 718         const char *value = check->value;
 719
 720         return !!ATTR_TRUE(value);
 721 }
 722
 723 static enum crlf_action input_crlf_action(enum crlf_action text_attr, enum eol eol_attr)
 724 {
 725         if (text_attr == CRLF_BINARY)
 726                 return CRLF_BINARY;
 727         if (eol_attr == EOL_LF)
 728                 return CRLF_INPUT;
 729         if (eol_attr == EOL_CRLF)
 730                 return CRLF_CRLF;
 731         return text_attr;
 732 }
 733
 734 struct conv_attrs {
 735         struct convert_driver *drv;
 736         enum crlf_action crlf_action;
 737         enum eol eol_attr;
 738         int ident;
 739 };
 740
 741 static const char *conv_attr_name[] = {
 742         "crlf", "ident", "filter", "eol", "text",
 743 };
 744 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 745
 746 static void convert_attrs(struct conv_attrs *ca, const char *path)
 747 {
 748         int i;
 749         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 750
 751         if (!ccheck[0].attr) {
 752                 for (i = 0; i < NUM_CONV_ATTRS; i++)
 753                         ccheck[i].attr = git_attr(conv_attr_name[i]);
 754                 user_convert_tail = &user_convert;
 755                 git_config(read_convert_config, NULL);
 756         }
 757
 758         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 759                 ca->crlf_action = git_path_check_crlf(path, ccheck + 4);
 760                 if (ca->crlf_action == CRLF_GUESS)
 761                         ca->crlf_action = git_path_check_crlf(path, ccheck + 0);
 762                 ca->ident = git_path_check_ident(path, ccheck + 1);
 763                 ca->drv = git_path_check_convert(path, ccheck + 2);
 764                 ca->eol_attr = git_path_check_eol(path, ccheck + 3);
 765         } else {
 766                 ca->drv = NULL;
 767                 ca->crlf_action = CRLF_GUESS;
 768                 ca->eol_attr = EOL_UNSET;
 769                 ca->ident = 0;
 770         }
 771 }
 772
 773 int convert_to_git(const char *path, const char *src, size_t len,
 774                    struct strbuf *dst, enum safe_crlf checksafe)
 775 {
 776         int ret = 0;
 777         const char *filter = NULL;
 778         int required = 0;
 779         struct conv_attrs ca;
 780
 781         convert_attrs(&ca, path);
 782         if (ca.drv) {
 783                 filter = ca.drv->clean;
 784                 required = ca.drv->required;
 785         }
 786
 787         ret |= apply_filter(path, src, len, dst, filter);
 788         if (!ret && required)
 789                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 790
 791         if (ret && dst) {
 792                 src = dst->buf;
 793                 len = dst->len;
 794         }
 795         ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 796         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 797         if (ret && dst) {
 798                 src = dst->buf;
 799                 len = dst->len;
 800         }
 801         return ret | ident_to_git(path, src, len, dst, ca.ident);
 802 }
 803
 804 static int convert_to_working_tree_internal(const char *path, const char *src,
 805                                             size_t len, struct strbuf *dst,
 806                                             int normalizing)
 807 {
 808         int ret = 0, ret_filter = 0;
 809         const char *filter = NULL;
 810         int required = 0;
 811         struct conv_attrs ca;
 812
 813         convert_attrs(&ca, path);
 814         if (ca.drv) {
 815                 filter = ca.drv->smudge;
 816                 required = ca.drv->required;
 817         }
 818
 819         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 820         if (ret) {
 821                 src = dst->buf;
 822                 len = dst->len;
 823         }
 824         /*
 825          * CRLF conversion can be skipped if normalizing, unless there
 826          * is a smudge filter.  The filter might expect CRLFs.
