convert.con commit Merge branch 'es/worktree-docs' (6b747fc)
   1#define NO_THE_INDEX_COMPATIBILITY_MACROS
   2#include "cache.h"
   3#include "config.h"
   4#include "attr.h"
   5#include "run-command.h"
   6#include "quote.h"
   7#include "sigchain.h"
   8#include "pkt-line.h"
   9#include "sub-process.h"
  10
  11/*
  12 * convert.c - convert a file when checking it out and checking it in.
  13 *
  14 * This should use the pathname to decide on whether it wants to do some
  15 * more interesting conversions (automatic gzip/unzip, general format
  16 * conversions etc etc), but by default it just does automatic CRLF<->LF
  17 * translation when the "text" attribute or "auto_crlf" option is set.
  18 */
  19
  20/* Stat bits: When BIN is set, the txt bits are unset */
  21#define CONVERT_STAT_BITS_TXT_LF    0x1
  22#define CONVERT_STAT_BITS_TXT_CRLF  0x2
  23#define CONVERT_STAT_BITS_BIN       0x4
  24
  25enum crlf_action {
  26        CRLF_UNDEFINED,
  27        CRLF_BINARY,
  28        CRLF_TEXT,
  29        CRLF_TEXT_INPUT,
  30        CRLF_TEXT_CRLF,
  31        CRLF_AUTO,
  32        CRLF_AUTO_INPUT,
  33        CRLF_AUTO_CRLF
  34};
  35
  36struct text_stat {
  37        /* NUL, CR, LF and CRLF counts */
  38        unsigned nul, lonecr, lonelf, crlf;
  39
  40        /* These are just approximations! */
  41        unsigned printable, nonprintable;
  42};
  43
  44static void gather_stats(const char *buf, unsigned long size, struct text_stat *stats)
  45{
  46        unsigned long i;
  47
  48        memset(stats, 0, sizeof(*stats));
  49
  50        for (i = 0; i < size; i++) {
  51                unsigned char c = buf[i];
  52                if (c == '\r') {
  53                        if (i+1 < size && buf[i+1] == '\n') {
  54                                stats->crlf++;
  55                                i++;
  56                        } else
  57                                stats->lonecr++;
  58                        continue;
  59                }
  60                if (c == '\n') {
  61                        stats->lonelf++;
  62                        continue;
  63                }
  64                if (c == 127)
  65                        /* DEL */
  66                        stats->nonprintable++;
  67                else if (c < 32) {
  68                        switch (c) {
  69                                /* BS, HT, ESC and FF */
  70                        case '\b': case '\t': case '\033': case '\014':
  71                                stats->printable++;
  72                                break;
  73                        case 0:
  74                                stats->nul++;
  75                                /* fall through */
  76                        default:
  77                                stats->nonprintable++;
  78                        }
  79                }
  80                else
  81                        stats->printable++;
  82        }
  83
  84        /* If file ends with EOF then don't count this EOF as non-printable. */
  85        if (size >= 1 && buf[size-1] == '\032')
  86                stats->nonprintable--;
  87}
  88
  89/*
  90 * The same heuristics as diff.c::mmfile_is_binary()
  91 * We treat files with bare CR as binary
  92 */
  93static int convert_is_binary(unsigned long size, const struct text_stat *stats)
  94{
  95        if (stats->lonecr)
  96                return 1;
  97        if (stats->nul)
  98                return 1;
  99        if ((stats->printable >> 7) < stats->nonprintable)
 100                return 1;
 101        return 0;
 102}
 103
 104static unsigned int gather_convert_stats(const char *data, unsigned long size)
 105{
 106        struct text_stat stats;
 107        int ret = 0;
 108        if (!data || !size)
 109                return 0;
 110        gather_stats(data, size, &stats);
 111        if (convert_is_binary(size, &stats))
 112                ret |= CONVERT_STAT_BITS_BIN;
 113        if (stats.crlf)
 114                ret |= CONVERT_STAT_BITS_TXT_CRLF;
 115        if (stats.lonelf)
 116                ret |=  CONVERT_STAT_BITS_TXT_LF;
 117
 118        return ret;
 119}
 120
 121static const char *gather_convert_stats_ascii(const char *data, unsigned long size)
 122{
 123        unsigned int convert_stats = gather_convert_stats(data, size);
 124
 125        if (convert_stats & CONVERT_STAT_BITS_BIN)
 126                return "-text";
 127        switch (convert_stats) {
 128        case CONVERT_STAT_BITS_TXT_LF:
 129                return "lf";
 130        case CONVERT_STAT_BITS_TXT_CRLF:
 131                return "crlf";
 132        case CONVERT_STAT_BITS_TXT_LF | CONVERT_STAT_BITS_TXT_CRLF:
 133                return "mixed";
 134        default:
 135                return "none";
 136        }
 137}
 138
 139const char *get_cached_convert_stats_ascii(const struct index_state *istate,
 140                                           const char *path)
 141{
 142        const char *ret;
 143        unsigned long sz;
 144        void *data = read_blob_data_from_index(istate, path, &sz);
 145        ret = gather_convert_stats_ascii(data, sz);
 146        free(data);
 147        return ret;
 148}
 149
 150const char *get_wt_convert_stats_ascii(const char *path)
 151{
 152        const char *ret = "";
 153        struct strbuf sb = STRBUF_INIT;
 154        if (strbuf_read_file(&sb, path, 0) >= 0)
 155                ret = gather_convert_stats_ascii(sb.buf, sb.len);
 156        strbuf_release(&sb);
 157        return ret;
 158}
 159
 160static int text_eol_is_crlf(void)
 161{
 162        if (auto_crlf == AUTO_CRLF_TRUE)
 163                return 1;
 164        else if (auto_crlf == AUTO_CRLF_INPUT)
 165                return 0;
 166        if (core_eol == EOL_CRLF)
 167                return 1;
 168        if (core_eol == EOL_UNSET && EOL_NATIVE == EOL_CRLF)
 169                return 1;
 170        return 0;
 171}
 172
 173static enum eol output_eol(enum crlf_action crlf_action)
 174{
 175        switch (crlf_action) {
 176        case CRLF_BINARY:
 177                return EOL_UNSET;
 178        case CRLF_TEXT_CRLF:
 179                return EOL_CRLF;
 180        case CRLF_TEXT_INPUT:
 181                return EOL_LF;
 182        case CRLF_UNDEFINED:
 183        case CRLF_AUTO_CRLF:
 184                return EOL_CRLF;
 185        case CRLF_AUTO_INPUT:
 186                return EOL_LF;
 187        case CRLF_TEXT:
 188        case CRLF_AUTO:
 189                /* fall through */
 190                return text_eol_is_crlf() ? EOL_CRLF : EOL_LF;
 191        }
 192        warning("Illegal crlf_action %d\n", (int)crlf_action);
 193        return core_eol;
 194}
 195
 196static void check_global_conv_flags_eol(const char *path, enum crlf_action crlf_action,
 197                            struct text_stat *old_stats, struct text_stat *new_stats,
 198                            int conv_flags)
 199{
 200        if (old_stats->crlf && !new_stats->crlf ) {
 201                /*
 202                 * CRLFs would not be restored by checkout
 203                 */
 204                if (conv_flags & CONV_EOL_RNDTRP_DIE)
 205                        die(_("CRLF would be replaced by LF in %s."), path);
 206                else if (conv_flags & CONV_EOL_RNDTRP_WARN)
 207                        warning(_("CRLF will be replaced by LF in %s.\n"
 208                                  "The file will have its original line"
 209                                  " endings in your working directory."), path);
 210        } else if (old_stats->lonelf && !new_stats->lonelf ) {
