convert.con commit config: don't include config.h by default (b2141fc)
   1#include "cache.h"
   2#include "config.h"
   3#include "attr.h"
   4#include "run-command.h"
   5#include "quote.h"
   6#include "sigchain.h"
   7#include "pkt-line.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 hashmap_entry ent; /* must be the first member! */
 502        unsigned int supported_capabilities;
 503        const char *cmd;
 504        struct child_process process;
 505};
 506
 507static int cmd_process_map_initialized;
 508static struct hashmap cmd_process_map;
 509
 510static int cmd2process_cmp(const struct cmd2process *e1,
 511                           const struct cmd2process *e2,
 512                           const void *unused)
 513{
 514        return strcmp(e1->cmd, e2->cmd);
 515}
 516
 517static struct cmd2process *find_multi_file_filter_entry(struct hashmap *hashmap, const char *cmd)
 518{
 519        struct cmd2process key;
 520        hashmap_entry_init(&key, strhash(cmd));
 521        key.cmd = cmd;
 522        return hashmap_get(hashmap, &key, NULL);
 523}
 524
 525static int packet_write_list(int fd, const char *line, ...)
 526{
 527        va_list args;
 528        int err;
 529        va_start(args, line);
 530        for (;;) {
 531                if (!line)
 532                        break;
 533                if (strlen(line) > LARGE_PACKET_DATA_MAX)
 534                        return -1;
 535                err = packet_write_fmt_gently(fd, "%s\n", line);
 536                if (err)
 537                        return err;
 538                line = va_arg(args, const char*);
 539        }
 540        va_end(args);
 541        return packet_flush_gently(fd);
 542}
 543
 544static void read_multi_file_filter_status(int fd, struct strbuf *status)
 545{
 546        struct strbuf **pair;
 547        char *line;
 548        for (;;) {
 549                line = packet_read_line(fd, NULL);
 550                if (!line)
 551                        break;
 552                pair = strbuf_split_str(line, '=', 2);
 553                if (pair[0] && pair[0]->len && pair[1]) {
 554                        /* the last "status=<foo>" line wins */
 555                        if (!strcmp(pair[0]->buf, "status=")) {
 556                                strbuf_reset(status);
 557                                strbuf_addbuf(status, pair[1]);
 558                        }
 559                }
 560                strbuf_list_free(pair);
 561        }
 562}
 563
 564static void kill_multi_file_filter(struct hashmap *hashmap, struct cmd2process *entry)
 565{
 566        if (!entry)
 567                return;
 568
 569        entry->process.clean_on_exit = 0;
 570        kill(entry->process.pid, SIGTERM);
 571        finish_command(&entry->process);
 572
 573        hashmap_remove(hashmap, entry, NULL);
 574        free(entry);
 575}
 576
 577static void stop_multi_file_filter(struct child_process *process)
 578{
 579        sigchain_push(SIGPIPE, SIG_IGN);
 580        /* Closing the pipe signals the filter to initiate a shutdown. */
 581        close(process->in);
 582        close(process->out);
 583        sigchain_pop(SIGPIPE);
 584        /* Finish command will wait until the shutdown is complete. */
 585        finish_command(process);
 586}
 587
 588static struct cmd2process *start_multi_file_filter(struct hashmap *hashmap, const char *cmd)
 589{
 590        int err;
 591        struct cmd2process *entry;
 592        struct child_process *process;
 593        const char *argv[] = { cmd, NULL };
 594        struct string_list cap_list = STRING_LIST_INIT_NODUP;
 595        char *cap_buf;
 596        const char *cap_name;
 597
 598        entry = xmalloc(sizeof(*entry));
 599        entry->cmd = cmd;
 600        entry->supported_capabilities = 0;
 601        process = &entry->process;
 602
 603        child_process_init(process);
 604        process->argv = argv;
 605        process->use_shell = 1;
 606        process->in = -1;
 607        process->out = -1;
 608        process->clean_on_exit = 1;
 609        process->clean_on_exit_handler = stop_multi_file_filter;
 610
 611        if (start_command(process)) {
 612                error("cannot fork to run external filter '%s'", cmd);
 613                return NULL;
 614        }
 615
 616        hashmap_entry_init(entry, strhash(cmd));
 617
 618        sigchain_push(SIGPIPE, SIG_IGN);
 619
 620        err = packet_write_list(process->in, "git-filter-client", "version=2", NULL);
 621        if (err)
 622                goto done;
 623
 624        err = strcmp(packet_read_line(process->out, NULL), "git-filter-server");
 625        if (err) {
 626                error("external filter '%s' does not support filter protocol version 2", cmd);
 627                goto done;
 628        }
 629        err = strcmp(packet_read_line(process->out, NULL), "version=2");
 630        if (err)
 631                goto done;
 632        err = packet_read_line(process->out, NULL) != NULL;
 633        if (err)
 634                goto done;
 635
 636        err = packet_write_list(process->in, "capability=clean", "capability=smudge", NULL);
 637
 638        for (;;) {
