qapi/qmp-output-visitor.c

   1 /*
   2  * Core Definitions for QAPI/QMP Command Registry
   3  *
   4  * Copyright IBM, Corp. 2011
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.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 "qemu/osdep.h"
  15 #include "qapi/qmp-output-visitor.h"
  16 #include "qapi/visitor-impl.h"
  17 #include "qemu/queue.h"
  18 #include "qemu-common.h"
  19 #include "qapi/qmp/types.h"
  20
  21 typedef struct QStackEntry
  22 {
  23     QObject *value;
  24     bool is_list_head;
  25     QTAILQ_ENTRY(QStackEntry) node;
  26 } QStackEntry;
  27
  28 typedef QTAILQ_HEAD(QStack, QStackEntry) QStack;
  29
  30 struct QmpOutputVisitor
  31 {
  32     Visitor visitor;
  33     QStack stack;
  34 };
  35
  36 #define qmp_output_add(qov, name, value) \
  37     qmp_output_add_obj(qov, name, QOBJECT(value))
  38 #define qmp_output_push(qov, value) qmp_output_push_obj(qov, QOBJECT(value))
  39
  40 static QmpOutputVisitor *to_qov(Visitor *v)
  41 {
  42     return container_of(v, QmpOutputVisitor, visitor);
  43 }
  44
  45 static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value)
  46 {
  47     QStackEntry *e = g_malloc0(sizeof(*e));
  48
  49     e->value = value;
  50     if (qobject_type(e->value) == QTYPE_QLIST) {
  51         e->is_list_head = true;
  52     }
  53     QTAILQ_INSERT_HEAD(&qov->stack, e, node);
  54 }
  55
  56 static QObject *qmp_output_pop(QmpOutputVisitor *qov)
  57 {
  58     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
  59     QObject *value;
  60     QTAILQ_REMOVE(&qov->stack, e, node);
  61     value = e->value;
  62     g_free(e);
  63     return value;
  64 }
  65
  66 static QObject *qmp_output_first(QmpOutputVisitor *qov)
  67 {
  68     QStackEntry *e = QTAILQ_LAST(&qov->stack, QStack);
  69
  70     /*
  71      * FIXME Wrong, because qmp_output_get_qobject() will increment
  72      * the refcnt *again*.  We need to think through how visitors
  73      * handle null.
  74      */
  75     if (!e) {
  76         return qnull();
  77     }
  78
  79     return e->value;
  80 }
  81
  82 static QObject *qmp_output_last(QmpOutputVisitor *qov)
  83 {
  84     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
  85     return e->value;
  86 }
  87
  88 static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
  89                                QObject *value)
  90 {
  91     QObject *cur;
  92
  93     if (QTAILQ_EMPTY(&qov->stack)) {
  94         qmp_output_push_obj(qov, value);
  95         return;
  96     }
  97
  98     cur = qmp_output_last(qov);
  99
 100     switch (qobject_type(cur)) {
 101     case QTYPE_QDICT:
 102         qdict_put_obj(qobject_to_qdict(cur), name, value);
 103         break;
 104     case QTYPE_QLIST:
 105         qlist_append_obj(qobject_to_qlist(cur), value);
 106         break;
 107     default:
 108         qobject_decref(qmp_output_pop(qov));
 109         qmp_output_push_obj(qov, value);
 110         break;
 111     }
 112 }
 113
 114 static void qmp_output_start_struct(Visitor *v, void **obj, const char *kind,
 115                                     const char *name, size_t unused,
 116                                     Error **errp)
 117 {
 118     QmpOutputVisitor *qov = to_qov(v);
 119     QDict *dict = qdict_new();
 120
 121     qmp_output_add(qov, name, dict);
 122     qmp_output_push(qov, dict);
 123 }
 124
 125 static void qmp_output_end_struct(Visitor *v, Error **errp)
 126 {
 127     QmpOutputVisitor *qov = to_qov(v);
 128     qmp_output_pop(qov);
 129 }
 130
 131 static void qmp_output_start_list(Visitor *v, const char *name, Error **errp)
 132 {
 133     QmpOutputVisitor *qov = to_qov(v);
 134     QList *list = qlist_new();
 135
 136     qmp_output_add(qov, name, list);
 137     qmp_output_push(qov, list);
 138 }
 139
 140 static GenericList *qmp_output_next_list(Visitor *v, GenericList **listp,
 141                                          Error **errp)
 142 {
