refactor get_textconv to not require diff_filespec

This function actually does two things:

  1. Load the userdiff driver for the filespec.

  2. Decide whether the driver has a textconv component, and
     initialize the textconv cache if applicable.

Only part (1) requires the filespec object, and some callers
may not have a filespec at all. So let's split them it into
two functions, and put part (2) with the userdiff code,
which is a better fit.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/userdiff.h b/userdiff.h
index 942d594..4a7e78f 100644
--- a/userdiff.h
+++ b/userdiff.h
@@ -23,4 +23,6 @@ int userdiff_config(const char *k, const char *v);
 struct userdiff_driver *userdiff_find_by_name(const char *name);
 struct userdiff_driver *userdiff_find_by_path(const char *path);
 
+struct userdiff_driver *userdiff_get_textconv(struct userdiff_driver *driver);
+
 #endif /* USERDIFF */