 639                cap_buf = packet_read_line(process->out, NULL);
 640                if (!cap_buf)
 641                        break;
 642                string_list_split_in_place(&cap_list, cap_buf, '=', 1);
 643
 644                if (cap_list.nr != 2 || strcmp(cap_list.items[0].string, "capability"))
 645                        continue;
 646
 647                cap_name = cap_list.items[1].string;
 648                if (!strcmp(cap_name, "clean")) {
 649                        entry->supported_capabilities |= CAP_CLEAN;
 650                } else if (!strcmp(cap_name, "smudge")) {
 651                        entry->supported_capabilities |= CAP_SMUDGE;
 652                } else {
 653                        warning(
 654                                "external filter '%s' requested unsupported filter capability '%s'",
 655                                cmd, cap_name
 656                        );
 657                }
 658
 659                string_list_clear(&cap_list, 0);
 660        }
 661
 662done:
 663        sigchain_pop(SIGPIPE);
 664
 665        if (err || errno == EPIPE) {
 666                error("initialization for external filter '%s' failed", cmd);
 667                kill_multi_file_filter(hashmap, entry);
 668                return NULL;
 669        }
 670
 671        hashmap_add(hashmap, entry);
 672        return entry;
 673}
 674
 675static int apply_multi_file_filter(const char *path, const char *src, size_t len,
 676                                   int fd, struct strbuf *dst, const char *cmd,
 677                                   const unsigned int wanted_capability)
 678{
 679        int err;
 680        struct cmd2process *entry;
 681        struct child_process *process;
 682        struct strbuf nbuf = STRBUF_INIT;
 683        struct strbuf filter_status = STRBUF_INIT;
 684        const char *filter_type;
 685
 686        if (!cmd_process_map_initialized) {
 687                cmd_process_map_initialized = 1;
 688                hashmap_init(&cmd_process_map, (hashmap_cmp_fn) cmd2process_cmp, 0);
 689                entry = NULL;
 690        } else {
 691                entry = find_multi_file_filter_entry(&cmd_process_map, cmd);
 692        }
 693
 694        fflush(NULL);
 695
 696        if (!entry) {
 697                entry = start_multi_file_filter(&cmd_process_map, cmd);
 698                if (!entry)
 699                        return 0;
 700        }
 701        process = &entry->process;
 702
 703        if (!(wanted_capability & entry->supported_capabilities))
 704                return 0;
 705
 706        if (CAP_CLEAN & wanted_capability)
 707                filter_type = "clean";
 708        else if (CAP_SMUDGE & wanted_capability)
 709                filter_type = "smudge";
 710        else
 711                die("unexpected filter type");
 712
 713        sigchain_push(SIGPIPE, SIG_IGN);
 714
 715        assert(strlen(filter_type) < LARGE_PACKET_DATA_MAX - strlen("command=\n"));
 716        err = packet_write_fmt_gently(process->in, "command=%s\n", filter_type);
 717        if (err)
 718                goto done;
 719
 720        err = strlen(path) > LARGE_PACKET_DATA_MAX - strlen("pathname=\n");
 721        if (err) {
 722                error("path name too long for external filter");
 723                goto done;
 724        }
 725
 726        err = packet_write_fmt_gently(process->in, "pathname=%s\n", path);
 727        if (err)
 728                goto done;
 729
 730        err = packet_flush_gently(process->in);
 731        if (err)
 732                goto done;
 733
 734        if (fd >= 0)
 735                err = write_packetized_from_fd(fd, process->in);
 736        else
 737                err = write_packetized_from_buf(src, len, process->in);
 738        if (err)
 739                goto done;
 740
 741        read_multi_file_filter_status(process->out, &filter_status);
 742        err = strcmp(filter_status.buf, "success");
 743        if (err)
 744                goto done;
 745
 746        err = read_packetized_to_strbuf(process->out, &nbuf) < 0;
 747        if (err)
 748                goto done;
 749
 750        read_multi_file_filter_status(process->out, &filter_status);
 751        err = strcmp(filter_status.buf, "success");
 752
 753done:
 754        sigchain_pop(SIGPIPE);
 755
 756        if (err || errno == EPIPE) {
 757                if (!strcmp(filter_status.buf, "error")) {
 758                        /* The filter signaled a problem with the file. */
 759                } else if (!strcmp(filter_status.buf, "abort")) {
 760                        /*
 761                         * The filter signaled a permanent problem. Don't try to filter
 762                         * files with the same command for the lifetime of the current
 763                         * Git process.
 764                         */
 765                         entry->supported_capabilities &= ~wanted_capability;
 766                } else {
 767                        /*
 768                         * Something went wrong with the protocol filter.
 769                         * Force shutdown and restart if another blob requires filtering.