 211                /*
 212                 * CRLFs would be added by checkout
 213                 */
 214                if (conv_flags & CONV_EOL_RNDTRP_DIE)
 215                        die(_("LF would be replaced by CRLF in %s"), path);
 216                else if (conv_flags & CONV_EOL_RNDTRP_WARN)
 217                        warning(_("LF will be replaced by CRLF in %s.\n"
 218                                  "The file will have its original line"
 219                                  " endings in your working directory."), path);
 220        }
 221}
 222
 223static int has_crlf_in_index(const struct index_state *istate, const char *path)
 224{
 225        unsigned long sz;
 226        void *data;
 227        const char *crp;
 228        int has_crlf = 0;
 229
 230        data = read_blob_data_from_index(istate, path, &sz);
 231        if (!data)
 232                return 0;
 233
 234        crp = memchr(data, '\r', sz);
 235        if (crp) {
 236                unsigned int ret_stats;
 237                ret_stats = gather_convert_stats(data, sz);
 238                if (!(ret_stats & CONVERT_STAT_BITS_BIN) &&
 239                    (ret_stats & CONVERT_STAT_BITS_TXT_CRLF))
 240                        has_crlf = 1;
 241        }
 242        free(data);
 243        return has_crlf;
 244}
 245
 246static int will_convert_lf_to_crlf(size_t len, struct text_stat *stats,
 247                                   enum crlf_action crlf_action)
 248{
 249        if (output_eol(crlf_action) != EOL_CRLF)
 250                return 0;
 251        /* No "naked" LF? Nothing to convert, regardless. */
 252        if (!stats->lonelf)
 253                return 0;
 254
 255        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 256                /* If we have any CR or CRLF line endings, we do not touch it */
 257                /* This is the new safer autocrlf-handling */
 258                if (stats->lonecr || stats->crlf)
 259                        return 0;
 260
 261                if (convert_is_binary(len, stats))
 262                        return 0;
 263        }
 264        return 1;
 265
 266}
 267
 268static int crlf_to_git(const struct index_state *istate,
 269                       const char *path, const char *src, size_t len,
 270                       struct strbuf *buf,
 271                       enum crlf_action crlf_action, int conv_flags)
 272{
 273        struct text_stat stats;
 274        char *dst;
 275        int convert_crlf_into_lf;
 276
 277        if (crlf_action == CRLF_BINARY ||
 278            (src && !len))
 279                return 0;
 280
 281        /*
 282         * If we are doing a dry-run and have no source buffer, there is
 283         * nothing to analyze; we must assume we would convert.
 284         */
 285        if (!buf && !src)
 286                return 1;
 287
 288        gather_stats(src, len, &stats);
 289        /* Optimization: No CRLF? Nothing to convert, regardless. */
 290        convert_crlf_into_lf = !!stats.crlf;
 291
 292        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 293                if (convert_is_binary(len, &stats))
 294                        return 0;
 295                /*
 296                 * If the file in the index has any CR in it, do not
 297                 * convert.  This is the new safer autocrlf handling,
 298                 * unless we want to renormalize in a merge or
 299                 * cherry-pick.
 300                 */
 301                if ((!(conv_flags & CONV_EOL_RENORMALIZE)) &&
 302                    has_crlf_in_index(istate, path))
 303                        convert_crlf_into_lf = 0;
 304        }
 305        if (((conv_flags & CONV_EOL_RNDTRP_WARN) ||
 306             ((conv_flags & CONV_EOL_RNDTRP_DIE) && len))) {
 307                struct text_stat new_stats;
 308                memcpy(&new_stats, &stats, sizeof(new_stats));
 309                /* simulate "git add" */
 310                if (convert_crlf_into_lf) {
 311                        new_stats.lonelf += new_stats.crlf;
 312                        new_stats.crlf = 0;
 313                }
 314                /* simulate "git checkout" */
 315                if (will_convert_lf_to_crlf(len, &new_stats, crlf_action)) {
 316                        new_stats.crlf += new_stats.lonelf;
 317                        new_stats.lonelf = 0;
 318                }
 319                check_global_conv_flags_eol(path, crlf_action, &stats, &new_stats, conv_flags);
 320        }
 321        if (!convert_crlf_into_lf)
 322                return 0;
 323
 324        /*
 325         * At this point all of our source analysis is done, and we are sure we
 326         * would convert. If we are in dry-run mode, we can give an answer.
 327         */
 328        if (!buf)
 329                return 1;
 330
 331        /* only grow if not in place */
 332        if (strbuf_avail(buf) + buf->len < len)
 333                strbuf_grow(buf, len - buf->len);
 334        dst = buf->buf;
 335        if (crlf_action == CRLF_AUTO || crlf_action == CRLF_AUTO_INPUT || crlf_action == CRLF_AUTO_CRLF) {
 336                /*
 337                 * If we guessed, we already know we rejected a file with
 338                 * lone CR, and we can strip a CR without looking at what
 339                 * follow it.
 340                 */
 341                do {
 342                        unsigned char c = *src++;
 343                        if (c != '\r')
 344                                *dst++ = c;
 345                } while (--len);
 346        } else {
 347                do {
 348                        unsigned char c = *src++;
 349                        if (! (c == '\r' && (1 < len && *src == '\n')))
 350                                *dst++ = c;
 351                } while (--len);
 352        }
 353        strbuf_setlen(buf, dst - buf->buf);
 354        return 1;
 355}
 356
 357static int crlf_to_worktree(const char *path, const char *src, size_t len,
 358                            struct strbuf *buf, enum crlf_action crlf_action)
 359{
 360        char *to_free = NULL;
 361        struct text_stat stats;
 362
 363        if (!len || output_eol(crlf_action) != EOL_CRLF)
 364                return 0;
 365
 366        gather_stats(src, len, &stats);
 367        if (!will_convert_lf_to_crlf(len, &stats, crlf_action))
 368                return 0;
 369
 370        /* are we "faking" in place editing ? */
 371        if (src == buf->buf)
 372                to_free = strbuf_detach(buf, NULL);
 373
 374        strbuf_grow(buf, len + stats.lonelf);
 375        for (;;) {
 376                const char *nl = memchr(src, '\n', len);
 377                if (!nl)
 378                        break;
 379                if (nl > src && nl[-1] == '\r') {
 380                        strbuf_add(buf, src, nl + 1 - src);
 381                } else {
 382                        strbuf_add(buf, src, nl - src);
 383                        strbuf_addstr(buf, "\r\n");
 384                }
 385                len -= nl + 1 - src;
 386                src  = nl + 1;
 387        }
 388        strbuf_add(buf, src, len);
 389
 390        free(to_free);
 391        return 1;
 392}
 393
 394struct filter_params {
 395        const char *src;
 396        unsigned long size;
 397        int fd;
 398        const char *cmd;
 399        const char *path;
 400};
 401
 402static int filter_buffer_or_fd(int in, int out, void *data)
 403{
 404        /*
 405         * Spawn cmd and feed the buffer contents through its stdin.
