convert.con commit Merge branch 'jc/skip-test-in-the-middle' (9aa5559)
   1#include "cache.h"
   2#include "attr.h"
   3#include "run-command.h"
   4#include "quote.h"
   5#include "sigchain.h"
   6#include "pkt-line.h"
   7#include "sub-process.h"
   8
   9/*
  10 * convert.c - convert a file when checking it out and checking it in.
  11 *
  12 * This should use the pathname to decide on whether it wants to do some
  13 * more interesting conversions (automatic gzip/unzip, general format
  14 * conversions etc etc), but by default it just does automatic CRLF<->LF
  15 * translation when the "text" attribute or "auto_crlf" option is set.
  16 */
  17
  18/* Stat bits: When BIN is set, the txt bits are unset */
  19#define CONVERT_STAT_BITS_TXT_LF    0x1
  20#define CONVERT_STAT_BITS_TXT_CRLF  0x2
  21#define CONVERT_STAT_BITS_BIN       0x4
  22
  23enum crlf_action {
  24        CRLF_UNDEFINED,
  25        CRLF_BINARY,
  26        CRLF_TEXT,
  27        CRLF_TEXT_INPUT,
  28        CRLF_TEXT_CRLF,
  29        CRLF_AUTO,
  30        CRLF_AUTO_INPUT,
  31        CRLF_AUTO_CRLF
  32};
  33
  34struct text_stat {
  35        /* NUL, CR, LF and CRLF counts */
  36        unsigned nul, lonecr, lonelf, crlf;
  37
  38        /* These are just approximations! */
  39        unsigned printable, nonprintable;
  40};
  41
  42static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  43{
  44        unsigned long i;
  45
  46        memset(stats, 0, sizeof(*stats));
  47
  48        for (i = 0; i < size; i++) {
  49                unsigned char c = buf[i];
  50                if (c == '\r') {
  51                        if (i+1 < size && buf[i+1] == '\n') {
  52                                stats->crlf++;
  53                                i++;
  54                        } else
  55                                stats->lonecr++;
  56                        continue;
  57                }
  58                if (c == '\n') {
  59                        stats->lonelf++;
  60                        continue;
  61                }
  62                if (c == 127)
  63                        /* DEL */
  64                        stats->nonprintable++;
  65                else if (c < 32) {
  66                        switch (c) {
  67                                /* BS, HT, ESC and FF */
  68                        case '\b': case '\t': case '\033': case '\014':
  69                                stats->printable++;
  70                                break;
  71                        case 0:
  72                                stats->nul++;
  73                                /* fall through */
  74                        default:
  75                                stats->nonprintable++;
  76                        }
  77                }
  78                else
  79                        stats->printable++;
  80        }
  81
  82        /* If file ends with EOF then don't count this EOF as non-printable. */
  83        if (size >= 1 && buf[size-1] == '\032')
  84                stats->nonprintable--;
  85}
  86
  87/*
  88 * The same heuristics as diff.c::mmfile_is_binary()
  89 * We treat files with bare CR as binary
  90 */
  91static int convert_is_binary(unsigned long size, const struct text_stat *stats)
  92{
  93        if (stats->lonecr)
  94                return 1;
  95        if (stats->nul)
  96                return 1;
  97        if ((stats->printable >> 7) < stats->nonprintable)
  98                return 1;
  99        return 0;
 100}
 101
 102static unsigned int gather_convert_stats(const char *data, unsigned long size)
 103{
 104        struct text_stat stats;
 105        int ret = 0;
 106        if (!data || !size)
 107                return 0;
 108        gather_stats(data, size, &stats);
 109        if (convert_is_binary(size, &stats))
 110                ret |= CONVERT_STAT_BITS_BIN;
 111        if (stats.crlf)
 112                ret |= CONVERT_STAT_BITS_TXT_CRLF;
 113        if (stats.lonelf)
 114                ret |=  CONVERT_STAT_BITS_TXT_LF;
 115
 116        return ret;
 117}
 118
 119static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
 120{
 121        unsigned int convert_stats = gather_convert_stats(data, size);
 122
 123        if (convert_stats & CONVERT_STAT_BITS_BIN)
 124                return "-text";
 125        switch (convert_stats) {
 126        case CONVERT_STAT_BITS_TXT_LF:
 127                return "lf";
 128        case CONVERT_STAT_BITS_TXT_CRLF:
 129                return "crlf";
 130        case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
 131                return "mixed";
 132        default:
 133                return "none";
 134        }
 135}
 136
 137const char *get_cached_convert_stats_ascii(const char *path)
 138{
 139        const char *ret;
 140        unsigned long sz;
 141        void *data = read_blob_data_from_cache(path, &sz);
 142        ret = gather_convert_stats_ascii(data, sz);
 143        free(data);
 144        return ret;
 145}
 146
 147const char *get_wt_convert_stats_ascii(const char *path)
 148{
 149        const char *ret = "";
 150        struct strbuf sb = STRBUF_INIT;
 151        if (strbuf_read_file(&sb, path, 0) >= 0)
 152                ret = gather_convert_stats_ascii(sb.buf, sb.len);
 153        strbuf_release(&sb);
 154        return ret;
 155}
 156
 157static int text_eol_is_crlf(void)
 158{
 159        if (auto_crlf == AUTO_CRLF_TRUE)
 160                return 1;
 161        else if (auto_crlf == AUTO_CRLF_INPUT)
 162                return 0;
 163        if (core_eol == EOL_CRLF)
 164                return 1;
 165        if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
 166                return 1;
 167        return 0;
 168}
 169
 170static enum eol output_eol(enum crlf_action crlf_action)
 171{
 172        switch (crlf_action) {
 173        case CRLF_BINARY:
 174                return EOL_UNSET;
 175        case CRLF_TEXT_CRLF:
 176                return EOL_CRLF;
 177        case CRLF_TEXT_INPUT:
 178                return EOL_LF;
 179        case CRLF_UNDEFINED:
 180        case CRLF_AUTO_CRLF:
 181                return EOL_CRLF;
 182        case CRLF_AUTO_INPUT:
 183                return EOL_LF;
 184        case CRLF_TEXT:
 185        case CRLF_AUTO:
 186                /* fall through */
 187                return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
 188        }
 189        warning("Illegal crlf_action %d\n", (int)crlf_action);
 190        return core_eol;
 191}
 192
 193static void check_safe_crlf(const char *path, enum crlf_action crlf_action,
 194                            struct text_stat *old_stats, struct text_stat *new_stats,
 195                            enum safe_crlf checksafe)
 196{
 197        if (old_stats->crlf && !new_stats->crlf ) {
 198                /*
 199                 * CRLFs would not be restored by checkout
 200                 */
 201                if (checksafe == SAFE_CRLF_WARN)
 202                        warning(_("CRLF will be replaced by LF in %s.\n"
 203                                  "The file will have its original line"
 204                                  " endings in your working directory."), path);
