reftable/stack: expose option to disable auto-compaction

The reftable stack already has a variable to configure whether or not to
run auto-compaction, but it is inaccessible to users of the library.
There exist use cases where a caller may want to have more control over
auto-compaction.

Move the `disable_auto_compact` option into `reftable_write_options` to
allow external callers to disable auto-compaction. This will be used in
a subsequent commit.

Signed-off-by: Justin Tobler <jltobler@gmail.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/reftable/reftable-writer.h b/reftable/reftable-writer.h
index 7c7cae5..155bf0b 100644
--- a/reftable/reftable-writer.h
+++ b/reftable/reftable-writer.h
@@ -46,6 +46,9 @@
 	 *   is a single line, and add '\n' if missing.
 	 */
 	unsigned exact_log_message : 1;
+
+	/* boolean: Prevent auto-compaction of tables. */
+	unsigned disable_auto_compact : 1;
 };
 
 /* reftable_block_stats holds statistics for a single block type */
diff --git a/reftable/stack.c b/reftable/stack.c
index dde50b6..1a7cdad 100644
--- a/reftable/stack.c
+++ b/reftable/stack.c
@@ -680,7 +680,7 @@
 	if (err)
 		goto done;
 
-	if (!add->stack->disable_auto_compact) {
+	if (!add->stack->config.disable_auto_compact) {
 		/*
 		 * Auto-compact the stack to keep the number of tables in
 		 * control. It is possible that a concurrent writer is already
diff --git a/reftable/stack.h b/reftable/stack.h
index d919455..c862053 100644
--- a/reftable/stack.h
+++ b/reftable/stack.h
@@ -19,7 +19,6 @@
 	int list_fd;
 
 	char *reftable_dir;
-	int disable_auto_compact;
 
 	struct reftable_write_options config;
 
diff --git a/reftable/stack_test.c b/reftable/stack_test.c
index 7b2a8b1..fc14b1d 100644
--- a/reftable/stack_test.c
+++ b/reftable/stack_test.c
@@ -315,7 +315,7 @@
 		 * we can ensure that we indeed honor this setting and have
 		 * better control over when exactly auto compaction runs.
 		 */
-		st->disable_auto_compact = i != n;
+		st->config.disable_auto_compact = i != n;
 
 		err = reftable_stack_new_addition(&add, st);
 		EXPECT_ERR(err);
@@ -487,6 +487,7 @@
 	struct reftable_write_options cfg = {
 		.exact_log_message = 1,
 		.default_permissions = 0660,
+		.disable_auto_compact = 1,
 	};
 	struct reftable_stack *st = NULL;
 	char *dir = get_tmp_dir(__LINE__);
@@ -498,7 +499,6 @@
 
 	err = reftable_new_stack(&st, dir, cfg);
 	EXPECT_ERR(err);
-	st->disable_auto_compact = 1;
 
 	for (i = 0; i < N; i++) {
 		char buf[256];
@@ -925,7 +925,9 @@
 
 static void test_reftable_stack_auto_compaction(void)
 {
-	struct reftable_write_options cfg = { 0 };
+	struct reftable_write_options cfg = {
+		.disable_auto_compact = 1,
+	};
 	struct reftable_stack *st = NULL;
 	char *dir = get_tmp_dir(__LINE__);
 
@@ -935,7 +937,6 @@
 	err = reftable_new_stack(&st, dir, cfg);
 	EXPECT_ERR(err);
 
-	st->disable_auto_compact = 1; /* call manually below for coverage. */
 	for (i = 0; i < N; i++) {
 		char name[100];
 		struct reftable_ref_record ref = {
@@ -984,7 +985,7 @@
 		 * we can ensure that we indeed honor this setting and have
 		 * better control over when exactly auto compaction runs.
 		 */
-		st->disable_auto_compact = i != n;
+		st->config.disable_auto_compact = i != n;
 
 		strbuf_reset(&refname);
 		strbuf_addf(&refname, "branch-%04d", i);