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         int fd;
 316         const char *cmd;
 317         const char *path;
 318 };
 319
 320 static int filter_buffer_or_fd(int in, int out, void *data)
 321 {
 322         /*
 323          * Spawn cmd and feed the buffer contents through its stdin.
 324          */
 325         struct child_process child_process;
 326         struct filter_params *params = (struct filter_params *)data;
 327         int write_err, status;
 328         const char *argv[] = { NULL, NULL };
 329
 330         /* apply % substitution to cmd */
 331         struct strbuf cmd = STRBUF_INIT;
 332         struct strbuf path = STRBUF_INIT;
 333         struct strbuf_expand_dict_entry dict[] = {
 334                 { "f", NULL, },
 335                 { NULL, NULL, },
 336         };
 337
 338         /* quote the path to preserve spaces, etc. */
 339         sq_quote_buf(&path, params->path);
 340         dict[0].value = path.buf;
 341
 342         /* expand all %f with the quoted path */
 343         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 344         strbuf_release(&path);
 345
 346         argv[0] = cmd.buf;
 347
 348         memset(&child_process, 0, sizeof(child_process));
 349         child_process.argv = argv;
 350         child_process.use_shell = 1;
 351         child_process.in = -1;
 352         child_process.out = out;
 353
 354         if (start_command(&child_process))
 355                 return error("cannot fork to run external filter %s", params->cmd);
 356
 357         sigchain_push(SIGPIPE, SIG_IGN);
 358
 359         if (params->src) {
 360                 write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
 361         } else {
 362                 write_err = copy_fd(params->fd, child_process.in);
 363         }
 364
 365         if (close(child_process.in))
 366                 write_err = 1;
 367         if (write_err)
 368                 error("cannot feed the input to external filter %s", params->cmd);
 369
 370         sigchain_pop(SIGPIPE);
 371
 372         status = finish_command(&child_process);
 373         if (status)
 374                 error("external filter %s failed %d", params->cmd, status);
 375
 376         strbuf_release(&cmd);
 377         return (write_err || status);
 378 }
 379
 380 static int apply_filter(const char *path, const char *src, size_t len, int fd,
 381                         struct strbuf *dst, const char *cmd)
 382 {
 383         /*
 384          * Create a pipeline to have the command filter the buffer's
 385          * contents.
 386          *
 387          * (child --> cmd) --> us
 388          */
 389         int ret = 1;
 390         struct strbuf nbuf = STRBUF_INIT;
 391         struct async async;
 392         struct filter_params params;
 393
 394         if (!cmd)
 395                 return 0;
 396
 397         if (!dst)
 398                 return 1;
 399
 400         memset(&async, 0, sizeof(async));
 401         async.proc = filter_buffer_or_fd;
 402         async.data = &params;
 403         async.out = -1;
 404         params.src = src;
 405         params.size = len;
 406         params.fd = fd;
 407         params.cmd = cmd;
 408         params.path = path;
 409
 410         fflush(NULL);
 411         if (start_async(&async))
 412                 return 0;       /* error was already reported */
 413
 414         if (strbuf_read(&nbuf, async.out, len) < 0) {
 415                 error("read from external filter %s failed", cmd);
 416                 ret = 0;
 417         }
 418         if (close(async.out)) {
 419                 error("read from external filter %s failed", cmd);
 420                 ret = 0;
 421         }
 422         if (finish_async(&async)) {
 423                 error("external filter %s failed", cmd);
 424                 ret = 0;
 425         }
 426
 427         if (ret) {
 428                 strbuf_swap(dst, &nbuf);
 429         }
 430         strbuf_release(&nbuf);
 431         return ret;
 432 }
 433
 434 static struct convert_driver {
 435         const char *name;
 436         struct convert_driver *next;
 437         const char *smudge;
 438         const char *clean;
 439         int required;
 440 } *user_convert, **user_convert_tail;
 441
 442 static int read_convert_config(const char *var, const char *value, void *cb)
 443 {
 444         const char *key, *name;
 445         int namelen;
 446         struct convert_driver *drv;
 447
 448         /*
 449          * External conversion drivers are configured using
 450          * "filter.<name>.variable".
