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name-hash: refactor polymorphic index_name_exists() 

Depending upon the absence or presence of a trailing '/' on the incoming
pathname, index_name_exists() checks either if a file is present in the
index or if a directory is represented within the index. Each caller
explicitly chooses the mode of operation by adding or removing a
trailing '/' before invoking index_name_exists().

Since these two modes of operations are disjoint and have no code in
common (one searches index_state.name_hash; the other dir_hash), they
can be represented more naturally as distinct functions: one to search
for a file, and one for a directory.

Splitting index searching into two functions relieves callers of the
artificial burden of having to add or remove a slash to select the mode
of operation; instead they just call the desired function. A subsequent
patch will take advantage of this benefit in order to eliminate the
requirement that the incoming pathname for a directory search must have
a trailing slash.

(In order to avoid disturbing in-flight topics, index_name_exists() is
retained as a thin wrapper dispatching either to index_dir_exists() or
index_file_exists().)

Signed-off-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Eric Sunshine 2013-09-17 03:06:14 -04:00 committed by Junio C Hamano
parent b3e7d24ca1
commit db5360f3f4
2 changed files with 34 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
cache.h
View File

@ -314,6 +314,8 @@ extern void free_name_hash(struct index_state *istate);
#define refresh_cache(flags) refresh_index(&the_index, (flags), NULL, NULL, NULL)
#define ce_match_stat(ce, st, options) ie_match_stat(&the_index, (ce), (st), (options))
#define ce_modified(ce, st, options) ie_modified(&the_index, (ce), (st), (options))
#define cache_dir_exists(name, namelen) index_dir_exists(&the_index, (name), (namelen))
#define cache_file_exists(name, namelen, igncase) index_file_exists(&the_index, (name), (namelen), (igncase))
#define cache_name_exists(name, namelen, igncase) index_name_exists(&the_index, (name), (namelen), (igncase))
#define cache_name_is_other(name, namelen) index_name_is_other(&the_index, (name), (namelen))
#define resolve_undo_clear() resolve_undo_clear_index(&the_index)
@ -463,6 +465,8 @@ extern int write_index(struct index_state *, int newfd);
extern int discard_index(struct index_state *);
extern int unmerged_index(const struct index_state *);
extern int verify_path(const char *path);
extern struct cache_entry *index_dir_exists(struct index_state *istate, const char *name, int namelen);
extern struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int igncase);
extern struct cache_entry *index_name_exists(struct index_state *istate, const char *name, int namelen, int igncase);
extern int index_name_pos(const struct index_state *, const char *name, int namelen);
#define ADD_CACHE_OK_TO_ADD 1 /* Ok to add */

54
name-hash.c
View File

@ -222,7 +222,29 @@ static int same_name(const struct cache_entry *ce, const char *name, int namelen
return slow_same_name(name, namelen, ce->name, len);
}
struct cache_entry *index_name_exists(struct index_state *istate, const char *name, int namelen, int icase)
struct cache_entry *index_dir_exists(struct index_state *istate, const char *name, int namelen)
{
struct cache_entry *ce;
struct dir_entry *dir;
lazy_init_name_hash(istate);
dir = find_dir_entry(istate, name, namelen);
if (dir && dir->nr)
return dir->ce;
/*
* It might be a submodule. Unlike plain directories, which are stored
* in the dir-hash, submodules are stored in the name-hash, so check
* there, as well.
*/
ce = index_file_exists(istate, name, namelen - 1, 1);
if (ce && S_ISGITLINK(ce->ce_mode))
return ce;
return NULL;
}
struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int icase)
{
unsigned int hash = hash_name(name, namelen);
struct cache_entry *ce;
@ -237,32 +259,16 @@ struct cache_entry *index_name_exists(struct index_state *istate, const char *na
}
ce = ce->next;
}
/*
* When looking for a directory (trailing '/'), it might be a
* submodule or a directory. Despite submodules being directories,
* they are stored in the name hash without a closing slash.
* When ignore_case is 1, directories are stored in a separate hash
* table *with* their closing slash.
*
* The side effect of this storage technique is we have need to
* lookup the directory in a separate hash table, and if not found
* remove the slash from name and perform the lookup again without
* the slash. If a match is made, S_ISGITLINK(ce->mode) will be
* true.
*/
if (icase && name[namelen - 1] == '/') {
struct dir_entry *dir = find_dir_entry(istate, name, namelen);
if (dir && dir->nr)
return dir->ce;
ce = index_name_exists(istate, name, namelen - 1, icase);
if (ce && S_ISGITLINK(ce->ce_mode))
return ce;
}
return NULL;
}
struct cache_entry *index_name_exists(struct index_state *istate, const char *name, int namelen, int icase)
{
if (namelen > 0 && name[namelen - 1] == '/')
return index_dir_exists(istate, name, namelen);
return index_file_exists(istate, name, namelen, icase);
}
static int free_dir_entry(void *entry, void *unused)
{
struct dir_entry *dir = entry;