Calling a function for children of a certain type is a recurring pattern
in the QEMU code base. In order to avoid the need to setup the same boiler
plate again and again, introduce a variant of object_child_foreach() that
only considers children of the given type.

Signed-off-by: Greg Kurz <groug@kaod.org>
---
 include/qom/object.h |   35 +++++++++++++++++++++++++++++++++++
 qom/object.c         |   30 +++++++++++++++++++++++-------
 2 files changed, 58 insertions(+), 7 deletions(-)

diff --git a/include/qom/object.h b/include/qom/object.h
index 128d00c77fd6..e9e3c2eae8ed 100644
--- a/include/qom/object.h
+++ b/include/qom/object.h
@@ -1728,6 +1728,41 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
 int object_child_foreach_recursive(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque);
+
+/**
+ * object_child_foreach_type:
+ * @obj: the object whose children will be navigated
+ * @typename: the type of child objects to consider
+ * @fn: the iterator function to be called
+ * @opaque: an opaque value that will be passed to the iterator
+ *
+ * This is similar to object_child_foreach, but it only calls @fn for
+ * child objects of the give @typename.
+ *
+ * Returns: The last value returned by @fn, or 0 if there is no child of
+ * the given @typename.
+ */
+int object_child_foreach_type(Object *obj, const char *typename,
+                              int (*fn)(Object *child, void *opaque),
+                              void *opaque);
+
+/**
+ * object_child_foreach_recursive_type:
+ * @obj: the object whose children will be navigated
+ * @typename: the type of child objects to consider
+ * @fn: the iterator function to be called
+ * @opaque: an opaque value that will be passed to the iterator
+ *
+ * This is similar to object_child_foreach_recursive, but it only calls
+ * @fn for child objects of the give @typename.
+ *
+ * Returns: The last value returned by @fn, or 0 if there is no child of
+ * the given @typename.
+ */
+int object_child_foreach_recursive_type(Object *obj, const char *typename,
+                                        int (*fn)(Object *child, void *opaque),
+                                        void *opaque);
+
 /**
  * container_get:
  * @root: root of the #path, e.g., object_get_root()
diff --git a/qom/object.c b/qom/object.c
index 6fa9c619fac4..a2dec1261ff7 100644
--- a/qom/object.c
+++ b/qom/object.c
@@ -986,7 +986,7 @@ void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
     enumerating_types = false;
 }
 
-static int do_object_child_foreach(Object *obj,
+static int do_object_child_foreach(Object *obj, const char *typename,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque, bool recurse)
 {
@@ -999,12 +999,14 @@ static int do_object_child_foreach(Object *obj,
         if (object_property_is_child(prop)) {
             Object *child = prop->opaque;
 
-            ret = fn(child, opaque);
-            if (ret != 0) {
-                break;
+            if (!typename || object_dynamic_cast(child, typename)) {
+                ret = fn(child, opaque);
+                if (ret != 0) {
+                    break;
+                }
             }
             if (recurse) {
-                do_object_child_foreach(child, fn, opaque, true);
+                do_object_child_foreach(child, typename, fn, opaque, true);
             }
         }
     }
@@ -1014,14 +1016,28 @@ static int do_object_child_foreach(Object *obj,
 int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
                          void *opaque)
 {
-    return do_object_child_foreach(obj, fn, opaque, false);
+    return do_object_child_foreach(obj, NULL, fn, opaque, false);
 }
 
 int object_child_foreach_recursive(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque)
 {
-    return do_object_child_foreach(obj, fn, opaque, true);
+    return do_object_child_foreach(obj, NULL, fn, opaque, true);
+}
+
+int object_child_foreach_type(Object *obj, const char *typename,
+                              int (*fn)(Object *child, void *opaque),
+                              void *opaque)
+{
+    return do_object_child_foreach(obj, typename, fn, opaque, false);
+}
+
+int object_child_foreach_recursive_type(Object *obj, const char *typename,
+                                        int (*fn)(Object *child, void *opaque),
+                                        void *opaque)
+{
+    return do_object_child_foreach(obj, typename, fn, opaque, true);
 }
 
 static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)

