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#include "cache.h"
struct tree_entry {
unsigned mode;
unsigned char *sha1;
char *path;
struct tree_entry *next;
};
static struct tree_entry *read_tree(unsigned char *sha1)
{
char type[20];
unsigned long size;
void *buf = read_sha1_file(sha1, type, &size);
struct tree_entry *ret = NULL, **tp = &ret;
if (!buf || strcmp(type, "tree"))
die("unable to read 'tree' object %s", sha1_to_hex(sha1));
while (size) {
int len = strlen(buf)+1;
struct tree_entry * entry = malloc(sizeof(struct tree_entry));
if (size < len + 20 || sscanf(buf, "%o", &entry->mode) != 1)
die("corrupt 'tree' object %s", sha1_to_hex(sha1));
entry->path = strchr(buf, ' ')+1;
entry->sha1 = buf + len;
entry->next = NULL;
*tp = entry;
tp = &entry->next;
len += 20;
buf += len;
size -= len;
}
return ret;
}
static void show(const struct tree_entry *a, const char *path)
{
printf("select %o %s %s%c", a->mode, sha1_to_hex(a->sha1), path, 0);
}
static void merge(const struct tree_entry *a, const struct tree_entry *b, const struct tree_entry *c, const char *path)
{
char hex_a[60], hex_b[60], hex_c[60];
strcpy(hex_a, sha1_to_hex(a->sha1));
strcpy(hex_b, sha1_to_hex(b->sha1));
strcpy(hex_c, sha1_to_hex(c->sha1));
printf("merge %o->%o,%o %s->%s,%s %s%c",
a->mode, b->mode, c->mode,
hex_a, hex_b, hex_c, path, 0);
}
static int same(const struct tree_entry *a, const struct tree_entry *b)
{
return a->mode == b->mode && !memcmp(a->sha1, b->sha1, 20);
}
static void merge_entry(const struct tree_entry *src, const struct tree_entry *dst1, const struct tree_entry *dst2)
{
static unsigned char nullsha1[20];
static const struct tree_entry none = { 0, nullsha1, "", NULL };
const char *path = NULL;
const struct tree_entry *a, *b, *c;
a = &none;
b = &none;
c = &none;
if (src) { a = src; path = src->path; }
if (dst1) { b = dst1; path = dst1->path; }
if (dst2) { c = dst2; path = dst2->path; }
if (same(b, c)) {
show(b, path);
return;
}
if (same(a, b)) {
show(c, path);
return;
}
if (same(a, c)) {
show(b, path);
return;
}
merge(a, b, c, path);
}
/* For two entries, select the smaller one, clear the bigger one */
static void smaller(struct tree_entry **ap, struct tree_entry **bp)
{
struct tree_entry *a = *ap, *b = *bp;
if (a && b) {
int cmp = cache_name_compare(a->path, strlen(a->path), b->path, strlen(b->path));
if (cmp) {
if (cmp < 0)
*bp = NULL;
else
*ap = NULL;
}
}
}
static void merge_tree(struct tree_entry *src, struct tree_entry *dst1, struct tree_entry *dst2)
{
while (src || dst1 || dst2) {
struct tree_entry *a, *b, *c;
a = src;
b = dst1;
c = dst2;
smaller(&a,&b);
smaller(&a,&c);
smaller(&b,&c);
if (a) src = a->next;
if (b) dst1 = b->next;
if (c) dst2 = c->next;
merge_entry(a,b,c);
}
}
int main(int argc, char **argv)
{
unsigned char src[20], dst1[20], dst2[20];
if (argc != 4 ||
get_sha1_hex(argv[1], src) ||
get_sha1_hex(argv[2], dst1) ||
get_sha1_hex(argv[3], dst2))
usage("merge-tree <src> <dst1> <dst2>");
merge_tree(read_tree(src), read_tree(dst1), read_tree(dst2));
return 0;
}
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