 770                         */
 771                        error("external filter '%s' failed", cmd);
 772                        kill_multi_file_filter(&cmd_process_map, entry);
 773                }
 774        } else {
 775                strbuf_swap(dst, &nbuf);
 776        }
 777        strbuf_release(&nbuf);
 778        return !err;
 779}
 780
 781static struct convert_driver {
 782        const char *name;
 783        struct convert_driver *next;
 784        const char *smudge;
 785        const char *clean;
 786        const char *process;
 787        int required;
 788} *user_convert, **user_convert_tail;
 789
 790static int apply_filter(const char *path, const char *src, size_t len,
 791                        int fd, struct strbuf *dst, struct convert_driver *drv,
 792                        const unsigned int wanted_capability)
 793{
 794        const char *cmd = NULL;
 795
 796        if (!drv)
 797                return 0;
 798
 799        if (!dst)
 800                return 1;
 801
 802        if ((CAP_CLEAN & wanted_capability) && !drv->process && drv->clean)
 803                cmd = drv->clean;
 804        else if ((CAP_SMUDGE & wanted_capability) && !drv->process && drv->smudge)
 805                cmd = drv->smudge;
 806
 807        if (cmd && *cmd)
 808                return apply_single_file_filter(path, src, len, fd, dst, cmd);
 809        else if (drv->process && *drv->process)
 810                return apply_multi_file_filter(path, src, len, fd, dst, drv->process, wanted_capability);
 811
 812        return 0;
 813}
 814
 815static int read_convert_config(const char *var, const char *value, void *cb)
 816{
 817        const char *key, *name;
 818        int namelen;
 819        struct convert_driver *drv;
 820
 821        /*
 822         * External conversion drivers are configured using
 823         * "filter.<name>.variable".
 824         */
 825        if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 826                return 0;
 827        for (drv = user_convert; drv; drv = drv->next)
 828                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 829                        break;
 830        if (!drv) {
 831                drv = xcalloc(1, sizeof(struct convert_driver));
 832                drv->name = xmemdupz(name, namelen);
 833                *user_convert_tail = drv;
 834                user_convert_tail = &(drv->next);
 835        }
 836
 837        /*
 838         * filter.<name>.smudge and filter.<name>.clean specifies
 839         * the command line:
 840         *
 841         *      command-line
 842         *
 843         * The command-line will not be interpolated in any way.
 844         */
 845
 846        if (!strcmp("smudge", key))
 847                return git_config_string(&drv->smudge, var, value);
 848
 849        if (!strcmp("clean", key))
 850                return git_config_string(&drv->clean, var, value);
 851
 852        if (!strcmp("process", key))
 853                return git_config_string(&drv->process, var, value);
 854
 855        if (!strcmp("required", key)) {
 856                drv->required = git_config_bool(var, value);
 857                return 0;
 858        }
 859
 860        return 0;
 861}
 862
 863static int count_ident(const char *cp, unsigned long size)
 864{
 865        /*
 866         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 867         */
 868        int cnt = 0;
 869        char ch;
 870
 871        while (size) {
 872                ch = *cp++;
 873                size--;
 874                if (ch != '$')
 875                        continue;
 876                if (size < 3)
 877                        break;
 878                if (memcmp("Id", cp, 2))
 879                        continue;
 880                ch = cp[2];
 881                cp += 3;
 882                size -= 3;
 883                if (ch == '$')
 884                        cnt++; /* $Id$ */
 885                if (ch != ':')
 886                        continue;
 887
 888                /*
 889                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 890                 */
 891                while (size) {
 892                        ch = *cp++;
 893                        size--;
 894                        if (ch == '$') {
 895                                cnt++;
 896                                break;
 897                        }
 898                        if (ch == '\n')
 899                                break;
 900                }
 901        }
 902        return cnt;
 903}
 904
 905static int ident_to_git(const char *path, const char *src, size_t len,
 906                        struct strbuf *buf, int ident)
 907{
 908        char *dst, *dollar;
 909
 910        if (!ident || (src && !count_ident(src, len)))
 911                return 0;
 912
 913        if (!buf)
 914                return 1;
 915
 916        /* only grow if not in place */
 917        if (strbuf_avail(buf) + buf->len < len)
 918                strbuf_grow(buf, len - buf->len);
 919        dst = buf->buf;
 920        for (;;) {
 921                dollar = memchr(src, '$', len);
 922                if (!dollar)
 923                        break;
 924                memmove(dst, src, dollar + 1 - src);
 925                dst += dollar + 1 - src;
 926                len -= dollar + 1 - src;
 927                src  = dollar + 1;
 928
 929                if (len > 3 && !memcmp(src, "Id:", 3)) {
 930                        dollar = memchr(src + 3, '$', len - 3);
 931                        if (!dollar)
 932                                break;
 933                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 934                                /* Line break before the next dollar. */
 935                                continue;
 936                        }
 937
 938                        memcpy(dst, "Id$", 3);
 939                        dst += 3;
 940                        len -= dollar + 1 - src;
 941                        src  = dollar + 1;
 942                }
 943        }
 944        memmove(dst, src, len);
 945        strbuf_setlen(buf, dst + len - buf->buf);
 946        return 1;
 947}
 948
 949static int ident_to_worktree(const char *path, const char *src, size_t len,
 950                             struct strbuf *buf, int ident)
 951{
 952        unsigned char sha1[20];
 953        char *to_free = NULL, *dollar, *spc;
 954        int cnt;
 955
 956        if (!ident)
 957                return 0;
 958
 959        cnt = count_ident(src, len);
 960        if (!cnt)
 961                return 0;
 962
 963        /* are we "faking" in place editing ? */
 964        if (src == buf->buf)
 965                to_free = strbuf_detach(buf, NULL);
 966        hash_sha1_file(src, len, "blob", sha1);
 967
 968        strbuf_grow(buf, len + cnt * 43);
 969        for (;;) {
 970                /* step 1: run to the next '$' */
 971                dollar = memchr(src, '$', len);
 972                if (!dollar)
 973                        break;
 974                strbuf_add(buf, src, dollar + 1 - src);
 975                len -= dollar + 1 - src;
 976                src  = dollar + 1;
 977
 978                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 979                if (len < 3 || memcmp("Id", src, 2))
 980                        continue;
 981
 982                /* step 3: skip over Id$ or Id:xxxxx$ */
 983                if (src[2] == '$') {
 984                        src += 3;
 985                        len -= 3;
 986                } else if (src[2] == ':') {
 987                        /*
 988                         * It's possible that an expanded Id has crept its way into the
 989                         * repository, we cope with that by stripping the expansion out.
