/* * Dealloc Visitor * * Copyright (C) 2012-2016 Red Hat, Inc. * Copyright IBM, Corp. 2011 * * Authors: * Michael Roth * * 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. * */ #include "qemu/osdep.h" #include "qapi/dealloc-visitor.h" #include "qemu/queue.h" #include "qemu-common.h" #include "qapi/qmp/types.h" #include "qapi/visitor-impl.h" typedef struct StackEntry { void *value; bool is_list_head; QTAILQ_ENTRY(StackEntry) node; } StackEntry; struct QapiDeallocVisitor { Visitor visitor; QTAILQ_HEAD(, StackEntry) stack; }; static QapiDeallocVisitor *to_qov(Visitor *v) { return container_of(v, QapiDeallocVisitor, visitor); } static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value) { StackEntry *e = g_malloc0(sizeof(*e)); e->value = value; /* see if we're just pushing a list head tracker */ if (value == NULL) { e->is_list_head = true; } QTAILQ_INSERT_HEAD(&qov->stack, e, node); } static void *qapi_dealloc_pop(QapiDeallocVisitor *qov) { StackEntry *e = QTAILQ_FIRST(&qov->stack); QObject *value; QTAILQ_REMOVE(&qov->stack, e, node); value = e->value; g_free(e); return value; } static void qapi_dealloc_start_struct(Visitor *v, const char *name, void **obj, size_t unused, Error **errp) { QapiDeallocVisitor *qov = to_qov(v); qapi_dealloc_push(qov, obj); } static void qapi_dealloc_end_struct(Visitor *v, Error **errp) { QapiDeallocVisitor *qov = to_qov(v); void **obj = qapi_dealloc_pop(qov); if (obj) { g_free(*obj); } } static void qapi_dealloc_start_implicit_struct(Visitor *v, void **obj, size_t size, Error **errp) { QapiDeallocVisitor *qov = to_qov(v); qapi_dealloc_push(qov, obj); } static void qapi_dealloc_end_implicit_struct(Visitor *v) { QapiDeallocVisitor *qov = to_qov(v); void **obj = qapi_dealloc_pop(qov); if (obj) { g_free(*obj); } } static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp) { QapiDeallocVisitor *qov = to_qov(v); qapi_dealloc_push(qov, NULL); } static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **listp) { GenericList *list = *listp; QapiDeallocVisitor *qov = to_qov(v); StackEntry *e = QTAILQ_FIRST(&qov->stack); if (e && e->is_list_head) { e->is_list_head = false; return list; } if (list) { list = list->next; g_free(*listp); return list; } return NULL; } static void qapi_dealloc_end_list(Visitor *v) { QapiDeallocVisitor *qov = to_qov(v); void *obj = qapi_dealloc_pop(qov); assert(obj == NULL); /* should've been list head tracker with no payload */ } static void qapi_dealloc_type_str(Visitor *v, const char *name, char **obj, Error **errp) { if (obj) { g_free(*obj); } } static void qapi_dealloc_type_int64(Visitor *v, const char *name, int64_t *obj, Error **errp) { } static void qapi_dealloc_type_uint64(Visitor *v, const char *name, uint64_t *obj, Error **errp) { } static void qapi_dealloc_type_bool(Visitor *v, const char *name, bool *obj, Error **errp) { } static void qapi_dealloc_type_number(Visitor *v, const char *name, double *obj, Error **errp) { } static void qapi_dealloc_type_anything(Visitor *v, const char *name, QObject **obj, Error **errp) { if (obj) { qobject_decref(*obj); } } static void qapi_dealloc_type_enum(Visitor *v, const char *name, int *obj, const char * const strings[], Error **errp) { } /* If there's no data present, the dealloc visitor has nothing to free. * Thus, indicate to visitor code that the subsequent union fields can * be skipped. This is not an error condition, since the cleanup of the * rest of an object can continue unhindered, so leave errp unset in * these cases. * * NOTE: In cases where we're attempting to deallocate an object that * may have missing fields, the field indicating the union type may * be missing. In such a case, it's possible we don't have enough * information to differentiate data_present == false from a case where * data *is* present but happens to be a scalar with a value of 0. * This is okay, since in the case of the dealloc visitor there's no * work that needs to done in either situation. * * The current inability in QAPI code to more thoroughly verify a union * type in such cases will likely need to be addressed if we wish to * implement this interface for other types of visitors in the future, * however. */ static bool qapi_dealloc_start_union(Visitor *v, bool data_present, Error **errp) { return data_present; } Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v) { return &v->visitor; } void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v) { g_free(v); } QapiDeallocVisitor *qapi_dealloc_visitor_new(void) { QapiDeallocVisitor *v; v = g_malloc0(sizeof(*v)); v->visitor.start_struct = qapi_dealloc_start_struct; v->visitor.end_struct = qapi_dealloc_end_struct; v->visitor.start_implicit_struct = qapi_dealloc_start_implicit_struct; v->visitor.end_implicit_struct = qapi_dealloc_end_implicit_struct; v->visitor.start_list = qapi_dealloc_start_list; v->visitor.next_list = qapi_dealloc_next_list; v->visitor.end_list = qapi_dealloc_end_list; v->visitor.type_enum = qapi_dealloc_type_enum; v->visitor.type_int64 = qapi_dealloc_type_int64; v->visitor.type_uint64 = qapi_dealloc_type_uint64; v->visitor.type_bool = qapi_dealloc_type_bool; v->visitor.type_str = qapi_dealloc_type_str; v->visitor.type_number = qapi_dealloc_type_number; v->visitor.type_any = qapi_dealloc_type_anything; v->visitor.start_union = qapi_dealloc_start_union; QTAILQ_INIT(&v->stack); return v; }