On Wed, Oct 23, 2019 at 04:52:16PM +0200, Greg Kurz wrote:
> Calling a function for children of a certain type is a recurring pattern
> in the QEMU code base. In order to avoid the need to setup the same boiler
> plate again and again, introduce a variant of object_child_foreach() that
> only considers children of the given type.
> 
> Signed-off-by: Greg Kurz <groug@kaod.org>

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

> ---
>  include/qom/object.h |   35 +++++++++++++++++++++++++++++++++++
>  qom/object.c         |   30 +++++++++++++++++++++++-------
>  2 files changed, 58 insertions(+), 7 deletions(-)
> 
> diff --git a/include/qom/object.h b/include/qom/object.h
> index 128d00c77fd6..e9e3c2eae8ed 100644
> --- a/include/qom/object.h
> +++ b/include/qom/object.h
> @@ -1728,6 +1728,41 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
>  int object_child_foreach_recursive(Object *obj,
>                                     int (*fn)(Object *child, void *opaque),
>                                     void *opaque);
> +
> +/**
> + * object_child_foreach_type:
> + * @obj: the object whose children will be navigated
> + * @typename: the type of child objects to consider
> + * @fn: the iterator function to be called
> + * @opaque: an opaque value that will be passed to the iterator
> + *
> + * This is similar to object_child_foreach, but it only calls @fn for
> + * child objects of the give @typename.
> + *
> + * Returns: The last value returned by @fn, or 0 if there is no child of
> + * the given @typename.
> + */
> +int object_child_foreach_type(Object *obj, const char *typename,
> +                              int (*fn)(Object *child, void *opaque),
> +                              void *opaque);
> +
> +/**
> + * object_child_foreach_recursive_type:
> + * @obj: the object whose children will be navigated
> + * @typename: the type of child objects to consider
> + * @fn: the iterator function to be called
> + * @opaque: an opaque value that will be passed to the iterator
> + *
> + * This is similar to object_child_foreach_recursive, but it only calls
> + * @fn for child objects of the give @typename.
> + *
> + * Returns: The last value returned by @fn, or 0 if there is no child of
> + * the given @typename.
> + */
> +int object_child_foreach_recursive_type(Object *obj, const char *typename,
> +                                        int (*fn)(Object *child, void *opaque),
> +                                        void *opaque);
> +
>  /**
>   * container_get:
>   * @root: root of the #path, e.g., object_get_root()
> diff --git a/qom/object.c b/qom/object.c
> index 6fa9c619fac4..a2dec1261ff7 100644
> --- a/qom/object.c
> +++ b/qom/object.c
> @@ -986,7 +986,7 @@ void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
>      enumerating_types = false;
>  }
>  
> -static int do_object_child_foreach(Object *obj,
> +static int do_object_child_foreach(Object *obj, const char *typename,
>                                     int (*fn)(Object *child, void *opaque),
>                                     void *opaque, bool recurse)
>  {
> @@ -999,12 +999,14 @@ static int do_object_child_foreach(Object *obj,
>          if (object_property_is_child(prop)) {
>              Object *child = prop->opaque;
>  
> -            ret = fn(child, opaque);
> -            if (ret != 0) {
> -                break;
> +            if (!typename || object_dynamic_cast(child, typename)) {
> +                ret = fn(child, opaque);
> +                if (ret != 0) {
> +                    break;
> +                }
>              }
>              if (recurse) {
> -                do_object_child_foreach(child, fn, opaque, true);
> +                do_object_child_foreach(child, typename, fn, opaque, true);
>              }
>          }
>      }
> @@ -1014,14 +1016,28 @@ static int do_object_child_foreach(Object *obj,
>  int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
>                           void *opaque)
>  {
> -    return do_object_child_foreach(obj, fn, opaque, false);
> +    return do_object_child_foreach(obj, NULL, fn, opaque, false);
>  }
>  
>  int object_child_foreach_recursive(Object *obj,
>                                     int (*fn)(Object *child, void *opaque),
>                                     void *opaque)
>  {
> -    return do_object_child_foreach(obj, fn, opaque, true);
> +    return do_object_child_foreach(obj, NULL, fn, opaque, true);
> +}
> +
> +int object_child_foreach_type(Object *obj, const char *typename,
> +                              int (*fn)(Object *child, void *opaque),
> +                              void *opaque)
> +{
> +    return do_object_child_foreach(obj, typename, fn, opaque, false);
> +}
> +
> +int object_child_foreach_recursive_type(Object *obj, const char *typename,
> +                                        int (*fn)(Object *child, void *opaque),
> +                                        void *opaque)
> +{
> +    return do_object_child_foreach(obj, typename, fn, opaque, true);
>  }
>  
>  static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