 827          */
 828         if (filter || !normalizing) {
 829                 ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 830                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 831                 if (ret) {
 832                         src = dst->buf;
 833                         len = dst->len;
 834                 }
 835         }
 836
 837         ret_filter = apply_filter(path, src, len, dst, filter);
 838         if (!ret_filter && required)
 839                 die("%s: smudge filter %s failed", path, ca.drv->name);
 840
 841         return ret | ret_filter;
 842 }
 843
 844 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 845 {
 846         return convert_to_working_tree_internal(path, src, len, dst, 0);
 847 }
 848
 849 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 850 {
 851         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 852         if (ret) {
 853                 src = dst->buf;
 854                 len = dst->len;
 855         }
 856         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
 857 }
 858
 859 /*****************************************************************
 860  *
 861  * Streaming converison support
 862  *
 863  *****************************************************************/
 864
 865 typedef int (*filter_fn)(struct stream_filter *,
 866                          const char *input, size_t *isize_p,
 867                          char *output, size_t *osize_p);
 868 typedef void (*free_fn)(struct stream_filter *);
 869
 870 struct stream_filter_vtbl {
 871         filter_fn filter;
 872         free_fn free;
 873 };
 874
 875 struct stream_filter {
 876         struct stream_filter_vtbl *vtbl;
 877 };
 878
 879 static int null_filter_fn(struct stream_filter *filter,
 880                           const char *input, size_t *isize_p,
 881                           char *output, size_t *osize_p)
 882 {
 883         size_t count;
 884
 885         if (!input)
 886                 return 0; /* we do not keep any states */
 887         count = *isize_p;
 888         if (*osize_p < count)
 889                 count = *osize_p;
 890         if (count) {
 891                 memmove(output, input, count);
 892                 *isize_p -= count;
 893                 *osize_p -= count;
 894         }
 895         return 0;
 896 }
 897
 898 static void null_free_fn(struct stream_filter *filter)
 899 {
 900         ; /* nothing -- null instances are shared */
 901 }
 902
 903 static struct stream_filter_vtbl null_vtbl = {
 904         null_filter_fn,
 905         null_free_fn,
 906 };
 907
 908 static struct stream_filter null_filter_singleton = {
 909         &null_vtbl,
 910 };
 911
 912 int is_null_stream_filter(struct stream_filter *filter)
 913 {
 914         return filter == &null_filter_singleton;
 915 }
 916
 917
 918 /*
 919  * LF-to-CRLF filter
 920  */
 921
 922 struct lf_to_crlf_filter {
 923         struct stream_filter filter;
 924         unsigned has_held:1;
 925         char held;
 926 };
 927
 928 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
 929                                 const char *input, size_t *isize_p,
 930                                 char *output, size_t *osize_p)
 931 {
 932         size_t count, o = 0;
 933         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
 934
 935         /*
 936          * We may be holding onto the CR to see if it is followed by a
 937          * LF, in which case we would need to go to the main loop.
 938          * Otherwise, just emit it to the output stream.
 939          */
 940         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
 941                 output[o++] = lf_to_crlf->held;
 942                 lf_to_crlf->has_held = 0;
 943         }
 944
 945         /* We are told to drain */
 946         if (!input) {
 947                 *osize_p -= o;
 948                 return 0;
 949         }
 950
 951         count = *isize_p;
 952         if (count || lf_to_crlf->has_held) {
 953                 size_t i;
 954                 int was_cr = 0;
 955
 956                 if (lf_to_crlf->has_held) {
 957                         was_cr = 1;
 958                         lf_to_crlf->has_held = 0;
 959                 }
 960
 961                 for (i = 0; o < *osize_p && i < count; i++) {
 962                         char ch = input[i];
 963
 964                         if (ch == '\n') {
 965                                 output[o++] = '\r';
 966                         } else if (was_cr) {
 967                                 /*
 968                                  * Previous round saw CR and it is not followed
 969                                  * by a LF; emit the CR before processing the
 970                                  * current character.
 971                                  */
 972                                 output[o++] = '\r';
 973                         }
 974
 975                         /*
 976                          * We may have consumed the last output slot,
 977                          * in which case we need to break out of this
 978                          * loop; hold the current character before
 979                          * returning.
