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 int fake_missing_tagger;
  37 static int use_done_feature;
  38 static int no_data;
  39 static int full_tree;
  40 static int reference_excluded_commits;
  41 static int show_original_ids;
  42 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
  43 static struct string_list tag_refs = STRING_LIST_INIT_NODUP;
  44 static struct refspec refspecs = REFSPEC_INIT_FETCH;
  45 static int anonymize;
  46 static struct revision_sources revision_sources;
  47
  48 static int parse_opt_signed_tag_mode(const struct option *opt,
  49                                      const char *arg, int unset)
  50 {
  51         if (unset || !strcmp(arg, "abort"))
  52                 signed_tag_mode = SIGNED_TAG_ABORT;
  53         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
  54                 signed_tag_mode = VERBATIM;
  55         else if (!strcmp(arg, "warn"))
  56                 signed_tag_mode = WARN;
  57         else if (!strcmp(arg, "warn-strip"))
  58                 signed_tag_mode = WARN_STRIP;
  59         else if (!strcmp(arg, "strip"))
  60                 signed_tag_mode = STRIP;
  61         else
  62                 return error("Unknown signed-tags mode: %s", arg);
  63         return 0;
  64 }
  65
  66 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
  67                                           const char *arg, int unset)
  68 {
  69         if (unset || !strcmp(arg, "abort"))
  70                 tag_of_filtered_mode = TAG_FILTERING_ABORT;
  71         else if (!strcmp(arg, "drop"))
  72                 tag_of_filtered_mode = DROP;
  73         else if (!strcmp(arg, "rewrite"))
  74                 tag_of_filtered_mode = REWRITE;
  75         else
  76                 return error("Unknown tag-of-filtered mode: %s", arg);
  77         return 0;
  78 }
  79
  80 static struct decoration idnums;
  81 static uint32_t last_idnum;
  82
  83 static int has_unshown_parent(struct commit *commit)
  84 {
  85         struct commit_list *parent;
  86
  87         for (parent = commit->parents; parent; parent = parent->next)
  88                 if (!(parent->item->object.flags & SHOWN) &&
  89                     !(parent->item->object.flags & UNINTERESTING))
  90                         return 1;
  91         return 0;
  92 }
  93
  94 struct anonymized_entry {
  95         struct hashmap_entry hash;
  96         const char *orig;
  97         size_t orig_len;
  98         const char *anon;
  99         size_t anon_len;
 100 };
 101
 102 static int anonymized_entry_cmp(const void *unused_cmp_data,
 103                                 const void *va, const void *vb,
 104                                 const void *unused_keydata)
 105 {
 106         const struct anonymized_entry *a = va, *b = vb;
 107         return a->orig_len != b->orig_len ||
 108                 memcmp(a->orig, b->orig, a->orig_len);
 109 }
 110
 111 /*
 112  * Basically keep a cache of X->Y so that we can repeatedly replace
 113  * the same anonymized string with another. The actual generation
 114  * is farmed out to the generate function.
 115  */
 116 static const void *anonymize_mem(struct hashmap *map,
 117                                  void *(*generate)(const void *, size_t *),
 118                                  const void *orig, size_t *len)
 119 {
 120         struct anonymized_entry key, *ret;
 121
 122         if (!map->cmpfn)
 123                 hashmap_init(map, anonymized_entry_cmp, NULL, 0);
 124
 125         hashmap_entry_init(&key, memhash(orig, *len));
 126         key.orig = orig;
 127         key.orig_len = *len;
 128         ret = hashmap_get(map, &key, NULL);
 129
 130         if (!ret) {
 131                 ret = xmalloc(sizeof(*ret));
 132                 hashmap_entry_init(&ret->hash, key.hash.hash);
 133                 ret->orig = xstrdup(orig);
 134                 ret->orig_len = *len;
 135                 ret->anon = generate(orig, len);
 136                 ret->anon_len = *len;
 137                 hashmap_put(map, ret);
 138         }
 139
 140         *len = ret->anon_len;
 141         return ret->anon;
 142 }
 143
 144 /*
 145  * We anonymize each component of a path individually,
 146  * so that paths a/b and a/c will share a common root.
 147  * The paths are cached via anonymize_mem so that repeated
 148  * lookups for "a" will yield the same value.
