git.oblomov.eu Git - git/blob - convert.c

   1 #include "cache.h"
   2 #include "attr.h"
   3 #include "run-command.h"
   4 #include "quote.h"
   5 #include "sigchain.h"
   6
   7 /*
   8  * convert.c - convert a file when checking it out and checking it in.
   9  *
  10  * This should use the pathname to decide on whether it wants to do some
  11  * more interesting conversions (automatic gzip/unzip, general format
  12  * conversions etc etc), but by default it just does automatic CRLF<->LF
  13  * translation when the "text" attribute or "auto_crlf" option is set.
  14  */
  15
  16 /* Stat bits: When BIN is set, the txt bits are unset */
  17 #define CONVERT_STAT_BITS_TXT_LF    0x1
  18 #define CONVERT_STAT_BITS_TXT_CRLF  0x2
  19 #define CONVERT_STAT_BITS_BIN       0x4
  20
  21 enum crlf_action {
  22         CRLF_UNDEFINED,
  23         CRLF_BINARY,
  24         CRLF_TEXT,
  25         CRLF_TEXT_INPUT,
  26         CRLF_TEXT_CRLF,
  27         CRLF_AUTO,
  28         CRLF_AUTO_INPUT,
  29         CRLF_AUTO_CRLF
  30 };
  31
  32 struct text_stat {
  33         /* NUL, CR, LF and CRLF counts */
  34         unsigned nul, lonecr, lonelf, crlf;
  35
  36         /* These are just approximations! */
  37         unsigned printable, nonprintable;
  38 };
  39
  40 static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  41 {
  42         unsigned long i;
  43
  44         memset(stats, 0, sizeof(*stats));
  45
  46         for (i = 0; i < size; i++) {
  47                 unsigned char c = buf[i];
  48                 if (c == '\r') {
  49                         if (i+1 < size && buf[i+1] == '\n') {
  50                                 stats->crlf++;
  51                                 i++;
  52                         } else
  53                                 stats->lonecr++;
  54                         continue;
  55                 }
  56                 if (c == '\n') {
  57                         stats->lonelf++;
  58                         continue;
  59                 }
  60                 if (c == 127)
  61                         /* DEL */
  62                         stats->nonprintable++;
  63                 else if (c < 32) {
  64                         switch (c) {
  65                                 /* BS, HT, ESC and FF */
  66                         case '\b': case '\t': case '\033': case '\014':
  67                                 stats->printable++;
  68                                 break;
  69                         case 0:
  70                                 stats->nul++;
  71                                 /* fall through */
  72                         default:
  73                                 stats->nonprintable++;
  74                         }
  75                 }
  76                 else
  77                         stats->printable++;
  78         }
  79
  80         /* If file ends with EOF then don't count this EOF as non-printable. */
  81         if (size >= 1 && buf[size-1] == '\032')
  82                 stats->nonprintable--;
  83 }
  84
  85 /*
  86  * The same heuristics as diff.c::mmfile_is_binary()
  87  * We treat files with bare CR as binary
  88  */
  89 static int convert_is_binary(unsigned long size, const struct text_stat *stats)
  90 {
  91         if (stats->lonecr)
  92                 return 1;
  93         if (stats->nul)
  94                 return 1;
  95         if ((stats->printable >> 7) < stats->nonprintable)
  96                 return 1;
  97         return 0;
  98 }
  99
 100 static unsigned int gather_convert_stats(const char *data, unsigned long size)
 101 {
 102         struct text_stat stats;
 103         int ret = 0;
 104         if (!data || !size)
 105                 return 0;
 106         gather_stats(data, size, &stats);
 107         if (convert_is_binary(size, &stats))
 108                 ret |= CONVERT_STAT_BITS_BIN;
 109         if (stats.crlf)
 110                 ret |= CONVERT_STAT_BITS_TXT_CRLF;
 111         if (stats.lonelf)
 112                 ret |=  CONVERT_STAT_BITS_TXT_LF;
 113
 114         return ret;
 115 }
 116
 117 static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
 118 {
 119         unsigned int convert_stats = gather_convert_stats(data, size);
 120
 121         if (convert_stats & CONVERT_STAT_BITS_BIN)
 122                 return "-text";
 123         switch (convert_stats) {
 124         case CONVERT_STAT_BITS_TXT_LF:
 125                 return "lf";
 126         case CONVERT_STAT_BITS_TXT_CRLF:
 127                 return "crlf";
 128         case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
 129                 return "mixed";
 130         default:
 131                 return "none";
 132         }
 133 }
 134
 135 const char *get_cached_convert_stats_ascii(const char *path)
 136 {
 137         const char *ret;
 138         unsigned long sz;
 139         void *data = read_blob_data_from_cache(path, &sz);
 140         ret = gather_convert_stats_ascii(data, sz);
 141         free(data);
 142         return ret;
 143 }
 144
 145 const char *get_wt_convert_stats_ascii(const char *path)
 146 {
 147         const char *ret = "";
 148         struct strbuf sb = STRBUF_INIT;
 149         if (strbuf_read_file(&sb, path, 0) >= 0)
 150                 ret = gather_convert_stats_ascii(sb.buf, sb.len);
 151         strbuf_release(&sb);
 152         return ret;
 153 }
 154
 155 static int text_eol_is_crlf(void)
 156 {
 157         if (auto_crlf == AUTO_CRLF_TRUE)
 158                 return 1;
 159         else if (auto_crlf == AUTO_CRLF_INPUT)
 160                 return 0;
 161         if (core_eol == EOL_CRLF)
 162                 return 1;
 163         if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
 164                 return 1;
 165         return 0;
 166 }
 167
 168 static enum eol output_eol(enum crlf_action crlf_action)
 169 {
 170         switch (crlf_action) {
 171         case CRLF_BINARY:
 172                 return EOL_UNSET;
 173         case CRLF_TEXT_CRLF:
 174                 return EOL_CRLF;
