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 /* Stat bits: When BIN is set, the txt bits are unset */
  17 #define CONVERT_STAT_BITS_TXT_LF    0x1
  18 #define CONVERT_STAT_BITS_TXT_CRLF  0x2
  19 #define CONVERT_STAT_BITS_BIN       0x4
  20
  21 enum crlf_action {
  22         CRLF_UNDEFINED,
  23         CRLF_BINARY,
  24         CRLF_TEXT,
  25         CRLF_TEXT_INPUT,
  26         CRLF_TEXT_CRLF,
  27         CRLF_AUTO,
  28         CRLF_AUTO_INPUT,
  29         CRLF_AUTO_CRLF
  30 };
  31
  32 struct text_stat {
  33         /* NUL, CR, LF and CRLF counts */
  34         unsigned nul, lonecr, lonelf, crlf;
  35
  36         /* These are just approximations! */
  37         unsigned printable, nonprintable;
  38 };
  39
  40 static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  41 {
  42         unsigned long i;
  43
  44         memset(stats, 0, sizeof(*stats));
  45
  46         for (i = 0; i < size; i++) {
  47                 unsigned char c = buf[i];
  48                 if (c == '\r') {
  49                         if (i+1 < size && buf[i+1] == '\n') {
  50                                 stats->crlf++;
  51                                 i++;
  52                         } else
  53                                 stats->lonecr++;
  54                         continue;
  55                 }
  56                 if (c == '\n') {
  57                         stats->lonelf++;
  58                         continue;
  59                 }
  60                 if (c == 127)
  61                         /* DEL */
  62                         stats->nonprintable++;
  63                 else if (c < 32) {
  64                         switch (c) {
  65                                 /* BS, HT, ESC and FF */
  66                         case '\b': case '\t': case '\033': case '\014':
  67                                 stats->printable++;
  68                                 break;
  69                         case 0:
  70                                 stats->nul++;
  71                                 /* fall through */
  72                         default:
  73                                 stats->nonprintable++;
  74                         }
  75                 }
  76                 else
  77                         stats->printable++;
  78         }
  79
  80         /* If file ends with EOF then don't count this EOF as non-printable. */
  81         if (size >= 1 && buf[size-1] == '\032')
  82                 stats->nonprintable--;
  83 }
  84
  85 /*
  86  * The same heuristics as diff.c::mmfile_is_binary()
  87  * We treat files with bare CR as binary
  88  */
  89 static int convert_is_binary(unsigned long size, const struct text_stat *stats)
  90 {
  91         if (stats->lonecr)
  92                 return 1;
  93         if (stats->nul)
  94                 return 1;
  95         if ((stats->printable >> 7) < stats->nonprintable)
  96                 return 1;
  97         return 0;
  98 }
  99
 100 static unsigned int gather_convert_stats(const char *data, unsigned long size)
 101 {
 102         struct text_stat stats;
 103         int ret = 0;
 104         if (!data || !size)
 105                 return 0;
 106         gather_stats(data, size, &stats);
 107         if (convert_is_binary(size, &stats))
 108                 ret |= CONVERT_STAT_BITS_BIN;
 109         if (stats.crlf)
 110                 ret |= CONVERT_STAT_BITS_TXT_CRLF;
 111         if (stats.lonelf)
 112                 ret |=  CONVERT_STAT_BITS_TXT_LF;
 113
 114         return ret;
 115 }
 116
 117 static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
 118 {
 119         unsigned int convert_stats = gather_convert_stats(data, size);
 120
 121         if (convert_stats & CONVERT_STAT_BITS_BIN)
 122                 return "-text";
 123         switch (convert_stats) {
 124         case CONVERT_STAT_BITS_TXT_LF:
 125                 return "lf";
 126         case CONVERT_STAT_BITS_TXT_CRLF:
 127                 return "crlf";
 128         case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
 129                 return "mixed";
 130         default:
 131                 return "none";
 132         }
 133 }
 134
 135 const char *get_cached_convert_stats_ascii(const char *path)
 136 {
 137         const char *ret;
 138         unsigned long sz;
 139         void *data = read_blob_data_from_cache(path, &sz);
 140         ret = gather_convert_stats_ascii(data, sz);
 141         free(data);
 142         return ret;
 143 }
 144
 145 const char *get_wt_convert_stats_ascii(const char *path)
 146 {
 147         const char *ret = "";
 148         struct strbuf sb = STRBUF_INIT;
 149         if (strbuf_read_file(&sb, path, 0) >= 0)
 150                 ret = gather_convert_stats_ascii(sb.buf, sb.len);
 151         strbuf_release(&sb);
 152         return ret;
 153 }
 154
 155 static int text_eol_is_crlf(void)
 156 {
 157         if (auto_crlf == AUTO_CRLF_TRUE)
 158                 return 1;
 159         else if (auto_crlf == AUTO_CRLF_INPUT)
 160                 return 0;
 161         if (core_eol == EOL_CRLF)
 162                 return 1;
 163         if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
 164                 return 1;
 165         return 0;
 166 }
 167
 168 static enum eol output_eol(enum crlf_action crlf_action)
 169 {
 170         switch (crlf_action) {
 171         case CRLF_BINARY:
 172                 return EOL_UNSET;
 173         case CRLF_TEXT_CRLF:
 174                 return EOL_CRLF;
 175         case CRLF_TEXT_INPUT:
 176                 return EOL_LF;
 177         case CRLF_UNDEFINED:
 178         case CRLF_AUTO_CRLF:
 179                 return EOL_CRLF;
 180         case CRLF_AUTO_INPUT:
 181                 return EOL_LF;
 182         case CRLF_TEXT:
