git.oblomov.eu Git - git/blob - 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 *ep, *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 (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
 469                 return 0;
 470         name = var + 7;
 471         namelen = ep - name;
 472         for (drv = user_convert; drv; drv = drv->next)
 473                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 474                         break;
 475         if (!drv) {
 476                 drv = xcalloc(1, sizeof(struct convert_driver));
 477                 drv->name = xmemdupz(name, namelen);
 478                 *user_convert_tail = drv;
 479                 user_convert_tail = &(drv->next);
 480         }
 481
 482         ep++;
 483
 484         /*
 485          * filter.<name>.smudge and filter.<name>.clean specifies
 486          * the command line:
 487          *
 488          *      command-line
 489          *
 490          * The command-line will not be interpolated in any way.
 491          */
 492
 493         if (!strcmp("smudge", ep))
 494                 return git_config_string(&drv->smudge, var, value);
 495
 496         if (!strcmp("clean", ep))
 497                 return git_config_string(&drv->clean, var, value);
 498
 499         if (!strcmp("required", ep)) {
 500                 drv->required = git_config_bool(var, value);
 501                 return 0;
 502         }
 503
 504         return 0;
 505 }
 506
 507 static int count_ident(const char *cp, unsigned long size)
 508 {
 509         /*
 510          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 511          */
 512         int cnt = 0;
 513         char ch;
 514
 515         while (size) {
 516                 ch = *cp++;
 517                 size--;
 518                 if (ch != '$')
 519                         continue;
 520                 if (size < 3)
 521                         break;
 522                 if (memcmp("Id", cp, 2))
 523                         continue;
 524                 ch = cp[2];
 525                 cp += 3;
 526                 size -= 3;
 527                 if (ch == '$')
 528                         cnt++; /* $Id$ */
 529                 if (ch != ':')
 530                         continue;
 531
 532                 /*
 533                  * "$Id: ... "; scan up to the closing dollar sign and discard.
 534                  */
 535                 while (size) {
 536                         ch = *cp++;
 537                         size--;
 538                         if (ch == '$') {
 539                                 cnt++;
 540                                 break;
 541                         }
 542                         if (ch == '\n')
 543                                 break;
 544                 }
 545         }
 546         return cnt;
 547 }
 548
 549 static int ident_to_git(const char *path, const char *src, size_t len,
 550                         struct strbuf *buf, int ident)
 551 {
 552         char *dst, *dollar;
 553
 554         if (!ident || (src && !count_ident(src, len)))
 555                 return 0;
 556
 557         if (!buf)
 558                 return 1;
 559
 560         /* only grow if not in place */
 561         if (strbuf_avail(buf) + buf->len < len)
 562                 strbuf_grow(buf, len - buf->len);
 563         dst = buf->buf;
 564         for (;;) {
 565                 dollar = memchr(src, '$', len);
 566                 if (!dollar)
 567                         break;
 568                 memmove(dst, src, dollar + 1 - src);
 569                 dst += dollar + 1 - src;
 570                 len -= dollar + 1 - src;
 571                 src  = dollar + 1;
 572
 573                 if (len > 3 && !memcmp(src, "Id:", 3)) {
 574                         dollar = memchr(src + 3, '$', len - 3);
 575                         if (!dollar)
 576                                 break;
 577                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 578                                 /* Line break before the next dollar. */
 579                                 continue;
 580                         }
 581
 582                         memcpy(dst, "Id$", 3);
 583                         dst += 3;
 584                         len -= dollar + 1 - src;
 585                         src  = dollar + 1;
 586                 }
 587         }
 588         memmove(dst, src, len);
 589         strbuf_setlen(buf, dst + len - buf->buf);
 590         return 1;
 591 }
 592
 593 static int ident_to_worktree(const char *path, const char *src, size_t len,
 594                              struct strbuf *buf, int ident)
 595 {
 596         unsigned char sha1[20];
 597         char *to_free = NULL, *dollar, *spc;
 598         int cnt;
 599
 600         if (!ident)
 601                 return 0;
 602
 603         cnt = count_ident(src, len);
 604         if (!cnt)
 605                 return 0;
 606
 607         /* are we "faking" in place editing ? */
 608         if (src == buf->buf)
 609                 to_free = strbuf_detach(buf, NULL);
 610         hash_sha1_file(src, len, "blob", sha1);
 611
 612         strbuf_grow(buf, len + cnt * 43);
 613         for (;;) {
 614                 /* step 1: run to the next '$' */
 615                 dollar = memchr(src, '$', len);
 616                 if (!dollar)
 617                         break;
 618                 strbuf_add(buf, src, dollar + 1 - src);
 619                 len -= dollar + 1 - src;
 620                 src  = dollar + 1;
 621
 622                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 623                 if (len < 3 || memcmp("Id", src, 2))
 624                         continue;
 625
 626                 /* step 3: skip over Id$ or Id:xxxxx$ */
 627                 if (src[2] == '$') {
 628                         src += 3;
 629                         len -= 3;
 630                 } else if (src[2] == ':') {
 631                         /*
 632                          * It's possible that an expanded Id has crept its way into the
 633                          * repository, we cope with that by stripping the expansion out.
