thodg/libgit2

diff --git a/include/git2/commit.h b/include/git2/commit.h
index 764053e..0f76012 100644
--- a/include/git2/commit.h
+++ b/include/git2/commit.h
@@ -201,14 +201,12 @@ GIT_EXTERN(int) git_commit_nth_gen_ancestor(
 	unsigned int n);
 
 /**
- * Create a new commit in the repository using `git_object`
- * instances as parameters.
+ * Create new commit in the repository from a list of `git_object` pointers
  *
- * The message will not be cleaned up. This can be achieved
- * through `git_message_prettify()`.
+ * The message will not be cleaned up automatically. You can do that with
+ * the `git_message_prettify()` function.
  *
- * @param id Pointer where to store the OID of the
- *	newly created commit
+ * @param id Pointer in which to store the OID of the newly created commit
  *
  * @param repo Repository where to store the commit
  *
@@ -219,73 +217,69 @@ GIT_EXTERN(int) git_commit_nth_gen_ancestor(
  *	make it point to this commit. If the reference doesn't
  *	exist yet, it will be created.
  *
- * @param author Signature representing the author and the authory
- *	time of this commit
+ * @param author Signature with author and author time of commit
  *
- * @param committer Signature representing the committer and the
- * commit time of this commit
+ * @param committer Signature with committer and * commit time of commit
  *
  * @param message_encoding The encoding for the message in the
- * commit, represented with a standard encoding name.
- * E.g. "UTF-8". If NULL, no encoding header is written and
- * UTF-8 is assumed.
+ *  commit, represented with a standard encoding name.
+ *  E.g. "UTF-8". If NULL, no encoding header is written and
+ *  UTF-8 is assumed.
  *
  * @param message Full message for this commit
  *
  * @param tree An instance of a `git_tree` object that will
- * be used as the tree for the commit. This tree object must
- * also be owned by the given `repo`.
+ *  be used as the tree for the commit. This tree object must
+ *  also be owned by the given `repo`.
  *
  * @param parent_count Number of parents for this commit
  *
  * @param parents[] Array of `parent_count` pointers to `git_commit`
- * objects that will be used as the parents for this commit. This
- * array may be NULL if `parent_count` is 0 (root commit). All the
- * given commits must be owned by the `repo`.
+ *  objects that will be used as the parents for this commit. This
+ *  array may be NULL if `parent_count` is 0 (root commit). All the
+ *  given commits must be owned by the `repo`.
  *
  * @return 0 or an error code
  *	The created commit will be written to the Object Database and
  *	the given reference will be updated to point to it
  */
 GIT_EXTERN(int) git_commit_create(
-		git_oid *id,
-		git_repository *repo,
-		const char *update_ref,
-		const git_signature *author,
-		const git_signature *committer,
-		const char *message_encoding,
-		const char *message,
-		const git_tree *tree,
-		int parent_count,
-		const git_commit *parents[]);
+	git_oid *id,
+	git_repository *repo,
+	const char *update_ref,
+	const git_signature *author,
+	const git_signature *committer,
+	const char *message_encoding,
+	const char *message,
+	const git_tree *tree,
+	int parent_count,
+	const git_commit *parents[]);
 
 /**
- * Create a new commit in the repository using a variable
- * argument list.
+ * Create new commit in the repository using a variable argument list.
  *
- * The message will be cleaned up from excess whitespace
- * it will be made sure that the last line ends with a '\n'.
+ * The message will be cleaned up from excess whitespace and it will be made
+ * sure that the last line ends with a '\n'.
  *
- * The parents for the commit are specified as a variable
- * list of pointers to `const git_commit *`. Note that this
- * is a convenience method which may not be safe to export
- * for certain languages or compilers
+ * The parents for the commit are specified as a variable list of pointers
+ * to `const git_commit *`. Note that this is a convenience method which may
+ * not be safe to export for certain languages or compilers
  *
- * All other parameters remain the same
+ * All other parameters remain the same at `git_commit_create()`.
  *
  * @see git_commit_create
  */
 GIT_EXTERN(int) git_commit_create_v(
-		git_oid *id,
-		git_repository *repo,
-		const char *update_ref,
-		const git_signature *author,
-		const git_signature *committer,
-		const char *message_encoding,
-		const char *message,
-		const git_tree *tree,
-		int parent_count,
-		...);
+	git_oid *id,
+	git_repository *repo,
+	const char *update_ref,
+	const git_signature *author,
+	const git_signature *committer,
+	const char *message_encoding,
+	const char *message,
+	const git_tree *tree,
+	int parent_count,
+	...);
 
 /** @} */
 GIT_END_DECL
diff --git a/include/git2/config.h b/include/git2/config.h
index 19d4cb7..5a2f956 100644
--- a/include/git2/config.h
+++ b/include/git2/config.h
@@ -43,29 +43,6 @@ typedef struct {
 
 typedef int  (*git_config_foreach_cb)(const git_config_entry *, void *);
 
-
-/**
- * Generic backend that implements the interface to
- * access a configuration file
- */
-struct git_config_backend {
-	unsigned int version;
-	struct git_config *cfg;
-
-	/* Open means open the file/database and parse if necessary */
-	int (*open)(struct git_config_backend *, unsigned int level);
-	int (*get)(const struct git_config_backend *, const char *key, const git_config_entry **entry);
-	int (*get_multivar)(struct git_config_backend *, const char *key, const char *regexp, git_config_foreach_cb callback, void *payload);
-	int (*set)(struct git_config_backend *, const char *key, const char *value);
-	int (*set_multivar)(git_config_backend *cfg, const char *name, const char *regexp, const char *value);
-	int (*del)(struct git_config_backend *, const char *key);
-	int (*foreach)(struct git_config_backend *, const char *, git_config_foreach_cb callback, void *payload);
-	int (*refresh)(struct git_config_backend *);
-	void (*free)(struct git_config_backend *);
-};
-#define GIT_CONFIG_BACKEND_VERSION 1
-#define GIT_CONFIG_BACKEND_INIT {GIT_CONFIG_BACKEND_VERSION}
-
 typedef enum {
 	GIT_CVAR_FALSE = 0,
 	GIT_CVAR_TRUE = 1,
@@ -154,30 +131,6 @@ GIT_EXTERN(int) git_config_open_default(git_config **out);
 GIT_EXTERN(int) git_config_new(git_config **out);
 
 /**
- * Add a generic config file instance to an existing config
- *
- * Note that the configuration object will free the file
- * automatically.
- *
- * Further queries on this config object will access each
- * of the config file instances in order (instances with
- * a higher priority level will be accessed first).
- *
- * @param cfg the configuration to add the file to
- * @param file the configuration file (backend) to add
- * @param level the priority level of the backend
- * @param force if a config file already exists for the given
- *  priority level, replace it
- * @return 0 on success, GIT_EEXISTS when adding more than one file
- *  for a given priority level (and force_replace set to 0), or error code
- */
-GIT_EXTERN(int) git_config_add_backend(
-	git_config *cfg,
-	git_config_backend *file,
-	unsigned int level,
-	int force);
-
-/**
  * Add an on-disk config file instance to an existing config
  *
  * The on-disk file pointed at by `path` will be opened and
@@ -192,10 +145,9 @@ GIT_EXTERN(int) git_config_add_backend(
  * a higher priority level will be accessed first).
  *
  * @param cfg the configuration to add the file to
- * @param path path to the configuration file (backend) to add
+ * @param path path to the configuration file to add
  * @param level the priority level of the backend
- * @param force if a config file already exists for the given
- *  priority level, replace it
+ * @param force replace config file at the given priority level
  * @return 0 on success, GIT_EEXISTS when adding more than one file
  *  for a given priority level (and force_replace set to 0),
  *  GIT_ENOTFOUND when the file doesn't exist or error code
diff --git a/include/git2/indexer.h b/include/git2/indexer.h
index dfe6ae5..262dcd1 100644
--- a/include/git2/indexer.h
+++ b/include/git2/indexer.h
@@ -8,31 +8,11 @@
 #define _INCLUDE_git_indexer_h__
 
 #include "common.h"
+#include "types.h"
 #include "oid.h"
 
 GIT_BEGIN_DECL
 
-/**
- * This is passed as the first argument to the callback to allow the
- * user to see the progress.
- */
-typedef struct git_transfer_progress {
-	unsigned int total_objects;
-	unsigned int indexed_objects;
-	unsigned int received_objects;
-	size_t received_bytes;
-} git_transfer_progress;
-
-
-/**
- * Type for progress callbacks during indexing.  Return a value less than zero
- * to cancel the transfer.
- *
- * @param stats Structure containing information about the state of the transfer
- * @param payload Payload provided by caller
- */
-typedef int (*git_transfer_progress_callback)(const git_transfer_progress *stats, void *payload);
-
 typedef struct git_indexer_stream git_indexer_stream;
 
 /**
diff --git a/include/git2/odb.h b/include/git2/odb.h
index 8fd1a95..b64436c 100644
--- a/include/git2/odb.h
+++ b/include/git2/odb.h
@@ -10,8 +10,6 @@
 #include "common.h"
 #include "types.h"
 #include "oid.h"
-#include "odb_backend.h"
-#include "indexer.h"
 
 /**
  * @file git2/odb.h
@@ -23,6 +21,11 @@
 GIT_BEGIN_DECL
 
 /**
+ * Function type for callbacks from git_odb_foreach.
+ */
+typedef int (*git_odb_foreach_cb)(const git_oid *id, void *payload);
+
+/**
  * Create a new object database with no backends.
  *
  * Before the ODB can be used for read/writing, a custom database
@@ -53,42 +56,6 @@ GIT_EXTERN(int) git_odb_new(git_odb **out);
 GIT_EXTERN(int) git_odb_open(git_odb **out, const char *objects_dir);
 
