1 /*
2  * Core Definitions for QAPI/QMP Command Registry
3  *
4  * Copyright (C) 2012-2016 Red Hat, Inc.
5  * Copyright IBM, Corp. 2011
6  *
7  * Authors:
8  *  Anthony Liguori   <aliguori@us.ibm.com>
9  *
10  * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
11  * See the COPYING.LIB file in the top-level directory.
12  *
13  */
14 
15 #include "qemu/osdep.h"
16 #include "qapi/qobject-output-visitor.h"
17 #include "qapi/visitor-impl.h"
18 #include "qemu/queue.h"
19 #include "qapi/qmp/qbool.h"
20 #include "qapi/qmp/qdict.h"
21 #include "qapi/qmp/qlist.h"
22 #include "qapi/qmp/qnull.h"
23 #include "qapi/qmp/qnum.h"
24 #include "qapi/qmp/qstring.h"
25 
26 typedef struct QStackEntry {
27     QObject *value;
28     void *qapi; /* sanity check that caller uses same pointer */
29     QSLIST_ENTRY(QStackEntry) node;
30 } QStackEntry;
31 
32 struct QObjectOutputVisitor {
33     Visitor visitor;
34     QSLIST_HEAD(, QStackEntry) stack; /* Stack of unfinished containers */
35     QObject *root; /* Root of the output visit */
36     QObject **result; /* User's storage location for result */
37 };
38 
39 #define qobject_output_add(qov, name, value) \
40     qobject_output_add_obj(qov, name, QOBJECT(value))
41 #define qobject_output_push(qov, value, qapi) \
42     qobject_output_push_obj(qov, QOBJECT(value), qapi)
43 
44 static QObjectOutputVisitor *to_qov(Visitor *v)
45 {
46     return container_of(v, QObjectOutputVisitor, visitor);
47 }
48 
49 /* Push @value onto the stack of current QObjects being built */
50 static void qobject_output_push_obj(QObjectOutputVisitor *qov, QObject *value,
51                                     void *qapi)
52 {
53     QStackEntry *e = g_malloc0(sizeof(*e));
54 
55     assert(qov->root);
56     assert(value);
57     e->value = value;
58     e->qapi = qapi;
59     QSLIST_INSERT_HEAD(&qov->stack, e, node);
60 }
61 
62 /* Pop a value off the stack of QObjects being built, and return it. */
63 static QObject *qobject_output_pop(QObjectOutputVisitor *qov, void *qapi)
64 {
65     QStackEntry *e = QSLIST_FIRST(&qov->stack);
66     QObject *value;
67 
68     assert(e);
69     assert(e->qapi == qapi);
70     QSLIST_REMOVE_HEAD(&qov->stack, node);
71     value = e->value;
72     assert(value);
73     g_free(e);
74     return value;
75 }
76 
77 /* Add @value to the current QObject being built.
78  * If the stack is visiting a dictionary or list, @value is now owned
79  * by that container. Otherwise, @value is now the root.  */
80 static void qobject_output_add_obj(QObjectOutputVisitor *qov, const char *name,
81                                    QObject *value)
82 {
83     QStackEntry *e = QSLIST_FIRST(&qov->stack);
84     QObject *cur = e ? e->value : NULL;
85 
86     if (!cur) {
87         /* Don't allow reuse of visitor on more than one root */
88         assert(!qov->root);
89         qov->root = value;
90     } else {
91         switch (qobject_type(cur)) {
92         case QTYPE_QDICT:
93             assert(name);
94             qdict_put_obj(qobject_to(QDict, cur), name, value);
95             break;
96         case QTYPE_QLIST:
97             assert(!name);
98             qlist_append_obj(qobject_to(QList, cur), value);
99             break;
100         default:
101             g_assert_not_reached();
102         }
103     }
104 }
105 
106 static bool qobject_output_start_struct(Visitor *v, const char *name,
107                                         void **obj, size_t unused, Error **errp)
108 {
109     QObjectOutputVisitor *qov = to_qov(v);
110     QDict *dict = qdict_new();
111 
112     qobject_output_add(qov, name, dict);
113     qobject_output_push(qov, dict, obj);
114     return true;
115 }
116 
117 static void qobject_output_end_struct(Visitor *v, void **obj)
118 {
119     QObjectOutputVisitor *qov = to_qov(v);
120     QObject *value = qobject_output_pop(qov, obj);
121     assert(qobject_type(value) == QTYPE_QDICT);
122 }
123 
124 static bool qobject_output_start_list(Visitor *v, const char *name,
125                                       GenericList **listp, size_t size,
126                                       Error **errp)
127 {
128     QObjectOutputVisitor *qov = to_qov(v);
129     QList *list = qlist_new();
130 
131     qobject_output_add(qov, name, list);
132     qobject_output_push(qov, list, listp);
133     return true;
134 }
135 
136 static GenericList *qobject_output_next_list(Visitor *v, GenericList *tail,
