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/types.h"
  21
  22 typedef struct QStackEntry {
  23     QObject *value;
  24     void *qapi; /* sanity check that caller uses same pointer */
  25     QSLIST_ENTRY(QStackEntry) node;
  26 } QStackEntry;
  27
  28 struct QObjectOutputVisitor {
  29     Visitor visitor;
  30     QSLIST_HEAD(, QStackEntry) stack; /* Stack of unfinished containers */
  31     QObject *root; /* Root of the output visit */
  32     QObject **result; /* User's storage location for result */
  33 };
  34
  35 #define qobject_output_add(qov, name, value) \
  36     qobject_output_add_obj(qov, name, QOBJECT(value))
  37 #define qobject_output_push(qov, value, qapi) \
  38     qobject_output_push_obj(qov, QOBJECT(value), qapi)
  39
  40 static QObjectOutputVisitor *to_qov(Visitor *v)
  41 {
  42     return container_of(v, QObjectOutputVisitor, visitor);
  43 }
  44
  45 /* Push @value onto the stack of current QObjects being built */
  46 static void qobject_output_push_obj(QObjectOutputVisitor *qov, QObject *value,
  47                                     void *qapi)
  48 {
  49     QStackEntry *e = g_malloc0(sizeof(*e));
  50
  51     assert(qov->root);
  52     assert(value);
  53     e->value = value;
  54     e->qapi = qapi;
  55     QSLIST_INSERT_HEAD(&qov->stack, e, node);
  56 }
  57
  58 /* Pop a value off the stack of QObjects being built, and return it. */
  59 static QObject *qobject_output_pop(QObjectOutputVisitor *qov, void *qapi)
  60 {
  61     QStackEntry *e = QSLIST_FIRST(&qov->stack);
  62     QObject *value;
  63
  64     assert(e);
  65     assert(e->qapi == qapi);
  66     QSLIST_REMOVE_HEAD(&qov->stack, node);
  67     value = e->value;
  68     assert(value);
  69     g_free(e);
  70     return value;
  71 }
  72
  73 /* Add @value to the current QObject being built.
  74  * If the stack is visiting a dictionary or list, @value is now owned
  75  * by that container. Otherwise, @value is now the root.  */
  76 static void qobject_output_add_obj(QObjectOutputVisitor *qov, const char *name,
  77                                    QObject *value)
  78 {
  79     QStackEntry *e = QSLIST_FIRST(&qov->stack);
  80     QObject *cur = e ? e->value : NULL;
  81
  82     if (!cur) {
  83         /* Don't allow reuse of visitor on more than one root */
  84         assert(!qov->root);
  85         qov->root = value;
  86     } else {
  87         switch (qobject_type(cur)) {
  88         case QTYPE_QDICT:
  89             assert(name);
  90             qdict_put_obj(qobject_to_qdict(cur), name, value);
  91             break;
  92         case QTYPE_QLIST:
  93             assert(!name);
  94             qlist_append_obj(qobject_to_qlist(cur), value);
  95             break;
  96         default:
  97             g_assert_not_reached();
  98         }
  99     }
 100 }
 101
 102 static void qobject_output_start_struct(Visitor *v, const char *name,
 103                                         void **obj, size_t unused, Error **errp)
 104 {
 105     QObjectOutputVisitor *qov = to_qov(v);
 106     QDict *dict = qdict_new();
 107
 108     qobject_output_add(qov, name, dict);
 109     qobject_output_push(qov, dict, obj);
 110 }
 111
 112 static void qobject_output_end_struct(Visitor *v, void **obj)
 113 {
 114     QObjectOutputVisitor *qov = to_qov(v);
 115     QObject *value = qobject_output_pop(qov, obj);
 116     assert(qobject_type(value) == QTYPE_QDICT);
 117 }
 118
 119 static void qobject_output_start_list(Visitor *v, const char *name,
 120                                       GenericList **listp, size_t size,
 121                                       Error **errp)
 122 {
 123     QObjectOutputVisitor *qov = to_qov(v);
 124     QList *list = qlist_new();
 125
 126     qobject_output_add(qov, name, list);
 127     qobject_output_push(qov, list, listp);
 128 }
 129
 130 static GenericList *qobject_output_next_list(Visitor *v, GenericList *tail,
 131                                              size_t size)
 132 {
 133     return tail->next;
 134 }
 135
 136 static void qobject_output_end_list(Visitor *v, void **obj)
 137 {
 138     QObjectOutputVisitor *qov = to_qov(v);
