qapi/qmp-output-visitor.c

   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/qmp-output-visitor.h"
  17 #include "qapi/visitor-impl.h"
  18 #include "qemu/queue.h"
  19 #include "qemu-common.h"
  20 #include "qapi/qmp/types.h"
  21
  22 typedef struct QStackEntry
  23 {
  24     QObject *value;
  25     void *qapi; /* sanity check that caller uses same pointer */
  26     QTAILQ_ENTRY(QStackEntry) node;
  27 } QStackEntry;
  28
  29 typedef QTAILQ_HEAD(QStack, QStackEntry) QStack;
  30
  31 struct QmpOutputVisitor
  32 {
  33     Visitor visitor;
  34     QStack stack; /* Stack of containers that haven't yet been finished */
  35     QObject *root; /* Root of the output visit */
  36 };
  37
  38 #define qmp_output_add(qov, name, value) \
  39     qmp_output_add_obj(qov, name, QOBJECT(value))
  40 #define qmp_output_push(qov, value, qapi) \
  41     qmp_output_push_obj(qov, QOBJECT(value), qapi)
  42
  43 static QmpOutputVisitor *to_qov(Visitor *v)
  44 {
  45     return container_of(v, QmpOutputVisitor, visitor);
  46 }
  47
  48 /* Push @value onto the stack of current QObjects being built */
  49 static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value,
  50                                 void *qapi)
  51 {
  52     QStackEntry *e = g_malloc0(sizeof(*e));
  53
  54     assert(qov->root);
  55     assert(value);
  56     e->value = value;
  57     e->qapi = qapi;
  58     QTAILQ_INSERT_HEAD(&qov->stack, e, node);
  59 }
  60
  61 /* Pop a value off the stack of QObjects being built, and return it. */
  62 static QObject *qmp_output_pop(QmpOutputVisitor *qov, void *qapi)
  63 {
  64     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
  65     QObject *value;
  66
  67     assert(e);
  68     assert(e->qapi == qapi);
  69     QTAILQ_REMOVE(&qov->stack, e, node);
  70     value = e->value;
  71     assert(value);
  72     g_free(e);
  73     return value;
  74 }
  75
  76 /* Add @value to the current QObject being built.
  77  * If the stack is visiting a dictionary or list, @value is now owned
  78  * by that container. Otherwise, @value is now the root.  */
  79 static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
  80                                QObject *value)
  81 {
  82     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
  83     QObject *cur = e ? e->value : NULL;
  84
  85     if (!cur) {
  86         /* Don't allow reuse of visitor on more than one root */
  87         assert(!qov->root);
  88         qov->root = value;
  89     } else {
  90         switch (qobject_type(cur)) {
  91         case QTYPE_QDICT:
  92             assert(name);
  93             qdict_put_obj(qobject_to_qdict(cur), name, value);
  94             break;
  95         case QTYPE_QLIST:
  96             assert(!name);
  97             qlist_append_obj(qobject_to_qlist(cur), value);
  98             break;
  99         default:
 100             g_assert_not_reached();
 101         }
 102     }
 103 }
 104
 105 static void qmp_output_start_struct(Visitor *v, const char *name, void **obj,
 106                                     size_t unused, Error **errp)
 107 {
 108     QmpOutputVisitor *qov = to_qov(v);
 109     QDict *dict = qdict_new();
 110
 111     qmp_output_add(qov, name, dict);
 112     qmp_output_push(qov, dict, obj);
 113 }
 114
 115 static void qmp_output_end_struct(Visitor *v, void **obj)
 116 {
 117     QmpOutputVisitor *qov = to_qov(v);
 118     QObject *value = qmp_output_pop(qov, obj);
 119     assert(qobject_type(value) == QTYPE_QDICT);
 120 }
 121
 122 static void qmp_output_start_list(Visitor *v, const char *name,
 123                                   GenericList **listp, size_t size,
 124                                   Error **errp)
 125 {
 126     QmpOutputVisitor *qov = to_qov(v);
 127     QList *list = qlist_new();
 128
 129     qmp_output_add(qov, name, list);
 130     qmp_output_push(qov, list, listp);
 131 }
 132
 133 static GenericList *qmp_output_next_list(Visitor *v, GenericList *tail,
 134                                          size_t size)
 135 {