 980                          */
 981                         if (*osize_p <= o) {
 982                                 lf_to_crlf->has_held = 1;
 983                                 lf_to_crlf->held = ch;
 984                                 continue; /* break but increment i */
 985                         }
 986
 987                         if (ch == '\r') {
 988                                 was_cr = 1;
 989                                 continue;
 990                         }
 991
 992                         was_cr = 0;
 993                         output[o++] = ch;
 994                 }
 995
 996                 *osize_p -= o;
 997                 *isize_p -= i;
 998
 999                 if (!lf_to_crlf->has_held && was_cr) {
1000                         lf_to_crlf->has_held = 1;
1001                         lf_to_crlf->held = '\r';
1002                 }
1003         }
1004         return 0;
1005 }
1006
1007 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1008 {
1009         free(filter);
1010 }
1011
1012 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1013         lf_to_crlf_filter_fn,
1014         lf_to_crlf_free_fn,
1015 };
1016
1017 static struct stream_filter *lf_to_crlf_filter(void)
1018 {
1019         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1020
1021         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1022         return (struct stream_filter *)lf_to_crlf;
1023 }
1024
1025 /*
1026  * Cascade filter
1027  */
1028 #define FILTER_BUFFER 1024
1029 struct cascade_filter {
1030         struct stream_filter filter;
1031         struct stream_filter *one;
1032         struct stream_filter *two;
1033         char buf[FILTER_BUFFER];
1034         int end, ptr;
1035 };
1036
1037 static int cascade_filter_fn(struct stream_filter *filter,
1038                              const char *input, size_t *isize_p,
1039                              char *output, size_t *osize_p)
1040 {
1041         struct cascade_filter *cas = (struct cascade_filter *) filter;
1042         size_t filled = 0;
1043         size_t sz = *osize_p;
1044         size_t to_feed, remaining;
1045
1046         /*
1047          * input -- (one) --> buf -- (two) --> output
1048          */
1049         while (filled < sz) {
1050                 remaining = sz - filled;
1051
1052                 /* do we already have something to feed two with? */
1053                 if (cas->ptr < cas->end) {
1054                         to_feed = cas->end - cas->ptr;
1055                         if (stream_filter(cas->two,
1056                                           cas->buf + cas->ptr, &to_feed,
1057                                           output + filled, &remaining))
1058                                 return -1;
1059                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1060                         filled = sz - remaining;
1061                         continue;
1062                 }
1063
1064                 /* feed one from upstream and have it emit into our buffer */
1065                 to_feed = input ? *isize_p : 0;
1066                 if (input && !to_feed)
1067                         break;
1068                 remaining = sizeof(cas->buf);
1069                 if (stream_filter(cas->one,
1070                                   input, &to_feed,
1071                                   cas->buf, &remaining))
1072                         return -1;
1073                 cas->end = sizeof(cas->buf) - remaining;
1074                 cas->ptr = 0;
1075                 if (input) {
1076                         size_t fed = *isize_p - to_feed;
1077                         *isize_p -= fed;
1078                         input += fed;
1079                 }
1080
1081                 /* do we know that we drained one completely? */
1082                 if (input || cas->end)
1083                         continue;
1084
1085                 /* tell two to drain; we have nothing more to give it */
1086                 to_feed = 0;
1087                 remaining = sz - filled;
1088                 if (stream_filter(cas->two,
1089                                   NULL, &to_feed,
1090                                   output + filled, &remaining))
1091                         return -1;
1092                 if (remaining == (sz - filled))
1093                         break; /* completely drained two */
1094                 filled = sz - remaining;
1095         }
1096         *osize_p -= filled;
1097         return 0;
1098 }
1099
1100 static void cascade_free_fn(struct stream_filter *filter)
1101 {
1102         struct cascade_filter *cas = (struct cascade_filter *)filter;
1103         free_stream_filter(cas->one);
1104         free_stream_filter(cas->two);
1105         free(filter);
1106 }
1107
1108 static struct stream_filter_vtbl cascade_vtbl = {
1109         cascade_filter_fn,
1110         cascade_free_fn,
1111 };
1112
1113 static struct stream_filter *cascade_filter(struct stream_filter *one,
1114                                             struct stream_filter *two)
1115 {
1116         struct cascade_filter *cascade;
1117
1118         if (!one || is_null_stream_filter(one))
1119                 return two;
1120         if (!two || is_null_stream_filter(two))
1121                 return one;
1122
1123         cascade = xmalloc(sizeof(*cascade));
1124         cascade->one = one;
1125         cascade->two = two;
1126         cascade->end = cascade->ptr = 0;
1127         cascade->filter.vtbl = &cascade_vtbl;
1128         return (struct stream_filter *)cascade;
1129 }
1130
1131 /*
1132  * ident filter
1133  */
1134 #define IDENT_DRAINING (-1)
1135 #define IDENT_SKIPPING (-2)
1136 struct ident_filter {
1137         struct stream_filter filter;
1138         struct strbuf left;
1139         int state;
1140         char ident[45]; /* ": x40 $" */
1141 };
1142
1143 static int is_foreign_ident(const char *str)
1144 {
1145         int i;
1146
1147         if (prefixcmp(str, "$Id: "))
1148                 return 0;
1149         for (i = 5; str[i]; i++) {
1150                 if (isspace(str[i]) && str[i+1] != '$')
1151                         return 1;
1152         }
1153         return 0;
1154 }
1155
1156 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1157 {
1158         size_t to_drain = ident->left.len;
1159
1160         if (*osize_p < to_drain)
1161                 to_drain = *osize_p;
1162         if (to_drain) {
1163                 memcpy(*output_p, ident->left.buf, to_drain);
1164                 strbuf_remove(&ident->left, 0, to_drain);
1165                 *output_p += to_drain;
1166                 *osize_p -= to_drain;
1167         }
1168         if (!ident->left.len)
1169                 ident->state = 0;
1170 }
1171
1172 static int ident_filter_fn(struct stream_filter *filter,
1173                            const char *input, size_t *isize_p,
1174                            char *output, size_t *osize_p)
1175 {
1176         struct ident_filter *ident = (struct ident_filter *)filter;
1177         static const char head[] = "$Id";
1178
1179         if (!input) {
1180                 /* drain upon eof */
1181                 switch (ident->state) {
1182                 default:
1183                         strbuf_add(&ident->left, head, ident->state);
1184                 case IDENT_SKIPPING:
1185                         /* fallthru */
1186                 case IDENT_DRAINING:
1187                         ident_drain(ident, &output, osize_p);
1188                 }
1189                 return 0;
1190         }
1191
1192         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1193                 int ch;
1194
1195                 if (ident->state == IDENT_DRAINING) {
1196                         ident_drain(ident, &output, osize_p);
1197                         if (!*osize_p)
1198                                 break;
1199                         continue;
1200                 }
1201
1202                 ch = *(input++);
1203                 (*isize_p)--;
1204
1205                 if (ident->state == IDENT_SKIPPING) {
1206                         /*
1207                          * Skipping until '$' or LF, but keeping them
1208                          * in case it is a foreign ident.