 183         case CRLF_AUTO:
 184                 /* fall through */
 185                 return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
 186         }
 187         warning("Illegal crlf_action %d\n", (int)crlf_action);
 188         return core_eol;
 189 }
 190
 191 static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
 192                             struct text_stat *old_stats, struct text_stat *new_stats,
 193                             enum safe_crlf checksafe)
 194 {
 195         if (old_stats->crlf && !new_stats->crlf ) {
 196                 /*
 197                  * CRLFs would not be restored by checkout
 198                  */
 199                 if (checksafe == SAFE_CRLF_WARN)
 200                         warning("CRLF will be replaced by LF in %s.\nThe file will have its original line endings in your working directory.", path);
 201                 else /* i.e. SAFE_CRLF_FAIL */
 202                         die("CRLF would be replaced by LF in %s.", path);
 203         } else if (old_stats->lonelf && !new_stats->lonelf ) {
 204                 /*
 205                  * CRLFs would be added by checkout
 206                  */
 207                 if (checksafe == SAFE_CRLF_WARN)
 208                         warning("LF will be replaced by CRLF in %s.\nThe file will have its original line endings in your working directory.", path);
 209                 else /* i.e. SAFE_CRLF_FAIL */
 210                         die("LF would be replaced by CRLF in %s", path);
 211         }
 212 }
 213
 214 static int has_cr_in_index(const char *path)
 215 {
 216         unsigned long sz;
 217         void *data;
 218         int has_cr;
 219
 220         data = read_blob_data_from_cache(path, &sz);
 221         if (!data)
 222                 return 0;
 223         has_cr = memchr(data, '\r', sz) != NULL;
 224         free(data);
 225         return has_cr;
 226 }
 227
 228 static int will_convert_lf_to_crlf(size_t len, struct text_stat *stats,
 229                                    enum crlf_action crlf_action)
 230 {
 231         if (output_eol(crlf_action) != EOL_CRLF)
 232                 return 0;
 233         /* No "naked" LF? Nothing to convert, regardless. */
 234         if (!stats->lonelf)
 235                 return 0;
 236
 237         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 238                 /* If we have any CR or CRLF line endings, we do not touch it */
 239                 /* This is the new safer autocrlf-handling */
 240                 if (stats->lonecr || stats->crlf)
 241                         return 0;
 242
 243                 if (convert_is_binary(len, stats))
 244                         return 0;
 245         }
 246         return 1;
 247
 248 }
 249
 250 static int crlf_to_git(const char *path, const char *src, size_t len,
 251                        struct strbuf *buf,
 252                        enum crlf_action crlf_action, enum safe_crlf checksafe)
 253 {
 254         struct text_stat stats;
 255         char *dst;
 256         int convert_crlf_into_lf;
 257
 258         if (crlf_action == CRLF_BINARY ||
 259             (src && !len))
 260                 return 0;
 261
 262         /*
 263          * If we are doing a dry-run and have no source buffer, there is
 264          * nothing to analyze; we must assume we would convert.
 265          */
 266         if (!buf && !src)
 267                 return 1;
 268
 269         gather_stats(src, len, &stats);
 270         /* Optimization: No CRLF? Nothing to convert, regardless. */
 271         convert_crlf_into_lf = !!stats.crlf;
 272
 273         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 274                 if (convert_is_binary(len, &stats))
 275                         return 0;
 276                 /*
 277                  * If the file in the index has any CR in it, do not convert.
 278                  * This is the new safer autocrlf handling.
 279                  */
 280                 if (checksafe == SAFE_CRLF_RENORMALIZE)
 281                         checksafe = SAFE_CRLF_FALSE;
 282                 else if (has_cr_in_index(path))
 283                         convert_crlf_into_lf = 0;
 284         }
 285         if (checksafe && len) {
 286                 struct text_stat new_stats;
 287                 memcpy(&new_stats, &stats, sizeof(new_stats));
 288                 /* simulate "git add" */
 289                 if (convert_crlf_into_lf) {
 290                         new_stats.lonelf += new_stats.crlf;
 291                         new_stats.crlf = 0;
 292                 }
 293                 /* simulate "git checkout" */
 294                 if (will_convert_lf_to_crlf(len, &new_stats, crlf_action)) {
 295                         new_stats.crlf += new_stats.lonelf;
 296                         new_stats.lonelf = 0;
 297                 }
 298                 check_safe_crlf(path, crlf_action, &stats, &new_stats, checksafe);
 299         }
 300         if (!convert_crlf_into_lf)
 301                 return 0;
 302
 303         /*
 304          * At this point all of our source analysis is done, and we are sure we
 305          * would convert. If we are in dry-run mode, we can give an answer.
 306          */
 307         if (!buf)
 308                 return 1;
 309
 310         /* only grow if not in place */
 311         if (strbuf_avail(buf) + buf->len < len)
 312                 strbuf_grow(buf, len - buf->len);
 313         dst = buf->buf;
 314         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 315                 /*
 316                  * If we guessed, we already know we rejected a file with
 317                  * lone CR, and we can strip a CR without looking at what
 318                  * follow it.
