/*
* QEMU Object Model
*
* Copyright IBM, Corp. 2011
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#ifndef QEMU_OBJECT_H
#define QEMU_OBJECT_H
#include <glib.h>
#include <stdint.h>
#include <stdbool.h>
#include "qemu-queue.h"
struct Visitor;
struct Error;
struct TypeImpl;
typedef struct TypeImpl *Type;
typedef struct ObjectClass ObjectClass;
typedef struct Object Object;
typedef struct TypeInfo TypeInfo;
typedef struct InterfaceClass InterfaceClass;
typedef struct InterfaceInfo InterfaceInfo;
#define TYPE_OBJECT NULL
/**
* SECTION:object.h
* @title:Base Object Type System
* @short_description: interfaces for creating new types and objects
*
* The QEMU Object Model provides a framework for registering user creatable
* types and instantiating objects from those types. QOM provides the following
* features:
*
* - System for dynamically registering types
* - Support for single-inheritance of types
* - Multiple inheritance of stateless interfaces
*
* <example>
* <title>Creating a minimal type</title>
* <programlisting>
* #include "qdev.h"
*
* #define TYPE_MY_DEVICE "my-device"
*
* // No new virtual functions: we can reuse the typedef for the
* // superclass.
* typedef DeviceClass MyDeviceClass;
* typedef struct MyDevice
* {
* DeviceState parent;
*
* int reg0, reg1, reg2;
* } MyDevice;
*
* static TypeInfo my_device_info = {
* .name = TYPE_MY_DEVICE,
* .parent = TYPE_DEVICE,
* .instance_size = sizeof(MyDevice),
* };
*
* static void my_device_register_types(void)
* {
* type_register_static(&my_device_info);
* }
*
* type_init(my_device_register_types)
* </programlisting>
* </example>
*
* In the above example, we create a simple type that is described by #TypeInfo.
* #TypeInfo describes information about the type including what it inherits
* from, the instance and class size, and constructor/destructor hooks.
*
* Every type has an #ObjectClass associated with it. #ObjectClass derivatives
* are instantiated dynamically but there is only ever one instance for any
* given type. The #ObjectClass typically holds a table of function pointers
* for the virtual methods implemented by this type.
*
* Using object_new(), a new #Object derivative will be instantiated. You can
* cast an #Object to a subclass (or base-class) type using
* object_dynamic_cast(). You typically want to define macro wrappers around
* OBJECT_CHECK() and OBJECT_CLASS_CHECK() to make it easier to convert to a
* specific type:
*
* <example>
* <title>Typecasting macros</title>
* <programlisting>
* #define MY_DEVICE_GET_CLASS(obj) \
* OBJECT_GET_CLASS(MyDeviceClass, obj, TYPE_MY_DEVICE)
* #define MY_DEVICE_CLASS(klass) \
* OBJECT_CLASS_CHECK(MyDeviceClass, klass, TYPE_MY_DEVICE)
* #define MY_DEVICE(obj) \
* OBJECT_CHECK(MyDevice, obj, TYPE_MY_DEVICE)
* </programlisting>
* </example>
*
* # Class Initialization #
*
* Before an object is initialized, the class for the object must be
* initialized. There is only one class object for all instance objects
* that is created lazily.
*
* Classes are initialized by first initializing any parent classes (if
* necessary). After the parent class object has initialized, it will be
* copied into the current class object and any additional storage in the
* class object is zero filled.
*
* The effect of this is that classes automatically inherit any virtual
* function pointers that the parent class has already initialized. All
* other fields will be zero filled.