 406         */
 407        struct child_process child_process = CHILD_PROCESS_INIT;
 408        struct filter_params *params = (struct filter_params *)data;
 409        int write_err, status;
 410        const char *argv[] = { NULL, NULL };
 411
 412        /* apply % substitution to cmd */
 413        struct strbuf cmd = STRBUF_INIT;
 414        struct strbuf path = STRBUF_INIT;
 415        struct strbuf_expand_dict_entry dict[] = {
 416                { "f", NULL, },
 417                { NULL, NULL, },
 418        };
 419
 420        /* quote the path to preserve spaces, etc. */
 421        sq_quote_buf(&path, params->path);
 422        dict[0].value = path.buf;
 423
 424        /* expand all %f with the quoted path */
 425        strbuf_expand(&cmd, params->cmd, strbuf_expand_dict_cb, &dict);
 426        strbuf_release(&path);
 427
 428        argv[0] = cmd.buf;
 429
 430        child_process.argv = argv;
 431        child_process.use_shell = 1;
 432        child_process.in = -1;
 433        child_process.out = out;
 434
 435        if (start_command(&child_process)) {
 436                strbuf_release(&cmd);
 437                return error("cannot fork to run external filter '%s'", params->cmd);
 438        }
 439
 440        sigchain_push(SIGPIPE, SIG_IGN);
 441
 442        if (params->src) {
 443                write_err = (write_in_full(child_process.in,
 444                                           params->src, params->size) < 0);
 445                if (errno == EPIPE)
 446                        write_err = 0;
 447        } else {
 448                write_err = copy_fd(params->fd, child_process.in);
 449                if (write_err == COPY_WRITE_ERROR && errno == EPIPE)
 450                        write_err = 0;
 451        }
 452
 453        if (close(child_process.in))
 454                write_err = 1;
 455        if (write_err)
 456                error("cannot feed the input to external filter '%s'", params->cmd);
 457
 458        sigchain_pop(SIGPIPE);
 459
 460        status = finish_command(&child_process);
 461        if (status)
 462                error("external filter '%s' failed %d", params->cmd, status);
 463
 464        strbuf_release(&cmd);
 465        return (write_err || status);
 466}
 467
 468static int apply_single_file_filter(const char *path, const char *src, size_t len, int fd,
 469                        struct strbuf *dst, const char *cmd)
 470{
 471        /*
 472         * Create a pipeline to have the command filter the buffer's
 473         * contents.
 474         *
 475         * (child --> cmd) --> us
 476         */
 477        int err = 0;
 478        struct strbuf nbuf = STRBUF_INIT;
 479        struct async async;
 480        struct filter_params params;
 481
 482        memset(&async, 0, sizeof(async));
 483        async.proc = filter_buffer_or_fd;
 484        async.data = &params;
 485        async.out = -1;
 486        params.src = src;
 487        params.size = len;
 488        params.fd = fd;
 489        params.cmd = cmd;
 490        params.path = path;
 491
 492        fflush(NULL);
 493        if (start_async(&async))
 494                return 0;       /* error was already reported */
 495
 496        if (strbuf_read(&nbuf, async.out, len) < 0) {
 497                err = error("read from external filter '%s' failed", cmd);
 498        }
 499        if (close(async.out)) {
 500                err = error("read from external filter '%s' failed", cmd);
 501        }
 502        if (finish_async(&async)) {
 503                err = error("external filter '%s' failed", cmd);
 504        }
 505
 506        if (!err) {
 507                strbuf_swap(dst, &nbuf);
 508        }
 509        strbuf_release(&nbuf);
 510        return !err;
 511}
 512
 513#define CAP_CLEAN    (1u<<0)
 514#define CAP_SMUDGE   (1u<<1)
 515#define CAP_DELAY    (1u<<2)
 516
 517struct cmd2process {
 518        struct subprocess_entry subprocess; /* must be the first member! */
 519        unsigned int supported_capabilities;
 520};
 521
 522static int subprocess_map_initialized;
 523static struct hashmap subprocess_map;
 524
 525static int start_multi_file_filter_fn(struct subprocess_entry *subprocess)
 526{
 527        static int versions[] = {2, 0};
 528        static struct subprocess_capability capabilities[] = {
 529                { "clean",  CAP_CLEAN  },
 530                { "smudge", CAP_SMUDGE },
 531                { "delay",  CAP_DELAY  },
 532                { NULL, 0 }
 533        };
 534        struct cmd2process *entry = (struct cmd2process *)subprocess;
 535        return subprocess_handshake(subprocess, "git-filter", versions, NULL,
 536                                    capabilities,
 537                                    &entry->supported_capabilities);
 538}
 539
 540static void handle_filter_error(const struct strbuf *filter_status,
 541                                struct cmd2process *entry,
 542                                const unsigned int wanted_capability) {
 543        if (!strcmp(filter_status->buf, "error"))
 544                ; /* The filter signaled a problem with the file. */
 545        else if (!strcmp(filter_status->buf, "abort") && wanted_capability) {
 546                /*
 547                 * The filter signaled a permanent problem. Don't try to filter
 548                 * files with the same command for the lifetime of the current
 549                 * Git process.
 550                 */
 551                 entry->supported_capabilities &= ~wanted_capability;
 552        } else {
 553                /*
 554                 * Something went wrong with the protocol filter.
 555                 * Force shutdown and restart if another blob requires filtering.