 205                else /* i.e. SAFE_CRLF_FAIL */
 206                        die(_("CRLF would be replaced by LF in %s."), path);
 207        } else if (old_stats->lonelf && !new_stats->lonelf ) {
 208                /*
 209                 * CRLFs would be added by checkout
 210                 */
 211                if (checksafe == SAFE_CRLF_WARN)
 212                        warning(_("LF will be replaced by CRLF in %s.\n"
 213                                  "The file will have its original line"
 214                                  " endings in your working directory."), path);
 215                else /* i.e. SAFE_CRLF_FAIL */
 216                        die(_("LF would be replaced by CRLF in %s"), path);
 217        }
 218}
 219
 220static int has_cr_in_index(const char *path)
 221{
 222        unsigned long sz;
 223        void *data;
 224        int has_cr;
 225
 226        data = read_blob_data_from_cache(path, &sz);
 227        if (!data)
 228                return 0;
 229        has_cr = memchr(data, '\r', sz) != NULL;
 230        free(data);
 231        return has_cr;
 232}
 233
 234static int will_convert_lf_to_crlf(size_t len, struct text_stat *stats,
 235                                   enum crlf_action crlf_action)
 236{
 237        if (output_eol(crlf_action) != EOL_CRLF)
 238                return 0;
 239        /* No "naked" LF? Nothing to convert, regardless. */
 240        if (!stats->lonelf)
 241                return 0;
 242
 243        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 244                /* If we have any CR or CRLF line endings, we do not touch it */
 245                /* This is the new safer autocrlf-handling */
 246                if (stats->lonecr || stats->crlf)
 247                        return 0;
 248
 249                if (convert_is_binary(len, stats))
 250                        return 0;
 251        }
 252        return 1;
 253
 254}
 255
 256static int crlf_to_git(const char *path, const char *src, size_t len,
 257                       struct strbuf *buf,
 258                       enum crlf_action crlf_action, enum safe_crlf checksafe)
 259{
 260        struct text_stat stats;
 261        char *dst;
 262        int convert_crlf_into_lf;
 263
 264        if (crlf_action == CRLF_BINARY ||
 265            (src && !len))
 266                return 0;
 267
 268        /*
 269         * If we are doing a dry-run and have no source buffer, there is
 270         * nothing to analyze; we must assume we would convert.
 271         */
 272        if (!buf && !src)
 273                return 1;
 274
 275        gather_stats(src, len, &stats);
 276        /* Optimization: No CRLF? Nothing to convert, regardless. */
 277        convert_crlf_into_lf = !!stats.crlf;
 278
 279        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 280                if (convert_is_binary(len, &stats))
 281                        return 0;
 282                /*
 283                 * If the file in the index has any CR in it, do not
 284                 * convert.  This is the new safer autocrlf handling,
 285                 * unless we want to renormalize in a merge or
 286                 * cherry-pick.
 287                 */
 288                if ((checksafe != SAFE_CRLF_RENORMALIZE) && has_cr_in_index(path))
 289                        convert_crlf_into_lf = 0;
 290        }
 291        if ((checksafe == SAFE_CRLF_WARN ||
 292            (checksafe == SAFE_CRLF_FAIL)) && len) {
 293                struct text_stat new_stats;
 294                memcpy(&new_stats, &stats, sizeof(new_stats));
 295                /* simulate "git add" */
 296                if (convert_crlf_into_lf) {
 297                        new_stats.lonelf += new_stats.crlf;
 298                        new_stats.crlf = 0;
 299                }
 300                /* simulate "git checkout" */
 301                if (will_convert_lf_to_crlf(len, &new_stats, crlf_action)) {
 302                        new_stats.crlf += new_stats.lonelf;
 303                        new_stats.lonelf = 0;
 304                }
 305                check_safe_crlf(path, crlf_action, &stats, &new_stats, checksafe);
 306        }
 307        if (!convert_crlf_into_lf)
 308                return 0;
 309
 310        /*
 311         * At this point all of our source analysis is done, and we are sure we
 312         * would convert. If we are in dry-run mode, we can give an answer.
 313         */
 314        if (!buf)
 315                return 1;
 316
 317        /* only grow if not in place */
 318        if (strbuf_avail(buf) + buf->len < len)
 319                strbuf_grow(buf, len - buf->len);
 320        dst = buf->buf;
 321        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 322                /*
 323                 * If we guessed, we already know we rejected a file with
 324                 * lone CR, and we can strip a CR without looking at what
 325                 * follow it.
 326                 */
 327                do {
 328                        unsigned char c = *src++;
 329                        if (c != '\r')
 330                                *dst++ = c;
 331                } while (--len);
 332        } else {
 333                do {
 334                        unsigned char c = *src++;
 335                        if (! (c == '\r' && (1 < len && *src == '\n')))
 336                                *dst++ = c;
 337                } while (--len);
 338        }
 339        strbuf_setlen(buf, dst - buf->buf);
 340        return 1;
 341}
 342
 343static int crlf_to_worktree(const char *path, const char *src, size_t len,
 344                            struct strbuf *buf, enum crlf_action crlf_action)
 345{
 346        char *to_free = NULL;
 347        struct text_stat stats;
 348
 349        if (!len || output_eol(crlf_action) != EOL_CRLF)
 350                return 0;
 351
 352        gather_stats(src, len, &stats);
 353        if (!will_convert_lf_to_crlf(len, &stats, crlf_action))
 354                return 0;
 355
 356        /* are we "faking" in place editing ? */
 357        if (src == buf->buf)
 358                to_free = strbuf_detach(buf, NULL);
 359
 360        strbuf_grow(buf, len + stats.lonelf);
 361        for (;;) {
 362                const char *nl = memchr(src, '\n', len);
 363                if (!nl)
 364                        break;
 365                if (nl > src && nl[-1] == '\r') {
 366                        strbuf_add(buf, src, nl + 1 - src);
 367                } else {
 368                        strbuf_add(buf, src, nl - src);
 369                        strbuf_addstr(buf, "\r\n");
 370                }
 371                len -= nl + 1 - src;
 372                src  = nl + 1;
 373        }
 374        strbuf_add(buf, src, len);
 375
 376        free(to_free);
 377        return 1;
 378}
 379
 380struct filter_params {
 381        const char *src;
 382        unsigned long size;
 383        int fd;
 384        const char *cmd;
 385        const char *path;
 386};
 387
 388static int filter_buffer_or_fd(int in, int out, void *data)
 389{
 390        /*
 391         * Spawn cmd and feed the buffer contents through its stdin.
