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 "commit.h"
  12 #include "object.h"
  13 #include "tag.h"
  14 #include "diff.h"
  15 #include "diffcore.h"
  16 #include "log-tree.h"
  17 #include "revision.h"
  18 #include "decorate.h"
  19 #include "string-list.h"
  20 #include "utf8.h"
  21 #include "parse-options.h"
  22 #include "quote.h"
  23 #include "remote.h"
  24 #include "blob.h"
  25 #include "commit-slab.h"
  26
  27 static const char *fast_export_usage[] = {
  28         N_("git fast-export [rev-list-opts]"),
  29         NULL
  30 };
  31
  32 static int progress;
  33 static enum { ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = ABORT;
  34 static enum { ERROR, DROP, REWRITE } tag_of_filtered_mode = ERROR;
  35 static int fake_missing_tagger;
  36 static int use_done_feature;
  37 static int no_data;
  38 static int full_tree;
  39 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
  40 static struct refspec refspecs = REFSPEC_INIT_FETCH;
  41 static int anonymize;
  42 static struct revision_sources revision_sources;
  43
  44 static int parse_opt_signed_tag_mode(const struct option *opt,
  45                                      const char *arg, int unset)
  46 {
  47         if (unset || !strcmp(arg, "abort"))
  48                 signed_tag_mode = ABORT;
  49         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
  50                 signed_tag_mode = VERBATIM;
  51         else if (!strcmp(arg, "warn"))
  52                 signed_tag_mode = WARN;
  53         else if (!strcmp(arg, "warn-strip"))
  54                 signed_tag_mode = WARN_STRIP;
  55         else if (!strcmp(arg, "strip"))
  56                 signed_tag_mode = STRIP;
  57         else
  58                 return error("Unknown signed-tags mode: %s", arg);
  59         return 0;
  60 }
  61
  62 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
  63                                           const char *arg, int unset)
  64 {
  65         if (unset || !strcmp(arg, "abort"))
  66                 tag_of_filtered_mode = ERROR;
  67         else if (!strcmp(arg, "drop"))
  68                 tag_of_filtered_mode = DROP;
  69         else if (!strcmp(arg, "rewrite"))
  70                 tag_of_filtered_mode = REWRITE;
  71         else
  72                 return error("Unknown tag-of-filtered mode: %s", arg);
  73         return 0;
  74 }
  75
  76 static struct decoration idnums;
  77 static uint32_t last_idnum;
  78
  79 static int has_unshown_parent(struct commit *commit)
  80 {
  81         struct commit_list *parent;
  82
  83         for (parent = commit->parents; parent; parent = parent->next)
  84                 if (!(parent->item->object.flags & SHOWN) &&
  85                     !(parent->item->object.flags & UNINTERESTING))
  86                         return 1;
  87         return 0;
  88 }
  89
  90 struct anonymized_entry {
  91         struct hashmap_entry hash;
  92         const char *orig;
  93         size_t orig_len;
  94         const char *anon;
  95         size_t anon_len;
  96 };
  97
  98 static int anonymized_entry_cmp(const void *unused_cmp_data,
  99                                 const void *va, const void *vb,
 100                                 const void *unused_keydata)
 101 {
 102         const struct anonymized_entry *a = va, *b = vb;
 103         return a->orig_len != b->orig_len ||
 104                 memcmp(a->orig, b->orig, a->orig_len);
 105 }
 106
 107 /*
 108  * Basically keep a cache of X->Y so that we can repeatedly replace
 109  * the same anonymized string with another. The actual generation
 110  * is farmed out to the generate function.
 111  */
 112 static const void *anonymize_mem(struct hashmap *map,
 113                                  void *(*generate)(const void *, size_t *),
 114                                  const void *orig, size_t *len)
 115 {
 116         struct anonymized_entry key, *ret;
 117
 118         if (!map->cmpfn)
 119                 hashmap_init(map, anonymized_entry_cmp, NULL, 0);
 120
 121         hashmap_entry_init(&key, memhash(orig, *len));
 122         key.orig = orig;
 123         key.orig_len = *len;
 124         ret = hashmap_get(map, &key, NULL);
 125
 126         if (!ret) {
 127                 ret = xmalloc(sizeof(*ret));
 128                 hashmap_entry_init(&ret->hash, key.hash.hash);
 129                 ret->orig = xstrdup(orig);
 130                 ret->orig_len = *len;
 131                 ret->anon = generate(orig, len);
 132                 ret->anon_len = *len;
 133                 hashmap_put(map, ret);
 134         }
 135
 136         *len = ret->anon_len;
 137         return ret->anon;
 138 }
 139
 140 /*
 141  * We anonymize each component of a path individually,
 142  * so that paths a/b and a/c will share a common root.
