Simplify the if-else test in longest_match_lstat_cache() such that we
only have one simple if test. Instead of testing for 'i == cache.len'
or 'i == len', we transform this to a common test for 'i == max_len'.
And to further optimise we use 'i >= max_len' instead of 'i ==
max_len', the reason is that it is now the exact opposite of one part
inside the while-loop termination expression 'i < max_len && name[i]
== cache.path[i]', and then the compiler can probably reuse a test
instruction from it.
We also throw away the arguments to reset_lstat_cache(), such that all
the safeguard logic inside lstat_cache() is handled at one place.
Signed-off-by: Kjetil Barvik <barvik@xxxxxxxxxxxx>
---
symlinks.c | 44 ++++++++++++++++++++++++--------------------
1 files changed, 24 insertions(+), 20 deletions(-)
diff --git a/symlinks.c b/symlinks.c
index f262b7c..ae57e56 100644
--- a/symlinks.c
+++ b/symlinks.c
@@ -25,27 +25,30 @@ static inline int longest_match_lstat_cache(int len, const char *name,
}
i++;
}
- /* Is the cached path string a substring of 'name'? */
- if (i == cache.len && cache.len < len && name[cache.len] == '/') {
- match_len_prev = match_len;
- match_len = cache.len;
- /* Is 'name' a substring of the cached path string? */
- } else if ((i == len && len < cache.len && cache.path[len] == '/') ||
- (i == len && len == cache.len)) {
+ /*
+ * Is the cached path string a substring of 'name', is 'name'
+ * a substring of the cached path string, or is 'name' and the
+ * cached path string the exact same string?
+ */
+ if (i >= max_len && ((len > cache.len && name[cache.len] == '/') ||
+ (len < cache.len && cache.path[len] == '/') ||
+ (len == cache.len))) {
match_len_prev = match_len;
- match_len = len;
+ match_len = i;
}
*previous_slash = match_len_prev;
return match_len;
}
-static inline void reset_lstat_cache(int track_flags, int prefix_len_stat_func)
+static inline void reset_lstat_cache(void)
{
cache.path[0] = '\0';
cache.len = 0;
cache.flags = 0;
- cache.track_flags = track_flags;
- cache.prefix_len_stat_func = prefix_len_stat_func;
+ /*
+ * The track_flags and prefix_len_stat_func members is only
+ * set by the safeguard rule inside lstat_cache()
+ */
}
#define FL_DIR (1 << 0)
@@ -77,11 +80,13 @@ static int lstat_cache(int len, const char *name,
if (cache.track_flags != track_flags ||
cache.prefix_len_stat_func != prefix_len_stat_func) {
/*
- * As a safeguard we clear the cache if the values of
- * track_flags and/or prefix_len_stat_func does not
- * match with the last supplied values.
+ * As a safeguard rule we clear the cache if the
+ * values of track_flags and/or prefix_len_stat_func
+ * does not match with the last supplied values.
*/
- reset_lstat_cache(track_flags, prefix_len_stat_func);
+ reset_lstat_cache();
+ cache.track_flags = track_flags;
+ cache.prefix_len_stat_func = prefix_len_stat_func;
match_len = last_slash = 0;
} else {
/*
@@ -153,7 +158,7 @@ static int lstat_cache(int len, const char *name,
cache.path[last_slash] = '\0';
cache.len = last_slash;
cache.flags = save_flags;
- } else if (track_flags & FL_DIR &&
+ } else if ((track_flags & FL_DIR) &&
last_slash_dir > 0 && last_slash_dir <= PATH_MAX) {
/*
* We have a separate test for the directory case,
@@ -170,7 +175,7 @@ static int lstat_cache(int len, const char *name,
cache.len = last_slash_dir;
cache.flags = FL_DIR;
} else {
- reset_lstat_cache(track_flags, prefix_len_stat_func);
+ reset_lstat_cache();
}
return ret_flags;
}
@@ -190,8 +195,7 @@ void invalidate_lstat_cache(int len, const char *name)
cache.len = previous_slash;
cache.flags = FL_DIR;
} else
- reset_lstat_cache(cache.track_flags,
- cache.prefix_len_stat_func);
+ reset_lstat_cache();
}
}
@@ -200,7 +204,7 @@ void invalidate_lstat_cache(int len, const char *name)
*/
void clear_lstat_cache(void)
{
- reset_lstat_cache(0, 0);
+ reset_lstat_cache();
}
#define USE_ONLY_LSTAT 0
--
1.6.1.349.g99fa5
--
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