 149  */
 150 static void anonymize_path(struct strbuf *out, const char *path,
 151                            struct hashmap *map,
 152                            void *(*generate)(const void *, size_t *))
 153 {
 154         while (*path) {
 155                 const char *end_of_component = strchrnul(path, '/');
 156                 size_t len = end_of_component - path;
 157                 const char *c = anonymize_mem(map, generate, path, &len);
 158                 strbuf_add(out, c, len);
 159                 path = end_of_component;
 160                 if (*path)
 161                         strbuf_addch(out, *path++);
 162         }
 163 }
 164
 165 static inline void *mark_to_ptr(uint32_t mark)
 166 {
 167         return (void *)(uintptr_t)mark;
 168 }
 169
 170 static inline uint32_t ptr_to_mark(void * mark)
 171 {
 172         return (uint32_t)(uintptr_t)mark;
 173 }
 174
 175 static inline void mark_object(struct object *object, uint32_t mark)
 176 {
 177         add_decoration(&idnums, object, mark_to_ptr(mark));
 178 }
 179
 180 static inline void mark_next_object(struct object *object)
 181 {
 182         mark_object(object, ++last_idnum);
 183 }
 184
 185 static int get_object_mark(struct object *object)
 186 {
 187         void *decoration = lookup_decoration(&idnums, object);
 188         if (!decoration)
 189                 return 0;
 190         return ptr_to_mark(decoration);
 191 }
 192
 193 static struct commit *rewrite_commit(struct commit *p)
 194 {
 195         for (;;) {
 196                 if (p->parents && p->parents->next)
 197                         break;
 198                 if (p->object.flags & UNINTERESTING)
 199                         break;
 200                 if (!(p->object.flags & TREESAME))
 201                         break;
 202                 if (!p->parents)
 203                         return NULL;
 204                 p = p->parents->item;
 205         }
 206         return p;
 207 }
 208
 209 static void show_progress(void)
 210 {
 211         static int counter = 0;
 212         if (!progress)
 213                 return;
 214         if ((++counter % progress) == 0)
 215                 printf("progress %d objects\n", counter);
 216 }
 217
 218 /*
 219  * Ideally we would want some transformation of the blob data here
 220  * that is unreversible, but would still be the same size and have
 221  * the same data relationship to other blobs (so that we get the same
 222  * delta and packing behavior as the original). But the first and last
 223  * requirements there are probably mutually exclusive, so let's take
 224  * the easy way out for now, and just generate arbitrary content.
 225  *
 226  * There's no need to cache this result with anonymize_mem, since
 227  * we already handle blob content caching with marks.
 228  */
 229 static char *anonymize_blob(unsigned long *size)
 230 {
 231         static int counter;
 232         struct strbuf out = STRBUF_INIT;
 233         strbuf_addf(&out, "anonymous blob %d", counter++);
 234         *size = out.len;
 235         return strbuf_detach(&out, NULL);
 236 }
 237
 238 static void export_blob(const struct object_id *oid)
 239 {
 240         unsigned long size;
 241         enum object_type type;
 242         char *buf;
 243         struct object *object;
 244         int eaten;
 245
 246         if (no_data)
 247                 return;
 248
 249         if (is_null_oid(oid))
 250                 return;
 251
 252         object = lookup_object(the_repository, oid->hash);
 253         if (object && object->flags & SHOWN)
 254                 return;
 255
 256         if (anonymize) {
 257                 buf = anonymize_blob(&size);
 258                 object = (struct object *)lookup_blob(the_repository, oid);
 259                 eaten = 0;
 260         } else {
 261                 buf = read_object_file(oid, &type, &size);
 262                 if (!buf)
 263                         die("could not read blob %s", oid_to_hex(oid));
 264                 if (check_object_signature(oid, buf, size, type_name(type)) < 0)
 265                         die("oid mismatch in blob %s", oid_to_hex(oid));
 266                 object = parse_object_buffer(the_repository, oid, type,
 267                                              size, buf, &eaten);
 268         }
 269
 270         if (!object)
 271                 die("Could not read blob %s", oid_to_hex(oid));
 272
 273         mark_next_object(object);
 274
 275         printf("blob\nmark :%"PRIu32"\n", last_idnum);
 276         if (show_original_ids)
 277                 printf("original-oid %s\n", oid_to_hex(oid));
 278         printf("data %"PRIuMAX"\n", (uintmax_t)size);
 279         if (size && fwrite(buf, size, 1, stdout) != 1)
 280                 die_errno("could not write blob '%s'", oid_to_hex(oid));
 281         printf("\n");
 282
 283         show_progress();
 284
 285         object->flags |= SHOWN;
 286         if (!eaten)
 287                 free(buf);
 288 }
 289
 290 static int depth_first(const void *a_, const void *b_)
 291 {
 292         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
 293         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
 294         const char *name_a, *name_b;
 295         int len_a, len_b, len;
 296         int cmp;
 297
 298         name_a = a->one ? a->one->path : a->two->path;
 299         name_b = b->one ? b->one->path : b->two->path;
 300
 301         len_a = strlen(name_a);
 302         len_b = strlen(name_b);
 303         len = (len_a < len_b) ? len_a : len_b;
 304
 305         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
 306         cmp = memcmp(name_a, name_b, len);
 307         if (cmp)
 308                 return cmp;
 309         cmp = len_b - len_a;
 310         if (cmp)
 311                 return cmp;
 312         /*
 313          * Move 'R'ename entries last so that all references of the file
 314          * appear in the output before it is renamed (e.g., when a file
 315          * was copied and renamed in the same commit).
