tree_entry_interesting(): remove dependency on struct diff_options

This function can be potentially used in more places than just
tree-diff.c. "struct diff_options" does not make much sense outside
diff_tree_sha1().

While removing the use of diff_options, it also removes
tree_entry_extract() call, which means S_ISDIR() uses the entry->mode
directly, without being filtered by canon_mode() (called internally
inside tree_entry_extract).

The only use of the mode information in this function is to check the
type of the entry by giving it to S_ISDIR() macro, and the result does
not change with or without canon_mode(), so it is ok to bypass
tree_entry_extract().

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

tree-diff.c

@@ -93,24 +93,19 @@ static int compare_tree_entry(struct tree_desc *t1, struct tree_desc *t2, const
  *  - zero for no
  *  - negative for "no, and no subsequent entries will be either"
  */
-static int tree_entry_interesting(struct tree_desc *desc, const char *base, int baselen, struct diff_options *opt)
+static int tree_entry_interesting(const struct name_entry *entry, const char *base, int baselen, const struct pathspec *ps)
 {
-	const char *path;
-	const unsigned char *sha1;
-	unsigned mode;
 	int i;
 	int pathlen;
 	int never_interesting = -1;
 
-	if (!opt->pathspec.nr)
+	if (!ps || !ps->nr)
 		return 2;
 
-	sha1 = tree_entry_extract(desc, &path, &mode);
-
-	pathlen = tree_entry_len(path, sha1);
+	pathlen = tree_entry_len(entry->path, entry->sha1);
 
-	for (i = 0; i < opt->pathspec.nr; i++) {
-		const struct pathspec_item *item = opt->pathspec.items+i;
+	for (i = 0; i < ps->nr; i++) {
+		const struct pathspec_item *item = ps->items+i;
 		const char *match = item->match;
 		int matchlen = item->len;
 		int m = -1; /* signals that we haven't called strncmp() */
@@ -150,7 +145,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 			 * Does match sort strictly earlier than path
 			 * with their common parts?
 			 */
-			m = strncmp(match, path,
+			m = strncmp(match, entry->path,
 				    (matchlen < pathlen) ? matchlen : pathlen);
 			if (m < 0)
 				continue;
@@ -177,7 +172,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 		if (matchlen > pathlen) {
 			if (match[pathlen] != '/')
 				continue;
-			if (!S_ISDIR(mode))
+			if (!S_ISDIR(entry->mode))
 				continue;
 		}
 
@@ -186,7 +181,7 @@ static int tree_entry_interesting(struct tree_desc *desc, const char *base, int
 			 * we cheated and did not do strncmp(), so we do
 			 * that here.
 			 */
-			m = strncmp(match, path, pathlen);
+			m = strncmp(match, entry->path, pathlen);
 
 		/*
 		 * If common part matched earlier then it is a hit,
@@ -209,8 +204,7 @@ static void show_tree(struct diff_options *opt, const char *prefix, struct tree_
 		if (all_interesting)
 			show = 1;
 		else {
-			show = tree_entry_interesting(desc, base, baselen,
-						      opt);
+			show = tree_entry_interesting(&desc->entry, base, baselen, &opt->pathspec);
 			if (show == 2)
 				all_interesting = 1;
 		}
@@ -263,7 +257,7 @@ static void show_entry(struct diff_options *opt, const char *prefix, struct tree
 static void skip_uninteresting(struct tree_desc *t, const char *base, int baselen, struct diff_options *opt, int *all_interesting)
 {
 	while (t->size) {
-		int show = tree_entry_interesting(t, base, baselen, opt);
+		int show = tree_entry_interesting(&t->entry, base, baselen, &opt->pathspec);
 		if (show == 2)
 			*all_interesting = 1;
 		if (!show) {