 /**
- * Add a custom backend to an existing Object DB
- *
- * The backends are checked in relative ordering, based on the
- * value of the `priority` parameter.
- *
- * Read <odb_backends.h> for more information.
- *
- * @param odb database to add the backend to
- * @param backend pointer to a git_odb_backend instance
- * @param priority Value for ordering the backends queue
- * @return 0 on success; error code otherwise
- */
-GIT_EXTERN(int) git_odb_add_backend(git_odb *odb, git_odb_backend *backend, int priority);
-
-/**
- * Add a custom backend to an existing Object DB; this
- * backend will work as an alternate.
- *
- * Alternate backends are always checked for objects *after*
- * all the main backends have been exhausted.
- *
- * The backends are checked in relative ordering, based on the
- * value of the `priority` parameter.
- *
- * Writing is disabled on alternate backends.
- *
- * Read <odb_backends.h> for more information.
- *
- * @param odb database to add the backend to
- * @param backend pointer to a git_odb_backend instance
- * @param priority Value for ordering the backends queue
- * @return 0 on success; error code otherwise
- */
-GIT_EXTERN(int) git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, int priority);
-
-/**
  * Add an on-disk alternate to an existing Object DB.
  *
  * Note that the added path must point to an `objects`, not
@@ -406,6 +373,60 @@ GIT_EXTERN(size_t) git_odb_object_size(git_odb_object *object);
  */
 GIT_EXTERN(git_otype) git_odb_object_type(git_odb_object *object);
 
+/**
+ * Add a custom backend to an existing Object DB
+ *
+ * The backends are checked in relative ordering, based on the
+ * value of the `priority` parameter.
+ *
+ * Read <odb_backends.h> for more information.
+ *
+ * @param odb database to add the backend to
+ * @param backend pointer to a git_odb_backend instance
+ * @param priority Value for ordering the backends queue
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_odb_add_backend(git_odb *odb, git_odb_backend *backend, int priority);
+
+/**
+ * Add a custom backend to an existing Object DB; this
+ * backend will work as an alternate.
+ *
+ * Alternate backends are always checked for objects *after*
+ * all the main backends have been exhausted.
+ *
+ * The backends are checked in relative ordering, based on the
+ * value of the `priority` parameter.
+ *
+ * Writing is disabled on alternate backends.
+ *
+ * Read <odb_backends.h> for more information.
+ *
+ * @param odb database to add the backend to
+ * @param backend pointer to a git_odb_backend instance
+ * @param priority Value for ordering the backends queue
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_odb_add_alternate(git_odb *odb, git_odb_backend *backend, int priority);
+
+/**
+ * Get the number of ODB backend objects
+ *
+ * @param odb object database
+ * @return number of backends in the ODB
+ */
+GIT_EXTERN(size_t) git_odb_num_backends(git_odb *odb);
+
+/**
+ * Lookup an ODB backend object by index
+ *
+ * @param out output pointer to ODB backend at pos
+ * @param odb object database
+ * @param pos index into object database backend list
+ * @return 0 on success; GIT_ENOTFOUND if pos is invalid; other errors < 0
+ */
+GIT_EXTERN(int) git_odb_get_backend(git_odb_backend **out, git_odb *odb, size_t pos);
+
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/include/git2/odb_backend.h b/include/git2/odb_backend.h
index dbc3981..d38005d 100644
--- a/include/git2/odb_backend.h
+++ b/include/git2/odb_backend.h
@@ -7,106 +7,24 @@
 #ifndef INCLUDE_git_odb_backend_h__
 #define INCLUDE_git_odb_backend_h__
 
-#include "common.h"
-#include "types.h"
-#include "oid.h"
-#include "indexer.h"
+#include "git2/common.h"
+#include "git2/types.h"
 
 /**
  * @file git2/backend.h
  * @brief Git custom backend functions
- * @defgroup git_backend Git custom backend API
+ * @defgroup git_odb Git object database routines
  * @ingroup Git
  * @{
  */
 GIT_BEGIN_DECL
 
-struct git_odb_stream;
-struct git_odb_writepack;
-
-/**
- * Function type for callbacks from git_odb_foreach.
- */
-typedef int (*git_odb_foreach_cb)(const git_oid *id, void *payload);
-
 /**
- * An instance for a custom backend
+ * Constructors for in-box ODB backends.
  */
-struct git_odb_backend {
-	unsigned int version;
-	git_odb *odb;
-
-	/* read and read_prefix each return to libgit2 a buffer which
-	 * will be freed later. The buffer should be allocated using
-	 * the function git_odb_backend_malloc to ensure that it can
-	 * be safely freed later. */
-	int (* read)(
-			void **, size_t *, git_otype *,
-			struct git_odb_backend *,
-			const git_oid *);
-
-	/* To find a unique object given a prefix
-	 * of its oid.
-	 * The oid given must be so that the
-	 * remaining (GIT_OID_HEXSZ - len)*4 bits
-	 * are 0s.
-	 */
-	int (* read_prefix)(
-			git_oid *,
-			void **, size_t *, git_otype *,
-			struct git_odb_backend *,
-			const git_oid *,
-			size_t);
-
-	int (* read_header)(
-			size_t *, git_otype *,
-			struct git_odb_backend *,
-			const git_oid *);
-
-	/* The writer may assume that the object
-	 * has already been hashed and is passed
-	 * in the first parameter.
-	 */
-	int (* write)(
-			git_oid *,
-			struct git_odb_backend *,
-			const void *,
-			size_t,
-			git_otype);
-
-	int (* writestream)(
-			struct git_odb_stream **,
-			struct git_odb_backend *,
-			size_t,
-			git_otype);
-
-	int (* readstream)(
-			struct git_odb_stream **,
-			struct git_odb_backend *,
-			const git_oid *);
-
-	int (* exists)(
-			struct git_odb_backend *,
-			const git_oid *);
-
-	int (* refresh)(struct git_odb_backend *);
-
-	int (* foreach)(
-			struct git_odb_backend *,
-			git_odb_foreach_cb cb,
-			void *payload);
-
-	int (* writepack)(
-			struct git_odb_writepack **,
-			struct git_odb_backend *,
-			git_transfer_progress_callback progress_cb,
-			void *progress_payload);
-
-	void (* free)(struct git_odb_backend *);
-};
-
-#define GIT_ODB_BACKEND_VERSION 1
-#define GIT_ODB_BACKEND_INIT {GIT_ODB_BACKEND_VERSION}
+GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **out, const char *objects_dir);
+GIT_EXTERN(int) git_odb_backend_loose(git_odb_backend **out, const char *objects_dir, int compression_level, int do_fsync);
+GIT_EXTERN(int) git_odb_backend_one_pack(git_odb_backend **out, const char *index_file);
 
 /** Streaming mode */
 enum {
@@ -117,33 +35,24 @@ enum {
 
 /** A stream to read/write from a backend */
 struct git_odb_stream {
-	struct git_odb_backend *backend;
+	git_odb_backend *backend;
 	unsigned int mode;
 
-	int (*read)(struct git_odb_stream *stream, char *buffer, size_t len);
-	int (*write)(struct git_odb_stream *stream, const char *buffer, size_t len);
-	int (*finalize_write)(git_oid *oid_p, struct git_odb_stream *stream);
-	void (*free)(struct git_odb_stream *stream);
+	int (*read)(git_odb_stream *stream, char *buffer, size_t len);
+	int (*write)(git_odb_stream *stream, const char *buffer, size_t len);
+	int (*finalize_write)(git_oid *oid_p, git_odb_stream *stream);
+	void (*free)(git_odb_stream *stream);
 };
 
 /** A stream to write a pack file to the ODB */
 struct git_odb_writepack {
-	struct git_odb_backend *backend;
+	git_odb_backend *backend;
 
-	int (*add)(struct git_odb_writepack *writepack, const void *data, size_t size, git_transfer_progress *stats);
-	int (*commit)(struct git_odb_writepack *writepack, git_transfer_progress *stats);
-	void (*free)(struct git_odb_writepack *writepack);
+	int (*add)(git_odb_writepack *writepack, const void *data, size_t size, git_transfer_progress *stats);
+	int (*commit)(git_odb_writepack *writepack, git_transfer_progress *stats);
+	void (*free)(git_odb_writepack *writepack);
 };
 
-GIT_EXTERN(void *) git_odb_backend_malloc(git_odb_backend *backend, size_t len);
-
-/**
- * Constructors for in-box ODB backends.
- */
-GIT_EXTERN(int) git_odb_backend_pack(git_odb_backend **out, const char *objects_dir);
-GIT_EXTERN(int) git_odb_backend_loose(git_odb_backend **out, const char *objects_dir, int compression_level, int do_fsync);
-GIT_EXTERN(int) git_odb_backend_one_pack(git_odb_backend **out, const char *index_file);
-
 GIT_END_DECL
 
 #endif
diff --git a/include/git2/refdb.h b/include/git2/refdb.h
index 0e3ec5e..a315876 100644
--- a/include/git2/refdb.h
+++ b/include/git2/refdb.h
@@ -22,25 +22,6 @@
 GIT_BEGIN_DECL
 
 /**
- * Create a new reference.  Either an oid or a symbolic target must be
- * specified.
- *
- * @param refdb the reference database to associate with this reference
- * @param name the reference name
- * @param oid the object id for a direct reference
- * @param symbolic the target for a symbolic reference
- * @return the created git_reference or NULL on error
- */
-GIT_EXTERN(git_reference *) git_reference__alloc(
-	const char *name,
-	const git_oid *oid,
-	const git_oid *peel);
-
-GIT_EXTERN(git_reference *) git_reference__alloc_symbolic(
-	const char *name,
-	const char *target);
-
-/**
  * Create a new reference database with no backends.
  *
  * Before the Ref DB can be used for read/writing, a custom database
@@ -81,20 +62,6 @@ GIT_EXTERN(int) git_refdb_compress(git_refdb *refdb);
  */
 GIT_EXTERN(void) git_refdb_free(git_refdb *refdb);
 
