Merge branch 'vn/xmmap-gently'
[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 "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 enum { REENCODE_ABORT, REENCODE_YES, REENCODE_NO } reencode_mode = REENCODE_ABORT;
37 static int fake_missing_tagger;
38 static int use_done_feature;
39 static int no_data;
40 static int full_tree;
41 static int reference_excluded_commits;
42 static int show_original_ids;
43 static struct string_list extra_refs = STRING_LIST_INIT_NODUP;
44 static struct string_list tag_refs = STRING_LIST_INIT_NODUP;
45 static struct refspec refspecs = REFSPEC_INIT_FETCH;
46 static int anonymize;
47 static struct revision_sources revision_sources;
48
49 static int parse_opt_signed_tag_mode(const struct option *opt,
50                                      const char *arg, int unset)
51 {
52         if (unset || !strcmp(arg, "abort"))
53                 signed_tag_mode = SIGNED_TAG_ABORT;
54         else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
55                 signed_tag_mode = VERBATIM;
56         else if (!strcmp(arg, "warn"))
57                 signed_tag_mode = WARN;
58         else if (!strcmp(arg, "warn-strip"))
59                 signed_tag_mode = WARN_STRIP;
60         else if (!strcmp(arg, "strip"))
61                 signed_tag_mode = STRIP;
62         else
63                 return error("Unknown signed-tags mode: %s", arg);
64         return 0;
65 }
66
67 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
68                                           const char *arg, int unset)
69 {
70         if (unset || !strcmp(arg, "abort"))
71                 tag_of_filtered_mode = TAG_FILTERING_ABORT;
72         else if (!strcmp(arg, "drop"))
73                 tag_of_filtered_mode = DROP;
74         else if (!strcmp(arg, "rewrite"))
75                 tag_of_filtered_mode = REWRITE;
76         else
77                 return error("Unknown tag-of-filtered mode: %s", arg);
78         return 0;
79 }
80
81 static int parse_opt_reencode_mode(const struct option *opt,
82                                    const char *arg, int unset)
83 {
84         if (unset) {
85                 reencode_mode = REENCODE_ABORT;
86                 return 0;
87         }
88
89         switch (git_parse_maybe_bool(arg)) {
90         case 0:
91                 reencode_mode = REENCODE_NO;
92                 break;
93         case 1:
94                 reencode_mode = REENCODE_YES;
95                 break;
96         default:
97                 if (!strcasecmp(arg, "abort"))
98                         reencode_mode = REENCODE_ABORT;
99                 else
100                         return error("Unknown reencoding mode: %s", arg);
101         }
102
103         return 0;
104 }
105
106 static struct decoration idnums;
107 static uint32_t last_idnum;
108
109 static int has_unshown_parent(struct commit *commit)
110 {
111         struct commit_list *parent;
112
113         for (parent = commit->parents; parent; parent = parent->next)
114                 if (!(parent->item->object.flags & SHOWN) &&
115                     !(parent->item->object.flags & UNINTERESTING))
116                         return 1;
117         return 0;
118 }
119
120 struct anonymized_entry {
121         struct hashmap_entry hash;
122         const char *orig;
123         size_t orig_len;
124         const char *anon;
125         size_t anon_len;
126 };
127
128 static int anonymized_entry_cmp(const void *unused_cmp_data,
129                                 const void *va, const void *vb,
130                                 const void *unused_keydata)
131 {
132         const struct anonymized_entry *a = va, *b = vb;
133         return a->orig_len != b->orig_len ||
134                 memcmp(a->orig, b->orig, a->orig_len);
135 }
136
137 /*
138  * Basically keep a cache of X->Y so that we can repeatedly replace
139  * the same anonymized string with another. The actual generation
140  * is farmed out to the generate function.
141  */
142 static const void *anonymize_mem(struct hashmap *map,
143                                  void *(*generate)(const void *, size_t *),
144                                  const void *orig, size_t *len)
145 {
146         struct anonymized_entry key, *ret;
147
148         if (!map->cmpfn)
149                 hashmap_init(map, anonymized_entry_cmp, NULL, 0);
150
151         hashmap_entry_init(&key, memhash(orig, *len));
152         key.orig = orig;
153         key.orig_len = *len;
154         ret = hashmap_get(map, &key, NULL);
155
156         if (!ret) {
157                 ret = xmalloc(sizeof(*ret));
158                 hashmap_entry_init(&ret->hash, key.hash.hash);
159                 ret->orig = xstrdup(orig);
160                 ret->orig_len = *len;
161                 ret->anon = generate(orig, len);
162                 ret->anon_len = *len;
163                 hashmap_put(map, ret);
164         }
165
166         *len = ret->anon_len;
167         return ret->anon;
168 }
169
170 /*
171  * We anonymize each component of a path individually,
172  * so that paths a/b and a/c will share a common root.
173  * The paths are cached via anonymize_mem so that repeated
174  * lookups for "a" will yield the same value.