 316          */
 317         return (a->status == 'R') - (b->status == 'R');
 318 }
 319
 320 static void print_path_1(const char *path)
 321 {
 322         int need_quote = quote_c_style(path, NULL, NULL, 0);
 323         if (need_quote)
 324                 quote_c_style(path, NULL, stdout, 0);
 325         else if (strchr(path, ' '))
 326                 printf("\"%s\"", path);
 327         else
 328                 printf("%s", path);
 329 }
 330
 331 static void *anonymize_path_component(const void *path, size_t *len)
 332 {
 333         static int counter;
 334         struct strbuf out = STRBUF_INIT;
 335         strbuf_addf(&out, "path%d", counter++);
 336         return strbuf_detach(&out, len);
 337 }
 338
 339 static void print_path(const char *path)
 340 {
 341         if (!anonymize)
 342                 print_path_1(path);
 343         else {
 344                 static struct hashmap paths;
 345                 static struct strbuf anon = STRBUF_INIT;
 346
 347                 anonymize_path(&anon, path, &paths, anonymize_path_component);
 348                 print_path_1(anon.buf);
 349                 strbuf_reset(&anon);
 350         }
 351 }
 352
 353 static void *generate_fake_oid(const void *old, size_t *len)
 354 {
 355         static uint32_t counter = 1; /* avoid null oid */
 356         const unsigned hashsz = the_hash_algo->rawsz;
 357         unsigned char *out = xcalloc(hashsz, 1);
 358         put_be32(out + hashsz - 4, counter++);
 359         return out;
 360 }
 361
 362 static const struct object_id *anonymize_oid(const struct object_id *oid)
 363 {
 364         static struct hashmap objs;
 365         size_t len = the_hash_algo->rawsz;
 366         return anonymize_mem(&objs, generate_fake_oid, oid, &len);
 367 }
 368
 369 static void show_filemodify(struct diff_queue_struct *q,
 370                             struct diff_options *options, void *data)
 371 {
 372         int i;
 373         struct string_list *changed = data;
 374
 375         /*
 376          * Handle files below a directory first, in case they are all deleted
 377          * and the directory changes to a file or symlink.
 378          */
 379         QSORT(q->queue, q->nr, depth_first);
 380
 381         for (i = 0; i < q->nr; i++) {
 382                 struct diff_filespec *ospec = q->queue[i]->one;
 383                 struct diff_filespec *spec = q->queue[i]->two;
 384
 385                 switch (q->queue[i]->status) {
 386                 case DIFF_STATUS_DELETED:
 387                         printf("D ");
 388                         print_path(spec->path);
 389                         string_list_insert(changed, spec->path);
 390                         putchar('\n');
 391                         break;
 392
 393                 case DIFF_STATUS_COPIED:
 394                 case DIFF_STATUS_RENAMED:
 395                         /*
 396                          * If a change in the file corresponding to ospec->path
 397                          * has been observed, we cannot trust its contents
 398                          * because the diff is calculated based on the prior
 399                          * contents, not the current contents.  So, declare a
 400                          * copy or rename only if there was no change observed.
 401                          */
 402                         if (!string_list_has_string(changed, ospec->path)) {
 403                                 printf("%c ", q->queue[i]->status);
 404                                 print_path(ospec->path);
 405                                 putchar(' ');
 406                                 print_path(spec->path);
 407                                 string_list_insert(changed, spec->path);
 408                                 putchar('\n');
 409
 410                                 if (oideq(&ospec->oid, &spec->oid) &&
 411                                     ospec->mode == spec->mode)
 412                                         break;
 413                         }
 414                         /* fallthrough */
 415
 416                 case DIFF_STATUS_TYPE_CHANGED:
 417                 case DIFF_STATUS_MODIFIED:
 418                 case DIFF_STATUS_ADDED:
 419                         /*
 420                          * Links refer to objects in another repositories;
 421                          * output the SHA-1 verbatim.
 422                          */
 423                         if (no_data || S_ISGITLINK(spec->mode))
 424                                 printf("M %06o %s ", spec->mode,
 425                                        oid_to_hex(anonymize ?
 426                                                   anonymize_oid(&spec->oid) :
 427                                                   &spec->oid));
 428                         else {
 429                                 struct object *object = lookup_object(the_repository,
 430                                                                       spec->oid.hash);
 431                                 printf("M %06o :%d ", spec->mode,
 432                                        get_object_mark(object));
 433                         }
 434                         print_path(spec->path);
 435                         string_list_insert(changed, spec->path);
 436                         putchar('\n');
 437                         break;
 438
 439                 default:
 440                         die("Unexpected comparison status '%c' for %s, %s",
 441                                 q->queue[i]->status,
 442                                 ospec->path ? ospec->path : "none",
 443                                 spec->path ? spec->path : "none");
 444                 }
 445         }
 446 }
 447
 448 static const char *find_encoding(const char *begin, const char *end)
 449 {
 450         const char *needle = "\nencoding ";
 451         char *bol, *eol;
 452
 453         bol = memmem(begin, end ? end - begin : strlen(begin),
 454                      needle, strlen(needle));
 455         if (!bol)
 456                 return git_commit_encoding;
 457         bol += strlen(needle);
 458         eol = strchrnul(bol, '\n');
 459         *eol = '\0';
 460         return bol;
 461 }
 462
 463 static void *anonymize_ref_component(const void *old, size_t *len)
 464 {
 465         static int counter;
 466         struct strbuf out = STRBUF_INIT;
 467         strbuf_addf(&out, "ref%d", counter++);
 468         return strbuf_detach(&out, len);
 469 }
 470
 471 static const char *anonymize_refname(const char *refname)
 472 {
 473         /*
 474          * If any of these prefixes is found, we will leave it intact
 475          * so that tags remain tags and so forth.