-/**
- * Sets the custom backend to an existing reference DB
- *
- * Read <refdb_backends.h> for more information.
- *
- * @param refdb database to add the backend to
- * @param backend pointer to a git_refdb_backend instance
- * @param priority Value for ordering the backends queue
- * @return 0 on success; error code otherwise
- */
-GIT_EXTERN(int) git_refdb_set_backend(
-	git_refdb *refdb,
-	git_refdb_backend *backend);
-
 /** @} */
 GIT_END_DECL
 
diff --git a/include/git2/refdb_backend.h b/include/git2/refdb_backend.h
deleted file mode 100644
index 20eb6a9..0000000
--- a/include/git2/refdb_backend.h
+++ /dev/null
@@ -1,108 +0,0 @@
-/*
- * Copyright (C) the libgit2 contributors. All rights reserved.
- *
- * This file is part of libgit2, distributed under the GNU GPL v2 with
- * a Linking Exception. For full terms see the included COPYING file.
- */
-#ifndef INCLUDE_git_refdb_backend_h__
-#define INCLUDE_git_refdb_backend_h__
-
-#include "common.h"
-#include "types.h"
-#include "oid.h"
-
-/**
- * @file git2/refdb_backend.h
- * @brief Git custom refs backend functions
- * @defgroup git_refdb_backend Git custom refs backend API
- * @ingroup Git
- * @{
- */
-GIT_BEGIN_DECL
-
-/** An instance for a custom backend */
-struct git_refdb_backend {
-    unsigned int version;
-
-	/**
-	 * Queries the refdb backend to determine if the given ref_name
-	 * exists.  A refdb implementation must provide this function.
-	 */
-	int (*exists)(
-		int *exists,
-		struct git_refdb_backend *backend,
-		const char *ref_name);
-
-	/**
-	 * Queries the refdb backend for a given reference.  A refdb
-	 * implementation must provide this function.
-	 */
-	int (*lookup)(
-		git_reference **out,
-		struct git_refdb_backend *backend,
-		const char *ref_name);
-
-	/**
-	 * Enumerates each reference in the refdb.  A refdb implementation must
-	 * provide this function.
-	 */
-	int (*foreach)(
-		struct git_refdb_backend *backend,
-		unsigned int list_flags,
-		git_reference_foreach_cb callback,
-		void *payload);
-
-	/**
-	 * Enumerates each reference in the refdb that matches the given
-	 * glob string.  A refdb implementation may provide this function;
-	 * if it is not provided, foreach will be used and the results filtered
-	 * against the glob.
-	 */
-	int (*foreach_glob)(
-		struct git_refdb_backend *backend,
-		const char *glob,
-		unsigned int list_flags,
-		git_reference_foreach_cb callback,
-		void *payload);
-
-	/**
-	 * Writes the given reference to the refdb.  A refdb implementation
-	 * must provide this function.
-	 */
-	int (*write)(struct git_refdb_backend *backend, const git_reference *ref);
-
-	/**
-	 * Deletes the given reference from the refdb.  A refdb implementation
-	 * must provide this function.
-	 */
-	int (*delete)(struct git_refdb_backend *backend, const git_reference *ref);
-
-	/**
-	 * Suggests that the given refdb compress or optimize its references.
-	 * This mechanism is implementation specific.  (For on-disk reference
-	 * databases, this may pack all loose references.)    A refdb
-	 * implementation may provide this function; if it is not provided,
-	 * nothing will be done.
-	 */
-	int (*compress)(struct git_refdb_backend *backend);
-
-	/**
-	 * Frees any resources held by the refdb.  A refdb implementation may
-	 * provide this function; if it is not provided, nothing will be done.
-	 */
-	void (*free)(struct git_refdb_backend *backend);
-};
-
-#define GIT_ODB_BACKEND_VERSION 1
-#define GIT_ODB_BACKEND_INIT {GIT_ODB_BACKEND_VERSION}
-
-/**
- * Constructors for default refdb backends.
- */
-GIT_EXTERN(int) git_refdb_backend_fs(
-	struct git_refdb_backend **backend_out,
-	git_repository *repo);
-
-GIT_END_DECL
-
-#endif
diff --git a/include/git2/repository.h b/include/git2/repository.h
index ed837b3..08024cd 100644
--- a/include/git2/repository.h
+++ b/include/git2/repository.h
@@ -401,21 +401,6 @@ GIT_EXTERN(int) git_repository_is_bare(git_repository *repo);
 GIT_EXTERN(int) git_repository_config(git_config **out, git_repository *repo);
 
 /**
- * Set the configuration file for this repository
- *
- * This configuration file will be used for all configuration
- * queries involving this repository.
- *
- * The repository will keep a reference to the config file;
- * the user must still free the config after setting it
- * to the repository, or it will leak.
- *
- * @param repo A repository object
- * @param config A Config object
- */
-GIT_EXTERN(void) git_repository_set_config(git_repository *repo, git_config *config);
-
-/**
  * Get the Object Database for this repository.
  *
  * If a custom ODB has not been set, the default
@@ -432,21 +417,6 @@ GIT_EXTERN(void) git_repository_set_config(git_repository *repo, git_config *con
 GIT_EXTERN(int) git_repository_odb(git_odb **out, git_repository *repo);
 
 /**
- * Set the Object Database for this repository
- *
- * The ODB will be used for all object-related operations
- * involving this repository.
- *
- * The repository will keep a reference to the ODB; the user
- * must still free the ODB object after setting it to the
- * repository, or it will leak.
- *
- * @param repo A repository object
- * @param odb An ODB object
- */
-GIT_EXTERN(void) git_repository_set_odb(git_repository *repo, git_odb *odb);
-
-/**
  * Get the Reference Database Backend for this repository.
  *
  * If a custom refsdb has not been set, the default database for
@@ -463,23 +433,6 @@ GIT_EXTERN(void) git_repository_set_odb(git_repository *repo, git_odb *odb);
 GIT_EXTERN(int) git_repository_refdb(git_refdb **out, git_repository *repo);
 
 /**
- * Set the Reference Database Backend for this repository
- *
- * The refdb will be used for all reference related operations
- * involving this repository.
- *
- * The repository will keep a reference to the refdb; the user
- * must still free the refdb object after setting it to the
- * repository, or it will leak.
- *
- * @param repo A repository object
- * @param refdb An refdb object
- */
-GIT_EXTERN(void) git_repository_set_refdb(
-	git_repository *repo,
-	git_refdb *refdb);
-
-/**
  * Get the Index file for this repository.
  *
  * If a custom index has not been set, the default
@@ -496,21 +449,6 @@ GIT_EXTERN(void) git_repository_set_refdb(
 GIT_EXTERN(int) git_repository_index(git_index **out, git_repository *repo);
 
