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 { ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = ABORT;
  35 static enum { ERROR, DROP, REWRITE } tag_of_filtered_mode = ERROR;
  36 static int fake_missing_tagger;
  37 static int use_done_feature;
  38 static int no_data;
  39 static int full_tree;
  40 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
  41 static struct refspec refspecs = REFSPEC_INIT_FETCH;
  42 static int anonymize;
  43 static struct revision_sources revision_sources;
  44
  45 static int parse_opt_signed_tag_mode(const struct option *opt,
  46                                      const char *arg, int unset)
  47 {
  48         if (unset || !strcmp(arg, "abort"))
  49                 signed_tag_mode = ABORT;
  50         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
  51                 signed_tag_mode = VERBATIM;
  52         else if (!strcmp(arg, "warn"))
  53                 signed_tag_mode = WARN;
  54         else if (!strcmp(arg, "warn-strip"))
  55                 signed_tag_mode = WARN_STRIP;
  56         else if (!strcmp(arg, "strip"))
  57                 signed_tag_mode = STRIP;
  58         else
  59                 return error("Unknown signed-tags mode: %s", arg);
  60         return 0;
  61 }
  62
  63 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
  64                                           const char *arg, int unset)
  65 {
  66         if (unset || !strcmp(arg, "abort"))
  67                 tag_of_filtered_mode = ERROR;
  68         else if (!strcmp(arg, "drop"))
  69                 tag_of_filtered_mode = DROP;
  70         else if (!strcmp(arg, "rewrite"))
  71                 tag_of_filtered_mode = REWRITE;
  72         else
  73                 return error("Unknown tag-of-filtered mode: %s", arg);
  74         return 0;
  75 }
  76
  77 static struct decoration idnums;
  78 static uint32_t last_idnum;
  79
  80 static int has_unshown_parent(struct commit *commit)
  81 {
  82         struct commit_list *parent;
  83
  84         for (parent = commit->parents; parent; parent = parent->next)
  85                 if (!(parent->item->object.flags & SHOWN) &&
  86                     !(parent->item->object.flags & UNINTERESTING))
  87                         return 1;
  88         return 0;
  89 }
  90
  91 struct anonymized_entry {
  92         struct hashmap_entry hash;
  93         const char *orig;
  94         size_t orig_len;
  95         const char *anon;
  96         size_t anon_len;
  97 };
  98
  99 static int anonymized_entry_cmp(const void *unused_cmp_data,
 100                                 const void *va, const void *vb,
 101                                 const void *unused_keydata)
 102 {
 103         const struct anonymized_entry *a = va, *b = vb;
 104         return a->orig_len != b->orig_len ||
 105                 memcmp(a->orig, b->orig, a->orig_len);
 106 }
 107
 108 /*
 109  * Basically keep a cache of X->Y so that we can repeatedly replace
 110  * the same anonymized string with another. The actual generation
 111  * is farmed out to the generate function.
 112  */
 113 static const void *anonymize_mem(struct hashmap *map,
 114                                  void *(*generate)(const void *, size_t *),
 115                                  const void *orig, size_t *len)
 116 {
 117         struct anonymized_entry key, *ret;
 118
 119         if (!map->cmpfn)
 120                 hashmap_init(map, anonymized_entry_cmp, NULL, 0);
 121
 122         hashmap_entry_init(&key, memhash(orig, *len));
 123         key.orig = orig;
 124         key.orig_len = *len;
 125         ret = hashmap_get(map, &key, NULL);
 126
 127         if (!ret) {
 128                 ret = xmalloc(sizeof(*ret));
 129                 hashmap_entry_init(&ret->hash, key.hash.hash);
 130                 ret->orig = xstrdup(orig);
 131                 ret->orig_len = *len;
 132                 ret->anon = generate(orig, len);
 133                 ret->anon_len = *len;
 134                 hashmap_put(map, ret);
 135         }
 136
 137         *len = ret->anon_len;
 138         return ret->anon;
 139 }
 140
 141 /*
 142  * We anonymize each component of a path individually,
 143  * so that paths a/b and a/c will share a common root.
 144  * The paths are cached via anonymize_mem so that repeated
 145  * lookups for "a" will yield the same value.