 634                          * This is probably not a good idea, since it will cause changes
 635                          * on checkout, which won't go away by stash, but let's keep it
 636                          * for git-style ids.
 637                          */
 638                         dollar = memchr(src + 3, '$', len - 3);
 639                         if (!dollar) {
 640                                 /* incomplete keyword, no more '$', so just quit the loop */
 641                                 break;
 642                         }
 643
 644                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 645                                 /* Line break before the next dollar. */
 646                                 continue;
 647                         }
 648
 649                         spc = memchr(src + 4, ' ', dollar - src - 4);
 650                         if (spc && spc < dollar-1) {
 651                                 /* There are spaces in unexpected places.
 652                                  * This is probably an id from some other
 653                                  * versioning system. Keep it for now.
 654                                  */
 655                                 continue;
 656                         }
 657
 658                         len -= dollar + 1 - src;
 659                         src  = dollar + 1;
 660                 } else {
 661                         /* it wasn't a "Id$" or "Id:xxxx$" */
 662                         continue;
 663                 }
 664
 665                 /* step 4: substitute */
 666                 strbuf_addstr(buf, "Id: ");
 667                 strbuf_add(buf, sha1_to_hex(sha1), 40);
 668                 strbuf_addstr(buf, " $");
 669         }
 670         strbuf_add(buf, src, len);
 671
 672         free(to_free);
 673         return 1;
 674 }
 675
 676 static enum crlf_action git_path_check_crlf(const char *path, struct git_attr_check *check)
 677 {
 678         const char *value = check->value;
 679
 680         if (ATTR_TRUE(value))
 681                 return CRLF_TEXT;
 682         else if (ATTR_FALSE(value))
 683                 return CRLF_BINARY;
 684         else if (ATTR_UNSET(value))
 685                 ;
 686         else if (!strcmp(value, "input"))
 687                 return CRLF_INPUT;
 688         else if (!strcmp(value, "auto"))
 689                 return CRLF_AUTO;
 690         return CRLF_GUESS;
 691 }
 692
 693 static enum eol git_path_check_eol(const char *path, struct git_attr_check *check)
 694 {
 695         const char *value = check->value;
 696
 697         if (ATTR_UNSET(value))
 698                 ;
 699         else if (!strcmp(value, "lf"))
 700                 return EOL_LF;
 701         else if (!strcmp(value, "crlf"))
 702                 return EOL_CRLF;
 703         return EOL_UNSET;
 704 }
 705
 706 static struct convert_driver *git_path_check_convert(const char *path,
 707                                              struct git_attr_check *check)
 708 {
 709         const char *value = check->value;
 710         struct convert_driver *drv;
 711
 712         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 713                 return NULL;
 714         for (drv = user_convert; drv; drv = drv->next)
 715                 if (!strcmp(value, drv->name))
 716                         return drv;
 717         return NULL;
 718 }
 719
 720 static int git_path_check_ident(const char *path, struct git_attr_check *check)
 721 {
 722         const char *value = check->value;
 723
 724         return !!ATTR_TRUE(value);
 725 }
 726
 727 static enum crlf_action input_crlf_action(enum crlf_action text_attr, enum eol eol_attr)
 728 {
 729         if (text_attr == CRLF_BINARY)
 730                 return CRLF_BINARY;
 731         if (eol_attr == EOL_LF)
 732                 return CRLF_INPUT;
 733         if (eol_attr == EOL_CRLF)
 734                 return CRLF_CRLF;
 735         return text_attr;
 736 }
 737
 738 struct conv_attrs {
 739         struct convert_driver *drv;
 740         enum crlf_action crlf_action;
 741         enum eol eol_attr;
 742         int ident;
 743 };
 744
 745 static const char *conv_attr_name[] = {
 746         "crlf", "ident", "filter", "eol", "text",
 747 };
 748 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 749
 750 static void convert_attrs(struct conv_attrs *ca, const char *path)
 751 {
 752         int i;
 753         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 754
 755         if (!ccheck[0].attr) {
 756                 for (i = 0; i < NUM_CONV_ATTRS; i++)
 757                         ccheck[i].attr = git_attr(conv_attr_name[i]);
 758                 user_convert_tail = &user_convert;
 759                 git_config(read_convert_config, NULL);
 760         }
 761
 762         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 763                 ca->crlf_action = git_path_check_crlf(path, ccheck + 4);
 764                 if (ca->crlf_action == CRLF_GUESS)
 765                         ca->crlf_action = git_path_check_crlf(path, ccheck + 0);
 766                 ca->ident = git_path_check_ident(path, ccheck + 1);
 767                 ca->drv = git_path_check_convert(path, ccheck + 2);
