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/*
* Core Definitions for QAPI Visitor implementations
*
* Copyright (C) 2012-2016 Red Hat, Inc.
*
* Author: Paolo Bonizni <pbonzini@redhat.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#ifndef QAPI_VISITOR_IMPL_H
#define QAPI_VISITOR_IMPL_H
#include "qapi/visitor.h"
/*
* This file describes the callback interface for implementing a QAPI
* visitor. For the client interface, see visitor.h. When
* implementing the callbacks, it is easiest to declare a struct with
* 'Visitor visitor;' as the first member. A callback's contract
* matches the corresponding public functions' contract unless stated
* otherwise. In the comments below, some callbacks are marked "must
* be set for $TYPE visits to work"; if a visitor implementation omits
* that callback, it should also document that it is only useful for a
* subset of QAPI.
*/
/*
* There are four classes of visitors; setting the class determines
* how QAPI enums are visited, as well as what additional restrictions
* can be asserted. The values are intentionally chosen so as to
* permit some assertions based on whether a given bit is set (that
* is, some assertions apply to input and clone visitors, some
* assertions apply to output and clone visitors).
*/
typedef enum VisitorType {
VISITOR_INPUT = 1,
VISITOR_OUTPUT = 2,
VISITOR_CLONE = 3,
VISITOR_DEALLOC = 4,
} VisitorType;
struct Visitor
{
/*
* Only input visitors may fail!
*/
/* Must be set to visit structs */
bool (*start_struct)(Visitor *v, const char *name, void **obj,
size_t size, Error **errp);
/* Optional; intended for input visitors */
bool (*check_struct)(Visitor *v, Error **errp);
/* Must be set to visit structs */
void (*end_struct)(Visitor *v, void **obj);
/* Must be set; implementations may require @list to be non-null,
* but must document it. */
bool (*start_list)(Visitor *v, const char *name, GenericList **list,
size_t size, Error **errp);
/* Must be set */
GenericList *(*next_list)(Visitor *v, GenericList *tail, size_t size);
/* Optional; intended for input visitors */
bool (*check_list)(Visitor *v, Error **errp);
/* Must be set */
void (*end_list)(Visitor *v, void **list);
/* Must be set by input and clone visitors to visit alternates */
bool (*start_alternate)(Visitor *v, const char *name,
GenericAlternate **obj, size_t size,
Error **errp);
/* Optional */
void (*end_alternate)(Visitor *v, void **obj);
/* Must be set */
bool (*type_int64)(Visitor *v, const char *name, int64_t *obj,
Error **errp);
/* Must be set */
bool (*type_uint64)(Visitor *v, const char *name, uint64_t *obj,
Error **errp);
/* Optional; fallback is type_uint64() */
bool (*type_size)(Visitor *v, const char *name, uint64_t *obj,
Error **errp);
/* Must be set */
bool (*type_bool)(Visitor *v, const char *name, bool *obj, Error **errp);
/* Must be set */
bool (*type_str)(Visitor *v, const char *name, char **obj, Error **errp);
/* Must be set to visit numbers */
bool (*type_number)(Visitor *v, const char *name, double *obj,
Error **errp);
/* Must be set to visit arbitrary QTypes */
bool (*type_any)(Visitor *v, const char *name, QObject **obj,
Error **errp);
/* Must be set to visit explicit null values. */
bool (*type_null)(Visitor *v, const char *name, QNull **obj,
Error **errp);
/* Must be set for input visitors to visit structs, optional otherwise.
The core takes care of the return type in the public interface. */
void (*optional)(Visitor *v, const char *name, bool *present);
/* Optional */
bool (*policy_reject)(Visitor *v, const char *name,
unsigned special_features, Error **errp);
/* Optional */
bool (*policy_skip)(Visitor *v, const char *name,
unsigned special_features);
/* Must be set */
VisitorType type;
/* Optional */
struct CompatPolicy compat_policy;
/* Must be set for output visitors, optional otherwise. */
void (*complete)(Visitor *v, void *opaque);
/* Must be set */
void (*free)(Visitor *v);
};
#endif
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