 451          */
 452         if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 453                 return 0;
 454         for (drv = user_convert; drv; drv = drv->next)
 455                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 456                         break;
 457         if (!drv) {
 458                 drv = xcalloc(1, sizeof(struct convert_driver));
 459                 drv->name = xmemdupz(name, namelen);
 460                 *user_convert_tail = drv;
 461                 user_convert_tail = &(drv->next);
 462         }
 463
 464         /*
 465          * filter.<name>.smudge and filter.<name>.clean specifies
 466          * the command line:
 467          *
 468          *      command-line
 469          *
 470          * The command-line will not be interpolated in any way.
 471          */
 472
 473         if (!strcmp("smudge", key))
 474                 return git_config_string(&drv->smudge, var, value);
 475
 476         if (!strcmp("clean", key))
 477                 return git_config_string(&drv->clean, var, value);
 478
 479         if (!strcmp("required", key)) {
 480                 drv->required = git_config_bool(var, value);
 481                 return 0;
 482         }
 483
 484         return 0;
 485 }
 486
 487 static int count_ident(const char *cp, unsigned long size)
 488 {
 489         /*
 490          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 491          */
 492         int cnt = 0;
 493         char ch;
 494
 495         while (size) {
 496                 ch = *cp++;
 497                 size--;
 498                 if (ch != '$')
 499                         continue;
 500                 if (size < 3)
 501                         break;
 502                 if (memcmp("Id", cp, 2))
 503                         continue;
 504                 ch = cp[2];
 505                 cp += 3;
 506                 size -= 3;
 507                 if (ch == '$')
 508                         cnt++; /* $Id$ */
 509                 if (ch != ':')
 510                         continue;
 511
 512                 /*
 513                  * "$Id: ... "; scan up to the closing dollar sign and discard.
 514                  */
 515                 while (size) {
 516                         ch = *cp++;
 517                         size--;
 518                         if (ch == '$') {
 519                                 cnt++;
 520                                 break;
 521                         }
 522                         if (ch == '\n')
 523                                 break;
 524                 }
 525         }
 526         return cnt;
 527 }
 528
 529 static int ident_to_git(const char *path, const char *src, size_t len,
 530                         struct strbuf *buf, int ident)
 531 {
 532         char *dst, *dollar;
 533
 534         if (!ident || (src && !count_ident(src, len)))
 535                 return 0;
 536
 537         if (!buf)
 538                 return 1;
 539
 540         /* only grow if not in place */
 541         if (strbuf_avail(buf) + buf->len < len)
 542                 strbuf_grow(buf, len - buf->len);
 543         dst = buf->buf;
 544         for (;;) {
 545                 dollar = memchr(src, '$', len);
 546                 if (!dollar)
 547                         break;
 548                 memmove(dst, src, dollar + 1 - src);
 549                 dst += dollar + 1 - src;
 550                 len -= dollar + 1 - src;
 551                 src  = dollar + 1;
 552
 553                 if (len > 3 && !memcmp(src, "Id:", 3)) {
 554                         dollar = memchr(src + 3, '$', len - 3);
 555                         if (!dollar)
 556                                 break;
 557                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 558                                 /* Line break before the next dollar. */
 559                                 continue;
 560                         }
 561
 562                         memcpy(dst, "Id$", 3);
 563                         dst += 3;
 564                         len -= dollar + 1 - src;
 565                         src  = dollar + 1;
 566                 }
 567         }
 568         memmove(dst, src, len);
 569         strbuf_setlen(buf, dst + len - buf->buf);
 570         return 1;
 571 }
 572
 573 static int ident_to_worktree(const char *path, const char *src, size_t len,
 574                              struct strbuf *buf, int ident)
 575 {
 576         unsigned char sha1[20];
 577         char *to_free = NULL, *dollar, *spc;
 578         int cnt;
 579
 580         if (!ident)
 581                 return 0;
 582
 583         cnt = count_ident(src, len);
 584         if (!cnt)
 585                 return 0;
 586
 587         /* are we "faking" in place editing ? */
 588         if (src == buf->buf)
 589                 to_free = strbuf_detach(buf, NULL);
 590         hash_sha1_file(src, len, "blob", sha1);
 591
 592         strbuf_grow(buf, len + cnt * 43);
 593         for (;;) {
 594                 /* step 1: run to the next '$' */
 595                 dollar = memchr(src, '$', len);
 596                 if (!dollar)
 597                         break;
 598                 strbuf_add(buf, src, dollar + 1 - src);
 599                 len -= dollar + 1 - src;
 600                 src  = dollar + 1;
 601
 602                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 603                 if (len < 3 || memcmp("Id", src, 2))
 604                         continue;
 605
 606                 /* step 3: skip over Id$ or Id:xxxxx$ */
 607                 if (src[2] == '$') {
 608                         src += 3;
 609                         len -= 3;
 610                 } else if (src[2] == ':') {
 611                         /*
 612                          * It's possible that an expanded Id has crept its way into the
 613                          * repository, we cope with that by stripping the expansion out.