*
* Once all of the parent classes have been initialized, #TypeInfo::class_init
* is called to let the class being instantiated provide default initialize for
* its virtual functions. Here is how the above example might be modified
* to introduce an overridden virtual function:
*
* <example>
* <title>Overriding a virtual function</title>
* <programlisting>
* #include "qdev.h"
*
* void my_device_class_init(ObjectClass *klass, void *class_data)
* {
* DeviceClass *dc = DEVICE_CLASS(klass);
* dc->reset = my_device_reset;
* }
*
* static TypeInfo my_device_info = {
* .name = TYPE_MY_DEVICE,
* .parent = TYPE_DEVICE,
* .instance_size = sizeof(MyDevice),
* .class_init = my_device_class_init,
* };
* </programlisting>
* </example>
*
* Introducing new virtual functions requires a class to define its own
* struct and to add a .class_size member to the TypeInfo. Each function
* will also have a wrapper to call it easily:
*
* <example>
* <title>Defining an abstract class</title>
* <programlisting>
* #include "qdev.h"
*
* typedef struct MyDeviceClass
* {
* DeviceClass parent;
*
* void (*frobnicate) (MyDevice *obj);
* } MyDeviceClass;
*
* static TypeInfo my_device_info = {
* .name = TYPE_MY_DEVICE,
* .parent = TYPE_DEVICE,
* .instance_size = sizeof(MyDevice),
* .abstract = true, // or set a default in my_device_class_init
* .class_size = sizeof(MyDeviceClass),
* };
*
* void my_device_frobnicate(MyDevice *obj)
* {
* MyDeviceClass *klass = MY_DEVICE_GET_CLASS(obj);
*
* klass->frobnicate(obj);
* }
* </programlisting>
* </example>
*
* # Interfaces #
*
* Interfaces allow a limited form of multiple inheritance. Instances are
* similar to normal types except for the fact that are only defined by
* their classes and never carry any state. You can dynamically cast an object
* to one of its #Interface types and vice versa.
*/
/**
* ObjectPropertyAccessor:
* @obj: the object that owns the property
* @v: the visitor that contains the property data
* @opaque: the object property opaque
* @name: the name of the property
* @errp: a pointer to an Error that is filled if getting/setting fails.
*
* Called when trying to get/set a property.
*/
typedef void (ObjectPropertyAccessor)(Object *obj,
struct Visitor *v,
void *opaque,
const char *name,
struct Error **errp);
/**
* ObjectPropertyRelease:
* @obj: the object that owns the property
* @name: the name of the property
* @opaque: the opaque registered with the property
*
* Called when a property is removed from a object.
*/
typedef void (ObjectPropertyRelease)(Object *obj,
const char *name,
void *opaque);
typedef struct ObjectProperty
{
gchar *name;
gchar *type;
ObjectPropertyAccessor *get;
ObjectPropertyAccessor *set;
ObjectPropertyRelease *release;
void *opaque;
QTAILQ_ENTRY(ObjectProperty) node;
} ObjectProperty;
/**
* ObjectClass:
*
* The base for all classes. The only thing that #ObjectClass contains is an
* integer type handle.
*/
struct ObjectClass
{
/*< private >*/
Type type;
};
/**
* Object:
*
* The base for all objects. The first member of this object is a pointer to
* a #ObjectClass. Since C guarantees that the first member of a structure
* always begins at byte 0 of that structure, as long as any sub-object places
* its parent as the first member, we can cast directly to a #Object.
*
* As a result, #Object contains a reference to the objects type as its
* first member. This allows identification of the real type of the object at
* run time.
*
* #Object also contains a list of #Interfaces that this object
* implements.
*/
struct Object
{
/*< private >*/
ObjectClass *class;
GSList *interfaces;
QTAILQ_HEAD(, ObjectProperty) properties;
uint32_t ref;
Object *parent;
};
/**
* TypeInfo:
* @name: The name of the type.
* @parent: The name of the parent type.
* @instance_size: The size of the object (derivative of #Object). If
* @instance_size is 0, then the size of the object will be the size of the
* parent object.
* @instance_init: This function is called to initialize an object. The parent
* class will have already been initialized so the type is only responsible
* for initializing its own members.