 /**
- * Set the index file for this repository
- *
- * This index will be used for all index-related operations
- * involving this repository.
- *
- * The repository will keep a reference to the index file;
- * the user must still free the index after setting it
- * to the repository, or it will leak.
- *
- * @param repo A repository object
- * @param index An index object
- */
-GIT_EXTERN(void) git_repository_set_index(git_repository *repo, git_index *index);
-
-/**
  * Retrieve git's prepared message
  *
  * Operations such as git revert/cherry-pick/merge with the -n option
diff --git a/include/git2/sys/commit.h b/include/git2/sys/commit.h
new file mode 100644
index 0000000..096e028
--- /dev/null
+++ b/include/git2/sys/commit.h
@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_commit_h__
+#define INCLUDE_sys_git_commit_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+#include "git2/oid.h"
+
+/**
+ * @file git2/sys/commit.h
+ * @brief Low-level Git commit creation
+ * @defgroup git_backend Git custom backend APIs
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Create new commit in the repository from a list of `git_oid` values
+ *
+ * See documentation for `git_commit_create()` for information about the
+ * parameters, as the meaning is identical excepting that `tree` and
+ * `parents` now take `git_oid`.  This is a dangerous API in that the
+ * `parents` list of `git_oid`s in not checked for validity.
+ */
+GIT_EXTERN(int) git_commit_create_from_oids(
+	git_oid *oid,
+	git_repository *repo,
+	const char *update_ref,
+	const git_signature *author,
+	const git_signature *committer,
+	const char *message_encoding,
+	const char *message,
+	const git_oid *tree,
+	int parent_count,
+	const git_oid *parents[]);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/include/git2/sys/config.h b/include/git2/sys/config.h
new file mode 100644
index 0000000..1c9deba
--- /dev/null
+++ b/include/git2/sys/config.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_config_backend_h__
+#define INCLUDE_sys_git_config_backend_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+#include "git2/config.h"
+
+/**
+ * @file git2/sys/config.h
+ * @brief Git config backend routines
+ * @defgroup git_backend Git custom backend APIs
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Generic backend that implements the interface to
+ * access a configuration file
+ */
+struct git_config_backend {
+	unsigned int version;
+	struct git_config *cfg;
+
+	/* Open means open the file/database and parse if necessary */
+	int (*open)(struct git_config_backend *, unsigned int level);
+	int (*get)(const struct git_config_backend *, const char *key, const git_config_entry **entry);
+	int (*get_multivar)(struct git_config_backend *, const char *key, const char *regexp, git_config_foreach_cb callback, void *payload);
+	int (*set)(struct git_config_backend *, const char *key, const char *value);
+	int (*set_multivar)(git_config_backend *cfg, const char *name, const char *regexp, const char *value);
+	int (*del)(struct git_config_backend *, const char *key);
+	int (*foreach)(struct git_config_backend *, const char *, git_config_foreach_cb callback, void *payload);
+	int (*refresh)(struct git_config_backend *);
+	void (*free)(struct git_config_backend *);
+};
+#define GIT_CONFIG_BACKEND_VERSION 1
+#define GIT_CONFIG_BACKEND_INIT {GIT_CONFIG_BACKEND_VERSION}
+
+/**
+ * Add a generic config file instance to an existing config
+ *
+ * Note that the configuration object will free the file
+ * automatically.
+ *
+ * Further queries on this config object will access each
+ * of the config file instances in order (instances with
+ * a higher priority level will be accessed first).
+ *
+ * @param cfg the configuration to add the file to
+ * @param file the configuration file (backend) to add
+ * @param level the priority level of the backend
+ * @param force if a config file already exists for the given
+ *  priority level, replace it
+ * @return 0 on success, GIT_EEXISTS when adding more than one file
+ *  for a given priority level (and force_replace set to 0), or error code
+ */
+GIT_EXTERN(int) git_config_add_backend(
+	git_config *cfg,
+	git_config_backend *file,
+	unsigned int level,
+	int force);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/include/git2/sys/odb_backend.h b/include/git2/sys/odb_backend.h
new file mode 100644
index 0000000..3cd2734
--- /dev/null
+++ b/include/git2/sys/odb_backend.h
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_odb_backend_h__
+#define INCLUDE_sys_git_odb_backend_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+#include "git2/oid.h"
+#include "git2/odb.h"
+
+/**
+ * @file git2/sys/backend.h
+ * @brief Git custom backend implementors functions
+ * @defgroup git_backend Git custom backend APIs
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * An instance for a custom backend
+ */
+struct git_odb_backend {
+	unsigned int version;
+	git_odb *odb;
+
+	/* read and read_prefix each return to libgit2 a buffer which
+	 * will be freed later. The buffer should be allocated using
+	 * the function git_odb_backend_malloc to ensure that it can
+	 * be safely freed later. */
+	int (* read)(
+		void **, size_t *, git_otype *, git_odb_backend *, const git_oid *);
+
+	/* To find a unique object given a prefix
+	 * of its oid.
+	 * The oid given must be so that the
+	 * remaining (GIT_OID_HEXSZ - len)*4 bits
+	 * are 0s.
+	 */
+	int (* read_prefix)(
+		git_oid *, void **, size_t *, git_otype *,
+		git_odb_backend *, const git_oid *, size_t);
+
+	int (* read_header)(
+		size_t *, git_otype *, git_odb_backend *, const git_oid *);
+
+	/* The writer may assume that the object
+	 * has already been hashed and is passed
+	 * in the first parameter.
+	 */
+	int (* write)(
+		git_oid *, git_odb_backend *, const void *, size_t, git_otype);
+
+	int (* writestream)(
+		git_odb_stream **, git_odb_backend *, size_t, git_otype);
+
+	int (* readstream)(
+		git_odb_stream **, git_odb_backend *, const git_oid *);
+
+	int (* exists)(
+		git_odb_backend *, const git_oid *);
+
+	int (* refresh)(git_odb_backend *);
+
+	int (* foreach)(
+		git_odb_backend *, git_odb_foreach_cb cb, void *payload);
+
+	int (* writepack)(
+		git_odb_writepack **, git_odb_backend *,
+		git_transfer_progress_callback progress_cb, void *progress_payload);
+
+	void (* free)(git_odb_backend *);
+};
+
+#define GIT_ODB_BACKEND_VERSION 1
+#define GIT_ODB_BACKEND_INIT {GIT_ODB_BACKEND_VERSION}
+
+GIT_EXTERN(void *) git_odb_backend_malloc(git_odb_backend *backend, size_t len);
+
+GIT_END_DECL
+
+#endif
diff --git a/include/git2/sys/refdb_backend.h b/include/git2/sys/refdb_backend.h
new file mode 100644
index 0000000..d5f599f
--- /dev/null
+++ b/include/git2/sys/refdb_backend.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_refdb_backend_h__
+#define INCLUDE_sys_git_refdb_backend_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+#include "git2/oid.h"
+
+/**
+ * @file git2/refdb_backend.h
+ * @brief Git custom refs backend functions
+ * @defgroup git_refdb_backend Git custom refs backend API
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/** An instance for a custom backend */
+struct git_refdb_backend {
+    unsigned int version;
+
+	/**
+	 * Queries the refdb backend to determine if the given ref_name
+	 * exists.  A refdb implementation must provide this function.
+	 */
+	int (*exists)(
+		int *exists,
+		git_refdb_backend *backend,
+		const char *ref_name);
+
+	/**
+	 * Queries the refdb backend for a given reference.  A refdb
+	 * implementation must provide this function.
+	 */
+	int (*lookup)(
+		git_reference **out,
+		git_refdb_backend *backend,
+		const char *ref_name);
+
+	/**
+	 * Enumerates each reference in the refdb.  A refdb implementation must
+	 * provide this function.
+	 */
+	int (*foreach)(
+		git_refdb_backend *backend,
+		unsigned int list_flags,
+		git_reference_foreach_cb callback,
+		void *payload);
+
+	/**
+	 * Enumerates each reference in the refdb that matches the given
+	 * glob string.  A refdb implementation may provide this function;
+	 * if it is not provided, foreach will be used and the results filtered
+	 * against the glob.
+	 */
+	int (*foreach_glob)(
+		git_refdb_backend *backend,
+		const char *glob,
+		unsigned int list_flags,
+		git_reference_foreach_cb callback,
+		void *payload);
+
+	/**
+	 * Writes the given reference to the refdb.  A refdb implementation
+	 * must provide this function.
+	 */
+	int (*write)(git_refdb_backend *backend, const git_reference *ref);
+
+	/**
+	 * Deletes the given reference from the refdb.  A refdb implementation
+	 * must provide this function.
+	 */
+	int (*delete)(git_refdb_backend *backend, const git_reference *ref);
+
+	/**
+	 * Suggests that the given refdb compress or optimize its references.
+	 * This mechanism is implementation specific.  (For on-disk reference
+	 * databases, this may pack all loose references.)    A refdb
+	 * implementation may provide this function; if it is not provided,
+	 * nothing will be done.
+	 */
+	int (*compress)(git_refdb_backend *backend);
+
+	/**
+	 * Frees any resources held by the refdb.  A refdb implementation may
+	 * provide this function; if it is not provided, nothing will be done.
+	 */
+	void (*free)(git_refdb_backend *backend);
+};
+
+#define GIT_ODB_BACKEND_VERSION 1
+#define GIT_ODB_BACKEND_INIT {GIT_ODB_BACKEND_VERSION}
+
+/**
+ * Constructors for default filesystem-based refdb backend
+ *
+ * Under normal usage, this is called for you when the repository is
+ * opened / created, but you can use this to explicitly construct a
+ * filesystem refdb backend for a repository.
+ *
+ * @param backend_out Output pointer to the git_refdb_backend object
+ * @param repo Git repository to access
+ * @return 0 on success, <0 error code on failure
+ */
+GIT_EXTERN(int) git_refdb_backend_fs(
+	git_refdb_backend **backend_out,
+	git_repository *repo);
+
+/**
+ * Sets the custom backend to an existing reference DB
+ *
+ * The `git_refdb` will take ownership of the `git_refdb_backend` so you
+ * should NOT free it after calling this function.
+ *
+ * @param refdb database to add the backend to
+ * @param backend pointer to a git_refdb_backend instance
+ * @return 0 on success; error code otherwise
+ */
+GIT_EXTERN(int) git_refdb_set_backend(
+	git_refdb *refdb,
+	git_refdb_backend *backend);
+
+GIT_END_DECL
+
+#endif
diff --git a/include/git2/sys/refs.h b/include/git2/sys/refs.h
new file mode 100644
index 0000000..8596325
--- /dev/null
+++ b/include/git2/sys/refs.h
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_refdb_h__
+#define INCLUDE_sys_git_refdb_h__
+
+#include "git2/common.h"
+#include "git2/types.h"
+#include "git2/oid.h"
+
+/**
+ * Create a new direct reference from an OID.
+ *
+ * @param name the reference name
+ * @param oid the object id for a direct reference
+ * @param symbolic the target for a symbolic reference
+ * @return the created git_reference or NULL on error
+ */
+GIT_EXTERN(git_reference *) git_reference__alloc(
+	const char *name,
+	const git_oid *oid,
+	const git_oid *peel);
+
+/**
+ * Create a new symbolic reference.
+ *
+ * @param name the reference name
+ * @param symbolic the target for a symbolic reference
+ * @return the created git_reference or NULL on error
+ */
+GIT_EXTERN(git_reference *) git_reference__alloc_symbolic(
+	const char *name,
+	const char *target);
+
+#endif
diff --git a/include/git2/sys/repository.h b/include/git2/sys/repository.h
new file mode 100644
index 0000000..34bc175
--- /dev/null
+++ b/include/git2/sys/repository.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+#ifndef INCLUDE_sys_git_repository_h__
+#define INCLUDE_sys_git_repository_h__
+
+/**
+ * @file git2/sys/repository.h
+ * @brief Git repository custom implementation routines
+ * @defgroup git_backend Git custom backend APIs
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Create a new repository with neither backends nor config object
+ *
+ * Note that this is only useful if you wish to associate the repository
+ * with a non-filesystem-backed object database and config store.
+ *
+ * @param out The blank repository
+ * @return 0 on success, or an error code
+ */
+GIT_EXTERN(int) git_repository_new(git_repository **out);
+
+/**
+ * Set the configuration file for this repository
+ *
+ * This configuration file will be used for all configuration
+ * queries involving this repository.
+ *
+ * The repository will keep a reference to the config file;
+ * the user must still free the config after setting it
+ * to the repository, or it will leak.
+ *
+ * @param repo A repository object
+ * @param config A Config object
+ */
+GIT_EXTERN(void) git_repository_set_config(git_repository *repo, git_config *config);
+
+/**
+ * Set the Object Database for this repository
+ *
+ * The ODB will be used for all object-related operations
+ * involving this repository.
+ *
+ * The repository will keep a reference to the ODB; the user
+ * must still free the ODB object after setting it to the
+ * repository, or it will leak.
+ *
+ * @param repo A repository object
+ * @param odb An ODB object
+ */
+GIT_EXTERN(void) git_repository_set_odb(git_repository *repo, git_odb *odb);
+
+/**
+ * Set the Reference Database Backend for this repository
+ *
+ * The refdb will be used for all reference related operations
+ * involving this repository.
+ *
+ * The repository will keep a reference to the refdb; the user
+ * must still free the refdb object after setting it to the
+ * repository, or it will leak.
+ *
+ * @param repo A repository object
+ * @param refdb An refdb object
+ */
+GIT_EXTERN(void) git_repository_set_refdb(git_repository *repo, git_refdb *refdb);
+
+/**
+ * Set the index file for this repository
+ *
+ * This index will be used for all index-related operations
+ * involving this repository.
+ *
+ * The repository will keep a reference to the index file;
+ * the user must still free the index after setting it
+ * to the repository, or it will leak.
+ *
+ * @param repo A repository object
+ * @param index An index object
+ */
+GIT_EXTERN(void) git_repository_set_index(git_repository *repo, git_index *index);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/include/git2/types.h b/include/git2/types.h
index bc15050..aca9ed9 100644
--- a/include/git2/types.h
+++ b/include/git2/types.h
@@ -196,6 +196,26 @@ typedef struct git_push git_push;
 typedef struct git_remote_head git_remote_head;
 typedef struct git_remote_callbacks git_remote_callbacks;
 