 175         case CRLF_TEXT_INPUT:
 176                 return EOL_LF;
 177         case CRLF_UNDEFINED:
 178         case CRLF_AUTO_CRLF:
 179                 return EOL_CRLF;
 180         case CRLF_AUTO_INPUT:
 181                 return EOL_LF;
 182         case CRLF_TEXT:
 183         case CRLF_AUTO:
 184                 /* fall through */
 185                 return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
 186         }
 187         warning("Illegal crlf_action %d\n", (int)crlf_action);
 188         return core_eol;
 189 }
 190
 191 static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
 192                             struct text_stat *old_stats, struct text_stat *new_stats,
 193                             enum safe_crlf checksafe)
 194 {
 195         if (old_stats->crlf && !new_stats->crlf ) {
 196                 /*
 197                  * CRLFs would not be restored by checkout
 198                  */
 199                 if (checksafe == SAFE_CRLF_WARN)
 200                         warning(_("CRLF will be replaced by LF in %s.\n"
 201                                   "The file will have its original line"
 202                                   " endings in your working directory."), path);
 203                 else /* i.e. SAFE_CRLF_FAIL */
 204                         die(_("CRLF would be replaced by LF in %s."), path);
 205         } else if (old_stats->lonelf && !new_stats->lonelf ) {
 206                 /*
 207                  * CRLFs would be added by checkout
 208                  */
 209                 if (checksafe == SAFE_CRLF_WARN)
 210                         warning(_("LF will be replaced by CRLF in %s.\n"
 211                                   "The file will have its original line"
 212                                   " 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 static int has_cr_in_index(const char *path)
 219 {
 220         unsigned long sz;
 221         void *data;
 222         int has_cr;
 223
 224         data = read_blob_data_from_cache(path, &sz);
 225         if (!data)
 226                 return 0;
 227         has_cr = memchr(data, '\r', sz) != NULL;
 228         free(data);
 229         return has_cr;
 230 }
 231
 232 static int will_convert_lf_to_crlf(size_t len, struct text_stat *stats,
 233                                    enum crlf_action crlf_action)
 234 {
 235         if (output_eol(crlf_action) != EOL_CRLF)
 236                 return 0;
 237         /* No "naked" LF? Nothing to convert, regardless. */
 238         if (!stats->lonelf)
 239                 return 0;
 240
 241         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 242                 /* If we have any CR or CRLF line endings, we do not touch it */
 243                 /* This is the new safer autocrlf-handling */
 244                 if (stats->lonecr || stats->crlf)
 245                         return 0;
 246
 247                 if (convert_is_binary(len, stats))
 248                         return 0;
 249         }
 250         return 1;
 251
 252 }
 253
 254 static int crlf_to_git(const char *path, const char *src, size_t len,
 255                        struct strbuf *buf,
 256                        enum crlf_action crlf_action, enum safe_crlf checksafe)
 257 {
 258         struct text_stat stats;
 259         char *dst;
 260         int convert_crlf_into_lf;
 261
 262         if (crlf_action == CRLF_BINARY ||
 263             (src && !len))
 264                 return 0;
 265
 266         /*
 267          * If we are doing a dry-run and have no source buffer, there is
 268          * nothing to analyze; we must assume we would convert.
 269          */
 270         if (!buf && !src)
 271                 return 1;
 272
 273         gather_stats(src, len, &stats);
 274         /* Optimization: No CRLF? Nothing to convert, regardless. */
 275         convert_crlf_into_lf = !!stats.crlf;
 276
 277         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 278                 if (convert_is_binary(len, &stats))
 279                         return 0;
 280                 /*
 281                  * If the file in the index has any CR in it, do not convert.
 282                  * This is the new safer autocrlf handling.
 283                  */
 284                 if (checksafe == SAFE_CRLF_RENORMALIZE)
 285                         checksafe = SAFE_CRLF_FALSE;
 286                 else if (has_cr_in_index(path))
 287                         convert_crlf_into_lf = 0;
 288         }
 289         if (checksafe && len) {
 290                 struct text_stat new_stats;
 291                 memcpy(&new_stats, &stats, sizeof(new_stats));
 292                 /* simulate "git add" */
 293                 if (convert_crlf_into_lf) {
 294                         new_stats.lonelf += new_stats.crlf;
 295                         new_stats.crlf = 0;
 296                 }
 297                 /* simulate "git checkout" */
 298                 if (will_convert_lf_to_crlf(len, &new_stats, crlf_action)) {
 299                         new_stats.crlf += new_stats.lonelf;
 300                         new_stats.lonelf = 0;
 301                 }
 302                 check_safe_crlf(path, crlf_action, &stats, &new_stats, checksafe);
 303         }
 304         if (!convert_crlf_into_lf)
 305                 return 0;
 306
 307         /*
 308          * At this point all of our source analysis is done, and we are sure we
 309          * would convert. If we are in dry-run mode, we can give an answer.
 310          */
 311         if (!buf)
 312                 return 1;
 313
 314         /* only grow if not in place */
 315         if (strbuf_avail(buf) + buf->len < len)
 316                 strbuf_grow(buf, len - buf->len);
 317         dst = buf->buf;
 318         if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 319                 /*
 320                  * If we guessed, we already know we rejected a file with
 321                  * lone CR, and we can strip a CR without looking at what
 322                  * follow it.
