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         unsigned long sz;
 157         void *data;
 158         int has_cr;
 159
 160         data = read_blob_data_from_cache(path, &sz);
 161         if (!data)
 162                 return 0;
 163         has_cr = memchr(data, '\r', sz) != NULL;
 164         free(data);
 165         return has_cr;
 166 }
 167
 168 static int crlf_to_git(const char *path, const char *src, size_t len,
 169                        struct strbuf *buf,
 170                        enum crlf_action crlf_action, enum safe_crlf checksafe)
 171 {
 172         struct text_stat stats;
 173         char *dst;
 174
 175         if (crlf_action == CRLF_BINARY ||
 176             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE) ||
 177             (src && !len))
 178                 return 0;
 179
 180         /*
 181          * If we are doing a dry-run and have no source buffer, there is
 182          * nothing to analyze; we must assume we would convert.
 183          */
 184         if (!buf && !src)
 185                 return 1;
 186
 187         gather_stats(src, len, &stats);
 188
 189         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 190                 /*
 191                  * We're currently not going to even try to convert stuff
 192                  * that has bare CR characters. Does anybody do that crazy
 193                  * stuff?
 194                  */
 195                 if (stats.cr != stats.crlf)
 196                         return 0;
 197
 198                 /*
 199                  * And add some heuristics for binary vs text, of course...
 200                  */
 201                 if (is_binary(len, &stats))
 202                         return 0;
 203
 204                 if (crlf_action == CRLF_GUESS) {
 205                         /*
 206                          * If the file in the index has any CR in it, do not convert.
 207                          * This is the new safer autocrlf handling.
 208                          */
 209                         if (has_cr_in_index(path))
 210                                 return 0;
 211                 }
 212         }
 213
 214         check_safe_crlf(path, crlf_action, &stats, checksafe);
 215
 216         /* Optimization: No CR? Nothing to convert, regardless. */
 217         if (!stats.cr)
 218                 return 0;
 219
 220         /*
 221          * At this point all of our source analysis is done, and we are sure we
 222          * would convert. If we are in dry-run mode, we can give an answer.
 223          */
 224         if (!buf)
 225                 return 1;
 226
 227         /* only grow if not in place */
 228         if (strbuf_avail(buf) + buf->len < len)
 229                 strbuf_grow(buf, len - buf->len);
 230         dst = buf->buf;
 231         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 232                 /*
 233                  * If we guessed, we already know we rejected a file with
 234                  * lone CR, and we can strip a CR without looking at what
 235                  * follow it.
 236                  */
 237                 do {
 238                         unsigned char c = *src++;
 239                         if (c != '\r')
 240                                 *dst++ = c;
 241                 } while (--len);
 242         } else {
 243                 do {
 244                         unsigned char c = *src++;
 245                         if (! (c == '\r' && (1 < len && *src == '\n')))
 246                                 *dst++ = c;
 247                 } while (--len);
 248         }
 249         strbuf_setlen(buf, dst - buf->buf);
 250         return 1;
 251 }
 252
 253 static int crlf_to_worktree(const char *path, const char *src, size_t len,
 254                             struct strbuf *buf, enum crlf_action crlf_action)
 255 {
 256         char *to_free = NULL;
 257         struct text_stat stats;
 258
 259         if (!len || output_eol(crlf_action) != EOL_CRLF)
 260                 return 0;
 261
 262         gather_stats(src, len, &stats);
 263
 264         /* No LF? Nothing to convert, regardless. */
 265         if (!stats.lf)
 266                 return 0;
 267
 268         /* Was it already in CRLF format? */
 269         if (stats.lf == stats.crlf)
 270                 return 0;
 271
 272         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS) {
 273                 if (crlf_action == CRLF_GUESS) {
 274                         /* If we have any CR or CRLF line endings, we do not touch it */
 275                         /* This is the new safer autocrlf-handling */
 276                         if (stats.cr > 0 || stats.crlf > 0)
 277                                 return 0;
 278                 }
 279
 280                 /* If we have any bare CR characters, we're not going to touch it */
 281                 if (stats.cr != stats.crlf)
 282                         return 0;
 283
 284                 if (is_binary(len, &stats))
 285                         return 0;
 286         }
 287
 288         /* are we "faking" in place editing ? */
 289         if (src == buf->buf)
 290                 to_free = strbuf_detach(buf, NULL);
 291
 292         strbuf_grow(buf, len + stats.lf - stats.crlf);
 293         for (;;) {
 294                 const char *nl = memchr(src, '\n', len);
 295                 if (!nl)
 296                         break;
 297                 if (nl > src && nl[-1] == '\r') {
 298                         strbuf_add(buf, src, nl + 1 - src);
 299                 } else {
 300                         strbuf_add(buf, src, nl - src);
 301                         strbuf_addstr(buf, "\r\n");
 302                 }
 303                 len -= nl + 1 - src;
 304                 src  = nl + 1;
 305         }
 306         strbuf_add(buf, src, len);
 307
 308         free(to_free);
 309         return 1;
 310 }
 311
 312 struct filter_params {
 313         const char *src;
 314         unsigned long size;
 315         const char *cmd;
 316         const char *path;
 317 };
 318
 319 static int filter_buffer(int in, int out, void *data)
 320 {
 321         /*
 322          * Spawn cmd and feed the buffer contents through its stdin.