* @instance_finalize: This function is called during object destruction. This
* is called before the parent @instance_finalize function has been called.
* An object should only free the members that are unique to its type in this
* function.
* @abstract: If this field is true, then the class is considered abstract and
* cannot be directly instantiated.
* @class_size: The size of the class object (derivative of #ObjectClass)
* for this object. If @class_size is 0, then the size of the class will be
* assumed to be the size of the parent class. This allows a type to avoid
* implementing an explicit class type if they are not adding additional
* virtual functions.
* @class_init: This function is called after all parent class initialization
* has occurred to allow a class to set its default virtual method pointers.
* This is also the function to use to override virtual methods from a parent
* class.
* @class_finalize: This function is called during class destruction and is
* meant to release and dynamic parameters allocated by @class_init.
* @class_data: Data to pass to the @class_init and @class_finalize functions.
* This can be useful when building dynamic classes.
* @interfaces: The list of interfaces associated with this type. This
* should point to a static array that's terminated with a zero filled
* element.
*/
struct TypeInfo
{
const char *name;
const char *parent;
size_t instance_size;
void (*instance_init)(Object *obj);
void (*instance_finalize)(Object *obj);
bool abstract;
size_t class_size;
void (*class_init)(ObjectClass *klass, void *data);
void (*class_finalize)(ObjectClass *klass, void *data);
void *class_data;
InterfaceInfo *interfaces;
};
/**
* OBJECT:
* @obj: A derivative of #Object
*
* Converts an object to a #Object. Since all objects are #Objects,
* this function will always succeed.
*/
#define OBJECT(obj) \
((Object *)(obj))
/**
* OBJECT_CLASS:
* @class: A derivative of #ObjectClass.
*
* Converts a class to an #ObjectClass. Since all objects are #Objects,
* this function will always succeed.
*/
#define OBJECT_CLASS(class) \
((ObjectClass *)(class))
/**
* OBJECT_CHECK:
* @type: The C type to use for the return value.
* @obj: A derivative of @type to cast.
* @name: The QOM typename of @type
*
* A type safe version of @object_dynamic_cast_assert. Typically each class
* will define a macro based on this type to perform type safe dynamic_casts to
* this object type.
*
* If an invalid object is passed to this function, a run time assert will be
* generated.
*/
#define OBJECT_CHECK(type, obj, name) \
((type *)object_dynamic_cast_assert(OBJECT(obj), (name)))
/**
* OBJECT_CLASS_CHECK:
* @class: The C type to use for the return value.
* @obj: A derivative of @type to cast.
* @name: the QOM typename of @class.
*
* A type safe version of @object_class_dynamic_cast_assert. This macro is
* typically wrapped by each type to perform type safe casts of a class to a
* specific class type.
*/
#define OBJECT_CLASS_CHECK(class, obj, name) \
((class *)object_class_dynamic_cast_assert(OBJECT_CLASS(obj), (name)))
/**
* OBJECT_GET_CLASS:
* @class: The C type to use for the return value.
* @obj: The object to obtain the class for.
* @name: The QOM typename of @obj.
*
* This function will return a specific class for a given object. Its generally
* used by each type to provide a type safe macro to get a specific class type
* from an object.
*/
#define OBJECT_GET_CLASS(class, obj, name) \
OBJECT_CLASS_CHECK(class, object_get_class(OBJECT(obj)), name)
/**
* InterfaceClass:
* @parent_class: the base class
*
* The class for all interfaces. Subclasses of this class should only add
* virtual methods.
*/
struct InterfaceClass
{
ObjectClass parent_class;
};
/**
* InterfaceInfo:
* @type: The name of the interface.
* @interface_initfn: This method is called during class initialization and is
* used to initialize an interface associated with a class. This function
* should initialize any default virtual functions for a class and/or override
* virtual functions in a parent class.
*
* The information associated with an interface.
