git.oblomov.eu Git - git/blob - builtin/fast-export.c

   1 /*
   2  * "git fast-export" builtin command
   3  *
   4  * Copyright (C) 2007 Johannes E. Schindelin
   5  */
   6 #include "builtin.h"
   7 #include "cache.h"
   8 #include "config.h"
   9 #include "refs.h"
  10 #include "refspec.h"
  11 #include "object-store.h"
  12 #include "commit.h"
  13 #include "object.h"
  14 #include "tag.h"
  15 #include "diff.h"
  16 #include "diffcore.h"
  17 #include "log-tree.h"
  18 #include "revision.h"
  19 #include "decorate.h"
  20 #include "string-list.h"
  21 #include "utf8.h"
  22 #include "parse-options.h"
  23 #include "quote.h"
  24 #include "remote.h"
  25 #include "blob.h"
  26 #include "commit-slab.h"
  27
  28 static const char *fast_export_usage[] = {
  29         N_("git fast-export [rev-list-opts]"),
  30         NULL
  31 };
  32
  33 static int progress;
  34 static enum { SIGNED_TAG_ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = SIGNED_TAG_ABORT;
  35 static enum { TAG_FILTERING_ABORT, DROP, REWRITE } tag_of_filtered_mode = TAG_FILTERING_ABORT;
  36 static enum { REENCODE_ABORT, REENCODE_YES, REENCODE_NO } reencode_mode = REENCODE_ABORT;
  37 static int fake_missing_tagger;
  38 static int use_done_feature;
  39 static int no_data;
  40 static int full_tree;
  41 static int reference_excluded_commits;
  42 static int show_original_ids;
  43 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
  44 static struct string_list tag_refs = STRING_LIST_INIT_NODUP;
  45 static struct refspec refspecs = REFSPEC_INIT_FETCH;
  46 static int anonymize;
  47 static struct revision_sources revision_sources;
  48
  49 static int parse_opt_signed_tag_mode(const struct option *opt,
  50                                      const char *arg, int unset)
  51 {
  52         if (unset || !strcmp(arg, "abort"))
  53                 signed_tag_mode = SIGNED_TAG_ABORT;
  54         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
  55                 signed_tag_mode = VERBATIM;
  56         else if (!strcmp(arg, "warn"))
  57                 signed_tag_mode = WARN;
  58         else if (!strcmp(arg, "warn-strip"))
  59                 signed_tag_mode = WARN_STRIP;
  60         else if (!strcmp(arg, "strip"))
  61                 signed_tag_mode = STRIP;
  62         else
  63                 return error("Unknown signed-tags mode: %s", arg);
  64         return 0;
  65 }
  66
  67 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
  68                                           const char *arg, int unset)
  69 {
  70         if (unset || !strcmp(arg, "abort"))
  71                 tag_of_filtered_mode = TAG_FILTERING_ABORT;
  72         else if (!strcmp(arg, "drop"))
  73                 tag_of_filtered_mode = DROP;
  74         else if (!strcmp(arg, "rewrite"))
  75                 tag_of_filtered_mode = REWRITE;
  76         else
  77                 return error("Unknown tag-of-filtered mode: %s", arg);
  78         return 0;
  79 }
  80
  81 static int parse_opt_reencode_mode(const struct option *opt,
  82                                    const char *arg, int unset)
  83 {
  84         if (unset) {
  85                 reencode_mode = REENCODE_ABORT;
  86                 return 0;
  87         }
  88
  89         switch (git_parse_maybe_bool(arg)) {
  90         case 0:
  91                 reencode_mode = REENCODE_NO;
  92                 break;
  93         case 1:
  94                 reencode_mode = REENCODE_YES;
  95                 break;
  96         default:
  97                 if (!strcasecmp(arg, "abort"))
  98                         reencode_mode = REENCODE_ABORT;
  99                 else
 100                         return error("Unknown reencoding mode: %s", arg);
 101         }
 102
 103         return 0;
 104 }
 105
 106 static struct decoration idnums;
 107 static uint32_t last_idnum;
 108
 109 static int has_unshown_parent(struct commit *commit)
 110 {
 111         struct commit_list *parent;
 112
 113         for (parent = commit->parents; parent; parent = parent->next)
 114                 if (!(parent->item->object.flags & SHOWN) &&
 115                     !(parent->item->object.flags & UNINTERESTING))
 116                         return 1;
 117         return 0;
 118 }
 119
 120 struct anonymized_entry {
 121         struct hashmap_entry hash;
 122         const char *orig;
 123         size_t orig_len;
 124         const char *anon;
 125         size_t anon_len;
 126 };
 127
 128 static int anonymized_entry_cmp(const void *unused_cmp_data,
 129                                 const void *va, const void *vb,
 130                                 const void *unused_keydata)
 131 {
 132         const struct anonymized_entry *a = va, *b = vb;
 133         return a->orig_len != b->orig_len ||
 134                 memcmp(a->orig, b->orig, a->orig_len);
 135 }
 136
 137 /*
 138  * Basically keep a cache of X->Y so that we can repeatedly replace
 139  * the same anonymized string with another. The actual generation
 140  * is farmed out to the generate function.