 146  */
 147 static void anonymize_path(struct strbuf *out, const char *path,
 148                            struct hashmap *map,
 149                            void *(*generate)(const void *, size_t *))
 150 {
 151         while (*path) {
 152                 const char *end_of_component = strchrnul(path, '/');
 153                 size_t len = end_of_component - path;
 154                 const char *c = anonymize_mem(map, generate, path, &len);
 155                 strbuf_add(out, c, len);
 156                 path = end_of_component;
 157                 if (*path)
 158                         strbuf_addch(out, *path++);
 159         }
 160 }
 161
 162 static inline void *mark_to_ptr(uint32_t mark)
 163 {
 164         return (void *)(uintptr_t)mark;
 165 }
 166
 167 static inline uint32_t ptr_to_mark(void * mark)
 168 {
 169         return (uint32_t)(uintptr_t)mark;
 170 }
 171
 172 static inline void mark_object(struct object *object, uint32_t mark)
 173 {
 174         add_decoration(&idnums, object, mark_to_ptr(mark));
 175 }
 176
 177 static inline void mark_next_object(struct object *object)
 178 {
 179         mark_object(object, ++last_idnum);
 180 }
 181
 182 static int get_object_mark(struct object *object)
 183 {
 184         void *decoration = lookup_decoration(&idnums, object);
 185         if (!decoration)
 186                 return 0;
 187         return ptr_to_mark(decoration);
 188 }
 189
 190 static void show_progress(void)
 191 {
 192         static int counter = 0;
 193         if (!progress)
 194                 return;
 195         if ((++counter % progress) == 0)
 196                 printf("progress %d objects\n", counter);
 197 }
 198
 199 /*
 200  * Ideally we would want some transformation of the blob data here
 201  * that is unreversible, but would still be the same size and have
 202  * the same data relationship to other blobs (so that we get the same
 203  * delta and packing behavior as the original). But the first and last
 204  * requirements there are probably mutually exclusive, so let's take
 205  * the easy way out for now, and just generate arbitrary content.
 206  *
 207  * There's no need to cache this result with anonymize_mem, since
 208  * we already handle blob content caching with marks.
 209  */
 210 static char *anonymize_blob(unsigned long *size)
 211 {
 212         static int counter;
 213         struct strbuf out = STRBUF_INIT;
 214         strbuf_addf(&out, "anonymous blob %d", counter++);
 215         *size = out.len;
 216         return strbuf_detach(&out, NULL);
 217 }
 218
 219 static void export_blob(const struct object_id *oid)
 220 {
 221         unsigned long size;
 222         enum object_type type;
 223         char *buf;
 224         struct object *object;
 225         int eaten;
 226
 227         if (no_data)
 228                 return;
 229
 230         if (is_null_oid(oid))
 231                 return;
 232
 233         object = lookup_object(oid->hash);
 234         if (object && object->flags & SHOWN)
 235                 return;
 236
 237         if (anonymize) {
 238                 buf = anonymize_blob(&size);
 239                 object = (struct object *)lookup_blob(oid);
 240                 eaten = 0;
 241         } else {
 242                 buf = read_object_file(oid, &type, &size);
 243                 if (!buf)
 244                         die ("Could not read blob %s", oid_to_hex(oid));
 245                 if (check_object_signature(oid, buf, size, type_name(type)) < 0)
 246                         die("sha1 mismatch in blob %s", oid_to_hex(oid));
 247                 object = parse_object_buffer(oid, type, size, buf, &eaten);
 248         }
 249
 250         if (!object)
 251                 die("Could not read blob %s", oid_to_hex(oid));
 252
 253         mark_next_object(object);
 254
 255         printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
 256         if (size && fwrite(buf, size, 1, stdout) != 1)
 257                 die_errno ("Could not write blob '%s'", oid_to_hex(oid));
 258         printf("\n");
 259
 260         show_progress();
 261
 262         object->flags |= SHOWN;
 263         if (!eaten)
 264                 free(buf);
 265 }
 266
 267 static int depth_first(const void *a_, const void *b_)
 268 {
 269         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
 270         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
 271         const char *name_a, *name_b;
 272         int len_a, len_b, len;
 273         int cmp;
 274
 275         name_a = a->one ? a->one->path : a->two->path;
 276         name_b = b->one ? b->one->path : b->two->path;
 277
 278         len_a = strlen(name_a);
 279         len_b = strlen(name_b);
 280         len = (len_a < len_b) ? len_a : len_b;
 281
 282         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
 283         cmp = memcmp(name_a, name_b, len);
 284         if (cmp)
 285                 return cmp;
 286         cmp = len_b - len_a;
 287         if (cmp)
 288                 return cmp;
 289         /*
 290          * Move 'R'ename entries last so that all references of the file
 291          * appear in the output before it is renamed (e.g., when a file
 292          * was copied and renamed in the same commit).
