Andrew's git / gitweb.git / convert.c
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convert.con commit Merge branch 'np/pack' (cc93020)
   1#include "cache.h"
   2#include "attr.h"
   3#include "run-command.h"
   4
   5/*
   6 * convert.c - convert a file when checking it out and checking it in.
   7 *
   8 * This should use the pathname to decide on whether it wants to do some
   9 * more interesting conversions (automatic gzip/unzip, general format
  10 * conversions etc etc), but by default it just does automatic CRLF<->LF
  11 * translation when the "auto_crlf" option is set.
  12 */
  13
  14#define CRLF_GUESS      (-1)
  15#define CRLF_BINARY     0
  16#define CRLF_TEXT       1
  17#define CRLF_INPUT      2
  18
  19struct text_stat {
  20        /* CR, LF and CRLF counts */
  21        unsigned cr, lf, crlf;
  22
  23        /* These are just approximations! */
  24        unsigned printable, nonprintable;
  25};
  26
  27static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  28{
  29        unsigned long i;
  30
  31        memset(stats, 0, sizeof(*stats));
  32
  33        for (i = 0; i < size; i++) {
  34                unsigned char c = buf[i];
  35                if (c == '\r') {
  36                        stats->cr++;
  37                        if (i+1 < size && buf[i+1] == '\n')
  38                                stats->crlf++;
  39                        continue;
  40                }
  41                if (c == '\n') {
  42                        stats->lf++;
  43                        continue;
  44                }
  45                if (c == 127)
  46                        /* DEL */
  47                        stats->nonprintable++;
  48                else if (c < 32) {
  49                        switch (c) {
  50                                /* BS, HT, ESC and FF */
  51                        case '\b': case '\t': case '\033': case '\014':
  52                                stats->printable++;
  53                                break;
  54                        default:
  55                                stats->nonprintable++;
  56                        }
  57                }
  58                else
  59                        stats->printable++;
  60        }
  61}
  62
  63/*
  64 * The same heuristics as diff.c::mmfile_is_binary()
  65 */
  66static int is_binary(unsigned long size, struct text_stat *stats)
  67{
  68
  69        if ((stats->printable >> 7) < stats->nonprintable)
  70                return 1;
  71        /*
  72         * Other heuristics? Average line length might be relevant,
  73         * as might LF vs CR vs CRLF counts..
  74         *
  75         * NOTE! It might be normal to have a low ratio of CRLF to LF
  76         * (somebody starts with a LF-only file and edits it with an editor
  77         * that adds CRLF only to lines that are added..). But do  we
  78         * want to support CR-only? Probably not.
  79         */
  80        return 0;
  81}
  82
  83static char *crlf_to_git(const char *path, const char *src, unsigned long *sizep, int action)
  84{
  85        char *buffer, *dst;
  86        unsigned long size, nsize;
  87        struct text_stat stats;
  88
  89        if ((action == CRLF_BINARY) || !auto_crlf)
  90                return NULL;
  91
  92        size = *sizep;
  93        if (!size)
  94                return NULL;
  95
  96        gather_stats(src, size, &stats);
  97
  98        /* No CR? Nothing to convert, regardless. */
  99        if (!stats.cr)
 100                return NULL;
 101
 102        if (action == CRLF_GUESS) {
 103                /*
 104                 * We're currently not going to even try to convert stuff
 105                 * that has bare CR characters. Does anybody do that crazy
 106                 * stuff?
 107                 */
 108                if (stats.cr != stats.crlf)
 109                        return NULL;
 110
 111                /*
 112                 * And add some heuristics for binary vs text, of course...
 113                 */
 114                if (is_binary(size, &stats))
 115                        return NULL;
 116        }
 117
 118        /*
 119         * Ok, allocate a new buffer, fill it in, and return it
 120         * to let the caller know that we switched buffers.
 121         */
 122        nsize = size - stats.crlf;
 123        buffer = xmalloc(nsize);
 124        *sizep = nsize;
 125
 126        dst = buffer;
 127        if (action == CRLF_GUESS) {
 128                /*
 129                 * If we guessed, we already know we rejected a file with
 130                 * lone CR, and we can strip a CR without looking at what
 131                 * follow it.
