thodg/libgit2

diff --git a/include/git2/index.h b/include/git2/index.h
index 01e3d2c..d23c3a8 100644
--- a/include/git2/index.h
+++ b/include/git2/index.h
@@ -84,19 +84,6 @@ typedef struct git_index_entry {
 	char *path;
 } git_index_entry;
 
-typedef struct git_index_name_entry {
-	char *ancestor;
-	char *ours;
-	char *theirs;
-} git_index_name_entry;
-
-/** Representation of a resolve undo entry in the index. */
-typedef struct git_index_reuc_entry {
-	unsigned int mode[3];
-	git_oid oid[3];
-	char *path;
-} git_index_reuc_entry;
-
 /** Capabilities of system that affect index actions. */
 enum {
 	GIT_INDEXCAP_IGNORE_CASE = 1,
@@ -484,149 +471,6 @@ GIT_EXTERN(int) git_index_has_conflicts(const git_index *index);
 
 /**@}*/
 
-/** @name Conflict Name entry functions
- *
- * These functions work on rename conflict entries.
- */
-/**@{*/
-
-/**
- * Get the count of filename conflict entries currently in the index.
- *
- * @param index an existing index object
- * @return integer of count of current filename conflict entries
- */
-GIT_EXTERN(unsigned int) git_index_name_entrycount(git_index *index);
-
-/**
- * Get a filename conflict entry from the index.
- *
- * The returned entry is read-only and should not be modified
- * or freed by the caller.
- *
- * @param index an existing index object
- * @param n the position of the entry
- * @return a pointer to the filename conflict entry; NULL if out of bounds
- */
-GIT_EXTERN(const git_index_name_entry *) git_index_name_get_byindex(
-	git_index *index, size_t n);
-
-/**
- * Record the filenames involved in a rename conflict.
- *
- * @param index an existing index object
- * @param ancestor the path of the file as it existed in the ancestor
- * @param ours the path of the file as it existed in our tree
- * @param theirs the path of the file as it existed in their tree
- */
-GIT_EXTERN(int) git_index_name_add(git_index *index,
-	const char *ancestor, const char *ours, const char *theirs);
-
-/**
- * Remove all filename conflict entries.
- *
- * @param index an existing index object
- * @return 0 or an error code
- */
-GIT_EXTERN(void) git_index_name_clear(git_index *index);
-/**@}*/
-
-/** @name Resolve Undo (REUC) index entry manipulation.
- *
- * These functions work on the Resolve Undo index extension and contains
- * data about the original files that led to a merge conflict.
- */
-/**@{*/
-
-/**
- * Get the count of resolve undo entries currently in the index.
- *
- * @param index an existing index object
- * @return integer of count of current resolve undo entries
- */
-GIT_EXTERN(unsigned int) git_index_reuc_entrycount(git_index *index);
-
-/**
- * Finds the resolve undo entry that points to the given path in the Git
- * index.
- *
- * @param at_pos the address to which the position of the reuc entry is written (optional)
- * @param index an existing index object
- * @param path path to search
- * @return 0 if found, < 0 otherwise (GIT_ENOTFOUND)
- */
-GIT_EXTERN(int) git_index_reuc_find(size_t *at_pos, git_index *index, const char *path);
-
-/**
- * Get a resolve undo entry from the index.
- *
- * The returned entry is read-only and should not be modified
- * or freed by the caller.
- *
- * @param index an existing index object
- * @param path path to search
- * @return the resolve undo entry; NULL if not found
- */
-GIT_EXTERN(const git_index_reuc_entry *) git_index_reuc_get_bypath(git_index *index, const char *path);
-
-/**
- * Get a resolve undo entry from the index.
- *
- * The returned entry is read-only and should not be modified
- * or freed by the caller.
- *
- * @param index an existing index object
- * @param n the position of the entry
- * @return a pointer to the resolve undo entry; NULL if out of bounds
- */
-GIT_EXTERN(const git_index_reuc_entry *) git_index_reuc_get_byindex(git_index *index, size_t n);
-
-/**
- * Adds a resolve undo entry for a file based on the given parameters.
- *
- * The resolve undo entry contains the OIDs of files that were involved
- * in a merge conflict after the conflict has been resolved.  This allows
- * conflicts to be re-resolved later.
- *
- * If there exists a resolve undo entry for the given path in the index,
- * it will be removed.
- *
- * This method will fail in bare index instances.
- *
- * @param index an existing index object
- * @param path filename to add
- * @param ancestor_mode mode of the ancestor file
- * @param ancestor_id oid of the ancestor file
- * @param our_mode mode of our file
- * @param our_id oid of our file
- * @param their_mode mode of their file
- * @param their_id oid of their file
- * @return 0 or an error code
- */
-GIT_EXTERN(int) git_index_reuc_add(git_index *index, const char *path,
-	int ancestor_mode, const git_oid *ancestor_id,
-	int our_mode, const git_oid *our_id,
-	int their_mode, const git_oid *their_id);
-
-/**
- * Remove an resolve undo entry from the index
- *
- * @param index an existing index object
- * @param n position of the resolve undo entry to remove
- * @return 0 or an error code
- */
-GIT_EXTERN(int) git_index_reuc_remove(git_index *index, size_t n);
-
-/**
- * Remove all resolve undo entries from the index
- *
- * @param index an existing index object
- * @return 0 or an error code
- */
-GIT_EXTERN(void) git_index_reuc_clear(git_index *index);
-
-/**@}*/
-
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/include/git2/sys/index.h b/include/git2/sys/index.h
new file mode 100644
index 0000000..f74637f
--- /dev/null
+++ b/include/git2/sys/index.h