 476          */
 477         static const char *prefixes[] = {
 478                 "refs/heads/",
 479                 "refs/tags/",
 480                 "refs/remotes/",
 481                 "refs/"
 482         };
 483         static struct hashmap refs;
 484         static struct strbuf anon = STRBUF_INIT;
 485         int i;
 486
 487         /*
 488          * We also leave "master" as a special case, since it does not reveal
 489          * anything interesting.
 490          */
 491         if (!strcmp(refname, "refs/heads/master"))
 492                 return refname;
 493
 494         strbuf_reset(&anon);
 495         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
 496                 if (skip_prefix(refname, prefixes[i], &refname)) {
 497                         strbuf_addstr(&anon, prefixes[i]);
 498                         break;
 499                 }
 500         }
 501
 502         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
 503         return anon.buf;
 504 }
 505
 506 /*
 507  * We do not even bother to cache commit messages, as they are unlikely
 508  * to be repeated verbatim, and it is not that interesting when they are.
 509  */
 510 static char *anonymize_commit_message(const char *old)
 511 {
 512         static int counter;
 513         return xstrfmt("subject %d\n\nbody\n", counter++);
 514 }
 515
 516 static struct hashmap idents;
 517 static void *anonymize_ident(const void *old, size_t *len)
 518 {
 519         static int counter;
 520         struct strbuf out = STRBUF_INIT;
 521         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
 522         counter++;
 523         return strbuf_detach(&out, len);
 524 }
 525
 526 /*
 527  * Our strategy here is to anonymize the names and email addresses,
 528  * but keep timestamps intact, as they influence things like traversal
 529  * order (and by themselves should not be too revealing).
 530  */
 531 static void anonymize_ident_line(const char **beg, const char **end)
 532 {
 533         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
 534         static unsigned which_buffer;
 535
 536         struct strbuf *out;
 537         struct ident_split split;
 538         const char *end_of_header;
 539
 540         out = &buffers[which_buffer++];
 541         which_buffer %= ARRAY_SIZE(buffers);
 542         strbuf_reset(out);
 543
 544         /* skip "committer", "author", "tagger", etc */
 545         end_of_header = strchr(*beg, ' ');
 546         if (!end_of_header)
 547                 BUG("malformed line fed to anonymize_ident_line: %.*s",
 548                     (int)(*end - *beg), *beg);
 549         end_of_header++;
 550         strbuf_add(out, *beg, end_of_header - *beg);
 551
 552         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
 553             split.date_begin) {
 554                 const char *ident;
 555                 size_t len;
 556
 557                 len = split.mail_end - split.name_begin;
 558                 ident = anonymize_mem(&idents, anonymize_ident,
 559                                       split.name_begin, &len);
 560                 strbuf_add(out, ident, len);
 561                 strbuf_addch(out, ' ');
 562                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
 563         } else {
 564                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
 565         }
 566
 567         *beg = out->buf;
 568         *end = out->buf + out->len;
 569 }
 570
 571 static void handle_commit(struct commit *commit, struct rev_info *rev,
 572                           struct string_list *paths_of_changed_objects)
 573 {
 574         int saved_output_format = rev->diffopt.output_format;
 575         const char *commit_buffer;
 576         const char *author, *author_end, *committer, *committer_end;
 577         const char *encoding, *message;
 578         char *reencoded = NULL;
 579         struct commit_list *p;
 580         const char *refname;
 581         int i;
 582
 583         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
 584
 585         parse_commit_or_die(commit);
 586         commit_buffer = get_commit_buffer(commit, NULL);
 587         author = strstr(commit_buffer, "\nauthor ");
 588         if (!author)
 589                 die("could not find author in commit %s",
 590                     oid_to_hex(&commit->object.oid));
 591         author++;
 592         author_end = strchrnul(author, '\n');
 593         committer = strstr(author_end, "\ncommitter ");
 594         if (!committer)
 595                 die("could not find committer in commit %s",
 596                     oid_to_hex(&commit->object.oid));
 597         committer++;
 598         committer_end = strchrnul(committer, '\n');
 599         message = strstr(committer_end, "\n\n");
 600         encoding = find_encoding(committer_end, message);
 601         if (message)
 602                 message += 2;
 603
 604         if (commit->parents &&
 605             (get_object_mark(&commit->parents->item->object) != 0 ||
 606              reference_excluded_commits) &&
 607             !full_tree) {
 608                 parse_commit_or_die(commit->parents->item);
 609                 diff_tree_oid(get_commit_tree_oid(commit->parents->item),
 610                               get_commit_tree_oid(commit), "", &rev->diffopt);
 611         }
 612         else
 613                 diff_root_tree_oid(get_commit_tree_oid(commit),
 614                                    "", &rev->diffopt);
 615
 616         /* Export the referenced blobs, and remember the marks. */
 617         for (i = 0; i < diff_queued_diff.nr; i++)
 618                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
 619                         export_blob(&diff_queued_diff.queue[i]->two->oid);
 620
 621         refname = *revision_sources_at(&revision_sources, commit);
 622         /*
 623          * FIXME: string_list_remove() below for each ref is overall
 624          * O(N^2).  Compared to a history walk and diffing trees, this is
 625          * just lost in the noise in practice.  However, theoretically a
 626          * repo may have enough refs for this to become slow.