 323                  */
 324                 do {
 325                         unsigned char c = *src++;
 326                         if (c != '\r')
 327                                 *dst++ = c;
 328                 } while (--len);
 329         } else {
 330                 do {
 331                         unsigned char c = *src++;
 332                         if (! (c == '\r' && (1 < len && *src == '\n')))
 333                                 *dst++ = c;
 334                 } while (--len);
 335         }
 336         strbuf_setlen(buf, dst - buf->buf);
 337         return 1;
 338 }
 339
 340 static int crlf_to_worktree(const char *path, const char *src, size_t len,
 341                             struct strbuf *buf, enum crlf_action crlf_action)
 342 {
 343         char *to_free = NULL;
 344         struct text_stat stats;
 345
 346         if (!len || output_eol(crlf_action) != EOL_CRLF)
 347                 return 0;
 348
 349         gather_stats(src, len, &stats);
 350         if (!will_convert_lf_to_crlf(len, &stats, crlf_action))
 351                 return 0;
 352
 353         /* are we "faking" in place editing ? */
 354         if (src == buf->buf)
 355                 to_free = strbuf_detach(buf, NULL);
 356
 357         strbuf_grow(buf, len + stats.lonelf);
 358         for (;;) {
 359                 const char *nl = memchr(src, '\n', len);
 360                 if (!nl)
 361                         break;
 362                 if (nl > src && nl[-1] == '\r') {
 363                         strbuf_add(buf, src, nl + 1 - src);
 364                 } else {
 365                         strbuf_add(buf, src, nl - src);
 366                         strbuf_addstr(buf, "\r\n");
 367                 }
 368                 len -= nl + 1 - src;
 369                 src  = nl + 1;
 370         }
 371         strbuf_add(buf, src, len);
 372
 373         free(to_free);
 374         return 1;
 375 }
 376
 377 struct filter_params {
 378         const char *src;
 379         unsigned long size;
 380         int fd;
 381         const char *cmd;
 382         const char *path;
 383 };
 384
 385 static int filter_buffer_or_fd(int in, int out, void *data)
 386 {
 387         /*
 388          * Spawn cmd and feed the buffer contents through its stdin.
 389          */
 390         struct child_process child_process = CHILD_PROCESS_INIT;
 391         struct filter_params *params = (struct filter_params *)data;
 392         int write_err, status;
 393         const char *argv[] = { NULL, NULL };
 394
 395         /* apply % substitution to cmd */
 396         struct strbuf cmd = STRBUF_INIT;
 397         struct strbuf path = STRBUF_INIT;
 398         struct strbuf_expand_dict_entry dict[] = {
 399                 { "f", NULL, },
 400                 { NULL, NULL, },
 401         };
 402
 403         /* quote the path to preserve spaces, etc. */
 404         sq_quote_buf(&path, params->path);
 405         dict[0].value = path.buf;
 406
 407         /* expand all %f with the quoted path */
 408         strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 409         strbuf_release(&path);
 410
 411         argv[0] = cmd.buf;
 412
 413         child_process.argv = argv;
 414         child_process.use_shell = 1;
 415         child_process.in = -1;
 416         child_process.out = out;
 417
 418         if (start_command(&child_process))
 419                 return error("cannot fork to run external filter %s", params->cmd);
 420
 421         sigchain_push(SIGPIPE, SIG_IGN);
 422
 423         if (params->src) {
 424                 write_err = (write_in_full(child_process.in,
 425                                            params->src, params->size) < 0);
 426                 if (errno == EPIPE)
 427                         write_err = 0;
 428         } else {
 429                 write_err = copy_fd(params->fd, child_process.in);
 430                 if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
 431                         write_err = 0;
 432         }
 433
 434         if (close(child_process.in))
 435                 write_err = 1;
 436         if (write_err)
 437                 error("cannot feed the input to external filter %s", params->cmd);
 438
 439         sigchain_pop(SIGPIPE);
 440
 441         status = finish_command(&child_process);
 442         if (status)
 443                 error("external filter %s failed %d", params->cmd, status);
 444
 445         strbuf_release(&cmd);
 446         return (write_err || status);
 447 }
 448
 449 static int apply_filter(const char *path, const char *src, size_t len, int fd,
 450                         struct strbuf *dst, const char *cmd)
 451 {
 452         /*
 453          * Create a pipeline to have the command filter the buffer's
 454          * contents.
 455          *
 456          * (child --> cmd) --> us
 457          */
 458         int ret = 1;
 459         struct strbuf nbuf = STRBUF_INIT;
 460         struct async async;
 461         struct filter_params params;
 462
 463         if (!cmd || !*cmd)
 464                 return 0;
 465
 466         if (!dst)
 467                 return 1;
 468
 469         memset(&async, 0, sizeof(async));
 470         async.proc = filter_buffer_or_fd;
 471         async.data = &params;
 472         async.out = -1;
 473         params.src = src;
 474         params.size = len;
 475         params.fd = fd;
 476         params.cmd = cmd;
 477         params.path = path;
 478
 479         fflush(NULL);
 480         if (start_async(&async))
 481                 return 0;       /* error was already reported */
 482
 483         if (strbuf_read(&nbuf, async.out, len) < 0) {
 484                 error("read from external filter %s failed", cmd);
 485                 ret = 0;
 486         }
 487         if (close(async.out)) {
 488                 error("read from external filter %s failed", cmd);
 489                 ret = 0;
 490         }
 491         if (finish_async(&async)) {
 492                 error("external filter %s failed", cmd);
 493                 ret = 0;
 494         }
 495
 496         if (ret) {
 497                 strbuf_swap(dst, &nbuf);
 498         }
 499         strbuf_release(&nbuf);
 500         return ret;
 501 }
 502
 503 static struct convert_driver {
 504         const char *name;
 505         struct convert_driver *next;
 506         const char *smudge;
 507         const char *clean;
 508         int required;
 509 } *user_convert, **user_convert_tail;
 510
 511 static int read_convert_config(const char *var, const char *value, void *cb)
 512 {
 513         const char *key, *name;
 514         int namelen;
 515         struct convert_driver *drv;
 516
 517         /*
 518          * External conversion drivers are configured using
 519          * "filter.<name>.variable".
