[Qemu-devel] [RFC 5/7] qdev: add get_pointer_and_free() for temporary strings

[Stefan Hajnoczi <stefanha@redhat.com>]

get_pointer() assumes the string has unspecified lifetime (at least as
long as the object is alive).  In some cases we can only produce a
temporary string that should be freed when get_pointer() is done.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/core/qdev-properties-system.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/hw/core/qdev-properties-system.c b/hw/core/qdev-properties-system.c
index 729efa8..200f853 100644
--- a/hw/core/qdev-properties-system.c
+++ b/hw/core/qdev-properties-system.c
@@ -31,6 +31,20 @@ static void get_pointer(Object *obj, Visitor *v, Property *prop,
     visit_type_str(v, &p, name, errp);
 }
 
+/* Same as get_pointer() but frees heap-allocated print() return value */
+static void get_pointer_and_free(Object *obj, Visitor *v, Property *prop,
+                                 char *(*print)(void *ptr),
+                                 const char *name, Error **errp)
+{
+    DeviceState *dev = DEVICE(obj);
+    void **ptr = qdev_get_prop_ptr(dev, prop);
+    char *p;
+
+    p = *ptr ? print(*ptr) : g_strdup("");
+    visit_type_str(v, &p, name, errp);
+    g_free(p);
+}
+
 static void set_pointer(Object *obj, Visitor *v, Property *prop,
                         int (*parse)(DeviceState *dev, const char *str,
                                      void **ptr),
-- 
1.8.4.2