 323          */
 324         struct child_process child_process;
 325         struct filter_params *params = (struct filter_params *)data;
 326         int write_err, status;
 327         const char *argv[] = { NULL, NULL };
 328
 329         /* apply % substitution to cmd */
 330         struct strbuf cmd = STRBUF_INIT;
 331         struct strbuf path = STRBUF_INIT;
 332         struct strbuf_expand_dict_entry dict[] = {
 333                 { "f", NULL, },
 334                 { NULL, NULL, },
 335         };
 336
 337         /* quote the path to preserve spaces, etc. */
 338         sq_quote_buf(&path, params->path);
 339         dict[0].value = path.buf;
 340
 341         /* expand all %f with the quoted path */
 342         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 343         strbuf_release(&path);
 344
 345         argv[0] = cmd.buf;
 346
 347         memset(&child_process, 0, sizeof(child_process));
 348         child_process.argv = argv;
 349         child_process.use_shell = 1;
 350         child_process.in = -1;
 351         child_process.out = out;
 352
 353         if (start_command(&child_process))
 354                 return error("cannot fork to run external filter %s", params->cmd);
 355
 356         sigchain_push(SIGPIPE, SIG_IGN);
 357
 358         write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
 359         if (close(child_process.in))
 360                 write_err = 1;
 361         if (write_err)
 362                 error("cannot feed the input to external filter %s", params->cmd);
 363
 364         sigchain_pop(SIGPIPE);
 365
 366         status = finish_command(&child_process);
 367         if (status)
 368                 error("external filter %s failed %d", params->cmd, status);
 369
 370         strbuf_release(&cmd);
 371         return (write_err || status);
 372 }
 373
 374 static int apply_filter(const char *path, const char *src, size_t len,
 375                         struct strbuf *dst, const char *cmd)
 376 {
 377         /*
 378          * Create a pipeline to have the command filter the buffer's
 379          * contents.
 380          *
 381          * (child --> cmd) --> us
 382          */
 383         int ret = 1;
 384         struct strbuf nbuf = STRBUF_INIT;
 385         struct async async;
 386         struct filter_params params;
 387
 388         if (!cmd)
 389                 return 0;
 390
 391         if (!dst)
 392                 return 1;
 393
 394         memset(&async, 0, sizeof(async));
 395         async.proc = filter_buffer;
 396         async.data = &params;
 397         async.out = -1;
 398         params.src = src;
 399         params.size = len;
 400         params.cmd = cmd;
 401         params.path = path;
 402
 403         fflush(NULL);
 404         if (start_async(&async))
 405                 return 0;       /* error was already reported */
 406
 407         if (strbuf_read(&nbuf, async.out, len) < 0) {
 408                 error("read from external filter %s failed", cmd);
 409                 ret = 0;
 410         }
 411         if (close(async.out)) {
 412                 error("read from external filter %s failed", cmd);
 413                 ret = 0;
 414         }
 415         if (finish_async(&async)) {
 416                 error("external filter %s failed", cmd);
 417                 ret = 0;
 418         }
 419
 420         if (ret) {
 421                 strbuf_swap(dst, &nbuf);
 422         }
 423         strbuf_release(&nbuf);
 424         return ret;
 425 }
 426
 427 static struct convert_driver {
 428         const char *name;
 429         struct convert_driver *next;
 430         const char *smudge;
 431         const char *clean;
 432         int required;
 433 } *user_convert, **user_convert_tail;
 434
 435 static int read_convert_config(const char *var, const char *value, void *cb)
 436 {
 437         const char *ep, *name;
 438         int namelen;
 439         struct convert_driver *drv;
 440
 441         /*
 442          * External conversion drivers are configured using
 443          * "filter.<name>.variable".
