diff options
author | Kirill Smelkov <kirr@mns.spb.ru> | 2014-02-06 15:36:31 +0400 |
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committer | Junio C Hamano <gitster@pobox.com> | 2014-02-25 02:43:29 +0400 |
commit | 7146e66f0861c720f9b32dc9d80ab80495a33e43 (patch) | |
tree | 49e49eb7fda04ab77c98a188eebe5bee13cc5d5a /unimplemented.sh | |
parent | 6275c91c08f16f9d9aefea39ab7dab8560f50512 (diff) |
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 <kirr@mns.spb.ru>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'unimplemented.sh')
0 files changed, 0 insertions, 0 deletions