 132                 */
 133                do {
 134                        unsigned char c = *src++;
 135                        if (c != '\r')
 136                                *dst++ = c;
 137                } while (--size);
 138        } else {
 139                do {
 140                        unsigned char c = *src++;
 141                        if (! (c == '\r' && (1 < size && *src == '\n')))
 142                                *dst++ = c;
 143                } while (--size);
 144        }
 145
 146        return buffer;
 147}
 148
 149static char *crlf_to_worktree(const char *path, const char *src, unsigned long *sizep, int action)
 150{
 151        char *buffer, *dst;
 152        unsigned long size, nsize;
 153        struct text_stat stats;
 154        unsigned char last;
 155
 156        if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
 157            auto_crlf <= 0)
 158                return NULL;
 159
 160        size = *sizep;
 161        if (!size)
 162                return NULL;
 163
 164        gather_stats(src, size, &stats);
 165
 166        /* No LF? Nothing to convert, regardless. */
 167        if (!stats.lf)
 168                return NULL;
 169
 170        /* Was it already in CRLF format? */
 171        if (stats.lf == stats.crlf)
 172                return NULL;
 173
 174        if (action == CRLF_GUESS) {
 175                /* If we have any bare CR characters, we're not going to touch it */
 176                if (stats.cr != stats.crlf)
 177                        return NULL;
 178
 179                if (is_binary(size, &stats))
 180                        return NULL;
 181        }
 182
 183        /*
 184         * Ok, allocate a new buffer, fill it in, and return it
 185         * to let the caller know that we switched buffers.
 186         */
 187        nsize = size + stats.lf - stats.crlf;
 188        buffer = xmalloc(nsize);
 189        *sizep = nsize;
 190        last = 0;
 191
 192        dst = buffer;
 193        do {
 194                unsigned char c = *src++;
 195                if (c == '\n' && last != '\r')
 196                        *dst++ = '\r';
 197                *dst++ = c;
 198                last = c;
 199        } while (--size);
 200
 201        return buffer;
 202}
 203
 204static int filter_buffer(const char *path, const char *src,
 205                         unsigned long size, const char *cmd)
 206{
 207        /*
 208         * Spawn cmd and feed the buffer contents through its stdin.
 209         */
 210        struct child_process child_process;
 211        int pipe_feed[2];
 212        int write_err, status;
 213
 214        memset(&child_process, 0, sizeof(child_process));
 215
 216        if (pipe(pipe_feed) < 0) {
 217                error("cannot create pipe to run external filter %s", cmd);
 218                return 1;
 219        }
 220
 221        child_process.pid = fork();
 222        if (child_process.pid < 0) {
 223                error("cannot fork to run external filter %s", cmd);
 224                close(pipe_feed[0]);
 225                close(pipe_feed[1]);
 226                return 1;
 227        }
 228        if (!child_process.pid) {
 229                dup2(pipe_feed[0], 0);
 230                close(pipe_feed[0]);
 231                close(pipe_feed[1]);
 232                execlp("sh", "sh", "-c", cmd, NULL);
 233                return 1;
 234        }
 235        close(pipe_feed[0]);
 236
 237        write_err = (write_in_full(pipe_feed[1], src, size) < 0);
 238        if (close(pipe_feed[1]))
 239                write_err = 1;
 240        if (write_err)
 241                error("cannot feed the input to external filter %s", cmd);
 242
 243        status = finish_command(&child_process);
 244        if (status)
 245                error("external filter %s failed %d", cmd, -status);
 246        return (write_err || status);
 247}
 248
 249static char *apply_filter(const char *path, const char *src,
 250                          unsigned long *sizep, const char *cmd)
 251{
 252        /*
 253         * Create a pipeline to have the command filter the buffer's
 254         * contents.