On Thu, Oct 24, 2019 at 01:59:03PM +1100, David Gibson wrote:
> On Wed, Oct 23, 2019 at 04:52:16PM +0200, Greg Kurz wrote:
> > Calling a function for children of a certain type is a recurring pattern
> > in the QEMU code base. In order to avoid the need to setup the same boiler
> > plate again and again, introduce a variant of object_child_foreach() that
> > only considers children of the given type.
> > 
> > Signed-off-by: Greg Kurz <groug@kaod.org>
> 
> Reviewed-by: David Gibson <david@gibson.dropbear.id.au>

Actually.. a couuple of caveats on that.

Reading it again the name is potentially misleading it's "for each
object of given type" not "for each type"  So maybe
"object_child_foreach_of_type()".

Also, having created these, using them to simplify hmp_info_irq() and
hmp_info_pic() seems like a good idea.

> 
> > ---
> >  include/qom/object.h |   35 +++++++++++++++++++++++++++++++++++
> >  qom/object.c         |   30 +++++++++++++++++++++++-------
> >  2 files changed, 58 insertions(+), 7 deletions(-)
> > 
> > diff --git a/include/qom/object.h b/include/qom/object.h
> > index 128d00c77fd6..e9e3c2eae8ed 100644
> > --- a/include/qom/object.h
> > +++ b/include/qom/object.h
> > @@ -1728,6 +1728,41 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
> >  int object_child_foreach_recursive(Object *obj,
> >                                     int (*fn)(Object *child, void *opaque),
> >                                     void *opaque);
> > +
> > +/**
> > + * object_child_foreach_type:
> > + * @obj: the object whose children will be navigated
> > + * @typename: the type of child objects to consider
> > + * @fn: the iterator function to be called
> > + * @opaque: an opaque value that will be passed to the iterator
> > + *
> > + * This is similar to object_child_foreach, but it only calls @fn for
> > + * child objects of the give @typename.
> > + *
> > + * Returns: The last value returned by @fn, or 0 if there is no child of
> > + * the given @typename.
> > + */
> > +int object_child_foreach_type(Object *obj, const char *typename,
> > +                              int (*fn)(Object *child, void *opaque),
> > +                              void *opaque);
> > +
> > +/**
> > + * object_child_foreach_recursive_type:
> > + * @obj: the object whose children will be navigated
> > + * @typename: the type of child objects to consider
> > + * @fn: the iterator function to be called
> > + * @opaque: an opaque value that will be passed to the iterator
> > + *
> > + * This is similar to object_child_foreach_recursive, but it only calls
> > + * @fn for child objects of the give @typename.
> > + *
> > + * Returns: The last value returned by @fn, or 0 if there is no child of
> > + * the given @typename.
> > + */
> > +int object_child_foreach_recursive_type(Object *obj, const char *typename,
> > +                                        int (*fn)(Object *child, void *opaque),
> > +                                        void *opaque);
> > +
> >  /**
> >   * container_get:
> >   * @root: root of the #path, e.g., object_get_root()
> > diff --git a/qom/object.c b/qom/object.c
> > index 6fa9c619fac4..a2dec1261ff7 100644
> > --- a/qom/object.c
> > +++ b/qom/object.c
> > @@ -986,7 +986,7 @@ void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
> >      enumerating_types = false;
> >  }
> >  
> > -static int do_object_child_foreach(Object *obj,
> > +static int do_object_child_foreach(Object *obj, const char *typename,
> >                                     int (*fn)(Object *child, void *opaque),
> >                                     void *opaque, bool recurse)
> >  {
> > @@ -999,12 +999,14 @@ static int do_object_child_foreach(Object *obj,
> >          if (object_property_is_child(prop)) {
> >              Object *child = prop->opaque;
> >  
> > -            ret = fn(child, opaque);
> > -            if (ret != 0) {
> > -                break;
> > +            if (!typename || object_dynamic_cast(child, typename)) {
> > +                ret = fn(child, opaque);
> > +                if (ret != 0) {
> > +                    break;
> > +                }
> >              }
> >              if (recurse) {
> > -                do_object_child_foreach(child, fn, opaque, true);
> > +                do_object_child_foreach(child, typename, fn, opaque, true);
> >              }
> >          }
> >      }
> > @@ -1014,14 +1016,28 @@ static int do_object_child_foreach(Object *obj,
> >  int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
> >                           void *opaque)
> >  {
> > -    return do_object_child_foreach(obj, fn, opaque, false);
> > +    return do_object_child_foreach(obj, NULL, fn, opaque, false);
> >  }
> >  
> >  int object_child_foreach_recursive(Object *obj,
> >                                     int (*fn)(Object *child, void *opaque),
> >                                     void *opaque)
> >  {
> > -    return do_object_child_foreach(obj, fn, opaque, true);
> > +    return do_object_child_foreach(obj, NULL, fn, opaque, true);
> > +}
> > +
> > +int object_child_foreach_type(Object *obj, const char *typename,
> > +                              int (*fn)(Object *child, void *opaque),
> > +                              void *opaque)
> > +{
> > +    return do_object_child_foreach(obj, typename, fn, opaque, false);
> > +}
> > +
> > +int object_child_foreach_recursive_type(Object *obj, const char *typename,
> > +                                        int (*fn)(Object *child, void *opaque),
> > +                                        void *opaque)
> > +{
> > +    return do_object_child_foreach(obj, typename, fn, opaque, true);
> >  }
> >  
> >  static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
> > 
> 



