[RFC/PATCH 1/3] refs: add a "for_each_replace_ref" function

This is some preparation work for the following patches that are using
the "refs/replace/" ref namespace.

Signed-off-by: Christian Couder <redacted>
---
 refs.c |    5 +++++
 refs.h |    1 +
 2 files changed, 6 insertions(+), 0 deletions(-)

	Junio wrote:

	> What I thought we
	> discussed during GitTogether was to write out the object name of the
	> replacement object in refs/replace/<sha1>.
	>
	> When the caller asks read_sha1_file() for an object whose object name is
	> <sha1>, you see if there is refs/replace/<sha1> in the repository, and
	> read the ref to learn the object name of the object that replaces it. 
	> And you return that as if it is the original object.
	
	Patch 2/3 in this series implements the new mechanism. As you can see I
	prefered it to be called when reading parent commits than from
	"read_sha1_file", because it seems to simplify things. I hope you still like
	it.

	Regards,
	Christian.

diff --git a/refs.c b/refs.c
index 33ced65..042106d 100644
--- a/refs.c
+++ b/refs.c

@@ -632,6 +632,11 @@ int for_each_remote_ref(each_ref_fn fn, void *cb_data)
 	return do_for_each_ref("refs/remotes/", fn, 13, cb_data);
 }
 
+int for_each_replace_ref(each_ref_fn fn, void *cb_data)
+{
+	return do_for_each_ref("refs/replace/", fn, 13, cb_data);
+}
+
 /*
  * Make sure "ref" is something reasonable to have under ".git/refs/";
  * We do not like it if:

diff --git a/refs.h b/refs.h
index 06ad260..8d2ee5a 100644
--- a/refs.h
+++ b/refs.h

@@ -23,6 +23,7 @@ extern int for_each_ref(each_ref_fn, void *);
 extern int for_each_tag_ref(each_ref_fn, void *);
 extern int for_each_branch_ref(each_ref_fn, void *);
 extern int for_each_remote_ref(each_ref_fn, void *);
+extern int for_each_replace_ref(each_ref_fn, void *);
 
 /*
  * Extra refs will be listed by for_each_ref() before any actual refs

-- 
1.6.1.162.g1cd53