Merge branch 'jk/diff-blob' into maint
[git] / 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 "commit.h"
11 #include "object.h"
12 #include "tag.h"
13 #include "diff.h"
14 #include "diffcore.h"
15 #include "log-tree.h"
16 #include "revision.h"
17 #include "decorate.h"
18 #include "string-list.h"
19 #include "utf8.h"
20 #include "parse-options.h"
21 #include "quote.h"
22 #include "remote.h"
23 #include "blob.h"
24
25 static const char *fast_export_usage[] = {
26         N_("git fast-export [rev-list-opts]"),
27         NULL
28 };
29
30 static int progress;
31 static enum { ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = ABORT;
32 static enum { ERROR, DROP, REWRITE } tag_of_filtered_mode = ERROR;
33 static int fake_missing_tagger;
34 static int use_done_feature;
35 static int no_data;
36 static int full_tree;
37 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
38 static struct refspec *refspecs;
39 static int refspecs_nr;
40 static int anonymize;
41
42 static int parse_opt_signed_tag_mode(const struct option *opt,
43                                      const char *arg, int unset)
44 {
45         if (unset || !strcmp(arg, "abort"))
46                 signed_tag_mode = ABORT;
47         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
48                 signed_tag_mode = VERBATIM;
49         else if (!strcmp(arg, "warn"))
50                 signed_tag_mode = WARN;
51         else if (!strcmp(arg, "warn-strip"))
52                 signed_tag_mode = WARN_STRIP;
53         else if (!strcmp(arg, "strip"))
54                 signed_tag_mode = STRIP;
55         else
56                 return error("Unknown signed-tags mode: %s", arg);
57         return 0;
58 }
59
60 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
61                                           const char *arg, int unset)
62 {
63         if (unset || !strcmp(arg, "abort"))
64                 tag_of_filtered_mode = ERROR;
65         else if (!strcmp(arg, "drop"))
66                 tag_of_filtered_mode = DROP;
67         else if (!strcmp(arg, "rewrite"))
68                 tag_of_filtered_mode = REWRITE;
69         else
70                 return error("Unknown tag-of-filtered mode: %s", arg);
71         return 0;
72 }
73
74 static struct decoration idnums;
75 static uint32_t last_idnum;
76
77 static int has_unshown_parent(struct commit *commit)
78 {
79         struct commit_list *parent;
80
81         for (parent = commit->parents; parent; parent = parent->next)
82                 if (!(parent->item->object.flags & SHOWN) &&
83                     !(parent->item->object.flags & UNINTERESTING))
84                         return 1;
85         return 0;
86 }
87
88 struct anonymized_entry {
89         struct hashmap_entry hash;
90         const char *orig;
91         size_t orig_len;
92         const char *anon;
93         size_t anon_len;
94 };
95
96 static int anonymized_entry_cmp(const void *unused_cmp_data,
97                                 const void *va, const void *vb,
98                                 const void *unused_keydata)
99 {
100         const struct anonymized_entry *a = va, *b = vb;
101         return a->orig_len != b->orig_len ||
102                 memcmp(a->orig, b->orig, a->orig_len);
103 }
104
105 /*
106  * Basically keep a cache of X->Y so that we can repeatedly replace
107  * the same anonymized string with another. The actual generation
108  * is farmed out to the generate function.
109  */
110 static const void *anonymize_mem(struct hashmap *map,
111                                  void *(*generate)(const void *, size_t *),
112                                  const void *orig, size_t *len)
113 {
114         struct anonymized_entry key, *ret;
115
116         if (!map->cmpfn)
117                 hashmap_init(map, anonymized_entry_cmp, NULL, 0);
118
119         hashmap_entry_init(&key, memhash(orig, *len));
120         key.orig = orig;
121         key.orig_len = *len;
122         ret = hashmap_get(map, &key, NULL);
123
124         if (!ret) {
125                 ret = xmalloc(sizeof(*ret));
126                 hashmap_entry_init(&ret->hash, key.hash.hash);
127                 ret->orig = xstrdup(orig);
128                 ret->orig_len = *len;
129                 ret->anon = generate(orig, len);
130                 ret->anon_len = *len;
131                 hashmap_put(map, ret);
132         }
133
134         *len = ret->anon_len;
135         return ret->anon;
136 }
137
138 /*
139  * We anonymize each component of a path individually,
140  * so that paths a/b and a/c will share a common root.
