sparse-checkout: split out code for tweaking settings config

`init` has some code for handling updates to either cone mode or
the sparse-index setting.  We would like to be able to reuse this
elsewhere, namely in `set` and `reapply`.  Split this function out,
and make it slightly more general so it can handle being called from
the new callers.

Reviewed-by: Derrick Stolee <[email protected]>
Reviewed-by: Victoria Dye <[email protected]>
Signed-off-by: Elijah Newren <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: newren

builtin/sparse-checkout.c

@@ -383,6 +383,41 @@ static int set_config(enum sparse_checkout_mode mode)
 	return 0;
 }
 
+static int update_modes(int *cone_mode, int *sparse_index)
+{
+	int mode, record_mode;
+
+	/* Determine if we need to record the mode; ensure sparse checkout on */
+	record_mode = (*cone_mode != -1) || !core_apply_sparse_checkout;
+
+	/* If not specified, use previous definition of cone mode */
+	if (*cone_mode == -1 && core_apply_sparse_checkout)
+		*cone_mode = core_sparse_checkout_cone;
+
+	/* Set cone/non-cone mode appropriately */
+	core_apply_sparse_checkout = 1;
+	if (*cone_mode == 1) {
+		mode = MODE_CONE_PATTERNS;
+		core_sparse_checkout_cone = 1;
+	} else {
+		mode = MODE_ALL_PATTERNS;
+	}
+	if (record_mode && set_config(mode))
+		return 1;
+
+	/* Set sparse-index/non-sparse-index mode if specified */
+	if (*sparse_index >= 0) {
+		if (set_sparse_index_config(the_repository, *sparse_index) < 0)
+			die(_("failed to modify sparse-index config"));
+
+		/* force an index rewrite */
+		repo_read_index(the_repository);
+		the_repository->index->updated_workdir = 1;
+	}
+
+	return 0;
+}
+
 static char const * const builtin_sparse_checkout_init_usage[] = {
 	N_("git sparse-checkout init [--cone] [--[no-]sparse-index]"),
 	NULL
@@ -399,7 +434,6 @@ static int sparse_checkout_init(int argc, const char **argv)
 	char *sparse_filename;
 	int res;
 	struct object_id oid;
-	int mode;
 	struct strbuf pattern = STRBUF_INIT;
 
 	static struct option builtin_sparse_checkout_init_options[] = {
@@ -412,37 +446,21 @@ static int sparse_checkout_init(int argc, const char **argv)
 
 	repo_read_index(the_repository);
 
+	init_opts.cone_mode = -1;
 	init_opts.sparse_index = -1;
 
 	argc = parse_options(argc, argv, NULL,
 			     builtin_sparse_checkout_init_options,
 			     builtin_sparse_checkout_init_usage, 0);
 
-	if (init_opts.cone_mode) {
-		mode = MODE_CONE_PATTERNS;
-		core_sparse_checkout_cone = 1;
-	} else
-		mode = MODE_ALL_PATTERNS;
-
-	if (set_config(mode))
+	if (update_modes(&init_opts.cone_mode, &init_opts.sparse_index))
 		return 1;
 
 	memset(&pl, 0, sizeof(pl));
 
 	sparse_filename = get_sparse_checkout_filename();
 	res = add_patterns_from_file_to_list(sparse_filename, "", 0, &pl, NULL, 0);
 
-	if (init_opts.sparse_index >= 0) {
-		if (set_sparse_index_config(the_repository, init_opts.sparse_index) < 0)
-			die(_("failed to modify sparse-index config"));
-
-		/* force an index rewrite */
-		repo_read_index(the_repository);
-		the_repository->index->updated_workdir = 1;
-	}
-
-	core_apply_sparse_checkout = 1;
-
 	/* If we already have a sparse-checkout file, use it. */
 	if (res >= 0) {
 		free(sparse_filename);