 520          */
 521         if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 522                 return 0;
 523         for (drv = user_convert; drv; drv = drv->next)
 524                 if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 525                         break;
 526         if (!drv) {
 527                 drv = xcalloc(1, sizeof(struct convert_driver));
 528                 drv->name = xmemdupz(name, namelen);
 529                 *user_convert_tail = drv;
 530                 user_convert_tail = &(drv->next);
 531         }
 532
 533         /*
 534          * filter.<name>.smudge and filter.<name>.clean specifies
 535          * the command line:
 536          *
 537          *      command-line
 538          *
 539          * The command-line will not be interpolated in any way.
 540          */
 541
 542         if (!strcmp("smudge", key))
 543                 return git_config_string(&drv->smudge, var, value);
 544
 545         if (!strcmp("clean", key))
 546                 return git_config_string(&drv->clean, var, value);
 547
 548         if (!strcmp("required", key)) {
 549                 drv->required = git_config_bool(var, value);
 550                 return 0;
 551         }
 552
 553         return 0;
 554 }
 555
 556 static int count_ident(const char *cp, unsigned long size)
 557 {
 558         /*
 559          * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 560          */
 561         int cnt = 0;
 562         char ch;
 563
 564         while (size) {
 565                 ch = *cp++;
 566                 size--;
 567                 if (ch != '$')
 568                         continue;
 569                 if (size < 3)
 570                         break;
 571                 if (memcmp("Id", cp, 2))
 572                         continue;
 573                 ch = cp[2];
 574                 cp += 3;
 575                 size -= 3;
 576                 if (ch == '$')
 577                         cnt++; /* $Id$ */
 578                 if (ch != ':')
 579                         continue;
 580
 581                 /*
 582                  * "$Id: ... "; scan up to the closing dollar sign and discard.
 583                  */
 584                 while (size) {
 585                         ch = *cp++;
 586                         size--;
 587                         if (ch == '$') {
 588                                 cnt++;
 589                                 break;
 590                         }
 591                         if (ch == '\n')
 592                                 break;
 593                 }
 594         }
 595         return cnt;
 596 }
 597
 598 static int ident_to_git(const char *path, const char *src, size_t len,
 599                         struct strbuf *buf, int ident)
 600 {
 601         char *dst, *dollar;
 602
 603         if (!ident || (src && !count_ident(src, len)))
 604                 return 0;
 605
 606         if (!buf)
 607                 return 1;
 608
 609         /* only grow if not in place */
 610         if (strbuf_avail(buf) + buf->len < len)
 611                 strbuf_grow(buf, len - buf->len);
 612         dst = buf->buf;
 613         for (;;) {
 614                 dollar = memchr(src, '$', len);
 615                 if (!dollar)
 616                         break;
 617                 memmove(dst, src, dollar + 1 - src);
 618                 dst += dollar + 1 - src;
 619                 len -= dollar + 1 - src;
 620                 src  = dollar + 1;
 621
 622                 if (len > 3 && !memcmp(src, "Id:", 3)) {
 623                         dollar = memchr(src + 3, '$', len - 3);
 624                         if (!dollar)
 625                                 break;
 626                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 627                                 /* Line break before the next dollar. */
 628                                 continue;
 629                         }
 630
 631                         memcpy(dst, "Id$", 3);
 632                         dst += 3;
 633                         len -= dollar + 1 - src;
 634                         src  = dollar + 1;
 635                 }
 636         }
 637         memmove(dst, src, len);
 638         strbuf_setlen(buf, dst + len - buf->buf);
 639         return 1;
 640 }
 641
 642 static int ident_to_worktree(const char *path, const char *src, size_t len,
 643                              struct strbuf *buf, int ident)
 644 {
 645         unsigned char sha1[20];
 646         char *to_free = NULL, *dollar, *spc;
 647         int cnt;
 648
 649         if (!ident)
 650                 return 0;
 651
 652         cnt = count_ident(src, len);
 653         if (!cnt)
 654                 return 0;
 655
 656         /* are we "faking" in place editing ? */
 657         if (src == buf->buf)
 658                 to_free = strbuf_detach(buf, NULL);
 659         hash_sha1_file(src, len, "blob", sha1);
 660
 661         strbuf_grow(buf, len + cnt * 43);
 662         for (;;) {
 663                 /* step 1: run to the next '$' */
 664                 dollar = memchr(src, '$', len);
 665                 if (!dollar)
 666                         break;
 667                 strbuf_add(buf, src, dollar + 1 - src);
 668                 len -= dollar + 1 - src;
 669                 src  = dollar + 1;
 670
 671                 /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 672                 if (len < 3 || memcmp("Id", src, 2))
 673                         continue;
 674
 675                 /* step 3: skip over Id$ or Id:xxxxx$ */
 676                 if (src[2] == '$') {
 677                         src += 3;
 678                         len -= 3;
 679                 } else if (src[2] == ':') {
 680                         /*
 681                          * It's possible that an expanded Id has crept its way into the
 682                          * repository, we cope with that by stripping the expansion out.
 683                          * This is probably not a good idea, since it will cause changes
 684                          * on checkout, which won't go away by stash, but let's keep it
 685                          * for git-style ids.
 686                          */
 687                         dollar = memchr(src + 3, '$', len - 3);
 688                         if (!dollar) {
 689                                 /* incomplete keyword, no more '$', so just quit the loop */
 690                                 break;
 691                         }
 692
 693                         if (memchr(src + 3, '\n', dollar - src - 3)) {
 694                                 /* Line break before the next dollar. */
 695                                 continue;
 696                         }
 697
 698                         spc = memchr(src + 4, ' ', dollar - src - 4);
 699                         if (spc && spc < dollar-1) {
 700                                 /* There are spaces in unexpected places.
 701                                  * This is probably an id from some other
 702                                  * versioning system. Keep it for now.