141  * The paths are cached via anonymize_mem so that repeated
142  * lookups for "a" will yield the same value.
143  */
144 static void anonymize_path(struct strbuf *out, const char *path,
145                            struct hashmap *map,
146                            void *(*generate)(const void *, size_t *))
147 {
148         while (*path) {
149                 const char *end_of_component = strchrnul(path, '/');
150                 size_t len = end_of_component - path;
151                 const char *c = anonymize_mem(map, generate, path, &len);
152                 strbuf_add(out, c, len);
153                 path = end_of_component;
154                 if (*path)
155                         strbuf_addch(out, *path++);
156         }
157 }
158
159 /* Since intptr_t is C99, we do not use it here */
160 static inline uint32_t *mark_to_ptr(uint32_t mark)
161 {
162         return ((uint32_t *)NULL) + mark;
163 }
164
165 static inline uint32_t ptr_to_mark(void * mark)
166 {
167         return (uint32_t *)mark - (uint32_t *)NULL;
168 }
169
170 static inline void mark_object(struct object *object, uint32_t mark)
171 {
172         add_decoration(&idnums, object, mark_to_ptr(mark));
173 }
174
175 static inline void mark_next_object(struct object *object)
176 {
177         mark_object(object, ++last_idnum);
178 }
179
180 static int get_object_mark(struct object *object)
181 {
182         void *decoration = lookup_decoration(&idnums, object);
183         if (!decoration)
184                 return 0;
185         return ptr_to_mark(decoration);
186 }
187
188 static void show_progress(void)
189 {
190         static int counter = 0;
191         if (!progress)
192                 return;
193         if ((++counter % progress) == 0)
194                 printf("progress %d objects\n", counter);
195 }
196
197 /*
198  * Ideally we would want some transformation of the blob data here
199  * that is unreversible, but would still be the same size and have
200  * the same data relationship to other blobs (so that we get the same
201  * delta and packing behavior as the original). But the first and last
202  * requirements there are probably mutually exclusive, so let's take
203  * the easy way out for now, and just generate arbitrary content.
204  *
205  * There's no need to cache this result with anonymize_mem, since
206  * we already handle blob content caching with marks.
207  */
208 static char *anonymize_blob(unsigned long *size)
209 {
210         static int counter;
211         struct strbuf out = STRBUF_INIT;
212         strbuf_addf(&out, "anonymous blob %d", counter++);
213         *size = out.len;
214         return strbuf_detach(&out, NULL);
215 }
216
217 static void export_blob(const struct object_id *oid)
218 {
219         unsigned long size;
220         enum object_type type;
221         char *buf;
222         struct object *object;
223         int eaten;
224
225         if (no_data)
226                 return;
227
228         if (is_null_oid(oid))
229                 return;
230
231         object = lookup_object(oid->hash);
232         if (object && object->flags & SHOWN)
233                 return;
234
235         if (anonymize) {
236                 buf = anonymize_blob(&size);
237                 object = (struct object *)lookup_blob(oid);
238                 eaten = 0;
239         } else {
240                 buf = read_sha1_file(oid->hash, &type, &size);
241                 if (!buf)
242                         die ("Could not read blob %s", oid_to_hex(oid));
243                 if (check_sha1_signature(oid->hash, buf, size, typename(type)) < 0)
244                         die("sha1 mismatch in blob %s", oid_to_hex(oid));
245                 object = parse_object_buffer(oid, type, size, buf, &eaten);
246         }
247
248         if (!object)
249                 die("Could not read blob %s", oid_to_hex(oid));
250
251         mark_next_object(object);
252
253         printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
254         if (size && fwrite(buf, size, 1, stdout) != 1)
255                 die_errno ("Could not write blob '%s'", oid_to_hex(oid));
256         printf("\n");
257
258         show_progress();
259
260         object->flags |= SHOWN;
261         if (!eaten)
262                 free(buf);
263 }
264
265 static int depth_first(const void *a_, const void *b_)
266 {
267         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
268         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
269         const char *name_a, *name_b;
270         int len_a, len_b, len;
271         int cmp;
272
273         name_a = a->one ? a->one->path : a->two->path;
274         name_b = b->one ? b->one->path : b->two->path;
275
276         len_a = strlen(name_a);
277         len_b = strlen(name_b);
278         len = (len_a < len_b) ? len_a : len_b;
279
280         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
281         cmp = memcmp(name_a, name_b, len);
282         if (cmp)
283                 return cmp;
284         cmp = len_b - len_a;
285         if (cmp)
286                 return cmp;
287         /*
288          * Move 'R'ename entries last so that all references of the file
289          * appear in the output before it is renamed (e.g., when a file
290          * was copied and renamed in the same commit).
