virtio-scsi: work around bug in old BIOSes
[qemu.git] / qapi / qapi-dealloc-visitor.c
1 /*
2 * Dealloc Visitor
3 *
4 * Copyright IBM, Corp. 2011
5 *
6 * Authors:
7 * Michael Roth <mdroth@linux.vnet.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
10 * See the COPYING.LIB file in the top-level directory.
11 *
12 */
13
14 #include "qapi/dealloc-visitor.h"
15 #include "qemu/queue.h"
16 #include "qemu-common.h"
17 #include "qapi/qmp/types.h"
18 #include "qapi/visitor-impl.h"
19
20 typedef struct StackEntry
21 {
22 void *value;
23 bool is_list_head;
24 QTAILQ_ENTRY(StackEntry) node;
25 } StackEntry;
26
27 struct QapiDeallocVisitor
28 {
29 Visitor visitor;
30 QTAILQ_HEAD(, StackEntry) stack;
31 bool is_list_head;
32 };
33
34 static QapiDeallocVisitor *to_qov(Visitor *v)
35 {
36 return container_of(v, QapiDeallocVisitor, visitor);
37 }
38
39 static void qapi_dealloc_push(QapiDeallocVisitor *qov, void *value)
40 {
41 StackEntry *e = g_malloc0(sizeof(*e));
42
43 e->value = value;
44
45 /* see if we're just pushing a list head tracker */
46 if (value == NULL) {
47 e->is_list_head = true;
48 }
49 QTAILQ_INSERT_HEAD(&qov->stack, e, node);
50 }
51
52 static void *qapi_dealloc_pop(QapiDeallocVisitor *qov)
53 {
54 StackEntry *e = QTAILQ_FIRST(&qov->stack);
55 QObject *value;
56 QTAILQ_REMOVE(&qov->stack, e, node);
57 value = e->value;
58 g_free(e);
59 return value;
60 }
61
62 static void qapi_dealloc_start_struct(Visitor *v, void **obj, const char *kind,
63 const char *name, size_t unused,
64 Error **errp)
65 {
66 QapiDeallocVisitor *qov = to_qov(v);
67 qapi_dealloc_push(qov, obj);
68 }
69
70 static void qapi_dealloc_end_struct(Visitor *v, Error **errp)
71 {
72 QapiDeallocVisitor *qov = to_qov(v);
73 void **obj = qapi_dealloc_pop(qov);
74 if (obj) {
75 g_free(*obj);
76 }
77 }
78
79 static void qapi_dealloc_start_implicit_struct(Visitor *v,
80 void **obj,
81 size_t size,
82 Error **errp)
83 {
84 QapiDeallocVisitor *qov = to_qov(v);
85 qapi_dealloc_push(qov, obj);
86 }
87
88 static void qapi_dealloc_end_implicit_struct(Visitor *v, Error **errp)
89 {
90 QapiDeallocVisitor *qov = to_qov(v);
91 void **obj = qapi_dealloc_pop(qov);
92 if (obj) {
93 g_free(*obj);
94 }
95 }
96
97 static void qapi_dealloc_start_list(Visitor *v, const char *name, Error **errp)
98 {
99 QapiDeallocVisitor *qov = to_qov(v);
100 qapi_dealloc_push(qov, NULL);
101 }
102
103 static GenericList *qapi_dealloc_next_list(Visitor *v, GenericList **listp,
104 Error **errp)
105 {
106 GenericList *list = *listp;
107 QapiDeallocVisitor *qov = to_qov(v);
108 StackEntry *e = QTAILQ_FIRST(&qov->stack);
109
110 if (e && e->is_list_head) {
111 e->is_list_head = false;
112 return list;
113 }
114
115 if (list) {
116 list = list->next;
117 g_free(*listp);
118 return list;
119 }
120
121 return NULL;
122 }
123
124 static void qapi_dealloc_end_list(Visitor *v, Error **errp)
125 {
126 QapiDeallocVisitor *qov = to_qov(v);
127 void *obj = qapi_dealloc_pop(qov);
128 assert(obj == NULL); /* should've been list head tracker with no payload */
129 }
130
131 static void qapi_dealloc_type_str(Visitor *v, char **obj, const char *name,
132 Error **errp)
133 {
134 if (obj) {
135 g_free(*obj);
136 }
137 }
138
139 static void qapi_dealloc_type_int(Visitor *v, int64_t *obj, const char *name,
140 Error **errp)
141 {
142 }
143
144 static void qapi_dealloc_type_bool(Visitor *v, bool *obj, const char *name,
145 Error **errp)
146 {
147 }
148
149 static void qapi_dealloc_type_number(Visitor *v, double *obj, const char *name,
150 Error **errp)
151 {
152 }
153
154 static void qapi_dealloc_type_size(Visitor *v, uint64_t *obj, const char *name,
155 Error **errp)
156 {
157 }
158
159 static void qapi_dealloc_type_enum(Visitor *v, int *obj, const char *strings[],
160 const char *kind, const char *name,
161 Error **errp)
162 {
163 }
164
165 /* If there's no data present, the dealloc visitor has nothing to free.
166 * Thus, indicate to visitor code that the subsequent union fields can
167 * be skipped. This is not an error condition, since the cleanup of the
168 * rest of an object can continue unhindered, so leave errp unset in
169 * these cases.
170 *
171 * NOTE: In cases where we're attempting to deallocate an object that
172 * may have missing fields, the field indicating the union type may
173 * be missing. In such a case, it's possible we don't have enough
174 * information to differentiate data_present == false from a case where
175 * data *is* present but happens to be a scalar with a value of 0.
176 * This is okay, since in the case of the dealloc visitor there's no
177 * work that needs to done in either situation.
178 *
179 * The current inability in QAPI code to more thoroughly verify a union
180 * type in such cases will likely need to be addressed if we wish to
181 * implement this interface for other types of visitors in the future,
182 * however.
183 */
184 static bool qapi_dealloc_start_union(Visitor *v, bool data_present,
185 Error **errp)
186 {
187 return data_present;
188 }
189
190 Visitor *qapi_dealloc_get_visitor(QapiDeallocVisitor *v)
191 {
192 return &v->visitor;
193 }
194
195 void qapi_dealloc_visitor_cleanup(QapiDeallocVisitor *v)
196 {
197 g_free(v);
198 }
199
200 QapiDeallocVisitor *qapi_dealloc_visitor_new(void)
201 {
202 QapiDeallocVisitor *v;
203
204 v = g_malloc0(sizeof(*v));
205
206 v->visitor.start_struct = qapi_dealloc_start_struct;
207 v->visitor.end_struct = qapi_dealloc_end_struct;
208 v->visitor.start_implicit_struct = qapi_dealloc_start_implicit_struct;
209 v->visitor.end_implicit_struct = qapi_dealloc_end_implicit_struct;
210 v->visitor.start_list = qapi_dealloc_start_list;
211 v->visitor.next_list = qapi_dealloc_next_list;
212 v->visitor.end_list = qapi_dealloc_end_list;
213 v->visitor.type_enum = qapi_dealloc_type_enum;
214 v->visitor.type_int = qapi_dealloc_type_int;
215 v->visitor.type_bool = qapi_dealloc_type_bool;
216 v->visitor.type_str = qapi_dealloc_type_str;
217 v->visitor.type_number = qapi_dealloc_type_number;
218 v->visitor.type_size = qapi_dealloc_type_size;
219 v->visitor.start_union = qapi_dealloc_start_union;
220
221 QTAILQ_INIT(&v->stack);
222
223 return v;
224 }