*/
struct InterfaceInfo
{
const char *type;
void (*interface_initfn)(ObjectClass *class, void *data);
};
#define TYPE_INTERFACE "interface"
/**
* object_new:
* @typename: The name of the type of the object to instantiate.
*
* This function will initialize a new object using heap allocated memory. This
* function should be paired with object_delete() to free the resources
* associated with the object.
*
* Returns: The newly allocated and instantiated object.
*/
Object *object_new(const char *typename);
/**
* object_new_with_type:
* @type: The type of the object to instantiate.
*
* This function will initialize a new object using heap allocated memory. This
* function should be paired with object_delete() to free the resources
* associated with the object.
*
* Returns: The newly allocated and instantiated object.
*/
Object *object_new_with_type(Type type);
/**
* object_delete:
* @obj: The object to free.
*
* Finalize an object and then free the memory associated with it. This should
* be paired with object_new() to free the resources associated with an object.
*/
void object_delete(Object *obj);
/**
* object_initialize_with_type:
* @obj: A pointer to the memory to be used for the object.
* @type: The type of the object to instantiate.
*
* This function will initialize an object. The memory for the object should
* have already been allocated.
*/
void object_initialize_with_type(void *data, Type type);
/**
* object_initialize:
* @obj: A pointer to the memory to be used for the object.
* @typename: The name of the type of the object to instantiate.
*
* This function will initialize an object. The memory for the object should
* have already been allocated.
*/
void object_initialize(void *obj, const char *typename);
/**
* object_finalize:
* @obj: The object to finalize.
*
* This function destroys and object without freeing the memory associated with
* it.
*/
void object_finalize(void *obj);
/**
* object_dynamic_cast:
* @obj: The object to cast.
* @typename: The @typename to cast to.
*
* This function will determine if @obj is-a @typename. @obj can refer to an
* object or an interface associated with an object.
*
* Returns: This function returns @obj on success or #NULL on failure.
*/
Object *object_dynamic_cast(Object *obj, const char *typename);
/**
* object_dynamic_cast_assert:
*
* See object_dynamic_cast() for a description of the parameters of this
* function. The only difference in behavior is that this function asserts
* instead of returning #NULL on failure.
*/
Object *object_dynamic_cast_assert(Object *obj, const char *typename);
/**
* object_get_class:
* @obj: A derivative of #Object
*
* Returns: The #ObjectClass of the type associated with @obj.
*/
ObjectClass *object_get_class(Object *obj);
/**
* object_get_typename:
* @obj: A derivative of #Object.
*
* Returns: The QOM typename of @obj.
*/
const char *object_get_typename(Object *obj);
/**
* type_register_static:
* @info: The #TypeInfo of the new type.
*
* @info and all of the strings it points to should exist for the life time
* that the type is registered.
*
* Returns: 0 on failure, the new #Type on success.
*/
Type type_register_static(const TypeInfo *info);
#define type_register_static_alias(info, name) do { } while (0)
/**
* type_register:
* @info: The #TypeInfo of the new type
*
* Unlike type_register_static(), this call does not require @info or its
* string members to continue to exist after the call returns.
*
* Returns: 0 on failure, the new #Type on success.
*/
Type type_register(const TypeInfo *info);
/**
* object_class_dynamic_cast_assert:
* @klass: The #ObjectClass to attempt to cast.
* @typename: The QOM typename of the class to cast to.
*
* Returns: This function always returns @klass and asserts on failure.
*/
ObjectClass *object_class_dynamic_cast_assert(ObjectClass *klass,
const char *typename);
ObjectClass *object_class_dynamic_cast(ObjectClass *klass,
const char *typename);
/**
* object_class_get_name:
* @klass: The class to obtain the QOM typename for.
*
* Returns: The QOM typename for @klass.
*/
const char *object_class_get_name(ObjectClass *klass);
ObjectClass *object_class_by_name(const char *typename);
void object_class_foreach(void (*fn)(ObjectClass *klass, void *opaque),
const char *implements_type, bool include_abstract,
void *opaque);
/**
* object_class_get_list:
* @implements_type: The type to filter for, including its derivatives.