175  */
176 static void anonymize_path(struct strbuf *out, const char *path,
177                            struct hashmap *map,
178                            void *(*generate)(const void *, size_t *))
179 {
180         while (*path) {
181                 const char *end_of_component = strchrnul(path, '/');
182                 size_t len = end_of_component - path;
183                 const char *c = anonymize_mem(map, generate, path, &len);
184                 strbuf_add(out, c, len);
185                 path = end_of_component;
186                 if (*path)
187                         strbuf_addch(out, *path++);
188         }
189 }
190
191 static inline void *mark_to_ptr(uint32_t mark)
192 {
193         return (void *)(uintptr_t)mark;
194 }
195
196 static inline uint32_t ptr_to_mark(void * mark)
197 {
198         return (uint32_t)(uintptr_t)mark;
199 }
200
201 static inline void mark_object(struct object *object, uint32_t mark)
202 {
203         add_decoration(&idnums, object, mark_to_ptr(mark));
204 }
205
206 static inline void mark_next_object(struct object *object)
207 {
208         mark_object(object, ++last_idnum);
209 }
210
211 static int get_object_mark(struct object *object)
212 {
213         void *decoration = lookup_decoration(&idnums, object);
214         if (!decoration)
215                 return 0;
216         return ptr_to_mark(decoration);
217 }
218
219 static struct commit *rewrite_commit(struct commit *p)
220 {
221         for (;;) {
222                 if (p->parents && p->parents->next)
223                         break;
224                 if (p->object.flags & UNINTERESTING)
225                         break;
226                 if (!(p->object.flags & TREESAME))
227                         break;
228                 if (!p->parents)
229                         return NULL;
230                 p = p->parents->item;
231         }
232         return p;
233 }
234
235 static void show_progress(void)
236 {
237         static int counter = 0;
238         if (!progress)
239                 return;
240         if ((++counter % progress) == 0)
241                 printf("progress %d objects\n", counter);
242 }
243
244 /*
245  * Ideally we would want some transformation of the blob data here
246  * that is unreversible, but would still be the same size and have
247  * the same data relationship to other blobs (so that we get the same
248  * delta and packing behavior as the original). But the first and last
249  * requirements there are probably mutually exclusive, so let's take
250  * the easy way out for now, and just generate arbitrary content.
251  *
252  * There's no need to cache this result with anonymize_mem, since
253  * we already handle blob content caching with marks.
254  */
255 static char *anonymize_blob(unsigned long *size)
256 {
257         static int counter;
258         struct strbuf out = STRBUF_INIT;
259         strbuf_addf(&out, "anonymous blob %d", counter++);
260         *size = out.len;
261         return strbuf_detach(&out, NULL);
262 }
263
264 static void export_blob(const struct object_id *oid)
265 {
266         unsigned long size;
267         enum object_type type;
268         char *buf;
269         struct object *object;
270         int eaten;
271
272         if (no_data)
273                 return;
274
275         if (is_null_oid(oid))
276                 return;
277
278         object = lookup_object(the_repository, oid);
279         if (object && object->flags & SHOWN)
280                 return;
281
282         if (anonymize) {
283                 buf = anonymize_blob(&size);
284                 object = (struct object *)lookup_blob(the_repository, oid);
285                 eaten = 0;
286         } else {
287                 buf = read_object_file(oid, &type, &size);
288                 if (!buf)
289                         die("could not read blob %s", oid_to_hex(oid));
290                 if (check_object_signature(oid, buf, size, type_name(type)) < 0)
291                         die("oid mismatch in blob %s", oid_to_hex(oid));
292                 object = parse_object_buffer(the_repository, oid, type,
293                                              size, buf, &eaten);
294         }
295
296         if (!object)
297                 die("Could not read blob %s", oid_to_hex(oid));
298
299         mark_next_object(object);
300
301         printf("blob\nmark :%"PRIu32"\n", last_idnum);
302         if (show_original_ids)
303                 printf("original-oid %s\n", oid_to_hex(oid));
304         printf("data %"PRIuMAX"\n", (uintmax_t)size);
305         if (size && fwrite(buf, size, 1, stdout) != 1)
306                 die_errno("could not write blob '%s'", oid_to_hex(oid));
307         printf("\n");
308
309         show_progress();
310
311         object->flags |= SHOWN;
312         if (!eaten)
313                 free(buf);
314 }
315
316 static int depth_first(const void *a_, const void *b_)
317 {
318         const struct diff_filepair *a = *((const struct diff_filepair **)a_);
319         const struct diff_filepair *b = *((const struct diff_filepair **)b_);
320         const char *name_a, *name_b;
321         int len_a, len_b, len;
322         int cmp;
323
324         name_a = a->one ? a->one->path : a->two->path;
325         name_b = b->one ? b->one->path : b->two->path;
326
327         len_a = strlen(name_a);
328         len_b = strlen(name_b);
329         len = (len_a < len_b) ? len_a : len_b;
330
331         /* strcmp will sort 'd' before 'd/e', we want 'd/e' before 'd' */
332         cmp = memcmp(name_a, name_b, len);
333         if (cmp)
334                 return cmp;
335         cmp = len_b - len_a;
336         if (cmp)
337                 return cmp;
338         /*
339          * Move 'R'ename entries last so that all references of the file
340          * appear in the output before it is renamed (e.g., when a file
341          * was copied and renamed in the same commit).
