dir: create untracked_cache_invalidate_trimmed_path()

Create a wrapper function for untracked_cache_invalidate_path()
that silently trims a trailing slash, if present, before calling
the wrapped function.

The untracked cache expects to be called with a pathname that
does not contain a trailing slash.  This can make it inconvenient
for callers that have a directory path.  Lets hide this complexity.

This will be used by a later commit in the FSMonitor code which
may receive directory pathnames from an FSEvent.

Signed-off-by: Jeff Hostetler <jeffhostetler@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

dir.c

@@ -3918,6 +3918,26 @@ void untracked_cache_invalidate_path(struct index_state *istate,
 				 path, strlen(path));
 }
 
+void untracked_cache_invalidate_trimmed_path(struct index_state *istate,
+					     const char *path,
+					     int safe_path)
+{
+	size_t len = strlen(path);
+
+	if (!len)
+		BUG("untracked_cache_invalidate_trimmed_path given zero length path");
+
+	if (path[len - 1] != '/') {
+		untracked_cache_invalidate_path(istate, path, safe_path);
+	} else {
+		struct strbuf tmp = STRBUF_INIT;
+
+		strbuf_add(&tmp, path, len - 1);
+		untracked_cache_invalidate_path(istate, tmp.buf, safe_path);
+		strbuf_release(&tmp);
+	}
+}
+
 void untracked_cache_remove_from_index(struct index_state *istate,
 				       const char *path)
 {

dir.h

@@ -576,6 +576,13 @@ int cmp_dir_entry(const void *p1, const void *p2);
 int check_dir_entry_contains(const struct dir_entry *out, const struct dir_entry *in);
 
 void untracked_cache_invalidate_path(struct index_state *, const char *, int safe_path);
+/*
+ * Invalidate the untracked-cache for this path, but first strip
+ * off a trailing slash, if present.
+ */
+void untracked_cache_invalidate_trimmed_path(struct index_state *,
+					     const char *path,
+					     int safe_path);
 void untracked_cache_remove_from_index(struct index_state *, const char *);
 void untracked_cache_add_to_index(struct index_state *, const char *);