 768                 ca->eol_attr = git_path_check_eol(path, ccheck + 3);
 769         } else {
 770                 ca->drv = NULL;
 771                 ca->crlf_action = CRLF_GUESS;
 772                 ca->eol_attr = EOL_UNSET;
 773                 ca->ident = 0;
 774         }
 775 }
 776
 777 int convert_to_git(const char *path, const char *src, size_t len,
 778                    struct strbuf *dst, enum safe_crlf checksafe)
 779 {
 780         int ret = 0;
 781         const char *filter = NULL;
 782         int required = 0;
 783         struct conv_attrs ca;
 784
 785         convert_attrs(&ca, path);
 786         if (ca.drv) {
 787                 filter = ca.drv->clean;
 788                 required = ca.drv->required;
 789         }
 790
 791         ret |= apply_filter(path, src, len, dst, filter);
 792         if (!ret && required)
 793                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 794
 795         if (ret && dst) {
 796                 src = dst->buf;
 797                 len = dst->len;
 798         }
 799         ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 800         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 801         if (ret && dst) {
 802                 src = dst->buf;
 803                 len = dst->len;
 804         }
 805         return ret | ident_to_git(path, src, len, dst, ca.ident);
 806 }
 807
 808 static int convert_to_working_tree_internal(const char *path, const char *src,
 809                                             size_t len, struct strbuf *dst,
 810                                             int normalizing)
 811 {
 812         int ret = 0, ret_filter = 0;
 813         const char *filter = NULL;
 814         int required = 0;
 815         struct conv_attrs ca;
 816
 817         convert_attrs(&ca, path);
 818         if (ca.drv) {
 819                 filter = ca.drv->smudge;
 820                 required = ca.drv->required;
 821         }
 822
 823         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 824         if (ret) {
 825                 src = dst->buf;
 826                 len = dst->len;
 827         }
 828         /*
 829          * CRLF conversion can be skipped if normalizing, unless there
 830          * is a smudge filter.  The filter might expect CRLFs.
 831          */
 832         if (filter || !normalizing) {
 833                 ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 834                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 835                 if (ret) {
 836                         src = dst->buf;
 837                         len = dst->len;
 838                 }
 839         }
 840
 841         ret_filter = apply_filter(path, src, len, dst, filter);
 842         if (!ret_filter && required)
 843                 die("%s: smudge filter %s failed", path, ca.drv->name);
 844
 845         return ret | ret_filter;
 846 }
 847
 848 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 849 {
 850         return convert_to_working_tree_internal(path, src, len, dst, 0);
 851 }
 852
 853 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 854 {
 855         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 856         if (ret) {
 857                 src = dst->buf;
 858                 len = dst->len;
 859         }
 860         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
 861 }
 862
 863 /*****************************************************************
 864  *
 865  * Streaming converison support
 866  *
 867  *****************************************************************/
 868
 869 typedef int (*filter_fn)(struct stream_filter *,
 870                          const char *input, size_t *isize_p,
 871                          char *output, size_t *osize_p);
 872 typedef void (*free_fn)(struct stream_filter *);
 873
 874 struct stream_filter_vtbl {
 875         filter_fn filter;
 876         free_fn free;
 877 };
 878
 879 struct stream_filter {
 880         struct stream_filter_vtbl *vtbl;
 881 };
 882
 883 static int null_filter_fn(struct stream_filter *filter,
 884                           const char *input, size_t *isize_p,
 885                           char *output, size_t *osize_p)
 886 {
 887         size_t count;
 888
 889         if (!input)
 890                 return 0; /* we do not keep any states */
 891         count = *isize_p;
 892         if (*osize_p < count)
 893                 count = *osize_p;
 894         if (count) {
 895                 memmove(output, input, count);
 896                 *isize_p -= count;
 897                 *osize_p -= count;
 898         }
 899         return 0;
 900 }
 901
 902 static void null_free_fn(struct stream_filter *filter)
 903 {
 904         ; /* nothing -- null instances are shared */
 905 }
 906
 907 static struct stream_filter_vtbl null_vtbl = {
 908         null_filter_fn,
 909         null_free_fn,
 910 };
 911
 912 static struct stream_filter null_filter_singleton = {
 913         &null_vtbl,
 914 };
 915
 916 int is_null_stream_filter(struct stream_filter *filter)
 917 {
 918         return filter == &null_filter_singleton;
 919 }
 920
 921
 922 /*
 923  * LF-to-CRLF filter
 924  */
 925
 926 struct lf_to_crlf_filter {
 927         struct stream_filter filter;