 293          */
 294         return (a->status == 'R') - (b->status == 'R');
 295 }
 296
 297 static void print_path_1(const char *path)
 298 {
 299         int need_quote = quote_c_style(path, NULL, NULL, 0);
 300         if (need_quote)
 301                 quote_c_style(path, NULL, stdout, 0);
 302         else if (strchr(path, ' '))
 303                 printf("\"%s\"", path);
 304         else
 305                 printf("%s", path);
 306 }
 307
 308 static void *anonymize_path_component(const void *path, size_t *len)
 309 {
 310         static int counter;
 311         struct strbuf out = STRBUF_INIT;
 312         strbuf_addf(&out, "path%d", counter++);
 313         return strbuf_detach(&out, len);
 314 }
 315
 316 static void print_path(const char *path)
 317 {
 318         if (!anonymize)
 319                 print_path_1(path);
 320         else {
 321                 static struct hashmap paths;
 322                 static struct strbuf anon = STRBUF_INIT;
 323
 324                 anonymize_path(&anon, path, &paths, anonymize_path_component);
 325                 print_path_1(anon.buf);
 326                 strbuf_reset(&anon);
 327         }
 328 }
 329
 330 static void *generate_fake_oid(const void *old, size_t *len)
 331 {
 332         static uint32_t counter = 1; /* avoid null sha1 */
 333         unsigned char *out = xcalloc(GIT_SHA1_RAWSZ, 1);
 334         put_be32(out + GIT_SHA1_RAWSZ - 4, counter++);
 335         return out;
 336 }
 337
 338 static const unsigned char *anonymize_sha1(const struct object_id *oid)
 339 {
 340         static struct hashmap sha1s;
 341         size_t len = GIT_SHA1_RAWSZ;
 342         return anonymize_mem(&sha1s, generate_fake_oid, oid, &len);
 343 }
 344
 345 static void show_filemodify(struct diff_queue_struct *q,
 346                             struct diff_options *options, void *data)
 347 {
 348         int i;
 349         struct string_list *changed = data;
 350
 351         /*
 352          * Handle files below a directory first, in case they are all deleted
 353          * and the directory changes to a file or symlink.
 354          */
 355         QSORT(q->queue, q->nr, depth_first);
 356
 357         for (i = 0; i < q->nr; i++) {
 358                 struct diff_filespec *ospec = q->queue[i]->one;
 359                 struct diff_filespec *spec = q->queue[i]->two;
 360
 361                 switch (q->queue[i]->status) {
 362                 case DIFF_STATUS_DELETED:
 363                         printf("D ");
 364                         print_path(spec->path);
 365                         string_list_insert(changed, spec->path);
 366                         putchar('\n');
 367                         break;
 368
 369                 case DIFF_STATUS_COPIED:
 370                 case DIFF_STATUS_RENAMED:
 371                         /*
 372                          * If a change in the file corresponding to ospec->path
 373                          * has been observed, we cannot trust its contents
 374                          * because the diff is calculated based on the prior
 375                          * contents, not the current contents.  So, declare a
 376                          * copy or rename only if there was no change observed.
 377                          */
 378                         if (!string_list_has_string(changed, ospec->path)) {
 379                                 printf("%c ", q->queue[i]->status);
 380                                 print_path(ospec->path);
 381                                 putchar(' ');
 382                                 print_path(spec->path);
 383                                 string_list_insert(changed, spec->path);
 384                                 putchar('\n');
 385
 386                                 if (!oidcmp(&ospec->oid, &spec->oid) &&
 387                                     ospec->mode == spec->mode)
 388                                         break;
 389                         }
 390                         /* fallthrough */
 391
 392                 case DIFF_STATUS_TYPE_CHANGED:
 393                 case DIFF_STATUS_MODIFIED:
 394                 case DIFF_STATUS_ADDED:
 395                         /*
 396                          * Links refer to objects in another repositories;
 397                          * output the SHA-1 verbatim.
 398                          */
 399                         if (no_data || S_ISGITLINK(spec->mode))
 400                                 printf("M %06o %s ", spec->mode,
 401                                        sha1_to_hex(anonymize ?
