Andrew's git / gitweb.git / convert.c
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convert.con commit optimize verify-pack a bit (9909323)
   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        /* NUL, CR, LF and CRLF counts */
  21        unsigned nul, 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                        case 0:
  55                                stats->nul++;
  56                                /* fall through */
  57                        default:
  58                                stats->nonprintable++;
  59                        }
  60                }
  61                else
  62                        stats->printable++;
  63        }
  64}
  65
  66/*
  67 * The same heuristics as diff.c::mmfile_is_binary()
  68 */
  69static int is_binary(unsigned long size, struct text_stat *stats)
  70{
  71
  72        if (stats->nul)
  73                return 1;
  74        if ((stats->printable >> 7) < stats->nonprintable)
  75                return 1;
  76        /*
  77         * Other heuristics? Average line length might be relevant,
  78         * as might LF vs CR vs CRLF counts..
  79         *
  80         * NOTE! It might be normal to have a low ratio of CRLF to LF
  81         * (somebody starts with a LF-only file and edits it with an editor
  82         * that adds CRLF only to lines that are added..). But do  we
  83         * want to support CR-only? Probably not.
  84         */
  85        return 0;
  86}
  87
  88static void check_safe_crlf(const char *path, int action,
  89                            struct text_stat *stats, enum safe_crlf checksafe)
  90{
  91        if (!checksafe)
  92                return;
  93
  94        if (action == CRLF_INPUT || auto_crlf <= 0) {
  95                /*
  96                 * CRLFs would not be restored by checkout:
  97                 * check if we'd remove CRLFs
  98                 */
  99                if (stats->crlf) {
 100                        if (checksafe == SAFE_CRLF_WARN)
 101                                warning("CRLF will be replaced by LF in %s.", path);
 102                        else /* i.e. SAFE_CRLF_FAIL */
 103                                die("CRLF would be replaced by LF in %s.", path);
 104                }
 105        } else if (auto_crlf > 0) {
 106                /*
 107                 * CRLFs would be added by checkout:
 108                 * check if we have "naked" LFs
 109                 */
 110                if (stats->lf != stats->crlf) {
 111                        if (checksafe == SAFE_CRLF_WARN)
 112                                warning("LF will be replaced by CRLF in %s", path);
 113                        else /* i.e. SAFE_CRLF_FAIL */
 114                                die("LF would be replaced by CRLF in %s", path);
 115                }
 116        }
 117}
 118
 119static int crlf_to_git(const char *path, const char *src, size_t len,
 120                       struct strbuf *buf, int action, enum safe_crlf checksafe)
 121{
 122        struct text_stat stats;
 123        char *dst;
 124
 125        if ((action == CRLF_BINARY) || !auto_crlf || !len)
 126                return 0;
 127
 128        gather_stats(src, len, &stats);
 129
 130        if (action == CRLF_GUESS) {
 131                /*
 132                 * We're currently not going to even try to convert stuff
 133                 * that has bare CR characters. Does anybody do that crazy
 134                 * stuff?
 135                 */
 136                if (stats.cr != stats.crlf)
 137                        return 0;
 138
 139                /*
 140                 * And add some heuristics for binary vs text, of course...
 141                 */
 142                if (is_binary(len, &stats))
 143                        return 0;
 144        }
 145
 146        check_safe_crlf(path, action, &stats, checksafe);
 147
 148        /* Optimization: No CR? Nothing to convert, regardless. */
 149        if (!stats.cr)
 150                return 0;
 151
 152        /* only grow if not in place */
 153        if (strbuf_avail(buf) + buf->len < len)
 154                strbuf_grow(buf, len - buf->len);
 155        dst = buf->buf;
 156        if (action == CRLF_GUESS) {
 157                /*
 158                 * If we guessed, we already know we rejected a file with
 159                 * lone CR, and we can strip a CR without looking at what
 160                 * follow it.
