diff.c: do not use a separate "size cache".

diff_filespec has a slot to record the size of the data already,
so make use of it instead of a separate size cache.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff.c

@@ -16,8 +16,6 @@
 #define FAST_WORKING_DIRECTORY 1
 #endif
 
-static int use_size_cache;
-
 static int diff_detect_rename_default;
 static int diff_rename_limit_default = -1;
 static int diff_use_color_default;
@@ -1408,55 +1406,6 @@ static int reuse_worktree_file(const char *name, const unsigned char *sha1, int
 	return 1;
 }
 
-static struct sha1_size_cache {
-	unsigned char sha1[20];
-	unsigned long size;
-} **sha1_size_cache;
-static int sha1_size_cache_nr, sha1_size_cache_alloc;
-
-static struct sha1_size_cache *locate_size_cache(unsigned char *sha1,
-						 int find_only,
-						 unsigned long size)
-{
-	int first, last;
-	struct sha1_size_cache *e;
-
-	first = 0;
-	last = sha1_size_cache_nr;
-	while (last > first) {
-		int cmp, next = (last + first) >> 1;
-		e = sha1_size_cache[next];
-		cmp = hashcmp(e->sha1, sha1);
-		if (!cmp)
-			return e;
-		if (cmp < 0) {
-			last = next;
-			continue;
-		}
-		first = next+1;
-	}
-	/* not found */
-	if (find_only)
-		return NULL;
-	/* insert to make it at "first" */
-	if (sha1_size_cache_alloc <= sha1_size_cache_nr) {
-		sha1_size_cache_alloc = alloc_nr(sha1_size_cache_alloc);
-		sha1_size_cache = xrealloc(sha1_size_cache,
-					   sha1_size_cache_alloc *
-					   sizeof(*sha1_size_cache));
-	}
-	sha1_size_cache_nr++;
-	if (first < sha1_size_cache_nr)
-		memmove(sha1_size_cache + first + 1, sha1_size_cache + first,
-			(sha1_size_cache_nr - first - 1) *
-			sizeof(*sha1_size_cache));
-	e = xmalloc(sizeof(struct sha1_size_cache));
-	sha1_size_cache[first] = e;
-	hashcpy(e->sha1, sha1);
-	e->size = size;
-	return e;
-}
-
 static int populate_from_stdin(struct diff_filespec *s)
 {
 #define INCREMENT 1024
@@ -1512,12 +1461,12 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only)
 	if (S_ISDIR(s->mode))
 		return -1;
 
-	if (!use_size_cache)
-		size_only = 0;
-
 	if (s->data)
 		return 0;
 
+	if (size_only && 0 < s->size)
+		return 0;
+
 	if (S_ISDIRLNK(s->mode))
 		return diff_populate_gitlink(s, size_only);
 
@@ -1579,19 +1528,8 @@ int diff_populate_filespec(struct diff_filespec *s, int size_only)
 	}
 	else {
 		enum object_type type;
-		struct sha1_size_cache *e;
-
-		if (size_only && use_size_cache &&
-		    (e = locate_size_cache(s->sha1, 1, 0)) != NULL) {
-			s->size = e->size;
-			return 0;
-		}
-
-		if (size_only) {
+		if (size_only)
 			type = sha1_object_info(s->sha1, &s->size);
-			if (use_size_cache && 0 < type)
-				locate_size_cache(s->sha1, 0, s->size);
-		}
 		else {
 			s->data = read_sha1_file(s->sha1, &type, &s->size);
 			s->should_free = 1;
@@ -2102,8 +2040,6 @@ int diff_setup_done(struct diff_options *options)
 			 */
 			read_cache();
 	}
-	if (options->setup & DIFF_SETUP_USE_SIZE_CACHE)
-		use_size_cache = 1;
 	if (options->abbrev <= 0 || 40 < options->abbrev)
 		options->abbrev = 40; /* full */