 141  */
 142 static const void *anonymize_mem(struct hashmap *map,
 143                                  void *(*generate)(const void *, size_t *),
 144                                  const void *orig, size_t *len)
 145 {
 146         struct anonymized_entry key, *ret;
 147
 148         if (!map->cmpfn)
 149                 hashmap_init(map, anonymized_entry_cmp, NULL, 0);
 150
 151         hashmap_entry_init(&key, memhash(orig, *len));
 152         key.orig = orig;
 153         key.orig_len = *len;
 154         ret = hashmap_get(map, &key, NULL);
 155
 156         if (!ret) {
 157                 ret = xmalloc(sizeof(*ret));
 158                 hashmap_entry_init(&ret->hash, key.hash.hash);
 159                 ret->orig = xstrdup(orig);
 160                 ret->orig_len = *len;
 161                 ret->anon = generate(orig, len);
 162                 ret->anon_len = *len;
 163                 hashmap_put(map, ret);
 164         }
 165
 166         *len = ret->anon_len;
 167         return ret->anon;
 168 }
 169
 170 /*
 171  * We anonymize each component of a path individually,
 172  * so that paths a/b and a/c will share a common root.
 173  * The paths are cached via anonymize_mem so that repeated
 174  * lookups for "a" will yield the same value.
 175  */
 176 static void anonymize_path(struct strbuf *out, const char *path,
 177                            struct hashmap *map,
 178                            void *(*generate)(const void *, size_t *))
 179 {
 180         while (*path) {
 181                 const char *end_of_component = strchrnul(path, '/');
 182                 size_t len = end_of_component - path;
 183                 const char *c = anonymize_mem(map, generate, path, &len);
 184                 strbuf_add(out, c, len);
 185                 path = end_of_component;
 186                 if (*path)
 187                         strbuf_addch(out, *path++);
 188         }
 189 }
 190
 191 static inline void *mark_to_ptr(uint32_t mark)
 192 {
 193         return (void *)(uintptr_t)mark;
 194 }
 195
 196 static inline uint32_t ptr_to_mark(void * mark)
 197 {
 198         return (uint32_t)(uintptr_t)mark;
 199 }
 200
 201 static inline void mark_object(struct object *object, uint32_t mark)
 202 {
 203         add_decoration(&idnums, object, mark_to_ptr(mark));
 204 }
 205
 206 static inline void mark_next_object(struct object *object)
 207 {
 208         mark_object(object, ++last_idnum);
 209 }
 210
 211 static int get_object_mark(struct object *object)
 212 {
 213         void *decoration = lookup_decoration(&idnums, object);
 214         if (!decoration)
 215                 return 0;
 216         return ptr_to_mark(decoration);
 217 }
 218
 219 static struct commit *rewrite_commit(struct commit *p)
 220 {
 221         for (;;) {
 222                 if (p->parents && p->parents->next)
 223                         break;
 224                 if (p->object.flags & UNINTERESTING)
 225                         break;
 226                 if (!(p->object.flags & TREESAME))
 227                         break;
 228                 if (!p->parents)
 229                         return NULL;
 230                 p = p->parents->item;
 231         }
 232         return p;
 233 }
 234
 235 static void show_progress(void)
 236 {
 237         static int counter = 0;
 238         if (!progress)
 239                 return;
 240         if ((++counter % progress) == 0)
 241                 printf("progress %d objects\n", counter);
 242 }
 243
 244 /*
 245  * Ideally we would want some transformation of the blob data here
 246  * that is unreversible, but would still be the same size and have
 247  * the same data relationship to other blobs (so that we get the same
 248  * delta and packing behavior as the original). But the first and last
 249  * requirements there are probably mutually exclusive, so let's take
 250  * the easy way out for now, and just generate arbitrary content.
 251  *
 252  * There's no need to cache this result with anonymize_mem, since
 253  * we already handle blob content caching with marks.
 254  */
 255 static char *anonymize_blob(unsigned long *size)
 256 {
 257         static int counter;
 258         struct strbuf out = STRBUF_INIT;
 259         strbuf_addf(&out, "anonymous blob %d", counter++);
 260         *size = out.len;
 261         return strbuf_detach(&out, NULL);
 262 }
 263
 264 static void export_blob(const struct object_id *oid)
 265 {
 266         unsigned long size;
 267         enum object_type type;
 268         char *buf;
 269         struct object *object;
 270         int eaten;
 271
 272         if (no_data)
 273                 return;
 274
 275         if (is_null_oid(oid))
 276                 return;
 277
 278         object = lookup_object(the_repository, oid->hash);
 279         if (object && object->flags & SHOWN)
 280                 return;
 281
 282         if (anonymize) {
 283                 buf = anonymize_blob(&size);
 284                 object = (struct object *)lookup_blob(the_repository, oid);
 285                 eaten = 0;
 286         } else {
 287                 buf = read_object_file(oid, &type, &size);
 288                 if (!buf)
 289                         die("could not read blob %s", oid_to_hex(oid));
 290                 if (check_object_signature(oid, buf, size, type_name(type)) < 0)
 291                         die("oid mismatch in blob %s", oid_to_hex(oid));
 292                 object = parse_object_buffer(the_repository, oid, type,
 293                                              size, buf, &eaten);
 294         }
 295
 296         if (!object)
 297                 die("Could not read blob %s", oid_to_hex(oid));
 298
 299         mark_next_object(object);
 300
 301         printf("blob\nmark :%"PRIu32"\n", last_idnum);
 302         if (show_original_ids)
 303                 printf("original-oid %s\n", oid_to_hex(oid));
 304         printf("data %"PRIuMAX"\n", (uintmax_t)size);
 305         if (size && fwrite(buf, size, 1, stdout) != 1)
 306                 die_errno("could not write blob '%s'", oid_to_hex(oid));
 307         printf("\n");
 308
 309         show_progress();
 310
 311         object->flags |= SHOWN;
 312         if (!eaten)
 313                 free(buf);
 314 }
 315
 316 static int depth_first(const void *a_, const void *b_)
 317 {
 318         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
 319         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
 320         const char *name_a, *name_b;
 321         int len_a, len_b, len;
 322         int cmp;
 323
 324         name_a = a->one ? a->one->path : a->two->path;
 325         name_b = b->one ? b->one->path : b->two->path;
 326
 327         len_a = strlen(name_a);
 328         len_b = strlen(name_b);
 329         len = (len_a < len_b) ? len_a : len_b;
 330
 331         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
 332         cmp = memcmp(name_a, name_b, len);
 333         if (cmp)
 334                 return cmp;
 335         cmp = len_b - len_a;
 336         if (cmp)
 337                 return cmp;
 338         /*
 339          * Move 'R'ename entries last so that all references of the file
 340          * appear in the output before it is renamed (e.g., when a file
 341          * was copied and renamed in the same commit).