 614                          * This is probably not a good idea, since it will cause changes
 615                          * on checkout, which won't go away by stash, but let's keep it
 616                          * for git-style ids.
 617                          */
 618                         dollar = memchr(src + 3, '$', len - 3);
 619                         if (!dollar) {
 620                                 /* incomplete keyword, no more '$', so just quit the loop */
 621                                 break;
 622                         }
 623
 624                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 625                                 /* Line break before the next dollar. */
 626                                 continue;
 627                         }
 628
 629                         spc = memchr(src + 4, ' ', dollar - src - 4);
 630                         if (spc && spc < dollar-1) {
 631                                 /* There are spaces in unexpected places.
 632                                  * This is probably an id from some other
 633                                  * versioning system. Keep it for now.
 634                                  */
 635                                 continue;
 636                         }
 637
 638                         len -= dollar + 1 - src;
 639                         src  = dollar + 1;
 640                 } else {
 641                         /* it wasn't a "Id$" or "Id:xxxx$" */
 642                         continue;
 643                 }
 644
 645                 /* step 4: substitute */
 646                 strbuf_addstr(buf, "Id: ");
 647                 strbuf_add(buf, sha1_to_hex(sha1), 40);
 648                 strbuf_addstr(buf, " $");
 649         }
 650         strbuf_add(buf, src, len);
 651
 652         free(to_free);
 653         return 1;
 654 }
 655
 656 static enum crlf_action git_path_check_crlf(const char *path, struct git_attr_check *check)
 657 {
 658         const char *value = check->value;
 659
 660         if (ATTR_TRUE(value))
 661                 return CRLF_TEXT;
 662         else if (ATTR_FALSE(value))
 663                 return CRLF_BINARY;
 664         else if (ATTR_UNSET(value))
 665                 ;
 666         else if (!strcmp(value, "input"))
 667                 return CRLF_INPUT;
 668         else if (!strcmp(value, "auto"))
 669                 return CRLF_AUTO;
 670         return CRLF_GUESS;
 671 }
 672
 673 static enum eol git_path_check_eol(const char *path, struct git_attr_check *check)
 674 {
 675         const char *value = check->value;
 676
 677         if (ATTR_UNSET(value))
 678                 ;
 679         else if (!strcmp(value, "lf"))
 680                 return EOL_LF;
 681         else if (!strcmp(value, "crlf"))
 682                 return EOL_CRLF;
 683         return EOL_UNSET;
 684 }
 685
 686 static struct convert_driver *git_path_check_convert(const char *path,
 687                                              struct git_attr_check *check)
 688 {
 689         const char *value = check->value;
 690         struct convert_driver *drv;
 691
 692         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 693                 return NULL;
 694         for (drv = user_convert; drv; drv = drv->next)
 695                 if (!strcmp(value, drv->name))
 696                         return drv;
 697         return NULL;
 698 }
 699
 700 static int git_path_check_ident(const char *path, struct git_attr_check *check)
 701 {
 702         const char *value = check->value;
 703
 704         return !!ATTR_TRUE(value);
 705 }
 706
 707 static enum crlf_action input_crlf_action(enum crlf_action text_attr, enum eol eol_attr)
 708 {
 709         if (text_attr == CRLF_BINARY)
 710                 return CRLF_BINARY;
 711         if (eol_attr == EOL_LF)
 712                 return CRLF_INPUT;
 713         if (eol_attr == EOL_CRLF)
 714                 return CRLF_CRLF;
 715         return text_attr;
 716 }
 717
 718 struct conv_attrs {
 719         struct convert_driver *drv;
 720         enum crlf_action crlf_action;
 721         enum eol eol_attr;
 722         int ident;
 723 };
 724
 725 static const char *conv_attr_name[] = {
 726         "crlf", "ident", "filter", "eol", "text",
 727 };
 728 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 729
 730 static void convert_attrs(struct conv_attrs *ca, const char *path)
