refs: read FETCH_HEAD and MERGE_HEAD generically

The FETCH_HEAD and MERGE_HEAD refs must be stored in a file, regardless of the
type of ref backend. This is because they can hold more than just a single ref.

To accomodate them for alternate ref backends, read them from a file generically
in refs_read_raw_ref()

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/refs.c b/refs.c
index 9e28912f73aa5f2a9cf0b9430e71bfde96485d3e..a2777793cfde5bb2324f77c23e212ca1b75eaf5b 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -1634,11 +1634,37 @@ int for_each_rawref(each_ref_fn fn, void *cb_data)
        return refs_for_each_rawref(get_main_ref_store(the_repository), fn, cb_data);
 }
 
+static int refs_read_special_head(struct ref_store *ref_store,
+                                 const char *refname, struct object_id *oid,
+                                 struct strbuf *referent, unsigned int *type)
+{
+       struct strbuf full_path = STRBUF_INIT;
+       struct strbuf content = STRBUF_INIT;
+       int result = -1;
+       strbuf_addf(&full_path, "%s/%s", ref_store->gitdir, refname);
+
+       if (strbuf_read_file(&content, full_path.buf, 0) < 0)
+               goto done;
+
+       result = parse_loose_ref_contents(content.buf, oid, referent, type);
+
+done:
+       strbuf_release(&full_path);
+       strbuf_release(&content);
+       return result;
+}
+
 int refs_read_raw_ref(struct ref_store *ref_store,
                      const char *refname, struct object_id *oid,
                      struct strbuf *referent, unsigned int *type)
 {
-       return ref_store->be->read_raw_ref(ref_store, refname, oid, referent, type);
+       if (!strcmp(refname, "FETCH_HEAD") || !strcmp(refname, "MERGE_HEAD")) {
+               return refs_read_special_head(ref_store, refname, oid, referent,
+                                             type);
+       }
+
+       return ref_store->be->read_raw_ref(ref_store, refname, oid, referent,
+                                          type);
 }
 
 /* This function needs to return a meaningful errno on failure */