 143  * The paths are cached via anonymize_mem so that repeated
 144  * lookups for "a" will yield the same value.
 145  */
 146 static void anonymize_path(struct strbuf *out, const char *path,
 147                            struct hashmap *map,
 148                            void *(*generate)(const void *, size_t *))
 149 {
 150         while (*path) {
 151                 const char *end_of_component = strchrnul(path, '/');
 152                 size_t len = end_of_component - path;
 153                 const char *c = anonymize_mem(map, generate, path, &len);
 154                 strbuf_add(out, c, len);
 155                 path = end_of_component;
 156                 if (*path)
 157                         strbuf_addch(out, *path++);
 158         }
 159 }
 160
 161 static inline void *mark_to_ptr(uint32_t mark)
 162 {
 163         return (void *)(uintptr_t)mark;
 164 }
 165
 166 static inline uint32_t ptr_to_mark(void * mark)
 167 {
 168         return (uint32_t)(uintptr_t)mark;
 169 }
 170
 171 static inline void mark_object(struct object *object, uint32_t mark)
 172 {
 173         add_decoration(&idnums, object, mark_to_ptr(mark));
 174 }
 175
 176 static inline void mark_next_object(struct object *object)
 177 {
 178         mark_object(object, ++last_idnum);
 179 }
 180
 181 static int get_object_mark(struct object *object)
 182 {
 183         void *decoration = lookup_decoration(&idnums, object);
 184         if (!decoration)
 185                 return 0;
 186         return ptr_to_mark(decoration);
 187 }
 188
 189 static void show_progress(void)
 190 {
 191         static int counter = 0;
 192         if (!progress)
 193                 return;
 194         if ((++counter % progress) == 0)
 195                 printf("progress %d objects\n", counter);
 196 }
 197
 198 /*
 199  * Ideally we would want some transformation of the blob data here
 200  * that is unreversible, but would still be the same size and have
 201  * the same data relationship to other blobs (so that we get the same
 202  * delta and packing behavior as the original). But the first and last
 203  * requirements there are probably mutually exclusive, so let's take
 204  * the easy way out for now, and just generate arbitrary content.
 205  *
 206  * There's no need to cache this result with anonymize_mem, since
 207  * we already handle blob content caching with marks.
 208  */
 209 static char *anonymize_blob(unsigned long *size)
 210 {
 211         static int counter;
 212         struct strbuf out = STRBUF_INIT;
 213         strbuf_addf(&out, "anonymous blob %d", counter++);
 214         *size = out.len;
 215         return strbuf_detach(&out, NULL);
 216 }
 217
 218 static void export_blob(const struct object_id *oid)
 219 {
 220         unsigned long size;
 221         enum object_type type;
 222         char *buf;
 223         struct object *object;
 224         int eaten;
 225
 226         if (no_data)
 227                 return;
 228
 229         if (is_null_oid(oid))
 230                 return;
 231
 232         object = lookup_object(oid->hash);
 233         if (object && object->flags & SHOWN)
 234                 return;
 235
 236         if (anonymize) {
 237                 buf = anonymize_blob(&size);
 238                 object = (struct object *)lookup_blob(oid);
 239                 eaten = 0;
 240         } else {
 241                 buf = read_object_file(oid, &type, &size);
 242                 if (!buf)
 243                         die ("Could not read blob %s", oid_to_hex(oid));
 244                 if (check_object_signature(oid, buf, size, type_name(type)) < 0)
 245                         die("sha1 mismatch in blob %s", oid_to_hex(oid));
 246                 object = parse_object_buffer(oid, type, size, buf, &eaten);
 247         }
 248
 249         if (!object)
 250                 die("Could not read blob %s", oid_to_hex(oid));
 251
 252         mark_next_object(object);
 253
 254         printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
 255         if (size && fwrite(buf, size, 1, stdout) != 1)
 256                 die_errno ("Could not write blob '%s'", oid_to_hex(oid));
 257         printf("\n");
 258
 259         show_progress();
 260
 261         object->flags |= SHOWN;
 262         if (!eaten)
 263                 free(buf);
 264 }
 265
 266 static int depth_first(const void *a_, const void *b_)
 267 {
 268         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
 269         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
 270         const char *name_a, *name_b;
 271         int len_a, len_b, len;
 272         int cmp;
 273
 274         name_a = a->one ? a->one->path : a->two->path;
 275         name_b = b->one ? b->one->path : b->two->path;
 276
 277         len_a = strlen(name_a);
 278         len_b = strlen(name_b);
 279         len = (len_a < len_b) ? len_a : len_b;
 280
 281         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
 282         cmp = memcmp(name_a, name_b, len);
 283         if (cmp)
 284                 return cmp;
 285         cmp = len_b - len_a;
 286         if (cmp)
 287                 return cmp;
 288         /*
 289          * Move 'R'ename entries last so that all references of the file
 290          * appear in the output before it is renamed (e.g., when a file
 291          * was copied and renamed in the same commit).