 990                         * This is probably not a good idea, since it will cause changes
 991                         * on checkout, which won't go away by stash, but let's keep it
 992                         * for git-style ids.
 993                         */
 994                        dollar = memchr(src + 3, '$', len - 3);
 995                        if (!dollar) {
 996                                /* incomplete keyword, no more '$', so just quit the loop */
 997                                break;
 998                        }
 999
1000                        if (memchr(src + 3, '\n', dollar - src - 3)) {
1001                                /* Line break before the next dollar. */
1002                                continue;
1003                        }
1004
1005                        spc = memchr(src + 4, ' ', dollar - src - 4);
1006                        if (spc && spc < dollar-1) {
1007                                /* There are spaces in unexpected places.
1008                                 * This is probably an id from some other
1009                                 * versioning system. Keep it for now.
1010                                 */
1011                                continue;
1012                        }
1013
1014                        len -= dollar + 1 - src;
1015                        src  = dollar + 1;
1016                } else {
1017                        /* it wasn't a "Id$" or "Id:xxxx$" */
1018                        continue;
1019                }
1020
1021                /* step 4: substitute */
1022                strbuf_addstr(buf, "Id: ");
1023                strbuf_add(buf, sha1_to_hex(sha1), 40);
1024                strbuf_addstr(buf, " $");
1025        }
1026        strbuf_add(buf, src, len);
1027
1028        free(to_free);
1029        return 1;
1030}
1031
1032static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
1033{
1034        const char *value = check->value;
1035
1036        if (ATTR_TRUE(value))
1037                return CRLF_TEXT;
1038        else if (ATTR_FALSE(value))
1039                return CRLF_BINARY;
1040        else if (ATTR_UNSET(value))
1041                ;
1042        else if (!strcmp(value, "input"))
1043                return CRLF_TEXT_INPUT;
1044        else if (!strcmp(value, "auto"))
1045                return CRLF_AUTO;
1046        return CRLF_UNDEFINED;
1047}
1048
1049static enum eol git_path_check_eol(struct attr_check_item *check)
1050{
1051        const char *value = check->value;
1052
1053        if (ATTR_UNSET(value))
1054                ;
1055        else if (!strcmp(value, "lf"))
1056                return EOL_LF;
1057        else if (!strcmp(value, "crlf"))
1058                return EOL_CRLF;
1059        return EOL_UNSET;
1060}
1061
1062static struct convert_driver *git_path_check_convert(struct attr_check_item *check)
1063{
1064        const char *value = check->value;
1065        struct convert_driver *drv;
1066
1067        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1068                return NULL;
1069        for (drv = user_convert; drv; drv = drv->next)
1070                if (!strcmp(value, drv->name))
1071                        return drv;
1072        return NULL;
1073}
1074
1075static int git_path_check_ident(struct attr_check_item *check)
1076{
1077        const char *value = check->value;
1078
1079        return !!ATTR_TRUE(value);
1080}
1081
1082struct conv_attrs {
1083        struct convert_driver *drv;
1084        enum crlf_action attr_action; /* What attr says */
1085        enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
1086        int ident;
1087};
1088
1089static void convert_attrs(struct conv_attrs *ca, const char *path)
1090{
1091        static struct attr_check *check;
1092
1093        if (!check) {
1094                check = attr_check_initl("crlf", "ident", "filter",
1095                                         "eol", "text", NULL);
1096                user_convert_tail = &user_convert;
1097                git_config(read_convert_config, NULL);
1098        }
1099
1100        if (!git_check_attr(path, check)) {
1101                struct attr_check_item *ccheck = check->items;
1102                ca->crlf_action = git_path_check_crlf(ccheck + 4);
1103                if (ca->crlf_action == CRLF_UNDEFINED)
1104                        ca->crlf_action = git_path_check_crlf(ccheck + 0);
1105                ca->attr_action = ca->crlf_action;
1106                ca->ident = git_path_check_ident(ccheck + 1);
1107                ca->drv = git_path_check_convert(ccheck + 2);
1108                if (ca->crlf_action != CRLF_BINARY) {
1109                        enum eol eol_attr = git_path_check_eol(ccheck + 3);
1110                        if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
