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