[PATCH] delta check
[git/git.git] / delta.c
1 #include "object.h"
2 #include "blob.h"
3 #include "tree.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "delta.h"
7 #include "cache.h"
8 #include <string.h>
9
10 /* the delta object definition (it can alias any other object) */
11 struct delta {
12 union {
13 struct object object;
14 struct blob blob;
15 struct tree tree;
16 struct commit commit;
17 struct tag tag;
18 } u;
19 };
20
21 struct delta *lookup_delta(unsigned char *sha1)
22 {
23 struct object *obj = lookup_object(sha1);
24 if (!obj) {
25 struct delta *ret = xmalloc(sizeof(struct delta));
26 memset(ret, 0, sizeof(struct delta));
27 created_object(sha1, &ret->u.object);
28 return ret;
29 }
30 return (struct delta *) obj;
31 }
32
33 int parse_delta_buffer(struct delta *item, void *buffer, unsigned long size)
34 {
35 struct object *reference;
36 struct object_list *p;
37
38 if (item->u.object.delta)
39 return 0;
40 item->u.object.delta = 1;
41 if (size <= 20)
42 return -1;
43 reference = lookup_object(buffer);
44 if (!reference) {
45 struct delta *ref = xmalloc(sizeof(struct delta));
46 memset(ref, 0, sizeof(struct delta));
47 created_object(buffer, &ref->u.object);
48 reference = &ref->u.object;
49 }
50
51 p = xmalloc(sizeof(*p));
52 p->item = &item->u.object;
53 p->next = reference->attached_deltas;
54 reference->attached_deltas = p;
55 return 0;
56 }
57
58 int process_deltas(void *src, unsigned long src_size, const char *src_type,
59 struct object_list *delta_list)
60 {
61 int deepest = 0;
62 do {
63 struct object *obj = delta_list->item;
64 static char type[10];
65 void *map, *delta, *buf;
66 unsigned long map_size, delta_size, buf_size;
67 map = map_sha1_file(obj->sha1, &map_size);
68 if (!map)
69 continue;
70 delta = unpack_sha1_file(map, map_size, type, &delta_size);
71 munmap(map, map_size);
72 if (!delta)
73 continue;
74 if (strcmp(type, "delta") || delta_size <= 20) {
75 free(delta);
76 continue;
77 }
78 buf = patch_delta(src, src_size,
79 delta+20, delta_size-20,
80 &buf_size);
81 free(delta);
82 if (!buf)
83 continue;
84 if (check_sha1_signature(obj->sha1, buf, buf_size, src_type) < 0)
85 printf("sha1 mismatch for delta %s\n", sha1_to_hex(obj->sha1));
86 if (obj->type && obj->type != src_type) {
87 error("got %s when expecting %s for delta %s",
88 src_type, obj->type, sha1_to_hex(obj->sha1));
89 free(buf);
90 continue;
91 }
92 obj->type = src_type;
93 if (src_type == blob_type) {
94 parse_blob_buffer((struct blob *)obj, buf, buf_size);
95 } else if (src_type == tree_type) {
96 parse_tree_buffer((struct tree *)obj, buf, buf_size);
97 } else if (src_type == commit_type) {
98 parse_commit_buffer((struct commit *)obj, buf, buf_size);
99 } else if (src_type == tag_type) {
100 parse_tag_buffer((struct tag *)obj, buf, buf_size);
101 } else {
102 error("unknown object type %s", src_type);
103 free(buf);
104 continue;
105 }
106 if (obj->attached_deltas) {
107 int depth = process_deltas(buf, buf_size, src_type,
108 obj->attached_deltas);
109 if (deepest < depth)
110 deepest = depth;
111 }
112 free(buf);
113 } while ((delta_list = delta_list->next));
114 return deepest + 1;
115 }