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diff --git a/include/qom/object.h b/include/qom/object.h new file mode 100644 index 0000000000..ed1f47f050 --- /dev/null +++ b/include/qom/object.h @@ -0,0 +1,1003 @@ +/* + * 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 "object" + +/** + * 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; + +/** + * ObjectUnparent: + * @obj: the object that is being removed from the composition tree + * + * Called when an object is being removed from the QOM composition tree. + * The function should remove any backlinks from children objects to @obj. + */ +typedef void (ObjectUnparent)(Object *obj); + +/** + * ObjectFree: + * @obj: the object being freed + * + * Called when an object's last reference is removed. + */ +typedef void (ObjectFree)(void *obj); + +/** + * ObjectClass: + * + * The base for all classes. The only thing that #ObjectClass contains is an + * integer type handle. + */ +struct ObjectClass +{ + /*< private >*/ + Type type; + GSList *interfaces; + + ObjectUnparent *unparent; +}; + +/** + * 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; + ObjectFree *free; + 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_base_init: This function is called for all base classes after all + * parent class initialization has occurred, but before the class itself + * is initialized. This is the function to use to undo the effects of + * memcpy from the parent class to the descendents. + * @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, @class_base_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_base_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) + +/** + * InterfaceInfo: + * @type: The name of the interface. + * + * The information associated with an interface. + */ +struct InterfaceInfo { + const char *type; +}; + +/** + * 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; + /*< private >*/ + ObjectClass *concrete_class; +}; + +#define TYPE_INTERFACE "interface" + +/** + * INTERFACE_CLASS: + * @klass: class to cast from + * Returns: An #InterfaceClass or raise an error if cast is invalid + */ +#define INTERFACE_CLASS(klass) \ + OBJECT_CLASS_CHECK(InterfaceClass, klass, TYPE_INTERFACE) + +/** + * INTERFACE_CHECK: + * @interface: the type to return + * @obj: the object to convert to an interface + * @name: the interface type name + * + * Returns: @obj casted to @interface if cast is valid, otherwise raise error. + */ +#define INTERFACE_CHECK(interface, obj, name) \ + ((interface *)object_dynamic_cast_assert(OBJECT((obj)), (name))) + +/** + * 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_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); + +/** + * 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_parent: + * @klass: The class to obtain the parent for. + * + * Returns: The parent for @klass or %NULL if none. + */ +ObjectClass *object_class_get_parent(ObjectClass *klass); + +/** + * 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); + +/** + * object_class_by_name: + * @typename: The QOM typename to obtain the class for. + * + * Returns: The class for @typename or %NULL if not found. + */ +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); + +/** + * object_property_find: + * @obj: the object + * @name: the name of the property + * @errp: returns an error if this function fails + * + * Look up a property for an object and return its #ObjectProperty if found. + */ +ObjectProperty *object_property_find(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_resolve_path_component: + * @parent: the object in which to resolve the path + * @part: the component to resolve. + * + * This is similar to object_resolve_path with an absolute path, but it + * only resolves one element (@part) and takes the others from @parent. + * + * Returns: The resolved object or NULL on path lookup failure. + */ +Object *object_resolve_path_component(Object *parent, gchar *part); + +/** + * 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); + +/** + * object_property_add_bool: + * @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. + * @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 bool property using getters/setters. This function will add a + * property of type 'bool'. + */ +void object_property_add_bool(Object *obj, const char *name, + bool (*get)(Object *, struct Error **), + void (*set)(Object *, bool, struct Error **), + struct Error **errp); + +/** + * object_child_foreach: + * @obj: the object whose children will be navigated + * @fn: the iterator function to be called + * @opaque: an opaque value that will be passed to the iterator + * + * Call @fn passing each child of @obj and @opaque to it, until @fn returns + * non-zero. + * + * Returns: The last value returned by @fn, or 0 if there is no child. + */ +int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque), + void *opaque); + +/** + * container_get: + * @root: root of the #path, e.g., object_get_root() + * @path: path to the container + * + * Return a container object whose path is @path. Create more containers + * along the path if necessary. + * + * Returns: the container object. + */ +Object *container_get(Object *root, const char *path); + + +#endif |