 161                 */
 162                do {
 163                        unsigned char c = *src++;
 164                        if (c != '\r')
 165                                *dst++ = c;
 166                } while (--len);
 167        } else {
 168                do {
 169                        unsigned char c = *src++;
 170                        if (! (c == '\r' && (1 < len && *src == '\n')))
 171                                *dst++ = c;
 172                } while (--len);
 173        }
 174        strbuf_setlen(buf, dst - buf->buf);
 175        return 1;
 176}
 177
 178static int crlf_to_worktree(const char *path, const char *src, size_t len,
 179                            struct strbuf *buf, int action)
 180{
 181        char *to_free = NULL;
 182        struct text_stat stats;
 183
 184        if ((action == CRLF_BINARY) || (action == CRLF_INPUT) ||
 185            auto_crlf <= 0)
 186                return 0;
 187
 188        if (!len)
 189                return 0;
 190
 191        gather_stats(src, len, &stats);
 192
 193        /* No LF? Nothing to convert, regardless. */
 194        if (!stats.lf)
 195                return 0;
 196
 197        /* Was it already in CRLF format? */
 198        if (stats.lf == stats.crlf)
 199                return 0;
 200
 201        if (action == CRLF_GUESS) {
 202                /* If we have any bare CR characters, we're not going to touch it */
 203                if (stats.cr != stats.crlf)
 204                        return 0;
 205
 206                if (is_binary(len, &stats))
 207                        return 0;
 208        }
 209
 210        /* are we "faking" in place editing ? */
 211        if (src == buf->buf)
 212                to_free = strbuf_detach(buf, NULL);
 213
 214        strbuf_grow(buf, len + stats.lf - stats.crlf);
 215        for (;;) {
 216                const char *nl = memchr(src, '\n', len);
 217                if (!nl)
 218                        break;
 219                if (nl > src && nl[-1] == '\r') {
 220                        strbuf_add(buf, src, nl + 1 - src);
 221                } else {
 222                        strbuf_add(buf, src, nl - src);
 223                        strbuf_addstr(buf, "\r\n");
 224                }
 225                len -= nl + 1 - src;
 226                src  = nl + 1;
 227        }
 228        strbuf_add(buf, src, len);
 229
 230        free(to_free);
 231        return 1;
 232}
 233
 234struct filter_params {
 235        const char *src;
 236        unsigned long size;
 237        const char *cmd;
 238};
 239
 240static int filter_buffer(int fd, void *data)
 241{
 242        /*
 243         * Spawn cmd and feed the buffer contents through its stdin.
 244         */
 245        struct child_process child_process;
 246        struct filter_params *params = (struct filter_params *)data;
 247        int write_err, status;
 248        const char *argv[] = { "sh", "-c", params->cmd, NULL };
 249
 250        memset(&child_process, 0, sizeof(child_process));
 251        child_process.argv = argv;
 252        child_process.in = -1;
 253        child_process.out = fd;
 254
 255        if (start_command(&child_process))
 256                return error("cannot fork to run external filter %s", params->cmd);
 257
 258        write_err = (write_in_full(child_process.in, params->src, params->size) < 0);
 259        if (close(child_process.in))
 260                write_err = 1;
 261        if (write_err)
 262                error("cannot feed the input to external filter %s", params->cmd);
 263
 264        status = finish_command(&child_process);
 265        if (status)
 266                error("external filter %s failed %d", params->cmd, -status);
 267        return (write_err || status);
 268}
 269
 270static int apply_filter(const char *path, const char *src, size_t len,
 271                        struct strbuf *dst, const char *cmd)
 272{
 273        /*
 274         * Create a pipeline to have the command filter the buffer's
 275         * contents.
 276         *
 277         * (child --> cmd) --> us
 278         */
 279        int ret = 1;
 280        struct strbuf nbuf;
 281        struct async async;
 282        struct filter_params params;
 283
 284        if (!cmd)
 285                return 0;
 286
 287        memset(&async, 0, sizeof(async));
 288        async.proc = filter_buffer;
 289        async.data = &params;
 290        params.src = src;
 291        params.size = len;
 292        params.cmd = cmd;
 293
 294        fflush(NULL);
 295        if (start_async(&async))
 296                return 0;       /* error was already reported */
 297
 298        strbuf_init(&nbuf, 0);
 299        if (strbuf_read(&nbuf, async.out, len) < 0) {
 300                error("read from external filter %s failed", cmd);
 301                ret = 0;
 302        }
 303        if (close(async.out)) {
 304                error("read from external filter %s failed", cmd);
 305                ret = 0;
 306        }
 307        if (finish_async(&async)) {
 308                error("external filter %s failed", cmd);
 309                ret = 0;
 310        }
 311
 312        if (ret) {
 313                strbuf_swap(dst, &nbuf);
 314        }
 315        strbuf_release(&nbuf);
 316        return ret;
 317}
 318
 319static struct convert_driver {
 320        const char *name;
 321        struct convert_driver *next;
 322        char *smudge;
 323        char *clean;
 324} *user_convert, **user_convert_tail;
 325
 326static int read_convert_config(const char *var, const char *value, void *cb)
 327{
 328        const char *ep, *name;
 329        int namelen;
 330        struct convert_driver *drv;
 331
 332        /*
 333         * External conversion drivers are configured using
 334         * "filter.<name>.variable".