 143     GenericList *list = *listp;
 144     QmpOutputVisitor *qov = to_qov(v);
 145     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
 146
 147     assert(e);
 148     if (e->is_list_head) {
 149         e->is_list_head = false;
 150         return list;
 151     }
 152
 153     return list ? list->next : NULL;
 154 }
 155
 156 static void qmp_output_end_list(Visitor *v, Error **errp)
 157 {
 158     QmpOutputVisitor *qov = to_qov(v);
 159     qmp_output_pop(qov);
 160 }
 161
 162 static void qmp_output_type_int64(Visitor *v, int64_t *obj, const char *name,
 163                                   Error **errp)
 164 {
 165     QmpOutputVisitor *qov = to_qov(v);
 166     qmp_output_add(qov, name, qint_from_int(*obj));
 167 }
 168
 169 static void qmp_output_type_uint64(Visitor *v, uint64_t *obj, const char *name,
 170                                    Error **errp)
 171 {
 172     /* FIXME: QMP outputs values larger than INT64_MAX as negative */
 173     QmpOutputVisitor *qov = to_qov(v);
 174     qmp_output_add(qov, name, qint_from_int(*obj));
 175 }
 176
 177 static void qmp_output_type_bool(Visitor *v, bool *obj, const char *name,
 178                                  Error **errp)
 179 {
 180     QmpOutputVisitor *qov = to_qov(v);
 181     qmp_output_add(qov, name, qbool_from_bool(*obj));
 182 }
 183
 184 static void qmp_output_type_str(Visitor *v, char **obj, const char *name,
 185                                 Error **errp)
 186 {
 187     QmpOutputVisitor *qov = to_qov(v);
 188     if (*obj) {
 189         qmp_output_add(qov, name, qstring_from_str(*obj));
 190     } else {
 191         qmp_output_add(qov, name, qstring_from_str(""));
 192     }
 193 }
 194
 195 static void qmp_output_type_number(Visitor *v, double *obj, const char *name,
 196                                    Error **errp)
 197 {
 198     QmpOutputVisitor *qov = to_qov(v);
 199     qmp_output_add(qov, name, qfloat_from_double(*obj));
 200 }
 201
 202 static void qmp_output_type_any(Visitor *v, QObject **obj, const char *name,
 203                                 Error **errp)
 204 {
 205     QmpOutputVisitor *qov = to_qov(v);
 206     qobject_incref(*obj);
 207     qmp_output_add_obj(qov, name, *obj);
 208 }
 209
 210 QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
 211 {
 212     QObject *obj = qmp_output_first(qov);
 213     if (obj) {
 214         qobject_incref(obj);
 215     }
 216     return obj;
 217 }
 218
 219 Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
 220 {
 221     return &v->visitor;
 222 }
 223
 224 void qmp_output_visitor_cleanup(QmpOutputVisitor *v)
 225 {
 226     QStackEntry *e, *tmp;
 227
 228     /* The bottom QStackEntry, if any, owns the root QObject. See the
 229      * qmp_output_push_obj() invocations in qmp_output_add_obj(). */
 230     QObject *root = QTAILQ_EMPTY(&v->stack) ? NULL : qmp_output_first(v);
 231
 232     QTAILQ_FOREACH_SAFE(e, &v->stack, node, tmp) {
 233         QTAILQ_REMOVE(&v->stack, e, node);
 234         g_free(e);
 235     }
 236
 237     qobject_decref(root);
 238     g_free(v);
 239 }
 240
 241 QmpOutputVisitor *qmp_output_visitor_new(void)
 242 {
 243     QmpOutputVisitor *v;
 244
 245     v = g_malloc0(sizeof(*v));
 246
 247     v->visitor.start_struct = qmp_output_start_struct;
 248     v->visitor.end_struct = qmp_output_end_struct;
 249     v->visitor.start_list = qmp_output_start_list;
 250     v->visitor.next_list = qmp_output_next_list;
 251     v->visitor.end_list = qmp_output_end_list;
 252     v->visitor.type_enum = output_type_enum;
 253     v->visitor.type_int64 = qmp_output_type_int64;
 254     v->visitor.type_uint64 = qmp_output_type_uint64;
 255     v->visitor.type_bool = qmp_output_type_bool;
 256     v->visitor.type_str = qmp_output_type_str;
 257     v->visitor.type_number = qmp_output_type_number;
 258     v->visitor.type_any = qmp_output_type_any;
 259
 260     QTAILQ_INIT(&v->stack);
 261
 262     return v;
 263 }