Andrew's git / gitweb.git / convert.c
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convert.con commit Merge branch 'ds/gitweb' into HEAD (791e421)
   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 int crlf_to_git(const char *path, const char *src, size_t len,
  84                       struct strbuf *buf, int action)
  85{
  86        struct text_stat stats;
  87        char *dst;
  88
  89        if ((action == CRLF_BINARY) || !auto_crlf || !len)
  90                return 0;
  91
  92        gather_stats(src, len, &stats);
  93        /* No CR? Nothing to convert, regardless. */
  94        if (!stats.cr)
  95                return 0;
  96
  97        if (action == CRLF_GUESS) {
  98                /*
  99                 * We're currently not going to even try to convert stuff
 100                 * that has bare CR characters. Does anybody do that crazy
 101                 * stuff?
 102                 */
 103                if (stats.cr != stats.crlf)
 104                        return 0;
 105
 106                /*
 107                 * And add some heuristics for binary vs text, of course...
 108                 */
 109                if (is_binary(len, &stats))
 110                        return 0;
 111        }
 112
 113        /* only grow if not in place */
 114        if (strbuf_avail(buf) + buf->len < len)
 115                strbuf_grow(buf, len - buf->len);
 116        dst = buf->buf;
 117        if (action == CRLF_GUESS) {
 118                /*
 119                 * If we guessed, we already know we rejected a file with
 120                 * lone CR, and we can strip a CR without looking at what
 121                 * follow it.
 122                 */
 123                do {
 124                        unsigned char c = *src++;
 125                        if (c != '\r')
 126                                *dst++ = c;
 127                } while (--len);
 128        } else {
 129                do {
 130                        unsigned char c = *src++;
 131                        if (! (c == '\r' && (1 < len && *src == '\n')))
 132                                *dst++ = c;
 133                } while (--len);
 134        }
 135        strbuf_setlen(buf, dst - buf->buf);
 136        return 1;
 137}
 138
 139static int crlf_to_worktree(const char *path, const char *src, size_t len,
 140                            struct strbuf *buf, int action)
 141{
 142        char *to_free = NULL;
 143        struct text_stat stats;
 144
 145        if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
 146            auto_crlf <= 0)
 147                return 0;
 148
 149        if (!len)
 150                return 0;
 151
 152        gather_stats(src, len, &stats);
 153
 154        /* No LF? Nothing to convert, regardless. */
 155        if (!stats.lf)
 156                return 0;
 157
 158        /* Was it already in CRLF format? */
 159        if (stats.lf == stats.crlf)
 160                return 0;
 161
 162        if (action == CRLF_GUESS) {
 163                /* If we have any bare CR characters, we're not going to touch it */
 164                if (stats.cr != stats.crlf)
 165                        return 0;
 166
 167                if (is_binary(len, &stats))
 168                        return 0;
 169        }
 170
 171        /* are we "faking" in place editing ? */
 172        if (src == buf->buf)
 173                to_free = strbuf_detach(buf, NULL);
 174
 175        strbuf_grow(buf, len + stats.lf - stats.crlf);
 176        for (;;) {
 177                const char *nl = memchr(src, '\n', len);
 178                if (!nl)
 179                        break;
 180                if (nl > src && nl[-1] == '\r') {
 181                        strbuf_add(buf, src, nl + 1 - src);
 182                } else {
 183                        strbuf_add(buf, src, nl - src);
 184                        strbuf_addstr(buf, "\r\n");
 185                }
 186                len -= nl + 1 - src;
 187                src  = nl + 1;
 188        }
 189        strbuf_add(buf, src, len);
 190
 191        free(to_free);
 192        return 1;
 193}
 194
 195static int filter_buffer(const char *path, const char *src,
 196                         unsigned long size, const char *cmd)
 197{
 198        /*
 199         * Spawn cmd and feed the buffer contents through its stdin.
