tree-walk: store object_id in a separate member

When parsing a tree, we read the object ID directly out of the tree
buffer. This is normally fine, but such an object ID cannot be used with
oidcpy, which copies GIT_MAX_RAWSZ bytes, because if we are using SHA-1,
there may not be that many bytes to copy.

Instead, store the object ID in a separate struct member. Since we can
no longer efficiently compute the path length, store that information as
well in struct name_entry. Ensure we only copy the object ID into the
new buffer if the path length is nonzero, as some callers will pass us
an empty path with no object ID following it, and we will not want to
read past the end of the buffer.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/tree-walk.h b/tree-walk.h
index 196831007e..08d349c54f 100644
--- a/tree-walk.h
+++ b/tree-walk.h
@@ -1,11 +1,14 @@
 #ifndef TREE_WALK_H
 #define TREE_WALK_H
 
+#include "cache.h"
+
 struct strbuf;
 
 struct name_entry {
-	const struct object_id *oid;
+	struct object_id oid;
 	const char *path;
+	int pathlen;
 	unsigned int mode;
 };
 
@@ -19,12 +22,12 @@ static inline const struct object_id *tree_entry_extract(struct tree_desc *desc,
 {
 	*pathp = desc->entry.path;
 	*modep = desc->entry.mode;
-	return desc->entry.oid;
+	return &desc->entry.oid;
 }
 
 static inline int tree_entry_len(const struct name_entry *ne)
 {
-	return (const char *)ne->oid - ne->path - 1;
+	return ne->pathlen;
 }
 
 /*