 444          */
 445         if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
 446                 return 0;
 447         name = var + 7;
 448         namelen = ep - name;
 449         for (drv = user_convert; drv; drv = drv->next)
 450                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 451                         break;
 452         if (!drv) {
 453                 drv = xcalloc(1, sizeof(struct convert_driver));
 454                 drv->name = xmemdupz(name, namelen);
 455                 *user_convert_tail = drv;
 456                 user_convert_tail = &(drv->next);
 457         }
 458
 459         ep++;
 460
 461         /*
 462          * filter.<name>.smudge and filter.<name>.clean specifies
 463          * the command line:
 464          *
 465          *      command-line
 466          *
 467          * The command-line will not be interpolated in any way.
 468          */
 469
 470         if (!strcmp("smudge", ep))
 471                 return git_config_string(&drv->smudge, var, value);
 472
 473         if (!strcmp("clean", ep))
 474                 return git_config_string(&drv->clean, var, value);
 475
 476         if (!strcmp("required", ep)) {
 477                 drv->required = git_config_bool(var, value);
 478                 return 0;
 479         }
 480
 481         return 0;
 482 }
 483
 484 static int count_ident(const char *cp, unsigned long size)
 485 {
 486         /*
 487          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 488          */
 489         int cnt = 0;
 490         char ch;
 491
 492         while (size) {
 493                 ch = *cp++;
 494                 size--;
 495                 if (ch != '$')
 496                         continue;
 497                 if (size < 3)
 498                         break;
 499                 if (memcmp("Id", cp, 2))
 500                         continue;
 501                 ch = cp[2];
 502                 cp += 3;
 503                 size -= 3;
 504                 if (ch == '$')
 505                         cnt++; /* $Id$ */
 506                 if (ch != ':')
 507                         continue;
 508
 509                 /*
 510                  * "$Id: ... "; scan up to the closing dollar sign and discard.
 511                  */
 512                 while (size) {
 513                         ch = *cp++;
 514                         size--;
 515                         if (ch == '$') {
 516                                 cnt++;
 517                                 break;
 518                         }
 519                         if (ch == '\n')
 520                                 break;
 521                 }
 522         }
 523         return cnt;
 524 }
 525
 526 static int ident_to_git(const char *path, const char *src, size_t len,
 527                         struct strbuf *buf, int ident)
 528 {
 529         char *dst, *dollar;
 530
 531         if (!ident || (src && !count_ident(src, len)))
 532                 return 0;
 533
 534         if (!buf)
 535                 return 1;
 536
 537         /* only grow if not in place */
 538         if (strbuf_avail(buf) + buf->len < len)
 539                 strbuf_grow(buf, len - buf->len);
 540         dst = buf->buf;
 541         for (;;) {
 542                 dollar = memchr(src, '$', len);
 543                 if (!dollar)
 544                         break;
 545                 memmove(dst, src, dollar + 1 - src);
 546                 dst += dollar + 1 - src;
 547                 len -= dollar + 1 - src;
 548                 src  = dollar + 1;
 549
 550                 if (len > 3 && !memcmp(src, "Id:", 3)) {
 551                         dollar = memchr(src + 3, '$', len - 3);
 552                         if (!dollar)
 553                                 break;
 554                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 555                                 /* Line break before the next dollar. */
 556                                 continue;
 557                         }
 558
 559                         memcpy(dst, "Id$", 3);
 560                         dst += 3;
 561                         len -= dollar + 1 - src;
 562                         src  = dollar + 1;
 563                 }
 564         }
 565         memmove(dst, src, len);
 566         strbuf_setlen(buf, dst + len - buf->buf);
 567         return 1;
 568 }
 569
 570 static int ident_to_worktree(const char *path, const char *src, size_t len,
 571                              struct strbuf *buf, int ident)
 572 {
 573         unsigned char sha1[20];
 574         char *to_free = NULL, *dollar, *spc;
 575         int cnt;
 576
 577         if (!ident)
 578                 return 0;
 579
 580         cnt = count_ident(src, len);
 581         if (!cnt)
 582                 return 0;
 583
 584         /* are we "faking" in place editing ? */
 585         if (src == buf->buf)
 586                 to_free = strbuf_detach(buf, NULL);
 587         hash_sha1_file(src, len, "blob", sha1);
 588
 589         strbuf_grow(buf, len + cnt * 43);
 590         for (;;) {
 591                 /* step 1: run to the next '$' */
 592                 dollar = memchr(src, '$', len);
 593                 if (!dollar)
 594                         break;
 595                 strbuf_add(buf, src, dollar + 1 - src);
 596                 len -= dollar + 1 - src;
 597                 src  = dollar + 1;
 598
 599                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 600                 if (len < 3 || memcmp("Id", src, 2))
 601                         continue;
 602
 603                 /* step 3: skip over Id$ or Id:xxxxx$ */
 604                 if (src[2] == '$') {
 605                         src += 3;
 606                         len -= 3;
 607                 } else if (src[2] == ':') {
 608                         /*
 609                          * It's possible that an expanded Id has crept its way into the
 610                          * repository, we cope with that by stripping the expansion out.