 342          */
 343         return (a->status == 'R') - (b->status == 'R');
 344 }
 345
 346 static void print_path_1(const char *path)
 347 {
 348         int need_quote = quote_c_style(path, NULL, NULL, 0);
 349         if (need_quote)
 350                 quote_c_style(path, NULL, stdout, 0);
 351         else if (strchr(path, ' '))
 352                 printf("\"%s\"", path);
 353         else
 354                 printf("%s", path);
 355 }
 356
 357 static void *anonymize_path_component(const void *path, size_t *len)
 358 {
 359         static int counter;
 360         struct strbuf out = STRBUF_INIT;
 361         strbuf_addf(&out, "path%d", counter++);
 362         return strbuf_detach(&out, len);
 363 }
 364
 365 static void print_path(const char *path)
 366 {
 367         if (!anonymize)
 368                 print_path_1(path);
 369         else {
 370                 static struct hashmap paths;
 371                 static struct strbuf anon = STRBUF_INIT;
 372
 373                 anonymize_path(&anon, path, &paths, anonymize_path_component);
 374                 print_path_1(anon.buf);
 375                 strbuf_reset(&anon);
 376         }
 377 }
 378
 379 static void *generate_fake_oid(const void *old, size_t *len)
 380 {
 381         static uint32_t counter = 1; /* avoid null oid */
 382         const unsigned hashsz = the_hash_algo->rawsz;
 383         unsigned char *out = xcalloc(hashsz, 1);
 384         put_be32(out + hashsz - 4, counter++);
 385         return out;
 386 }
 387
 388 static const struct object_id *anonymize_oid(const struct object_id *oid)
 389 {
 390         static struct hashmap objs;
 391         size_t len = the_hash_algo->rawsz;
 392         return anonymize_mem(&objs, generate_fake_oid, oid, &len);
 393 }
 394
 395 static void show_filemodify(struct diff_queue_struct *q,
 396                             struct diff_options *options, void *data)
 397 {
 398         int i;
 399         struct string_list *changed = data;
 400
 401         /*
 402          * Handle files below a directory first, in case they are all deleted
 403          * and the directory changes to a file or symlink.
 404          */
 405         QSORT(q->queue, q->nr, depth_first);
 406
 407         for (i = 0; i < q->nr; i++) {
 408                 struct diff_filespec *ospec = q->queue[i]->one;
 409                 struct diff_filespec *spec = q->queue[i]->two;
 410
 411                 switch (q->queue[i]->status) {
 412                 case DIFF_STATUS_DELETED:
 413                         printf("D ");
 414                         print_path(spec->path);
 415                         string_list_insert(changed, spec->path);
 416                         putchar('\n');
 417                         break;
 418
 419                 case DIFF_STATUS_COPIED:
 420                 case DIFF_STATUS_RENAMED:
 421                         /*
 422                          * If a change in the file corresponding to ospec->path
 423                          * has been observed, we cannot trust its contents
 424                          * because the diff is calculated based on the prior
 425                          * contents, not the current contents.  So, declare a
 426                          * copy or rename only if there was no change observed.
 427                          */
 428                         if (!string_list_has_string(changed, ospec->path)) {
 429                                 printf("%c ", q->queue[i]->status);
 430                                 print_path(ospec->path);
 431                                 putchar(' ');
 432                                 print_path(spec->path);
 433                                 string_list_insert(changed, spec->path);
 434                                 putchar('\n');
 435
 436                                 if (oideq(&ospec->oid, &spec->oid) &&
 437                                     ospec->mode == spec->mode)
 438                                         break;
 439                         }
 440                         /* fallthrough */
 441
 442                 case DIFF_STATUS_TYPE_CHANGED:
 443                 case DIFF_STATUS_MODIFIED:
 444                 case DIFF_STATUS_ADDED:
 445                         /*
 446                          * Links refer to objects in another repositories;
 447                          * output the SHA-1 verbatim.
 448                          */
 449                         if (no_data || S_ISGITLINK(spec->mode))
 450                                 printf("M %06o %s ", spec->mode,
 451                                        oid_to_hex(anonymize ?