 292          */
 293         return (a->status == 'R') - (b->status == 'R');
 294 }
 295
 296 static void print_path_1(const char *path)
 297 {
 298         int need_quote = quote_c_style(path, NULL, NULL, 0);
 299         if (need_quote)
 300                 quote_c_style(path, NULL, stdout, 0);
 301         else if (strchr(path, ' '))
 302                 printf("\"%s\"", path);
 303         else
 304                 printf("%s", path);
 305 }
 306
 307 static void *anonymize_path_component(const void *path, size_t *len)
 308 {
 309         static int counter;
 310         struct strbuf out = STRBUF_INIT;
 311         strbuf_addf(&out, "path%d", counter++);
 312         return strbuf_detach(&out, len);
 313 }
 314
 315 static void print_path(const char *path)
 316 {
 317         if (!anonymize)
 318                 print_path_1(path);
 319         else {
 320                 static struct hashmap paths;
 321                 static struct strbuf anon = STRBUF_INIT;
 322
 323                 anonymize_path(&anon, path, &paths, anonymize_path_component);
 324                 print_path_1(anon.buf);
 325                 strbuf_reset(&anon);
 326         }
 327 }
 328
 329 static void *generate_fake_oid(const void *old, size_t *len)
 330 {
 331         static uint32_t counter = 1; /* avoid null sha1 */
 332         unsigned char *out = xcalloc(GIT_SHA1_RAWSZ, 1);
 333         put_be32(out + GIT_SHA1_RAWSZ - 4, counter++);
 334         return out;
 335 }
 336
 337 static const unsigned char *anonymize_sha1(const struct object_id *oid)
 338 {
 339         static struct hashmap sha1s;
 340         size_t len = GIT_SHA1_RAWSZ;
 341         return anonymize_mem(&sha1s, generate_fake_oid, oid, &len);
 342 }
 343
 344 static void show_filemodify(struct diff_queue_struct *q,
 345                             struct diff_options *options, void *data)
 346 {
 347         int i;
 348         struct string_list *changed = data;
 349
 350         /*
 351          * Handle files below a directory first, in case they are all deleted
 352          * and the directory changes to a file or symlink.
 353          */
 354         QSORT(q->queue, q->nr, depth_first);
 355
 356         for (i = 0; i < q->nr; i++) {
 357                 struct diff_filespec *ospec = q->queue[i]->one;
 358                 struct diff_filespec *spec = q->queue[i]->two;
 359
 360                 switch (q->queue[i]->status) {
 361                 case DIFF_STATUS_DELETED:
 362                         printf("D ");
 363                         print_path(spec->path);
 364                         string_list_insert(changed, spec->path);
 365                         putchar('\n');
 366                         break;
 367
 368                 case DIFF_STATUS_COPIED:
 369                 case DIFF_STATUS_RENAMED:
 370                         /*
 371                          * If a change in the file corresponding to ospec->path
 372                          * has been observed, we cannot trust its contents
 373                          * because the diff is calculated based on the prior
 374                          * contents, not the current contents.  So, declare a
 375                          * copy or rename only if there was no change observed.
 376                          */
 377                         if (!string_list_has_string(changed, ospec->path)) {
 378                                 printf("%c ", q->queue[i]->status);
 379                                 print_path(ospec->path);
 380                                 putchar(' ');
 381                                 print_path(spec->path);
 382                                 string_list_insert(changed, spec->path);
 383                                 putchar('\n');
 384
 385                                 if (!oidcmp(&ospec->oid, &spec->oid) &&
 386                                     ospec->mode == spec->mode)
 387                                         break;
 388                         }
 389                         /* fallthrough */
 390
 391                 case DIFF_STATUS_TYPE_CHANGED:
 392                 case DIFF_STATUS_MODIFIED:
 393                 case DIFF_STATUS_ADDED:
 394                         /*
 395                          * Links refer to objects in another repositories;
 396                          * output the SHA-1 verbatim.
 397                          */
 398                         if (no_data || S_ISGITLINK(spec->mode))
 399                                 printf("M %06o %s ", spec->mode,
 400                                        sha1_to_hex(anonymize ?