 200         */
 201        struct child_process child_process;
 202        int pipe_feed[2];
 203        int write_err, status;
 204
 205        memset(&child_process, 0, sizeof(child_process));
 206
 207        if (pipe(pipe_feed) < 0) {
 208                error("cannot create pipe to run external filter %s", cmd);
 209                return 1;
 210        }
 211
 212        child_process.pid = fork();
 213        if (child_process.pid < 0) {
 214                error("cannot fork to run external filter %s", cmd);
 215                close(pipe_feed[0]);
 216                close(pipe_feed[1]);
 217                return 1;
 218        }
 219        if (!child_process.pid) {
 220                dup2(pipe_feed[0], 0);
 221                close(pipe_feed[0]);
 222                close(pipe_feed[1]);
 223                execlp("sh", "sh", "-c", cmd, NULL);
 224                return 1;
 225        }
 226        close(pipe_feed[0]);
 227
 228        write_err = (write_in_full(pipe_feed[1], src, size) < 0);
 229        if (close(pipe_feed[1]))
 230                write_err = 1;
 231        if (write_err)
 232                error("cannot feed the input to external filter %s", cmd);
 233
 234        status = finish_command(&child_process);
 235        if (status)
 236                error("external filter %s failed %d", cmd, -status);
 237        return (write_err || status);
 238}
 239
 240static int apply_filter(const char *path, const char *src, size_t len,
 241                        struct strbuf *dst, const char *cmd)
 242{
 243        /*
 244         * Create a pipeline to have the command filter the buffer's
 245         * contents.
 246         *
 247         * (child --> cmd) --> us
 248         */
 249        int pipe_feed[2];
 250        int status, ret = 1;
 251        struct child_process child_process;
 252        struct strbuf nbuf;
 253
 254        if (!cmd)
 255                return 0;
 256
 257        memset(&child_process, 0, sizeof(child_process));
 258
 259        if (pipe(pipe_feed) < 0) {
 260                error("cannot create pipe to run external filter %s", cmd);
 261                return 0;
 262        }
 263
 264        fflush(NULL);
 265        child_process.pid = fork();
 266        if (child_process.pid < 0) {
 267                error("cannot fork to run external filter %s", cmd);
 268                close(pipe_feed[0]);
 269                close(pipe_feed[1]);
 270                return 0;
 271        }
 272        if (!child_process.pid) {
 273                dup2(pipe_feed[1], 1);
 274                close(pipe_feed[0]);
 275                close(pipe_feed[1]);
 276                exit(filter_buffer(path, src, len, cmd));
 277        }
 278        close(pipe_feed[1]);
 279
 280        strbuf_init(&nbuf, 0);
 281        if (strbuf_read(&nbuf, pipe_feed[0], len) < 0) {
 282                error("read from external filter %s failed", cmd);
 283                ret = 0;
 284        }
 285        if (close(pipe_feed[0])) {
 286                error("read from external filter %s failed", cmd);
 287                ret = 0;
 288        }
 289        status = finish_command(&child_process);
 290        if (status) {
 291                error("external filter %s failed %d", cmd, -status);
 292                ret = 0;
 293        }
 294
 295        if (ret) {
 296                strbuf_swap(dst, &nbuf);
 297        }
 298        strbuf_release(&nbuf);
 299        return ret;
 300}
 301
 302static struct convert_driver {
 303        const char *name;
 304        struct convert_driver *next;
 305        char *smudge;
 306        char *clean;
 307} *user_convert, **user_convert_tail;
 308
 309static int read_convert_config(const char *var, const char *value)
 310{
 311        const char *ep, *name;
 312        int namelen;
 313        struct convert_driver *drv;
 314
 315        /*
 316         * External conversion drivers are configured using
 317         * "filter.<name>.variable".
 318         */
 319        if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
 320                return 0;
 321        name = var + 7;
 322        namelen = ep - name;
 323        for (drv = user_convert; drv; drv = drv->next)
 324                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 325                        break;
 326        if (!drv) {
 327                drv = xcalloc(1, sizeof(struct convert_driver));
 328                drv->name = xmemdupz(name, namelen);
 329                *user_convert_tail = drv;
 330                user_convert_tail = &(drv->next);
 331        }
 332
 333        ep++;
 334
 335        /*
 336         * filter.<name>.smudge and filter.<name>.clean specifies
 337         * the command line:
 338         *
 339         *      command-line
 340         *
 341         * The command-line will not be interpolated in any way.