 452                                                   anonymize_oid(&spec->oid) :
 453                                                   &spec->oid));
 454                         else {
 455                                 struct object *object = lookup_object(the_repository,
 456                                                                       spec->oid.hash);
 457                                 printf("M %06o :%d ", spec->mode,
 458                                        get_object_mark(object));
 459                         }
 460                         print_path(spec->path);
 461                         string_list_insert(changed, spec->path);
 462                         putchar('\n');
 463                         break;
 464
 465                 default:
 466                         die("Unexpected comparison status '%c' for %s, %s",
 467                                 q->queue[i]->status,
 468                                 ospec->path ? ospec->path : "none",
 469                                 spec->path ? spec->path : "none");
 470                 }
 471         }
 472 }
 473
 474 static const char *find_encoding(const char *begin, const char *end)
 475 {
 476         const char *needle = "\nencoding ";
 477         char *bol, *eol;
 478
 479         bol = memmem(begin, end ? end - begin : strlen(begin),
 480                      needle, strlen(needle));
 481         if (!bol)
 482                 return NULL;
 483         bol += strlen(needle);
 484         eol = strchrnul(bol, '\n');
 485         *eol = '\0';
 486         return bol;
 487 }
 488
 489 static void *anonymize_ref_component(const void *old, size_t *len)
 490 {
 491         static int counter;
 492         struct strbuf out = STRBUF_INIT;
 493         strbuf_addf(&out, "ref%d", counter++);
 494         return strbuf_detach(&out, len);
 495 }
 496
 497 static const char *anonymize_refname(const char *refname)
 498 {
 499         /*
 500          * If any of these prefixes is found, we will leave it intact
 501          * so that tags remain tags and so forth.
 502          */
 503         static const char *prefixes[] = {
 504                 "refs/heads/",
 505                 "refs/tags/",
 506                 "refs/remotes/",
 507                 "refs/"
 508         };
 509         static struct hashmap refs;
 510         static struct strbuf anon = STRBUF_INIT;
 511         int i;
 512
 513         /*
 514          * We also leave "master" as a special case, since it does not reveal
 515          * anything interesting.
 516          */
 517         if (!strcmp(refname, "refs/heads/master"))
 518                 return refname;
 519
 520         strbuf_reset(&anon);
 521         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
 522                 if (skip_prefix(refname, prefixes[i], &refname)) {
 523                         strbuf_addstr(&anon, prefixes[i]);
 524                         break;
 525                 }
 526         }
 527
 528         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
 529         return anon.buf;
 530 }
 531
 532 /*
 533  * We do not even bother to cache commit messages, as they are unlikely
 534  * to be repeated verbatim, and it is not that interesting when they are.
 535  */
 536 static char *anonymize_commit_message(const char *old)
 537 {
 538         static int counter;
 539         return xstrfmt("subject %d\n\nbody\n", counter++);
 540 }
 541
 542 static struct hashmap idents;
 543 static void *anonymize_ident(const void *old, size_t *len)
 544 {
 545         static int counter;
 546         struct strbuf out = STRBUF_INIT;
 547         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
 548         counter++;
 549         return strbuf_detach(&out, len);
 550 }
 551
 552 /*
 553  * Our strategy here is to anonymize the names and email addresses,
 554  * but keep timestamps intact, as they influence things like traversal
 555  * order (and by themselves should not be too revealing).
 556  */
 557 static void anonymize_ident_line(const char **beg, const char **end)
 558 {
 559         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
 560         static unsigned which_buffer;
 561
 562         struct strbuf *out;
 563         struct ident_split split;
 564         const char *end_of_header;
 565
 566         out = &buffers[which_buffer++];
 567         which_buffer %= ARRAY_SIZE(buffers);
 568         strbuf_reset(out);
 569
 570         /* skip "committer", "author", "tagger", etc */
 571         end_of_header = strchr(*beg, ' ');
 572         if (!end_of_header)
 573                 BUG("malformed line fed to anonymize_ident_line: %.*s",
 574                     (int)(*end - *beg), *beg);
 575         end_of_header++;
 576         strbuf_add(out, *beg, end_of_header - *beg);
 577
 578         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
 579             split.date_begin) {
 580                 const char *ident;
 581                 size_t len;
 582
 583                 len = split.mail_end - split.name_begin;
 584                 ident = anonymize_mem(&idents, anonymize_ident,
 585                                       split.name_begin, &len);
 586                 strbuf_add(out, ident, len);
 587                 strbuf_addch(out, ' ');
 588                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
 589         } else {
 590                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
 591         }
 592
 593         *beg = out->buf;
 594         *end = out->buf + out->len;
 595 }
 596
 597 static void handle_commit(struct commit *commit, struct rev_info *rev,
 598                           struct string_list *paths_of_changed_objects)
 599 {
 600         int saved_output_format = rev->diffopt.output_format;
 601         const char *commit_buffer;
 602         const char *author, *author_end, *committer, *committer_end;
 603         const char *encoding, *message;
 604         char *reencoded = NULL;
 605         struct commit_list *p;
 606         const char *refname;
 607         int i;
 608
 609         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
 610
 611         parse_commit_or_die(commit);
 612         commit_buffer = get_commit_buffer(commit, NULL);
 613         author = strstr(commit_buffer, "\nauthor ");
 614         if (!author)
 615                 die("could not find author in commit %s",
 616                     oid_to_hex(&commit->object.oid));
 617         author++;
 618         author_end = strchrnul(author, '\n');
 619         committer = strstr(author_end, "\ncommitter ");
 620         if (!committer)
 621                 die("could not find committer in commit %s",
 622                     oid_to_hex(&commit->object.oid));
 623         committer++;
 624         committer_end = strchrnul(committer, '\n');
 625         message = strstr(committer_end, "\n\n");
 626         encoding = find_encoding(committer_end, message);
 627         if (message)
 628                 message += 2;
 629
 630         if (commit->parents &&
 631             (get_object_mark(&commit->parents->item->object) != 0 ||
 632              reference_excluded_commits) &&
 633             !full_tree) {
 634                 parse_commit_or_die(commit->parents->item);
 635                 diff_tree_oid(get_commit_tree_oid(commit->parents->item),
 636                               get_commit_tree_oid(commit), "", &rev->diffopt);
 637         }
 638         else
 639                 diff_root_tree_oid(get_commit_tree_oid(commit),
 640                                    "", &rev->diffopt);
 641
 642         /* Export the referenced blobs, and remember the marks. */
 643         for (i = 0; i < diff_queued_diff.nr; i++)
 644                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
 645                         export_blob(&diff_queued_diff.queue[i]->two->oid);
 646
 647         refname = *revision_sources_at(&revision_sources, commit);
 648         /*
 649          * FIXME: string_list_remove() below for each ref is overall
 650          * O(N^2).  Compared to a history walk and diffing trees, this is
 651          * just lost in the noise in practice.  However, theoretically a
 652          * repo may have enough refs for this to become slow.
