thodg/libgit2

diff --git a/include/git2.h b/include/git2.h
index 501128c..36f2416 100644
--- a/include/git2.h
+++ b/include/git2.h
@@ -23,6 +23,7 @@
 #include "git2/repository.h"
 #include "git2/revwalk.h"
 #include "git2/merge.h"
+#include "git2/graph.h"
 #include "git2/refs.h"
 #include "git2/reflog.h"
 #include "git2/revparse.h"
diff --git a/include/git2/graph.h b/include/git2/graph.h
new file mode 100644
index 0000000..c89efa6
--- /dev/null
+++ b/include/git2/graph.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * 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_graph_h__
+#define INCLUDE_git_graph_h__
+
+#include "common.h"
+#include "types.h"
+#include "oid.h"
+
+/**
+ * @file git2/graph.h
+ * @brief Git graph traversal routines
+ * @defgroup git_revwalk Git graph traversal routines
+ * @ingroup Git
+ * @{
+ */
+GIT_BEGIN_DECL
+
+/**
+ * Count the number of unique commits between two commit objects
+ *
+ * @param ahead number of commits, starting at `one`, unique from commits in `two`
+ * @param behind number of commits, starting at `two`, unique from commits in `one`
+ * @param repo the repository where the commits exist
+ * @param one one of the commits
+ * @param two the other commit
+ */
+GIT_EXTERN(int) git_graph_ahead_behind(size_t *ahead, size_t *behind, git_repository *repo, const git_oid *one, const git_oid *two);
+
+/** @} */
+GIT_END_DECL
+#endif
diff --git a/include/git2/merge.h b/include/git2/merge.h
index 928c475..5949396 100644
--- a/include/git2/merge.h
+++ b/include/git2/merge.h
@@ -50,17 +50,6 @@ GIT_EXTERN(int) git_merge_base_many(
 	const git_oid input_array[],
 	size_t length);
 
