libstage: add stage, rename adopt->replace in stage_conf_t

In preparation for supporting caller-supplied stage memory, add another
stage_t pointer to the conf called .stage.

The naming of .adopt was always awkward and resulted from the reuse of
the .parent pointer to indicate the stage to replace.  Now that there's
a .stage member, just rename .adopt to .replace, with the same semantics.

At some point I need to firm up what .replace does with the other conf
data.  Currently, only the name, ops, and object, are updated.  The
existing active/locked/alpha etc are retained unchanged, ignored from
the conf.  This can be surprising/unexpected to someone performing a
replace through the .conf, and it would probably be convenient to be
able to set everything during a replace.  So there should probably be
a convenience helper for constructing a conf from an existing stage,
which can then be overridden selectively while passing to a new().

2 files changed, 6 insertions, 6 deletions

diff --git a/src/stage.c b/src/stage.c
index 8a540a8..b072050 100644
--- a/src/stage.c
+++ b/src/stage.c
@@ -88,18 +88,18 @@ static void _stage_free(stage_t *stage)
 
 /* returns a new stage, attached at the specified layer under parent if supplied */
 /* layer has no effect when parent == NULL */
-/* if adopt is set, parent must be set and is instead replaced internally and returned */
+/* if replace is set, conf.stage must be set, its internals are replaced and it's returned as new */
 stage_t * stage_new(const stage_conf_t *conf, const stage_ops_t *ops, void *object)
 {
 	stage_t	*stage;
 
 	assert(conf);
 	assert(conf->parent || !conf->layer);
-	assert(conf->parent || !conf->adopt);
+	assert(conf->stage || !conf->replace);
 	assert(conf->layer < STAGE_LAYERS_MAX);
 
-	if (conf->adopt)
-		return stage_replace(conf->parent, conf->name, ops, object);
+	if (conf->replace)
+		return stage_replace(conf->stage, conf->name, ops, object);
 
 	stage = _stage_new(conf->name, ops, object);
 	if (!stage)
diff --git a/src/stage.h b/src/stage.h
index 785ddf5..40f2057 100644
--- a/src/stage.h
+++ b/src/stage.h
@@ -33,14 +33,14 @@ typedef struct stage_ops_t {
 } stage_ops_t;
 
 typedef struct stage_conf_t {
-	stage_t			*parent;
+	stage_t			*parent, *stage;
 	int			layer;
 	const char		*name;
 	float			alpha;
 	unsigned		active:1;
 	unsigned		locked:1;
 	unsigned		dirty:1;
-	unsigned		adopt:1;
+	unsigned		replace:1;
 } stage_conf_t;
 
 stage_t * stage_new(const stage_conf_t *conf, const stage_ops_t *ops, void *object);