 392         */
 393        struct child_process child_process = CHILD_PROCESS_INIT;
 394        struct filter_params *params = (struct filter_params *)data;
 395        int write_err, status;
 396        const char *argv[] = { NULL, NULL };
 397
 398        /* apply % substitution to cmd */
 399        struct strbuf cmd = STRBUF_INIT;
 400        struct strbuf path = STRBUF_INIT;
 401        struct strbuf_expand_dict_entry dict[] = {
 402                { "f", NULL, },
 403                { NULL, NULL, },
 404        };
 405
 406        /* quote the path to preserve spaces, etc. */
 407        sq_quote_buf(&path, params->path);
 408        dict[0].value = path.buf;
 409
 410        /* expand all %f with the quoted path */
 411        strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 412        strbuf_release(&path);
 413
 414        argv[0] = cmd.buf;
 415
 416        child_process.argv = argv;
 417        child_process.use_shell = 1;
 418        child_process.in = -1;
 419        child_process.out = out;
 420
 421        if (start_command(&child_process))
 422                return error("cannot fork to run external filter '%s'", params->cmd);
 423
 424        sigchain_push(SIGPIPE, SIG_IGN);
 425
 426        if (params->src) {
 427                write_err = (write_in_full(child_process.in,
 428                                           params->src, params->size) < 0);
 429                if (errno == EPIPE)
 430                        write_err = 0;
 431        } else {
 432                write_err = copy_fd(params->fd, child_process.in);
 433                if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
 434                        write_err = 0;
 435        }
 436
 437        if (close(child_process.in))
 438                write_err = 1;
 439        if (write_err)
 440                error("cannot feed the input to external filter '%s'", params->cmd);
 441
 442        sigchain_pop(SIGPIPE);
 443
 444        status = finish_command(&child_process);
 445        if (status)
 446                error("external filter '%s' failed %d", params->cmd, status);
 447
 448        strbuf_release(&cmd);
 449        return (write_err || status);
 450}
 451
 452static int apply_single_file_filter(const char *path, const char *src, size_t len, int fd,
 453                        struct strbuf *dst, const char *cmd)
 454{
 455        /*
 456         * Create a pipeline to have the command filter the buffer's
 457         * contents.
 458         *
 459         * (child --> cmd) --> us
 460         */
 461        int err = 0;
 462        struct strbuf nbuf = STRBUF_INIT;
 463        struct async async;
 464        struct filter_params params;
 465
 466        memset(&async, 0, sizeof(async));
 467        async.proc = filter_buffer_or_fd;
 468        async.data = &params;
 469        async.out = -1;
 470        params.src = src;
 471        params.size = len;
 472        params.fd = fd;
 473        params.cmd = cmd;
 474        params.path = path;
 475
 476        fflush(NULL);
 477        if (start_async(&async))
 478                return 0;       /* error was already reported */
 479
 480        if (strbuf_read(&nbuf, async.out, len) < 0) {
 481                err = error("read from external filter '%s' failed", cmd);
 482        }
 483        if (close(async.out)) {
 484                err = error("read from external filter '%s' failed", cmd);
 485        }
 486        if (finish_async(&async)) {
 487                err = error("external filter '%s' failed", cmd);
 488        }
 489
 490        if (!err) {
 491                strbuf_swap(dst, &nbuf);
 492        }
 493        strbuf_release(&nbuf);
 494        return !err;
 495}
 496
 497#define CAP_CLEAN    (1u<<0)
 498#define CAP_SMUDGE   (1u<<1)
 499
 500struct cmd2process {
 501        struct subprocess_entry subprocess; /* must be the first member! */
 502        unsigned int supported_capabilities;
 503};
 504
 505static int subprocess_map_initialized;
 506static struct hashmap subprocess_map;
 507
 508static int start_multi_file_filter_fn(struct subprocess_entry *subprocess)
 509{
 510        int err;
 511        struct cmd2process *entry = (struct cmd2process *)subprocess;
 512        struct string_list cap_list = STRING_LIST_INIT_NODUP;
 513        char *cap_buf;
 514        const char *cap_name;
 515        struct child_process *process = &subprocess->process;
 516        const char *cmd = subprocess->cmd;
 517
 518        sigchain_push(SIGPIPE, SIG_IGN);
 519
 520        err = packet_writel(process->in, "git-filter-client", "version=2", NULL);
 521        if (err)
 522                goto done;
 523
 524        err = strcmp(packet_read_line(process->out, NULL), "git-filter-server");
 525        if (err) {
 526                error("external filter '%s' does not support filter protocol version 2", cmd);
 527                goto done;
 528        }
 529        err = strcmp(packet_read_line(process->out, NULL), "version=2");
 530        if (err)
 531                goto done;
 532        err = packet_read_line(process->out, NULL) != NULL;
 533        if (err)
 534                goto done;
 535
 536        err = packet_writel(process->in, "capability=clean", "capability=smudge", NULL);
 537
 538        for (;;) {
 539                cap_buf = packet_read_line(process->out, NULL);
 540                if (!cap_buf)
 541                        break;
 542                string_list_split_in_place(&cap_list, cap_buf, '=', 1);
 543
 544                if (cap_list.nr != 2 || strcmp(cap_list.items[0].string, "capability"))
 545                        continue;
 546
 547                cap_name = cap_list.items[1].string;
 548                if (!strcmp(cap_name, "clean")) {
 549                        entry->supported_capabilities |= CAP_CLEAN;
 550                } else if (!strcmp(cap_name, "smudge")) {
 551                        entry->supported_capabilities |= CAP_SMUDGE;
 552                } else {
 553                        warning(
 554                                "external filter '%s' requested unsupported filter capability '%s'",
 555                                cmd, cap_name
 556                        );
 557                }
 558
 559                string_list_clear(&cap_list, 0);
 560        }
 561
 562done:
 563        sigchain_pop(SIGPIPE);
 564
 565        return err;
 566}
 567
 568static int apply_multi_file_filter(const char *path, const char *src, size_t len,
 569                                   int fd, struct strbuf *dst, const char *cmd,
 570                                   const unsigned int wanted_capability)