342          */
343         return (a->status == 'R') - (b->status == 'R');
344 }
345
346 static void print_path_1(const char *path)
347 {
348         int need_quote = quote_c_style(path, NULL, NULL, 0);
349         if (need_quote)
350                 quote_c_style(path, NULL, stdout, 0);
351         else if (strchr(path, ' '))
352                 printf("\"%s\"", path);
353         else
354                 printf("%s", path);
355 }
356
357 static void *anonymize_path_component(const void *path, size_t *len)
358 {
359         static int counter;
360         struct strbuf out = STRBUF_INIT;
361         strbuf_addf(&out, "path%d", counter++);
362         return strbuf_detach(&out, len);
363 }
364
365 static void print_path(const char *path)
366 {
367         if (!anonymize)
368                 print_path_1(path);
369         else {
370                 static struct hashmap paths;
371                 static struct strbuf anon = STRBUF_INIT;
372
373                 anonymize_path(&anon, path, &paths, anonymize_path_component);
374                 print_path_1(anon.buf);
375                 strbuf_reset(&anon);
376         }
377 }
378
379 static void *generate_fake_oid(const void *old, size_t *len)
380 {
381         static uint32_t counter = 1; /* avoid null oid */
382         const unsigned hashsz = the_hash_algo->rawsz;
383         unsigned char *out = xcalloc(hashsz, 1);
384         put_be32(out + hashsz - 4, counter++);
385         return out;
386 }
387
388 static const struct object_id *anonymize_oid(const struct object_id *oid)
389 {
390         static struct hashmap objs;
391         size_t len = the_hash_algo->rawsz;
392         return anonymize_mem(&objs, generate_fake_oid, oid, &len);
393 }
394
395 static void show_filemodify(struct diff_queue_struct *q,
396                             struct diff_options *options, void *data)
397 {
398         int i;
399         struct string_list *changed = data;
400
401         /*
402          * Handle files below a directory first, in case they are all deleted
403          * and the directory changes to a file or symlink.
404          */
405         QSORT(q->queue, q->nr, depth_first);
406
407         for (i = 0; i < q->nr; i++) {
408                 struct diff_filespec *ospec = q->queue[i]->one;
409                 struct diff_filespec *spec = q->queue[i]->two;
410
411                 switch (q->queue[i]->status) {
412                 case DIFF_STATUS_DELETED:
413                         printf("D ");
414                         print_path(spec->path);
415                         string_list_insert(changed, spec->path);
416                         putchar('\n');
417                         break;
418
419                 case DIFF_STATUS_COPIED:
420                 case DIFF_STATUS_RENAMED:
421                         /*
422                          * If a change in the file corresponding to ospec->path
423                          * has been observed, we cannot trust its contents
424                          * because the diff is calculated based on the prior
425                          * contents, not the current contents.  So, declare a
426                          * copy or rename only if there was no change observed.
427                          */
428                         if (!string_list_has_string(changed, ospec->path)) {
429                                 printf("%c ", q->queue[i]->status);
430                                 print_path(ospec->path);
431                                 putchar(' ');
432                                 print_path(spec->path);
433                                 string_list_insert(changed, spec->path);
434                                 putchar('\n');
435
436                                 if (oideq(&ospec->oid, &spec->oid) &&
437                                     ospec->mode == spec->mode)
438                                         break;
439                         }
440                         /* fallthrough */
441
442                 case DIFF_STATUS_TYPE_CHANGED:
443                 case DIFF_STATUS_MODIFIED:
444                 case DIFF_STATUS_ADDED:
445                         /*
446                          * Links refer to objects in another repositories;
447                          * output the SHA-1 verbatim.
448                          */
449                         if (no_data || S_ISGITLINK(spec->mode))
450                                 printf("M %06o %s ", spec->mode,
451                                        oid_to_hex(anonymize ?
452                                                   anonymize_oid(&spec->oid) :
453                                                   &spec->oid));
454                         else {
455                                 struct object *object = lookup_object(the_repository,
456                                                                       &spec->oid);
457                                 printf("M %06o :%d ", spec->mode,
458                                        get_object_mark(object));
459                         }
460                         print_path(spec->path);
461                         string_list_insert(changed, spec->path);
462                         putchar('\n');
463                         break;
464
465                 default:
466                         die("Unexpected comparison status '%c' for %s, %s",
467                                 q->queue[i]->status,
468                                 ospec->path ? ospec->path : "none",
469                                 spec->path ? spec->path : "none");
470                 }
471         }
472 }
473
474 static const char *find_encoding(const char *begin, const char *end)
475 {
476         const char *needle = "\nencoding ";
477         char *bol, *eol;
478
479         bol = memmem(begin, end ? end - begin : strlen(begin),
480                      needle, strlen(needle));
481         if (!bol)
482                 return NULL;
483         bol += strlen(needle);
484         eol = strchrnul(bol, '\n');
485         *eol = '\0';
486         return bol;
487 }
488
489 static void *anonymize_ref_component(const void *old, size_t *len)
490 {
491         static int counter;
492         struct strbuf out = STRBUF_INIT;
493         strbuf_addf(&out, "ref%d", counter++);
494         return strbuf_detach(&out, len);
495 }
496
497 static const char *anonymize_refname(const char *refname)
498 {
499         /*
500          * If any of these prefixes is found, we will leave it intact
501          * so that tags remain tags and so forth.
502          */
503         static const char *prefixes[] = {
504                 "refs/heads/",
505                 "refs/tags/",
506                 "refs/remotes/",
507                 "refs/"
508         };
509         static struct hashmap refs;
510         static struct strbuf anon = STRBUF_INIT;
511         int i;
512
513         /*
514          * We also leave "master" as a special case, since it does not reveal
515          * anything interesting.