 342         */
 343
 344        if (!strcmp("smudge", ep)) {
 345                if (!value)
 346                        return error("%s: lacks value", var);
 347                drv->smudge = strdup(value);
 348                return 0;
 349        }
 350
 351        if (!strcmp("clean", ep)) {
 352                if (!value)
 353                        return error("%s: lacks value", var);
 354                drv->clean = strdup(value);
 355                return 0;
 356        }
 357        return 0;
 358}
 359
 360static void setup_convert_check(struct git_attr_check *check)
 361{
 362        static struct git_attr *attr_crlf;
 363        static struct git_attr *attr_ident;
 364        static struct git_attr *attr_filter;
 365
 366        if (!attr_crlf) {
 367                attr_crlf = git_attr("crlf", 4);
 368                attr_ident = git_attr("ident", 5);
 369                attr_filter = git_attr("filter", 6);
 370                user_convert_tail = &user_convert;
 371                git_config(read_convert_config);
 372        }
 373        check[0].attr = attr_crlf;
 374        check[1].attr = attr_ident;
 375        check[2].attr = attr_filter;
 376}
 377
 378static int count_ident(const char *cp, unsigned long size)
 379{
 380        /*
 381         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 382         */
 383        int cnt = 0;
 384        char ch;
 385
 386        while (size) {
 387                ch = *cp++;
 388                size--;
 389                if (ch != '$')
 390                        continue;
 391                if (size < 3)
 392                        break;
 393                if (memcmp("Id", cp, 2))
 394                        continue;
 395                ch = cp[2];
 396                cp += 3;
 397                size -= 3;
 398                if (ch == '$')
 399                        cnt++; /* $Id$ */
 400                if (ch != ':')
 401                        continue;
 402
 403                /*
 404                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 405                 */
 406                while (size) {
 407                        ch = *cp++;
 408                        size--;
 409                        if (ch == '$') {
 410                                cnt++;
 411                                break;
 412                        }
 413                }
 414        }
 415        return cnt;
 416}
 417
 418static int ident_to_git(const char *path, const char *src, size_t len,
 419                        struct strbuf *buf, int ident)
 420{
 421        char *dst, *dollar;
 422
 423        if (!ident || !count_ident(src, len))
 424                return 0;
 425
 426        /* only grow if not in place */
 427        if (strbuf_avail(buf) + buf->len < len)
 428                strbuf_grow(buf, len - buf->len);
 429        dst = buf->buf;
 430        for (;;) {
 431                dollar = memchr(src, '$', len);
 432                if (!dollar)
 433                        break;
 434                memcpy(dst, src, dollar + 1 - src);
 435                dst += dollar + 1 - src;
 436                len -= dollar + 1 - src;
 437                src  = dollar + 1;
 438
 439                if (len > 3 && !memcmp(src, "Id:", 3)) {
 440                        dollar = memchr(src + 3, '$', len - 3);
 441                        if (!dollar)
 442                                break;
 443                        memcpy(dst, "Id$", 3);
 444                        dst += 3;
 445                        len -= dollar + 1 - src;
 446                        src  = dollar + 1;
 447                }
 448        }
 449        memcpy(dst, src, len);
 450        strbuf_setlen(buf, dst + len - buf->buf);
 451        return 1;
 452}
 453
 454static int ident_to_worktree(const char *path, const char *src, size_t len,
 455                             struct strbuf *buf, int ident)
 456{
 457        unsigned char sha1[20];
 458        char *to_free = NULL, *dollar;
 459        int cnt;
 460
 461        if (!ident)
 462                return 0;
 463
 464        cnt = count_ident(src, len);
 465        if (!cnt)
 466                return 0;
 467
 468        /* are we "faking" in place editing ? */
 469        if (src == buf->buf)
 470                to_free = strbuf_detach(buf, NULL);
 471        hash_sha1_file(src, len, "blob", sha1);
 472
 473        strbuf_grow(buf, len + cnt * 43);
 474        for (;;) {
 475                /* step 1: run to the next '$' */
 476                dollar = memchr(src, '$', len);
 477                if (!dollar)
 478                        break;
 479                strbuf_add(buf, src, dollar + 1 - src);
 480                len -= dollar + 1 - src;
 481                src  = dollar + 1;
 482
 483                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 484                if (len < 3 || memcmp("Id", src, 2))
