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