Add operations to qlist to allow it to be used as a stack

This makes lists no longer invariant. It's a very useful bit of functionality
though.

To deal with the fact that lists are no longer invariant, introduce a deep
copy mechanism for lists.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 56 insertions, 0 deletions

diff --git a/qlist.c b/qlist.c
index ba2c66c01c..5fccb7d095 100644
--- a/qlist.c
+++ b/qlist.c
@@ -37,6 +37,23 @@ QList *qlist_new(void)
     return qlist;
 }
 
+static void qlist_copy_elem(QObject *obj, void *opaque)
+{
+    QList *dst = opaque;
+
+    qobject_incref(obj);
+    qlist_append_obj(dst, obj);
+}
+
+QList *qlist_copy(QList *src)
+{
+    QList *dst = qlist_new();
+
+    qlist_iter(src, qlist_copy_elem, dst);
+
+    return dst;
+}
+
 /**
  * qlist_append_obj(): Append an QObject into QList
  *
@@ -67,6 +84,45 @@ void qlist_iter(const QList *qlist,
         iter(entry->value, opaque);
 }
 
+QObject *qlist_pop(QList *qlist)
+{
+    QListEntry *entry;
+    QObject *ret;
+
+    if (qlist == NULL || QTAILQ_EMPTY(&qlist->head)) {
+        return NULL;
+    }
+
+    entry = QTAILQ_FIRST(&qlist->head);
+    QTAILQ_REMOVE(&qlist->head, entry, next);
+
+    ret = entry->value;
+    qemu_free(entry);
+
+    return ret;
+}
+
+QObject *qlist_peek(QList *qlist)
+{
+    QListEntry *entry;
+    QObject *ret;
+
+    if (qlist == NULL || QTAILQ_EMPTY(&qlist->head)) {
+        return NULL;
+    }
+
+    entry = QTAILQ_FIRST(&qlist->head);
+
+    ret = entry->value;
+
+    return ret;
+}
+
+int qlist_empty(const QList *qlist)
+{
+    return QTAILQ_EMPTY(&qlist->head);
+}
+
 /**
  * qobject_to_qlist(): Convert a QObject into a QList
  */