 402                                                    anonymize_sha1(&spec->oid) :
 403                                                    spec->oid.hash));
 404                         else {
 405                                 struct object *object = lookup_object(spec->oid.hash);
 406                                 printf("M %06o :%d ", spec->mode,
 407                                        get_object_mark(object));
 408                         }
 409                         print_path(spec->path);
 410                         string_list_insert(changed, spec->path);
 411                         putchar('\n');
 412                         break;
 413
 414                 default:
 415                         die("Unexpected comparison status '%c' for %s, %s",
 416                                 q->queue[i]->status,
 417                                 ospec->path ? ospec->path : "none",
 418                                 spec->path ? spec->path : "none");
 419                 }
 420         }
 421 }
 422
 423 static const char *find_encoding(const char *begin, const char *end)
 424 {
 425         const char *needle = "\nencoding ";
 426         char *bol, *eol;
 427
 428         bol = memmem(begin, end ? end - begin : strlen(begin),
 429                      needle, strlen(needle));
 430         if (!bol)
 431                 return git_commit_encoding;
 432         bol += strlen(needle);
 433         eol = strchrnul(bol, '\n');
 434         *eol = '\0';
 435         return bol;
 436 }
 437
 438 static void *anonymize_ref_component(const void *old, size_t *len)
 439 {
 440         static int counter;
 441         struct strbuf out = STRBUF_INIT;
 442         strbuf_addf(&out, "ref%d", counter++);
 443         return strbuf_detach(&out, len);
 444 }
 445
 446 static const char *anonymize_refname(const char *refname)
 447 {
 448         /*
 449          * If any of these prefixes is found, we will leave it intact
 450          * so that tags remain tags and so forth.
 451          */
 452         static const char *prefixes[] = {
 453                 "refs/heads/",
 454                 "refs/tags/",
 455                 "refs/remotes/",
 456                 "refs/"
 457         };
 458         static struct hashmap refs;
 459         static struct strbuf anon = STRBUF_INIT;
 460         int i;
 461
 462         /*
 463          * We also leave "master" as a special case, since it does not reveal
 464          * anything interesting.
 465          */
 466         if (!strcmp(refname, "refs/heads/master"))
 467                 return refname;
 468
 469         strbuf_reset(&anon);
 470         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
 471                 if (skip_prefix(refname, prefixes[i], &refname)) {
 472                         strbuf_addstr(&anon, prefixes[i]);
 473                         break;
 474                 }
 475         }
 476
 477         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
 478         return anon.buf;
 479 }
 480
 481 /*
 482  * We do not even bother to cache commit messages, as they are unlikely
 483  * to be repeated verbatim, and it is not that interesting when they are.
 484  */
 485 static char *anonymize_commit_message(const char *old)
 486 {
 487         static int counter;
 488         return xstrfmt("subject %d\n\nbody\n", counter++);
 489 }
 490
 491 static struct hashmap idents;
 492 static void *anonymize_ident(const void *old, size_t *len)
 493 {
 494         static int counter;
 495         struct strbuf out = STRBUF_INIT;
 496         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
 497         counter++;
 498         return strbuf_detach(&out, len);
 499 }
 500
 501 /*
 502  * Our strategy here is to anonymize the names and email addresses,
 503  * but keep timestamps intact, as they influence things like traversal
 504  * order (and by themselves should not be too revealing).
 505  */
 506 static void anonymize_ident_line(const char **beg, const char **end)
 507 {
 508         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
 509         static unsigned which_buffer;
 510
 511         struct strbuf *out;
 512         struct ident_split split;
 513         const char *end_of_header;
 514
 515         out = &buffers[which_buffer++];
 516         which_buffer %= ARRAY_SIZE(buffers);
 517         strbuf_reset(out);
 518
 519         /* skip "committer", "author", "tagger", etc */
 520         end_of_header = strchr(*beg, ' ');
 521         if (!end_of_header)
 522                 BUG("malformed line fed to anonymize_ident_line: %.*s",
 523                     (int)(*end - *beg), *beg);
 524         end_of_header++;
 525         strbuf_add(out, *beg, end_of_header - *beg);
 526
 527         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
 528             split.date_begin) {
 529                 const char *ident;
 530                 size_t len;
 531
 532                 len = split.mail_end - split.name_begin;
 533                 ident = anonymize_mem(&idents, anonymize_ident,
 534                                       split.name_begin, &len);
 535                 strbuf_add(out, ident, len);
 536                 strbuf_addch(out, ' ');
 537                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
 538         } else {
 539                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
 540         }
 541
 542         *beg = out->buf;
 543         *end = out->buf + out->len;
 544 }
 545
 546 static void handle_commit(struct commit *commit, struct rev_info *rev,
 547                           struct string_list *paths_of_changed_objects)