-/**
- * Count the number of unique commits between two commit objects
- *
- * @param ahead number of commits, starting at `one`, unique from commits in `two` 
- * @param behind number of commits, starting at `two`, unique from commits in `one`
- * @param repo the repository where the commits exist
- * @param one one of the commits
- * @param two the other commit
- */
-GIT_EXTERN(int) git_count_ahead_behind(int *ahead, int *behind, git_repository *repo, git_oid *one, git_oid *two);
-
 /** @} */
 GIT_END_DECL
 #endif
diff --git a/src/graph.c b/src/graph.c
new file mode 100644
index 0000000..db4d730
--- /dev/null
+++ b/src/graph.c
@@ -0,0 +1,100 @@
+
+/*
+ * Copyright (C) 2009-2012 the libgit2 contributors
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "repository.h"
+#include "revwalk.h"
+#include "buffer.h"
+#include "merge.h"
+#include "refs.h"
+#include "git2/repository.h"
+#include "git2/merge.h"
+#include "git2/reset.h"
+#include "commit_list.h"
+#include "git2/graph.h"
+
+static int ahead_behind(git_commit_list_node *one, git_commit_list_node *two,
+	size_t *ahead, size_t *behind)
+{
+	git_commit_list_node *commit;
+	git_pqueue pq;
+	int i;
+	*ahead = 0;
+	*behind = 0;
+
+	if (git_pqueue_init(&pq, 2, git_commit_list_time_cmp) < 0)
+		return -1;
+	if (git_pqueue_insert(&pq, one) < 0)
+		return -1;
+	if (git_pqueue_insert(&pq, two) < 0)
+		return -1;
+
+	while ((commit = git_pqueue_pop(&pq)) != NULL) {
+		if (commit->flags & RESULT ||
+			(commit->flags & (PARENT1 | PARENT2)) == (PARENT1 | PARENT2))
+			continue;
+		else if (commit->flags & PARENT1)
+			(*behind)++;
+		else if (commit->flags & PARENT2)
+			(*ahead)++;
+
+		for (i = 0; i < commit->out_degree; i++) {
+			git_commit_list_node *p = commit->parents[i];
+			if (git_pqueue_insert(&pq, p) < 0)
+				return -1;
+		}
+		commit->flags |= RESULT;
+	}
+
+	return 0;
+}
+
+int git_graph_ahead_behind(size_t *ahead, size_t *behind, git_repository *repo,
+	const git_oid *one, const git_oid *two)
+{
+	git_revwalk *walk;
+	git_vector list;
+	struct git_commit_list *result = NULL;
+	git_commit_list_node *commit1, *commit2;
+	void *contents[1];
+
+	if (git_revwalk_new(&walk, repo) < 0)
+		return -1;
+
+	commit2 = commit_lookup(walk, two);
+	if (commit2 == NULL)
+		goto on_error;
+
+	/* This is just one value, so we can do it on the stack */
+	memset(&list, 0x0, sizeof(git_vector));
+	contents[0] = commit2;
+	list.length = 1;
+	list.contents = contents;
+
+	commit1 = commit_lookup(walk, one);
+	if (commit1 == NULL)
+		goto on_error;
+
+	if (git_merge__bases_many(&result, walk, commit1, &list) < 0)
+		goto on_error;
+	if (ahead_behind(commit1, commit2, ahead, behind) < 0)
+		goto on_error;
+
+	if (!result) {
+		git_revwalk_free(walk);
+		return GIT_ENOTFOUND;
+	}
+
+	git_commit_list_free(&result);
+	git_revwalk_free(walk);
+
+	return 0;
+
+on_error:
+	git_revwalk_free(walk);
+	return -1;
+}
diff --git a/src/merge.c b/src/merge.c
index 96d2168..323b7b8 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -241,85 +241,3 @@ int git_merge__bases_many(git_commit_list **out, git_revwalk *walk, git_commit_l
 	*out = result;
 	return 0;
 }
-
-static int count_ahead_behind(git_commit_list_node *one, git_commit_list_node *two,
-	int *ahead, int *behind)
-{
-	git_commit_list_node *commit;
-	git_pqueue pq;
-	int i;
-	*ahead = 0;
-	*behind = 0;
-
-	if (git_pqueue_init(&pq, 2, git_commit_list_time_cmp) < 0)
-		return -1;
-	if (git_pqueue_insert(&pq, one) < 0)
-		return -1;
-	if (git_pqueue_insert(&pq, two) < 0)
-		return -1;
-
-	while ((commit = git_pqueue_pop(&pq)) != NULL) {
-		if (commit->flags & RESULT ||
-			(commit->flags & (PARENT1 | PARENT2)) == (PARENT1 | PARENT2))
-			continue;
-		else if (commit->flags & PARENT1)
-			(*behind)++;
-		else if (commit->flags & PARENT2)
-			(*ahead)++;
-
-		for (i = 0; i < commit->out_degree; i++) {
-			git_commit_list_node *p = commit->parents[i];
-			if (git_pqueue_insert(&pq, p) < 0)
-				return -1;
-		}
-		commit->flags |= RESULT;
-	}
-
-	return 0;
-}
-
-int git_count_ahead_behind(int *ahead, int *behind, git_repository *repo, git_oid *one,
-	git_oid *two)
-{
-	git_revwalk *walk;
-	git_vector list;
-	struct git_commit_list *result = NULL;
-	git_commit_list_node *commit1, *commit2;
-	void *contents[1];
-
-	if (git_revwalk_new(&walk, repo) < 0)
-		return -1;
-
-	commit2 = commit_lookup(walk, two);
-	if (commit2 == NULL)
-		goto on_error;
-
-	/* This is just one value, so we can do it on the stack */
-	memset(&list, 0x0, sizeof(git_vector));
-	contents[0] = commit2;
-	list.length = 1;
-	list.contents = contents;
-
-	commit1 = commit_lookup(walk, one);
-	if (commit1 == NULL)
-		goto on_error;
-
-	if (git_merge__bases_many(&result, walk, commit1, &list) < 0)
-		goto on_error;
-	if (count_ahead_behind(commit1, commit2, ahead, behind) < 0)
-		goto on_error;
-
-	if (!result) {
-		git_revwalk_free(walk);
-		return GIT_ENOTFOUND;
-	}
-
-	git_commit_list_free(&result);
-	git_revwalk_free(walk);
-
-	return 0;
-
-on_error:
-	git_revwalk_free(walk);
-	return -1;
-}
diff --git a/tests-clar/revwalk/mergebase.c b/tests-clar/revwalk/mergebase.c
index a44e35b..2cd1860 100644
--- a/tests-clar/revwalk/mergebase.c
+++ b/tests-clar/revwalk/mergebase.c
@@ -20,7 +20,7 @@ void test_revwalk_mergebase__cleanup(void)
 void test_revwalk_mergebase__single1(void)
 {
 	git_oid result, one, two, expected;
-	int ahead, behind;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "c47800c7266a2be04c571c04d5a6614691ea99bd "));
 	cl_git_pass(git_oid_fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
@@ -29,11 +29,11 @@ void test_revwalk_mergebase__single1(void)
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert(git_oid_cmp(&result, &expected) == 0);
 
