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