 548 {
 549         int saved_output_format = rev->diffopt.output_format;
 550         const char *commit_buffer;
 551         const char *author, *author_end, *committer, *committer_end;
 552         const char *encoding, *message;
 553         char *reencoded = NULL;
 554         struct commit_list *p;
 555         const char *refname;
 556         int i;
 557
 558         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
 559
 560         parse_commit_or_die(commit);
 561         commit_buffer = get_commit_buffer(commit, NULL);
 562         author = strstr(commit_buffer, "\nauthor ");
 563         if (!author)
 564                 die ("Could not find author in commit %s",
 565                      oid_to_hex(&commit->object.oid));
 566         author++;
 567         author_end = strchrnul(author, '\n');
 568         committer = strstr(author_end, "\ncommitter ");
 569         if (!committer)
 570                 die ("Could not find committer in commit %s",
 571                      oid_to_hex(&commit->object.oid));
 572         committer++;
 573         committer_end = strchrnul(committer, '\n');
 574         message = strstr(committer_end, "\n\n");
 575         encoding = find_encoding(committer_end, message);
 576         if (message)
 577                 message += 2;
 578
 579         if (commit->parents &&
 580             get_object_mark(&commit->parents->item->object) != 0 &&
 581             !full_tree) {
 582                 parse_commit_or_die(commit->parents->item);
 583                 diff_tree_oid(get_commit_tree_oid(commit->parents->item),
 584                               get_commit_tree_oid(commit), "", &rev->diffopt);
 585         }
 586         else
 587                 diff_root_tree_oid(get_commit_tree_oid(commit),
 588                                    "", &rev->diffopt);
 589
 590         /* Export the referenced blobs, and remember the marks. */
 591         for (i = 0; i < diff_queued_diff.nr; i++)
 592                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
 593                         export_blob(&diff_queued_diff.queue[i]->two->oid);
 594
 595         refname = *revision_sources_at(&revision_sources, commit);
 596         if (anonymize) {
 597                 refname = anonymize_refname(refname);
 598                 anonymize_ident_line(&committer, &committer_end);
 599                 anonymize_ident_line(&author, &author_end);
 600         }
 601
 602         mark_next_object(&commit->object);
 603         if (anonymize)
 604                 reencoded = anonymize_commit_message(message);
 605         else if (!is_encoding_utf8(encoding))
 606                 reencoded = reencode_string(message, "UTF-8", encoding);
 607         if (!commit->parents)
 608                 printf("reset %s\n", refname);
 609         printf("commit %s\nmark :%"PRIu32"\n%.*s\n%.*s\ndata %u\n%s",
 610                refname, last_idnum,
 611                (int)(author_end - author), author,
 612                (int)(committer_end - committer), committer,
 613                (unsigned)(reencoded
 614                           ? strlen(reencoded) : message
 615                           ? strlen(message) : 0),
 616                reencoded ? reencoded : message ? message : "");
 617         free(reencoded);
 618         unuse_commit_buffer(commit, commit_buffer);
 619
 620         for (i = 0, p = commit->parents; p; p = p->next) {
 621                 int mark = get_object_mark(&p->item->object);
 622                 if (!mark)
 623                         continue;
 624                 if (i == 0)
 625                         printf("from :%d\n", mark);
 626                 else
 627                         printf("merge :%d\n", mark);
 628                 i++;
 629         }
 630
 631         if (full_tree)
 632                 printf("deleteall\n");
 633         log_tree_diff_flush(rev);
 634         string_list_clear(paths_of_changed_objects, 0);
 635         rev->diffopt.output_format = saved_output_format;
 636
 637         printf("\n");
 638
 639         show_progress();
 640 }
 641
 642 static void *anonymize_tag(const void *old, size_t *len)
 643 {
 644         static int counter;
 645         struct strbuf out = STRBUF_INIT;
 646         strbuf_addf(&out, "tag message %d", counter++);
 647         return strbuf_detach(&out, len);
 648 }
 649
 650 static void handle_tail(struct object_array *commits, struct rev_info *revs,
 651                         struct string_list *paths_of_changed_objects)
 652 {
 653         struct commit *commit;
 654         while (commits->nr) {
 655                 commit = (struct commit *)object_array_pop(commits);
 656                 if (has_unshown_parent(commit)) {
 657                         /* Queue again, to be handled later */
 658                         add_object_array(&commit->object, NULL, commits);
 659                         return;
 660                 }
 661                 handle_commit(commit, revs, paths_of_changed_objects);
 662         }
 663 }
 664
 665 static void handle_tag(const char *name, struct tag *tag)
 666 {
 667         unsigned long size;
 668         enum object_type type;
 669         char *buf;
 670         const char *tagger, *tagger_end, *message;
 671         size_t message_size = 0;
 672         struct object *tagged;
 673         int tagged_mark;
 674         struct commit *p;
 675
 676         /* Trees have no identifier in fast-export output, thus we have no way
 677          * to output tags of trees, tags of tags of trees, etc.  Simply omit
 678          * such tags.
