Merge branch 'ws/grep-quiet-no-pager'
[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 "commit.h"
9 #include "object.h"
10 #include "tag.h"
11 #include "diff.h"
12 #include "diffcore.h"
13 #include "log-tree.h"
14 #include "revision.h"
15 #include "decorate.h"
16 #include "string-list.h"
17 #include "utf8.h"
18 #include "parse-options.h"
19 #include "quote.h"
20 #include "remote.h"
21 #include "blob.h"
22
23 static const char *fast_export_usage[] = {
24         N_("git fast-export [rev-list-opts]"),
25         NULL
26 };
27
28 static int progress;
29 static enum { ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = ABORT;
30 static enum { ERROR, DROP, REWRITE } tag_of_filtered_mode = ERROR;
31 static int fake_missing_tagger;
32 static int use_done_feature;
33 static int no_data;
34 static int full_tree;
35 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
36 static struct refspec *refspecs;
37 static int refspecs_nr;
38 static int anonymize;
39
40 static int parse_opt_signed_tag_mode(const struct option *opt,
41                                      const char *arg, int unset)
42 {
43         if (unset || !strcmp(arg, "abort"))
44                 signed_tag_mode = ABORT;
45         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
46                 signed_tag_mode = VERBATIM;
47         else if (!strcmp(arg, "warn"))
48                 signed_tag_mode = WARN;
49         else if (!strcmp(arg, "warn-strip"))
50                 signed_tag_mode = WARN_STRIP;
51         else if (!strcmp(arg, "strip"))
52                 signed_tag_mode = STRIP;
53         else
54                 return error("Unknown signed-tags mode: %s", arg);
55         return 0;
56 }
57
58 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
59                                           const char *arg, int unset)
60 {
61         if (unset || !strcmp(arg, "abort"))
62                 tag_of_filtered_mode = ERROR;
63         else if (!strcmp(arg, "drop"))
64                 tag_of_filtered_mode = DROP;
65         else if (!strcmp(arg, "rewrite"))
66                 tag_of_filtered_mode = REWRITE;
67         else
68                 return error("Unknown tag-of-filtered mode: %s", arg);
69         return 0;
70 }
71
72 static struct decoration idnums;
73 static uint32_t last_idnum;
74
75 static int has_unshown_parent(struct commit *commit)
76 {
77         struct commit_list *parent;
78
79         for (parent = commit->parents; parent; parent = parent->next)
80                 if (!(parent->item->object.flags & SHOWN) &&
81                     !(parent->item->object.flags & UNINTERESTING))
82                         return 1;
83         return 0;
84 }
85
86 struct anonymized_entry {
87         struct hashmap_entry hash;
88         const char *orig;
89         size_t orig_len;
90         const char *anon;
91         size_t anon_len;
92 };
93
94 static int anonymized_entry_cmp(const void *va, const void *vb,
95                                 const void *data)
96 {
97         const struct anonymized_entry *a = va, *b = vb;
98         return a->orig_len != b->orig_len ||
99                 memcmp(a->orig, b->orig, a->orig_len);
100 }
101
102 /*
103  * Basically keep a cache of X->Y so that we can repeatedly replace
104  * the same anonymized string with another. The actual generation
105  * is farmed out to the generate function.
106  */
107 static const void *anonymize_mem(struct hashmap *map,
108                                  void *(*generate)(const void *, size_t *),
109                                  const void *orig, size_t *len)
110 {
111         struct anonymized_entry key, *ret;
112
113         if (!map->cmpfn)
114                 hashmap_init(map, anonymized_entry_cmp, 0);
115
116         hashmap_entry_init(&key, memhash(orig, *len));
117         key.orig = orig;
118         key.orig_len = *len;
119         ret = hashmap_get(map, &key, NULL);
120
121         if (!ret) {
122                 ret = xmalloc(sizeof(*ret));
123                 hashmap_entry_init(&ret->hash, key.hash.hash);
124                 ret->orig = xstrdup(orig);
125                 ret->orig_len = *len;
126                 ret->anon = generate(orig, len);
127                 ret->anon_len = *len;
128                 hashmap_put(map, ret);
129         }
130
131         *len = ret->anon_len;
132         return ret->anon;
133 }
134
135 /*
136  * We anonymize each component of a path individually,
137  * so that paths a/b and a/c will share a common root.