 611                          * This is probably not a good idea, since it will cause changes
 612                          * on checkout, which won't go away by stash, but let's keep it
 613                          * for git-style ids.
 614                          */
 615                         dollar = memchr(src + 3, '$', len - 3);
 616                         if (!dollar) {
 617                                 /* incomplete keyword, no more '$', so just quit the loop */
 618                                 break;
 619                         }
 620
 621                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 622                                 /* Line break before the next dollar. */
 623                                 continue;
 624                         }
 625
 626                         spc = memchr(src + 4, ' ', dollar - src - 4);
 627                         if (spc && spc < dollar-1) {
 628                                 /* There are spaces in unexpected places.
 629                                  * This is probably an id from some other
 630                                  * versioning system. Keep it for now.
 631                                  */
 632                                 continue;
 633                         }
 634
 635                         len -= dollar + 1 - src;
 636                         src  = dollar + 1;
 637                 } else {
 638                         /* it wasn't a "Id$" or "Id:xxxx$" */
 639                         continue;
 640                 }
 641
 642                 /* step 4: substitute */
 643                 strbuf_addstr(buf, "Id: ");
 644                 strbuf_add(buf, sha1_to_hex(sha1), 40);
 645                 strbuf_addstr(buf, " $");
 646         }
 647         strbuf_add(buf, src, len);
 648
 649         free(to_free);
 650         return 1;
 651 }
 652
 653 static enum crlf_action git_path_check_crlf(const char *path, struct git_attr_check *check)
 654 {
 655         const char *value = check->value;
 656
 657         if (ATTR_TRUE(value))
 658                 return CRLF_TEXT;
 659         else if (ATTR_FALSE(value))
 660                 return CRLF_BINARY;
 661         else if (ATTR_UNSET(value))
 662                 ;
 663         else if (!strcmp(value, "input"))
 664                 return CRLF_INPUT;
 665         else if (!strcmp(value, "auto"))
 666                 return CRLF_AUTO;
 667         return CRLF_GUESS;
 668 }
 669
 670 static enum eol git_path_check_eol(const char *path, struct git_attr_check *check)
 671 {
 672         const char *value = check->value;
 673
 674         if (ATTR_UNSET(value))
 675                 ;
 676         else if (!strcmp(value, "lf"))
 677                 return EOL_LF;
 678         else if (!strcmp(value, "crlf"))
 679                 return EOL_CRLF;
 680         return EOL_UNSET;
 681 }
 682
 683 static struct convert_driver *git_path_check_convert(const char *path,
 684                                              struct git_attr_check *check)
 685 {
 686         const char *value = check->value;
 687         struct convert_driver *drv;
 688
 689         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 690                 return NULL;
 691         for (drv = user_convert; drv; drv = drv->next)
 692                 if (!strcmp(value, drv->name))
 693                         return drv;
 694         return NULL;
 695 }
 696
 697 static int git_path_check_ident(const char *path, struct git_attr_check *check)
 698 {
 699         const char *value = check->value;
 700
 701         return !!ATTR_TRUE(value);
 702 }
 703
 704 static enum crlf_action input_crlf_action(enum crlf_action text_attr, enum eol eol_attr)
 705 {
 706         if (text_attr == CRLF_BINARY)
 707                 return CRLF_BINARY;
 708         if (eol_attr == EOL_LF)
 709                 return CRLF_INPUT;
 710         if (eol_attr == EOL_CRLF)
 711                 return CRLF_CRLF;
 712         return text_attr;
 713 }
 714
 715 struct conv_attrs {
 716         struct convert_driver *drv;
 717         enum crlf_action crlf_action;
 718         enum eol eol_attr;
 719         int ident;
 720 };
 721
 722 static const char *conv_attr_name[] = {
 723         "crlf", "ident", "filter", "eol", "text",
 724 };
 725 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 726
 727 static void convert_attrs(struct conv_attrs *ca, const char *path)
 728 {
 729         int i;
 730         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 731
 732         if (!ccheck[0].attr) {
 733                 for (i = 0; i < NUM_CONV_ATTRS; i++)
 734                         ccheck[i].attr = git_attr(conv_attr_name[i]);
 735                 user_convert_tail = &user_convert;
 736                 git_config(read_convert_config, NULL);
 737         }
 738
 739         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 740                 ca->crlf_action = git_path_check_crlf(path, ccheck + 4);
 741                 if (ca->crlf_action == CRLF_GUESS)
 742                         ca->crlf_action = git_path_check_crlf(path, ccheck + 0);
 743                 ca->ident = git_path_check_ident(path, ccheck + 1);
 744                 ca->drv = git_path_check_convert(path, ccheck + 2);