 255         *
 256         * (child --> cmd) --> us
 257         */
 258        const int SLOP = 4096;
 259        int pipe_feed[2];
 260        int status;
 261        char *dst;
 262        unsigned long dstsize, dstalloc;
 263        struct child_process child_process;
 264
 265        if (!cmd)
 266                return NULL;
 267
 268        memset(&child_process, 0, sizeof(child_process));
 269
 270        if (pipe(pipe_feed) < 0) {
 271                error("cannot create pipe to run external filter %s", cmd);
 272                return NULL;
 273        }
 274
 275        fflush(NULL);
 276        child_process.pid = fork();
 277        if (child_process.pid < 0) {
 278                error("cannot fork to run external filter %s", cmd);
 279                close(pipe_feed[0]);
 280                close(pipe_feed[1]);
 281                return NULL;
 282        }
 283        if (!child_process.pid) {
 284                dup2(pipe_feed[1], 1);
 285                close(pipe_feed[0]);
 286                close(pipe_feed[1]);
 287                exit(filter_buffer(path, src, *sizep, cmd));
 288        }
 289        close(pipe_feed[1]);
 290
 291        dstalloc = *sizep;
 292        dst = xmalloc(dstalloc);
 293        dstsize = 0;
 294
 295        while (1) {
 296                ssize_t numread = xread(pipe_feed[0], dst + dstsize,
 297                                        dstalloc - dstsize);
 298
 299                if (numread <= 0) {
 300                        if (!numread)
 301                                break;
 302                        error("read from external filter %s failed", cmd);
 303                        free(dst);
 304                        dst = NULL;
 305                        break;
 306                }
 307                dstsize += numread;
 308                if (dstalloc <= dstsize + SLOP) {
 309                        dstalloc = dstsize + SLOP;
 310                        dst = xrealloc(dst, dstalloc);
 311                }
 312        }
 313        if (close(pipe_feed[0])) {
 314                error("read from external filter %s failed", cmd);
 315                free(dst);
 316                dst = NULL;
 317        }
 318
 319        status = finish_command(&child_process);
 320        if (status) {
 321                error("external filter %s failed %d", cmd, -status);
 322                free(dst);
 323                dst = NULL;
 324        }
 325
 326        if (dst)
 327                *sizep = dstsize;
 328        return dst;
 329}
 330
 331static struct convert_driver {
 332        const char *name;
 333        struct convert_driver *next;
 334        char *smudge;
 335        char *clean;
 336} *user_convert, **user_convert_tail;
 337
 338static int read_convert_config(const char *var, const char *value)
 339{
 340        const char *ep, *name;
 341        int namelen;
 342        struct convert_driver *drv;
 343
 344        /*
 345         * External conversion drivers are configured using
 346         * "filter.<name>.variable".
 347         */
 348        if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
 349                return 0;
 350        name = var + 7;
 351        namelen = ep - name;
 352        for (drv = user_convert; drv; drv = drv->next)
 353                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 354                        break;
 355        if (!drv) {
 356                char *namebuf;
 357                drv = xcalloc(1, sizeof(struct convert_driver));
 358                namebuf = xmalloc(namelen + 1);
 359                memcpy(namebuf, name, namelen);
 360                namebuf[namelen] = 0;
 361                drv->name = namebuf;
 362                drv->next = NULL;
 363                *user_convert_tail = drv;
 364                user_convert_tail = &(drv->next);
 365        }
 366
 367        ep++;
 368
 369        /*
 370         * filter.<name>.smudge and filter.<name>.clean specifies
 371         * the command line:
 372         *
 373         *      command-line
 374         *
 375         * The command-line will not be interpolated in any way.