1111                                ca->crlf_action = CRLF_AUTO_INPUT;
1112                        else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
1113                                ca->crlf_action = CRLF_AUTO_CRLF;
1114                        else if (eol_attr == EOL_LF)
1115                                ca->crlf_action = CRLF_TEXT_INPUT;
1116                        else if (eol_attr == EOL_CRLF)
1117                                ca->crlf_action = CRLF_TEXT_CRLF;
1118                }
1119                ca->attr_action = ca->crlf_action;
1120        } else {
1121                ca->drv = NULL;
1122                ca->crlf_action = CRLF_UNDEFINED;
1123                ca->ident = 0;
1124        }
1125        if (ca->crlf_action == CRLF_TEXT)
1126                ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
1127        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
1128                ca->crlf_action = CRLF_BINARY;
1129        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
1130                ca->crlf_action = CRLF_AUTO_CRLF;
1131        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
1132                ca->crlf_action = CRLF_AUTO_INPUT;
1133}
1134
1135int would_convert_to_git_filter_fd(const char *path)
1136{
1137        struct conv_attrs ca;
1138
1139        convert_attrs(&ca, path);
1140        if (!ca.drv)
1141                return 0;
1142
1143        /*
1144         * Apply a filter to an fd only if the filter is required to succeed.
1145         * We must die if the filter fails, because the original data before
1146         * filtering is not available.
1147         */
1148        if (!ca.drv->required)
1149                return 0;
1150
1151        return apply_filter(path, NULL, 0, -1, NULL, ca.drv, CAP_CLEAN);
1152}
1153
1154const char *get_convert_attr_ascii(const char *path)
1155{
1156        struct conv_attrs ca;
1157
1158        convert_attrs(&ca, path);
1159        switch (ca.attr_action) {
1160        case CRLF_UNDEFINED:
1161                return "";
1162        case CRLF_BINARY:
1163                return "-text";
1164        case CRLF_TEXT:
1165                return "text";
1166        case CRLF_TEXT_INPUT:
1167                return "text eol=lf";
1168        case CRLF_TEXT_CRLF:
1169                return "text eol=crlf";
1170        case CRLF_AUTO:
1171                return "text=auto";
1172        case CRLF_AUTO_CRLF:
1173                return "text=auto eol=crlf";
1174        case CRLF_AUTO_INPUT:
1175                return "text=auto eol=lf";
1176        }
1177        return "";
1178}
1179
1180int convert_to_git(const char *path, const char *src, size_t len,
1181                   struct strbuf *dst, enum safe_crlf checksafe)
1182{
1183        int ret = 0;
1184        struct conv_attrs ca;
1185
1186        convert_attrs(&ca, path);
1187
1188        ret |= apply_filter(path, src, len, -1, dst, ca.drv, CAP_CLEAN);
1189        if (!ret && ca.drv && ca.drv->required)
1190                die("%s: clean filter '%s' failed", path, ca.drv->name);
1191
1192        if (ret && dst) {
1193                src = dst->buf;
1194                len = dst->len;
1195        }
1196        ret |= crlf_to_git(path, src, len, dst, ca.crlf_action, checksafe);
1197        if (ret && dst) {
1198                src = dst->buf;
1199                len = dst->len;
1200        }
1201        return ret | ident_to_git(path, src, len, dst, ca.ident);
1202}
1203
1204void convert_to_git_filter_fd(const char *path, int fd, struct strbuf *dst,
1205                              enum safe_crlf checksafe)
1206{
1207        struct conv_attrs ca;
1208        convert_attrs(&ca, path);
1209
1210        assert(ca.drv);
1211        assert(ca.drv->clean || ca.drv->process);
1212
1213        if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN))
1214                die("%s: clean filter '%s' failed", path, ca.drv->name);
1215
1216        crlf_to_git(path, dst->buf, dst->len, dst, ca.crlf_action, checksafe);
1217        ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
1218}
1219
1220static int convert_to_working_tree_internal(const char *path, const char *src,
1221                                            size_t len, struct strbuf *dst,
1222                                            int normalizing)
1223{
1224        int ret = 0, ret_filter = 0;
1225        struct conv_attrs ca;
1226
1227        convert_attrs(&ca, path);
1228
1229        ret |= ident_to_worktree(path, src, len, dst, ca.ident);
1230        if (ret) {
1231                src = dst->buf;
1232                len = dst->len;
1233        }
1234        /*
1235         * CRLF conversion can be skipped if normalizing, unless there
1236         * is a smudge or process filter (even if the process filter doesn't
1237         * support smudge).  The filters might expect CRLFs.