 653          */
 654         string_list_remove(&extra_refs, refname, 0);
 655         if (anonymize) {
 656                 refname = anonymize_refname(refname);
 657                 anonymize_ident_line(&committer, &committer_end);
 658                 anonymize_ident_line(&author, &author_end);
 659         }
 660
 661         mark_next_object(&commit->object);
 662         if (anonymize) {
 663                 reencoded = anonymize_commit_message(message);
 664         } else if (encoding) {
 665                 switch(reencode_mode) {
 666                 case REENCODE_YES:
 667                         reencoded = reencode_string(message, "UTF-8", encoding);
 668                         break;
 669                 case REENCODE_NO:
 670                         break;
 671                 case REENCODE_ABORT:
 672                         die("Encountered commit-specific encoding %s in commit "
 673                             "%s; use --reencode=[yes|no] to handle it",
 674                             encoding, oid_to_hex(&commit->object.oid));
 675                 }
 676         }
 677         if (!commit->parents)
 678                 printf("reset %s\n", refname);
 679         printf("commit %s\nmark :%"PRIu32"\n", refname, last_idnum);
 680         if (show_original_ids)
 681                 printf("original-oid %s\n", oid_to_hex(&commit->object.oid));
 682         printf("%.*s\n%.*s\n",
 683                (int)(author_end - author), author,
 684                (int)(committer_end - committer), committer);
 685         if (!reencoded && encoding)
 686                 printf("encoding %s\n", encoding);
 687         printf("data %u\n%s",
 688                (unsigned)(reencoded
 689                           ? strlen(reencoded) : message
 690                           ? strlen(message) : 0),
 691                reencoded ? reencoded : message ? message : "");
 692         free(reencoded);
 693         unuse_commit_buffer(commit, commit_buffer);
 694
 695         for (i = 0, p = commit->parents; p; p = p->next) {
 696                 struct object *obj = &p->item->object;
 697                 int mark = get_object_mark(obj);
 698
 699                 if (!mark && !reference_excluded_commits)
 700                         continue;
 701                 if (i == 0)
 702                         printf("from ");
 703                 else
 704                         printf("merge ");
 705                 if (mark)
 706                         printf(":%d\n", mark);
 707                 else
 708                         printf("%s\n", oid_to_hex(anonymize ?
 709                                                   anonymize_oid(&obj->oid) :
 710                                                   &obj->oid));
 711                 i++;
 712         }
 713
 714         if (full_tree)
 715                 printf("deleteall\n");
 716         log_tree_diff_flush(rev);
 717         string_list_clear(paths_of_changed_objects, 0);
 718         rev->diffopt.output_format = saved_output_format;
 719
 720         printf("\n");
 721
 722         show_progress();
 723 }
 724
 725 static void *anonymize_tag(const void *old, size_t *len)
 726 {
 727         static int counter;
 728         struct strbuf out = STRBUF_INIT;
 729         strbuf_addf(&out, "tag message %d", counter++);
 730         return strbuf_detach(&out, len);
 731 }
 732
 733 static void handle_tail(struct object_array *commits, struct rev_info *revs,
 734                         struct string_list *paths_of_changed_objects)
 735 {
 736         struct commit *commit;
 737         while (commits->nr) {
 738                 commit = (struct commit *)object_array_pop(commits);
 739                 if (has_unshown_parent(commit)) {
 740                         /* Queue again, to be handled later */
 741                         add_object_array(&commit->object, NULL, commits);
 742                         return;
 743                 }
 744                 handle_commit(commit, revs, paths_of_changed_objects);
 745         }
 746 }
 747
 748 static void handle_tag(const char *name, struct tag *tag)
 749 {
 750         unsigned long size;
 751         enum object_type type;
 752         char *buf;
 753         const char *tagger, *tagger_end, *message;
 754         size_t message_size = 0;
 755         struct object *tagged;
 756         int tagged_mark;
 757         struct commit *p;
 758
 759         /* Trees have no identifier in fast-export output, thus we have no way
 760          * to output tags of trees, tags of tags of trees, etc.  Simply omit
 761          * such tags.