516          */
517         if (!strcmp(refname, "refs/heads/master"))
518                 return refname;
519
520         strbuf_reset(&anon);
521         for (i = 0; i < ARRAY_SIZE(prefixes); i++) {
522                 if (skip_prefix(refname, prefixes[i], &refname)) {
523                         strbuf_addstr(&anon, prefixes[i]);
524                         break;
525                 }
526         }
527
528         anonymize_path(&anon, refname, &refs, anonymize_ref_component);
529         return anon.buf;
530 }
531
532 /*
533  * We do not even bother to cache commit messages, as they are unlikely
534  * to be repeated verbatim, and it is not that interesting when they are.
535  */
536 static char *anonymize_commit_message(const char *old)
537 {
538         static int counter;
539         return xstrfmt("subject %d\n\nbody\n", counter++);
540 }
541
542 static struct hashmap idents;
543 static void *anonymize_ident(const void *old, size_t *len)
544 {
545         static int counter;
546         struct strbuf out = STRBUF_INIT;
547         strbuf_addf(&out, "User %d <user%d@example.com>", counter, counter);
548         counter++;
549         return strbuf_detach(&out, len);
550 }
551
552 /*
553  * Our strategy here is to anonymize the names and email addresses,
554  * but keep timestamps intact, as they influence things like traversal
555  * order (and by themselves should not be too revealing).
556  */
557 static void anonymize_ident_line(const char **beg, const char **end)
558 {
559         static struct strbuf buffers[] = { STRBUF_INIT, STRBUF_INIT };
560         static unsigned which_buffer;
561
562         struct strbuf *out;
563         struct ident_split split;
564         const char *end_of_header;
565
566         out = &buffers[which_buffer++];
567         which_buffer %= ARRAY_SIZE(buffers);
568         strbuf_reset(out);
569
570         /* skip "committer", "author", "tagger", etc */
571         end_of_header = strchr(*beg, ' ');
572         if (!end_of_header)
573                 BUG("malformed line fed to anonymize_ident_line: %.*s",
574                     (int)(*end - *beg), *beg);
575         end_of_header++;
576         strbuf_add(out, *beg, end_of_header - *beg);
577
578         if (!split_ident_line(&split, end_of_header, *end - end_of_header) &&
579             split.date_begin) {
580                 const char *ident;
581                 size_t len;
582
583                 len = split.mail_end - split.name_begin;
584                 ident = anonymize_mem(&idents, anonymize_ident,
585                                       split.name_begin, &len);
586                 strbuf_add(out, ident, len);
587                 strbuf_addch(out, ' ');
588                 strbuf_add(out, split.date_begin, split.tz_end - split.date_begin);
589         } else {
590                 strbuf_addstr(out, "Malformed Ident <malformed@example.com> 0 -0000");
591         }
592
593         *beg = out->buf;
594         *end = out->buf + out->len;
595 }
596
597 static void handle_commit(struct commit *commit, struct rev_info *rev,
598                           struct string_list *paths_of_changed_objects)
599 {
600         int saved_output_format = rev->diffopt.output_format;
601         const char *commit_buffer;
602         const char *author, *author_end, *committer, *committer_end;
603         const char *encoding, *message;
604         char *reencoded = NULL;
605         struct commit_list *p;
606         const char *refname;
607         int i;
608
609         rev->diffopt.output_format = DIFF_FORMAT_CALLBACK;
610
611         parse_commit_or_die(commit);
612         commit_buffer = get_commit_buffer(commit, NULL);
613         author = strstr(commit_buffer, "\nauthor ");
614         if (!author)
615                 die("could not find author in commit %s",
616                     oid_to_hex(&commit->object.oid));
617         author++;
618         author_end = strchrnul(author, '\n');
619         committer = strstr(author_end, "\ncommitter ");
620         if (!committer)
621                 die("could not find committer in commit %s",
622                     oid_to_hex(&commit->object.oid));
623         committer++;
624         committer_end = strchrnul(committer, '\n');
625         message = strstr(committer_end, "\n\n");
626         encoding = find_encoding(committer_end, message);
627         if (message)
628                 message += 2;
629
630         if (commit->parents &&
631             (get_object_mark(&commit->parents->item->object) != 0 ||
632              reference_excluded_commits) &&
633             !full_tree) {
634                 parse_commit_or_die(commit->parents->item);
635                 diff_tree_oid(get_commit_tree_oid(commit->parents->item),
636                               get_commit_tree_oid(commit), "", &rev->diffopt);
637         }
638         else
639                 diff_root_tree_oid(get_commit_tree_oid(commit),
640                                    "", &rev->diffopt);
641
642         /* Export the referenced blobs, and remember the marks. */
643         for (i = 0; i < diff_queued_diff.nr; i++)
644                 if (!S_ISGITLINK(diff_queued_diff.queue[i]->two->mode))
645                         export_blob(&diff_queued_diff.queue[i]->two->oid);
646
647         refname = *revision_sources_at(&revision_sources, commit);
648         /*
649          * FIXME: string_list_remove() below for each ref is overall
650          * O(N^2).  Compared to a history walk and diffing trees, this is
651          * just lost in the noise in practice.  However, theoretically a
652          * repo may have enough refs for this to become slow.
