qapi/qobject-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/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     qobject_incref(*obj);
 192     qobject_output_add_obj(qov, name, *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_decref() 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     qobject_incref(qov->root);
 214     *qov->result = qov->root;
 215     qov->result = NULL;
 216 }
 217
 218 static void qobject_output_free(Visitor *v)
 219 {
 220     QObjectOutputVisitor *qov = to_qov(v);
 221     QStackEntry *e;
 222
 223     while (!QSLIST_EMPTY(&qov->stack)) {
 224         e = QSLIST_FIRST(&qov->stack);
 225         QSLIST_REMOVE_HEAD(&qov->stack, node);
 226         g_free(e);
 227     }
 228
 229     qobject_decref(qov->root);
 230     g_free(qov);
 231 }
 232
 233 Visitor *qobject_output_visitor_new(QObject **result)
 234 {
 235     QObjectOutputVisitor *v;
 236
 237     v = g_malloc0(sizeof(*v));
 238
 239     v->visitor.type = VISITOR_OUTPUT;
 240     v->visitor.start_struct = qobject_output_start_struct;
 241     v->visitor.end_struct = qobject_output_end_struct;
 242     v->visitor.start_list = qobject_output_start_list;
 243     v->visitor.next_list = qobject_output_next_list;
 244     v->visitor.end_list = qobject_output_end_list;
 245     v->visitor.type_int64 = qobject_output_type_int64;
 246     v->visitor.type_uint64 = qobject_output_type_uint64;
 247     v->visitor.type_bool = qobject_output_type_bool;
 248     v->visitor.type_str = qobject_output_type_str;
 249     v->visitor.type_number = qobject_output_type_number;
 250     v->visitor.type_any = qobject_output_type_any;
 251     v->visitor.type_null = qobject_output_type_null;
 252     v->visitor.complete = qobject_output_complete;
 253     v->visitor.free = qobject_output_free;
 254
 255     *result = NULL;
 256     v->result = result;
 257
 258     return &v->visitor;
 259 }