291          */
292         return (a->status == 'R') - (b->status == 'R');
293 }
294
295 static void print_path_1(const char *path)
296 {
297         int need_quote = quote_c_style(path, NULL, NULL, 0);
298         if (need_quote)
299                 quote_c_style(path, NULL, stdout, 0);
300         else if (strchr(path, ' '))
301                 printf("\"%s\"", path);
302         else
303                 printf("%s", path);
304 }
305
306 static void *anonymize_path_component(const void *path, size_t *len)
307 {
308         static int counter;
309         struct strbuf out = STRBUF_INIT;
310         strbuf_addf(&out, "path%d", counter++);
311         return strbuf_detach(&out, len);
312 }
313
314 static void print_path(const char *path)
315 {
316         if (!anonymize)
317                 print_path_1(path);
318         else {
319                 static struct hashmap paths;
320                 static struct strbuf anon = STRBUF_INIT;
321
322                 anonymize_path(&anon, path, &paths, anonymize_path_component);
323                 print_path_1(anon.buf);
324                 strbuf_reset(&anon);
325         }
326 }
327
328 static void *generate_fake_oid(const void *old, size_t *len)
329 {
330         static uint32_t counter = 1; /* avoid null sha1 */
331         unsigned char *out = xcalloc(GIT_SHA1_RAWSZ, 1);
332         put_be32(out + GIT_SHA1_RAWSZ - 4, counter++);
333         return out;
334 }
335
336 static const unsigned char *anonymize_sha1(const struct object_id *oid)
337 {
338         static struct hashmap sha1s;
339         size_t len = GIT_SHA1_RAWSZ;
340         return anonymize_mem(&sha1s, generate_fake_oid, oid, &len);
341 }
342
343 static void show_filemodify(struct diff_queue_struct *q,
344                             struct diff_options *options, void *data)
345 {
346         int i;
347
348         /*
349          * Handle files below a directory first, in case they are all deleted
350          * and the directory changes to a file or symlink.
351          */
352         QSORT(q->queue, q->nr, depth_first);
353
354         for (i = 0; i < q->nr; i++) {
355                 struct diff_filespec *ospec = q->queue[i]->one;
356                 struct diff_filespec *spec = q->queue[i]->two;
357
358                 switch (q->queue[i]->status) {
359                 case DIFF_STATUS_DELETED:
360                         printf("D ");
361                         print_path(spec->path);
362                         putchar('\n');
363                         break;
364
365                 case DIFF_STATUS_COPIED:
366                 case DIFF_STATUS_RENAMED:
367                         printf("%c ", q->queue[i]->status);
368                         print_path(ospec->path);
369                         putchar(' ');
370                         print_path(spec->path);
371                         putchar('\n');
372
373                         if (!oidcmp(&ospec->oid, &spec->oid) &&
374                             ospec->mode == spec->mode)
375                                 break;
376                         /* fallthrough */
377
378                 case DIFF_STATUS_TYPE_CHANGED:
379                 case DIFF_STATUS_MODIFIED:
380                 case DIFF_STATUS_ADDED:
381                         /*
382                          * Links refer to objects in another repositories;
383                          * output the SHA-1 verbatim.
384                          */
385                         if (no_data || S_ISGITLINK(spec->mode))
386                                 printf("M %06o %s ", spec->mode,
387                                        sha1_to_hex(anonymize ?
