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git/tree-diff.c
David Rientjes a89fccd281 Do not use memcmp(sha1_1, sha1_2, 20) with hardcoded length.
Introduces global inline:

	hashcmp(const unsigned char *sha1, const unsigned char *sha2)

Uses memcmp for comparison and returns the result based on the length of
the hash name (a future runtime decision).

Acked-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-08-17 14:23:53 -07:00

250 lines
5.7 KiB
C

/*
* Helper functions for tree diff generation
*/
#include "cache.h"
#include "diff.h"
#include "tree.h"
static char *malloc_base(const char *base, const char *path, int pathlen)
{
int baselen = strlen(base);
char *newbase = xmalloc(baselen + pathlen + 2);
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, path, pathlen);
memcpy(newbase + baselen + pathlen, "/", 2);
return newbase;
}
static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
const char *base);
static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
{
unsigned mode1, mode2;
const char *path1, *path2;
const unsigned char *sha1, *sha2;
int cmp, pathlen1, pathlen2;
sha1 = tree_entry_extract(t1, &path1, &mode1);
sha2 = tree_entry_extract(t2, &path2, &mode2);
pathlen1 = strlen(path1);
pathlen2 = strlen(path2);
cmp = base_name_compare(path1, pathlen1, mode1, path2, pathlen2, mode2);
if (cmp < 0) {
show_entry(opt, "-", t1, base);
return -1;
}
if (cmp > 0) {
show_entry(opt, "+", t2, base);
return 1;
}
if (!opt->find_copies_harder && !hashcmp(sha1, sha2) && 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_entry(opt, "-", t1, base);
show_entry(opt, "+", t2, base);
return 0;
}
if (opt->recursive && S_ISDIR(mode1)) {
int retval;
char *newbase = malloc_base(base, path1, pathlen1);
if (opt->tree_in_recursive)
opt->change(opt, mode1, mode2,
sha1, sha2, base, path1);
retval = diff_tree_sha1(sha1, sha2, newbase, opt);
free(newbase);
return retval;
}
opt->change(opt, mode1, mode2, sha1, sha2, base, path1);
return 0;
}
static int interesting(struct tree_desc *desc, const char *base, struct diff_options *opt)
{
const char *path;
unsigned mode;
int i;
int baselen, pathlen;
if (!opt->nr_paths)
return 1;
(void)tree_entry_extract(desc, &path, &mode);
pathlen = strlen(path);
baselen = strlen(base);
for (i=0; i < opt->nr_paths; i++) {
const char *match = opt->paths[i];
int matchlen = opt->pathlens[i];
if (baselen >= matchlen) {
/* If it doesn't match, move along... */
if (strncmp(base, match, matchlen))
continue;
/* The base is a subdirectory of a path which was specified. */
return 1;
}
/* Does the base match? */
if (strncmp(base, match, baselen))
continue;
match += baselen;
matchlen -= baselen;
if (pathlen > matchlen)
continue;
if (matchlen > pathlen) {
if (match[pathlen] != '/')
continue;
if (!S_ISDIR(mode))
continue;
}
if (strncmp(path, match, pathlen))
continue;
return 1;
}
return 0; /* No matches */
}
/* A whole sub-tree went away or appeared */
static void show_tree(struct diff_options *opt, const char *prefix, struct tree_desc *desc, const char *base)
{
while (desc->size) {
if (interesting(desc, base, opt))
show_entry(opt, prefix, desc, base);
update_tree_entry(desc);
}
}
/* A file entry went away or appeared */
static void show_entry(struct diff_options *opt, const char *prefix, struct tree_desc *desc,
const char *base)
{
unsigned mode;
const char *path;
const unsigned char *sha1 = tree_entry_extract(desc, &path, &mode);
if (opt->recursive && S_ISDIR(mode)) {
char type[20];
char *newbase = malloc_base(base, path, strlen(path));
struct tree_desc inner;
void *tree;
tree = read_sha1_file(sha1, type, &inner.size);
if (!tree || strcmp(type, tree_type))
die("corrupt tree sha %s", sha1_to_hex(sha1));
inner.buf = tree;
show_tree(opt, prefix, &inner, newbase);
free(tree);
free(newbase);
} else {
opt->add_remove(opt, prefix[0], mode, sha1, base, path);
}
}
int diff_tree(struct tree_desc *t1, struct tree_desc *t2, const char *base, struct diff_options *opt)
{
while (t1->size | t2->size) {
if (opt->nr_paths && t1->size && !interesting(t1, base, opt)) {
update_tree_entry(t1);
continue;
}
if (opt->nr_paths && t2->size && !interesting(t2, base, opt)) {
update_tree_entry(t2);
continue;
}
if (!t1->size) {
show_entry(opt, "+", t2, base);
update_tree_entry(t2);
continue;
}
if (!t2->size) {
show_entry(opt, "-", t1, base);
update_tree_entry(t1);
continue;
}
switch (compare_tree_entry(t1, t2, base, opt)) {
case -1:
update_tree_entry(t1);
continue;
case 0:
update_tree_entry(t1);
/* Fallthrough */
case 1:
update_tree_entry(t2);
continue;
}
die("git-diff-tree: internal error");
}
return 0;
}
int diff_tree_sha1(const unsigned char *old, const unsigned char *new, const char *base, struct diff_options *opt)
{
void *tree1, *tree2;
struct tree_desc t1, t2;
int retval;
tree1 = read_object_with_reference(old, tree_type, &t1.size, NULL);
if (!tree1)
die("unable to read source tree (%s)", sha1_to_hex(old));
tree2 = read_object_with_reference(new, tree_type, &t2.size, NULL);
if (!tree2)
die("unable to read destination tree (%s)", sha1_to_hex(new));
t1.buf = tree1;
t2.buf = tree2;
retval = diff_tree(&t1, &t2, base, opt);
free(tree1);
free(tree2);
return retval;
}
static int count_paths(const char **paths)
{
int i = 0;
while (*paths++)
i++;
return i;
}
void diff_tree_release_paths(struct diff_options *opt)
{
free(opt->pathlens);
}
void diff_tree_setup_paths(const char **p, struct diff_options *opt)
{
opt->nr_paths = 0;
opt->pathlens = NULL;
opt->paths = NULL;
if (p) {
int i;
opt->paths = p;
opt->nr_paths = count_paths(p);
if (opt->nr_paths == 0) {
opt->pathlens = NULL;
return;
}
opt->pathlens = xmalloc(opt->nr_paths * sizeof(int));
for (i=0; i < opt->nr_paths; i++)
opt->pathlens[i] = strlen(p[i]);
}
}