653          */
654         string_list_remove(&extra_refs, refname, 0);
655         if (anonymize) {
656                 refname = anonymize_refname(refname);
657                 anonymize_ident_line(&committer, &committer_end);
658                 anonymize_ident_line(&author, &author_end);
659         }
660
661         mark_next_object(&commit->object);
662         if (anonymize) {
663                 reencoded = anonymize_commit_message(message);
664         } else if (encoding) {
665                 switch(reencode_mode) {
666                 case REENCODE_YES:
667                         reencoded = reencode_string(message, "UTF-8", encoding);
668                         break;
669                 case REENCODE_NO:
670                         break;
671                 case REENCODE_ABORT:
672                         die("Encountered commit-specific encoding %s in commit "
673                             "%s; use --reencode=[yes|no] to handle it",
674                             encoding, oid_to_hex(&commit->object.oid));
675                 }
676         }
677         if (!commit->parents)
678                 printf("reset %s\n", refname);
679         printf("commit %s\nmark :%"PRIu32"\n", refname, last_idnum);
680         if (show_original_ids)
681                 printf("original-oid %s\n", oid_to_hex(&commit->object.oid));
682         printf("%.*s\n%.*s\n",
683                (int)(author_end - author), author,
684                (int)(committer_end - committer), committer);
685         if (!reencoded && encoding)
686                 printf("encoding %s\n", encoding);
687         printf("data %u\n%s",
688                (unsigned)(reencoded
689                           ? strlen(reencoded) : message
690                           ? strlen(message) : 0),
691                reencoded ? reencoded : message ? message : "");
692         free(reencoded);
693         unuse_commit_buffer(commit, commit_buffer);
694
695         for (i = 0, p = commit->parents; p; p = p->next) {
696                 struct object *obj = &p->item->object;
697                 int mark = get_object_mark(obj);
698
699                 if (!mark && !reference_excluded_commits)
700                         continue;
701                 if (i == 0)
702                         printf("from ");
703                 else
704                         printf("merge ");
705                 if (mark)
706                         printf(":%d\n", mark);
707                 else
708                         printf("%s\n", oid_to_hex(anonymize ?
709                                                   anonymize_oid(&obj->oid) :
710                                                   &obj->oid));
711                 i++;
712         }
713
714         if (full_tree)
715                 printf("deleteall\n");
716         log_tree_diff_flush(rev);
717         string_list_clear(paths_of_changed_objects, 0);
718         rev->diffopt.output_format = saved_output_format;
719
720         printf("\n");
721
722         show_progress();
723 }
724
725 static void *anonymize_tag(const void *old, size_t *len)
726 {
727         static int counter;
728         struct strbuf out = STRBUF_INIT;
729         strbuf_addf(&out, "tag message %d", counter++);
730         return strbuf_detach(&out, len);
731 }
732
733 static void handle_tail(struct object_array *commits, struct rev_info *revs,
734                         struct string_list *paths_of_changed_objects)
735 {
736         struct commit *commit;
737         while (commits->nr) {
738                 commit = (struct commit *)object_array_pop(commits);
739                 if (has_unshown_parent(commit)) {
740                         /* Queue again, to be handled later */
741                         add_object_array(&commit->object, NULL, commits);
742                         return;
743                 }
744                 handle_commit(commit, revs, paths_of_changed_objects);
745         }
746 }
747
748 static void handle_tag(const char *name, struct tag *tag)
749 {
750         unsigned long size;
751         enum object_type type;
752         char *buf;
753         const char *tagger, *tagger_end, *message;
754         size_t message_size = 0;
755         struct object *tagged;
756         int tagged_mark;
757         struct commit *p;
758
759         /* Trees have no identifier in fast-export output, thus we have no way
760          * to output tags of trees, tags of tags of trees, etc.  Simply omit
761          * such tags.