 627          */
 628         string_list_remove(&extra_refs, refname, 0);
 629         if (anonymize) {
 630                 refname = anonymize_refname(refname);
 631                 anonymize_ident_line(&committer, &committer_end);
 632                 anonymize_ident_line(&author, &author_end);
 633         }
 634
 635         mark_next_object(&commit->object);
 636         if (anonymize)
 637                 reencoded = anonymize_commit_message(message);
 638         else if (!is_encoding_utf8(encoding))
 639                 reencoded = reencode_string(message, "UTF-8", encoding);
 640         if (!commit->parents)
 641                 printf("reset %s\n", refname);
 642         printf("commit %s\nmark :%"PRIu32"\n", refname, last_idnum);
 643         if (show_original_ids)
 644                 printf("original-oid %s\n", oid_to_hex(&commit->object.oid));
 645         printf("%.*s\n%.*s\ndata %u\n%s",
 646                (int)(author_end - author), author,
 647                (int)(committer_end - committer), committer,
 648                (unsigned)(reencoded
 649                           ? strlen(reencoded) : message
 650                           ? strlen(message) : 0),
 651                reencoded ? reencoded : message ? message : "");
 652         free(reencoded);
 653         unuse_commit_buffer(commit, commit_buffer);
 654
 655         for (i = 0, p = commit->parents; p; p = p->next) {
 656                 struct object *obj = &p->item->object;
 657                 int mark = get_object_mark(obj);
 658
 659                 if (!mark && !reference_excluded_commits)
 660                         continue;
 661                 if (i == 0)
 662                         printf("from ");
 663                 else
 664                         printf("merge ");
 665                 if (mark)
 666                         printf(":%d\n", mark);
 667                 else
 668                         printf("%s\n", oid_to_hex(anonymize ?
 669                                                   anonymize_oid(&obj->oid) :
 670                                                   &obj->oid));
 671                 i++;
 672         }
 673
 674         if (full_tree)
 675                 printf("deleteall\n");
 676         log_tree_diff_flush(rev);
 677         string_list_clear(paths_of_changed_objects, 0);
 678         rev->diffopt.output_format = saved_output_format;
 679
 680         printf("\n");
 681
 682         show_progress();
 683 }
 684
 685 static void *anonymize_tag(const void *old, size_t *len)
 686 {
 687         static int counter;
 688         struct strbuf out = STRBUF_INIT;
 689         strbuf_addf(&out, "tag message %d", counter++);
 690         return strbuf_detach(&out, len);
 691 }
 692
 693 static void handle_tail(struct object_array *commits, struct rev_info *revs,
 694                         struct string_list *paths_of_changed_objects)
 695 {
 696         struct commit *commit;
 697         while (commits->nr) {
 698                 commit = (struct commit *)object_array_pop(commits);
 699                 if (has_unshown_parent(commit)) {
 700                         /* Queue again, to be handled later */
 701                         add_object_array(&commit->object, NULL, commits);
 702                         return;
 703                 }
 704                 handle_commit(commit, revs, paths_of_changed_objects);
 705         }
 706 }
 707
 708 static void handle_tag(const char *name, struct tag *tag)
 709 {
 710         unsigned long size;
 711         enum object_type type;
 712         char *buf;
 713         const char *tagger, *tagger_end, *message;
 714         size_t message_size = 0;
 715         struct object *tagged;
 716         int tagged_mark;
 717         struct commit *p;
 718
 719         /* Trees have no identifier in fast-export output, thus we have no way
 720          * to output tags of trees, tags of tags of trees, etc.  Simply omit
 721          * such tags.