 556                 */
 557                error("external filter '%s' failed", entry->subprocess.cmd);
 558                subprocess_stop(&subprocess_map, &entry->subprocess);
 559                free(entry);
 560        }
 561}
 562
 563static int apply_multi_file_filter(const char *path, const char *src, size_t len,
 564                                   int fd, struct strbuf *dst, const char *cmd,
 565                                   const unsigned int wanted_capability,
 566                                   struct delayed_checkout *dco)
 567{
 568        int err;
 569        int can_delay = 0;
 570        struct cmd2process *entry;
 571        struct child_process *process;
 572        struct strbuf nbuf = STRBUF_INIT;
 573        struct strbuf filter_status = STRBUF_INIT;
 574        const char *filter_type;
 575
 576        if (!subprocess_map_initialized) {
 577                subprocess_map_initialized = 1;
 578                hashmap_init(&subprocess_map, cmd2process_cmp, NULL, 0);
 579                entry = NULL;
 580        } else {
 581                entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
 582        }
 583
 584        fflush(NULL);
 585
 586        if (!entry) {
 587                entry = xmalloc(sizeof(*entry));
 588                entry->supported_capabilities = 0;
 589
 590                if (subprocess_start(&subprocess_map, &entry->subprocess, cmd, start_multi_file_filter_fn)) {
 591                        free(entry);
 592                        return 0;
 593                }
 594        }
 595        process = &entry->subprocess.process;
 596
 597        if (!(entry->supported_capabilities & wanted_capability))
 598                return 0;
 599
 600        if (wanted_capability & CAP_CLEAN)
 601                filter_type = "clean";
 602        else if (wanted_capability & CAP_SMUDGE)
 603                filter_type = "smudge";
 604        else
 605                die("unexpected filter type");
 606
 607        sigchain_push(SIGPIPE, SIG_IGN);
 608
 609        assert(strlen(filter_type) < LARGE_PACKET_DATA_MAX - strlen("command=\n"));
 610        err = packet_write_fmt_gently(process->in, "command=%s\n", filter_type);
 611        if (err)
 612                goto done;
 613
 614        err = strlen(path) > LARGE_PACKET_DATA_MAX - strlen("pathname=\n");
 615        if (err) {
 616                error("path name too long for external filter");
 617                goto done;
 618        }
 619
 620        err = packet_write_fmt_gently(process->in, "pathname=%s\n", path);
 621        if (err)
 622                goto done;
 623
 624        if ((entry->supported_capabilities & CAP_DELAY) &&
 625            dco && dco->state == CE_CAN_DELAY) {
 626                can_delay = 1;
 627                err = packet_write_fmt_gently(process->in, "can-delay=1\n");
 628                if (err)
 629                        goto done;
 630        }
 631
 632        err = packet_flush_gently(process->in);
 633        if (err)
 634                goto done;
 635
 636        if (fd >= 0)
 637                err = write_packetized_from_fd(fd, process->in);
 638        else
 639                err = write_packetized_from_buf(src, len, process->in);
 640        if (err)
 641                goto done;
 642
 643        err = subprocess_read_status(process->out, &filter_status);
 644        if (err)
 645                goto done;
 646
 647        if (can_delay && !strcmp(filter_status.buf, "delayed")) {
 648                string_list_insert(&dco->filters, cmd);
 649                string_list_insert(&dco->paths, path);
 650        } else {
 651                /* The filter got the blob and wants to send us a response. */
 652                err = strcmp(filter_status.buf, "success");
 653                if (err)
 654                        goto done;
 655
 656                err = read_packetized_to_strbuf(process->out, &nbuf) < 0;
 657                if (err)
 658                        goto done;
 659
 660                err = subprocess_read_status(process->out, &filter_status);
 661                if (err)
 662                        goto done;
 663
 664                err = strcmp(filter_status.buf, "success");
 665        }
 666
 667done:
 668        sigchain_pop(SIGPIPE);
 669
 670        if (err)
 671                handle_filter_error(&filter_status, entry, wanted_capability);
 672        else
 673                strbuf_swap(dst, &nbuf);
 674        strbuf_release(&nbuf);
 675        return !err;
 676}
 677
 678
 679int async_query_available_blobs(const char *cmd, struct string_list *available_paths)
 680{
 681        int err;
 682        char *line;
 683        struct cmd2process *entry;
 684        struct child_process *process;
 685        struct strbuf filter_status = STRBUF_INIT;
 686
 687        assert(subprocess_map_initialized);
 688        entry = (struct cmd2process *)subprocess_find_entry(&subprocess_map, cmd);
 689        if (!entry) {
 690                error("external filter '%s' is not available anymore although "
 691                      "not all paths have been filtered", cmd);
 692                return 0;
 693        }
 694        process = &entry->subprocess.process;
 695        sigchain_push(SIGPIPE, SIG_IGN);
 696
 697        err = packet_write_fmt_gently(
 698                process->in, "command=list_available_blobs\n");
 699        if (err)
 700                goto done;
 701
 702        err = packet_flush_gently(process->in);
 703        if (err)
 704                goto done;
 705
 706        while ((line = packet_read_line(process->out, NULL))) {
 707                const char *path;
 708                if (skip_prefix(line, "pathname=", &path))
 709                        string_list_insert(available_paths, xstrdup(path));
 710                else
 711                        ; /* ignore unknown keys */
 712        }
 713
 714        err = subprocess_read_status(process->out, &filter_status);
 715        if (err)
 716                goto done;
 717
 718        err = strcmp(filter_status.buf, "success");
 719
 720done:
 721        sigchain_pop(SIGPIPE);
 722
 723        if (err)
 724                handle_filter_error(&filter_status, entry, 0);
 725        return !err;
 726}
 727
 728static struct convert_driver {
 729        const char *name;
 730        struct convert_driver *next;
 731        const char *smudge;
 732        const char *clean;
 733        const char *process;
 734        int required;
 735} *user_convert, **user_convert_tail;
 736
 737static int apply_filter(const char *path, const char *src, size_t len,
 738                        int fd, struct strbuf *dst, struct convert_driver *drv,
 739                        const unsigned int wanted_capability,
 740                        struct delayed_checkout *dco)
 741{
 742        const char *cmd = NULL;
 743
 744        if (!drv)
 745                return 0;
 746
 747        if (!dst)
 748                return 1;
 749
 750        if ((wanted_capability & CAP_CLEAN) && !drv->process && drv->clean)
 751                cmd = drv->clean;
 752        else if ((wanted_capability & CAP_SMUDGE) && !drv->process && drv->smudge)
 753                cmd = drv->smudge;
 754
 755        if (cmd && *cmd)
 756                return apply_single_file_filter(path, src, len, fd, dst, cmd);
 757        else if (drv->process && *drv->process)
 758                return apply_multi_file_filter(path, src, len, fd, dst,
 759                        drv->process, wanted_capability, dco);
 760
 761        return 0;
 762}
 763
 764static int read_convert_config(const char *var, const char *value, void *cb)
 765{
 766        const char *key, *name;
 767        int namelen;
 768        struct convert_driver *drv;
 769
 770        /*
 771         * External conversion drivers are configured using
 772         * "filter.<name>.variable".
 773         */
 774        if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 775                return 0;
 776        for (drv = user_convert; drv; drv = drv->next)
 777                if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 778                        break;
 779        if (!drv) {
 780                drv = xcalloc(1, sizeof(struct convert_driver));
 781                drv->name = xmemdupz(name, namelen);
 782                *user_convert_tail = drv;
 783                user_convert_tail = &(drv->next);
 784        }
 785
 786        /*
 787         * filter.<name>.smudge and filter.<name>.clean specifies
 788         * the command line:
 789         *
 790         *      command-line
 791         *
 792         * The command-line will not be interpolated in any way.
 793         */
 794
 795        if (!strcmp("smudge", key))
 796                return git_config_string(&drv->smudge, var, value);
 797
 798        if (!strcmp("clean", key))
 799                return git_config_string(&drv->clean, var, value);
 800
 801        if (!strcmp("process", key))
 802                return git_config_string(&drv->process, var, value);
 803
 804        if (!strcmp("required", key)) {
 805                drv->required = git_config_bool(var, value);
 806                return 0;
 807        }
 808
 809        return 0;
 810}
 811
 812static int count_ident(const char *cp, unsigned long size)
 813{
 814        /*
 815         * "$Id: 0000000000000000000000000000000000000000 $" <=> "$Id$"
 816         */
 817        int cnt = 0;
 818        char ch;
 819
 820        while (size) {
 821                ch = *cp++;
 822                size--;
 823                if (ch != '$')
 824                        continue;
 825                if (size < 3)
 826                        break;
 827                if (memcmp("Id", cp, 2))
 828                        continue;
 829                ch = cp[2];
 830                cp += 3;
 831                size -= 3;
 832                if (ch == '$')
 833                        cnt++; /* $Id$ */
 834                if (ch != ':')
 835                        continue;
 836
 837                /*
 838                 * "$Id: ... "; scan up to the closing dollar sign and discard.