1238         */
1239        if ((ca.drv && (ca.drv->smudge || ca.drv->process)) || !normalizing) {
1240                ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
1241                if (ret) {
1242                        src = dst->buf;
1243                        len = dst->len;
1244                }
1245        }
1246
1247        ret_filter = apply_filter(path, src, len, -1, dst, ca.drv, CAP_SMUDGE);
1248        if (!ret_filter && ca.drv && ca.drv->required)
1249                die("%s: smudge filter %s failed", path, ca.drv->name);
1250
1251        return ret | ret_filter;
1252}
1253
1254int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
1255{
1256        return convert_to_working_tree_internal(path, src, len, dst, 0);
1257}
1258
1259int renormalize_buffer(const char *path, const char *src, size_t len, struct strbuf *dst)
1260{
1261        int ret = convert_to_working_tree_internal(path, src, len, dst, 1);
1262        if (ret) {
1263                src = dst->buf;
1264                len = dst->len;
1265        }
1266        return ret | convert_to_git(path, src, len, dst, SAFE_CRLF_RENORMALIZE);
1267}
1268
1269/*****************************************************************
1270 *
1271 * Streaming conversion support
1272 *
1273 *****************************************************************/
1274
1275typedef int (*filter_fn)(struct stream_filter *,
1276                         const char *input, size_t *isize_p,
1277                         char *output, size_t *osize_p);
1278typedef void (*free_fn)(struct stream_filter *);
1279
1280struct stream_filter_vtbl {
1281        filter_fn filter;
1282        free_fn free;
1283};
1284
1285struct stream_filter {
1286        struct stream_filter_vtbl *vtbl;
1287};
1288
1289static int null_filter_fn(struct stream_filter *filter,
1290                          const char *input, size_t *isize_p,
1291                          char *output, size_t *osize_p)
1292{
1293        size_t count;
1294
1295        if (!input)
1296                return 0; /* we do not keep any states */
1297        count = *isize_p;
1298        if (*osize_p < count)
1299                count = *osize_p;
1300        if (count) {
1301                memmove(output, input, count);
1302                *isize_p -= count;
1303                *osize_p -= count;
1304        }
1305        return 0;
1306}
1307
1308static void null_free_fn(struct stream_filter *filter)
1309{
1310        ; /* nothing -- null instances are shared */
1311}
1312
1313static struct stream_filter_vtbl null_vtbl = {
1314        null_filter_fn,
1315        null_free_fn,
1316};
1317
1318static struct stream_filter null_filter_singleton = {
1319        &null_vtbl,
1320};
1321
1322int is_null_stream_filter(struct stream_filter *filter)
1323{
1324        return filter == &null_filter_singleton;
1325}
1326
1327
1328/*
1329 * LF-to-CRLF filter
1330 */
1331
1332struct lf_to_crlf_filter {
1333        struct stream_filter filter;
1334        unsigned has_held:1;
1335        char held;
1336};
1337
1338static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1339                                const char *input, size_t *isize_p,
1340                                char *output, size_t *osize_p)
1341{
1342        size_t count, o = 0;
1343        struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1344
1345        /*
1346         * We may be holding onto the CR to see if it is followed by a
1347         * LF, in which case we would need to go to the main loop.
1348         * Otherwise, just emit it to the output stream.
1349         */
1350        if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1351                output[o++] = lf_to_crlf->held;
1352                lf_to_crlf->has_held = 0;
1353        }
1354
1355        /* We are told to drain */
1356        if (!input) {
1357                *osize_p -= o;
1358                return 0;
1359        }
1360
1361        count = *isize_p;
1362        if (count || lf_to_crlf->has_held) {
1363                size_t i;
1364                int was_cr = 0;
1365
1366                if (lf_to_crlf->has_held) {
1367                        was_cr = 1;
1368                        lf_to_crlf->has_held = 0;
1369                }
1370
1371                for (i = 0; o < *osize_p && i < count; i++) {
1372                        char ch = input[i];
1373
1374                        if (ch == '\n') {
1375                                output[o++] = '\r';
1376                        } else if (was_cr) {
1377                                /*
1378                                 * Previous round saw CR and it is not followed
1379                                 * by a LF; emit the CR before processing the
1380                                 * current character.
1381                                 */
1382                                output[o++] = '\r';
1383                        }
1384
1385                        /*
1386                         * We may have consumed the last output slot,
1387                         * in which case we need to break out of this
1388                         * loop; hold the current character before
1389                         * returning.