 335         */
 336        if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
 337                return 0;
 338        name = var + 7;
 339        namelen = ep - name;
 340        for (drv = user_convert; drv; drv = drv->next)
 341                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 342                        break;
 343        if (!drv) {
 344                drv = xcalloc(1, sizeof(struct convert_driver));
 345                drv->name = xmemdupz(name, namelen);
 346                *user_convert_tail = drv;
 347                user_convert_tail = &(drv->next);
 348        }
 349
 350        ep++;
 351
 352        /*
 353         * filter.<name>.smudge and filter.<name>.clean specifies
 354         * the command line:
 355         *
 356         *      command-line
 357         *
 358         * The command-line will not be interpolated in any way.
 359         */
 360
 361        if (!strcmp("smudge", ep)) {
 362                if (!value)
 363                        return config_error_nonbool(var);
 364                drv->smudge = strdup(value);
 365                return 0;
 366        }
 367
 368        if (!strcmp("clean", ep)) {
 369                if (!value)
 370                        return config_error_nonbool(var);
 371                drv->clean = strdup(value);
 372                return 0;
 373        }
 374        return 0;
 375}
 376
 377static void setup_convert_check(struct git_attr_check *check)
 378{
 379        static struct git_attr *attr_crlf;
 380        static struct git_attr *attr_ident;
 381        static struct git_attr *attr_filter;
 382
 383        if (!attr_crlf) {
 384                attr_crlf = git_attr("crlf", 4);
 385                attr_ident = git_attr("ident", 5);
 386                attr_filter = git_attr("filter", 6);
 387                user_convert_tail = &user_convert;
 388                git_config(read_convert_config, NULL);
 389        }
 390        check[0].attr = attr_crlf;
 391        check[1].attr = attr_ident;
 392        check[2].attr = attr_filter;
 393}
 394
 395static int count_ident(const char *cp, unsigned long size)
 396{
 397        /*
 398         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 399         */
 400        int cnt = 0;
 401        char ch;
 402
 403        while (size) {
 404                ch = *cp++;
 405                size--;
 406                if (ch != '$')
 407                        continue;
 408                if (size < 3)
 409                        break;
 410                if (memcmp("Id", cp, 2))
 411                        continue;
 412                ch = cp[2];
 413                cp += 3;
 414                size -= 3;
 415                if (ch == '$')
 416                        cnt++; /* $Id$ */
 417                if (ch != ':')
 418                        continue;
 419
 420                /*
 421                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 422                 */
 423                while (size) {
 424                        ch = *cp++;
 425                        size--;
 426                        if (ch == '$') {
 427                                cnt++;
 428                                break;
 429                        }
 430                }
 431        }
 432        return cnt;
 433}
 434
 435static int ident_to_git(const char *path, const char *src, size_t len,
 436                        struct strbuf *buf, int ident)
 437{
 438        char *dst, *dollar;
 439
 440        if (!ident || !count_ident(src, len))
 441                return 0;
 442
 443        /* only grow if not in place */
 444        if (strbuf_avail(buf) + buf->len < len)
 445                strbuf_grow(buf, len - buf->len);
 446        dst = buf->buf;
 447        for (;;) {
 448                dollar = memchr(src, '$', len);
 449                if (!dollar)
 450                        break;
 451                memcpy(dst, src, dollar + 1 - src);
 452                dst += dollar + 1 - src;
 453                len -= dollar + 1 - src;
 454                src  = dollar + 1;
 455
 456                if (len > 3 && !memcmp(src, "Id:", 3)) {
 457                        dollar = memchr(src + 3, '$', len - 3);
 458                        if (!dollar)
 459                                break;
 460                        memcpy(dst, "Id$", 3);
 461                        dst += 3;
 462                        len -= dollar + 1 - src;
 463                        src  = dollar + 1;
 464                }
 465        }
 466        memcpy(dst, src, len);
 467        strbuf_setlen(buf, dst + len - buf->buf);
 468        return 1;
 469}
 470
 471static int ident_to_worktree(const char *path, const char *src, size_t len,
 472                             struct strbuf *buf, int ident)
 473{
 474        unsigned char sha1[20];
 475        char *to_free = NULL, *dollar;
 476        int cnt;
 477
 478        if (!ident)
 479                return 0;
 480
 481        cnt = count_ident(src, len);
 482        if (!cnt)
 483                return 0;
 484
 485        /* are we "faking" in place editing ? */
 486        if (src == buf->buf)
 487                to_free = strbuf_detach(buf, NULL);
 488        hash_sha1_file(src, len, "blob", sha1);
 489
 490        strbuf_grow(buf, len + cnt * 43);
 491        for (;;) {
