replace_object: use oidmap
[git/git.git] / replace_object.c
1 #include "cache.h"
2 #include "oidmap.h"
3 #include "refs.h"
4 #include "commit.h"
5
6 struct replace_object {
7 struct oidmap_entry original;
8 struct object_id replacement;
9 };
10
11 static struct oidmap replace_map = OIDMAP_INIT;
12
13 static int register_replace_ref(const char *refname,
14 const struct object_id *oid,
15 int flag, void *cb_data)
16 {
17 /* Get sha1 from refname */
18 const char *slash = strrchr(refname, '/');
19 const char *hash = slash ? slash + 1 : refname;
20 struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
21
22 if (get_oid_hex(hash, &repl_obj->original.oid)) {
23 free(repl_obj);
24 warning("bad replace ref name: %s", refname);
25 return 0;
26 }
27
28 /* Copy sha1 from the read ref */
29 oidcpy(&repl_obj->replacement, oid);
30
31 /* Register new object */
32 if (oidmap_put(&replace_map, repl_obj))
33 die("duplicate replace ref: %s", refname);
34
35 return 0;
36 }
37
38 static void prepare_replace_object(void)
39 {
40 static int replace_object_prepared;
41
42 if (replace_object_prepared)
43 return;
44
45 for_each_replace_ref(register_replace_ref, NULL);
46 replace_object_prepared = 1;
47 if (!replace_map.map.tablesize)
48 check_replace_refs = 0;
49 }
50
51 /* We allow "recursive" replacement. Only within reason, though */
52 #define MAXREPLACEDEPTH 5
53
54 /*
55 * If a replacement for object oid has been set up, return the
56 * replacement object's name (replaced recursively, if necessary).
57 * The return value is either oid or a pointer to a
58 * permanently-allocated value. This function always respects replace
59 * references, regardless of the value of check_replace_refs.
60 */
61 const struct object_id *do_lookup_replace_object(const struct object_id *oid)
62 {
63 int depth = MAXREPLACEDEPTH;
64 const struct object_id *cur = oid;
65
66 prepare_replace_object();
67
68 /* Try to recursively replace the object */
69 while (depth-- > 0) {
70 struct replace_object *repl_obj = oidmap_get(&replace_map, cur);
71 if (!repl_obj)
72 return cur;
73 cur = &repl_obj->replacement;
74 }
75 die("replace depth too high for object %s", oid_to_hex(oid));
76 }