 928         unsigned has_held:1;
 929         char held;
 930 };
 931
 932 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
 933                                 const char *input, size_t *isize_p,
 934                                 char *output, size_t *osize_p)
 935 {
 936         size_t count, o = 0;
 937         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
 938
 939         /*
 940          * We may be holding onto the CR to see if it is followed by a
 941          * LF, in which case we would need to go to the main loop.
 942          * Otherwise, just emit it to the output stream.
 943          */
 944         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
 945                 output[o++] = lf_to_crlf->held;
 946                 lf_to_crlf->has_held = 0;
 947         }
 948
 949         /* We are told to drain */
 950         if (!input) {
 951                 *osize_p -= o;
 952                 return 0;
 953         }
 954
 955         count = *isize_p;
 956         if (count || lf_to_crlf->has_held) {
 957                 size_t i;
 958                 int was_cr = 0;
 959
 960                 if (lf_to_crlf->has_held) {
 961                         was_cr = 1;
 962                         lf_to_crlf->has_held = 0;
 963                 }
 964
 965                 for (i = 0; o < *osize_p && i < count; i++) {
 966                         char ch = input[i];
 967
 968                         if (ch == '\n') {
 969                                 output[o++] = '\r';
 970                         } else if (was_cr) {
 971                                 /*
 972                                  * Previous round saw CR and it is not followed
 973                                  * by a LF; emit the CR before processing the
 974                                  * current character.
 975                                  */
 976                                 output[o++] = '\r';
 977                         }
 978
 979                         /*
 980                          * We may have consumed the last output slot,
 981                          * in which case we need to break out of this
 982                          * loop; hold the current character before
 983                          * returning.
 984                          */
 985                         if (*osize_p <= o) {
 986                                 lf_to_crlf->has_held = 1;
 987                                 lf_to_crlf->held = ch;
 988                                 continue; /* break but increment i */
 989                         }
 990
 991                         if (ch == '\r') {
 992                                 was_cr = 1;
 993                                 continue;
 994                         }
 995
 996                         was_cr = 0;
 997                         output[o++] = ch;
 998                 }
 999
1000                 *osize_p -= o;
1001                 *isize_p -= i;
1002
1003                 if (!lf_to_crlf->has_held && was_cr) {
1004                         lf_to_crlf->has_held = 1;
1005                         lf_to_crlf->held = '\r';
1006                 }
1007         }
1008         return 0;
1009 }
1010
1011 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1012 {
1013         free(filter);
1014 }
1015
1016 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1017         lf_to_crlf_filter_fn,
1018         lf_to_crlf_free_fn,
1019 };
1020
1021 static struct stream_filter *lf_to_crlf_filter(void)
1022 {
1023         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1024
1025         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1026         return (struct stream_filter *)lf_to_crlf;
1027 }
1028
1029 /*
1030  * Cascade filter
1031  */
1032 #define FILTER_BUFFER 1024
1033 struct cascade_filter {
1034         struct stream_filter filter;
1035         struct stream_filter *one;
1036         struct stream_filter *two;
1037         char buf[FILTER_BUFFER];
1038         int end, ptr;
1039 };
1040
1041 static int cascade_filter_fn(struct stream_filter *filter,
1042                              const char *input, size_t *isize_p,
1043                              char *output, size_t *osize_p)
1044 {
1045         struct cascade_filter *cas = (struct cascade_filter *) filter;
1046         size_t filled = 0;
1047         size_t sz = *osize_p;
1048         size_t to_feed, remaining;
1049
1050         /*
1051          * input -- (one) --> buf -- (two) --> output
1052          */
1053         while (filled < sz) {
1054                 remaining = sz - filled;
1055
1056                 /* do we already have something to feed two with? */
1057                 if (cas->ptr < cas->end) {
1058                         to_feed = cas->end - cas->ptr;
1059                         if (stream_filter(cas->two,
1060                                           cas->buf + cas->ptr, &to_feed,
1061                                           output + filled, &remaining))
1062                                 return -1;
1063                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1064                         filled = sz - remaining;
1065                         continue;
1066                 }
1067