 731 {
 732         int i;
 733         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 734
 735         if (!ccheck[0].attr) {
 736                 for (i = 0; i < NUM_CONV_ATTRS; i++)
 737                         ccheck[i].attr = git_attr(conv_attr_name[i]);
 738                 user_convert_tail = &user_convert;
 739                 git_config(read_convert_config, NULL);
 740         }
 741
 742         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 743                 ca->crlf_action = git_path_check_crlf(path, ccheck + 4);
 744                 if (ca->crlf_action == CRLF_GUESS)
 745                         ca->crlf_action = git_path_check_crlf(path, ccheck + 0);
 746                 ca->ident = git_path_check_ident(path, ccheck + 1);
 747                 ca->drv = git_path_check_convert(path, ccheck + 2);
 748                 ca->eol_attr = git_path_check_eol(path, ccheck + 3);
 749         } else {
 750                 ca->drv = NULL;
 751                 ca->crlf_action = CRLF_GUESS;
 752                 ca->eol_attr = EOL_UNSET;
 753                 ca->ident = 0;
 754         }
 755 }
 756
 757 int would_convert_to_git_filter_fd(const char *path)
 758 {
 759         struct conv_attrs ca;
 760
 761         convert_attrs(&ca, path);
 762         if (!ca.drv)
 763                 return 0;
 764
 765         /*
 766          * Apply a filter to an fd only if the filter is required to succeed.
 767          * We must die if the filter fails, because the original data before
 768          * filtering is not available.
 769          */
 770         if (!ca.drv->required)
 771                 return 0;
 772
 773         return apply_filter(path, NULL, 0, -1, NULL, ca.drv->clean);
 774 }
 775
 776 int convert_to_git(const char *path, const char *src, size_t len,
 777                    struct strbuf *dst, enum safe_crlf checksafe)
 778 {
 779         int ret = 0;
 780         const char *filter = NULL;
 781         int required = 0;
 782         struct conv_attrs ca;
 783
 784         convert_attrs(&ca, path);
 785         if (ca.drv) {
 786                 filter = ca.drv->clean;
 787                 required = ca.drv->required;
 788         }
 789
 790         ret |= apply_filter(path, src, len, -1, dst, filter);
 791         if (!ret && required)
 792                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 793
 794         if (ret && dst) {
 795                 src = dst->buf;
 796                 len = dst->len;
 797         }
 798         ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 799         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 800         if (ret && dst) {
 801                 src = dst->buf;
 802                 len = dst->len;
 803         }
 804         return ret | ident_to_git(path, src, len, dst, ca.ident);
 805 }
 806
 807 void convert_to_git_filter_fd(const char *path, int fd, struct strbuf *dst,
 808                               enum safe_crlf checksafe)
 809 {
 810         struct conv_attrs ca;
 811         convert_attrs(&ca, path);
 812
 813         assert(ca.drv);
 814         assert(ca.drv->clean);
 815
 816         if (!apply_filter(path, NULL, 0, fd, dst, ca.drv->clean))
 817                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 818
 819         ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 820         crlf_to_git(path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
 821         ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
 822 }
 823
 824 static int convert_to_working_tree_internal(const char *path, const char *src,
 825                                             size_t len, struct strbuf *dst,
 826                                             int normalizing)
 827 {
 828         int ret = 0, ret_filter = 0;
 829         const char *filter = NULL;
 830         int required = 0;
 831         struct conv_attrs ca;
 832
 833         convert_attrs(&ca, path);
 834         if (ca.drv) {
 835                 filter = ca.drv->smudge;
 836                 required = ca.drv->required;
 837         }
 838
 839         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 840         if (ret) {
 841                 src = dst->buf;
 842                 len = dst->len;
 843         }
 844         /*
 845          * CRLF conversion can be skipped if normalizing, unless there
 846          * is a smudge filter.  The filter might expect CRLFs.