 319                  */
 320                 do {
 321                         unsigned char c = *src++;
 322                         if (c != '\r')
 323                                 *dst++ = c;
 324                 } while (--len);
 325         } else {
 326                 do {
 327                         unsigned char c = *src++;
 328                         if (! (c == '\r' && (1 < len && *src == '\n')))
 329                                 *dst++ = c;
 330                 } while (--len);
 331         }
 332         strbuf_setlen(buf, dst - buf->buf);
 333         return 1;
 334 }
 335
 336 static int crlf_to_worktree(const char *path, const char *src, size_t len,
 337                             struct strbuf *buf, enum crlf_action crlf_action)
 338 {
 339         char *to_free = NULL;
 340         struct text_stat stats;
 341
 342         if (!len || output_eol(crlf_action) != EOL_CRLF)
 343                 return 0;
 344
 345         gather_stats(src, len, &stats);
 346         if (!will_convert_lf_to_crlf(len, &stats, crlf_action))
 347                 return 0;
 348
 349         /* are we "faking" in place editing ? */
 350         if (src == buf->buf)
 351                 to_free = strbuf_detach(buf, NULL);
 352
 353         strbuf_grow(buf, len + stats.lonelf);
 354         for (;;) {
 355                 const char *nl = memchr(src, '\n', len);
 356                 if (!nl)
 357                         break;
 358                 if (nl > src && nl[-1] == '\r') {
 359                         strbuf_add(buf, src, nl + 1 - src);
 360                 } else {
 361                         strbuf_add(buf, src, nl - src);
 362                         strbuf_addstr(buf, "\r\n");
 363                 }
 364                 len -= nl + 1 - src;
 365                 src  = nl + 1;
 366         }
 367         strbuf_add(buf, src, len);
 368
 369         free(to_free);
 370         return 1;
 371 }
 372
 373 struct filter_params {
 374         const char *src;
 375         unsigned long size;
 376         int fd;
 377         const char *cmd;
 378         const char *path;
 379 };
 380
 381 static int filter_buffer_or_fd(int in, int out, void *data)
 382 {
 383         /*
 384          * Spawn cmd and feed the buffer contents through its stdin.
 385          */
 386         struct child_process child_process = CHILD_PROCESS_INIT;
 387         struct filter_params *params = (struct filter_params *)data;
 388         int write_err, status;
 389         const char *argv[] = { NULL, NULL };
 390
 391         /* apply % substitution to cmd */
 392         struct strbuf cmd = STRBUF_INIT;
 393         struct strbuf path = STRBUF_INIT;
 394         struct strbuf_expand_dict_entry dict[] = {
 395                 { "f", NULL, },
 396                 { NULL, NULL, },
 397         };
 398
 399         /* quote the path to preserve spaces, etc. */
 400         sq_quote_buf(&path, params->path);
 401         dict[0].value = path.buf;
 402
 403         /* expand all %f with the quoted path */
 404         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 405         strbuf_release(&path);
 406
 407         argv[0] = cmd.buf;
 408
 409         child_process.argv = argv;
 410         child_process.use_shell = 1;
 411         child_process.in = -1;
 412         child_process.out = out;
 413
 414         if (start_command(&child_process))
 415                 return error("cannot fork to run external filter %s", params->cmd);
 416
 417         sigchain_push(SIGPIPE, SIG_IGN);
 418
 419         if (params->src) {
 420                 write_err = (write_in_full(child_process.in,
 421                                            params->src, params->size) < 0);
 422                 if (errno == EPIPE)
 423                         write_err = 0;
 424         } else {
 425                 write_err = copy_fd(params->fd, child_process.in);
 426                 if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
 427                         write_err = 0;
 428         }
 429
 430         if (close(child_process.in))
 431                 write_err = 1;
 432         if (write_err)
 433                 error("cannot feed the input to external filter %s", params->cmd);
 434
 435         sigchain_pop(SIGPIPE);
 436
 437         status = finish_command(&child_process);
 438         if (status)
 439                 error("external filter %s failed %d", params->cmd, status);
 440
 441         strbuf_release(&cmd);
 442         return (write_err || status);
 443 }
 444
 445 static int apply_filter(const char *path, const char *src, size_t len, int fd,
 446                         struct strbuf *dst, const char *cmd)
 447 {
 448         /*
 449          * Create a pipeline to have the command filter the buffer's
 450          * contents.
 451          *
 452          * (child --> cmd) --> us
 453          */
 454         int ret = 1;
 455         struct strbuf nbuf = STRBUF_INIT;
 456         struct async async;
 457         struct filter_params params;
 458
 459         if (!cmd || !*cmd)
 460                 return 0;
 461
 462         if (!dst)
 463                 return 1;
 464
 465         memset(&async, 0, sizeof(async));
 466         async.proc = filter_buffer_or_fd;
 467         async.data = &params;
 468         async.out = -1;
 469         params.src = src;
 470         params.size = len;
 471         params.fd = fd;
 472         params.cmd = cmd;
 473         params.path = path;
 474
 475         fflush(NULL);
 476         if (start_async(&async))
 477                 return 0;       /* error was already reported */
 478
 479         if (strbuf_read(&nbuf, async.out, len) < 0) {
 480                 error("read from external filter %s failed", cmd);
 481                 ret = 0;
 482         }
 483         if (close(async.out)) {
 484                 error("read from external filter %s failed", cmd);
 485                 ret = 0;
 486         }
 487         if (finish_async(&async)) {
 488                 error("external filter %s failed", cmd);
 489                 ret = 0;
 490         }
 491
 492         if (ret) {
 493                 strbuf_swap(dst, &nbuf);
 494         }
 495         strbuf_release(&nbuf);
 496         return ret;
 497 }
 498
 499 static struct convert_driver {
 500         const char *name;
 501         struct convert_driver *next;
 502         const char *smudge;
 503         const char *clean;
 504         int required;
 505 } *user_convert, **user_convert_tail;
 506
 507 static int read_convert_config(const char *var, const char *value, void *cb)
 508 {
 509         const char *key, *name;
 510         int namelen;
 511         struct convert_driver *drv;
 512
 513         /*
 514          * External conversion drivers are configured using
 515          * "filter.<name>.variable".