1068                 /* feed one from upstream and have it emit into our buffer */
1069                 to_feed = input ? *isize_p : 0;
1070                 if (input && !to_feed)
1071                         break;
1072                 remaining = sizeof(cas->buf);
1073                 if (stream_filter(cas->one,
1074                                   input, &to_feed,
1075                                   cas->buf, &remaining))
1076                         return -1;
1077                 cas->end = sizeof(cas->buf) - remaining;
1078                 cas->ptr = 0;
1079                 if (input) {
1080                         size_t fed = *isize_p - to_feed;
1081                         *isize_p -= fed;
1082                         input += fed;
1083                 }
1084
1085                 /* do we know that we drained one completely? */
1086                 if (input || cas->end)
1087                         continue;
1088
1089                 /* tell two to drain; we have nothing more to give it */
1090                 to_feed = 0;
1091                 remaining = sz - filled;
1092                 if (stream_filter(cas->two,
1093                                   NULL, &to_feed,
1094                                   output + filled, &remaining))
1095                         return -1;
1096                 if (remaining == (sz - filled))
1097                         break; /* completely drained two */
1098                 filled = sz - remaining;
1099         }
1100         *osize_p -= filled;
1101         return 0;
1102 }
1103
1104 static void cascade_free_fn(struct stream_filter *filter)
1105 {
1106         struct cascade_filter *cas = (struct cascade_filter *)filter;
1107         free_stream_filter(cas->one);
1108         free_stream_filter(cas->two);
1109         free(filter);
1110 }
1111
1112 static struct stream_filter_vtbl cascade_vtbl = {
1113         cascade_filter_fn,
1114         cascade_free_fn,
1115 };
1116
1117 static struct stream_filter *cascade_filter(struct stream_filter *one,
1118                                             struct stream_filter *two)
1119 {
1120         struct cascade_filter *cascade;
1121
1122         if (!one || is_null_stream_filter(one))
1123                 return two;
1124         if (!two || is_null_stream_filter(two))
1125                 return one;
1126
1127         cascade = xmalloc(sizeof(*cascade));
1128         cascade->one = one;
1129         cascade->two = two;
1130         cascade->end = cascade->ptr = 0;
1131         cascade->filter.vtbl = &cascade_vtbl;
1132         return (struct stream_filter *)cascade;
1133 }
1134
1135 /*
1136  * ident filter
1137  */
1138 #define IDENT_DRAINING (-1)
1139 #define IDENT_SKIPPING (-2)
1140 struct ident_filter {
1141         struct stream_filter filter;
1142         struct strbuf left;
1143         int state;
1144         char ident[45]; /* ": x40 $" */
1145 };
1146
1147 static int is_foreign_ident(const char *str)
1148 {
1149         int i;
1150
1151         if (prefixcmp(str, "$Id: "))
1152                 return 0;
1153         for (i = 5; str[i]; i++) {
1154                 if (isspace(str[i]) && str[i+1] != '$')
1155                         return 1;
1156         }
1157         return 0;
1158 }
1159
1160 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1161 {
1162         size_t to_drain = ident->left.len;
1163
1164         if (*osize_p < to_drain)
1165                 to_drain = *osize_p;
1166         if (to_drain) {
1167                 memcpy(*output_p, ident->left.buf, to_drain);
1168                 strbuf_remove(&ident->left, 0, to_drain);
1169                 *output_p += to_drain;
1170                 *osize_p -= to_drain;
1171         }
1172         if (!ident->left.len)
1173                 ident->state = 0;
1174 }
1175
1176 static int ident_filter_fn(struct stream_filter *filter,
1177                            const char *input, size_t *isize_p,
1178                            char *output, size_t *osize_p)
1179 {
1180         struct ident_filter *ident = (struct ident_filter *)filter;
1181         static const char head[] = "$Id";
1182
1183         if (!input) {
1184                 /* drain upon eof */
1185                 switch (ident->state) {
1186                 default:
1187                         strbuf_add(&ident->left, head, ident->state);
1188                 case IDENT_SKIPPING:
1189                         /* fallthru */
1190                 case IDENT_DRAINING:
1191                         ident_drain(ident, &output, osize_p);
1192                 }
1193                 return 0;
1194         }
1195
1196         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1197                 int ch;
1198
1199                 if (ident->state == IDENT_DRAINING) {
1200                         ident_drain(ident, &output, osize_p);
1201                         if (!*osize_p)
1202                                 break;
1203                         continue;
1204                 }
1205
1206                 ch = *(input++);
1207                 (*isize_p)--;
1208
1209                 if (ident->state == IDENT_SKIPPING) {
1210                         /*
1211                          * Skipping until '$' or LF, but keeping them
1212                          * in case it is a foreign ident.