 847          */
 848         if (filter || !normalizing) {
 849                 ca.crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
 850                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 851                 if (ret) {
 852                         src = dst->buf;
 853                         len = dst->len;
 854                 }
 855         }
 856
 857         ret_filter = apply_filter(path, src, len, -1, dst, filter);
 858         if (!ret_filter && required)
 859                 die("%s: smudge filter %s failed", path, ca.drv->name);
 860
 861         return ret | ret_filter;
 862 }
 863
 864 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 865 {
 866         return convert_to_working_tree_internal(path, src, len, dst, 0);
 867 }
 868
 869 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 870 {
 871         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 872         if (ret) {
 873                 src = dst->buf;
 874                 len = dst->len;
 875         }
 876         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_FALSE);
 877 }
 878
 879 /*****************************************************************
 880  *
 881  * Streaming conversion support
 882  *
 883  *****************************************************************/
 884
 885 typedef int (*filter_fn)(struct stream_filter *,
 886                          const char *input, size_t *isize_p,
 887                          char *output, size_t *osize_p);
 888 typedef void (*free_fn)(struct stream_filter *);
 889
 890 struct stream_filter_vtbl {
 891         filter_fn filter;
 892         free_fn free;
 893 };
 894
 895 struct stream_filter {
 896         struct stream_filter_vtbl *vtbl;
 897 };
 898
 899 static int null_filter_fn(struct stream_filter *filter,
 900                           const char *input, size_t *isize_p,
 901                           char *output, size_t *osize_p)
 902 {
 903         size_t count;
 904
 905         if (!input)
 906                 return 0; /* we do not keep any states */
 907         count = *isize_p;
 908         if (*osize_p < count)
 909                 count = *osize_p;
 910         if (count) {
 911                 memmove(output, input, count);
 912                 *isize_p -= count;
 913                 *osize_p -= count;
 914         }
 915         return 0;
 916 }
 917
 918 static void null_free_fn(struct stream_filter *filter)
 919 {
 920         ; /* nothing -- null instances are shared */
 921 }
 922
 923 static struct stream_filter_vtbl null_vtbl = {
 924         null_filter_fn,
 925         null_free_fn,
 926 };
 927
 928 static struct stream_filter null_filter_singleton = {
 929         &null_vtbl,
 930 };
 931
 932 int is_null_stream_filter(struct stream_filter *filter)
 933 {
 934         return filter == &null_filter_singleton;
 935 }
 936
 937
 938 /*
 939  * LF-to-CRLF filter
 940  */
 941
 942 struct lf_to_crlf_filter {
 943         struct stream_filter filter;
 944         unsigned has_held:1;
 945         char held;
 946 };
 947
 948 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
 949                                 const char *input, size_t *isize_p,
 950                                 char *output, size_t *osize_p)
 951 {
 952         size_t count, o = 0;
 953         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
 954
 955         /*
 956          * We may be holding onto the CR to see if it is followed by a
 957          * LF, in which case we would need to go to the main loop.
 958          * Otherwise, just emit it to the output stream.