138  * The paths are cached via anonymize_mem so that repeated
139  * lookups for "a" will yield the same value.
140  */
141 static void anonymize_path(struct strbuf *out, const char *path,
142                            struct hashmap *map,
143                            void *(*generate)(const void *, size_t *))
144 {
145         while (*path) {
146                 const char *end_of_component = strchrnul(path, '/');
147                 size_t len = end_of_component - path;
148                 const char *c = anonymize_mem(map, generate, path, &len);
149                 strbuf_add(out, c, len);
150                 path = end_of_component;
151                 if (*path)
152                         strbuf_addch(out, *path++);
153         }
154 }
155
156 /* Since intptr_t is C99, we do not use it here */
157 static inline uint32_t *mark_to_ptr(uint32_t mark)
158 {
159         return ((uint32_t *)NULL) + mark;
160 }
161
162 static inline uint32_t ptr_to_mark(void * mark)
163 {
164         return (uint32_t *)mark - (uint32_t *)NULL;
165 }
166
167 static inline void mark_object(struct object *object, uint32_t mark)
168 {
169         add_decoration(&idnums, object, mark_to_ptr(mark));
170 }
171
172 static inline void mark_next_object(struct object *object)
173 {
174         mark_object(object, ++last_idnum);
175 }
176
177 static int get_object_mark(struct object *object)
178 {
179         void *decoration = lookup_decoration(&idnums, object);
180         if (!decoration)
181                 return 0;
182         return ptr_to_mark(decoration);
183 }
184
185 static void show_progress(void)
186 {
187         static int counter = 0;
188         if (!progress)
189                 return;
190         if ((++counter % progress) == 0)
191                 printf("progress %d objects\n", counter);
192 }
193
194 /*
195  * Ideally we would want some transformation of the blob data here
196  * that is unreversible, but would still be the same size and have
197  * the same data relationship to other blobs (so that we get the same
198  * delta and packing behavior as the original). But the first and last
199  * requirements there are probably mutually exclusive, so let's take
200  * the easy way out for now, and just generate arbitrary content.
201  *
202  * There's no need to cache this result with anonymize_mem, since
203  * we already handle blob content caching with marks.
204  */
205 static char *anonymize_blob(unsigned long *size)
206 {
207         static int counter;
208         struct strbuf out = STRBUF_INIT;
209         strbuf_addf(&out, "anonymous blob %d", counter++);
210         *size = out.len;
211         return strbuf_detach(&out, NULL);
212 }
213
214 static void export_blob(const unsigned char *sha1)
215 {
216         unsigned long size;
217         enum object_type type;
218         char *buf;
219         struct object *object;
220         int eaten;
221
222         if (no_data)
223                 return;
224
225         if (is_null_sha1(sha1))
226                 return;
227
228         object = lookup_object(sha1);
229         if (object && object->flags & SHOWN)
230                 return;
231
232         if (anonymize) {
233                 buf = anonymize_blob(&size);
234                 object = (struct object *)lookup_blob(sha1);
235                 eaten = 0;
236         } else {
237                 buf = read_sha1_file(sha1, &type, &size);
238                 if (!buf)
239                         die ("Could not read blob %s", sha1_to_hex(sha1));
240                 if (check_sha1_signature(sha1, buf, size, typename(type)) < 0)
241                         die("sha1 mismatch in blob %s", sha1_to_hex(sha1));
242                 object = parse_object_buffer(sha1, type, size, buf, &eaten);
243         }
244
245         if (!object)
246                 die("Could not read blob %s", sha1_to_hex(sha1));
247
248         mark_next_object(object);
249
250         printf("blob\nmark :%"PRIu32"\ndata %lu\n", last_idnum, size);
251         if (size && fwrite(buf, size, 1, stdout) != 1)
252                 die_errno ("Could not write blob '%s'", sha1_to_hex(sha1));
253         printf("\n");
254
255         show_progress();
256
257         object->flags |= SHOWN;
258         if (!eaten)
259                 free(buf);
260 }
261
262 static int depth_first(const void *a_, const void *b_)
263 {
264         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
265         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
266         const char *name_a, *name_b;
267         int len_a, len_b, len;
268         int cmp;
269
270         name_a = a->one ? a->one->path : a->two->path;
271         name_b = b->one ? b->one->path : b->two->path;
272
273         len_a = strlen(name_a);
274         len_b = strlen(name_b);
275         len = (len_a < len_b) ? len_a : len_b;
276
277         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
278         cmp = memcmp(name_a, name_b, len);
279         if (cmp)
280                 return cmp;
281         cmp = len_b - len_a;
282         if (cmp)
283                 return cmp;
284         /*
285          * Move 'R'ename entries last so that all references of the file
286          * appear in the output before it is renamed (e.g., when a file
287          * was copied and renamed in the same commit).
