Add threaded versions of functions in symlinks.c.

check_leading_path() and has_dirs_only_path() both always use the default
cache, which could be a caveat for adding parallelism (which is a concern
and even a GSoC proposal).

Reimplement these two in terms of new threaded_check_leading_path() and
threaded_has_dirs_only_path() that take their own copy of the cache.

Signed-off-by: Jared Hance <jaredhance@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -950,7 +950,9 @@ struct cache_def {
 extern int has_symlink_leading_path(const char *name, int len);
 extern int threaded_has_symlink_leading_path(struct cache_def *, const char *, int);
 extern int check_leading_path(const char *name, int len);
+extern int threaded_check_leading_path(struct cache_def *cache, const char *name, int len);
 extern int has_dirs_only_path(const char *name, int len, int prefix_len);
+extern int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len);
 extern void schedule_dir_for_removal(const char *name, int len);
 extern void remove_scheduled_dirs(void);
 

symlinks.c

@@ -219,7 +219,20 @@ int has_symlink_leading_path(const char *name, int len)
  */
 int check_leading_path(const char *name, int len)
 {
-	struct cache_def *cache = &default_cache;	/* FIXME */
+    return threaded_check_leading_path(&default_cache, name, len);
+}
+
+/*
+ * Return zero if path 'name' has a leading symlink component or
+ * if some leading path component does not exists.
+ *
+ * Return -1 if leading path exists and is a directory.
+ *
+ * Return path length if leading path exists and is neither a
+ * directory nor a symlink.
+ */
+int threaded_check_leading_path(struct cache_def *cache, const char *name, int len)
+{
 	int flags;
 	int match_len = lstat_cache_matchlen(cache, name, len, &flags,
 			   FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT);
@@ -240,7 +253,18 @@ int check_leading_path(const char *name, int len)
  */
 int has_dirs_only_path(const char *name, int len, int prefix_len)
 {
-	struct cache_def *cache = &default_cache;	/* FIXME */
+	return threaded_has_dirs_only_path(&default_cache, name, len, prefix_len);
+}
+
+/*
+ * Return non-zero if all path components of 'name' exists as a
+ * directory.  If prefix_len > 0, we will test with the stat()
+ * function instead of the lstat() function for a prefix length of
+ * 'prefix_len', thus we then allow for symlinks in the prefix part as
+ * long as those points to real existing directories.
+ */
+int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len)
+{
 	return lstat_cache(cache, name, len,
 			   FL_DIR|FL_FULLPATH, prefix_len) &
 		FL_DIR;