Commit Graph

142 Commits

Author SHA1 Message Date
Cao jin
b30d805464 qom/object: fix 2 comment typos
Also change the misleading definition of macro OBJECT_CLASS_CHECK

Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2015-11-06 15:42:38 +03:00
Peter Crosthwaite
d714b8de77 qom: Add recursive version of object_child_for_each
Useful for iterating through an entire QOM subtree.

Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Tested-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
Message-id: 1441383782-24378-2-git-send-email-peter.maydell@linaro.org
2015-09-08 17:38:43 +01:00
Daniel P. Berrange
a3590dacce qom: Don't pass string table to object_get_enum() function
Now that properties can be explicitly registered as an enum
type, there is no need to pass the string table to the
object_get_enum() function. The object property registration
already has a pointer to the string table.

In changing this method signature, the hostmem backend object
has to be converted to use the new enum property registration
code, which simplifies it somewhat.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-06-19 18:42:48 +02:00
Daniel P. Berrange
a8e3fbedc8 qom: Add an object_property_add_enum() helper function
A QOM property can be parsed as enum using the visit_type_enum()
helper function, but this forces callers to use the more complex
generic object_property_add() method when registering it. It
also requires that users of that object have access to the
string map when they want to read the property value.

This patch introduces a specialized object_property_add_enum()
method which simplifies the use of enum properties, so the
setters/getters directly get passed the int value.

  typedef enum {
     MYDEV_TYPE_FROG,
     MYDEV_TYPE_ALLIGATOR,
     MYDEV_TYPE_PLATYPUS,

     MYDEV_TYPE_LAST
  } MyDevType;

Then provide a table of enum <-> string mappings

  static const char *const mydevtypemap[MYDEV_TYPE_LAST + 1] = {
     [MYDEV_TYPE_FROG] = "frog",
     [MYDEV_TYPE_ALLIGATOR] = "alligator",
     [MYDEV_TYPE_PLATYPUS] = "platypus",
     [MYDEV_TYPE_LAST] = NULL,
  };

Assuming an object struct of

   typedef struct {
      Object parent_obj;
      MyDevType devtype;
      ...other fields...
   } MyDev;

The property can then be registered as follows:

   static int mydev_prop_get_devtype(Object *obj,
                                     Error **errp G_GNUC_UNUSED)
   {
       MyDev *dev = MYDEV(obj);

       return dev->devtype;
   }

   static void mydev_prop_set_devtype(Object *obj,
                                      int value,
                                      Error **errp G_GNUC_UNUSED)
   {
       MyDev *dev = MYDEV(obj);

       dev->devtype = value;
   }

   object_property_add_enum(obj, "devtype",
                            mydevtypemap, "MyDevType",
                            mydev_prop_get_devtype,
                            mydev_prop_set_devtype,
                            NULL);

Note there is no need to check the range of 'value' in
the setter, because the string->enum conversion code will
have already done that and reported an error as required.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-06-19 18:42:18 +02:00
Daniel P. Berrange
2e4450ff43 qom: Make enum string tables const-correct
The enum string table parameters in various QOM/QAPI methods
are declared 'const char *strings[]'. This results in const
warnings if passed a variable that was declared as

   static const char * const strings[] = { .... };

Add the extra const annotation to the parameters, since
neither the string elements, nor the array itself should
ever be modified.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-06-19 18:42:18 +02:00
Daniel P. Berrange
a31bdae5a7 qom: Add object_new_with_props() / object_new_withpropv() helpers
It is reasonably common to want to create an object, set a
number of properties, register it in the hierarchy and then
mark it as complete (if a user creatable type). This requires
quite a lot of error prone, verbose, boilerplate code to achieve.

First a pair of functions object_set_props() / object_set_propv()
are added which allow for a list of objects to be set in
one single API call.

Then object_new_with_props() / object_new_with_propv() constructors
are added which simplify the sequence of calls to create an
object, populate properties, register in the object composition
tree and mark the object complete, into a single method call.