388                                                    anonymize_sha1(&spec->oid) :
389                                                    spec->oid.hash));
390                         else {
391                                 struct object *object = lookup_object(spec->oid.hash);
392                                 printf("M %06o :%d ", spec->mode,
393                                        get_object_mark(object));
394                         }
395                         print_path(spec->path);
396                         putchar('\n');
397                         break;
398
399                 default:
400                         die("Unexpected comparison status '%c' for %s, %s",
401                                 q->queue[i]->status,
402                                 ospec->path ? ospec->path : "none",
403                                 spec->path ? spec->path : "none");
404                 }
405         }
406 }
407
408 static const char *find_encoding(const char *begin, const char *end)
409 {
410         const char *needle = "\nencoding ";
411         char *bol, *eol;
412
413         bol = memmem(begin, end ? end - begin : strlen(begin),
414                      needle, strlen(needle));
415         if (!bol)
416                 return git_commit_encoding;
417         bol += strlen(needle);
418         eol = strchrnul(bol, '\n');
419         *eol = '\0';
420         return bol;
421 }
422
423 static void *anonymize_ref_component(const void *old, size_t *len)
424 {
425         static int counter;
426         struct strbuf out = STRBUF_INIT;
427         strbuf_addf(&out, "ref%d", counter++);
428         return strbuf_detach(&out, len);
429 }
430
431 static const char *anonymize_refname(const char *refname)
432 {
433         /*
434          * If any of these prefixes is found, we will leave it intact
435          * so that tags remain tags and so forth.
436          */
437         static const char *prefixes[] = {
438                 "refs/heads/",
439                 "refs/tags/",
440                 "refs/remotes/",
441                 "refs/"
442         };
443         static struct hashmap refs;
444         static struct strbuf anon = STRBUF_INIT;
445         int i;
446
447         /*
448          * We also leave "master" as a special case, since it does not reveal
449          * anything interesting.
450          */
451         if (!strcmp(refname, "refs/heads/master"))
452                 return refname;
453
454         strbuf_reset(&anon);
455         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
456                 if (skip_prefix(refname, prefixes[i], &refname)) {
457                         strbuf_addstr(&anon, prefixes[i]);
458                         break;
459                 }
460         }
461
462         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
463         return anon.buf;
464 }
465
466 /*
467  * We do not even bother to cache commit messages, as they are unlikely
468  * to be repeated verbatim, and it is not that interesting when they are.
469  */
470 static char *anonymize_commit_message(const char *old)
471 {
472         static int counter;
473         return xstrfmt("subject %d\n\nbody\n", counter++);
474 }
475
476 static struct hashmap idents;
477 static void *anonymize_ident(const void *old, size_t *len)
478 {
479         static int counter;
480         struct strbuf out = STRBUF_INIT;
481         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
482         counter++;
483         return strbuf_detach(&out, len);
484 }
485
486 /*
487  * Our strategy here is to anonymize the names and email addresses,
488  * but keep timestamps intact, as they influence things like traversal
489  * order (and by themselves should not be too revealing).
490  */
491 static void anonymize_ident_line(const char **beg, const char **end)
492 {
493         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
494         static unsigned which_buffer;
495
496         struct strbuf *out;
497         struct ident_split split;
498         const char *end_of_header;
499
500         out = &buffers[which_buffer++];
501         which_buffer %= ARRAY_SIZE(buffers);
502         strbuf_reset(out);
503
504         /* skip "committer", "author", "tagger", etc */
505         end_of_header = strchr(*beg, ' ');
506         if (!end_of_header)
507                 die("BUG: malformed line fed to anonymize_ident_line: %.*s",
508                     (int)(*end - *beg), *beg);
509         end_of_header++;
510         strbuf_add(out, *beg, end_of_header - *beg);
511
512         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
513             split.date_begin) {
514                 const char *ident;
515                 size_t len;
516
517                 len = split.mail_end - split.name_begin;
518                 ident = anonymize_mem(&idents, anonymize_ident,
519                                       split.name_begin, &len);
520                 strbuf_add(out, ident, len);
521                 strbuf_addch(out, ' ');
522                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
523         } else {
524                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
525         }
526
527         *beg = out->buf;
