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#include "cache.h"
static int recursive = 0;
static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base);
static void update_tree_entry(void **bufp, unsigned long *sizep)
{
void *buf = *bufp;
unsigned long size = *sizep;
int len = strlen(buf) + 1 + 20;
if (size < len)
die("corrupt tree file");
*bufp = buf + len;
*sizep = size - len;
}
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)
die("corrupt tree file");
*pathp = path+1;
return sha1;
}
static char *malloc_base(const char *base, const char *path, int pathlen)
{
int baselen = strlen(base);
char *newbase = malloc(baselen + pathlen + 2);
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, path, pathlen);
memcpy(newbase + baselen + pathlen, "/", 2);
return newbase;
}
static void show_file(const char *prefix, void *tree, unsigned long size, const char *base);
/* A whole sub-tree went away or appeared */
static void show_tree(const char *prefix, void *tree, unsigned long size, const char *base)
{
while (size) {
show_file(prefix, tree, size, base);
update_tree_entry(&tree, &size);
}
}
/* A file entry went away or appeared */
static void show_file(const char *prefix, void *tree, unsigned long size, const char *base)
{
unsigned mode;
const char *path;
const unsigned char *sha1 = extract(tree, size, &path, &mode);
if (recursive && S_ISDIR(mode)) {
char type[20];
unsigned long size;
char *newbase = malloc_base(base, path, strlen(path));
void *tree;
tree = read_sha1_file(sha1, type, &size);
if (!tree || strcmp(type, "tree"))
die("corrupt tree sha %s", sha1_to_hex(sha1));
show_tree(prefix, tree, size, newbase);
free(tree);
free(newbase);
return;
}
printf("%s%o\t%s\t%s\t%s%s%c", prefix, mode,
S_ISDIR(mode) ? "tree" : "blob",
sha1_to_hex(sha1), base, path, 0);
}
static int compare_tree_entry(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
{
unsigned mode1, mode2;
const char *path1, *path2;
const unsigned char *sha1, *sha2;
int cmp, pathlen1, pathlen2;
char old_sha1_hex[50];
sha1 = extract(tree1, size1, &path1, &mode1);
sha2 = extract(tree2, size2, &path2, &mode2);
pathlen1 = strlen(path1);
pathlen2 = strlen(path2);
cmp = cache_name_compare(path1, pathlen1, path2, pathlen2);
if (cmp < 0) {
show_file("-", tree1, size1, base);
return -1;
}
if (cmp > 0) {
show_file("+", tree2, size2, base);
return 1;
}
if (!memcmp(sha1, sha2, 20) && mode1 == mode2)
return 0;
/*
* If the filemode has changed to/from a directory from/to a regular
* file, we need to consider it a remove and an add.
*/
if (S_ISDIR(mode1) != S_ISDIR(mode2)) {
show_file("-", tree1, size1, base);
show_file("+", tree2, size2, base);
return 0;
}
if (recursive && S_ISDIR(mode1)) {
int retval;
char *newbase = malloc_base(base, path1, pathlen1);
retval = diff_tree_sha1(sha1, sha2, newbase);
free(newbase);
return retval;
}
strcpy(old_sha1_hex, sha1_to_hex(sha1));
printf("*%o->%o\t%s\t%s->%s\t%s%s%c", mode1, mode2,
S_ISDIR(mode1) ? "tree" : "blob",
old_sha1_hex, sha1_to_hex(sha2), base, path1, 0);
return 0;
}
static int diff_tree(void *tree1, unsigned long size1, void *tree2, unsigned long size2, const char *base)
{
while (size1 | size2) {
if (!size1) {
show_file("+", tree2, size2, base);
update_tree_entry(&tree2, &size2);
continue;
}
if (!size2) {
show_file("-", tree1, size1, base);
update_tree_entry(&tree1, &size1);
continue;
}
switch (compare_tree_entry(tree1, size1, tree2, size2, base)) {
case -1:
update_tree_entry(&tree1, &size1);
continue;
case 0:
update_tree_entry(&tree1, &size1);
/* Fallthrough */
case 1:
update_tree_entry(&tree2, &size2);
continue;
}
die("diff-tree: internal error");
}
return 0;
}
static int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base)
{
void *tree1, *tree2;
unsigned long size1, size2;
char type[20];
int retval;
tree1 = read_sha1_file(old, type, &size1);
if (!tree1 || strcmp(type, "tree"))
die("unable to read source tree (%s)", sha1_to_hex(old));
tree2 = read_sha1_file(new, type, &size2);
if (!tree2 || strcmp(type, "tree"))
die("unable to read destination tree (%s)", sha1_to_hex(new));
retval = diff_tree(tree1, size1, tree2, size2, base);
free(tree1);
free(tree2);
return retval;
}
int main(int argc, char **argv)
{
unsigned char old[20], new[20];
while (argc > 3) {
char *arg = argv[1];
argv++;
argc--;
if (!strcmp(arg, "-r")) {
recursive = 1;
continue;
}
usage("diff-tree [-r] <tree sha1> <tree sha1>");
}
if (argc != 3 || get_sha1_hex(argv[1], old) || get_sha1_hex(argv[2], new))
usage("diff-tree <tree sha1> <tree sha1>");
return diff_tree_sha1(old, new, "");
}
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