 679          */
 680         tagged = tag->tagged;
 681         while (tagged->type == OBJ_TAG) {
 682                 tagged = ((struct tag *)tagged)->tagged;
 683         }
 684         if (tagged->type == OBJ_TREE) {
 685                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
 686                         oid_to_hex(&tag->object.oid));
 687                 return;
 688         }
 689
 690         buf = read_object_file(&tag->object.oid, &type, &size);
 691         if (!buf)
 692                 die ("Could not read tag %s", oid_to_hex(&tag->object.oid));
 693         message = memmem(buf, size, "\n\n", 2);
 694         if (message) {
 695                 message += 2;
 696                 message_size = strlen(message);
 697         }
 698         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
 699         if (!tagger) {
 700                 if (fake_missing_tagger)
 701                         tagger = "tagger Unspecified Tagger "
 702                                 "<unspecified-tagger> 0 +0000";
 703                 else
 704                         tagger = "";
 705                 tagger_end = tagger + strlen(tagger);
 706         } else {
 707                 tagger++;
 708                 tagger_end = strchrnul(tagger, '\n');
 709                 if (anonymize)
 710                         anonymize_ident_line(&tagger, &tagger_end);
 711         }
 712
 713         if (anonymize) {
 714                 name = anonymize_refname(name);
 715                 if (message) {
 716                         static struct hashmap tags;
 717                         message = anonymize_mem(&tags, anonymize_tag,
 718                                                 message, &message_size);
 719                 }
 720         }
 721
 722         /* handle signed tags */
 723         if (message) {
 724                 const char *signature = strstr(message,
 725                                                "\n-----BEGIN PGP SIGNATURE-----\n");
 726                 if (signature)
 727                         switch(signed_tag_mode) {
 728                         case ABORT:
 729                                 die ("Encountered signed tag %s; use "
 730                                      "--signed-tags=<mode> to handle it.",
 731                                      oid_to_hex(&tag->object.oid));
 732                         case WARN:
 733                                 warning ("Exporting signed tag %s",
 734                                          oid_to_hex(&tag->object.oid));
 735                                 /* fallthru */
 736                         case VERBATIM:
 737                                 break;
 738                         case WARN_STRIP:
 739                                 warning ("Stripping signature from tag %s",
 740                                          oid_to_hex(&tag->object.oid));
 741                                 /* fallthru */
 742                         case STRIP:
 743                                 message_size = signature + 1 - message;
 744                                 break;
 745                         }
 746         }
 747
 748         /* handle tag->tagged having been filtered out due to paths specified */
 749         tagged = tag->tagged;
 750         tagged_mark = get_object_mark(tagged);
 751         if (!tagged_mark) {
 752                 switch(tag_of_filtered_mode) {
 753                 case ABORT:
 754                         die ("Tag %s tags unexported object; use "
 755                              "--tag-of-filtered-object=<mode> to handle it.",
 756                              oid_to_hex(&tag->object.oid));
 757                 case DROP:
 758                         /* Ignore this tag altogether */
 759                         free(buf);
 760                         return;
 761                 case REWRITE:
 762                         if (tagged->type != OBJ_COMMIT) {
 763                                 die ("Tag %s tags unexported %s!",
 764                                      oid_to_hex(&tag->object.oid),
 765                                      type_name(tagged->type));
 766                         }
 767                         p = (struct commit *)tagged;
 768                         for (;;) {
 769                                 if (p->parents && p->parents->next)
 770                                         break;
 771                                 if (p->object.flags & UNINTERESTING)
 772                                         break;
 773                                 if (!(p->object.flags & TREESAME))
 774                                         break;
 775                                 if (!p->parents)
 776                                         die ("Can't find replacement commit for tag %s\n",
 777                                              oid_to_hex(&tag->object.oid));
 778                                 p = p->parents->item;
 779                         }
 780                         tagged_mark = get_object_mark(&p->object);
 781                 }
 782         }
 783
 784         if (starts_with(name, "refs/tags/"))
 785                 name += 10;
 786         printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
 787                name, tagged_mark,
 788                (int)(tagger_end - tagger), tagger,
 789                tagger == tagger_end ? "" : "\n",
 790                (int)message_size, (int)message_size, message ? message : "");
 791         free(buf);
 792 }
 793
 794 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
 795 {
 796         switch (e->item->type) {
 797         case OBJ_COMMIT:
 798                 return (struct commit *)e->item;
 799         case OBJ_TAG: {
 800                 struct tag *tag = (struct tag *)e->item;
 801
 802                 /* handle nested tags */
 803                 while (tag && tag->object.type == OBJ_TAG) {
 804                         parse_object(&tag->object.oid);