 516          */
 517         if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 518                 return 0;
 519         for (drv = user_convert; drv; drv = drv->next)
 520                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 521                         break;
 522         if (!drv) {
 523                 drv = xcalloc(1, sizeof(struct convert_driver));
 524                 drv->name = xmemdupz(name, namelen);
 525                 *user_convert_tail = drv;
 526                 user_convert_tail = &(drv->next);
 527         }
 528
 529         /*
 530          * filter.<name>.smudge and filter.<name>.clean specifies
 531          * the command line:
 532          *
 533          *      command-line
 534          *
 535          * The command-line will not be interpolated in any way.
 536          */
 537
 538         if (!strcmp("smudge", key))
 539                 return git_config_string(&drv->smudge, var, value);
 540
 541         if (!strcmp("clean", key))
 542                 return git_config_string(&drv->clean, var, value);
 543
 544         if (!strcmp("required", key)) {
 545                 drv->required = git_config_bool(var, value);
 546                 return 0;
 547         }
 548
 549         return 0;
 550 }
 551
 552 static int count_ident(const char *cp, unsigned long size)
 553 {
 554         /*
 555          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 556          */
 557         int cnt = 0;
 558         char ch;
 559
 560         while (size) {
 561                 ch = *cp++;
 562                 size--;
 563                 if (ch != '$')
 564                         continue;
 565                 if (size < 3)
 566                         break;
 567                 if (memcmp("Id", cp, 2))
 568                         continue;
 569                 ch = cp[2];
 570                 cp += 3;
 571                 size -= 3;
 572                 if (ch == '$')
 573                         cnt++; /* $Id$ */
 574                 if (ch != ':')
 575                         continue;
 576
 577                 /*
 578                  * "$Id: ... "; scan up to the closing dollar sign and discard.
 579                  */
 580                 while (size) {
 581                         ch = *cp++;
 582                         size--;
 583                         if (ch == '$') {
 584                                 cnt++;
 585                                 break;
 586                         }
 587                         if (ch == '\n')
 588                                 break;
 589                 }
 590         }
 591         return cnt;
 592 }
 593
 594 static int ident_to_git(const char *path, const char *src, size_t len,
 595                         struct strbuf *buf, int ident)
 596 {
 597         char *dst, *dollar;
 598
 599         if (!ident || (src && !count_ident(src, len)))
 600                 return 0;
 601
 602         if (!buf)
 603                 return 1;
 604
 605         /* only grow if not in place */
 606         if (strbuf_avail(buf) + buf->len < len)
 607                 strbuf_grow(buf, len - buf->len);
 608         dst = buf->buf;
 609         for (;;) {
 610                 dollar = memchr(src, '$', len);
 611                 if (!dollar)
 612                         break;
 613                 memmove(dst, src, dollar + 1 - src);
 614                 dst += dollar + 1 - src;
 615                 len -= dollar + 1 - src;
 616                 src  = dollar + 1;
 617
 618                 if (len > 3 && !memcmp(src, "Id:", 3)) {
 619                         dollar = memchr(src + 3, '$', len - 3);
 620                         if (!dollar)
 621                                 break;
 622                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 623                                 /* Line break before the next dollar. */
 624                                 continue;
 625                         }
 626
 627                         memcpy(dst, "Id$", 3);
 628                         dst += 3;
 629                         len -= dollar + 1 - src;
 630                         src  = dollar + 1;
 631                 }
 632         }
 633         memmove(dst, src, len);
 634         strbuf_setlen(buf, dst + len - buf->buf);
 635         return 1;
 636 }
 637
 638 static int ident_to_worktree(const char *path, const char *src, size_t len,
 639                              struct strbuf *buf, int ident)
 640 {
 641         unsigned char sha1[20];
 642         char *to_free = NULL, *dollar, *spc;
 643         int cnt;
 644
 645         if (!ident)
 646                 return 0;
 647
 648         cnt = count_ident(src, len);
 649         if (!cnt)
 650                 return 0;
 651
 652         /* are we "faking" in place editing ? */
 653         if (src == buf->buf)
 654                 to_free = strbuf_detach(buf, NULL);
 655         hash_sha1_file(src, len, "blob", sha1);
 656
 657         strbuf_grow(buf, len + cnt * 43);
 658         for (;;) {
 659                 /* step 1: run to the next '$' */
 660                 dollar = memchr(src, '$', len);
 661                 if (!dollar)
 662                         break;
 663                 strbuf_add(buf, src, dollar + 1 - src);
 664                 len -= dollar + 1 - src;
 665                 src  = dollar + 1;
 666
 667                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 668                 if (len < 3 || memcmp("Id", src, 2))
 669                         continue;
 670
 671                 /* step 3: skip over Id$ or Id:xxxxx$ */
 672                 if (src[2] == '$') {
 673                         src += 3;
 674                         len -= 3;
 675                 } else if (src[2] == ':') {
 676                         /*
 677                          * It's possible that an expanded Id has crept its way into the
 678                          * repository, we cope with that by stripping the expansion out.
 679                          * This is probably not a good idea, since it will cause changes
 680                          * on checkout, which won't go away by stash, but let's keep it
 681                          * for git-style ids.
 682                          */
 683                         dollar = memchr(src + 3, '$', len - 3);
 684                         if (!dollar) {
 685                                 /* incomplete keyword, no more '$', so just quit the loop */
 686                                 break;
 687                         }
 688
 689                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 690                                 /* Line break before the next dollar. */
 691                                 continue;
 692                         }
 693
 694                         spc = memchr(src + 4, ' ', dollar - src - 4);
 695                         if (spc && spc < dollar-1) {
 696                                 /* There are spaces in unexpected places.
 697                                  * This is probably an id from some other
 698                                  * versioning system. Keep it for now.