 571{
 572        int err;
 573        struct cmd2process *entry;
 574        struct child_process *process;
 575        struct strbuf nbuf = STRBUF_INIT;
 576        struct strbuf filter_status = STRBUF_INIT;
 577        const char *filter_type;
 578
 579        if (!subprocess_map_initialized) {
 580                subprocess_map_initialized = 1;
 581                hashmap_init(&subprocess_map, (hashmap_cmp_fn) cmd2process_cmp, 0);
 582                entry = NULL;
 583        } else {
 584                entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
 585        }
 586
 587        fflush(NULL);
 588
 589        if (!entry) {
 590                entry = xmalloc(sizeof(*entry));
 591                entry->supported_capabilities = 0;
 592
 593                if (subprocess_start(&subprocess_map, &entry->subprocess, cmd, start_multi_file_filter_fn)) {
 594                        free(entry);
 595                        return 0;
 596                }
 597        }
 598        process = &entry->subprocess.process;
 599
 600        if (!(wanted_capability & entry->supported_capabilities))
 601                return 0;
 602
 603        if (CAP_CLEAN & wanted_capability)
 604                filter_type = "clean";
 605        else if (CAP_SMUDGE & wanted_capability)
 606                filter_type = "smudge";
 607        else
 608                die("unexpected filter type");
 609
 610        sigchain_push(SIGPIPE, SIG_IGN);
 611
 612        assert(strlen(filter_type) < LARGE_PACKET_DATA_MAX - strlen("command=\n"));
 613        err = packet_write_fmt_gently(process->in, "command=%s\n", filter_type);
 614        if (err)
 615                goto done;
 616
 617        err = strlen(path) > LARGE_PACKET_DATA_MAX - strlen("pathname=\n");
 618        if (err) {
 619                error("path name too long for external filter");
 620                goto done;
 621        }
 622
 623        err = packet_write_fmt_gently(process->in, "pathname=%s\n", path);
 624        if (err)
 625                goto done;
 626
 627        err = packet_flush_gently(process->in);
 628        if (err)
 629                goto done;
 630
 631        if (fd >= 0)
 632                err = write_packetized_from_fd(fd, process->in);
 633        else
 634                err = write_packetized_from_buf(src, len, process->in);
 635        if (err)
 636                goto done;
 637
 638        err = subprocess_read_status(process->out, &filter_status);
 639        if (err)
 640                goto done;
 641
 642        err = strcmp(filter_status.buf, "success");
 643        if (err)
 644                goto done;
 645
 646        err = read_packetized_to_strbuf(process->out, &nbuf) < 0;
 647        if (err)
 648                goto done;
 649
 650        err = subprocess_read_status(process->out, &filter_status);
 651        if (err)
 652                goto done;
 653
 654        err = strcmp(filter_status.buf, "success");
 655
 656done:
 657        sigchain_pop(SIGPIPE);
 658
 659        if (err) {
 660                if (!strcmp(filter_status.buf, "error")) {
 661                        /* The filter signaled a problem with the file. */
 662                } else if (!strcmp(filter_status.buf, "abort")) {
 663                        /*
 664                         * The filter signaled a permanent problem. Don't try to filter
 665                         * files with the same command for the lifetime of the current
 666                         * Git process.
 667                         */
 668                         entry->supported_capabilities &= ~wanted_capability;
 669                } else {
 670                        /*
 671                         * Something went wrong with the protocol filter.
 672                         * Force shutdown and restart if another blob requires filtering.
 673                         */
 674                        error("external filter '%s' failed", cmd);
 675                        subprocess_stop(&subprocess_map, &entry->subprocess);
 676                        free(entry);
 677                }
 678        } else {
 679                strbuf_swap(dst, &nbuf);
 680        }
 681        strbuf_release(&nbuf);
 682        return !err;
 683}
 684
 685static struct convert_driver {
 686        const char *name;
 687        struct convert_driver *next;
 688        const char *smudge;
 689        const char *clean;
 690        const char *process;
 691        int required;
 692} *user_convert, **user_convert_tail;
 693
 694static int apply_filter(const char *path, const char *src, size_t len,
 695                        int fd, struct strbuf *dst, struct convert_driver *drv,
 696                        const unsigned int wanted_capability)
 697{
 698        const char *cmd = NULL;
 699
 700        if (!drv)
 701                return 0;
 702
 703        if (!dst)
 704                return 1;
 705
 706        if ((CAP_CLEAN & wanted_capability) && !drv->process && drv->clean)
 707                cmd = drv->clean;
 708        else if ((CAP_SMUDGE & wanted_capability) && !drv->process && drv->smudge)
 709                cmd = drv->smudge;
 710
 711        if (cmd && *cmd)
 712                return apply_single_file_filter(path, src, len, fd, dst, cmd);
 713        else if (drv->process && *drv->process)
 714                return apply_multi_file_filter(path, src, len, fd, dst, drv->process, wanted_capability);
 715
 716        return 0;
 717}
 718
 719static int read_convert_config(const char *var, const char *value, void *cb)
 720{
 721        const char *key, *name;
 722        int namelen;
 723        struct convert_driver *drv;
 724
 725        /*
 726         * External conversion drivers are configured using
 727         * "filter.<name>.variable".
 728         */
 729        if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 730                return 0;
 731        for (drv = user_convert; drv; drv = drv->next)
 732                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 733                        break;
 734        if (!drv) {
 735                drv = xcalloc(1, sizeof(struct convert_driver));
 736                drv->name = xmemdupz(name, namelen);
 737                *user_convert_tail = drv;
 738                user_convert_tail = &(drv->next);
 739        }
 740
 741        /*
 742         * filter.<name>.smudge and filter.<name>.clean specifies
 743         * the command line:
 744         *
 745         *      command-line
 746         *
 747         * The command-line will not be interpolated in any way.