288          */
289         return (a->status == 'R') - (b->status == 'R');
290 }
291
292 static void print_path_1(const char *path)
293 {
294         int need_quote = quote_c_style(path, NULL, NULL, 0);
295         if (need_quote)
296                 quote_c_style(path, NULL, stdout, 0);
297         else if (strchr(path, ' '))
298                 printf("\"%s\"", path);
299         else
300                 printf("%s", path);
301 }
302
303 static void *anonymize_path_component(const void *path, size_t *len)
304 {
305         static int counter;
306         struct strbuf out = STRBUF_INIT;
307         strbuf_addf(&out, "path%d", counter++);
308         return strbuf_detach(&out, len);
309 }
310
311 static void print_path(const char *path)
312 {
313         if (!anonymize)
314                 print_path_1(path);
315         else {
316                 static struct hashmap paths;
317                 static struct strbuf anon = STRBUF_INIT;
318
319                 anonymize_path(&anon, path, &paths, anonymize_path_component);
320                 print_path_1(anon.buf);
321                 strbuf_reset(&anon);
322         }
323 }
324
325 static void *generate_fake_sha1(const void *old, size_t *len)
326 {
327         static uint32_t counter = 1; /* avoid null sha1 */
328         unsigned char *out = xcalloc(20, 1);
329         put_be32(out + 16, counter++);
330         return out;
331 }
332
333 static const unsigned char *anonymize_sha1(const unsigned char *sha1)
334 {
335         static struct hashmap sha1s;
336         size_t len = 20;
337         return anonymize_mem(&sha1s, generate_fake_sha1, sha1, &len);
338 }
339
340 static void show_filemodify(struct diff_queue_struct *q,
341                             struct diff_options *options, void *data)
342 {
343         int i;
344
345         /*
346          * Handle files below a directory first, in case they are all deleted
347          * and the directory changes to a file or symlink.
348          */
349         qsort(q->queue, q->nr, sizeof(q->queue[0]), depth_first);
350
351         for (i = 0; i < q->nr; i++) {
352                 struct diff_filespec *ospec = q->queue[i]->one;
353                 struct diff_filespec *spec = q->queue[i]->two;
354
355                 switch (q->queue[i]->status) {
356                 case DIFF_STATUS_DELETED:
357                         printf("D ");
358                         print_path(spec->path);
359                         putchar('\n');
360                         break;
361
362                 case DIFF_STATUS_COPIED:
363                 case DIFF_STATUS_RENAMED:
364                         printf("%c ", q->queue[i]->status);
365                         print_path(ospec->path);
366                         putchar(' ');
367                         print_path(spec->path);
368                         putchar('\n');
369
370                         if (!hashcmp(ospec->sha1, spec->sha1) &&
371                             ospec->mode == spec->mode)
372                                 break;
373                         /* fallthrough */
374
375                 case DIFF_STATUS_TYPE_CHANGED:
376                 case DIFF_STATUS_MODIFIED:
377                 case DIFF_STATUS_ADDED:
378                         /*
379                          * Links refer to objects in another repositories;
380                          * output the SHA-1 verbatim.
381                          */
382                         if (no_data || S_ISGITLINK(spec->mode))
383                                 printf("M %06o %s ", spec->mode,
384                                        sha1_to_hex(anonymize ?