 376         */
 377
 378        if (!strcmp("smudge", ep)) {
 379                if (!value)
 380                        return error("%s: lacks value", var);
 381                drv->smudge = strdup(value);
 382                return 0;
 383        }
 384
 385        if (!strcmp("clean", ep)) {
 386                if (!value)
 387                        return error("%s: lacks value", var);
 388                drv->clean = strdup(value);
 389                return 0;
 390        }
 391        return 0;
 392}
 393
 394static void setup_convert_check(struct git_attr_check *check)
 395{
 396        static struct git_attr *attr_crlf;
 397        static struct git_attr *attr_ident;
 398        static struct git_attr *attr_filter;
 399
 400        if (!attr_crlf) {
 401                attr_crlf = git_attr("crlf", 4);
 402                attr_ident = git_attr("ident", 5);
 403                attr_filter = git_attr("filter", 6);
 404                user_convert_tail = &user_convert;
 405                git_config(read_convert_config);
 406        }
 407        check[0].attr = attr_crlf;
 408        check[1].attr = attr_ident;
 409        check[2].attr = attr_filter;
 410}
 411
 412static int count_ident(const char *cp, unsigned long size)
 413{
 414        /*
 415         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 416         */
 417        int cnt = 0;
 418        char ch;
 419
 420        while (size) {
 421                ch = *cp++;
 422                size--;
 423                if (ch != '$')
 424                        continue;
 425                if (size < 3)
 426                        break;
 427                if (memcmp("Id", cp, 2))
 428                        continue;
 429                ch = cp[2];
 430                cp += 3;
 431                size -= 3;
 432                if (ch == '$')
 433                        cnt++; /* $Id$ */
 434                if (ch != ':')
 435                        continue;
 436
 437                /*
 438                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 439                 */
 440                while (size) {
 441                        ch = *cp++;
 442                        size--;
 443                        if (ch == '$') {
 444                                cnt++;
 445                                break;
 446                        }
 447                }
 448        }
 449        return cnt;
 450}
 451
 452static char *ident_to_git(const char *path, const char *src, unsigned long *sizep, int ident)
 453{
 454        int cnt;
 455        unsigned long size;
 456        char *dst, *buf;
 457
 458        if (!ident)
 459                return NULL;
 460        size = *sizep;
 461        cnt = count_ident(src, size);
 462        if (!cnt)
 463                return NULL;
 464        buf = xmalloc(size);
 465
 466        for (dst = buf; size; size--) {
 467                char ch = *src++;
 468                *dst++ = ch;
 469                if ((ch == '$') && (3 <= size) &&
 470                    !memcmp("Id:", src, 3)) {
 471                        unsigned long rem = size - 3;
 472                        const char *cp = src + 3;
 473                        do {
 474                                ch = *cp++;
 475                                if (ch == '$')
 476                                        break;
 477                                rem--;
 478                        } while (rem);
 479                        if (!rem)
 480                                continue;
 481                        memcpy(dst, "Id$", 3);
 482                        dst += 3;
 483                        size -= (cp - src);
 484                        src = cp;
 485                }
 486        }
 487
 488        *sizep = dst - buf;
 489        return buf;
 490}
 491
 492static char *ident_to_worktree(const char *path, const char *src, unsigned long *sizep, int ident)
 493{
 494        int cnt;
 495        unsigned long size;
 496        char *dst, *buf;
 497        unsigned char sha1[20];
 498
 499        if (!ident)
 500                return NULL;
 501
 502        size = *sizep;
 503        cnt = count_ident(src, size);
 504        if (!cnt)
 505                return NULL;
 506
 507        hash_sha1_file(src, size, "blob", sha1);
 508        buf = xmalloc(size + cnt * 43);
 509
 510        for (dst = buf; size; size--) {
 511                const char *cp;
 512                char ch = *src++;
 513                *dst++ = ch;
 514                if ((ch != '$') || (size < 3) || memcmp("Id", src, 2))
 515                        continue;
 516
 517                if (src[2] == ':') {
 518                        /* discard up to but not including the closing $ */
 519                        unsigned long rem = size - 3;
 520                        cp = src + 3;
 521                        do {
 522                                ch = *cp++;
 523                                if (ch == '$')