 703                                  */
 704                                 continue;
 705                         }
 706
 707                         len -= dollar + 1 - src;
 708                         src  = dollar + 1;
 709                 } else {
 710                         /* it wasn't a "Id$" or "Id:xxxx$" */
 711                         continue;
 712                 }
 713
 714                 /* step 4: substitute */
 715                 strbuf_addstr(buf, "Id: ");
 716                 strbuf_add(buf, sha1_to_hex(sha1), 40);
 717                 strbuf_addstr(buf, " $");
 718         }
 719         strbuf_add(buf, src, len);
 720
 721         free(to_free);
 722         return 1;
 723 }
 724
 725 static enum crlf_action git_path_check_crlf(struct git_attr_check *check)
 726 {
 727         const char *value = check->value;
 728
 729         if (ATTR_TRUE(value))
 730                 return CRLF_TEXT;
 731         else if (ATTR_FALSE(value))
 732                 return CRLF_BINARY;
 733         else if (ATTR_UNSET(value))
 734                 ;
 735         else if (!strcmp(value, "input"))
 736                 return CRLF_TEXT_INPUT;
 737         else if (!strcmp(value, "auto"))
 738                 return CRLF_AUTO;
 739         return CRLF_UNDEFINED;
 740 }
 741
 742 static enum eol git_path_check_eol(struct git_attr_check *check)
 743 {
 744         const char *value = check->value;
 745
 746         if (ATTR_UNSET(value))
 747                 ;
 748         else if (!strcmp(value, "lf"))
 749                 return EOL_LF;
 750         else if (!strcmp(value, "crlf"))
 751                 return EOL_CRLF;
 752         return EOL_UNSET;
 753 }
 754
 755 static struct convert_driver *git_path_check_convert(struct git_attr_check *check)
 756 {
 757         const char *value = check->value;
 758         struct convert_driver *drv;
 759
 760         if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 761                 return NULL;
 762         for (drv = user_convert; drv; drv = drv->next)
 763                 if (!strcmp(value, drv->name))
 764                         return drv;
 765         return NULL;
 766 }
 767
 768 static int git_path_check_ident(struct git_attr_check *check)
 769 {
 770         const char *value = check->value;
 771
 772         return !!ATTR_TRUE(value);
 773 }
 774
 775 struct conv_attrs {
 776         struct convert_driver *drv;
 777         enum crlf_action attr_action; /* What attr says */
 778         enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
 779         int ident;
 780 };
 781
 782 static const char *conv_attr_name[] = {
 783         "crlf", "ident", "filter", "eol", "text",
 784 };
 785 #define NUM_CONV_ATTRS ARRAY_SIZE(conv_attr_name)
 786
 787 static void convert_attrs(struct conv_attrs *ca, const char *path)
 788 {
 789         int i;
 790         static struct git_attr_check ccheck[NUM_CONV_ATTRS];
 791
 792         if (!ccheck[0].attr) {
 793                 for (i = 0; i < NUM_CONV_ATTRS; i++)
 794                         ccheck[i].attr = git_attr(conv_attr_name[i]);
 795                 user_convert_tail = &user_convert;
 796                 git_config(read_convert_config, NULL);
 797         }
 798
 799         if (!git_check_attr(path, NUM_CONV_ATTRS, ccheck)) {
 800                 ca->crlf_action = git_path_check_crlf(ccheck + 4);
 801                 if (ca->crlf_action == CRLF_UNDEFINED)
 802                         ca->crlf_action = git_path_check_crlf(ccheck + 0);
 803                 ca->attr_action = ca->crlf_action;
 804                 ca->ident = git_path_check_ident(ccheck + 1);
 805                 ca->drv = git_path_check_convert(ccheck + 2);
 806                 if (ca->crlf_action != CRLF_BINARY) {
 807                         enum eol eol_attr = git_path_check_eol(ccheck + 3);
 808                         if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
 809                                 ca->crlf_action = CRLF_AUTO_INPUT;
 810                         else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
 811                                 ca->crlf_action = CRLF_AUTO_CRLF;
 812                         else if (eol_attr == EOL_LF)
 813                                 ca->crlf_action = CRLF_TEXT_INPUT;
 814                         else if (eol_attr == EOL_CRLF)
 815                                 ca->crlf_action = CRLF_TEXT_CRLF;
 816                 }
 817                 ca->attr_action = ca->crlf_action;
 818         } else {
 819                 ca->drv = NULL;
 820                 ca->crlf_action = CRLF_UNDEFINED;
 821                 ca->ident = 0;
 822         }
 823         if (ca->crlf_action == CRLF_TEXT)
 824                 ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
 825         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
 826                 ca->crlf_action = CRLF_BINARY;
 827         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
 828                 ca->crlf_action = CRLF_AUTO_CRLF;
 829         if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
 830                 ca->crlf_action = CRLF_AUTO_INPUT;
 831 }
 832
 833 int would_convert_to_git_filter_fd(const char *path)
 834 {
 835         struct conv_attrs ca;
 836
 837         convert_attrs(&ca, path);
 838         if (!ca.drv)
 839                 return 0;
 840
 841         /*
 842          * Apply a filter to an fd only if the filter is required to succeed.
 843          * We must die if the filter fails, because the original data before
 844          * filtering is not available.