 762          */
 763         tagged = tag->tagged;
 764         while (tagged->type == OBJ_TAG) {
 765                 tagged = ((struct tag *)tagged)->tagged;
 766         }
 767         if (tagged->type == OBJ_TREE) {
 768                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
 769                         oid_to_hex(&tag->object.oid));
 770                 return;
 771         }
 772
 773         buf = read_object_file(&tag->object.oid, &type, &size);
 774         if (!buf)
 775                 die("could not read tag %s", oid_to_hex(&tag->object.oid));
 776         message = memmem(buf, size, "\n\n", 2);
 777         if (message) {
 778                 message += 2;
 779                 message_size = strlen(message);
 780         }
 781         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
 782         if (!tagger) {
 783                 if (fake_missing_tagger)
 784                         tagger = "tagger Unspecified Tagger "
 785                                 "<unspecified-tagger> 0 +0000";
 786                 else
 787                         tagger = "";
 788                 tagger_end = tagger + strlen(tagger);
 789         } else {
 790                 tagger++;
 791                 tagger_end = strchrnul(tagger, '\n');
 792                 if (anonymize)
 793                         anonymize_ident_line(&tagger, &tagger_end);
 794         }
 795
 796         if (anonymize) {
 797                 name = anonymize_refname(name);
 798                 if (message) {
 799                         static struct hashmap tags;
 800                         message = anonymize_mem(&tags, anonymize_tag,
 801                                                 message, &message_size);
 802                 }
 803         }
 804
 805         /* handle signed tags */
 806         if (message) {
 807                 const char *signature = strstr(message,
 808                                                "\n-----BEGIN PGP SIGNATURE-----\n");
 809                 if (signature)
 810                         switch(signed_tag_mode) {
 811                         case SIGNED_TAG_ABORT:
 812                                 die("encountered signed tag %s; use "
 813                                     "--signed-tags=<mode> to handle it",
 814                                     oid_to_hex(&tag->object.oid));
 815                         case WARN:
 816                                 warning("exporting signed tag %s",
 817                                         oid_to_hex(&tag->object.oid));
 818                                 /* fallthru */
 819                         case VERBATIM:
 820                                 break;
 821                         case WARN_STRIP:
 822                                 warning("stripping signature from tag %s",
 823                                         oid_to_hex(&tag->object.oid));
 824                                 /* fallthru */
 825                         case STRIP:
 826                                 message_size = signature + 1 - message;
 827                                 break;
 828                         }
 829         }
 830
 831         /* handle tag->tagged having been filtered out due to paths specified */
 832         tagged = tag->tagged;
 833         tagged_mark = get_object_mark(tagged);
 834         if (!tagged_mark) {
 835                 switch(tag_of_filtered_mode) {
 836                 case TAG_FILTERING_ABORT:
 837                         die("tag %s tags unexported object; use "
 838                             "--tag-of-filtered-object=<mode> to handle it",
 839                             oid_to_hex(&tag->object.oid));
 840                 case DROP:
 841                         /* Ignore this tag altogether */
 842                         free(buf);
 843                         return;
 844                 case REWRITE:
 845                         if (tagged->type != OBJ_COMMIT) {
 846                                 die("tag %s tags unexported %s!",
 847                                     oid_to_hex(&tag->object.oid),
 848                                     type_name(tagged->type));
 849                         }
 850                         p = rewrite_commit((struct commit *)tagged);
 851                         if (!p) {
 852                                 printf("reset %s\nfrom %s\n\n",
 853                                        name, oid_to_hex(&null_oid));
 854                                 free(buf);
 855                                 return;
 856                         }
 857                         tagged_mark = get_object_mark(&p->object);
 858                 }
 859         }
 860
 861         if (starts_with(name, "refs/tags/"))
 862                 name += 10;
 863         printf("tag %s\nfrom :%d\n", name, tagged_mark);
 864         if (show_original_ids)
 865                 printf("original-oid %s\n", oid_to_hex(&tag->object.oid));
 866         printf("%.*s%sdata %d\n%.*s\n",
 867                (int)(tagger_end - tagger), tagger,
 868                tagger == tagger_end ? "" : "\n",
 869                (int)message_size, (int)message_size, message ? message : "");
 870         free(buf);
 871 }
 872
 873 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
 874 {
 875         switch (e->item->type) {
 876         case OBJ_COMMIT:
 877                 return (struct commit *)e->item;
 878         case OBJ_TAG: {
 879                 struct tag *tag = (struct tag *)e->item;
 880
 881                 /* handle nested tags */
 882                 while (tag && tag->object.type == OBJ_TAG) {
 883                         parse_object(the_repository, &tag->object.oid);
 884                         string_list_append(&tag_refs, full_name)->util = tag;
 885                         tag = (struct tag *)tag->tagged;
 886                 }
 887                 if (!tag)
 888                         die("Tag %s points nowhere?", e->name);
 889                 return (struct commit *)tag;
 890                 break;
 891         }
 892         default:
 893                 return NULL;
 894         }
 895 }
 896
 897 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 898 {
 899         int i;
 900
 901         for (i = 0; i < info->nr; i++) {
 902                 struct rev_cmdline_entry *e = info->rev + i;
 903                 struct object_id oid;
 904                 struct commit *commit;
 905                 char *full_name;
 906
 907                 if (e->flags & UNINTERESTING)
 908                         continue;
 909
 910                 if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 911                         continue;
 912
 913                 if (refspecs.nr) {
 914                         char *private;
 915                         private = apply_refspecs(&refspecs, full_name);
 916                         if (private) {
 917                                 free(full_name);
 918                                 full_name = private;
 919                         }
 920                 }
 921
 922                 commit = get_commit(e, full_name);
 923                 if (!commit) {
 924                         warning("%s: Unexpected object of type %s, skipping.",
 925                                 e->name,
 926                                 type_name(e->item->type));
 927                         continue;
 928                 }
 929
 930                 switch(commit->object.type) {
 931                 case OBJ_COMMIT:
 932                         break;
 933                 case OBJ_BLOB:
 934                         export_blob(&commit->object.oid);
 935                         continue;
 936                 default: /* OBJ_TAG (nested tags) is already handled */
 937                         warning("Tag points to object of unexpected type %s, skipping.",
 938                                 type_name(commit->object.type));
 939                         continue;
 940                 }
 941
 942                 /*
 943                  * Make sure this ref gets properly updated eventually, whether
 944                  * through a commit or manually at the end.