385                                                    anonymize_sha1(spec->sha1) :
386                                                    spec->sha1));
387                         else {
388                                 struct object *object = lookup_object(spec->sha1);
389                                 printf("M %06o :%d ", spec->mode,
390                                        get_object_mark(object));
391                         }
392                         print_path(spec->path);
393                         putchar('\n');
394                         break;
395
396                 default:
397                         die("Unexpected comparison status '%c' for %s, %s",
398                                 q->queue[i]->status,
399                                 ospec->path ? ospec->path : "none",
400                                 spec->path ? spec->path : "none");
401                 }
402         }
403 }
404
405 static const char *find_encoding(const char *begin, const char *end)
406 {
407         const char *needle = "\nencoding ";
408         char *bol, *eol;
409
410         bol = memmem(begin, end ? end - begin : strlen(begin),
411                      needle, strlen(needle));
412         if (!bol)
413                 return git_commit_encoding;
414         bol += strlen(needle);
415         eol = strchrnul(bol, '\n');
416         *eol = '\0';
417         return bol;
418 }
419
420 static void *anonymize_ref_component(const void *old, size_t *len)
421 {
422         static int counter;
423         struct strbuf out = STRBUF_INIT;
424         strbuf_addf(&out, "ref%d", counter++);
425         return strbuf_detach(&out, len);
426 }
427
428 static const char *anonymize_refname(const char *refname)
429 {
430         /*
431          * If any of these prefixes is found, we will leave it intact
432          * so that tags remain tags and so forth.
433          */
434         static const char *prefixes[] = {
435                 "refs/heads/",
436                 "refs/tags/",
437                 "refs/remotes/",
438                 "refs/"
439         };
440         static struct hashmap refs;
441         static struct strbuf anon = STRBUF_INIT;
442         int i;
443
444         /*
445          * We also leave "master" as a special case, since it does not reveal
446          * anything interesting.
447          */
448         if (!strcmp(refname, "refs/heads/master"))
449                 return refname;
450
451         strbuf_reset(&anon);
452         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
453                 if (skip_prefix(refname, prefixes[i], &refname)) {
454                         strbuf_addstr(&anon, prefixes[i]);
455                         break;
456                 }
457         }
458
459         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
460         return anon.buf;
461 }
462
463 /*
464  * We do not even bother to cache commit messages, as they are unlikely
465  * to be repeated verbatim, and it is not that interesting when they are.
466  */
467 static char *anonymize_commit_message(const char *old)
468 {
469         static int counter;
470         return xstrfmt("subject %d\n\nbody\n", counter++);
471 }
472
473 static struct hashmap idents;
474 static void *anonymize_ident(const void *old, size_t *len)
475 {
476         static int counter;
477         struct strbuf out = STRBUF_INIT;
478         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
479         counter++;
480         return strbuf_detach(&out, len);
481 }
482
483 /*
484  * Our strategy here is to anonymize the names and email addresses,
485  * but keep timestamps intact, as they influence things like traversal
486  * order (and by themselves should not be too revealing).
487  */
488 static void anonymize_ident_line(const char **beg, const char **end)
489 {
490         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
491         static unsigned which_buffer;
492
493         struct strbuf *out;
494         struct ident_split split;
495         const char *end_of_header;
496
497         out = &buffers[which_buffer++];
498         which_buffer %= ARRAY_SIZE(buffers);
499         strbuf_reset(out);
500
501         /* skip "committer", "author", "tagger", etc */
502         end_of_header = strchr(*beg, ' ');
503         if (!end_of_header)
504                 die("BUG: malformed line fed to anonymize_ident_line: %.*s",
505                     (int)(*end - *beg), *beg);
506         end_of_header++;
507         strbuf_add(out, *beg, end_of_header - *beg);
508
509         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
510             split.date_begin) {
511                 const char *ident;
512                 size_t len;
513
514                 len = split.mail_end - split.name_begin;
515                 ident = anonymize_mem(&idents, anonymize_ident,
516                                       split.name_begin, &len);
517                 strbuf_add(out, ident, len);
518                 strbuf_addch(out, ' ');
519                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
520         } else {
521                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
522         }
523
524         *beg = out->buf;