-	cl_git_pass(git_count_ahead_behind(&ahead, &behind, _repo, &one, &two));
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &one, &two));
 	cl_assert(ahead == 2);
 	cl_assert(behind == 1);
 
-	cl_git_pass(git_count_ahead_behind(&ahead, &behind, _repo, &two, &one));
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &two, &one));
 	cl_assert(ahead == 1);
 	cl_assert(behind == 2);
 }
@@ -41,7 +41,7 @@ void test_revwalk_mergebase__single1(void)
 void test_revwalk_mergebase__single2(void)
 {
 	git_oid result, one, two, expected;
-	int ahead, behind;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af"));
 	cl_git_pass(git_oid_fromstr(&two, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
@@ -50,11 +50,11 @@ void test_revwalk_mergebase__single2(void)
 	cl_git_pass(git_merge_base(&result, _repo, &one, &two));
 	cl_assert(git_oid_cmp(&result, &expected) == 0);
 
-	cl_git_pass(git_count_ahead_behind( &ahead, &behind, _repo, &one, &two));
+	cl_git_pass(git_graph_ahead_behind( &ahead, &behind, _repo, &one, &two));
 	cl_assert(ahead == 4);
 	cl_assert(behind == 1);
 
-	cl_git_pass(git_count_ahead_behind( &ahead, &behind, _repo, &two, &one));
+	cl_git_pass(git_graph_ahead_behind( &ahead, &behind, _repo, &two, &one));
 	cl_assert(ahead == 1);
 	cl_assert(behind == 4);
 }
@@ -62,7 +62,7 @@ void test_revwalk_mergebase__single2(void)
 void test_revwalk_mergebase__merged_branch(void)
 {
 	git_oid result, one, two, expected;
-	int ahead, behind;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "a65fedf39aefe402d3bb6e24df4d4f5fe4547750"));
 	cl_git_pass(git_oid_fromstr(&two, "9fd738e8f7967c078dceed8190330fc8648ee56a"));
@@ -74,11 +74,11 @@ void test_revwalk_mergebase__merged_branch(void)
 	cl_git_pass(git_merge_base(&result, _repo, &two, &one));
 	cl_assert(git_oid_cmp(&result, &expected) == 0);
 
-	cl_git_pass(git_count_ahead_behind(&ahead, &behind, _repo, &one, &two));
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &one, &two));
 	cl_assert(ahead == 0);
 	cl_assert(behind == 3);
 
-	cl_git_pass(git_count_ahead_behind(&ahead, &behind, _repo, &two, &one));
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo, &two, &one));
 	cl_assert(ahead == 3);
 	cl_assert(behind == 0);
 }
@@ -86,11 +86,11 @@ void test_revwalk_mergebase__merged_branch(void)
 void test_revwalk_meregebase__two_way_merge(void)
 {
 	git_oid one, two;
-	int ahead, behind;
+	size_t ahead, behind;
 
 	cl_git_pass(git_oid_fromstr(&one, "9b219343610c88a1187c996d0dc58330b55cee28"));
 	cl_git_pass(git_oid_fromstr(&two, "a953a018c5b10b20c86e69fef55ebc8ad4c5a417"));
-	cl_git_pass(git_count_ahead_behind(&ahead, &behind, _repo2, &one, &two));
+	cl_git_pass(git_graph_ahead_behind(&ahead, &behind, _repo2, &one, &two));
 
 	cl_assert(ahead == 8);
 	cl_assert(behind == 2);
@@ -99,7 +99,7 @@ void test_revwalk_meregebase__two_way_merge(void)
 void test_revwalk_mergebase__no_common_ancestor_returns_ENOTFOUND(void)
 {
 	git_oid result, one, two;
-	int ahead, behind;
+	size_t ahead, behind;
 	int error;
 
 	cl_git_pass(git_oid_fromstr(&one, "763d71aadf09a7951596c9746c024e7eece7c7af"));
@@ -110,7 +110,7 @@ void test_revwalk_mergebase__no_common_ancestor_returns_ENOTFOUND(void)
 
 	cl_assert_equal_i(GIT_ENOTFOUND, error);
 
-	cl_git_fail(git_count_ahead_behind(&ahead, &behind, _repo, &one, &two));
+	cl_git_fail(git_graph_ahead_behind(&ahead, &behind, _repo, &one, &two));
 	cl_git_fail(error);
 
 	cl_assert_equal_i(GIT_ENOTFOUND, error);