 945                  */
 946                 if (e->item->type != OBJ_TAG)
 947                         string_list_append(&extra_refs, full_name)->util = commit;
 948
 949                 if (!*revision_sources_at(&revision_sources, commit))
 950                         *revision_sources_at(&revision_sources, commit) = full_name;
 951         }
 952
 953         string_list_sort(&extra_refs);
 954         string_list_remove_duplicates(&extra_refs, 0);
 955 }
 956
 957 static void handle_tags_and_duplicates(struct string_list *extras)
 958 {
 959         struct commit *commit;
 960         int i;
 961
 962         for (i = extras->nr - 1; i >= 0; i--) {
 963                 const char *name = extras->items[i].string;
 964                 struct object *object = extras->items[i].util;
 965                 int mark;
 966
 967                 switch (object->type) {
 968                 case OBJ_TAG:
 969                         handle_tag(name, (struct tag *)object);
 970                         break;
 971                 case OBJ_COMMIT:
 972                         if (anonymize)
 973                                 name = anonymize_refname(name);
 974                         /* create refs pointing to already seen commits */
 975                         commit = rewrite_commit((struct commit *)object);
 976                         if (!commit) {
 977                                 /*
 978                                  * Neither this object nor any of its
 979                                  * ancestors touch any relevant paths, so
 980                                  * it has been filtered to nothing.  Delete
 981                                  * it.
 982                                  */
 983                                 printf("reset %s\nfrom %s\n\n",
 984                                        name, oid_to_hex(&null_oid));
 985                                 continue;
 986                         }
 987
 988                         mark = get_object_mark(&commit->object);
 989                         if (!mark) {
 990                                 /*
 991                                  * Getting here means we have a commit which
 992                                  * was excluded by a negative refspec (e.g.
 993                                  * fast-export ^master master).  If we are
 994                                  * referencing excluded commits, set the ref
 995                                  * to the exact commit.  Otherwise, the user
 996                                  * wants the branch exported but every commit
 997                                  * in its history to be deleted, which basically
 998                                  * just means deletion of the ref.
 999                                  */
1000                                 if (!reference_excluded_commits) {
1001                                         /* delete the ref */
1002                                         printf("reset %s\nfrom %s\n\n",
1003                                                name, oid_to_hex(&null_oid));
1004                                         continue;
1005                                 }
1006                                 /* set ref to commit using oid, not mark */
1007                                 printf("reset %s\nfrom %s\n\n", name,
1008                                        oid_to_hex(&commit->object.oid));
1009                                 continue;
1010                         }
1011
1012                         printf("reset %s\nfrom :%d\n\n", name, mark
1013                                );
1014                         show_progress();
1015                         break;
1016                 }
1017         }
1018 }
1019
1020 static void export_marks(char *file)
1021 {
1022         unsigned int i;
1023         uint32_t mark;
1024         struct decoration_entry *deco = idnums.entries;
1025         FILE *f;
1026         int e = 0;
1027
1028         f = fopen_for_writing(file);
1029         if (!f)
1030                 die_errno("Unable to open marks file %s for writing.", file);
1031
1032         for (i = 0; i < idnums.size; i++) {
1033                 if (deco->base && deco->base->type == 1) {
1034                         mark = ptr_to_mark(deco->decoration);
1035                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
1036                                 oid_to_hex(&deco->base->oid)) < 0) {
1037                             e = 1;
1038                             break;
1039                         }
1040                 }
1041                 deco++;
1042         }
1043
1044         e |= ferror(f);
1045         e |= fclose(f);
1046         if (e)
1047                 error("Unable to write marks file %s.", file);
1048 }
1049
1050 static void import_marks(char *input_file)
1051 {
1052         char line[512];
1053         FILE *f = xfopen(input_file, "r");
1054
1055         while (fgets(line, sizeof(line), f)) {
1056                 uint32_t mark;
1057                 char *line_end, *mark_end;
1058                 struct object_id oid;
1059                 struct object *object;
1060                 struct commit *commit;
1061                 enum object_type type;
1062
1063                 line_end = strchr(line, '\n');
1064                 if (line[0] != ':' || !line_end)
1065                         die("corrupt mark line: %s", line);
1066                 *line_end = '\0';
1067
1068                 mark = strtoumax(line + 1, &mark_end, 10);
1069                 if (!mark || mark_end == line + 1
1070                         || *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
1071                         die("corrupt mark line: %s", line);
1072
1073                 if (last_idnum < mark)
1074                         last_idnum = mark;
1075
1076                 type = oid_object_info(the_repository, &oid, NULL);
1077                 if (type < 0)
1078                         die("object not found: %s", oid_to_hex(&oid));
1079
1080                 if (type != OBJ_COMMIT)
1081                         /* only commits */
1082                         continue;
1083
1084                 commit = lookup_commit(the_repository, &oid);
