]> git.ipfire.org Git - thirdparty/git.git/blob - symlinks.c
Optimize symlink/directory detection
[thirdparty/git.git] / symlinks.c
1 #include "cache.h"
2
3 struct pathname {
4 int len;
5 char path[PATH_MAX];
6 };
7
8 /* Return matching pathname prefix length, or zero if not matching */
9 static inline int match_pathname(int len, const char *name, struct pathname *match)
10 {
11 int match_len = match->len;
12 return (len > match_len &&
13 name[match_len] == '/' &&
14 !memcmp(name, match->path, match_len)) ? match_len : 0;
15 }
16
17 static inline void set_pathname(int len, const char *name, struct pathname *match)
18 {
19 if (len < PATH_MAX) {
20 match->len = len;
21 memcpy(match->path, name, len);
22 match->path[len] = 0;
23 }
24 }
25
26 int has_symlink_leading_path(int len, const char *name)
27 {
28 static struct pathname link, nonlink;
29 char path[PATH_MAX];
30 struct stat st;
31 char *sp;
32 int known_dir;
33
34 /*
35 * See if the last known symlink cache matches.
36 */
37 if (match_pathname(len, name, &link))
38 return 1;
39
40 /*
41 * Get rid of the last known directory part
42 */
43 known_dir = match_pathname(len, name, &nonlink);
44
45 while ((sp = strchr(name + known_dir + 1, '/')) != NULL) {
46 int thislen = sp - name ;
47 memcpy(path, name, thislen);
48 path[thislen] = 0;
49
50 if (lstat(path, &st))
51 return 0;
52 if (S_ISDIR(st.st_mode)) {
53 set_pathname(thislen, path, &nonlink);
54 known_dir = thislen;
55 continue;
56 }
57 if (S_ISLNK(st.st_mode)) {
58 set_pathname(thislen, path, &link);
59 return 1;
60 }
61 break;
62 }
63 return 0;
64 }