 845          */
 846         if (!ca.drv->required)
 847                 return 0;
 848
 849         return apply_filter(path, NULL, 0, -1, NULL, ca.drv->clean);
 850 }
 851
 852 const char *get_convert_attr_ascii(const char *path)
 853 {
 854         struct conv_attrs ca;
 855
 856         convert_attrs(&ca, path);
 857         switch (ca.attr_action) {
 858         case CRLF_UNDEFINED:
 859                 return "";
 860         case CRLF_BINARY:
 861                 return "-text";
 862         case CRLF_TEXT:
 863                 return "text";
 864         case CRLF_TEXT_INPUT:
 865                 return "text eol=lf";
 866         case CRLF_TEXT_CRLF:
 867                 return "text eol=crlf";
 868         case CRLF_AUTO:
 869                 return "text=auto";
 870         case CRLF_AUTO_CRLF:
 871                 return "text=auto eol=crlf";
 872         case CRLF_AUTO_INPUT:
 873                 return "text=auto eol=lf";
 874         }
 875         return "";
 876 }
 877
 878 int convert_to_git(const char *path, const char *src, size_t len,
 879                    struct strbuf *dst, enum safe_crlf checksafe)
 880 {
 881         int ret = 0;
 882         const char *filter = NULL;
 883         int required = 0;
 884         struct conv_attrs ca;
 885
 886         convert_attrs(&ca, path);
 887         if (ca.drv) {
 888                 filter = ca.drv->clean;
 889                 required = ca.drv->required;
 890         }
 891
 892         ret |= apply_filter(path, src, len, -1, dst, filter);
 893         if (!ret && required)
 894                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 895
 896         if (ret && dst) {
 897                 src = dst->buf;
 898                 len = dst->len;
 899         }
 900         ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
 901         if (ret && dst) {
 902                 src = dst->buf;
 903                 len = dst->len;
 904         }
 905         return ret | ident_to_git(path, src, len, dst, ca.ident);
 906 }
 907
 908 void convert_to_git_filter_fd(const char *path, int fd, struct strbuf *dst,
 909                               enum safe_crlf checksafe)
 910 {
 911         struct conv_attrs ca;
 912         convert_attrs(&ca, path);
 913
 914         assert(ca.drv);
 915         assert(ca.drv->clean);
 916
 917         if (!apply_filter(path, NULL, 0, fd, dst, ca.drv->clean))
 918                 die("%s: clean filter '%s' failed", path, ca.drv->name);
 919
 920         crlf_to_git(path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
 921         ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
 922 }
 923
 924 static int convert_to_working_tree_internal(const char *path, const char *src,
 925                                             size_t len, struct strbuf *dst,
 926                                             int normalizing)
 927 {
 928         int ret = 0, ret_filter = 0;
 929         const char *filter = NULL;
 930         int required = 0;
 931         struct conv_attrs ca;
 932
 933         convert_attrs(&ca, path);
 934         if (ca.drv) {
 935                 filter = ca.drv->smudge;
 936                 required = ca.drv->required;
 937         }
 938
 939         ret |= ident_to_worktree(path, src, len, dst, ca.ident);
 940         if (ret) {
 941                 src = dst->buf;
 942                 len = dst->len;
 943         }
 944         /*
 945          * CRLF conversion can be skipped if normalizing, unless there
 946          * is a smudge filter.  The filter might expect CRLFs.
 947          */
 948         if (filter || !normalizing) {
 949                 ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
 950                 if (ret) {
 951                         src = dst->buf;
 952                         len = dst->len;
 953                 }
 954         }
 955
 956         ret_filter = apply_filter(path, src, len, -1, dst, filter);
 957         if (!ret_filter && required)
 958                 die("%s: smudge filter %s failed", path, ca.drv->name);
 959
 960         return ret | ret_filter;
 961 }
 962
 963 int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 964 {
 965         return convert_to_working_tree_internal(path, src, len, dst, 0);
 966 }
 967
 968 int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
 969 {
 970         int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
 971         if (ret) {
 972                 src = dst->buf;
 973                 len = dst->len;
 974         }
 975         return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_RENORMALIZE);
 976 }
 977
 978 /*****************************************************************
 979  *
 980  * Streaming conversion support
 981  *
 982  *****************************************************************/
 983
 984 typedef int (*filter_fn)(struct stream_filter *,
 985                          const char *input, size_t *isize_p,
 986                          char *output, size_t *osize_p);
 987 typedef void (*free_fn)(struct stream_filter *);
 988
 989 struct stream_filter_vtbl {
 990         filter_fn filter;
 991         free_fn free;
 992 };
 993
 994 struct stream_filter {
 995         struct stream_filter_vtbl *vtbl;
 996 };
 997
 998 static int null_filter_fn(struct stream_filter *filter,
 999                           const char *input, size_t *isize_p,
1000                           char *output, size_t *osize_p)
1001 {
1002         size_t count;
1003
1004         if (!input)
1005                 return 0; /* we do not keep any states */
1006         count = *isize_p;
1007         if (*osize_p < count)
1008                 count = *osize_p;
1009         if (count) {
1010                 memmove(output, input, count);
1011                 *isize_p -= count;
1012                 *osize_p -= count;
1013         }
1014         return 0;
1015 }
1016
1017 static void null_free_fn(struct stream_filter *filter)
1018 {
1019         ; /* nothing -- null instances are shared */
1020 }
1021
1022 static struct stream_filter_vtbl null_vtbl = {
1023         null_filter_fn,
1024         null_free_fn,
1025 };
1026
1027 static struct stream_filter null_filter_singleton = {
1028         &null_vtbl,
1029 };
1030
1031 int is_null_stream_filter(struct stream_filter *filter)
1032 {
1033         return filter == &null_filter_singleton;
1034 }
1035
1036
1037 /*
1038  * LF-to-CRLF filter
1039  */
1040
1041 struct lf_to_crlf_filter {
1042         struct stream_filter filter;
1043         unsigned has_held:1;
1044         char held;
1045 };
1046
1047 static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1048                                 const char *input, size_t *isize_p,
1049                                 char *output, size_t *osize_p)
1050 {
1051         size_t count, o = 0;
1052         struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1053
1054         /*
1055          * We may be holding onto the CR to see if it is followed by a
1056          * LF, in which case we would need to go to the main loop.
1057          * Otherwise, just emit it to the output stream.
