Make git-pack-redundant non-horribly slow on large sets of packs

diff --git a/setup.c b/setup.c
index 258da176150081749a2ca2faeebc316911f0fba1..c487d7eb9de70c651ef06a6bfd4a7571337fad84 100644 (file)
--- a/setup.c
+++ b/setup.c
@@ -1,8 +1,8 @@
 #include "cache.h"
 
-char *prefix_path(const char *prefix, int len, char *path)
+const char *prefix_path(const char *prefix, int len, const char *path)
 {
-       char *orig = path;
+       const char *orig = path;
        for (;;) {
                char c;
                if (*path != '.')
@@ -47,10 +47,10 @@ char *prefix_path(const char *prefix, int len, char *path)
        return path;
 }
 
-const char **get_pathspec(const char *prefix, char **pathspec)
+const char **get_pathspec(const char *prefix, const char **pathspec)
 {
-       char *entry = *pathspec;
-       char **p;
+       const char *entry = *pathspec;
+       const char **p;
        int prefixlen;
 
        if (!prefix && !entry)
@@ -76,18 +76,20 @@ const char **get_pathspec(const char *prefix, char **pathspec)
  * Test it it looks like we're at the top
  * level git directory. We want to see a
  *
- *  - a HEAD symlink and a refs/ directory under ".git"
  *  - either a .git/objects/ directory _or_ the proper
  *    GIT_OBJECT_DIRECTORY environment variable
+ *  - a refs/ directory under ".git"
+ *  - either a HEAD symlink or a HEAD file that is formatted as
+ *    a proper "ref:".
  */
 static int is_toplevel_directory(void)
 {
-       struct stat st;
-
-       return  !lstat(".git/HEAD", &st) &&
-               S_ISLNK(st.st_mode) &&
-               !access(".git/refs/", X_OK) &&
-               (gitenv(DB_ENVIRONMENT) || !access(".git/objects/", X_OK));
+       if (access(".git/refs/", X_OK) ||
+           access(getenv(DB_ENVIRONMENT) ?
+                  getenv(DB_ENVIRONMENT) : ".git/objects/", X_OK) ||
+           validate_symref(".git/HEAD"))
+               return 0;
+       return 1;
 }
 
 const char *setup_git_directory(void)
@@ -99,7 +101,7 @@ const char *setup_git_directory(void)
         * If GIT_DIR is set explicitly, we're not going
         * to do any discovery
         */
-       if (gitenv(GIT_DIR_ENVIRONMENT))
+       if (getenv(GIT_DIR_ENVIRONMENT))
                return NULL;
 
        if (!getcwd(cwd, sizeof(cwd)) || cwd[0] != '/')