 745                 ca->eol_attr = git_path_check_eol(path, ccheck + 3);
 746         } else {
 747                 ca->drv = NULL;
 748                 ca->crlf_action = CRLF_GUESS;
 749                 ca->eol_attr = EOL_UNSET;
 750                 ca->ident = 0;
 751         }
 752 }
 753
 754 int convert_to_git(const char *path, const char *src, size_t len,
 755                    struct strbuf *dst, enum safe_crlf checksafe)
 756 {
 757         int ret = 0;
 758         const char *filter = NULL;
 759         int required = 0;
 760         struct conv_attrs ca;
 761
 762         convert_attrs(&ca, path);
 763         if (ca.drv) {
 764                 filter = ca.drv->clean;
 765                 required = ca.drv->required;
 766         }
 767
 768         ret |= apply_filter(path, src, len, dst, filter);
 769         if (!ret && required)
 770                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 771
 772         if (ret && dst) {
 773                 src = dst->buf;
 774                 len = dst->len;
 775         }
 776         ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 777         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 778         if (ret && dst) {
 779                 src = dst->buf;
 780                 len = dst->len;
 781         }
 782         return ret | ident_to_git(path, src, len, dst, ca.ident);
 783 }
 784
 785 static int convert_to_working_tree_internal(const char *path, const char *src,
 786                                             size_t len, struct strbuf *dst,
 787                                             int normalizing)
 788 {
 789         int ret = 0, ret_filter = 0;
 790         const char *filter = NULL;
 791         int required = 0;
 792         struct conv_attrs ca;
 793
 794         convert_attrs(&ca, path);
 795         if (ca.drv) {
 796                 filter = ca.drv->smudge;
 797                 required = ca.drv->required;
 798         }
 799
 800         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 801         if (ret) {
 802                 src = dst->buf;
 803                 len = dst->len;
 804         }
 805         /*
 806          * CRLF conversion can be skipped if normalizing, unless there
 807          * is a smudge filter.  The filter might expect CRLFs.
 808          */
 809         if (filter || !normalizing) {
 810                 ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 811                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 812                 if (ret) {
 813                         src = dst->buf;
 814                         len = dst->len;
 815                 }
 816         }
 817
 818         ret_filter = apply_filter(path, src, len, dst, filter);
 819         if (!ret_filter && required)
 820                 die("%s: smudge filter %s failed", path, ca.drv->name);
 821
 822         return ret | ret_filter;
 823 }
 824
 825 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 826 {
 827         return convert_to_working_tree_internal(path, src, len, dst, 0);
 828 }
 829
 830 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 831 {
 832         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 833         if (ret) {
 834                 src = dst->buf;
 835                 len = dst->len;
 836         }
 837         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
 838 }
 839
 840 /*****************************************************************
 841  *
 842  * Streaming converison support
 843  *
 844  *****************************************************************/
 845
 846 typedef int (*filter_fn)(struct stream_filter *,
 847                          const char *input, size_t *isize_p,
 848                          char *output, size_t *osize_p);
 849 typedef void (*free_fn)(struct stream_filter *);
 850
 851 struct stream_filter_vtbl {
 852         filter_fn filter;
 853         free_fn free;
 854 };
 855
 856 struct stream_filter {
 857         struct stream_filter_vtbl *vtbl;
 858 };
 859
 860 static int null_filter_fn(struct stream_filter *filter,
 861                           const char *input, size_t *isize_p,
 862                           char *output, size_t *osize_p)
 863 {
 864         size_t count;
 865
 866         if (!input)
 867                 return 0; /* we do not keep any states */
 868         count = *isize_p;
 869         if (*osize_p < count)
 870                 count = *osize_p;
 871         if (count) {
 872                 memmove(output, input, count);
 873                 *isize_p -= count;
 874                 *osize_p -= count;
 875         }
 876         return 0;
 877 }
 878
 879 static void null_free_fn(struct stream_filter *filter)
 880 {
 881         ; /* nothing -- null instances are shared */
 882 }
 883
 884 static struct stream_filter_vtbl null_vtbl = {
 885         null_filter_fn,
 886         null_free_fn,
 887 };
 888
 889 static struct stream_filter null_filter_singleton = {
 890         &null_vtbl,
 891 };
 892
 893 int is_null_stream_filter(struct stream_filter *filter)
 894 {
 895         return filter == &null_filter_singleton;
 896 }
 897
 898
 899 /*
 900  * LF-to-CRLF filter
 901  */
 902
 903 struct lf_to_crlf_filter {
 904         struct stream_filter filter;