 959          */
 960         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
 961                 output[o++] = lf_to_crlf->held;
 962                 lf_to_crlf->has_held = 0;
 963         }
 964
 965         /* We are told to drain */
 966         if (!input) {
 967                 *osize_p -= o;
 968                 return 0;
 969         }
 970
 971         count = *isize_p;
 972         if (count || lf_to_crlf->has_held) {
 973                 size_t i;
 974                 int was_cr = 0;
 975
 976                 if (lf_to_crlf->has_held) {
 977                         was_cr = 1;
 978                         lf_to_crlf->has_held = 0;
 979                 }
 980
 981                 for (i = 0; o < *osize_p && i < count; i++) {
 982                         char ch = input[i];
 983
 984                         if (ch == '\n') {
 985                                 output[o++] = '\r';
 986                         } else if (was_cr) {
 987                                 /*
 988                                  * Previous round saw CR and it is not followed
 989                                  * by a LF; emit the CR before processing the
 990                                  * current character.
 991                                  */
 992                                 output[o++] = '\r';
 993                         }
 994
 995                         /*
 996                          * We may have consumed the last output slot,
 997                          * in which case we need to break out of this
 998                          * loop; hold the current character before
 999                          * returning.
1000                          */
1001                         if (*osize_p <= o) {
1002                                 lf_to_crlf->has_held = 1;
1003                                 lf_to_crlf->held = ch;
1004                                 continue; /* break but increment i */
1005                         }
1006
1007                         if (ch == '\r') {
1008                                 was_cr = 1;
1009                                 continue;
1010                         }
1011
1012                         was_cr = 0;
1013                         output[o++] = ch;
1014                 }
1015
1016                 *osize_p -= o;
1017                 *isize_p -= i;
1018
1019                 if (!lf_to_crlf->has_held && was_cr) {
1020                         lf_to_crlf->has_held = 1;
1021                         lf_to_crlf->held = '\r';
1022                 }
1023         }
1024         return 0;
1025 }
1026
1027 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1028 {
1029         free(filter);
1030 }
1031
1032 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1033         lf_to_crlf_filter_fn,
1034         lf_to_crlf_free_fn,
1035 };
1036
1037 static struct stream_filter *lf_to_crlf_filter(void)
1038 {
1039         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1040
1041         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1042         return (struct stream_filter *)lf_to_crlf;
1043 }
1044
1045 /*
1046  * Cascade filter
1047  */
1048 #define FILTER_BUFFER 1024
1049 struct cascade_filter {
1050         struct stream_filter filter;
1051         struct stream_filter *one;
1052         struct stream_filter *two;
1053         char buf[FILTER_BUFFER];
1054         int end, ptr;
1055 };
1056
1057 static int cascade_filter_fn(struct stream_filter *filter,
1058                              const char *input, size_t *isize_p,
1059                              char *output, size_t *osize_p)
1060 {
1061         struct cascade_filter *cas = (struct cascade_filter *) filter;
1062         size_t filled = 0;
1063         size_t sz = *osize_p;
1064         size_t to_feed, remaining;
1065
1066         /*
1067          * input -- (one) --> buf -- (two) --> output
1068          */
1069         while (filled < sz) {
1070                 remaining = sz - filled;
1071
1072                 /* do we already have something to feed two with? */
1073                 if (cas->ptr < cas->end) {
1074                         to_feed = cas->end - cas->ptr;
1075                         if (stream_filter(cas->two,
1076                                           cas->buf + cas->ptr, &to_feed,
1077                                           output + filled, &remaining))
1078                                 return -1;
1079                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1080                         filled = sz - remaining;
1081                         continue;
1082                 }
1083
1084                 /* feed one from upstream and have it emit into our buffer */
1085                 to_feed = input ? *isize_p : 0;
1086                 if (input && !to_feed)
1087                         break;
1088                 remaining = sizeof(cas->buf);
1089                 if (stream_filter(cas->one,
1090                                   input, &to_feed,