525         *end = out->buf + out->len;
526 }
527
528 static void handle_commit(struct commit *commit, struct rev_info *rev)
529 {
530         int saved_output_format = rev->diffopt.output_format;
531         const char *commit_buffer;
532         const char *author, *author_end, *committer, *committer_end;
533         const char *encoding, *message;
534         char *reencoded = NULL;
535         struct commit_list *p;
536         const char *refname;
537         int i;
538
539         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
540
541         parse_commit_or_die(commit);
542         commit_buffer = get_commit_buffer(commit, NULL);
543         author = strstr(commit_buffer, "\nauthor ");
544         if (!author)
545                 die ("Could not find author in commit %s",
546                      sha1_to_hex(commit->object.sha1));
547         author++;
548         author_end = strchrnul(author, '\n');
549         committer = strstr(author_end, "\ncommitter ");
550         if (!committer)
551                 die ("Could not find committer in commit %s",
552                      sha1_to_hex(commit->object.sha1));
553         committer++;
554         committer_end = strchrnul(committer, '\n');
555         message = strstr(committer_end, "\n\n");
556         encoding = find_encoding(committer_end, message);
557         if (message)
558                 message += 2;
559
560         if (commit->parents &&
561             get_object_mark(&commit->parents->item->object) != 0 &&
562             !full_tree) {
563                 parse_commit_or_die(commit->parents->item);
564                 diff_tree_sha1(commit->parents->item->tree->object.sha1,
565                                commit->tree->object.sha1, "", &rev->diffopt);
566         }
567         else
568                 diff_root_tree_sha1(commit->tree->object.sha1,
569                                     "", &rev->diffopt);
570
571         /* Export the referenced blobs, and remember the marks. */
572         for (i = 0; i < diff_queued_diff.nr; i++)
573                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
574                         export_blob(diff_queued_diff.queue[i]->two->sha1);
575
576         refname = commit->util;
577         if (anonymize) {
578                 refname = anonymize_refname(refname);
579                 anonymize_ident_line(&committer, &committer_end);
580                 anonymize_ident_line(&author, &author_end);
581         }
582
583         mark_next_object(&commit->object);
584         if (anonymize)
585                 reencoded = anonymize_commit_message(message);
586         else if (!is_encoding_utf8(encoding))
587                 reencoded = reencode_string(message, "UTF-8", encoding);
588         if (!commit->parents)
589                 printf("reset %s\n", refname);
590         printf("commit %s\nmark :%"PRIu32"\n%.*s\n%.*s\ndata %u\n%s",
591                refname, last_idnum,
592                (int)(author_end - author), author,
593                (int)(committer_end - committer), committer,
594                (unsigned)(reencoded
595                           ? strlen(reencoded) : message
596                           ? strlen(message) : 0),
597                reencoded ? reencoded : message ? message : "");
598         free(reencoded);
599         unuse_commit_buffer(commit, commit_buffer);
600
601         for (i = 0, p = commit->parents; p; p = p->next) {
602                 int mark = get_object_mark(&p->item->object);
603                 if (!mark)
604                         continue;
605                 if (i == 0)
606                         printf("from :%d\n", mark);
607                 else
608                         printf("merge :%d\n", mark);
609                 i++;
610         }
611
612         if (full_tree)
613                 printf("deleteall\n");
614         log_tree_diff_flush(rev);
615         rev->diffopt.output_format = saved_output_format;
616
617         printf("\n");
618
619         show_progress();
620 }
621
622 static void *anonymize_tag(const void *old, size_t *len)
623 {
624         static int counter;
625         struct strbuf out = STRBUF_INIT;
626         strbuf_addf(&out, "tag message %d", counter++);
627         return strbuf_detach(&out, len);
628 }
629
630 static void handle_tail(struct object_array *commits, struct rev_info *revs)
631 {
632         struct commit *commit;
633         while (commits->nr) {
634                 commit = (struct commit *)commits->objects[commits->nr - 1].item;
635                 if (has_unshown_parent(commit))
636                         return;
637                 handle_commit(commit, revs);
638                 commits->nr--;
639         }
640 }
641
642 static void handle_tag(const char *name, struct tag *tag)
643 {
644         unsigned long size;
645         enum object_type type;
646         char *buf;
647         const char *tagger, *tagger_end, *message;
648         size_t message_size = 0;
649         struct object *tagged;
650         int tagged_mark;
651         struct commit *p;
652
653         /* Trees have no identifier in fast-export output, thus we have no way
654          * to output tags of trees, tags of tags of trees, etc.  Simply omit
655          * such tags.
