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git/tree-walk.h
Kirill Smelkov 7146e66f08 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>
2014-02-24 14:43:29 -08:00

77 lines
2.2 KiB
C

#ifndef TREE_WALK_H
#define TREE_WALK_H
struct name_entry {
const unsigned char *sha1;
const char *path;
unsigned int mode;
};
struct tree_desc {
const void *buffer;
struct name_entry entry;
unsigned int size;
};
static inline const unsigned char *tree_entry_extract(struct tree_desc *desc, const char **pathp, unsigned int *modep)
{
*pathp = desc->entry.path;
*modep = desc->entry.mode;
return desc->entry.sha1;
}
static inline int tree_entry_len(const struct name_entry *ne)
{
return (const char *)ne->sha1 - ne->path - 1;
}
void update_tree_entry(struct tree_desc *);
void init_tree_desc(struct tree_desc *desc, const void *buf, unsigned long size);
/*
* Helper function that does both tree_entry_extract() and update_tree_entry()
* and returns true for success
*/
int tree_entry(struct tree_desc *, struct name_entry *);
void *fill_tree_descriptor(struct tree_desc *desc, const unsigned char *sha1);
struct traverse_info;
typedef int (*traverse_callback_t)(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *);
int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info);
struct traverse_info {
struct traverse_info *prev;
struct name_entry name;
int pathlen;
struct pathspec *pathspec;
unsigned long df_conflicts;
traverse_callback_t fn;
void *data;
int show_all_errors;
};
int get_tree_entry(const unsigned char *, const char *, unsigned char *, unsigned *);
extern char *make_traverse_path(char *path, const struct traverse_info *info, const struct name_entry *n);
extern void setup_traverse_info(struct traverse_info *info, const char *base);
static inline int traverse_path_len(const struct traverse_info *info, const struct name_entry *n)
{
return info->pathlen + tree_entry_len(n);
}
/* in general, positive means "kind of interesting" */
enum interesting {
all_entries_not_interesting = -1, /* no, and no subsequent entries will be either */
entry_not_interesting = 0,
entry_interesting = 1,
all_entries_interesting = 2 /* yes, and all subsequent entries will be */
};
extern enum interesting tree_entry_interesting(const struct name_entry *,
struct strbuf *, int,
const struct pathspec *ps);
#endif