Usage would be:

   Error *err = NULL;
   Object *obj;
   obj = object_new_with_propv(TYPE_MEMORY_BACKEND_FILE,
                               object_get_objects_root(),
                               "hostmem0",
                               &err,
                               "share", "yes",
                               "mem-path", "/dev/shm/somefile",
                               "prealloc", "yes",
                               "size", "1048576",
                               NULL);

Note all property values are passed in string form and will
be parsed into their required data types, using normal QOM
semantics for parsing from string format.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-06-19 18:42:18 +02:00
Daniel P. Berrange
bc2256c4ae qom: Add helper function for getting user objects root
Add object_get_objects_root() function which is a convenience for
obtaining the Object * located at /objects in the object
composition tree. Convert existing code over to use the new
API where appropriate.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-06-19 18:40:00 +02:00
Paolo Bonzini
fb9e7e334b qom: add object_property_add_const_link
Suggested-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-06-05 17:36:39 +02:00
David Gibson
8e099d14f5 Generalize QOM publishing of date and time from mc146818rtc.c
The mc146818rtc driver exposes the current RTC date and time via the "date"
property in QOM (which is also aliased to the machine's "rtc-time"
property).  Currently it uses a custom visitor function rtc_get_date to
do this.

This patch introduces new helpers to the QOM core to expose struct tm
valued properties via a getter function, so that this functionality can be
more easily duplicated in other RTC implementations.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
2015-03-09 14:59:55 +01:00
Zhoujian
f824e8ed03 qom: Fix typo, 'my_class_init' -> 'derived_class_init'
Signed-off-by: Zhoujian <jianjay.zhou@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2015-02-16 15:07:09 +01:00
Gonglei
8074264203 qom: Add description field in ObjectProperty struct
The descriptions can serve as documentation in the code,
and they can be used to provide better help.

Copy property descriptions when copying alias properties.

Cc: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-10-15 05:03:15 +02:00
Paolo Bonzini
64607d0881 qom: add a generic mechanism to resolve paths
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.  This fixes aliases of link properties.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2014-07-01 10:17:48 +02:00
Stefan Hajnoczi
ef7c7ff6d4 qom: add object_property_add_alias()
Sometimes an object needs to present a property which is actually on
another object, or it needs to provide an alias name for an existing
property.

Examples:
  a.foo -> b.foo
  a.old_name -> a.new_name

The new object_property_add_alias() API allows objects to alias a
property on the same object or another object.  The source and target
names can be different.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
2014-07-01 09:15:02 +02:00
Hu Tao
1f21772db0 qom: introduce object_property_get_enum and object_property_get_uint16List
Signed-off-by: Hu Tao <hutao@cn.fujitsu.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2014-06-19 18:44:19 +03:00
Stefan Hajnoczi
39f72ef94b qom: Add check() argument to object_property_add_link()
There are currently three types of object_property_add_link() callers:

1. The link property may be set at any time.
2. The link property of a DeviceState instance may only be set before
   realize.
3. The link property may never be set, it is read-only.

Something similar can already be achieved with
object_property_add_str()'s set() argument.  Follow its example and add
a check() argument to object_property_add_link().

Also provide default check() functions for case #1 and #2.  Case #3 is
covered by passing a NULL function pointer.

Cc: Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
[AF: Tweaked documentation comment]
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-19 22:23:13 +01:00
Stefan Hajnoczi
9561fda8d9 qom: Make QOM link property unref optional
Some object_property_add_link() callers expect property deletion to
unref the link property object.  Other callers expect to manage the
refcount themselves.  The former are currently broken and therefore leak
the link property object.

This patch adds a flags argument to object_property_add_link() so the
caller can specify which refcount behavior they require.  The new
OBJ_PROP_LINK_UNREF_ON_RELEASE flag causes the link pointer to be
unreferenced when the property is deleted.

This fixes refcount leaks in qdev.c, xilinx_axidma.c, xilinx_axienet.c,
s390-virtio-bus.c, virtio-pci.c, virtio-rng.c, and ui/console.c.

