From 97101f1f82ba55015484c124d2f2990c0773b75c Mon Sep 17 00:00:00 2001
From: Jakub Sitnicki <jsitnicki@gmail.com>
Date: Mon, 7 Jul 2014 06:23:22 +0200
Subject: [PATCH] mu: Prune empty container when an only child gets promoted to
 the root set

---
 lib/mu-container.c | 17 ++++++++++++++++-
 lib/mu-container.h | 17 +++++++++++++++--
 lib/mu-threader.c  | 13 +++----------
 3 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/lib/mu-container.c b/lib/mu-container.c
index 7011fec5..a201c30c 100644
--- a/lib/mu-container.c
+++ b/lib/mu-container.c
@@ -263,9 +263,24 @@ mu_container_foreach (MuContainer *c, MuContainerForeachFunc func,
 	return func (c, user_data);
 }
 
+MuContainer*
+mu_container_splice_children (MuContainer *c, MuContainer *sibling)
+{
+	MuContainer *children;
+
+	g_return_val_if_fail (c, NULL);
+	g_return_val_if_fail (sibling, NULL);
+
+	children = sibling->child;
+	sibling->child = NULL;
+
+	c = mu_container_remove_sibling (c, sibling);
+
+	return mu_container_append_siblings (c, children);
+}
 
 MuContainer*
-mu_container_splice_children (MuContainer *parent, MuContainer *child)
+mu_container_splice_grandchildren (MuContainer *parent, MuContainer *child)
 {
 	MuContainer *newchild;
 
diff --git a/lib/mu-container.h b/lib/mu-container.h
index ec9d7f72..c80f0273 100644
--- a/lib/mu-container.h
+++ b/lib/mu-container.h
@@ -122,6 +122,19 @@ MuContainer* mu_container_remove_child (MuContainer *c, MuContainer *child);
  */
 MuContainer* mu_container_remove_sibling (MuContainer *c, MuContainer *sibling);
 
+/**
+ * promote sibling's children to be this container's siblings and
+ * remove the sibling
+ *
+ * @param c a container instance
+ * @param sibling a sibling of this container
+ *
+ * @return the container with the sibling's children promoted and the
+ * sibling itself removed
+ */
+
+MuContainer* mu_container_splice_children (MuContainer *c,
+                                           MuContainer *sibling);
 
 /**
  * promote child's children to be parent's children and remove child
@@ -131,8 +144,8 @@ MuContainer* mu_container_remove_sibling (MuContainer *c, MuContainer *sibling);
  *
  * @return the new container with it's children's children promoted
  */
-MuContainer* mu_container_splice_children (MuContainer *parent,
-					   MuContainer *child);
+MuContainer* mu_container_splice_grandchildren (MuContainer *parent,
+                                                MuContainer *child);
 
 typedef gboolean (*MuContainerForeachFunc) (MuContainer*, gpointer);
 
diff --git a/lib/mu-threader.c b/lib/mu-threader.c
index 719508d2..c42e166c 100644
--- a/lib/mu-threader.c
+++ b/lib/mu-threader.c
@@ -388,7 +388,7 @@ prune_maybe (MuContainer *c)
 		if (cur->flags & MU_CONTAINER_FLAG_DELETE)
 			c = mu_container_remove_child (c, cur);
 		else if (cur->flags & MU_CONTAINER_FLAG_SPLICE)
-			c = mu_container_splice_children (c, cur);
+			c = mu_container_splice_grandchildren (c, cur);
 	}
 
 	g_return_val_if_fail (c, FALSE);
@@ -433,17 +433,10 @@ prune_empty_containers (MuContainer *root_set)
 
 	/* and prune the root_set itself... */
 	for (cur = root_set; cur; cur = cur->next) {
-
 		if (cur->flags & MU_CONTAINER_FLAG_DELETE)
 			root_set = mu_container_remove_sibling (root_set, cur);
-
-		else if (cur->flags & MU_CONTAINER_FLAG_SPLICE) {
-			MuContainer *newchild;
-			newchild = cur->child;
-			cur->child = NULL;
-			root_set = mu_container_append_siblings (root_set,
-								 newchild);
-		}
+		else if (cur->flags & MU_CONTAINER_FLAG_SPLICE)
+			root_set = mu_container_splice_children (root_set, cur);
 	}
 
 	return root_set;