 748         */
 749
 750        if (!strcmp("smudge", key))
 751                return git_config_string(&drv->smudge, var, value);
 752
 753        if (!strcmp("clean", key))
 754                return git_config_string(&drv->clean, var, value);
 755
 756        if (!strcmp("process", key))
 757                return git_config_string(&drv->process, var, value);
 758
 759        if (!strcmp("required", key)) {
 760                drv->required = git_config_bool(var, value);
 761                return 0;
 762        }
 763
 764        return 0;
 765}
 766
 767static int count_ident(const char *cp, unsigned long size)
 768{
 769        /*
 770         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 771         */
 772        int cnt = 0;
 773        char ch;
 774
 775        while (size) {
 776                ch = *cp++;
 777                size--;
 778                if (ch != '$')
 779                        continue;
 780                if (size < 3)
 781                        break;
 782                if (memcmp("Id", cp, 2))
 783                        continue;
 784                ch = cp[2];
 785                cp += 3;
 786                size -= 3;
 787                if (ch == '$')
 788                        cnt++; /* $Id$ */
 789                if (ch != ':')
 790                        continue;
 791
 792                /*
 793                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 794                 */
 795                while (size) {
 796                        ch = *cp++;
 797                        size--;
 798                        if (ch == '$') {
 799                                cnt++;
 800                                break;
 801                        }
 802                        if (ch == '\n')
 803                                break;
 804                }
 805        }
 806        return cnt;
 807}
 808
 809static int ident_to_git(const char *path, const char *src, size_t len,
 810                        struct strbuf *buf, int ident)
 811{
 812        char *dst, *dollar;
 813
 814        if (!ident || (src && !count_ident(src, len)))
 815                return 0;
 816
 817        if (!buf)
 818                return 1;
 819
 820        /* only grow if not in place */
 821        if (strbuf_avail(buf) + buf->len < len)
 822                strbuf_grow(buf, len - buf->len);
 823        dst = buf->buf;
 824        for (;;) {
 825                dollar = memchr(src, '$', len);
 826                if (!dollar)
 827                        break;
 828                memmove(dst, src, dollar + 1 - src);
 829                dst += dollar + 1 - src;
 830                len -= dollar + 1 - src;
 831                src  = dollar + 1;
 832
 833                if (len > 3 && !memcmp(src, "Id:", 3)) {
 834                        dollar = memchr(src + 3, '$', len - 3);
 835                        if (!dollar)
 836                                break;
 837                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 838                                /* Line break before the next dollar. */
 839                                continue;
 840                        }
 841
 842                        memcpy(dst, "Id$", 3);
 843                        dst += 3;
 844                        len -= dollar + 1 - src;
 845                        src  = dollar + 1;
 846                }
 847        }
 848        memmove(dst, src, len);
 849        strbuf_setlen(buf, dst + len - buf->buf);
 850        return 1;
 851}
 852
 853static int ident_to_worktree(const char *path, const char *src, size_t len,
 854                             struct strbuf *buf, int ident)
 855{
 856        unsigned char sha1[20];
 857        char *to_free = NULL, *dollar, *spc;
 858        int cnt;
 859
 860        if (!ident)
 861                return 0;
 862
 863        cnt = count_ident(src, len);
 864        if (!cnt)
 865                return 0;
 866
 867        /* are we "faking" in place editing ? */
 868        if (src == buf->buf)
 869                to_free = strbuf_detach(buf, NULL);
 870        hash_sha1_file(src, len, "blob", sha1);
 871
 872        strbuf_grow(buf, len + cnt * 43);
 873        for (;;) {
 874                /* step 1: run to the next '$' */
 875                dollar = memchr(src, '$', len);
 876                if (!dollar)
 877                        break;
 878                strbuf_add(buf, src, dollar + 1 - src);
 879                len -= dollar + 1 - src;
 880                src  = dollar + 1;
 881
 882                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 883                if (len < 3 || memcmp("Id", src, 2))
 884                        continue;
 885
 886                /* step 3: skip over Id$ or Id:xxxxx$ */
 887                if (src[2] == '$') {
 888                        src += 3;
 889                        len -= 3;
 890                } else if (src[2] == ':') {
 891                        /*
 892                         * It's possible that an expanded Id has crept its way into the
 893                         * repository, we cope with that by stripping the expansion out.
 894                         * This is probably not a good idea, since it will cause changes
 895                         * on checkout, which won't go away by stash, but let's keep it
 896                         * for git-style ids.
 897                         */
 898                        dollar = memchr(src + 3, '$', len - 3);
 899                        if (!dollar) {
 900                                /* incomplete keyword, no more '$', so just quit the loop */
 901                                break;
 902                        }
 903
 904                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 905                                /* Line break before the next dollar. */
 906                                continue;
 907                        }
 908
 909                        spc = memchr(src + 4, ' ', dollar - src - 4);
 910                        if (spc && spc < dollar-1) {
 911                                /* There are spaces in unexpected places.
 912                                 * This is probably an id from some other
 913                                 * versioning system. Keep it for now.
 914                                 */
 915                                continue;
 916                        }
 917
 918                        len -= dollar + 1 - src;
 919                        src  = dollar + 1;
 920                } else {
 921                        /* it wasn't a "Id$" or "Id:xxxx$" */
 922                        continue;
 923                }
 924
 925                /* step 4: substitute */
 926                strbuf_addstr(buf, "Id: ");
 927                strbuf_add(buf, sha1_to_hex(sha1), 40);
 928                strbuf_addstr(buf, " $");
 929        }
 930        strbuf_add(buf, src, len);
 931
 932        free(to_free);
 933        return 1;
 934}
 935
 936static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
 937{
 938        const char *value = check->value;
 939
 940        if (ATTR_TRUE(value))
 941                return CRLF_TEXT;
 942        else if (ATTR_FALSE(value))
 943                return CRLF_BINARY;
 944        else if (ATTR_UNSET(value))
 945                ;
 946        else if (!strcmp(value, "input"))
 947                return CRLF_TEXT_INPUT;
 948        else if (!strcmp(value, "auto"))
 949                return CRLF_AUTO;
 950        return CRLF_UNDEFINED;
 951}
 952
 953static enum eol git_path_check_eol(struct attr_check_item *check)
 954{
 955        const char *value = check->value;
 956
 957        if (ATTR_UNSET(value))
 958                ;
 959        else if (!strcmp(value, "lf"))
 960                return EOL_LF;
 961        else if (!strcmp(value, "crlf"))
 962                return EOL_CRLF;
 963        return EOL_UNSET;
 964}
 965
 966static struct convert_driver *git_path_check_convert(struct attr_check_item *check)
 967{
 968        const char *value = check->value;
 969        struct convert_driver *drv;
 970
 971        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
 972                return NULL;
 973        for (drv = user_convert; drv; drv = drv->next)
 974                if (!strcmp(value, drv->name))
 975                        return drv;
 976        return NULL;
 977}
 978
 979static int git_path_check_ident(struct attr_check_item *check)
 980{
 981        const char *value = check->value;
 982
 983        return !!ATTR_TRUE(value);
 984}
 985
 986struct conv_attrs {
 987        struct convert_driver *drv;
 988        enum crlf_action attr_action; /* What attr says */
 989        enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
 990        int ident;
 991};
 992
 993static void convert_attrs(struct conv_attrs *ca, const char *path)
 994{
 995        static struct attr_check *check;
 996
 997        if (!check) {
 998                check = attr_check_initl("crlf", "ident", "filter",
 999                                         "eol", "text", NULL);
1000                user_convert_tail = &user_convert;
1001                git_config(read_convert_config, NULL);
1002        }
1003
1004        if (!git_check_attr(path, check)) {
1005                struct attr_check_item *ccheck = check->items;
1006                ca->crlf_action = git_path_check_crlf(ccheck + 4);
1007                if (ca->crlf_action == CRLF_UNDEFINED)
1008                        ca->crlf_action = git_path_check_crlf(ccheck + 0);
1009                ca->attr_action = ca->crlf_action;
1010                ca->ident = git_path_check_ident(ccheck + 1);
1011                ca->drv = git_path_check_convert(ccheck + 2);
1012                if (ca->crlf_action != CRLF_BINARY) {
1013                        enum eol eol_attr = git_path_check_eol(ccheck + 3);
1014                        if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
1015                                ca->crlf_action = CRLF_AUTO_INPUT;
1016                        else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
1017                                ca->crlf_action = CRLF_AUTO_CRLF;
1018                        else if (eol_attr == EOL_LF)
1019                                ca->crlf_action = CRLF_TEXT_INPUT;
1020                        else if (eol_attr == EOL_CRLF)
1021                                ca->crlf_action = CRLF_TEXT_CRLF;
1022                }
1023                ca->attr_action = ca->crlf_action;
1024        } else {
1025                ca->drv = NULL;
1026                ca->crlf_action = CRLF_UNDEFINED;
1027                ca->ident = 0;
1028        }
1029        if (ca->crlf_action == CRLF_TEXT)
1030                ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
1031        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
1032                ca->crlf_action = CRLF_BINARY;
1033        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
1034                ca->crlf_action = CRLF_AUTO_CRLF;
1035        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
1036                ca->crlf_action = CRLF_AUTO_INPUT;
1037}
1038
1039int would_convert_to_git_filter_fd(const char *path)
1040{
1041        struct conv_attrs ca;
1042
1043        convert_attrs(&ca, path);
1044        if (!ca.drv)
1045                return 0;
1046
1047        /*
1048         * Apply a filter to an fd only if the filter is required to succeed.
