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#include "cache.h"
struct tree_entry;
static struct tree_entry *update_tree_entry(void **bufp, unsigned long *sizep)
{
void *buf = *bufp;
unsigned long size = *sizep;
int len = strlen(buf) + 1 + 20;
if (size < len)
usage("corrupt tree file");
*bufp = buf + len;
*sizep = size - len;
return buf;
}
static const unsigned char *extract(void *tree, unsigned long size, const char **pathp, unsigned int *modep)
{
int len = strlen(tree)+1;
const unsigned char *sha1 = tree + len;
const char *path = strchr(tree, ' ');
if (!path || size < len + 20 || sscanf(tree, "%o", modep) != 1)
usage("corrupt tree file");
*pathp = path+1;
return sha1;
}
static void show_file(const char *prefix, void *tree, unsigned long size)
{
unsigned mode;
const char *path;
const unsigned char *sha1 = extract(tree, size, &path, &mode);
printf("%s%o %s %s%c", prefix, mode, sha1_to_hex(sha1), path, 0);
}
static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2)
{
unsigned mode1, mode2;
const char *path1, *path2;
const unsigned char *sha1, *sha2;
int cmp;
sha1 = extract(tree1, size1, &path1, &mode1);
sha2 = extract(tree2, size2, &path2, &mode2);
cmp = cache_name_compare(path1, strlen(path1), path2, strlen(path2));
if (cmp < 0) {
show_file("-", tree1, size1);
return -1;
}
if (cmp > 0) {
show_file("+", tree2, size2);
return 1;
}
if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
return 0;
show_file("<", tree1, size1);
show_file(">", tree2, size2);
return 0;
}
static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2)
{
while (size1 | size2) {
if (!size1) {
show_file("+", tree2, size2);
update_tree_entry(&tree2, &size2);
continue;
}
if (!size2) {
show_file("-", tree1, size1);
update_tree_entry(&tree1, &size1);
continue;
}
switch (compare_tree_entry(tree1, size1, tree2, size2)) {
case -1:
update_tree_entry(&tree1, &size1);
continue;
case 0:
update_tree_entry(&tree1, &size1);
/* Fallthrough */
case 1:
update_tree_entry(&tree2, &size2);
continue;
}
usage("diff-tree: internal error");
}
return 0;
}
int main(int argc, char **argv)
{
unsigned char old[20], new[20];
void *tree1, *tree2;
unsigned long size1, size2;
char type[20];
if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
usage("diff-tree <tree sha1> <tree sha1>");
tree1 = read_sha1_file(old, type, &size1);
if (!tree1 || strcmp(type, "tree"))
usage("unable to read source tree");
tree2 = read_sha1_file(new, type, &size2);
if (!tree2 || strcmp(type, "tree"))
usage("unable to read destination tree");
return diff_tree(tree1, size1, tree2, size2);
}
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