1085                 if (!commit)
1086                         die("not a commit? can't happen: %s", oid_to_hex(&oid));
1087
1088                 object = &commit->object;
1089
1090                 if (object->flags & SHOWN)
1091                         error("Object %s already has a mark", oid_to_hex(&oid));
1092
1093                 mark_object(object, mark);
1094
1095                 object->flags |= SHOWN;
1096         }
1097         fclose(f);
1098 }
1099
1100 static void handle_deletes(void)
1101 {
1102         int i;
1103         for (i = 0; i < refspecs.nr; i++) {
1104                 struct refspec_item *refspec = &refspecs.items[i];
1105                 if (*refspec->src)
1106                         continue;
1107
1108                 printf("reset %s\nfrom %s\n\n",
1109                                 refspec->dst, oid_to_hex(&null_oid));
1110         }
1111 }
1112
1113 int cmd_fast_export(int argc, const char **argv, const char *prefix)
1114 {
1115         struct rev_info revs;
1116         struct object_array commits = OBJECT_ARRAY_INIT;
1117         struct commit *commit;
1118         char *export_filename = NULL, *import_filename = NULL;
1119         uint32_t lastimportid;
1120         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
1121         struct string_list paths_of_changed_objects = STRING_LIST_INIT_DUP;
1122         struct option options[] = {
1123                 OPT_INTEGER(0, "progress", &progress,
1124                             N_("show progress after <n> objects")),
1125                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
1126                              N_("select handling of signed tags"),
1127                              parse_opt_signed_tag_mode),
1128                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
1129                              N_("select handling of tags that tag filtered objects"),
1130                              parse_opt_tag_of_filtered_mode),
1131                 OPT_CALLBACK(0, "reencode", &reencode_mode, N_("mode"),
1132                              N_("select handling of commit messages in an alternate encoding"),
1133                              parse_opt_reencode_mode),
1134                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
1135                              N_("Dump marks to this file")),
1136                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
1137                              N_("Import marks from this file")),
1138                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
1139                          N_("Fake a tagger when tags lack one")),
1140                 OPT_BOOL(0, "full-tree", &full_tree,
1141                          N_("Output full tree for each commit")),
1142                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
1143                              N_("Use the done feature to terminate the stream")),
1144                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
1145                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
1146                              N_("Apply refspec to exported refs")),
1147                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1148                 OPT_BOOL(0, "reference-excluded-parents",
1149                          &reference_excluded_commits, N_("Reference parents which are not in fast-export stream by object id")),
1150                 OPT_BOOL(0, "show-original-ids", &show_original_ids,
1151                             N_("Show original object ids of blobs/commits")),
1152
1153                 OPT_END()
1154         };
1155
1156         if (argc == 1)
1157                 usage_with_options (fast_export_usage, options);
1158
1159         /* we handle encodings */
1160         git_config(git_default_config, NULL);
1161
1162         repo_init_revisions(the_repository, &revs, prefix);
1163         init_revision_sources(&revision_sources);
1164         revs.topo_order = 1;
1165         revs.sources = &revision_sources;
1166         revs.rewrite_parents = 1;
1167         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1168                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1169         argc = setup_revisions(argc, argv, &revs, NULL);
1170         if (argc > 1)
1171                 usage_with_options (fast_export_usage, options);
1172
1173         if (refspecs_list.nr) {
1174                 int i;
1175
1176                 for (i = 0; i < refspecs_list.nr; i++)
1177                         refspec_append(&refspecs, refspecs_list.items[i].string);
1178
1179                 string_list_clear(&refspecs_list, 1);
1180         }
1181
1182         if (use_done_feature)
1183                 printf("feature done\n");
1184
1185         if (import_filename)
1186                 import_marks(import_filename);
1187         lastimportid = last_idnum;
1188
1189         if (import_filename && revs.prune_data.nr)
1190                 full_tree = 1;
1191
1192         get_tags_and_duplicates(&revs.cmdline);
1193
1194         if (prepare_revision_walk(&revs))
1195                 die("revision walk setup failed");
1196         revs.diffopt.format_callback = show_filemodify;
1197         revs.diffopt.format_callback_data = &paths_of_changed_objects;
1198         revs.diffopt.flags.recursive = 1;
1199         while ((commit = get_revision(&revs))) {
1200                 if (has_unshown_parent(commit)) {
1201                         add_object_array(&commit->object, NULL, &commits);
1202                 }
1203                 else {
1204                         handle_commit(commit, &revs, &paths_of_changed_objects);
1205                         handle_tail(&commits, &revs, &paths_of_changed_objects);
1206                 }
1207         }
1208
1209         handle_tags_and_duplicates(&extra_refs);
1210         handle_tags_and_duplicates(&tag_refs);
1211         handle_deletes();
1212
1213         if (export_filename && lastimportid != last_idnum)
1214                 export_marks(export_filename);
1215
1216         if (use_done_feature)
1217                 printf("done\n");
1218
1219         refspec_clear(&refspecs);
1220
1221         return 0;
1222 }