-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

On Thu, 24 Oct 2019 14:07:15 +1100
David Gibson <david@gibson.dropbear.id.au> wrote:

> On Thu, Oct 24, 2019 at 01:59:03PM +1100, David Gibson wrote:
> > On Wed, Oct 23, 2019 at 04:52:16PM +0200, Greg Kurz wrote:
> > > Calling a function for children of a certain type is a recurring pattern
> > > in the QEMU code base. In order to avoid the need to setup the same boiler
> > > plate again and again, introduce a variant of object_child_foreach() that
> > > only considers children of the given type.
> > > 
> > > Signed-off-by: Greg Kurz <groug@kaod.org>
> > 
> > Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
> 
> Actually.. a couuple of caveats on that.
> 
> Reading it again the name is potentially misleading it's "for each
> object of given type" not "for each type"  So maybe
> "object_child_foreach_of_type()".
> 

Makes sense.

> Also, having created these, using them to simplify hmp_info_irq() and
> hmp_info_pic() seems like a good idea.
> 
> > 
> > > ---
> > >  include/qom/object.h |   35 +++++++++++++++++++++++++++++++++++
> > >  qom/object.c         |   30 +++++++++++++++++++++++-------
> > >  2 files changed, 58 insertions(+), 7 deletions(-)
> > > 
> > > diff --git a/include/qom/object.h b/include/qom/object.h
> > > index 128d00c77fd6..e9e3c2eae8ed 100644
> > > --- a/include/qom/object.h
> > > +++ b/include/qom/object.h
> > > @@ -1728,6 +1728,41 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
> > >  int object_child_foreach_recursive(Object *obj,
> > >                                     int (*fn)(Object *child, void *opaque),
> > >                                     void *opaque);
> > > +
> > > +/**
> > > + * object_child_foreach_type:
> > > + * @obj: the object whose children will be navigated
> > > + * @typename: the type of child objects to consider
> > > + * @fn: the iterator function to be called
> > > + * @opaque: an opaque value that will be passed to the iterator
> > > + *
> > > + * This is similar to object_child_foreach, but it only calls @fn for
> > > + * child objects of the give @typename.
> > > + *
> > > + * Returns: The last value returned by @fn, or 0 if there is no child of
> > > + * the given @typename.
> > > + */
> > > +int object_child_foreach_type(Object *obj, const char *typename,
> > > +                              int (*fn)(Object *child, void *opaque),
> > > +                              void *opaque);
> > > +
> > > +/**
> > > + * object_child_foreach_recursive_type:
> > > + * @obj: the object whose children will be navigated
> > > + * @typename: the type of child objects to consider
> > > + * @fn: the iterator function to be called
> > > + * @opaque: an opaque value that will be passed to the iterator
> > > + *
> > > + * This is similar to object_child_foreach_recursive, but it only calls
> > > + * @fn for child objects of the give @typename.
> > > + *
> > > + * Returns: The last value returned by @fn, or 0 if there is no child of
> > > + * the given @typename.
> > > + */
> > > +int object_child_foreach_recursive_type(Object *obj, const char *typename,