 699                                  */
 700                                 continue;
 701                         }
 702
 703                         len -= dollar + 1 - src;
 704                         src  = dollar + 1;
 705                 } else {
 706                         /* it wasn't a "Id$" or "Id:xxxx$" */
 707                         continue;
 708                 }
 709
 710                 /* step 4: substitute */
 711                 strbuf_addstr(buf, "Id: ");
 712                 strbuf_add(buf, sha1_to_hex(sha1), 40);
 713                 strbuf_addstr(buf, " $");
 714         }
 715         strbuf_add(buf, src, len);
 716
 717         free(to_free);
 718         return 1;
 719 }
 720
 721 static enum crlf_action git_path_check_crlf(struct git_attr_check *check)
 722 {
 723         const char *value = check->value;
 724
 725         if (ATTR_TRUE(value))
 726                 return CRLF_TEXT;
 727         else if (ATTR_FALSE(value))
 728                 return CRLF_BINARY;
 729         else if (ATTR_UNSET(value))
 730                 ;
 731         else if (!strcmp(value, "input"))
 732                 return CRLF_TEXT_INPUT;
 733         else if (!strcmp(value, "auto"))
 734                 return CRLF_AUTO;
 735         return CRLF_UNDEFINED;
 736 }
 737
 738 static enum eol git_path_check_eol(struct git_attr_check *check)
 739 {
 740         const char *value = check->value;
 741
 742         if (ATTR_UNSET(value))
 743                 ;
 744         else if (!strcmp(value, "lf"))
 745                 return EOL_LF;
 746         else if (!strcmp(value, "crlf"))
 747                 return EOL_CRLF;
 748         return EOL_UNSET;
 749 }
 750
 751 static struct convert_driver *git_path_check_convert(struct git_attr_check *check)
 752 {
 753         const char *value = check->value;
 754         struct convert_driver *drv;
 755
 756         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 757                 return NULL;
 758         for (drv = user_convert; drv; drv = drv->next)
 759                 if (!strcmp(value, drv->name))
 760                         return drv;
 761         return NULL;
 762 }
 763
 764 static int git_path_check_ident(struct git_attr_check *check)
 765 {
 766         const char *value = check->value;
 767
 768         return !!ATTR_TRUE(value);
 769 }
 770
 771 struct conv_attrs {
 772         struct convert_driver *drv;
 773         enum crlf_action attr_action; /* What attr says */
 774         enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
 775         int ident;
 776 };
 777
 778 static const char *conv_attr_name[] = {
 779         "crlf", "ident", "filter", "eol", "text",
 780 };
 781 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 782
 783 static void convert_attrs(struct conv_attrs *ca, const char *path)
 784 {
 785         int i;
 786         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 787
 788         if (!ccheck[0].attr) {
 789                 for (i = 0; i < NUM_CONV_ATTRS; i++)
 790                         ccheck[i].attr = git_attr(conv_attr_name[i]);
 791                 user_convert_tail = &user_convert;
 792                 git_config(read_convert_config, NULL);
 793         }
 794
 795         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 796                 ca->crlf_action = git_path_check_crlf(ccheck + 4);
 797                 if (ca->crlf_action == CRLF_UNDEFINED)
 798                         ca->crlf_action = git_path_check_crlf(ccheck + 0);
 799                 ca->attr_action = ca->crlf_action;
 800                 ca->ident = git_path_check_ident(ccheck + 1);
 801                 ca->drv = git_path_check_convert(ccheck + 2);
 802                 if (ca->crlf_action != CRLF_BINARY) {
 803                         enum eol eol_attr = git_path_check_eol(ccheck + 3);
 804                         if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
 805                                 ca->crlf_action = CRLF_AUTO_INPUT;
 806                         else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
 807                                 ca->crlf_action = CRLF_AUTO_CRLF;
 808                         else if (eol_attr == EOL_LF)
 809                                 ca->crlf_action = CRLF_TEXT_INPUT;
 810                         else if (eol_attr == EOL_CRLF)
 811                                 ca->crlf_action = CRLF_TEXT_CRLF;
 812                 }
 813                 ca->attr_action = ca->crlf_action;
 814         } else {
 815                 ca->drv = NULL;
 816                 ca->crlf_action = CRLF_UNDEFINED;
 817                 ca->ident = 0;
 818         }
 819         if (ca->crlf_action == CRLF_TEXT)
 820                 ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
 821         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
 822                 ca->crlf_action = CRLF_BINARY;
 823         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
 824                 ca->crlf_action = CRLF_AUTO_CRLF;
 825         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
 826                 ca->crlf_action = CRLF_AUTO_INPUT;
 827 }
 828
 829 int would_convert_to_git_filter_fd(const char *path)
 830 {
 831         struct conv_attrs ca;
 832
 833         convert_attrs(&ca, path);
 834         if (!ca.drv)
 835                 return 0;
 836
 837         /*
 838          * Apply a filter to an fd only if the filter is required to succeed.
 839          * We must die if the filter fails, because the original data before
 840          * filtering is not available.