 839                 */
 840                while (size) {
 841                        ch = *cp++;
 842                        size--;
 843                        if (ch == '$') {
 844                                cnt++;
 845                                break;
 846                        }
 847                        if (ch == '\n')
 848                                break;
 849                }
 850        }
 851        return cnt;
 852}
 853
 854static int ident_to_git(const char *path, const char *src, size_t len,
 855                        struct strbuf *buf, int ident)
 856{
 857        char *dst, *dollar;
 858
 859        if (!ident || (src && !count_ident(src, len)))
 860                return 0;
 861
 862        if (!buf)
 863                return 1;
 864
 865        /* only grow if not in place */
 866        if (strbuf_avail(buf) + buf->len < len)
 867                strbuf_grow(buf, len - buf->len);
 868        dst = buf->buf;
 869        for (;;) {
 870                dollar = memchr(src, '$', len);
 871                if (!dollar)
 872                        break;
 873                memmove(dst, src, dollar + 1 - src);
 874                dst += dollar + 1 - src;
 875                len -= dollar + 1 - src;
 876                src  = dollar + 1;
 877
 878                if (len > 3 && !memcmp(src, "Id:", 3)) {
 879                        dollar = memchr(src + 3, '$', len - 3);
 880                        if (!dollar)
 881                                break;
 882                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 883                                /* Line break before the next dollar. */
 884                                continue;
 885                        }
 886
 887                        memcpy(dst, "Id$", 3);
 888                        dst += 3;
 889                        len -= dollar + 1 - src;
 890                        src  = dollar + 1;
 891                }
 892        }
 893        memmove(dst, src, len);
 894        strbuf_setlen(buf, dst + len - buf->buf);
 895        return 1;
 896}
 897
 898static int ident_to_worktree(const char *path, const char *src, size_t len,
 899                             struct strbuf *buf, int ident)
 900{
 901        struct object_id oid;
 902        char *to_free = NULL, *dollar, *spc;
 903        int cnt;
 904
 905        if (!ident)
 906                return 0;
 907
 908        cnt = count_ident(src, len);
 909        if (!cnt)
 910                return 0;
 911
 912        /* are we "faking" in place editing ? */
 913        if (src == buf->buf)
 914                to_free = strbuf_detach(buf, NULL);
 915        hash_object_file(src, len, "blob", &oid);
 916
 917        strbuf_grow(buf, len + cnt * (the_hash_algo->hexsz + 3));
 918        for (;;) {
 919                /* step 1: run to the next '$' */
 920                dollar = memchr(src, '$', len);
 921                if (!dollar)
 922                        break;
 923                strbuf_add(buf, src, dollar + 1 - src);
 924                len -= dollar + 1 - src;
 925                src  = dollar + 1;
 926
 927                /* step 2: does it looks like a bit like Id:xxx$ or Id$ ? */
 928                if (len < 3 || memcmp("Id", src, 2))
 929                        continue;
 930
 931                /* step 3: skip over Id$ or Id:xxxxx$ */
 932                if (src[2] == '$') {
 933                        src += 3;
 934                        len -= 3;
 935                } else if (src[2] == ':') {
 936                        /*
 937                         * It's possible that an expanded Id has crept its way into the
 938                         * repository, we cope with that by stripping the expansion out.
 939                         * This is probably not a good idea, since it will cause changes
 940                         * on checkout, which won't go away by stash, but let's keep it
 941                         * for git-style ids.
 942                         */
 943                        dollar = memchr(src + 3, '$', len - 3);
 944                        if (!dollar) {
 945                                /* incomplete keyword, no more '$', so just quit the loop */
 946                                break;
 947                        }
 948
 949                        if (memchr(src + 3, '\n', dollar - src - 3)) {
 950                                /* Line break before the next dollar. */
 951                                continue;
 952                        }
 953
 954                        spc = memchr(src + 4, ' ', dollar - src - 4);
 955                        if (spc && spc < dollar-1) {
 956                                /* There are spaces in unexpected places.
 957                                 * This is probably an id from some other
 958                                 * versioning system. Keep it for now.
 959                                 */
 960                                continue;
 961                        }
 962
 963                        len -= dollar + 1 - src;
 964                        src  = dollar + 1;
 965                } else {
 966                        /* it wasn't a "Id$" or "Id:xxxx$" */
 967                        continue;
 968                }
 969
 970                /* step 4: substitute */
 971                strbuf_addstr(buf, "Id: ");
 972                strbuf_addstr(buf, oid_to_hex(&oid));
 973                strbuf_addstr(buf, " $");
 974        }
 975        strbuf_add(buf, src, len);
 976
 977        free(to_free);
 978        return 1;
 979}
 980
 981static enum crlf_action git_path_check_crlf(struct attr_check_item *check)
 982{
 983        const char *value = check->value;
 984
 985        if (ATTR_TRUE(value))
 986                return CRLF_TEXT;
 987        else if (ATTR_FALSE(value))
 988                return CRLF_BINARY;
 989        else if (ATTR_UNSET(value))
 990                ;
 991        else if (!strcmp(value, "input"))
 992                return CRLF_TEXT_INPUT;
 993        else if (!strcmp(value, "auto"))
 994                return CRLF_AUTO;
 995        return CRLF_UNDEFINED;
 996}
 997
 998static enum eol git_path_check_eol(struct attr_check_item *check)
 999{
1000        const char *value = check->value;
1001
1002        if (ATTR_UNSET(value))
1003                ;
1004        else if (!strcmp(value, "lf"))
1005                return EOL_LF;
1006        else if (!strcmp(value, "crlf"))
1007                return EOL_CRLF;
1008        return EOL_UNSET;
1009}
1010
1011static struct convert_driver *git_path_check_convert(struct attr_check_item *check)
1012{
1013        const char *value = check->value;
1014        struct convert_driver *drv;
1015
1016        if (ATTR_TRUE(value) || ATTR_FALSE(value) || ATTR_UNSET(value))
1017                return NULL;
1018        for (drv = user_convert; drv; drv = drv->next)
1019                if (!strcmp(value, drv->name))
1020                        return drv;
1021        return NULL;
1022}
1023
1024static int git_path_check_ident(struct attr_check_item *check)
1025{
1026        const char *value = check->value;
1027
1028        return !!ATTR_TRUE(value);
1029}
1030
1031struct conv_attrs {
1032        struct convert_driver *drv;
1033        enum crlf_action attr_action; /* What attr says */
1034        enum crlf_action crlf_action; /* When no attr is set, use core.autocrlf */
1035        int ident;
1036};
1037
1038static void convert_attrs(struct conv_attrs *ca, const char *path)
1039{
1040        static struct attr_check *check;
1041
1042        if (!check) {
1043                check = attr_check_initl("crlf", "ident", "filter",
1044                                         "eol", "text", NULL);
1045                user_convert_tail = &user_convert;
1046                git_config(read_convert_config, NULL);
1047        }
1048
1049        if (!git_check_attr(path, check)) {
1050                struct attr_check_item *ccheck = check->items;
1051                ca->crlf_action = git_path_check_crlf(ccheck + 4);
1052                if (ca->crlf_action == CRLF_UNDEFINED)
1053                        ca->crlf_action = git_path_check_crlf(ccheck + 0);
1054                ca->ident = git_path_check_ident(ccheck + 1);
1055                ca->drv = git_path_check_convert(ccheck + 2);
1056                if (ca->crlf_action != CRLF_BINARY) {
1057                        enum eol eol_attr = git_path_check_eol(ccheck + 3);
1058                        if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_LF)
1059                                ca->crlf_action = CRLF_AUTO_INPUT;
1060                        else if (ca->crlf_action == CRLF_AUTO && eol_attr == EOL_CRLF)
1061                                ca->crlf_action = CRLF_AUTO_CRLF;
1062                        else if (eol_attr == EOL_LF)
1063                                ca->crlf_action = CRLF_TEXT_INPUT;
1064                        else if (eol_attr == EOL_CRLF)
1065                                ca->crlf_action = CRLF_TEXT_CRLF;
1066                }
1067        } else {
1068                ca->drv = NULL;
1069                ca->crlf_action = CRLF_UNDEFINED;
1070                ca->ident = 0;
1071        }
1072
1073        /* Save attr and make a decision for action */
1074        ca->attr_action = ca->crlf_action;
1075        if (ca->crlf_action == CRLF_TEXT)
1076                ca->crlf_action = text_eol_is_crlf() ? CRLF_TEXT_CRLF : CRLF_TEXT_INPUT;
1077        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_FALSE)
1078                ca->crlf_action = CRLF_BINARY;
1079        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_TRUE)
1080                ca->crlf_action = CRLF_AUTO_CRLF;
1081        if (ca->crlf_action == CRLF_UNDEFINED && auto_crlf == AUTO_CRLF_INPUT)
1082                ca->crlf_action = CRLF_AUTO_INPUT;
1083}
1084
1085int would_convert_to_git_filter_fd(const char *path)
1086{
1087        struct conv_attrs ca;
1088
1089        convert_attrs(&ca, path);
1090        if (!ca.drv)
1091                return 0;
1092
1093        /*
1094         * Apply a filter to an fd only if the filter is required to succeed.