1049         * We must die if the filter fails, because the original data before
1050         * filtering is not available.
1051         */
1052        if (!ca.drv->required)
1053                return 0;
1054
1055        return apply_filter(path, NULL, 0, -1, NULL, ca.drv, CAP_CLEAN);
1056}
1057
1058const char *get_convert_attr_ascii(const char *path)
1059{
1060        struct conv_attrs ca;
1061
1062        convert_attrs(&ca, path);
1063        switch (ca.attr_action) {
1064        case CRLF_UNDEFINED:
1065                return "";
1066        case CRLF_BINARY:
1067                return "-text";
1068        case CRLF_TEXT:
1069                return "text";
1070        case CRLF_TEXT_INPUT:
1071                return "text eol=lf";
1072        case CRLF_TEXT_CRLF:
1073                return "text eol=crlf";
1074        case CRLF_AUTO:
1075                return "text=auto";
1076        case CRLF_AUTO_CRLF:
1077                return "text=auto eol=crlf";
1078        case CRLF_AUTO_INPUT:
1079                return "text=auto eol=lf";
1080        }
1081        return "";
1082}
1083
1084int convert_to_git(const char *path, const char *src, size_t len,
1085                   struct strbuf *dst, enum safe_crlf checksafe)
1086{
1087        int ret = 0;
1088        struct conv_attrs ca;
1089
1090        convert_attrs(&ca, path);
1091
1092        ret |= apply_filter(path, src, len, -1, dst, ca.drv, CAP_CLEAN);
1093        if (!ret && ca.drv && ca.drv->required)
1094                die("%s: clean filter '%s' failed", path, ca.drv->name);
1095
1096        if (ret && dst) {
1097                src = dst->buf;
1098                len = dst->len;
1099        }
1100        ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
1101        if (ret && dst) {
1102                src = dst->buf;
1103                len = dst->len;
1104        }
1105        return ret | ident_to_git(path, src, len, dst, ca.ident);
1106}
1107
1108void convert_to_git_filter_fd(const char *path, int fd, struct strbuf *dst,
1109                              enum safe_crlf checksafe)
1110{
1111        struct conv_attrs ca;
1112        convert_attrs(&ca, path);
1113
1114        assert(ca.drv);
1115        assert(ca.drv->clean || ca.drv->process);
1116
1117        if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN))
1118                die("%s: clean filter '%s' failed", path, ca.drv->name);
1119
1120        crlf_to_git(path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
1121        ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
1122}
1123
1124static int convert_to_working_tree_internal(const char *path, const char *src,
1125                                            size_t len, struct strbuf *dst,
1126                                            int normalizing)
1127{
1128        int ret = 0, ret_filter = 0;
1129        struct conv_attrs ca;
1130
1131        convert_attrs(&ca, path);
1132
1133        ret |= ident_to_worktree(path, src, len, dst, ca.ident);
1134        if (ret) {
1135                src = dst->buf;
1136                len = dst->len;
1137        }
1138        /*
1139         * CRLF conversion can be skipped if normalizing, unless there
1140         * is a smudge or process filter (even if the process filter doesn't
1141         * support smudge).  The filters might expect CRLFs.
1142         */
1143        if ((ca.drv && (ca.drv->smudge || ca.drv->process)) || !normalizing) {
1144                ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
1145                if (ret) {
1146                        src = dst->buf;
1147                        len = dst->len;
1148                }
1149        }
1150
1151        ret_filter = apply_filter(path, src, len, -1, dst, ca.drv, CAP_SMUDGE);
1152        if (!ret_filter && ca.drv && ca.drv->required)
1153                die("%s: smudge filter %s failed", path, ca.drv->name);
1154
1155        return ret | ret_filter;
1156}
1157
1158int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
1159{
1160        return convert_to_working_tree_internal(path, src, len, dst, 0);
1161}
1162
1163int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
1164{
1165        int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
1166        if (ret) {
1167                src = dst->buf;
1168                len = dst->len;
1169        }
1170        return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_RENORMALIZE);
1171}
1172
1173/*****************************************************************
1174 *
1175 * Streaming conversion support
1176 *
1177 *****************************************************************/
1178
1179typedef int (*filter_fn)(struct stream_filter *,
1180                         const char *input, size_t *isize_p,
1181                         char *output, size_t *osize_p);
1182typedef void (*free_fn)(struct stream_filter *);
1183
1184struct stream_filter_vtbl {
1185        filter_fn filter;
1186        free_fn free;
1187};
1188
1189struct stream_filter {
1190        struct stream_filter_vtbl *vtbl;
1191};
1192
1193static int null_filter_fn(struct stream_filter *filter,
1194                          const char *input, size_t *isize_p,
1195                          char *output, size_t *osize_p)
1196{
1197        size_t count;
1198
1199        if (!input)
1200                return 0; /* we do not keep any states */
1201        count = *isize_p;
1202        if (*osize_p < count)
1203                count = *osize_p;
1204        if (count) {
1205                memmove(output, input, count);
1206                *isize_p -= count;
1207                *osize_p -= count;
1208        }
1209        return 0;
1210}
1211
1212static void null_free_fn(struct stream_filter *filter)
1213{
1214        ; /* nothing -- null instances are shared */
1215}
1216
1217static struct stream_filter_vtbl null_vtbl = {
1218        null_filter_fn,
1219        null_free_fn,
1220};
1221
1222static struct stream_filter null_filter_singleton = {
1223        &null_vtbl,
1224};
1225
1226int is_null_stream_filter(struct stream_filter *filter)
1227{
1228        return filter == &null_filter_singleton;
1229}
1230
1231
1232/*
1233 * LF-to-CRLF filter
1234 */
1235
1236struct lf_to_crlf_filter {
1237        struct stream_filter filter;
1238        unsigned has_held:1;
1239        char held;
1240};
1241
1242static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1243                                const char *input, size_t *isize_p,
1244                                char *output, size_t *osize_p)
1245{
1246        size_t count, o = 0;
1247        struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1248
1249        /*
1250         * We may be holding onto the CR to see if it is followed by a
1251         * LF, in which case we would need to go to the main loop.