 401                                                    anonymize_sha1(&spec->oid) :
 402                                                    spec->oid.hash));
 403                         else {
 404                                 struct object *object = lookup_object(spec->oid.hash);
 405                                 printf("M %06o :%d ", spec->mode,
 406                                        get_object_mark(object));
 407                         }
 408                         print_path(spec->path);
 409                         string_list_insert(changed, spec->path);
 410                         putchar('\n');
 411                         break;
 412
 413                 default:
 414                         die("Unexpected comparison status '%c' for %s, %s",
 415                                 q->queue[i]->status,
 416                                 ospec->path ? ospec->path : "none",
 417                                 spec->path ? spec->path : "none");
 418                 }
 419         }
 420 }
 421
 422 static const char *find_encoding(const char *begin, const char *end)
 423 {
 424         const char *needle = "\nencoding ";
 425         char *bol, *eol;
 426
 427         bol = memmem(begin, end ? end - begin : strlen(begin),
 428                      needle, strlen(needle));
 429         if (!bol)
 430                 return git_commit_encoding;
 431         bol += strlen(needle);
 432         eol = strchrnul(bol, '\n');
 433         *eol = '\0';
 434         return bol;
 435 }
 436
 437 static void *anonymize_ref_component(const void *old, size_t *len)
 438 {
 439         static int counter;
 440         struct strbuf out = STRBUF_INIT;
 441         strbuf_addf(&out, "ref%d", counter++);
 442         return strbuf_detach(&out, len);
 443 }
 444
 445 static const char *anonymize_refname(const char *refname)
 446 {
 447         /*
 448          * If any of these prefixes is found, we will leave it intact
 449          * so that tags remain tags and so forth.
 450          */
 451         static const char *prefixes[] = {
 452                 "refs/heads/",
 453                 "refs/tags/",
 454                 "refs/remotes/",
 455                 "refs/"
 456         };
 457         static struct hashmap refs;
 458         static struct strbuf anon = STRBUF_INIT;
 459         int i;
 460
 461         /*
 462          * We also leave "master" as a special case, since it does not reveal
 463          * anything interesting.
 464          */
 465         if (!strcmp(refname, "refs/heads/master"))
 466                 return refname;
 467
 468         strbuf_reset(&anon);
 469         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
 470                 if (skip_prefix(refname, prefixes[i], &refname)) {
 471                         strbuf_addstr(&anon, prefixes[i]);
 472                         break;
 473                 }
 474         }
 475
 476         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
 477         return anon.buf;
 478 }
 479
 480 /*
 481  * We do not even bother to cache commit messages, as they are unlikely
 482  * to be repeated verbatim, and it is not that interesting when they are.
 483  */
 484 static char *anonymize_commit_message(const char *old)
 485 {
 486         static int counter;
 487         return xstrfmt("subject %d\n\nbody\n", counter++);
 488 }
 489
 490 static struct hashmap idents;
 491 static void *anonymize_ident(const void *old, size_t *len)
 492 {
 493         static int counter;
 494         struct strbuf out = STRBUF_INIT;
 495         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
 496         counter++;
 497         return strbuf_detach(&out, len);
 498 }
 499
 500 /*
 501  * Our strategy here is to anonymize the names and email addresses,
 502  * but keep timestamps intact, as they influence things like traversal
 503  * order (and by themselves should not be too revealing).
 504  */
 505 static void anonymize_ident_line(const char **beg, const char **end)
 506 {
 507         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
 508         static unsigned which_buffer;
 509
 510         struct strbuf *out;
 511         struct ident_split split;
 512         const char *end_of_header;
 513
 514         out = &buffers[which_buffer++];
 515         which_buffer %= ARRAY_SIZE(buffers);
 516         strbuf_reset(out);
 517
 518         /* skip "committer", "author", "tagger", etc */
 519         end_of_header = strchr(*beg, ' ');
 520         if (!end_of_header)
 521                 BUG("malformed line fed to anonymize_ident_line: %.*s",
 522                     (int)(*end - *beg), *beg);
 523         end_of_header++;
 524         strbuf_add(out, *beg, end_of_header - *beg);
 525
 526         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
 527             split.date_begin) {
 528                 const char *ident;
 529                 size_t len;
 530
 531                 len = split.mail_end - split.name_begin;
 532                 ident = anonymize_mem(&idents, anonymize_ident,
 533                                       split.name_begin, &len);
 534                 strbuf_add(out, ident, len);
 535                 strbuf_addch(out, ' ');
 536                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
 537         } else {
 538                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
 539         }
 540
 541         *beg = out->buf;
 542         *end = out->buf + out->len;
 543 }
 544
 545 static void handle_commit(struct commit *commit, struct rev_info *rev,
 546                           struct string_list *paths_of_changed_objects)