* @include_abstract: Whether to include abstract classes.
*
* Returns: A singly-linked list of the classes in reverse hashtable order.
*/
GSList *object_class_get_list(const char *implements_type,
bool include_abstract);
/**
* object_ref:
* @obj: the object
*
* Increase the reference count of a object. A object cannot be freed as long
* as its reference count is greater than zero.
*/
void object_ref(Object *obj);
/**
* qdef_unref:
* @obj: the object
*
* Decrease the reference count of a object. A object cannot be freed as long
* as its reference count is greater than zero.
*/
void object_unref(Object *obj);
/**
* object_property_add:
* @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 'link<virtio-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.
* @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(Object *obj, const char *name, const char *type,
ObjectPropertyAccessor *get,
ObjectPropertyAccessor *set,
ObjectPropertyRelease *release,
void *opaque, struct Error **errp);
void object_property_del(Object *obj, const char *name, struct Error **errp);
void object_unparent(Object *obj);
/**
* object_property_get:
* @obj: the object
* @v: the visitor that will receive the property value. This should be an
* Output visitor and the data will be written with @name as the name.
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Reads a property from a object.
*/
void object_property_get(Object *obj, struct Visitor *v, const char *name,
struct Error **errp);
/**
* object_property_set_str:
* @value: the value to be written to the property
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Writes a string value to a property.
*/
void object_property_set_str(Object *obj, const char *value,
const char *name, struct Error **errp);
/**
* object_property_get_str:
* @obj: the object
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Returns: the value of the property, converted to a C string, or NULL if
* an error occurs (including when the property value is not a string).
* The caller should free the string.
*/
char *object_property_get_str(Object *obj, const char *name,
struct Error **errp);
/**
* object_property_set_link:
* @value: the value to be written to the property
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Writes an object's canonical path to a property.
*/
void object_property_set_link(Object *obj, Object *value,
const char *name, struct Error **errp);
/**
* object_property_get_link:
* @obj: the object
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Returns: the value of the property, resolved from a path to an Object,
* or NULL if an error occurs (including when the property value is not a
* string or not a valid object path).
*/
Object *object_property_get_link(Object *obj, const char *name,
struct Error **errp);
/**
* object_property_set_bool:
* @value: the value to be written to the property
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Writes a bool value to a property.
*/
void object_property_set_bool(Object *obj, bool value,
const char *name, struct Error **errp);
/**
* object_property_get_bool:
* @obj: the object
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Returns: the value of the property, converted to a boolean, or NULL if
* an error occurs (including when the property value is not a bool).
*/
bool object_property_get_bool(Object *obj, const char *name,
struct Error **errp);
/**
* object_property_set_int:
* @value: the value to be written to the property
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Writes an integer value to a property.
*/
void object_property_set_int(Object *obj, int64_t value,
const char *name, struct Error **errp);
/**
* object_property_get_int:
* @obj: the object
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Returns: the value of the property, converted to an integer, or NULL if
* an error occurs (including when the property value is not an integer).
*/
int64_t object_property_get_int(Object *obj, const char *name,
struct Error **errp);
/**
* object_property_set:
* @obj: the object
* @v: the visitor that will be used to write the property value. This should
* be an Input visitor and the data will be first read with @name as the
* name and then written as the property value.
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Writes a property to a object.
*/
void object_property_set(Object *obj, struct Visitor *v, const char *name,
struct Error **errp);
/**
* object_property_parse:
* @obj: the object
* @string: the string that will be used to parse the property value.
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Parses a string and writes the result into a property of an object.
*/
void object_property_parse(Object *obj, const char *string,
const char *name, struct Error **errp);
/**
* object_property_print:
* @obj: the object
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Returns a string representation of the value of the property. The
* caller shall free the string.
