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