1252         * Otherwise, just emit it to the output stream.
1253         */
1254        if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1255                output[o++] = lf_to_crlf->held;
1256                lf_to_crlf->has_held = 0;
1257        }
1258
1259        /* We are told to drain */
1260        if (!input) {
1261                *osize_p -= o;
1262                return 0;
1263        }
1264
1265        count = *isize_p;
1266        if (count || lf_to_crlf->has_held) {
1267                size_t i;
1268                int was_cr = 0;
1269
1270                if (lf_to_crlf->has_held) {
1271                        was_cr = 1;
1272                        lf_to_crlf->has_held = 0;
1273                }
1274
1275                for (i = 0; o < *osize_p && i < count; i++) {
1276                        char ch = input[i];
1277
1278                        if (ch == '\n') {
1279                                output[o++] = '\r';
1280                        } else if (was_cr) {
1281                                /*
1282                                 * Previous round saw CR and it is not followed
1283                                 * by a LF; emit the CR before processing the
1284                                 * current character.
1285                                 */
1286                                output[o++] = '\r';
1287                        }
1288
1289                        /*
1290                         * We may have consumed the last output slot,
1291                         * in which case we need to break out of this
1292                         * loop; hold the current character before
1293                         * returning.
1294                         */
1295                        if (*osize_p <= o) {
1296                                lf_to_crlf->has_held = 1;
1297                                lf_to_crlf->held = ch;
1298                                continue; /* break but increment i */
1299                        }
1300
1301                        if (ch == '\r') {
1302                                was_cr = 1;
1303                                continue;
1304                        }
1305
1306                        was_cr = 0;
1307                        output[o++] = ch;
1308                }
1309
1310                *osize_p -= o;
1311                *isize_p -= i;
1312
1313                if (!lf_to_crlf->has_held && was_cr) {
1314                        lf_to_crlf->has_held = 1;
1315                        lf_to_crlf->held = '\r';
1316                }
1317        }
1318        return 0;
1319}
1320
1321static void lf_to_crlf_free_fn(struct stream_filter *filter)
1322{
1323        free(filter);
1324}
1325
1326static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1327        lf_to_crlf_filter_fn,
1328        lf_to_crlf_free_fn,
1329};
1330
1331static struct stream_filter *lf_to_crlf_filter(void)
1332{
1333        struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1334
1335        lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1336        return (struct stream_filter *)lf_to_crlf;
1337}
1338
1339/*
1340 * Cascade filter
1341 */
1342#define FILTER_BUFFER 1024
1343struct cascade_filter {
1344        struct stream_filter filter;
1345        struct stream_filter *one;
1346        struct stream_filter *two;
1347        char buf[FILTER_BUFFER];
1348        int end, ptr;
1349};
1350
1351static int cascade_filter_fn(struct stream_filter *filter,
1352                             const char *input, size_t *isize_p,
1353                             char *output, size_t *osize_p)
1354{
1355        struct cascade_filter *cas = (struct cascade_filter *) filter;
1356        size_t filled = 0;
1357        size_t sz = *osize_p;
1358        size_t to_feed, remaining;
1359
1360        /*
1361         * input -- (one) --> buf -- (two) --> output
1362         */
1363        while (filled < sz) {
1364                remaining = sz - filled;
1365
1366                /* do we already have something to feed two with? */
1367                if (cas->ptr < cas->end) {
1368                        to_feed = cas->end - cas->ptr;
1369                        if (stream_filter(cas->two,
1370                                          cas->buf + cas->ptr, &to_feed,
1371                                          output + filled, &remaining))
1372                                return -1;
1373                        cas->ptr += (cas->end - cas->ptr) - to_feed;
1374                        filled = sz - remaining;
1375                        continue;
1376                }
1377
1378                /* feed one from upstream and have it emit into our buffer */
1379                to_feed = input ? *isize_p : 0;
1380                if (input && !to_feed)
1381                        break;
1382                remaining = sizeof(cas->buf);
1383                if (stream_filter(cas->one,
1384                                  input, &to_feed,
1385                                  cas->buf, &remaining))
1386                        return -1;
1387                cas->end = sizeof(cas->buf) - remaining;
1388                cas->ptr = 0;
1389                if (input) {
1390                        size_t fed = *isize_p - to_feed;
1391                        *isize_p -= fed;
1392                        input += fed;
1393                }
1394
1395                /* do we know that we drained one completely? */
1396                if (input || cas->end)
1397                        continue;
1398
1399                /* tell two to drain; we have nothing more to give it */
1400                to_feed = 0;
1401                remaining = sz - filled;
1402                if (stream_filter(cas->two,
1403                                  NULL, &to_feed,
1404                                  output + filled, &remaining))
1405                        return -1;
1406                if (remaining == (sz - filled))
1407                        break; /* completely drained two */
1408                filled = sz - remaining;
1409        }
1410        *osize_p -= filled;
1411        return 0;
1412}
1413
1414static void cascade_free_fn(struct stream_filter *filter)
1415{
1416        struct cascade_filter *cas = (struct cascade_filter *)filter;
1417        free_stream_filter(cas->one);
1418        free_stream_filter(cas->two);
1419        free(filter);
1420}
1421
1422static struct stream_filter_vtbl cascade_vtbl = {
1423        cascade_filter_fn,
1424        cascade_free_fn,
1425};
1426
1427static struct stream_filter *cascade_filter(struct stream_filter *one,
1428                                            struct stream_filter *two)
1429{
1430        struct cascade_filter *cascade;
1431
1432        if (!one || is_null_stream_filter(one))
1433                return two;
1434        if (!two || is_null_stream_filter(two))
1435                return one;
1436
1437        cascade = xmalloc(sizeof(*cascade));