656          */
657         tagged = tag->tagged;
658         while (tagged->type == OBJ_TAG) {
659                 tagged = ((struct tag *)tagged)->tagged;
660         }
661         if (tagged->type == OBJ_TREE) {
662                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
663                         sha1_to_hex(tag->object.sha1));
664                 return;
665         }
666
667         buf = read_sha1_file(tag->object.sha1, &type, &size);
668         if (!buf)
669                 die ("Could not read tag %s", sha1_to_hex(tag->object.sha1));
670         message = memmem(buf, size, "\n\n", 2);
671         if (message) {
672                 message += 2;
673                 message_size = strlen(message);
674         }
675         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
676         if (!tagger) {
677                 if (fake_missing_tagger)
678                         tagger = "tagger Unspecified Tagger "
679                                 "<unspecified-tagger> 0 +0000";
680                 else
681                         tagger = "";
682                 tagger_end = tagger + strlen(tagger);
683         } else {
684                 tagger++;
685                 tagger_end = strchrnul(tagger, '\n');
686                 if (anonymize)
687                         anonymize_ident_line(&tagger, &tagger_end);
688         }
689
690         if (anonymize) {
691                 name = anonymize_refname(name);
692                 if (message) {
693                         static struct hashmap tags;
694                         message = anonymize_mem(&tags, anonymize_tag,
695                                                 message, &message_size);
696                 }
697         }
698
699         /* handle signed tags */
700         if (message) {
701                 const char *signature = strstr(message,
702                                                "\n-----BEGIN PGP SIGNATURE-----\n");
703                 if (signature)
704                         switch(signed_tag_mode) {
705                         case ABORT:
706                                 die ("Encountered signed tag %s; use "
707                                      "--signed-tags=<mode> to handle it.",
708                                      sha1_to_hex(tag->object.sha1));
709                         case WARN:
710                                 warning ("Exporting signed tag %s",
711                                          sha1_to_hex(tag->object.sha1));
712                                 /* fallthru */
713                         case VERBATIM:
714                                 break;
715                         case WARN_STRIP:
716                                 warning ("Stripping signature from tag %s",
717                                          sha1_to_hex(tag->object.sha1));
718                                 /* fallthru */
719                         case STRIP:
720                                 message_size = signature + 1 - message;
721                                 break;
722                         }
723         }
724
725         /* handle tag->tagged having been filtered out due to paths specified */
726         tagged = tag->tagged;
727         tagged_mark = get_object_mark(tagged);
728         if (!tagged_mark) {
729                 switch(tag_of_filtered_mode) {
730                 case ABORT:
731                         die ("Tag %s tags unexported object; use "
732                              "--tag-of-filtered-object=<mode> to handle it.",
733                              sha1_to_hex(tag->object.sha1));
734                 case DROP:
735                         /* Ignore this tag altogether */
736                         return;
737                 case REWRITE:
738                         if (tagged->type != OBJ_COMMIT) {
739                                 die ("Tag %s tags unexported %s!",
740                                      sha1_to_hex(tag->object.sha1),
741                                      typename(tagged->type));
742                         }
743                         p = (struct commit *)tagged;
744                         for (;;) {
745                                 if (p->parents && p->parents->next)
746                                         break;
747                                 if (p->object.flags & UNINTERESTING)
748                                         break;
749                                 if (!(p->object.flags & TREESAME))
750                                         break;
751                                 if (!p->parents)
752                                         die ("Can't find replacement commit for tag %s\n",
753                                              sha1_to_hex(tag->object.sha1));
754                                 p = p->parents->item;
755                         }
756                         tagged_mark = get_object_mark(&p->object);
757                 }
758         }
759
760         if (starts_with(name, "refs/tags/"))
761                 name += 10;
762         printf("tag %s\nfrom :%d\n%.*s%sdata %d\n%.*s\n",
763                name, tagged_mark,
764                (int)(tagger_end - tagger), tagger,
765                tagger == tagger_end ? "" : "\n",
766                (int)message_size, (int)message_size, message ? message : "");
767 }
768
769 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
770 {
771         switch (e->item->type) {
772         case OBJ_COMMIT:
773                 return (struct commit *)e->item;
774         case OBJ_TAG: {
775                 struct tag *tag = (struct tag *)e->item;
776
777                 /* handle nested tags */
778                 while (tag && tag->object.type == OBJ_TAG) {
779                         parse_object(tag->object.sha1);
780                         string_list_append(&extra_refs, full_name)->util = tag;
781                         tag = (struct tag *)tag->tagged;
782                 }
783                 if (!tag)
784                         die("Tag %s points nowhere?", e->name);
785                 return (struct commit *)tag;
786                 break;
787         }
788         default:
789                 return NULL;
790         }
791 }
792
793 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
794 {
795         int i;
796
797         for (i = 0; i < info->nr; i++) {
798                 struct rev_cmdline_entry *e = info->rev + i;
799                 unsigned char sha1[20];
800                 struct commit *commit;
801                 char *full_name;
802
803                 if (e->flags & UNINTERESTING)
804                         continue;
805
806                 if (dwim_ref(e->name, strlen(e->name), sha1, &full_name) != 1)
807                         continue;
808
809                 if (refspecs) {
810                         char *private;
811                         private = apply_refspecs(refspecs, refspecs_nr, full_name);
812                         if (private) {
813                                 free(full_name);
814                                 full_name = private;
815                         }
816                 }
817
818                 commit = get_commit(e, full_name);
819                 if (!commit) {
820                         warning("%s: Unexpected object of type %s, skipping.",
821                                 e->name,
822                                 typename(e->item->type));
823                         continue;
824                 }
825
826                 switch(commit->object.type) {
827                 case OBJ_COMMIT:
828                         break;
829                 case OBJ_BLOB:
830                         export_blob(commit->object.sha1);
831                         continue;
832                 default: /* OBJ_TAG (nested tags) is already handled */
833                         warning("Tag points to object of unexpected type %s, skipping.",
834                                 typename(commit->object.type));
835                         continue;
836                 }
837
838                 /*
839                  * This ref will not be updated through a commit, lets make
840                  * sure it gets properly updated eventually.