Rationale for refcount behavior:

 * hw/core/qdev.c
   - bus children are explicitly unreferenced, don't interfere
   - parent_bus is essentially a read-only property that doesn't hold a
     refcount, don't unref
   - hotplug_handler is leaked, do unref

 * hw/dma/xilinx_axidma.c
   - rx stream "dma" links are set using set_link, therefore they
     need unref
   - tx streams are set using set_link, therefore they need unref

 * hw/net/xilinx_axienet.c
   - same reasoning as hw/dma/xilinx_axidma.c

 * hw/pcmcia/pxa2xx.c
   - pxa2xx bypasses set_link and therefore does not use refcounts

 * hw/s390x/s390-virtio-bus.c
 * hw/virtio/virtio-pci.c
 * hw/virtio/virtio-rng.c
 * ui/console.c
   - set_link is used and there is no explicit unref, do unref

Cc: Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-03-19 22:05:20 +01:00
Stefan Hajnoczi
11f590b1a2 object: add object_get_canonical_path_component()
It is often useful to find an object's child property name.  Also use
this new function to simplify the implementation of
object_get_canonical_path().

Reviewed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-03-13 14:23:27 +01:00
Paolo Bonzini
0b7593e085 qapi: Add human mode to StringOutputVisitor
This will be used by "info qtree".  For numbers it prints both the
decimal and hex values.  For sizes it rounds to the nearest power
of 2^10.  For strings, it puts quotes around the string and separates
NULL and empty string.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2014-02-14 21:12:03 +01:00
Paolo Bonzini
b061dc41f6 qom: Do not register interface "types" in the type table and fix names
There should be no need to look up nor enumerate the interface "types",
whose "classes" are really just vtables.  Just create the types and
add them to the interface list of the parent type.

Interfaces not registering their type anymore means that accessing
superclass::interface by type name will fail when initializing
subclass::interface.  Thus, we need to pre-initialize the subclass's
parent_type field before calling type_initialize.  Apart from this, the
interface "types" should never be used and thus it is harmless to leave
them out of the hashtable.

Further, the interface types had a bug with interfaces that are
inherited from a superclass:  The implementation type name was wrong
(for example it was subclass::superclass::interface rather than
just subclass::interface).  This patch fixes this as well.

Reported-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-12-24 17:27:17 +01:00
Peter Crosthwaite
0ab4c94c84 qom: Split out object and class caches
The object-cast and class-cast caches cannot be shared because class
caching is conditional on the target type not being an interface and
object caching is unconditional. Leads to a bug when a class cast
to an interface follows an object cast to the same interface type:

FooObject = FOO(obj);
FooClass = FOO_GET_CLASS(obj);

Where TYPE_FOO is an interface. The first (object) cast will be
successful and cache the casting result (i.e. TYPE_FOO will be cached).
The second (class) cast will then check the shared cast cache
and register a hit. The issue is, when a class cast hits in the cache
it just returns a pointer cast of the input class (i.e. the concrete
class).

When casting to an interface, the cast itself must return the
interface class, not the concrete class. The implementation of class
cast caching already ensures that the returned cast result is only
a pointer cast before caching. The object cast logic however does
not have this check.

Resolve by just splitting the object and class caches.

Cc: qemu-stable@nongnu.org
Signed-off-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Tested-by: Nathan Rossi <nathan.rossi@xilinx.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-12-24 17:27:17 +01:00
Michael S. Tsirkin
a25ebcacdd qom: Fix pointer to int property helpers' documentation
Relocate to alongside the other object_property_add_* helpers while at it.

Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-11-05 18:06:51 +01:00
Michael S. Tsirkin
e732ea6387 qom: add pointer to int property helpers
Make it easy to add read-only helpers for simple
integer properties in memory.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-10-14 17:46:00 +03:00
Michael S. Tsirkin
e82df24873 qom: cleanup struct Error references
now that a typedef for struct Error is available,
use it in qom/object.h to match coding style rules.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Tested-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Tested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-10-14 17:45:16 +03:00
Igor Mammedov
008e05662a cleanup object.h: include error.h directly
qapi/error.h is simple enough to be included in qom/object.h
direcly and prepares qom/object.h to use Error typedef.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2013-10-14 17:11:45 +03:00
Andreas Färber
5b9237f67c qom: Assert instance size in object_initialize_with_type()
This catches objects initializing beyond allocated memory, e.g.,
when subtypes get extended with instance state of their own.

Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-08-30 21:15:44 +02:00
Andreas Färber
213f0c4f61 qom: Pass available size to object_initialize()
To be passed on to object_initialize_with_type().

Acked-by: Cornelia Huck <cornelia.huck@de.ibm.com> (virtio-ccw)
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-08-30 21:15:44 +02:00
Andreas Färber
53caad9a31 qom: Fix object_initialize_with_type() argument name in documentation
@obj -> @data.