 841          */
 842         if (!ca.drv->required)
 843                 return 0;
 844
 845         return apply_filter(path, NULL, 0, -1, NULL, ca.drv->clean);
 846 }
 847
 848 const char *get_convert_attr_ascii(const char *path)
 849 {
 850         struct conv_attrs ca;
 851
 852         convert_attrs(&ca, path);
 853         switch (ca.attr_action) {
 854         case CRLF_UNDEFINED:
 855                 return "";
 856         case CRLF_BINARY:
 857                 return "-text";
 858         case CRLF_TEXT:
 859                 return "text";
 860         case CRLF_TEXT_INPUT:
 861                 return "text eol=lf";
 862         case CRLF_TEXT_CRLF:
 863                 return "text eol=crlf";
 864         case CRLF_AUTO:
 865                 return "text=auto";
 866         case CRLF_AUTO_CRLF:
 867                 return "text=auto eol=crlf";
 868         case CRLF_AUTO_INPUT:
 869                 return "text=auto eol=lf";
 870         }
 871         return "";
 872 }
 873
 874 int convert_to_git(const char *path, const char *src, size_t len,
 875                    struct strbuf *dst, enum safe_crlf checksafe)
 876 {
 877         int ret = 0;
 878         const char *filter = NULL;
 879         int required = 0;
 880         struct conv_attrs ca;
 881
 882         convert_attrs(&ca, path);
 883         if (ca.drv) {
 884                 filter = ca.drv->clean;
 885                 required = ca.drv->required;
 886         }
 887
 888         ret |= apply_filter(path, src, len, -1, dst, filter);
 889         if (!ret && required)
 890                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 891
 892         if (ret && dst) {
 893                 src = dst->buf;
 894                 len = dst->len;
 895         }
 896         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 897         if (ret && dst) {
 898                 src = dst->buf;
 899                 len = dst->len;
 900         }
 901         return ret | ident_to_git(path, src, len, dst, ca.ident);
 902 }
 903
 904 void convert_to_git_filter_fd(const char *path, int fd, struct strbuf *dst,
 905                               enum safe_crlf checksafe)
 906 {
 907         struct conv_attrs ca;
 908         convert_attrs(&ca, path);
 909
 910         assert(ca.drv);
 911         assert(ca.drv->clean);
 912
 913         if (!apply_filter(path, NULL, 0, fd, dst, ca.drv->clean))
 914                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 915
 916         crlf_to_git(path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
 917         ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
 918 }
 919
 920 static int convert_to_working_tree_internal(const char *path, const char *src,
 921                                             size_t len, struct strbuf *dst,
 922                                             int normalizing)
 923 {
 924         int ret = 0, ret_filter = 0;
 925         const char *filter = NULL;
 926         int required = 0;
 927         struct conv_attrs ca;
 928
 929         convert_attrs(&ca, path);
 930         if (ca.drv) {
 931                 filter = ca.drv->smudge;
 932                 required = ca.drv->required;
 933         }
 934
 935         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 936         if (ret) {
 937                 src = dst->buf;
 938                 len = dst->len;
 939         }
 940         /*
 941          * CRLF conversion can be skipped if normalizing, unless there
 942          * is a smudge filter.  The filter might expect CRLFs.
 943          */
 944         if (filter || !normalizing) {
 945                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 946                 if (ret) {
 947                         src = dst->buf;
 948                         len = dst->len;
 949                 }
 950         }
 951
 952         ret_filter = apply_filter(path, src, len, -1, dst, filter);
 953         if (!ret_filter && required)
 954                 die("%s: smudge filter %s failed", path, ca.drv->name);
 955
 956         return ret | ret_filter;
 957 }
 958
 959 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 960 {
 961         return convert_to_working_tree_internal(path, src, len, dst, 0);
 962 }
 963
 964 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 965 {
 966         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 967         if (ret) {
 968                 src = dst->buf;
 969                 len = dst->len;
 970         }
 971         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_RENORMALIZE);
 972 }
 973
 974 /*****************************************************************
 975  *
 976  * Streaming conversion support
 977  *
 978  *****************************************************************/
 979
 980 typedef int (*filter_fn)(struct stream_filter *,
 981                          const char *input, size_t *isize_p,
 982                          char *output, size_t *osize_p);
 983 typedef void (*free_fn)(struct stream_filter *);
 984
 985 struct stream_filter_vtbl {
 986         filter_fn filter;
 987         free_fn free;
 988 };
 989
 990 struct stream_filter {
 991         struct stream_filter_vtbl *vtbl;
 992 };
 993
 994 static int null_filter_fn(struct stream_filter *filter,
 995                           const char *input, size_t *isize_p,
 996                           char *output, size_t *osize_p)
 997 {
 998         size_t count;
 999
1000         if (!input)
1001                 return 0; /* we do not keep any states */
1002         count = *isize_p;
1003         if (*osize_p < count)
1004                 count = *osize_p;
1005         if (count) {
1006                 memmove(output, input, count);
1007                 *isize_p -= count;
1008                 *osize_p -= count;
1009         }
1010         return 0;
1011 }
1012
1013 static void null_free_fn(struct stream_filter *filter)
1014 {
1015         ; /* nothing -- null instances are shared */
1016 }
1017
1018 static struct stream_filter_vtbl null_vtbl = {
1019         null_filter_fn,
1020         null_free_fn,
1021 };
1022
1023 static struct stream_filter null_filter_singleton = {
1024         &null_vtbl,
1025 };
1026
1027 int is_null_stream_filter(struct stream_filter *filter)
1028 {
1029         return filter == &null_filter_singleton;
1030 }
1031
1032
1033 /*
1034  * LF-to-CRLF filter
1035  */
1036
1037 struct lf_to_crlf_filter {
1038         struct stream_filter filter;
1039         unsigned has_held:1;
1040         char held;
1041 };
1042
1043 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1044                                 const char *input, size_t *isize_p,
1045                                 char *output, size_t *osize_p)
1046 {
1047         size_t count, o = 0;
1048         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1049
1050         /*
1051          * We may be holding onto the CR to see if it is followed by a
1052          * LF, in which case we would need to go to the main loop.
1053          * Otherwise, just emit it to the output stream.
