qom: move include files to include/qom/

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 1003 insertions, 0 deletions

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