762          */
763         tagged = tag->tagged;
764         while (tagged->type == OBJ_TAG) {
765                 tagged = ((struct tag *)tagged)->tagged;
766         }
767         if (tagged->type == OBJ_TREE) {
768                 warning("Omitting tag %s,\nsince tags of trees (or tags of tags of trees, etc.) are not supported.",
769                         oid_to_hex(&tag->object.oid));
770                 return;
771         }
772
773         buf = read_object_file(&tag->object.oid, &type, &size);
774         if (!buf)
775                 die("could not read tag %s", oid_to_hex(&tag->object.oid));
776         message = memmem(buf, size, "\n\n", 2);
777         if (message) {
778                 message += 2;
779                 message_size = strlen(message);
780         }
781         tagger = memmem(buf, message ? message - buf : size, "\ntagger ", 8);
782         if (!tagger) {
783                 if (fake_missing_tagger)
784                         tagger = "tagger Unspecified Tagger "
785                                 "<unspecified-tagger> 0 +0000";
786                 else
787                         tagger = "";
788                 tagger_end = tagger + strlen(tagger);
789         } else {
790                 tagger++;
791                 tagger_end = strchrnul(tagger, '\n');
792                 if (anonymize)
793                         anonymize_ident_line(&tagger, &tagger_end);
794         }
795
796         if (anonymize) {
797                 name = anonymize_refname(name);
798                 if (message) {
799                         static struct hashmap tags;
800                         message = anonymize_mem(&tags, anonymize_tag,
801                                                 message, &message_size);
802                 }
803         }
804
805         /* handle signed tags */
806         if (message) {
807                 const char *signature = strstr(message,
808                                                "\n-----BEGIN PGP SIGNATURE-----\n");
809                 if (signature)
810                         switch(signed_tag_mode) {
811                         case SIGNED_TAG_ABORT:
812                                 die("encountered signed tag %s; use "
813                                     "--signed-tags=<mode> to handle it",
814                                     oid_to_hex(&tag->object.oid));
815                         case WARN:
816                                 warning("exporting signed tag %s",
817                                         oid_to_hex(&tag->object.oid));
818                                 /* fallthru */
819                         case VERBATIM:
820                                 break;
821                         case WARN_STRIP:
822                                 warning("stripping signature from tag %s",
823                                         oid_to_hex(&tag->object.oid));
824                                 /* fallthru */
825                         case STRIP:
826                                 message_size = signature + 1 - message;
827                                 break;
828                         }
829         }
830
831         /* handle tag->tagged having been filtered out due to paths specified */
832         tagged = tag->tagged;
833         tagged_mark = get_object_mark(tagged);
834         if (!tagged_mark) {
835                 switch(tag_of_filtered_mode) {
836                 case TAG_FILTERING_ABORT:
837                         die("tag %s tags unexported object; use "
838                             "--tag-of-filtered-object=<mode> to handle it",
839                             oid_to_hex(&tag->object.oid));
840                 case DROP:
841                         /* Ignore this tag altogether */
842                         free(buf);
843                         return;
844                 case REWRITE:
845                         if (tagged->type != OBJ_COMMIT) {
846                                 die("tag %s tags unexported %s!",
847                                     oid_to_hex(&tag->object.oid),
848                                     type_name(tagged->type));
849                         }
850                         p = rewrite_commit((struct commit *)tagged);
851                         if (!p) {
852                                 printf("reset %s\nfrom %s\n\n",
853                                        name, oid_to_hex(&null_oid));
854                                 free(buf);
855                                 return;
856                         }
857                         tagged_mark = get_object_mark(&p->object);
858                 }
859         }
860
861         if (starts_with(name, "refs/tags/"))
862                 name += 10;
863         printf("tag %s\nfrom :%d\n", name, tagged_mark);
864         if (show_original_ids)
865                 printf("original-oid %s\n", oid_to_hex(&tag->object.oid));
866         printf("%.*s%sdata %d\n%.*s\n",
867                (int)(tagger_end - tagger), tagger,
868                tagger == tagger_end ? "" : "\n",
869                (int)message_size, (int)message_size, message ? message : "");
870         free(buf);
871 }
872
873 static struct commit *get_commit(struct rev_cmdline_entry *e, char *full_name)
874 {
875         switch (e->item->type) {
876         case OBJ_COMMIT:
877                 return (struct commit *)e->item;
878         case OBJ_TAG: {
879                 struct tag *tag = (struct tag *)e->item;
880
881                 /* handle nested tags */
882                 while (tag && tag->object.type == OBJ_TAG) {
883                         parse_object(the_repository, &tag->object.oid);
884                         string_list_append(&tag_refs, full_name)->util = tag;
885                         tag = (struct tag *)tag->tagged;
886                 }
887                 if (!tag)
888                         die("Tag %s points nowhere?", e->name);
889                 return (struct commit *)tag;
890                 break;
891         }
892         default:
893                 return NULL;
894         }
895 }
896
897 static void get_tags_and_duplicates(struct rev_cmdline_info *info)
898 {
899         int i;
900
901         for (i = 0; i < info->nr; i++) {
902                 struct rev_cmdline_entry *e = info->rev + i;
903                 struct object_id oid;
904                 struct commit *commit;
905                 char *full_name;
906
907                 if (e->flags & UNINTERESTING)
908                         continue;
909
910                 if (dwim_ref(e->name, strlen(e->name), &oid, &full_name) != 1)
911                         continue;
912
913                 if (refspecs.nr) {
914                         char *private;
915                         private = apply_refspecs(&refspecs, full_name);
916                         if (private) {
917                                 free(full_name);
918                                 full_name = private;
919                         }
920                 }
921
922                 commit = get_commit(e, full_name);
923                 if (!commit) {
924                         warning("%s: Unexpected object of type %s, skipping.",
925                                 e->name,
926                                 type_name(e->item->type));
927                         continue;
928                 }
929
930                 switch(commit->object.type) {
931                 case OBJ_COMMIT:
932                         break;
933                 case OBJ_BLOB:
934                         export_blob(&commit->object.oid);
935                         continue;
936                 default: /* OBJ_TAG (nested tags) is already handled */
937                         warning("Tag points to object of unexpected type %s, skipping.",
938                                 type_name(commit->object.type));
939                         continue;
940                 }
941
942                 /*
943                  * Make sure this ref gets properly updated eventually, whether
944                  * through a commit or manually at the end.