1054          */
1055         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1056                 output[o++] = lf_to_crlf->held;
1057                 lf_to_crlf->has_held = 0;
1058         }
1059
1060         /* We are told to drain */
1061         if (!input) {
1062                 *osize_p -= o;
1063                 return 0;
1064         }
1065
1066         count = *isize_p;
1067         if (count || lf_to_crlf->has_held) {
1068                 size_t i;
1069                 int was_cr = 0;
1070
1071                 if (lf_to_crlf->has_held) {
1072                         was_cr = 1;
1073                         lf_to_crlf->has_held = 0;
1074                 }
1075
1076                 for (i = 0; o < *osize_p && i < count; i++) {
1077                         char ch = input[i];
1078
1079                         if (ch == '\n') {
1080                                 output[o++] = '\r';
1081                         } else if (was_cr) {
1082                                 /*
1083                                  * Previous round saw CR and it is not followed
1084                                  * by a LF; emit the CR before processing the
1085                                  * current character.
1086                                  */
1087                                 output[o++] = '\r';
1088                         }
1089
1090                         /*
1091                          * We may have consumed the last output slot,
1092                          * in which case we need to break out of this
1093                          * loop; hold the current character before
1094                          * returning.
1095                          */
1096                         if (*osize_p <= o) {
1097                                 lf_to_crlf->has_held = 1;
1098                                 lf_to_crlf->held = ch;
1099                                 continue; /* break but increment i */
1100                         }
1101
1102                         if (ch == '\r') {
1103                                 was_cr = 1;
1104                                 continue;
1105                         }
1106
1107                         was_cr = 0;
1108                         output[o++] = ch;
1109                 }
1110
1111                 *osize_p -= o;
1112                 *isize_p -= i;
1113
1114                 if (!lf_to_crlf->has_held && was_cr) {
1115                         lf_to_crlf->has_held = 1;
1116                         lf_to_crlf->held = '\r';
1117                 }
1118         }
1119         return 0;
1120 }
1121
1122 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1123 {
1124         free(filter);
1125 }
1126
1127 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1128         lf_to_crlf_filter_fn,
1129         lf_to_crlf_free_fn,
1130 };
1131
1132 static struct stream_filter *lf_to_crlf_filter(void)
1133 {
1134         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1135
1136         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1137         return (struct stream_filter *)lf_to_crlf;
1138 }
1139
1140 /*
1141  * Cascade filter
1142  */
1143 #define FILTER_BUFFER 1024
1144 struct cascade_filter {
1145         struct stream_filter filter;
1146         struct stream_filter *one;
1147         struct stream_filter *two;
1148         char buf[FILTER_BUFFER];
1149         int end, ptr;
1150 };
1151
1152 static int cascade_filter_fn(struct stream_filter *filter,
1153                              const char *input, size_t *isize_p,
1154                              char *output, size_t *osize_p)
1155 {
1156         struct cascade_filter *cas = (struct cascade_filter *) filter;
1157         size_t filled = 0;
1158         size_t sz = *osize_p;
1159         size_t to_feed, remaining;
1160
1161         /*
1162          * input -- (one) --> buf -- (two) --> output
1163          */
1164         while (filled < sz) {
1165                 remaining = sz - filled;
1166
1167                 /* do we already have something to feed two with? */
1168                 if (cas->ptr < cas->end) {
1169                         to_feed = cas->end - cas->ptr;
1170                         if (stream_filter(cas->two,
1171                                           cas->buf + cas->ptr, &to_feed,
1172                                           output + filled, &remaining))
1173                                 return -1;
1174                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1175                         filled = sz - remaining;
1176                         continue;
1177                 }
1178
1179                 /* feed one from upstream and have it emit into our buffer */
1180                 to_feed = input ? *isize_p : 0;
1181                 if (input && !to_feed)
1182                         break;
1183                 remaining = sizeof(cas->buf);
1184                 if (stream_filter(cas->one,
1185                                   input, &to_feed,
1186                                   cas->buf, &remaining))
1187                         return -1;
1188                 cas->end = sizeof(cas->buf) - remaining;
1189                 cas->ptr = 0;
1190                 if (input) {
1191                         size_t fed = *isize_p - to_feed;
1192                         *isize_p -= fed;
1193                         input += fed;
1194                 }
1195
1196                 /* do we know that we drained one completely? */
1197                 if (input || cas->end)
1198                         continue;
1199
1200                 /* tell two to drain; we have nothing more to give it */
1201                 to_feed = 0;
1202                 remaining = sz - filled;
1203                 if (stream_filter(cas->two,
1204                                   NULL, &to_feed,
1205                                   output + filled, &remaining))
1206                         return -1;
1207                 if (remaining == (sz - filled))
1208                         break; /* completely drained two */
1209                 filled = sz - remaining;
1210         }
1211         *osize_p -= filled;
1212         return 0;
1213 }
1214
1215 static void cascade_free_fn(struct stream_filter *filter)
1216 {
1217         struct cascade_filter *cas = (struct cascade_filter *)filter;
1218         free_stream_filter(cas->one);
1219         free_stream_filter(cas->two);
1220         free(filter);
1221 }
1222
1223 static struct stream_filter_vtbl cascade_vtbl = {
1224         cascade_filter_fn,
1225         cascade_free_fn,
1226 };
1227
1228 static struct stream_filter *cascade_filter(struct stream_filter *one,
1229                                             struct stream_filter *two)
1230 {
1231         struct cascade_filter *cascade;
1232
1233         if (!one || is_null_stream_filter(one))
1234                 return two;
1235         if (!two || is_null_stream_filter(two))
1236                 return one;
1237
1238         cascade = xmalloc(sizeof(*cascade));