1209                          */
1210                         strbuf_addch(&ident->left, ch);
1211                         if (ch != '\n' && ch != '$')
1212                                 continue;
1213                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1214                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1215                                 strbuf_addstr(&ident->left, ident->ident);
1216                         }
1217                         ident->state = IDENT_DRAINING;
1218                         continue;
1219                 }
1220
1221                 if (ident->state < sizeof(head) &&
1222                     head[ident->state] == ch) {
1223                         ident->state++;
1224                         continue;
1225                 }
1226
1227                 if (ident->state)
1228                         strbuf_add(&ident->left, head, ident->state);
1229                 if (ident->state == sizeof(head) - 1) {
1230                         if (ch != ':' && ch != '$') {
1231                                 strbuf_addch(&ident->left, ch);
1232                                 ident->state = 0;
1233                                 continue;
1234                         }
1235
1236                         if (ch == ':') {
1237                                 strbuf_addch(&ident->left, ch);
1238                                 ident->state = IDENT_SKIPPING;
1239                         } else {
1240                                 strbuf_addstr(&ident->left, ident->ident);
1241                                 ident->state = IDENT_DRAINING;
1242                         }
1243                         continue;
1244                 }
1245
1246                 strbuf_addch(&ident->left, ch);
1247                 ident->state = IDENT_DRAINING;
1248         }
1249         return 0;
1250 }
1251
1252 static void ident_free_fn(struct stream_filter *filter)
1253 {
1254         struct ident_filter *ident = (struct ident_filter *)filter;
1255         strbuf_release(&ident->left);
1256         free(filter);
1257 }
1258
1259 static struct stream_filter_vtbl ident_vtbl = {
1260         ident_filter_fn,
1261         ident_free_fn,
1262 };
1263
1264 static struct stream_filter *ident_filter(const unsigned char *sha1)
1265 {
1266         struct ident_filter *ident = xmalloc(sizeof(*ident));
1267
1268         sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
1269         strbuf_init(&ident->left, 0);
1270         ident->filter.vtbl = &ident_vtbl;
1271         ident->state = 0;
1272         return (struct stream_filter *)ident;
1273 }
1274
1275 /*
1276  * Return an appropriately constructed filter for the path, or NULL if
1277  * the contents cannot be filtered without reading the whole thing
1278  * in-core.
1279  *
1280  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1281  * large binary blob you would want us not to slurp into the memory!
1282  */
1283 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1284 {
1285         struct conv_attrs ca;
1286         enum crlf_action crlf_action;
1287         struct stream_filter *filter = NULL;
1288
1289         convert_attrs(&ca, path);
1290
1291         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1292                 return filter;
1293
1294         if (ca.ident)
1295                 filter = ident_filter(sha1);
1296
1297         crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
1298
1299         if ((crlf_action == CRLF_BINARY) || (crlf_action == CRLF_INPUT) ||
1300             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
1301                 filter = cascade_filter(filter, &null_filter_singleton);
1302
1303         else if (output_eol(crlf_action) == EOL_CRLF &&
1304                  !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
1305                 filter = cascade_filter(filter, lf_to_crlf_filter());
1306
1307         return filter;
1308 }
1309
1310 void free_stream_filter(struct stream_filter *filter)
1311 {
1312         filter->vtbl->free(filter);
1313 }
1314
1315 int stream_filter(struct stream_filter *filter,
1316                   const char *input, size_t *isize_p,
1317                   char *output, size_t *osize_p)
1318 {
1319         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1320 }