 485                        continue;
 486
 487                /* step 3: skip over Id$ or Id:xxxxx$ */
 488                if (src[2] == '$') {
 489                        src += 3;
 490                        len -= 3;
 491                } else if (src[2] == ':') {
 492                        /*
 493                         * It's possible that an expanded Id has crept its way into the
 494                         * repository, we cope with that by stripping the expansion out
 495                         */
 496                        dollar = memchr(src + 3, '$', len - 3);
 497                        if (!dollar) {
 498                                /* incomplete keyword, no more '$', so just quit the loop */
 499                                break;
 500                        }
 501
 502                        len -= dollar + 1 - src;
 503                        src  = dollar + 1;
 504                } else {
 505                        /* it wasn't a "Id$" or "Id:xxxx$" */
 506                        continue;
 507                }
 508
 509                /* step 4: substitute */
 510                strbuf_addstr(buf, "Id: ");
 511                strbuf_add(buf, sha1_to_hex(sha1), 40);
 512                strbuf_addstr(buf, " $");
 513        }
 514        strbuf_add(buf, src, len);
 515
 516        free(to_free);
 517        return 1;
 518}
 519
 520static int git_path_check_crlf(const char *path, struct git_attr_check *check)
 521{
 522        const char *value = check->value;
 523
 524        if (ATTR_TRUE(value))
 525                return CRLF_TEXT;
 526        else if (ATTR_FALSE(value))
 527                return CRLF_BINARY;
 528        else if (ATTR_UNSET(value))
 529                ;
 530        else if (!strcmp(value, "input"))
 531                return CRLF_INPUT;
 532        return CRLF_GUESS;
 533}
 534
 535static struct convert_driver *git_path_check_convert(const char *path,
 536                                             struct git_attr_check *check)
 537{
 538        const char *value = check->value;
 539        struct convert_driver *drv;
 540
 541        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 542                return NULL;
 543        for (drv = user_convert; drv; drv = drv->next)
 544                if (!strcmp(value, drv->name))
 545                        return drv;
 546        return NULL;
 547}
 548
 549static int git_path_check_ident(const char *path, struct git_attr_check *check)
 550{
 551        const char *value = check->value;
 552
 553        return !!ATTR_TRUE(value);
 554}
 555
 556int convert_to_git(const char *path, const char *src, size_t len, struct strbuf *dst)
 557{
 558        struct git_attr_check check[3];
 559        int crlf = CRLF_GUESS;
 560        int ident = 0, ret = 0;
 561        char *filter = NULL;
 562
 563        setup_convert_check(check);
 564        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 565                struct convert_driver *drv;
 566                crlf = git_path_check_crlf(path, check + 0);
 567                ident = git_path_check_ident(path, check + 1);
 568                drv = git_path_check_convert(path, check + 2);
 569                if (drv && drv->clean)
 570                        filter = drv->clean;
 571        }
 572
 573        ret |= apply_filter(path, src, len, dst, filter);
 574        if (ret) {
 575                src = dst->buf;
 576                len = dst->len;
 577        }
 578        ret |= crlf_to_git(path, src, len, dst, crlf);
 579        if (ret) {
 580                src = dst->buf;
 581                len = dst->len;
 582        }
 583        return ret | ident_to_git(path, src, len, dst, ident);
 584}
 585
 586int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 587{
 588        struct git_attr_check check[3];
 589        int crlf = CRLF_GUESS;
 590        int ident = 0, ret = 0;
 591        char *filter = NULL;
 592
 593        setup_convert_check(check);
 594        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 595                struct convert_driver *drv;
 596                crlf = git_path_check_crlf(path, check + 0);
 597                ident = git_path_check_ident(path, check + 1);
 598                drv = git_path_check_convert(path, check + 2);
 599                if (drv && drv->smudge)
 600                        filter = drv->smudge;
 601        }
 602
 603        ret |= ident_to_worktree(path, src, len, dst, ident);
 604        if (ret) {
 605                src = dst->buf;
 606                len = dst->len;
 607        }
 608        ret |= crlf_to_worktree(path, src, len, dst, crlf);
 609        if (ret) {
 610                src = dst->buf;
 611                len = dst->len;
 612        }
 613        return ret | apply_filter(path, src, len, dst, filter);
 614}