From 7146e66f0861c720f9b32dc9d80ab80495a33e43 Mon Sep 17 00:00:00 2001 From: Kirill Smelkov Date: Thu, 6 Feb 2014 15:36:31 +0400 Subject: [PATCH] tree-walk: finally switch over tree descriptors to contain a pre-parsed entry This continues 4651ece8 (Switch over tree descriptors to contain a pre-parsed entry) and moves the only rest computational part mode = canon_mode(mode) from tree_entry_extract() to tree entry decode phase - to decode_tree_entry(). The reason to do it, is that canon_mode() is at least 2 conditional jumps for regular files, and that could be noticeable should canon_mode() be invoked several times. That does not matter for current Git codebase, where typical tree traversal is while (t->size) { sha1 = tree_entry_extract(t, &path, &mode); ... update_tree_entry(t); } i.e. we do t -> sha1,path.mode "extraction" only once per entry. In such cases, it does not matter performance-wise, where that mode canonicalization is done - either once in tree_entry_extract(), or once in decode_tree_entry() called by update_tree_entry() - it is approximately the same. But for future code, which could need to work with several tree_desc's in parallel, it could be handy to operate on tree_desc descriptors, and do "extracts" only when needed, or at all, access only relevant part of it through structure fields directly. And for such situations, having canon_mode() be done once in decode phase is better - we won't need to pay the performance price of 2 extra conditional jumps on every t->mode access. So let's move mode canonicalization to decode_tree_entry(). That was the final bit. Now after tree entry is decoded, it is fully ready and could be accessed either directly via field, or through tree_entry_extract() which this time got really "totally trivial". Signed-off-by: Kirill Smelkov Signed-off-by: Junio C Hamano --- tree-walk.c | 2 +- tree-walk.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tree-walk.c b/tree-walk.c index 79dba1d0f4..4dc86c7fe5 100644 --- a/tree-walk.c +++ b/tree-walk.c @@ -37,7 +37,7 @@ static void decode_tree_entry(struct tree_desc *desc, const char *buf, unsigned /* Initialize the descriptor entry */ desc->entry.path = path; - desc->entry.mode = mode; + desc->entry.mode = canon_mode(mode); desc->entry.sha1 = (const unsigned char *)(path + len); } diff --git a/tree-walk.h b/tree-walk.h index ae04b6417d..ae7fb3a824 100644 --- a/tree-walk.h +++ b/tree-walk.h @@ -16,7 +16,7 @@ struct tree_desc { static inline const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep) { *pathp = desc->entry.path; - *modep = canon_mode(desc->entry.mode); + *modep = desc->entry.mode; return desc->entry.sha1; }