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   <[email protected]>
   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 "qapi/qmp/qbool.h"
  20 #include "qapi/qmp/qdict.h"
  21 #include "qapi/qmp/qlist.h"
  22 #include "qapi/qmp/qnull.h"
  23 #include "qapi/qmp/qnum.h"
  24 #include "qapi/qmp/qstring.h"
  25
  26 typedef struct QStackEntry {
  27     QObject *value;
  28     void *qapi; /* sanity check that caller uses same pointer */
  29     QSLIST_ENTRY(QStackEntry) node;
  30 } QStackEntry;
  31
  32 struct QObjectOutputVisitor {
  33     Visitor visitor;
  34
  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 bool 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     return true;
 116 }
 117
 118 static void qobject_output_end_struct(Visitor *v, void **obj)
 119 {
 120     QObjectOutputVisitor *qov = to_qov(v);
 121     QObject *value = qobject_output_pop(qov, obj);
 122     assert(qobject_type(value) == QTYPE_QDICT);
 123 }
 124
 125 static bool qobject_output_start_list(Visitor *v, const char *name,
 126                                       GenericList **listp, size_t size,
 127                                       Error **errp)
 128 {
 129     QObjectOutputVisitor *qov = to_qov(v);
 130     QList *list = qlist_new();
 131
 132     qobject_output_add(qov, name, list);
 133     qobject_output_push(qov, list, listp);
 134     return true;
 135 }
 136
 137 static GenericList *qobject_output_next_list(Visitor *v, GenericList *tail,
 138                                              size_t size)
 139 {
 140     return tail->next;
 141 }
 142
 143 static void qobject_output_end_list(Visitor *v, void **obj)
 144 {
 145     QObjectOutputVisitor *qov = to_qov(v);
 146     QObject *value = qobject_output_pop(qov, obj);
 147     assert(qobject_type(value) == QTYPE_QLIST);
 148 }
 149
 150 static bool qobject_output_type_int64(Visitor *v, const char *name,
 151                                       int64_t *obj, Error **errp)
 152 {
 153     QObjectOutputVisitor *qov = to_qov(v);
 154     qobject_output_add(qov, name, qnum_from_int(*obj));
 155     return true;
 156 }
 157
 158 static bool qobject_output_type_uint64(Visitor *v, const char *name,
 159                                        uint64_t *obj, Error **errp)
 160 {
 161     QObjectOutputVisitor *qov = to_qov(v);
 162     qobject_output_add(qov, name, qnum_from_uint(*obj));
 163     return true;
 164 }
 165
 166 static bool qobject_output_type_bool(Visitor *v, const char *name, bool *obj,
 167                                      Error **errp)
 168 {
 169     QObjectOutputVisitor *qov = to_qov(v);
 170     qobject_output_add(qov, name, qbool_from_bool(*obj));
 171     return true;
 172 }
 173
 174 static bool qobject_output_type_str(Visitor *v, const char *name, char **obj,
 175                                     Error **errp)
 176 {
 177     QObjectOutputVisitor *qov = to_qov(v);
 178     if (*obj) {
 179         qobject_output_add(qov, name, qstring_from_str(*obj));
 180     } else {
 181         qobject_output_add(qov, name, qstring_from_str(""));
 182     }
 183     return true;
 184 }
 185
 186 static bool qobject_output_type_number(Visitor *v, const char *name,
 187                                        double *obj, Error **errp)
 188 {
 189     QObjectOutputVisitor *qov = to_qov(v);
 190     qobject_output_add(qov, name, qnum_from_double(*obj));
 191     return true;
 192 }
 193
 194 static bool qobject_output_type_any(Visitor *v, const char *name,
 195                                     QObject **obj, Error **errp)
 196 {
 197     QObjectOutputVisitor *qov = to_qov(v);
 198
 199     qobject_output_add_obj(qov, name, qobject_ref(*obj));
 200     return true;
 201 }
 202
 203 static bool qobject_output_type_null(Visitor *v, const char *name,
 204                                      QNull **obj, Error **errp)
 205 {
 206     QObjectOutputVisitor *qov = to_qov(v);
 207     qobject_output_add(qov, name, qnull());
 208     return true;
 209 }
 210
 211 static bool qobject_output_deprecated(Visitor *v, const char *name)
 212 {
 213     return v->compat_policy.deprecated_output != COMPAT_POLICY_OUTPUT_HIDE;
 214 }
 215
 216 /* Finish building, and return the root object.
 217  * The root object is never null. The caller becomes the object's
 218  * owner, and should use qobject_unref() when done with it.  */
 219 static void qobject_output_complete(Visitor *v, void *opaque)
 220 {
 221     QObjectOutputVisitor *qov = to_qov(v);
 222
 223     /* A visit must have occurred, with each start paired with end.  */
 224     assert(qov->root && QSLIST_EMPTY(&qov->stack));
 225     assert(opaque == qov->result);
 226
 227     *qov->result = qobject_ref(qov->root);
 228     qov->result = NULL;
 229 }
 230
 231 static void qobject_output_free(Visitor *v)
 232 {
 233     QObjectOutputVisitor *qov = to_qov(v);
 234     QStackEntry *e;
 235
 236     while (!QSLIST_EMPTY(&qov->stack)) {
 237         e = QSLIST_FIRST(&qov->stack);
 238         QSLIST_REMOVE_HEAD(&qov->stack, node);
 239         g_free(e);
 240     }
 241
 242     qobject_unref(qov->root);
 243     g_free(qov);
 244 }
 245
 246 Visitor *qobject_output_visitor_new(QObject **result)
 247 {
 248     QObjectOutputVisitor *v;
 249
 250     v = g_malloc0(sizeof(*v));
 251
 252     v->visitor.type = VISITOR_OUTPUT;
 253     v->visitor.start_struct = qobject_output_start_struct;
 254     v->visitor.end_struct = qobject_output_end_struct;
 255     v->visitor.start_list = qobject_output_start_list;
 256     v->visitor.next_list = qobject_output_next_list;
 257     v->visitor.end_list = qobject_output_end_list;
 258     v->visitor.type_int64 = qobject_output_type_int64;
 259     v->visitor.type_uint64 = qobject_output_type_uint64;
 260     v->visitor.type_bool = qobject_output_type_bool;
 261     v->visitor.type_str = qobject_output_type_str;
 262     v->visitor.type_number = qobject_output_type_number;
 263     v->visitor.type_any = qobject_output_type_any;
 264     v->visitor.type_null = qobject_output_type_null;
 265     v->visitor.deprecated = qobject_output_deprecated;
 266     v->visitor.complete = qobject_output_complete;
 267     v->visitor.free = qobject_output_free;
 268
 269     *result = NULL;
 270     v->result = result;
 271
 272     return &v->visitor;
 273 }