528         *end = out->buf + out->len;
529 }
530
531 static void handle_commit(struct commit *commit, struct rev_info *rev)
532 {
533         int saved_output_format = rev->diffopt.output_format;
534         const char *commit_buffer;
535         const char *author, *author_end, *committer, *committer_end;
536         const char *encoding, *message;
537         char *reencoded = NULL;
538         struct commit_list *p;
539         const char *refname;
540         int i;
541
542         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
543
544         parse_commit_or_die(commit);
545         commit_buffer = get_commit_buffer(commit, NULL);
546         author = strstr(commit_buffer, "\nauthor ");
547         if (!author)
548                 die ("Could not find author in commit %s",
549                      oid_to_hex(&commit->object.oid));
550         author++;
551         author_end = strchrnul(author, '\n');
552         committer = strstr(author_end, "\ncommitter ");
553         if (!committer)
554                 die ("Could not find committer in commit %s",
555                      oid_to_hex(&commit->object.oid));
556         committer++;
557         committer_end = strchrnul(committer, '\n');
558         message = strstr(committer_end, "\n\n");
559         encoding = find_encoding(committer_end, message);
560         if (message)
561                 message += 2;
562
563         if (commit->parents &&
564             get_object_mark(&commit->parents->item->object) != 0 &&
565             !full_tree) {
566                 parse_commit_or_die(commit->parents->item);
567                 diff_tree_oid(&commit->parents->item->tree->object.oid,
568                               &commit->tree->object.oid, "", &rev->diffopt);
569         }
570         else
571                 diff_root_tree_oid(&commit->tree->object.oid,
572                                    "", &rev->diffopt);
573
574         /* Export the referenced blobs, and remember the marks. */
575         for (i = 0; i < diff_queued_diff.nr; i++)
576                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
577                         export_blob(&diff_queued_diff.queue[i]->two->oid);
578
579         refname = commit->util;
580         if (anonymize) {
581                 refname = anonymize_refname(refname);
582                 anonymize_ident_line(&committer, &committer_end);
583                 anonymize_ident_line(&author, &author_end);
584         }
585
586         mark_next_object(&commit->object);
587         if (anonymize)
588                 reencoded = anonymize_commit_message(message);
589         else if (!is_encoding_utf8(encoding))
590                 reencoded = reencode_string(message, "UTF-8", encoding);
591         if (!commit->parents)
592                 printf("reset %s\n", refname);
593         printf("commit %s\nmark :%"PRIu32"\n%.*s\n%.*s\ndata %u\n%s",
594                refname, last_idnum,
595                (int)(author_end - author), author,
596                (int)(committer_end - committer), committer,
597                (unsigned)(reencoded
598                           ? strlen(reencoded) : message
599                           ? strlen(message) : 0),
600                reencoded ? reencoded : message ? message : "");
601         free(reencoded);
602         unuse_commit_buffer(commit, commit_buffer);
603
604         for (i = 0, p = commit->parents; p; p = p->next) {
605                 int mark = get_object_mark(&p->item->object);
606                 if (!mark)
607                         continue;
608                 if (i == 0)
609                         printf("from :%d\n", mark);
610                 else
611                         printf("merge :%d\n", mark);
612                 i++;
613         }
614
615         if (full_tree)
616                 printf("deleteall\n");
617         log_tree_diff_flush(rev);
618         rev->diffopt.output_format = saved_output_format;
619
620         printf("\n");
621
622         show_progress();
623 }
624
625 static void *anonymize_tag(const void *old, size_t *len)
626 {
627         static int counter;
628         struct strbuf out = STRBUF_INIT;
629         strbuf_addf(&out, "tag message %d", counter++);
630         return strbuf_detach(&out, len);
631 }
632
633 static void handle_tail(struct object_array *commits, struct rev_info *revs)
634 {
635         struct commit *commit;
636         while (commits->nr) {
637                 commit = (struct commit *)commits->objects[commits->nr - 1].item;
638                 if (has_unshown_parent(commit))
639                         return;
640                 handle_commit(commit, revs);
641                 commits->nr--;
642         }
643 }
644
645 static void handle_tag(const char *name, struct tag *tag)
646 {
647         unsigned long size;
648         enum object_type type;
649         char *buf;
650         const char *tagger, *tagger_end, *message;
651         size_t message_size = 0;
652         struct object *tagged;
653         int tagged_mark;
654         struct commit *p;
655
656         /* Trees have no identifier in fast-export output, thus we have no way
657          * to output tags of trees, tags of tags of trees, etc.  Simply omit
658          * such tags.
