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