 547 {
 548         int saved_output_format = rev->diffopt.output_format;
 549         const char *commit_buffer;
 550         const char *author, *author_end, *committer, *committer_end;
 551         const char *encoding, *message;
 552         char *reencoded = NULL;
 553         struct commit_list *p;
 554         const char *refname;
 555         int i;
 556
 557         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
 558
 559         parse_commit_or_die(commit);
 560         commit_buffer = get_commit_buffer(commit, NULL);
 561         author = strstr(commit_buffer, "\nauthor ");
 562         if (!author)
 563                 die ("Could not find author in commit %s",
 564                      oid_to_hex(&commit->object.oid));
 565         author++;
 566         author_end = strchrnul(author, '\n');
 567         committer = strstr(author_end, "\ncommitter ");
 568         if (!committer)
 569                 die ("Could not find committer in commit %s",
 570                      oid_to_hex(&commit->object.oid));
 571         committer++;
 572         committer_end = strchrnul(committer, '\n');
 573         message = strstr(committer_end, "\n\n");
 574         encoding = find_encoding(committer_end, message);
 575         if (message)
 576                 message += 2;
 577
 578         if (commit->parents &&
 579             get_object_mark(&commit->parents->item->object) != 0 &&
 580             !full_tree) {
 581                 parse_commit_or_die(commit->parents->item);
 582                 diff_tree_oid(get_commit_tree_oid(commit->parents->item),
 583                               get_commit_tree_oid(commit), "", &rev->diffopt);
 584         }
 585         else
 586                 diff_root_tree_oid(get_commit_tree_oid(commit),
 587                                    "", &rev->diffopt);
 588
 589         /* Export the referenced blobs, and remember the marks. */
 590         for (i = 0; i < diff_queued_diff.nr; i++)
 591                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
 592                         export_blob(&diff_queued_diff.queue[i]->two->oid);
 593
 594         refname = *revision_sources_at(&revision_sources, commit);
 595         if (anonymize) {
 596                 refname = anonymize_refname(refname);
 597                 anonymize_ident_line(&committer, &committer_end);
 598                 anonymize_ident_line(&author, &author_end);
 599         }
 600
 601         mark_next_object(&commit->object);
 602         if (anonymize)
 603                 reencoded = anonymize_commit_message(message);
 604         else if (!is_encoding_utf8(encoding))
 605                 reencoded = reencode_string(message, "UTF-8", encoding);
 606         if (!commit->parents)
 607                 printf("reset %s\n", refname);
 608         printf("commit %s\nmark :%"PRIu32"\n%.*s\n%.*s\ndata %u\n%s",
 609                refname, last_idnum,
 610                (int)(author_end - author), author,
 611                (int)(committer_end - committer), committer,
 612                (unsigned)(reencoded
 613                           ? strlen(reencoded) : message
 614                           ? strlen(message) : 0),
 615                reencoded ? reencoded : message ? message : "");
 616         free(reencoded);
 617         unuse_commit_buffer(commit, commit_buffer);
 618
 619         for (i = 0, p = commit->parents; p; p = p->next) {
 620                 int mark = get_object_mark(&p->item->object);
 621                 if (!mark)
 622                         continue;
 623                 if (i == 0)
 624                         printf("from :%d\n", mark);
 625                 else
 626                         printf("merge :%d\n", mark);
 627                 i++;
 628         }
 629
 630         if (full_tree)
 631                 printf("deleteall\n");
 632         log_tree_diff_flush(rev);
 633         string_list_clear(paths_of_changed_objects, 0);
 634         rev->diffopt.output_format = saved_output_format;
 635
 636         printf("\n");
 637
 638         show_progress();
 639 }
 640
 641 static void *anonymize_tag(const void *old, size_t *len)
 642 {
 643         static int counter;
 644         struct strbuf out = STRBUF_INIT;
 645         strbuf_addf(&out, "tag message %d", counter++);
 646         return strbuf_detach(&out, len);
 647 }
 648
 649 static void handle_tail(struct object_array *commits, struct rev_info *revs,
 650                         struct string_list *paths_of_changed_objects)
 651 {
 652         struct commit *commit;
 653         while (commits->nr) {
 654                 commit = (struct commit *)object_array_pop(commits);
 655                 if (has_unshown_parent(commit)) {
 656                         /* Queue again, to be handled later */
 657                         add_object_array(&commit->object, NULL, commits);
 658                         return;
 659                 }
 660                 handle_commit(commit, revs, paths_of_changed_objects);
 661         }
 662 }
 663
 664 static void handle_tag(const char *name, struct tag *tag)
 665 {
 666         unsigned long size;
 667         enum object_type type;
 668         char *buf;
 669         const char *tagger, *tagger_end, *message;
 670         size_t message_size = 0;
 671         struct object *tagged;
 672         int tagged_mark;
 673         struct commit *p;
 674
 675         /* Trees have no identifier in fast-export output, thus we have no way
 676          * to output tags of trees, tags of tags of trees, etc.  Simply omit
 677          * such tags.
