Merge branch 'eb/hash-transition'

Work to support a repository that work with both SHA-1 and SHA-256
hash algorithms has started.

* eb/hash-transition: (30 commits)
  t1016-compatObjectFormat: add tests to verify the conversion between objects
  t1006: test oid compatibility with cat-file
  t1006: rename sha1 to oid
  test-lib: compute the compatibility hash so tests may use it
  builtin/ls-tree: let the oid determine the output algorithm
  object-file: handle compat objects in check_object_signature
  tree-walk: init_tree_desc take an oid to get the hash algorithm
  builtin/cat-file: let the oid determine the output algorithm
  rev-parse: add an --output-object-format parameter
  repository: implement extensions.compatObjectFormat
  object-file: update object_info_extended to reencode objects
  object-file-convert: convert commits that embed signed tags
  object-file-convert: convert commit objects when writing
  object-file-convert: don't leak when converting tag objects
  object-file-convert: convert tag objects when writing
  object-file-convert: add a function to convert trees between algorithms
  object: factor out parse_mode out of fast-import and tree-walk into in object.h
  cache: add a function to read an OID of a specific algorithm
  tag: sign both hashes
  commit: export add_header_signature to support handling signatures on tags
  ...

1 files changed, 24 insertions, 0 deletions

diff --git a/object-file-convert.h b/object-file-convert.h
new file mode 100644
index 0000000000..a4f802aa8e
--- /dev/null
+++ b/object-file-convert.h
@@ -0,0 +1,24 @@
+#ifndef OBJECT_CONVERT_H
+#define OBJECT_CONVERT_H
+
+struct repository;
+struct object_id;
+struct git_hash_algo;
+struct strbuf;
+#include "object.h"
+
+int repo_oid_to_algop(struct repository *repo, const struct object_id *src,
+		      const struct git_hash_algo *to, struct object_id *dest);
+
+/*
+ * Convert an object file from one hash algorithm to another algorithm.
+ * Return -1 on failure, 0 on success.
+ */
+int convert_object_file(struct strbuf *outbuf,
+			const struct git_hash_algo *from,
+			const struct git_hash_algo *to,
+			const void *buf, size_t len,
+			enum object_type type,
+			int gentle);
+
+#endif /* OBJECT_CONVERT_H */