[Qemu-devel] [PATCH 1/2] qom: add a generic mechanism to resolve paths

2014-06-05 Thread Paolo Bonzini 
It may be desirable to have custom link properties that do more
than just store an object.  Even the addition of a check
function is not enough if setting the link has side effects
or if a non-standard reference counting is preferrable.

Avoid the assumption that the opaque field of a link is a
LinkProperty struct, by adding a generic resolve callback
to ObjectProperty.

Signed-off-by: Paolo Bonzini pbonz...@redhat.com
---
 include/qom/object.h | 49 ++
 qom/object.c | 55 ++--
 2 files changed, 85 insertions(+), 19 deletions(-)

diff --git a/include/qom/object.h b/include/qom/object.h
index a641dcd..f8ab845 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -304,6 +304,23 @@ typedef void (ObjectPropertyAccessor)(Object *obj,
   Error **errp);
 
 /**
+ * ObjectPropertyResolve:
+ * @obj: the object that owns the property
+ * @opaque: the opaque registered with the property
+ * @part: the name of the property
+ *
+ * If @path is the path that led to @obj, the function should
+ * return the Object corresponding to @path/@part.  If #NULL
+ * is returned, @path/@part is not a valid object path.
+ *
+ * The returned object can also be used as a starting point
+ * to resolve a relative path starting with @part.
+ */
+typedef Object *(ObjectPropertyResolve)(Object *obj,
+void *opaque,
+const char *part);
+
+/**
  * ObjectPropertyRelease:
  * @obj: the object that owns the property
  * @name: the name of the property
@@ -321,6 +338,7 @@ typedef struct ObjectProperty
 gchar *type;
 ObjectPropertyAccessor *get;
 ObjectPropertyAccessor *set;
+ObjectPropertyResolve *resolve;
 ObjectPropertyRelease *release;
 void *opaque;
 
@@ -769,6 +787,37 @@ void object_ref(Object *obj);
 void object_unref(Object *obj);
 
 /**
+ * object_property_add_full:
+ * @obj: the object to add a property to
+ * @name: the name of the property.  This can contain any character except for
+ *  a forward slash.  In general, you should use hyphens '-' instead of
+ *  underscores '_' when naming properties.
+ * @type: the type name of the property.  This namespace is pretty loosely
+ *   defined.  Sub namespaces are constructed by using a prefix and then
+ *   to angle brackets.  For instance, the type 'virtio-net-pci' in the
+ *   'link' namespace would be 'linkvirtio-net-pci'.
+ * @get: The getter to be called to read a property.  If this is NULL, then
+ *   the property cannot be read.
+ * @set: the setter to be called to write a property.  If this is NULL,
+ *   then the property cannot be written.
+ * @resolve: called when the property name is used as part of an object
+ *   path.  This is meant for cases when you want to have custom link
+ *   properties.  If it is NULL, the property name cannot be used as part
+ *   of a valid object path.
+ * @release: called when the property is removed from the object.  This is
+ *   meant to allow a property to free its opaque upon object
+ *   destruction.  This may be NULL.
+ * @opaque: an opaque pointer to pass to the callbacks for the property
+ * @errp: returns an error if this function fails
+ */
+void object_property_add_full(Object *obj, const char *name, const char *type,
+ ObjectPropertyAccessor *get,
+ ObjectPropertyAccessor *set,
+ ObjectPropertyResolve *resolve,
+ ObjectPropertyRelease *release,
+ void *opaque, Error **errp);
+
+/**
  * object_property_add:
  * @obj: the object to add a property to
  * @name: the name of the property.  This can contain any character except for
diff --git a/qom/object.c b/qom/object.c
index e42b254..fcdd0da 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -355,11 +355,6 @@ static inline bool object_property_is_child(ObjectProperty 
*prop)
 return strstart(prop-type, child, NULL);
 }
 
-static inline bool object_property_is_link(ObjectProperty *prop)
-{
-return strstart(prop-type, link, NULL);
-}
-
 static void object_property_del_all(Object *obj)
 {
 while (!QTAILQ_EMPTY(obj-properties)) {
@@ -727,9 +722,10 @@ void object_unref(Object *obj)
 }
 }
 
-void object_property_add(Object *obj, const char *name, const char *type,
+void object_property_add_full(Object *obj, const char *name, const char *type,
  ObjectPropertyAccessor *get,
  ObjectPropertyAccessor *set,
+ ObjectPropertyResolve *resolve,
  ObjectPropertyRelease *release,
  void *opaque, Error **errp)
 {
@@ -751,12 +747,23 @@ void object_property_add(Object *obj, const char *name, 
const char *type,
 
 prop-get = get;
 prop-set = set;
+prop-resolve = resolve;
 prop-release = release;

Re: [Qemu-devel] [PATCH 1/2] qom: add a generic mechanism to resolve paths

2014-06-05 Thread Peter Crosthwaite 
On Thu, Jun 5, 2014 at 9:23 PM, Paolo Bonzini pbonz...@redhat.com wrote:
 It may be desirable to have custom link properties that do more
 than just store an object.  Even the addition of a check
 function is not enough if setting the link has side effects
 or if a non-standard reference counting is preferrable.