 678          */
 679         tagged = tag->tagged;
 680         while (tagged->type == OBJ_TAG) {
 681                 tagged = ((struct tag *)tagged)->tagged;
 682         }
 683         if (tagged->type == OBJ_TREE) {
 684                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
 685                         oid_to_hex(&tag->object.oid));
 686                 return;
 687         }
 688
 689         buf = read_object_file(&tag->object.oid, &type, &size);
 690         if (!buf)
 691                 die ("Could not read tag %s", oid_to_hex(&tag->object.oid));
 692         message = memmem(buf, size, "\n\n", 2);
 693         if (message) {
 694                 message += 2;
 695                 message_size = strlen(message);
 696         }
 697         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
 698         if (!tagger) {
 699                 if (fake_missing_tagger)
 700                         tagger = "tagger Unspecified Tagger "
 701                                 "<unspecified-tagger> 0 +0000";
 702                 else
 703                         tagger = "";
 704                 tagger_end = tagger + strlen(tagger);
 705         } else {
 706                 tagger++;
 707                 tagger_end = strchrnul(tagger, '\n');
 708                 if (anonymize)
 709                         anonymize_ident_line(&tagger, &tagger_end);
 710         }
 711
 712         if (anonymize) {
 713                 name = anonymize_refname(name);
 714                 if (message) {
 715                         static struct hashmap tags;
 716                         message = anonymize_mem(&tags, anonymize_tag,
 717                                                 message, &message_size);
 718                 }
 719         }
 720
 721         /* handle signed tags */
 722         if (message) {
 723                 const char *signature = strstr(message,
 724                                                "\n-----BEGIN PGP SIGNATURE-----\n");
 725                 if (signature)
 726                         switch(signed_tag_mode) {
 727                         case ABORT:
 728                                 die ("Encountered signed tag %s; use "
 729                                      "--signed-tags=<mode> to handle it.",
 730                                      oid_to_hex(&tag->object.oid));
 731                         case WARN:
 732                                 warning ("Exporting signed tag %s",
 733                                          oid_to_hex(&tag->object.oid));
 734                                 /* fallthru */
 735                         case VERBATIM:
 736                                 break;
 737                         case WARN_STRIP:
 738                                 warning ("Stripping signature from tag %s",
 739                                          oid_to_hex(&tag->object.oid));
 740                                 /* fallthru */
 741                         case STRIP:
 742                                 message_size = signature + 1 - message;
 743                                 break;
 744                         }
 745         }
 746
 747         /* handle tag->tagged having been filtered out due to paths specified */
 748         tagged = tag->tagged;
 749         tagged_mark = get_object_mark(tagged);
 750         if (!tagged_mark) {
 751                 switch(tag_of_filtered_mode) {
 752                 case ABORT:
 753                         die ("Tag %s tags unexported object; use "
 754                              "--tag-of-filtered-object=<mode> to handle it.",
 755                              oid_to_hex(&tag->object.oid));
 756                 case DROP:
 757                         /* Ignore this tag altogether */
 758                         free(buf);
 759                         return;
 760                 case REWRITE:
 761                         if (tagged->type != OBJ_COMMIT) {
 762                                 die ("Tag %s tags unexported %s!",
 763                                      oid_to_hex(&tag->object.oid),
 764                                      type_name(tagged->type));
 765                         }
 766                         p = (struct commit *)tagged;
 767                         for (;;) {
 768                                 if (p->parents && p->parents->next)
 769                                         break;
 770                                 if (p->object.flags & UNINTERESTING)
 771                                         break;
 772                                 if (!(p->object.flags & TREESAME))
 773                                         break;
 774                                 if (!p->parents)
 775                                         die ("Can't find replacement commit for tag %s\n",
 776                                              oid_to_hex(&tag->object.oid));
 777                                 p = p->parents->item;
 778                         }
 779                         tagged_mark = get_object_mark(&p->object);
 780                 }
 781         }
 782
 783         if (starts_with(name, "refs/tags/"))
 784                 name += 10;
 785         printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
 786                name, tagged_mark,
 787                (int)(tagger_end - tagger), tagger,
 788                tagger == tagger_end ? "" : "\n",
 789                (int)message_size, (int)message_size, message ? message : "");
 790         free(buf);
 791 }
 792
 793 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
 794 {
 795         switch (e->item->type) {
 796         case OBJ_COMMIT:
 797                 return (struct commit *)e->item;
 798         case OBJ_TAG: {
 799                 struct tag *tag = (struct tag *)e->item;
 800
 801                 /* handle nested tags */
 802                 while (tag && tag->object.type == OBJ_TAG) {
 803                         parse_object(&tag->object.oid);