Reviewed-by: Wenchao Xia <xiawenc@linux.vnet.ibm.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-08-30 20:14:38 +02:00
Peter Chubb
70392912ed object: Fix typo in qom/object.h
There's been a cut-and-paste error, it looks like, in the documentation
in qom/object.h.

Signed-off-by: Peter Chubb <peter.chubb@nicta.com.au>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-08-30 20:14:37 +02:00
Eduardo Habkost
8231c2dd22 qom: Introduce instance_post_init hook
This will allow classes to specify a function to be called after all
instance_init functions were called.

This will be used by DeviceState to call qdev_prop_set_globals() at the
right moment.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
2013-08-16 18:44:33 +02:00
Anthony Liguori
035873283b qom: aggressively optimize qom casting
This patch adds a small typename cache to ObjectClass.  This allows
caching positive casts within each ObjectClass.  Benchmarking a
PPC workload provided by Aurelien, this patch eliminates every
single g_hash_table_lookup() happening during the benchmark (which
was about 2 million per-second).

With this patch applied, I get exactly the same performance (within
the margin of error) as with --disable-qom-cast-debug.

N.B. it's safe to cache typenames only from the _assert() macros
because they are always called with string literals.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-13 15:27:18 -05:00
Paolo Bonzini
3556c233d9 qom: allow turning cast debugging off
Cast debugging can have a substantial cost (20% or more).  Instead of adding
special-cased "fast casts" in the hot paths, we can just disable it in
releases.  The tracing facilities we just added make it easier to analyze
those problems that cast debugging would reveal.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1368188203-3407-7-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-13 09:52:06 -05:00
Paolo Bonzini
be17f18b8c qom: pass file/line/function to asserting casts
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1368188203-3407-5-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-13 09:52:06 -05:00
Paolo Bonzini
33bc94eb20 qom: improve documentation of cast functions
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1368188203-3407-2-git-send-email-pbonzini@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-05-13 09:52:05 -05:00
Peter Maydell
085d813407 Fix typos and misspellings
Fix various typos and misspellings. The bulk of these were found with
codespell.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-03-22 13:25:07 +01:00
Paolo Bonzini
b76facc35b qom: remove object_delete
This is now unused.  Document the initial reference count of an object
and when it will be freed/finalized.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-01 15:53:11 -06:00
Paolo Bonzini
6c232d2ffb qom: document reference counting of link properties
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-02-01 15:53:10 -06:00
Andreas Färber
1786237894 qom: Introduce object_class_is_abstract()
This lets a caller check if an ObjectClass as returned by, e.g.,
object_class_by_name() is instantiatable.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Cc: Anthony Liguori <anthony@codemonkey.ws>
2013-01-27 23:33:34 +01:00
Andreas Färber
782beb5239 qom: Extend documentation on QOM method concepts
Add a documentation section "Methods" and discuss among others how to
handle overriding virtual methods.

Clarify DeviceClass::realize documentation and refer to the above.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-01-17 07:33:16 -06:00
Andreas Färber
3e84b48321 qom: Make object_resolve_path_component() path argument const
A usage with a hardcoded partial path such as

  object_resolve_path_component(obj, "foo")

is totally valid but currently leads to a compilation error. Fix this.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-01-15 10:54:23 +01:00
Andreas Färber
8c43a6f05d Make all static TypeInfos const
Since 39bffca203 (qdev: register all
types natively through QEMU Object Model), TypeInfo as used in
the common, non-iterative pattern is no longer amended with information
and should therefore be const.

Fix the documented QOM examples:

 sed -i 's/static TypeInfo/static const TypeInfo/g' include/qom/object.h

Since frequently the wrong examples are being copied by contributors of
new devices, fix all types in the tree:

 sed -i 's/^static TypeInfo/static const TypeInfo/g' */*.c
 sed -i 's/^static TypeInfo/static const TypeInfo/g' */*/*.c

This also avoids to piggy-back these changes onto real functional
changes or other refactorings.

Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
2013-01-10 15:11:53 -06:00
Paolo Bonzini
1de7afc984 misc: move include files to include/qemu/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:32:39 +01:00
Paolo Bonzini
14cccb6185 qom: move include files to include/qom/
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19 08:31:32 +01:00