1091                                   cas->buf, &remaining))
1092                         return -1;
1093                 cas->end = sizeof(cas->buf) - remaining;
1094                 cas->ptr = 0;
1095                 if (input) {
1096                         size_t fed = *isize_p - to_feed;
1097                         *isize_p -= fed;
1098                         input += fed;
1099                 }
1100
1101                 /* do we know that we drained one completely? */
1102                 if (input || cas->end)
1103                         continue;
1104
1105                 /* tell two to drain; we have nothing more to give it */
1106                 to_feed = 0;
1107                 remaining = sz - filled;
1108                 if (stream_filter(cas->two,
1109                                   NULL, &to_feed,
1110                                   output + filled, &remaining))
1111                         return -1;
1112                 if (remaining == (sz - filled))
1113                         break; /* completely drained two */
1114                 filled = sz - remaining;
1115         }
1116         *osize_p -= filled;
1117         return 0;
1118 }
1119
1120 static void cascade_free_fn(struct stream_filter *filter)
1121 {
1122         struct cascade_filter *cas = (struct cascade_filter *)filter;
1123         free_stream_filter(cas->one);
1124         free_stream_filter(cas->two);
1125         free(filter);
1126 }
1127
1128 static struct stream_filter_vtbl cascade_vtbl = {
1129         cascade_filter_fn,
1130         cascade_free_fn,
1131 };
1132
1133 static struct stream_filter *cascade_filter(struct stream_filter *one,
1134                                             struct stream_filter *two)
1135 {
1136         struct cascade_filter *cascade;
1137
1138         if (!one || is_null_stream_filter(one))
1139                 return two;
1140         if (!two || is_null_stream_filter(two))
1141                 return one;
1142
1143         cascade = xmalloc(sizeof(*cascade));
1144         cascade->one = one;
1145         cascade->two = two;
1146         cascade->end = cascade->ptr = 0;
1147         cascade->filter.vtbl = &cascade_vtbl;
1148         return (struct stream_filter *)cascade;
1149 }
1150
1151 /*
1152  * ident filter
1153  */
1154 #define IDENT_DRAINING (-1)
1155 #define IDENT_SKIPPING (-2)
1156 struct ident_filter {
1157         struct stream_filter filter;
1158         struct strbuf left;
1159         int state;
1160         char ident[45]; /* ": x40 $" */
1161 };
1162
1163 static int is_foreign_ident(const char *str)
1164 {
1165         int i;
1166
1167         if (!skip_prefix(str, "$Id: ", &str))
1168                 return 0;
1169         for (i = 0; str[i]; i++) {
1170                 if (isspace(str[i]) && str[i+1] != '$')
1171                         return 1;
1172         }
1173         return 0;
1174 }
1175
1176 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1177 {
1178         size_t to_drain = ident->left.len;
1179
1180         if (*osize_p < to_drain)
1181                 to_drain = *osize_p;
1182         if (to_drain) {
1183                 memcpy(*output_p, ident->left.buf, to_drain);
1184                 strbuf_remove(&ident->left, 0, to_drain);
1185                 *output_p += to_drain;
1186                 *osize_p -= to_drain;
1187         }
1188         if (!ident->left.len)
1189                 ident->state = 0;
1190 }
1191
1192 static int ident_filter_fn(struct stream_filter *filter,
1193                            const char *input, size_t *isize_p,
1194                            char *output, size_t *osize_p)
1195 {
1196         struct ident_filter *ident = (struct ident_filter *)filter;
1197         static const char head[] = "$Id";
1198
1199         if (!input) {
1200                 /* drain upon eof */
1201                 switch (ident->state) {
1202                 default:
1203                         strbuf_add(&ident->left, head, ident->state);
1204                 case IDENT_SKIPPING:
1205                         /* fallthru */
1206                 case IDENT_DRAINING:
1207                         ident_drain(ident, &output, osize_p);
1208                 }
1209                 return 0;
1210         }
1211
1212         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1213                 int ch;
1214
1215                 if (ident->state == IDENT_DRAINING) {
1216                         ident_drain(ident, &output, osize_p);
1217                         if (!*osize_p)
1218                                 break;
1219                         continue;
1220                 }
1221
1222                 ch = *(input++);
1223                 (*isize_p)--;
1224
1225                 if (ident->state == IDENT_SKIPPING) {
1226                         /*
1227                          * Skipping until '$' or LF, but keeping them
1228                          * in case it is a foreign ident.
