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     bool is_list_head;
  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) qmp_output_push_obj(qov, QOBJECT(value))
  41
  42 static QmpOutputVisitor *to_qov(Visitor *v)
  43 {
  44     return container_of(v, QmpOutputVisitor, visitor);
  45 }
  46
  47 /* Push @value onto the stack of current QObjects being built */
  48 static void qmp_output_push_obj(QmpOutputVisitor *qov, QObject *value)
  49 {
  50     QStackEntry *e = g_malloc0(sizeof(*e));
  51
  52     assert(qov->root);
  53     assert(value);
  54     e->value = value;
  55     if (qobject_type(e->value) == QTYPE_QLIST) {
  56         e->is_list_head = true;
  57     }
  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)
  63 {
  64     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
  65     QObject *value;
  66
  67     assert(e);
  68     QTAILQ_REMOVE(&qov->stack, e, node);
  69     value = e->value;
  70     assert(value);
  71     g_free(e);
  72     return value;
  73 }
  74
  75 /* Add @value to the current QObject being built.
  76  * If the stack is visiting a dictionary or list, @value is now owned
  77  * by that container. Otherwise, @value is now the root.  */
  78 static void qmp_output_add_obj(QmpOutputVisitor *qov, const char *name,
  79                                QObject *value)
  80 {
  81     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
  82     QObject *cur = e ? e->value : NULL;
  83
  84     if (!cur) {
  85         /* FIXME we should require the user to reset the visitor, rather
  86          * than throwing away the previous root */
  87         qobject_decref(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             qlist_append_obj(qobject_to_qlist(cur), value);
  97             break;
  98         default:
  99             g_assert_not_reached();
 100         }
 101     }
 102 }
 103
 104 static void qmp_output_start_struct(Visitor *v, const char *name, void **obj,
 105                                     size_t unused, Error **errp)
 106 {
 107     QmpOutputVisitor *qov = to_qov(v);
 108     QDict *dict = qdict_new();
 109
 110     qmp_output_add(qov, name, dict);
 111     qmp_output_push(qov, dict);
 112 }
 113
 114 static void qmp_output_end_struct(Visitor *v, Error **errp)
 115 {
 116     QmpOutputVisitor *qov = to_qov(v);
 117     qmp_output_pop(qov);
 118 }
 119
 120 static void qmp_output_start_list(Visitor *v, const char *name, Error **errp)
 121 {
 122     QmpOutputVisitor *qov = to_qov(v);
 123     QList *list = qlist_new();
 124
 125     qmp_output_add(qov, name, list);
 126     qmp_output_push(qov, list);
 127 }
 128
 129 static GenericList *qmp_output_next_list(Visitor *v, GenericList **listp,
 130                                          size_t size)
 131 {
 132     GenericList *list = *listp;
 133     QmpOutputVisitor *qov = to_qov(v);
 134     QStackEntry *e = QTAILQ_FIRST(&qov->stack);
 135
 136     assert(e);
 137     if (e->is_list_head) {
 138         e->is_list_head = false;
 139         return list;
 140     }
 141
 142     return list ? list->next : NULL;
 143 }
 144
 145 static void qmp_output_end_list(Visitor *v)
 146 {
 147     QmpOutputVisitor *qov = to_qov(v);
 148     qmp_output_pop(qov);
 149 }
 150
 151 static void qmp_output_type_int64(Visitor *v, const char *name, int64_t *obj,
 152                                   Error **errp)
 153 {
 154     QmpOutputVisitor *qov = to_qov(v);
 155     qmp_output_add(qov, name, qint_from_int(*obj));
 156 }
 157
 158 static void qmp_output_type_uint64(Visitor *v, const char *name, uint64_t *obj,
 159                                    Error **errp)
 160 {
 161     /* FIXME: QMP outputs values larger than INT64_MAX as negative */
 162     QmpOutputVisitor *qov = to_qov(v);
 163     qmp_output_add(qov, name, qint_from_int(*obj));
 164 }
 165
 166 static void qmp_output_type_bool(Visitor *v, const char *name, bool *obj,
 167                                  Error **errp)
 168 {
 169     QmpOutputVisitor *qov = to_qov(v);
 170     qmp_output_add(qov, name, qbool_from_bool(*obj));
 171 }
 172
 173 static void qmp_output_type_str(Visitor *v, const char *name, char **obj,
 174                                 Error **errp)
 175 {
 176     QmpOutputVisitor *qov = to_qov(v);
 177     if (*obj) {
 178         qmp_output_add(qov, name, qstring_from_str(*obj));
 179     } else {
 180         qmp_output_add(qov, name, qstring_from_str(""));
 181     }
 182 }
 183
 184 static void qmp_output_type_number(Visitor *v, const char *name, double *obj,
 185                                    Error **errp)
 186 {
 187     QmpOutputVisitor *qov = to_qov(v);
 188     qmp_output_add(qov, name, qfloat_from_double(*obj));
 189 }
 190
 191 static void qmp_output_type_any(Visitor *v, const char *name, QObject **obj,
 192                                 Error **errp)
 193 {
 194     QmpOutputVisitor *qov = to_qov(v);
 195     qobject_incref(*obj);
 196     qmp_output_add_obj(qov, name, *obj);
 197 }
 198
 199 /* Finish building, and return the root object. Will not be NULL. */
 200 QObject *qmp_output_get_qobject(QmpOutputVisitor *qov)
 201 {
 202     /* FIXME: we should require that a visit occurred, and that it is
 203      * complete (no starts without a matching end) */
 204     QObject *obj = qov->root;
 205     if (obj) {
 206         qobject_incref(obj);
 207     } else {
 208         obj = qnull();
 209     }
 210     return obj;
 211 }
 212
 213 Visitor *qmp_output_get_visitor(QmpOutputVisitor *v)
 214 {
 215     return &v->visitor;
 216 }
 217
 218 void qmp_output_visitor_cleanup(QmpOutputVisitor *v)
 219 {
 220     QStackEntry *e, *tmp;
 221
 222     QTAILQ_FOREACH_SAFE(e, &v->stack, node, tmp) {
 223         QTAILQ_REMOVE(&v->stack, e, node);
 224         g_free(e);
 225     }
 226
 227     qobject_decref(v->root);
 228     g_free(v);
 229 }
 230
 231 QmpOutputVisitor *qmp_output_visitor_new(void)
 232 {
 233     QmpOutputVisitor *v;
 234
 235     v = g_malloc0(sizeof(*v));
 236
 237     v->visitor.start_struct = qmp_output_start_struct;
 238     v->visitor.end_struct = qmp_output_end_struct;
 239     v->visitor.start_list = qmp_output_start_list;
 240     v->visitor.next_list = qmp_output_next_list;
 241     v->visitor.end_list = qmp_output_end_list;
 242     v->visitor.type_enum = output_type_enum;
 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
 250     QTAILQ_INIT(&v->stack);
 251
 252     return v;
 253 }