1095         * We must die if the filter fails, because the original data before
1096         * filtering is not available.
1097         */
1098        if (!ca.drv->required)
1099                return 0;
1100
1101        return apply_filter(path, NULL, 0, -1, NULL, ca.drv, CAP_CLEAN, NULL);
1102}
1103
1104const char *get_convert_attr_ascii(const char *path)
1105{
1106        struct conv_attrs ca;
1107
1108        convert_attrs(&ca, path);
1109        switch (ca.attr_action) {
1110        case CRLF_UNDEFINED:
1111                return "";
1112        case CRLF_BINARY:
1113                return "-text";
1114        case CRLF_TEXT:
1115                return "text";
1116        case CRLF_TEXT_INPUT:
1117                return "text eol=lf";
1118        case CRLF_TEXT_CRLF:
1119                return "text eol=crlf";
1120        case CRLF_AUTO:
1121                return "text=auto";
1122        case CRLF_AUTO_CRLF:
1123                return "text=auto eol=crlf";
1124        case CRLF_AUTO_INPUT:
1125                return "text=auto eol=lf";
1126        }
1127        return "";
1128}
1129
1130int convert_to_git(const struct index_state *istate,
1131                   const char *path, const char *src, size_t len,
1132                   struct strbuf *dst, int conv_flags)
1133{
1134        int ret = 0;
1135        struct conv_attrs ca;
1136
1137        convert_attrs(&ca, path);
1138
1139        ret |= apply_filter(path, src, len, -1, dst, ca.drv, CAP_CLEAN, NULL);
1140        if (!ret && ca.drv && ca.drv->required)
1141                die("%s: clean filter '%s' failed", path, ca.drv->name);
1142
1143        if (ret && dst) {
1144                src = dst->buf;
1145                len = dst->len;
1146        }
1147        if (!(conv_flags & CONV_EOL_KEEP_CRLF)) {
1148                ret |= crlf_to_git(istate, path, src, len, dst, ca.crlf_action, conv_flags);
1149                if (ret && dst) {
1150                        src = dst->buf;
1151                        len = dst->len;
1152                }
1153        }
1154        return ret | ident_to_git(path, src, len, dst, ca.ident);
1155}
1156
1157void convert_to_git_filter_fd(const struct index_state *istate,
1158                              const char *path, int fd, struct strbuf *dst,
1159                              int conv_flags)
1160{
1161        struct conv_attrs ca;
1162        convert_attrs(&ca, path);
1163
1164        assert(ca.drv);
1165        assert(ca.drv->clean || ca.drv->process);
1166
1167        if (!apply_filter(path, NULL, 0, fd, dst, ca.drv, CAP_CLEAN, NULL))
1168                die("%s: clean filter '%s' failed", path, ca.drv->name);
1169
1170        crlf_to_git(istate, path, dst->buf, dst->len, dst, ca.crlf_action, conv_flags);
1171        ident_to_git(path, dst->buf, dst->len, dst, ca.ident);
1172}
1173
1174static int convert_to_working_tree_internal(const char *path, const char *src,
1175                                            size_t len, struct strbuf *dst,
1176                                            int normalizing, struct delayed_checkout *dco)
1177{
1178        int ret = 0, ret_filter = 0;
1179        struct conv_attrs ca;
1180
1181        convert_attrs(&ca, path);
1182
1183        ret |= ident_to_worktree(path, src, len, dst, ca.ident);
1184        if (ret) {
1185                src = dst->buf;
1186                len = dst->len;
1187        }
1188        /*
1189         * CRLF conversion can be skipped if normalizing, unless there
1190         * is a smudge or process filter (even if the process filter doesn't
1191         * support smudge).  The filters might expect CRLFs.
