Support reading attributes from index

Depending on the operation, we need to consider gitattributes
in both the work dir and the index.  This adds a parameter to
all of the gitattributes related functions that allows user
control of attribute reading behavior (i.e. prefer workdir,
prefer index, only use index).

This fix also covers allowing us to check attributes (and
hence do diff and status) on bare repositories.

This was a somewhat larger change that I hoped because it had
to change the cache key used for gitattributes files.

1 files changed, 13 insertions, 8 deletions

diff --git a/src/attr_file.h b/src/attr_file.h
index 10851bc49..ec488c4dc 100644
--- a/src/attr_file.h
+++ b/src/attr_file.h
@@ -48,7 +48,7 @@ typedef struct {
 } git_attr_assignment;
 
 typedef struct {
-	char *path;				/* cache the path this was loaded from */
+	char *key;				/* cache "source#path" this was loaded from */
 	git_vector rules;		/* vector of <rule*> or <fnmatch*> */
 	git_pool *pool;
 	bool pool_is_allocated;
@@ -61,20 +61,25 @@ typedef struct {
 	int         is_dir;
 } git_attr_path;
 
+typedef enum {
+	GIT_ATTR_FILE_FROM_FILE = 0,
+	GIT_ATTR_FILE_FROM_INDEX = 1
+} git_attr_file_source;
+
 /*
  * git_attr_file API
  */
 
-extern int git_attr_file__new(git_attr_file **attrs_ptr, git_pool *pool);
+extern int git_attr_file__new(
+	git_attr_file **attrs_ptr, git_attr_file_source src, const char *path, git_pool *pool);
+
+extern int git_attr_file__new_and_load(
+	git_attr_file **attrs_ptr, const char *path);
+
 extern void git_attr_file__free(git_attr_file *file);
 
-extern int git_attr_file__from_buffer(
+extern int git_attr_file__parse_buffer(
 	git_repository *repo, const char *buf, git_attr_file *file);
-extern int git_attr_file__from_file(
-	git_repository *repo, const char *path, git_attr_file *file);
-
-extern int git_attr_file__set_path(
-	git_repository *repo, const char *path, git_attr_file *file);
 
 extern int git_attr_file__lookup_one(
 	git_attr_file *file,