Move odb_backend implementors stuff into git2/sys

This moves some of the odb_backend stuff that is related to the
internals of an odb_backend implementation into include/git2/sys.

Some of the stuff related to streaming I left in include/git2
because it seemed like it would be reasonably needed by a normal
user who wanted to stream objects into and out of the ODB.

Also, I added APIs for traversing the list of backends so that
some of the tests would not need to access ODB internals.

1 files changed, 22 insertions, 0 deletions

diff --git a/src/odb.c b/src/odb.c
index c98df247c..ecdaf7ac2 100644
--- a/src/odb.c
+++ b/src/odb.c
@@ -8,6 +8,7 @@
 #include "common.h"
 #include <zlib.h>
 #include "git2/object.h"
+#include "git2/sys/odb_backend.h"
 #include "fileops.h"
 #include "hash.h"
 #include "odb.h"
@@ -403,6 +404,27 @@ int git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, int priority)
 	return add_backend_internal(odb, backend, priority, 1);
 }
 
+size_t git_odb_num_backends(git_odb *odb)
+{
+	assert(odb);
+	return odb->backends.length;
+}
+
+int git_odb_get_backend(git_odb_backend **out, git_odb *odb, size_t pos)
+{
+	backend_internal *internal;
+
+	assert(odb && odb);
+	internal = git_vector_get(&odb->backends, pos);
+
+	if (internal && internal->backend) {
+		*out = internal->backend;
+		return 0;
+	}
+
+	return GIT_ENOTFOUND;
+}
+
 static int add_default_backends(git_odb *db, const char *objects_dir, int as_alternates, int alternate_depth)
 {
 	git_odb_backend *loose, *packed;