659          */
660         tagged = tag->tagged;
661         while (tagged->type == OBJ_TAG) {
662                 tagged = ((struct tag *)tagged)->tagged;
663         }
664         if (tagged->type == OBJ_TREE) {
665                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
666                         oid_to_hex(&tag->object.oid));
667                 return;
668         }
669
670         buf = read_sha1_file(tag->object.oid.hash, &type, &size);
671         if (!buf)
672                 die ("Could not read tag %s", oid_to_hex(&tag->object.oid));
673         message = memmem(buf, size, "\n\n", 2);
674         if (message) {
675                 message += 2;
676                 message_size = strlen(message);
677         }
678         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
679         if (!tagger) {
680                 if (fake_missing_tagger)
681                         tagger = "tagger Unspecified Tagger "
682                                 "<unspecified-tagger> 0 +0000";
683                 else
684                         tagger = "";
685                 tagger_end = tagger + strlen(tagger);
686         } else {
687                 tagger++;
688                 tagger_end = strchrnul(tagger, '\n');
689                 if (anonymize)
690                         anonymize_ident_line(&tagger, &tagger_end);
691         }
692
693         if (anonymize) {
694                 name = anonymize_refname(name);
695                 if (message) {
696                         static struct hashmap tags;
697                         message = anonymize_mem(&tags, anonymize_tag,
698                                                 message, &message_size);
699                 }
700         }
701
702         /* handle signed tags */
703         if (message) {
704                 const char *signature = strstr(message,
705                                                "\n-----BEGIN PGP SIGNATURE-----\n");
706                 if (signature)
707                         switch(signed_tag_mode) {
708                         case ABORT:
709                                 die ("Encountered signed tag %s; use "
710                                      "--signed-tags=<mode> to handle it.",
711                                      oid_to_hex(&tag->object.oid));
712                         case WARN:
713                                 warning ("Exporting signed tag %s",
714                                          oid_to_hex(&tag->object.oid));
715                                 /* fallthru */
716                         case VERBATIM:
717                                 break;
718                         case WARN_STRIP:
719                                 warning ("Stripping signature from tag %s",
720                                          oid_to_hex(&tag->object.oid));
721                                 /* fallthru */
722                         case STRIP:
723                                 message_size = signature + 1 - message;
724                                 break;
725                         }
726         }
727
728         /* handle tag->tagged having been filtered out due to paths specified */
729         tagged = tag->tagged;
730         tagged_mark = get_object_mark(tagged);
731         if (!tagged_mark) {
732                 switch(tag_of_filtered_mode) {
733                 case ABORT:
734                         die ("Tag %s tags unexported object; use "
735                              "--tag-of-filtered-object=<mode> to handle it.",
736                              oid_to_hex(&tag->object.oid));
737                 case DROP:
738                         /* Ignore this tag altogether */
739                         free(buf);
740                         return;
741                 case REWRITE:
742                         if (tagged->type != OBJ_COMMIT) {
743                                 die ("Tag %s tags unexported %s!",
744                                      oid_to_hex(&tag->object.oid),
745                                      typename(tagged->type));
746                         }
747                         p = (struct commit *)tagged;
748                         for (;;) {
749                                 if (p->parents && p->parents->next)
750                                         break;
751                                 if (p->object.flags & UNINTERESTING)
752                                         break;
753                                 if (!(p->object.flags & TREESAME))
754                                         break;
755                                 if (!p->parents)
756                                         die ("Can't find replacement commit for tag %s\n",
757                                              oid_to_hex(&tag->object.oid));
758                                 p = p->parents->item;
759                         }
760                         tagged_mark = get_object_mark(&p->object);
761                 }
762         }
763
764         if (starts_with(name, "refs/tags/"))
765                 name += 10;
766         printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
767                name, tagged_mark,
768                (int)(tagger_end - tagger), tagger,
769                tagger == tagger_end ? "" : "\n",
770                (int)message_size, (int)message_size, message ? message : "");
771         free(buf);
772 }
773
774 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
775 {
776         switch (e->item->type) {
777         case OBJ_COMMIT:
778                 return (struct commit *)e->item;
779         case OBJ_TAG: {
780                 struct tag *tag = (struct tag *)e->item;
781
782                 /* handle nested tags */
783                 while (tag && tag->object.type == OBJ_TAG) {
784                         parse_object(&tag->object.oid);
