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Christian Couder68095572009-01-23 10:06:53 +01001#include "cache.h"
2#include "sha1-lookup.h"
3#include "refs.h"
Stephen Boydc2e86ad2011-03-22 00:51:05 -07004#include "commit.h"
Christian Couder68095572009-01-23 10:06:53 +01005
Michael Haggertyce375862014-02-21 17:32:03 +01006/*
7 * An array of replacements. The array is kept sorted by the original
8 * sha1.
9 */
Christian Couder68095572009-01-23 10:06:53 +010010static struct replace_object {
Michael Haggertyce375862014-02-21 17:32:03 +010011 unsigned char original[20];
12 unsigned char replacement[20];
Christian Couder68095572009-01-23 10:06:53 +010013} **replace_object;
14
15static int replace_object_alloc, replace_object_nr;
16
17static const unsigned char *replace_sha1_access(size_t index, void *table)
18{
19 struct replace_object **replace = table;
Michael Haggertyce375862014-02-21 17:32:03 +010020 return replace[index]->original;
Christian Couder68095572009-01-23 10:06:53 +010021}
22
23static int replace_object_pos(const unsigned char *sha1)
24{
25 return sha1_pos(sha1, replace_object, replace_object_nr,
26 replace_sha1_access);
27}
28
29static int register_replace_object(struct replace_object *replace,
30 int ignore_dups)
31{
Michael Haggertyce375862014-02-21 17:32:03 +010032 int pos = replace_object_pos(replace->original);
Christian Couder68095572009-01-23 10:06:53 +010033
34 if (0 <= pos) {
35 if (ignore_dups)
36 free(replace);
37 else {
38 free(replace_object[pos]);
39 replace_object[pos] = replace;
40 }
41 return 1;
42 }
43 pos = -pos - 1;
Dmitry S. Dolzhenko72004b42014-03-04 02:31:56 +040044 ALLOC_GROW(replace_object, replace_object_nr + 1, replace_object_alloc);
45 replace_object_nr++;
Christian Couder68095572009-01-23 10:06:53 +010046 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;
53}
54
55static int register_replace_ref(const char *refname,
56 const unsigned char *sha1,
57 int flag, void *cb_data)
58{
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));
63
Michael Haggertyce375862014-02-21 17:32:03 +010064 if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->original)) {
Christian Couder68095572009-01-23 10:06:53 +010065 free(repl_obj);
66 warning("bad replace ref name: %s", refname);
67 return 0;
68 }
69
70 /* Copy sha1 from the read ref */
Michael Haggertyce375862014-02-21 17:32:03 +010071 hashcpy(repl_obj->replacement, sha1);
Christian Couder68095572009-01-23 10:06:53 +010072
73 /* Register new object */
74 if (register_replace_object(repl_obj, 1))
75 die("duplicate replace ref: %s", refname);
76
77 return 0;
78}
79
80static void prepare_replace_object(void)
81{
82 static int replace_object_prepared;
83
84 if (replace_object_prepared)
85 return;
86
87 for_each_replace_ref(register_replace_ref, NULL);
88 replace_object_prepared = 1;
Junio C Hamanoe1111ce2011-05-15 12:54:53 -070089 if (!replace_object_nr)
Michael Haggertyafc711b2014-02-18 12:24:55 +010090 check_replace_refs = 0;
Christian Couder68095572009-01-23 10:06:53 +010091}
92
93/* We allow "recursive" replacement. Only within reason, though */
94#define MAXREPLACEDEPTH 5
95
Michael Haggerty1f91e792014-02-28 17:29:16 +010096/*
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.
102 */
Junio C Hamanoe1111ce2011-05-15 12:54:53 -0700103const unsigned char *do_lookup_replace_object(const unsigned char *sha1)
Christian Couder68095572009-01-23 10:06:53 +0100104{
105 int pos, depth = MAXREPLACEDEPTH;
106 const unsigned char *cur = sha1;
107
Christian Couder68095572009-01-23 10:06:53 +0100108 prepare_replace_object();
109
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));
115
116 pos = replace_object_pos(cur);
117 if (0 <= pos)
Michael Haggertyce375862014-02-21 17:32:03 +0100118 cur = replace_object[pos]->replacement;
Christian Couder68095572009-01-23 10:06:53 +0100119 } while (0 <= pos);
120
121 return cur;
122}