*/
char *object_property_print(Object *obj, const char *name,
struct Error **errp);
/**
* object_property_get_type:
* @obj: the object
* @name: the name of the property
* @errp: returns an error if this function fails
*
* Returns: The type name of the property.
*/
const char *object_property_get_type(Object *obj, const char *name,
struct Error **errp);
/**
* object_get_root:
*
* Returns: the root object of the composition tree
*/
Object *object_get_root(void);
/**
* object_get_canonical_path:
*
* Returns: The canonical path for a object. This is the path within the
* composition tree starting from the root.
*/
gchar *object_get_canonical_path(Object *obj);
/**
* object_resolve_path:
* @path: the path to resolve
* @ambiguous: returns true if the path resolution failed because of an
* ambiguous match
*
* There are two types of supported paths--absolute paths and partial paths.
*
* Absolute paths are derived from the root object and can follow child<> or
* link<> properties. Since they can follow link<> properties, they can be
* arbitrarily long. Absolute paths look like absolute filenames and are
* prefixed with a leading slash.
*
* Partial paths look like relative filenames. They do not begin with a
* prefix. The matching rules for partial paths are subtle but designed to make
* specifying objects easy. At each level of the composition tree, the partial
* path is matched as an absolute path. The first match is not returned. At
* least two matches are searched for. A successful result is only returned if
* only one match is found. If more than one match is found, a flag is
* returned to indicate that the match was ambiguous.
*
* Returns: The matched object or NULL on path lookup failure.
*/
Object *object_resolve_path(const char *path, bool *ambiguous);
/**
* object_resolve_path_type:
* @path: the path to resolve
* @typename: the type to look for.
* @ambiguous: returns true if the path resolution failed because of an
* ambiguous match
*
* This is similar to object_resolve_path. However, when looking for a
* partial path only matches that implement the given type are considered.
* This restricts the search and avoids spuriously flagging matches as
* ambiguous.
*
* For both partial and absolute paths, the return value goes through
* a dynamic cast to @typename. This is important if either the link,
* or the typename itself are of interface types.
*
* Returns: The matched object or NULL on path lookup failure.
*/
Object *object_resolve_path_type(const char *path, const char *typename,
bool *ambiguous);
/**
* object_property_add_child:
* @obj: the object to add a property to
* @name: the name of the property
* @child: the child object
* @errp: if an error occurs, a pointer to an area to store the area
*
* Child properties form the composition tree. All objects need to be a child
* of another object. Objects can only be a child of one object.
*
* There is no way for a child to determine what its parent is. It is not
* a bidirectional relationship. This is by design.
*
* The value of a child property as a C string will be the child object's
* canonical path. It can be retrieved using object_property_get_str().
* The child object itself can be retrieved using object_property_get_link().
*/
void object_property_add_child(Object *obj, const char *name,
Object *child, struct Error **errp);
/**
* object_property_add_link:
* @obj: the object to add a property to
* @name: the name of the property
* @type: the qobj type of the link
* @child: a pointer to where the link object reference is stored
* @errp: if an error occurs, a pointer to an area to store the area
*
* Links establish relationships between objects. Links are unidirectional
* although two links can be combined to form a bidirectional relationship
* between objects.
*
* Links form the graph in the object model.
*/
void object_property_add_link(Object *obj, const char *name,
const char *type, Object **child,
struct Error **errp);
/**
* object_property_add_str:
* @obj: the object to add a property to
* @name: the name of the property
* @get: the getter or NULL if the property is write-only. This function must
* return a string to be freed by g_free().
* @set: the setter or NULL if the property is read-only
* @errp: if an error occurs, a pointer to an area to store the error
*
* Add a string property using getters/setters. This function will add a
* property of type 'string'.
*/
void object_property_add_str(Object *obj, const char *name,
char *(*get)(Object *, struct Error **),
void (*set)(Object *, const char *, struct Error **),
struct Error **errp);
#endif