1058          */
1059         if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1060                 output[o++] = lf_to_crlf->held;
1061                 lf_to_crlf->has_held = 0;
1062         }
1063
1064         /* We are told to drain */
1065         if (!input) {
1066                 *osize_p -= o;
1067                 return 0;
1068         }
1069
1070         count = *isize_p;
1071         if (count || lf_to_crlf->has_held) {
1072                 size_t i;
1073                 int was_cr = 0;
1074
1075                 if (lf_to_crlf->has_held) {
1076                         was_cr = 1;
1077                         lf_to_crlf->has_held = 0;
1078                 }
1079
1080                 for (i = 0; o < *osize_p && i < count; i++) {
1081                         char ch = input[i];
1082
1083                         if (ch == '\n') {
1084                                 output[o++] = '\r';
1085                         } else if (was_cr) {
1086                                 /*
1087                                  * Previous round saw CR and it is not followed
1088                                  * by a LF; emit the CR before processing the
1089                                  * current character.
1090                                  */
1091                                 output[o++] = '\r';
1092                         }
1093
1094                         /*
1095                          * We may have consumed the last output slot,
1096                          * in which case we need to break out of this
1097                          * loop; hold the current character before
1098                          * returning.
1099                          */
1100                         if (*osize_p <= o) {
1101                                 lf_to_crlf->has_held = 1;
1102                                 lf_to_crlf->held = ch;
1103                                 continue; /* break but increment i */
1104                         }
1105
1106                         if (ch == '\r') {
1107                                 was_cr = 1;
1108                                 continue;
1109                         }
1110
1111                         was_cr = 0;
1112                         output[o++] = ch;
1113                 }
1114
1115                 *osize_p -= o;
1116                 *isize_p -= i;
1117
1118                 if (!lf_to_crlf->has_held && was_cr) {
1119                         lf_to_crlf->has_held = 1;
1120                         lf_to_crlf->held = '\r';
1121                 }
1122         }
1123         return 0;
1124 }
1125
1126 static void lf_to_crlf_free_fn(struct stream_filter *filter)
1127 {
1128         free(filter);
1129 }
1130
1131 static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1132         lf_to_crlf_filter_fn,
1133         lf_to_crlf_free_fn,
1134 };
1135
1136 static struct stream_filter *lf_to_crlf_filter(void)
1137 {
1138         struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1139
1140         lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1141         return (struct stream_filter *)lf_to_crlf;
1142 }
1143
1144 /*
1145  * Cascade filter
1146  */
1147 #define FILTER_BUFFER 1024
1148 struct cascade_filter {
1149         struct stream_filter filter;
1150         struct stream_filter *one;
1151         struct stream_filter *two;
1152         char buf[FILTER_BUFFER];
1153         int end, ptr;
1154 };
1155
1156 static int cascade_filter_fn(struct stream_filter *filter,
1157                              const char *input, size_t *isize_p,
1158                              char *output, size_t *osize_p)
1159 {
1160         struct cascade_filter *cas = (struct cascade_filter *) filter;
1161         size_t filled = 0;
1162         size_t sz = *osize_p;
1163         size_t to_feed, remaining;
1164
1165         /*
1166          * input -- (one) --> buf -- (two) --> output
1167          */
1168         while (filled < sz) {
1169                 remaining = sz - filled;
1170
1171                 /* do we already have something to feed two with? */
1172                 if (cas->ptr < cas->end) {
1173                         to_feed = cas->end - cas->ptr;
1174                         if (stream_filter(cas->two,
1175                                           cas->buf + cas->ptr, &to_feed,
1176                                           output + filled, &remaining))
1177                                 return -1;
1178                         cas->ptr += (cas->end - cas->ptr) - to_feed;
1179                         filled = sz - remaining;
1180                         continue;
1181                 }
1182
1183                 /* feed one from upstream and have it emit into our buffer */
1184                 to_feed = input ? *isize_p : 0;
1185                 if (input && !to_feed)
1186                         break;
1187                 remaining = sizeof(cas->buf);
1188                 if (stream_filter(cas->one,
1189                                   input, &to_feed,
1190                                   cas->buf, &remaining))
1191                         return -1;
1192                 cas->end = sizeof(cas->buf) - remaining;
1193                 cas->ptr = 0;
1194                 if (input) {
1195                         size_t fed = *isize_p - to_feed;
1196                         *isize_p -= fed;
1197                         input += fed;
1198                 }
1199
1200                 /* do we know that we drained one completely? */
1201                 if (input || cas->end)
1202                         continue;
1203
1204                 /* tell two to drain; we have nothing more to give it */
1205                 to_feed = 0;
1206                 remaining = sz - filled;
1207                 if (stream_filter(cas->two,
1208                                   NULL, &to_feed,
1209                                   output + filled, &remaining))
1210                         return -1;
1211                 if (remaining == (sz - filled))
1212                         break; /* completely drained two */
1213                 filled = sz - remaining;
1214         }
1215         *osize_p -= filled;
1216         return 0;
1217 }
1218
1219 static void cascade_free_fn(struct stream_filter *filter)
1220 {
1221         struct cascade_filter *cas = (struct cascade_filter *)filter;
1222         free_stream_filter(cas->one);
1223         free_stream_filter(cas->two);
1224         free(filter);
1225 }
1226
1227 static struct stream_filter_vtbl cascade_vtbl = {
1228         cascade_filter_fn,
1229         cascade_free_fn,
1230 };
1231
1232 static struct stream_filter *cascade_filter(struct stream_filter *one,
1233                                             struct stream_filter *two)
1234 {
1235         struct cascade_filter *cascade;
1236
1237         if (!one || is_null_stream_filter(one))
1238                 return two;
1239         if (!two || is_null_stream_filter(two))
1240                 return one;
1241
1242         cascade = xmalloc(sizeof(*cascade));
1243         cascade->one = one;
