Merge branch 'jk/tag-sort'
[git.git] / replace_object.c
blob0ab2dc137487259d50b69258e967792aa6c43619
1 #include "cache.h"
2 #include "sha1-lookup.h"
3 #include "refs.h"
4 #include "commit.h"
6 /*
7 * An array of replacements. The array is kept sorted by the original
8 * sha1.
9 */
10 static struct replace_object {
11 unsigned char original[20];
12 unsigned char replacement[20];
13 } **replace_object;
15 static int replace_object_alloc, replace_object_nr;
17 static const unsigned char *replace_sha1_access(size_t index, void *table)
19 struct replace_object **replace = table;
20 return replace[index]->original;
23 static int replace_object_pos(const unsigned char *sha1)
25 return sha1_pos(sha1, replace_object, replace_object_nr,
26 replace_sha1_access);
29 static int register_replace_object(struct replace_object *replace,
30 int ignore_dups)
32 int pos = replace_object_pos(replace->original);
34 if (0 <= pos) {
35 if (ignore_dups)
36 free(replace);
37 else {
38 free(replace_object[pos]);
39 replace_object[pos] = replace;
41 return 1;
43 pos = -pos - 1;
44 ALLOC_GROW(replace_object, replace_object_nr + 1, replace_object_alloc);
45 replace_object_nr++;
46 if (pos < replace_object_nr)
47 memmove(replace_object + pos + 1,
48 replace_object + pos,
49 (replace_object_nr - pos - 1) *
50 sizeof(*replace_object));
51 replace_object[pos] = replace;
52 return 0;
55 static int register_replace_ref(const char *refname,
56 const unsigned char *sha1,
57 int flag, void *cb_data)
59 /* Get sha1 from refname */
60 const char *slash = strrchr(refname, '/');
61 const char *hash = slash ? slash + 1 : refname;
62 struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
64 if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->original)) {
65 free(repl_obj);
66 warning("bad replace ref name: %s", refname);
67 return 0;
70 /* Copy sha1 from the read ref */
71 hashcpy(repl_obj->replacement, sha1);
73 /* Register new object */
74 if (register_replace_object(repl_obj, 1))
75 die("duplicate replace ref: %s", refname);
77 return 0;
80 static void prepare_replace_object(void)
82 static int replace_object_prepared;
84 if (replace_object_prepared)
85 return;
87 for_each_replace_ref(register_replace_ref, NULL);
88 replace_object_prepared = 1;
89 if (!replace_object_nr)
90 check_replace_refs = 0;
93 /* We allow "recursive" replacement. Only within reason, though */
94 #define MAXREPLACEDEPTH 5
97 * If a replacement for object sha1 has been set up, return the
98 * replacement object's name (replaced recursively, if necessary).
99 * The return value is either sha1 or a pointer to a
100 * permanently-allocated value. This function always respects replace
101 * references, regardless of the value of check_replace_refs.
103 const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
105 int pos, depth = MAXREPLACEDEPTH;
106 const unsigned char *cur = sha1;
108 prepare_replace_object();
110 /* Try to recursively replace the object */
111 do {
112 if (--depth < 0)
113 die("replace depth too high for object %s",
114 sha1_to_hex(sha1));
116 pos = replace_object_pos(cur);
117 if (0 <= pos)
118 cur = replace_object[pos]->replacement;
119 } while (0 <= pos);
121 return cur;