 136     return tail->next;
 137 }
 138
 139 static void qmp_output_end_list(Visitor *v, void **obj)
 140 {
 141     QmpOutputVisitor *qov = to_qov(v);
 142     QObject *value = qmp_output_pop(qov, obj);
 143     assert(qobject_type(value) == QTYPE_QLIST);
 144 }
 145
 146 static void qmp_output_type_int64(Visitor *v, const char *name, int64_t *obj,
 147                                   Error **errp)
 148 {
 149     QmpOutputVisitor *qov = to_qov(v);
 150     qmp_output_add(qov, name, qint_from_int(*obj));
 151 }
 152
 153 static void qmp_output_type_uint64(Visitor *v, const char *name, uint64_t *obj,
 154                                    Error **errp)
 155 {
 156     /* FIXME: QMP outputs values larger than INT64_MAX as negative */
 157     QmpOutputVisitor *qov = to_qov(v);
 158     qmp_output_add(qov, name, qint_from_int(*obj));
 159 }
 160
 161 static void qmp_output_type_bool(Visitor *v, const char *name, bool *obj,
 162                                  Error **errp)
 163 {
 164     QmpOutputVisitor *qov = to_qov(v);
 165     qmp_output_add(qov, name, qbool_from_bool(*obj));
 166 }
 167
 168 static void qmp_output_type_str(Visitor *v, const char *name, char **obj,
 169                                 Error **errp)
 170 {
 171     QmpOutputVisitor *qov = to_qov(v);
 172     if (*obj) {
 173         qmp_output_add(qov, name, qstring_from_str(*obj));
 174     } else {
 175         qmp_output_add(qov, name, qstring_from_str(""));
 176     }
 177 }
 178
 179 static void qmp_output_type_number(Visitor *v, const char *name, double *obj,
 180                                    Error **errp)
 181 {
 182     QmpOutputVisitor *qov = to_qov(v);
 183     qmp_output_add(qov, name, qfloat_from_double(*obj));
 184 }
 185
 186 static void qmp_output_type_any(Visitor *v, const char *name, QObject **obj,
 187                                 Error **errp)
 188 {
 189     QmpOutputVisitor *qov = to_qov(v);
 190     qobject_incref(*obj);
 191     qmp_output_add_obj(qov, name, *obj);
 192 }
 193
 194 static void qmp_output_type_null(Visitor *v, const char *name, Error **errp)
 195 {
 196     QmpOutputVisitor *qov = to_qov(v);
 197     qmp_output_add_obj(qov, name, qnull());
 198 }
 199
 200 /* Finish building, and return the root object.
 201  * The root object is never null. The caller becomes the object's
 202  * owner, and should use qobject_decref() when done with it.  */
 203 QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
 204 {
 205     /* A visit must have occurred, with each start paired with end.  */
 206     assert(qov->root && QTAILQ_EMPTY(&qov->stack));
 207
 208     qobject_incref(qov->root);
 209     return qov->root;
 210 }
 211
 212 Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
 213 {
 214     return &v->visitor;
 215 }
 216
 217 static void qmp_output_free(Visitor *v)
 218 {
 219     QmpOutputVisitor *qov = to_qov(v);
 220     QStackEntry *e, *tmp;
 221
 222     QTAILQ_FOREACH_SAFE(e, &qov->stack, node, tmp) {
 223         QTAILQ_REMOVE(&qov->stack, e, node);
 224         g_free(e);
 225     }
 226
 227     qobject_decref(qov->root);
 228     g_free(qov);
 229 }
 230
 231 QmpOutputVisitor *qmp_output_visitor_new(void)
 232 {
 233     QmpOutputVisitor *v;
 234
 235     v = g_malloc0(sizeof(*v));
 236
 237     v->visitor.type = VISITOR_OUTPUT;
 238     v->visitor.start_struct = qmp_output_start_struct;
 239     v->visitor.end_struct = qmp_output_end_struct;
 240     v->visitor.start_list = qmp_output_start_list;
 241     v->visitor.next_list = qmp_output_next_list;
 242     v->visitor.end_list = qmp_output_end_list;
 243     v->visitor.type_int64 = qmp_output_type_int64;
 244     v->visitor.type_uint64 = qmp_output_type_uint64;
 245     v->visitor.type_bool = qmp_output_type_bool;
 246     v->visitor.type_str = qmp_output_type_str;
 247     v->visitor.type_number = qmp_output_type_number;
 248     v->visitor.type_any = qmp_output_type_any;
 249     v->visitor.type_null = qmp_output_type_null;
 250     v->visitor.free = qmp_output_free;
 251
 252     QTAILQ_INIT(&v->stack);
 253
 254     return v;
 255 }