[PATCH v2 01/16] name-hash: add index_dir_find()

["Jeff Hostetler via GitGitGadget" <gitgitgadget@gmail.com>]

From: Jeff Hostetler <jeffhostetler@github.com>

Replace the index_dir_exists() function with index_dir_find() and
change the API to take an optional strbuf to return the canonical
spelling of the matched directory prefix.

Create an index_dir_exists() wrapper macro for existing callers.

The existing index_dir_exists() returns a boolean to indicate if
there is a case-insensitive match in the directory name-hash, but
it doesn't tell the caller the exact spelling of that match.

The new version also copies the matched spelling to a provided strbuf.
This lets the caller, for example, then call index_name_pos() with the
correct case to search the cache-entry array for the real insertion
position.

Signed-off-by: Jeff Hostetler <jeffhostetler@github.com>
---
 name-hash.c | 9 ++++++++-
 name-hash.h | 7 ++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/name-hash.c b/name-hash.c
index 251f036eef6..3a58ce03d9c 100644
--- a/name-hash.c
+++ b/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;
 }
 
diff --git a/name-hash.h b/name-hash.h
index b1b4b0fb337..0cbfc428631 100644
--- a/name-hash.h
+++ b/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);
 
-- 
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