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Merge branch 'rs/refs-string-slice' 

Avoid unnecessary temporary allocations while looking for matching refs
inside refs API.

By René Scharfe (3) and Junio C Hamano (1)
* rs/refs-string-slice:
  refs: do not create ref_entry when searching
  refs: use strings directly in find_containing_dir()
  refs: convert parameter of create_dir_entry() to length-limited string
  refs: convert parameter of search_ref_dir() to length-limited string
This commit is contained in:
Junio C Hamano 2012-05-29 13:09:02 -07:00
parent 4dbfaee0c7 e1980c9d23
commit a7060009e1
1 changed files with 41 additions and 29 deletions
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70
refs.c
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@ -305,12 +305,13 @@ static void clear_ref_dir(struct ref_dir *dir)
* "refs/heads/") or "" for the top-level directory.
*/
static struct ref_entry *create_dir_entry(struct ref_cache *ref_cache,
const char *dirname, int incomplete)
const char *dirname, size_t len,
int incomplete)
{
struct ref_entry *direntry;
int len = strlen(dirname);
direntry = xcalloc(1, sizeof(struct ref_entry) + len + 1);
memcpy(direntry->name, dirname, len + 1);
memcpy(direntry->name, dirname, len);
direntry->name[len] = '\0';
direntry->u.subdir.ref_cache = ref_cache;
direntry->flag = REF_DIR | (incomplete ? REF_INCOMPLETE : 0);
return direntry;
@ -325,28 +326,42 @@ static int ref_entry_cmp(const void *a, const void *b)
static void sort_ref_dir(struct ref_dir *dir);
struct string_slice {
size_t len;
const char *str;
};
static int ref_entry_cmp_sslice(const void *key_, const void *ent_)
{
struct string_slice *key = (struct string_slice *)key_;
struct ref_entry *ent = *(struct ref_entry **)ent_;
int entlen = strlen(ent->name);
int cmplen = key->len < entlen ? key->len : entlen;
int cmp = memcmp(key->str, ent->name, cmplen);
if (cmp)
return cmp;
return key->len - entlen;
}
/*
* Return the entry with the given refname from the ref_dir
* (non-recursively), sorting dir if necessary. Return NULL if no
* such entry is found. dir must already be complete.
*/
static struct ref_entry *search_ref_dir(struct ref_dir *dir, const char *refname)
static struct ref_entry *search_ref_dir(struct ref_dir *dir,
const char *refname, size_t len)
{
struct ref_entry *e, **r;
int len;
struct ref_entry **r;
struct string_slice key;
if (refname == NULL || !dir->nr)
return NULL;
sort_ref_dir(dir);
len = strlen(refname) + 1;
e = xmalloc(sizeof(struct ref_entry) + len);
memcpy(e->name, refname, len);
r = bsearch(&e, dir->entries, dir->nr, sizeof(*dir->entries), ref_entry_cmp);
free(e);
key.len = len;
key.str = refname;
r = bsearch(&key, dir->entries, dir->nr, sizeof(*dir->entries),
ref_entry_cmp_sslice);
if (r == NULL)
return NULL;
@ -362,9 +377,10 @@ static struct ref_entry *search_ref_dir(struct ref_dir *dir, const char *refname
* directory cannot be found. dir must already be complete.
*/
static struct ref_dir *search_for_subdir(struct ref_dir *dir,
const char *subdirname, int mkdir)
const char *subdirname, size_t len,
int mkdir)
{
struct ref_entry *entry = search_ref_dir(dir, subdirname);
struct ref_entry *entry = search_ref_dir(dir, subdirname, len);
if (!entry) {
if (!mkdir)
return NULL;
@ -374,7 +390,7 @@ static struct ref_dir *search_for_subdir(struct ref_dir *dir,
* therefore, create an empty record for it but mark
* the record complete.
*/
entry = create_dir_entry(dir->ref_cache, subdirname, 0);
entry = create_dir_entry(dir->ref_cache, subdirname, len, 0);
add_entry_to_dir(dir, entry);
}
return get_ref_dir(entry);
@ -392,15 +408,11 @@ static struct ref_dir *search_for_subdir(struct ref_dir *dir,
static struct ref_dir *find_containing_dir(struct ref_dir *dir,
const char *refname, int mkdir)
{
struct strbuf dirname;
const char *slash;
strbuf_init(&dirname, PATH_MAX);
for (slash = strchr(refname, '/'); slash; slash = strchr(slash + 1, '/')) {
size_t dirnamelen = slash - refname + 1;
struct ref_dir *subdir;
strbuf_add(&dirname,
refname + dirname.len,
(slash + 1) - (refname + dirname.len));
subdir = search_for_subdir(dir, dirname.buf, mkdir);
subdir = search_for_subdir(dir, refname, dirnamelen, mkdir);
if (!subdir) {
dir = NULL;
break;
@ -408,7 +420,6 @@ static struct ref_dir *find_containing_dir(struct ref_dir *dir,
dir = subdir;
}
strbuf_release(&dirname);
return dir;
}
@ -423,7 +434,7 @@ static struct ref_entry *find_ref(struct ref_dir *dir, const char *refname)
dir = find_containing_dir(dir, refname, 0);
if (!dir)
return NULL;
entry = search_ref_dir(dir, refname);
entry = search_ref_dir(dir, refname, strlen(refname));
return (entry && !(entry->flag & REF_DIR)) ? entry : NULL;
}
@ -833,7 +844,7 @@ static struct ref_dir *get_packed_refs(struct ref_cache *refs)
const char *packed_refs_file;
FILE *f;
refs->packed = create_dir_entry(refs, "", 0);
refs->packed = create_dir_entry(refs, "", 0, 0);
if (*refs->name)
packed_refs_file = git_path_submodule(refs->name, "packed-refs");
else
@ -898,7 +909,8 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
} else if (S_ISDIR(st.st_mode)) {
strbuf_addch(&refname, '/');
add_entry_to_dir(dir,
create_dir_entry(refs, refname.buf, 1));
create_dir_entry(refs, refname.buf,
refname.len, 1));
} else {
if (*refs->name) {
hashclr(sha1);
@ -928,12 +940,12 @@ static struct ref_dir *get_loose_refs(struct ref_cache *refs)
* are about to read the only subdirectory that can
* hold references:
*/
refs->loose = create_dir_entry(refs, "", 0);
refs->loose = create_dir_entry(refs, "", 0, 0);
/*
* Create an incomplete entry for "refs/":
*/
add_entry_to_dir(get_ref_dir(refs->loose),
create_dir_entry(refs, "refs/", 1));
create_dir_entry(refs, "refs/", 5, 1));
}
return get_ref_dir(refs->loose);
}