1229                          */
1230                         strbuf_addch(&ident->left, ch);
1231                         if (ch != '\n' && ch != '$')
1232                                 continue;
1233                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1234                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1235                                 strbuf_addstr(&ident->left, ident->ident);
1236                         }
1237                         ident->state = IDENT_DRAINING;
1238                         continue;
1239                 }
1240
1241                 if (ident->state < sizeof(head) &&
1242                     head[ident->state] == ch) {
1243                         ident->state++;
1244                         continue;
1245                 }
1246
1247                 if (ident->state)
1248                         strbuf_add(&ident->left, head, ident->state);
1249                 if (ident->state == sizeof(head) - 1) {
1250                         if (ch != ':' && ch != '$') {
1251                                 strbuf_addch(&ident->left, ch);
1252                                 ident->state = 0;
1253                                 continue;
1254                         }
1255
1256                         if (ch == ':') {
1257                                 strbuf_addch(&ident->left, ch);
1258                                 ident->state = IDENT_SKIPPING;
1259                         } else {
1260                                 strbuf_addstr(&ident->left, ident->ident);
1261                                 ident->state = IDENT_DRAINING;
1262                         }
1263                         continue;
1264                 }
1265
1266                 strbuf_addch(&ident->left, ch);
1267                 ident->state = IDENT_DRAINING;
1268         }
1269         return 0;
1270 }
1271
1272 static void ident_free_fn(struct stream_filter *filter)
1273 {
1274         struct ident_filter *ident = (struct ident_filter *)filter;
1275         strbuf_release(&ident->left);
1276         free(filter);
1277 }
1278
1279 static struct stream_filter_vtbl ident_vtbl = {
1280         ident_filter_fn,
1281         ident_free_fn,
1282 };
1283
1284 static struct stream_filter *ident_filter(const unsigned char *sha1)
1285 {
1286         struct ident_filter *ident = xmalloc(sizeof(*ident));
1287
1288         sprintf(ident->ident, ": %s $", sha1_to_hex(sha1));
1289         strbuf_init(&ident->left, 0);
1290         ident->filter.vtbl = &ident_vtbl;
1291         ident->state = 0;
1292         return (struct stream_filter *)ident;
1293 }
1294
1295 /*
1296  * Return an appropriately constructed filter for the path, or NULL if
1297  * the contents cannot be filtered without reading the whole thing
1298  * in-core.
1299  *
1300  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1301  * large binary blob you would want us not to slurp into the memory!
1302  */
1303 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1304 {
1305         struct conv_attrs ca;
1306         enum crlf_action crlf_action;
1307         struct stream_filter *filter = NULL;
1308
1309         convert_attrs(&ca, path);
1310
1311         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1312                 return filter;
1313
1314         if (ca.ident)
1315                 filter = ident_filter(sha1);
1316
1317         crlf_action = input_crlf_action(ca.crlf_action, ca.eol_attr);
1318
1319         if ((crlf_action == CRLF_BINARY) || (crlf_action == CRLF_INPUT) ||
1320             (crlf_action == CRLF_GUESS && auto_crlf == AUTO_CRLF_FALSE))
1321                 filter = cascade_filter(filter, &null_filter_singleton);
1322
1323         else if (output_eol(crlf_action) == EOL_CRLF &&
1324                  !(crlf_action == CRLF_AUTO || crlf_action == CRLF_GUESS))
1325                 filter = cascade_filter(filter, lf_to_crlf_filter());
1326
1327         return filter;
1328 }
1329
1330 void free_stream_filter(struct stream_filter *filter)
1331 {
1332         filter->vtbl->free(filter);
1333 }
1334
1335 int stream_filter(struct stream_filter *filter,
1336                   const char *input, size_t *isize_p,
1337                   char *output, size_t *osize_p)
1338 {
1339         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1340 }