 804                         string_list_append(&extra_refs, full_name)->util = tag;
 805                         tag = (struct tag *)tag->tagged;
 806                 }
 807                 if (!tag)
 808                         die("Tag %s points nowhere?", e->name);
 809                 return (struct commit *)tag;
 810                 break;
 811         }
 812         default:
 813                 return NULL;
 814         }
 815 }
 816
 817 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 818 {
 819         int i;
 820
 821         for (i = 0; i < info->nr; i++) {
 822                 struct rev_cmdline_entry *e = info->rev + i;
 823                 struct object_id oid;
 824                 struct commit *commit;
 825                 char *full_name;
 826
 827                 if (e->flags & UNINTERESTING)
 828                         continue;
 829
 830                 if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 831                         continue;
 832
 833                 if (refspecs.nr) {
 834                         char *private;
 835                         private = apply_refspecs(&refspecs, full_name);
 836                         if (private) {
 837                                 free(full_name);
 838                                 full_name = private;
 839                         }
 840                 }
 841
 842                 commit = get_commit(e, full_name);
 843                 if (!commit) {
 844                         warning("%s: Unexpected object of type %s, skipping.",
 845                                 e->name,
 846                                 type_name(e->item->type));
 847                         continue;
 848                 }
 849
 850                 switch(commit->object.type) {
 851                 case OBJ_COMMIT:
 852                         break;
 853                 case OBJ_BLOB:
 854                         export_blob(&commit->object.oid);
 855                         continue;
 856                 default: /* OBJ_TAG (nested tags) is already handled */
 857                         warning("Tag points to object of unexpected type %s, skipping.",
 858                                 type_name(commit->object.type));
 859                         continue;
 860                 }
 861
 862                 /*
 863                  * This ref will not be updated through a commit, lets make
 864                  * sure it gets properly updated eventually.
 865                  */
 866                 if (*revision_sources_at(&revision_sources, commit) ||
 867                     commit->object.flags & SHOWN)
 868                         string_list_append(&extra_refs, full_name)->util = commit;
 869                 if (!*revision_sources_at(&revision_sources, commit))
 870                         *revision_sources_at(&revision_sources, commit) = full_name;
 871         }
 872 }
 873
 874 static void handle_tags_and_duplicates(void)
 875 {
 876         struct commit *commit;
 877         int i;
 878
 879         for (i = extra_refs.nr - 1; i >= 0; i--) {
 880                 const char *name = extra_refs.items[i].string;
 881                 struct object *object = extra_refs.items[i].util;
 882                 switch (object->type) {
 883                 case OBJ_TAG:
 884                         handle_tag(name, (struct tag *)object);
 885                         break;
 886                 case OBJ_COMMIT:
 887                         if (anonymize)
 888                                 name = anonymize_refname(name);
 889                         /* create refs pointing to already seen commits */
 890                         commit = (struct commit *)object;
 891                         printf("reset %s\nfrom :%d\n\n", name,
 892                                get_object_mark(&commit->object));
 893                         show_progress();
 894                         break;
 895                 }
 896         }
 897 }
 898
 899 static void export_marks(char *file)
 900 {
 901         unsigned int i;
 902         uint32_t mark;
 903         struct decoration_entry *deco = idnums.entries;
 904         FILE *f;
 905         int e = 0;
 906
 907         f = fopen_for_writing(file);
 908         if (!f)
 909                 die_errno("Unable to open marks file %s for writing.", file);
 910
 911         for (i = 0; i < idnums.size; i++) {
 912                 if (deco->base && deco->base->type == 1) {
 913                         mark = ptr_to_mark(deco->decoration);
 914                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
 915                                 oid_to_hex(&deco->base->oid)) < 0) {
 916                             e = 1;
 917                             break;
 918                         }
 919                 }
 920                 deco++;
 921         }
 922
 923         e |= ferror(f);
 924         e |= fclose(f);
 925         if (e)
 926                 error("Unable to write marks file %s.", file);
 927 }
 928
 929 static void import_marks(char *input_file)
 930 {
 931         char line[512];
 932         FILE *f = xfopen(input_file, "r");
 933
 934         while (fgets(line, sizeof(line), f)) {
 935                 uint32_t mark;
 936                 char *line_end, *mark_end;
 937                 struct object_id oid;
 938                 struct object *object;
 939                 struct commit *commit;
 940                 enum object_type type;
 941
 942                 line_end = strchr(line, '\n');
 943                 if (line[0] != ':' || !line_end)
 944                         die("corrupt mark line: %s", line);
 945                 *line_end = '\0';
 946
 947                 mark = strtoumax(line + 1, &mark_end, 10);
 948                 if (!mark || mark_end == line + 1
 949                         || *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
 950                         die("corrupt mark line: %s", line);
 951
 952                 if (last_idnum < mark)