 722          */
 723         tagged = tag->tagged;
 724         while (tagged->type == OBJ_TAG) {
 725                 tagged = ((struct tag *)tagged)->tagged;
 726         }
 727         if (tagged->type == OBJ_TREE) {
 728                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
 729                         oid_to_hex(&tag->object.oid));
 730                 return;
 731         }
 732
 733         buf = read_object_file(&tag->object.oid, &type, &size);
 734         if (!buf)
 735                 die("could not read tag %s", oid_to_hex(&tag->object.oid));
 736         message = memmem(buf, size, "\n\n", 2);
 737         if (message) {
 738                 message += 2;
 739                 message_size = strlen(message);
 740         }
 741         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
 742         if (!tagger) {
 743                 if (fake_missing_tagger)
 744                         tagger = "tagger Unspecified Tagger "
 745                                 "<unspecified-tagger> 0 +0000";
 746                 else
 747                         tagger = "";
 748                 tagger_end = tagger + strlen(tagger);
 749         } else {
 750                 tagger++;
 751                 tagger_end = strchrnul(tagger, '\n');
 752                 if (anonymize)
 753                         anonymize_ident_line(&tagger, &tagger_end);
 754         }
 755
 756         if (anonymize) {
 757                 name = anonymize_refname(name);
 758                 if (message) {
 759                         static struct hashmap tags;
 760                         message = anonymize_mem(&tags, anonymize_tag,
 761                                                 message, &message_size);
 762                 }
 763         }
 764
 765         /* handle signed tags */
 766         if (message) {
 767                 const char *signature = strstr(message,
 768                                                "\n-----BEGIN PGP SIGNATURE-----\n");
 769                 if (signature)
 770                         switch(signed_tag_mode) {
 771                         case SIGNED_TAG_ABORT:
 772                                 die("encountered signed tag %s; use "
 773                                     "--signed-tags=<mode> to handle it",
 774                                     oid_to_hex(&tag->object.oid));
 775                         case WARN:
 776                                 warning("exporting signed tag %s",
 777                                         oid_to_hex(&tag->object.oid));
 778                                 /* fallthru */
 779                         case VERBATIM:
 780                                 break;
 781                         case WARN_STRIP:
 782                                 warning("stripping signature from tag %s",
 783                                         oid_to_hex(&tag->object.oid));
 784                                 /* fallthru */
 785                         case STRIP:
 786                                 message_size = signature + 1 - message;
 787                                 break;
 788                         }
 789         }
 790
 791         /* handle tag->tagged having been filtered out due to paths specified */
 792         tagged = tag->tagged;
 793         tagged_mark = get_object_mark(tagged);
 794         if (!tagged_mark) {
 795                 switch(tag_of_filtered_mode) {
 796                 case TAG_FILTERING_ABORT:
 797                         die("tag %s tags unexported object; use "
 798                             "--tag-of-filtered-object=<mode> to handle it",
 799                             oid_to_hex(&tag->object.oid));
 800                 case DROP:
 801                         /* Ignore this tag altogether */
 802                         free(buf);
 803                         return;
 804                 case REWRITE:
 805                         if (tagged->type != OBJ_COMMIT) {
 806                                 die("tag %s tags unexported %s!",
 807                                     oid_to_hex(&tag->object.oid),
 808                                     type_name(tagged->type));
 809                         }
 810                         p = rewrite_commit((struct commit *)tagged);
 811                         if (!p) {
 812                                 printf("reset %s\nfrom %s\n\n",
 813                                        name, oid_to_hex(&null_oid));
 814                                 free(buf);
 815                                 return;
 816                         }
 817                         tagged_mark = get_object_mark(&p->object);
 818                 }
 819         }
 820
 821         if (starts_with(name, "refs/tags/"))
 822                 name += 10;
 823         printf("tag %s\nfrom :%d\n", name, tagged_mark);
 824         if (show_original_ids)
 825                 printf("original-oid %s\n", oid_to_hex(&tag->object.oid));
 826         printf("%.*s%sdata %d\n%.*s\n",
 827                (int)(tagger_end - tagger), tagger,
 828                tagger == tagger_end ? "" : "\n",
 829                (int)message_size, (int)message_size, message ? message : "");
 830         free(buf);
 831 }
 832
 833 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
 834 {
 835         switch (e->item->type) {
 836         case OBJ_COMMIT:
 837                 return (struct commit *)e->item;
 838         case OBJ_TAG: {
 839                 struct tag *tag = (struct tag *)e->item;
 840
 841                 /* handle nested tags */
 842                 while (tag && tag->object.type == OBJ_TAG) {
 843                         parse_object(the_repository, &tag->object.oid);
 844                         string_list_append(&tag_refs, full_name)->util = tag;
 845                         tag = (struct tag *)tag->tagged;
 846                 }
 847                 if (!tag)
 848                         die("Tag %s points nowhere?", e->name);
 849                 return (struct commit *)tag;
 850                 break;
 851         }
 852         default:
 853                 return NULL;
 854         }
 855 }
 856
 857 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
 858 {
 859         int i;
 860
 861         for (i = 0; i < info->nr; i++) {
 862                 struct rev_cmdline_entry *e = info->rev + i;
 863                 struct object_id oid;
 864                 struct commit *commit;
 865                 char *full_name;
 866
 867                 if (e->flags & UNINTERESTING)
 868                         continue;
 869
 870                 if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
 871                         continue;
 872
 873                 if (refspecs.nr) {
 874                         char *private;
 875                         private = apply_refspecs(&refspecs, full_name);
 876                         if (private) {
 877                                 free(full_name);
 878                                 full_name = private;
 879                         }
 880                 }
 881
 882                 commit = get_commit(e, full_name);
 883                 if (!commit) {
 884                         warning("%s: Unexpected object of type %s, skipping.",
 885                                 e->name,
 886                                 type_name(e->item->type));
 887                         continue;
 888                 }
 889
 890                 switch(commit->object.type) {
 891                 case OBJ_COMMIT:
 892                         break;
 893                 case OBJ_BLOB:
 894                         export_blob(&commit->object.oid);
 895                         continue;
 896                 default: /* OBJ_TAG (nested tags) is already handled */
 897                         warning("Tag points to object of unexpected type %s, skipping.",
 898                                 type_name(commit->object.type));
 899                         continue;
 900                 }
 901
 902                 /*
 903                  * Make sure this ref gets properly updated eventually, whether
 904                  * through a commit or manually at the end.