 492                /* step 1: run to the next '$' */
 493                dollar = memchr(src, '$', len);
 494                if (!dollar)
 495                        break;
 496                strbuf_add(buf, src, dollar + 1 - src);
 497                len -= dollar + 1 - src;
 498                src  = dollar + 1;
 499
 500                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 501                if (len < 3 || memcmp("Id", src, 2))
 502                        continue;
 503
 504                /* step 3: skip over Id$ or Id:xxxxx$ */
 505                if (src[2] == '$') {
 506                        src += 3;
 507                        len -= 3;
 508                } else if (src[2] == ':') {
 509                        /*
 510                         * It's possible that an expanded Id has crept its way into the
 511                         * repository, we cope with that by stripping the expansion out
 512                         */
 513                        dollar = memchr(src + 3, '$', len - 3);
 514                        if (!dollar) {
 515                                /* incomplete keyword, no more '$', so just quit the loop */
 516                                break;
 517                        }
 518
 519                        len -= dollar + 1 - src;
 520                        src  = dollar + 1;
 521                } else {
 522                        /* it wasn't a "Id$" or "Id:xxxx$" */
 523                        continue;
 524                }
 525
 526                /* step 4: substitute */
 527                strbuf_addstr(buf, "Id: ");
 528                strbuf_add(buf, sha1_to_hex(sha1), 40);
 529                strbuf_addstr(buf, " $");
 530        }
 531        strbuf_add(buf, src, len);
 532
 533        free(to_free);
 534        return 1;
 535}
 536
 537static int git_path_check_crlf(const char *path, struct git_attr_check *check)
 538{
 539        const char *value = check->value;
 540
 541        if (ATTR_TRUE(value))
 542                return CRLF_TEXT;
 543        else if (ATTR_FALSE(value))
 544                return CRLF_BINARY;
 545        else if (ATTR_UNSET(value))
 546                ;
 547        else if (!strcmp(value, "input"))
 548                return CRLF_INPUT;
 549        return CRLF_GUESS;
 550}
 551
 552static struct convert_driver *git_path_check_convert(const char *path,
 553                                             struct git_attr_check *check)
 554{
 555        const char *value = check->value;
 556        struct convert_driver *drv;
 557
 558        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 559                return NULL;
 560        for (drv = user_convert; drv; drv = drv->next)
 561                if (!strcmp(value, drv->name))
 562                        return drv;
 563        return NULL;
 564}
 565
 566static int git_path_check_ident(const char *path, struct git_attr_check *check)
 567{
 568        const char *value = check->value;
 569
 570        return !!ATTR_TRUE(value);
 571}
 572
 573int convert_to_git(const char *path, const char *src, size_t len,
 574                   struct strbuf *dst, enum safe_crlf checksafe)
 575{
 576        struct git_attr_check check[3];
 577        int crlf = CRLF_GUESS;
 578        int ident = 0, ret = 0;
 579        char *filter = NULL;
 580
 581        setup_convert_check(check);
 582        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 583                struct convert_driver *drv;
 584                crlf = git_path_check_crlf(path, check + 0);
 585                ident = git_path_check_ident(path, check + 1);
 586                drv = git_path_check_convert(path, check + 2);
 587                if (drv && drv->clean)
 588                        filter = drv->clean;
 589        }
 590
 591        ret |= apply_filter(path, src, len, dst, filter);
 592        if (ret) {
 593                src = dst->buf;
 594                len = dst->len;
 595        }
 596        ret |= crlf_to_git(path, src, len, dst, crlf, checksafe);
 597        if (ret) {
 598                src = dst->buf;
 599                len = dst->len;
 600        }
 601        return ret | ident_to_git(path, src, len, dst, ident);
 602}
 603
 604int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
 605{
 606        struct git_attr_check check[3];
 607        int crlf = CRLF_GUESS;
 608        int ident = 0, ret = 0;
 609        char *filter = NULL;
 610
 611        setup_convert_check(check);
 612        if (!git_checkattr(path, ARRAY_SIZE(check), check)) {
 613                struct convert_driver *drv;
 614                crlf = git_path_check_crlf(path, check + 0);
 615                ident = git_path_check_ident(path, check + 1);
 616                drv = git_path_check_convert(path, check + 2);
 617                if (drv && drv->smudge)
 618                        filter = drv->smudge;
 619        }
 620
 621        ret |= ident_to_worktree(path, src, len, dst, ident);
 622        if (ret) {
 623                src = dst->buf;
 624                len = dst->len;
 625        }
 626        ret |= crlf_to_worktree(path, src, len, dst, crlf);
 627        if (ret) {
 628                src = dst->buf;
 629                len = dst->len;
 630        }
 631        return ret | apply_filter(path, src, len, dst, filter);
 632}