@@ -0,0 +1,180 @@
+/*
+ * 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_index_h__
+#define INCLUDE_sys_git_index_h__
+
+/**
+ * @file git2/sys/index.h
+ * @brief Low-level Git index manipulation routines
+ * @defgroup git_backend Git custom backend APIs
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/** Representation of a rename conflict entry in the index. */
+typedef struct git_index_name_entry {
+	char *ancestor;
+	char *ours;
+	char *theirs;
+} git_index_name_entry;
+
+/** Representation of a resolve undo entry in the index. */
+typedef struct git_index_reuc_entry {
+	unsigned int mode[3];
+	git_oid oid[3];
+	char *path;
+} git_index_reuc_entry;
+
+/** @name Conflict Name entry functions
+ *
+ * These functions work on rename conflict entries.
+ */
+/**@{*/
+
+/**
+ * Get the count of filename conflict entries currently in the index.
+ *
+ * @param index an existing index object
+ * @return integer of count of current filename conflict entries
+ */
+GIT_EXTERN(unsigned int) git_index_name_entrycount(git_index *index);
+
+/**
+ * Get a filename conflict entry from the index.
+ *
+ * The returned entry is read-only and should not be modified
+ * or freed by the caller.
+ *
+ * @param index an existing index object
+ * @param n the position of the entry
+ * @return a pointer to the filename conflict entry; NULL if out of bounds
+ */
+GIT_EXTERN(const git_index_name_entry *) git_index_name_get_byindex(
+	git_index *index, size_t n);
+
+/**
+ * Record the filenames involved in a rename conflict.
+ *
+ * @param index an existing index object
+ * @param ancestor the path of the file as it existed in the ancestor
+ * @param ours the path of the file as it existed in our tree
+ * @param theirs the path of the file as it existed in their tree
+ */
+GIT_EXTERN(int) git_index_name_add(git_index *index,
+	const char *ancestor, const char *ours, const char *theirs);
+
+/**
+ * Remove all filename conflict entries.
+ *
+ * @param index an existing index object
+ * @return 0 or an error code
+ */
+GIT_EXTERN(void) git_index_name_clear(git_index *index);
+
+/**@}*/
+
+/** @name Resolve Undo (REUC) index entry manipulation.
+ *
+ * These functions work on the Resolve Undo index extension and contains
+ * data about the original files that led to a merge conflict.
+ */
+/**@{*/
+
+/**
+ * Get the count of resolve undo entries currently in the index.
+ *
+ * @param index an existing index object
+ * @return integer of count of current resolve undo entries
+ */
+GIT_EXTERN(unsigned int) git_index_reuc_entrycount(git_index *index);
+
+/**
+ * Finds the resolve undo entry that points to the given path in the Git
+ * index.
+ *
+ * @param at_pos the address to which the position of the reuc entry is written (optional)
+ * @param index an existing index object
+ * @param path path to search
+ * @return 0 if found, < 0 otherwise (GIT_ENOTFOUND)
+ */
+GIT_EXTERN(int) git_index_reuc_find(size_t *at_pos, git_index *index, const char *path);
+
+/**
+ * Get a resolve undo entry from the index.
+ *
+ * The returned entry is read-only and should not be modified
+ * or freed by the caller.
+ *
+ * @param index an existing index object
+ * @param path path to search
+ * @return the resolve undo entry; NULL if not found
+ */
+GIT_EXTERN(const git_index_reuc_entry *) git_index_reuc_get_bypath(git_index *index, const char *path);
+
+/**
+ * Get a resolve undo entry from the index.
+ *
+ * The returned entry is read-only and should not be modified
+ * or freed by the caller.
+ *
+ * @param index an existing index object
+ * @param n the position of the entry
+ * @return a pointer to the resolve undo entry; NULL if out of bounds
+ */
+GIT_EXTERN(const git_index_reuc_entry *) git_index_reuc_get_byindex(git_index *index, size_t n);
+
+/**
+ * Adds a resolve undo entry for a file based on the given parameters.
+ *
+ * The resolve undo entry contains the OIDs of files that were involved
+ * in a merge conflict after the conflict has been resolved.  This allows
+ * conflicts to be re-resolved later.
+ *
+ * If there exists a resolve undo entry for the given path in the index,
+ * it will be removed.
+ *
+ * This method will fail in bare index instances.
+ *
+ * @param index an existing index object
+ * @param path filename to add
+ * @param ancestor_mode mode of the ancestor file
+ * @param ancestor_id oid of the ancestor file
+ * @param our_mode mode of our file
+ * @param our_id oid of our file
+ * @param their_mode mode of their file
+ * @param their_id oid of their file
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_index_reuc_add(git_index *index, const char *path,
+	int ancestor_mode, const git_oid *ancestor_id,
+	int our_mode, const git_oid *our_id,
+	int their_mode, const git_oid *their_id);
+
+/**
+ * Remove an resolve undo entry from the index
+ *
+ * @param index an existing index object
+ * @param n position of the resolve undo entry to remove
+ * @return 0 or an error code
+ */
+GIT_EXTERN(int) git_index_reuc_remove(git_index *index, size_t n);
+
+/**
+ * Remove all resolve undo entries from the index
+ *
+ * @param index an existing index object
+ * @return 0 or an error code
+ */
+GIT_EXTERN(void) git_index_reuc_clear(git_index *index);
+
+/**@}*/
+
+/** @} */
+GIT_END_DECL
+#endif
+
diff --git a/src/index.c b/src/index.c
index 656fb5b..a935c00 100644
--- a/src/index.c
+++ b/src/index.c
@@ -19,6 +19,7 @@
 #include "git2/oid.h"
 #include "git2/blob.h"
 #include "git2/config.h"
+#include "git2/sys/index.h"
 