 905                  */
 906                 if (e->item->type != OBJ_TAG)
 907                         string_list_append(&extra_refs, full_name)->util = commit;
 908
 909                 if (!*revision_sources_at(&revision_sources, commit))
 910                         *revision_sources_at(&revision_sources, commit) = full_name;
 911         }
 912
 913         string_list_sort(&extra_refs);
 914         string_list_remove_duplicates(&extra_refs, 0);
 915 }
 916
 917 static void handle_tags_and_duplicates(struct string_list *extras)
 918 {
 919         struct commit *commit;
 920         int i;
 921
 922         for (i = extras->nr - 1; i >= 0; i--) {
 923                 const char *name = extras->items[i].string;
 924                 struct object *object = extras->items[i].util;
 925                 int mark;
 926
 927                 switch (object->type) {
 928                 case OBJ_TAG:
 929                         handle_tag(name, (struct tag *)object);
 930                         break;
 931                 case OBJ_COMMIT:
 932                         if (anonymize)
 933                                 name = anonymize_refname(name);
 934                         /* create refs pointing to already seen commits */
 935                         commit = rewrite_commit((struct commit *)object);
 936                         if (!commit) {
 937                                 /*
 938                                  * Neither this object nor any of its
 939                                  * ancestors touch any relevant paths, so
 940                                  * it has been filtered to nothing.  Delete
 941                                  * it.
 942                                  */
 943                                 printf("reset %s\nfrom %s\n\n",
 944                                        name, oid_to_hex(&null_oid));
 945                                 continue;
 946                         }
 947
 948                         mark = get_object_mark(&commit->object);
 949                         if (!mark) {
 950                                 /*
 951                                  * Getting here means we have a commit which
 952                                  * was excluded by a negative refspec (e.g.
 953                                  * fast-export ^master master).  If we are
 954                                  * referencing excluded commits, set the ref
 955                                  * to the exact commit.  Otherwise, the user
 956                                  * wants the branch exported but every commit
 957                                  * in its history to be deleted, which basically
 958                                  * just means deletion of the ref.
 959                                  */
 960                                 if (!reference_excluded_commits) {
 961                                         /* delete the ref */
 962                                         printf("reset %s\nfrom %s\n\n",
 963                                                name, oid_to_hex(&null_oid));
 964                                         continue;
 965                                 }
 966                                 /* set ref to commit using oid, not mark */
 967                                 printf("reset %s\nfrom %s\n\n", name,
 968                                        oid_to_hex(&commit->object.oid));
 969                                 continue;
 970                         }
 971
 972                         printf("reset %s\nfrom :%d\n\n", name, mark
 973                                );
 974                         show_progress();
 975                         break;
 976                 }
 977         }
 978 }
 979
 980 static void export_marks(char *file)
 981 {
 982         unsigned int i;
 983         uint32_t mark;
 984         struct decoration_entry *deco = idnums.entries;
 985         FILE *f;
 986         int e = 0;
 987
 988         f = fopen_for_writing(file);
 989         if (!f)
 990                 die_errno("Unable to open marks file %s for writing.", file);
 991
 992         for (i = 0; i < idnums.size; i++) {
 993                 if (deco->base && deco->base->type == 1) {
 994                         mark = ptr_to_mark(deco->decoration);
 995                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
 996                                 oid_to_hex(&deco->base->oid)) < 0) {
 997                             e = 1;
 998                             break;
 999                         }
1000                 }
1001                 deco++;
1002         }
1003
1004         e |= ferror(f);
1005         e |= fclose(f);
1006         if (e)
1007                 error("Unable to write marks file %s.", file);
1008 }
1009
1010 static void import_marks(char *input_file)
1011 {
1012         char line[512];
1013         FILE *f = xfopen(input_file, "r");
1014
1015         while (fgets(line, sizeof(line), f)) {
1016                 uint32_t mark;
1017                 char *line_end, *mark_end;
1018                 struct object_id oid;
1019                 struct object *object;
1020                 struct commit *commit;
1021                 enum object_type type;
1022
1023                 line_end = strchr(line, '\n');
1024                 if (line[0] != ':' || !line_end)
1025                         die("corrupt mark line: %s", line);
1026                 *line_end = '\0';
1027
1028                 mark = strtoumax(line + 1, &mark_end, 10);
1029                 if (!mark || mark_end == line + 1
1030                         || *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
1031                         die("corrupt mark line: %s", line);
1032
1033                 if (last_idnum < mark)
1034                         last_idnum = mark;
1035
1036                 type = oid_object_info(the_repository, &oid, NULL);
1037                 if (type < 0)
1038                         die("object not found: %s", oid_to_hex(&oid));
1039
1040                 if (type != OBJ_COMMIT)
1041                         /* only commits */