> > > +                                        int (*fn)(Object *child, void *opaque),
> > > +                                        void *opaque);
> > > +
> > >  /**
> > >   * container_get:
> > >   * @root: root of the #path, e.g., object_get_root()
> > > diff --git a/qom/object.c b/qom/object.c
> > > index 6fa9c619fac4..a2dec1261ff7 100644
> > > --- a/qom/object.c
> > > +++ b/qom/object.c
> > > @@ -986,7 +986,7 @@ void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
> > >      enumerating_types = false;
> > >  }
> > >  
> > > -static int do_object_child_foreach(Object *obj,
> > > +static int do_object_child_foreach(Object *obj, const char *typename,
> > >                                     int (*fn)(Object *child, void *opaque),
> > >                                     void *opaque, bool recurse)
> > >  {
> > > @@ -999,12 +999,14 @@ static int do_object_child_foreach(Object *obj,
> > >          if (object_property_is_child(prop)) {
> > >              Object *child = prop->opaque;
> > >  
> > > -            ret = fn(child, opaque);
> > > -            if (ret != 0) {
> > > -                break;
> > > +            if (!typename || object_dynamic_cast(child, typename)) {
> > > +                ret = fn(child, opaque);
> > > +                if (ret != 0) {
> > > +                    break;
> > > +                }
> > >              }
> > >              if (recurse) {
> > > -                do_object_child_foreach(child, fn, opaque, true);
> > > +                do_object_child_foreach(child, typename, fn, opaque, true);
> > >              }
> > >          }
> > >      }
> > > @@ -1014,14 +1016,28 @@ static int do_object_child_foreach(Object *obj,
> > >  int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque),
> > >                           void *opaque)
> > >  {
> > > -    return do_object_child_foreach(obj, fn, opaque, false);
> > > +    return do_object_child_foreach(obj, NULL, fn, opaque, false);
> > >  }
> > >  
> > >  int object_child_foreach_recursive(Object *obj,
> > >                                     int (*fn)(Object *child, void *opaque),
> > >                                     void *opaque)
> > >  {
> > > -    return do_object_child_foreach(obj, fn, opaque, true);
> > > +    return do_object_child_foreach(obj, NULL, fn, opaque, true);
> > > +}
> > > +
> > > +int object_child_foreach_type(Object *obj, const char *typename,
> > > +                              int (*fn)(Object *child, void *opaque),
> > > +                              void *opaque)
> > > +{
> > > +    return do_object_child_foreach(obj, typename, fn, opaque, false);
> > > +}
> > > +
> > > +int object_child_foreach_recursive_type(Object *obj, const char *typename,
> > > +                                        int (*fn)(Object *child, void *opaque),
> > > +                                        void *opaque)
> > > +{
> > > +    return do_object_child_foreach(obj, typename, fn, opaque, true);
> > >  }
> > >  
> > >  static void object_class_get_list_tramp(ObjectClass *klass, void *opaque)
> > > 
> > 
> 
> 
>