Add index updating to checkout

Make checkout update entries in the index for all files that are
updated and/or removed, unless flag GIT_CHECKOUT_DONT_UPDATE_INDEX
is given.  To do this, iterators were extended to allow a little
more introspection into the index being iterated over, etc.

include/git2/checkout.h

@@ -140,8 +140,11 @@ typedef enum {
 	/** Only update existing files, don't create new ones */
 	GIT_CHECKOUT_UPDATE_ONLY = (1u << 7),
 
+	/** Normally checkout updates index entries as it goes; this stops that */
+	GIT_CHECKOUT_DONT_UPDATE_INDEX = (1u << 8),
+
 	/** Don't refresh index/config/etc before doing checkout */
-	GIT_CHECKOUT_NO_REFRESH = (1u << 8),
+	GIT_CHECKOUT_NO_REFRESH = (1u << 9),
 
 	/**
 	 * THE FOLLOWING OPTIONS ARE NOT YET IMPLEMENTED

src/iterator.c

@@ -988,6 +988,33 @@ fail:
 	return -1;
 }
 
+git_index *git_iterator_index_get_index(git_iterator *iter)
+{
+	if (iter->type == GIT_ITERATOR_SPOOLANDSORT)
+		iter = ((spoolandsort_iterator *)iter)->wrapped;
+
+	if (iter->type == GIT_ITERATOR_INDEX)
+		return ((index_iterator *)iter)->index;
+
+	return NULL;
+}
+
+git_iterator_type_t git_iterator_inner_type(git_iterator *iter)
+{
+	if (iter->type == GIT_ITERATOR_SPOOLANDSORT)
+		iter = ((spoolandsort_iterator *)iter)->wrapped;
+
+	return iter->type;
+}
+
+git_iterator *git_iterator_spoolandsort_inner_iterator(git_iterator *iter)
+{
+	if (iter->type == GIT_ITERATOR_SPOOLANDSORT)
+		return ((spoolandsort_iterator *)iter)->wrapped;
+
+	return NULL;
+}
+
 int git_iterator_current_tree_entry(
 	git_iterator *iter, const git_tree_entry **tree_entry)
 {

src/iterator.h

@@ -193,4 +193,12 @@ extern int git_iterator_cmp(
 extern int git_iterator_current_workdir_path(
 	git_iterator *iter, git_buf **path);
 
+
+extern git_index *git_iterator_index_get_index(git_iterator *iter);
+
+extern git_iterator_type_t git_iterator_inner_type(git_iterator *iter);
+
+extern git_iterator *git_iterator_spoolandsort_inner_iterator(
+	git_iterator *iter);
+
 #endif

tests-clar/checkout/tree.c

@@ -50,28 +50,29 @@ void test_checkout_tree__can_checkout_a_subdirectory_from_a_commit(void)
 
 void test_checkout_tree__can_checkout_and_remove_directory(void)
 {
-	git_reference *head;
 	cl_assert_equal_i(false, git_path_isdir("./testrepo/ab/"));
 
-	// Checkout brach "subtrees" and update HEAD, so that HEAD matches the current working tree
+	/* Checkout brach "subtrees" and update HEAD, so that HEAD matches the
+	 * current working tree
+	 */
 	cl_git_pass(git_revparse_single(&g_object, g_repo, "subtrees"));
 	cl_git_pass(git_checkout_tree(g_repo, g_object, &g_opts));
-	cl_git_pass(git_reference_lookup(&head, g_repo, "HEAD"));
-	cl_git_pass(git_reference_symbolic_set_target(head, "refs/heads/subtrees"));
-	git_reference_free(head);
-	
+
+	cl_git_pass(git_repository_set_head(g_repo, "refs/heads/subtrees"));
+
 	cl_assert_equal_i(true, git_path_isdir("./testrepo/ab/"));
 	cl_assert_equal_i(true, git_path_isfile("./testrepo/ab/de/2.txt"));
 	cl_assert_equal_i(true, git_path_isfile("./testrepo/ab/de/fgh/1.txt"));
 
-	// Checkout brach "master" and update HEAD, so that HEAD matches the current working tree
+	/* Checkout brach "master" and update HEAD, so that HEAD matches the
+	 * current working tree
+	 */
 	cl_git_pass(git_revparse_single(&g_object, g_repo, "master"));
 	cl_git_pass(git_checkout_tree(g_repo, g_object, &g_opts));
-	cl_git_pass(git_reference_lookup(&head, g_repo, "HEAD"));
-	cl_git_pass(git_reference_symbolic_set_target(head, "refs/heads/master"));
-	git_reference_free(head);
 
-	// This directory should no longer exist
+	cl_git_pass(git_repository_set_head(g_repo, "refs/heads/master"));
+
+	/* This directory should no longer exist */
 	cl_assert_equal_i(false, git_path_isdir("./testrepo/ab/"));
 }