1390                         */
1391                        if (*osize_p <= o) {
1392                                lf_to_crlf->has_held = 1;
1393                                lf_to_crlf->held = ch;
1394                                continue; /* break but increment i */
1395                        }
1396
1397                        if (ch == '\r') {
1398                                was_cr = 1;
1399                                continue;
1400                        }
1401
1402                        was_cr = 0;
1403                        output[o++] = ch;
1404                }
1405
1406                *osize_p -= o;
1407                *isize_p -= i;
1408
1409                if (!lf_to_crlf->has_held && was_cr) {
1410                        lf_to_crlf->has_held = 1;
1411                        lf_to_crlf->held = '\r';
1412                }
1413        }
1414        return 0;
1415}
1416
1417static void lf_to_crlf_free_fn(struct stream_filter *filter)
1418{
1419        free(filter);
1420}
1421
1422static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1423        lf_to_crlf_filter_fn,
1424        lf_to_crlf_free_fn,
1425};
1426
1427static struct stream_filter *lf_to_crlf_filter(void)
1428{
1429        struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1430
1431        lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1432        return (struct stream_filter *)lf_to_crlf;
1433}
1434
1435/*
1436 * Cascade filter
1437 */
1438#define FILTER_BUFFER 1024
1439struct cascade_filter {
1440        struct stream_filter filter;
1441        struct stream_filter *one;
1442        struct stream_filter *two;
1443        char buf[FILTER_BUFFER];
1444        int end, ptr;
1445};
1446
1447static int cascade_filter_fn(struct stream_filter *filter,
1448                             const char *input, size_t *isize_p,
1449                             char *output, size_t *osize_p)
1450{
1451        struct cascade_filter *cas = (struct cascade_filter *) filter;
1452        size_t filled = 0;
1453        size_t sz = *osize_p;
1454        size_t to_feed, remaining;
1455
1456        /*
1457         * input -- (one) --> buf -- (two) --> output
1458         */
1459        while (filled < sz) {
1460                remaining = sz - filled;
1461
1462                /* do we already have something to feed two with? */
1463                if (cas->ptr < cas->end) {
1464                        to_feed = cas->end - cas->ptr;
1465                        if (stream_filter(cas->two,
1466                                          cas->buf + cas->ptr, &to_feed,
1467                                          output + filled, &remaining))
1468                                return -1;
1469                        cas->ptr += (cas->end - cas->ptr) - to_feed;
1470                        filled = sz - remaining;
1471                        continue;
1472                }
1473
1474                /* feed one from upstream and have it emit into our buffer */
1475                to_feed = input ? *isize_p : 0;
1476                if (input && !to_feed)
1477                        break;
1478                remaining = sizeof(cas->buf);
1479                if (stream_filter(cas->one,
1480                                  input, &to_feed,
1481                                  cas->buf, &remaining))
1482                        return -1;
1483                cas->end = sizeof(cas->buf) - remaining;
1484                cas->ptr = 0;
1485                if (input) {
1486                        size_t fed = *isize_p - to_feed;
1487                        *isize_p -= fed;
1488                        input += fed;
1489                }
1490
1491                /* do we know that we drained one completely? */
1492                if (input || cas->end)
1493                        continue;
1494
1495                /* tell two to drain; we have nothing more to give it */
1496                to_feed = 0;
1497                remaining = sz - filled;
1498                if (stream_filter(cas->two,
1499                                  NULL, &to_feed,
1500                                  output + filled, &remaining))
1501                        return -1;
1502                if (remaining == (sz - filled))
1503                        break; /* completely drained two */
1504                filled = sz - remaining;
1505        }
1506        *osize_p -= filled;
1507        return 0;
1508}
1509
1510static void cascade_free_fn(struct stream_filter *filter)
1511{
1512        struct cascade_filter *cas = (struct cascade_filter *)filter;
1513        free_stream_filter(cas->one);
1514        free_stream_filter(cas->two);
1515        free(filter);
1516}
1517
1518static struct stream_filter_vtbl cascade_vtbl = {
1519        cascade_filter_fn,
1520        cascade_free_fn,
1521};
1522
1523static struct stream_filter *cascade_filter(struct stream_filter *one,
1524                                            struct stream_filter *two)
1525{
1526        struct cascade_filter *cascade;
1527
1528        if (!one || is_null_stream_filter(one))
1529                return two;
1530        if (!two || is_null_stream_filter(two))
1531                return one;
1532
1533        cascade = xmalloc(sizeof(*cascade));
1534        cascade->one = one;
1535        cascade->two = two;
1536        cascade->end = cascade->ptr = 0;
1537        cascade->filter.vtbl = &cascade_vtbl;
1538        return (struct stream_filter *)cascade;
1539}
1540
1541/*
1542 * ident filter
1543 */
1544#define IDENT_DRAINING (-1)
1545#define IDENT_SKIPPING (-2)
1546struct ident_filter {
1547        struct stream_filter filter;
1548        struct strbuf left;
1549        int state;
1550        char ident[45]; /* ": x40 $" */
1551};
1552
1553static int is_foreign_ident(const char *str)
1554{
1555        int i;
1556
1557        if (!skip_prefix(str, "$Id: ", &str))
1558                return 0;
1559        for (i = 0; str[i]; i++) {
1560                if (isspace(str[i]) && str[i+1] != '$')
1561                        return 1;
1562        }
1563        return 0;
1564}
1565