+/**
+ * This is passed as the first argument to the callback to allow the
+ * user to see the progress.
+ */
+typedef struct git_transfer_progress {
+	unsigned int total_objects;
+	unsigned int indexed_objects;
+	unsigned int received_objects;
+	size_t received_bytes;
+} git_transfer_progress;
+
+/**
+ * Type for progress callbacks during indexing.  Return a value less than zero
+ * to cancel the transfer.
+ *
+ * @param stats Structure containing information about the state of the transfer
+ * @param payload Payload provided by caller
+ */
+typedef int (*git_transfer_progress_callback)(const git_transfer_progress *stats, void *payload);
+
 /** @} */
 GIT_END_DECL
 
diff --git a/src/blob.c b/src/blob.c
index c0514fc..11e1f4d 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -8,6 +8,7 @@
 #include "git2/common.h"
 #include "git2/object.h"
 #include "git2/repository.h"
+#include "git2/odb_backend.h"
 
 #include "common.h"
 #include "blob.h"
diff --git a/src/commit.c b/src/commit.c
index c7b83ed..dd41692 100644
--- a/src/commit.c
+++ b/src/commit.c
@@ -9,6 +9,7 @@
 #include "git2/object.h"
 #include "git2/repository.h"
 #include "git2/signature.h"
+#include "git2/sys/commit.h"
 
 #include "common.h"
 #include "odb.h"
@@ -44,16 +45,16 @@ void git_commit__free(git_commit *commit)
 }
 
 int git_commit_create_v(
-		git_oid *oid,
-		git_repository *repo,
-		const char *update_ref,
-		const git_signature *author,
-		const git_signature *committer,
-		const char *message_encoding,
-		const char *message,
-		const git_tree *tree,
-		int parent_count,
-		...)
+	git_oid *oid,
+	git_repository *repo,
+	const char *update_ref,
+	const git_signature *author,
+	const git_signature *committer,
+	const char *message_encoding,
+	const char *message,
+	const git_tree *tree,
+	int parent_count,
+	...)
 {
 	va_list ap;
 	int i, res;
@@ -76,30 +77,29 @@ int git_commit_create_v(
 	return res;
 }
 
-int git_commit_create(
-		git_oid *oid,
-		git_repository *repo,
-		const char *update_ref,
-		const git_signature *author,
-		const git_signature *committer,
-		const char *message_encoding,
-		const char *message,
-		const git_tree *tree,
-		int parent_count,
-		const git_commit *parents[])
+int git_commit_create_from_oids(
+	git_oid *oid,
+	git_repository *repo,
+	const char *update_ref,
+	const git_signature *author,
+	const git_signature *committer,
+	const char *message_encoding,
+	const char *message,
+	const git_oid *tree,
+	int parent_count,
+	const git_oid *parents[])
 {
 	git_buf commit = GIT_BUF_INIT;
 	int i;
 	git_odb *odb;
 
+	assert(oid && repo && tree && parent_count >= 0);
 	assert(git_object_owner((const git_object *)tree) == repo);
 
-	git_oid__writebuf(&commit, "tree ", git_object_id((const git_object *)tree));
+	git_oid__writebuf(&commit, "tree ", tree);
 
-	for (i = 0; i < parent_count; ++i) {
-		assert(git_object_owner((const git_object *)parents[i]) == repo);
-		git_oid__writebuf(&commit, "parent ", git_object_id((const git_object *)parents[i]));
-	}
+	for (i = 0; i < parent_count; ++i)
+		git_oid__writebuf(&commit, "parent ", parents[i]);
 
 	git_signature__writebuf(&commit, "author ", author);
 	git_signature__writebuf(&commit, "committer ", committer);
@@ -131,6 +131,41 @@ on_error:
 	return -1;
 }
 
+int git_commit_create(
+	git_oid *oid,
+	git_repository *repo,
+	const char *update_ref,
+	const git_signature *author,
+	const git_signature *committer,
+	const char *message_encoding,
+	const char *message,
+	const git_tree *tree,
+	int parent_count,
+	const git_commit *parents[])
+{
+	int retval, i;
+	const git_oid **parent_oids;
+
+	assert(parent_count >= 0);
+
+	parent_oids = git__malloc(parent_count * sizeof(git_oid *));
+	GITERR_CHECK_ALLOC(parent_oids);
+
+	for (i = 0; i < parent_count; ++i) {
+		assert(git_object_owner((const git_object *)parents[i]) == repo);
+		parent_oids[i] = git_object_id((const git_object *)parents[i]);
+	}
+
+	retval = git_commit_create_from_oids(
+		oid, repo, update_ref, author, committer,
+		message_encoding, message,
+		git_object_id((const git_object *)tree), parent_count, parent_oids);
+
+	git__free((void *)parent_oids);
+
+	return retval;
+}
+
 int git_commit__parse_buffer(git_commit *commit, const void *data, size_t len)
 {
 	const char *buffer = data;
diff --git a/src/config.c b/src/config.c
index 5379b0e..1283522 100644
--- a/src/config.c
+++ b/src/config.c
@@ -9,6 +9,7 @@
 #include "fileops.h"
 #include "config.h"
 #include "git2/config.h"
+#include "git2/sys/config.h"
 #include "vector.h"
 #include "buf_text.h"
 #include "config_file.h"
diff --git a/src/config_file.c b/src/config_file.c
index 8b51ab2..a4ff8bb 100644
--- a/src/config_file.c
+++ b/src/config_file.c
@@ -12,6 +12,7 @@
 #include "buffer.h"
 #include "buf_text.h"
 #include "git2/config.h"
+#include "git2/sys/config.h"
 #include "git2/types.h"
 #include "strmap.h"
 
diff --git a/src/odb.c b/src/odb.c
index c98df24..ecdaf7a 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;
diff --git a/src/odb_loose.c b/src/odb_loose.c
index 68083f7..e78172c 100644
--- a/src/odb_loose.c
+++ b/src/odb_loose.c
@@ -8,7 +8,7 @@
 #include "common.h"
 #include <zlib.h>
 #include "git2/object.h"
-#include "git2/oid.h"
+#include "git2/sys/odb_backend.h"
 #include "fileops.h"
 #include "hash.h"
 #include "odb.h"
diff --git a/src/odb_pack.c b/src/odb_pack.c
index 7240a4a..773e149 100644
--- a/src/odb_pack.c
+++ b/src/odb_pack.c
@@ -8,7 +8,8 @@
 #include "common.h"
 #include <zlib.h>
 #include "git2/repository.h"
-#include "git2/oid.h"
+#include "git2/indexer.h"
+#include "git2/sys/odb_backend.h"
 #include "fileops.h"
 #include "hash.h"
 #include "odb.h"
diff --git a/src/refdb.c b/src/refdb.c
index 2a0fd70..33a1934 100644
--- a/src/refdb.c
+++ b/src/refdb.c
@@ -7,15 +7,16 @@
 
 #include "common.h"
 #include "posix.h"
+
 #include "git2/object.h"
 #include "git2/refs.h"
 #include "git2/refdb.h"
+#include "git2/sys/refdb_backend.h"
+
 #include "hash.h"
 #include "refdb.h"
 #include "refs.h"
 
-#include "git2/refdb_backend.h"
-
 int git_refdb_new(git_refdb **out, git_repository *repo)
 {
 	git_refdb *db;
@@ -57,15 +58,19 @@ int git_refdb_open(git_refdb **out, git_repository *repo)
 	return 0;
 }
 
-int git_refdb_set_backend(git_refdb *db, git_refdb_backend *backend)
+static void refdb_free_backend(git_refdb *db)
 {
 	if (db->backend) {
-		if(db->backend->free)
+		if (db->backend->free)
 			db->backend->free(db->backend);
 		else
 			git__free(db->backend);
 	}
+}
 
+int git_refdb_set_backend(git_refdb *db, git_refdb_backend *backend)
+{
+	refdb_free_backend(db);
 	db->backend = backend;
 
 	return 0;
@@ -74,23 +79,16 @@ int git_refdb_set_backend(git_refdb *db, git_refdb_backend *backend)
 int git_refdb_compress(git_refdb *db)
 {
 	assert(db);
-	
-	if (db->backend->compress) {
+
+	if (db->backend->compress)
 		return db->backend->compress(db->backend);
-	}
-	
+
 	return 0;
 }
 
 static void refdb_free(git_refdb *db)
 {
-	if (db->backend) {
-		if(db->backend->free)
-			db->backend->free(db->backend);
-		else
-			git__free(db->backend);
-	}
-
+	refdb_free_backend(db);
 	git__free(db);
 }
 
@@ -114,14 +112,13 @@ int git_refdb_lookup(git_reference **out, git_refdb *db, const char *ref_name)
 	git_reference *ref;
 	int error;
 
-	assert(db && db->backend && ref_name);
-
-	*out = NULL;
+	assert(db && db->backend && out && ref_name);
 
-	if ((error = db->backend->lookup(&ref, db->backend, ref_name)) == 0)
-	{
+	if (!(error = db->backend->lookup(&ref, db->backend, ref_name))) {
 		ref->db = db;
 		*out = ref;
+	} else {
+		*out = NULL;
 	}
 
 	return error;
diff --git a/src/refdb.h b/src/refdb.h
index 0969711..047113a 100644
--- a/src/refdb.h
+++ b/src/refdb.h
@@ -41,6 +41,6 @@ int git_refdb_foreach_glob(
 
 int git_refdb_write(git_refdb *refdb, const git_reference *ref);
 
-int git_refdb_delete(struct git_refdb *refdb, const git_reference *ref);
+int git_refdb_delete(git_refdb *refdb, const git_reference *ref);
 