 #define entry_size(type,len) ((offsetof(type, path) + (len) + 8) & ~7)
 #define short_entry_size(len) entry_size(struct entry_short, len)
diff --git a/src/merge.c b/src/merge.c
index 681f302..3595eb0 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -36,6 +36,7 @@
 #include "git2/signature.h"
 #include "git2/config.h"
 #include "git2/tree.h"
+#include "git2/sys/index.h"
 
 #define GIT_MERGE_INDEX_ENTRY_EXISTS(X)	((X).mode != 0)
 
diff --git a/tests-clar/index/names.c b/tests-clar/index/names.c
index ffc9842..6861553 100644
--- a/tests-clar/index/names.c
+++ b/tests-clar/index/names.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "index.h"
+#include "git2/sys/index.h"
 #include "git2/repository.h"
 #include "../reset/reset_helpers.h"
 
diff --git a/tests-clar/index/reuc.c b/tests-clar/index/reuc.c
index 4d5955a..0e38a92 100644
--- a/tests-clar/index/reuc.c
+++ b/tests-clar/index/reuc.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include "index.h"
+#include "git2/sys/index.h"
 #include "git2/repository.h"
 #include "../reset/reset_helpers.h"
 
diff --git a/tests-clar/merge/merge_helpers.c b/tests-clar/merge/merge_helpers.c
index 7cb1e53..b2c70be 100644
--- a/tests-clar/merge/merge_helpers.c
+++ b/tests-clar/merge/merge_helpers.c
@@ -5,6 +5,7 @@
 #include "merge_helpers.h"
 #include "merge.h"
 #include "git2/merge.h"
+#include "git2/sys/index.h"
 
 int merge_trees_from_branches(
 	git_index **index, git_repository *repo,
diff --git a/tests-clar/merge/trees/trivial.c b/tests-clar/merge/trees/trivial.c
index 54b07e7..7d8d2cb 100644
--- a/tests-clar/merge/trees/trivial.c
+++ b/tests-clar/merge/trees/trivial.c
@@ -5,6 +5,7 @@
 #include "../merge_helpers.h"
 #include "refs.h"
 #include "fileops.h"
+#include "git2/sys/index.h"
 
 static git_repository *repo;