1192         */
1193        if ((ca.drv && (ca.drv->smudge || ca.drv->process)) || !normalizing) {
1194                ret |= crlf_to_worktree(path, src, len, dst, ca.crlf_action);
1195                if (ret) {
1196                        src = dst->buf;
1197                        len = dst->len;
1198                }
1199        }
1200
1201        ret_filter = apply_filter(
1202                path, src, len, -1, dst, ca.drv, CAP_SMUDGE, dco);
1203        if (!ret_filter && ca.drv && ca.drv->required)
1204                die("%s: smudge filter %s failed", path, ca.drv->name);
1205
1206        return ret | ret_filter;
1207}
1208
1209int async_convert_to_working_tree(const char *path, const char *src,
1210                                  size_t len, struct strbuf *dst,
1211                                  void *dco)
1212{
1213        return convert_to_working_tree_internal(path, src, len, dst, 0, dco);
1214}
1215
1216int convert_to_working_tree(const char *path, const char *src, size_t len, struct strbuf *dst)
1217{
1218        return convert_to_working_tree_internal(path, src, len, dst, 0, NULL);
1219}
1220
1221int renormalize_buffer(const struct index_state *istate, const char *path,
1222                       const char *src, size_t len, struct strbuf *dst)
1223{
1224        int ret = convert_to_working_tree_internal(path, src, len, dst, 1, NULL);
1225        if (ret) {
1226                src = dst->buf;
1227                len = dst->len;
1228        }
1229        return ret | convert_to_git(istate, path, src, len, dst, CONV_EOL_RENORMALIZE);
1230}
1231
1232/*****************************************************************
1233 *
1234 * Streaming conversion support
1235 *
1236 *****************************************************************/
1237
1238typedef int (*filter_fn)(struct stream_filter *,
1239                         const char *input, size_t *isize_p,
1240                         char *output, size_t *osize_p);
1241typedef void (*free_fn)(struct stream_filter *);
1242
1243struct stream_filter_vtbl {
1244        filter_fn filter;
1245        free_fn free;
1246};
1247
1248struct stream_filter {
1249        struct stream_filter_vtbl *vtbl;
1250};
1251
1252static int null_filter_fn(struct stream_filter *filter,
1253                          const char *input, size_t *isize_p,
1254                          char *output, size_t *osize_p)
1255{
1256        size_t count;
1257
1258        if (!input)
1259                return 0; /* we do not keep any states */
1260        count = *isize_p;
1261        if (*osize_p < count)
1262                count = *osize_p;
1263        if (count) {
1264                memmove(output, input, count);
1265                *isize_p -= count;
1266                *osize_p -= count;
1267        }
1268        return 0;
1269}
1270
1271static void null_free_fn(struct stream_filter *filter)
1272{
1273        ; /* nothing -- null instances are shared */
1274}
1275
1276static struct stream_filter_vtbl null_vtbl = {
1277        null_filter_fn,
1278        null_free_fn,
1279};
1280
1281static struct stream_filter null_filter_singleton = {
1282        &null_vtbl,
1283};
1284
1285int is_null_stream_filter(struct stream_filter *filter)
1286{
1287        return filter == &null_filter_singleton;
1288}
1289
1290
1291/*
1292 * LF-to-CRLF filter
1293 */
1294
1295struct lf_to_crlf_filter {
1296        struct stream_filter filter;
1297        unsigned has_held:1;
1298        char held;
1299};
1300
1301static int lf_to_crlf_filter_fn(struct stream_filter *filter,
1302                                const char *input, size_t *isize_p,
1303                                char *output, size_t *osize_p)
1304{
1305        size_t count, o = 0;
1306        struct lf_to_crlf_filter *lf_to_crlf = (struct lf_to_crlf_filter *)filter;
1307
1308        /*
1309         * We may be holding onto the CR to see if it is followed by a
1310         * LF, in which case we would need to go to the main loop.
1311         * Otherwise, just emit it to the output stream.
1312         */
1313        if (lf_to_crlf->has_held && (lf_to_crlf->held != '\r' || !input)) {
1314                output[o++] = lf_to_crlf->held;
1315                lf_to_crlf->has_held = 0;
1316        }
1317
1318        /* We are told to drain */
1319        if (!input) {
1320                *osize_p -= o;
1321                return 0;
1322        }
1323
1324        count = *isize_p;
1325        if (count || lf_to_crlf->has_held) {
1326                size_t i;
1327                int was_cr = 0;
1328
1329                if (lf_to_crlf->has_held) {
1330                        was_cr = 1;
1331                        lf_to_crlf->has_held = 0;
1332                }
1333
1334                for (i = 0; o < *osize_p && i < count; i++) {
1335                        char ch = input[i];
1336
1337                        if (ch == '\n') {
1338                                output[o++] = '\r';
1339                        } else if (was_cr) {
1340                                /*
1341                                 * Previous round saw CR and it is not followed
1342                                 * by a LF; emit the CR before processing the
1343                                 * current character.
1344                                 */
1345                                output[o++] = '\r';
1346                        }
1347
1348                        /*
1349                         * We may have consumed the last output slot,
1350                         * in which case we need to break out of this
1351                         * loop; hold the current character before
1352                         * returning.
1353                         */
1354                        if (*osize_p <= o) {
1355                                lf_to_crlf->has_held = 1;
1356                                lf_to_crlf->held = ch;
1357                                continue; /* break but increment i */
1358                        }
1359
1360                        if (ch == '\r') {
1361                                was_cr = 1;
1362                                continue;
1363                        }
1364
1365                        was_cr = 0;
1366                        output[o++] = ch;
1367                }
1368
1369                *osize_p -= o;
1370                *isize_p -= i;
1371
1372                if (!lf_to_crlf->has_held && was_cr) {
1373                        lf_to_crlf->has_held = 1;
1374                        lf_to_crlf->held = '\r';
1375                }
1376        }
1377        return 0;
1378}
1379
1380static void lf_to_crlf_free_fn(struct stream_filter *filter)
1381{
1382        free(filter);
1383}
1384
1385static struct stream_filter_vtbl lf_to_crlf_vtbl = {
1386        lf_to_crlf_filter_fn,
1387        lf_to_crlf_free_fn,
1388};
1389
1390static struct stream_filter *lf_to_crlf_filter(void)
1391{
1392        struct lf_to_crlf_filter *lf_to_crlf = xcalloc(1, sizeof(*lf_to_crlf));
1393
1394        lf_to_crlf->filter.vtbl = &lf_to_crlf_vtbl;
1395        return (struct stream_filter *)lf_to_crlf;
1396}
1397
1398/*
1399 * Cascade filter
1400 */
1401#define FILTER_BUFFER 1024
1402struct cascade_filter {
1403        struct stream_filter filter;
1404        struct stream_filter *one;
1405        struct stream_filter *two;
1406        char buf[FILTER_BUFFER];
1407        int end, ptr;
1408};
1409
1410static int cascade_filter_fn(struct stream_filter *filter,
1411                             const char *input, size_t *isize_p,
1412                             char *output, size_t *osize_p)
1413{
1414        struct cascade_filter *cas = (struct cascade_filter *) filter;
1415        size_t filled = 0;
1416        size_t sz = *osize_p;
1417        size_t to_feed, remaining;
1418
1419        /*
1420         * input -- (one) --> buf -- (two) --> output
1421         */
1422        while (filled < sz) {
1423                remaining = sz - filled;
1424
1425                /* do we already have something to feed two with? */
1426                if (cas->ptr < cas->end) {
1427                        to_feed = cas->end - cas->ptr;
1428                        if (stream_filter(cas->two,
1429                                          cas->buf + cas->ptr, &to_feed,
1430                                          output + filled, &remaining))
1431                                return -1;
1432                        cas->ptr += (cas->end - cas->ptr) - to_feed;
1433                        filled = sz - remaining;
1434                        continue;
1435                }
1436
1437                /* feed one from upstream and have it emit into our buffer */
1438                to_feed = input ? *isize_p : 0;
1439                if (input && !to_feed)
1440                        break;
1441                remaining = sizeof(cas->buf);
1442                if (stream_filter(cas->one,
1443                                  input, &to_feed,
1444                                  cas->buf, &remaining))