 #endif
diff --git a/src/refdb_fs.c b/src/refdb_fs.c
index 56b2b6a..4438710 100644
--- a/src/refdb_fs.c
+++ b/src/refdb_fs.c
@@ -18,7 +18,8 @@
 #include <git2/tag.h>
 #include <git2/object.h>
 #include <git2/refdb.h>
-#include <git2/refdb_backend.h>
+#include <git2/sys/refdb_backend.h>
+#include <git2/sys/refs.h>
 
 GIT__USE_STRMAP;
 
@@ -61,7 +62,7 @@ static int reference_read(
 	/* Determine the full path of the file */
 	if (git_buf_joinpath(&path, repo_path, ref_name) < 0)
 		return -1;
-	
+
 	result = git_futils_readbuffer_updated(file_content, path.ptr, mtime, NULL, updated);
 	git_buf_free(&path);
 
@@ -174,7 +175,7 @@ static int packed_load(refdb_fs_backend *backend)
 		ref_cache->packfile = git_strmap_alloc();
 		GITERR_CHECK_ALLOC(ref_cache->packfile);
 	}
-	
+
 	result = reference_read(&packfile, &ref_cache->packfile_time,
 		backend->path, GIT_PACKEDREFS_FILE, &updated);
 
@@ -192,7 +193,7 @@ static int packed_load(refdb_fs_backend *backend)
 
 	if (result < 0)
 		return -1;
-	
+
 	if (!updated)
 		return 0;
 
@@ -433,7 +434,7 @@ static int loose_lookup(
 	} else {
 		if ((error = loose_parse_oid(&oid, &ref_file)) < 0)
 			goto done;
-		
+
 		*out = git_reference__alloc(ref_name, &oid, NULL);
 	}
 
@@ -455,19 +456,19 @@ static int packed_map_entry(
 
 	if (packed_load(backend) < 0)
 		return -1;
-	
+
 	/* Look up on the packfile */
 	packfile_refs = backend->refcache.packfile;
 
 	*pos = git_strmap_lookup_index(packfile_refs, ref_name);
-	
+
 	if (!git_strmap_valid_index(packfile_refs, *pos)) {
 		giterr_set(GITERR_REFERENCE, "Reference '%s' not found", ref_name);
 		return GIT_ENOTFOUND;
 	}
 
 	*entry = git_strmap_value_at(packfile_refs, *pos);
-	
+
 	return 0;
 }
 
@@ -479,14 +480,14 @@ static int packed_lookup(
 	struct packref *entry;
 	khiter_t pos;
 	int error = 0;
-	
+
 	if ((error = packed_map_entry(&entry, &pos, backend, ref_name)) < 0)
 		return error;
 
 	if ((*out = git_reference__alloc(ref_name,
 		&entry->oid, &entry->peel)) == NULL)
 		return -1;
-	
+
 	return 0;
 }
 
@@ -582,7 +583,7 @@ static int refdb_fs_backend__foreach(
 	git_buf refs_path = GIT_BUF_INIT;
 	const char *ref_name;
 	void *ref = NULL;
-	
+
 	GIT_UNUSED(ref);
 
 	assert(_backend);
@@ -590,7 +591,7 @@ static int refdb_fs_backend__foreach(
 
 	if (packed_load(backend) < 0)
 		return -1;
-	
+
 	/* list all the packed references first */
 	if (list_type & GIT_REF_OID) {
 		git_strmap_foreach(backend->refcache.packfile, ref_name, ref, {
@@ -924,7 +925,7 @@ static int refdb_fs_backend__delete(
 	repo = backend->repo;
 
 	/* If a loose reference exists, remove it from the filesystem */
-	
+
 	if (git_buf_joinpath(&loose_path, repo->path_repository, ref->name) < 0)
 		return -1;
 
@@ -932,7 +933,7 @@ static int refdb_fs_backend__delete(
 		error = p_unlink(loose_path.ptr);
 		loose_deleted = 1;
 	}
-	
+
 	git_buf_free(&loose_path);
 
 	if (error != 0)
@@ -946,7 +947,7 @@ static int refdb_fs_backend__delete(
 
 		error = packed_write(backend);
 	}
-	
+
 	if (pack_error == GIT_ENOTFOUND)
 		error = loose_deleted ? 0 : GIT_ENOTFOUND;
 	else
diff --git a/src/refs.c b/src/refs.c
index 5b5812a..9c6684a 100644
--- a/src/refs.c
+++ b/src/refs.c
@@ -19,7 +19,7 @@
 #include <git2/branch.h>
 #include <git2/refs.h>
 #include <git2/refdb.h>
-#include <git2/refdb_backend.h>
+#include <git2/sys/refs.h>
 
 GIT__USE_STRMAP;
 
@@ -45,8 +45,7 @@ static git_reference *alloc_ref(const char *name)
 }
 
 git_reference *git_reference__alloc_symbolic(
-	const char *name,
-	const char *target)
+	const char *name, const char *target)
 {
 	git_reference *ref;
 
@@ -255,10 +254,10 @@ int git_reference_lookup_resolved(
 		max_nesting = MAX_NESTING_LEVEL;
 	else if (max_nesting < 0)
 		max_nesting = DEFAULT_NESTING_LEVEL;
-	
+
 	strncpy(scan_name, name, GIT_REFNAME_MAX);
 	scan_type = GIT_REF_SYMBOLIC;
-	
+
 	if ((error = git_repository_refdb__weakptr(&refdb, repo)) < 0)
 		return -1;
 
@@ -276,7 +275,7 @@ int git_reference_lookup_resolved(
 
 		if ((error = git_refdb_lookup(&ref, refdb, scan_name)) < 0)
 			return error;
-		
+
 		scan_type = ref->type;
 	}
 
@@ -354,7 +353,7 @@ static int reference__create(
 	git_refdb *refdb;
 	git_reference *ref = NULL;
 	int error = 0;
-	
+
 	if (ref_out)
 		*ref_out = NULL;
 
@@ -369,7 +368,7 @@ static int reference__create(
 	} else {
 		ref = git_reference__alloc_symbolic(name, symbolic);
 	}
-	
+
 	GITERR_CHECK_ALLOC(ref);
 	ref->db = refdb;
 
@@ -377,7 +376,7 @@ static int reference__create(
 		git_reference_free(ref);
 		return error;
 	}
-	
+
 	if (ref_out == NULL)
 		git_reference_free(ref);
 	else
@@ -397,17 +396,17 @@ int git_reference_create(
 	int error = 0;
 
 	assert(repo && name && oid);
-	
+
 	/* Sanity check the reference being created - target must exist. */
 	if ((error = git_repository_odb__weakptr(&odb, repo)) < 0)
 		return error;
-	
+
 	if (!git_odb_exists(odb, oid)) {
 		giterr_set(GITERR_REFERENCE,
 			"Target OID for the reference doesn't exist on the repository");
 		return -1;
 	}
-	
+
 	return reference__create(ref_out, repo, name, oid, NULL, force);
 }
 
@@ -422,7 +421,7 @@ int git_reference_symbolic_create(
 	int error = 0;
 
 	assert(repo && name && target);
-	
+
 	if ((error = git_reference__normalize_name_lax(
 		normalized, sizeof(normalized), target)) < 0)
 		return error;
@@ -436,7 +435,7 @@ int git_reference_set_target(
 	const git_oid *id)
 {
 	assert(out && ref && id);
-	
+
 	if (ref->type != GIT_REF_OID) {
 		giterr_set(GITERR_REFERENCE, "Cannot set OID on symbolic reference");
 		return -1;
@@ -451,13 +450,13 @@ int git_reference_symbolic_set_target(
 	const char *target)
 {
 	assert(out && ref && target);
-	
+
 	if (ref->type != GIT_REF_SYMBOLIC) {
 		giterr_set(GITERR_REFERENCE,
 			"Cannot set symbolic target on a direct reference");
 		return -1;
 	}
-	
+
 	return git_reference_symbolic_create(out, ref->db->repo, ref->name, target, 1);
 }
 
@@ -473,7 +472,7 @@ int git_reference_rename(
 	git_reference *result = NULL;
 	int error = 0;
 	int reference_has_log;
-	
+
 	*out = NULL;
 
 	normalization_flags = ref->type == GIT_REF_SYMBOLIC ?
@@ -488,7 +487,7 @@ int git_reference_rename(
 	 * Create the new reference.
 	 */
 	if (ref->type == GIT_REF_OID) {
-		result = git_reference__alloc(new_name, &ref->target.oid, &ref->peel); 
+		result = git_reference__alloc(new_name, &ref->target.oid, &ref->peel);
 	} else if (ref->type == GIT_REF_SYMBOLIC) {
 		result = git_reference__alloc_symbolic(new_name, ref->target.symbolic);
 	} else {
@@ -509,11 +508,11 @@ int git_reference_rename(
 	/* Now delete the old ref and save the new one. */
 	if ((error = git_refdb_delete(ref->db, ref)) < 0)
 		goto on_error;
-	
+
 	/* Save the new reference. */
 	if ((error = git_refdb_write(ref->db, result)) < 0)
 		goto rollback;
-	
+
 	/* Update HEAD it was poiting to the reference being renamed. */
 	if (should_head_be_updated && (error = git_repository_set_head(ref->db->repo, new_name)) < 0) {
 		giterr_set(GITERR_REFERENCE, "Failed to update HEAD after renaming reference");
@@ -547,7 +546,7 @@ int git_reference_resolve(git_reference **ref_out, const git_reference *ref)
 	switch (git_reference_type(ref)) {
 	case GIT_REF_OID:
 		return git_reference_lookup(ref_out, ref->db->repo, ref->name);
-	
+
 	case GIT_REF_SYMBOLIC:
 		return git_reference_lookup_resolved(ref_out, ref->db->repo, ref->target.symbolic, -1);
 
@@ -846,7 +845,7 @@ static int reference__update_terminal(
 
 	if (nesting > MAX_NESTING_LEVEL)
 		return GIT_ENOTFOUND;
-	
+
 	error = git_reference_lookup(&ref, repo, ref_name);
 