 905         unsigned has_held:1;
 906         char held;
 907 };
 908
 909 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
 910                                 const char *input, size_t *isize_p,
 911                                 char *output, size_t *osize_p)
 912 {
 913         size_t count, o = 0;
 914         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
 915
 916         /*
 917          * We may be holding onto the CR to see if it is followed by a
 918          * LF, in which case we would need to go to the main loop.
 919          * Otherwise, just emit it to the output stream.
 920          */
 921         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
 922                 output[o++] = lf_to_crlf->held;
 923                 lf_to_crlf->has_held = 0;
 924         }
 925
 926         /* We are told to drain */
 927         if (!input) {
 928                 *osize_p -= o;
 929                 return 0;
 930         }
 931
 932         count = *isize_p;
 933         if (count || lf_to_crlf->has_held) {
 934                 size_t i;
 935                 int was_cr = 0;
 936
 937                 if (lf_to_crlf->has_held) {
 938                         was_cr = 1;
 939                         lf_to_crlf->has_held = 0;
 940                 }
 941
 942                 for (i = 0; o < *osize_p && i < count; i++) {
 943                         char ch = input[i];
 944
 945                         if (ch == '\n') {
 946                                 output[o++] = '\r';
 947                         } else if (was_cr) {
 948                                 /*
 949                                  * Previous round saw CR and it is not followed
 950                                  * by a LF; emit the CR before processing the
 951                                  * current character.
 952                                  */
 953                                 output[o++] = '\r';
 954                         }
 955
 956                         /*
 957                          * We may have consumed the last output slot,
 958                          * in which case we need to break out of this
 959                          * loop; hold the current character before
 960                          * returning.
 961                          */
 962                         if (*osize_p <= o) {
 963                                 lf_to_crlf->has_held = 1;
 964                                 lf_to_crlf->held = ch;
 965                                 continue; /* break but increment i */
 966                         }
 967
 968                         if (ch == '\r') {
 969                                 was_cr = 1;
 970                                 continue;
 971                         }
 972
 973                         was_cr = 0;
 974                         output[o++] = ch;
 975                 }
 976
 977                 *osize_p -= o;
 978                 *isize_p -= i;
 979
 980                 if (!lf_to_crlf->has_held && was_cr) {
 981                         lf_to_crlf->has_held = 1;
 982                         lf_to_crlf->held = '\r';
 983                 }
 984         }
 985         return 0;
 986 }
 987
 988 static void lf_to_crlf_free_fn(struct stream_filter *filter)
 989 {
 990         free(filter);
 991 }
 992
 993 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
 994         lf_to_crlf_filter_fn,
 995         lf_to_crlf_free_fn,
 996 };
 997
 998 static struct stream_filter *lf_to_crlf_filter(void)
 999 {
1000         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1001
1002         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1003         return (struct stream_filter *)lf_to_crlf;
1004 }
1005
1006 /*
1007  * Cascade filter
1008  */
1009 #define FILTER_BUFFER 1024
1010 struct cascade_filter {
1011         struct stream_filter filter;
1012         struct stream_filter *one;
1013         struct stream_filter *two;
1014         char buf[FILTER_BUFFER];
1015         int end, ptr;
1016 };
1017
1018 static int cascade_filter_fn(struct stream_filter *filter,
1019                              const char *input, size_t *isize_p,
1020                              char *output, size_t *osize_p)
1021 {
1022         struct cascade_filter *cas = (struct cascade_filter *) filter;
1023         size_t filled = 0;
1024         size_t sz = *osize_p;
1025         size_t to_feed, remaining;
1026
1027         /*
1028          * input -- (one) --> buf -- (two) --> output
1029          */
1030         while (filled < sz) {
1031                 remaining = sz - filled;
1032
1033                 /* do we already have something to feed two with? */
1034                 if (cas->ptr < cas->end) {
1035                         to_feed = cas->end - cas->ptr;
1036                         if (stream_filter(cas->two,
1037                                           cas->buf + cas->ptr, &to_feed,
1038                                           output + filled, &remaining))
1039                                 return -1;
1040                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1041                         filled = sz - remaining;
1042                         continue;
1043                 }
1044