1239         cascade->one = one;
1240         cascade->two = two;
1241         cascade->end = cascade->ptr = 0;
1242         cascade->filter.vtbl = &cascade_vtbl;
1243         return (struct stream_filter *)cascade;
1244 }
1245
1246 /*
1247  * ident filter
1248  */
1249 #define IDENT_DRAINING (-1)
1250 #define IDENT_SKIPPING (-2)
1251 struct ident_filter {
1252         struct stream_filter filter;
1253         struct strbuf left;
1254         int state;
1255         char ident[45]; /* ": x40 $" */
1256 };
1257
1258 static int is_foreign_ident(const char *str)
1259 {
1260         int i;
1261
1262         if (!skip_prefix(str, "$Id: ", &str))
1263                 return 0;
1264         for (i = 0; str[i]; i++) {
1265                 if (isspace(str[i]) && str[i+1] != '$')
1266                         return 1;
1267         }
1268         return 0;
1269 }
1270
1271 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1272 {
1273         size_t to_drain = ident->left.len;
1274
1275         if (*osize_p < to_drain)
1276                 to_drain = *osize_p;
1277         if (to_drain) {
1278                 memcpy(*output_p, ident->left.buf, to_drain);
1279                 strbuf_remove(&ident->left, 0, to_drain);
1280                 *output_p += to_drain;
1281                 *osize_p -= to_drain;
1282         }
1283         if (!ident->left.len)
1284                 ident->state = 0;
1285 }
1286
1287 static int ident_filter_fn(struct stream_filter *filter,
1288                            const char *input, size_t *isize_p,
1289                            char *output, size_t *osize_p)
1290 {
1291         struct ident_filter *ident = (struct ident_filter *)filter;
1292         static const char head[] = "$Id";
1293
1294         if (!input) {
1295                 /* drain upon eof */
1296                 switch (ident->state) {
1297                 default:
1298                         strbuf_add(&ident->left, head, ident->state);
1299                 case IDENT_SKIPPING:
1300                         /* fallthru */
1301                 case IDENT_DRAINING:
1302                         ident_drain(ident, &output, osize_p);
1303                 }
1304                 return 0;
1305         }
1306
1307         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1308                 int ch;
1309
1310                 if (ident->state == IDENT_DRAINING) {
1311                         ident_drain(ident, &output, osize_p);
1312                         if (!*osize_p)
1313                                 break;
1314                         continue;
1315                 }
1316
1317                 ch = *(input++);
1318                 (*isize_p)--;
1319
1320                 if (ident->state == IDENT_SKIPPING) {
1321                         /*
1322                          * Skipping until '$' or LF, but keeping them
1323                          * in case it is a foreign ident.
1324                          */
1325                         strbuf_addch(&ident->left, ch);
1326                         if (ch != '\n' && ch != '$')
1327                                 continue;
1328                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1329                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1330                                 strbuf_addstr(&ident->left, ident->ident);
1331                         }
1332                         ident->state = IDENT_DRAINING;
1333                         continue;
1334                 }
1335
1336                 if (ident->state < sizeof(head) &&
1337                     head[ident->state] == ch) {
1338                         ident->state++;
1339                         continue;
1340                 }
1341
1342                 if (ident->state)
1343                         strbuf_add(&ident->left, head, ident->state);
1344                 if (ident->state == sizeof(head) - 1) {
1345                         if (ch != ':' && ch != '$') {
1346                                 strbuf_addch(&ident->left, ch);
1347                                 ident->state = 0;
1348                                 continue;
1349                         }
1350
1351                         if (ch == ':') {
1352                                 strbuf_addch(&ident->left, ch);
1353                                 ident->state = IDENT_SKIPPING;
1354                         } else {
1355                                 strbuf_addstr(&ident->left, ident->ident);
1356                                 ident->state = IDENT_DRAINING;
1357                         }
1358                         continue;
1359                 }
1360
1361                 strbuf_addch(&ident->left, ch);
1362                 ident->state = IDENT_DRAINING;
1363         }
1364         return 0;
1365 }
1366
1367 static void ident_free_fn(struct stream_filter *filter)
1368 {
1369         struct ident_filter *ident = (struct ident_filter *)filter;
1370         strbuf_release(&ident->left);
1371         free(filter);
1372 }
1373
1374 static struct stream_filter_vtbl ident_vtbl = {
1375         ident_filter_fn,
1376         ident_free_fn,
1377 };
1378
1379 static struct stream_filter *ident_filter(const unsigned char *sha1)
1380 {
1381         struct ident_filter *ident = xmalloc(sizeof(*ident));
1382
1383         xsnprintf(ident->ident, sizeof(ident->ident),
1384                   ": %s $", sha1_to_hex(sha1));
1385         strbuf_init(&ident->left, 0);
1386         ident->filter.vtbl = &ident_vtbl;
1387         ident->state = 0;
1388         return (struct stream_filter *)ident;
1389 }
1390
1391 /*
1392  * Return an appropriately constructed filter for the path, or NULL if
1393  * the contents cannot be filtered without reading the whole thing
1394  * in-core.
1395  *
1396  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1397  * large binary blob you would want us not to slurp into the memory!
1398  */
1399 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1400 {
1401         struct conv_attrs ca;
1402         struct stream_filter *filter = NULL;
1403
1404         convert_attrs(&ca, path);
1405         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1406                 return NULL;
1407
1408         if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1409                 return NULL;
1410
1411         if (ca.ident)
1412                 filter = ident_filter(sha1);
1413
1414         if (output_eol(ca.crlf_action) == EOL_CRLF)
1415                 filter = cascade_filter(filter, lf_to_crlf_filter());
1416         else
1417                 filter = cascade_filter(filter, &null_filter_singleton);
1418
1419         return filter;
1420 }
1421
1422 void free_stream_filter(struct stream_filter *filter)
1423 {
1424         filter->vtbl->free(filter);
1425 }
1426
1427 int stream_filter(struct stream_filter *filter,
1428                   const char *input, size_t *isize_p,
1429                   char *output, size_t *osize_p)
1430 {
1431         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1432 }