From 60b458b7d31ff2497ed90cbe9f65444d84882cec Mon Sep 17 00:00:00 2001 From: Kjetil Barvik Date: Mon, 9 Feb 2009 21:54:04 +0100 Subject: [PATCH] lstat_cache(): small cleanup and optimisation 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 Signed-off-by: Junio C Hamano --- symlinks.c | 44 ++++++++++++++++++++++++-------------------- 1 file changed, 24 insertions(+), 20 deletions(-) diff --git a/symlinks.c b/symlinks.c index f262b7c44..ae57e5603 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 -- 2.30.2