785                         string_list_append(&extra_refs, full_name)->util = tag;
786                         tag = (struct tag *)tag->tagged;
787                 }
788                 if (!tag)
789                         die("Tag %s points nowhere?", e->name);
790                 return (struct commit *)tag;
791                 break;
792         }
793         default:
794                 return NULL;
795         }
796 }
797
798 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
799 {
800         int i;
801
802         for (i = 0; i < info->nr; i++) {
803                 struct rev_cmdline_entry *e = info->rev + i;
804                 struct object_id oid;
805                 struct commit *commit;
806                 char *full_name;
807
808                 if (e->flags & UNINTERESTING)
809                         continue;
810
811                 if (dwim_ref(e->name, strlen(e->name), oid.hash, &full_name) != 1)
812                         continue;
813
814                 if (refspecs) {
815                         char *private;
816                         private = apply_refspecs(refspecs, refspecs_nr, full_name);
817                         if (private) {
818                                 free(full_name);
819                                 full_name = private;
820                         }
821                 }
822
823                 commit = get_commit(e, full_name);
824                 if (!commit) {
825                         warning("%s: Unexpected object of type %s, skipping.",
826                                 e->name,
827                                 typename(e->item->type));
828                         continue;
829                 }
830
831                 switch(commit->object.type) {
832                 case OBJ_COMMIT:
833                         break;
834                 case OBJ_BLOB:
835                         export_blob(&commit->object.oid);
836                         continue;
837                 default: /* OBJ_TAG (nested tags) is already handled */
838                         warning("Tag points to object of unexpected type %s, skipping.",
839                                 typename(commit->object.type));
840                         continue;
841                 }
842
843                 /*
844                  * This ref will not be updated through a commit, lets make
845                  * sure it gets properly updated eventually.
846                  */
847                 if (commit->util || commit->object.flags & SHOWN)
848                         string_list_append(&extra_refs, full_name)->util = commit;
849                 if (!commit->util)
850                         commit->util = full_name;
851         }
852 }
853
854 static void handle_tags_and_duplicates(void)
855 {
856         struct commit *commit;
857         int i;
858
859         for (i = extra_refs.nr - 1; i >= 0; i--) {
860                 const char *name = extra_refs.items[i].string;
861                 struct object *object = extra_refs.items[i].util;
862                 switch (object->type) {
863                 case OBJ_TAG:
864                         handle_tag(name, (struct tag *)object);
865                         break;
866                 case OBJ_COMMIT:
867                         if (anonymize)
868                                 name = anonymize_refname(name);
869                         /* create refs pointing to already seen commits */
870                         commit = (struct commit *)object;
871                         printf("reset %s\nfrom :%d\n\n", name,
872                                get_object_mark(&commit->object));
873                         show_progress();
874                         break;
875                 }
876         }
877 }
878
879 static void export_marks(char *file)
880 {
881         unsigned int i;
882         uint32_t mark;
883         struct object_decoration *deco = idnums.hash;
884         FILE *f;
885         int e = 0;
886
887         f = fopen_for_writing(file);
888         if (!f)
889                 die_errno("Unable to open marks file %s for writing.", file);
890
891         for (i = 0; i < idnums.size; i++) {
892                 if (deco->base && deco->base->type == 1) {
893                         mark = ptr_to_mark(deco->decoration);
894                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
895                                 oid_to_hex(&deco->base->oid)) < 0) {
896                             e = 1;
897                             break;
898                         }
899                 }
900                 deco++;
901         }
902
903         e |= ferror(f);
904         e |= fclose(f);
905         if (e)
906                 error("Unable to write marks file %s.", file);
907 }
908
909 static void import_marks(char *input_file)
910 {
911         char line[512];
912         FILE *f = xfopen(input_file, "r");
913
914         while (fgets(line, sizeof(line), f)) {
915                 uint32_t mark;
916                 char *line_end, *mark_end;
917                 struct object_id oid;
918                 struct object *object;
919                 struct commit *commit;
920                 enum object_type type;
921
922                 line_end = strchr(line, '\n');
923                 if (line[0] != ':' || !line_end)
924                         die("corrupt mark line: %s", line);
925                 *line_end = '\0';
926
927                 mark = strtoumax(line + 1, &mark_end, 10);
928                 if (!mark || mark_end == line + 1
929                         || *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
930                         die("corrupt mark line: %s", line);
931
932                 if (last_idnum < mark)
933                         last_idnum = mark;
934