 	/* If we haven't found the reference at all, create a new reference. */
@@ -854,10 +853,10 @@ static int reference__update_terminal(
 		giterr_clear();
 		return git_reference_create(NULL, repo, ref_name, oid, 0);
 	}
-	
+
 	if (error < 0)
 		return error;
-	
+
 	/* If the ref is a symbolic reference, follow its target. */
 	if (git_reference_type(ref) == GIT_REF_SYMBOLIC) {
 		error = reference__update_terminal(repo, git_reference_symbolic_target(ref), oid,
@@ -867,7 +866,7 @@ static int reference__update_terminal(
 		git_reference_free(ref);
 		error = git_reference_create(NULL, repo, ref_name, oid, 1);
 	}
-	
+
 	return error;
 }
 
diff --git a/src/repository.c b/src/repository.c
index 64ab2f4..a16f69d 100644
--- a/src/repository.c
+++ b/src/repository.c
@@ -9,6 +9,7 @@
 
 #include "git2/object.h"
 #include "git2/refdb.h"
+#include "git2/sys/repository.h"
 
 #include "common.h"
 #include "repository.h"
@@ -129,6 +130,12 @@ static git_repository *repository_alloc(void)
 	return repo;
 }
 
+int git_repository_new(git_repository **out)
+{
+	*out = repository_alloc();
+	return 0;
+}
+
 static int load_config_data(git_repository *repo)
 {
 	int is_bare;
diff --git a/src/submodule.c b/src/submodule.c
index 2fdaf2f..0a22e3b 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -7,6 +7,7 @@
 
 #include "common.h"
 #include "git2/config.h"
+#include "git2/sys/config.h"
 #include "git2/types.h"
 #include "git2/repository.h"
 #include "git2/index.h"
diff --git a/src/tag.c b/src/tag.c
index 735ba7e..c82decb 100644
--- a/src/tag.c
+++ b/src/tag.c
@@ -13,6 +13,7 @@
 #include "git2/object.h"
 #include "git2/repository.h"
 #include "git2/signature.h"
+#include "git2/odb_backend.h"
 
 void git_tag__free(git_tag *tag)
 {
diff --git a/src/transports/smart_protocol.c b/src/transports/smart_protocol.c
index 8acedeb..9085198 100644
--- a/src/transports/smart_protocol.c
+++ b/src/transports/smart_protocol.c
@@ -5,6 +5,7 @@
  * a Linking Exception. For full terms see the included COPYING file.
  */
 #include "git2.h"
+#include "git2/odb_backend.h"
 
 #include "smart.h"
 #include "refs.h"
diff --git a/src/util.h b/src/util.h
index c0f2719..af3ef0b 100644
--- a/src/util.h
+++ b/src/util.h
@@ -7,6 +7,8 @@
 #ifndef INCLUDE_util_h__
 #define INCLUDE_util_h__
 
+#include "common.h"
+
 #define ARRAY_SIZE(x) (sizeof(x)/sizeof(x[0]))
 #define bitsizeof(x) (CHAR_BIT * sizeof(x))
 #define MSB(x, bits) ((x) & (~0ULL << (bitsizeof(x) - (bits))))
diff --git a/tests-clar/config/backend.c b/tests-clar/config/backend.c
index 28502a8..3fd6eb1 100644
--- a/tests-clar/config/backend.c
+++ b/tests-clar/config/backend.c
@@ -1,4 +1,5 @@
 #include "clar_libgit2.h"
+#include "git2/sys/config.h"
 
 void test_config_backend__checks_version(void)
 {
diff --git a/tests-clar/diff/patch.c b/tests-clar/diff/patch.c
index 4d17da4..d41f3f1 100644
--- a/tests-clar/diff/patch.c
+++ b/tests-clar/diff/patch.c
@@ -1,4 +1,6 @@
 #include "clar_libgit2.h"
+#include "git2/sys/repository.h"
+
 #include "diff_helpers.h"
 #include "repository.h"
 #include "buf_text.h"
diff --git a/tests-clar/object/raw/write.c b/tests-clar/object/raw/write.c
index 1b28d0d..60aa31f 100644
--- a/tests-clar/object/raw/write.c
+++ b/tests-clar/object/raw/write.c
@@ -1,5 +1,6 @@
-
 #include "clar_libgit2.h"
+#include "git2/odb_backend.h"
+
 #include "fileops.h"
 #include "odb.h"
 
diff --git a/tests-clar/odb/packed_one.c b/tests-clar/odb/packed_one.c
index e9d246c..4f9bde9 100644
--- a/tests-clar/odb/packed_one.c
+++ b/tests-clar/odb/packed_one.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
-#include "odb.h"
+#include "git2/odb_backend.h"
+
 #include "pack_data_one.h"
 #include "pack.h"
 
diff --git a/tests-clar/odb/sorting.c b/tests-clar/odb/sorting.c
index b4f9e44..147a160 100644
--- a/tests-clar/odb/sorting.c
+++ b/tests-clar/odb/sorting.c
@@ -1,13 +1,12 @@
 #include "clar_libgit2.h"
-#include "git2/odb_backend.h"
-#include "odb.h"
+#include "git2/sys/odb_backend.h"
 
 typedef struct {
 	git_odb_backend base;
-	int position;
+	size_t position;
 } fake_backend;
 
-static git_odb_backend *new_backend(int position)
+static git_odb_backend *new_backend(size_t position)
 {
 	fake_backend *b;
 
@@ -22,14 +21,13 @@ static git_odb_backend *new_backend(int position)
 
 static void check_backend_sorting(git_odb *odb)
 {
-	unsigned int i;
-
-	for (i = 0; i < odb->backends.length; ++i) {
-		fake_backend *internal =
-			*((fake_backend **)git_vector_get(&odb->backends, i));
+	size_t i, max_i = git_odb_num_backends(odb);
+	fake_backend *internal;
 
+	for (i = 0; i < max_i; ++i) {
+		cl_git_pass(git_odb_get_backend((git_odb_backend **)&internal, odb, i));
 		cl_assert(internal != NULL);
-		cl_assert(internal->position == (int)i);
+		cl_assert_equal_sz(i, internal->position);
 	}
 }
 
diff --git a/tests-clar/refdb/inmemory.c b/tests-clar/refdb/inmemory.c
index ea76172..243b5bb 100644
--- a/tests-clar/refdb/inmemory.c
+++ b/tests-clar/refdb/inmemory.c
@@ -1,12 +1,15 @@
 #include "clar_libgit2.h"
-#include "refdb.h"
-#include "repository.h"
+
+#include "buffer.h"
+#include "posix.h"
+#include "path.h"
+#include "refs.h"
+
 #include "testdb.h"
 
 #define TEST_REPO_PATH "testrepo"
 
 static git_repository *repo;
-static git_refdb_backend *refdb_backend;
 
 int unlink_ref(void *payload, git_buf *file)
 {
@@ -26,7 +29,7 @@ int ref_file_foreach(git_repository *repo, int (* cb)(void *payload, git_buf *fi
 	const char *repo_path;
 	git_buf repo_refs_dir = GIT_BUF_INIT;
 	int error = 0;
-	
+
 	repo_path = git_repository_path(repo);
 
 	git_buf_joinpath(&repo_refs_dir, repo_path, "HEAD");
@@ -38,7 +41,7 @@ int ref_file_foreach(git_repository *repo, int (* cb)(void *payload, git_buf *fi
 	git_buf_joinpath(&repo_refs_dir, git_buf_cstr(&repo_refs_dir), "heads");
 	if (git_path_direach(&repo_refs_dir, cb, NULL) != 0)
 		return -1;
-	
+
 	git_buf_joinpath(&repo_refs_dir, repo_path, "packed-refs");
 	if (git_path_exists(git_buf_cstr(&repo_refs_dir)) &&
 		cb(NULL, &repo_refs_dir) < 0)
@@ -51,16 +54,16 @@ int ref_file_foreach(git_repository *repo, int (* cb)(void *payload, git_buf *fi
 
 void test_refdb_inmemory__initialize(void)
 {
-	git_refdb *refdb;
-
 	git_buf repo_refs_dir = GIT_BUF_INIT;
+	git_refdb *refdb;
+	git_refdb_backend *refdb_backend;
 
 	repo = cl_git_sandbox_init(TEST_REPO_PATH);
 
 	cl_git_pass(git_repository_refdb(&refdb, repo));
 	cl_git_pass(refdb_backend_test(&refdb_backend, repo));
 	cl_git_pass(git_refdb_set_backend(refdb, refdb_backend));
-	
+
 	ref_file_foreach(repo, unlink_ref);
 
 	git_buf_free(&repo_refs_dir);
@@ -76,10 +79,10 @@ void test_refdb_inmemory__doesnt_write_ref_file(void)
 {
 	git_reference *ref;
 	git_oid oid;
-	
+
 	cl_git_pass(git_oid_fromstr(&oid, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
 	cl_git_pass(git_reference_create(&ref, repo, GIT_REFS_HEADS_DIR "test1", &oid, 0));
-	
+
 	ref_file_foreach(repo, empty);
 
 	git_reference_free(ref);
@@ -89,10 +92,10 @@ void test_refdb_inmemory__read(void)
 {
 	git_reference *write1, *write2, *write3, *read1, *read2, *read3;
 	git_oid oid1, oid2, oid3;
-	
+
 	cl_git_pass(git_oid_fromstr(&oid1, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
 	cl_git_pass(git_reference_create(&write1, repo, GIT_REFS_HEADS_DIR "test1", &oid1, 0));
-	
+
 	cl_git_pass(git_oid_fromstr(&oid2, "e90810b8df3e80c413d903f631643c716887138d"));
 	cl_git_pass(git_reference_create(&write2, repo, GIT_REFS_HEADS_DIR "test2", &oid2, 0));
 
@@ -139,7 +142,7 @@ int foreach_test(const char *ref_name, void *payload)
 	cl_assert(git_oid_cmp(&expected, git_reference_target(ref)) == 0);
 