 Avoid the assumption that the opaque field of a link is a
 LinkProperty struct, by adding a generic resolve callback
 to ObjectProperty.

 Signed-off-by: Paolo Bonzini pbonz...@redhat.com
 ---
  include/qom/object.h | 49 ++
  qom/object.c | 55 
 ++--
  2 files changed, 85 insertions(+), 19 deletions(-)

 diff --git a/include/qom/object.h b/include/qom/object.h
 index a641dcd..f8ab845 100644
 --- a/include/qom/object.h
 +++ b/include/qom/object.h
 @@ -304,6 +304,23 @@ typedef void (ObjectPropertyAccessor)(Object *obj,
Error **errp);

  /**
 + * ObjectPropertyResolve:
 + * @obj: the object that owns the property
 + * @opaque: the opaque registered with the property
 + * @part: the name of the property
 + *
 + * If @path is the path that led to @obj, the function should
 + * return the Object corresponding to @path/@part.  If #NULL
 + * is returned, @path/@part is not a valid object path.
 + *
 + * The returned object can also be used as a starting point
 + * to resolve a relative path starting with @part.
 + */
 +typedef Object *(ObjectPropertyResolve)(Object *obj,
 +void *opaque,
 +const char *part);
 +
 +/**
   * ObjectPropertyRelease:
   * @obj: the object that owns the property
   * @name: the name of the property
 @@ -321,6 +338,7 @@ typedef struct ObjectProperty
  gchar *type;
  ObjectPropertyAccessor *get;
  ObjectPropertyAccessor *set;
 +ObjectPropertyResolve *resolve;
  ObjectPropertyRelease *release;
  void *opaque;

 @@ -769,6 +787,37 @@ void object_ref(Object *obj);
  void object_unref(Object *obj);

  /**
 + * object_property_add_full:
 + * @obj: the object to add a property to
 + * @name: the name of the property.  This can contain any character except 
 for
 + *  a forward slash.  In general, you should use hyphens '-' instead of
 + *  underscores '_' when naming properties.
 + * @type: the type name of the property.  This namespace is pretty loosely
 + *   defined.  Sub namespaces are constructed by using a prefix and then
 + *   to angle brackets.  For instance, the type 'virtio-net-pci' in the
 + *   'link' namespace would be 'linkvirtio-net-pci'.
 + * @get: The getter to be called to read a property.  If this is NULL, then
 + *   the property cannot be read.
 + * @set: the setter to be called to write a property.  If this is NULL,
 + *   then the property cannot be written.
 + * @resolve: called when the property name is used as part of an object
 + *   path.  This is meant for cases when you want to have custom link
 + *   properties.  If it is NULL, the property name cannot be used as part
 + *   of a valid object path.
 + * @release: called when the property is removed from the object.  This is
 + *   meant to allow a property to free its opaque upon object
 + *   destruction.  This may be NULL.
 + * @opaque: an opaque pointer to pass to the callbacks for the property
 + * @errp: returns an error if this function fails
 + */
 +void object_property_add_full(Object *obj, const char *name, const char 
 *type,
 + ObjectPropertyAccessor *get,
 + ObjectPropertyAccessor *set,
 + ObjectPropertyResolve *resolve,
 + ObjectPropertyRelease *release,
 + void *opaque, Error **errp);
 +
 +/**
   * object_property_add:
   * @obj: the object to add a property to
   * @name: the name of the property.  This can contain any character except 
 for
 diff --git a/qom/object.c b/qom/object.c
 index e42b254..fcdd0da 100644
 --- a/qom/object.c
 +++ b/qom/object.c
 @@ -355,11 +355,6 @@ static inline bool 
 object_property_is_child(ObjectProperty *prop)
  return strstart(prop-type, child, NULL);
  }

 -static inline bool object_property_is_link(ObjectProperty *prop)
 -{
 -return strstart(prop-type, link, NULL);
 -}
 -
  static void object_property_del_all(Object *obj)
  {
  while (!QTAILQ_EMPTY(obj-properties)) {
 @@ -727,9 +722,10 @@ void object_unref(Object *obj)
  }
  }

 -void object_property_add(Object *obj, const char *name, const char *type,
 +void object_property_add_full(Object *obj, const char *name, const char 
 *type,
   ObjectPropertyAccessor *get,
   ObjectPropertyAccessor *set,
 + ObjectPropertyResolve *resolve,
   ObjectPropertyRelease *release,
   void *opaque, Error **errp)
  {
 @@ -751,12