 805                         string_list_append(&extra_refs, full_name)->util = tag;
 806                         tag = (struct tag *)tag->tagged;
 807                 }
 808                 if (!tag)
 809                         die("Tag %s points nowhere?", e->name);
 810                 return (struct commit *)tag;
 811                 break;
 812         }
 813         default:
 814                 return NULL;
 815         }
 816 }
 817
 818 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 819 {
 820         int i;
 821
 822         for (i = 0; i < info->nr; i++) {
 823                 struct rev_cmdline_entry *e = info->rev + i;
 824                 struct object_id oid;
 825                 struct commit *commit;
 826                 char *full_name;
 827
 828                 if (e->flags & UNINTERESTING)
 829                         continue;
 830
 831                 if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 832                         continue;
 833
 834                 if (refspecs.nr) {
 835                         char *private;
 836                         private = apply_refspecs(&refspecs, full_name);
 837                         if (private) {
 838                                 free(full_name);
 839                                 full_name = private;
 840                         }
 841                 }
 842
 843                 commit = get_commit(e, full_name);
 844                 if (!commit) {
 845                         warning("%s: Unexpected object of type %s, skipping.",
 846                                 e->name,
 847                                 type_name(e->item->type));
 848                         continue;
 849                 }
 850
 851                 switch(commit->object.type) {
 852                 case OBJ_COMMIT:
 853                         break;
 854                 case OBJ_BLOB:
 855                         export_blob(&commit->object.oid);
 856                         continue;
 857                 default: /* OBJ_TAG (nested tags) is already handled */
 858                         warning("Tag points to object of unexpected type %s, skipping.",
 859                                 type_name(commit->object.type));
 860                         continue;
 861                 }
 862
 863                 /*
 864                  * This ref will not be updated through a commit, lets make
 865                  * sure it gets properly updated eventually.
 866                  */
 867                 if (*revision_sources_at(&revision_sources, commit) ||
 868                     commit->object.flags & SHOWN)
 869                         string_list_append(&extra_refs, full_name)->util = commit;
 870                 if (!*revision_sources_at(&revision_sources, commit))
 871                         *revision_sources_at(&revision_sources, commit) = full_name;
 872         }
 873 }
 874
 875 static void handle_tags_and_duplicates(void)
 876 {
 877         struct commit *commit;
 878         int i;
 879
 880         for (i = extra_refs.nr - 1; i >= 0; i--) {
 881                 const char *name = extra_refs.items[i].string;
 882                 struct object *object = extra_refs.items[i].util;
 883                 switch (object->type) {
 884                 case OBJ_TAG:
 885                         handle_tag(name, (struct tag *)object);
 886                         break;
 887                 case OBJ_COMMIT:
 888                         if (anonymize)
 889                                 name = anonymize_refname(name);
 890                         /* create refs pointing to already seen commits */
 891                         commit = (struct commit *)object;
 892                         printf("reset %s\nfrom :%d\n\n", name,
 893                                get_object_mark(&commit->object));
 894                         show_progress();
 895                         break;
 896                 }
 897         }
 898 }
 899
 900 static void export_marks(char *file)
 901 {
 902         unsigned int i;
 903         uint32_t mark;
 904         struct decoration_entry *deco = idnums.entries;
 905         FILE *f;
 906         int e = 0;
 907
 908         f = fopen_for_writing(file);
 909         if (!f)
 910                 die_errno("Unable to open marks file %s for writing.", file);
 911
 912         for (i = 0; i < idnums.size; i++) {
 913                 if (deco->base && deco->base->type == 1) {
 914                         mark = ptr_to_mark(deco->decoration);
 915                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
 916                                 oid_to_hex(&deco->base->oid)) < 0) {
 917                             e = 1;
 918                             break;
 919                         }
 920                 }
 921                 deco++;
 922         }
 923
 924         e |= ferror(f);
 925         e |= fclose(f);
 926         if (e)
 927                 error("Unable to write marks file %s.", file);
 928 }
 929
 930 static void import_marks(char *input_file)
 931 {
 932         char line[512];
 933         FILE *f = xfopen(input_file, "r");
 934
 935         while (fgets(line, sizeof(line), f)) {
 936                 uint32_t mark;
 937                 char *line_end, *mark_end;
 938                 struct object_id oid;
 939                 struct object *object;
 940                 struct commit *commit;
 941                 enum object_type type;
 942
 943                 line_end = strchr(line, '\n');
 944                 if (line[0] != ':' || !line_end)
 945                         die("corrupt mark line: %s", line);
 946                 *line_end = '\0';
 947
 948                 mark = strtoumax(line + 1, &mark_end, 10);
 949                 if (!mark || mark_end == line + 1
 950                         || *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
 951                         die("corrupt mark line: %s", line);
 952
 953                 if (last_idnum < mark)
