[PATCH 6/3] Export thread-safe version of 'has_symlink_leading_path()'

[Linus Torvalds <torvalds@linux-foundation.org>]

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Thu, 9 Jul 2009 13:35:31 -0700
Subject: [PATCH 6/3] Export thread-safe version of 'has_symlink_leading_path()'

The threaded index preloading will want it, so that it can avoid
locking by simply using a per-thread symlink/directory cache.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
This just exposes a thread-safe version of the symlink checking by 
allowing a caller to pass in its own local 'struct cache_def' to the 
function.

No users of this yet, but the next step is trivial and obvious..

 cache.h    |   10 ++++++++++
 symlinks.c |   21 ++++++++++-----------
 2 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/cache.h b/cache.h
index 871c984..f1e5ede 100644
--- a/cache.h
+++ b/cache.h
@@ -744,7 +744,17 @@ struct checkout {
 };
 
 extern int checkout_entry(struct cache_entry *ce, const struct checkout *state, char *topath);
+
+struct cache_def {
+	char path[PATH_MAX + 1];
+	int len;
+	int flags;
+	int track_flags;
+	int prefix_len_stat_func;
+};
+
 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 has_symlink_or_noent_leading_path(const char *name, int len);
 extern int has_dirs_only_path(const char *name, int len, int prefix_len);
 extern void invalidate_lstat_cache(const char *name, int len);
diff --git a/symlinks.c b/symlinks.c
index 08ad353..4bdded3 100644
--- a/symlinks.c
+++ b/symlinks.c
@@ -32,13 +32,7 @@ static int longest_path_match(const char *name_a, int len_a,
 	return match_len;
 }
 
-static struct cache_def {
-	char path[PATH_MAX + 1];
-	int len;
-	int flags;
-	int track_flags;
-	int prefix_len_stat_func;
-} default_cache;
+static struct cache_def default_cache;
 
 static inline void reset_lstat_cache(struct cache_def *cache)
 {
@@ -217,12 +211,17 @@ void clear_lstat_cache(void)
 /*
  * Return non-zero if path 'name' has a leading symlink component
  */
+int threaded_has_symlink_leading_path(struct cache_def *cache, const char *name, int len)
+{
+	return lstat_cache(cache, name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK;
+}
+
+/*
+ * Return non-zero if path 'name' has a leading symlink component
+ */
 int has_symlink_leading_path(const char *name, int len)
 {
-	struct cache_def *cache = &default_cache;	/* FIXME */
-	return lstat_cache(cache, name, len,
-			   FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) &
-		FL_SYMLINK;
+	return threaded_has_symlink_leading_path(&default_cache, name, len);
 }
 
 /*
-- 
1.6.3.3.415.ga8877