935                 type = sha1_object_info(oid.hash, NULL);
936                 if (type < 0)
937                         die("object not found: %s", oid_to_hex(&oid));
938
939                 if (type != OBJ_COMMIT)
940                         /* only commits */
941                         continue;
942
943                 commit = lookup_commit(&oid);
944                 if (!commit)
945                         die("not a commit? can't happen: %s", oid_to_hex(&oid));
946
947                 object = &commit->object;
948
949                 if (object->flags & SHOWN)
950                         error("Object %s already has a mark", oid_to_hex(&oid));
951
952                 mark_object(object, mark);
953
954                 object->flags |= SHOWN;
955         }
956         fclose(f);
957 }
958
959 static void handle_deletes(void)
960 {
961         int i;
962         for (i = 0; i < refspecs_nr; i++) {
963                 struct refspec *refspec = &refspecs[i];
964                 if (*refspec->src)
965                         continue;
966
967                 printf("reset %s\nfrom %s\n\n",
968                                 refspec->dst, sha1_to_hex(null_sha1));
969         }
970 }
971
972 int cmd_fast_export(int argc, const char **argv, const char *prefix)
973 {
974         struct rev_info revs;
975         struct object_array commits = OBJECT_ARRAY_INIT;
976         struct commit *commit;
977         char *export_filename = NULL, *import_filename = NULL;
978         uint32_t lastimportid;
979         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
980         struct option options[] = {
981                 OPT_INTEGER(0, "progress", &progress,
982                             N_("show progress after <n> objects")),
983                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
984                              N_("select handling of signed tags"),
985                              parse_opt_signed_tag_mode),
986                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
987                              N_("select handling of tags that tag filtered objects"),
988                              parse_opt_tag_of_filtered_mode),
989                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
990                              N_("Dump marks to this file")),
991                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
992                              N_("Import marks from this file")),
993                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
994                          N_("Fake a tagger when tags lack one")),
995                 OPT_BOOL(0, "full-tree", &full_tree,
996                          N_("Output full tree for each commit")),
997                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
998                              N_("Use the done feature to terminate the stream")),
999                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
1000                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
1001                              N_("Apply refspec to exported refs")),
1002                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1003                 OPT_END()
1004         };
1005
1006         if (argc == 1)
1007                 usage_with_options (fast_export_usage, options);
1008
1009         /* we handle encodings */
1010         git_config(git_default_config, NULL);
1011
1012         init_revisions(&revs, prefix);
1013         revs.topo_order = 1;
1014         revs.show_source = 1;
1015         revs.rewrite_parents = 1;
1016         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1017                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1018         argc = setup_revisions(argc, argv, &revs, NULL);
1019         if (argc > 1)
1020                 usage_with_options (fast_export_usage, options);
1021
1022         if (refspecs_list.nr) {
1023                 const char **refspecs_str;
1024                 int i;
1025
1026                 ALLOC_ARRAY(refspecs_str, refspecs_list.nr);
1027                 for (i = 0; i < refspecs_list.nr; i++)
1028                         refspecs_str[i] = refspecs_list.items[i].string;
1029
1030                 refspecs_nr = refspecs_list.nr;
1031                 refspecs = parse_fetch_refspec(refspecs_nr, refspecs_str);
1032
1033                 string_list_clear(&refspecs_list, 1);
1034                 free(refspecs_str);
1035         }
1036
1037         if (use_done_feature)
1038                 printf("feature done\n");
1039
1040         if (import_filename)
1041                 import_marks(import_filename);
1042         lastimportid = last_idnum;
1043
1044         if (import_filename && revs.prune_data.nr)
1045                 full_tree = 1;
1046
1047         get_tags_and_duplicates(&revs.cmdline);
1048
1049         if (prepare_revision_walk(&revs))
1050                 die("revision walk setup failed");
1051         revs.diffopt.format_callback = show_filemodify;
1052         DIFF_OPT_SET(&revs.diffopt, RECURSIVE);
1053         while ((commit = get_revision(&revs))) {
1054                 if (has_unshown_parent(commit)) {
1055                         add_object_array(&commit->object, NULL, &commits);
1056                 }
1057                 else {
1058                         handle_commit(commit, &revs);
1059                         handle_tail(&commits, &revs);
1060                 }
1061         }
1062
1063         handle_tags_and_duplicates();
1064         handle_deletes();
1065
1066         if (export_filename && lastimportid != last_idnum)
1067                 export_marks(export_filename);
1068
1069         if (use_done_feature)
1070                 printf("done\n");
1071
1072         free_refspec(refspecs_nr, refspecs);
1073
1074         return 0;
1075 }