 	++(*i);
-	
+
 	git_reference_free(ref);
 
 	return 0;
@@ -150,19 +153,19 @@ void test_refdb_inmemory__foreach(void)
 	git_reference *write1, *write2, *write3;
 	git_oid oid1, oid2, oid3;
 	size_t i = 0;
-	
+
 	cl_git_pass(git_oid_fromstr(&oid1, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
 	cl_git_pass(git_reference_create(&write1, repo, GIT_REFS_HEADS_DIR "test1", &oid1, 0));
-	
+
 	cl_git_pass(git_oid_fromstr(&oid2, "e90810b8df3e80c413d903f631643c716887138d"));
 	cl_git_pass(git_reference_create(&write2, repo, GIT_REFS_HEADS_DIR "test2", &oid2, 0));
-	
+
 	cl_git_pass(git_oid_fromstr(&oid3, "763d71aadf09a7951596c9746c024e7eece7c7af"));
 	cl_git_pass(git_reference_create(&write3, repo, GIT_REFS_HEADS_DIR "test3", &oid3, 0));
-	
+
 	cl_git_pass(git_reference_foreach(repo, GIT_REF_LISTALL, foreach_test, &i));
 	cl_assert_equal_i(3, (int)i);
-	
+
 	git_reference_free(write1);
 	git_reference_free(write2);
 	git_reference_free(write3);
@@ -175,14 +178,14 @@ int delete_test(const char *ref_name, void *payload)
 	size_t *i = payload;
 
 	cl_git_pass(git_reference_lookup(&ref, repo, ref_name));
-	
-	cl_git_pass(git_oid_fromstr(&expected, "e90810b8df3e80c413d903f631643c716887138d"));	
+
+	cl_git_pass(git_oid_fromstr(&expected, "e90810b8df3e80c413d903f631643c716887138d"));
 	cl_assert(git_oid_cmp(&expected, git_reference_target(ref)) == 0);
-	
+
 	++(*i);
-	
+
 	git_reference_free(ref);
-	
+
 	return 0;
 }
 
@@ -191,22 +194,22 @@ void test_refdb_inmemory__delete(void)
 	git_reference *write1, *write2, *write3;
 	git_oid oid1, oid2, oid3;
 	size_t i = 0;
-	
+
 	cl_git_pass(git_oid_fromstr(&oid1, "c47800c7266a2be04c571c04d5a6614691ea99bd"));
 	cl_git_pass(git_reference_create(&write1, repo, GIT_REFS_HEADS_DIR "test1", &oid1, 0));
-	
+
 	cl_git_pass(git_oid_fromstr(&oid2, "e90810b8df3e80c413d903f631643c716887138d"));
 	cl_git_pass(git_reference_create(&write2, repo, GIT_REFS_HEADS_DIR "test2", &oid2, 0));
-	
+
 	cl_git_pass(git_oid_fromstr(&oid3, "763d71aadf09a7951596c9746c024e7eece7c7af"));
 	cl_git_pass(git_reference_create(&write3, repo, GIT_REFS_HEADS_DIR "test3", &oid3, 0));
-	
+
 	git_reference_delete(write1);
 	git_reference_free(write1);
-	
+
 	git_reference_delete(write3);
 	git_reference_free(write3);
-	
+
 	cl_git_pass(git_reference_foreach(repo, GIT_REF_LISTALL, delete_test, &i));
 	cl_assert_equal_i(1, (int)i);
 
diff --git a/tests-clar/refdb/testdb.c b/tests-clar/refdb/testdb.c
index 4bca398..627254e 100644
--- a/tests-clar/refdb/testdb.c
+++ b/tests-clar/refdb/testdb.c
@@ -1,14 +1,10 @@
-#include "common.h"
 #include "vector.h"
 #include "util.h"
-#include <git2/refdb.h>
-#include <git2/refdb_backend.h>
-#include <git2/errors.h>
-#include <git2/repository.h>
+#include "testdb.h"
 
 typedef struct refdb_test_backend {
 	git_refdb_backend parent;
-	
+
 	git_repository *repo;
 	git_vector refs;
 } refdb_test_backend;
@@ -16,7 +12,7 @@ typedef struct refdb_test_backend {
 typedef struct refdb_test_entry {
 	char *name;
 	git_ref_t type;
-	
+
 	union {
 		git_oid oid;
 		char *symbolic;
@@ -37,19 +33,19 @@ static int refdb_test_backend__exists(
 	refdb_test_backend *backend;
 	refdb_test_entry *entry;
 	size_t i;
-	
+
 	assert(_backend);
 	backend = (refdb_test_backend *)_backend;
-	
+
 	*exists = 0;
-	
+
 	git_vector_foreach(&backend->refs, i, entry) {
 		if (strcmp(entry->name, ref_name) == 0) {
 			*exists = 1;
 			break;
 		}
 	}
-	
+
 	return 0;
 }
 
@@ -59,18 +55,18 @@ static int refdb_test_backend__write(
 {
 	refdb_test_backend *backend;
 	refdb_test_entry *entry;
-	
+
 	assert(_backend);
 	backend = (refdb_test_backend *)_backend;
 
 	entry = git__calloc(1, sizeof(refdb_test_entry));
 	GITERR_CHECK_ALLOC(entry);
-	
+
 	entry->name = git__strdup(git_reference_name(ref));
 	GITERR_CHECK_ALLOC(entry->name);
-	
+
 	entry->type = git_reference_type(ref);
-	
+
 	if (entry->type == GIT_REF_OID)
 		git_oid_cpy(&entry->target.oid, git_reference_target(ref));
 	else {
@@ -79,7 +75,7 @@ static int refdb_test_backend__write(
 	}
 
 	git_vector_insert(&backend->refs, entry);
-	
+
 	return 0;
 }
 
@@ -94,7 +90,7 @@ static int refdb_test_backend__lookup(
 
 	assert(_backend);
 	backend = (refdb_test_backend *)_backend;
-	
+
 	git_vector_foreach(&backend->refs, i, entry) {
 		if (strcmp(entry->name, ref_name) == 0) {
 
@@ -108,7 +104,7 @@ static int refdb_test_backend__lookup(
 
 			if (*out == NULL)
 				return -1;
-			
+
 			return 0;
 		}
 	}
@@ -125,21 +121,21 @@ static int refdb_test_backend__foreach(
 	refdb_test_backend *backend;
 	refdb_test_entry *entry;
 	size_t i;
-	
+
 	assert(_backend);
 	backend = (refdb_test_backend *)_backend;
 
 	git_vector_foreach(&backend->refs, i, entry) {
 		if (entry->type == GIT_REF_OID && (list_flags & GIT_REF_OID) == 0)
 			continue;
-		
+
 		if (entry->type == GIT_REF_SYMBOLIC && (list_flags & GIT_REF_SYMBOLIC) == 0)
 			continue;
-		
+
 		if (callback(entry->name, payload) != 0)
 			return GIT_EUSER;
 	}
-	
+
 	return 0;
 }
 
@@ -147,7 +143,7 @@ static void refdb_test_entry_free(refdb_test_entry *entry)
 {
 	if (entry->type == GIT_REF_SYMBOLIC)
 		git__free(entry->target.symbolic);
-	
+
 	git__free(entry->name);
 	git__free(entry);
 }
@@ -178,14 +174,14 @@ static void refdb_test_backend__free(git_refdb_backend *_backend)
 	refdb_test_backend *backend;
 	refdb_test_entry *entry;
 	size_t i;
-	
+
 	assert(_backend);
 	backend = (refdb_test_backend *)_backend;
 
 	git_vector_foreach(&backend->refs, i, entry)
 		refdb_test_entry_free(entry);
 
-	git_vector_free(&backend->refs);	
+	git_vector_free(&backend->refs);
 	git__free(backend);
 }
 
@@ -197,7 +193,7 @@ int refdb_backend_test(
 
 	backend = git__calloc(1, sizeof(refdb_test_backend));
 	GITERR_CHECK_ALLOC(backend);
-	
+
 	git_vector_init(&backend->refs, 0, ref_name_cmp);
 
 	backend->repo = repo;
diff --git a/tests-clar/refdb/testdb.h b/tests-clar/refdb/testdb.h
index e38abd9..a0d1bbc 100644
--- a/tests-clar/refdb/testdb.h
+++ b/tests-clar/refdb/testdb.h
@@ -1,3 +1,9 @@
+#include <git2/errors.h>
+#include <git2/repository.h>
+#include <git2/refdb.h>
+#include <git2/sys/refs.h>
+#include <git2/sys/refdb_backend.h>
+
 int refdb_backend_test(
 	git_refdb_backend **backend_out,
 	git_repository *repo);
diff --git a/tests-clar/repo/setters.c b/tests-clar/repo/setters.c
index 7e482de..063d76c 100644
--- a/tests-clar/repo/setters.c
+++ b/tests-clar/repo/setters.c
@@ -1,4 +1,6 @@
 #include "clar_libgit2.h"
+#include "git2/sys/repository.h"
+
 #include "buffer.h"
 #include "posix.h"
 #include "util.h"
diff --git a/tests-clar/status/worktree_init.c b/tests-clar/status/worktree_init.c
index b67107a..296c27c 100644
--- a/tests-clar/status/worktree_init.c
+++ b/tests-clar/status/worktree_init.c
@@ -1,4 +1,6 @@
 #include "clar_libgit2.h"
+#include "git2/sys/repository.h"
+
 #include "fileops.h"
 #include "ignore.h"
 #include "status_helpers.h"
@@ -321,10 +323,10 @@ void test_status_worktree_init__new_staged_file_must_handle_crlf(void)
 	cl_set_cleanup(&cleanup_new_repo, "getting_started");
 	cl_git_pass(git_repository_init(&repo, "getting_started", 0));
 
-	// Ensure that repo has core.autocrlf=true
+	/* Ensure that repo has core.autocrlf=true */
 	cl_repo_set_bool(repo, "core.autocrlf", true);
 
-	cl_git_mkfile("getting_started/testfile.txt", "content\r\n");	// Content with CRLF
+	cl_git_mkfile("getting_started/testfile.txt", "content\r\n");	/* Content with CRLF */
 
 	cl_git_pass(git_repository_index(&index, repo));
 	cl_git_pass(git_index_add_bypath(index, "testfile.txt"));