137                                              size_t size)
138 {
139     return tail->next;
140 }
141 
142 static void qobject_output_end_list(Visitor *v, void **obj)
143 {
144     QObjectOutputVisitor *qov = to_qov(v);
145     QObject *value = qobject_output_pop(qov, obj);
146     assert(qobject_type(value) == QTYPE_QLIST);
147 }
148 
149 static bool qobject_output_type_int64(Visitor *v, const char *name,
150                                       int64_t *obj, Error **errp)
151 {
152     QObjectOutputVisitor *qov = to_qov(v);
153     qobject_output_add(qov, name, qnum_from_int(*obj));
154     return true;
155 }
156 
157 static bool qobject_output_type_uint64(Visitor *v, const char *name,
158                                        uint64_t *obj, Error **errp)
159 {
160     QObjectOutputVisitor *qov = to_qov(v);
161     qobject_output_add(qov, name, qnum_from_uint(*obj));
162     return true;
163 }
164 
165 static bool qobject_output_type_bool(Visitor *v, const char *name, bool *obj,
166                                      Error **errp)
167 {
168     QObjectOutputVisitor *qov = to_qov(v);
169     qobject_output_add(qov, name, qbool_from_bool(*obj));
170     return true;
171 }
172 
173 static bool qobject_output_type_str(Visitor *v, const char *name, char **obj,
174                                     Error **errp)
175 {
176     QObjectOutputVisitor *qov = to_qov(v);
177     if (*obj) {
178         qobject_output_add(qov, name, qstring_from_str(*obj));
179     } else {
180         qobject_output_add(qov, name, qstring_from_str(""));
181     }
182     return true;
183 }
184 
185 static bool qobject_output_type_number(Visitor *v, const char *name,
186                                        double *obj, Error **errp)
187 {
188     QObjectOutputVisitor *qov = to_qov(v);
189     qobject_output_add(qov, name, qnum_from_double(*obj));
190     return true;
191 }
192 
193 static bool qobject_output_type_any(Visitor *v, const char *name,
194                                     QObject **obj, Error **errp)
195 {
196     QObjectOutputVisitor *qov = to_qov(v);
197 
198     qobject_output_add_obj(qov, name, qobject_ref(*obj));
199     return true;
200 }
201 
202 static bool qobject_output_type_null(Visitor *v, const char *name,
203                                      QNull **obj, Error **errp)
204 {
205     QObjectOutputVisitor *qov = to_qov(v);
206     qobject_output_add(qov, name, qnull());
207     return true;
208 }
209 
210 /* Finish building, and return the root object.
211  * The root object is never null. The caller becomes the object's
212  * owner, and should use qobject_unref() when done with it.  */
213 static void qobject_output_complete(Visitor *v, void *opaque)
214 {
215     QObjectOutputVisitor *qov = to_qov(v);
216 
217     /* A visit must have occurred, with each start paired with end.  */
218     assert(qov->root && QSLIST_EMPTY(&qov->stack));
219     assert(opaque == qov->result);
220 
221     *qov->result = qobject_ref(qov->root);
222     qov->result = NULL;
223 }
224 
225 static void qobject_output_free(Visitor *v)
226 {
227     QObjectOutputVisitor *qov = to_qov(v);
228     QStackEntry *e;
229 
230     while (!QSLIST_EMPTY(&qov->stack)) {
231         e = QSLIST_FIRST(&qov->stack);
232         QSLIST_REMOVE_HEAD(&qov->stack, node);
233         g_free(e);
234     }
235 
236     qobject_unref(qov->root);
237     g_free(qov);
238 }
239 
240 Visitor *qobject_output_visitor_new(QObject **result)
241 {
242     QObjectOutputVisitor *v;
243 
244     v = g_malloc0(sizeof(*v));
245 
246     v->visitor.type = VISITOR_OUTPUT;
247     v->visitor.start_struct = qobject_output_start_struct;
248     v->visitor.end_struct = qobject_output_end_struct;
249     v->visitor.start_list = qobject_output_start_list;
250     v->visitor.next_list = qobject_output_next_list;
251     v->visitor.end_list = qobject_output_end_list;
252     v->visitor.type_int64 = qobject_output_type_int64;
253     v->visitor.type_uint64 = qobject_output_type_uint64;
254     v->visitor.type_bool = qobject_output_type_bool;
255     v->visitor.type_str = qobject_output_type_str;
256     v->visitor.type_number = qobject_output_type_number;
257     v->visitor.type_any = qobject_output_type_any;
258     v->visitor.type_null = qobject_output_type_null;
259     v->visitor.complete = qobject_output_complete;
260     v->visitor.free = qobject_output_free;
261 
262     *result = NULL;
263     v->result = result;
264 
265     return &v->visitor;
266 }
267