1045                 /* feed one from upstream and have it emit into our buffer */
1046                 to_feed = input ? *isize_p : 0;
1047                 if (input && !to_feed)
1048                         break;
1049                 remaining = sizeof(cas->buf);
1050                 if (stream_filter(cas->one,
1051                                   input, &to_feed,
1052                                   cas->buf, &remaining))
1053                         return -1;
1054                 cas->end = sizeof(cas->buf) - remaining;
1055                 cas->ptr = 0;
1056                 if (input) {
1057                         size_t fed = *isize_p - to_feed;
1058                         *isize_p -= fed;
1059                         input += fed;
1060                 }
1061
1062                 /* do we know that we drained one completely? */
1063                 if (input || cas->end)
1064                         continue;
1065
1066                 /* tell two to drain; we have nothing more to give it */
1067                 to_feed = 0;
1068                 remaining = sz - filled;
1069                 if (stream_filter(cas->two,
1070                                   NULL, &to_feed,
1071                                   output + filled, &remaining))
1072                         return -1;
1073                 if (remaining == (sz - filled))
1074                         break; /* completely drained two */
1075                 filled = sz - remaining;
1076         }
1077         *osize_p -= filled;
1078         return 0;
1079 }
1080
1081 static void cascade_free_fn(struct stream_filter *filter)
1082 {
1083         struct cascade_filter *cas = (struct cascade_filter *)filter;
1084         free_stream_filter(cas->one);
1085         free_stream_filter(cas->two);
1086         free(filter);
1087 }
1088
1089 static struct stream_filter_vtbl cascade_vtbl = {
1090         cascade_filter_fn,
1091         cascade_free_fn,
1092 };
1093
1094 static struct stream_filter *cascade_filter(struct stream_filter *one,
1095                                             struct stream_filter *two)
1096 {
1097         struct cascade_filter *cascade;
1098
1099         if (!one || is_null_stream_filter(one))
1100                 return two;
1101         if (!two || is_null_stream_filter(two))
1102                 return one;
1103
1104         cascade = xmalloc(sizeof(*cascade));
1105         cascade->one = one;
1106         cascade->two = two;
1107         cascade->end = cascade->ptr = 0;
1108         cascade->filter.vtbl = &cascade_vtbl;
1109         return (struct stream_filter *)cascade;
1110 }
1111
1112 /*
1113  * ident filter
1114  */
1115 #define IDENT_DRAINING (-1)
1116 #define IDENT_SKIPPING (-2)
1117 struct ident_filter {
1118         struct stream_filter filter;
1119         struct strbuf left;
1120         int state;
1121         char ident[45]; /* ": x40 $" */
1122 };
1123
1124 static int is_foreign_ident(const char *str)
1125 {
1126         int i;
1127
1128         if (prefixcmp(str, "$Id: "))
1129                 return 0;
1130         for (i = 5; str[i]; i++) {
1131                 if (isspace(str[i]) && str[i+1] != '$')
1132                         return 1;
1133         }
1134         return 0;
1135 }
1136
1137 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1138 {
1139         size_t to_drain = ident->left.len;
1140
1141         if (*osize_p < to_drain)
1142                 to_drain = *osize_p;
1143         if (to_drain) {
1144                 memcpy(*output_p, ident->left.buf, to_drain);
1145                 strbuf_remove(&ident->left, 0, to_drain);
1146                 *output_p += to_drain;
1147                 *osize_p -= to_drain;
1148         }
1149         if (!ident->left.len)
1150                 ident->state = 0;
1151 }
1152
1153 static int ident_filter_fn(struct stream_filter *filter,
1154                            const char *input, size_t *isize_p,
1155                            char *output, size_t *osize_p)
1156 {
1157         struct ident_filter *ident = (struct ident_filter *)filter;
1158         static const char head[] = "$Id";
1159
1160         if (!input) {
1161                 /* drain upon eof */
1162                 switch (ident->state) {
1163                 default:
1164                         strbuf_add(&ident->left, head, ident->state);
1165                 case IDENT_SKIPPING:
1166                         /* fallthru */
1167                 case IDENT_DRAINING:
1168                         ident_drain(ident, &output, osize_p);
1169                 }
1170                 return 0;
1171         }
1172
1173         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1174                 int ch;
1175
1176                 if (ident->state == IDENT_DRAINING) {
1177                         ident_drain(ident, &output, osize_p);
1178                         if (!*osize_p)
1179                                 break;
1180                         continue;
1181                 }
1182
1183                 ch = *(input++);
1184                 (*isize_p)--;
1185
1186                 if (ident->state == IDENT_SKIPPING) {
1187                         /*
1188                          * Skipping until '$' or LF, but keeping them
1189                          * in case it is a foreign ident.