 954                         last_idnum = mark;
 955
 956                 type = oid_object_info(the_repository, &oid, NULL);
 957                 if (type < 0)
 958                         die("object not found: %s", oid_to_hex(&oid));
 959
 960                 if (type != OBJ_COMMIT)
 961                         /* only commits */
 962                         continue;
 963
 964                 commit = lookup_commit(&oid);
 965                 if (!commit)
 966                         die("not a commit? can't happen: %s", oid_to_hex(&oid));
 967
 968                 object = &commit->object;
 969
 970                 if (object->flags & SHOWN)
 971                         error("Object %s already has a mark", oid_to_hex(&oid));
 972
 973                 mark_object(object, mark);
 974
 975                 object->flags |= SHOWN;
 976         }
 977         fclose(f);
 978 }
 979
 980 static void handle_deletes(void)
 981 {
 982         int i;
 983         for (i = 0; i < refspecs.nr; i++) {
 984                 struct refspec_item *refspec = &refspecs.items[i];
 985                 if (*refspec->src)
 986                         continue;
 987
 988                 printf("reset %s\nfrom %s\n\n",
 989                                 refspec->dst, sha1_to_hex(null_sha1));
 990         }
 991 }
 992
 993 int cmd_fast_export(int argc, const char **argv, const char *prefix)
 994 {
 995         struct rev_info revs;
 996         struct object_array commits = OBJECT_ARRAY_INIT;
 997         struct commit *commit;
 998         char *export_filename = NULL, *import_filename = NULL;
 999         uint32_t lastimportid;
1000         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
1001         struct string_list paths_of_changed_objects = STRING_LIST_INIT_DUP;
1002         struct option options[] = {
1003                 OPT_INTEGER(0, "progress", &progress,
1004                             N_("show progress after <n> objects")),
1005                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
1006                              N_("select handling of signed tags"),
1007                              parse_opt_signed_tag_mode),
1008                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
1009                              N_("select handling of tags that tag filtered objects"),
1010                              parse_opt_tag_of_filtered_mode),
1011                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
1012                              N_("Dump marks to this file")),
1013                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
1014                              N_("Import marks from this file")),
1015                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
1016                          N_("Fake a tagger when tags lack one")),
1017                 OPT_BOOL(0, "full-tree", &full_tree,
1018                          N_("Output full tree for each commit")),
1019                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
1020                              N_("Use the done feature to terminate the stream")),
1021                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
1022                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
1023                              N_("Apply refspec to exported refs")),
1024                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1025                 OPT_END()
1026         };
1027
1028         if (argc == 1)
1029                 usage_with_options (fast_export_usage, options);
1030
1031         /* we handle encodings */
1032         git_config(git_default_config, NULL);
1033
1034         init_revisions(&revs, prefix);
1035         init_revision_sources(&revision_sources);
1036         revs.topo_order = 1;
1037         revs.sources = &revision_sources;
1038         revs.rewrite_parents = 1;
1039         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1040                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1041         argc = setup_revisions(argc, argv, &revs, NULL);
1042         if (argc > 1)
1043                 usage_with_options (fast_export_usage, options);
1044
1045         if (refspecs_list.nr) {
1046                 int i;
1047
1048                 for (i = 0; i < refspecs_list.nr; i++)
1049                         refspec_append(&refspecs, refspecs_list.items[i].string);
1050
1051                 string_list_clear(&refspecs_list, 1);
1052         }
1053
1054         if (use_done_feature)
1055                 printf("feature done\n");
1056
1057         if (import_filename)
1058                 import_marks(import_filename);
1059         lastimportid = last_idnum;
1060
1061         if (import_filename && revs.prune_data.nr)
1062                 full_tree = 1;
1063
1064         get_tags_and_duplicates(&revs.cmdline);
1065
1066         if (prepare_revision_walk(&revs))
1067                 die("revision walk setup failed");
1068         revs.diffopt.format_callback = show_filemodify;
1069         revs.diffopt.format_callback_data = &paths_of_changed_objects;
1070         revs.diffopt.flags.recursive = 1;
1071         while ((commit = get_revision(&revs))) {
1072                 if (has_unshown_parent(commit)) {
1073                         add_object_array(&commit->object, NULL, &commits);
1074                 }
1075                 else {
1076                         handle_commit(commit, &revs, &paths_of_changed_objects);
1077                         handle_tail(&commits, &revs, &paths_of_changed_objects);
1078                 }
1079         }
1080
1081         handle_tags_and_duplicates();
1082         handle_deletes();
1083
1084         if (export_filename && lastimportid != last_idnum)
1085                 export_marks(export_filename);
1086
1087         if (use_done_feature)
1088                 printf("done\n");
1089
1090         refspec_clear(&refspecs);
1091
1092         return 0;
1093 }