1566static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1567{
1568        size_t to_drain = ident->left.len;
1569
1570        if (*osize_p < to_drain)
1571                to_drain = *osize_p;
1572        if (to_drain) {
1573                memcpy(*output_p, ident->left.buf, to_drain);
1574                strbuf_remove(&ident->left, 0, to_drain);
1575                *output_p += to_drain;
1576                *osize_p -= to_drain;
1577        }
1578        if (!ident->left.len)
1579                ident->state = 0;
1580}
1581
1582static int ident_filter_fn(struct stream_filter *filter,
1583                           const char *input, size_t *isize_p,
1584                           char *output, size_t *osize_p)
1585{
1586        struct ident_filter *ident = (struct ident_filter *)filter;
1587        static const char head[] = "$Id";
1588
1589        if (!input) {
1590                /* drain upon eof */
1591                switch (ident->state) {
1592                default:
1593                        strbuf_add(&ident->left, head, ident->state);
1594                case IDENT_SKIPPING:
1595                        /* fallthru */
1596                case IDENT_DRAINING:
1597                        ident_drain(ident, &output, osize_p);
1598                }
1599                return 0;
1600        }
1601
1602        while (*isize_p || (ident->state == IDENT_DRAINING)) {
1603                int ch;
1604
1605                if (ident->state == IDENT_DRAINING) {
1606                        ident_drain(ident, &output, osize_p);
1607                        if (!*osize_p)
1608                                break;
1609                        continue;
1610                }
1611
1612                ch = *(input++);
1613                (*isize_p)--;
1614
1615                if (ident->state == IDENT_SKIPPING) {
1616                        /*
1617                         * Skipping until '$' or LF, but keeping them
1618                         * in case it is a foreign ident.
1619                         */
1620                        strbuf_addch(&ident->left, ch);
1621                        if (ch != '\n' && ch != '$')
1622                                continue;
1623                        if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1624                                strbuf_setlen(&ident->left, sizeof(head) - 1);
1625                                strbuf_addstr(&ident->left, ident->ident);
1626                        }
1627                        ident->state = IDENT_DRAINING;
1628                        continue;
1629                }
1630
1631                if (ident->state < sizeof(head) &&
1632                    head[ident->state] == ch) {
1633                        ident->state++;
1634                        continue;
1635                }
1636
1637                if (ident->state)
1638                        strbuf_add(&ident->left, head, ident->state);
1639                if (ident->state == sizeof(head) - 1) {
1640                        if (ch != ':' && ch != '$') {
1641                                strbuf_addch(&ident->left, ch);
1642                                ident->state = 0;
1643                                continue;
1644                        }
1645
1646                        if (ch == ':') {
1647                                strbuf_addch(&ident->left, ch);
1648                                ident->state = IDENT_SKIPPING;
1649                        } else {
1650                                strbuf_addstr(&ident->left, ident->ident);
1651                                ident->state = IDENT_DRAINING;
1652                        }
1653                        continue;
1654                }
1655
1656                strbuf_addch(&ident->left, ch);
1657                ident->state = IDENT_DRAINING;
1658        }
1659        return 0;
1660}
1661
1662static void ident_free_fn(struct stream_filter *filter)
1663{
1664        struct ident_filter *ident = (struct ident_filter *)filter;
1665        strbuf_release(&ident->left);
1666        free(filter);
1667}
1668
1669static struct stream_filter_vtbl ident_vtbl = {
1670        ident_filter_fn,
1671        ident_free_fn,
1672};
1673
1674static struct stream_filter *ident_filter(const unsigned char *sha1)
1675{
1676        struct ident_filter *ident = xmalloc(sizeof(*ident));
1677
1678        xsnprintf(ident->ident, sizeof(ident->ident),
1679                  ": %s $", sha1_to_hex(sha1));
1680        strbuf_init(&ident->left, 0);
1681        ident->filter.vtbl = &ident_vtbl;
1682        ident->state = 0;
1683        return (struct stream_filter *)ident;
1684}
1685
1686/*
1687 * Return an appropriately constructed filter for the path, or NULL if
1688 * the contents cannot be filtered without reading the whole thing
1689 * in-core.
1690 *
1691 * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1692 * large binary blob you would want us not to slurp into the memory!
1693 */
1694struct stream_filter *get_stream_filter(const char *path, const unsigned char *sha1)
1695{
1696        struct conv_attrs ca;
1697        struct stream_filter *filter = NULL;
1698
1699        convert_attrs(&ca, path);
1700        if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
1701                return NULL;
1702
1703        if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1704                return NULL;
1705
1706        if (ca.ident)
1707                filter = ident_filter(sha1);
1708
1709        if (output_eol(ca.crlf_action) == EOL_CRLF)
1710                filter = cascade_filter(filter, lf_to_crlf_filter());
1711        else
1712                filter = cascade_filter(filter, &null_filter_singleton);
1713
1714        return filter;
1715}
1716
1717void free_stream_filter(struct stream_filter *filter)
1718{
1719        filter->vtbl->free(filter);
1720}
1721
1722int stream_filter(struct stream_filter *filter,
1723                  const char *input, size_t *isize_p,
1724                  char *output, size_t *osize_p)
1725{
1726        return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1727}