1244         cascade->two = two;
1245         cascade->end = cascade->ptr = 0;
1246         cascade->filter.vtbl = &cascade_vtbl;
1247         return (struct stream_filter *)cascade;
1248 }
1249
1250 /*
1251  * ident filter
1252  */
1253 #define IDENT_DRAINING (-1)
1254 #define IDENT_SKIPPING (-2)
1255 struct ident_filter {
1256         struct stream_filter filter;
1257         struct strbuf left;
1258         int state;
1259         char ident[45]; /* ": x40 $" */
1260 };
1261
1262 static int is_foreign_ident(const char *str)
1263 {
1264         int i;
1265
1266         if (!skip_prefix(str, "$Id: ", &str))
1267                 return 0;
1268         for (i = 0; str[i]; i++) {
1269                 if (isspace(str[i]) && str[i+1] != '$')
1270                         return 1;
1271         }
1272         return 0;
1273 }
1274
1275 static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1276 {
1277         size_t to_drain = ident->left.len;
1278
1279         if (*osize_p < to_drain)
1280                 to_drain = *osize_p;
1281         if (to_drain) {
1282                 memcpy(*output_p, ident->left.buf, to_drain);
1283                 strbuf_remove(&ident->left, 0, to_drain);
1284                 *output_p += to_drain;
1285                 *osize_p -= to_drain;
1286         }
1287         if (!ident->left.len)
1288                 ident->state = 0;
1289 }
1290
1291 static int ident_filter_fn(struct stream_filter *filter,
1292                            const char *input, size_t *isize_p,
1293                            char *output, size_t *osize_p)
1294 {
1295         struct ident_filter *ident = (struct ident_filter *)filter;
1296         static const char head[] = "$Id";
1297
1298         if (!input) {
1299                 /* drain upon eof */
1300                 switch (ident->state) {
1301                 default:
1302                         strbuf_add(&ident->left, head, ident->state);
1303                 case IDENT_SKIPPING:
1304                         /* fallthru */
1305                 case IDENT_DRAINING:
1306                         ident_drain(ident, &output, osize_p);
1307                 }
1308                 return 0;
1309         }
1310
1311         while (*isize_p || (ident->state == IDENT_DRAINING)) {
1312                 int ch;
1313
1314                 if (ident->state == IDENT_DRAINING) {
1315                         ident_drain(ident, &output, osize_p);
1316                         if (!*osize_p)
1317                                 break;
1318                         continue;
1319                 }
1320
1321                 ch = *(input++);
1322                 (*isize_p)--;
1323
1324                 if (ident->state == IDENT_SKIPPING) {
1325                         /*
1326                          * Skipping until '$' or LF, but keeping them
1327                          * in case it is a foreign ident.
1328                          */
1329                         strbuf_addch(&ident->left, ch);
1330                         if (ch != '\n' && ch != '$')
1331                                 continue;
1332                         if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1333                                 strbuf_setlen(&ident->left, sizeof(head) - 1);
1334                                 strbuf_addstr(&ident->left, ident->ident);
1335                         }
1336                         ident->state = IDENT_DRAINING;
1337                         continue;
1338                 }
1339
1340                 if (ident->state < sizeof(head) &&
1341                     head[ident->state] == ch) {
1342                         ident->state++;
1343                         continue;
1344                 }
1345
1346                 if (ident->state)
1347                         strbuf_add(&ident->left, head, ident->state);
1348                 if (ident->state == sizeof(head) - 1) {
1349                         if (ch != ':' && ch != '$') {
1350                                 strbuf_addch(&ident->left, ch);
1351                                 ident->state = 0;
1352                                 continue;
1353                         }
1354
1355                         if (ch == ':') {
1356                                 strbuf_addch(&ident->left, ch);
1357                                 ident->state = IDENT_SKIPPING;
1358                         } else {
1359                                 strbuf_addstr(&ident->left, ident->ident);
1360                                 ident->state = IDENT_DRAINING;
1361                         }
1362                         continue;
1363                 }
1364
1365                 strbuf_addch(&ident->left, ch);
1366                 ident->state = IDENT_DRAINING;
1367         }
1368         return 0;
1369 }
1370
1371 static void ident_free_fn(struct stream_filter *filter)
1372 {
1373         struct ident_filter *ident = (struct ident_filter *)filter;
1374         strbuf_release(&ident->left);
1375         free(filter);
1376 }
1377
1378 static struct stream_filter_vtbl ident_vtbl = {
1379         ident_filter_fn,
1380         ident_free_fn,
1381 };
1382
1383 static struct stream_filter *ident_filter(const unsigned char *sha1)
1384 {
1385         struct ident_filter *ident = xmalloc(sizeof(*ident));
1386
1387         xsnprintf(ident->ident, sizeof(ident->ident),
1388                   ": %s $", sha1_to_hex(sha1));
1389         strbuf_init(&ident->left, 0);
1390         ident->filter.vtbl = &ident_vtbl;
1391         ident->state = 0;
1392         return (struct stream_filter *)ident;
1393 }
1394
1395 /*
1396  * Return an appropriately constructed filter for the path, or NULL if
1397  * the contents cannot be filtered without reading the whole thing
1398  * in-core.
1399  *
1400  * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1401  * large binary blob you would want us not to slurp into the memory!
1402  */
1403 struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1404 {
1405         struct conv_attrs ca;
1406         struct stream_filter *filter = NULL;
1407
1408         convert_attrs(&ca, path);
1409         if (ca.drv && (ca.drv->smudge || ca.drv->clean))
1410                 return NULL;
1411
1412         if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1413                 return NULL;
1414
1415         if (ca.ident)
1416                 filter = ident_filter(sha1);
1417
1418         if (output_eol(ca.crlf_action) == EOL_CRLF)
1419                 filter = cascade_filter(filter, lf_to_crlf_filter());
1420         else
1421                 filter = cascade_filter(filter, &null_filter_singleton);
1422
1423         return filter;
1424 }
1425
1426 void free_stream_filter(struct stream_filter *filter)
1427 {
1428         filter->vtbl->free(filter);
1429 }
1430
1431 int stream_filter(struct stream_filter *filter,
1432                   const char *input, size_t *isize_p,
1433                   char *output, size_t *osize_p)
1434 {
1435         return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1436 }