Merge branch 'sg/t7406-chain-fix'
[git] / replace-object.c
1 #include "cache.h"
2 #include "oidmap.h"
3 #include "object-store.h"
4 #include "replace-object.h"
5 #include "refs.h"
6 #include "repository.h"
7 #include "commit.h"
8
9 static int register_replace_ref(const char *refname,
10                                 const struct object_id *oid,
11                                 int flag, void *cb_data)
12 {
13         /* Get sha1 from refname */
14         const char *slash = strrchr(refname, '/');
15         const char *hash = slash ? slash + 1 : refname;
16         struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
17
18         if (get_oid_hex(hash, &repl_obj->original.oid)) {
19                 free(repl_obj);
20                 warning("bad replace ref name: %s", refname);
21                 return 0;
22         }
23
24         /* Copy sha1 from the read ref */
25         oidcpy(&repl_obj->replacement, oid);
26
27         /* Register new object */
28         if (oidmap_put(the_repository->objects->replace_map, repl_obj))
29                 die("duplicate replace ref: %s", refname);
30
31         return 0;
32 }
33
34 static void prepare_replace_object(struct repository *r)
35 {
36         if (r->objects->replace_map)
37                 return;
38
39         r->objects->replace_map =
40                 xmalloc(sizeof(*r->objects->replace_map));
41         oidmap_init(r->objects->replace_map, 0);
42
43         for_each_replace_ref(r, register_replace_ref, NULL);
44 }
45
46 /* We allow "recursive" replacement. Only within reason, though */
47 #define MAXREPLACEDEPTH 5
48
49 /*
50  * If a replacement for object oid has been set up, return the
51  * replacement object's name (replaced recursively, if necessary).
52  * The return value is either oid or a pointer to a
53  * permanently-allocated value.  This function always respects replace
54  * references, regardless of the value of check_replace_refs.
55  */
56 const struct object_id *do_lookup_replace_object(struct repository *r,
57                                                  const struct object_id *oid)
58 {
59         int depth = MAXREPLACEDEPTH;
60         const struct object_id *cur = oid;
61
62         prepare_replace_object(r);
63
64         /* Try to recursively replace the object */
65         while (depth-- > 0) {
66                 struct replace_object *repl_obj =
67                         oidmap_get(r->objects->replace_map, cur);
68                 if (!repl_obj)
69                         return cur;
70                 cur = &repl_obj->replacement;
71         }
72         die("replace depth too high for object %s", oid_to_hex(oid));
73 }