 953                         last_idnum = mark;
 954
 955                 type = oid_object_info(the_repository, &oid, NULL);
 956                 if (type < 0)
 957                         die("object not found: %s", oid_to_hex(&oid));
 958
 959                 if (type != OBJ_COMMIT)
 960                         /* only commits */
 961                         continue;
 962
 963                 commit = lookup_commit(&oid);
 964                 if (!commit)
 965                         die("not a commit? can't happen: %s", oid_to_hex(&oid));
 966
 967                 object = &commit->object;
 968
 969                 if (object->flags & SHOWN)
 970                         error("Object %s already has a mark", oid_to_hex(&oid));
 971
 972                 mark_object(object, mark);
 973
 974                 object->flags |= SHOWN;
 975         }
 976         fclose(f);
 977 }
 978
 979 static void handle_deletes(void)
 980 {
 981         int i;
 982         for (i = 0; i < refspecs.nr; i++) {
 983                 struct refspec_item *refspec = &refspecs.items[i];
 984                 if (*refspec->src)
 985                         continue;
 986
 987                 printf("reset %s\nfrom %s\n\n",
 988                                 refspec->dst, sha1_to_hex(null_sha1));
 989         }
 990 }
 991
 992 int cmd_fast_export(int argc, const char **argv, const char *prefix)
 993 {
 994         struct rev_info revs;
 995         struct object_array commits = OBJECT_ARRAY_INIT;
 996         struct commit *commit;
 997         char *export_filename = NULL, *import_filename = NULL;
 998         uint32_t lastimportid;
 999         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
1000         struct string_list paths_of_changed_objects = STRING_LIST_INIT_DUP;
1001         struct option options[] = {
1002                 OPT_INTEGER(0, "progress", &progress,
1003                             N_("show progress after <n> objects")),
1004                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
1005                              N_("select handling of signed tags"),
1006                              parse_opt_signed_tag_mode),
1007                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
1008                              N_("select handling of tags that tag filtered objects"),
1009                              parse_opt_tag_of_filtered_mode),
1010                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
1011                              N_("Dump marks to this file")),
1012                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
1013                              N_("Import marks from this file")),
1014                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
1015                          N_("Fake a tagger when tags lack one")),
1016                 OPT_BOOL(0, "full-tree", &full_tree,
1017                          N_("Output full tree for each commit")),
1018                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
1019                              N_("Use the done feature to terminate the stream")),
1020                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
1021                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
1022                              N_("Apply refspec to exported refs")),
1023                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1024                 OPT_END()
1025         };
1026
1027         if (argc == 1)
1028                 usage_with_options (fast_export_usage, options);
1029
1030         /* we handle encodings */
1031         git_config(git_default_config, NULL);
1032
1033         init_revisions(&revs, prefix);
1034         init_revision_sources(&revision_sources);
1035         revs.topo_order = 1;
1036         revs.sources = &revision_sources;
1037         revs.rewrite_parents = 1;
1038         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1039                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1040         argc = setup_revisions(argc, argv, &revs, NULL);
1041         if (argc > 1)
1042                 usage_with_options (fast_export_usage, options);
1043
1044         if (refspecs_list.nr) {
1045                 int i;
1046
1047                 for (i = 0; i < refspecs_list.nr; i++)
1048                         refspec_append(&refspecs, refspecs_list.items[i].string);
1049
1050                 string_list_clear(&refspecs_list, 1);
1051         }
1052
1053         if (use_done_feature)
1054                 printf("feature done\n");
1055
1056         if (import_filename)
1057                 import_marks(import_filename);
1058         lastimportid = last_idnum;
1059
1060         if (import_filename && revs.prune_data.nr)
1061                 full_tree = 1;
1062
1063         get_tags_and_duplicates(&revs.cmdline);
1064
1065         if (prepare_revision_walk(&revs))
1066                 die("revision walk setup failed");
1067         revs.diffopt.format_callback = show_filemodify;
1068         revs.diffopt.format_callback_data = &paths_of_changed_objects;
1069         revs.diffopt.flags.recursive = 1;
1070         while ((commit = get_revision(&revs))) {
1071                 if (has_unshown_parent(commit)) {
1072                         add_object_array(&commit->object, NULL, &commits);
1073                 }
1074                 else {
1075                         handle_commit(commit, &revs, &paths_of_changed_objects);
1076                         handle_tail(&commits, &revs, &paths_of_changed_objects);
1077                 }
1078         }
1079
1080         handle_tags_and_duplicates();
1081         handle_deletes();
1082
1083         if (export_filename && lastimportid != last_idnum)
1084                 export_marks(export_filename);
1085
1086         if (use_done_feature)
1087                 printf("done\n");
1088
1089         refspec_clear(&refspecs);
1090
1091         return 0;
1092 }