945                  */
946                 if (e->item->type != OBJ_TAG)
947                         string_list_append(&extra_refs, full_name)->util = commit;
948
949                 if (!*revision_sources_at(&revision_sources, commit))
950                         *revision_sources_at(&revision_sources, commit) = full_name;
951         }
952
953         string_list_sort(&extra_refs);
954         string_list_remove_duplicates(&extra_refs, 0);
955 }
956
957 static void handle_tags_and_duplicates(struct string_list *extras)
958 {
959         struct commit *commit;
960         int i;
961
962         for (i = extras->nr - 1; i >= 0; i--) {
963                 const char *name = extras->items[i].string;
964                 struct object *object = extras->items[i].util;
965                 int mark;
966
967                 switch (object->type) {
968                 case OBJ_TAG:
969                         handle_tag(name, (struct tag *)object);
970                         break;
971                 case OBJ_COMMIT:
972                         if (anonymize)
973                                 name = anonymize_refname(name);
974                         /* create refs pointing to already seen commits */
975                         commit = rewrite_commit((struct commit *)object);
976                         if (!commit) {
977                                 /*
978                                  * Neither this object nor any of its
979                                  * ancestors touch any relevant paths, so
980                                  * it has been filtered to nothing.  Delete
981                                  * it.
982                                  */
983                                 printf("reset %s\nfrom %s\n\n",
984                                        name, oid_to_hex(&null_oid));
985                                 continue;
986                         }
987
988                         mark = get_object_mark(&commit->object);
989                         if (!mark) {
990                                 /*
991                                  * Getting here means we have a commit which
992                                  * was excluded by a negative refspec (e.g.
993                                  * fast-export ^master master).  If we are
994                                  * referencing excluded commits, set the ref
995                                  * to the exact commit.  Otherwise, the user
996                                  * wants the branch exported but every commit
997                                  * in its history to be deleted, which basically
998                                  * just means deletion of the ref.
999                                  */
1000                                 if (!reference_excluded_commits) {
1001                                         /* delete the ref */
1002                                         printf("reset %s\nfrom %s\n\n",
1003                                                name, oid_to_hex(&null_oid));
1004                                         continue;
1005                                 }
1006                                 /* set ref to commit using oid, not mark */
1007                                 printf("reset %s\nfrom %s\n\n", name,
1008                                        oid_to_hex(&commit->object.oid));
1009                                 continue;
1010                         }
1011
1012                         printf("reset %s\nfrom :%d\n\n", name, mark
1013                                );
1014                         show_progress();
1015                         break;
1016                 }
1017         }
1018 }
1019
1020 static void export_marks(char *file)
1021 {
1022         unsigned int i;
1023         uint32_t mark;
1024         struct decoration_entry *deco = idnums.entries;
1025         FILE *f;
1026         int e = 0;
1027
1028         f = fopen_for_writing(file);
1029         if (!f)
1030                 die_errno("Unable to open marks file %s for writing.", file);
1031
1032         for (i = 0; i < idnums.size; i++) {
1033                 if (deco->base && deco->base->type == 1) {
1034                         mark = ptr_to_mark(deco->decoration);
1035                         if (fprintf(f, ":%"PRIu32" %s\n", mark,
1036                                 oid_to_hex(&deco->base->oid)) < 0) {
1037                             e = 1;
1038                             break;
1039                         }
1040                 }
1041                 deco++;
1042         }
1043
1044         e |= ferror(f);
1045         e |= fclose(f);
1046         if (e)
1047                 error("Unable to write marks file %s.", file);
1048 }
1049
1050 static void import_marks(char *input_file)
1051 {
1052         char line[512];
1053         FILE *f = xfopen(input_file, "r");
1054
1055         while (fgets(line, sizeof(line), f)) {
1056                 uint32_t mark;
1057                 char *line_end, *mark_end;
1058                 struct object_id oid;
1059                 struct object *object;
1060                 struct commit *commit;
1061                 enum object_type type;
1062
1063                 line_end = strchr(line, '\n');
1064                 if (line[0] != ':' || !line_end)
1065                         die("corrupt mark line: %s", line);
1066                 *line_end = '\0';
1067
1068                 mark = strtoumax(line + 1, &mark_end, 10);
1069                 if (!mark || mark_end == line + 1
1070                         || *mark_end != ' ' || get_oid_hex(mark_end + 1, &oid))
1071                         die("corrupt mark line: %s", line);
1072
1073                 if (last_idnum < mark)
1074                         last_idnum = mark;
1075
1076                 type = oid_object_info(the_repository, &oid, NULL);
1077                 if (type < 0)
1078                         die("object not found: %s", oid_to_hex(&oid));
1079
1080                 if (type != OBJ_COMMIT)
1081                         /* only commits */
1082                         continue;
1083
1084                 commit = lookup_commit(the_repository, &oid);
1085                 if (!commit)