1190                          */
1191                         strbuf_addch(&ident->left, ch);
1192                         if (ch != '\n' && ch != '$')
1193                                 continue;
1194                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1195                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1196                                 strbuf_addstr(&ident->left, ident->ident);
1197                         }
1198                         ident->state = IDENT_DRAINING;
1199                         continue;
1200                 }
1201
1202                 if (ident->state < sizeof(head) &&
1203                     head[ident->state] == ch) {
1204                         ident->state++;
1205                         continue;
1206                 }
1207
1208                 if (ident->state)
1209                         strbuf_add(&ident->left, head, ident->state);
1210                 if (ident->state == sizeof(head) - 1) {
1211                         if (ch != ':' && ch != '$') {
1212                                 strbuf_addch(&ident->left, ch);
1213                                 ident->state = 0;
1214                                 continue;
1215                         }
1216
1217                         if (ch == ':') {
1218                                 strbuf_addch(&ident->left, ch);
1219                                 ident->state = IDENT_SKIPPING;
1220                         } else {
1221                                 strbuf_addstr(&ident->left, ident->ident);
1222                                 ident->state = IDENT_DRAINING;
1223                         }
1224                         continue;
1225                 }
1226
1227                 strbuf_addch(&ident->left, ch);
1228                 ident->state = IDENT_DRAINING;
1229         }
1230         return 0;
1231 }
1232
1233 static void ident_free_fn(struct stream_filter *filter)
1234 {
1235         struct ident_filter *ident = (struct ident_filter *)filter;
1236         strbuf_release(&ident->left);
1237         free(filter);
1238 }
1239
1240 static struct stream_filter_vtbl ident_vtbl = {
1241         ident_filter_fn,
1242         ident_free_fn,
1243 };
1244
1245 static struct stream_filter *ident_filter(const unsigned char *sha1)
1246 {
1247         struct ident_filter *ident = xmalloc(sizeof(*ident));
1248
1249         sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
1250         strbuf_init(&ident->left, 0);
1251         ident->filter.vtbl = &ident_vtbl;
1252         ident->state = 0;
1253         return (struct stream_filter *)ident;
1254 }
1255
1256 /*
1257  * Return an appropriately constructed filter for the path, or NULL if
1258  * the contents cannot be filtered without reading the whole thing
1259  * in-core.
1260  *
1261  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1262  * large binary blob you would want us not to slurp into the memory!
1263  */
1264 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1265 {
1266         struct conv_attrs ca;
1267         enum crlf_action crlf_action;
1268         struct stream_filter *filter = NULL;
1269
1270         convert_attrs(&ca, path);
1271
1272         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1273                 return filter;
1274
1275         if (ca.ident)
1276                 filter = ident_filter(sha1);
1277
1278         crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
1279
1280         if ((crlf_action == CRLF_BINARY) || (crlf_action == CRLF_INPUT) ||
1281             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
1282                 filter = cascade_filter(filter, &null_filter_singleton);
1283
1284         else if (output_eol(crlf_action) == EOL_CRLF &&
1285                  !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
1286                 filter = cascade_filter(filter, lf_to_crlf_filter());
1287
1288         return filter;
1289 }
1290
1291 void free_stream_filter(struct stream_filter *filter)
1292 {
1293         filter->vtbl->free(filter);
1294 }
1295
1296 int stream_filter(struct stream_filter *filter,
1297                   const char *input, size_t *isize_p,
1298                   char *output, size_t *osize_p)
1299 {
1300         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1301 }