1438        cascade->one = one;
1439        cascade->two = two;
1440        cascade->end = cascade->ptr = 0;
1441        cascade->filter.vtbl = &cascade_vtbl;
1442        return (struct stream_filter *)cascade;
1443}
1444
1445/*
1446 * ident filter
1447 */
1448#define IDENT_DRAINING (-1)
1449#define IDENT_SKIPPING (-2)
1450struct ident_filter {
1451        struct stream_filter filter;
1452        struct strbuf left;
1453        int state;
1454        char ident[45]; /* ": x40 $" */
1455};
1456
1457static int is_foreign_ident(const char *str)
1458{
1459        int i;
1460
1461        if (!skip_prefix(str, "$Id: ", &str))
1462                return 0;
1463        for (i = 0; str[i]; i++) {
1464                if (isspace(str[i]) && str[i+1] != '$')
1465                        return 1;
1466        }
1467        return 0;
1468}
1469
1470static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1471{
1472        size_t to_drain = ident->left.len;
1473
1474        if (*osize_p < to_drain)
1475                to_drain = *osize_p;
1476        if (to_drain) {
1477                memcpy(*output_p, ident->left.buf, to_drain);
1478                strbuf_remove(&ident->left, 0, to_drain);
1479                *output_p += to_drain;
1480                *osize_p -= to_drain;
1481        }
1482        if (!ident->left.len)
1483                ident->state = 0;
1484}
1485
1486static int ident_filter_fn(struct stream_filter *filter,
1487                           const char *input, size_t *isize_p,
1488                           char *output, size_t *osize_p)
1489{
1490        struct ident_filter *ident = (struct ident_filter *)filter;
1491        static const char head[] = "$Id";
1492
1493        if (!input) {
1494                /* drain upon eof */
1495                switch (ident->state) {
1496                default:
1497                        strbuf_add(&ident->left, head, ident->state);
1498                case IDENT_SKIPPING:
1499                        /* fallthru */
1500                case IDENT_DRAINING:
1501                        ident_drain(ident, &output, osize_p);
1502                }
1503                return 0;
1504        }
1505
1506        while (*isize_p || (ident->state == IDENT_DRAINING)) {
1507                int ch;
1508
1509                if (ident->state == IDENT_DRAINING) {
1510                        ident_drain(ident, &output, osize_p);
1511                        if (!*osize_p)
1512                                break;
1513                        continue;
1514                }
1515
1516                ch = *(input++);
1517                (*isize_p)--;
1518
1519                if (ident->state == IDENT_SKIPPING) {
1520                        /*
1521                         * Skipping until '$' or LF, but keeping them
1522                         * in case it is a foreign ident.
1523                         */
1524                        strbuf_addch(&ident->left, ch);
1525                        if (ch != '\n' && ch != '$')
1526                                continue;
1527                        if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1528                                strbuf_setlen(&ident->left, sizeof(head) - 1);
1529                                strbuf_addstr(&ident->left, ident->ident);
1530                        }
1531                        ident->state = IDENT_DRAINING;
1532                        continue;
1533                }
1534
1535                if (ident->state < sizeof(head) &&
1536                    head[ident->state] == ch) {
1537                        ident->state++;
1538                        continue;
1539                }
1540
1541                if (ident->state)
1542                        strbuf_add(&ident->left, head, ident->state);
1543                if (ident->state == sizeof(head) - 1) {
1544                        if (ch != ':' && ch != '$') {
1545                                strbuf_addch(&ident->left, ch);
1546                                ident->state = 0;
1547                                continue;
1548                        }
1549
1550                        if (ch == ':') {
1551                                strbuf_addch(&ident->left, ch);
1552                                ident->state = IDENT_SKIPPING;
1553                        } else {
1554                                strbuf_addstr(&ident->left, ident->ident);
1555                                ident->state = IDENT_DRAINING;
1556                        }
1557                        continue;
1558                }
1559
1560                strbuf_addch(&ident->left, ch);
1561                ident->state = IDENT_DRAINING;
1562        }
1563        return 0;
1564}
1565
1566static void ident_free_fn(struct stream_filter *filter)
1567{
1568        struct ident_filter *ident = (struct ident_filter *)filter;
1569        strbuf_release(&ident->left);
1570        free(filter);
1571}
1572
1573static struct stream_filter_vtbl ident_vtbl = {
1574        ident_filter_fn,
1575        ident_free_fn,
1576};
1577
1578static struct stream_filter *ident_filter(const unsigned char *sha1)
1579{
1580        struct ident_filter *ident = xmalloc(sizeof(*ident));
1581
1582        xsnprintf(ident->ident, sizeof(ident->ident),
1583                  ": %s $", sha1_to_hex(sha1));
1584        strbuf_init(&ident->left, 0);
1585        ident->filter.vtbl = &ident_vtbl;
1586        ident->state = 0;
1587        return (struct stream_filter *)ident;
1588}
1589
1590/*
1591 * Return an appropriately constructed filter for the path, or NULL if
1592 * the contents cannot be filtered without reading the whole thing
1593 * in-core.
1594 *
1595 * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1596 * large binary blob you would want us not to slurp into the memory!
1597 */
1598struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1599{
1600        struct conv_attrs ca;
1601        struct stream_filter *filter = NULL;
1602
1603        convert_attrs(&ca, path);
1604        if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
1605                return NULL;
1606
1607        if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1608                return NULL;
1609
1610        if (ca.ident)
1611                filter = ident_filter(sha1);
1612
1613        if (output_eol(ca.crlf_action) == EOL_CRLF)
1614                filter = cascade_filter(filter, lf_to_crlf_filter());
1615        else
1616                filter = cascade_filter(filter, &null_filter_singleton);
1617
1618        return filter;
1619}
1620
1621void free_stream_filter(struct stream_filter *filter)
1622{
1623        filter->vtbl->free(filter);
1624}
1625
1626int stream_filter(struct stream_filter *filter,
1627                  const char *input, size_t *isize_p,
1628                  char *output, size_t *osize_p)
1629{
1630        return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1631}