1213                          */
1214                         strbuf_addch(&ident->left, ch);
1215                         if (ch != '\n' && ch != '$')
1216                                 continue;
1217                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1218                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1219                                 strbuf_addstr(&ident->left, ident->ident);
1220                         }
1221                         ident->state = IDENT_DRAINING;
1222                         continue;
1223                 }
1224
1225                 if (ident->state < sizeof(head) &&
1226                     head[ident->state] == ch) {
1227                         ident->state++;
1228                         continue;
1229                 }
1230
1231                 if (ident->state)
1232                         strbuf_add(&ident->left, head, ident->state);
1233                 if (ident->state == sizeof(head) - 1) {
1234                         if (ch != ':' && ch != '$') {
1235                                 strbuf_addch(&ident->left, ch);
1236                                 ident->state = 0;
1237                                 continue;
1238                         }
1239
1240                         if (ch == ':') {
1241                                 strbuf_addch(&ident->left, ch);
1242                                 ident->state = IDENT_SKIPPING;
1243                         } else {
1244                                 strbuf_addstr(&ident->left, ident->ident);
1245                                 ident->state = IDENT_DRAINING;
1246                         }
1247                         continue;
1248                 }
1249
1250                 strbuf_addch(&ident->left, ch);
1251                 ident->state = IDENT_DRAINING;
1252         }
1253         return 0;
1254 }
1255
1256 static void ident_free_fn(struct stream_filter *filter)
1257 {
1258         struct ident_filter *ident = (struct ident_filter *)filter;
1259         strbuf_release(&ident->left);
1260         free(filter);
1261 }
1262
1263 static struct stream_filter_vtbl ident_vtbl = {
1264         ident_filter_fn,
1265         ident_free_fn,
1266 };
1267
1268 static struct stream_filter *ident_filter(const unsigned char *sha1)
1269 {
1270         struct ident_filter *ident = xmalloc(sizeof(*ident));
1271
1272         sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
1273         strbuf_init(&ident->left, 0);
1274         ident->filter.vtbl = &ident_vtbl;
1275         ident->state = 0;
1276         return (struct stream_filter *)ident;
1277 }
1278
1279 /*
1280  * Return an appropriately constructed filter for the path, or NULL if
1281  * the contents cannot be filtered without reading the whole thing
1282  * in-core.
1283  *
1284  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1285  * large binary blob you would want us not to slurp into the memory!
1286  */
1287 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1288 {
1289         struct conv_attrs ca;
1290         enum crlf_action crlf_action;
1291         struct stream_filter *filter = NULL;
1292
1293         convert_attrs(&ca, path);
1294
1295         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1296                 return filter;
1297
1298         if (ca.ident)
1299                 filter = ident_filter(sha1);
1300
1301         crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
1302
1303         if ((crlf_action == CRLF_BINARY) || (crlf_action == CRLF_INPUT) ||
1304             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
1305                 filter = cascade_filter(filter, &null_filter_singleton);
1306
1307         else if (output_eol(crlf_action) == EOL_CRLF &&
1308                  !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
1309                 filter = cascade_filter(filter, lf_to_crlf_filter());
1310
1311         return filter;
1312 }
1313
1314 void free_stream_filter(struct stream_filter *filter)
1315 {
1316         filter->vtbl->free(filter);
1317 }
1318
1319 int stream_filter(struct stream_filter *filter,
1320                   const char *input, size_t *isize_p,
1321                   char *output, size_t *osize_p)
1322 {
1323         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1324 }