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delta.c
114 lines (108 loc) · 2.88 KB
/
delta.c
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#include "object.h"
#include "blob.h"
#include "tree.h"
#include "commit.h"
#include "tag.h"
#include "delta.h"
#include "cache.h"
/* the delta object definition (it can alias any other object) */
struct delta {
union {
struct object object;
struct blob blob;
struct tree tree;
struct commit commit;
struct tag tag;
} u;
};
struct delta *lookup_delta(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj) {
struct delta *ret = xmalloc(sizeof(struct delta));
memset(ret, 0, sizeof(struct delta));
created_object(sha1, &ret->u.object);
return ret;
}
return (struct delta *) obj;
}
int parse_delta_buffer(struct delta *item, void *buffer, unsigned long size)
{
struct object *reference;
struct object_list *p;
if (item->u.object.delta)
return 0;
item->u.object.delta = 1;
if (size <= 20)
return -1;
reference = lookup_object(buffer);
if (!reference) {
struct delta *ref = xmalloc(sizeof(struct delta));
memset(ref, 0, sizeof(struct delta));
created_object(buffer, &ref->u.object);
reference = &ref->u.object;
}
p = xmalloc(sizeof(*p));
p->item = &item->u.object;
p->next = reference->attached_deltas;
reference->attached_deltas = p;
return 0;
}
int process_deltas(void *src, unsigned long src_size, const char *src_type,
struct object_list *delta_list)
{
int deepest = 0;
do {
struct object *obj = delta_list->item;
static char type[10];
void *map, *delta, *buf;
unsigned long map_size, delta_size, buf_size;
map = map_sha1_file(obj->sha1, &map_size);
if (!map)
continue;
delta = unpack_sha1_file(map, map_size, type, &delta_size);
munmap(map, map_size);
if (!delta)
continue;
if (strcmp(type, "delta") || delta_size <= 20) {
free(delta);
continue;
}
buf = patch_delta(src, src_size,
delta+20, delta_size-20,
&buf_size);
free(delta);
if (!buf)
continue;
if (check_sha1_signature(obj->sha1, buf, buf_size, src_type) < 0)
printf("sha1 mismatch for delta %s\n", sha1_to_hex(obj->sha1));
if (obj->type && obj->type != src_type) {
error("got %s when expecting %s for delta %s",
src_type, obj->type, sha1_to_hex(obj->sha1));
free(buf);
continue;
}
obj->type = src_type;
if (src_type == blob_type) {
parse_blob_buffer((struct blob *)obj, buf, buf_size);
} else if (src_type == tree_type) {
parse_tree_buffer((struct tree *)obj, buf, buf_size);
} else if (src_type == commit_type) {
parse_commit_buffer((struct commit *)obj, buf, buf_size);
} else if (src_type == tag_type) {
parse_tag_buffer((struct tag *)obj, buf, buf_size);
} else {
error("unknown object type %s", src_type);
free(buf);
continue;
}
if (obj->attached_deltas) {
int depth = process_deltas(buf, buf_size, src_type,
obj->attached_deltas);
if (deepest < depth)
deepest = depth;
}
free(buf);
} while ((delta_list = delta_list->next));
return deepest + 1;
}