1445                        return -1;
1446                cas->end = sizeof(cas->buf) - remaining;
1447                cas->ptr = 0;
1448                if (input) {
1449                        size_t fed = *isize_p - to_feed;
1450                        *isize_p -= fed;
1451                        input += fed;
1452                }
1453
1454                /* do we know that we drained one completely? */
1455                if (input || cas->end)
1456                        continue;
1457
1458                /* tell two to drain; we have nothing more to give it */
1459                to_feed = 0;
1460                remaining = sz - filled;
1461                if (stream_filter(cas->two,
1462                                  NULL, &to_feed,
1463                                  output + filled, &remaining))
1464                        return -1;
1465                if (remaining == (sz - filled))
1466                        break; /* completely drained two */
1467                filled = sz - remaining;
1468        }
1469        *osize_p -= filled;
1470        return 0;
1471}
1472
1473static void cascade_free_fn(struct stream_filter *filter)
1474{
1475        struct cascade_filter *cas = (struct cascade_filter *)filter;
1476        free_stream_filter(cas->one);
1477        free_stream_filter(cas->two);
1478        free(filter);
1479}
1480
1481static struct stream_filter_vtbl cascade_vtbl = {
1482        cascade_filter_fn,
1483        cascade_free_fn,
1484};
1485
1486static struct stream_filter *cascade_filter(struct stream_filter *one,
1487                                            struct stream_filter *two)
1488{
1489        struct cascade_filter *cascade;
1490
1491        if (!one || is_null_stream_filter(one))
1492                return two;
1493        if (!two || is_null_stream_filter(two))
1494                return one;
1495
1496        cascade = xmalloc(sizeof(*cascade));
1497        cascade->one = one;
1498        cascade->two = two;
1499        cascade->end = cascade->ptr = 0;
1500        cascade->filter.vtbl = &cascade_vtbl;
1501        return (struct stream_filter *)cascade;
1502}
1503
1504/*
1505 * ident filter
1506 */
1507#define IDENT_DRAINING (-1)
1508#define IDENT_SKIPPING (-2)
1509struct ident_filter {
1510        struct stream_filter filter;
1511        struct strbuf left;
1512        int state;
1513        char ident[GIT_MAX_HEXSZ + 5]; /* ": x40 $" */
1514};
1515
1516static int is_foreign_ident(const char *str)
1517{
1518        int i;
1519
1520        if (!skip_prefix(str, "$Id: ", &str))
1521                return 0;
1522        for (i = 0; str[i]; i++) {
1523                if (isspace(str[i]) && str[i+1] != '$')
1524                        return 1;
1525        }
1526        return 0;
1527}
1528
1529static void ident_drain(struct ident_filter *ident, char **output_p, size_t *osize_p)
1530{
1531        size_t to_drain = ident->left.len;
1532
1533        if (*osize_p < to_drain)
1534                to_drain = *osize_p;
1535        if (to_drain) {
1536                memcpy(*output_p, ident->left.buf, to_drain);
1537                strbuf_remove(&ident->left, 0, to_drain);
1538                *output_p += to_drain;
1539                *osize_p -= to_drain;
1540        }
1541        if (!ident->left.len)
1542                ident->state = 0;
1543}
1544
1545static int ident_filter_fn(struct stream_filter *filter,
1546                           const char *input, size_t *isize_p,
1547                           char *output, size_t *osize_p)
1548{
1549        struct ident_filter *ident = (struct ident_filter *)filter;
1550        static const char head[] = "$Id";
1551
1552        if (!input) {
1553                /* drain upon eof */
1554                switch (ident->state) {
1555                default:
1556                        strbuf_add(&ident->left, head, ident->state);
1557                        /* fallthrough */
1558                case IDENT_SKIPPING:
1559                        /* fallthrough */
1560                case IDENT_DRAINING:
1561                        ident_drain(ident, &output, osize_p);
1562                }
1563                return 0;
1564        }
1565
1566        while (*isize_p || (ident->state == IDENT_DRAINING)) {
1567                int ch;
1568
1569                if (ident->state == IDENT_DRAINING) {
1570                        ident_drain(ident, &output, osize_p);
1571                        if (!*osize_p)
1572                                break;
1573                        continue;
1574                }
1575
1576                ch = *(input++);
1577                (*isize_p)--;
1578
1579                if (ident->state == IDENT_SKIPPING) {
1580                        /*
1581                         * Skipping until '$' or LF, but keeping them
1582                         * in case it is a foreign ident.
1583                         */
1584                        strbuf_addch(&ident->left, ch);
1585                        if (ch != '\n' && ch != '$')
1586                                continue;
1587                        if (ch == '$' && !is_foreign_ident(ident->left.buf)) {
1588                                strbuf_setlen(&ident->left, sizeof(head) - 1);
1589                                strbuf_addstr(&ident->left, ident->ident);
1590                        }
1591                        ident->state = IDENT_DRAINING;
1592                        continue;
1593                }
1594
1595                if (ident->state < sizeof(head) &&
1596                    head[ident->state] == ch) {
1597                        ident->state++;
1598                        continue;
1599                }
1600
1601                if (ident->state)
1602                        strbuf_add(&ident->left, head, ident->state);
1603                if (ident->state == sizeof(head) - 1) {
1604                        if (ch != ':' && ch != '$') {
1605                                strbuf_addch(&ident->left, ch);
1606                                ident->state = 0;
1607                                continue;
1608                        }
1609
1610                        if (ch == ':') {
1611                                strbuf_addch(&ident->left, ch);
1612                                ident->state = IDENT_SKIPPING;
1613                        } else {
1614                                strbuf_addstr(&ident->left, ident->ident);
1615                                ident->state = IDENT_DRAINING;
1616                        }
1617                        continue;
1618                }
1619
1620                strbuf_addch(&ident->left, ch);
1621                ident->state = IDENT_DRAINING;
1622        }
1623        return 0;
1624}
1625
1626static void ident_free_fn(struct stream_filter *filter)
1627{
1628        struct ident_filter *ident = (struct ident_filter *)filter;
1629        strbuf_release(&ident->left);
1630        free(filter);
1631}
1632
1633static struct stream_filter_vtbl ident_vtbl = {
1634        ident_filter_fn,
1635        ident_free_fn,
1636};
1637
1638static struct stream_filter *ident_filter(const struct object_id *oid)
1639{
1640        struct ident_filter *ident = xmalloc(sizeof(*ident));
1641
1642        xsnprintf(ident->ident, sizeof(ident->ident),
1643                  ": %s $", oid_to_hex(oid));
1644        strbuf_init(&ident->left, 0);
1645        ident->filter.vtbl = &ident_vtbl;
1646        ident->state = 0;
1647        return (struct stream_filter *)ident;
1648}
1649
1650/*
1651 * Return an appropriately constructed filter for the path, or NULL if
1652 * the contents cannot be filtered without reading the whole thing
1653 * in-core.
1654 *
1655 * Note that you would be crazy to set CRLF, smuge/clean or ident to a
1656 * large binary blob you would want us not to slurp into the memory!
1657 */
1658struct stream_filter *get_stream_filter(const char *path, const struct object_id *oid)
1659{
1660        struct conv_attrs ca;
1661        struct stream_filter *filter = NULL;
1662
1663        convert_attrs(&ca, path);
1664        if (ca.drv && (ca.drv->process || ca.drv->smudge || ca.drv->clean))
1665                return NULL;
1666
1667        if (ca.crlf_action == CRLF_AUTO || ca.crlf_action == CRLF_AUTO_CRLF)
1668                return NULL;
1669
1670        if (ca.ident)
1671                filter = ident_filter(oid);
1672
1673        if (output_eol(ca.crlf_action) == EOL_CRLF)
1674                filter = cascade_filter(filter, lf_to_crlf_filter());
1675        else
1676                filter = cascade_filter(filter, &null_filter_singleton);
1677
1678        return filter;
1679}
1680
1681void free_stream_filter(struct stream_filter *filter)
1682{
1683        filter->vtbl->free(filter);
1684}
1685
1686int stream_filter(struct stream_filter *filter,
1687                  const char *input, size_t *isize_p,
1688                  char *output, size_t *osize_p)
1689{
1690        return filter->vtbl->filter(filter, input, isize_p, output, osize_p);
1691}