 524                                        break;
 525                                rem--;
 526                        } while (rem);
 527                        if (!rem)
 528                                continue;
 529                        size -= (cp - src);
 530                } else if (src[2] == '$')
 531                        cp = src + 2;
 532                else
 533                        continue;
 534
 535                memcpy(dst, "Id: ", 4);
 536                dst += 4;
 537                memcpy(dst, sha1_to_hex(sha1), 40);
 538                dst += 40;
 539                *dst++ = ' ';
 540                size -= (cp - src);
 541                src = cp;
 542                *dst++ = *src++;
 543                size--;
 544        }
 545
 546        *sizep = dst - buf;
 547        return buf;
 548}
 549
 550static int git_path_check_crlf(const char *path, struct git_attr_check *check)
 551{
 552        const char *value = check->value;
 553
 554        if (ATTR_TRUE(value))
 555                return CRLF_TEXT;
 556        else if (ATTR_FALSE(value))
 557                return CRLF_BINARY;
 558        else if (ATTR_UNSET(value))
 559                ;
 560        else if (!strcmp(value, "input"))
 561                return CRLF_INPUT;
 562        return CRLF_GUESS;
 563}
 564
 565static struct convert_driver *git_path_check_convert(const char *path,
 566                                             struct git_attr_check *check)
 567{
 568        const char *value = check->value;
 569        struct convert_driver *drv;
 570
 571        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 572                return NULL;
 573        for (drv = user_convert; drv; drv = drv->next)
 574                if (!strcmp(value, drv->name))
 575                        return drv;
 576        return NULL;
 577}
 578
 579static int git_path_check_ident(const char *path, struct git_attr_check *check)
 580{
 581        const char *value = check->value;
 582
 583        return !!ATTR_TRUE(value);
 584}
 585
 586char *convert_to_git(const char *path, const char *src, unsigned long *sizep)
 587{
 588        struct git_attr_check check[3];
 589        int crlf = CRLF_GUESS;
 590        int ident = 0;
 591        char *filter = NULL;
 592        char *buf, *buf2;
 593
 594        setup_convert_check(check);
 595        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 596                struct convert_driver *drv;
 597                crlf = git_path_check_crlf(path, check + 0);
 598                ident = git_path_check_ident(path, check + 1);
 599                drv = git_path_check_convert(path, check + 2);
 600                if (drv && drv->clean)
 601                        filter = drv->clean;
 602        }
 603
 604        buf = apply_filter(path, src, sizep, filter);
 605
 606        buf2 = crlf_to_git(path, buf ? buf : src, sizep, crlf);
 607        if (buf2) {
 608                free(buf);
 609                buf = buf2;
 610        }
 611
 612        buf2 = ident_to_git(path, buf ? buf : src, sizep, ident);
 613        if (buf2) {
 614                free(buf);
 615                buf = buf2;
 616        }
 617
 618        return buf;
 619}
 620
 621char *convert_to_working_tree(const char *path, const char *src, unsigned long *sizep)
 622{
 623        struct git_attr_check check[3];
 624        int crlf = CRLF_GUESS;
 625        int ident = 0;
 626        char *filter = NULL;
 627        char *buf, *buf2;
 628
 629        setup_convert_check(check);
 630        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 631                struct convert_driver *drv;
 632                crlf = git_path_check_crlf(path, check + 0);
 633                ident = git_path_check_ident(path, check + 1);
 634                drv = git_path_check_convert(path, check + 2);
 635                if (drv && drv->smudge)
 636                        filter = drv->smudge;
 637        }
 638
 639        buf = ident_to_worktree(path, src, sizep, ident);
 640
 641        buf2 = crlf_to_worktree(path, buf ? buf : src, sizep, crlf);
 642        if (buf2) {
 643                free(buf);
 644                buf = buf2;
 645        }
 646
 647        buf2 = apply_filter(path, buf ? buf : src, sizep, filter);
 648        if (buf2) {
 649                free(buf);
 650                buf = buf2;
 651        }
 652
 653        return buf;
 654}
 655
 656void *convert_sha1_file(const char *path, const unsigned char *sha1,
 657                        unsigned int mode, enum object_type *type,
 658                        unsigned long *size)
 659{
 660        void *buffer = read_sha1_file(sha1, type, size);
 661        if (S_ISREG(mode) && buffer) {
 662                void *converted = convert_to_working_tree(path, buffer, size);
 663                if (converted) {
 664                        free(buffer);
 665                        buffer = converted;
 666                }
 667        }
 668        return buffer;
 669}