1042                         continue;
1043
1044                 commit = lookup_commit(the_repository, &oid);
1045                 if (!commit)
1046                         die("not a commit? can't happen: %s", oid_to_hex(&oid));
1047
1048                 object = &commit->object;
1049
1050                 if (object->flags & SHOWN)
1051                         error("Object %s already has a mark", oid_to_hex(&oid));
1052
1053                 mark_object(object, mark);
1054
1055                 object->flags |= SHOWN;
1056         }
1057         fclose(f);
1058 }
1059
1060 static void handle_deletes(void)
1061 {
1062         int i;
1063         for (i = 0; i < refspecs.nr; i++) {
1064                 struct refspec_item *refspec = &refspecs.items[i];
1065                 if (*refspec->src)
1066                         continue;
1067
1068                 printf("reset %s\nfrom %s\n\n",
1069                                 refspec->dst, oid_to_hex(&null_oid));
1070         }
1071 }
1072
1073 int cmd_fast_export(int argc, const char **argv, const char *prefix)
1074 {
1075         struct rev_info revs;
1076         struct object_array commits = OBJECT_ARRAY_INIT;
1077         struct commit *commit;
1078         char *export_filename = NULL, *import_filename = NULL;
1079         uint32_t lastimportid;
1080         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
1081         struct string_list paths_of_changed_objects = STRING_LIST_INIT_DUP;
1082         struct option options[] = {
1083                 OPT_INTEGER(0, "progress", &progress,
1084                             N_("show progress after <n> objects")),
1085                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
1086                              N_("select handling of signed tags"),
1087                              parse_opt_signed_tag_mode),
1088                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
1089                              N_("select handling of tags that tag filtered objects"),
1090                              parse_opt_tag_of_filtered_mode),
1091                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
1092                              N_("Dump marks to this file")),
1093                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
1094                              N_("Import marks from this file")),
1095                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
1096                          N_("Fake a tagger when tags lack one")),
1097                 OPT_BOOL(0, "full-tree", &full_tree,
1098                          N_("Output full tree for each commit")),
1099                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
1100                              N_("Use the done feature to terminate the stream")),
1101                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
1102                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
1103                              N_("Apply refspec to exported refs")),
1104                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1105                 OPT_BOOL(0, "reference-excluded-parents",
1106                          &reference_excluded_commits, N_("Reference parents which are not in fast-export stream by object id")),
1107                 OPT_BOOL(0, "show-original-ids", &show_original_ids,
1108                             N_("Show original object ids of blobs/commits")),
1109
1110                 OPT_END()
1111         };
1112
1113         if (argc == 1)
1114                 usage_with_options (fast_export_usage, options);
1115
1116         /* we handle encodings */
1117         git_config(git_default_config, NULL);
1118
1119         repo_init_revisions(the_repository, &revs, prefix);
1120         init_revision_sources(&revision_sources);
1121         revs.topo_order = 1;
1122         revs.sources = &revision_sources;
1123         revs.rewrite_parents = 1;
1124         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1125                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1126         argc = setup_revisions(argc, argv, &revs, NULL);
1127         if (argc > 1)
1128                 usage_with_options (fast_export_usage, options);
1129
1130         if (refspecs_list.nr) {
1131                 int i;
1132
1133                 for (i = 0; i < refspecs_list.nr; i++)
1134                         refspec_append(&refspecs, refspecs_list.items[i].string);
1135
1136                 string_list_clear(&refspecs_list, 1);
1137         }
1138
1139         if (use_done_feature)
1140                 printf("feature done\n");
1141
1142         if (import_filename)
1143                 import_marks(import_filename);
1144         lastimportid = last_idnum;
1145
1146         if (import_filename && revs.prune_data.nr)
1147                 full_tree = 1;
1148
1149         get_tags_and_duplicates(&revs.cmdline);
1150
1151         if (prepare_revision_walk(&revs))
1152                 die("revision walk setup failed");
1153         revs.diffopt.format_callback = show_filemodify;
1154         revs.diffopt.format_callback_data = &paths_of_changed_objects;
1155         revs.diffopt.flags.recursive = 1;
1156         while ((commit = get_revision(&revs))) {
1157                 if (has_unshown_parent(commit)) {
1158                         add_object_array(&commit->object, NULL, &commits);
1159                 }
1160                 else {
1161                         handle_commit(commit, &revs, &paths_of_changed_objects);
1162                         handle_tail(&commits, &revs, &paths_of_changed_objects);
1163                 }
1164         }
1165
1166         handle_tags_and_duplicates(&extra_refs);
1167         handle_tags_and_duplicates(&tag_refs);
1168         handle_deletes();
1169
1170         if (export_filename && lastimportid != last_idnum)
1171                 export_marks(export_filename);
1172
1173         if (use_done_feature)
1174                 printf("done\n");
1175
1176         refspec_clear(&refspecs);
1177
1178         return 0;
1179 }