name-hash: add index_dir_find()

index_dir_exists() returns a boolean to indicate if there is a
case-insensitive match in the directory name-hash, but does not
provide the caller with the exact spelling of that match.

Create index_dir_find() to do the case-insensitive search *and*
optionally return the spelling of the matched directory prefix in a
provided strbuf.

To avoid code duplication, convert index_dir_exists() to be a trivial
wrapper around the new index_dir_find().

Signed-off-by: Jeff Hostetler <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: jeffhostetler

name-hash.c

@@ -685,13 +685,20 @@ static int same_name(const struct cache_entry *ce, const char *name, int namelen
 	return slow_same_name(name, namelen, ce->name, len);
 }
 
-int index_dir_exists(struct index_state *istate, const char *name, int namelen)
+int index_dir_find(struct index_state *istate, const char *name, int namelen,
+		   struct strbuf *canonical_path)
 {
 	struct dir_entry *dir;
 
 	lazy_init_name_hash(istate);
 	expand_to_path(istate, name, namelen, 0);
 	dir = find_dir_entry(istate, name, namelen);
+
+	if (canonical_path && dir && dir->nr) {
+		strbuf_reset(canonical_path);
+		strbuf_add(canonical_path, dir->name, dir->namelen);
+	}
+
 	return dir && dir->nr;
 }
 

name-hash.h

@@ -4,7 +4,12 @@
 struct cache_entry;
 struct index_state;
 
-int index_dir_exists(struct index_state *istate, const char *name, int namelen);
+
+int index_dir_find(struct index_state *istate, const char *name, int namelen,
+		   struct strbuf *canonical_path);
+
+#define index_dir_exists(i, n, l) index_dir_find((i), (n), (l), NULL)
+
 void adjust_dirname_case(struct index_state *istate, char *name);
 struct cache_entry *index_file_exists(struct index_state *istate, const char *name, int namelen, int igncase);