 139     QObject *value = qobject_output_pop(qov, obj);
 140     assert(qobject_type(value) == QTYPE_QLIST);
 141 }
 142
 143 static void qobject_output_type_int64(Visitor *v, const char *name,
 144                                       int64_t *obj, Error **errp)
 145 {
 146     QObjectOutputVisitor *qov = to_qov(v);
 147     qobject_output_add(qov, name, qnum_from_int(*obj));
 148 }
 149
 150 static void qobject_output_type_uint64(Visitor *v, const char *name,
 151                                        uint64_t *obj, Error **errp)
 152 {
 153     QObjectOutputVisitor *qov = to_qov(v);
 154     qobject_output_add(qov, name, qnum_from_uint(*obj));
 155 }
 156
 157 static void qobject_output_type_bool(Visitor *v, const char *name, bool *obj,
 158                                      Error **errp)
 159 {
 160     QObjectOutputVisitor *qov = to_qov(v);
 161     qobject_output_add(qov, name, qbool_from_bool(*obj));
 162 }
 163
 164 static void qobject_output_type_str(Visitor *v, const char *name, char **obj,
 165                                     Error **errp)
 166 {
 167     QObjectOutputVisitor *qov = to_qov(v);
 168     if (*obj) {
 169         qobject_output_add(qov, name, qstring_from_str(*obj));
 170     } else {
 171         qobject_output_add(qov, name, qstring_from_str(""));
 172     }
 173 }
 174
 175 static void qobject_output_type_number(Visitor *v, const char *name,
 176                                        double *obj, Error **errp)
 177 {
 178     QObjectOutputVisitor *qov = to_qov(v);
 179     qobject_output_add(qov, name, qnum_from_double(*obj));
 180 }
 181
 182 static void qobject_output_type_any(Visitor *v, const char *name,
 183                                     QObject **obj, Error **errp)
 184 {
 185     QObjectOutputVisitor *qov = to_qov(v);
 186     qobject_incref(*obj);
 187     qobject_output_add_obj(qov, name, *obj);
 188 }
 189
 190 static void qobject_output_type_null(Visitor *v, const char *name, Error **errp)
 191 {
 192     QObjectOutputVisitor *qov = to_qov(v);
 193     qobject_output_add_obj(qov, name, qnull());
 194 }
 195
 196 /* Finish building, and return the root object.
 197  * The root object is never null. The caller becomes the object's
 198  * owner, and should use qobject_decref() when done with it.  */
 199 static void qobject_output_complete(Visitor *v, void *opaque)
 200 {
 201     QObjectOutputVisitor *qov = to_qov(v);
 202
 203     /* A visit must have occurred, with each start paired with end.  */
 204     assert(qov->root && QSLIST_EMPTY(&qov->stack));
 205     assert(opaque == qov->result);
 206
 207     qobject_incref(qov->root);
 208     *qov->result = qov->root;
 209     qov->result = NULL;
 210 }
 211
 212 static void qobject_output_free(Visitor *v)
 213 {
 214     QObjectOutputVisitor *qov = to_qov(v);
 215     QStackEntry *e;
 216
 217     while (!QSLIST_EMPTY(&qov->stack)) {
 218         e = QSLIST_FIRST(&qov->stack);
 219         QSLIST_REMOVE_HEAD(&qov->stack, node);
 220         g_free(e);
 221     }
 222
 223     qobject_decref(qov->root);
 224     g_free(qov);
 225 }
 226
 227 Visitor *qobject_output_visitor_new(QObject **result)
 228 {
 229     QObjectOutputVisitor *v;
 230
 231     v = g_malloc0(sizeof(*v));
 232
 233     v->visitor.type = VISITOR_OUTPUT;
 234     v->visitor.start_struct = qobject_output_start_struct;
 235     v->visitor.end_struct = qobject_output_end_struct;
 236     v->visitor.start_list = qobject_output_start_list;
 237     v->visitor.next_list = qobject_output_next_list;
 238     v->visitor.end_list = qobject_output_end_list;
 239     v->visitor.type_int64 = qobject_output_type_int64;
 240     v->visitor.type_uint64 = qobject_output_type_uint64;
 241     v->visitor.type_bool = qobject_output_type_bool;
 242     v->visitor.type_str = qobject_output_type_str;
 243     v->visitor.type_number = qobject_output_type_number;
 244     v->visitor.type_any = qobject_output_type_any;
 245     v->visitor.type_null = qobject_output_type_null;
 246     v->visitor.complete = qobject_output_complete;
 247     v->visitor.free = qobject_output_free;
 248
 249     *result = NULL;
 250     v->result = result;
 251
 252     return &v->visitor;
 253 }