841                  */
842                 if (commit->util || commit->object.flags & SHOWN)
843                         string_list_append(&extra_refs, full_name)->util = commit;
844                 if (!commit->util)
845                         commit->util = full_name;
846         }
847 }
848
849 static void handle_tags_and_duplicates(void)
850 {
851         struct commit *commit;
852         int i;
853
854         for (i = extra_refs.nr - 1; i >= 0; i--) {
855                 const char *name = extra_refs.items[i].string;
856                 struct object *object = extra_refs.items[i].util;
857                 switch (object->type) {
858                 case OBJ_TAG:
859                         handle_tag(name, (struct tag *)object);
860                         break;
861                 case OBJ_COMMIT:
862                         if (anonymize)
863                                 name = anonymize_refname(name);
864                         /* create refs pointing to already seen commits */
865                         commit = (struct commit *)object;
866                         printf("reset %s\nfrom :%d\n\n", name,
867                                get_object_mark(&commit->object));
868                         show_progress();
869                         break;
870                 }
871         }
872 }
873
874 static void export_marks(char *file)
875 {
876         unsigned int i;
877         uint32_t mark;
878         struct object_decoration *deco = idnums.hash;
879         FILE *f;
880         int e = 0;
881
882         f = fopen(file, "w");
883         if (!f)
884                 die_errno("Unable to open marks file %s for writing.", file);
885
886         for (i = 0; i < idnums.size; i++) {
887                 if (deco->base && deco->base->type == 1) {
888                         mark = ptr_to_mark(deco->decoration);
889                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
890                                 sha1_to_hex(deco->base->sha1)) < 0) {
891                             e = 1;
892                             break;
893                         }
894                 }
895                 deco++;
896         }
897
898         e |= ferror(f);
899         e |= fclose(f);
900         if (e)
901                 error("Unable to write marks file %s.", file);
902 }
903
904 static void import_marks(char *input_file)
905 {
906         char line[512];
907         FILE *f = fopen(input_file, "r");
908         if (!f)
909                 die_errno("cannot read '%s'", input_file);
910
911         while (fgets(line, sizeof(line), f)) {
912                 uint32_t mark;
913                 char *line_end, *mark_end;
914                 unsigned char sha1[20];
915                 struct object *object;
916                 struct commit *commit;
917                 enum object_type type;
918
919                 line_end = strchr(line, '\n');
920                 if (line[0] != ':' || !line_end)
921                         die("corrupt mark line: %s", line);
922                 *line_end = '\0';
923
924                 mark = strtoumax(line + 1, &mark_end, 10);
925                 if (!mark || mark_end == line + 1
926                         || *mark_end != ' ' || get_sha1_hex(mark_end + 1, sha1))
927                         die("corrupt mark line: %s", line);
928
929                 if (last_idnum < mark)
930                         last_idnum = mark;
931
932                 type = sha1_object_info(sha1, NULL);
933                 if (type < 0)
934                         die("object not found: %s", sha1_to_hex(sha1));
935
936                 if (type != OBJ_COMMIT)
937                         /* only commits */
938                         continue;
939
940                 commit = lookup_commit(sha1);
941                 if (!commit)
942                         die("not a commit? can't happen: %s", sha1_to_hex(sha1));
943
944                 object = &commit->object;
945
946                 if (object->flags & SHOWN)
947                         error("Object %s already has a mark", sha1_to_hex(sha1));
948
949                 mark_object(object, mark);
950
951                 object->flags |= SHOWN;
952         }
953         fclose(f);
954 }
955
956 static void handle_deletes(void)
957 {
958         int i;
959         for (i = 0; i < refspecs_nr; i++) {
960                 struct refspec *refspec = &refspecs[i];
961                 if (*refspec->src)
962                         continue;
963
964                 printf("reset %s\nfrom %s\n\n",
965                                 refspec->dst, sha1_to_hex(null_sha1));
966         }
967 }
968
