Ref-count the filespecs used by diffcore

Rather than copy the filespecs when introducing new versions of them
(for rename or copy detection), use a refcount and increment the count
when reusing the diff_filespec.

This avoids unnecessary allocations, but the real reason behind this is
a future enhancement: we will want to track shared data across the
copy/rename detection.  In order to efficiently notice when a filespec
is used by a rename, the rename machinery wants to keep track of a
rename usage count which is shared across all different users of the
filespec.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Linus Torvalds 2007-10-25 11:19:10 -07:00 committed by Junio C Hamano
parent cb1491b6bf
commit 9fb88419ba
3 changed files with 19 additions and 14 deletions

15
diff.c
View File

@ -1440,9 +1440,18 @@ struct diff_filespec *alloc_filespec(const char *path)
memset(spec, 0, sizeof(*spec));
spec->path = (char *)(spec + 1);
memcpy(spec->path, path, namelen+1);
spec->count = 1;
return spec;
}
void free_filespec(struct diff_filespec *spec)
{
if (!--spec->count) {
diff_free_filespec_data(spec);
free(spec);
}
}
void fill_filespec(struct diff_filespec *spec, const unsigned char *sha1,
unsigned short mode)
{
@ -2435,10 +2444,8 @@ struct diff_filepair *diff_queue(struct diff_queue_struct *queue,
void diff_free_filepair(struct diff_filepair *p)
{
diff_free_filespec_data(p->one);
diff_free_filespec_data(p->two);
free(p->one);
free(p->two);
free_filespec(p->one);
free_filespec(p->two);
free(p);
}

View File

@ -209,21 +209,19 @@ static int estimate_similarity(struct diff_filespec *src,
static void record_rename_pair(int dst_index, int src_index, int score)
{
struct diff_filespec *one, *two, *src, *dst;
struct diff_filespec *src, *dst;
struct diff_filepair *dp;
if (rename_dst[dst_index].pair)
die("internal error: dst already matched.");
src = rename_src[src_index].one;
one = alloc_filespec(src->path);
fill_filespec(one, src->sha1, src->mode);
src->count++;
dst = rename_dst[dst_index].two;
two = alloc_filespec(dst->path);
fill_filespec(two, dst->sha1, dst->mode);
dst->count++;
dp = diff_queue(NULL, one, two);
dp = diff_queue(NULL, src, dst);
dp->renamed_pair = 1;
if (!strcmp(src->path, dst->path))
dp->score = rename_src[src_index].score;
@ -526,10 +524,8 @@ void diffcore_rename(struct diff_options *options)
}
}
for (i = 0; i < rename_dst_nr; i++) {
diff_free_filespec_data(rename_dst[i].two);
free(rename_dst[i].two);
}
for (i = 0; i < rename_dst_nr; i++)
free_filespec(rename_dst[i].two);
free(rename_dst);
rename_dst = NULL;

View File

@ -29,6 +29,7 @@ struct diff_filespec {
void *cnt_data;
const char *funcname_pattern_ident;
unsigned long size;
int count; /* Reference count */
int xfrm_flags; /* for use by the xfrm */
unsigned short mode; /* file mode */
unsigned sha1_valid : 1; /* if true, use sha1 and trust mode;
@ -43,6 +44,7 @@ struct diff_filespec {
};
extern struct diff_filespec *alloc_filespec(const char *);
extern void free_filespec(struct diff_filespec *);
extern void fill_filespec(struct diff_filespec *, const unsigned char *,
unsigned short);