1086                         die("not a commit? can't happen: %s", oid_to_hex(&oid));
1087
1088                 object = &commit->object;
1089
1090                 if (object->flags & SHOWN)
1091                         error("Object %s already has a mark", oid_to_hex(&oid));
1092
1093                 mark_object(object, mark);
1094
1095                 object->flags |= SHOWN;
1096         }
1097         fclose(f);
1098 }
1099
1100 static void handle_deletes(void)
1101 {
1102         int i;
1103         for (i = 0; i < refspecs.nr; i++) {
1104                 struct refspec_item *refspec = &refspecs.items[i];
1105                 if (*refspec->src)
1106                         continue;
1107
1108                 printf("reset %s\nfrom %s\n\n",
1109                                 refspec->dst, oid_to_hex(&null_oid));
1110         }
1111 }
1112
1113 int cmd_fast_export(int argc, const char **argv, const char *prefix)
1114 {
1115         struct rev_info revs;
1116         struct object_array commits = OBJECT_ARRAY_INIT;
1117         struct commit *commit;
1118         char *export_filename = NULL, *import_filename = NULL;
1119         uint32_t lastimportid;
1120         struct string_list refspecs_list = STRING_LIST_INIT_NODUP;
1121         struct string_list paths_of_changed_objects = STRING_LIST_INIT_DUP;
1122         struct option options[] = {
1123                 OPT_INTEGER(0, "progress", &progress,
1124                             N_("show progress after <n> objects")),
1125                 OPT_CALLBACK(0, "signed-tags", &signed_tag_mode, N_("mode"),
1126                              N_("select handling of signed tags"),
1127                              parse_opt_signed_tag_mode),
1128                 OPT_CALLBACK(0, "tag-of-filtered-object", &tag_of_filtered_mode, N_("mode"),
1129                              N_("select handling of tags that tag filtered objects"),
1130                              parse_opt_tag_of_filtered_mode),
1131                 OPT_CALLBACK(0, "reencode", &reencode_mode, N_("mode"),
1132                              N_("select handling of commit messages in an alternate encoding"),
1133                              parse_opt_reencode_mode),
1134                 OPT_STRING(0, "export-marks", &export_filename, N_("file"),
1135                              N_("Dump marks to this file")),
1136                 OPT_STRING(0, "import-marks", &import_filename, N_("file"),
1137                              N_("Import marks from this file")),
1138                 OPT_BOOL(0, "fake-missing-tagger", &fake_missing_tagger,
1139                          N_("Fake a tagger when tags lack one")),
1140                 OPT_BOOL(0, "full-tree", &full_tree,
1141                          N_("Output full tree for each commit")),
1142                 OPT_BOOL(0, "use-done-feature", &use_done_feature,
1143                              N_("Use the done feature to terminate the stream")),
1144                 OPT_BOOL(0, "no-data", &no_data, N_("Skip output of blob data")),
1145                 OPT_STRING_LIST(0, "refspec", &refspecs_list, N_("refspec"),
1146                              N_("Apply refspec to exported refs")),
1147                 OPT_BOOL(0, "anonymize", &anonymize, N_("anonymize output")),
1148                 OPT_BOOL(0, "reference-excluded-parents",
1149                          &reference_excluded_commits, N_("Reference parents which are not in fast-export stream by object id")),
1150                 OPT_BOOL(0, "show-original-ids", &show_original_ids,
1151                             N_("Show original object ids of blobs/commits")),
1152
1153                 OPT_END()
1154         };
1155
1156         if (argc == 1)
1157                 usage_with_options (fast_export_usage, options);
1158
1159         /* we handle encodings */
1160         git_config(git_default_config, NULL);
1161
1162         repo_init_revisions(the_repository, &revs, prefix);
1163         init_revision_sources(&revision_sources);
1164         revs.topo_order = 1;
1165         revs.sources = &revision_sources;
1166         revs.rewrite_parents = 1;
1167         argc = parse_options(argc, argv, prefix, options, fast_export_usage,
1168                         PARSE_OPT_KEEP_ARGV0 | PARSE_OPT_KEEP_UNKNOWN);
1169         argc = setup_revisions(argc, argv, &revs, NULL);
1170         if (argc > 1)
1171                 usage_with_options (fast_export_usage, options);
1172
1173         if (refspecs_list.nr) {
1174                 int i;
1175
1176                 for (i = 0; i < refspecs_list.nr; i++)
1177                         refspec_append(&refspecs, refspecs_list.items[i].string);
1178
1179                 string_list_clear(&refspecs_list, 1);
1180         }
1181
1182         if (use_done_feature)
1183                 printf("feature done\n");
1184
1185         if (import_filename)
1186                 import_marks(import_filename);
1187         lastimportid = last_idnum;
1188
1189         if (import_filename && revs.prune_data.nr)
1190                 full_tree = 1;
1191
1192         get_tags_and_duplicates(&revs.cmdline);
1193
1194         if (prepare_revision_walk(&revs))
1195                 die("revision walk setup failed");
1196         revs.diffopt.format_callback = show_filemodify;
1197         revs.diffopt.format_callback_data = &paths_of_changed_objects;
1198         revs.diffopt.flags.recursive = 1;
1199         while ((commit = get_revision(&revs))) {
1200                 if (has_unshown_parent(commit)) {
1201                         add_object_array(&commit->object, NULL, &commits);
1202                 }
1203                 else {
1204                         handle_commit(commit, &revs, &paths_of_changed_objects);
1205                         handle_tail(&commits, &revs, &paths_of_changed_objects);
1206                 }
1207         }
1208
1209         handle_tags_and_duplicates(&extra_refs);
1210         handle_tags_and_duplicates(&tag_refs);
1211         handle_deletes();
1212
1213         if (export_filename && lastimportid != last_idnum)
1214                 export_marks(export_filename);
1215
1216         if (use_done_feature)
1217                 printf("done\n");
1218
1219         refspec_clear(&refspecs);
1220
1221         return 0;
1222 }