969 int cmd_fast_export(int argc, const char **argv, const char *prefix)
970 {
971         struct rev_info revs;
972         struct object_array commits = OBJECT_ARRAY_INIT;
973         struct commit *commit;
974         char *export_filename = NULL, *import_filename = NULL;
975         uint32_t lastimportid;
976         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
977         struct option options[] = {
978                 OPT_INTEGER(0, "progress", &progress,
979                             N_("show progress after <n> objects")),
980                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
981                              N_("select handling of signed tags"),
982                              parse_opt_signed_tag_mode),
983                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
984                              N_("select handling of tags that tag filtered objects"),
985                              parse_opt_tag_of_filtered_mode),
986                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
987                              N_("Dump marks to this file")),
988                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
989                              N_("Import marks from this file")),
990                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
991                          N_("Fake a tagger when tags lack one")),
992                 OPT_BOOL(0, "full-tree", &full_tree,
993                          N_("Output full tree for each commit")),
994                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
995                              N_("Use the done feature to terminate the stream")),
996                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
997                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
998                              N_("Apply refspec to exported refs")),
999                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1000                 OPT_END()
1001         };
1002
1003         if (argc == 1)
1004                 usage_with_options (fast_export_usage, options);
1005
1006         /* we handle encodings */
1007         git_config(git_default_config, NULL);
1008
1009         init_revisions(&revs, prefix);
1010         revs.topo_order = 1;
1011         revs.show_source = 1;
1012         revs.rewrite_parents = 1;
1013         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1014                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1015         argc = setup_revisions(argc, argv, &revs, NULL);
1016         if (argc > 1)
1017                 usage_with_options (fast_export_usage, options);
1018
1019         if (refspecs_list.nr) {
1020                 const char **refspecs_str;
1021                 int i;
1022
1023                 refspecs_str = xmalloc(sizeof(*refspecs_str) * refspecs_list.nr);
1024                 for (i = 0; i < refspecs_list.nr; i++)
1025                         refspecs_str[i] = refspecs_list.items[i].string;
1026
1027                 refspecs_nr = refspecs_list.nr;
1028                 refspecs = parse_fetch_refspec(refspecs_nr, refspecs_str);
1029
1030                 string_list_clear(&refspecs_list, 1);
1031                 free(refspecs_str);
1032         }
1033
1034         if (use_done_feature)
1035                 printf("feature done\n");
1036
1037         if (import_filename)
1038                 import_marks(import_filename);
1039         lastimportid = last_idnum;
1040
1041         if (import_filename && revs.prune_data.nr)
1042                 full_tree = 1;
1043
1044         get_tags_and_duplicates(&revs.cmdline);
1045
1046         if (prepare_revision_walk(&revs))
1047                 die("revision walk setup failed");
1048         revs.diffopt.format_callback = show_filemodify;
1049         DIFF_OPT_SET(&revs.diffopt, RECURSIVE);
1050         while ((commit = get_revision(&revs))) {
1051                 if (has_unshown_parent(commit)) {
1052                         add_object_array(&commit->object, NULL, &commits);
1053                 }
1054                 else {
1055                         handle_commit(commit, &revs);
1056                         handle_tail(&commits, &revs);
1057                 }
1058         }
1059
1060         handle_tags_and_duplicates();
1061         handle_deletes();
1062
1063         if (export_filename && lastimportid != last_idnum)
1064                 export_marks(export_filename);
1065
1066         if (use_done_feature)
1067                 printf("done\n");
1068
1069         free_refspec(refspecs_nr, refspecs);
1070
1071         return 0;
1072 }